fix broken dependency

[openadk.git] / target / linux / patches / 3.14.45 / mptcp.patch

diff -Nur linux-3.14.45.orig/drivers/infiniband/hw/cxgb4/cm.c linux-3.14.45/drivers/infiniband/hw/cxgb4/cm.c
--- linux-3.14.45.orig/drivers/infiniband/hw/cxgb4/cm.c 2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/drivers/infiniband/hw/cxgb4/cm.c      2015-06-24 14:15:48.871862463 +0200
@@ -3162,7 +3162,7 @@
         */
        memset(&tmp_opt, 0, sizeof(tmp_opt));
        tcp_clear_options(&tmp_opt);
-       tcp_parse_options(skb, &tmp_opt, 0, NULL);
+       tcp_parse_options(skb, &tmp_opt, NULL, 0, NULL);
 
        req = (struct cpl_pass_accept_req *)__skb_push(skb, sizeof(*req));
        memset(req, 0, sizeof(*req));
diff -Nur linux-3.14.45.orig/include/linux/ipv6.h linux-3.14.45/include/linux/ipv6.h
--- linux-3.14.45.orig/include/linux/ipv6.h     2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/linux/ipv6.h  2015-06-24 14:15:48.871862463 +0200
@@ -309,12 +309,6 @@
        return NULL;
 }
 
-static inline struct inet6_request_sock *
-                       inet6_rsk(const struct request_sock *rsk)
-{
-       return NULL;
-}
-
 static inline struct raw6_sock *raw6_sk(const struct sock *sk)
 {
        return NULL;
diff -Nur linux-3.14.45.orig/include/linux/tcp.h linux-3.14.45/include/linux/tcp.h
--- linux-3.14.45.orig/include/linux/tcp.h      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/linux/tcp.h   2015-06-24 14:15:48.871862463 +0200
@@ -72,6 +72,53 @@
        u32     end_seq;
 };
 
+struct tcp_out_options {
+       u16     options;        /* bit field of OPTION_* */
+       u8      ws;             /* window scale, 0 to disable */
+       u8      num_sack_blocks;/* number of SACK blocks to include */
+       u8      hash_size;      /* bytes in hash_location */
+       u16     mss;            /* 0 to disable */
+       __u8    *hash_location; /* temporary pointer, overloaded */
+       __u32   tsval, tsecr;   /* need to include OPTION_TS */
+       struct tcp_fastopen_cookie *fastopen_cookie;    /* Fast open cookie */
+#ifdef CONFIG_MPTCP
+       u16     mptcp_options;  /* bit field of MPTCP related OPTION_* */
+       u8      dss_csum:1,
+               add_addr_v4:1,
+               add_addr_v6:1;  /* dss-checksum required? */
+
+       __u32   data_seq;       /* data sequence number, for MPTCP */
+       __u32   data_ack;       /* data ack, for MPTCP */
+
+       union {
+               struct {
+                       __u64   sender_key;     /* sender's key for mptcp */
+                       __u64   receiver_key;   /* receiver's key for mptcp */
+               } mp_capable;
+
+               struct {
+                       __u64   sender_truncated_mac;
+                       __u32   sender_nonce;
+                                       /* random number of the sender */
+                       __u32   token;  /* token for mptcp */
+               } mp_join_syns;
+       };
+
+       struct {
+               struct in_addr addr;
+               u8 addr_id;
+       } add_addr4;
+
+       struct {
+               struct in6_addr addr;
+               u8 addr_id;
+       } add_addr6;
+
+       u16     remove_addrs;   /* list of address id */
+       u8      addr_id;        /* address id (mp_join or add_address) */
+#endif /* CONFIG_MPTCP */
+};
+
 /*These are used to set the sack_ok field in struct tcp_options_received */
 #define TCP_SACK_SEEN     (1 << 0)   /*1 = peer is SACK capable, */
 #define TCP_FACK_ENABLED  (1 << 1)   /*1 = FACK is enabled locally*/
@@ -95,6 +142,9 @@
        u16     mss_clamp;      /* Maximal mss, negotiated at connection setup */
 };
 
+struct mptcp_cb;
+struct mptcp_tcp_sock;
+
 static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
 {
        rx_opt->tstamp_ok = rx_opt->sack_ok = 0;
@@ -123,6 +173,7 @@
                                                  * FastOpen it's the seq#
                                                  * after data-in-SYN.
                                                  */
+       u8                              saw_mpc:1;
 };
 
 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
@@ -130,6 +181,8 @@
        return (struct tcp_request_sock *)req;
 }
 
+struct tcp_md5sig_key;
+
 struct tcp_sock {
        /* inet_connection_sock has to be the first member of tcp_sock */
        struct inet_connection_sock     inet_conn;
@@ -323,6 +376,45 @@
         * socket. Used to retransmit SYNACKs etc.
         */
        struct request_sock *fastopen_rsk;
+
+
+       struct mptcp_cb         *mpcb;
+       struct sock             *meta_sk;
+       /* We keep these flags even if CONFIG_MPTCP is not checked, because
+        * it allows checking MPTCP capability just by checking the mpc flag,
+        * rather than adding ifdefs everywhere.
+        */
+       u16     mpc:1,          /* Other end is multipath capable */
+               inside_tk_table:1, /* Is the tcp_sock inside the token-table? */
+               send_mp_fclose:1,
+               request_mptcp:1, /* Did we send out an MP_CAPABLE?
+                                 * (this speeds up mptcp_doit() in tcp_recvmsg)
+                                 */
+               mptcp_enabled:1, /* Is MPTCP enabled from the application ? */
+               pf:1, /* Potentially Failed state: when this flag is set, we
+                      * stop using the subflow
+                      */
+               mp_killed:1, /* Killed with a tcp_done in mptcp? */
+               was_meta_sk:1,  /* This was a meta sk (in case of reuse) */
+               close_it:1,     /* Must close socket in mptcp_data_ready? */
+               closing:1;
+       struct mptcp_tcp_sock *mptcp;
+#ifdef CONFIG_MPTCP
+       struct hlist_nulls_node tk_table;
+       u32             mptcp_loc_token;
+       u64             mptcp_loc_key;
+#endif /* CONFIG_MPTCP */
+
+       /* Functions that depend on the value of the mpc flag */
+       u32 (*__select_window)(struct sock *sk);
+       u16 (*select_window)(struct sock *sk);
+       void (*select_initial_window)(int __space, __u32 mss, __u32 *rcv_wnd,
+                                       __u32 *window_clamp, int wscale_ok,
+                                       __u8 *rcv_wscale, __u32 init_rcv_wnd,
+                                       const struct sock *sk);
+       void (*init_buffer_space)(struct sock *sk);
+       void (*set_rto)(struct sock *sk);
+       bool (*should_expand_sndbuf)(const struct sock *sk);
 };
 
 enum tsq_flags {
@@ -334,6 +426,8 @@
        TCP_MTU_REDUCED_DEFERRED,  /* tcp_v{4|6}_err() could not call
                                    * tcp_v{4|6}_mtu_reduced()
                                    */
+       MPTCP_PATH_MANAGER, /* MPTCP deferred creation of new subflows */
+       MPTCP_SUB_DEFERRED, /* A subflow got deferred - process them */
 };
 
 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
@@ -352,6 +446,7 @@
 #ifdef CONFIG_TCP_MD5SIG
        struct tcp_md5sig_key     *tw_md5_key;
 #endif
+       struct mptcp_tw           *mptcp_tw;
 };
 
 static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
diff -Nur linux-3.14.45.orig/include/net/inet6_connection_sock.h linux-3.14.45/include/net/inet6_connection_sock.h
--- linux-3.14.45.orig/include/net/inet6_connection_sock.h      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/net/inet6_connection_sock.h   2015-06-24 14:15:48.871862463 +0200
@@ -27,6 +27,8 @@
 
 struct dst_entry *inet6_csk_route_req(struct sock *sk, struct flowi6 *fl6,
                                      const struct request_sock *req);
+u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport,
+                   const u32 rnd, const u32 synq_hsize);
 
 struct request_sock *inet6_csk_search_req(const struct sock *sk,
                                          struct request_sock ***prevp,
diff -Nur linux-3.14.45.orig/include/net/inet_common.h linux-3.14.45/include/net/inet_common.h
--- linux-3.14.45.orig/include/net/inet_common.h        2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/net/inet_common.h     2015-06-24 14:15:48.871862463 +0200
@@ -1,6 +1,8 @@
 #ifndef _INET_COMMON_H
 #define _INET_COMMON_H
 
+#include <net/sock.h>
+
 extern const struct proto_ops inet_stream_ops;
 extern const struct proto_ops inet_dgram_ops;
 
@@ -13,6 +15,8 @@
 struct sockaddr;
 struct socket;
 
+int inet_create(struct net *net, struct socket *sock, int protocol, int kern);
+int inet6_create(struct net *net, struct socket *sock, int protocol, int kern);
 int inet_release(struct socket *sock);
 int inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
                        int addr_len, int flags);
diff -Nur linux-3.14.45.orig/include/net/inet_connection_sock.h linux-3.14.45/include/net/inet_connection_sock.h
--- linux-3.14.45.orig/include/net/inet_connection_sock.h       2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/net/inet_connection_sock.h    2015-06-24 14:15:48.871862463 +0200
@@ -244,6 +244,9 @@
 
 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);
 
+u32 inet_synq_hash(const __be32 raddr, const __be16 rport, const u32 rnd,
+                  const u32 synq_hsize);
+
 struct request_sock *inet_csk_search_req(const struct sock *sk,
                                         struct request_sock ***prevp,
                                         const __be16 rport,
diff -Nur linux-3.14.45.orig/include/net/mptcp.h linux-3.14.45/include/net/mptcp.h
--- linux-3.14.45.orig/include/net/mptcp.h      1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/include/net/mptcp.h   2015-06-24 14:15:48.871862463 +0200
@@ -0,0 +1,1471 @@
+/*
+ *     MPTCP implementation
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _MPTCP_H
+#define _MPTCP_H
+
+#include <linux/inetdevice.h>
+#include <linux/ipv6.h>
+#include <linux/list.h>
+#include <linux/net.h>
+#include <linux/netpoll.h>
+#include <linux/skbuff.h>
+#include <linux/socket.h>
+#include <linux/tcp.h>
+#include <linux/kernel.h>
+
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+#include <crypto/hash.h>
+#include <net/tcp.h>
+
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       #define ntohll(x)  be64_to_cpu(x)
+       #define htonll(x)  cpu_to_be64(x)
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       #define ntohll(x) (x)
+       #define htonll(x) (x)
+#endif
+
+/* Max number of local or remote addresses we can store.
+ * When changing, see the bitfield below in mptcp_loc4/6. */
+#define MPTCP_MAX_ADDR 8
+
+#define MPTCP_SUBFLOW_RETRY_DELAY      1000
+
+struct mptcp_loc4 {
+       u8              loc4_id;
+       u8              low_prio:1;
+       struct in_addr  addr;
+};
+
+struct mptcp_rem4 {
+       u8              rem4_id;
+       u8              bitfield;
+       u8              retry_bitfield;
+       __be16          port;
+       struct in_addr  addr;
+};
+
+struct mptcp_loc6 {
+       u8              loc6_id;
+       u8              low_prio:1;
+       struct in6_addr addr;
+};
+
+struct mptcp_rem6 {
+       u8              rem6_id;
+       u8              bitfield;
+       u8              retry_bitfield;
+       __be16          port;
+       struct in6_addr addr;
+};
+
+struct mptcp_request_sock {
+       struct tcp_request_sock         req;
+       struct mptcp_cb                 *mpcb;
+       /* Collision list in the tuple hashtable. We need to find
+        * the req sock when receiving the third msg of the 3-way handshake,
+        * since that one does not contain the token. If this makes
+        * the request sock too long, we can use kmalloc'ed specific entries for
+        * that tuple hashtable. At the moment, though, I extend the
+        * request_sock.
+        */
+       struct list_head                collide_tuple;
+       struct hlist_nulls_node         collide_tk;
+       u32                             mptcp_rem_nonce;
+       u32                             mptcp_loc_token;
+       u64                             mptcp_loc_key;
+       u64                             mptcp_rem_key;
+       u64                             mptcp_hash_tmac;
+       u32                             mptcp_loc_nonce;
+       u8                              loc_id;
+       u8                              rem_id; /* Address-id in the MP_JOIN */
+       u8                              dss_csum:1,
+                                       low_prio:1;
+};
+
+struct mptcp_options_received {
+       u16     saw_mpc:1,
+               dss_csum:1,
+               drop_me:1,
+
+               is_mp_join:1,
+               join_ack:1,
+
+               saw_low_prio:2, /* 0x1 - low-prio set for this subflow
+                                * 0x2 - low-prio set for another subflow
+                                */
+               low_prio:1,
+
+               saw_add_addr:2, /* Saw at least one add_addr option:
+                                * 0x1: IPv4 - 0x2: IPv6
+                                */
+               more_add_addr:1, /* Saw one more add-addr. */
+
+               saw_rem_addr:1, /* Saw at least one rem_addr option */
+               more_rem_addr:1, /* Saw one more rem-addr. */
+
+               mp_fail:1,
+               mp_fclose:1;
+       u8      rem_id;         /* Address-id in the MP_JOIN */
+       u8      prio_addr_id;   /* Address-id in the MP_PRIO */
+
+       const unsigned char *add_addr_ptr; /* Pointer to add-address option */
+       const unsigned char *rem_addr_ptr; /* Pointer to rem-address option */
+
+       u32     data_ack;
+       u32     data_seq;
+       u16     data_len;
+
+       u32     mptcp_rem_token;/* Remote token */
+
+       /* Key inside the option (from mp_capable or fast_close) */
+       u64     mptcp_key;
+
+       u32     mptcp_recv_nonce;
+       u64     mptcp_recv_tmac;
+       u8      mptcp_recv_mac[20];
+};
+
+struct mptcp_tcp_sock {
+       struct tcp_sock *next;          /* Next subflow socket */
+       struct list_head cb_list;
+       struct mptcp_options_received rx_opt;
+
+        /* Those three fields record the current mapping */
+       u64     map_data_seq;
+       u32     map_subseq;
+       u16     map_data_len;
+       u16     slave_sk:1,
+               fully_established:1,
+               establish_increased:1,
+               second_packet:1,
+               attached:1,
+               send_mp_fail:1,
+               include_mpc:1,
+               mapping_present:1,
+               map_data_fin:1,
+               low_prio:1, /* use this socket as backup */
+               rcv_low_prio:1, /* Peer sent low-prio option to us */
+               send_mp_prio:1, /* Trigger to send mp_prio on this socket */
+               pre_established:1; /* State between sending 3rd ACK and
+                                   * receiving the fourth ack of new subflows.
+                                   */
+
+       /* isn: needed to translate abs to relative subflow seqnums */
+       u32     snt_isn;
+       u32     rcv_isn;
+       u32     last_data_seq;
+       u8      path_index;
+       u8      loc_id;
+       u8      rem_id;
+
+       u32     last_rbuf_opti; /* Timestamp of last rbuf optimization */
+       unsigned int sent_pkts;
+
+       struct sk_buff  *shortcut_ofoqueue; /* Shortcut to the current modified
+                                            * skb in the ofo-queue.
+                                            */
+
+       int     init_rcv_wnd;
+       u32     infinite_cutoff_seq;
+       struct delayed_work work;
+       u32     mptcp_loc_nonce;
+       struct tcp_sock *tp; /* Where is my daddy? */
+       u32     last_end_data_seq;
+
+       /* MP_JOIN subflow: timer for retransmitting the 3rd ack */
+       struct timer_list mptcp_ack_timer;
+
+       /* HMAC of the third ack */
+       char sender_mac[20];
+};
+
+struct mptcp_tw {
+       struct list_head list;
+       u64 loc_key;
+       u64 rcv_nxt;
+       struct mptcp_cb __rcu *mpcb;
+       u8 meta_tw:1,
+          in_list:1;
+};
+
+#define MPTCP_PM_NAME_MAX 16
+struct mptcp_pm_ops {
+       struct list_head list;
+
+       /* Signal the creation of a new MPTCP-session. */
+       void (*new_session)(struct sock *meta_sk, int index);
+       void (*release_sock)(struct sock *meta_sk);
+       void (*fully_established)(struct sock *meta_sk);
+       void (*new_remote_address)(struct sock *meta_sk);
+       int  (*get_local_index)(sa_family_t family, union inet_addr *addr,
+                               struct net *net);
+       int  (*get_local_id)(sa_family_t family, union inet_addr *addr,
+                            struct net *net);
+       void (*addr_signal)(struct sock *sk, unsigned *size,
+                           struct tcp_out_options *opts, struct sk_buff *skb);
+
+       char            name[MPTCP_PM_NAME_MAX];
+       struct module   *owner;
+};
+
+struct mptcp_cb {
+       struct sock *meta_sk;
+
+       /* list of sockets in this multipath connection */
+       struct tcp_sock *connection_list;
+       /* list of sockets that need a call to release_cb */
+       struct list_head callback_list;
+
+       spinlock_t       tw_lock;
+       struct list_head tw_list;
+       unsigned char    mptw_state;
+
+       atomic_t        mpcb_refcnt;
+
+       /* High-order bits of 64-bit sequence numbers */
+       u32 snd_high_order[2];
+       u32 rcv_high_order[2];
+
+       u16     send_infinite_mapping:1,
+               in_time_wait:1,
+               list_rcvd:1, /* XXX TO REMOVE */
+               dss_csum:1,
+               server_side:1,
+               infinite_mapping_rcv:1,
+               infinite_mapping_snd:1,
+               dfin_combined:1,   /* Was the DFIN combined with subflow-fin? */
+               passive_close:1,
+               snd_hiseq_index:1, /* Index in snd_high_order of snd_nxt */
+               rcv_hiseq_index:1; /* Index in rcv_high_order of rcv_nxt */
+
+       /* socket count in this connection */
+       u8 cnt_subflows;
+       u8 cnt_established;
+
+       u32 noneligible;        /* Path mask of temporarily non
+                                * eligible subflows by the scheduler
+                                */
+
+       struct sk_buff_head reinject_queue;
+
+       u8 dfin_path_index;
+
+#define MPTCP_PM_SIZE 320
+       u8 mptcp_pm[MPTCP_PM_SIZE] __aligned(8);
+       struct mptcp_pm_ops *pm_ops;
+
+       /* Mutex needed, because otherwise mptcp_close will complain that the
+        * socket is owned by the user.
+        * E.g., mptcp_sub_close_wq is taking the meta-lock.
+        */
+       struct mutex mpcb_mutex;
+
+       /* Master socket, also part of the connection_list, this
+        * socket is the one that the application sees.
+        */
+       struct sock *master_sk;
+
+       u64     csum_cutoff_seq;
+
+       __u64   mptcp_loc_key;
+       __u32   mptcp_loc_token;
+       __u64   mptcp_rem_key;
+       __u32   mptcp_rem_token;
+
+       /* Create a new subflow - necessary because the meta-sk may be IPv4, but
+        * the new subflow can be IPv6
+        */
+       struct sock *(*syn_recv_sock)(struct sock *sk, struct sk_buff *skb,
+                                     struct request_sock *req,
+                                     struct dst_entry *dst);
+
+       /* Remote addresses */
+       struct mptcp_rem4 remaddr4[MPTCP_MAX_ADDR];
+       u8 rem4_bits;
+
+       struct mptcp_rem6 remaddr6[MPTCP_MAX_ADDR];
+       u8 rem6_bits;
+
+       u32 path_index_bits;
+       /* Next pi to pick up in case a new path becomes available */
+       u8 next_path_index;
+
+       /* Original snd/rcvbuf of the initial subflow.
+        * Used for the new subflows on the server-side to allow correct
+        * autotuning
+        */
+       int orig_sk_rcvbuf;
+       int orig_sk_sndbuf;
+       u32 orig_window_clamp;
+};
+
+#define MPTCP_SUB_CAPABLE                      0
+#define MPTCP_SUB_LEN_CAPABLE_SYN              12
+#define MPTCP_SUB_LEN_CAPABLE_SYN_ALIGN                12
+#define MPTCP_SUB_LEN_CAPABLE_ACK              20
+#define MPTCP_SUB_LEN_CAPABLE_ACK_ALIGN                20
+
+#define MPTCP_SUB_JOIN                 1
+#define MPTCP_SUB_LEN_JOIN_SYN         12
+#define MPTCP_SUB_LEN_JOIN_SYN_ALIGN   12
+#define MPTCP_SUB_LEN_JOIN_SYNACK      16
+#define MPTCP_SUB_LEN_JOIN_SYNACK_ALIGN        16
+#define MPTCP_SUB_LEN_JOIN_ACK         24
+#define MPTCP_SUB_LEN_JOIN_ACK_ALIGN   24
+
+#define MPTCP_SUB_DSS          2
+#define MPTCP_SUB_LEN_DSS      4
+#define MPTCP_SUB_LEN_DSS_ALIGN        4
+
+/* Lengths for seq and ack are the ones without the generic MPTCP-option header,
+ * as they are part of the DSS-option.
+ * To get the total length, just add the different options together.
+ */
+#define MPTCP_SUB_LEN_SEQ      10
+#define MPTCP_SUB_LEN_SEQ_CSUM 12
+#define MPTCP_SUB_LEN_SEQ_ALIGN        12
+
+#define MPTCP_SUB_LEN_SEQ_64           14
+#define MPTCP_SUB_LEN_SEQ_CSUM_64      16
+#define MPTCP_SUB_LEN_SEQ_64_ALIGN     16
+
+#define MPTCP_SUB_LEN_ACK      4
+#define MPTCP_SUB_LEN_ACK_ALIGN        4
+
+#define MPTCP_SUB_LEN_ACK_64           8
+#define MPTCP_SUB_LEN_ACK_64_ALIGN     8
+
+/* This is the "default" option-length we will send out most often.
+ * MPTCP DSS-header
+ * 32-bit data sequence number
+ * 32-bit data ack
+ *
+ * It is necessary to calculate the effective MSS we will be using when
+ * sending data.
+ */
+#define MPTCP_SUB_LEN_DSM_ALIGN  (MPTCP_SUB_LEN_DSS_ALIGN +            \
+                                 MPTCP_SUB_LEN_SEQ_ALIGN +             \
+                                 MPTCP_SUB_LEN_ACK_ALIGN)
+
+#define MPTCP_SUB_ADD_ADDR             3
+#define MPTCP_SUB_LEN_ADD_ADDR4                8
+#define MPTCP_SUB_LEN_ADD_ADDR6                20
+#define MPTCP_SUB_LEN_ADD_ADDR4_ALIGN  8
+#define MPTCP_SUB_LEN_ADD_ADDR6_ALIGN  20
+
+#define MPTCP_SUB_REMOVE_ADDR  4
+#define MPTCP_SUB_LEN_REMOVE_ADDR      4
+
+#define MPTCP_SUB_PRIO         5
+#define MPTCP_SUB_LEN_PRIO     3
+#define MPTCP_SUB_LEN_PRIO_ADDR        4
+#define MPTCP_SUB_LEN_PRIO_ALIGN       4
+
+#define MPTCP_SUB_FAIL         6
+#define MPTCP_SUB_LEN_FAIL     12
+#define MPTCP_SUB_LEN_FAIL_ALIGN       12
+
+#define MPTCP_SUB_FCLOSE       7
+#define MPTCP_SUB_LEN_FCLOSE   12
+#define MPTCP_SUB_LEN_FCLOSE_ALIGN     12
+
+
+#define OPTION_MPTCP           (1 << 5)
+
+static inline void reset_mpc(struct tcp_sock *tp)
+{
+       tp->mpc = 0;
+
+       tp->__select_window             = __tcp_select_window;
+       tp->select_window               = tcp_select_window;
+       tp->select_initial_window       = tcp_select_initial_window;
+       tp->init_buffer_space           = tcp_init_buffer_space;
+       tp->set_rto                     = tcp_set_rto;
+       tp->should_expand_sndbuf        = tcp_should_expand_sndbuf;
+}
+
+/* Initializes MPTCP flags in tcp_sock (and other tcp_sock members that depend
+ * on those flags).
+ */
+static inline void mptcp_init_tcp_sock(struct tcp_sock *tp)
+{
+       reset_mpc(tp);
+}
+
+#ifdef CONFIG_MPTCP
+
+/* Used for checking if the mptcp initialization has been successful */
+extern bool mptcp_init_failed;
+
+/* MPTCP options */
+#define OPTION_TYPE_SYN                (1 << 0)
+#define OPTION_TYPE_SYNACK     (1 << 1)
+#define OPTION_TYPE_ACK                (1 << 2)
+#define OPTION_MP_CAPABLE      (1 << 3)
+#define OPTION_DATA_ACK                (1 << 4)
+#define OPTION_ADD_ADDR                (1 << 5)
+#define OPTION_MP_JOIN         (1 << 6)
+#define OPTION_MP_FAIL         (1 << 7)
+#define OPTION_MP_FCLOSE       (1 << 8)
+#define OPTION_REMOVE_ADDR     (1 << 9)
+#define OPTION_MP_PRIO         (1 << 10)
+
+/* MPTCP flags */
+#define MPTCPHDR_ACK           0x01
+#define MPTCPHDR_SEQ           0x02
+#define MPTCPHDR_FIN           0x04
+#define MPTCPHDR_INF           0x08
+#define MPTCPHDR_SEQ64_SET     0x10 /* Did we received a 64-bit seq number */
+#define MPTCPHDR_SEQ64_OFO     0x20 /* Is it not in our circular array? */
+#define MPTCPHDR_SEQ64_INDEX   0x40 /* Index of seq in mpcb->snd_high_order */
+#define MPTCPHDR_DSS_CSUM      0x80
+
+/* It is impossible, that all 8 bits of mptcp_flags are set to 1 with the above
+ * Thus, defining MPTCPHDR_JOIN as 0xFF is safe.
+ */
+#define MPTCPHDR_JOIN          0xFF
+
+struct mptcp_option {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u8    ver:4,
+               sub:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u8    sub:4,
+               ver:4;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+};
+
+struct mp_capable {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u8    ver:4,
+               sub:4;
+       __u8    h:1,
+               rsv:5,
+               b:1,
+               a:1;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u8    sub:4,
+               ver:4;
+       __u8    a:1,
+               b:1,
+               rsv:5,
+               h:1;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+       __u64   sender_key;
+       __u64   receiver_key;
+} __attribute__((__packed__));
+
+struct mp_join {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u8    b:1,
+               rsv:3,
+               sub:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u8    sub:4,
+               rsv:3,
+               b:1;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+       __u8    addr_id;
+       union {
+               struct {
+                       u32     token;
+                       u32     nonce;
+               } syn;
+               struct {
+                       __u64   mac;
+                       u32     nonce;
+               } synack;
+               struct {
+                       __u8    mac[20];
+               } ack;
+       } u;
+} __attribute__((__packed__));
+
+struct mp_dss {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u16   rsv1:4,
+               sub:4,
+               A:1,
+               a:1,
+               M:1,
+               m:1,
+               F:1,
+               rsv2:3;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u16   sub:4,
+               rsv1:4,
+               rsv2:3,
+               F:1,
+               m:1,
+               M:1,
+               a:1,
+               A:1;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+};
+
+struct mp_add_addr {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u8    ipver:4,
+               sub:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u8    sub:4,
+               ipver:4;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+       __u8    addr_id;
+       union {
+               struct {
+                       struct in_addr  addr;
+                       __be16          port;
+               } v4;
+               struct {
+                       struct in6_addr addr;
+                       __be16          port;
+               } v6;
+       } u;
+} __attribute__((__packed__));
+
+struct mp_remove_addr {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u8    rsv:4,
+               sub:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u8    sub:4,
+               rsv:4;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+       /* list of addr_id */
+       __u8    addrs_id;
+};
+
+struct mp_fail {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u16   rsv1:4,
+               sub:4,
+               rsv2:8;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u16   sub:4,
+               rsv1:4,
+               rsv2:8;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+       __be64  data_seq;
+} __attribute__((__packed__));
+
+struct mp_fclose {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u16   rsv1:4,
+               sub:4,
+               rsv2:8;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u16   sub:4,
+               rsv1:4,
+               rsv2:8;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+       __u64   key;
+} __attribute__((__packed__));
+
+struct mp_prio {
+       __u8    kind;
+       __u8    len;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       __u8    b:1,
+               rsv:3,
+               sub:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       __u8    sub:4,
+               rsv:3,
+               b:1;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+       __u8    addr_id;
+} __attribute__((__packed__));
+
+static inline int mptcp_sub_len_dss(struct mp_dss *m, int csum)
+{
+       return 4 + m->A * (4 + m->a * 4) + m->M * (10 + m->m * 4 + csum * 2);
+}
+
+#define MPTCP_APP      2
+
+extern int sysctl_mptcp_enabled;
+extern int sysctl_mptcp_checksum;
+extern int sysctl_mptcp_debug;
+extern int sysctl_mptcp_syn_retries;
+
+extern struct workqueue_struct *mptcp_wq;
+
+#define mptcp_debug(fmt, args...)                                      \
+       do {                                                            \
+               if (unlikely(sysctl_mptcp_debug))                       \
+                       pr_err(__FILE__ ": " fmt, ##args);      \
+       } while (0)
+
+/* Iterates over all subflows */
+#define mptcp_for_each_tp(mpcb, tp)                                    \
+       for ((tp) = (mpcb)->connection_list; (tp); (tp) = (tp)->mptcp->next)
+
+#define mptcp_for_each_sk(mpcb, sk)                                    \
+       for ((sk) = (struct sock *)(mpcb)->connection_list;             \
+            sk;                                                        \
+            sk = (struct sock *)tcp_sk(sk)->mptcp->next)
+
+#define mptcp_for_each_sk_safe(__mpcb, __sk, __temp)                   \
+       for (__sk = (struct sock *)(__mpcb)->connection_list,           \
+            __temp = __sk ? (struct sock *)tcp_sk(__sk)->mptcp->next : NULL; \
+            __sk;                                                      \
+            __sk = __temp,                                             \
+            __temp = __sk ? (struct sock *)tcp_sk(__sk)->mptcp->next : NULL)
+
+/* Iterates over all bit set to 1 in a bitset */
+#define mptcp_for_each_bit_set(b, i)                                   \
+       for (i = ffs(b) - 1; i >= 0; i = ffs(b >> (i + 1) << (i + 1)) - 1)
+
+#define mptcp_for_each_bit_unset(b, i)                                 \
+       mptcp_for_each_bit_set(~b, i)
+
+extern struct lock_class_key meta_key;
+extern struct lock_class_key meta_slock_key;
+extern u32 mptcp_secret[MD5_MESSAGE_BYTES / 4];
+
+/* This is needed to ensure that two subsequent key-generation result in
+ * different keys if the IPs and ports are the same.
+ */
+extern u32 mptcp_key_seed;
+
+#define MPTCP_HASH_SIZE                1024
+
+extern struct hlist_nulls_head tk_hashtable[MPTCP_HASH_SIZE];
+
+/* This second hashtable is needed to retrieve request socks
+ * created as a result of a join request. While the SYN contains
+ * the token, the final ack does not, so we need a separate hashtable
+ * to retrieve the mpcb.
+ */
+extern struct list_head mptcp_reqsk_htb[MPTCP_HASH_SIZE];
+extern spinlock_t mptcp_reqsk_hlock;   /* hashtable protection */
+
+/* Lock, protecting the two hash-tables that hold the token. Namely,
+ * mptcp_reqsk_tk_htb and tk_hashtable
+ */
+extern spinlock_t mptcp_tk_hashlock;   /* hashtable protection */
+
+void mptcp_data_ready(struct sock *sk, int bytes);
+void mptcp_write_space(struct sock *sk);
+
+void mptcp_add_meta_ofo_queue(struct sock *meta_sk, struct sk_buff *skb,
+                             struct sock *sk);
+void mptcp_ofo_queue(struct sock *meta_sk);
+void mptcp_purge_ofo_queue(struct tcp_sock *meta_tp);
+void mptcp_cleanup_rbuf(struct sock *meta_sk, int copied);
+int mptcp_alloc_mpcb(struct sock *master_sk, __u64 remote_key, u32 window);
+int mptcp_add_sock(struct sock *meta_sk, struct sock *sk, u8 loc_id, u8 rem_id,
+                  gfp_t flags);
+void mptcp_del_sock(struct sock *sk);
+void mptcp_update_metasocket(struct sock *sock, struct sock *meta_sk);
+void mptcp_reinject_data(struct sock *orig_sk, int clone_it);
+void mptcp_update_sndbuf(struct mptcp_cb *mpcb);
+struct sk_buff *mptcp_next_segment(struct sock *sk, int *reinject);
+void mptcp_send_fin(struct sock *meta_sk);
+void mptcp_send_active_reset(struct sock *meta_sk, gfp_t priority);
+int mptcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
+                    int push_one, gfp_t gfp);
+void mptcp_parse_options(const uint8_t *ptr, int opsize,
+                        struct tcp_options_received *opt_rx,
+                        struct mptcp_options_received *mopt,
+                        const struct sk_buff *skb);
+void mptcp_syn_options(struct sock *sk, struct tcp_out_options *opts,
+                      unsigned *remaining);
+void mptcp_synack_options(struct request_sock *req,
+                         struct tcp_out_options *opts,
+                         unsigned *remaining);
+void mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+                              struct tcp_out_options *opts, unsigned *size);
+void mptcp_options_write(__be32 *ptr, struct tcp_sock *tp,
+                        struct tcp_out_options *opts,
+                        struct sk_buff *skb);
+void mptcp_close(struct sock *meta_sk, long timeout);
+int mptcp_doit(struct sock *sk);
+int mptcp_create_master_sk(struct sock *meta_sk, __u64 remote_key, u32 window);
+int mptcp_check_req_master(struct sock *sk, struct sock *child,
+                          struct request_sock *req,
+                          struct request_sock **prev,
+                          struct mptcp_options_received *mopt);
+struct sock *mptcp_check_req_child(struct sock *sk, struct sock *child,
+                                  struct request_sock *req,
+                                  struct request_sock **prev,
+                                  struct mptcp_options_received *mopt);
+u32 __mptcp_select_window(struct sock *sk);
+void mptcp_select_initial_window(int __space, __u32 mss, __u32 *rcv_wnd,
+                                       __u32 *window_clamp, int wscale_ok,
+                                       __u8 *rcv_wscale, __u32 init_rcv_wnd,
+                                       const struct sock *sk);
+unsigned int mptcp_current_mss(struct sock *meta_sk);
+int mptcp_select_size(const struct sock *meta_sk, bool sg);
+void mptcp_key_sha1(u64 key, u32 *token, u64 *idsn);
+void mptcp_hmac_sha1(u8 *key_1, u8 *key_2, u8 *rand_1, u8 *rand_2,
+                    u32 *hash_out);
+void mptcp_clean_rtx_infinite(struct sk_buff *skb, struct sock *sk);
+void mptcp_fin(struct sock *meta_sk);
+void mptcp_retransmit_timer(struct sock *meta_sk);
+int mptcp_write_wakeup(struct sock *meta_sk);
+void mptcp_sub_close_wq(struct work_struct *work);
+void mptcp_sub_close(struct sock *sk, unsigned long delay);
+struct sock *mptcp_select_ack_sock(const struct sock *meta_sk, int copied);
+void mptcp_fallback_meta_sk(struct sock *meta_sk);
+int mptcp_backlog_rcv(struct sock *meta_sk, struct sk_buff *skb);
+struct sock *mptcp_sk_clone(const struct sock *sk, int family, const gfp_t priority);
+void mptcp_ack_handler(unsigned long);
+int mptcp_check_rtt(const struct tcp_sock *tp, int time);
+int mptcp_check_snd_buf(const struct tcp_sock *tp);
+int mptcp_handle_options(struct sock *sk, const struct tcphdr *th, struct sk_buff *skb);
+void __init mptcp_init(void);
+int mptcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len);
+int mptcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
+                  unsigned int mss_now, int reinject);
+int mptso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
+                  unsigned int mss_now, gfp_t gfp, int reinject);
+void mptcp_destroy_sock(struct sock *sk);
+int mptcp_rcv_synsent_state_process(struct sock *sk, struct sock **skptr,
+                                   struct sk_buff *skb,
+                                   struct mptcp_options_received *mopt);
+unsigned int mptcp_xmit_size_goal(struct sock *meta_sk, u32 mss_now,
+                                 int large_allowed);
+int mptcp_time_wait(struct sock *sk, struct tcp_timewait_sock *tw);
+void mptcp_twsk_destructor(struct tcp_timewait_sock *tw);
+void mptcp_update_tw_socks(const struct tcp_sock *tp, int state);
+void mptcp_disconnect(struct sock *sk);
+bool mptcp_should_expand_sndbuf(const struct sock *sk);
+int mptcp_retransmit_skb(struct sock *meta_sk, struct sk_buff *skb);
+void mptcp_tsq_flags(struct sock *sk);
+void mptcp_tsq_sub_deferred(struct sock *meta_sk);
+struct mp_join *mptcp_find_join(struct sk_buff *skb);
+void mptcp_hash_remove_bh(struct tcp_sock *meta_tp);
+void mptcp_hash_remove(struct tcp_sock *meta_tp);
+struct sock *mptcp_hash_find(struct net *net, u32 token);
+int mptcp_lookup_join(struct sk_buff *skb, struct inet_timewait_sock *tw);
+int mptcp_do_join_short(struct sk_buff *skb, struct mptcp_options_received *mopt,
+                       struct tcp_options_received *tmp_opt, struct net *net);
+void mptcp_reqsk_destructor(struct request_sock *req);
+void mptcp_reqsk_new_mptcp(struct request_sock *req,
+                          const struct tcp_options_received *rx_opt,
+                          const struct mptcp_options_received *mopt,
+                          const struct sk_buff *skb);
+int mptcp_check_req(struct sk_buff *skb, struct net *net);
+void mptcp_connect_init(struct sock *sk);
+void mptcp_sub_force_close(struct sock *sk);
+int mptcp_sub_len_remove_addr_align(u16 bitfield);
+void mptcp_remove_shortcuts(const struct mptcp_cb *mpcb,
+                           const struct sk_buff *skb);
+void mptcp_init_buffer_space(struct sock *sk);
+
+/* MPTCP-path-manager registration/initialization functions */
+int mptcp_register_path_manager(struct mptcp_pm_ops *pm);
+void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm);
+void mptcp_init_path_manager(struct mptcp_cb *mpcb);
+void mptcp_cleanup_path_manager(struct mptcp_cb *mpcb);
+void mptcp_fallback_default(struct mptcp_cb *mpcb);
+void mptcp_get_default_path_manager(char *name);
+int mptcp_set_default_path_manager(const char *name);
+extern struct mptcp_pm_ops mptcp_pm_default;
+
+static inline
+struct mptcp_request_sock *mptcp_rsk(const struct request_sock *req)
+{
+       return (struct mptcp_request_sock *)req;
+}
+
+static inline
+struct request_sock *rev_mptcp_rsk(const struct mptcp_request_sock *req)
+{
+       return (struct request_sock *)req;
+}
+
+static inline bool mptcp_can_sendpage(struct sock *sk)
+{
+       struct sock *sk_it;
+
+       if (tcp_sk(sk)->mpcb->dss_csum)
+               return false;
+
+       mptcp_for_each_sk(tcp_sk(sk)->mpcb, sk_it) {
+               if (!(sk_it->sk_route_caps & NETIF_F_SG) ||
+                   !(sk_it->sk_route_caps & NETIF_F_ALL_CSUM))
+                       return false;
+       }
+
+       return true;
+}
+
+static inline void mptcp_push_pending_frames(struct sock *meta_sk)
+{
+       if (mptcp_next_segment(meta_sk, NULL)) {
+               struct tcp_sock *tp = tcp_sk(meta_sk);
+
+               /* We don't care about the MSS, because it will be set in
+                * mptcp_write_xmit.
+                */
+               __tcp_push_pending_frames(meta_sk, 0, tp->nonagle);
+       }
+}
+
+static inline void mptcp_send_reset(struct sock *sk)
+{
+       tcp_send_active_reset(sk, GFP_ATOMIC);
+       mptcp_sub_force_close(sk);
+}
+
+static inline int mptcp_is_data_seq(const struct sk_buff *skb)
+{
+       return TCP_SKB_CB(skb)->mptcp_flags & MPTCPHDR_SEQ;
+}
+
+static inline int mptcp_is_data_fin(const struct sk_buff *skb)
+{
+       return mptcp_is_data_seq(skb) &&
+              (TCP_SKB_CB(skb)->mptcp_flags & MPTCPHDR_FIN);
+}
+
+/* Is it a data-fin while in infinite mapping mode?
+ * In infinite mode, a subflow-fin is in fact a data-fin.
+ */
+static inline int mptcp_is_data_fin2(const struct sk_buff *skb,
+                                    const struct tcp_sock *tp)
+{
+       return mptcp_is_data_fin(skb) ||
+              (tp->mpcb->infinite_mapping_rcv && tcp_hdr(skb)->fin);
+}
+
+static inline void mptcp_skb_entail_init(const struct tcp_sock *tp,
+                                        struct sk_buff *skb)
+{
+               TCP_SKB_CB(skb)->mptcp_flags = MPTCPHDR_SEQ;
+}
+
+static inline u8 mptcp_get_64_bit(u64 data_seq, struct mptcp_cb *mpcb)
+{
+       u64 data_seq_high = (u32)(data_seq >> 32);
+
+       if (mpcb->rcv_high_order[0] == data_seq_high)
+               return 0;
+       else if (mpcb->rcv_high_order[1] == data_seq_high)
+               return MPTCPHDR_SEQ64_INDEX;
+       else
+               return MPTCPHDR_SEQ64_OFO;
+}
+
+/* Sets the data_seq and returns pointer to the in-skb field of the data_seq.
+ * If the packet has a 64-bit dseq, the pointer points to the last 32 bits.
+ */
+static inline __u32 *mptcp_skb_set_data_seq(const struct sk_buff *skb,
+                                           u32 *data_seq,
+                                           struct mptcp_cb *mpcb)
+{
+       __u32 *ptr = (__u32 *)(skb_transport_header(skb) + TCP_SKB_CB(skb)->dss_off);
+
+       if (TCP_SKB_CB(skb)->mptcp_flags & MPTCPHDR_SEQ64_SET) {
+               u64 data_seq64 = get_unaligned_be64(ptr);
+
+               if (mpcb)
+                       TCP_SKB_CB(skb)->mptcp_flags |= mptcp_get_64_bit(data_seq64, mpcb);
+
+               *data_seq = (u32)data_seq64 ;
+               ptr++;
+       } else {
+               *data_seq = get_unaligned_be32(ptr);
+       }
+
+       return ptr;
+}
+
+static inline struct sock *mptcp_meta_sk(const struct sock *sk)
+{
+       return tcp_sk(sk)->meta_sk;
+}
+
+static inline struct tcp_sock *mptcp_meta_tp(const struct tcp_sock *tp)
+{
+       return tcp_sk(tp->meta_sk);
+}
+
+static inline int is_meta_tp(const struct tcp_sock *tp)
+{
+       return tp->mpcb && mptcp_meta_tp(tp) == tp;
+}
+
+static inline int is_meta_sk(const struct sock *sk)
+{
+       return sk->sk_type == SOCK_STREAM  && sk->sk_protocol == IPPROTO_TCP &&
+              tcp_sk(sk)->mpc && mptcp_meta_sk(sk) == sk;
+}
+
+static inline int is_master_tp(const struct tcp_sock *tp)
+{
+       return !tp->mpc || (!tp->mptcp->slave_sk && !is_meta_tp(tp));
+}
+
+static inline void mptcp_hash_request_remove(struct request_sock *req)
+{
+       int in_softirq = 0;
+
+       if (list_empty(&mptcp_rsk(req)->collide_tuple))
+               return;
+
+       if (in_softirq()) {
+               spin_lock(&mptcp_reqsk_hlock);
+               in_softirq = 1;
+       } else {
+               spin_lock_bh(&mptcp_reqsk_hlock);
+       }
+
+       list_del(&mptcp_rsk(req)->collide_tuple);
+
+       if (in_softirq)
+               spin_unlock(&mptcp_reqsk_hlock);
+       else
+               spin_unlock_bh(&mptcp_reqsk_hlock);
+}
+
+static inline void mptcp_init_mp_opt(struct mptcp_options_received *mopt)
+{
+       mopt->saw_mpc = 0;
+       mopt->dss_csum = 0;
+       mopt->drop_me = 0;
+
+       mopt->is_mp_join = 0;
+       mopt->join_ack = 0;
+
+       mopt->saw_low_prio = 0;
+       mopt->low_prio = 0;
+
+       mopt->saw_add_addr = 0;
+       mopt->more_add_addr = 0;
+
+       mopt->saw_rem_addr = 0;
+       mopt->more_rem_addr = 0;
+
+       mopt->mp_fail = 0;
+       mopt->mp_fclose = 0;
+}
+
+static inline void mptcp_reset_mopt(struct tcp_sock *tp)
+{
+       struct mptcp_options_received *mopt = &tp->mptcp->rx_opt;
+
+       mopt->saw_low_prio = 0;
+       mopt->saw_add_addr = 0;
+       mopt->more_add_addr = 0;
+       mopt->saw_rem_addr = 0;
+       mopt->more_rem_addr = 0;
+       mopt->join_ack = 0;
+       mopt->mp_fail = 0;
+       mopt->mp_fclose = 0;
+}
+
+static inline __be32 mptcp_get_highorder_sndbits(const struct sk_buff *skb,
+                                                const struct mptcp_cb *mpcb)
+{
+       return htonl(mpcb->snd_high_order[(TCP_SKB_CB(skb)->mptcp_flags &
+                       MPTCPHDR_SEQ64_INDEX) ? 1 : 0]);
+}
+
+static inline u64 mptcp_get_data_seq_64(const struct mptcp_cb *mpcb, int index,
+                                       u32 data_seq_32)
+{
+       return ((u64)mpcb->rcv_high_order[index] << 32) | data_seq_32;
+}
+
+static inline u64 mptcp_get_rcv_nxt_64(const struct tcp_sock *meta_tp)
+{
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       return mptcp_get_data_seq_64(mpcb, mpcb->rcv_hiseq_index,
+                                    meta_tp->rcv_nxt);
+}
+
+static inline void mptcp_check_sndseq_wrap(struct tcp_sock *meta_tp, int inc)
+{
+       if (unlikely(meta_tp->snd_nxt > meta_tp->snd_nxt + inc)) {
+               struct mptcp_cb *mpcb = meta_tp->mpcb;
+               mpcb->snd_hiseq_index = mpcb->snd_hiseq_index ? 0 : 1;
+               mpcb->snd_high_order[mpcb->snd_hiseq_index] += 2;
+       }
+}
+
+static inline void mptcp_check_rcvseq_wrap(struct tcp_sock *meta_tp,
+                                          u32 old_rcv_nxt)
+{
+       if (unlikely(old_rcv_nxt > meta_tp->rcv_nxt)) {
+               struct mptcp_cb *mpcb = meta_tp->mpcb;
+               mpcb->rcv_high_order[mpcb->rcv_hiseq_index] += 2;
+               mpcb->rcv_hiseq_index = mpcb->rcv_hiseq_index ? 0 : 1;
+       }
+}
+
+static inline int mptcp_sk_can_send(const struct sock *sk)
+{
+       return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
+              !tcp_sk(sk)->mptcp->pre_established;
+}
+
+static inline int mptcp_sk_can_recv(const struct sock *sk)
+{
+       return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCP_FIN_WAIT1 | TCP_FIN_WAIT2);
+}
+
+static inline int mptcp_sk_can_send_ack(const struct sock *sk)
+{
+       return !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV |
+                                       TCPF_CLOSE | TCPF_LISTEN)) &&
+              !tcp_sk(sk)->mptcp->pre_established;
+}
+
+/* Only support GSO if all subflows supports it */
+static inline bool mptcp_sk_can_gso(const struct sock *meta_sk)
+{
+       struct sock *sk;
+
+       if (tcp_sk(meta_sk)->mpcb->dss_csum)
+               return 0;
+
+       mptcp_for_each_sk(tcp_sk(meta_sk)->mpcb, sk) {
+               if (!mptcp_sk_can_send(sk))
+                       continue;
+               if (!sk_can_gso(sk))
+                       return false;
+       }
+       return true;
+}
+
+static inline bool mptcp_can_sg(const struct sock *meta_sk)
+{
+       struct sock *sk;
+
+       if (tcp_sk(meta_sk)->mpcb->dss_csum)
+               return 0;
+
+       mptcp_for_each_sk(tcp_sk(meta_sk)->mpcb, sk) {
+               if (!mptcp_sk_can_send(sk))
+                       continue;
+               if (!(sk->sk_route_caps & NETIF_F_SG))
+                       return false;
+       }
+       return true;
+}
+
+static inline void mptcp_set_rto(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *sk_it;
+       struct inet_connection_sock *micsk = inet_csk(mptcp_meta_sk(sk));
+       __u32 max_rto = 0;
+
+       /* We are in recovery-phase on the MPTCP-level. Do not update the
+        * RTO, because this would kill exponential backoff.
+        */
+       if (micsk->icsk_retransmits)
+               return;
+
+       mptcp_for_each_sk(tp->mpcb, sk_it) {
+               if (mptcp_sk_can_send(sk_it) &&
+                   inet_csk(sk_it)->icsk_rto > max_rto)
+                       max_rto = inet_csk(sk_it)->icsk_rto;
+       }
+       if (max_rto) {
+               micsk->icsk_rto = max_rto << 1;
+
+               /* A successfull rto-measurement - reset backoff counter */
+               micsk->icsk_backoff = 0;
+       }
+}
+
+static inline int mptcp_sysctl_syn_retries(void)
+{
+       return sysctl_mptcp_syn_retries;
+}
+
+static inline void mptcp_sub_close_passive(struct sock *sk)
+{
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct tcp_sock *tp = tcp_sk(sk), *meta_tp = tcp_sk(meta_sk);
+
+       /* Only close, if the app did a send-shutdown (passive close), and we
+        * received the data-ack of the data-fin.
+        */
+       if (tp->mpcb->passive_close && meta_tp->snd_una == meta_tp->write_seq)
+               mptcp_sub_close(sk, 0);
+}
+
+static inline bool mptcp_fallback_infinite(struct sock *sk, int flag)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       /* If data has been acknowleged on the meta-level, fully_established
+        * will have been set before and thus we will not fall back to infinite
+        * mapping.
+        */
+       if (likely(tp->mptcp->fully_established))
+               return false;
+
+       if (!(flag & MPTCP_FLAG_DATA_ACKED))
+               return false;
+
+       /* Don't fallback twice ;) */
+       if (tp->mpcb->infinite_mapping_snd)
+               return false;
+
+       pr_err("%s %#x will fallback - pi %d, src %pI4 dst %pI4 from %pS\n",
+              __func__, tp->mpcb->mptcp_loc_token, tp->mptcp->path_index,
+              &inet_sk(sk)->inet_saddr, &inet_sk(sk)->inet_daddr,
+              __builtin_return_address(0));
+       if (!is_master_tp(tp))
+               return true;
+
+       tp->mpcb->infinite_mapping_snd = 1;
+       tp->mpcb->infinite_mapping_rcv = 1;
+       tp->mptcp->fully_established = 1;
+
+       return false;
+}
+
+/* Find the first free index in the bitfield */
+static inline int __mptcp_find_free_index(u8 bitfield, int j, u8 base)
+{
+       int i;
+       mptcp_for_each_bit_unset(bitfield >> base, i) {
+               /* We wrapped at the bitfield - try from 0 on */
+               if (i + base >= sizeof(bitfield) * 8) {
+                       mptcp_for_each_bit_unset(bitfield, i) {
+                               if (i >= sizeof(bitfield) * 8)
+                                       goto exit;
+
+                               if (i != j)
+                                       return i;
+                       }
+                       goto exit;
+               }
+               if (i + base >= sizeof(bitfield) * 8)
+                       break;
+
+               if (i + base != j)
+                       return i + base;
+       }
+exit:
+       return -1;
+}
+
+static inline int mptcp_find_free_index(u8 bitfield)
+{
+       return __mptcp_find_free_index(bitfield, -1, 0);
+}
+
+/* Find the first index whose bit in the bit-field == 0 */
+static inline u8 mptcp_set_new_pathindex(struct mptcp_cb *mpcb)
+{
+       u8 base = mpcb->next_path_index;
+       int i;
+
+       /* Start at 1, because 0 is reserved for the meta-sk */
+       mptcp_for_each_bit_unset(mpcb->path_index_bits >> base, i) {
+               if (i + base < 1)
+                       continue;
+               if (i + base >= sizeof(mpcb->path_index_bits) * 8)
+                       break;
+               i += base;
+               mpcb->path_index_bits |= (1 << i);
+               mpcb->next_path_index = i + 1;
+               return i;
+       }
+       mptcp_for_each_bit_unset(mpcb->path_index_bits, i) {
+               if (i >= sizeof(mpcb->path_index_bits) * 8)
+                       break;
+               if (i < 1)
+                       continue;
+               mpcb->path_index_bits |= (1 << i);
+               mpcb->next_path_index = i + 1;
+               return i;
+       }
+
+       return 0;
+}
+
+static inline int mptcp_v6_is_v4_mapped(struct sock *sk)
+{
+       return sk->sk_family == AF_INET6 &&
+              ipv6_addr_type(&inet6_sk(sk)->saddr) == IPV6_ADDR_MAPPED;
+}
+
+/* TCP and MPTCP mpc flag-depending functions */
+u16 mptcp_select_window(struct sock *sk);
+void mptcp_init_buffer_space(struct sock *sk);
+void mptcp_tcp_set_rto(struct sock *sk);
+
+static inline void set_mpc(struct tcp_sock *tp)
+{
+       tp->mpc = 1;
+
+       tp->__select_window             = __mptcp_select_window;
+       tp->select_window               = mptcp_select_window;
+       tp->select_initial_window       = mptcp_select_initial_window;
+       tp->init_buffer_space           = mptcp_init_buffer_space;
+       tp->set_rto                     = mptcp_tcp_set_rto;
+       tp->should_expand_sndbuf        = mptcp_should_expand_sndbuf;
+}
+
+#else /* CONFIG_MPTCP */
+#define mptcp_debug(fmt, args...)      \
+       do {                            \
+       } while (0)
+
+/* Without MPTCP, we just do one iteration
+ * over the only socket available. This assumes that
+ * the sk/tp arg is the socket in that case.
+ */
+#define mptcp_for_each_sk(mpcb, sk)
+#define mptcp_for_each_sk_safe(__mpcb, __sk, __temp)
+
+static inline int mptcp_is_data_fin(const struct sk_buff *skb)
+{
+       return 0;
+}
+static inline int mptcp_is_data_seq(const struct sk_buff *skb)
+{
+       return 0;
+}
+static inline struct sock *mptcp_meta_sk(const struct sock *sk)
+{
+       return NULL;
+}
+static inline struct tcp_sock *mptcp_meta_tp(const struct tcp_sock *tp)
+{
+       return NULL;
+}
+static inline int is_meta_sk(const struct sock *sk)
+{
+       return 0;
+}
+static inline int is_master_tp(const struct tcp_sock *tp)
+{
+       return 0;
+}
+static inline void mptcp_purge_ofo_queue(struct tcp_sock *meta_tp) {}
+static inline void mptcp_cleanup_rbuf(const struct sock *meta_sk, int copied) {}
+static inline void mptcp_del_sock(const struct sock *sk) {}
+static inline void mptcp_reinject_data(struct sock *orig_sk, int clone_it) {}
+static inline void mptcp_update_sndbuf(const struct mptcp_cb *mpcb) {}
+static inline void mptcp_skb_entail_init(const struct tcp_sock *tp,
+                                        const struct sk_buff *skb) {}
+static inline void mptcp_clean_rtx_infinite(const struct sk_buff *skb,
+                                           const struct sock *sk) {}
+static inline void mptcp_retransmit_timer(const struct sock *meta_sk) {}
+static inline int mptcp_write_wakeup(struct sock *meta_sk)
+{
+       return 0;
+}
+static inline void mptcp_sub_close(struct sock *sk, unsigned long delay) {}
+static inline void mptcp_set_rto(const struct sock *sk) {}
+static inline void mptcp_send_fin(const struct sock *meta_sk) {}
+static inline void mptcp_parse_options(const uint8_t *ptr, const int opsize,
+                                      const struct tcp_options_received *opt_rx,
+                                      const struct mptcp_options_received *mopt,
+                                      const struct sk_buff *skb) {}
+static inline void mptcp_syn_options(struct sock *sk,
+                                    struct tcp_out_options *opts,
+                                    unsigned *remaining) {}
+static inline void mptcp_synack_options(struct request_sock *req,
+                                       struct tcp_out_options *opts,
+                                       unsigned *remaining) {}
+
+static inline void mptcp_established_options(struct sock *sk,
+                                            struct sk_buff *skb,
+                                            struct tcp_out_options *opts,
+                                            unsigned *size) {}
+static inline void mptcp_options_write(__be32 *ptr, struct tcp_sock *tp,
+                                      struct tcp_out_options *opts,
+                                      struct sk_buff *skb) {}
+static inline void mptcp_close(struct sock *meta_sk, long timeout) {}
+static inline int mptcp_doit(struct sock *sk)
+{
+       return 0;
+}
+static inline int mptcp_check_req_master(const struct sock *sk,
+                                        const struct sock *child,
+                                        struct request_sock *req,
+                                        struct request_sock **prev,
+                                        const struct mptcp_options_received *mopt)
+{
+       return 1;
+}
+static inline struct sock *mptcp_check_req_child(struct sock *sk,
+                                                struct sock *child,
+                                                struct request_sock *req,
+                                                struct request_sock **prev,
+                                                struct mptcp_options_received *mopt)
+{
+       return NULL;
+}
+static inline unsigned int mptcp_current_mss(struct sock *meta_sk)
+{
+       return 0;
+}
+static inline int mptcp_select_size(const struct sock *meta_sk, bool sg)
+{
+       return 0;
+}
+static inline void mptcp_sub_close_passive(struct sock *sk) {}
+static inline bool mptcp_fallback_infinite(const struct sock *sk, int flag)
+{
+       return false;
+}
+static inline void mptcp_init_mp_opt(const struct mptcp_options_received *mopt) {}
+static inline int mptcp_check_rtt(const struct tcp_sock *tp, int time)
+{
+       return 0;
+}
+static inline int mptcp_check_snd_buf(const struct tcp_sock *tp)
+{
+       return 0;
+}
+static inline int mptcp_sysctl_syn_retries(void)
+{
+       return 0;
+}
+static inline void mptcp_send_reset(const struct sock *sk) {}
+static inline void mptcp_send_active_reset(struct sock *meta_sk,
+                                          gfp_t priority) {}
+static inline int mptcp_write_xmit(struct sock *sk, unsigned int mss_now,
+                                  int nonagle, int push_one, gfp_t gfp)
+{
+       return 0;
+}
+static inline struct sock *mptcp_sk_clone(const struct sock *sk, int family,
+                                         const gfp_t priority)
+{
+       return NULL;
+}
+static inline int mptcp_handle_options(struct sock *sk,
+                                      const struct tcphdr *th,
+                                      struct sk_buff *skb)
+{
+       return 0;
+}
+static inline void mptcp_reset_mopt(struct tcp_sock *tp) {}
+static inline void  __init mptcp_init(void) {}
+static inline int mptcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
+{
+       return 0;
+}
+static inline int mptcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
+                                unsigned int mss_now, int reinject)
+{
+       return 0;
+}
+static inline int mptso_fragment(struct sock *sk, struct sk_buff *skb,
+                                unsigned int len, unsigned int mss_now,
+                                gfp_t gfp, int reinject)
+{
+       return 0;
+}
+static inline bool mptcp_sk_can_gso(const struct sock *sk)
+{
+       return false;
+}
+static inline bool mptcp_can_sg(const struct sock *meta_sk)
+{
+       return false;
+}
+static inline unsigned int mptcp_xmit_size_goal(struct sock *meta_sk,
+                                               u32 mss_now, int large_allowed)
+{
+       return 0;
+}
+static inline void mptcp_destroy_sock(struct sock *sk) {}
+static inline int mptcp_rcv_synsent_state_process(struct sock *sk,
+                                                 struct sock **skptr,
+                                                 struct sk_buff *skb,
+                                                 struct mptcp_options_received *mopt)
+{
+       return 0;
+}
+static inline bool mptcp_can_sendpage(struct sock *sk)
+{
+       return false;
+}
+static inline int mptcp_time_wait(struct sock *sk, struct tcp_timewait_sock *tw)
+{
+       return 0;
+}
+static inline void mptcp_twsk_destructor(struct tcp_timewait_sock *tw) {}
+static inline void mptcp_update_tw_socks(const struct tcp_sock *tp, int state) {}
+static inline void mptcp_disconnect(struct sock *sk) {}
+static inline void mptcp_tsq_flags(struct sock *sk) {}
+static inline void mptcp_tsq_sub_deferred(struct sock *meta_sk) {}
+static inline void mptcp_hash_remove_bh(struct tcp_sock *meta_tp) {}
+static inline void mptcp_hash_remove(struct tcp_sock *meta_tp) {}
+static inline void mptcp_reqsk_new_mptcp(struct request_sock *req,
+                                        const struct tcp_options_received *rx_opt,
+                                        const struct mptcp_options_received *mopt,
+                                        const struct sk_buff *skb) {}
+static inline void mptcp_remove_shortcuts(const struct mptcp_cb *mpcb,
+                                         const struct sk_buff *skb) {}
+#endif /* CONFIG_MPTCP */
+
+#endif /* _MPTCP_H */
diff -Nur linux-3.14.45.orig/include/net/mptcp_v4.h linux-3.14.45/include/net/mptcp_v4.h
--- linux-3.14.45.orig/include/net/mptcp_v4.h   1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/include/net/mptcp_v4.h        2015-06-24 14:15:48.871862463 +0200
@@ -0,0 +1,69 @@
+/*
+ *     MPTCP implementation
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef MPTCP_V4_H_
+#define MPTCP_V4_H_
+
+
+#include <linux/in.h>
+#include <linux/skbuff.h>
+#include <net/mptcp.h>
+#include <net/request_sock.h>
+#include <net/sock.h>
+
+extern struct request_sock_ops mptcp_request_sock_ops;
+
+#ifdef CONFIG_MPTCP
+
+int mptcp_v4_do_rcv(struct sock *meta_sk, struct sk_buff *skb);
+int mptcp_v4_rem_raddress(struct mptcp_cb *mpcb, u8 id);
+int mptcp_v4_add_raddress(struct mptcp_cb *mpcb, const struct in_addr *addr,
+                         __be16 port, u8 id);
+void mptcp_v4_set_init_addr_bit(struct mptcp_cb *mpcb, __be32 daddr, int index);
+struct sock *mptcp_v4_search_req(const __be16 rport, const __be32 raddr,
+                                const __be32 laddr, const struct net *net);
+int mptcp_init4_subsockets(struct sock *meta_sk, const struct mptcp_loc4 *loc,
+                          struct mptcp_rem4 *rem);
+int mptcp_pm_v4_init(void);
+void mptcp_pm_v4_undo(void);
+u32 mptcp_v4_get_nonce(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
+                      u32 seq);
+u64 mptcp_v4_get_key(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport);
+
+#else
+
+static inline int mptcp_v4_do_rcv(const struct sock *meta_sk,
+                                 const struct sk_buff *skb)
+{
+       return 0;
+}
+
+#endif /* CONFIG_MPTCP */
+
+#endif /* MPTCP_V4_H_ */
diff -Nur linux-3.14.45.orig/include/net/mptcp_v6.h linux-3.14.45/include/net/mptcp_v6.h
--- linux-3.14.45.orig/include/net/mptcp_v6.h   1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/include/net/mptcp_v6.h        2015-06-24 14:15:48.871862463 +0200
@@ -0,0 +1,72 @@
+/*
+ *     MPTCP implementation
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _MPTCP_V6_H
+#define _MPTCP_V6_H
+
+#include <linux/in6.h>
+#include <net/if_inet6.h>
+
+#include <net/mptcp.h>
+
+extern struct request_sock_ops mptcp6_request_sock_ops;
+extern struct proto mptcpv6_prot;
+
+#ifdef CONFIG_MPTCP
+
+int mptcp_v6_do_rcv(struct sock *meta_sk, struct sk_buff *skb);
+int mptcp_v6_rem_raddress(struct mptcp_cb *mpcb, u8 id);
+int mptcp_v6_add_raddress(struct mptcp_cb *mpcb, const struct in6_addr *addr,
+                         __be16 port, u8 id);
+void mptcp_v6_set_init_addr_bit(struct mptcp_cb *mpcb,
+                               const struct in6_addr *daddr, int index);
+struct sock *mptcp_v6_search_req(const __be16 rport, const struct in6_addr *raddr,
+                                const struct in6_addr *laddr, const struct net *net);
+int mptcp_init6_subsockets(struct sock *meta_sk, const struct mptcp_loc6 *loc,
+                          struct mptcp_rem6 *rem);
+int mptcp_pm_v6_init(void);
+void mptcp_pm_v6_undo(void);
+struct sock *mptcp_v6v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
+                                     struct request_sock *req,
+                                     struct dst_entry *dst);
+__u32 mptcp_v6_get_nonce(const __be32 *saddr, const __be32 *daddr,
+                        __be16 sport, __be16 dport, u32 seq);
+u64 mptcp_v6_get_key(const __be32 *saddr, const __be32 *daddr,
+                    __be16 sport, __be16 dport);
+
+#else /* CONFIG_MPTCP */
+
+static inline int mptcp_v6_do_rcv(struct sock *meta_sk, struct sk_buff *skb)
+{
+       return 0;
+}
+
+#endif /* CONFIG_MPTCP */
+
+#endif /* _MPTCP_V6_H */
diff -Nur linux-3.14.45.orig/include/net/net_namespace.h linux-3.14.45/include/net/net_namespace.h
--- linux-3.14.45.orig/include/net/net_namespace.h      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/net/net_namespace.h   2015-06-24 14:15:48.871862463 +0200
@@ -15,6 +15,7 @@
 #include <net/netns/packet.h>
 #include <net/netns/ipv4.h>
 #include <net/netns/ipv6.h>
+#include <net/netns/mptcp.h>
 #include <net/netns/sctp.h>
 #include <net/netns/dccp.h>
 #include <net/netns/netfilter.h>
@@ -90,6 +91,9 @@
 #if IS_ENABLED(CONFIG_IPV6)
        struct netns_ipv6       ipv6;
 #endif
+#if IS_ENABLED(CONFIG_MPTCP)
+       struct netns_mptcp      mptcp;
+#endif
 #if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
        struct netns_sctp       sctp;
 #endif
diff -Nur linux-3.14.45.orig/include/net/netns/mptcp.h linux-3.14.45/include/net/netns/mptcp.h
--- linux-3.14.45.orig/include/net/netns/mptcp.h        1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/include/net/netns/mptcp.h     2015-06-24 14:15:48.871862463 +0200
@@ -0,0 +1,44 @@
+/*
+ *     MPTCP implementation - MPTCP namespace
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef __NETNS_MPTCP_H__
+#define __NETNS_MPTCP_H__
+
+#include <linux/compiler.h>
+
+enum {
+       MPTCP_PM_FULLMESH = 0,
+       MPTCP_PM_MAX
+};
+
+struct netns_mptcp {
+       void *path_managers[MPTCP_PM_MAX];
+};
+
+#endif /* __NETNS_MPTCP_H__ */
diff -Nur linux-3.14.45.orig/include/net/request_sock.h linux-3.14.45/include/net/request_sock.h
--- linux-3.14.45.orig/include/net/request_sock.h       2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/net/request_sock.h    2015-06-24 14:15:48.871862463 +0200
@@ -164,7 +164,7 @@
 };
 
 int reqsk_queue_alloc(struct request_sock_queue *queue,
-                     unsigned int nr_table_entries);
+                     unsigned int nr_table_entries, gfp_t flags);
 
 void __reqsk_queue_destroy(struct request_sock_queue *queue);
 void reqsk_queue_destroy(struct request_sock_queue *queue);
diff -Nur linux-3.14.45.orig/include/net/sock.h linux-3.14.45/include/net/sock.h
--- linux-3.14.45.orig/include/net/sock.h       2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/net/sock.h    2015-06-24 14:15:48.871862463 +0200
@@ -899,6 +899,16 @@
 
 int sk_wait_data(struct sock *sk, long *timeo);
 
+/* START - needed for MPTCP */
+extern void sock_def_error_report(struct sock *sk);
+extern struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
+                                 int family);
+extern void sock_lock_init(struct sock *sk);
+
+extern struct lock_class_key af_callback_keys[AF_MAX];
+extern char *const af_family_clock_key_strings[AF_MAX+1];
+/* END - needed for MPTCP */
+
 struct request_sock_ops;
 struct timewait_sock_ops;
 struct inet_hashinfo;
diff -Nur linux-3.14.45.orig/include/net/tcp.h linux-3.14.45/include/net/tcp.h
--- linux-3.14.45.orig/include/net/tcp.h        2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/net/tcp.h     2015-06-24 14:15:48.875862469 +0200
@@ -176,6 +176,7 @@
 #define TCPOPT_SACK             5       /* SACK Block */
 #define TCPOPT_TIMESTAMP       8       /* Better RTT estimations/PAWS */
 #define TCPOPT_MD5SIG          19      /* MD5 Signature (RFC2385) */
+#define TCPOPT_MPTCP           30
 #define TCPOPT_EXP             254     /* Experimental */
 /* Magic number to be after the option value for sharing TCP
  * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
@@ -234,6 +235,27 @@
  */
 #define        TFO_SERVER_ALWAYS       0x1000
 
+/* Flags from tcp_input.c for tcp_ack */
+#define FLAG_DATA               0x01 /* Incoming frame contained data.          */
+#define FLAG_WIN_UPDATE         0x02 /* Incoming ACK was a window update.       */
+#define FLAG_DATA_ACKED         0x04 /* This ACK acknowledged new data.         */
+#define FLAG_RETRANS_DATA_ACKED 0x08 /* "" "" some of which was retransmitted.  */
+#define FLAG_SYN_ACKED          0x10 /* This ACK acknowledged SYN.              */
+#define FLAG_DATA_SACKED        0x20 /* New SACK.                               */
+#define FLAG_ECE                0x40 /* ECE in this ACK                         */
+#define FLAG_SLOWPATH           0x100 /* Do not skip RFC checks for window update.*/
+#define FLAG_ORIG_SACK_ACKED    0x200 /* Never retransmitted data are (s)acked  */
+#define FLAG_SND_UNA_ADVANCED   0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */
+#define FLAG_DSACKING_ACK       0x800 /* SACK blocks contained D-SACK info */
+#define FLAG_SACK_RENEGING      0x2000 /* snd_una advanced to a sacked seq */
+#define FLAG_UPDATE_TS_RECENT   0x4000 /* tcp_replace_ts_recent() */
+#define MPTCP_FLAG_DATA_ACKED  0x8000
+
+#define FLAG_ACKED              (FLAG_DATA_ACKED|FLAG_SYN_ACKED)
+#define FLAG_NOT_DUP            (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
+#define FLAG_CA_ALERT           (FLAG_DATA_SACKED|FLAG_ECE)
+#define FLAG_FORWARD_PROGRESS   (FLAG_ACKED|FLAG_DATA_SACKED)
+
 extern struct inet_timewait_death_row tcp_death_row;
 
 /* sysctl variables for tcp */
@@ -349,6 +371,112 @@
 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
 #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
 
+/**** START - Exports needed for MPTCP ****/
+extern const struct inet_connection_sock_af_ops ipv4_specific;
+extern const struct inet_connection_sock_af_ops ipv6_specific;
+extern const struct inet_connection_sock_af_ops ipv6_mapped;
+extern const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops;
+extern const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops;
+
+struct mptcp_options_received;
+
+int tcp_close_state(struct sock *sk);
+void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, int
+             size_goal);
+void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss_now,
+                        const struct sk_buff *skb);
+int tcp_xmit_probe_skb(struct sock *sk, int urgent);
+void tcp_cwnd_validate(struct sock *sk);
+void tcp_event_new_data_sent(struct sock *sk, const struct sk_buff *skb);
+int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
+                    gfp_t gfp_mask);
+unsigned int tcp_mss_split_point(const struct sock *sk,
+                                const struct sk_buff *skb,
+                                unsigned int mss_now,
+                                unsigned int max_segs,
+                                int nonagle);
+bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb);
+bool tcp_nagle_test(const struct tcp_sock *tp, const struct sk_buff *skb,
+                   unsigned int cur_mss, int nonagle);
+bool tcp_snd_wnd_test(const struct tcp_sock *tp, const struct sk_buff *skb,
+                     unsigned int cur_mss);
+unsigned int tcp_cwnd_test(const struct tcp_sock *tp, const struct sk_buff *skb);
+int tcp_mtu_probe(struct sock *sk);
+int tcp_init_tso_segs(const struct sock *sk, struct sk_buff *skb,
+                     unsigned int mss_now);
+void __pskb_trim_head(struct sk_buff *skb, int len);
+void tcp_queue_skb(struct sock *sk, struct sk_buff *skb);
+void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags);
+void tcp_reset(struct sock *sk);
+bool tcp_may_update_window(const struct tcp_sock *tp, const u32 ack,
+                          const u32 ack_seq, const u32 nwin);
+bool tcp_urg_mode(const struct tcp_sock *tp);
+void tcp_ack_probe(struct sock *sk);
+void tcp_rearm_rto(struct sock *sk);
+int tcp_write_timeout(struct sock *sk);
+bool retransmits_timed_out(struct sock *sk, unsigned int boundary,
+                          unsigned int timeout, bool syn_set);
+void tcp_write_err(struct sock *sk);
+void tcp_adjust_pcount(struct sock *sk, const struct sk_buff *skb, int decr);
+void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
+                         unsigned int mss_now);
+
+int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req);
+void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+                          struct request_sock *req);
+__u32 tcp_v4_init_sequence(const struct sk_buff *skb);
+int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
+                      struct request_sock *req,
+                      u16 queue_mapping);
+void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb);
+struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb);
+struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb);
+void tcp_v4_reqsk_destructor(struct request_sock *req);
+
+int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req);
+void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+                          struct request_sock *req);
+__u32 tcp_v6_init_sequence(const struct sk_buff *skb);
+int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
+                      struct flowi6 *fl6, struct request_sock *req,
+                      u16 queue_mapping);
+void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
+int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
+int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
+void tcp_v6_destroy_sock(struct sock *sk);
+void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb);
+void tcp_v6_hash(struct sock *sk);
+struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb);
+struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
+                                 struct request_sock *req,
+                                 struct dst_entry *dst);
+void tcp_v6_reqsk_destructor(struct request_sock *req);
+
+void sock_valbool_flag(struct sock *sk, int bit, int valbool);
+unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
+                                      int large_allowed);
+u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb);
+
+void skb_clone_fraglist(struct sk_buff *skb);
+void copy_skb_header(struct sk_buff *new, const struct sk_buff *old);
+
+void inet_twsk_free(struct inet_timewait_sock *tw);
+/* These states need RST on ABORT according to RFC793 */
+static inline bool tcp_need_reset(int state)
+{
+       return (1 << state) &
+              (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
+               TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
+}
+
+bool tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb,
+                           int hlen);
+int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int hdrlen,
+                              bool *fragstolen);
+bool tcp_try_coalesce(struct sock *sk, struct sk_buff *to,
+                     struct sk_buff *from, bool *fragstolen);
+/**** END - Exports needed for MPTCP ****/
+
 void tcp_tasklet_init(void);
 
 void tcp_v4_err(struct sk_buff *skb, u32);
@@ -445,6 +573,7 @@
                size_t len, int nonblock, int flags, int *addr_len);
 void tcp_parse_options(const struct sk_buff *skb,
                       struct tcp_options_received *opt_rx,
+                      struct mptcp_options_received *mopt_rx,
                       int estab, struct tcp_fastopen_cookie *foc);
 const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
 
@@ -558,11 +687,15 @@
 void tcp_send_loss_probe(struct sock *sk);
 bool tcp_schedule_loss_probe(struct sock *sk);
 
+u16 tcp_select_window(struct sock *sk);
+
 /* tcp_input.c */
 void tcp_cwnd_application_limited(struct sock *sk);
 void tcp_resume_early_retransmit(struct sock *sk);
 void tcp_rearm_rto(struct sock *sk);
 void tcp_reset(struct sock *sk);
+void tcp_set_rto(struct sock *sk);
+bool tcp_should_expand_sndbuf(const struct sock *sk);
 
 /* tcp_timer.c */
 void tcp_init_xmit_timers(struct sock *);
@@ -706,14 +839,24 @@
  */
 struct tcp_skb_cb {
        union {
-               struct inet_skb_parm    h4;
+               union {
+                       struct inet_skb_parm    h4;
 #if IS_ENABLED(CONFIG_IPV6)
-               struct inet6_skb_parm   h6;
+                       struct inet6_skb_parm   h6;
+#endif
+               } header;       /* For incoming frames          */
+#ifdef CONFIG_MPTCP
+               __u32 path_mask; /* path indices that tried to send this skb */
 #endif
-       } header;       /* For incoming frames          */
+       };
        __u32           seq;            /* Starting sequence number     */
        __u32           end_seq;        /* SEQ + FIN + SYN + datalen    */
        __u32           when;           /* used to compute rtt's        */
+#ifdef CONFIG_MPTCP
+       __u8            mptcp_flags;    /* flags for the MPTCP layer    */
+       __u8            dss_off;        /* Number of 4-byte words until
+                                        * seq-number */
+#endif
        __u8            tcp_flags;      /* TCP header flags. (tcp[13])  */
 
        __u8            sacked;         /* State flags for SACK/FACK.   */
@@ -1061,7 +1204,8 @@
 /* Determine a window scaling and initial window to offer. */
 void tcp_select_initial_window(int __space, __u32 mss, __u32 *rcv_wnd,
                               __u32 *window_clamp, int wscale_ok,
-                              __u8 *rcv_wscale, __u32 init_rcv_wnd);
+                              __u8 *rcv_wscale, __u32 init_rcv_wnd,
+                              const struct sock *sk);
 
 static inline int tcp_win_from_space(int space)
 {
@@ -1073,12 +1217,18 @@
 /* Note: caller must be prepared to deal with negative returns */ 
 static inline int tcp_space(const struct sock *sk)
 {
+       if (tcp_sk(sk)->mpc)
+               sk = tcp_sk(sk)->meta_sk;
+
        return tcp_win_from_space(sk->sk_rcvbuf -
                                  atomic_read(&sk->sk_rmem_alloc));
 } 
 
 static inline int tcp_full_space(const struct sock *sk)
 {
+       if (tcp_sk(sk)->mpc)
+               sk = tcp_sk(sk)->meta_sk;
+
        return tcp_win_from_space(sk->sk_rcvbuf); 
 }
 
@@ -1093,6 +1243,7 @@
        tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
        tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
        tcp_rsk(req)->snt_synack = 0;
+       tcp_rsk(req)->saw_mpc = 0;
        req->mss = rx_opt->mss_clamp;
        req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
        ireq->tstamp_ok = rx_opt->tstamp_ok;
diff -Nur linux-3.14.45.orig/include/uapi/linux/if.h linux-3.14.45/include/uapi/linux/if.h
--- linux-3.14.45.orig/include/uapi/linux/if.h  2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/uapi/linux/if.h       2015-06-24 14:15:48.875862469 +0200
@@ -53,6 +53,9 @@
 
 #define IFF_ECHO       0x40000         /* echo sent packets            */
 
+#define IFF_NOMULTIPATH        0x80000         /* Disable for MPTCP            */
+#define IFF_MPBACKUP   0x100000        /* Use as backup path for MPTCP */
+
 #define IFF_VOLATILE   (IFF_LOOPBACK|IFF_POINTOPOINT|IFF_BROADCAST|IFF_ECHO|\
                IFF_MASTER|IFF_SLAVE|IFF_RUNNING|IFF_LOWER_UP|IFF_DORMANT)
 
diff -Nur linux-3.14.45.orig/include/uapi/linux/tcp.h linux-3.14.45/include/uapi/linux/tcp.h
--- linux-3.14.45.orig/include/uapi/linux/tcp.h 2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/include/uapi/linux/tcp.h      2015-06-24 14:15:48.875862469 +0200
@@ -112,6 +112,7 @@
 #define TCP_FASTOPEN           23      /* Enable FastOpen on listeners */
 #define TCP_TIMESTAMP          24
 #define TCP_NOTSENT_LOWAT      25      /* limit number of unsent bytes in write queue */
+#define MPTCP_ENABLED          26
 
 struct tcp_repair_opt {
        __u32   opt_code;
diff -Nur linux-3.14.45.orig/net/Kconfig linux-3.14.45/net/Kconfig
--- linux-3.14.45.orig/net/Kconfig      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/Kconfig   2015-06-24 14:15:48.875862469 +0200
@@ -79,6 +79,7 @@
 source "net/ipv4/Kconfig"
 source "net/ipv6/Kconfig"
 source "net/netlabel/Kconfig"
+source "net/mptcp/Kconfig"
 
 endif # if INET
 
diff -Nur linux-3.14.45.orig/net/Makefile linux-3.14.45/net/Makefile
--- linux-3.14.45.orig/net/Makefile     2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/Makefile  2015-06-24 14:15:48.875862469 +0200
@@ -20,6 +20,7 @@
 obj-$(CONFIG_XFRM)             += xfrm/
 obj-$(CONFIG_UNIX)             += unix/
 obj-$(CONFIG_NET)              += ipv6/
+obj-$(CONFIG_MPTCP)            += mptcp/
 obj-$(CONFIG_PACKET)           += packet/
 obj-$(CONFIG_NET_KEY)          += key/
 obj-$(CONFIG_BRIDGE)           += bridge/
diff -Nur linux-3.14.45.orig/net/core/dev.c linux-3.14.45/net/core/dev.c
--- linux-3.14.45.orig/net/core/dev.c   2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/core/dev.c        2015-06-24 14:15:48.875862469 +0200
@@ -5399,7 +5399,7 @@
 
        dev->flags = (flags & (IFF_DEBUG | IFF_NOTRAILERS | IFF_NOARP |
                               IFF_DYNAMIC | IFF_MULTICAST | IFF_PORTSEL |
-                              IFF_AUTOMEDIA)) |
+                              IFF_AUTOMEDIA | IFF_NOMULTIPATH | IFF_MPBACKUP)) |
                     (dev->flags & (IFF_UP | IFF_VOLATILE | IFF_PROMISC |
                                    IFF_ALLMULTI));
 
diff -Nur linux-3.14.45.orig/net/core/request_sock.c linux-3.14.45/net/core/request_sock.c
--- linux-3.14.45.orig/net/core/request_sock.c  2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/core/request_sock.c       2015-06-24 14:15:48.875862469 +0200
@@ -38,7 +38,8 @@
 EXPORT_SYMBOL(sysctl_max_syn_backlog);
 
 int reqsk_queue_alloc(struct request_sock_queue *queue,
-                     unsigned int nr_table_entries)
+                     unsigned int nr_table_entries,
+                     gfp_t flags)
 {
        size_t lopt_size = sizeof(struct listen_sock);
        struct listen_sock *lopt;
@@ -48,9 +49,11 @@
        nr_table_entries = roundup_pow_of_two(nr_table_entries + 1);
        lopt_size += nr_table_entries * sizeof(struct request_sock *);
        if (lopt_size > PAGE_SIZE)
-               lopt = vzalloc(lopt_size);
+               lopt = __vmalloc(lopt_size,
+                       flags | __GFP_HIGHMEM | __GFP_ZERO,
+                       PAGE_KERNEL);
        else
-               lopt = kzalloc(lopt_size, GFP_KERNEL);
+               lopt = kzalloc(lopt_size, flags);
        if (lopt == NULL)
                return -ENOMEM;
 
diff -Nur linux-3.14.45.orig/net/core/skbuff.c linux-3.14.45/net/core/skbuff.c
--- linux-3.14.45.orig/net/core/skbuff.c        2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/core/skbuff.c     2015-06-24 14:15:48.875862469 +0200
@@ -491,7 +491,7 @@
        skb_drop_list(&skb_shinfo(skb)->frag_list);
 }
 
-static void skb_clone_fraglist(struct sk_buff *skb)
+void skb_clone_fraglist(struct sk_buff *skb)
 {
        struct sk_buff *list;
 
@@ -913,7 +913,7 @@
        skb->inner_mac_header += off;
 }
 
-static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
+void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 {
        __copy_skb_header(new, old);
 
diff -Nur linux-3.14.45.orig/net/core/sock.c linux-3.14.45/net/core/sock.c
--- linux-3.14.45.orig/net/core/sock.c  2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/core/sock.c       2015-06-24 14:15:48.875862469 +0200
@@ -280,7 +280,7 @@
   "slock-AF_IEEE802154", "slock-AF_CAIF" , "slock-AF_ALG"      ,
   "slock-AF_NFC"   , "slock-AF_VSOCK"    ,"slock-AF_MAX"
 };
-static const char *const af_family_clock_key_strings[AF_MAX+1] = {
+char *const af_family_clock_key_strings[AF_MAX+1] = {
   "clock-AF_UNSPEC", "clock-AF_UNIX"     , "clock-AF_INET"     ,
   "clock-AF_AX25"  , "clock-AF_IPX"      , "clock-AF_APPLETALK",
   "clock-AF_NETROM", "clock-AF_BRIDGE"   , "clock-AF_ATMPVC"   ,
@@ -301,7 +301,7 @@
  * sk_callback_lock locking rules are per-address-family,
  * so split the lock classes by using a per-AF key:
  */
-static struct lock_class_key af_callback_keys[AF_MAX];
+struct lock_class_key af_callback_keys[AF_MAX];
 
 /* Take into consideration the size of the struct sk_buff overhead in the
  * determination of these values, since that is non-constant across
@@ -651,7 +651,7 @@
        return ret;
 }
 
-static inline void sock_valbool_flag(struct sock *sk, int bit, int valbool)
+void sock_valbool_flag(struct sock *sk, int bit, int valbool)
 {
        if (valbool)
                sock_set_flag(sk, bit);
@@ -1272,7 +1272,7 @@
  *
  * (We also register the sk_lock with the lock validator.)
  */
-static inline void sock_lock_init(struct sock *sk)
+void sock_lock_init(struct sock *sk)
 {
        sock_lock_init_class_and_name(sk,
                        af_family_slock_key_strings[sk->sk_family],
@@ -1320,7 +1320,7 @@
 }
 EXPORT_SYMBOL(sk_prot_clear_portaddr_nulls);
 
-static struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
+struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
                int family)
 {
        struct sock *sk;
@@ -2252,7 +2252,7 @@
        rcu_read_unlock();
 }
 
-static void sock_def_error_report(struct sock *sk)
+void sock_def_error_report(struct sock *sk)
 {
        struct socket_wq *wq;
 
diff -Nur linux-3.14.45.orig/net/ipv4/Kconfig linux-3.14.45/net/ipv4/Kconfig
--- linux-3.14.45.orig/net/ipv4/Kconfig 2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/Kconfig      2015-06-24 14:15:48.875862469 +0200
@@ -556,6 +556,30 @@
        For further details see:
          http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
 
+config TCP_CONG_COUPLED
+       tristate "MPTCP COUPLED CONGESTION CONTROL"
+       depends on MPTCP
+       default n
+       ---help---
+       MultiPath TCP Coupled Congestion Control
+       To enable it, just put 'coupled' in tcp_congestion_control
+
+config TCP_CONG_OLIA
+       tristate "MPTCP Opportunistic Linked Increase"
+       depends on MPTCP
+       default n
+       ---help---
+       MultiPath TCP Opportunistic Linked Increase Congestion Control
+       To enable it, just put 'olia' in tcp_congestion_control
+
+config TCP_CONG_WVEGAS
+       tristate "MPTCP WVEGAS CONGESTION CONTROL"
+       depends on MPTCP
+       default n
+       ---help---
+       wVegas congestion control for MPTCP
+       To enable it, just put 'wvegas' in tcp_congestion_control
+
 choice
        prompt "Default TCP congestion control"
        default DEFAULT_CUBIC
@@ -584,6 +608,15 @@
        config DEFAULT_WESTWOOD
                bool "Westwood" if TCP_CONG_WESTWOOD=y
 
+       config DEFAULT_COUPLED
+               bool "Coupled" if TCP_CONG_COUPLED=y
+
+       config DEFAULT_OLIA
+               bool "Olia" if TCP_CONG_OLIA=y
+
+       config DEFAULT_WVEGAS
+               bool "Wvegas" if TCP_CONG_WVEGAS=y
+
        config DEFAULT_RENO
                bool "Reno"
 
@@ -605,6 +638,8 @@
        default "vegas" if DEFAULT_VEGAS
        default "westwood" if DEFAULT_WESTWOOD
        default "veno" if DEFAULT_VENO
+       default "coupled" if DEFAULT_COUPLED
+       default "wvegas" if DEFAULT_WVEGAS
        default "reno" if DEFAULT_RENO
        default "cubic"
 
diff -Nur linux-3.14.45.orig/net/ipv4/af_inet.c linux-3.14.45/net/ipv4/af_inet.c
--- linux-3.14.45.orig/net/ipv4/af_inet.c       2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/af_inet.c    2015-06-24 14:15:48.875862469 +0200
@@ -104,6 +104,7 @@
 #include <net/ip_fib.h>
 #include <net/inet_connection_sock.h>
 #include <net/tcp.h>
+#include <net/mptcp.h>
 #include <net/udp.h>
 #include <net/udplite.h>
 #include <net/ping.h>
@@ -246,8 +247,7 @@
  *     Create an inet socket.
  */
 
-static int inet_create(struct net *net, struct socket *sock, int protocol,
-                      int kern)
+int inet_create(struct net *net, struct socket *sock, int protocol, int kern)
 {
        struct sock *sk;
        struct inet_protosw *answer;
@@ -679,6 +679,23 @@
        lock_sock(sk2);
 
        sock_rps_record_flow(sk2);
+
+       if (sk2->sk_protocol == IPPROTO_TCP && tcp_sk(sk2)->mpc) {
+               struct sock *sk_it = sk2;
+
+               mptcp_for_each_sk(tcp_sk(sk2)->mpcb, sk_it)
+                       sock_rps_record_flow(sk_it);
+
+               if (tcp_sk(sk2)->mpcb->master_sk) {
+                       sk_it = tcp_sk(sk2)->mpcb->master_sk;
+
+                       write_lock_bh(&sk_it->sk_callback_lock);
+                       sk_it->sk_wq = newsock->wq;
+                       sk_it->sk_socket = newsock;
+                       write_unlock_bh(&sk_it->sk_callback_lock);
+               }
+       }
+
        WARN_ON(!((1 << sk2->sk_state) &
                  (TCPF_ESTABLISHED | TCPF_SYN_RECV |
                  TCPF_CLOSE_WAIT | TCPF_CLOSE)));
@@ -1770,6 +1787,9 @@
 
        ip_init();
 
+       /* We must initialize MPTCP before TCP. */
+       mptcp_init();
+
        tcp_v4_init();
 
        /* Setup TCP slab cache for open requests. */
diff -Nur linux-3.14.45.orig/net/ipv4/inet_connection_sock.c linux-3.14.45/net/ipv4/inet_connection_sock.c
--- linux-3.14.45.orig/net/ipv4/inet_connection_sock.c  2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/inet_connection_sock.c       2015-06-24 14:15:48.875862469 +0200
@@ -23,6 +23,7 @@
 #include <net/route.h>
 #include <net/tcp_states.h>
 #include <net/xfrm.h>
+#include <net/mptcp.h>
 
 #ifdef INET_CSK_DEBUG
 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
@@ -468,8 +469,8 @@
 }
 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);
 
-static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
-                                const u32 rnd, const u32 synq_hsize)
+u32 inet_synq_hash(const __be32 raddr, const __be16 rport, const u32 rnd,
+                  const u32 synq_hsize)
 {
        return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
 }
@@ -667,7 +668,12 @@
                                 const struct request_sock *req,
                                 const gfp_t priority)
 {
-       struct sock *newsk = sk_clone_lock(sk, priority);
+       struct sock *newsk;
+
+       if (sk->sk_protocol == IPPROTO_TCP && tcp_sk(sk)->mpc)
+               newsk = mptcp_sk_clone(sk, req->rsk_ops->family, priority);
+       else
+               newsk = sk_clone_lock(sk, priority);
 
        if (newsk != NULL) {
                struct inet_connection_sock *newicsk = inet_csk(newsk);
@@ -744,7 +750,8 @@
 {
        struct inet_sock *inet = inet_sk(sk);
        struct inet_connection_sock *icsk = inet_csk(sk);
-       int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);
+       int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries,
+                                  GFP_KERNEL);
 
        if (rc != 0)
                return rc;
@@ -802,9 +809,14 @@
 
        while ((req = acc_req) != NULL) {
                struct sock *child = req->sk;
+               bool mutex_taken = false;
 
                acc_req = req->dl_next;
 
+               if (is_meta_sk(child)) {
+                       mutex_lock(&tcp_sk(child)->mpcb->mpcb_mutex);
+                       mutex_taken = true;
+               }
                local_bh_disable();
                bh_lock_sock(child);
                WARN_ON(sock_owned_by_user(child));
@@ -833,6 +845,8 @@
 
                bh_unlock_sock(child);
                local_bh_enable();
+               if (mutex_taken)
+                       mutex_unlock(&tcp_sk(child)->mpcb->mpcb_mutex);
                sock_put(child);
 
                sk_acceptq_removed(sk);
diff -Nur linux-3.14.45.orig/net/ipv4/syncookies.c linux-3.14.45/net/ipv4/syncookies.c
--- linux-3.14.45.orig/net/ipv4/syncookies.c    2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/syncookies.c 2015-06-24 14:15:48.875862469 +0200
@@ -284,7 +284,7 @@
 
        /* check for timestamp cookie support */
        memset(&tcp_opt, 0, sizeof(tcp_opt));
-       tcp_parse_options(skb, &tcp_opt, 0, NULL);
+       tcp_parse_options(skb, &tcp_opt, NULL, 0, NULL);
 
        if (!cookie_check_timestamp(&tcp_opt, sock_net(sk), &ecn_ok))
                goto out;
@@ -354,10 +354,10 @@
        /* Try to redo what tcp_v4_send_synack did. */
        req->window_clamp = tp->window_clamp ? :dst_metric(&rt->dst, RTAX_WINDOW);
 
-       tcp_select_initial_window(tcp_full_space(sk), req->mss,
+       tp->select_initial_window(tcp_full_space(sk), req->mss,
                                  &req->rcv_wnd, &req->window_clamp,
                                  ireq->wscale_ok, &rcv_wscale,
-                                 dst_metric(&rt->dst, RTAX_INITRWND));
+                                 dst_metric(&rt->dst, RTAX_INITRWND), sk);
 
        ireq->rcv_wscale  = rcv_wscale;
 
diff -Nur linux-3.14.45.orig/net/ipv4/tcp.c linux-3.14.45/net/ipv4/tcp.c
--- linux-3.14.45.orig/net/ipv4/tcp.c   2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/tcp.c        2015-06-24 14:15:48.879862472 +0200
@@ -271,6 +271,7 @@
 
 #include <net/icmp.h>
 #include <net/inet_common.h>
+#include <net/mptcp.h>
 #include <net/tcp.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
@@ -419,6 +420,9 @@
        sk->sk_sndbuf = sysctl_tcp_wmem[1];
        sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 
+       /* Set function pointers in tcp_sock to tcp functions. */
+       mptcp_init_tcp_sock(tp);
+
        local_bh_disable();
        sock_update_memcg(sk);
        sk_sockets_allocated_inc(sk);
@@ -607,6 +611,8 @@
        tcb->seq     = tcb->end_seq = tp->write_seq;
        tcb->tcp_flags = TCPHDR_ACK;
        tcb->sacked  = 0;
+       if (tp->mpc)
+               mptcp_skb_entail_init(tp, skb);
        skb_header_release(skb);
        tcp_add_write_queue_tail(sk, skb);
        sk->sk_wmem_queued += skb->truesize;
@@ -640,8 +646,8 @@
               atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
 }
 
-static void tcp_push(struct sock *sk, int flags, int mss_now,
-                    int nonagle, int size_goal)
+void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle,
+             int size_goal)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *skb;
@@ -726,6 +732,14 @@
        int ret;
 
        sock_rps_record_flow(sk);
+
+#ifdef CONFIG_MPTCP
+       if (tcp_sk(sk)->mpc) {
+               struct sock *sk_it;
+               mptcp_for_each_sk(tcp_sk(sk)->mpcb, sk_it)
+                       sock_rps_record_flow(sk_it);
+       }
+#endif
        /*
         * We can't seek on a socket input
         */
@@ -821,8 +835,7 @@
        return NULL;
 }
 
-static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
-                                      int large_allowed)
+unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, int large_allowed)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        u32 xmit_size_goal, old_size_goal;
@@ -872,8 +885,13 @@
 {
        int mss_now;
 
-       mss_now = tcp_current_mss(sk);
-       *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
+       if (tcp_sk(sk)->mpc) {
+               mss_now = mptcp_current_mss(sk);
+               *size_goal = mptcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
+       } else {
+               mss_now = tcp_current_mss(sk);
+               *size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
+       }
 
        return mss_now;
 }
@@ -897,6 +915,26 @@
                        goto out_err;
        }
 
+       if (tp->mpc) {
+               struct sock *sk_it = sk;
+
+               /* We must check this with socket-lock hold because we iterate
+                * over the subflows.
+                */
+               if (!mptcp_can_sendpage(sk)) {
+                       ssize_t ret;
+
+                       release_sock(sk);
+                       ret = sock_no_sendpage(sk->sk_socket, page, offset,
+                                              size, flags);
+                       lock_sock(sk);
+                       return ret;
+               }
+
+               mptcp_for_each_sk(tp->mpcb, sk_it)
+                       sock_rps_record_flow(sk_it);
+       }
+
        clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 
        mss_now = tcp_send_mss(sk, &size_goal, flags);
@@ -1001,8 +1039,9 @@
 {
        ssize_t res;
 
-       if (!(sk->sk_route_caps & NETIF_F_SG) ||
-           !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
+       /* If MPTCP is enabled, we check it later after establishment */
+       if (!tcp_sk(sk)->mpc && (!(sk->sk_route_caps & NETIF_F_SG) ||
+           !(sk->sk_route_caps & NETIF_F_ALL_CSUM)))
                return sock_no_sendpage(sk->sk_socket, page, offset, size,
                                        flags);
 
@@ -1018,6 +1057,9 @@
        const struct tcp_sock *tp = tcp_sk(sk);
        int tmp = tp->mss_cache;
 
+       if (tp->mpc)
+               return mptcp_select_size(sk, sg);
+
        if (sg) {
                if (sk_can_gso(sk)) {
                        /* Small frames wont use a full page:
@@ -1105,6 +1147,12 @@
                        goto do_error;
        }
 
+       if (tp->mpc) {
+               struct sock *sk_it = sk;
+               mptcp_for_each_sk(tp->mpcb, sk_it)
+                       sock_rps_record_flow(sk_it);
+       }
+
        if (unlikely(tp->repair)) {
                if (tp->repair_queue == TCP_RECV_QUEUE) {
                        copied = tcp_send_rcvq(sk, msg, size);
@@ -1132,7 +1180,10 @@
        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
                goto out_err;
 
-       sg = !!(sk->sk_route_caps & NETIF_F_SG);
+       if (tp->mpc)
+               sg = mptcp_can_sg(sk);
+       else
+               sg = !!(sk->sk_route_caps & NETIF_F_SG);
 
        while (--iovlen >= 0) {
                size_t seglen = iov->iov_len;
@@ -1176,8 +1227,15 @@
 
                                /*
                                 * Check whether we can use HW checksum.
+                                *
+                                * If dss-csum is enabled, we do not do hw-csum.
+                                * In case of non-mptcp we check the
+                                * device-capabilities.
+                                * In case of mptcp, hw-csum's will be handled
+                                * later in mptcp_write_xmit.
                                 */
-                               if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
+                               if (((tp->mpc && !tp->mpcb->dss_csum) || !tp->mpc) &&
+                                   (tp->mpc || sk->sk_route_caps & NETIF_F_ALL_CSUM))
                                        skb->ip_summed = CHECKSUM_PARTIAL;
 
                                skb_entail(sk, skb);
@@ -1386,6 +1444,11 @@
 
        struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
 
+       if (is_meta_sk(sk)) {
+               mptcp_cleanup_rbuf(sk, copied);
+               return;
+       }
+
        WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
             "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
             tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
@@ -1422,7 +1485,7 @@
 
                /* Optimize, __tcp_select_window() is not cheap. */
                if (2*rcv_window_now <= tp->window_clamp) {
-                       __u32 new_window = __tcp_select_window(sk);
+                       __u32 new_window = tp->__select_window(sk);
 
                        /* Send ACK now, if this read freed lots of space
                         * in our buffer. Certainly, new_window is new window.
@@ -1623,6 +1686,14 @@
 
        lock_sock(sk);
 
+#ifdef CONFIG_MPTCP
+       if (tp->mpc) {
+               struct sock *sk_it;
+               mptcp_for_each_sk(tp->mpcb, sk_it)
+                       sock_rps_record_flow(sk_it);
+       }
+#endif
+
        err = -ENOTCONN;
        if (sk->sk_state == TCP_LISTEN)
                goto out;
@@ -2070,7 +2141,7 @@
   /* TCP_CLOSING       */ TCP_CLOSING,
 };
 
-static int tcp_close_state(struct sock *sk)
+int tcp_close_state(struct sock *sk)
 {
        int next = (int)new_state[sk->sk_state];
        int ns = next & TCP_STATE_MASK;
@@ -2099,8 +2170,12 @@
            (TCPF_ESTABLISHED | TCPF_SYN_SENT |
             TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
                /* Clear out any half completed packets.  FIN if needed. */
-               if (tcp_close_state(sk))
-                       tcp_send_fin(sk);
+               if (tcp_close_state(sk)) {
+                       if (!is_meta_sk(sk))
+                               tcp_send_fin(sk);
+                       else
+                               mptcp_send_fin(sk);
+               }
        }
 }
 EXPORT_SYMBOL(tcp_shutdown);
@@ -2125,6 +2200,11 @@
        int data_was_unread = 0;
        int state;
 
+       if (is_meta_sk(sk)) {
+               mptcp_close(sk, timeout);
+               return;
+       }
+
        lock_sock(sk);
        sk->sk_shutdown = SHUTDOWN_MASK;
 
@@ -2291,15 +2371,6 @@
 }
 EXPORT_SYMBOL(tcp_close);
 
-/* These states need RST on ABORT according to RFC793 */
-
-static inline bool tcp_need_reset(int state)
-{
-       return (1 << state) &
-              (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
-               TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
-}
-
 int tcp_disconnect(struct sock *sk, int flags)
 {
        struct inet_sock *inet = inet_sk(sk);
@@ -2340,6 +2411,13 @@
        if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
                inet_reset_saddr(sk);
 
+       if (is_meta_sk(sk)) {
+               mptcp_disconnect(sk);
+       } else {
+               if (tp->inside_tk_table)
+                       mptcp_hash_remove_bh(tp);
+       }
+
        sk->sk_shutdown = 0;
        sock_reset_flag(sk, SOCK_DONE);
        tp->srtt = 0;
@@ -2699,6 +2777,18 @@
                tp->notsent_lowat = val;
                sk->sk_write_space(sk);
                break;
+#ifdef CONFIG_MPTCP
+       case MPTCP_ENABLED:
+               if (sk->sk_state == TCP_CLOSE || sk->sk_state == TCP_LISTEN) {
+                       if (val)
+                               tp->mptcp_enabled = 1;
+                       else
+                               tp->mptcp_enabled = 0;
+               } else {
+                       err = -EPERM;
+               }
+               break;
+#endif
        default:
                err = -ENOPROTOOPT;
                break;
@@ -2918,6 +3008,11 @@
        case TCP_NOTSENT_LOWAT:
                val = tp->notsent_lowat;
                break;
+#ifdef CONFIG_MPTCP
+       case MPTCP_ENABLED:
+               val = tp->mptcp_enabled;
+               break;
+#endif
        default:
                return -ENOPROTOOPT;
        }
@@ -3088,8 +3183,11 @@
        if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
                TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
 
+       WARN_ON(sk->sk_state == TCP_CLOSE);
        tcp_set_state(sk, TCP_CLOSE);
+
        tcp_clear_xmit_timers(sk);
+
        if (req != NULL)
                reqsk_fastopen_remove(sk, req, false);
 
diff -Nur linux-3.14.45.orig/net/ipv4/tcp_input.c linux-3.14.45/net/ipv4/tcp_input.c
--- linux-3.14.45.orig/net/ipv4/tcp_input.c     2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/tcp_input.c  2015-06-24 14:15:48.883862476 +0200
@@ -74,6 +74,9 @@
 #include <linux/ipsec.h>
 #include <asm/unaligned.h>
 #include <net/netdma.h>
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+#include <net/mptcp_v6.h>
 
 int sysctl_tcp_timestamps __read_mostly = 1;
 int sysctl_tcp_window_scaling __read_mostly = 1;
@@ -99,25 +102,6 @@
 int sysctl_tcp_moderate_rcvbuf __read_mostly = 1;
 int sysctl_tcp_early_retrans __read_mostly = 3;
 
-#define FLAG_DATA              0x01 /* Incoming frame contained data.          */
-#define FLAG_WIN_UPDATE                0x02 /* Incoming ACK was a window update.       */
-#define FLAG_DATA_ACKED                0x04 /* This ACK acknowledged new data.         */
-#define FLAG_RETRANS_DATA_ACKED        0x08 /* "" "" some of which was retransmitted.  */
-#define FLAG_SYN_ACKED         0x10 /* This ACK acknowledged SYN.              */
-#define FLAG_DATA_SACKED       0x20 /* New SACK.                               */
-#define FLAG_ECE               0x40 /* ECE in this ACK                         */
-#define FLAG_SLOWPATH          0x100 /* Do not skip RFC checks for window update.*/
-#define FLAG_ORIG_SACK_ACKED   0x200 /* Never retransmitted data are (s)acked  */
-#define FLAG_SND_UNA_ADVANCED  0x400 /* Snd_una was changed (!= FLAG_DATA_ACKED) */
-#define FLAG_DSACKING_ACK      0x800 /* SACK blocks contained D-SACK info */
-#define FLAG_SACK_RENEGING     0x2000 /* snd_una advanced to a sacked seq */
-#define FLAG_UPDATE_TS_RECENT  0x4000 /* tcp_replace_ts_recent() */
-
-#define FLAG_ACKED             (FLAG_DATA_ACKED|FLAG_SYN_ACKED)
-#define FLAG_NOT_DUP           (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
-#define FLAG_CA_ALERT          (FLAG_DATA_SACKED|FLAG_ECE)
-#define FLAG_FORWARD_PROGRESS  (FLAG_ACKED|FLAG_DATA_SACKED)
-
 #define TCP_REMNANT (TCP_FLAG_FIN|TCP_FLAG_URG|TCP_FLAG_SYN|TCP_FLAG_PSH)
 #define TCP_HP_BITS (~(TCP_RESERVED_BITS|TCP_FLAG_PSH))
 
@@ -283,8 +267,12 @@
        per_mss = roundup_pow_of_two(per_mss) +
                  SKB_DATA_ALIGN(sizeof(struct sk_buff));
 
-       nr_segs = max_t(u32, TCP_INIT_CWND, tp->snd_cwnd);
-       nr_segs = max_t(u32, nr_segs, tp->reordering + 1);
+       if (tp->mpc) {
+               nr_segs = mptcp_check_snd_buf(tp);
+       } else {
+               nr_segs = max_t(u32, TCP_INIT_CWND, tp->snd_cwnd);
+               nr_segs = max_t(u32, nr_segs, tp->reordering + 1);
+       }
 
        /* Fast Recovery (RFC 5681 3.2) :
         * Cubic needs 1.7 factor, rounded to 2 to include
@@ -292,8 +280,16 @@
         */
        sndmem = 2 * nr_segs * per_mss;
 
-       if (sk->sk_sndbuf < sndmem)
+       /* MPTCP: after this sndmem is the new contribution of the
+        * current subflow to the aggregated sndbuf */
+       if (sk->sk_sndbuf < sndmem) {
+               int old_sndbuf = sk->sk_sndbuf;
                sk->sk_sndbuf = min(sndmem, sysctl_tcp_wmem[2]);
+               /* MPTCP: ok, the subflow sndbuf has grown, reflect
+                * this in the aggregate buffer.*/
+               if (tp->mpc && old_sndbuf != sk->sk_sndbuf)
+                       mptcp_update_sndbuf(tp->mpcb);
+       }
 }
 
 /* 2. Tuning advertised window (window_clamp, rcv_ssthresh)
@@ -342,10 +338,12 @@
 static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb)
 {
        struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
 
        /* Check #1 */
-       if (tp->rcv_ssthresh < tp->window_clamp &&
-           (int)tp->rcv_ssthresh < tcp_space(sk) &&
+       if (meta_tp->rcv_ssthresh < meta_tp->window_clamp &&
+           (int)meta_tp->rcv_ssthresh < tcp_space(sk) &&
            !sk_under_memory_pressure(sk)) {
                int incr;
 
@@ -353,14 +351,14 @@
                 * will fit to rcvbuf in future.
                 */
                if (tcp_win_from_space(skb->truesize) <= skb->len)
-                       incr = 2 * tp->advmss;
+                       incr = 2 * meta_tp->advmss;
                else
-                       incr = __tcp_grow_window(sk, skb);
+                       incr = __tcp_grow_window(meta_sk, skb);
 
                if (incr) {
                        incr = max_t(int, incr, 2 * skb->len);
-                       tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr,
-                                              tp->window_clamp);
+                       meta_tp->rcv_ssthresh = min(meta_tp->rcv_ssthresh + incr,
+                                                   meta_tp->window_clamp);
                        inet_csk(sk)->icsk_ack.quick |= 1;
                }
        }
@@ -543,7 +541,10 @@
        int copied;
 
        time = tcp_time_stamp - tp->rcvq_space.time;
-       if (time < (tp->rcv_rtt_est.rtt >> 3) || tp->rcv_rtt_est.rtt == 0)
+       if (tp->mpc) {
+               if (mptcp_check_rtt(tp, time))
+                       return;
+       } else if (time < (tp->rcv_rtt_est.rtt >> 3) || tp->rcv_rtt_est.rtt == 0)
                return;
 
        /* Number of bytes copied to user in last RTT */
@@ -768,7 +769,7 @@
 /* Calculate rto without backoff.  This is the second half of Van Jacobson's
  * routine referred to above.
  */
-static void tcp_set_rto(struct sock *sk)
+void tcp_set_rto(struct sock *sk)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
        /* Old crap is replaced with new one. 8)
@@ -2909,7 +2910,7 @@
                return false;
 
        tcp_rtt_estimator(sk, seq_rtt);
-       tcp_set_rto(sk);
+       tp->set_rto(sk);
 
        /* RFC6298: only reset backoff on valid RTT measurement. */
        inet_csk(sk)->icsk_backoff = 0;
@@ -2993,7 +2994,7 @@
 }
 
 /* If we get here, the whole TSO packet has not been acked. */
-static u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb)
+u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        u32 packets_acked;
@@ -3088,6 +3089,8 @@
                 */
                if (!(scb->tcp_flags & TCPHDR_SYN)) {
                        flag |= FLAG_DATA_ACKED;
+                       if (tp->mpc && mptcp_is_data_seq(skb))
+                               flag |= MPTCP_FLAG_DATA_ACKED;
                } else {
                        flag |= FLAG_SYN_ACKED;
                        tp->retrans_stamp = 0;
@@ -3190,7 +3193,7 @@
        return flag;
 }
 
-static void tcp_ack_probe(struct sock *sk)
+void tcp_ack_probe(struct sock *sk)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
        struct inet_connection_sock *icsk = inet_csk(sk);
@@ -3237,9 +3240,8 @@
 /* Check that window update is acceptable.
  * The function assumes that snd_una<=ack<=snd_next.
  */
-static inline bool tcp_may_update_window(const struct tcp_sock *tp,
-                                       const u32 ack, const u32 ack_seq,
-                                       const u32 nwin)
+bool tcp_may_update_window(const struct tcp_sock *tp, const u32 ack,
+                          const u32 ack_seq, const u32 nwin)
 {
        return  after(ack, tp->snd_una) ||
                after(ack_seq, tp->snd_wl1) ||
@@ -3358,7 +3360,7 @@
 }
 
 /* This routine deals with incoming acks, but not outgoing ones. */
-static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
+static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
@@ -3453,6 +3455,16 @@
        flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una, sack_rtt);
        acked -= tp->packets_out;
 
+       if (tp->mpc) {
+               if (mptcp_fallback_infinite(sk, flag)) {
+                       pr_err("%s resetting flow\n", __func__);
+                       mptcp_send_reset(sk);
+                       goto invalid_ack;
+               }
+
+               mptcp_clean_rtx_infinite(skb, sk);
+       }
+
        /* Advance cwnd if state allows */
        if (tcp_may_raise_cwnd(sk, flag))
                tcp_cong_avoid(sk, ack, acked, prior_in_flight);
@@ -3517,8 +3529,9 @@
  * the fast version below fails.
  */
 void tcp_parse_options(const struct sk_buff *skb,
-                      struct tcp_options_received *opt_rx, int estab,
-                      struct tcp_fastopen_cookie *foc)
+                      struct tcp_options_received *opt_rx,
+                      struct mptcp_options_received *mopt,
+                      int estab, struct tcp_fastopen_cookie *foc)
 {
        const unsigned char *ptr;
        const struct tcphdr *th = tcp_hdr(skb);
@@ -3601,6 +3614,10 @@
                                 */
                                break;
 #endif
+                       case TCPOPT_MPTCP:
+                               mptcp_parse_options(ptr - 2, opsize, opt_rx,
+                                                   mopt, skb);
+                               break;
                        case TCPOPT_EXP:
                                /* Fast Open option shares code 254 using a
                                 * 16 bits magic number. It's valid only in
@@ -3662,8 +3679,8 @@
                if (tcp_parse_aligned_timestamp(tp, th))
                        return true;
        }
-
-       tcp_parse_options(skb, &tp->rx_opt, 1, NULL);
+       tcp_parse_options(skb, &tp->rx_opt, tp->mpc ? &tp->mptcp->rx_opt : NULL,
+                         1, NULL);
        if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
                tp->rx_opt.rcv_tsecr -= tp->tsoffset;
 
@@ -3836,6 +3853,8 @@
                dst = __sk_dst_get(sk);
                if (!dst || !dst_metric(dst, RTAX_QUICKACK))
                        inet_csk(sk)->icsk_ack.pingpong = 1;
+               if (tp->mpc)
+                       mptcp_sub_close_passive(sk);
                break;
 
        case TCP_CLOSE_WAIT:
@@ -3857,6 +3876,13 @@
                tcp_set_state(sk, TCP_CLOSING);
                break;
        case TCP_FIN_WAIT2:
+               if (tp->mpc) {
+                       /* The socket will get closed by mptcp_data_ready.
+                        * We first have to process all data-sequences.
+                        */
+                       tp->close_it = 1;
+                       break;
+               }
                /* Received a FIN -- send ACK and enter TIME_WAIT. */
                tcp_send_ack(sk);
                tcp_time_wait(sk, TCP_TIME_WAIT, 0);
@@ -3881,6 +3907,10 @@
        if (!sock_flag(sk, SOCK_DEAD)) {
                sk->sk_state_change(sk);
 
+               /* Don't wake up MPTCP-subflows */
+               if (tp->mpc)
+                       return;
+
                /* Do not send POLL_HUP for half duplex close. */
                if (sk->sk_shutdown == SHUTDOWN_MASK ||
                    sk->sk_state == TCP_CLOSE)
@@ -4078,7 +4108,11 @@
                        tcp_dsack_extend(sk, TCP_SKB_CB(skb)->seq, dsack);
                }
 
-               if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
+               /* In case of MPTCP, the segment may be empty if it's a
+                * non-data DATA_FIN. (see beginning of tcp_data_queue)
+                */
+               if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt) &&
+                   !(tp->mpc && TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq)) {
                        SOCK_DEBUG(sk, "ofo packet was already received\n");
                        __skb_unlink(skb, &tp->out_of_order_queue);
                        __kfree_skb(skb);
@@ -4102,6 +4136,9 @@
 static int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb,
                                 unsigned int size)
 {
+       if (tcp_sk(sk)->mpc)
+               sk = mptcp_meta_sk(sk);
+
        if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
            !sk_rmem_schedule(sk, skb, size)) {
 
@@ -4132,15 +4169,16 @@
  * Better try to coalesce them right now to avoid future collapses.
  * Returns true if caller should free @from instead of queueing it
  */
-static bool tcp_try_coalesce(struct sock *sk,
-                            struct sk_buff *to,
-                            struct sk_buff *from,
-                            bool *fragstolen)
+bool tcp_try_coalesce(struct sock *sk, struct sk_buff *to, struct sk_buff *from,
+                     bool *fragstolen)
 {
        int delta;
 
        *fragstolen = false;
 
+       if (tcp_sk(sk)->mpc && !is_meta_sk(sk))
+               return false;
+
        if (tcp_hdr(from)->fin)
                return false;
 
@@ -4230,7 +4268,9 @@
 
        /* Do skb overlap to previous one? */
        if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) {
-               if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
+               /* MPTCP allows non-data data-fin to be in the ofo-queue */
+               if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq) &&
+                   !(tp->mpc && end_seq == seq)) {
                        /* All the bits are present. Drop. */
                        NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPOFOMERGE);
                        __kfree_skb(skb);
@@ -4268,6 +4308,9 @@
                                         end_seq);
                        break;
                }
+               /* MPTCP allows non-data data-fin to be in the ofo-queue */
+               if (tp->mpc && TCP_SKB_CB(skb1)->seq == TCP_SKB_CB(skb1)->end_seq)
+                       continue;
                __skb_unlink(skb1, &tp->out_of_order_queue);
                tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
                                 TCP_SKB_CB(skb1)->end_seq);
@@ -4285,8 +4328,8 @@
        }
 }
 
-static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int hdrlen,
-                 bool *fragstolen)
+int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int hdrlen,
+                              bool *fragstolen)
 {
        int eaten;
        struct sk_buff *tail = skb_peek_tail(&sk->sk_receive_queue);
@@ -4348,7 +4391,10 @@
        int eaten = -1;
        bool fragstolen = false;
 
-       if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq)
+       /* If no data is present, but a data_fin is in the options, we still
+        * have to call mptcp_queue_skb later on. */
+       if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq &&
+           !(tp->mpc && mptcp_is_data_fin(skb)))
                goto drop;
 
        skb_dst_drop(skb);
@@ -4394,7 +4440,7 @@
                        eaten = tcp_queue_rcv(sk, skb, 0, &fragstolen);
                }
                tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
-               if (skb->len)
+               if (skb->len || mptcp_is_data_fin(skb))
                        tcp_event_data_recv(sk, skb);
                if (th->fin)
                        tcp_fin(sk);
@@ -4416,7 +4462,11 @@
 
                if (eaten > 0)
                        kfree_skb_partial(skb, fragstolen);
-               if (!sock_flag(sk, SOCK_DEAD))
+               if (!sock_flag(sk, SOCK_DEAD) || tp->mpc)
+                       /* MPTCP: we always have to call data_ready, because
+                        * we may be about to receive a data-fin, which still
+                        * must get queued.
+                        */
                        sk->sk_data_ready(sk, 0);
                return;
        }
@@ -4468,6 +4518,8 @@
                next = skb_queue_next(list, skb);
 
        __skb_unlink(skb, list);
+       if (tcp_sk(sk)->mpc)
+               mptcp_remove_shortcuts(tcp_sk(sk)->mpcb, skb);
        __kfree_skb(skb);
        NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRCVCOLLAPSED);
 
@@ -4640,6 +4692,18 @@
        struct tcp_sock *tp = tcp_sk(sk);
        bool res = false;
 
+       if (is_meta_sk(sk)) {
+               if (!skb_queue_empty(&tp->out_of_order_queue)) {
+                       NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_OFOPRUNED);
+                       mptcp_purge_ofo_queue(tp);
+
+                       /* No sack at the mptcp-level */
+                       sk_mem_reclaim(sk);
+                       res = true;
+               }
+               return res;
+       }
+
        if (!skb_queue_empty(&tp->out_of_order_queue)) {
                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_OFOPRUNED);
                __skb_queue_purge(&tp->out_of_order_queue);
@@ -4729,7 +4793,7 @@
        tp->snd_cwnd_stamp = tcp_time_stamp;
 }
 
-static bool tcp_should_expand_sndbuf(const struct sock *sk)
+bool tcp_should_expand_sndbuf(const struct sock *sk)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
 
@@ -4764,7 +4828,7 @@
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
-       if (tcp_should_expand_sndbuf(sk)) {
+       if (tp->should_expand_sndbuf(sk)) {
                tcp_sndbuf_expand(sk);
                tp->snd_cwnd_stamp = tcp_time_stamp;
        }
@@ -4776,8 +4840,9 @@
 {
        if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) {
                sock_reset_flag(sk, SOCK_QUEUE_SHRUNK);
-               if (sk->sk_socket &&
-                   test_bit(SOCK_NOSPACE, &sk->sk_socket->flags))
+               if (tcp_sk(sk)->mpc ||
+                   (sk->sk_socket &&
+                       test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)))
                        tcp_new_space(sk);
        }
 }
@@ -4800,7 +4865,7 @@
             /* ... and right edge of window advances far enough.
              * (tcp_recvmsg() will send ACK otherwise). Or...
              */
-            __tcp_select_window(sk) >= tp->rcv_wnd) ||
+            tp->__select_window(sk) >= tp->rcv_wnd) ||
            /* We ACK each frame or... */
            tcp_in_quickack_mode(sk) ||
            /* We have out of order data. */
@@ -4902,6 +4967,10 @@
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
+       /* MPTCP urgent data is not yet supported */
+       if (tp->mpc)
+               return;
+
        /* Check if we get a new urgent pointer - normally not. */
        if (th->urg)
                tcp_check_urg(sk, th);
@@ -4969,8 +5038,7 @@
 }
 
 #ifdef CONFIG_NET_DMA
-static bool tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb,
-                                 int hlen)
+bool tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, int hlen)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        int chunk = skb->len - hlen;
@@ -5079,9 +5147,15 @@
                goto discard;
        }
 
+       /* If valid: post process the received MPTCP options. */
+       if (tp->mpc && mptcp_handle_options(sk, th, skb))
+               goto discard;
+
        return true;
 
 discard:
+       if (tp->mpc)
+               mptcp_reset_mopt(tp);
        __kfree_skb(skb);
        return false;
 }
@@ -5133,6 +5207,10 @@
 
        tp->rx_opt.saw_tstamp = 0;
 
+       /* MPTCP: force slowpath. */
+       if (tp->mpc)
+               goto slow_path;
+
        /*      pred_flags is 0xS?10 << 16 + snd_wnd
         *      if header_prediction is to be made
         *      'S' will always be tp->tcp_header_len >> 2
@@ -5347,7 +5425,7 @@
         */
        tp->lsndtime = tcp_time_stamp;
 
-       tcp_init_buffer_space(sk);
+       tp->init_buffer_space(sk);
 
        if (sock_flag(sk, SOCK_KEEPOPEN))
                inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp));
@@ -5377,7 +5455,7 @@
                /* Get original SYNACK MSS value if user MSS sets mss_clamp */
                tcp_clear_options(&opt);
                opt.user_mss = opt.mss_clamp = 0;
-               tcp_parse_options(synack, &opt, 0, NULL);
+               tcp_parse_options(synack, &opt, NULL, 0, NULL);
                mss = opt.mss_clamp;
        }
 
@@ -5412,8 +5490,11 @@
        struct tcp_sock *tp = tcp_sk(sk);
        struct tcp_fastopen_cookie foc = { .len = -1 };
        int saved_clamp = tp->rx_opt.mss_clamp;
+       struct mptcp_options_received mopt;
+       mptcp_init_mp_opt(&mopt);
 
-       tcp_parse_options(skb, &tp->rx_opt, 0, &foc);
+       tcp_parse_options(skb, &tp->rx_opt,
+                         tp->mpc ? &tp->mptcp->rx_opt : &mopt, 0, &foc);
        if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
                tp->rx_opt.rcv_tsecr -= tp->tsoffset;
 
@@ -5460,6 +5541,21 @@
                if (!th->syn)
                        goto discard_and_undo;
 
+               if (tp->request_mptcp || tp->mpc) {
+                       int ret;
+                       ret = mptcp_rcv_synsent_state_process(sk, &sk,
+                                                             skb, &mopt);
+
+                       /* May have changed if we support MPTCP */
+                       tp = tcp_sk(sk);
+                       icsk = inet_csk(sk);
+
+                       if (ret == 1)
+                               goto reset_and_undo;
+                       if (ret == 2)
+                               goto discard;
+               }
+
                /* rfc793:
                 *   "If the SYN bit is on ...
                 *    are acceptable then ...
@@ -5472,6 +5568,15 @@
                tcp_init_wl(tp, TCP_SKB_CB(skb)->seq);
                tcp_ack(sk, skb, FLAG_SLOWPATH);
 
+               if (tp->mpc && !is_master_tp(tp)) {
+                       /* Timer for repeating the ACK until an answer
+                        * arrives. Used only when establishing an additional
+                        * subflow inside of an MPTCP connection.
+                        */
+                       sk_reset_timer(sk, &tp->mptcp->mptcp_ack_timer,
+                                      jiffies + icsk->icsk_rto);
+               }
+
                /* Ok.. it's good. Set up sequence numbers and
                 * move to established.
                 */
@@ -5498,6 +5603,11 @@
                        tp->tcp_header_len = sizeof(struct tcphdr);
                }
 
+               if (tp->mpc) {
+                       tp->tcp_header_len += MPTCP_SUB_LEN_DSM_ALIGN;
+                       tp->advmss -= MPTCP_SUB_LEN_DSM_ALIGN;
+               }
+
                if (tcp_is_sack(tp) && sysctl_tcp_fack)
                        tcp_enable_fack(tp);
 
@@ -5518,7 +5628,9 @@
                    tcp_rcv_fastopen_synack(sk, skb, &foc))
                        return -1;
 
-               if (sk->sk_write_pending ||
+               /* With MPTCP we cannot send data on the third ack due to the
+                * lack of option-space */
+               if ((sk->sk_write_pending && !tp->mpc) ||
                    icsk->icsk_accept_queue.rskq_defer_accept ||
                    icsk->icsk_ack.pingpong) {
                        /* Save one ACK. Data will be ready after
@@ -5560,6 +5672,7 @@
            tcp_paws_reject(&tp->rx_opt, 0))
                goto discard_and_undo;
 
+       /* TODO - check this here for MPTCP */
        if (th->syn) {
                /* We see SYN without ACK. It is attempt of
                 * simultaneous connect with crossed SYNs.
@@ -5576,6 +5689,11 @@
                        tp->tcp_header_len = sizeof(struct tcphdr);
                }
 
+               if (tp->mpc) {
+                       tp->tcp_header_len += MPTCP_SUB_LEN_DSM_ALIGN;
+                       tp->advmss -= MPTCP_SUB_LEN_DSM_ALIGN;
+               }
+
                tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
                tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1;
 
@@ -5634,6 +5752,7 @@
 
 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                          const struct tcphdr *th, unsigned int len)
+       __releases(&sk->sk_lock.slock)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct inet_connection_sock *icsk = inet_csk(sk);
@@ -5685,6 +5804,10 @@
 
        case TCP_SYN_SENT:
                queued = tcp_rcv_synsent_state_process(sk, skb, th, len);
+               if (is_meta_sk(sk)) {
+                       sk = tcp_sk(sk)->mpcb->master_sk;
+                       tp = tcp_sk(sk);
+               }
                if (queued >= 0)
                        return queued;
 
@@ -5692,6 +5815,8 @@
                tcp_urg(sk, skb, th);
                __kfree_skb(skb);
                tcp_data_snd_check(sk);
+               if (tp->mpc && is_master_tp(tp))
+                       bh_unlock_sock(sk);
                return 0;
        }
 
@@ -5734,7 +5859,7 @@
 
                        tcp_mtup_init(sk);
                        tp->copied_seq = tp->rcv_nxt;
-                       tcp_init_buffer_space(sk);
+                       tp->init_buffer_space(sk);
                }
                smp_mb();
                tcp_set_state(sk, TCP_ESTABLISHED);
@@ -5754,6 +5879,8 @@
 
                if (tp->rx_opt.tstamp_ok)
                        tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
+               if (tp->mpc)
+                       tp->advmss -= MPTCP_SUB_LEN_DSM_ALIGN;
 
                if (req) {
                        /* Re-arm the timer because data may have been sent out.
@@ -5775,6 +5902,12 @@
 
                tcp_initialize_rcv_mss(sk);
                tcp_fast_path_on(tp);
+               /* Send an ACK when establishing a new
+                * MPTCP subflow, i.e. using an MP_JOIN
+                * subtype.
+                */
+               if (tp->mpc && !is_master_tp(tp))
+                       tcp_send_ack(sk);
                break;
 
        case TCP_FIN_WAIT1: {
@@ -5826,7 +5959,8 @@
                tmo = tcp_fin_time(sk);
                if (tmo > TCP_TIMEWAIT_LEN) {
                        inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN);
-               } else if (th->fin || sock_owned_by_user(sk)) {
+               } else if (th->fin || mptcp_is_data_fin(skb) ||
+                          sock_owned_by_user(sk)) {
                        /* Bad case. We could lose such FIN otherwise.
                         * It is not a big problem, but it looks confusing
                         * and not so rare event. We still can lose it now,
@@ -5855,6 +5989,9 @@
                        goto discard;
                }
                break;
+       case TCP_CLOSE:
+               if (tp->mp_killed)
+                       goto discard;
        }
 
        /* step 6: check the URG bit */
@@ -5875,7 +6012,11 @@
                 */
                if (sk->sk_shutdown & RCV_SHUTDOWN) {
                        if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq &&
-                           after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt)) {
+                           after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt) &&
+                           !tp->mpc) {
+                               /* In case of mptcp, the reset is handled by
+                                * mptcp_rcv_state_process
+                                */
                                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
                                tcp_reset(sk);
                                return 1;
diff -Nur linux-3.14.45.orig/net/ipv4/tcp_ipv4.c linux-3.14.45/net/ipv4/tcp_ipv4.c
--- linux-3.14.45.orig/net/ipv4/tcp_ipv4.c      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/tcp_ipv4.c   2015-06-24 14:15:48.883862476 +0200
@@ -67,6 +67,8 @@
 #include <net/icmp.h>
 #include <net/inet_hashtables.h>
 #include <net/tcp.h>
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
 #include <net/transp_v6.h>
 #include <net/ipv6.h>
 #include <net/inet_common.h>
@@ -99,7 +101,7 @@
 struct inet_hashinfo tcp_hashinfo;
 EXPORT_SYMBOL(tcp_hashinfo);
 
-static inline __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
+__u32 tcp_v4_init_sequence(const struct sk_buff *skb)
 {
        return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
                                          ip_hdr(skb)->saddr,
@@ -335,7 +337,7 @@
        struct inet_sock *inet;
        const int type = icmp_hdr(icmp_skb)->type;
        const int code = icmp_hdr(icmp_skb)->code;
-       struct sock *sk;
+       struct sock *sk, *meta_sk;
        struct sk_buff *skb;
        struct request_sock *req;
        __u32 seq;
@@ -359,13 +361,19 @@
                return;
        }
 
-       bh_lock_sock(sk);
+       tp = tcp_sk(sk);
+       if (tp->mpc)
+               meta_sk = mptcp_meta_sk(sk);
+       else
+               meta_sk = sk;
+
+       bh_lock_sock(meta_sk);
        /* If too many ICMPs get dropped on busy
         * servers this needs to be solved differently.
         * We do take care of PMTU discovery (RFC1191) special case :
         * we can receive locally generated ICMP messages while socket is held.
         */
-       if (sock_owned_by_user(sk)) {
+       if (sock_owned_by_user(meta_sk)) {
                if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
                        NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
        }
@@ -378,7 +386,6 @@
        }
 
        icsk = inet_csk(sk);
-       tp = tcp_sk(sk);
        req = tp->fastopen_rsk;
        seq = ntohl(th->seq);
        if (sk->sk_state != TCP_LISTEN &&
@@ -412,11 +419,13 @@
                                goto out;
 
                        tp->mtu_info = info;
-                       if (!sock_owned_by_user(sk)) {
+                       if (!sock_owned_by_user(meta_sk)) {
                                tcp_v4_mtu_reduced(sk);
                        } else {
                                if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
                                        sock_hold(sk);
+                               if (tp->mpc)
+                                       mptcp_tsq_flags(sk);
                        }
                        goto out;
                }
@@ -432,7 +441,7 @@
 
                /* XXX (TFO) - revisit the following logic for TFO */
 
-               if (sock_owned_by_user(sk))
+               if (sock_owned_by_user(meta_sk))
                        break;
 
                icsk->icsk_backoff--;
@@ -474,7 +483,7 @@
        switch (sk->sk_state) {
                struct request_sock *req, **prev;
        case TCP_LISTEN:
-               if (sock_owned_by_user(sk))
+               if (sock_owned_by_user(meta_sk))
                        goto out;
 
                req = inet_csk_search_req(sk, &prev, th->dest,
@@ -507,7 +516,7 @@
                               It can f.e. if SYNs crossed,
                               or Fast Open.
                             */
-               if (!sock_owned_by_user(sk)) {
+               if (!sock_owned_by_user(meta_sk)) {
                        sk->sk_err = err;
 
                        sk->sk_error_report(sk);
@@ -536,7 +545,7 @@
         */
 
        inet = inet_sk(sk);
-       if (!sock_owned_by_user(sk) && inet->recverr) {
+       if (!sock_owned_by_user(meta_sk) && inet->recverr) {
                sk->sk_err = err;
                sk->sk_error_report(sk);
        } else  { /* Only an error on timeout */
@@ -544,7 +553,7 @@
        }
 
 out:
-       bh_unlock_sock(sk);
+       bh_unlock_sock(meta_sk);
        sock_put(sk);
 }
 
@@ -586,7 +595,7 @@
  *     Exception: precedence violation. We do not implement it in any case.
  */
 
-static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
+void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
 {
        const struct tcphdr *th = tcp_hdr(skb);
        struct {
@@ -711,10 +720,10 @@
    outside socket context is ugly, certainly. What can I do?
  */
 
-static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
+static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 data_ack,
                            u32 win, u32 tsval, u32 tsecr, int oif,
                            struct tcp_md5sig_key *key,
-                           int reply_flags, u8 tos)
+                           int reply_flags, u8 tos, int mptcp)
 {
        const struct tcphdr *th = tcp_hdr(skb);
        struct {
@@ -723,6 +732,10 @@
 #ifdef CONFIG_TCP_MD5SIG
                           + (TCPOLEN_MD5SIG_ALIGNED >> 2)
 #endif
+#ifdef CONFIG_MPTCP
+                          + ((MPTCP_SUB_LEN_DSS >> 2) +
+                             (MPTCP_SUB_LEN_ACK >> 2))
+#endif
                        ];
        } rep;
        struct ip_reply_arg arg;
@@ -767,6 +780,21 @@
                                    ip_hdr(skb)->daddr, &rep.th);
        }
 #endif
+#ifdef CONFIG_MPTCP
+       if (mptcp) {
+               int offset = (tsecr) ? 3 : 0;
+               /* Construction of 32-bit data_ack */
+               rep.opt[offset++] = htonl((TCPOPT_MPTCP << 24) |
+                                         ((MPTCP_SUB_LEN_DSS + MPTCP_SUB_LEN_ACK) << 16) |
+                                         (0x20 << 8) |
+                                         (0x01));
+               rep.opt[offset] = htonl(data_ack);
+
+               arg.iov[0].iov_len += MPTCP_SUB_LEN_DSS + MPTCP_SUB_LEN_ACK;
+               rep.th.doff = arg.iov[0].iov_len / 4;
+       }
+#endif /* CONFIG_MPTCP */
+
        arg.flags = reply_flags;
        arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
                                      ip_hdr(skb)->saddr, /* XXX */
@@ -786,36 +814,44 @@
 {
        struct inet_timewait_sock *tw = inet_twsk(sk);
        struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
+       u32 data_ack = 0;
+       int mptcp = 0;
+
+       if (tcptw->mptcp_tw && tcptw->mptcp_tw->meta_tw) {
+               data_ack = (u32)tcptw->mptcp_tw->rcv_nxt;
+               mptcp = 1;
+       }
 
        tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
+                       data_ack,
                        tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
                        tcp_time_stamp + tcptw->tw_ts_offset,
                        tcptw->tw_ts_recent,
                        tw->tw_bound_dev_if,
                        tcp_twsk_md5_key(tcptw),
                        tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
-                       tw->tw_tos
+                       tw->tw_tos, mptcp
                        );
 
        inet_twsk_put(tw);
 }
 
-static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
-                                 struct request_sock *req)
+void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+                          struct request_sock *req)
 {
        /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
         * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
         */
        tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
                        tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
-                       tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
+                       tcp_rsk(req)->rcv_nxt, 0, req->rcv_wnd,
                        tcp_time_stamp,
                        req->ts_recent,
                        0,
                        tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
                                          AF_INET),
                        inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
-                       ip_hdr(skb)->tos);
+                       ip_hdr(skb)->tos, 0);
 }
 
 /*
@@ -823,9 +859,9 @@
  *     This still operates on a request_sock only, not on a big
  *     socket.
  */
-static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
-                             struct request_sock *req,
-                             u16 queue_mapping)
+int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
+                      struct request_sock *req,
+                      u16 queue_mapping)
 {
        const struct inet_request_sock *ireq = inet_rsk(req);
        struct flowi4 fl4;
@@ -853,7 +889,7 @@
        return err;
 }
 
-static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req)
+int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req)
 {
        int res = tcp_v4_send_synack(sk, NULL, req, 0);
 
@@ -865,7 +901,7 @@
 /*
  *     IPv4 request_sock destructor.
  */
-static void tcp_v4_reqsk_destructor(struct request_sock *req)
+void tcp_v4_reqsk_destructor(struct request_sock *req)
 {
        kfree(inet_rsk(req)->opt);
 }
@@ -905,7 +941,7 @@
 /*
  * Save and compile IPv4 options into the request_sock if needed.
  */
-static struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb)
+struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb)
 {
        const struct ip_options *opt = &(IPCB(skb)->opt);
        struct ip_options_rcu *dopt = NULL;
@@ -1257,7 +1293,7 @@
 };
 
 #ifdef CONFIG_TCP_MD5SIG
-static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
+const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
        .md5_lookup     =       tcp_v4_reqsk_md5_lookup,
        .calc_md5_hash  =       tcp_v4_md5_hash_skb,
 };
@@ -1415,7 +1451,7 @@
        tcp_init_congestion_control(child);
        tcp_mtup_init(child);
        tcp_init_metrics(child);
-       tcp_init_buffer_space(child);
+       tp->init_buffer_space(child);
 
        /* Queue the data carried in the SYN packet. We need to first
         * bump skb's refcnt because the caller will attempt to free it.
@@ -1447,6 +1483,7 @@
 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_options_received tmp_opt;
+       struct mptcp_options_received mopt;
        struct request_sock *req;
        struct inet_request_sock *ireq;
        struct tcp_sock *tp = tcp_sk(sk);
@@ -1461,6 +1498,22 @@
        struct sk_buff *skb_synack;
        int do_fastopen;
 
+       tcp_clear_options(&tmp_opt);
+       tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
+       tmp_opt.user_mss  = tp->rx_opt.user_mss;
+       mptcp_init_mp_opt(&mopt);
+       tcp_parse_options(skb, &tmp_opt, &mopt, 0, want_cookie ? NULL : &foc);
+
+#ifdef CONFIG_MPTCP
+       /* MPTCP structures not initialized, so clear MPTCP fields */
+       if  (mptcp_init_failed)
+               mptcp_init_mp_opt(&mopt);
+
+       if (mopt.is_mp_join)
+               return mptcp_do_join_short(skb, &mopt, &tmp_opt, sock_net(sk));
+       if (mopt.drop_me)
+               goto drop;
+#endif
        /* Never answer to SYNs send to broadcast or multicast */
        if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
                goto drop;
@@ -1486,7 +1539,22 @@
                goto drop;
        }
 
-       req = inet_reqsk_alloc(&tcp_request_sock_ops);
+#ifdef CONFIG_MPTCP
+       if (sysctl_mptcp_enabled == MPTCP_APP && !tp->mptcp_enabled)
+               mopt.saw_mpc = 0;
+       if (mopt.saw_mpc && !want_cookie) {
+               req = inet_reqsk_alloc(&mptcp_request_sock_ops);
+
+               if (!req)
+                       goto drop;
+
+               mptcp_rsk(req)->mpcb = NULL;
+               mptcp_rsk(req)->dss_csum = mopt.dss_csum;
+               mptcp_rsk(req)->collide_tk.pprev = NULL;
+       } else
+#endif
+               req = inet_reqsk_alloc(&tcp_request_sock_ops);
+
        if (!req)
                goto drop;
 
@@ -1494,17 +1562,15 @@
        tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
 #endif
 
-       tcp_clear_options(&tmp_opt);
-       tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
-       tmp_opt.user_mss  = tp->rx_opt.user_mss;
-       tcp_parse_options(skb, &tmp_opt, 0, want_cookie ? NULL : &foc);
-
        if (want_cookie && !tmp_opt.saw_tstamp)
                tcp_clear_options(&tmp_opt);
 
        tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
        tcp_openreq_init(req, &tmp_opt, skb);
 
+       if (mopt.saw_mpc && !want_cookie)
+               mptcp_reqsk_new_mptcp(req, &tmp_opt, &mopt, skb);
+
        ireq = inet_rsk(req);
        ireq->ir_loc_addr = daddr;
        ireq->ir_rmt_addr = saddr;
@@ -1716,7 +1782,7 @@
 }
 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
 
-static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
+struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
 {
        struct tcphdr *th = tcp_hdr(skb);
        const struct iphdr *iph = ip_hdr(skb);
@@ -1733,8 +1799,15 @@
 
        if (nsk) {
                if (nsk->sk_state != TCP_TIME_WAIT) {
+                       /* Don't lock again the meta-sk. It has been locked
+                        * before mptcp_v4_do_rcv.
+                        */
+                       if (tcp_sk(nsk)->mpc && !is_meta_sk(sk))
+                               bh_lock_sock(mptcp_meta_sk(nsk));
                        bh_lock_sock(nsk);
+
                        return nsk;
+
                }
                inet_twsk_put(inet_twsk(nsk));
                return NULL;
@@ -1791,6 +1864,9 @@
                goto discard;
 #endif
 
+       if (is_meta_sk(sk))
+               return mptcp_v4_do_rcv(sk, skb);
+
        if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
                struct dst_entry *dst = sk->sk_rx_dst;
 
@@ -1922,7 +1998,7 @@
        } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
                wake_up_interruptible_sync_poll(sk_sleep(sk),
                                           POLLIN | POLLRDNORM | POLLRDBAND);
-               if (!inet_csk_ack_scheduled(sk))
+               if (!inet_csk_ack_scheduled(sk) && !tp->mpc)
                        inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
                                                  (3 * tcp_rto_min(sk)) / 4,
                                                  TCP_RTO_MAX);
@@ -1939,7 +2015,7 @@
 {
        const struct iphdr *iph;
        const struct tcphdr *th;
-       struct sock *sk;
+       struct sock *sk, *meta_sk = NULL;
        int ret;
        struct net *net = dev_net(skb->dev);
 
@@ -1972,18 +2048,42 @@
        TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
                                    skb->len - th->doff * 4);
        TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
+#ifdef CONFIG_MPTCP
+       TCP_SKB_CB(skb)->mptcp_flags = 0;
+       TCP_SKB_CB(skb)->dss_off = 0;
+#endif
        TCP_SKB_CB(skb)->when    = 0;
        TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
        TCP_SKB_CB(skb)->sacked  = 0;
 
        sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
-       if (!sk)
-               goto no_tcp_socket;
 
 process:
-       if (sk->sk_state == TCP_TIME_WAIT)
+       if (sk && sk->sk_state == TCP_TIME_WAIT)
                goto do_time_wait;
 
+#ifdef CONFIG_MPTCP
+       if (!sk && th->syn && !th->ack) {
+               int ret = mptcp_lookup_join(skb, NULL);
+
+               if (ret < 0) {
+                       tcp_v4_send_reset(NULL, skb);
+                       goto discard_it;
+               } else if (ret > 0) {
+                       return 0;
+               }
+       }
+
+       /* Is there a pending request sock for this segment ? */
+       if ((!sk || sk->sk_state == TCP_LISTEN) && mptcp_check_req(skb, net)) {
+               if (sk)
+                       sock_put(sk);
+               return 0;
+       }
+#endif
+       if (!sk)
+               goto no_tcp_socket;
+
        if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
                NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
                goto discard_and_relse;
@@ -1999,11 +2099,21 @@
        sk_mark_napi_id(sk, skb);
        skb->dev = NULL;
 
-       bh_lock_sock_nested(sk);
+       if (tcp_sk(sk)->mpc) {
+               meta_sk = mptcp_meta_sk(sk);
+
+               bh_lock_sock_nested(meta_sk);
+               if (sock_owned_by_user(meta_sk))
+                       skb->sk = sk;
+       } else {
+               meta_sk = sk;
+               bh_lock_sock_nested(sk);
+       }
+
        ret = 0;
-       if (!sock_owned_by_user(sk)) {
+       if (!sock_owned_by_user(meta_sk)) {
 #ifdef CONFIG_NET_DMA
-               struct tcp_sock *tp = tcp_sk(sk);
+               struct tcp_sock *tp = tcp_sk(meta_sk);
                if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
                        tp->ucopy.dma_chan = net_dma_find_channel();
                if (tp->ucopy.dma_chan)
@@ -2011,16 +2121,16 @@
                else
 #endif
                {
-                       if (!tcp_prequeue(sk, skb))
+                       if (!tcp_prequeue(meta_sk, skb))
                                ret = tcp_v4_do_rcv(sk, skb);
                }
-       } else if (unlikely(sk_add_backlog(sk, skb,
-                                          sk->sk_rcvbuf + sk->sk_sndbuf))) {
-               bh_unlock_sock(sk);
+       } else if (unlikely(sk_add_backlog(meta_sk, skb,
+                                          meta_sk->sk_rcvbuf + meta_sk->sk_sndbuf))) {
+               bh_unlock_sock(meta_sk);
                NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
                goto discard_and_relse;
        }
-       bh_unlock_sock(sk);
+       bh_unlock_sock(meta_sk);
 
        sock_put(sk);
 
@@ -2075,6 +2185,18 @@
                        sk = sk2;
                        goto process;
                }
+#ifdef CONFIG_MPTCP
+               if (th->syn && !th->ack) {
+                       int ret = mptcp_lookup_join(skb, inet_twsk(sk));
+
+                       if (ret < 0) {
+                               tcp_v4_send_reset(NULL, skb);
+                               goto discard_it;
+                       } else if (ret > 0) {
+                               return 0;
+                       }
+               }
+#endif
                /* Fall through to ACK */
        }
        case TCP_TW_ACK:
@@ -2158,6 +2280,11 @@
 
        tcp_cleanup_congestion_control(sk);
 
+       if (tp->mpc)
+               mptcp_destroy_sock(sk);
+       if (tp->inside_tk_table)
+               mptcp_hash_remove(tp);
+
        /* Cleanup up the write buffer. */
        tcp_write_queue_purge(sk);
 
diff -Nur linux-3.14.45.orig/net/ipv4/tcp_minisocks.c linux-3.14.45/net/ipv4/tcp_minisocks.c
--- linux-3.14.45.orig/net/ipv4/tcp_minisocks.c 2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/tcp_minisocks.c      2015-06-24 14:15:48.887862480 +0200
@@ -18,11 +18,13 @@
  *             Jorge Cwik, <jorge@laser.satlink.net>
  */
 
+#include <linux/kconfig.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/sysctl.h>
 #include <linux/workqueue.h>
+#include <net/mptcp.h>
 #include <net/tcp.h>
 #include <net/inet_common.h>
 #include <net/xfrm.h>
@@ -95,10 +97,13 @@
        struct tcp_options_received tmp_opt;
        struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
        bool paws_reject = false;
+       struct mptcp_options_received mopt;
 
        tmp_opt.saw_tstamp = 0;
        if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {
-               tcp_parse_options(skb, &tmp_opt, 0, NULL);
+               mptcp_init_mp_opt(&mopt);
+
+               tcp_parse_options(skb, &tmp_opt, &mopt, 0, NULL);
 
                if (tmp_opt.saw_tstamp) {
                        tmp_opt.rcv_tsecr       -= tcptw->tw_ts_offset;
@@ -106,6 +111,11 @@
                        tmp_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
                        paws_reject = tcp_paws_reject(&tmp_opt, th->rst);
                }
+
+               if (unlikely(mopt.mp_fclose) && tcptw->mptcp_tw) {
+                       if (mopt.mptcp_key == tcptw->mptcp_tw->loc_key)
+                               goto kill_with_rst;
+               }
        }
 
        if (tw->tw_substate == TCP_FIN_WAIT2) {
@@ -128,6 +138,16 @@
                if (!th->ack ||
                    !after(TCP_SKB_CB(skb)->end_seq, tcptw->tw_rcv_nxt) ||
                    TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq) {
+                       /* If mptcp_is_data_fin() returns true, we are sure that
+                        * mopt has been initialized - otherwise it would not
+                        * be a DATA_FIN.
+                        */
+                       if (tcptw->mptcp_tw && tcptw->mptcp_tw->meta_tw &&
+                           mptcp_is_data_fin(skb) &&
+                           TCP_SKB_CB(skb)->seq == tcptw->tw_rcv_nxt &&
+                           mopt.data_seq + 1 == (u32)tcptw->mptcp_tw->rcv_nxt)
+                               return TCP_TW_ACK;
+
                        inet_twsk_put(tw);
                        return TCP_TW_SUCCESS;
                }
@@ -270,6 +290,11 @@
        const struct tcp_sock *tp = tcp_sk(sk);
        bool recycle_ok = false;
 
+       if (is_meta_sk(sk)) {
+               mptcp_update_tw_socks(tp, state);
+               goto tcp_done;
+       }
+
        if (tcp_death_row.sysctl_tw_recycle && tp->rx_opt.ts_recent_stamp)
                recycle_ok = tcp_remember_stamp(sk);
 
@@ -290,6 +315,15 @@
                tcptw->tw_ts_recent_stamp = tp->rx_opt.ts_recent_stamp;
                tcptw->tw_ts_offset     = tp->tsoffset;
 
+               if (tp->mpc) {
+                       if (mptcp_time_wait(sk, tcptw)) {
+                               inet_twsk_free(tw);
+                               goto exit;
+                       }
+               } else {
+                       tcptw->mptcp_tw = NULL;
+               }
+
 #if IS_ENABLED(CONFIG_IPV6)
                if (tw->tw_family == PF_INET6) {
                        struct ipv6_pinfo *np = inet6_sk(sk);
@@ -347,15 +381,19 @@
                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPTIMEWAITOVERFLOW);
        }
 
+exit:
        tcp_update_metrics(sk);
+tcp_done:
        tcp_done(sk);
 }
 
 void tcp_twsk_destructor(struct sock *sk)
 {
-#ifdef CONFIG_TCP_MD5SIG
        struct tcp_timewait_sock *twsk = tcp_twsk(sk);
 
+       if (twsk->mptcp_tw)
+               mptcp_twsk_destructor(twsk);
+#ifdef CONFIG_TCP_MD5SIG
        if (twsk->tw_md5_key)
                kfree_rcu(twsk->tw_md5_key, rcu);
 #endif
@@ -392,6 +430,9 @@
 
                newtp->snd_sml = newtp->snd_una =
                newtp->snd_nxt = newtp->snd_up = treq->snt_isn + 1;
+#ifdef CONFIG_MPTCP
+               memset(&newtp->rcvq_space, 0, sizeof(newtp->rcvq_space));
+#endif
 
                tcp_prequeue_init(newtp);
                INIT_LIST_HEAD(&newtp->tsq_node);
@@ -436,7 +477,11 @@
 
                newtp->urg_data = 0;
 
-               if (sock_flag(newsk, SOCK_KEEPOPEN))
+               /* MPTCP: If we are creating a subflow, KEEPOPEN might have been
+                * set on the meta. But, keepalive is entirely handled at the
+                * meta-socket, so let's keep it there.
+                */
+               if (sock_flag(newsk, SOCK_KEEPOPEN) && is_meta_sk(sk))
                        inet_csk_reset_keepalive_timer(newsk,
                                                       keepalive_time_when(newtp));
 
@@ -468,6 +513,8 @@
                        newtp->rx_opt.ts_recent_stamp = 0;
                        newtp->tcp_header_len = sizeof(struct tcphdr);
                }
+               if (treq->saw_mpc)
+                       newtp->tcp_header_len += MPTCP_SUB_LEN_DSM_ALIGN;
                newtp->tsoffset = 0;
 #ifdef CONFIG_TCP_MD5SIG
                newtp->md5sig_info = NULL;      /*XXX*/
@@ -504,16 +551,20 @@
                           bool fastopen)
 {
        struct tcp_options_received tmp_opt;
+       struct mptcp_options_received mopt;
        struct sock *child;
        const struct tcphdr *th = tcp_hdr(skb);
        __be32 flg = tcp_flag_word(th) & (TCP_FLAG_RST|TCP_FLAG_SYN|TCP_FLAG_ACK);
        bool paws_reject = false;
 
-       BUG_ON(fastopen == (sk->sk_state == TCP_LISTEN));
+       BUG_ON(!tcp_sk(sk)->mpc && fastopen == (sk->sk_state == TCP_LISTEN));
 
        tmp_opt.saw_tstamp = 0;
+
+       mptcp_init_mp_opt(&mopt);
+
        if (th->doff > (sizeof(struct tcphdr)>>2)) {
-               tcp_parse_options(skb, &tmp_opt, 0, NULL);
+               tcp_parse_options(skb, &tmp_opt, &mopt, 0, NULL);
 
                if (tmp_opt.saw_tstamp) {
                        tmp_opt.ts_recent = req->ts_recent;
@@ -552,7 +603,14 @@
                 *
                 * Reset timer after retransmitting SYNACK, similar to
                 * the idea of fast retransmit in recovery.
+                *
+                * Fall back to TCP if MP_CAPABLE is not set.
                 */
+
+               if (tcp_rsk(req)->saw_mpc && !mopt.saw_mpc)
+                       tcp_rsk(req)->saw_mpc = false;
+
+
                if (!inet_rtx_syn_ack(sk, req))
                        req->expires = min(TCP_TIMEOUT_INIT << req->num_timeout,
                                           TCP_RTO_MAX) + jiffies;
@@ -674,7 +732,20 @@
 
        /* While TCP_DEFER_ACCEPT is active, drop bare ACK. */
        if (req->num_timeout < inet_csk(sk)->icsk_accept_queue.rskq_defer_accept &&
-           TCP_SKB_CB(skb)->end_seq == tcp_rsk(req)->rcv_isn + 1) {
+           TCP_SKB_CB(skb)->end_seq == tcp_rsk(req)->rcv_isn + 1 &&
+           /* TODO MPTCP:
+            * We do this here, because otherwise options sent in the third ack,
+            * or duplicate fourth ack will get lost. Options like MP_PRIO, ADD_ADDR,...
+            *
+            * We could store them in request_sock, but this would mean that we
+            * have to put tcp_options_received and mptcp_options_received in there,
+            * increasing considerably the size of the request-sock.
+            *
+            * As soon as we have reworked the request-sock MPTCP-fields and
+            * created a mptcp_request_sock structure, we can handle options
+            * correclty there without increasing request_sock.
+            */
+           !tcp_rsk(req)->saw_mpc) {
                inet_rsk(req)->acked = 1;
                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDEFERACCEPTDROP);
                return NULL;
@@ -686,10 +757,29 @@
         * ESTABLISHED STATE. If it will be dropped after
         * socket is created, wait for troubles.
         */
-       child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
+#ifdef CONFIG_MPTCP
+       if (tcp_sk(sk)->mpc)
+               /* MPTCP: We call the mptcp-specific syn_recv_sock */
+               child = tcp_sk(sk)->mpcb->syn_recv_sock(sk, skb, req, NULL);
+       else
+#endif
+               child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb,
+                               req, NULL);
+
        if (child == NULL)
                goto listen_overflow;
 
+       if (!is_meta_sk(sk)) {
+               int ret = mptcp_check_req_master(sk, child, req, prev, &mopt);
+               if (ret < 0)
+                       goto listen_overflow;
+
+               /* MPTCP-supported */
+               if (!ret)
+                       return tcp_sk(child)->mpcb->master_sk;
+       } else {
+               return mptcp_check_req_child(sk, child, req, prev, &mopt);
+       }
        inet_csk_reqsk_queue_unlink(sk, req, prev);
        inet_csk_reqsk_queue_removed(sk, req);
 
@@ -739,8 +829,9 @@
 {
        int ret = 0;
        int state = child->sk_state;
+       struct sock *meta_sk = tcp_sk(child)->mpc ? mptcp_meta_sk(child) : child;
 
-       if (!sock_owned_by_user(child)) {
+       if (!sock_owned_by_user(meta_sk)) {
                ret = tcp_rcv_state_process(child, skb, tcp_hdr(skb),
                                            skb->len);
                /* Wakeup parent, send SIGIO */
@@ -751,10 +842,14 @@
                 * in main socket hash table and lock on listening
                 * socket does not protect us more.
                 */
-               __sk_add_backlog(child, skb);
+               if (tcp_sk(child)->mpc)
+                       skb->sk = child;
+               __sk_add_backlog(meta_sk, skb);
        }
 
-       bh_unlock_sock(child);
+       if (tcp_sk(child)->mpc)
+               bh_unlock_sock(child);
+       bh_unlock_sock(meta_sk);
        sock_put(child);
        return ret;
 }
diff -Nur linux-3.14.45.orig/net/ipv4/tcp_output.c linux-3.14.45/net/ipv4/tcp_output.c
--- linux-3.14.45.orig/net/ipv4/tcp_output.c    2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/tcp_output.c 2015-06-24 14:15:48.887862480 +0200
@@ -36,6 +36,12 @@
 
 #define pr_fmt(fmt) "TCP: " fmt
 
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/mptcp_v6.h>
+#endif
+#include <net/ipv6.h>
 #include <net/tcp.h>
 
 #include <linux/compiler.h>
@@ -72,7 +78,7 @@
                           int push_one, gfp_t gfp);
 
 /* Account for new data that has been sent to the network. */
-static void tcp_event_new_data_sent(struct sock *sk, const struct sk_buff *skb)
+void tcp_event_new_data_sent(struct sock *sk, const struct sk_buff *skb)
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
@@ -211,7 +217,7 @@
 void tcp_select_initial_window(int __space, __u32 mss,
                               __u32 *rcv_wnd, __u32 *window_clamp,
                               int wscale_ok, __u8 *rcv_wscale,
-                              __u32 init_rcv_wnd)
+                              __u32 init_rcv_wnd, const struct sock *sk)
 {
        unsigned int space = (__space < 0 ? 0 : __space);
 
@@ -266,11 +272,15 @@
  * value can be stuffed directly into th->window for an outgoing
  * frame.
  */
-static u16 tcp_select_window(struct sock *sk)
+u16 tcp_select_window(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
-       u32 cur_win = tcp_receive_window(tp);
-       u32 new_win = __tcp_select_window(sk);
+       /* The window must never shrink at the meta-level. At the subflow we
+        * have to allow this. Otherwise we may announce a window too large
+        * for the current meta-level sk_rcvbuf.
+        */
+       u32 cur_win = tcp_receive_window(tp->mpc ? tcp_sk(mptcp_meta_sk(sk)) : tp);
+       u32 new_win = tp->__select_window(sk);
 
        /* Never shrink the offered window */
        if (new_win < cur_win) {
@@ -283,6 +293,7 @@
                 */
                new_win = ALIGN(cur_win, 1 << tp->rx_opt.rcv_wscale);
        }
+
        tp->rcv_wnd = new_win;
        tp->rcv_wup = tp->rcv_nxt;
 
@@ -361,7 +372,7 @@
 /* Constructs common control bits of non-data skb. If SYN/FIN is present,
  * auto increment end seqno.
  */
-static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags)
+void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags)
 {
        struct skb_shared_info *shinfo = skb_shinfo(skb);
 
@@ -381,7 +392,7 @@
        TCP_SKB_CB(skb)->end_seq = seq;
 }
 
-static inline bool tcp_urg_mode(const struct tcp_sock *tp)
+bool tcp_urg_mode(const struct tcp_sock *tp)
 {
        return tp->snd_una != tp->snd_up;
 }
@@ -391,17 +402,7 @@
 #define OPTION_MD5             (1 << 2)
 #define OPTION_WSCALE          (1 << 3)
 #define OPTION_FAST_OPEN_COOKIE        (1 << 8)
-
-struct tcp_out_options {
-       u16 options;            /* bit field of OPTION_* */
-       u16 mss;                /* 0 to disable */
-       u8 ws;                  /* window scale, 0 to disable */
-       u8 num_sack_blocks;     /* number of SACK blocks to include */
-       u8 hash_size;           /* bytes in hash_location */
-       __u8 *hash_location;    /* temporary pointer, overloaded */
-       __u32 tsval, tsecr;     /* need to include OPTION_TS */
-       struct tcp_fastopen_cookie *fastopen_cookie;    /* Fast open cookie */
-};
+/* Before adding here - take a look at OPTION_MPTCP in include/net/mptcp.h */
 
 /* Write previously computed TCP options to the packet.
  *
@@ -417,7 +418,7 @@
  * (but it may well be that other scenarios fail similarly).
  */
 static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
-                             struct tcp_out_options *opts)
+                             struct tcp_out_options *opts, struct sk_buff *skb)
 {
        u16 options = opts->options;    /* mungable copy */
 
@@ -500,6 +501,9 @@
                }
                ptr += (foc->len + 3) >> 2;
        }
+
+       if (unlikely(OPTION_MPTCP & opts->options))
+               mptcp_options_write(ptr, tp, opts, skb);
 }
 
 /* Compute TCP options for SYN packets. This is not the final
@@ -551,6 +555,8 @@
                if (unlikely(!(OPTION_TS & opts->options)))
                        remaining -= TCPOLEN_SACKPERM_ALIGNED;
        }
+       if (tp->request_mptcp || tp->mpc)
+               mptcp_syn_options(sk, opts, &remaining);
 
        if (fastopen && fastopen->cookie.len >= 0) {
                u32 need = TCPOLEN_EXP_FASTOPEN_BASE + fastopen->cookie.len;
@@ -624,6 +630,9 @@
                }
        }
 
+       if (tcp_rsk(req)->saw_mpc)
+               mptcp_synack_options(req, opts, &remaining);
+
        return MAX_TCP_OPTION_SPACE - remaining;
 }
 
@@ -657,16 +666,22 @@
                opts->tsecr = tp->rx_opt.ts_recent;
                size += TCPOLEN_TSTAMP_ALIGNED;
        }
+       if (tp->mpc)
+               mptcp_established_options(sk, skb, opts, &size);
 
        eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
        if (unlikely(eff_sacks)) {
-               const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
-               opts->num_sack_blocks =
-                       min_t(unsigned int, eff_sacks,
-                             (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
-                             TCPOLEN_SACK_PERBLOCK);
-               size += TCPOLEN_SACK_BASE_ALIGNED +
-                       opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
+               const unsigned remaining = MAX_TCP_OPTION_SPACE - size;
+               if (remaining < TCPOLEN_SACK_BASE_ALIGNED)
+                       opts->num_sack_blocks = 0;
+               else
+                       opts->num_sack_blocks =
+                           min_t(unsigned int, eff_sacks,
+                                 (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
+                                 TCPOLEN_SACK_PERBLOCK);
+               if (opts->num_sack_blocks)
+                       size += TCPOLEN_SACK_BASE_ALIGNED +
+                           opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
        }
 
        return size;
@@ -714,7 +729,7 @@
        unsigned long flags;
        struct list_head *q, *n;
        struct tcp_sock *tp;
-       struct sock *sk;
+       struct sock *sk, *meta_sk;
 
        local_irq_save(flags);
        list_splice_init(&tsq->head, &list);
@@ -725,15 +740,27 @@
                list_del(&tp->tsq_node);
 
                sk = (struct sock *)tp;
-               bh_lock_sock(sk);
+               meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
+               bh_lock_sock(meta_sk);
 
-               if (!sock_owned_by_user(sk)) {
+               if (!sock_owned_by_user(meta_sk)) {
                        tcp_tsq_handler(sk);
+                       if (tp->mpc)
+                               tcp_tsq_handler(meta_sk);
                } else {
                        /* defer the work to tcp_release_cb() */
                        set_bit(TCP_TSQ_DEFERRED, &tp->tsq_flags);
+
+                       /* For MPTCP, we set the tsq-bit on the meta, and the
+                        * subflow as we don't know if the limitation happened
+                        * while inside mptcp_write_xmit or during tcp_write_xmit.
+                        */
+                       if (tp->mpc) {
+                               set_bit(TCP_TSQ_DEFERRED, &tcp_sk(meta_sk)->tsq_flags);
+                               mptcp_tsq_flags(sk);
+                       }
                }
-               bh_unlock_sock(sk);
+               bh_unlock_sock(meta_sk);
 
                clear_bit(TSQ_QUEUED, &tp->tsq_flags);
                sk_free(sk);
@@ -743,7 +770,10 @@
 #define TCP_DEFERRED_ALL ((1UL << TCP_TSQ_DEFERRED) |          \
                          (1UL << TCP_WRITE_TIMER_DEFERRED) |   \
                          (1UL << TCP_DELACK_TIMER_DEFERRED) |  \
-                         (1UL << TCP_MTU_REDUCED_DEFERRED))
+                         (1UL << TCP_MTU_REDUCED_DEFERRED) |   \
+                         (1UL << MPTCP_PATH_MANAGER) |         \
+                         (1UL << MPTCP_SUB_DEFERRED))
+
 /**
  * tcp_release_cb - tcp release_sock() callback
  * @sk: socket
@@ -790,6 +820,13 @@
                inet_csk(sk)->icsk_af_ops->mtu_reduced(sk);
                __sock_put(sk);
        }
+       if (flags & (1UL << MPTCP_PATH_MANAGER)) {
+               if (tcp_sk(sk)->mpcb->pm_ops->release_sock)
+                       tcp_sk(sk)->mpcb->pm_ops->release_sock(sk);
+               __sock_put(sk);
+       }
+       if (flags & (1UL << MPTCP_SUB_DEFERRED))
+               mptcp_tsq_sub_deferred(sk);
 }
 EXPORT_SYMBOL(tcp_release_cb);
 
@@ -849,8 +886,8 @@
  * We are working here with either a clone of the original
  * SKB, or a fresh unique copy made by the retransmit engine.
  */
-static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
-                           gfp_t gfp_mask)
+int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
+                       gfp_t gfp_mask)
 {
        const struct inet_connection_sock *icsk = inet_csk(sk);
        struct inet_sock *inet;
@@ -878,10 +915,28 @@
                        NET_INC_STATS(sock_net(sk),
                                      LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES);
 
-               if (unlikely(skb_cloned(skb)))
-                       skb = pskb_copy(skb, gfp_mask);
-               else
+               if (unlikely(skb_cloned(skb))) {
+                       struct sk_buff *newskb;
+                       if (mptcp_is_data_seq(skb))
+                               skb_push(skb, MPTCP_SUB_LEN_DSS_ALIGN +
+                                             MPTCP_SUB_LEN_ACK_ALIGN +
+                                             MPTCP_SUB_LEN_SEQ_ALIGN);
+
+                       newskb = pskb_copy(skb, gfp_mask);
+
+                       if (mptcp_is_data_seq(skb)) {
+                               skb_pull(skb, MPTCP_SUB_LEN_DSS_ALIGN +
+                                             MPTCP_SUB_LEN_ACK_ALIGN +
+                                             MPTCP_SUB_LEN_SEQ_ALIGN);
+                               if (newskb)
+                                       skb_pull(newskb, MPTCP_SUB_LEN_DSS_ALIGN +
+                                                        MPTCP_SUB_LEN_ACK_ALIGN +
+                                                        MPTCP_SUB_LEN_SEQ_ALIGN);
+                       }
+                       skb = newskb;
+               } else {
                        skb = skb_clone(skb, gfp_mask);
+               }
                if (unlikely(!skb))
                        return -ENOBUFS;
        }
@@ -929,7 +984,7 @@
                 */
                th->window      = htons(min(tp->rcv_wnd, 65535U));
        } else {
-               th->window      = htons(tcp_select_window(sk));
+               th->window      = htons(tp->select_window(sk));
        }
        th->check               = 0;
        th->urg_ptr             = 0;
@@ -945,7 +1000,7 @@
                }
        }
 
-       tcp_options_write((__be32 *)(th + 1), tp, &opts);
+       tcp_options_write((__be32 *)(th + 1), tp, &opts, skb);
        if (likely((tcb->tcp_flags & TCPHDR_SYN) == 0))
                TCP_ECN_send(sk, skb, tcp_header_size);
 
@@ -984,7 +1039,7 @@
  * NOTE: probe0 timer is not checked, do not forget tcp_push_pending_frames,
  * otherwise socket can stall.
  */
-static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb)
+void tcp_queue_skb(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
@@ -997,15 +1052,16 @@
 }
 
 /* Initialize TSO segments for a packet. */
-static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
-                                unsigned int mss_now)
+void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
+                         unsigned int mss_now)
 {
        struct skb_shared_info *shinfo = skb_shinfo(skb);
 
        /* Make sure we own this skb before messing gso_size/gso_segs */
        WARN_ON_ONCE(skb_cloned(skb));
 
-       if (skb->len <= mss_now || skb->ip_summed == CHECKSUM_NONE) {
+       if (skb->len <= mss_now || (is_meta_sk(sk) && !mptcp_sk_can_gso(sk)) ||
+           (!is_meta_sk(sk) && !sk_can_gso(sk)) || skb->ip_summed == CHECKSUM_NONE) {
                /* Avoid the costly divide in the normal
                 * non-TSO case.
                 */
@@ -1037,7 +1093,7 @@
 /* Pcount in the middle of the write queue got changed, we need to do various
  * tweaks to fix counters
  */
-static void tcp_adjust_pcount(struct sock *sk, const struct sk_buff *skb, int decr)
+void tcp_adjust_pcount(struct sock *sk, const struct sk_buff *skb, int decr)
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
@@ -1078,6 +1134,9 @@
        int nlen;
        u8 flags;
 
+       if (tcp_sk(sk)->mpc && mptcp_is_data_seq(skb))
+               mptcp_fragment(sk, skb, len, mss_now, 0);
+
        if (WARN_ON(len > skb->len))
                return -EINVAL;
 
@@ -1160,7 +1219,7 @@
  * eventually). The difference is that pulled data not copied, but
  * immediately discarded.
  */
-static void __pskb_trim_head(struct sk_buff *skb, int len)
+void __pskb_trim_head(struct sk_buff *skb, int len)
 {
        struct skb_shared_info *shinfo;
        int i, k, eat;
@@ -1201,6 +1260,9 @@
 /* Remove acked data from a packet in the transmit queue. */
 int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
 {
+       if (tcp_sk(sk)->mpc && !is_meta_sk(sk) && mptcp_is_data_seq(skb))
+               return mptcp_trim_head(sk, skb, len);
+
        if (skb_unclone(skb, GFP_ATOMIC))
                return -ENOMEM;
 
@@ -1218,6 +1280,15 @@
        if (tcp_skb_pcount(skb) > 1)
                tcp_set_skb_tso_segs(sk, skb, tcp_skb_mss(skb));
 
+#ifdef CONFIG_MPTCP
+       /* Some data got acked - we assume that the seq-number reached the dest.
+        * Anyway, our MPTCP-option has been trimmed above - we lost it here.
+        * Only remove the SEQ if the call does not come from a meta retransmit.
+        */
+       if (tcp_sk(sk)->mpc && !is_meta_sk(sk))
+               TCP_SKB_CB(skb)->mptcp_flags &= ~MPTCPHDR_SEQ;
+#endif
+
        return 0;
 }
 
@@ -1377,7 +1448,7 @@
 }
 
 /* Congestion window validation. (RFC2861) */
-static void tcp_cwnd_validate(struct sock *sk)
+void tcp_cwnd_validate(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
 
@@ -1411,8 +1482,8 @@
  * But we can avoid doing the divide again given we already have
  *  skb_pcount = skb->len / mss_now
  */
-static void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss_now,
-                               const struct sk_buff *skb)
+void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss_now,
+                        const struct sk_buff *skb)
 {
        if (skb->len < tcp_skb_pcount(skb) * mss_now)
                tp->snd_sml = TCP_SKB_CB(skb)->end_seq;
@@ -1433,19 +1504,28 @@
                 (!nonagle && tp->packets_out && tcp_minshall_check(tp)));
 }
 /* Returns the portion of skb which can be sent right away */
-static unsigned int tcp_mss_split_point(const struct sock *sk,
-                                       const struct sk_buff *skb,
-                                       unsigned int mss_now,
-                                       unsigned int max_segs,
-                                       int nonagle)
+unsigned int tcp_mss_split_point(const struct sock *sk,
+                                const struct sk_buff *skb,
+                                unsigned int mss_now,
+                                unsigned int max_segs,
+                                int nonagle)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
+       const struct sock *meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
        u32 partial, needed, window, max_len;
 
-       window = tcp_wnd_end(tp) - TCP_SKB_CB(skb)->seq;
+       if (!tp->mpc)
+               window = tcp_wnd_end(tp) - TCP_SKB_CB(skb)->seq;
+       else
+               /* We need to evaluate the available space in the sending window
+                * at the subflow level. However, the subflow seq has not yet
+                * been set. Nevertheless we know that the caller will set it to
+                * write_seq.
+                */
+               window = tcp_wnd_end(tp) - tp->write_seq;
        max_len = mss_now * max_segs;
 
-       if (likely(max_len <= window && skb != tcp_write_queue_tail(sk)))
+       if (likely(max_len <= window && skb != tcp_write_queue_tail(meta_sk)))
                return max_len;
 
        needed = min(skb->len, window);
@@ -1467,13 +1547,14 @@
 /* Can at least one segment of SKB be sent right now, according to the
  * congestion window rules?  If so, return how many segments are allowed.
  */
-static inline unsigned int tcp_cwnd_test(const struct tcp_sock *tp,
-                                        const struct sk_buff *skb)
+unsigned int tcp_cwnd_test(const struct tcp_sock *tp,
+                          const struct sk_buff *skb)
 {
        u32 in_flight, cwnd;
 
        /* Don't be strict about the congestion window for the final FIN.  */
-       if ((TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) &&
+       if (skb &&
+           ((TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) || mptcp_is_data_fin(skb)) &&
            tcp_skb_pcount(skb) == 1)
                return 1;
 
@@ -1489,8 +1570,8 @@
  * This must be invoked the first time we consider transmitting
  * SKB onto the wire.
  */
-static int tcp_init_tso_segs(const struct sock *sk, struct sk_buff *skb,
-                            unsigned int mss_now)
+int tcp_init_tso_segs(const struct sock *sk, struct sk_buff *skb,
+                     unsigned int mss_now)
 {
        int tso_segs = tcp_skb_pcount(skb);
 
@@ -1505,8 +1586,8 @@
 /* Return true if the Nagle test allows this packet to be
  * sent now.
  */
-static inline bool tcp_nagle_test(const struct tcp_sock *tp, const struct sk_buff *skb,
-                                 unsigned int cur_mss, int nonagle)
+bool tcp_nagle_test(const struct tcp_sock *tp, const struct sk_buff *skb,
+                   unsigned int cur_mss, int nonagle)
 {
        /* Nagle rule does not apply to frames, which sit in the middle of the
         * write_queue (they have no chances to get new data).
@@ -1518,7 +1599,8 @@
                return true;
 
        /* Don't use the nagle rule for urgent data (or for the final FIN). */
-       if (tcp_urg_mode(tp) || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN))
+       if (tcp_urg_mode(tp) || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) ||
+           mptcp_is_data_fin(skb))
                return true;
 
        if (!tcp_nagle_check(skb->len < cur_mss, tp, cur_mss, nonagle))
@@ -1528,9 +1610,8 @@
 }
 
 /* Does at least the first segment of SKB fit into the send window? */
-static bool tcp_snd_wnd_test(const struct tcp_sock *tp,
-                            const struct sk_buff *skb,
-                            unsigned int cur_mss)
+bool tcp_snd_wnd_test(const struct tcp_sock *tp, const struct sk_buff *skb,
+                     unsigned int cur_mss)
 {
        u32 end_seq = TCP_SKB_CB(skb)->end_seq;
 
@@ -1549,14 +1630,16 @@
 {
        const struct tcp_sock *tp = tcp_sk(sk);
        unsigned int cwnd_quota;
+       const struct sock *meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
+       const struct tcp_sock *meta_tp = tcp_sk(meta_sk);
 
-       tcp_init_tso_segs(sk, skb, cur_mss);
+       tcp_init_tso_segs(meta_sk, skb, cur_mss);
 
-       if (!tcp_nagle_test(tp, skb, cur_mss, nonagle))
+       if (!tcp_nagle_test(meta_tp, skb, cur_mss, nonagle))
                return 0;
 
        cwnd_quota = tcp_cwnd_test(tp, skb);
-       if (cwnd_quota && !tcp_snd_wnd_test(tp, skb, cur_mss))
+       if (cwnd_quota && !tcp_snd_wnd_test(meta_tp, skb, cur_mss))
                cwnd_quota = 0;
 
        return cwnd_quota;
@@ -1566,12 +1649,16 @@
 bool tcp_may_send_now(struct sock *sk)
 {
        const struct tcp_sock *tp = tcp_sk(sk);
-       struct sk_buff *skb = tcp_send_head(sk);
+       struct sk_buff *skb;
+       const struct sock *meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
+       const struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+
+       skb = tcp_send_head(meta_sk);
 
        return skb &&
                tcp_snd_test(sk, skb, tcp_current_mss(sk),
-                            (tcp_skb_is_last(sk, skb) ?
-                             tp->nonagle : TCP_NAGLE_PUSH));
+                            (tcp_skb_is_last(meta_sk, skb) ?
+                             meta_tp->nonagle : TCP_NAGLE_PUSH));
 }
 
 /* Trim TSO SKB to LEN bytes, put the remaining data into a new packet
@@ -1588,6 +1675,9 @@
        int nlen = skb->len - len;
        u8 flags;
 
+       if (tcp_sk(sk)->mpc && mptcp_is_data_seq(skb))
+               mptso_fragment(sk, skb, len, mss_now, gfp, 0);
+
        /* All of a TSO frame must be composed of paged data.  */
        if (skb->len != skb->data_len)
                return tcp_fragment(sk, skb, len, mss_now);
@@ -1633,29 +1723,39 @@
  *
  * This algorithm is from John Heffner.
  */
-static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
+bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
        const struct inet_connection_sock *icsk = inet_csk(sk);
        u32 send_win, cong_win, limit, in_flight;
        int win_divisor;
 
-       if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
+       if ((TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) || mptcp_is_data_fin(skb))
                goto send_now;
 
        if (icsk->icsk_ca_state != TCP_CA_Open)
                goto send_now;
 
        /* Defer for less than two clock ticks. */
-       if (tp->tso_deferred &&
-           (((u32)jiffies << 1) >> 1) - (tp->tso_deferred >> 1) > 1)
+       if (meta_tp->tso_deferred &&
+           (((u32)jiffies << 1) >> 1) - (meta_tp->tso_deferred >> 1) > 1)
                goto send_now;
 
        in_flight = tcp_packets_in_flight(tp);
 
        BUG_ON(tcp_skb_pcount(skb) <= 1 || (tp->snd_cwnd <= in_flight));
 
-       send_win = tcp_wnd_end(tp) - TCP_SKB_CB(skb)->seq;
+       if (!tp->mpc)
+               send_win = tcp_wnd_end(tp) - TCP_SKB_CB(skb)->seq;
+       else
+               /* We need to evaluate the available space in the sending window
+                * at the subflow level. However, the subflow seq has not yet
+                * been set. Nevertheless we know that the caller will set it to
+                * write_seq.
+                */
+               send_win = tcp_wnd_end(tp) - tp->write_seq;
 
        /* From in_flight test above, we know that cwnd > in_flight.  */
        cong_win = (tp->snd_cwnd - in_flight) * tp->mss_cache;
@@ -1668,7 +1768,7 @@
                goto send_now;
 
        /* Middle in queue won't get any more data, full sendable already? */
-       if ((skb != tcp_write_queue_tail(sk)) && (limit >= skb->len))
+       if ((skb != tcp_write_queue_tail(meta_sk)) && (limit >= skb->len))
                goto send_now;
 
        win_divisor = ACCESS_ONCE(sysctl_tcp_tso_win_divisor);
@@ -1694,13 +1794,13 @@
        /* Ok, it looks like it is advisable to defer.
         * Do not rearm the timer if already set to not break TCP ACK clocking.
         */
-       if (!tp->tso_deferred)
-               tp->tso_deferred = 1 | (jiffies << 1);
+       if (!meta_tp->tso_deferred)
+               meta_tp->tso_deferred = 1 | (jiffies << 1);
 
        return true;
 
 send_now:
-       tp->tso_deferred = 0;
+       meta_tp->tso_deferred = 0;
        return false;
 }
 
@@ -1713,7 +1813,7 @@
  *         1 if a probe was sent,
  *         -1 otherwise
  */
-static int tcp_mtu_probe(struct sock *sk)
+int tcp_mtu_probe(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct inet_connection_sock *icsk = inet_csk(sk);
@@ -1858,6 +1958,9 @@
        int cwnd_quota;
        int result;
 
+       if (is_meta_sk(sk))
+               return mptcp_write_xmit(sk, mss_now, nonagle, push_one, gfp);
+
        sent_pkts = 0;
 
        if (!push_one) {
@@ -2314,6 +2417,10 @@
        if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
                return;
 
+       /* Currently not supported for MPTCP - but it should be possible */
+       if (tp->mpc)
+               return;
+
        tcp_for_write_queue_from_safe(skb, tmp, sk) {
                if (!tcp_can_collapse(sk, skb))
                        break;
@@ -2411,10 +2518,26 @@
         */
        if (unlikely((NET_IP_ALIGN && ((unsigned long)skb->data & 3)) ||
                     skb_headroom(skb) >= 0xFFFF)) {
-               struct sk_buff *nskb = __pskb_copy(skb, MAX_TCP_HEADER,
-                                                  GFP_ATOMIC);
+               struct sk_buff *nskb;
+
+               if (mptcp_is_data_seq(skb))
+                       skb_push(skb, MPTCP_SUB_LEN_DSS_ALIGN +
+                                     MPTCP_SUB_LEN_ACK_ALIGN +
+                                     MPTCP_SUB_LEN_SEQ_ALIGN);
+
+               nskb = __pskb_copy(skb, MAX_TCP_HEADER, GFP_ATOMIC);
+
+               if (mptcp_is_data_seq(skb)) {
+                       skb_pull(skb, MPTCP_SUB_LEN_DSS_ALIGN +
+                                     MPTCP_SUB_LEN_ACK_ALIGN +
+                                     MPTCP_SUB_LEN_SEQ_ALIGN);
+                       if (nskb)
+                               skb_pull(nskb, MPTCP_SUB_LEN_DSS_ALIGN +
+                                              MPTCP_SUB_LEN_ACK_ALIGN +
+                                              MPTCP_SUB_LEN_SEQ_ALIGN);
+               }
                err = nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
-                            -ENOBUFS;
+                             -ENOBUFS;
        } else {
                err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
        }
@@ -2665,6 +2788,11 @@
 {
        struct sk_buff *skb;
 
+       if (is_meta_sk(sk)) {
+               mptcp_send_active_reset(sk, priority);
+               return;
+       }
+
        /* NOTE: No TCP options attached and we never retransmit this. */
        skb = alloc_skb(MAX_TCP_HEADER, priority);
        if (!skb) {
@@ -2767,14 +2895,14 @@
                    (req->window_clamp > tcp_full_space(sk) || req->window_clamp == 0))
                        req->window_clamp = tcp_full_space(sk);
 
-               /* tcp_full_space because it is guaranteed to be the first packet */
-               tcp_select_initial_window(tcp_full_space(sk),
-                       mss - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0),
+               tp->select_initial_window(tcp_full_space(sk),
+                       mss - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0) -
+                       (tcp_rsk(req)->saw_mpc ? MPTCP_SUB_LEN_DSM_ALIGN : 0),
                        &req->rcv_wnd,
                        &req->window_clamp,
                        ireq->wscale_ok,
                        &rcv_wscale,
-                       dst_metric(dst, RTAX_INITRWND));
+                       dst_metric(dst, RTAX_INITRWND), sk);
                ireq->rcv_wscale = rcv_wscale;
        }
 
@@ -2810,7 +2938,7 @@
 
        /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */
        th->window = htons(min(req->rcv_wnd, 65535U));
-       tcp_options_write((__be32 *)(th + 1), tp, &opts);
+       tcp_options_write((__be32 *)(th + 1), tp, &opts, skb);
        th->doff = (tcp_header_size >> 2);
        TCP_ADD_STATS(sock_net(sk), TCP_MIB_OUTSEGS, tcp_skb_pcount(skb));
 
@@ -2866,13 +2994,13 @@
            (tp->window_clamp > tcp_full_space(sk) || tp->window_clamp == 0))
                tp->window_clamp = tcp_full_space(sk);
 
-       tcp_select_initial_window(tcp_full_space(sk),
+       tp->select_initial_window(tcp_full_space(sk),
                                  tp->advmss - (tp->rx_opt.ts_recent_stamp ? tp->tcp_header_len - sizeof(struct tcphdr) : 0),
                                  &tp->rcv_wnd,
                                  &tp->window_clamp,
                                  sysctl_tcp_window_scaling,
                                  &rcv_wscale,
-                                 dst_metric(dst, RTAX_INITRWND));
+                                 dst_metric(dst, RTAX_INITRWND), sk);
 
        tp->rx_opt.rcv_wscale = rcv_wscale;
        tp->rcv_ssthresh = tp->rcv_wnd;
@@ -2896,6 +3024,38 @@
        inet_csk(sk)->icsk_rto = TCP_TIMEOUT_INIT;
        inet_csk(sk)->icsk_retransmits = 0;
        tcp_clear_retrans(tp);
+
+#ifdef CONFIG_MPTCP
+       if (sysctl_mptcp_enabled && mptcp_doit(sk)) {
+               if (is_master_tp(tp)) {
+                       tp->request_mptcp = 1;
+                       mptcp_connect_init(sk);
+               } else if (tp->mptcp) {
+                       struct inet_sock *inet  = inet_sk(sk);
+
+                       tp->mptcp->snt_isn      = tp->write_seq;
+                       tp->mptcp->init_rcv_wnd = tp->rcv_wnd;
+
+                       /* Set nonce for new subflows */
+                       if (sk->sk_family == AF_INET)
+                               tp->mptcp->mptcp_loc_nonce = mptcp_v4_get_nonce(
+                                                       inet->inet_saddr,
+                                                       inet->inet_daddr,
+                                                       inet->inet_sport,
+                                                       inet->inet_dport,
+                                                       tp->write_seq);
+#if IS_ENABLED(CONFIG_IPV6)
+                       else
+                               tp->mptcp->mptcp_loc_nonce = mptcp_v6_get_nonce(
+                                               inet6_sk(sk)->saddr.s6_addr32,
+                                               sk->sk_v6_daddr.s6_addr32,
+                                               inet->inet_sport,
+                                               inet->inet_dport,
+                                               tp->write_seq);
+#endif
+               }
+       }
+#endif
 }
 
 static void tcp_connect_queue_skb(struct sock *sk, struct sk_buff *skb)
@@ -3131,6 +3291,7 @@
        TCP_SKB_CB(buff)->when = tcp_time_stamp;
        tcp_transmit_skb(sk, buff, 0, sk_gfp_atomic(sk, GFP_ATOMIC));
 }
+EXPORT_SYMBOL(tcp_send_ack);
 
 /* This routine sends a packet with an out of date sequence
  * number. It assumes the other end will try to ack it.
@@ -3143,7 +3304,7 @@
  * one is with SEG.SEQ=SND.UNA to deliver urgent pointer, another is
  * out-of-date with SND.UNA-1 to probe window.
  */
-static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
+int tcp_xmit_probe_skb(struct sock *sk, int urgent)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *skb;
@@ -3181,6 +3342,9 @@
        if (sk->sk_state == TCP_CLOSE)
                return -1;
 
+       if (is_meta_sk(sk))
+               return mptcp_write_wakeup(sk);
+
        if ((skb = tcp_send_head(sk)) != NULL &&
            before(TCP_SKB_CB(skb)->seq, tcp_wnd_end(tp))) {
                int err;
diff -Nur linux-3.14.45.orig/net/ipv4/tcp_timer.c linux-3.14.45/net/ipv4/tcp_timer.c
--- linux-3.14.45.orig/net/ipv4/tcp_timer.c     2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv4/tcp_timer.c  2015-06-24 14:15:48.891862483 +0200
@@ -20,6 +20,7 @@
 
 #include <linux/module.h>
 #include <linux/gfp.h>
+#include <net/mptcp.h>
 #include <net/tcp.h>
 
 int sysctl_tcp_syn_retries __read_mostly = TCP_SYN_RETRIES;
@@ -32,7 +33,7 @@
 int sysctl_tcp_orphan_retries __read_mostly;
 int sysctl_tcp_thin_linear_timeouts __read_mostly;
 
-static void tcp_write_err(struct sock *sk)
+void tcp_write_err(struct sock *sk)
 {
        sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
        sk->sk_error_report(sk);
@@ -124,10 +125,8 @@
  * retransmissions with an initial RTO of TCP_RTO_MIN or TCP_TIMEOUT_INIT if
  * syn_set flag is set.
  */
-static bool retransmits_timed_out(struct sock *sk,
-                                 unsigned int boundary,
-                                 unsigned int timeout,
-                                 bool syn_set)
+bool retransmits_timed_out(struct sock *sk, unsigned int boundary,
+                          unsigned int timeout, bool syn_set)
 {
        unsigned int linear_backoff_thresh, start_ts;
        unsigned int rto_base = syn_set ? TCP_TIMEOUT_INIT : TCP_RTO_MIN;
@@ -153,7 +152,7 @@
 }
 
 /* A write timeout has occurred. Process the after effects. */
-static int tcp_write_timeout(struct sock *sk)
+int tcp_write_timeout(struct sock *sk)
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
@@ -168,6 +167,10 @@
                }
                retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
                syn_set = true;
+               /* Stop retransmitting MP_CAPABLE options in SYN if timed out. */
+               if (tcp_sk(sk)->request_mptcp &&
+                   icsk->icsk_retransmits >= mptcp_sysctl_syn_retries())
+                       tcp_sk(sk)->request_mptcp = 0;
        } else {
                if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) {
                        /* Black hole detection */
@@ -248,18 +251,22 @@
 static void tcp_delack_timer(unsigned long data)
 {
        struct sock *sk = (struct sock *)data;
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
 
-       bh_lock_sock(sk);
-       if (!sock_owned_by_user(sk)) {
+       bh_lock_sock(meta_sk);
+       if (!sock_owned_by_user(meta_sk)) {
                tcp_delack_timer_handler(sk);
        } else {
                inet_csk(sk)->icsk_ack.blocked = 1;
-               NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
+               NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_DELAYEDACKLOCKED);
                /* deleguate our work to tcp_release_cb() */
                if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, &tcp_sk(sk)->tsq_flags))
                        sock_hold(sk);
+               if (tp->mpc)
+                       mptcp_tsq_flags(sk);
        }
-       bh_unlock_sock(sk);
+       bh_unlock_sock(meta_sk);
        sock_put(sk);
 }
 
@@ -421,6 +428,9 @@
 
        tcp_enter_loss(sk, 0);
 
+       if (tp->mpc)
+               mptcp_reinject_data(sk, 1);
+
        if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) {
                /* Retransmission failed because of local congestion,
                 * do not backoff.
@@ -471,6 +481,8 @@
                /* Use normal (exponential) backoff */
                icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX);
        }
+       if (tp->mpc)
+               mptcp_set_rto(sk);
        inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX);
        if (retransmits_timed_out(sk, sysctl_tcp_retries1 + 1, 0, 0))
                __sk_dst_reset(sk);
@@ -502,7 +514,10 @@
                break;
        case ICSK_TIME_RETRANS:
                icsk->icsk_pending = 0;
-               tcp_retransmit_timer(sk);
+               if (is_meta_sk(sk))
+                       mptcp_retransmit_timer(sk);
+               else
+                       tcp_retransmit_timer(sk);
                break;
        case ICSK_TIME_PROBE0:
                icsk->icsk_pending = 0;
@@ -517,16 +532,19 @@
 static void tcp_write_timer(unsigned long data)
 {
        struct sock *sk = (struct sock *)data;
+       struct sock *meta_sk = tcp_sk(sk)->mpc ? mptcp_meta_sk(sk) : sk;
 
-       bh_lock_sock(sk);
-       if (!sock_owned_by_user(sk)) {
+       bh_lock_sock(meta_sk);
+       if (!sock_owned_by_user(meta_sk)) {
                tcp_write_timer_handler(sk);
        } else {
                /* deleguate our work to tcp_release_cb() */
                if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, &tcp_sk(sk)->tsq_flags))
                        sock_hold(sk);
+               if (tcp_sk(sk)->mpc)
+                       mptcp_tsq_flags(sk);
        }
-       bh_unlock_sock(sk);
+       bh_unlock_sock(meta_sk);
        sock_put(sk);
 }
 
@@ -563,11 +581,12 @@
        struct sock *sk = (struct sock *) data;
        struct inet_connection_sock *icsk = inet_csk(sk);
        struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = tp->mpc ? mptcp_meta_sk(sk) : sk;
        u32 elapsed;
 
        /* Only process if socket is not in use. */
-       bh_lock_sock(sk);
-       if (sock_owned_by_user(sk)) {
+       bh_lock_sock(meta_sk);
+       if (sock_owned_by_user(meta_sk)) {
                /* Try again later. */
                inet_csk_reset_keepalive_timer (sk, HZ/20);
                goto out;
@@ -578,6 +597,29 @@
                goto out;
        }
 
+       if (tp->send_mp_fclose) {
+               /* MUST do this before tcp_write_timeout, because retrans_stamp
+                * may have been set to 0 in another part while we are
+                * retransmitting MP_FASTCLOSE. Then, we would crash, because
+                * retransmits_timed_out accesses the meta-write-queue.
+                *
+                * We make sure that the timestamp is != 0.
+                */
+               if (!tp->retrans_stamp)
+                       tp->retrans_stamp = tcp_time_stamp ? : 1;
+
+               if (tcp_write_timeout(sk))
+                       goto out;
+
+               tcp_send_ack(sk);
+               icsk->icsk_backoff++;
+               icsk->icsk_retransmits++;
+
+               icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX);
+               elapsed = icsk->icsk_rto;
+               goto resched;
+       }
+
        if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) {
                if (tp->linger2 >= 0) {
                        const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN;
@@ -639,7 +681,7 @@
        tcp_done(sk);
 
 out:
-       bh_unlock_sock(sk);
+       bh_unlock_sock(meta_sk);
        sock_put(sk);
 }
 
diff -Nur linux-3.14.45.orig/net/ipv6/addrconf.c linux-3.14.45/net/ipv6/addrconf.c
--- linux-3.14.45.orig/net/ipv6/addrconf.c      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv6/addrconf.c   2015-06-24 14:15:48.891862483 +0200
@@ -765,6 +765,7 @@
 
        kfree_rcu(ifp, rcu);
 }
+EXPORT_SYMBOL(inet6_ifa_finish_destroy);
 
 static void
 ipv6_link_dev_addr(struct inet6_dev *idev, struct inet6_ifaddr *ifp)
diff -Nur linux-3.14.45.orig/net/ipv6/af_inet6.c linux-3.14.45/net/ipv6/af_inet6.c
--- linux-3.14.45.orig/net/ipv6/af_inet6.c      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv6/af_inet6.c   2015-06-24 14:15:48.891862483 +0200
@@ -97,8 +97,7 @@
        return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
 }
 
-static int inet6_create(struct net *net, struct socket *sock, int protocol,
-                       int kern)
+int inet6_create(struct net *net, struct socket *sock, int protocol, int kern)
 {
        struct inet_sock *inet;
        struct ipv6_pinfo *np;
diff -Nur linux-3.14.45.orig/net/ipv6/inet6_connection_sock.c linux-3.14.45/net/ipv6/inet6_connection_sock.c
--- linux-3.14.45.orig/net/ipv6/inet6_connection_sock.c 2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv6/inet6_connection_sock.c      2015-06-24 14:15:48.891862483 +0200
@@ -96,8 +96,8 @@
 /*
  * request_sock (formerly open request) hash tables.
  */
-static u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport,
-                          const u32 rnd, const u32 synq_hsize)
+u32 inet6_synq_hash(const struct in6_addr *raddr, const __be16 rport,
+                   const u32 rnd, const u32 synq_hsize)
 {
        u32 c;
 
diff -Nur linux-3.14.45.orig/net/ipv6/syncookies.c linux-3.14.45/net/ipv6/syncookies.c
--- linux-3.14.45.orig/net/ipv6/syncookies.c    2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv6/syncookies.c 2015-06-24 14:15:48.891862483 +0200
@@ -181,7 +181,7 @@
 
        /* check for timestamp cookie support */
        memset(&tcp_opt, 0, sizeof(tcp_opt));
-       tcp_parse_options(skb, &tcp_opt, 0, NULL);
+       tcp_parse_options(skb, &tcp_opt, NULL, 0, NULL);
 
        if (!cookie_check_timestamp(&tcp_opt, sock_net(sk), &ecn_ok))
                goto out;
@@ -253,10 +253,10 @@
        }
 
        req->window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW);
-       tcp_select_initial_window(tcp_full_space(sk), req->mss,
+       tp->select_initial_window(tcp_full_space(sk), req->mss,
                                  &req->rcv_wnd, &req->window_clamp,
                                  ireq->wscale_ok, &rcv_wscale,
-                                 dst_metric(dst, RTAX_INITRWND));
+                                 dst_metric(dst, RTAX_INITRWND), sk);
 
        ireq->rcv_wscale = rcv_wscale;
 
diff -Nur linux-3.14.45.orig/net/ipv6/tcp_ipv6.c linux-3.14.45/net/ipv6/tcp_ipv6.c
--- linux-3.14.45.orig/net/ipv6/tcp_ipv6.c      2015-06-23 02:01:36.000000000 +0200
+++ linux-3.14.45/net/ipv6/tcp_ipv6.c   2015-06-24 14:44:57.517799806 +0200
@@ -63,6 +63,8 @@
 #include <net/inet_common.h>
 #include <net/secure_seq.h>
 #include <net/tcp_memcontrol.h>
+#include <net/mptcp.h>
+#include <net/mptcp_v6.h>
 #include <net/busy_poll.h>
 
 #include <asm/uaccess.h>
@@ -73,14 +75,6 @@
 #include <linux/crypto.h>
 #include <linux/scatterlist.h>
 
-static void    tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
-static void    tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
-                                     struct request_sock *req);
-
-static int     tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
-
-static const struct inet_connection_sock_af_ops ipv6_mapped;
-static const struct inet_connection_sock_af_ops ipv6_specific;
 #ifdef CONFIG_TCP_MD5SIG
 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
@@ -92,7 +86,7 @@
 }
 #endif
 
-static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
+void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
 {
        struct dst_entry *dst = skb_dst(skb);
        const struct rt6_info *rt = (const struct rt6_info *)dst;
@@ -104,7 +98,7 @@
                inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum;
 }
 
-static void tcp_v6_hash(struct sock *sk)
+void tcp_v6_hash(struct sock *sk)
 {
        if (sk->sk_state != TCP_CLOSE) {
                if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
@@ -117,7 +111,7 @@
        }
 }
 
-static __u32 tcp_v6_init_sequence(const struct sk_buff *skb)
+__u32 tcp_v6_init_sequence(const struct sk_buff *skb)
 {
        return secure_tcpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
                                            ipv6_hdr(skb)->saddr.s6_addr32,
@@ -125,7 +119,7 @@
                                            tcp_hdr(skb)->source);
 }
 
-static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
+int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
                          int addr_len)
 {
        struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
@@ -339,7 +333,7 @@
        const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
        const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
        struct ipv6_pinfo *np;
-       struct sock *sk;
+       struct sock *sk, *meta_sk;
        int err;
        struct tcp_sock *tp;
        __u32 seq;
@@ -359,8 +353,14 @@
                return;
        }
 
-       bh_lock_sock(sk);
-       if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
+       tp = tcp_sk(sk);
+       if (tp->mpc)
+               meta_sk = mptcp_meta_sk(sk);
+       else
+               meta_sk = sk;
+
+       bh_lock_sock(meta_sk);
+       if (sock_owned_by_user(meta_sk) && type != ICMPV6_PKT_TOOBIG)
                NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
 
        if (sk->sk_state == TCP_CLOSE)
@@ -371,7 +371,6 @@
                goto out;
        }
 
-       tp = tcp_sk(sk);
        seq = ntohl(th->seq);
        if (sk->sk_state != TCP_LISTEN &&
            !between(seq, tp->snd_una, tp->snd_nxt)) {
@@ -401,11 +400,15 @@
                        goto out;
 
                tp->mtu_info = ntohl(info);
-               if (!sock_owned_by_user(sk))
+               if (!sock_owned_by_user(meta_sk))
                        tcp_v6_mtu_reduced(sk);
-               else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
+               else {
+                       if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
                                           &tp->tsq_flags))
-                       sock_hold(sk);
+                               sock_hold(sk);
+                       if (tp->mpc)
+                               mptcp_tsq_flags(sk);
+               }
                goto out;
        }
 
@@ -415,7 +418,7 @@
        switch (sk->sk_state) {
                struct request_sock *req, **prev;
        case TCP_LISTEN:
-               if (sock_owned_by_user(sk))
+               if (sock_owned_by_user(meta_sk))
                        goto out;
 
                req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
@@ -440,7 +443,7 @@
        case TCP_SYN_SENT:
        case TCP_SYN_RECV:  /* Cannot happen.
                               It can, it SYNs are crossed. --ANK */
-               if (!sock_owned_by_user(sk)) {
+               if (!sock_owned_by_user(meta_sk)) {
                        sk->sk_err = err;
                        sk->sk_error_report(sk);                /* Wake people up to see the error (see connect in sock.c) */
 
@@ -450,22 +453,22 @@
                goto out;
        }
 
-       if (!sock_owned_by_user(sk) && np->recverr) {
+       if (!sock_owned_by_user(meta_sk) && np->recverr) {
                sk->sk_err = err;
                sk->sk_error_report(sk);
        } else
                sk->sk_err_soft = err;
 
 out:
-       bh_unlock_sock(sk);
+       bh_unlock_sock(meta_sk);
        sock_put(sk);
 }
 
 
-static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
-                             struct flowi6 *fl6,
-                             struct request_sock *req,
-                             u16 queue_mapping)
+int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
+                      struct flowi6 *fl6,
+                      struct request_sock *req,
+                      u16 queue_mapping)
 {
        struct inet_request_sock *ireq = inet_rsk(req);
        struct ipv6_pinfo *np = inet6_sk(sk);
@@ -495,7 +498,7 @@
        return err;
 }
 
-static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req)
+int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req)
 {
        struct flowi6 fl6;
        int res;
@@ -506,7 +509,7 @@
        return res;
 }
 
-static void tcp_v6_reqsk_destructor(struct request_sock *req)
+void tcp_v6_reqsk_destructor(struct request_sock *req)
 {
        kfree_skb(inet_rsk(req)->pktopts);
 }
@@ -719,16 +722,16 @@
 };
 
 #ifdef CONFIG_TCP_MD5SIG
-static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
+const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
        .md5_lookup     =       tcp_v6_reqsk_md5_lookup,
        .calc_md5_hash  =       tcp_v6_md5_hash_skb,
 };
 #endif
 
-static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
-                                u32 tsval, u32 tsecr,
+static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack,
+                                u32 data_ack, u32 win, u32 tsval, u32 tsecr,
                                 struct tcp_md5sig_key *key, int rst, u8 tclass,
-                                u32 label)
+                                u32 label, int mptcp)
 {
        const struct tcphdr *th = tcp_hdr(skb);
        struct tcphdr *t1;
@@ -746,7 +749,10 @@
        if (key)
                tot_len += TCPOLEN_MD5SIG_ALIGNED;
 #endif
-
+#ifdef CONFIG_MPTCP
+       if (mptcp)
+               tot_len += MPTCP_SUB_LEN_DSS + MPTCP_SUB_LEN_ACK;
+#endif
        buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
                         GFP_ATOMIC);
        if (buff == NULL)
@@ -784,6 +790,17 @@
                tcp_v6_md5_hash_hdr((__u8 *)topt, key,
                                    &ipv6_hdr(skb)->saddr,
                                    &ipv6_hdr(skb)->daddr, t1);
+               topt += 4;
+       }
+#endif
+#ifdef CONFIG_MPTCP
+       if (mptcp) {
+               /* Construction of 32-bit data_ack */
+               *topt++ = htonl((TCPOPT_MPTCP << 24) |
+                               ((MPTCP_SUB_LEN_DSS + MPTCP_SUB_LEN_ACK) << 16) |
+                               (0x20 << 8) |
+                               (0x01));
+               *topt++ = htonl(data_ack);
        }
 #endif
 
@@ -821,7 +838,7 @@
        kfree_skb(buff);
 }
 
-static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
+void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
 {
        const struct tcphdr *th = tcp_hdr(skb);
        u32 seq = 0, ack_seq = 0;
@@ -876,7 +893,7 @@
                ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
                          (th->doff << 2);
 
-       tcp_v6_send_response(skb, seq, ack_seq, 0, 0, 0, key, 1, 0, 0);
+       tcp_v6_send_response(skb, seq, ack_seq, 0, 0, 0, 0, key, 1, 0, 0, 0);
 
 #ifdef CONFIG_TCP_MD5SIG
 release_sk1:
@@ -887,40 +904,48 @@
 #endif
 }
 
-static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
+static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 data_ack,
                            u32 win, u32 tsval, u32 tsecr,
-                           struct tcp_md5sig_key *key, u8 tclass,
-                           u32 label)
+                           struct tcp_md5sig_key *key, u8 tclass, u32 label,
+                           int mptcp)
 {
        tcp_v6_send_response(skb, seq, ack, win, tsval, tsecr, key, 0, tclass,
-                            label);
+                            label, mptcp);
 }
 
 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 {
        struct inet_timewait_sock *tw = inet_twsk(sk);
        struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
+       u32 data_ack = 0;
+       int mptcp = 0;
+ 
+       if (tcptw->mptcp_tw && tcptw->mptcp_tw->meta_tw) {
+               data_ack = (u32)tcptw->mptcp_tw->rcv_nxt;
+               mptcp = 1;
+       }
 
        tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
+                       data_ack,
                        tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
                        tcp_time_stamp + tcptw->tw_ts_offset,
                        tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
-                       tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
+                       tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), mptcp);
 
        inet_twsk_put(tw);
 }
 
-static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
                                  struct request_sock *req)
 {
        tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1,
-                       req->rcv_wnd, tcp_time_stamp, req->ts_recent,
+                       0, req->rcv_wnd, tcp_time_stamp, req->ts_recent,
                        tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
-                       0, 0);
+                       0, 0, 0);
 }
 
 
-static struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb)
+struct sock *tcp_v6_hnd_req(struct sock *sk, struct sk_buff *skb)
 {
        struct request_sock *req, **prev;
        const struct tcphdr *th = tcp_hdr(skb);
@@ -939,7 +964,13 @@
 
        if (nsk) {
                if (nsk->sk_state != TCP_TIME_WAIT) {
+                       /* Don't lock again the meta-sk. It has been locked
+                        * before mptcp_v6_do_rcv.
+                        */
+                       if (tcp_sk(nsk)->mpc && !is_meta_sk(sk))
+                               bh_lock_sock(mptcp_meta_sk(nsk));
                        bh_lock_sock(nsk);
+
                        return nsk;
                }
                inet_twsk_put(inet_twsk(nsk));
@@ -959,6 +990,7 @@
 static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_options_received tmp_opt;
+       struct mptcp_options_received mopt;
        struct request_sock *req;
        struct inet_request_sock *ireq;
        struct ipv6_pinfo *np = inet6_sk(sk);
@@ -971,6 +1003,23 @@
        if (skb->protocol == htons(ETH_P_IP))
                return tcp_v4_conn_request(sk, skb);
 
+       tcp_clear_options(&tmp_opt);
+       tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
+       tmp_opt.user_mss = tp->rx_opt.user_mss;
+       mptcp_init_mp_opt(&mopt);
+       tcp_parse_options(skb, &tmp_opt, &mopt, 0, NULL);
+
+#ifdef CONFIG_MPTCP
+       /*MPTCP structures not initialized, so return error */
+       if (mptcp_init_failed)
+               mptcp_init_mp_opt(&mopt);
+
+       if (mopt.is_mp_join)
+               return mptcp_do_join_short(skb, &mopt, &tmp_opt, sock_net(sk));
+       if (mopt.drop_me)
+               goto drop;
+#endif
+
        if (!ipv6_unicast_destination(skb))
                goto drop;
 
@@ -986,7 +1035,22 @@
                goto drop;
        }
 
-       req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
+#ifdef CONFIG_MPTCP
+       if (sysctl_mptcp_enabled == MPTCP_APP && !tp->mptcp_enabled)
+               mopt.saw_mpc = 0;
+       if (mopt.saw_mpc && !want_cookie) {
+               req = inet6_reqsk_alloc(&mptcp6_request_sock_ops);
+
+               if (req == NULL)
+                       goto drop;
+
+               mptcp_rsk(req)->mpcb = NULL;
+               mptcp_rsk(req)->dss_csum = mopt.dss_csum;
+               mptcp_rsk(req)->collide_tk.pprev = NULL;
+       } else
+#endif
+               req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
+
        if (req == NULL)
                goto drop;
 
@@ -994,17 +1058,15 @@
        tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
 #endif
 
-       tcp_clear_options(&tmp_opt);
-       tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
-       tmp_opt.user_mss = tp->rx_opt.user_mss;
-       tcp_parse_options(skb, &tmp_opt, 0, NULL);
-
        if (want_cookie && !tmp_opt.saw_tstamp)
                tcp_clear_options(&tmp_opt);
 
        tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
        tcp_openreq_init(req, &tmp_opt, skb);
 
+       if (mopt.saw_mpc && !want_cookie)
+               mptcp_reqsk_new_mptcp(req, &tmp_opt, &mopt, skb);
+
        ireq = inet_rsk(req);
        ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
        ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
@@ -1094,9 +1156,9 @@
        return 0; /* don't send reset */
 }
 
-static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
-                                        struct request_sock *req,
-                                        struct dst_entry *dst)
+struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
+                                 struct request_sock *req,
+                                 struct dst_entry *dst)
 {
        struct inet_request_sock *ireq;
        struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
@@ -1317,7 +1379,7 @@
  * This is because we cannot sleep with the original spinlock
  * held.
  */
-static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
+int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 {
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct tcp_sock *tp;
@@ -1339,6 +1401,9 @@
                goto discard;
 #endif
 
+       if (is_meta_sk(sk))
+               return mptcp_v6_do_rcv(sk, skb);
+
        if (sk_filter(sk, skb))
                goto discard;
 
@@ -1460,7 +1525,7 @@
 {
        const struct tcphdr *th;
        const struct ipv6hdr *hdr;
-       struct sock *sk;
+       struct sock *sk, *meta_sk = NULL;
        int ret;
        struct net *net = dev_net(skb->dev);
 
@@ -1491,18 +1556,43 @@
        TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
                                    skb->len - th->doff*4);
        TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
+#ifdef CONFIG_MPTCP
+       TCP_SKB_CB(skb)->mptcp_flags = 0;
+       TCP_SKB_CB(skb)->dss_off = 0;
+#endif
        TCP_SKB_CB(skb)->when = 0;
        TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
        TCP_SKB_CB(skb)->sacked = 0;
 
        sk = __inet6_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
-       if (!sk)
-               goto no_tcp_socket;
 
 process:
-       if (sk->sk_state == TCP_TIME_WAIT)
+       if (sk && sk->sk_state == TCP_TIME_WAIT)
                goto do_time_wait;
 
+#ifdef CONFIG_MPTCP
+       if (!sk && th->syn && !th->ack) {
+               int ret = mptcp_lookup_join(skb, NULL);
+
+               if (ret < 0) {
+                       tcp_v6_send_reset(NULL, skb);
+                       goto discard_it;
+               } else if (ret > 0) {
+                       return 0;
+               }
+       }
+
+       /* Is there a pending request sock for this segment ? */
+       if ((!sk || sk->sk_state == TCP_LISTEN) && mptcp_check_req(skb, net)) {
+               if (sk)
+                       sock_put(sk);
+               return 0;
+       }
+#endif
+
+       if (!sk)
+               goto no_tcp_socket;
+
        if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {
                NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
                goto discard_and_relse;
@@ -1517,11 +1607,21 @@
        sk_mark_napi_id(sk, skb);
        skb->dev = NULL;
 
-       bh_lock_sock_nested(sk);
+       if (tcp_sk(sk)->mpc) {
+               meta_sk = mptcp_meta_sk(sk);
+
+               bh_lock_sock_nested(meta_sk);
+               if (sock_owned_by_user(meta_sk))
+                       skb->sk = sk;
+       } else {
+               meta_sk = sk;
+               bh_lock_sock_nested(sk);
+       }
+
        ret = 0;
-       if (!sock_owned_by_user(sk)) {
+       if (!sock_owned_by_user(meta_sk)) {
 #ifdef CONFIG_NET_DMA
-               struct tcp_sock *tp = tcp_sk(sk);
+               struct tcp_sock *tp = tcp_sk(meta_sk);
                if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
                        tp->ucopy.dma_chan = net_dma_find_channel();
                if (tp->ucopy.dma_chan)
@@ -1529,16 +1629,17 @@
                else
 #endif
                {
-                       if (!tcp_prequeue(sk, skb))
+                       if (!tcp_prequeue(meta_sk, skb))
                                ret = tcp_v6_do_rcv(sk, skb);
                }
-       } else if (unlikely(sk_add_backlog(sk, skb,
-                                          sk->sk_rcvbuf + sk->sk_sndbuf))) {
-               bh_unlock_sock(sk);
+       } else if (unlikely(sk_add_backlog(meta_sk, skb,
+                                          meta_sk->sk_rcvbuf + meta_sk->sk_sndbuf))) {
+               bh_unlock_sock(meta_sk);
                NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
                goto discard_and_relse;
        }
-       bh_unlock_sock(sk);
+
+       bh_unlock_sock(meta_sk);
 
        sock_put(sk);
        return ret ? -1 : 0;
@@ -1595,6 +1696,18 @@
                        sk = sk2;
                        goto process;
                }
+#ifdef CONFIG_MPTCP
+               if (th->syn && !th->ack) {
+                       int ret = mptcp_lookup_join(skb, inet_twsk(sk));
+
+                       if (ret < 0) {
+                               tcp_v6_send_reset(NULL, skb);
+                               goto discard_it;
+                       } else if (ret > 0) {
+                               return 0;
+                       }
+               }
+#endif
                /* Fall through to ACK */
        }
        case TCP_TW_ACK:
@@ -1644,13 +1757,13 @@
        }
 }
 
-static struct timewait_sock_ops tcp6_timewait_sock_ops = {
+struct timewait_sock_ops tcp6_timewait_sock_ops = {
        .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
        .twsk_unique    = tcp_twsk_unique,
        .twsk_destructor= tcp_twsk_destructor,
 };
 
-static const struct inet_connection_sock_af_ops ipv6_specific = {
+const struct inet_connection_sock_af_ops ipv6_specific = {
        .queue_xmit        = inet6_csk_xmit,
        .send_check        = tcp_v6_send_check,
        .rebuild_header    = inet6_sk_rebuild_header,
@@ -1683,7 +1796,7 @@
  *     TCP over IPv4 via INET6 API
  */
 
-static const struct inet_connection_sock_af_ops ipv6_mapped = {
+const struct inet_connection_sock_af_ops ipv6_mapped = {
        .queue_xmit        = ip_queue_xmit,
        .send_check        = tcp_v4_send_check,
        .rebuild_header    = inet_sk_rebuild_header,
@@ -1729,7 +1842,7 @@
        return 0;
 }
 
-static void tcp_v6_destroy_sock(struct sock *sk)
+void tcp_v6_destroy_sock(struct sock *sk)
 {
        tcp_v4_destroy_sock(sk);
        inet6_destroy_sock(sk);
diff -Nur linux-3.14.45.orig/net/mptcp/Kconfig linux-3.14.45/net/mptcp/Kconfig
--- linux-3.14.45.orig/net/mptcp/Kconfig        1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/Kconfig     2015-06-24 14:15:48.891862483 +0200
@@ -0,0 +1,58 @@
+#
+# MPTCP configuration
+#
+config MPTCP
+        bool "MPTCP protocol"
+        depends on (IPV6=y || IPV6=n)
+        ---help---
+          This replaces the normal TCP stack with a Multipath TCP stack,
+          able to use several paths at once.
+
+menuconfig MPTCP_PM_ADVANCED
+       bool "MPTCP: advanced path-manager control"
+       depends on MPTCP=y
+       ---help---
+         Support for selection of different path-managers. You should choose 'Y' here,
+         because otherwise you will not actively create new MPTCP-subflows.
+
+if MPTCP_PM_ADVANCED
+
+config MPTCP_FULLMESH
+       tristate "MPTCP Full-Mesh Path-Manager"
+       depends on MPTCP=y
+       ---help---
+         This path-management module will create a full-mesh among all IP-addresses.
+
+config MPTCP_NDIFFPORTS
+       tristate "MPTCP ndiff-ports"
+       depends on MPTCP=y
+       ---help---
+         This path-management module will create multiple subflows between the same
+         pair of IP-addresses, modifying the source-port. You can set the number
+         of subflows via the mptcp_ndiffports-sysctl.
+
+choice
+       prompt "Default MPTCP Path-Manager"
+       default DEFAULT
+       help
+         Select the Path-Manager of your choice
+
+       config DEFAULT_FULLMESH
+               bool "Full mesh" if MPTCP_FULLMESH=y
+
+       config DEFAULT_NDIFFPORTS
+               bool "ndiff-ports" if MPTCP_NDIFFPORTS=y
+
+       config DEFAULT_DUMMY
+               bool "Default"
+
+endchoice
+
+endif
+
+config DEFAULT_MPTCP_PM
+       string
+       default "default" if DEFAULT_DUMMY
+       default "fullmesh" if DEFAULT_FULLMESH 
+       default "ndiffports" if DEFAULT_NDIFFPORTS
+       default "default"
diff -Nur linux-3.14.45.orig/net/mptcp/Makefile linux-3.14.45/net/mptcp/Makefile
--- linux-3.14.45.orig/net/mptcp/Makefile       1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/Makefile    2015-06-24 14:15:48.891862483 +0200
@@ -0,0 +1,18 @@
+#
+## Makefile for MultiPath TCP support code.
+#
+#
+
+obj-$(CONFIG_MPTCP) += mptcp.o
+
+mptcp-y := mptcp_ctrl.o mptcp_ipv4.o mptcp_ofo_queue.o mptcp_pm.o \
+          mptcp_output.o mptcp_input.o
+
+obj-$(CONFIG_TCP_CONG_COUPLED) += mptcp_coupled.o
+obj-$(CONFIG_TCP_CONG_OLIA) += mptcp_olia.o
+obj-$(CONFIG_TCP_CONG_WVEGAS) += mptcp_wvegas.o
+obj-$(CONFIG_MPTCP_FULLMESH) += mptcp_fullmesh.o
+obj-$(CONFIG_MPTCP_NDIFFPORTS) += mptcp_ndiffports.o
+
+mptcp-$(subst m,y,$(CONFIG_IPV6)) += mptcp_ipv6.o
+
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_coupled.c linux-3.14.45/net/mptcp/mptcp_coupled.c
--- linux-3.14.45.orig/net/mptcp/mptcp_coupled.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_coupled.c     2015-06-24 14:15:48.891862483 +0200
@@ -0,0 +1,273 @@
+/*
+ *     MPTCP implementation - Coupled Congestion Control
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+#include <net/tcp.h>
+#include <net/mptcp.h>
+
+#include <linux/module.h>
+
+/* Scaling is done in the numerator with alpha_scale_num and in the denominator
+ * with alpha_scale_den.
+ *
+ * To downscale, we just need to use alpha_scale.
+ *
+ * We have: alpha_scale = alpha_scale_num / (alpha_scale_den ^ 2)
+ */
+static int alpha_scale_den = 10;
+static int alpha_scale_num = 32;
+static int alpha_scale = 12;
+
+struct mptcp_ccc {
+       u64     alpha;
+       bool    forced_update;
+};
+
+static inline int mptcp_ccc_sk_can_send(const struct sock *sk)
+{
+       return mptcp_sk_can_send(sk) && tcp_sk(sk)->srtt;
+}
+
+static inline u64 mptcp_get_alpha(struct sock *meta_sk)
+{
+       struct mptcp_ccc *mptcp_ccc = inet_csk_ca(meta_sk);
+       return mptcp_ccc->alpha;
+}
+
+static inline void mptcp_set_alpha(struct sock *meta_sk, u64 alpha)
+{
+       struct mptcp_ccc *mptcp_ccc = inet_csk_ca(meta_sk);
+       mptcp_ccc->alpha = alpha;
+}
+
+static inline u64 mptcp_ccc_scale(u32 val, int scale)
+{
+       return (u64) val << scale;
+}
+
+static inline bool mptcp_get_forced(struct sock *meta_sk)
+{
+       struct mptcp_ccc *mptcp_ccc = inet_csk_ca(meta_sk);
+       return mptcp_ccc->forced_update;
+}
+
+static inline void mptcp_set_forced(struct sock *meta_sk, bool force)
+{
+       struct mptcp_ccc *mptcp_ccc = inet_csk_ca(meta_sk);
+       mptcp_ccc->forced_update = force;
+}
+
+static void mptcp_ccc_recalc_alpha(struct sock *sk)
+{
+       struct mptcp_cb *mpcb = tcp_sk(sk)->mpcb;
+       struct sock *sub_sk;
+       int best_cwnd = 0, best_rtt = 0, can_send = 0;
+       u64 max_numerator = 0, sum_denominator = 0, alpha = 1;
+
+       if (!mpcb)
+               return;
+
+       /* Only one subflow left - fall back to normal reno-behavior
+        * (set alpha to 1) */
+       if (mpcb->cnt_established <= 1)
+               goto exit;
+
+       /* Do regular alpha-calculation for multiple subflows */
+
+       /* Find the max numerator of the alpha-calculation */
+       mptcp_for_each_sk(mpcb, sub_sk) {
+               struct tcp_sock *sub_tp = tcp_sk(sub_sk);
+               u64 tmp;
+
+               if (!mptcp_ccc_sk_can_send(sub_sk))
+                       continue;
+
+               can_send++;
+
+               /* We need to look for the path, that provides the max-value.
+                * Integer-overflow is not possible here, because
+                * tmp will be in u64.
+                */
+               tmp = div64_u64(mptcp_ccc_scale(sub_tp->snd_cwnd,
+                               alpha_scale_num), (u64)sub_tp->srtt * sub_tp->srtt);
+
+               if (tmp >= max_numerator) {
+                       max_numerator = tmp;
+                       best_cwnd = sub_tp->snd_cwnd;
+                       best_rtt = sub_tp->srtt;
+               }
+       }
+
+       /* No subflow is able to send - we don't care anymore */
+       if (unlikely(!can_send))
+               goto exit;
+
+       /* Calculate the denominator */
+       mptcp_for_each_sk(mpcb, sub_sk) {
+               struct tcp_sock *sub_tp = tcp_sk(sub_sk);
+
+               if (!mptcp_ccc_sk_can_send(sub_sk))
+                       continue;
+
+               sum_denominator += div_u64(
+                               mptcp_ccc_scale(sub_tp->snd_cwnd,
+                                               alpha_scale_den) * best_rtt,
+                                               sub_tp->srtt);
+       }
+       sum_denominator *= sum_denominator;
+       if (unlikely(!sum_denominator)) {
+               pr_err("%s: sum_denominator == 0, cnt_established:%d\n",
+                      __func__, mpcb->cnt_established);
+               mptcp_for_each_sk(mpcb, sub_sk) {
+                       struct tcp_sock *sub_tp = tcp_sk(sub_sk);
+                       pr_err("%s: pi:%d, state:%d\n, rtt:%u, cwnd: %u",
+                              __func__, sub_tp->mptcp->path_index,
+                              sub_sk->sk_state, sub_tp->srtt,
+                              sub_tp->snd_cwnd);
+               }
+       }
+
+       alpha = div64_u64(mptcp_ccc_scale(best_cwnd, alpha_scale_num), sum_denominator);
+
+       if (unlikely(!alpha))
+               alpha = 1;
+
+exit:
+       mptcp_set_alpha(mptcp_meta_sk(sk), alpha);
+}
+
+static void mptcp_ccc_init(struct sock *sk)
+{
+       if (tcp_sk(sk)->mpc) {
+               mptcp_set_forced(mptcp_meta_sk(sk), 0);
+               mptcp_set_alpha(mptcp_meta_sk(sk), 1);
+       }
+       /* If we do not mptcp, behave like reno: return */
+}
+
+static void mptcp_ccc_cwnd_event(struct sock *sk, enum tcp_ca_event event)
+{
+       if (event == CA_EVENT_LOSS)
+               mptcp_ccc_recalc_alpha(sk);
+}
+
+static void mptcp_ccc_set_state(struct sock *sk, u8 ca_state)
+{
+       if (!tcp_sk(sk)->mpc)
+               return;
+
+       mptcp_set_forced(mptcp_meta_sk(sk), 1);
+}
+
+static void mptcp_ccc_cong_avoid(struct sock *sk, u32 ack, u32 acked, u32 in_flight)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct mptcp_cb *mpcb = tp->mpcb;
+       int snd_cwnd;
+
+       if (!tp->mpc) {
+               tcp_reno_cong_avoid(sk, ack, acked, in_flight);
+               return;
+       }
+
+       if (!tcp_is_cwnd_limited(sk, in_flight))
+               return;
+
+       if (tp->snd_cwnd <= tp->snd_ssthresh) {
+               /* In "safe" area, increase. */
+               tcp_slow_start(tp, acked);
+               mptcp_ccc_recalc_alpha(sk);
+               return;
+       }
+
+       if (mptcp_get_forced(mptcp_meta_sk(sk))) {
+               mptcp_ccc_recalc_alpha(sk);
+               mptcp_set_forced(mptcp_meta_sk(sk), 0);
+       }
+
+       if (mpcb->cnt_established > 1) {
+               u64 alpha = mptcp_get_alpha(mptcp_meta_sk(sk));
+
+               /* This may happen, if at the initialization, the mpcb
+                * was not yet attached to the sock, and thus
+                * initializing alpha failed.
+                */
+               if (unlikely(!alpha))
+                       alpha = 1;
+
+               snd_cwnd = (int) div_u64 ((u64) mptcp_ccc_scale(1, alpha_scale),
+                                               alpha);
+
+               /* snd_cwnd_cnt >= max (scale * tot_cwnd / alpha, cwnd)
+                * Thus, we select here the max value. */
+               if (snd_cwnd < tp->snd_cwnd)
+                       snd_cwnd = tp->snd_cwnd;
+       } else {
+               snd_cwnd = tp->snd_cwnd;
+       }
+
+       if (tp->snd_cwnd_cnt >= snd_cwnd) {
+               if (tp->snd_cwnd < tp->snd_cwnd_clamp) {
+                       tp->snd_cwnd++;
+                       mptcp_ccc_recalc_alpha(sk);
+               }
+
+               tp->snd_cwnd_cnt = 0;
+       } else {
+               tp->snd_cwnd_cnt++;
+       }
+}
+
+static struct tcp_congestion_ops mptcp_ccc = {
+       .init           = mptcp_ccc_init,
+       .ssthresh       = tcp_reno_ssthresh,
+       .cong_avoid     = mptcp_ccc_cong_avoid,
+       .cwnd_event     = mptcp_ccc_cwnd_event,
+       .set_state      = mptcp_ccc_set_state,
+       .min_cwnd       = tcp_reno_min_cwnd,
+       .owner          = THIS_MODULE,
+       .name           = "coupled",
+};
+
+static int __init mptcp_ccc_register(void)
+{
+       BUILD_BUG_ON(sizeof(struct mptcp_ccc) > ICSK_CA_PRIV_SIZE);
+       return tcp_register_congestion_control(&mptcp_ccc);
+}
+
+static void __exit mptcp_ccc_unregister(void)
+{
+       tcp_unregister_congestion_control(&mptcp_ccc);
+}
+
+module_init(mptcp_ccc_register);
+module_exit(mptcp_ccc_unregister);
+
+MODULE_AUTHOR("Christoph Paasch, Sébastien Barré");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MPTCP COUPLED CONGESTION CONTROL");
+MODULE_VERSION("0.1");
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_ctrl.c linux-3.14.45/net/mptcp/mptcp_ctrl.c
--- linux-3.14.45.orig/net/mptcp/mptcp_ctrl.c   1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_ctrl.c        2015-06-24 14:15:48.891862483 +0200
@@ -0,0 +1,2270 @@
+/*
+ *     MPTCP implementation - MPTCP-control
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <net/inet_common.h>
+#include <net/inet6_hashtables.h>
+#include <net/ipv6.h>
+#include <net/ip6_checksum.h>
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/mptcp_v6.h>
+#endif
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <net/tcp_states.h>
+#include <net/transp_v6.h>
+#include <net/xfrm.h>
+
+#include <linux/cryptohash.h>
+#include <linux/kconfig.h>
+#include <linux/module.h>
+#include <linux/netpoll.h>
+#include <linux/list.h>
+#include <linux/jhash.h>
+#include <linux/tcp.h>
+#include <linux/net.h>
+#include <linux/in.h>
+#include <linux/random.h>
+#include <linux/inetdevice.h>
+#include <linux/workqueue.h>
+#include <linux/atomic.h>
+#include <linux/sysctl.h>
+
+static struct kmem_cache *mptcp_sock_cache __read_mostly;
+static struct kmem_cache *mptcp_cb_cache __read_mostly;
+static struct kmem_cache *mptcp_tw_cache __read_mostly;
+
+int sysctl_mptcp_enabled __read_mostly = 1;
+int sysctl_mptcp_checksum __read_mostly = 1;
+int sysctl_mptcp_debug __read_mostly;
+EXPORT_SYMBOL(sysctl_mptcp_debug);
+int sysctl_mptcp_syn_retries __read_mostly = 3;
+
+bool mptcp_init_failed __read_mostly;
+
+static int proc_mptcp_path_manager(ctl_table *ctl, int write,
+                                  void __user *buffer, size_t *lenp,
+                                  loff_t *ppos)
+{
+       char val[MPTCP_PM_NAME_MAX];
+       ctl_table tbl = {
+               .data = val,
+               .maxlen = MPTCP_PM_NAME_MAX,
+       };
+       int ret;
+
+       mptcp_get_default_path_manager(val);
+
+       ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
+       if (write && ret == 0)
+               ret = mptcp_set_default_path_manager(val);
+       return ret;
+}
+
+static struct ctl_table mptcp_table[] = {
+       {
+               .procname = "mptcp_enabled",
+               .data = &sysctl_mptcp_enabled,
+               .maxlen = sizeof(int),
+               .mode = 0644,
+               .proc_handler = &proc_dointvec
+       },
+       {
+               .procname = "mptcp_checksum",
+               .data = &sysctl_mptcp_checksum,
+               .maxlen = sizeof(int),
+               .mode = 0644,
+               .proc_handler = &proc_dointvec
+       },
+       {
+               .procname = "mptcp_debug",
+               .data = &sysctl_mptcp_debug,
+               .maxlen = sizeof(int),
+               .mode = 0644,
+               .proc_handler = &proc_dointvec
+       },
+       {
+               .procname = "mptcp_syn_retries",
+               .data = &sysctl_mptcp_syn_retries,
+               .maxlen = sizeof(int),
+               .mode = 0644,
+               .proc_handler = &proc_dointvec
+       },
+       {
+               .procname       = "mptcp_path_manager",
+               .mode           = 0644,
+               .maxlen         = MPTCP_PM_NAME_MAX,
+               .proc_handler   = proc_mptcp_path_manager,
+       },
+       { }
+};
+
+static inline u32 mptcp_hash_tk(u32 token)
+{
+       return token % MPTCP_HASH_SIZE;
+}
+
+struct hlist_nulls_head tk_hashtable[MPTCP_HASH_SIZE];
+EXPORT_SYMBOL(tk_hashtable);
+
+/* This second hashtable is needed to retrieve request socks
+ * created as a result of a join request. While the SYN contains
+ * the token, the final ack does not, so we need a separate hashtable
+ * to retrieve the mpcb.
+ */
+struct list_head mptcp_reqsk_htb[MPTCP_HASH_SIZE];
+spinlock_t mptcp_reqsk_hlock;  /* hashtable protection */
+
+/* The following hash table is used to avoid collision of token */
+static struct hlist_nulls_head mptcp_reqsk_tk_htb[MPTCP_HASH_SIZE];
+spinlock_t mptcp_tk_hashlock;  /* hashtable protection */
+
+static int mptcp_reqsk_find_tk(u32 token)
+{
+       u32 hash = mptcp_hash_tk(token);
+       struct mptcp_request_sock *mtreqsk;
+       const struct hlist_nulls_node *node;
+
+       hlist_nulls_for_each_entry_rcu(mtreqsk, node,
+                                      &mptcp_reqsk_tk_htb[hash], collide_tk) {
+               if (token == mtreqsk->mptcp_loc_token)
+                       return 1;
+       }
+       return 0;
+}
+
+static void mptcp_reqsk_insert_tk(struct request_sock *reqsk, u32 token)
+{
+       u32 hash = mptcp_hash_tk(token);
+
+       hlist_nulls_add_head_rcu(&mptcp_rsk(reqsk)->collide_tk,
+                                &mptcp_reqsk_tk_htb[hash]);
+}
+
+static void mptcp_reqsk_remove_tk(struct request_sock *reqsk)
+{
+       rcu_read_lock();
+       spin_lock(&mptcp_tk_hashlock);
+       hlist_nulls_del_init_rcu(&mptcp_rsk(reqsk)->collide_tk);
+       spin_unlock(&mptcp_tk_hashlock);
+       rcu_read_unlock();
+}
+
+void mptcp_reqsk_destructor(struct request_sock *req)
+{
+       if (!mptcp_rsk(req)->mpcb) {
+               if (in_softirq()) {
+                       mptcp_reqsk_remove_tk(req);
+               } else {
+                       rcu_read_lock_bh();
+                       spin_lock(&mptcp_tk_hashlock);
+                       hlist_nulls_del_init_rcu(&mptcp_rsk(req)->collide_tk);
+                       spin_unlock(&mptcp_tk_hashlock);
+                       rcu_read_unlock_bh();
+               }
+       } else {
+               mptcp_hash_request_remove(req);
+       }
+}
+
+static void __mptcp_hash_insert(struct tcp_sock *meta_tp, u32 token)
+{
+       u32 hash = mptcp_hash_tk(token);
+       hlist_nulls_add_head_rcu(&meta_tp->tk_table, &tk_hashtable[hash]);
+       meta_tp->inside_tk_table = 1;
+}
+
+static int mptcp_find_token(u32 token)
+{
+       u32 hash = mptcp_hash_tk(token);
+       struct tcp_sock *meta_tp;
+       const struct hlist_nulls_node *node;
+
+       hlist_nulls_for_each_entry_rcu(meta_tp, node, &tk_hashtable[hash], tk_table) {
+               if (token == meta_tp->mptcp_loc_token)
+                       return 1;
+       }
+       return 0;
+}
+
+static void mptcp_set_key_reqsk(struct request_sock *req,
+                               const struct sk_buff *skb)
+{
+       struct inet_request_sock *ireq = inet_rsk(req);
+       struct mptcp_request_sock *mtreq = mptcp_rsk(req);
+
+       if (skb->protocol == htons(ETH_P_IP)) {
+               mtreq->mptcp_loc_key = mptcp_v4_get_key(ip_hdr(skb)->saddr,
+                                                       ip_hdr(skb)->daddr,
+                                                       htons(ireq->ir_num),
+                                                       ireq->ir_rmt_port);
+#if IS_ENABLED(CONFIG_IPV6)
+       } else {
+               mtreq->mptcp_loc_key = mptcp_v6_get_key(ipv6_hdr(skb)->saddr.s6_addr32,
+                                                       ipv6_hdr(skb)->daddr.s6_addr32,
+                                                       htons(ireq->ir_num),
+                                                       ireq->ir_rmt_port);
+#endif
+       }
+
+       mptcp_key_sha1(mtreq->mptcp_loc_key, &mtreq->mptcp_loc_token, NULL);
+}
+
+/* New MPTCP-connection request, prepare a new token for the meta-socket that
+ * will be created in mptcp_check_req_master(), and store the received token.
+ */
+void mptcp_reqsk_new_mptcp(struct request_sock *req,
+                          const struct tcp_options_received *rx_opt,
+                          const struct mptcp_options_received *mopt,
+                          const struct sk_buff *skb)
+{
+       struct mptcp_request_sock *mtreq = mptcp_rsk(req);
+
+       tcp_rsk(req)->saw_mpc = 1;
+
+       rcu_read_lock();
+       spin_lock(&mptcp_tk_hashlock);
+       do {
+               mptcp_set_key_reqsk(req, skb);
+       } while (mptcp_reqsk_find_tk(mtreq->mptcp_loc_token) ||
+                mptcp_find_token(mtreq->mptcp_loc_token));
+
+       mptcp_reqsk_insert_tk(req, mtreq->mptcp_loc_token);
+       spin_unlock(&mptcp_tk_hashlock);
+       rcu_read_unlock();
+       mtreq->mptcp_rem_key = mopt->mptcp_key;
+}
+
+static void mptcp_set_key_sk(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_sock *isk = inet_sk(sk);
+
+       if (sk->sk_family == AF_INET)
+               tp->mptcp_loc_key = mptcp_v4_get_key(isk->inet_saddr,
+                                                    isk->inet_daddr,
+                                                    isk->inet_sport,
+                                                    isk->inet_dport);
+#if IS_ENABLED(CONFIG_IPV6)
+       else
+               tp->mptcp_loc_key = mptcp_v6_get_key(inet6_sk(sk)->saddr.s6_addr32,
+                                                    sk->sk_v6_daddr.s6_addr32,
+                                                    isk->inet_sport,
+                                                    isk->inet_dport);
+#endif
+
+       mptcp_key_sha1(tp->mptcp_loc_key,
+                      &tp->mptcp_loc_token, NULL);
+}
+
+void mptcp_connect_init(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       rcu_read_lock_bh();
+       spin_lock(&mptcp_tk_hashlock);
+       do {
+               mptcp_set_key_sk(sk);
+       } while (mptcp_reqsk_find_tk(tp->mptcp_loc_token) ||
+                mptcp_find_token(tp->mptcp_loc_token));
+
+       __mptcp_hash_insert(tp, tp->mptcp_loc_token);
+       spin_unlock(&mptcp_tk_hashlock);
+       rcu_read_unlock_bh();
+}
+
+/**
+ * This function increments the refcount of the mpcb struct.
+ * It is the responsibility of the caller to decrement when releasing
+ * the structure.
+ */
+struct sock *mptcp_hash_find(struct net *net, u32 token)
+{
+       u32 hash = mptcp_hash_tk(token);
+       struct tcp_sock *meta_tp;
+       struct sock *meta_sk = NULL;
+       struct hlist_nulls_node *node;
+
+       rcu_read_lock();
+       hlist_nulls_for_each_entry_rcu(meta_tp, node, &tk_hashtable[hash],
+                                      tk_table) {
+               meta_sk = (struct sock *)meta_tp;
+               if (token == meta_tp->mptcp_loc_token &&
+                   net_eq(net, sock_net(meta_sk)) &&
+                   atomic_inc_not_zero(&meta_sk->sk_refcnt))
+                       break;
+               meta_sk = NULL;
+       }
+       rcu_read_unlock();
+       return meta_sk;
+}
+
+void mptcp_hash_remove_bh(struct tcp_sock *meta_tp)
+{
+       /* remove from the token hashtable */
+       rcu_read_lock_bh();
+       spin_lock(&mptcp_tk_hashlock);
+       hlist_nulls_del_init_rcu(&meta_tp->tk_table);
+       meta_tp->inside_tk_table = 0;
+       spin_unlock(&mptcp_tk_hashlock);
+       rcu_read_unlock_bh();
+}
+
+void mptcp_hash_remove(struct tcp_sock *meta_tp)
+{
+       rcu_read_lock();
+       spin_lock(&mptcp_tk_hashlock);
+       hlist_nulls_del_init_rcu(&meta_tp->tk_table);
+       meta_tp->inside_tk_table = 0;
+       spin_unlock(&mptcp_tk_hashlock);
+       rcu_read_unlock();
+}
+
+static struct sock *mptcp_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
+                                       struct request_sock *req,
+                                       struct dst_entry *dst)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+       if (sk->sk_family == AF_INET6)
+               return tcp_v6_syn_recv_sock(sk, skb, req, dst);
+
+       /* sk->sk_family == AF_INET */
+       if (req->rsk_ops->family == AF_INET6)
+               return mptcp_v6v4_syn_recv_sock(sk, skb, req, dst);
+#endif
+
+       /* sk->sk_family == AF_INET && req->rsk_ops->family == AF_INET */
+       return tcp_v4_syn_recv_sock(sk, skb, req, dst);
+}
+
+struct sock *mptcp_select_ack_sock(const struct sock *meta_sk, int copied)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sock *sk, *subsk = NULL;
+       u32 max_data_seq = 0;
+       /* max_data_seq initialized to correct compiler-warning.
+        * But the initialization is handled by max_data_seq_set
+        */
+       short max_data_seq_set = 0;
+       u32 min_time = 0xffffffff;
+
+       /* How do we select the subflow to send the window-update on?
+        *
+        * 1. He has to be in a state where he can send an ack and is
+        *           operational (pf = 0).
+        * 2. He has to be one of those subflow who recently
+        *    contributed to the received stream
+        *    (this guarantees a working subflow)
+        *    a) its latest data_seq received is after the original
+        *       copied_seq.
+        *       We select the one with the lowest rtt, so that the
+        *       window-update reaches our peer the fastest.
+        *    b) if no subflow has this kind of data_seq (e.g., very
+        *       strange meta-level retransmissions going on), we take
+        *       the subflow who last sent the highest data_seq.
+        */
+       mptcp_for_each_sk(meta_tp->mpcb, sk) {
+               struct tcp_sock *tp = tcp_sk(sk);
+
+               if (!mptcp_sk_can_send_ack(sk) || tp->pf)
+                       continue;
+
+               /* Select among those who contributed to the
+                * current receive-queue.
+                */
+               if (copied && after(tp->mptcp->last_data_seq, meta_tp->copied_seq - copied)) {
+                       if (tp->srtt < min_time) {
+                               min_time = tp->srtt;
+                               subsk = sk;
+                               max_data_seq_set = 0;
+                       }
+                       continue;
+               }
+
+               if (!subsk && !max_data_seq_set) {
+                       max_data_seq = tp->mptcp->last_data_seq;
+                       max_data_seq_set = 1;
+                       subsk = sk;
+               }
+
+               /* Otherwise, take the one with the highest data_seq */
+               if ((!subsk || max_data_seq_set) &&
+                   after(tp->mptcp->last_data_seq, max_data_seq)) {
+                       max_data_seq = tp->mptcp->last_data_seq;
+                       subsk = sk;
+               }
+       }
+
+       if (!subsk) {
+               mptcp_debug("%s subsk is null, copied %d, cseq %u\n", __func__,
+                           copied, meta_tp->copied_seq);
+               mptcp_for_each_sk(meta_tp->mpcb, sk) {
+                       struct tcp_sock *tp = tcp_sk(sk);
+                       mptcp_debug("%s pi %d state %u last_dseq %u\n",
+                                   __func__, tp->mptcp->path_index, sk->sk_state,
+                                   tp->mptcp->last_data_seq);
+               }
+       }
+
+       return subsk;
+}
+EXPORT_SYMBOL(mptcp_select_ack_sock);
+
+static void mptcp_sock_def_error_report(struct sock *sk)
+{
+       struct mptcp_cb *mpcb = tcp_sk(sk)->mpcb;
+
+       if (!sock_flag(sk, SOCK_DEAD))
+               mptcp_sub_close(sk, 0);
+
+       if (mpcb->infinite_mapping_rcv || mpcb->infinite_mapping_snd ||
+           mpcb->send_infinite_mapping) {
+               struct sock *meta_sk = mptcp_meta_sk(sk);
+
+               meta_sk->sk_err = sk->sk_err;
+               meta_sk->sk_err_soft = sk->sk_err_soft;
+
+               if (!sock_flag(meta_sk, SOCK_DEAD))
+                       meta_sk->sk_error_report(meta_sk);
+
+               tcp_done(meta_sk);
+       }
+
+       sk->sk_err = 0;
+       return;
+}
+
+static void mptcp_mpcb_put(struct mptcp_cb *mpcb)
+{
+       if (atomic_dec_and_test(&mpcb->mpcb_refcnt)) {
+               mptcp_cleanup_path_manager(mpcb);
+               kmem_cache_free(mptcp_cb_cache, mpcb);
+       }
+}
+
+static void mptcp_sock_destruct(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       inet_sock_destruct(sk);
+
+       BUG_ON(!list_empty(&tp->mptcp->cb_list));
+
+       kmem_cache_free(mptcp_sock_cache, tp->mptcp);
+       tp->mptcp = NULL;
+
+       if (!is_meta_sk(sk) && !tp->was_meta_sk) {
+               /* Taken when mpcb pointer was set */
+               sock_put(mptcp_meta_sk(sk));
+               mptcp_mpcb_put(tp->mpcb);
+       } else {
+               struct mptcp_cb *mpcb = tp->mpcb;
+               struct mptcp_tw *mptw;
+
+               /* The mpcb is disappearing - we can make the final
+                * update to the rcv_nxt of the time-wait-sock and remove
+                * its reference to the mpcb.
+                */
+               spin_lock_bh(&mpcb->tw_lock);
+               list_for_each_entry_rcu(mptw, &mpcb->tw_list, list) {
+                       list_del_rcu(&mptw->list);
+                       mptw->in_list = 0;
+                       mptcp_mpcb_put(mpcb);
+                       rcu_assign_pointer(mptw->mpcb, NULL);
+               }
+               spin_unlock_bh(&mpcb->tw_lock);
+
+               mptcp_mpcb_put(mpcb);
+
+               mptcp_debug("%s destroying meta-sk\n", __func__);
+       }
+}
+
+void mptcp_destroy_sock(struct sock *sk)
+{
+       if (is_meta_sk(sk)) {
+               struct sock *sk_it, *tmpsk;
+
+               __skb_queue_purge(&tcp_sk(sk)->mpcb->reinject_queue);
+               mptcp_purge_ofo_queue(tcp_sk(sk));
+
+               /* We have to close all remaining subflows. Normally, they
+                * should all be about to get closed. But, if the kernel is
+                * forcing a closure (e.g., tcp_write_err), the subflows might
+                * not have been closed properly (as we are waiting for the
+                * DATA_ACK of the DATA_FIN).
+                */
+               mptcp_for_each_sk_safe(tcp_sk(sk)->mpcb, sk_it, tmpsk) {
+                       /* Already did call tcp_close - waiting for graceful
+                        * closure, or if we are retransmitting fast-close on
+                        * the subflow. The reset (or timeout) will kill the
+                        * subflow..
+                        */
+                       if (tcp_sk(sk_it)->closing ||
+                           tcp_sk(sk_it)->send_mp_fclose)
+                               continue;
+
+                       /* Allow the delayed work first to prevent time-wait state */
+                       if (delayed_work_pending(&tcp_sk(sk_it)->mptcp->work))
+                               continue;
+
+                       mptcp_sub_close(sk_it, 0);
+               }
+       } else {
+               mptcp_del_sock(sk);
+       }
+}
+
+static void mptcp_set_state(struct sock *sk)
+{
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+
+       /* Meta is not yet established - wake up the application */
+       if ((1 << meta_sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV) &&
+           sk->sk_state == TCP_ESTABLISHED) {
+               tcp_set_state(meta_sk, TCP_ESTABLISHED);
+
+               if (!sock_flag(meta_sk, SOCK_DEAD)) {
+                       meta_sk->sk_state_change(meta_sk);
+                       sk_wake_async(meta_sk, SOCK_WAKE_IO, POLL_OUT);
+               }
+       }
+
+       if (sk->sk_state == TCP_ESTABLISHED) {
+               tcp_sk(sk)->mptcp->establish_increased = 1;
+               tcp_sk(sk)->mpcb->cnt_established++;
+       }
+}
+
+u32 mptcp_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
+u32 mptcp_key_seed = 0;
+
+void mptcp_key_sha1(u64 key, u32 *token, u64 *idsn)
+{
+       u32 workspace[SHA_WORKSPACE_WORDS];
+       u32 mptcp_hashed_key[SHA_DIGEST_WORDS];
+       u8 input[64];
+       int i;
+
+       memset(workspace, 0, sizeof(workspace));
+
+       /* Initialize input with appropriate padding */
+       memset(&input[9], 0, sizeof(input) - 10); /* -10, because the last byte
+                                                  * is explicitly set too */
+       memcpy(input, &key, sizeof(key)); /* Copy key to the msg beginning */
+       input[8] = 0x80; /* Padding: First bit after message = 1 */
+       input[63] = 0x40; /* Padding: Length of the message = 64 bits */
+
+       sha_init(mptcp_hashed_key);
+       sha_transform(mptcp_hashed_key, input, workspace);
+
+       for (i = 0; i < 5; i++)
+               mptcp_hashed_key[i] = cpu_to_be32(mptcp_hashed_key[i]);
+
+       if (token)
+               *token = mptcp_hashed_key[0];
+       if (idsn)
+               *idsn = *((u64 *)&mptcp_hashed_key[3]);
+}
+
+void mptcp_hmac_sha1(u8 *key_1, u8 *key_2, u8 *rand_1, u8 *rand_2,
+                      u32 *hash_out)
+{
+       u32 workspace[SHA_WORKSPACE_WORDS];
+       u8 input[128]; /* 2 512-bit blocks */
+       int i;
+
+       memset(workspace, 0, sizeof(workspace));
+
+       /* Generate key xored with ipad */
+       memset(input, 0x36, 64);
+       for (i = 0; i < 8; i++)
+               input[i] ^= key_1[i];
+       for (i = 0; i < 8; i++)
+               input[i + 8] ^= key_2[i];
+
+       memcpy(&input[64], rand_1, 4);
+       memcpy(&input[68], rand_2, 4);
+       input[72] = 0x80; /* Padding: First bit after message = 1 */
+       memset(&input[73], 0, 53);
+
+       /* Padding: Length of the message = 512 + 64 bits */
+       input[126] = 0x02;
+       input[127] = 0x40;
+
+       sha_init(hash_out);
+       sha_transform(hash_out, input, workspace);
+       memset(workspace, 0, sizeof(workspace));
+
+       sha_transform(hash_out, &input[64], workspace);
+       memset(workspace, 0, sizeof(workspace));
+
+       for (i = 0; i < 5; i++)
+               hash_out[i] = cpu_to_be32(hash_out[i]);
+
+       /* Prepare second part of hmac */
+       memset(input, 0x5C, 64);
+       for (i = 0; i < 8; i++)
+               input[i] ^= key_1[i];
+       for (i = 0; i < 8; i++)
+               input[i + 8] ^= key_2[i];
+
+       memcpy(&input[64], hash_out, 20);
+       input[84] = 0x80;
+       memset(&input[85], 0, 41);
+
+       /* Padding: Length of the message = 512 + 160 bits */
+       input[126] = 0x02;
+       input[127] = 0xA0;
+
+       sha_init(hash_out);
+       sha_transform(hash_out, input, workspace);
+       memset(workspace, 0, sizeof(workspace));
+
+       sha_transform(hash_out, &input[64], workspace);
+
+       for (i = 0; i < 5; i++)
+               hash_out[i] = cpu_to_be32(hash_out[i]);
+}
+
+static void mptcp_mpcb_inherit_sockopts(struct sock *meta_sk, struct sock *master_sk)
+{
+       /* Socket-options handled by mptcp_inherit_sk while creating the meta-sk.
+        * ======
+        * SO_SNDBUF, SO_SNDBUFFORCE, SO_RCVBUF, SO_RCVBUFFORCE, SO_RCVLOWAT,
+        * SO_RCVTIMEO, SO_SNDTIMEO, SO_ATTACH_FILTER, SO_DETACH_FILTER,
+        * TCP_NODELAY, TCP_CORK
+        *
+        * Socket-options handled in this function here
+        * ======
+        * TCP_DEFER_ACCEPT
+        *
+        * Socket-options on the todo-list
+        * ======
+        * SO_BINDTODEVICE - should probably prevent creation of new subsocks
+        *                   across other devices. - what about the api-draft?
+        * SO_DEBUG
+        * SO_REUSEADDR - probably we don't care about this
+        * SO_DONTROUTE, SO_BROADCAST
+        * SO_OOBINLINE
+        * SO_LINGER
+        * SO_TIMESTAMP* - I don't think this is of concern for a SOCK_STREAM
+        * SO_PASSSEC - I don't think this is of concern for a SOCK_STREAM
+        * SO_RXQ_OVFL
+        * TCP_COOKIE_TRANSACTIONS
+        * TCP_MAXSEG
+        * TCP_THIN_* - Handled by mptcp_inherit_sk, but we need to support this
+        *              in mptcp_retransmit_timer. AND we need to check what is
+        *              about the subsockets.
+        * TCP_LINGER2
+        * TCP_WINDOW_CLAMP
+        * TCP_USER_TIMEOUT
+        * TCP_MD5SIG
+        *
+        * Socket-options of no concern for the meta-socket (but for the subsocket)
+        * ======
+        * SO_PRIORITY
+        * SO_MARK
+        * TCP_CONGESTION
+        * TCP_SYNCNT
+        * TCP_QUICKACK
+        * SO_KEEPALIVE
+        */
+
+       /****** DEFER_ACCEPT-handler ******/
+
+       /* DEFER_ACCEPT is not of concern for new subflows - we always accept
+        * them
+        */
+       inet_csk(meta_sk)->icsk_accept_queue.rskq_defer_accept = 0;
+}
+
+static void mptcp_sub_inherit_sockopts(struct sock *meta_sk, struct sock *sub_sk)
+{
+       /* IP_TOS also goes to the subflow. */
+       if (inet_sk(sub_sk)->tos != inet_sk(meta_sk)->tos) {
+               inet_sk(sub_sk)->tos = inet_sk(meta_sk)->tos;
+               sub_sk->sk_priority = meta_sk->sk_priority;
+               sk_dst_reset(sub_sk);
+       }
+
+       /* Inherit SO_REUSEADDR */
+       sub_sk->sk_reuse = meta_sk->sk_reuse;
+
+       /* Inherit snd/rcv-buffer locks */
+       sub_sk->sk_userlocks = meta_sk->sk_userlocks & ~SOCK_BINDPORT_LOCK;
+}
+
+int mptcp_backlog_rcv(struct sock *meta_sk, struct sk_buff *skb)
+{
+       /* skb-sk may be NULL if we receive a packet immediatly after the
+        * SYN/ACK + MP_CAPABLE.
+        */
+       struct sock *sk = skb->sk ? skb->sk : meta_sk;
+       int ret = 0;
+
+       skb->sk = NULL;
+
+       if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
+               kfree_skb(skb);
+               return 0;
+       }
+
+       if (sk->sk_family == AF_INET)
+               ret = tcp_v4_do_rcv(sk, skb);
+#if IS_ENABLED(CONFIG_IPV6)
+       else
+               ret = tcp_v6_do_rcv(sk, skb);
+#endif
+
+       sock_put(sk);
+       return ret;
+}
+
+struct lock_class_key meta_key;
+struct lock_class_key meta_slock_key;
+
+/* Code heavily inspired from sk_clone() */
+static int mptcp_inherit_sk(const struct sock *sk, struct sock *newsk,
+                           int family, const gfp_t flags)
+{
+       struct sk_filter *filter;
+       struct proto *prot = newsk->sk_prot;
+       const struct inet_connection_sock_af_ops *af_ops = inet_csk(newsk)->icsk_af_ops;
+#ifdef CONFIG_SECURITY_NETWORK
+       void *sptr = newsk->sk_security;
+#endif
+
+       if (sk->sk_family == AF_INET) {
+               memcpy(newsk, sk, offsetof(struct sock, sk_dontcopy_begin));
+               memcpy(&newsk->sk_dontcopy_end, &sk->sk_dontcopy_end,
+                      sizeof(struct tcp_sock) - offsetof(struct sock, sk_dontcopy_end));
+       } else {
+               memcpy(newsk, sk, offsetof(struct sock, sk_dontcopy_begin));
+               memcpy(&newsk->sk_dontcopy_end, &sk->sk_dontcopy_end,
+                      sizeof(struct tcp6_sock) - offsetof(struct sock, sk_dontcopy_end));
+       }
+
+#ifdef CONFIG_SECURITY_NETWORK
+       newsk->sk_security = sptr;
+       security_sk_clone(sk, newsk);
+#endif
+
+       /* Has been changed by sock_copy above - we may need an IPv6-socket */
+       newsk->sk_family = family;
+       newsk->sk_prot = prot;
+       newsk->sk_prot_creator = prot;
+       inet_csk(newsk)->icsk_af_ops = af_ops;
+
+       /* We don't yet have the mptcp-point. Thus we still need inet_sock_destruct */
+       newsk->sk_destruct = inet_sock_destruct;
+
+       /* SANITY */
+       get_net(sock_net(newsk));
+       sk_node_init(&newsk->sk_node);
+       sock_lock_init_class_and_name(newsk, "slock-AF_INET-MPTCP",
+                                     &meta_slock_key, "sk_lock-AF_INET-MPTCP",
+                                     &meta_key);
+
+       /* Unlocks are in:
+        *
+        * 1. If we are creating the master-sk
+        *      * on client-side in tcp_rcv_state_process, "case TCP_SYN_SENT"
+        *      * on server-side in tcp_child_process
+        * 2. If we are creating another subsock
+        *      * Also in tcp_child_process
+        */
+       bh_lock_sock(newsk);
+       newsk->sk_backlog.head = NULL;
+       newsk->sk_backlog.tail = NULL;
+       newsk->sk_backlog.len = 0;
+
+       atomic_set(&newsk->sk_rmem_alloc, 0);
+       atomic_set(&newsk->sk_wmem_alloc, 1);
+       atomic_set(&newsk->sk_omem_alloc, 0);
+
+       skb_queue_head_init(&newsk->sk_receive_queue);
+       skb_queue_head_init(&newsk->sk_write_queue);
+#ifdef CONFIG_NET_DMA
+       skb_queue_head_init(&newsk->sk_async_wait_queue);
+#endif
+
+       spin_lock_init(&newsk->sk_dst_lock);
+       rwlock_init(&newsk->sk_callback_lock);
+       lockdep_set_class_and_name(&newsk->sk_callback_lock,
+                                  af_callback_keys + newsk->sk_family,
+                                  af_family_clock_key_strings[newsk->sk_family]);
+       newsk->sk_dst_cache     = NULL;
+       newsk->sk_rx_dst        = NULL;
+       newsk->sk_wmem_queued   = 0;
+       newsk->sk_forward_alloc = 0;
+       newsk->sk_send_head     = NULL;
+       newsk->sk_userlocks     = sk->sk_userlocks & ~SOCK_BINDPORT_LOCK;
+
+       tcp_sk(newsk)->mptcp = NULL;
+
+       sock_reset_flag(newsk, SOCK_DONE);
+       skb_queue_head_init(&newsk->sk_error_queue);
+
+       filter = rcu_dereference_protected(newsk->sk_filter, 1);
+       if (filter != NULL)
+               sk_filter_charge(newsk, filter);
+
+       if (unlikely(xfrm_sk_clone_policy(newsk))) {
+               /* It is still raw copy of parent, so invalidate
+                * destructor and make plain sk_free()
+                */
+               newsk->sk_destruct = NULL;
+               bh_unlock_sock(newsk);
+               sk_free(newsk);
+               newsk = NULL;
+               return -ENOMEM;
+       }
+
+       newsk->sk_err      = 0;
+       newsk->sk_priority = 0;
+       /* Before updating sk_refcnt, we must commit prior changes to memory
+        * (Documentation/RCU/rculist_nulls.txt for details)
+        */
+       smp_wmb();
+       atomic_set(&newsk->sk_refcnt, 2);
+
+       /* Increment the counter in the same struct proto as the master
+        * sock (sk_refcnt_debug_inc uses newsk->sk_prot->socks, that
+        * is the same as sk->sk_prot->socks, as this field was copied
+        * with memcpy).
+        *
+        * This _changes_ the previous behaviour, where
+        * tcp_create_openreq_child always was incrementing the
+        * equivalent to tcp_prot->socks (inet_sock_nr), so this have
+        * to be taken into account in all callers. -acme
+        */
+       sk_refcnt_debug_inc(newsk);
+       sk_set_socket(newsk, NULL);
+       newsk->sk_wq = NULL;
+
+       if (newsk->sk_prot->sockets_allocated)
+               percpu_counter_inc(newsk->sk_prot->sockets_allocated);
+
+       if (sock_flag(newsk, SOCK_TIMESTAMP) ||
+           sock_flag(newsk, SOCK_TIMESTAMPING_RX_SOFTWARE))
+               net_enable_timestamp();
+
+       return 0;
+}
+
+int mptcp_alloc_mpcb(struct sock *meta_sk, __u64 remote_key, u32 window)
+{
+       struct mptcp_cb *mpcb;
+       struct sock *master_sk;
+       struct inet_connection_sock *master_icsk, *meta_icsk = inet_csk(meta_sk);
+       struct tcp_sock *master_tp, *meta_tp = tcp_sk(meta_sk);
+       struct sk_buff *skb, *tmp;
+       u64 idsn;
+
+       master_sk = sk_prot_alloc(meta_sk->sk_prot, GFP_ATOMIC | __GFP_ZERO,
+                                 meta_sk->sk_family);
+       if (!master_sk)
+               return -ENOBUFS;
+
+       master_tp = tcp_sk(master_sk);
+       master_icsk = inet_csk(master_sk);
+
+       /* Need to set this here - it is needed by mptcp_inherit_sk */
+       master_sk->sk_prot = meta_sk->sk_prot;
+       master_sk->sk_prot_creator = meta_sk->sk_prot;
+       master_icsk->icsk_af_ops = meta_icsk->icsk_af_ops;
+
+       mpcb = kmem_cache_zalloc(mptcp_cb_cache, GFP_ATOMIC);
+       if (!mpcb) {
+               sk_free(master_sk);
+               return -ENOBUFS;
+       }
+
+       /* master_sk inherits from meta_sk */
+       if (mptcp_inherit_sk(meta_sk, master_sk, meta_sk->sk_family, GFP_ATOMIC)) {
+               kmem_cache_free(mptcp_cb_cache, mpcb);
+               return -ENOBUFS;
+       }
+
+#if IS_ENABLED(CONFIG_IPV6)
+       if (meta_icsk->icsk_af_ops == &ipv6_mapped) {
+               struct ipv6_pinfo *newnp, *np = inet6_sk(meta_sk);
+
+               inet_sk(master_sk)->pinet6 = &((struct tcp6_sock *)master_sk)->inet6;
+
+               newnp = inet6_sk(master_sk);
+               memcpy(newnp, np, sizeof(struct ipv6_pinfo));
+
+               newnp->ipv6_mc_list = NULL;
+               newnp->ipv6_ac_list = NULL;
+               newnp->ipv6_fl_list = NULL;
+               newnp->opt = NULL;
+               newnp->pktoptions = NULL;
+               (void)xchg(&newnp->rxpmtu, NULL);
+       } else if (meta_sk->sk_family == AF_INET6) {
+               struct ipv6_pinfo *newnp, *np = inet6_sk(meta_sk);
+
+               inet_sk(master_sk)->pinet6 = &((struct tcp6_sock *)master_sk)->inet6;
+
+               newnp = inet6_sk(master_sk);
+               memcpy(newnp, np, sizeof(struct ipv6_pinfo));
+
+               newnp->hop_limit        = -1;
+               newnp->mcast_hops       = IPV6_DEFAULT_MCASTHOPS;
+               newnp->mc_loop  = 1;
+               newnp->pmtudisc = IPV6_PMTUDISC_WANT;
+               newnp->ipv6only = sock_net(master_sk)->ipv6.sysctl.bindv6only;
+       }
+#endif
+
+       meta_tp->mptcp = kmem_cache_zalloc(mptcp_sock_cache, GFP_ATOMIC);
+       if (!meta_tp->mptcp) {
+               kmem_cache_free(mptcp_cb_cache, mpcb);
+               sk_free(master_sk);
+               return -ENOBUFS;
+       }
+
+       INIT_LIST_HEAD(&meta_tp->mptcp->cb_list);
+
+       /* Store the keys and generate the peer's token */
+       mpcb->mptcp_loc_key = meta_tp->mptcp_loc_key;
+       mpcb->mptcp_loc_token = meta_tp->mptcp_loc_token;
+
+       /* Generate Initial data-sequence-numbers */
+       mptcp_key_sha1(mpcb->mptcp_loc_key, NULL, &idsn);
+       idsn = ntohll(idsn) + 1;
+       mpcb->snd_high_order[0] = idsn >> 32;
+       mpcb->snd_high_order[1] = mpcb->snd_high_order[0] - 1;
+
+       meta_tp->write_seq = (u32)idsn;
+       meta_tp->snd_sml = meta_tp->write_seq;
+       meta_tp->snd_una = meta_tp->write_seq;
+       meta_tp->snd_nxt = meta_tp->write_seq;
+       meta_tp->pushed_seq = meta_tp->write_seq;
+       meta_tp->snd_up = meta_tp->write_seq;
+
+       mpcb->mptcp_rem_key = remote_key;
+       mptcp_key_sha1(mpcb->mptcp_rem_key, &mpcb->mptcp_rem_token, &idsn);
+       idsn = ntohll(idsn) + 1;
+       mpcb->rcv_high_order[0] = idsn >> 32;
+       mpcb->rcv_high_order[1] = mpcb->rcv_high_order[0] + 1;
+       meta_tp->copied_seq = (u32) idsn;
+       meta_tp->rcv_nxt = (u32) idsn;
+       meta_tp->rcv_wup = (u32) idsn;
+
+       meta_tp->snd_wl1 = meta_tp->rcv_nxt - 1;
+       meta_tp->snd_wnd = window;
+       meta_tp->retrans_stamp = 0; /* Set in tcp_connect() */
+
+       meta_tp->packets_out = 0;
+       meta_tp->mptcp->snt_isn = meta_tp->write_seq; /* Initial data-sequence-number */
+       meta_icsk->icsk_probes_out = 0;
+
+       /* Set mptcp-pointers */
+       master_tp->mpcb = mpcb;
+       master_tp->meta_sk = meta_sk;
+       meta_tp->mpcb = mpcb;
+       meta_tp->meta_sk = meta_sk;
+       mpcb->meta_sk = meta_sk;
+       mpcb->master_sk = master_sk;
+
+       set_mpc(meta_tp);
+       meta_tp->mptcp->attached = 0;
+       meta_tp->was_meta_sk = 0;
+
+       /* Initialize the queues */
+       skb_queue_head_init(&mpcb->reinject_queue);
+       skb_queue_head_init(&master_tp->out_of_order_queue);
+       tcp_prequeue_init(master_tp);
+       INIT_LIST_HEAD(&master_tp->tsq_node);
+
+       master_tp->tsq_flags = 0;
+
+       /* Copy the write-queue from the meta down to the master.
+        * This is necessary to get the SYN to the master-write-queue.
+        * No other data can be queued, before tcp_sendmsg waits for the
+        * connection to finish.
+        */
+       skb_queue_walk_safe(&meta_sk->sk_write_queue, skb, tmp) {
+               skb_unlink(skb, &meta_sk->sk_write_queue);
+               skb_queue_tail(&master_sk->sk_write_queue, skb);
+
+               master_sk->sk_wmem_queued += skb->truesize;
+               sk_mem_charge(master_sk, skb->truesize);
+       }
+
+       meta_sk->sk_wmem_queued = 0;
+       meta_sk->sk_forward_alloc = 0;
+
+       mutex_init(&mpcb->mpcb_mutex);
+
+       /* Init the accept_queue structure, we support a queue of 32 pending
+        * connections, it does not need to be huge, since we only store  here
+        * pending subflow creations.
+        */
+       if (reqsk_queue_alloc(&meta_icsk->icsk_accept_queue, 32, GFP_ATOMIC)) {
+               inet_put_port(master_sk);
+               kmem_cache_free(mptcp_sock_cache, meta_tp->mptcp);
+               kmem_cache_free(mptcp_cb_cache, mpcb);
+               sk_free(master_sk);
+               reset_mpc(meta_tp);
+               return -ENOMEM;
+       }
+
+       /* Redefine function-pointers as the meta-sk is now fully ready */
+       meta_sk->sk_backlog_rcv = mptcp_backlog_rcv;
+       meta_sk->sk_destruct = mptcp_sock_destruct;
+       mpcb->syn_recv_sock = mptcp_syn_recv_sock;
+
+       /* Meta-level retransmit timer */
+       meta_icsk->icsk_rto *= 2; /* Double of initial - rto */
+
+       tcp_init_xmit_timers(master_sk);
+       /* Has been set for sending out the SYN */
+       inet_csk_clear_xmit_timer(meta_sk, ICSK_TIME_RETRANS);
+
+       if (!meta_tp->inside_tk_table) {
+               /* Adding the meta_tp in the token hashtable - coming from server-side */
+               rcu_read_lock();
+               spin_lock(&mptcp_tk_hashlock);
+
+               __mptcp_hash_insert(meta_tp, mpcb->mptcp_loc_token);
+
+               spin_unlock(&mptcp_tk_hashlock);
+               rcu_read_unlock();
+       }
+       master_tp->inside_tk_table = 0;
+
+       /* Init time-wait stuff */
+       INIT_LIST_HEAD(&mpcb->tw_list);
+       spin_lock_init(&mpcb->tw_lock);
+
+       INIT_LIST_HEAD(&mpcb->callback_list);
+
+       mptcp_mpcb_inherit_sockopts(meta_sk, master_sk);
+
+       mpcb->orig_sk_rcvbuf = meta_sk->sk_rcvbuf;
+       mpcb->orig_sk_sndbuf = meta_sk->sk_sndbuf;
+       mpcb->orig_window_clamp = meta_tp->window_clamp;
+
+       /* The meta is directly linked - set refcnt to 1 */
+       atomic_set(&mpcb->mpcb_refcnt, 1);
+
+       mptcp_init_path_manager(mpcb);
+
+       mptcp_debug("%s: created mpcb with token %#x\n",
+                   __func__, mpcb->mptcp_loc_token);
+
+       return 0;
+}
+
+struct sock *mptcp_sk_clone(const struct sock *sk, int family,
+                           const gfp_t priority)
+{
+       struct sock *newsk = NULL;
+
+       if (family == AF_INET && sk->sk_family == AF_INET) {
+               newsk = sk_prot_alloc(&tcp_prot, priority, family);
+               if (!newsk)
+                       return NULL;
+
+               /* Set these pointers - they are needed by mptcp_inherit_sk */
+               newsk->sk_prot = &tcp_prot;
+               newsk->sk_prot_creator = &tcp_prot;
+               inet_csk(newsk)->icsk_af_ops = &ipv4_specific;
+               newsk->sk_family = AF_INET;
+       }
+#if IS_ENABLED(CONFIG_IPV6)
+       else {
+               newsk = sk_prot_alloc(&tcpv6_prot, priority, family);
+               if (!newsk)
+                       return NULL;
+
+               newsk->sk_prot = &tcpv6_prot;
+               newsk->sk_prot_creator = &tcpv6_prot;
+               if (family == AF_INET)
+                       inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
+               else
+                       inet_csk(newsk)->icsk_af_ops = &ipv6_specific;
+               newsk->sk_family = AF_INET6;
+       }
+#endif
+
+       if (mptcp_inherit_sk(sk, newsk, family, priority))
+               return NULL;
+
+       return newsk;
+}
+
+void mptcp_fallback_meta_sk(struct sock *meta_sk)
+{
+       kfree(inet_csk(meta_sk)->icsk_accept_queue.listen_opt);
+       kmem_cache_free(mptcp_sock_cache, tcp_sk(meta_sk)->mptcp);
+       kmem_cache_free(mptcp_cb_cache, tcp_sk(meta_sk)->mpcb);
+}
+
+int mptcp_add_sock(struct sock *meta_sk, struct sock *sk, u8 loc_id, u8 rem_id,
+                  gfp_t flags)
+{
+       struct mptcp_cb *mpcb   = tcp_sk(meta_sk)->mpcb;
+       struct tcp_sock *tp     = tcp_sk(sk);
+
+       tp->mptcp = kmem_cache_zalloc(mptcp_sock_cache, flags);
+       if (!tp->mptcp)
+               return -ENOMEM;
+
+       tp->mptcp->path_index = mptcp_set_new_pathindex(mpcb);
+       /* No more space for more subflows? */
+       if (!tp->mptcp->path_index) {
+               kmem_cache_free(mptcp_sock_cache, tp->mptcp);
+               return -EPERM;
+       }
+
+       INIT_LIST_HEAD(&tp->mptcp->cb_list);
+
+       tp->mptcp->tp = tp;
+       tp->mpcb = mpcb;
+       tp->meta_sk = meta_sk;
+       set_mpc(tp);
+       tp->mptcp->loc_id = loc_id;
+       tp->mptcp->rem_id = rem_id;
+       tp->mptcp->last_rbuf_opti = tcp_time_stamp;
+
+       /* The corresponding sock_put is in mptcp_sock_destruct(). It cannot be
+        * included in mptcp_del_sock(), because the mpcb must remain alive
+        * until the last subsocket is completely destroyed.
+        */
+       sock_hold(meta_sk);
+       atomic_inc(&mpcb->mpcb_refcnt);
+
+       tp->mptcp->next = mpcb->connection_list;
+       mpcb->connection_list = tp;
+       tp->mptcp->attached = 1;
+
+       mpcb->cnt_subflows++;
+       atomic_add(atomic_read(&((struct sock *)tp)->sk_rmem_alloc),
+                  &meta_sk->sk_rmem_alloc);
+
+       mptcp_sub_inherit_sockopts(meta_sk, sk);
+       INIT_DELAYED_WORK(&tp->mptcp->work, mptcp_sub_close_wq);
+
+       /* As we successfully allocated the mptcp_tcp_sock, we have to
+        * change the function-pointers here (for sk_destruct to work correctly)
+        */
+       sk->sk_error_report = mptcp_sock_def_error_report;
+       sk->sk_data_ready = mptcp_data_ready;
+       sk->sk_write_space = mptcp_write_space;
+       sk->sk_state_change = mptcp_set_state;
+       sk->sk_destruct = mptcp_sock_destruct;
+
+       if (sk->sk_family == AF_INET)
+               mptcp_debug("%s: token %#x pi %d, src_addr:%pI4:%d dst_addr:%pI4:%d, cnt_subflows now %d\n",
+                           __func__ , mpcb->mptcp_loc_token,
+                           tp->mptcp->path_index,
+                           &((struct inet_sock *)tp)->inet_saddr,
+                           ntohs(((struct inet_sock *)tp)->inet_sport),
+                           &((struct inet_sock *)tp)->inet_daddr,
+                           ntohs(((struct inet_sock *)tp)->inet_dport),
+                           mpcb->cnt_subflows);
+#if IS_ENABLED(CONFIG_IPV6)
+       else
+               mptcp_debug("%s: token %#x pi %d, src_addr:%pI6:%d dst_addr:%pI6:%d, cnt_subflows now %d\n",
+                           __func__ , mpcb->mptcp_loc_token,
+                           tp->mptcp->path_index, &inet6_sk(sk)->saddr,
+                           ntohs(((struct inet_sock *)tp)->inet_sport),
+                           &sk->sk_v6_daddr,
+                           ntohs(((struct inet_sock *)tp)->inet_dport),
+                           mpcb->cnt_subflows);
+#endif
+
+       return 0;
+}
+
+void mptcp_del_sock(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk), *tp_prev;
+       struct mptcp_cb *mpcb;
+
+       if (!tp->mptcp || !tp->mptcp->attached)
+               return;
+
+       mpcb = tp->mpcb;
+       tp_prev = mpcb->connection_list;
+
+       mptcp_debug("%s: Removing subsock tok %#x pi:%d state %d is_meta? %d\n",
+                   __func__, mpcb->mptcp_loc_token, tp->mptcp->path_index,
+                   sk->sk_state, is_meta_sk(sk));
+
+       if (tp_prev == tp) {
+               mpcb->connection_list = tp->mptcp->next;
+       } else {
+               for (; tp_prev && tp_prev->mptcp->next; tp_prev = tp_prev->mptcp->next) {
+                       if (tp_prev->mptcp->next == tp) {
+                               tp_prev->mptcp->next = tp->mptcp->next;
+                               break;
+                       }
+               }
+       }
+       mpcb->cnt_subflows--;
+       if (tp->mptcp->establish_increased)
+               mpcb->cnt_established--;
+
+       tp->mptcp->next = NULL;
+       tp->mptcp->attached = 0;
+       mpcb->path_index_bits &= ~(1 << tp->mptcp->path_index);
+
+       if (!skb_queue_empty(&sk->sk_write_queue))
+               mptcp_reinject_data(sk, 0);
+
+       if (is_master_tp(tp))
+               mpcb->master_sk = NULL;
+       else if (tp->mptcp->pre_established)
+               sk_stop_timer(sk, &tp->mptcp->mptcp_ack_timer);
+
+       rcu_assign_pointer(inet_sk(sk)->inet_opt, NULL);
+}
+
+/* Updates the metasocket ULID/port data, based on the given sock.
+ * The argument sock must be the sock accessible to the application.
+ * In this function, we update the meta socket info, based on the changes
+ * in the application socket (bind, address allocation, ...)
+ */
+void mptcp_update_metasocket(struct sock *sk, struct sock *meta_sk)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       union inet_addr addr;
+       int index;
+
+       /* Get the index of the local address */
+       if (sk->sk_family == AF_INET || mptcp_v6_is_v4_mapped(sk)) {
+               addr.ip = inet_sk(sk)->inet_saddr;
+               index = mpcb->pm_ops->get_local_index(AF_INET, &addr, sock_net(meta_sk));
+       } else {
+               addr.in6 = inet6_sk(sk)->saddr;
+               index = mpcb->pm_ops->get_local_index(AF_INET6, &addr, sock_net(meta_sk));
+       }
+
+       if (sk->sk_family == AF_INET || mptcp_v6_is_v4_mapped(sk)) {
+               mptcp_v4_add_raddress(mpcb,
+                                     (struct in_addr *)&inet_sk(sk)->inet_daddr,
+                                     0, 0);
+               if (index >= 0)
+                       mptcp_v4_set_init_addr_bit(mpcb, inet_sk(sk)->inet_daddr, index);
+       } else {
+#if IS_ENABLED(CONFIG_IPV6)
+               mptcp_v6_add_raddress(mpcb, &sk->sk_v6_daddr, 0, 0);
+               if (index >= 0)
+                       mptcp_v6_set_init_addr_bit(mpcb, &sk->sk_v6_daddr, index);
+#endif
+       }
+
+       if (mpcb->pm_ops->new_session)
+               mpcb->pm_ops->new_session(meta_sk, index);
+
+       tcp_sk(sk)->mptcp->send_mp_prio = tcp_sk(sk)->mptcp->low_prio;
+}
+
+/* Clean up the receive buffer for full frames taken by the user,
+ * then send an ACK if necessary.  COPIED is the number of bytes
+ * tcp_recvmsg has given to the user so far, it speeds up the
+ * calculation of whether or not we must ACK for the sake of
+ * a window update.
+ */
+void mptcp_cleanup_rbuf(struct sock *meta_sk, int copied)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sock *sk;
+       __u32 rcv_window_now = 0;
+
+       if (copied > 0 && !(meta_sk->sk_shutdown & RCV_SHUTDOWN)) {
+               rcv_window_now = tcp_receive_window(meta_tp);
+
+               if (2 * rcv_window_now > meta_tp->window_clamp)
+                       rcv_window_now = 0;
+       }
+
+       mptcp_for_each_sk(meta_tp->mpcb, sk) {
+               struct tcp_sock *tp = tcp_sk(sk);
+               const struct inet_connection_sock *icsk = inet_csk(sk);
+
+               if (!mptcp_sk_can_send_ack(sk))
+                       continue;
+
+               if (!inet_csk_ack_scheduled(sk))
+                       goto second_part;
+               /* Delayed ACKs frequently hit locked sockets during bulk
+                * receive.
+                */
+               if (icsk->icsk_ack.blocked ||
+                   /* Once-per-two-segments ACK was not sent by tcp_input.c */
+                   tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
+                   /* If this read emptied read buffer, we send ACK, if
+                    * connection is not bidirectional, user drained
+                    * receive buffer and there was a small segment
+                    * in queue.
+                    */
+                   (copied > 0 &&
+                    ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
+                     ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
+                      !icsk->icsk_ack.pingpong)) &&
+                    !atomic_read(&meta_sk->sk_rmem_alloc))) {
+                       tcp_send_ack(sk);
+                       continue;
+               }
+
+second_part:
+               /* This here is the second part of tcp_cleanup_rbuf */
+               if (rcv_window_now) {
+                       __u32 new_window = tp->__select_window(sk);
+
+                       /* Send ACK now, if this read freed lots of space
+                        * in our buffer. Certainly, new_window is new window.
+                        * We can advertise it now, if it is not less than
+                        * current one.
+                        * "Lots" means "at least twice" here.
+                        */
+                       if (new_window && new_window >= 2 * rcv_window_now)
+                               tcp_send_ack(sk);
+               }
+       }
+}
+
+static int mptcp_sub_send_fin(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sk_buff *skb = tcp_write_queue_tail(sk);
+       int mss_now;
+
+       /* Optimization, tack on the FIN if we have a queue of
+        * unsent frames.  But be careful about outgoing SACKS
+        * and IP options.
+        */
+       mss_now = tcp_current_mss(sk);
+
+       if (tcp_send_head(sk) != NULL) {
+               TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_FIN;
+               TCP_SKB_CB(skb)->end_seq++;
+               tp->write_seq++;
+       } else {
+               skb = alloc_skb_fclone(MAX_TCP_HEADER, GFP_ATOMIC);
+               if (!skb)
+                       return 1;
+
+               /* Reserve space for headers and prepare control bits. */
+               skb_reserve(skb, MAX_TCP_HEADER);
+               /* FIN eats a sequence byte, write_seq advanced by tcp_queue_skb(). */
+               tcp_init_nondata_skb(skb, tp->write_seq,
+                                    TCPHDR_ACK | TCPHDR_FIN);
+               tcp_queue_skb(sk, skb);
+       }
+       __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_OFF);
+
+       return 0;
+}
+
+void mptcp_sub_close_wq(struct work_struct *work)
+{
+       struct mptcp_tcp_sock *mptcp = container_of(work, struct mptcp_tcp_sock, work.work);
+       struct tcp_sock *tp = mptcp->tp;
+       struct sock *sk = (struct sock *)tp;
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+
+       mutex_lock(&tp->mpcb->mpcb_mutex);
+       lock_sock_nested(meta_sk, SINGLE_DEPTH_NESTING);
+
+       if (sock_flag(sk, SOCK_DEAD))
+               goto exit;
+
+       /* We come from tcp_disconnect. We are sure that meta_sk is set */
+       if (!tp->mpc) {
+               tp->closing = 1;
+               sock_rps_reset_flow(sk);
+               tcp_close(sk, 0);
+               goto exit;
+       }
+
+       if (meta_sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) {
+               tp->closing = 1;
+               sock_rps_reset_flow(sk);
+               tcp_close(sk, 0);
+       } else if (tcp_close_state(sk)) {
+               sk->sk_shutdown |= SEND_SHUTDOWN;
+               tcp_send_fin(sk);
+       }
+
+exit:
+       release_sock(meta_sk);
+       mutex_unlock(&tp->mpcb->mpcb_mutex);
+       sock_put(sk);
+}
+
+void mptcp_sub_close(struct sock *sk, unsigned long delay)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct delayed_work *work = &tcp_sk(sk)->mptcp->work;
+
+       /* We are already closing - e.g., call from sock_def_error_report upon
+        * tcp_disconnect in tcp_close.
+        */
+       if (tp->closing)
+               return;
+
+       /* Work already scheduled ? */
+       if (work_pending(&work->work)) {
+               /* Work present - who will be first ? */
+               if (jiffies + delay > work->timer.expires)
+                       return;
+
+               /* Try canceling - if it fails, work will be executed soon */
+               if (!cancel_delayed_work(work))
+                       return;
+               sock_put(sk);
+       }
+
+       if (!delay) {
+               unsigned char old_state = sk->sk_state;
+
+               /* If we are in user-context we can directly do the closing
+                * procedure. No need to schedule a work-queue.
+                */
+               if (!in_softirq()) {
+                       if (sock_flag(sk, SOCK_DEAD))
+                               return;
+
+                       if (!tp->mpc) {
+                               tp->closing = 1;
+                               sock_rps_reset_flow(sk);
+                               tcp_close(sk, 0);
+                               return;
+                       }
+
+                       if (mptcp_meta_sk(sk)->sk_shutdown == SHUTDOWN_MASK ||
+                           sk->sk_state == TCP_CLOSE) {
+                               tp->closing = 1;
+                               sock_rps_reset_flow(sk);
+                               tcp_close(sk, 0);
+                       } else if (tcp_close_state(sk)) {
+                               sk->sk_shutdown |= SEND_SHUTDOWN;
+                               tcp_send_fin(sk);
+                       }
+
+                       return;
+               }
+
+               /* We directly send the FIN. Because it may take so a long time,
+                * untile the work-queue will get scheduled...
+                *
+                * If mptcp_sub_send_fin returns 1, it failed and thus we reset
+                * the old state so that tcp_close will finally send the fin
+                * in user-context.
+                */
+               if (!sk->sk_err && old_state != TCP_CLOSE &&
+                   tcp_close_state(sk) && mptcp_sub_send_fin(sk)) {
+                       if (old_state == TCP_ESTABLISHED)
+                               TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
+                       sk->sk_state = old_state;
+               }
+       }
+
+       sock_hold(sk);
+       queue_delayed_work(mptcp_wq, work, delay);
+}
+
+void mptcp_sub_force_close(struct sock *sk)
+{
+       /* The below tcp_done may have freed the socket, if he is already dead.
+        * Thus, we are not allowed to access it afterwards. That's why
+        * we have to store the dead-state in this local variable.
+        */
+       int sock_is_dead = sock_flag(sk, SOCK_DEAD);
+
+       tcp_sk(sk)->mp_killed = 1;
+
+       if (sk->sk_state != TCP_CLOSE)
+               tcp_done(sk);
+
+       if (!sock_is_dead)
+               mptcp_sub_close(sk, 0);
+}
+EXPORT_SYMBOL(mptcp_sub_force_close);
+
+/* Update the mpcb send window, based on the contributions
+ * of each subflow
+ */
+void mptcp_update_sndbuf(struct mptcp_cb *mpcb)
+{
+       struct sock *meta_sk = mpcb->meta_sk, *sk;
+       int new_sndbuf = 0, old_sndbuf = meta_sk->sk_sndbuf;
+       mptcp_for_each_sk(mpcb, sk) {
+               if (!mptcp_sk_can_send(sk))
+                       continue;
+
+               new_sndbuf += sk->sk_sndbuf;
+
+               if (new_sndbuf > sysctl_tcp_wmem[2] || new_sndbuf < 0) {
+                       new_sndbuf = sysctl_tcp_wmem[2];
+                       break;
+               }
+       }
+       meta_sk->sk_sndbuf = max(min(new_sndbuf, sysctl_tcp_wmem[2]), meta_sk->sk_sndbuf);
+
+       /* The subflow's call to sk_write_space in tcp_new_space ends up in
+        * mptcp_write_space.
+        * It has nothing to do with waking up the application.
+        * So, we do it here.
+        */
+       if (old_sndbuf != meta_sk->sk_sndbuf)
+               meta_sk->sk_write_space(meta_sk);
+}
+
+void mptcp_close(struct sock *meta_sk, long timeout)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sock *sk_it, *tmpsk;
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       struct sk_buff *skb;
+       int data_was_unread = 0;
+       int state;
+
+       mptcp_debug("%s: Close of meta_sk with tok %#x\n",
+                   __func__, mpcb->mptcp_loc_token);
+
+       mutex_lock(&mpcb->mpcb_mutex);
+       lock_sock(meta_sk);
+
+       if (meta_tp->inside_tk_table) {
+               /* Detach the mpcb from the token hashtable */
+               mptcp_hash_remove_bh(meta_tp);
+               reqsk_queue_destroy(&inet_csk(meta_sk)->icsk_accept_queue);
+       }
+
+       meta_sk->sk_shutdown = SHUTDOWN_MASK;
+       /* We need to flush the recv. buffs.  We do this only on the
+        * descriptor close, not protocol-sourced closes, because the
+        * reader process may not have drained the data yet!
+        */
+       while ((skb = __skb_dequeue(&meta_sk->sk_receive_queue)) != NULL) {
+               u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
+                         tcp_hdr(skb)->fin;
+               data_was_unread += len;
+               __kfree_skb(skb);
+       }
+
+       sk_mem_reclaim(meta_sk);
+
+       /* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
+       if (meta_sk->sk_state == TCP_CLOSE) {
+               mptcp_for_each_sk_safe(mpcb, sk_it, tmpsk) {
+                       if (tcp_sk(sk_it)->send_mp_fclose)
+                               continue;
+                       mptcp_sub_close(sk_it, 0);
+               }
+               goto adjudge_to_death;
+       }
+
+       if (data_was_unread) {
+               /* Unread data was tossed, zap the connection. */
+               NET_INC_STATS_USER(sock_net(meta_sk), LINUX_MIB_TCPABORTONCLOSE);
+               tcp_set_state(meta_sk, TCP_CLOSE);
+               tcp_send_active_reset(meta_sk, meta_sk->sk_allocation);
+       } else if (sock_flag(meta_sk, SOCK_LINGER) && !meta_sk->sk_lingertime) {
+               /* Check zero linger _after_ checking for unread data. */
+               meta_sk->sk_prot->disconnect(meta_sk, 0);
+               NET_INC_STATS_USER(sock_net(meta_sk), LINUX_MIB_TCPABORTONDATA);
+       } else if (tcp_close_state(meta_sk)) {
+               mptcp_send_fin(meta_sk);
+       } else if (meta_tp->snd_una == meta_tp->write_seq) {
+               /* The DATA_FIN has been sent and acknowledged
+                * (e.g., by sk_shutdown). Close all the other subflows
+                */
+               mptcp_for_each_sk_safe(mpcb, sk_it, tmpsk) {
+                       unsigned long delay = 0;
+                       /* If we are the passive closer, don't trigger
+                        * subflow-fin until the subflow has been finned
+                        * by the peer. - thus we add a delay
+                        */
+                       if (mpcb->passive_close &&
+                           sk_it->sk_state == TCP_ESTABLISHED)
+                               delay = inet_csk(sk_it)->icsk_rto << 3;
+
+                       mptcp_sub_close(sk_it, delay);
+               }
+       }
+
+       sk_stream_wait_close(meta_sk, timeout);
+
+adjudge_to_death:
+       state = meta_sk->sk_state;
+       sock_hold(meta_sk);
+       sock_orphan(meta_sk);
+
+       /* socket will be freed after mptcp_close - we have to prevent
+        * access from the subflows.
+        */
+       mptcp_for_each_sk(mpcb, sk_it) {
+               /* Similar to sock_orphan, but we don't set it DEAD, because
+                * the callbacks are still set and must be called.
+                */
+               write_lock_bh(&sk_it->sk_callback_lock);
+               sk_set_socket(sk_it, NULL);
+               sk_it->sk_wq  = NULL;
+               write_unlock_bh(&sk_it->sk_callback_lock);
+       }
+
+       /* It is the last release_sock in its life. It will remove backlog. */
+       release_sock(meta_sk);
+
+       /* Now socket is owned by kernel and we acquire BH lock
+        * to finish close. No need to check for user refs.
+        */
+       local_bh_disable();
+       bh_lock_sock(meta_sk);
+       WARN_ON(sock_owned_by_user(meta_sk));
+
+       percpu_counter_inc(meta_sk->sk_prot->orphan_count);
+
+       /* Have we already been destroyed by a softirq or backlog? */
+       if (state != TCP_CLOSE && meta_sk->sk_state == TCP_CLOSE)
+               goto out;
+
+       /*      This is a (useful) BSD violating of the RFC. There is a
+        *      problem with TCP as specified in that the other end could
+        *      keep a socket open forever with no application left this end.
+        *      We use a 3 minute timeout (about the same as BSD) then kill
+        *      our end. If they send after that then tough - BUT: long enough
+        *      that we won't make the old 4*rto = almost no time - whoops
+        *      reset mistake.
+        *
+        *      Nope, it was not mistake. It is really desired behaviour
+        *      f.e. on http servers, when such sockets are useless, but
+        *      consume significant resources. Let's do it with special
+        *      linger2 option.                                 --ANK
+        */
+
+       if (meta_sk->sk_state == TCP_FIN_WAIT2) {
+               if (meta_tp->linger2 < 0) {
+                       tcp_set_state(meta_sk, TCP_CLOSE);
+                       tcp_send_active_reset(meta_sk, GFP_ATOMIC);
+                       NET_INC_STATS_BH(sock_net(meta_sk),
+                                        LINUX_MIB_TCPABORTONLINGER);
+               } else {
+                       const int tmo = tcp_fin_time(meta_sk);
+
+                       if (tmo > TCP_TIMEWAIT_LEN) {
+                               inet_csk_reset_keepalive_timer(meta_sk,
+                                                              tmo - TCP_TIMEWAIT_LEN);
+                       } else {
+                               tcp_time_wait(meta_sk, TCP_FIN_WAIT2, tmo);
+                               goto out;
+                       }
+               }
+       }
+       if (meta_sk->sk_state != TCP_CLOSE) {
+               sk_mem_reclaim(meta_sk);
+               if (tcp_too_many_orphans(meta_sk, 0)) {
+                       if (net_ratelimit())
+                               pr_info("MPTCP: too many of orphaned sockets\n");
+                       tcp_set_state(meta_sk, TCP_CLOSE);
+                       tcp_send_active_reset(meta_sk, GFP_ATOMIC);
+                       NET_INC_STATS_BH(sock_net(meta_sk),
+                                        LINUX_MIB_TCPABORTONMEMORY);
+               }
+       }
+
+
+       if (meta_sk->sk_state == TCP_CLOSE)
+               inet_csk_destroy_sock(meta_sk);
+       /* Otherwise, socket is reprieved until protocol close. */
+
+out:
+       bh_unlock_sock(meta_sk);
+       local_bh_enable();
+       mutex_unlock(&mpcb->mpcb_mutex);
+       sock_put(meta_sk); /* Taken by sock_hold */
+}
+
+void mptcp_disconnect(struct sock *sk)
+{
+       struct sock *subsk, *tmpsk;
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       __skb_queue_purge(&tp->mpcb->reinject_queue);
+
+       if (tp->inside_tk_table) {
+               mptcp_hash_remove_bh(tp);
+               reqsk_queue_destroy(&inet_csk(tp->meta_sk)->icsk_accept_queue);
+       }
+
+       local_bh_disable();
+       mptcp_for_each_sk_safe(tp->mpcb, subsk, tmpsk) {
+               /* The socket will get removed from the subsocket-list
+                * and made non-mptcp by setting mpc to 0.
+                *
+                * This is necessary, because tcp_disconnect assumes
+                * that the connection is completly dead afterwards.
+                * Thus we need to do a mptcp_del_sock. Due to this call
+                * we have to make it non-mptcp.
+                *
+                * We have to lock the socket, because we set mpc to 0.
+                * An incoming packet would take the subsocket's lock
+                * and go on into the receive-path.
+                * This would be a race.
+                */
+
+               bh_lock_sock(subsk);
+               mptcp_del_sock(subsk);
+               reset_mpc(tcp_sk(subsk));
+               mptcp_sub_force_close(subsk);
+               bh_unlock_sock(subsk);
+       }
+       local_bh_enable();
+
+       tp->was_meta_sk = 1;
+       reset_mpc(tp);
+}
+
+
+/* Returns 1 if we should enable MPTCP for that socket. */
+int mptcp_doit(struct sock *sk)
+{
+       /* Do not allow MPTCP enabling if the MPTCP initialization failed */
+       if (mptcp_init_failed)
+               return 0;
+
+       if (sysctl_mptcp_enabled == MPTCP_APP && !tcp_sk(sk)->mptcp_enabled)
+               return 0;
+
+       /* Socket may already be established (e.g., called from tcp_recvmsg) */
+       if (tcp_sk(sk)->mpc || tcp_sk(sk)->request_mptcp)
+               return 1;
+
+       /* Don't do mptcp over loopback */
+       if (sk->sk_family == AF_INET &&
+           (ipv4_is_loopback(inet_sk(sk)->inet_daddr) ||
+            ipv4_is_loopback(inet_sk(sk)->inet_saddr)))
+               return 0;
+#if IS_ENABLED(CONFIG_IPV6)
+       if (sk->sk_family == AF_INET6 &&
+           (ipv6_addr_loopback(&sk->sk_v6_daddr) ||
+            ipv6_addr_loopback(&inet6_sk(sk)->saddr)))
+               return 0;
+#endif
+       if (mptcp_v6_is_v4_mapped(sk) &&
+           ipv4_is_loopback(inet_sk(sk)->inet_saddr))
+               return 0;
+
+#ifdef CONFIG_TCP_MD5SIG
+       /* If TCP_MD5SIG is enabled, do not do MPTCP - there is no Option-Space */
+       if (tcp_sk(sk)->af_specific->md5_lookup(sk, sk))
+               return 0;
+#endif
+
+       return 1;
+}
+
+int mptcp_create_master_sk(struct sock *meta_sk, __u64 remote_key, u32 window)
+{
+       struct tcp_sock *master_tp;
+       struct sock *master_sk;
+
+       if (mptcp_alloc_mpcb(meta_sk, remote_key, window))
+               goto err_alloc_mpcb;
+
+       master_sk = tcp_sk(meta_sk)->mpcb->master_sk;
+       master_tp = tcp_sk(master_sk);
+
+       if (mptcp_add_sock(meta_sk, master_sk, 0, 0, GFP_ATOMIC))
+               goto err_add_sock;
+
+       if (__inet_inherit_port(meta_sk, master_sk) < 0)
+               goto err_add_sock;
+
+       meta_sk->sk_prot->unhash(meta_sk);
+
+       if (master_sk->sk_family == AF_INET || mptcp_v6_is_v4_mapped(master_sk))
+               __inet_hash_nolisten(master_sk, NULL);
+#if IS_ENABLED(CONFIG_IPV6)
+       else
+               __inet6_hash(master_sk, NULL);
+#endif
+
+       master_tp->mptcp->init_rcv_wnd = master_tp->rcv_wnd;
+
+       return 0;
+
+err_add_sock:
+       mptcp_fallback_meta_sk(meta_sk);
+
+       inet_csk_prepare_forced_close(master_sk);
+       tcp_done(master_sk);
+       inet_csk_prepare_forced_close(meta_sk);
+       tcp_done(meta_sk);
+
+err_alloc_mpcb:
+       return -ENOBUFS;
+}
+
+int mptcp_check_req_master(struct sock *sk, struct sock *child,
+                          struct request_sock *req,
+                          struct request_sock **prev,
+                          struct mptcp_options_received *mopt)
+{
+       struct tcp_sock *child_tp = tcp_sk(child);
+       struct sock *meta_sk = child;
+       struct mptcp_cb *mpcb;
+       struct mptcp_request_sock *mtreq;
+
+       if (!tcp_rsk(req)->saw_mpc)
+               return 1;
+
+       /* Just set this values to pass them to mptcp_alloc_mpcb */
+       mtreq = mptcp_rsk(req);
+       child_tp->mptcp_loc_key = mtreq->mptcp_loc_key;
+       child_tp->mptcp_loc_token = mtreq->mptcp_loc_token;
+
+       if (mptcp_create_master_sk(meta_sk, mtreq->mptcp_rem_key,
+                                  child_tp->snd_wnd))
+               return -ENOBUFS;
+
+       child = tcp_sk(child)->mpcb->master_sk;
+       child_tp = tcp_sk(child);
+       mpcb = child_tp->mpcb;
+
+       child_tp->mptcp->snt_isn = tcp_rsk(req)->snt_isn;
+       child_tp->mptcp->rcv_isn = tcp_rsk(req)->rcv_isn;
+
+       mpcb->dss_csum = mtreq->dss_csum;
+       mpcb->server_side = 1;
+
+       /* Will be moved to ESTABLISHED by  tcp_rcv_state_process() */
+       mptcp_update_metasocket(child, meta_sk);
+
+       /* Needs to be done here additionally, because when accepting a
+        * new connection we pass by __reqsk_free and not reqsk_free.
+        */
+       mptcp_reqsk_remove_tk(req);
+
+        /* Hold when creating the meta-sk in tcp_vX_syn_recv_sock. */
+       sock_put(meta_sk);
+
+       inet_csk_reqsk_queue_unlink(sk, req, prev);
+       inet_csk_reqsk_queue_removed(sk, req);
+       inet_csk_reqsk_queue_add(sk, req, meta_sk);
+
+       return 0;
+}
+
+struct sock *mptcp_check_req_child(struct sock *meta_sk, struct sock *child,
+                                  struct request_sock *req,
+                                  struct request_sock **prev,
+                                  struct mptcp_options_received *mopt)
+{
+       struct tcp_sock *child_tp = tcp_sk(child);
+       struct mptcp_request_sock *mtreq = mptcp_rsk(req);
+       struct mptcp_cb *mpcb = mtreq->mpcb;
+       u8 hash_mac_check[20];
+
+       child_tp->inside_tk_table = 0;
+
+       if (!mopt->join_ack)
+               goto teardown;
+
+       mptcp_hmac_sha1((u8 *)&mpcb->mptcp_rem_key,
+                       (u8 *)&mpcb->mptcp_loc_key,
+                       (u8 *)&mtreq->mptcp_rem_nonce,
+                       (u8 *)&mtreq->mptcp_loc_nonce,
+                       (u32 *)hash_mac_check);
+
+       if (memcmp(hash_mac_check, (char *)&mopt->mptcp_recv_mac, 20))
+               goto teardown;
+
+       /* Point it to the same struct socket and wq as the meta_sk */
+       sk_set_socket(child, meta_sk->sk_socket);
+       child->sk_wq = meta_sk->sk_wq;
+
+       if (mptcp_add_sock(meta_sk, child, mtreq->loc_id, mtreq->rem_id, GFP_ATOMIC)) {
+               reset_mpc(child_tp); /* Has been inherited, but now
+                                     * child_tp->mptcp is NULL
+                                     */
+               /* TODO when we support acking the third ack for new subflows,
+                * we should silently discard this third ack, by returning NULL.
+                *
+                * Maybe, at the retransmission we will have enough memory to
+                * fully add the socket to the meta-sk.
+                */
+               goto teardown;
+       }
+
+       /* The child is a clone of the meta socket, we must now reset
+        * some of the fields
+        */
+       child_tp->mptcp->rcv_low_prio = mtreq->low_prio;
+
+       /* We should allow proper increase of the snd/rcv-buffers. Thus, we
+        * use the original values instead of the bloated up ones from the
+        * clone.
+        */
+       child->sk_sndbuf = mpcb->orig_sk_sndbuf;
+       child->sk_rcvbuf = mpcb->orig_sk_rcvbuf;
+
+       child_tp->mptcp->slave_sk = 1;
+       child_tp->mptcp->snt_isn = tcp_rsk(req)->snt_isn;
+       child_tp->mptcp->rcv_isn = tcp_rsk(req)->rcv_isn;
+       child_tp->mptcp->init_rcv_wnd = req->rcv_wnd;
+
+       child_tp->tsq_flags = 0;
+
+       /* Subflows do not use the accept queue, as they
+        * are attached immediately to the mpcb.
+        */
+       inet_csk_reqsk_queue_drop(meta_sk, req, prev);
+       return child;
+
+teardown:
+       /* Drop this request - sock creation failed. */
+       inet_csk_reqsk_queue_drop(meta_sk, req, prev);
+       inet_csk_prepare_forced_close(child);
+       tcp_done(child);
+       return meta_sk;
+}
+
+int mptcp_time_wait(struct sock *sk, struct tcp_timewait_sock *tw)
+{
+       struct mptcp_tw *mptw;
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct mptcp_cb *mpcb = tp->mpcb;
+
+       /* Alloc MPTCP-tw-sock */
+       mptw = kmem_cache_alloc(mptcp_tw_cache, GFP_ATOMIC);
+       if (!mptw)
+               return -ENOBUFS;
+
+       atomic_inc(&mpcb->mpcb_refcnt);
+
+       tw->mptcp_tw = mptw;
+       mptw->loc_key = mpcb->mptcp_loc_key;
+       mptw->meta_tw = mpcb->in_time_wait;
+       if (mptw->meta_tw) {
+               mptw->rcv_nxt = mptcp_get_rcv_nxt_64(mptcp_meta_tp(tp));
+               if (mpcb->mptw_state != TCP_TIME_WAIT)
+                       mptw->rcv_nxt++;
+       }
+       rcu_assign_pointer(mptw->mpcb, mpcb);
+
+       spin_lock(&mpcb->tw_lock);
+       list_add_rcu(&mptw->list, &tp->mpcb->tw_list);
+       mptw->in_list = 1;
+       spin_unlock(&mpcb->tw_lock);
+
+       return 0;
+}
+
+void mptcp_twsk_destructor(struct tcp_timewait_sock *tw)
+{
+       struct mptcp_cb *mpcb;
+
+       rcu_read_lock();
+       mpcb = rcu_dereference(tw->mptcp_tw->mpcb);
+
+       /* If we are still holding a ref to the mpcb, we have to remove ourself
+        * from the list and drop the ref properly.
+        */
+       if (mpcb && atomic_inc_not_zero(&mpcb->mpcb_refcnt)) {
+               spin_lock(&mpcb->tw_lock);
+               if (tw->mptcp_tw->in_list) {
+                       list_del_rcu(&tw->mptcp_tw->list);
+                       tw->mptcp_tw->in_list = 0;
+               }
+               spin_unlock(&mpcb->tw_lock);
+
+               /* Twice, because we increased it above */
+               mptcp_mpcb_put(mpcb);
+               mptcp_mpcb_put(mpcb);
+       }
+
+       rcu_read_unlock();
+
+       kmem_cache_free(mptcp_tw_cache, tw->mptcp_tw);
+}
+
+/* Updates the rcv_nxt of the time-wait-socks and allows them to ack a
+ * data-fin.
+ */
+void mptcp_update_tw_socks(const struct tcp_sock *tp, int state)
+{
+       struct mptcp_tw *mptw;
+
+       /* Used for sockets that go into tw after the meta
+        * (see mptcp_time_wait())
+        */
+       tp->mpcb->in_time_wait = 1;
+       tp->mpcb->mptw_state = state;
+
+       /* Update the time-wait-sock's information */
+       rcu_read_lock_bh();
+       list_for_each_entry_rcu(mptw, &tp->mpcb->tw_list, list) {
+               mptw->meta_tw = 1;
+               mptw->rcv_nxt = mptcp_get_rcv_nxt_64(tp);
+
+               /* We want to ack a DATA_FIN, but are yet in FIN_WAIT_2 -
+                * pretend as if the DATA_FIN has already reached us, that way
+                * the checks in tcp_timewait_state_process will be good as the
+                * DATA_FIN comes in.
+                */
+               if (state != TCP_TIME_WAIT)
+                       mptw->rcv_nxt++;
+       }
+       rcu_read_unlock_bh();
+}
+
+void mptcp_tsq_flags(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+
+       /* It will be handled as a regular deferred-call */
+       if (is_meta_sk(sk))
+               return;
+
+       if (list_empty(&tp->mptcp->cb_list)) {
+               list_add(&tp->mptcp->cb_list, &tp->mpcb->callback_list);
+               /* We need to hold it here, as the sock_hold is not assured
+                * by the release_sock as it is done in regular TCP.
+                *
+                * The subsocket may get inet_csk_destroy'd while it is inside
+                * the callback_list.
+                */
+               sock_hold(sk);
+       }
+
+       if (!test_and_set_bit(MPTCP_SUB_DEFERRED, &tcp_sk(meta_sk)->tsq_flags))
+               sock_hold(meta_sk);
+}
+
+void mptcp_tsq_sub_deferred(struct sock *meta_sk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_tcp_sock *mptcp, *tmp;
+
+       BUG_ON(!is_meta_sk(meta_sk) && !meta_tp->was_meta_sk);
+
+       __sock_put(meta_sk);
+       list_for_each_entry_safe(mptcp, tmp, &meta_tp->mpcb->callback_list, cb_list) {
+               struct tcp_sock *tp = mptcp->tp;
+               struct sock *sk = (struct sock *)tp;
+
+               list_del_init(&mptcp->cb_list);
+               sk->sk_prot->release_cb(sk);
+               /* Final sock_put (cfr. mptcp_tsq_flags */
+               sock_put(sk);
+       }
+}
+
+struct workqueue_struct *mptcp_wq;
+EXPORT_SYMBOL(mptcp_wq);
+
+/* Output /proc/net/mptcp */
+static int mptcp_pm_seq_show(struct seq_file *seq, void *v)
+{
+       struct tcp_sock *meta_tp;
+       struct net *net = seq->private;
+       int i, n = 0;
+
+       seq_printf(seq, "  sl  loc_tok  rem_tok  v6 "
+                  "local_address                         "
+                  "remote_address                        "
+                  "st ns tx_queue rx_queue inode");
+       seq_putc(seq, '\n');
+
+       for (i = 0; i < MPTCP_HASH_SIZE; i++) {
+               struct hlist_nulls_node *node;
+               rcu_read_lock_bh();
+               hlist_nulls_for_each_entry_rcu(meta_tp, node,
+                                              &tk_hashtable[i], tk_table) {
+                       struct mptcp_cb *mpcb = meta_tp->mpcb;
+                       struct sock *meta_sk = (struct sock *)meta_tp;
+                       struct inet_sock *isk = inet_sk(meta_sk);
+
+                       if (!meta_tp->mpc || !net_eq(net, sock_net(meta_sk)))
+                               continue;
+
+                       seq_printf(seq, "%4d: %04X %04X ", n++,
+                                  mpcb->mptcp_loc_token,
+                                  mpcb->mptcp_rem_token);
+                       if (meta_sk->sk_family == AF_INET ||
+                           mptcp_v6_is_v4_mapped(meta_sk)) {
+                               seq_printf(seq, " 0 %08X:%04X                         %08X:%04X                        ",
+                                          isk->inet_saddr,
+                                          ntohs(isk->inet_sport),
+                                          isk->inet_daddr,
+                                          ntohs(isk->inet_dport));
+#if IS_ENABLED(CONFIG_IPV6)
+                       } else if (meta_sk->sk_family == AF_INET6) {
+                               struct in6_addr *src = &isk->pinet6->saddr;
+                               struct in6_addr *dst = &meta_sk->sk_v6_daddr;
+                               seq_printf(seq, " 1 %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X",
+                                          src->s6_addr32[0], src->s6_addr32[1],
+                                          src->s6_addr32[2], src->s6_addr32[3],
+                                          ntohs(isk->inet_sport),
+                                          dst->s6_addr32[0], dst->s6_addr32[1],
+                                          dst->s6_addr32[2], dst->s6_addr32[3],
+                                          ntohs(isk->inet_dport));
+#endif
+                       }
+                       seq_printf(seq, " %02X %02X %08X:%08X %lu",
+                                  meta_sk->sk_state, mpcb->cnt_subflows,
+                                  meta_tp->write_seq - meta_tp->snd_una,
+                                  max_t(int, meta_tp->rcv_nxt -
+                                        meta_tp->copied_seq, 0),
+                                  sock_i_ino(meta_sk));
+                       seq_putc(seq, '\n');
+               }
+               rcu_read_unlock_bh();
+       }
+
+       return 0;
+}
+
+static int mptcp_pm_seq_open(struct inode *inode, struct file *file)
+{
+       return single_open_net(inode, file, mptcp_pm_seq_show);
+}
+
+static const struct file_operations mptcp_pm_seq_fops = {
+       .owner = THIS_MODULE,
+       .open = mptcp_pm_seq_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release_net,
+};
+
+static int mptcp_pm_init_net(struct net *net)
+{
+       if (!proc_create("mptcp", S_IRUGO, net->proc_net, &mptcp_pm_seq_fops))
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void mptcp_pm_exit_net(struct net *net)
+{
+       remove_proc_entry("mptcp", net->proc_net);
+}
+
+static struct pernet_operations mptcp_pm_proc_ops = {
+       .init = mptcp_pm_init_net,
+       .exit = mptcp_pm_exit_net,
+};
+
+/* General initialization of mptcp */
+void __init mptcp_init(void)
+{
+       int i;
+       struct ctl_table_header *mptcp_sysctl;
+
+       mptcp_sock_cache = kmem_cache_create("mptcp_sock",
+                                            sizeof(struct mptcp_tcp_sock),
+                                            0, SLAB_HWCACHE_ALIGN,
+                                            NULL);
+       if (!mptcp_sock_cache)
+               goto mptcp_sock_cache_failed;
+
+       mptcp_cb_cache = kmem_cache_create("mptcp_cb", sizeof(struct mptcp_cb),
+                                          0, SLAB_DESTROY_BY_RCU|SLAB_HWCACHE_ALIGN,
+                                          NULL);
+       if (!mptcp_cb_cache)
+               goto mptcp_cb_cache_failed;
+
+       mptcp_tw_cache = kmem_cache_create("mptcp_tw", sizeof(struct mptcp_tw),
+                                          0, SLAB_DESTROY_BY_RCU|SLAB_HWCACHE_ALIGN,
+                                          NULL);
+       if (!mptcp_tw_cache)
+               goto mptcp_tw_cache_failed;
+
+       get_random_bytes(mptcp_secret, sizeof(mptcp_secret));
+
+       mptcp_wq = alloc_workqueue("mptcp_wq", WQ_UNBOUND | WQ_MEM_RECLAIM, 8);
+       if (!mptcp_wq)
+               goto alloc_workqueue_failed;
+
+       for (i = 0; i < MPTCP_HASH_SIZE; i++) {
+               INIT_HLIST_NULLS_HEAD(&tk_hashtable[i], i);
+               INIT_LIST_HEAD(&mptcp_reqsk_htb[i]);
+               INIT_HLIST_NULLS_HEAD(&mptcp_reqsk_tk_htb[i], i);
+       }
+
+       spin_lock_init(&mptcp_reqsk_hlock);
+       spin_lock_init(&mptcp_tk_hashlock);
+
+       if (register_pernet_subsys(&mptcp_pm_proc_ops))
+               goto pernet_failed;
+
+#if IS_ENABLED(CONFIG_IPV6)
+       if (mptcp_pm_v6_init())
+               goto mptcp_pm_v6_failed;
+#endif
+       if (mptcp_pm_v4_init())
+               goto mptcp_pm_v4_failed;
+
+       mptcp_sysctl = register_net_sysctl(&init_net, "net/mptcp", mptcp_table);
+       if (!mptcp_sysctl)
+               goto register_sysctl_failed;
+
+       if (mptcp_register_path_manager(&mptcp_pm_default))
+               goto register_pm_failed;
+
+       pr_info("MPTCP: Stable release v0.89.0-rc");
+
+       mptcp_init_failed = false;
+
+       return;
+
+register_pm_failed:
+       unregister_net_sysctl_table(mptcp_sysctl);
+register_sysctl_failed:
+       mptcp_pm_v4_undo();
+mptcp_pm_v4_failed:
+#if IS_ENABLED(CONFIG_IPV6)
+       mptcp_pm_v6_undo();
+mptcp_pm_v6_failed:
+#endif
+       unregister_pernet_subsys(&mptcp_pm_proc_ops);
+pernet_failed:
+       destroy_workqueue(mptcp_wq);
+alloc_workqueue_failed:
+       kmem_cache_destroy(mptcp_tw_cache);
+mptcp_tw_cache_failed:
+       kmem_cache_destroy(mptcp_cb_cache);
+mptcp_cb_cache_failed:
+       kmem_cache_destroy(mptcp_sock_cache);
+mptcp_sock_cache_failed:
+       mptcp_init_failed = true;
+}
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_fullmesh.c linux-3.14.45/net/mptcp/mptcp_fullmesh.c
--- linux-3.14.45.orig/net/mptcp/mptcp_fullmesh.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_fullmesh.c    2015-06-24 14:15:48.891862483 +0200
@@ -0,0 +1,1313 @@
+#include <linux/module.h>
+
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/mptcp_v6.h>
+#include <net/addrconf.h>
+#endif
+
+enum {
+       MPTCP_EVENT_ADD = 1,
+       MPTCP_EVENT_DEL,
+       MPTCP_EVENT_MOD,
+};
+
+struct mptcp_loc_addr {
+       struct mptcp_loc4 locaddr4[MPTCP_MAX_ADDR];
+       u8 loc4_bits;
+       u8 next_v4_index;
+
+       struct mptcp_loc6 locaddr6[MPTCP_MAX_ADDR];
+       u8 loc6_bits;
+       u8 next_v6_index;
+};
+
+struct mptcp_addr_event {
+       struct list_head list;
+       unsigned short  family;
+       u8      code:7,
+               low_prio:1;
+       union inet_addr addr;
+};
+
+struct fullmesh_priv {
+       /* Worker struct for subflow establishment */
+       struct work_struct subflow_work;
+       /* Delayed worker, when the routing-tables are not yet ready. */
+       struct delayed_work subflow_retry_work;
+
+       struct mptcp_cb *mpcb;
+
+       u16 remove_addrs; /* Addresses to remove */
+       u8 announced_addrs_v4; /* IPv4 Addresses we did announce */
+       u8 announced_addrs_v6; /* IPv4 Addresses we did announce */
+
+       u8      add_addr; /* Are we sending an add_addr? */
+};
+
+struct mptcp_fm_ns {
+       struct mptcp_loc_addr __rcu *local;
+       spinlock_t local_lock; /* Protecting the above pointer */
+       struct list_head events;
+       struct delayed_work address_worker;
+
+       struct net *net;
+};
+
+static struct mptcp_pm_ops full_mesh __read_mostly;
+
+static struct mptcp_fm_ns *fm_get_ns(struct net *net)
+{
+       return (struct mptcp_fm_ns *)net->mptcp.path_managers[MPTCP_PM_FULLMESH];
+}
+
+static void full_mesh_create_subflows(struct sock *meta_sk);
+
+static void retry_subflow_worker(struct work_struct *work)
+{
+       struct delayed_work *delayed_work = container_of(work,
+                                                        struct delayed_work,
+                                                        work);
+       struct fullmesh_priv *pm_priv = container_of(delayed_work,
+                                                    struct fullmesh_priv,
+                                                    subflow_retry_work);
+       struct mptcp_cb *mpcb = pm_priv->mpcb;
+       struct sock *meta_sk = mpcb->meta_sk;
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(sock_net(meta_sk));
+       int iter = 0, i;
+
+       /* We need a local (stable) copy of the address-list. Really, it is not
+        * such a big deal, if the address-list is not 100% up-to-date.
+        */
+       rcu_read_lock_bh();
+       mptcp_local = rcu_dereference_bh(fm_ns->local);
+       mptcp_local = kmemdup(mptcp_local, sizeof(*mptcp_local), GFP_ATOMIC);
+       rcu_read_unlock_bh();
+
+       if (!mptcp_local)
+               return;
+
+next_subflow:
+       if (iter) {
+               release_sock(meta_sk);
+               mutex_unlock(&mpcb->mpcb_mutex);
+
+               yield();
+       }
+       mutex_lock(&mpcb->mpcb_mutex);
+       lock_sock_nested(meta_sk, SINGLE_DEPTH_NESTING);
+
+       iter++;
+
+       if (sock_flag(meta_sk, SOCK_DEAD))
+               goto exit;
+
+       mptcp_for_each_bit_set(mpcb->rem4_bits, i) {
+               struct mptcp_rem4 *rem = &mpcb->remaddr4[i];
+               /* Do we need to retry establishing a subflow ? */
+               if (rem->retry_bitfield) {
+                       int i = mptcp_find_free_index(~rem->retry_bitfield);
+
+                       rem->bitfield |= (1 << i);
+                       rem->retry_bitfield &= ~(1 << i);
+
+                       mptcp_init4_subsockets(meta_sk, &mptcp_local->locaddr4[i], rem);
+                       goto next_subflow;
+               }
+       }
+
+#if IS_ENABLED(CONFIG_IPV6)
+       mptcp_for_each_bit_set(mpcb->rem6_bits, i) {
+               struct mptcp_rem6 *rem = &mpcb->remaddr6[i];
+
+               /* Do we need to retry establishing a subflow ? */
+               if (rem->retry_bitfield) {
+                       int i = mptcp_find_free_index(~rem->retry_bitfield);
+
+                       rem->bitfield |= (1 << i);
+                       rem->retry_bitfield &= ~(1 << i);
+
+                       mptcp_init6_subsockets(meta_sk, &mptcp_local->locaddr6[i], rem);
+                       goto next_subflow;
+               }
+       }
+#endif
+
+exit:
+       kfree(mptcp_local);
+       release_sock(meta_sk);
+       mutex_unlock(&mpcb->mpcb_mutex);
+       sock_put(meta_sk);
+}
+
+/**
+ * Create all new subflows, by doing calls to mptcp_initX_subsockets
+ *
+ * This function uses a goto next_subflow, to allow releasing the lock between
+ * new subflows and giving other processes a chance to do some work on the
+ * socket and potentially finishing the communication.
+ **/
+static void create_subflow_worker(struct work_struct *work)
+{
+       struct fullmesh_priv *pm_priv = container_of(work,
+                                                    struct fullmesh_priv,
+                                                    subflow_work);
+       struct mptcp_cb *mpcb = pm_priv->mpcb;
+       struct sock *meta_sk = mpcb->meta_sk;
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(sock_net(meta_sk));
+       int iter = 0, retry = 0;
+       int i;
+
+       /* We need a local (stable) copy of the address-list. Really, it is not
+        * such a big deal, if the address-list is not 100% up-to-date.
+        */
+       rcu_read_lock_bh();
+       mptcp_local = rcu_dereference_bh(fm_ns->local);
+       mptcp_local = kmemdup(mptcp_local, sizeof(*mptcp_local), GFP_ATOMIC);
+       rcu_read_unlock_bh();
+
+       if (!mptcp_local)
+               return;
+
+next_subflow:
+       if (iter) {
+               release_sock(meta_sk);
+               mutex_unlock(&mpcb->mpcb_mutex);
+
+               yield();
+       }
+       mutex_lock(&mpcb->mpcb_mutex);
+       lock_sock_nested(meta_sk, SINGLE_DEPTH_NESTING);
+
+       iter++;
+
+       if (sock_flag(meta_sk, SOCK_DEAD))
+               goto exit;
+
+       if (mpcb->master_sk &&
+           !tcp_sk(mpcb->master_sk)->mptcp->fully_established)
+               goto exit;
+
+       mptcp_for_each_bit_set(mpcb->rem4_bits, i) {
+               struct mptcp_rem4 *rem;
+               u8 remaining_bits;
+
+               rem = &mpcb->remaddr4[i];
+               remaining_bits = ~(rem->bitfield) & mptcp_local->loc4_bits;
+
+               /* Are there still combinations to handle? */
+               if (remaining_bits) {
+                       int i = mptcp_find_free_index(~remaining_bits);
+
+                       rem->bitfield |= (1 << i);
+
+                       /* If a route is not yet available then retry once */
+                       if (mptcp_init4_subsockets(meta_sk, &mptcp_local->locaddr4[i],
+                                                  rem) == -ENETUNREACH)
+                               retry = rem->retry_bitfield |= (1 << i);
+                       goto next_subflow;
+               }
+       }
+
+#if IS_ENABLED(CONFIG_IPV6)
+       mptcp_for_each_bit_set(mpcb->rem6_bits, i) {
+               struct mptcp_rem6 *rem;
+               u8 remaining_bits;
+
+               rem = &mpcb->remaddr6[i];
+               remaining_bits = ~(rem->bitfield) & mptcp_local->loc6_bits;
+
+               /* Are there still combinations to handle? */
+               if (remaining_bits) {
+                       int i = mptcp_find_free_index(~remaining_bits);
+
+                       rem->bitfield |= (1 << i);
+
+                       /* If a route is not yet available then retry once */
+                       if (mptcp_init6_subsockets(meta_sk, &mptcp_local->locaddr6[i],
+                                                  rem) == -ENETUNREACH)
+                               retry = rem->retry_bitfield |= (1 << i);
+                       goto next_subflow;
+               }
+       }
+#endif
+
+       if (retry && !delayed_work_pending(&pm_priv->subflow_retry_work)) {
+               sock_hold(meta_sk);
+               queue_delayed_work(mptcp_wq, &pm_priv->subflow_retry_work,
+                                  msecs_to_jiffies(MPTCP_SUBFLOW_RETRY_DELAY));
+       }
+
+exit:
+       kfree(mptcp_local);
+       release_sock(meta_sk);
+       mutex_unlock(&mpcb->mpcb_mutex);
+       sock_put(meta_sk);
+}
+
+static void update_remove_addrs(u8 addr_id, struct sock *meta_sk,
+                               struct mptcp_loc_addr *mptcp_local)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct fullmesh_priv *fmp = (struct fullmesh_priv *)&mpcb->mptcp_pm[0];
+       struct sock *sk;
+       int i;
+
+       fmp->remove_addrs |= (1 << addr_id);
+       /* v4 goes from 0 to MPTCP_MAX_ADDR, v6 beyond */
+       if (addr_id < MPTCP_MAX_ADDR) {
+               fmp->announced_addrs_v4 &= ~(1 << addr_id);
+
+               mptcp_for_each_bit_set(mpcb->rem4_bits, i) {
+                       mpcb->remaddr4[i].bitfield &= mptcp_local->loc4_bits;
+                       mpcb->remaddr4[i].retry_bitfield &= mptcp_local->loc4_bits;
+               }
+       } else {
+               fmp->announced_addrs_v6 &= ~(1 << (addr_id - MPTCP_MAX_ADDR));
+
+               mptcp_for_each_bit_set(mpcb->rem6_bits, i) {
+                       mpcb->remaddr6[i].bitfield &= mptcp_local->loc6_bits;
+                       mpcb->remaddr6[i].retry_bitfield &= mptcp_local->loc6_bits;
+               }
+       }
+
+       sk = mptcp_select_ack_sock(meta_sk, 0);
+       if (sk)
+               tcp_send_ack(sk);
+}
+
+static int mptcp_find_address(struct mptcp_loc_addr *mptcp_local,
+                             sa_family_t family, union inet_addr *addr)
+{
+       int i;
+       u8 loc_bits;
+       bool found = false;
+
+       if (family == AF_INET)
+               loc_bits = mptcp_local->loc4_bits;
+       else
+               loc_bits = mptcp_local->loc6_bits;
+
+       mptcp_for_each_bit_set(loc_bits, i) {
+               if (family == AF_INET &&
+                   mptcp_local->locaddr4[i].addr.s_addr == addr->in.s_addr) {
+                       found = true;
+                       break;
+               }
+               if (family == AF_INET6 &&
+                   ipv6_addr_equal(&mptcp_local->locaddr6[i].addr,
+                                   &addr->in6)) {
+                       found = true;
+                       break;
+               }
+       }
+
+       if (!found)
+               return -1;
+
+       return i;
+}
+
+static void mptcp_address_worker(struct work_struct *work)
+{
+       struct delayed_work *delayed_work = container_of(work,
+                                                        struct delayed_work,
+                                                        work);
+       struct mptcp_fm_ns *fm_ns = container_of(delayed_work,
+                                                struct mptcp_fm_ns,
+                                                address_worker);
+       struct net *net = fm_ns->net;
+       struct mptcp_addr_event *event = NULL;
+       struct mptcp_loc_addr *mptcp_local, *old;
+       int i, id = -1; /* id is used in the socket-code on a delete-event */
+       bool success; /* Used to indicate if we succeeded handling the event */
+
+next_event:
+       success = false;
+       kfree(event);
+
+       /* First, let's dequeue an event from our event-list */
+       rcu_read_lock_bh();
+       spin_lock(&fm_ns->local_lock);
+
+       event = list_first_entry_or_null(&fm_ns->events,
+                                        struct mptcp_addr_event, list);
+       if (!event) {
+               spin_unlock(&fm_ns->local_lock);
+               rcu_read_unlock_bh();
+               return;
+       }
+
+       list_del(&event->list);
+
+       mptcp_local = rcu_dereference_bh(fm_ns->local);
+
+       if (event->code == MPTCP_EVENT_DEL) {
+               id = mptcp_find_address(mptcp_local, event->family, &event->addr);
+
+               /* Not in the list - so we don't care */
+               if (id < 0)
+                       goto duno;
+
+               old = mptcp_local;
+               mptcp_local = kmemdup(mptcp_local, sizeof(*mptcp_local),
+                                     GFP_ATOMIC);
+               if (!mptcp_local)
+                       goto duno;
+
+               if (event->family == AF_INET)
+                       mptcp_local->loc4_bits &= ~(1 << id);
+               else
+                       mptcp_local->loc6_bits &= ~(1 << id);
+
+               rcu_assign_pointer(fm_ns->local, mptcp_local);
+               kfree(old);
+       } else {
+               int i = mptcp_find_address(mptcp_local, event->family, &event->addr);
+               int j = i;
+
+               if (j < 0) {
+                       /* Not in the list, so we have to find an empty slot */
+                       if (event->family == AF_INET)
+                               i = __mptcp_find_free_index(mptcp_local->loc4_bits, -1,
+                                                           mptcp_local->next_v4_index);
+                       if (event->family == AF_INET6)
+                               i = __mptcp_find_free_index(mptcp_local->loc6_bits, -1,
+                                                           mptcp_local->next_v6_index);
+
+                       if (i < 0) {
+                               mptcp_debug("%s no more space\n", __func__);
+                               goto duno;
+                       }
+
+                       /* It might have been a MOD-event. */
+                       event->code = MPTCP_EVENT_ADD;
+               } else {
+                       /* Let's check if anything changes */
+                       if (event->family == AF_INET && 
+                           event->low_prio == mptcp_local->locaddr4[i].low_prio)
+                               goto duno;
+
+                       if (event->family == AF_INET6 && 
+                           event->low_prio == mptcp_local->locaddr6[i].low_prio)
+                               goto duno;
+               }
+
+               old = mptcp_local;
+               mptcp_local = kmemdup(mptcp_local, sizeof(*mptcp_local),
+                                     GFP_ATOMIC);
+               if (!mptcp_local)
+                       goto duno;
+
+               if (event->family == AF_INET) {
+                       mptcp_local->locaddr4[i].addr.s_addr = event->addr.in.s_addr;
+                       mptcp_local->locaddr4[i].loc4_id = i + 1;
+                       mptcp_local->locaddr4[i].low_prio = event->low_prio;
+               } else {
+                       mptcp_local->locaddr6[i].addr = event->addr.in6;
+                       mptcp_local->locaddr6[i].loc6_id = i + MPTCP_MAX_ADDR;
+                       mptcp_local->locaddr6[i].low_prio = event->low_prio;
+               }
+
+               if (j < 0) {
+                       if (event->family == AF_INET) {
+                               mptcp_local->loc4_bits |= (1 << i);
+                               mptcp_local->next_v4_index = i + 1;
+                       } else {
+                               mptcp_local->loc6_bits |= (1 << i);
+                               mptcp_local->next_v6_index = i + 1;
+                       }
+               }
+
+               rcu_assign_pointer(fm_ns->local, mptcp_local);
+               kfree(old);
+       }
+       success = true;
+
+duno:
+       spin_unlock(&fm_ns->local_lock);
+       rcu_read_unlock_bh();
+
+       if (!success)
+               goto next_event;
+
+       /* Now we iterate over the MPTCP-sockets and apply the event. */
+       for (i = 0; i < MPTCP_HASH_SIZE; i++) {
+               struct hlist_nulls_node *node;
+               struct tcp_sock *meta_tp;
+
+               rcu_read_lock_bh();
+               hlist_nulls_for_each_entry_rcu(meta_tp, node, &tk_hashtable[i],
+                                              tk_table) {
+                       struct mptcp_cb *mpcb = meta_tp->mpcb;
+                       struct sock *meta_sk = (struct sock *)meta_tp, *sk;
+                       struct fullmesh_priv *fmp = (struct fullmesh_priv *)&mpcb->mptcp_pm[0];
+
+                       if (sock_net(meta_sk) != net)
+                               continue;
+
+                       if (unlikely(!atomic_inc_not_zero(&meta_sk->sk_refcnt)))
+                               continue;
+
+                       bh_lock_sock(meta_sk);
+
+                       if (!meta_tp->mpc || !is_meta_sk(meta_sk) ||
+                           mpcb->infinite_mapping_snd ||
+                           mpcb->infinite_mapping_rcv ||
+                           mpcb->send_infinite_mapping)
+                               goto next;
+
+                       /* May be that the pm has changed in-between */
+                       if (mpcb->pm_ops != &full_mesh)
+                               goto next;
+
+                       if (sock_owned_by_user(meta_sk)) {
+                               if (!test_and_set_bit(MPTCP_PATH_MANAGER,
+                                                     &meta_tp->tsq_flags))
+                                       sock_hold(meta_sk);
+
+                               goto next;
+                       }
+
+                       if (event->code == MPTCP_EVENT_ADD) {
+                               if (event->family == AF_INET)
+                                       fmp->add_addr++;
+#if IS_ENABLED(CONFIG_IPV6)
+                               if (event->family == AF_INET6)
+                                       fmp->add_addr++;
+#endif
+
+                               sk = mptcp_select_ack_sock(meta_sk, 0);
+                               if (sk)
+                                       tcp_send_ack(sk);
+
+                               full_mesh_create_subflows(meta_sk);
+                       }
+
+                       if (event->code == MPTCP_EVENT_DEL) {
+                               struct sock *sk, *tmpsk;
+                               struct mptcp_loc_addr *mptcp_local;
+                               bool found = false;
+
+                               mptcp_local = rcu_dereference_bh(fm_ns->local);
+
+                               /* Look for the socket and remove him */
+                               mptcp_for_each_sk_safe(mpcb, sk, tmpsk) {
+                                       if ((event->family == AF_INET6 &&
+                                            (sk->sk_family == AF_INET ||
+                                             mptcp_v6_is_v4_mapped(sk))) ||
+                                           (event->family == AF_INET &&
+                                            (sk->sk_family == AF_INET6 &&
+                                             !mptcp_v6_is_v4_mapped(sk))))
+                                               continue;
+
+                                       if (event->family == AF_INET &&
+                                           (sk->sk_family == AF_INET ||
+                                            mptcp_v6_is_v4_mapped(sk)) &&
+                                            inet_sk(sk)->inet_saddr != event->addr.in.s_addr)
+                                               continue;
+
+                                       if (event->family == AF_INET6 &&
+                                           sk->sk_family == AF_INET6 &&
+                                           !ipv6_addr_equal(&inet6_sk(sk)->saddr, &event->addr.in6))
+                                               continue;
+
+                                       /* Reinject, so that pf = 1 and so we
+                                        * won't select this one as the
+                                        * ack-sock.
+                                        */
+                                       mptcp_reinject_data(sk, 0);
+
+                                       /* A master is special, it has
+                                        * address-id 0
+                                        */
+                                       if (!tcp_sk(sk)->mptcp->loc_id)
+                                               update_remove_addrs(0, meta_sk, mptcp_local);
+                                       else if (tcp_sk(sk)->mptcp->loc_id != id)
+                                               update_remove_addrs(tcp_sk(sk)->mptcp->loc_id, meta_sk, mptcp_local);
+
+                                       mptcp_sub_force_close(sk);
+                                       found = true;
+                               }
+
+                               if (!found)
+                                       goto next;
+
+                               /* The id may have been given by the event,
+                                * matching on a local address. And it may not
+                                * have matched on one of the above sockets,
+                                * because the client never created a subflow.
+                                * So, we have to finally remove it here.
+                                */
+                               if (id > 0)
+                                       update_remove_addrs(id, meta_sk, mptcp_local);
+                       }
+
+                       if (event->code == MPTCP_EVENT_MOD) {
+                               struct sock *sk;
+
+                               mptcp_for_each_sk(mpcb, sk) {
+                                       struct tcp_sock *tp = tcp_sk(sk);
+                                       if (event->family == AF_INET &&
+                                           (sk->sk_family == AF_INET ||
+                                            mptcp_v6_is_v4_mapped(sk)) &&
+                                            inet_sk(sk)->inet_saddr == event->addr.in.s_addr) {
+                                               if (event->low_prio != tp->mptcp->low_prio) {
+                                                       tp->mptcp->send_mp_prio = 1;
+                                                       tp->mptcp->low_prio = event->low_prio;
+
+                                                       tcp_send_ack(sk);
+                                               }
+                                       }
+
+                                       if (event->family == AF_INET6 &&
+                                           sk->sk_family == AF_INET6 &&
+                                           !ipv6_addr_equal(&inet6_sk(sk)->saddr, &event->addr.in6)) {
+                                               if (event->low_prio != tp->mptcp->low_prio) {
+                                                       tp->mptcp->send_mp_prio = 1;
+                                                       tp->mptcp->low_prio = event->low_prio;
+
+                                                       tcp_send_ack(sk);
+                                               }
+                                       }
+                               }
+                       }
+next:
+                       bh_unlock_sock(meta_sk);
+                       sock_put(meta_sk);
+               }
+               rcu_read_unlock_bh();
+       }
+       goto next_event;
+}
+
+static struct mptcp_addr_event *lookup_similar_event(struct net *net,
+                                                    struct mptcp_addr_event *event)
+{
+       struct mptcp_addr_event *eventq;
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(net);
+
+       list_for_each_entry(eventq, &fm_ns->events, list) {
+               if (eventq->family != event->family)
+                       continue;
+               if (event->family == AF_INET) {
+                       if (eventq->addr.in.s_addr == event->addr.in.s_addr)
+                               return eventq;
+               } else {
+                       if (ipv6_addr_equal(&eventq->addr.in6, &event->addr.in6))
+                               return eventq;
+               }
+       }
+       return NULL;
+}
+
+/* We already hold the net-namespace MPTCP-lock */
+static void add_pm_event(struct net *net, struct mptcp_addr_event *event)
+{
+       struct mptcp_addr_event *eventq = lookup_similar_event(net, event);
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(net);
+
+       if (eventq) {
+               switch (event->code) {
+               case MPTCP_EVENT_DEL:
+                       list_del(&eventq->list);
+                       kfree(eventq);
+                       break;
+               case MPTCP_EVENT_ADD:
+                       eventq->low_prio = event->low_prio;
+                       eventq->code = MPTCP_EVENT_ADD;
+                       return;
+               case MPTCP_EVENT_MOD:
+                       eventq->low_prio = event->low_prio;
+                       return;
+               }
+       }
+
+       /* OK, we have to add the new address to the wait queue */
+       eventq = kmemdup(event, sizeof(struct mptcp_addr_event), GFP_ATOMIC);
+       if (!eventq)
+               return;
+
+       list_add_tail(&eventq->list, &fm_ns->events);
+
+       /* Create work-queue */
+       if (!delayed_work_pending(&fm_ns->address_worker))
+               queue_delayed_work(mptcp_wq, &fm_ns->address_worker,
+                                  msecs_to_jiffies(500));
+}
+
+static void addr4_event_handler(struct in_ifaddr *ifa, unsigned long event,
+                               struct net *net)
+{
+       struct net_device *netdev = ifa->ifa_dev->dev;
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(net);
+       struct mptcp_addr_event mpevent;
+
+       if (ifa->ifa_scope > RT_SCOPE_LINK ||
+           ipv4_is_loopback(ifa->ifa_local))
+               return;
+
+       spin_lock_bh(&fm_ns->local_lock);
+
+       mpevent.family = AF_INET;
+       mpevent.addr.in.s_addr = ifa->ifa_local;
+       mpevent.low_prio = (netdev->flags & IFF_MPBACKUP) ? 1 : 0;
+
+       if (event == NETDEV_DOWN || !netif_running(netdev) ||
+           (netdev->flags & IFF_NOMULTIPATH))
+               mpevent.code = MPTCP_EVENT_DEL;
+       else if (event == NETDEV_UP)
+               mpevent.code = MPTCP_EVENT_ADD;
+       else if (event == NETDEV_CHANGE)
+               mpevent.code = MPTCP_EVENT_MOD;
+
+       add_pm_event(net, &mpevent);
+
+       spin_unlock_bh(&fm_ns->local_lock);
+       return;
+}
+
+/* React on IPv4-addr add/rem-events */
+static int mptcp_pm_inetaddr_event(struct notifier_block *this,
+                                  unsigned long event, void *ptr)
+{
+       struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
+       struct net *net = dev_net(ifa->ifa_dev->dev);
+
+       addr4_event_handler(ifa, event, net);
+
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block mptcp_pm_inetaddr_notifier = {
+               .notifier_call = mptcp_pm_inetaddr_event,
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+
+/* IPV6-related address/interface watchers */
+struct mptcp_dad_data {
+       struct timer_list timer;
+       struct inet6_ifaddr *ifa;
+};
+
+static void dad_callback(unsigned long arg);
+static int inet6_addr_event(struct notifier_block *this,
+                                    unsigned long event, void *ptr);
+
+static int ipv6_is_in_dad_state(struct inet6_ifaddr *ifa)
+{
+       return ((ifa->flags & IFA_F_TENTATIVE) &&
+               ifa->state == INET6_IFADDR_STATE_DAD);
+}
+
+static void dad_init_timer(struct mptcp_dad_data *data,
+                                struct inet6_ifaddr *ifa)
+{
+       data->ifa = ifa;
+       data->timer.data = (unsigned long)data;
+       data->timer.function = dad_callback;
+       if (ifa->idev->cnf.rtr_solicit_delay)
+               data->timer.expires = jiffies + ifa->idev->cnf.rtr_solicit_delay;
+       else
+               data->timer.expires = jiffies + (HZ/10);
+}
+
+static void dad_callback(unsigned long arg)
+{
+       struct mptcp_dad_data *data = (struct mptcp_dad_data *)arg;
+
+       if (ipv6_is_in_dad_state(data->ifa)) {
+               dad_init_timer(data, data->ifa);
+               add_timer(&data->timer);
+       } else {
+               inet6_addr_event(NULL, NETDEV_UP, data->ifa);
+               in6_ifa_put(data->ifa);
+               kfree(data);
+       }
+}
+
+static inline void dad_setup_timer(struct inet6_ifaddr *ifa)
+{
+       struct mptcp_dad_data *data;
+
+       data = kmalloc(sizeof(*data), GFP_ATOMIC);
+
+       if (!data)
+               return;
+
+       init_timer(&data->timer);
+       dad_init_timer(data, ifa);
+       add_timer(&data->timer);
+       in6_ifa_hold(ifa);
+}
+
+static void addr6_event_handler(struct inet6_ifaddr *ifa, unsigned long event,
+                               struct net *net)
+{
+       struct net_device *netdev = ifa->idev->dev;
+       int addr_type = ipv6_addr_type(&ifa->addr);
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(net);
+       struct mptcp_addr_event mpevent;
+
+       if (ifa->scope > RT_SCOPE_LINK ||
+           addr_type == IPV6_ADDR_ANY ||
+           (addr_type & IPV6_ADDR_LOOPBACK) ||
+           (addr_type & IPV6_ADDR_LINKLOCAL))
+               return;
+
+       spin_lock_bh(&fm_ns->local_lock);
+
+       mpevent.family = AF_INET6;
+       mpevent.addr.in6 = ifa->addr;
+       mpevent.low_prio = (netdev->flags & IFF_MPBACKUP) ? 1 : 0;
+
+       if (event == NETDEV_DOWN ||!netif_running(netdev) ||
+           (netdev->flags & IFF_NOMULTIPATH))
+               mpevent.code = MPTCP_EVENT_DEL;
+       else if (event == NETDEV_UP)
+               mpevent.code = MPTCP_EVENT_ADD;
+       else if (event == NETDEV_CHANGE)
+               mpevent.code = MPTCP_EVENT_MOD;
+
+       add_pm_event(net, &mpevent);
+
+       spin_unlock_bh(&fm_ns->local_lock);
+       return;
+}
+
+/* React on IPv6-addr add/rem-events */
+static int inet6_addr_event(struct notifier_block *this, unsigned long event,
+                           void *ptr)
+{
+       struct inet6_ifaddr *ifa6 = (struct inet6_ifaddr *)ptr;
+       struct net *net = dev_net(ifa6->idev->dev);
+
+       if (ipv6_is_in_dad_state(ifa6))
+               dad_setup_timer(ifa6);
+       else
+               addr6_event_handler(ifa6, event, net);
+
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block inet6_addr_notifier = {
+               .notifier_call = inet6_addr_event,
+};
+
+#endif
+
+/* React on ifup/down-events */
+static int netdev_event(struct notifier_block *this, unsigned long event,
+                       void *ptr)
+{
+       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+       struct in_device *in_dev;
+#if IS_ENABLED(CONFIG_IPV6)
+       struct inet6_dev *in6_dev;
+#endif
+
+       if (!(event == NETDEV_UP || event == NETDEV_DOWN ||
+             event == NETDEV_CHANGE))
+               return NOTIFY_DONE;
+
+       rcu_read_lock();
+       in_dev = __in_dev_get_rtnl(dev);
+
+       if (in_dev) {
+               for_ifa(in_dev) {
+                       mptcp_pm_inetaddr_event(NULL, event, ifa);
+               } endfor_ifa(in_dev);
+       }
+
+#if IS_ENABLED(CONFIG_IPV6)
+       in6_dev = __in6_dev_get(dev);
+
+       if (in6_dev) {
+               struct inet6_ifaddr *ifa6;
+               list_for_each_entry(ifa6, &in6_dev->addr_list, if_list)
+                       inet6_addr_event(NULL, event, ifa6);
+       }
+#endif
+
+       rcu_read_unlock();
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block mptcp_pm_netdev_notifier = {
+               .notifier_call = netdev_event,
+};
+
+static void full_mesh_new_session(struct sock *meta_sk, int index)
+{
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct fullmesh_priv *fmp = (struct fullmesh_priv *)&mpcb->mptcp_pm[0];
+       struct net *net = sock_net(meta_sk);
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(net);
+       struct sock *sk;
+       int i;
+
+       if (index == -1) {
+               mptcp_fallback_default(mpcb);
+               return;
+       }
+
+       /* Initialize workqueue-struct */
+       INIT_WORK(&fmp->subflow_work, create_subflow_worker);
+       INIT_DELAYED_WORK(&fmp->subflow_retry_work, retry_subflow_worker);
+       fmp->mpcb = mpcb;
+
+       sk = mptcp_select_ack_sock(meta_sk, 0);
+
+       rcu_read_lock();
+       mptcp_local = rcu_dereference(fm_ns->local);
+
+       /* Look for the address among the local addresses */
+       mptcp_for_each_bit_set(mptcp_local->loc4_bits, i) {
+               __be32 ifa_address = mptcp_local->locaddr4[i].addr.s_addr;
+
+               /* We do not need to announce the initial subflow's address again */
+               if ((meta_sk->sk_family == AF_INET ||
+                    mptcp_v6_is_v4_mapped(meta_sk)) &&
+                   inet_sk(meta_sk)->inet_saddr == ifa_address)
+                       continue;
+
+               fmp->add_addr++;
+
+               if (sk)
+                       tcp_send_ack(sk);
+       }
+
+#if IS_ENABLED(CONFIG_IPV6)
+       mptcp_for_each_bit_set(mptcp_local->loc6_bits, i) {
+               struct in6_addr *ifa6 = &mptcp_local->locaddr6[i].addr;
+
+               /* We do not need to announce the initial subflow's address again */
+               if (meta_sk->sk_family == AF_INET6 &&
+                   ipv6_addr_equal(&inet6_sk(meta_sk)->saddr, ifa6))
+                       continue;
+
+               fmp->add_addr++;
+
+               if (sk)
+                       tcp_send_ack(sk);
+       }
+#endif
+
+       rcu_read_unlock();
+
+       if (meta_sk->sk_family == AF_INET || mptcp_v6_is_v4_mapped(meta_sk))
+               fmp->announced_addrs_v4 |= (1 << index);
+       else
+               fmp->announced_addrs_v6 |= (1 << index);
+}
+
+static void full_mesh_create_subflows(struct sock *meta_sk)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct fullmesh_priv *pm_priv = (struct fullmesh_priv *)&mpcb->mptcp_pm[0];
+
+       if (mpcb->infinite_mapping_snd || mpcb->infinite_mapping_rcv ||
+           mpcb->send_infinite_mapping ||
+           mpcb->server_side || sock_flag(meta_sk, SOCK_DEAD))
+               return;
+
+       /* The master may not yet be fully established (address added through
+        * mptcp_update_metasocket). Then, we should not attempt to create new
+        * subflows.
+        */
+       if (mpcb->master_sk &&
+           !tcp_sk(mpcb->master_sk)->mptcp->fully_established)
+               return;
+
+       if (!work_pending(&pm_priv->subflow_work)) {
+               sock_hold(meta_sk);
+               queue_work(mptcp_wq, &pm_priv->subflow_work);
+       }
+}
+
+/* Called upon release_sock, if the socket was owned by the user during
+ * a path-management event.
+ */
+static void full_mesh_release_sock(struct sock *meta_sk)
+{
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct fullmesh_priv *fmp = (struct fullmesh_priv *)&mpcb->mptcp_pm[0];
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(sock_net(meta_sk));
+       struct sock *sk, *tmpsk;
+       int i;
+
+       rcu_read_lock();
+       mptcp_local = rcu_dereference(fm_ns->local);
+
+       /* First, detect modifications or additions */
+       mptcp_for_each_bit_set(mptcp_local->loc4_bits, i) {
+               struct in_addr ifa = mptcp_local->locaddr4[i].addr;
+               bool found = false;
+
+               mptcp_for_each_sk(mpcb, sk) {
+                       struct tcp_sock *tp = tcp_sk(sk);
+
+                       if (sk->sk_family == AF_INET6 &&
+                           !mptcp_v6_is_v4_mapped(sk))
+                               continue;
+
+                       if (inet_sk(sk)->inet_saddr != ifa.s_addr)
+                               continue;
+
+                       found = true;
+
+                       if (mptcp_local->locaddr4[i].low_prio != tp->mptcp->low_prio) {
+                               tp->mptcp->send_mp_prio = 1;
+                               tp->mptcp->low_prio = mptcp_local->locaddr4[i].low_prio;
+
+                               tcp_send_ack(sk);
+                       }
+               }
+
+               if (!found) {
+                       fmp->add_addr++;
+
+                       sk = mptcp_select_ack_sock(meta_sk, 0);
+                       if (sk)
+                               tcp_send_ack(sk);
+                       full_mesh_create_subflows(meta_sk);
+               }
+       }
+
+#if IS_ENABLED(CONFIG_IPV6)
+       mptcp_for_each_bit_set(mptcp_local->loc6_bits, i) {
+               struct in6_addr ifa = mptcp_local->locaddr6[i].addr;
+               bool found = false;
+
+               mptcp_for_each_sk(mpcb, sk) {
+                       struct tcp_sock *tp = tcp_sk(sk);
+
+                       if (sk->sk_family == AF_INET ||
+                           mptcp_v6_is_v4_mapped(sk))
+                               continue;
+
+                       if (!ipv6_addr_equal(&inet6_sk(sk)->saddr, &ifa))
+                               continue;
+
+                       found = true;
+
+                       if (mptcp_local->locaddr6[i].low_prio != tp->mptcp->low_prio) {
+                               tp->mptcp->send_mp_prio = 1;
+                               tp->mptcp->low_prio = mptcp_local->locaddr6[i].low_prio;
+
+                               tcp_send_ack(sk);
+                       }
+               }
+
+               if (!found) {
+                       fmp->add_addr++;
+
+                       sk = mptcp_select_ack_sock(meta_sk, 0);
+                       if (sk)
+                               tcp_send_ack(sk);
+                       full_mesh_create_subflows(meta_sk);
+               }
+       }
+#endif
+
+       /* Now, detect address-removals */
+       mptcp_for_each_sk_safe(mpcb, sk, tmpsk) {
+               bool shall_remove = true;
+
+               if (sk->sk_family == AF_INET || mptcp_v6_is_v4_mapped(sk)) {
+                       mptcp_for_each_bit_set(mptcp_local->loc4_bits, i) {
+                               if (inet_sk(sk)->inet_saddr == mptcp_local->locaddr4[i].addr.s_addr) {
+                                       shall_remove = false;
+                                       break;
+                               }
+                       }
+               } else {
+                       mptcp_for_each_bit_set(mptcp_local->loc6_bits, i) {
+                               if (ipv6_addr_equal(&inet6_sk(sk)->saddr, &mptcp_local->locaddr6[i].addr)) {
+                                       shall_remove = false;
+                                       break;
+                               }
+                       }
+               }
+
+               if (shall_remove) {
+                       /* Reinject, so that pf = 1 and so we
+                        * won't select this one as the
+                        * ack-sock.
+                        */
+                       mptcp_reinject_data(sk, 0);
+
+                       update_remove_addrs(tcp_sk(sk)->mptcp->loc_id, meta_sk,
+                                           mptcp_local);
+
+                       if (mpcb->master_sk == sk)
+                               update_remove_addrs(0, meta_sk, mptcp_local);
+
+                       mptcp_sub_force_close(sk);
+               }
+       }
+       rcu_read_unlock();
+}
+
+static int full_mesh_get_local_index(sa_family_t family, union inet_addr *addr,
+                                    struct net *net)
+{
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(net);
+       int index;
+
+       /* Handle the backup-flows */
+       rcu_read_lock();
+       mptcp_local = rcu_dereference(fm_ns->local);
+
+       index = mptcp_find_address(mptcp_local, family, addr);
+
+       rcu_read_unlock();
+
+       return index;
+}
+
+static int full_mesh_get_local_id(sa_family_t family, union inet_addr *addr,
+                                 struct net *net)
+{
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(net);
+       int index, id = -1;
+
+       /* Handle the backup-flows */
+       rcu_read_lock();
+       mptcp_local = rcu_dereference(fm_ns->local);
+
+       index = mptcp_find_address(mptcp_local, family, addr);
+
+       if (index != -1) {
+               if (family == AF_INET)
+                       id = mptcp_local->locaddr4[index].loc4_id;
+               else
+                       id = mptcp_local->locaddr6[index].loc6_id;
+       }
+
+
+       rcu_read_unlock();
+
+       return id;
+}
+
+static void full_mesh_addr_signal(struct sock *sk, unsigned *size,
+                                 struct tcp_out_options *opts,
+                                 struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct mptcp_cb *mpcb = tp->mpcb;
+       struct fullmesh_priv *fmp = (struct fullmesh_priv *)&mpcb->mptcp_pm[0];
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_fm_ns *fm_ns = fm_get_ns(sock_net(sk));
+       int remove_addr_len;
+       u8 unannouncedv4, unannouncedv6;
+
+       if (likely(!fmp->add_addr))
+               goto remove_addr;
+
+       rcu_read_lock();
+       mptcp_local = rcu_dereference(fm_ns->local);
+
+       /* IPv4 */
+       unannouncedv4 = (~fmp->announced_addrs_v4) & mptcp_local->loc4_bits;
+       if (unannouncedv4 &&
+           MAX_TCP_OPTION_SPACE - *size >= MPTCP_SUB_LEN_ADD_ADDR4_ALIGN) {
+               int ind = mptcp_find_free_index(~unannouncedv4);
+
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_ADD_ADDR;
+               opts->add_addr4.addr_id = mptcp_local->locaddr4[ind].loc4_id;
+               opts->add_addr4.addr = mptcp_local->locaddr4[ind].addr;
+               opts->add_addr_v4 = 1;
+
+               if (skb) {
+                       fmp->announced_addrs_v4 |= (1 << ind);
+                       fmp->add_addr--;
+               }
+               *size += MPTCP_SUB_LEN_ADD_ADDR4_ALIGN;
+       }
+
+       /* IPv6 */
+       unannouncedv6 = (~fmp->announced_addrs_v6) & mptcp_local->loc6_bits;
+       if (unannouncedv6 &&
+           MAX_TCP_OPTION_SPACE - *size >= MPTCP_SUB_LEN_ADD_ADDR6_ALIGN) {
+               int ind = mptcp_find_free_index(~unannouncedv6);
+
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_ADD_ADDR;
+               opts->add_addr6.addr_id = mptcp_local->locaddr6[ind].loc6_id;
+               opts->add_addr6.addr = mptcp_local->locaddr6[ind].addr;
+               opts->add_addr_v6 = 1;
+
+               if (skb) {
+                       fmp->announced_addrs_v6 |= (1 << ind);
+                       fmp->add_addr--;
+               }
+               *size += MPTCP_SUB_LEN_ADD_ADDR6_ALIGN;
+       }
+
+       rcu_read_unlock();
+
+       if (!unannouncedv4 && !unannouncedv6 && skb) {
+               fmp->add_addr--;
+       }
+
+remove_addr:
+       if (likely(!fmp->remove_addrs))
+               return;
+
+       remove_addr_len = mptcp_sub_len_remove_addr_align(fmp->remove_addrs);
+       if (MAX_TCP_OPTION_SPACE - *size < remove_addr_len)
+               return;
+
+       opts->options |= OPTION_MPTCP;
+       opts->mptcp_options |= OPTION_REMOVE_ADDR;
+       opts->remove_addrs = fmp->remove_addrs;
+       *size += remove_addr_len;
+       if (skb)
+               fmp->remove_addrs = 0;
+}
+
+static int mptcp_fm_init_net(struct net *net)
+{
+       struct mptcp_loc_addr *mptcp_local;
+       struct mptcp_fm_ns *fm_ns;
+
+       fm_ns = kzalloc(sizeof(*fm_ns), GFP_KERNEL);
+       if (!fm_ns)
+               return -ENOBUFS;
+
+       mptcp_local = kzalloc(sizeof(*mptcp_local), GFP_KERNEL);
+       if (!mptcp_local) {
+               kfree(fm_ns);
+               return -ENOBUFS;
+       }
+
+       mptcp_local->next_v4_index = 1;
+
+       rcu_assign_pointer(fm_ns->local, mptcp_local);
+       INIT_DELAYED_WORK(&fm_ns->address_worker, mptcp_address_worker);
+       INIT_LIST_HEAD(&fm_ns->events);
+       spin_lock_init(&fm_ns->local_lock);
+       fm_ns->net = net;
+       net->mptcp.path_managers[MPTCP_PM_FULLMESH] = fm_ns;
+
+       return 0;
+}
+
+static void mptcp_fm_exit_net(struct net *net)
+{
+       struct mptcp_addr_event *eventq, *tmp;
+       struct mptcp_fm_ns *fm_ns;
+       struct mptcp_loc_addr *mptcp_local;
+
+       fm_ns = fm_get_ns(net);
+       cancel_delayed_work_sync(&fm_ns->address_worker);
+
+       rcu_read_lock_bh();
+
+       mptcp_local = rcu_dereference_bh(fm_ns->local);
+       kfree(mptcp_local);
+
+       spin_lock(&fm_ns->local_lock);
+       list_for_each_entry_safe(eventq, tmp, &fm_ns->events, list) {
+               list_del(&eventq->list);
+               kfree(eventq);
+       }
+       spin_unlock(&fm_ns->local_lock);
+
+       rcu_read_unlock_bh();
+
+       kfree(fm_ns);
+}
+
+static struct pernet_operations full_mesh_net_ops = {
+       .init = mptcp_fm_init_net,
+       .exit = mptcp_fm_exit_net,
+};
+
+static struct mptcp_pm_ops full_mesh __read_mostly = {
+       .new_session = full_mesh_new_session,
+       .release_sock = full_mesh_release_sock,
+       .fully_established = full_mesh_create_subflows,
+       .new_remote_address = full_mesh_create_subflows,
+       .get_local_index = full_mesh_get_local_index,
+       .get_local_id = full_mesh_get_local_id,
+       .addr_signal = full_mesh_addr_signal,
+       .name = "fullmesh",
+       .owner = THIS_MODULE,
+};
+
+/* General initialization of MPTCP_PM */
+static int __init full_mesh_register(void)
+{
+       int ret;
+
+       BUILD_BUG_ON(sizeof(struct fullmesh_priv) > MPTCP_PM_SIZE);
+
+       ret = register_pernet_subsys(&full_mesh_net_ops);
+       if (ret)
+               goto out;
+
+       ret = register_inetaddr_notifier(&mptcp_pm_inetaddr_notifier);
+       if (ret)
+               goto err_reg_inetaddr;
+       ret = register_netdevice_notifier(&mptcp_pm_netdev_notifier);
+       if (ret)
+               goto err_reg_netdev;
+
+#if IS_ENABLED(CONFIG_IPV6)
+       ret = register_inet6addr_notifier(&inet6_addr_notifier);
+       if (ret)
+               goto err_reg_inet6addr;
+#endif
+
+       ret = mptcp_register_path_manager(&full_mesh);
+       if (ret)
+               goto err_reg_pm;
+
+out:
+       return ret;
+
+
+err_reg_pm:
+#if IS_ENABLED(CONFIG_IPV6)
+       unregister_inet6addr_notifier(&inet6_addr_notifier);
+err_reg_inet6addr:
+#endif
+       unregister_netdevice_notifier(&mptcp_pm_netdev_notifier);
+err_reg_netdev:
+       unregister_inetaddr_notifier(&mptcp_pm_inetaddr_notifier);
+err_reg_inetaddr:
+       unregister_pernet_subsys(&full_mesh_net_ops);
+       goto out;
+}
+
+static void full_mesh_unregister(void)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+       unregister_inet6addr_notifier(&inet6_addr_notifier);
+#endif
+       unregister_netdevice_notifier(&mptcp_pm_netdev_notifier);
+       unregister_inetaddr_notifier(&mptcp_pm_inetaddr_notifier);
+       unregister_pernet_subsys(&full_mesh_net_ops);
+       mptcp_unregister_path_manager(&full_mesh);
+}
+
+module_init(full_mesh_register);
+module_exit(full_mesh_unregister);
+
+MODULE_AUTHOR("Christoph Paasch");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Full-Mesh MPTCP");
+MODULE_VERSION("0.88");
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_input.c linux-3.14.45/net/mptcp/mptcp_input.c
--- linux-3.14.45.orig/net/mptcp/mptcp_input.c  1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_input.c       2015-06-24 14:15:48.895862487 +0200
@@ -0,0 +1,2254 @@
+/*
+ *     MPTCP implementation - Sending side
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <asm/unaligned.h>
+
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+#include <net/mptcp_v6.h>
+
+#include <linux/kconfig.h>
+
+/* is seq1 < seq2 ? */
+static inline int before64(const u64 seq1, const u64 seq2)
+{
+       return (s64)(seq1 - seq2) < 0;
+}
+
+/* is seq1 > seq2 ? */
+#define after64(seq1, seq2)    before64(seq2, seq1)
+
+static inline void mptcp_become_fully_estab(struct sock *sk)
+{
+       tcp_sk(sk)->mptcp->fully_established = 1;
+
+       if (is_master_tp(tcp_sk(sk)) &&
+           tcp_sk(sk)->mpcb->pm_ops->fully_established)
+               tcp_sk(sk)->mpcb->pm_ops->fully_established(mptcp_meta_sk(sk));
+}
+
+/* Similar to tcp_tso_acked without any memory accounting */
+static inline int mptcp_tso_acked_reinject(struct sock *sk, struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       u32 packets_acked, len;
+
+       BUG_ON(!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una));
+
+       packets_acked = tcp_skb_pcount(skb);
+
+       if (skb_unclone(skb, GFP_ATOMIC))
+               return 0;
+
+       len = tp->snd_una - TCP_SKB_CB(skb)->seq;
+       __pskb_trim_head(skb, len);
+
+       TCP_SKB_CB(skb)->seq += len;
+       skb->ip_summed = CHECKSUM_PARTIAL;
+       skb->truesize        -= len;
+
+       /* Any change of skb->len requires recalculation of tso factor. */
+       if (tcp_skb_pcount(skb) > 1)
+               tcp_set_skb_tso_segs(sk, skb, tcp_skb_mss(skb));
+       packets_acked -= tcp_skb_pcount(skb);
+
+       if (packets_acked) {
+               BUG_ON(tcp_skb_pcount(skb) == 0);
+               BUG_ON(!before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq));
+       }
+
+       return packets_acked;
+}
+
+/**
+ * Cleans the meta-socket retransmission queue and the reinject-queue.
+ * @sk must be the metasocket.
+ */
+static void mptcp_clean_rtx_queue(struct sock *meta_sk, u32 prior_snd_una)
+{
+       struct sk_buff *skb, *tmp;
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       bool acked = false;
+       u32 acked_pcount;
+
+       while ((skb = tcp_write_queue_head(meta_sk)) &&
+              skb != tcp_send_head(meta_sk)) {
+               bool fully_acked = true;
+
+               if (before(meta_tp->snd_una, TCP_SKB_CB(skb)->end_seq)) {
+                       if (tcp_skb_pcount(skb) == 1 ||
+                           !after(meta_tp->snd_una, TCP_SKB_CB(skb)->seq))
+                               break;
+
+                       acked_pcount = tcp_tso_acked(meta_sk, skb);
+                       if (!acked_pcount)
+                               break;
+
+                       fully_acked = false;
+               } else {
+                       acked_pcount = tcp_skb_pcount(skb);
+               }
+
+               acked = true;
+               meta_tp->packets_out -= acked_pcount;
+               meta_tp->retrans_stamp = 0;
+
+               if (!fully_acked)
+                       break;
+
+               tcp_unlink_write_queue(skb, meta_sk);
+
+               if (mptcp_is_data_fin(skb)) {
+                       struct sock *sk_it;
+
+                       /* DATA_FIN has been acknowledged - now we can close
+                        * the subflows
+                        */
+                       mptcp_for_each_sk(mpcb, sk_it) {
+                               unsigned long delay = 0;
+
+                               /* If we are the passive closer, don't trigger
+                                * subflow-fin until the subflow has been finned
+                                * by the peer - thus we add a delay.
+                                */
+                               if (mpcb->passive_close &&
+                                   sk_it->sk_state == TCP_ESTABLISHED)
+                                       delay = inet_csk(sk_it)->icsk_rto << 3;
+
+                               mptcp_sub_close(sk_it, delay);
+                       }
+               }
+               sk_wmem_free_skb(meta_sk, skb);
+       }
+       /* Remove acknowledged data from the reinject queue */
+       skb_queue_walk_safe(&mpcb->reinject_queue, skb, tmp) {
+               if (before(meta_tp->snd_una, TCP_SKB_CB(skb)->end_seq)) {
+                       if (tcp_skb_pcount(skb) == 1 ||
+                           !after(meta_tp->snd_una, TCP_SKB_CB(skb)->seq))
+                               break;
+
+                       mptcp_tso_acked_reinject(meta_sk, skb);
+                       break;
+               }
+
+               __skb_unlink(skb, &mpcb->reinject_queue);
+               __kfree_skb(skb);
+       }
+
+       if (likely(between(meta_tp->snd_up, prior_snd_una, meta_tp->snd_una)))
+               meta_tp->snd_up = meta_tp->snd_una;
+
+       if (acked) {
+               tcp_rearm_rto(meta_sk);
+               /* Normally this is done in tcp_try_undo_loss - but MPTCP
+                * does not call this function.
+                */
+               inet_csk(meta_sk)->icsk_retransmits = 0;
+       }
+}
+
+/* Inspired by tcp_rcv_state_process */
+static int mptcp_rcv_state_process(struct sock *meta_sk, struct sock *sk,
+                                  const struct sk_buff *skb, u32 data_seq,
+                                  u16 data_len)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk), *tp = tcp_sk(sk);
+       struct tcphdr *th = tcp_hdr(skb);
+
+       /* State-machine handling if FIN has been enqueued and he has
+        * been acked (snd_una == write_seq) - it's important that this
+        * here is after sk_wmem_free_skb because otherwise
+        * sk_forward_alloc is wrong upon inet_csk_destroy_sock()
+        */
+       switch (meta_sk->sk_state) {
+       case TCP_FIN_WAIT1:
+               if (meta_tp->snd_una == meta_tp->write_seq) {
+                       struct dst_entry *dst = __sk_dst_get(meta_sk);
+
+                       tcp_set_state(meta_sk, TCP_FIN_WAIT2);
+                       meta_sk->sk_shutdown |= SEND_SHUTDOWN;
+
+                       dst = __sk_dst_get(sk);
+                       if (dst)
+                               dst_confirm(dst);
+
+                       if (!sock_flag(meta_sk, SOCK_DEAD)) {
+                               /* Wake up lingering close() */
+                               meta_sk->sk_state_change(meta_sk);
+                       } else {
+                               int tmo;
+
+                               if (meta_tp->linger2 < 0 ||
+                                   (data_len &&
+                                    after(data_seq + data_len - (mptcp_is_data_fin2(skb, tp) ? 1 : 0),
+                                          meta_tp->rcv_nxt))) {
+                                       mptcp_send_active_reset(meta_sk, GFP_ATOMIC);
+                                       tcp_done(meta_sk);
+                                       NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_TCPABORTONDATA);
+                                       return 1;
+                               }
+
+                               tmo = tcp_fin_time(meta_sk);
+                               if (tmo > TCP_TIMEWAIT_LEN) {
+                                       inet_csk_reset_keepalive_timer(meta_sk, tmo - TCP_TIMEWAIT_LEN);
+                               } else if (mptcp_is_data_fin2(skb, tp) ||
+                                          sock_owned_by_user(meta_sk)) {
+                                       /* Bad case. We could lose such FIN otherwise.
+                                        * It is not a big problem, but it looks confusing
+                                        * and not so rare event. We still can lose it now,
+                                        * if it spins in bh_lock_sock(), but it is really
+                                        * marginal case.
+                                        */
+                                       inet_csk_reset_keepalive_timer(meta_sk, tmo);
+                               } else {
+                                       tcp_time_wait(meta_sk, TCP_FIN_WAIT2, tmo);
+                               }
+                       }
+               }
+               break;
+       case TCP_CLOSING:
+       case TCP_LAST_ACK:
+               if (meta_tp->snd_una == meta_tp->write_seq) {
+                       tcp_done(meta_sk);
+                       return 1;
+               }
+               break;
+       }
+
+       /* step 7: process the segment text */
+       switch (meta_sk->sk_state) {
+       case TCP_FIN_WAIT1:
+       case TCP_FIN_WAIT2:
+               /* RFC 793 says to queue data in these states,
+                * RFC 1122 says we MUST send a reset.
+                * BSD 4.4 also does reset.
+                */
+               if (meta_sk->sk_shutdown & RCV_SHUTDOWN) {
+                       if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq &&
+                           after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt) &&
+                           !mptcp_is_data_fin2(skb, tp)) {
+                               NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_TCPABORTONDATA);
+                               mptcp_send_active_reset(meta_sk, GFP_ATOMIC);
+                               tcp_reset(meta_sk);
+                               return 1;
+                       }
+               }
+               break;
+       }
+
+       return 0;
+}
+
+/**
+ * @return:
+ *  i) 1: Everything's fine.
+ *  ii) -1: A reset has been sent on the subflow - csum-failure
+ *  iii) 0: csum-failure but no reset sent, because it's the last subflow.
+ *      Last packet should not be destroyed by the caller because it has
+ *      been done here.
+ */
+static int mptcp_verif_dss_csum(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sk_buff *tmp, *tmp1, *last = NULL;
+       __wsum csum_tcp = 0; /* cumulative checksum of pld + mptcp-header */
+       int ans = 1, overflowed = 0, offset = 0, dss_csum_added = 0;
+       int iter = 0;
+
+       skb_queue_walk_safe(&sk->sk_receive_queue, tmp, tmp1) {
+               unsigned int csum_len;
+
+               if (before(tp->mptcp->map_subseq + tp->mptcp->map_data_len, TCP_SKB_CB(tmp)->end_seq))
+                       /* Mapping ends in the middle of the packet -
+                        * csum only these bytes
+                        */
+                       csum_len = tp->mptcp->map_subseq + tp->mptcp->map_data_len - TCP_SKB_CB(tmp)->seq;
+               else
+                       csum_len = tmp->len;
+
+               offset = 0;
+               if (overflowed) {
+                       char first_word[4];
+                       first_word[0] = 0;
+                       first_word[1] = 0;
+                       first_word[2] = 0;
+                       first_word[3] = *(tmp->data);
+                       csum_tcp = csum_partial(first_word, 4, csum_tcp);
+                       offset = 1;
+                       csum_len--;
+                       overflowed = 0;
+               }
+
+               csum_tcp = skb_checksum(tmp, offset, csum_len, csum_tcp);
+
+               /* Was it on an odd-length? Then we have to merge the next byte
+                * correctly (see above)
+                */
+               if (csum_len != (csum_len & (~1)))
+                       overflowed = 1;
+
+               if (mptcp_is_data_seq(tmp) && !dss_csum_added) {
+                       __be32 data_seq = htonl((u32)(tp->mptcp->map_data_seq >> 32));
+
+                       /* If a 64-bit dss is present, we increase the offset
+                        * by 4 bytes, as the high-order 64-bits will be added
+                        * in the final csum_partial-call.
+                        */
+                       u32 offset = skb_transport_offset(tmp) +
+                                    TCP_SKB_CB(tmp)->dss_off;
+                       if (TCP_SKB_CB(tmp)->mptcp_flags & MPTCPHDR_SEQ64_SET)
+                               offset += 4;
+
+                       csum_tcp = skb_checksum(tmp, offset,
+                                               MPTCP_SUB_LEN_SEQ_CSUM,
+                                               csum_tcp);
+
+                       csum_tcp = csum_partial(&data_seq,
+                                               sizeof(data_seq), csum_tcp);
+
+                       dss_csum_added = 1; /* Just do it once */
+               }
+               last = tmp;
+               iter++;
+
+               if (!skb_queue_is_last(&sk->sk_receive_queue, tmp) &&
+                   !before(TCP_SKB_CB(tmp1)->seq,
+                           tp->mptcp->map_subseq + tp->mptcp->map_data_len))
+                       break;
+       }
+
+       /* Now, checksum must be 0 */
+       if (unlikely(csum_fold(csum_tcp))) {
+               pr_err("%s csum is wrong: %#x data_seq %u dss_csum_added %d overflowed %d iterations %d\n",
+                           __func__, csum_fold(csum_tcp),
+                           TCP_SKB_CB(last)->seq, dss_csum_added, overflowed,
+                           iter);
+
+               tp->mptcp->send_mp_fail = 1;
+
+               /* map_data_seq is the data-seq number of the
+                * mapping we are currently checking
+                */
+               tp->mpcb->csum_cutoff_seq = tp->mptcp->map_data_seq;
+
+               if (tp->mpcb->cnt_subflows > 1) {
+                       mptcp_send_reset(sk);
+                       ans = -1;
+               } else {
+                       tp->mpcb->send_infinite_mapping = 1;
+
+                       /* Need to purge the rcv-queue as it's no more valid */
+                       while ((tmp = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+                               tp->copied_seq = TCP_SKB_CB(tmp)->end_seq;
+                               kfree_skb(tmp);
+                       }
+
+                       ans = 0;
+               }
+       }
+
+       return ans;
+}
+
+static inline void mptcp_prepare_skb(struct sk_buff *skb, struct sk_buff *next,
+                                    struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+       /* Adapt data-seq's to the packet itself. We kinda transform the
+        * dss-mapping to a per-packet granularity. This is necessary to
+        * correctly handle overlapping mappings coming from different
+        * subflows. Otherwise it would be a complete mess.
+        */
+       tcb->seq = ((u32)tp->mptcp->map_data_seq) + tcb->seq - tp->mptcp->map_subseq;
+       tcb->end_seq = tcb->seq + skb->len;
+
+       /* If cur is the last one in the rcv-queue (or the last one for this
+        * mapping), and data_fin is enqueued, the end_data_seq is +1.
+        */
+       if (skb_queue_is_last(&sk->sk_receive_queue, skb) ||
+           after(TCP_SKB_CB(next)->end_seq, tp->mptcp->map_subseq + tp->mptcp->map_data_len)) {
+               tcb->end_seq += tp->mptcp->map_data_fin;
+
+               /* We manually set the fin-flag if it is a data-fin. For easy
+                * processing in tcp_recvmsg.
+                */
+               if (mptcp_is_data_fin2(skb, tp))
+                       tcp_hdr(skb)->fin = 1;
+               else
+                       tcp_hdr(skb)->fin = 0;
+       } else {
+               /* We may have a subflow-fin with data but without data-fin */
+               tcp_hdr(skb)->fin = 0;
+       }
+}
+
+/**
+ * @return: 1 if the segment has been eaten and can be suppressed,
+ *          otherwise 0.
+ */
+static inline int mptcp_direct_copy(struct sk_buff *skb, struct sock *meta_sk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       int chunk = min_t(unsigned int, skb->len, meta_tp->ucopy.len);
+       int eaten = 0;
+
+       __set_current_state(TASK_RUNNING);
+
+       local_bh_enable();
+       if (!skb_copy_datagram_iovec(skb, 0, meta_tp->ucopy.iov, chunk)) {
+               meta_tp->ucopy.len -= chunk;
+               meta_tp->copied_seq += chunk;
+               eaten = (chunk == skb->len);
+               tcp_rcv_space_adjust(meta_sk);
+       }
+       local_bh_disable();
+       return eaten;
+}
+
+static inline void mptcp_reset_mapping(struct tcp_sock *tp)
+{
+       tp->mptcp->map_data_len = 0;
+       tp->mptcp->map_data_seq = 0;
+       tp->mptcp->map_subseq = 0;
+       tp->mptcp->map_data_fin = 0;
+       tp->mptcp->mapping_present = 0;
+}
+
+/* The DSS-mapping received on the sk only covers the second half of the skb
+ * (cut at seq). We trim the head from the skb.
+ * Data will be freed upon kfree().
+ *
+ * Inspired by tcp_trim_head().
+ */
+static void mptcp_skb_trim_head(struct sk_buff *skb, struct sock *sk, u32 seq)
+{
+       int len = seq - TCP_SKB_CB(skb)->seq;
+       u32 new_seq = TCP_SKB_CB(skb)->seq + len;
+
+       if (len < skb_headlen(skb))
+               __skb_pull(skb, len);
+       else
+               __pskb_trim_head(skb, len - skb_headlen(skb));
+
+       TCP_SKB_CB(skb)->seq = new_seq;
+
+       skb->truesize -= len;
+       atomic_sub(len, &sk->sk_rmem_alloc);
+       sk_mem_uncharge(sk, len);
+}
+
+/* The DSS-mapping received on the sk only covers the first half of the skb
+ * (cut at seq). We create a second skb (@return), and queue it in the rcv-queue
+ * as further packets may resolve the mapping of the second half of data.
+ *
+ * Inspired by tcp_fragment().
+ */
+static int mptcp_skb_split_tail(struct sk_buff *skb, struct sock *sk, u32 seq)
+{
+       struct sk_buff *buff;
+       int nsize;
+       int nlen, len;
+
+       len = seq - TCP_SKB_CB(skb)->seq;
+       nsize = skb_headlen(skb) - len + tcp_sk(sk)->tcp_header_len;
+       if (nsize < 0)
+               nsize = 0;
+
+       /* Get a new skb... force flag on. */
+       buff = alloc_skb(nsize, GFP_ATOMIC);
+       if (buff == NULL)
+               return -ENOMEM;
+
+       skb_reserve(buff, tcp_sk(sk)->tcp_header_len);
+       skb_reset_transport_header(buff);
+
+       tcp_hdr(buff)->fin = tcp_hdr(skb)->fin;
+       tcp_hdr(skb)->fin = 0;
+
+       /* We absolutly need to call skb_set_owner_r before refreshing the
+        * truesize of buff, otherwise the moved data will account twice.
+        */
+       skb_set_owner_r(buff, sk);
+       nlen = skb->len - len - nsize;
+       buff->truesize += nlen;
+       skb->truesize -= nlen;
+
+       /* Correct the sequence numbers. */
+       TCP_SKB_CB(buff)->seq = TCP_SKB_CB(skb)->seq + len;
+       TCP_SKB_CB(buff)->end_seq = TCP_SKB_CB(skb)->end_seq;
+       TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(buff)->seq;
+
+       skb_split(skb, buff, len);
+
+       __skb_queue_after(&sk->sk_receive_queue, skb, buff);
+
+       return 0;
+}
+
+/* @return: 0  everything is fine. Just continue processing
+ *         1  subflow is broken stop everything
+ *         -1 this packet was broken - continue with the next one.
+ */
+static int mptcp_prevalidate_skb(struct sock *sk, struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       /* If we are in infinite mode, the subflow-fin is in fact a data-fin. */
+       if (!skb->len && tcp_hdr(skb)->fin && !mptcp_is_data_fin(skb) &&
+           !tp->mpcb->infinite_mapping_rcv) {
+               /* Remove a pure subflow-fin from the queue and increase
+                * copied_seq.
+                */
+               tp->copied_seq = TCP_SKB_CB(skb)->end_seq;
+               __skb_unlink(skb, &sk->sk_receive_queue);
+               __kfree_skb(skb);
+               return -1;
+       }
+
+       /* If we are not yet fully established and do not know the mapping for
+        * this segment, this path has to fallback to infinite or be torn down.
+        */
+       if (!tp->mptcp->fully_established && !mptcp_is_data_seq(skb) &&
+           !tp->mptcp->mapping_present && !tp->mpcb->infinite_mapping_rcv) {
+               pr_err("%s %#x will fallback - pi %d from %pS, seq %u\n",
+                      __func__, tp->mpcb->mptcp_loc_token,
+                      tp->mptcp->path_index, __builtin_return_address(0),
+                      TCP_SKB_CB(skb)->seq);
+
+               if (!is_master_tp(tp)) {
+                       mptcp_send_reset(sk);
+                       return 1;
+               }
+
+               tp->mpcb->infinite_mapping_snd = 1;
+               tp->mpcb->infinite_mapping_rcv = 1;
+               tp->mptcp->fully_established = 1;
+       }
+
+       /* Receiver-side becomes fully established when a whole rcv-window has
+        * been received without the need to fallback due to the previous
+        * condition. */
+       if (!tp->mptcp->fully_established) {
+               tp->mptcp->init_rcv_wnd -= skb->len;
+               if (tp->mptcp->init_rcv_wnd < 0)
+                       mptcp_become_fully_estab(sk);
+       }
+
+       return 0;
+}
+
+/* @return: 0  everything is fine. Just continue processing
+ *         1  subflow is broken stop everything
+ *         -1 this packet was broken - continue with the next one.
+ */
+static int mptcp_detect_mapping(struct sock *sk, struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk), *meta_tp = mptcp_meta_tp(tp);
+       struct mptcp_cb *mpcb = tp->mpcb;
+       struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+       u32 *ptr;
+       u32 data_seq, sub_seq, data_len, tcp_end_seq;
+
+       /* If we are in infinite-mapping-mode, the subflow is guaranteed to be
+        * in-order at the data-level. Thus data-seq-numbers can be inferred
+        * from what is expected at the data-level.
+        */
+       if (mpcb->infinite_mapping_rcv) {
+               tp->mptcp->map_data_seq = mptcp_get_rcv_nxt_64(meta_tp);
+               tp->mptcp->map_subseq = tcb->seq;
+               tp->mptcp->map_data_len = skb->len;
+               tp->mptcp->map_data_fin = tcp_hdr(skb)->fin;
+               tp->mptcp->mapping_present = 1;
+               return 0;
+       }
+
+       /* No mapping here? Exit - it is either already set or still on its way */
+       if (!mptcp_is_data_seq(skb)) {
+               /* Too many packets without a mapping - this subflow is broken */
+               if (!tp->mptcp->mapping_present &&
+                   tp->rcv_nxt - tp->copied_seq > 65536) {
+                       mptcp_send_reset(sk);
+                       return 1;
+               }
+
+               return 0;
+       }
+
+       ptr = mptcp_skb_set_data_seq(skb, &data_seq, mpcb);
+       ptr++;
+       sub_seq = get_unaligned_be32(ptr) + tp->mptcp->rcv_isn;
+       ptr++;
+       data_len = get_unaligned_be16(ptr);
+
+       /* If it's an empty skb with DATA_FIN, sub_seq must get fixed.
+        * The draft sets it to 0, but we really would like to have the
+        * real value, to have an easy handling afterwards here in this
+        * function.
+        */
+       if (mptcp_is_data_fin(skb) && skb->len == 0)
+               sub_seq = TCP_SKB_CB(skb)->seq;
+
+       /* If there is already a mapping - we check if it maps with the current
+        * one. If not - we reset.
+        */
+       if (tp->mptcp->mapping_present &&
+           (data_seq != (u32)tp->mptcp->map_data_seq ||
+            sub_seq != tp->mptcp->map_subseq ||
+            data_len != tp->mptcp->map_data_len + tp->mptcp->map_data_fin ||
+            mptcp_is_data_fin(skb) != tp->mptcp->map_data_fin)) {
+               /* Mapping in packet is different from what we want */
+               pr_err("%s Mappings do not match!\n", __func__);
+               pr_err("%s dseq %u mdseq %u, sseq %u msseq %u dlen %u mdlen %u dfin %d mdfin %d\n",
+                      __func__, data_seq, (u32)tp->mptcp->map_data_seq,
+                      sub_seq, tp->mptcp->map_subseq, data_len,
+                      tp->mptcp->map_data_len, mptcp_is_data_fin(skb),
+                      tp->mptcp->map_data_fin);
+               mptcp_send_reset(sk);
+               return 1;
+       }
+
+       /* If the previous check was good, the current mapping is valid and we exit. */
+       if (tp->mptcp->mapping_present)
+               return 0;
+
+       /* Mapping not yet set on this subflow - we set it here! */
+
+       if (!data_len) {
+               mpcb->infinite_mapping_rcv = 1;
+               tp->mptcp->fully_established = 1;
+               /* We need to repeat mp_fail's until the sender felt
+                * back to infinite-mapping - here we stop repeating it.
+                */
+               tp->mptcp->send_mp_fail = 0;
+
+               /* We have to fixup data_len - it must be the same as skb->len */
+               data_len = skb->len + (mptcp_is_data_fin(skb) ? 1 : 0);
+               sub_seq = tcb->seq;
+
+               /* TODO kill all other subflows than this one */
+               /* data_seq and so on are set correctly */
+
+               /* At this point, the meta-ofo-queue has to be emptied,
+                * as the following data is guaranteed to be in-order at
+                * the data and subflow-level
+                */
+               mptcp_purge_ofo_queue(meta_tp);
+       }
+
+       /* We are sending mp-fail's and thus are in fallback mode.
+        * Ignore packets which do not announce the fallback and still
+        * want to provide a mapping.
+        */
+       if (tp->mptcp->send_mp_fail) {
+               tp->copied_seq = TCP_SKB_CB(skb)->end_seq;
+               __skb_unlink(skb, &sk->sk_receive_queue);
+               __kfree_skb(skb);
+               return -1;
+       }
+
+       /* FIN increased the mapping-length by 1 */
+       if (mptcp_is_data_fin(skb))
+               data_len--;
+
+       /* Subflow-sequences of packet must be
+        * (at least partially) be part of the DSS-mapping's
+        * subflow-sequence-space.
+        *
+        * Basically the mapping is not valid, if either of the
+        * following conditions is true:
+        *
+        * 1. It's not a data_fin and
+        *    MPTCP-sub_seq >= TCP-end_seq
+        *
+        * 2. It's a data_fin and TCP-end_seq > TCP-seq and
+        *    MPTCP-sub_seq >= TCP-end_seq
+        *
+        * The previous two can be merged into:
+        *    TCP-end_seq > TCP-seq and MPTCP-sub_seq >= TCP-end_seq
+        *    Because if it's not a data-fin, TCP-end_seq > TCP-seq
+        *
+        * 3. It's a data_fin and skb->len == 0 and
+        *    MPTCP-sub_seq > TCP-end_seq
+        *
+        * 4. It's not a data_fin and TCP-end_seq > TCP-seq and
+        *    MPTCP-sub_seq + MPTCP-data_len <= TCP-seq
+        *
+        * 5. MPTCP-sub_seq is prior to what we already copied (copied_seq)
+        */
+
+       /* subflow-fin is not part of the mapping - ignore it here ! */
+       tcp_end_seq = tcb->end_seq - tcp_hdr(skb)->fin;
+       if ((!before(sub_seq, tcb->end_seq) && after(tcp_end_seq, tcb->seq)) ||
+           (mptcp_is_data_fin(skb) && skb->len == 0 && after(sub_seq, tcb->end_seq)) ||
+           (!after(sub_seq + data_len, tcb->seq) && after(tcp_end_seq, tcb->seq)) ||
+           before(sub_seq, tp->copied_seq)) {
+               /* Subflow-sequences of packet is different from what is in the
+                * packet's dss-mapping. The peer is misbehaving - reset
+                */
+               pr_err("%s Packet's mapping does not map to the DSS sub_seq %u "
+                      "end_seq %u, tcp_end_seq %u seq %u dfin %u len %u data_len %u"
+                      "copied_seq %u\n", __func__, sub_seq, tcb->end_seq, tcp_end_seq, tcb->seq, mptcp_is_data_fin(skb),
+                      skb->len, data_len, tp->copied_seq);
+               mptcp_send_reset(sk);
+               return 1;
+       }
+
+       /* Does the DSS had 64-bit seqnum's ? */
+       if (!(tcb->mptcp_flags & MPTCPHDR_SEQ64_SET)) {
+               /* Wrapped around? */
+               if (unlikely(after(data_seq, meta_tp->rcv_nxt) && data_seq < meta_tp->rcv_nxt)) {
+                       tp->mptcp->map_data_seq = mptcp_get_data_seq_64(mpcb, !mpcb->rcv_hiseq_index, data_seq);
+               } else {
+                       /* Else, access the default high-order bits */
+                       tp->mptcp->map_data_seq = mptcp_get_data_seq_64(mpcb, mpcb->rcv_hiseq_index, data_seq);
+               }
+       } else {
+               tp->mptcp->map_data_seq = mptcp_get_data_seq_64(mpcb, (tcb->mptcp_flags & MPTCPHDR_SEQ64_INDEX) ? 1 : 0, data_seq);
+
+               if (unlikely(tcb->mptcp_flags & MPTCPHDR_SEQ64_OFO)) {
+                       /* We make sure that the data_seq is invalid.
+                        * It will be dropped later.
+                        */
+                       tp->mptcp->map_data_seq += 0xFFFFFFFF;
+                       tp->mptcp->map_data_seq += 0xFFFFFFFF;
+               }
+       }
+
+       tp->mptcp->map_data_len = data_len;
+       tp->mptcp->map_subseq = sub_seq;
+       tp->mptcp->map_data_fin = mptcp_is_data_fin(skb) ? 1 : 0;
+       tp->mptcp->mapping_present = 1;
+
+       return 0;
+}
+
+/* Similar to tcp_sequence(...) */
+static inline int mptcp_sequence(const struct tcp_sock *meta_tp,
+                                u64 data_seq, u64 end_data_seq)
+{
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       u64 rcv_wup64;
+
+       /* Wrap-around? */
+       if (meta_tp->rcv_wup > meta_tp->rcv_nxt) {
+               rcv_wup64 = ((u64)(mpcb->rcv_high_order[mpcb->rcv_hiseq_index] - 1) << 32) |
+                               meta_tp->rcv_wup;
+       } else {
+               rcv_wup64 = mptcp_get_data_seq_64(mpcb, mpcb->rcv_hiseq_index,
+                                                 meta_tp->rcv_wup);
+       }
+
+       return  !before64(end_data_seq, rcv_wup64) &&
+               !after64(data_seq, mptcp_get_rcv_nxt_64(meta_tp) + tcp_receive_window(meta_tp));
+}
+
+/* @return: 0  everything is fine. Just continue processing
+ *         -1 this packet was broken - continue with the next one.
+ */
+static int mptcp_validate_mapping(struct sock *sk, struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sk_buff *tmp, *tmp1;
+       u32 tcp_end_seq;
+
+       if (!tp->mptcp->mapping_present)
+               return 0;
+
+       /* either, the new skb gave us the mapping and the first segment
+        * in the sub-rcv-queue has to be trimmed ...
+        */
+       tmp = skb_peek(&sk->sk_receive_queue);
+       if (before(TCP_SKB_CB(tmp)->seq, tp->mptcp->map_subseq) &&
+           after(TCP_SKB_CB(tmp)->end_seq, tp->mptcp->map_subseq))
+               mptcp_skb_trim_head(tmp, sk, tp->mptcp->map_subseq);
+
+       /* ... or the new skb (tail) has to be split at the end. */
+       tcp_end_seq = TCP_SKB_CB(skb)->end_seq - (tcp_hdr(skb)->fin ? 1 : 0);
+       if (after(tcp_end_seq, tp->mptcp->map_subseq + tp->mptcp->map_data_len)) {
+               u32 seq = tp->mptcp->map_subseq + tp->mptcp->map_data_len;
+               if (mptcp_skb_split_tail(skb, sk, seq)) { /* Allocation failed */
+                       /* TODO : maybe handle this here better.
+                        * We now just force meta-retransmission.
+                        */
+                       tp->copied_seq = TCP_SKB_CB(skb)->end_seq;
+                       __skb_unlink(skb, &sk->sk_receive_queue);
+                       __kfree_skb(skb);
+                       return -1;
+               }
+       }
+
+       /* Now, remove old sk_buff's from the receive-queue.
+        * This may happen if the mapping has been lost for these segments and
+        * the next mapping has already been received.
+        */
+       if (tp->mptcp->mapping_present &&
+           before(TCP_SKB_CB(skb_peek(&sk->sk_receive_queue))->seq, tp->mptcp->map_subseq)) {
+               skb_queue_walk_safe(&sk->sk_receive_queue, tmp1, tmp) {
+                       if (!before(TCP_SKB_CB(tmp1)->seq, tp->mptcp->map_subseq))
+                               break;
+
+                       tp->copied_seq = TCP_SKB_CB(tmp1)->end_seq;
+                       __skb_unlink(tmp1, &sk->sk_receive_queue);
+
+                       /* Impossible that we could free skb here, because his
+                        * mapping is known to be valid from previous checks
+                        */
+                       __kfree_skb(tmp1);
+               }
+       }
+
+       return 0;
+}
+
+/* @return: 0  everything is fine. Just continue processing
+ *         1  subflow is broken stop everything
+ *         -1 this mapping has been put in the meta-receive-queue
+ *         -2 this mapping has been eaten by the application
+ */
+static int mptcp_queue_skb(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk), *meta_tp = mptcp_meta_tp(tp);
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct mptcp_cb *mpcb = tp->mpcb;
+       struct sk_buff *tmp, *tmp1;
+       u64 rcv_nxt64 = mptcp_get_rcv_nxt_64(meta_tp);
+       bool data_queued = false;
+
+       /* Have we not yet received the full mapping? */
+       if (!tp->mptcp->mapping_present ||
+           before(tp->rcv_nxt, tp->mptcp->map_subseq + tp->mptcp->map_data_len))
+               return 0;
+
+       /* Is this an overlapping mapping? rcv_nxt >= end_data_seq
+        * OR
+        * This mapping is out of window
+        */
+       if (!before64(rcv_nxt64, tp->mptcp->map_data_seq + tp->mptcp->map_data_len + tp->mptcp->map_data_fin) ||
+           !mptcp_sequence(meta_tp, tp->mptcp->map_data_seq,
+                           tp->mptcp->map_data_seq + tp->mptcp->map_data_len + tp->mptcp->map_data_fin)) {
+               skb_queue_walk_safe(&sk->sk_receive_queue, tmp1, tmp) {
+                       __skb_unlink(tmp1, &sk->sk_receive_queue);
+                       tp->copied_seq = TCP_SKB_CB(tmp1)->end_seq;
+                       __kfree_skb(tmp1);
+
+                       if (!skb_queue_empty(&sk->sk_receive_queue) &&
+                           !before(TCP_SKB_CB(tmp)->seq,
+                                   tp->mptcp->map_subseq + tp->mptcp->map_data_len))
+                               break;
+               }
+
+               mptcp_reset_mapping(tp);
+
+               return -1;
+       }
+
+       /* Record it, because we want to send our data_fin on the same path */
+       if (tp->mptcp->map_data_fin) {
+               mpcb->dfin_path_index = tp->mptcp->path_index;
+               mpcb->dfin_combined = !!(sk->sk_shutdown & RCV_SHUTDOWN);
+       }
+
+       /* Verify the checksum */
+       if (mpcb->dss_csum && !mpcb->infinite_mapping_rcv) {
+               int ret = mptcp_verif_dss_csum(sk);
+
+               if (ret <= 0) {
+                       mptcp_reset_mapping(tp);
+                       return 1;
+               }
+       }
+
+       if (before64(rcv_nxt64, tp->mptcp->map_data_seq)) {
+               /* Seg's have to go to the meta-ofo-queue */
+               skb_queue_walk_safe(&sk->sk_receive_queue, tmp1, tmp) {
+                       tp->copied_seq = TCP_SKB_CB(tmp1)->end_seq;
+                       mptcp_prepare_skb(tmp1, tmp, sk);
+                       __skb_unlink(tmp1, &sk->sk_receive_queue);
+                       /* MUST be done here, because fragstolen may be true later.
+                        * Then, kfree_skb_partial will not account the memory.
+                        */
+                       skb_orphan(tmp1);
+
+                       if (!mpcb->in_time_wait) /* In time-wait, do not receive data */
+                               mptcp_add_meta_ofo_queue(meta_sk, tmp1, sk);
+                       else
+                               __kfree_skb(tmp1);
+
+                       if (!skb_queue_empty(&sk->sk_receive_queue) &&
+                           !before(TCP_SKB_CB(tmp)->seq,
+                                   tp->mptcp->map_subseq + tp->mptcp->map_data_len))
+                               break;
+
+               }
+       } else {
+               /* Ready for the meta-rcv-queue */
+               skb_queue_walk_safe(&sk->sk_receive_queue, tmp1, tmp) {
+                       int eaten = 0;
+                       int copied_early = 0;
+                       bool fragstolen = false;
+                       u32 old_rcv_nxt = meta_tp->rcv_nxt;
+
+                       tp->copied_seq = TCP_SKB_CB(tmp1)->end_seq;
+                       mptcp_prepare_skb(tmp1, tmp, sk);
+                       __skb_unlink(tmp1, &sk->sk_receive_queue);
+                       /* MUST be done here, because fragstolen may be true.
+                        * Then, kfree_skb_partial will not account the memory.
+                        */
+                       skb_orphan(tmp1);
+
+                       /* This segment has already been received */
+                       if (!after(TCP_SKB_CB(tmp1)->end_seq, meta_tp->rcv_nxt)) {
+                               __kfree_skb(tmp1);
+                               goto next;
+                       }
+
+#ifdef CONFIG_NET_DMA
+                       if (TCP_SKB_CB(tmp1)->seq == meta_tp->rcv_nxt  &&
+                           meta_tp->ucopy.task == current &&
+                           meta_tp->copied_seq == meta_tp->rcv_nxt &&
+                           tmp1->len <= meta_tp->ucopy.len &&
+                           sock_owned_by_user(meta_sk) &&
+                           tcp_dma_try_early_copy(meta_sk, tmp1, 0)) {
+                               copied_early = 1;
+                               eaten = 1;
+                       }
+#endif
+
+                       /* Is direct copy possible ? */
+                       if (TCP_SKB_CB(tmp1)->seq == meta_tp->rcv_nxt &&
+                           meta_tp->ucopy.task == current &&
+                           meta_tp->copied_seq == meta_tp->rcv_nxt &&
+                           meta_tp->ucopy.len && sock_owned_by_user(meta_sk) &&
+                           !copied_early)
+                               eaten = mptcp_direct_copy(tmp1, meta_sk);
+
+                       if (mpcb->in_time_wait) /* In time-wait, do not receive data */
+                               eaten = 1;
+
+                       if (!eaten)
+                               eaten = tcp_queue_rcv(meta_sk, tmp1, 0, &fragstolen);
+
+                       meta_tp->rcv_nxt = TCP_SKB_CB(tmp1)->end_seq;
+                       mptcp_check_rcvseq_wrap(meta_tp, old_rcv_nxt);
+
+                       if (copied_early)
+                               tcp_cleanup_rbuf(meta_sk, tmp1->len);
+
+                       if (tcp_hdr(tmp1)->fin && !mpcb->in_time_wait)
+                               mptcp_fin(meta_sk);
+
+                       /* Check if this fills a gap in the ofo queue */
+                       if (!skb_queue_empty(&meta_tp->out_of_order_queue))
+                               mptcp_ofo_queue(meta_sk);
+
+#ifdef CONFIG_NET_DMA
+                       if (copied_early)
+                               __skb_queue_tail(&meta_sk->sk_async_wait_queue,
+                                                tmp1);
+                       else
+#endif
+                       if (eaten)
+                               kfree_skb_partial(tmp1, fragstolen);
+
+                       data_queued = true;
+next:
+                       if (!skb_queue_empty(&sk->sk_receive_queue) &&
+                           !before(TCP_SKB_CB(tmp)->seq,
+                                   tp->mptcp->map_subseq + tp->mptcp->map_data_len))
+                               break;
+               }
+       }
+
+       inet_csk(meta_sk)->icsk_ack.lrcvtime = tcp_time_stamp;
+       tp->mptcp->last_data_seq = tp->mptcp->map_data_seq;
+       mptcp_reset_mapping(tp);
+
+       return data_queued ? -1 : -2;
+}
+
+void mptcp_data_ready(struct sock *sk, int bytes)
+{
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct sk_buff *skb, *tmp;
+       int queued = 0;
+
+       /* If the meta is already closed, there is no point in pushing data */
+       if (meta_sk->sk_state == TCP_CLOSE && !tcp_sk(sk)->mpcb->in_time_wait) {
+               skb_queue_purge(&sk->sk_receive_queue);
+               tcp_sk(sk)->copied_seq = tcp_sk(sk)->rcv_nxt;
+               goto exit;
+       }
+
+restart:
+       /* Iterate over all segments, detect their mapping (if we don't have
+        * one yet), validate them and push everything one level higher.
+        */
+       skb_queue_walk_safe(&sk->sk_receive_queue, skb, tmp) {
+               int ret;
+               /* Pre-validation - e.g., early fallback */
+               ret = mptcp_prevalidate_skb(sk, skb);
+               if (ret < 0)
+                       goto restart;
+               else if (ret > 0)
+                       break;
+
+               /* Set the current mapping */
+               ret = mptcp_detect_mapping(sk, skb);
+               if (ret < 0)
+                       goto restart;
+               else if (ret > 0)
+                       break;
+
+               /* Validation */
+               if (mptcp_validate_mapping(sk, skb) < 0)
+                       goto restart;
+
+               /* Push a level higher */
+               ret = mptcp_queue_skb(sk);
+               if (ret < 0) {
+                       if (ret == -1)
+                               queued = ret;
+                       goto restart;
+               } else if (ret == 0) {
+                       continue;
+               } else { /* ret == 1 */
+                       break;
+               }
+       }
+
+exit:
+       if (tcp_sk(sk)->close_it) {
+               tcp_send_ack(sk);
+               tcp_time_wait(sk, TCP_TIME_WAIT, 0);
+       }
+
+       if (queued == -1 && !sock_flag(meta_sk, SOCK_DEAD))
+               meta_sk->sk_data_ready(meta_sk, 0);
+}
+
+
+int mptcp_check_req(struct sk_buff *skb, struct net *net)
+{
+       struct tcphdr *th = tcp_hdr(skb);
+       struct sock *meta_sk = NULL;
+
+       /* MPTCP structures not initialized */
+       if (mptcp_init_failed)
+               return 0;
+
+       if (skb->protocol == htons(ETH_P_IP))
+               meta_sk = mptcp_v4_search_req(th->source, ip_hdr(skb)->saddr,
+                                             ip_hdr(skb)->daddr, net);
+#if IS_ENABLED(CONFIG_IPV6)
+       else /* IPv6 */
+               meta_sk = mptcp_v6_search_req(th->source, &ipv6_hdr(skb)->saddr,
+                                             &ipv6_hdr(skb)->daddr, net);
+#endif /* CONFIG_IPV6 */
+
+       if (!meta_sk)
+               return 0;
+
+       TCP_SKB_CB(skb)->mptcp_flags = MPTCPHDR_JOIN;
+
+       bh_lock_sock_nested(meta_sk);
+       if (sock_owned_by_user(meta_sk)) {
+               skb->sk = meta_sk;
+               if (unlikely(sk_add_backlog(meta_sk, skb,
+                                           meta_sk->sk_rcvbuf + meta_sk->sk_sndbuf))) {
+                       bh_unlock_sock(meta_sk);
+                       NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
+                       sock_put(meta_sk); /* Taken by mptcp_search_req */
+                       kfree_skb(skb);
+                       return 1;
+               }
+       } else if (skb->protocol == htons(ETH_P_IP)) {
+               tcp_v4_do_rcv(meta_sk, skb);
+#if IS_ENABLED(CONFIG_IPV6)
+       } else { /* IPv6 */
+               tcp_v6_do_rcv(meta_sk, skb);
+#endif /* CONFIG_IPV6 */
+       }
+       bh_unlock_sock(meta_sk);
+       sock_put(meta_sk); /* Taken by mptcp_vX_search_req */
+       return 1;
+}
+
+struct mp_join *mptcp_find_join(struct sk_buff *skb)
+{
+       struct tcphdr *th = tcp_hdr(skb);
+       unsigned char *ptr;
+       int length = (th->doff * 4) - sizeof(struct tcphdr);
+
+       /* Jump through the options to check whether JOIN is there */
+       ptr = (unsigned char *)(th + 1);
+       while (length > 0) {
+               int opcode = *ptr++;
+               int opsize;
+
+               switch (opcode) {
+               case TCPOPT_EOL:
+                       return NULL;
+               case TCPOPT_NOP:        /* Ref: RFC 793 section 3.1 */
+                       length--;
+                       continue;
+               default:
+                       opsize = *ptr++;
+                       if (opsize < 2) /* "silly options" */
+                               return NULL;
+                       if (opsize > length)
+                               return NULL;  /* don't parse partial options */
+                       if (opcode == TCPOPT_MPTCP &&
+                           ((struct mptcp_option *)(ptr - 2))->sub == MPTCP_SUB_JOIN) {
+                               return (struct mp_join *)(ptr - 2);
+                       }
+                       ptr += opsize - 2;
+                       length -= opsize;
+               }
+       }
+       return NULL;
+}
+
+int mptcp_lookup_join(struct sk_buff *skb, struct inet_timewait_sock *tw)
+{
+       struct mptcp_cb *mpcb;
+       struct sock *meta_sk;
+       u32 token;
+       struct mp_join *join_opt = mptcp_find_join(skb);
+       if (!join_opt)
+               return 0;
+
+       /* MPTCP structures were not initialized, so return error */
+       if (mptcp_init_failed)
+               return -1;
+
+       token = join_opt->u.syn.token;
+       meta_sk = mptcp_hash_find(dev_net(skb_dst(skb)->dev), token);
+       if (!meta_sk) {
+               mptcp_debug("%s:mpcb not found:%x\n", __func__, token);
+               return -1;
+       }
+
+       mpcb = tcp_sk(meta_sk)->mpcb;
+       if (mpcb->infinite_mapping_rcv || mpcb->send_infinite_mapping) {
+               /* We are in fallback-mode on the reception-side -
+                * no new subflows!
+                */
+               sock_put(meta_sk); /* Taken by mptcp_hash_find */
+               return -1;
+       }
+
+       /* Coming from time-wait-sock processing in tcp_v4_rcv.
+        * We have to deschedule it before continuing, because otherwise
+        * mptcp_v4_do_rcv will hit again on it inside tcp_v4_hnd_req.
+        */
+       if (tw) {
+               inet_twsk_deschedule(tw, &tcp_death_row);
+               inet_twsk_put(tw);
+       }
+
+       TCP_SKB_CB(skb)->mptcp_flags = MPTCPHDR_JOIN;
+       /* OK, this is a new syn/join, let's create a new open request and
+        * send syn+ack
+        */
+       bh_lock_sock_nested(meta_sk);
+       if (sock_owned_by_user(meta_sk)) {
+               skb->sk = meta_sk;
+               if (unlikely(sk_add_backlog(meta_sk, skb,
+                                           meta_sk->sk_rcvbuf + meta_sk->sk_sndbuf))) {
+                       bh_unlock_sock(meta_sk);
+                       NET_INC_STATS_BH(sock_net(meta_sk),
+                                        LINUX_MIB_TCPBACKLOGDROP);
+                       sock_put(meta_sk); /* Taken by mptcp_hash_find */
+                       kfree_skb(skb);
+                       return 1;
+               }
+       } else if (skb->protocol == htons(ETH_P_IP)) {
+               tcp_v4_do_rcv(meta_sk, skb);
+#if IS_ENABLED(CONFIG_IPV6)
+       } else {
+               tcp_v6_do_rcv(meta_sk, skb);
+#endif /* CONFIG_IPV6 */
+       }
+       bh_unlock_sock(meta_sk);
+       sock_put(meta_sk); /* Taken by mptcp_hash_find */
+       return 1;
+}
+
+int mptcp_do_join_short(struct sk_buff *skb, struct mptcp_options_received *mopt,
+                       struct tcp_options_received *tmp_opt, struct net *net)
+{
+       struct sock *meta_sk;
+       u32 token;
+
+       token = mopt->mptcp_rem_token;
+       meta_sk = mptcp_hash_find(net, token);
+       if (!meta_sk) {
+               mptcp_debug("%s:mpcb not found:%x\n", __func__, token);
+               return -1;
+       }
+
+       TCP_SKB_CB(skb)->mptcp_flags = MPTCPHDR_JOIN;
+
+       /* OK, this is a new syn/join, let's create a new open request and
+        * send syn+ack
+        */
+       bh_lock_sock(meta_sk);
+
+       /* This check is also done in mptcp_vX_do_rcv. But, there we cannot
+        * call tcp_vX_send_reset, because we hold already two socket-locks.
+        * (the listener and the meta from above)
+        *
+        * And the send-reset will try to take yet another one (ip_send_reply).
+        * Thus, we propagate the reset up to tcp_rcv_state_process.
+        */
+       if (tcp_sk(meta_sk)->mpcb->infinite_mapping_rcv ||
+           tcp_sk(meta_sk)->mpcb->send_infinite_mapping ||
+           meta_sk->sk_state == TCP_CLOSE || !tcp_sk(meta_sk)->inside_tk_table) {
+               bh_unlock_sock(meta_sk);
+               sock_put(meta_sk); /* Taken by mptcp_hash_find */
+               return -1;
+       }
+
+       if (sock_owned_by_user(meta_sk)) {
+               skb->sk = meta_sk;
+               if (unlikely(sk_add_backlog(meta_sk, skb,
+                                           meta_sk->sk_rcvbuf + meta_sk->sk_sndbuf)))
+                       NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
+               else
+                       /* Must make sure that upper layers won't free the
+                        * skb if it is added to the backlog-queue.
+                        */
+                       skb_get(skb);
+       } else {
+               /* mptcp_v4_do_rcv tries to free the skb - we prevent this, as
+                * the skb will finally be freed by tcp_v4_do_rcv (where we are
+                * coming from)
+                */
+               skb_get(skb);
+               if (skb->protocol == htons(ETH_P_IP)) {
+                       tcp_v4_do_rcv(meta_sk, skb);
+#if IS_ENABLED(CONFIG_IPV6)
+               } else { /* IPv6 */
+                       tcp_v6_do_rcv(meta_sk, skb);
+#endif /* CONFIG_IPV6 */
+               }
+       }
+
+       bh_unlock_sock(meta_sk);
+       sock_put(meta_sk); /* Taken by mptcp_hash_find */
+       return 0;
+}
+
+/**
+ * Equivalent of tcp_fin() for MPTCP
+ * Can be called only when the FIN is validly part
+ * of the data seqnum space. Not before when we get holes.
+ */
+void mptcp_fin(struct sock *meta_sk)
+{
+       struct sock *sk = NULL, *sk_it;
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+
+       mptcp_for_each_sk(mpcb, sk_it) {
+               if (tcp_sk(sk_it)->mptcp->path_index == mpcb->dfin_path_index) {
+                       sk = sk_it;
+                       break;
+               }
+       }
+
+       if (!sk || sk->sk_state == TCP_CLOSE)
+               sk = mptcp_select_ack_sock(meta_sk, 0);
+
+       inet_csk_schedule_ack(sk);
+
+       meta_sk->sk_shutdown |= RCV_SHUTDOWN;
+       sock_set_flag(meta_sk, SOCK_DONE);
+
+       switch (meta_sk->sk_state) {
+       case TCP_SYN_RECV:
+       case TCP_ESTABLISHED:
+               /* Move to CLOSE_WAIT */
+               tcp_set_state(meta_sk, TCP_CLOSE_WAIT);
+               inet_csk(sk)->icsk_ack.pingpong = 1;
+               break;
+
+       case TCP_CLOSE_WAIT:
+       case TCP_CLOSING:
+               /* Received a retransmission of the FIN, do
+                * nothing.
+                */
+               break;
+       case TCP_LAST_ACK:
+               /* RFC793: Remain in the LAST-ACK state. */
+               break;
+
+       case TCP_FIN_WAIT1:
+               /* This case occurs when a simultaneous close
+                * happens, we must ack the received FIN and
+                * enter the CLOSING state.
+                */
+               tcp_send_ack(sk);
+               tcp_set_state(meta_sk, TCP_CLOSING);
+               break;
+       case TCP_FIN_WAIT2:
+               /* Received a FIN -- send ACK and enter TIME_WAIT. */
+               tcp_send_ack(sk);
+               tcp_time_wait(meta_sk, TCP_TIME_WAIT, 0);
+               break;
+       default:
+               /* Only TCP_LISTEN and TCP_CLOSE are left, in these
+                * cases we should never reach this piece of code.
+                */
+               pr_err("%s: Impossible, meta_sk->sk_state=%d\n", __func__,
+                      meta_sk->sk_state);
+               break;
+       }
+
+       /* It _is_ possible, that we have something out-of-order _after_ FIN.
+        * Probably, we should reset in this case. For now drop them.
+        */
+       mptcp_purge_ofo_queue(meta_tp);
+       sk_mem_reclaim(meta_sk);
+
+       if (!sock_flag(meta_sk, SOCK_DEAD)) {
+               meta_sk->sk_state_change(meta_sk);
+
+               /* Do not send POLL_HUP for half duplex close. */
+               if (meta_sk->sk_shutdown == SHUTDOWN_MASK ||
+                   meta_sk->sk_state == TCP_CLOSE)
+                       sk_wake_async(meta_sk, SOCK_WAKE_WAITD, POLL_HUP);
+               else
+                       sk_wake_async(meta_sk, SOCK_WAKE_WAITD, POLL_IN);
+       }
+
+       return;
+}
+
+static void mptcp_xmit_retransmit_queue(struct sock *meta_sk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sk_buff *skb;
+
+       if (!meta_tp->packets_out)
+               return;
+
+       tcp_for_write_queue(skb, meta_sk) {
+               if (skb == tcp_send_head(meta_sk))
+                       break;
+
+               if (mptcp_retransmit_skb(meta_sk, skb))
+                       return;
+
+               if (skb == tcp_write_queue_head(meta_sk))
+                       inet_csk_reset_xmit_timer(meta_sk, ICSK_TIME_RETRANS,
+                                                 inet_csk(meta_sk)->icsk_rto,
+                                                 TCP_RTO_MAX);
+       }
+}
+
+/* Handle the DATA_ACK */
+static void mptcp_data_ack(struct sock *sk, const struct sk_buff *skb)
+{
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk), *tp = tcp_sk(sk);
+       struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+       u32 prior_snd_una = meta_tp->snd_una;
+       int prior_packets;
+       u32 nwin, data_ack, data_seq;
+       u16 data_len = 0;
+
+       /* A valid packet came in - subflow is operational again */
+       tp->pf = 0;
+
+       /* Even if there is no data-ack, we stop retransmitting.
+        * Except if this is a SYN/ACK. Then it is just a retransmission
+        */
+       if (tp->mptcp->pre_established && !tcp_hdr(skb)->syn) {
+               tp->mptcp->pre_established = 0;
+               sk_stop_timer(sk, &tp->mptcp->mptcp_ack_timer);
+       }
+
+       /* If we are in infinite mapping mode, rx_opt.data_ack has been
+        * set by mptcp_clean_rtx_infinite.
+        */
+       if (!(tcb->mptcp_flags & MPTCPHDR_ACK) && !tp->mpcb->infinite_mapping_snd)
+               goto exit;
+
+       data_ack = tp->mptcp->rx_opt.data_ack;
+
+       if (unlikely(!tp->mptcp->fully_established) &&
+           (data_ack != meta_tp->mptcp->snt_isn ||
+           tp->mptcp->snt_isn + 1 != TCP_SKB_CB(skb)->ack_seq))
+               /* As soon as data has been data-acked,
+                * or a subflow-data-ack (not acking syn - thus snt_isn + 1)
+                * includes a data-ack, we are fully established
+                */
+               mptcp_become_fully_estab(sk);
+
+       /* Get the data_seq */
+       if (mptcp_is_data_seq(skb)) {
+               data_seq = tp->mptcp->rx_opt.data_seq;
+               data_len = tp->mptcp->rx_opt.data_len;
+       } else {
+               data_seq = meta_tp->snd_wl1;
+       }
+
+       /* If the ack is older than previous acks
+        * then we can probably ignore it.
+        */
+       if (before(data_ack, prior_snd_una))
+               goto exit;
+
+       /* If the ack includes data we haven't sent yet, discard
+        * this segment (RFC793 Section 3.9).
+        */
+       if (after(data_ack, meta_tp->snd_nxt))
+               goto exit;
+
+       /*** Now, update the window  - inspired by tcp_ack_update_window ***/
+       nwin = ntohs(tcp_hdr(skb)->window);
+
+       if (likely(!tcp_hdr(skb)->syn))
+               nwin <<= tp->rx_opt.snd_wscale;
+
+       if (tcp_may_update_window(meta_tp, data_ack, data_seq, nwin)) {
+               tcp_update_wl(meta_tp, data_seq);
+
+               /* Draft v09, Section 3.3.5:
+                * [...] It should only update its local receive window values
+                * when the largest sequence number allowed (i.e.  DATA_ACK +
+                * receive window) increases. [...]
+                */
+               if (meta_tp->snd_wnd != nwin &&
+                   !before(data_ack + nwin, tcp_wnd_end(meta_tp))) {
+                       meta_tp->snd_wnd = nwin;
+
+                       if (nwin > meta_tp->max_window)
+                               meta_tp->max_window = nwin;
+               }
+       }
+       /*** Done, update the window ***/
+
+       /* We passed data and got it acked, remove any soft error
+        * log. Something worked...
+        */
+       sk->sk_err_soft = 0;
+       inet_csk(meta_sk)->icsk_probes_out = 0;
+       meta_tp->rcv_tstamp = tcp_time_stamp;
+       prior_packets = meta_tp->packets_out;
+       if (!prior_packets)
+               goto no_queue;
+
+       meta_tp->snd_una = data_ack;
+
+       mptcp_clean_rtx_queue(meta_sk, prior_snd_una);
+
+       /* We are in loss-state, and something got acked, retransmit the whole
+        * queue now!
+        */
+       if (inet_csk(meta_sk)->icsk_ca_state == TCP_CA_Loss &&
+           after(data_ack, prior_snd_una)) {
+               mptcp_xmit_retransmit_queue(meta_sk);
+               inet_csk(meta_sk)->icsk_ca_state = TCP_CA_Open;
+       }
+
+       /* Simplified version of tcp_new_space, because the snd-buffer
+        * is handled by all the subflows.
+        */
+       if (sock_flag(meta_sk, SOCK_QUEUE_SHRUNK)) {
+               sock_reset_flag(meta_sk, SOCK_QUEUE_SHRUNK);
+               if (meta_sk->sk_socket &&
+                   test_bit(SOCK_NOSPACE, &meta_sk->sk_socket->flags))
+                       meta_sk->sk_write_space(meta_sk);
+       }
+
+       if (meta_sk->sk_state != TCP_ESTABLISHED &&
+           mptcp_rcv_state_process(meta_sk, sk, skb, data_seq, data_len))
+               return;
+
+exit:
+       mptcp_push_pending_frames(meta_sk);
+
+       return;
+
+no_queue:
+       if (tcp_send_head(meta_sk))
+               tcp_ack_probe(meta_sk);
+
+       mptcp_push_pending_frames(meta_sk);
+
+       return;
+}
+
+void mptcp_clean_rtx_infinite(struct sk_buff *skb, struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk), *meta_tp = tcp_sk(mptcp_meta_sk(sk));
+
+       if (!tp->mpcb->infinite_mapping_snd)
+               return;
+
+       /* The difference between both write_seq's represents the offset between
+        * data-sequence and subflow-sequence. As we are infinite, this must
+        * match.
+        *
+        * Thus, from this difference we can infer the meta snd_una.
+        */
+       tp->mptcp->rx_opt.data_ack = meta_tp->snd_nxt - tp->snd_nxt +
+                                    tp->snd_una;
+
+       mptcp_data_ack(sk, skb);
+}
+
+/**** static functions used by mptcp_parse_options */
+
+static inline int mptcp_rem_raddress(struct mptcp_cb *mpcb, u8 rem_id)
+{
+       if (mptcp_v4_rem_raddress(mpcb, rem_id) < 0) {
+#if IS_ENABLED(CONFIG_IPV6)
+               if (mptcp_v6_rem_raddress(mpcb, rem_id) < 0)
+                       return -1;
+#else
+               return -1;
+#endif /* CONFIG_IPV6 */
+       }
+       return 0;
+}
+
+static void mptcp_send_reset_rem_id(const struct mptcp_cb *mpcb, u8 rem_id)
+{
+       struct sock *sk_it, *tmpsk;
+
+       mptcp_for_each_sk_safe(mpcb, sk_it, tmpsk) {
+               if (tcp_sk(sk_it)->mptcp->rem_id == rem_id) {
+                       mptcp_reinject_data(sk_it, 0);
+                       sk_it->sk_err = ECONNRESET;
+                       if (tcp_need_reset(sk_it->sk_state))
+                               tcp_send_active_reset(sk_it, GFP_ATOMIC);
+                       mptcp_sub_force_close(sk_it);
+               }
+       }
+}
+
+void mptcp_parse_options(const uint8_t *ptr, int opsize,
+                        struct tcp_options_received *opt_rx,
+                        struct mptcp_options_received *mopt,
+                        const struct sk_buff *skb)
+{
+       struct mptcp_option *mp_opt = (struct mptcp_option *)ptr;
+
+       /* If the socket is mp-capable we would have a mopt. */
+       if (!mopt)
+               return;
+
+       switch (mp_opt->sub) {
+       case MPTCP_SUB_CAPABLE:
+       {
+               struct mp_capable *mpcapable = (struct mp_capable *)ptr;
+
+               if (opsize != MPTCP_SUB_LEN_CAPABLE_SYN &&
+                   opsize != MPTCP_SUB_LEN_CAPABLE_ACK) {
+                       mptcp_debug("%s: mp_capable: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+
+               if (!sysctl_mptcp_enabled)
+                       break;
+
+               /* We only support MPTCP version 0 */
+               if (mpcapable->ver != 0)
+                       break;
+
+               /* MPTCP-RFC 6824:
+                * "If receiving a message with the 'B' flag set to 1, and this
+                * is not understood, then this SYN MUST be silently ignored;
+                */
+               if (mpcapable->b) {
+                       mopt->drop_me = 1;
+                       break;
+               }
+
+               /* MPTCP-RFC 6824:
+                * "An implementation that only supports this method MUST set
+                *  bit "H" to 1, and bits "C" through "G" to 0."
+                */
+               if (!mpcapable->h)
+                       break;
+
+               mopt->saw_mpc = 1;
+               mopt->dss_csum = sysctl_mptcp_checksum || mpcapable->a;
+
+               if (opsize >= MPTCP_SUB_LEN_CAPABLE_SYN)
+                       mopt->mptcp_key = mpcapable->sender_key;
+
+               break;
+       }
+       case MPTCP_SUB_JOIN:
+       {
+               struct mp_join *mpjoin = (struct mp_join *)ptr;
+
+               if (opsize != MPTCP_SUB_LEN_JOIN_SYN &&
+                   opsize != MPTCP_SUB_LEN_JOIN_SYNACK &&
+                   opsize != MPTCP_SUB_LEN_JOIN_ACK) {
+                       mptcp_debug("%s: mp_join: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+
+               /* saw_mpc must be set, because in tcp_check_req we assume that
+                * it is set to support falling back to reg. TCP if a rexmitted
+                * SYN has no MP_CAPABLE or MP_JOIN
+                */
+               switch (opsize) {
+               case MPTCP_SUB_LEN_JOIN_SYN:
+                       mopt->is_mp_join = 1;
+                       mopt->saw_mpc = 1;
+                       mopt->low_prio = mpjoin->b;
+                       mopt->rem_id = mpjoin->addr_id;
+                       mopt->mptcp_rem_token = mpjoin->u.syn.token;
+                       mopt->mptcp_recv_nonce = mpjoin->u.syn.nonce;
+                       break;
+               case MPTCP_SUB_LEN_JOIN_SYNACK:
+                       mopt->saw_mpc = 1;
+                       mopt->low_prio = mpjoin->b;
+                       mopt->rem_id = mpjoin->addr_id;
+                       mopt->mptcp_recv_tmac = mpjoin->u.synack.mac;
+                       mopt->mptcp_recv_nonce = mpjoin->u.synack.nonce;
+                       break;
+               case MPTCP_SUB_LEN_JOIN_ACK:
+                       mopt->saw_mpc = 1;
+                       mopt->join_ack = 1;
+                       memcpy(mopt->mptcp_recv_mac, mpjoin->u.ack.mac, 20);
+                       break;
+               }
+               break;
+       }
+       case MPTCP_SUB_DSS:
+       {
+               struct mp_dss *mdss = (struct mp_dss *)ptr;
+               struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+
+               /* We check opsize for the csum and non-csum case. We do this,
+                * because the draft says that the csum SHOULD be ignored if
+                * it has not been negotiated in the MP_CAPABLE but still is
+                * present in the data.
+                *
+                * It will get ignored later in mptcp_queue_skb.
+                */
+               if (opsize != mptcp_sub_len_dss(mdss, 0) &&
+                   opsize != mptcp_sub_len_dss(mdss, 1)) {
+                       mptcp_debug("%s: mp_dss: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+
+               ptr += 4;
+
+               if (mdss->A) {
+                       tcb->mptcp_flags |= MPTCPHDR_ACK;
+
+                       if (mdss->a) {
+                               mopt->data_ack = (u32) get_unaligned_be64(ptr);
+                               ptr += MPTCP_SUB_LEN_ACK_64;
+                       } else {
+                               mopt->data_ack = get_unaligned_be32(ptr);
+                               ptr += MPTCP_SUB_LEN_ACK;
+                       }
+               }
+
+               tcb->dss_off = (ptr - skb_transport_header(skb));
+
+               if (mdss->M) {
+                       if (mdss->m) {
+                               u64 data_seq64 = get_unaligned_be64(ptr);
+
+                               tcb->mptcp_flags |= MPTCPHDR_SEQ64_SET;
+                               mopt->data_seq = (u32) data_seq64;
+
+                               ptr += 12; /* 64-bit dseq + subseq */
+                       } else {
+                               mopt->data_seq = get_unaligned_be32(ptr);
+                               ptr += 8; /* 32-bit dseq + subseq */
+                       }
+                       mopt->data_len = get_unaligned_be16(ptr);
+
+                       tcb->mptcp_flags |= MPTCPHDR_SEQ;
+
+                       /* Is a check-sum present? */
+                       if (opsize == mptcp_sub_len_dss(mdss, 1))
+                               tcb->mptcp_flags |= MPTCPHDR_DSS_CSUM;
+
+                       /* DATA_FIN only possible with DSS-mapping */
+                       if (mdss->F)
+                               tcb->mptcp_flags |= MPTCPHDR_FIN;
+               }
+
+               break;
+       }
+       case MPTCP_SUB_ADD_ADDR:
+       {
+#if IS_ENABLED(CONFIG_IPV6)
+               struct mp_add_addr *mpadd = (struct mp_add_addr *)ptr;
+
+               if ((mpadd->ipver == 4 && opsize != MPTCP_SUB_LEN_ADD_ADDR4 &&
+                    opsize != MPTCP_SUB_LEN_ADD_ADDR4 + 2) ||
+                   (mpadd->ipver == 6 && opsize != MPTCP_SUB_LEN_ADD_ADDR6 &&
+                    opsize != MPTCP_SUB_LEN_ADD_ADDR6 + 2)) {
+#else
+               if (opsize != MPTCP_SUB_LEN_ADD_ADDR4 &&
+                   opsize != MPTCP_SUB_LEN_ADD_ADDR4 + 2) {
+#endif /* CONFIG_IPV6 */
+                       mptcp_debug("%s: mp_add_addr: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+
+               /* We have to manually parse the options if we got two of them. */
+               if (mopt->saw_add_addr) {
+                       mopt->more_add_addr = 1;
+                       break;
+               }
+               mopt->saw_add_addr = 1;
+               mopt->add_addr_ptr = ptr;
+               break;
+       }
+       case MPTCP_SUB_REMOVE_ADDR:
+               if ((opsize - MPTCP_SUB_LEN_REMOVE_ADDR) < 0) {
+                       mptcp_debug("%s: mp_remove_addr: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+
+               if (mopt->saw_rem_addr) {
+                       mopt->more_rem_addr = 1;
+                       break;
+               }
+               mopt->saw_rem_addr = 1;
+               mopt->rem_addr_ptr = ptr;
+               break;
+       case MPTCP_SUB_PRIO:
+       {
+               struct mp_prio *mpprio = (struct mp_prio *)ptr;
+
+               if (opsize != MPTCP_SUB_LEN_PRIO &&
+                   opsize != MPTCP_SUB_LEN_PRIO_ADDR) {
+                       mptcp_debug("%s: mp_prio: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+
+               mopt->saw_low_prio = 1;
+               mopt->low_prio = mpprio->b;
+
+               if (opsize == MPTCP_SUB_LEN_PRIO_ADDR) {
+                       mopt->saw_low_prio = 2;
+                       mopt->prio_addr_id = mpprio->addr_id;
+               }
+               break;
+       }
+       case MPTCP_SUB_FAIL:
+               if (opsize != MPTCP_SUB_LEN_FAIL) {
+                       mptcp_debug("%s: mp_fail: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+               mopt->mp_fail = 1;
+               break;
+       case MPTCP_SUB_FCLOSE:
+               if (opsize != MPTCP_SUB_LEN_FCLOSE) {
+                       mptcp_debug("%s: mp_fclose: bad option size %d\n",
+                                   __func__, opsize);
+                       break;
+               }
+
+               mopt->mp_fclose = 1;
+               mopt->mptcp_key = ((struct mp_fclose *)ptr)->key;
+
+               break;
+       default:
+               mptcp_debug("%s: Received unkown subtype: %d\n",
+                           __func__, mp_opt->sub);
+               break;
+       }
+}
+
+int mptcp_check_rtt(const struct tcp_sock *tp, int time)
+{
+       struct mptcp_cb *mpcb = tp->mpcb;
+       struct sock *sk;
+       u32 rtt_max = 0;
+
+       /* In MPTCP, we take the max delay across all flows,
+        * in order to take into account meta-reordering buffers.
+        */
+       mptcp_for_each_sk(mpcb, sk) {
+               if (!mptcp_sk_can_recv(sk))
+                       continue;
+
+               if (rtt_max < tcp_sk(sk)->rcv_rtt_est.rtt)
+                       rtt_max = tcp_sk(sk)->rcv_rtt_est.rtt;
+       }
+       if (time < (rtt_max >> 3) || !rtt_max)
+               return 1;
+
+       return 0;
+}
+
+static void mptcp_handle_add_addr(const unsigned char *ptr, struct sock *sk)
+{
+       struct mp_add_addr *mpadd = (struct mp_add_addr *)ptr;
+
+       if (mpadd->ipver == 4) {
+               __be16 port = 0;
+               if (mpadd->len == MPTCP_SUB_LEN_ADD_ADDR4 + 2)
+                       port  = mpadd->u.v4.port;
+
+               mptcp_v4_add_raddress(tcp_sk(sk)->mpcb, &mpadd->u.v4.addr, port,
+                                     mpadd->addr_id);
+#if IS_ENABLED(CONFIG_IPV6)
+       } else if (mpadd->ipver == 6) {
+               __be16 port = 0;
+               if (mpadd->len == MPTCP_SUB_LEN_ADD_ADDR6 + 2)
+                       port  = mpadd->u.v6.port;
+
+               mptcp_v6_add_raddress(tcp_sk(sk)->mpcb, &mpadd->u.v6.addr, port,
+                                     mpadd->addr_id);
+#endif /* CONFIG_IPV6 */
+       }
+}
+
+static void mptcp_handle_rem_addr(const unsigned char *ptr, struct sock *sk)
+{
+       struct mp_remove_addr *mprem = (struct mp_remove_addr *)ptr;
+       int i;
+       u8 rem_id;
+
+       for (i = 0; i <= mprem->len - MPTCP_SUB_LEN_REMOVE_ADDR; i++) {
+               rem_id = (&mprem->addrs_id)[i];
+               if (!mptcp_rem_raddress(tcp_sk(sk)->mpcb, rem_id))
+                       mptcp_send_reset_rem_id(tcp_sk(sk)->mpcb, rem_id);
+       }
+}
+
+static void mptcp_parse_addropt(const struct sk_buff *skb, struct sock *sk)
+{
+       struct tcphdr *th = tcp_hdr(skb);
+       unsigned char *ptr;
+       int length = (th->doff * 4) - sizeof(struct tcphdr);
+
+       /* Jump through the options to check whether ADD_ADDR is there */
+       ptr = (unsigned char *)(th + 1);
+       while (length > 0) {
+               int opcode = *ptr++;
+               int opsize;
+
+               switch (opcode) {
+               case TCPOPT_EOL:
+                       return;
+               case TCPOPT_NOP:
+                       length--;
+                       continue;
+               default:
+                       opsize = *ptr++;
+                       if (opsize < 2)
+                               return;
+                       if (opsize > length)
+                               return;  /* don't parse partial options */
+                       if (opcode == TCPOPT_MPTCP &&
+                           ((struct mptcp_option *)ptr)->sub == MPTCP_SUB_ADD_ADDR) {
+#if IS_ENABLED(CONFIG_IPV6)
+                               struct mp_add_addr *mpadd = (struct mp_add_addr *)ptr;
+                               if ((mpadd->ipver == 4 && opsize != MPTCP_SUB_LEN_ADD_ADDR4 &&
+                                    opsize != MPTCP_SUB_LEN_ADD_ADDR4 + 2) ||
+                                   (mpadd->ipver == 6 && opsize != MPTCP_SUB_LEN_ADD_ADDR6 &&
+                                    opsize != MPTCP_SUB_LEN_ADD_ADDR6 + 2))
+#else
+                               if (opsize != MPTCP_SUB_LEN_ADD_ADDR4 &&
+                                   opsize != MPTCP_SUB_LEN_ADD_ADDR4 + 2)
+#endif /* CONFIG_IPV6 */
+                                       goto cont;
+
+                               mptcp_handle_add_addr(ptr, sk);
+                       }
+                       if (opcode == TCPOPT_MPTCP &&
+                           ((struct mptcp_option *)ptr)->sub == MPTCP_SUB_REMOVE_ADDR) {
+                               if ((opsize - MPTCP_SUB_LEN_REMOVE_ADDR) < 0)
+                                       goto cont;
+
+                               mptcp_handle_rem_addr(ptr, sk);
+                       }
+cont:
+                       ptr += opsize - 2;
+                       length -= opsize;
+               }
+       }
+       return;
+}
+
+static inline int mptcp_mp_fail_rcvd(struct sock *sk, const struct tcphdr *th)
+{
+       struct mptcp_tcp_sock *mptcp = tcp_sk(sk)->mptcp;
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct mptcp_cb *mpcb = tcp_sk(sk)->mpcb;
+
+       if (unlikely(mptcp->rx_opt.mp_fail)) {
+               mptcp->rx_opt.mp_fail = 0;
+
+               if (!th->rst && !mpcb->infinite_mapping_snd) {
+                       struct sock *sk_it;
+
+                       mpcb->send_infinite_mapping = 1;
+                       /* We resend everything that has not been acknowledged */
+                       meta_sk->sk_send_head = tcp_write_queue_head(meta_sk);
+
+                       /* We artificially restart the whole send-queue. Thus,
+                        * it is as if no packets are in flight
+                        */
+                       tcp_sk(meta_sk)->packets_out = 0;
+
+                       /* If the snd_nxt already wrapped around, we have to
+                        * undo the wrapping, as we are restarting from snd_una
+                        * on.
+                        */
+                       if (tcp_sk(meta_sk)->snd_nxt < tcp_sk(meta_sk)->snd_una) {
+                               mpcb->snd_high_order[mpcb->snd_hiseq_index] -= 2;
+                               mpcb->snd_hiseq_index = mpcb->snd_hiseq_index ? 0 : 1;
+                       }
+                       tcp_sk(meta_sk)->snd_nxt = tcp_sk(meta_sk)->snd_una;
+
+                       /* Trigger a sending on the meta. */
+                       mptcp_push_pending_frames(meta_sk);
+
+                       mptcp_for_each_sk(mpcb, sk_it) {
+                               if (sk != sk_it)
+                                       mptcp_sub_force_close(sk_it);
+                       }
+               }
+
+               return 0;
+       }
+
+       if (unlikely(mptcp->rx_opt.mp_fclose)) {
+               struct sock *sk_it, *tmpsk;
+
+               mptcp->rx_opt.mp_fclose = 0;
+               if (mptcp->rx_opt.mptcp_key != mpcb->mptcp_loc_key)
+                       return 0;
+
+               if (tcp_need_reset(sk->sk_state))
+                       tcp_send_active_reset(sk, GFP_ATOMIC);
+
+               mptcp_for_each_sk_safe(mpcb, sk_it, tmpsk)
+                       mptcp_sub_force_close(sk_it);
+
+               tcp_reset(meta_sk);
+
+               return 1;
+       }
+
+       return 0;
+}
+
+static inline void mptcp_path_array_check(struct sock *meta_sk)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+
+       if (unlikely(mpcb->list_rcvd)) {
+               mpcb->list_rcvd = 0;
+               if (mpcb->pm_ops->new_remote_address)
+                       mpcb->pm_ops->new_remote_address(meta_sk);
+       }
+}
+
+int mptcp_handle_options(struct sock *sk, const struct tcphdr *th, struct sk_buff *skb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct mptcp_options_received *mopt = &tp->mptcp->rx_opt;
+
+       if (tp->mpcb->infinite_mapping_rcv || tp->mpcb->infinite_mapping_snd)
+               return 0;
+
+       if (mptcp_mp_fail_rcvd(sk, th))
+               return 1;
+
+       /* RFC 6824, Section 3.3:
+        * If a checksum is not present when its use has been negotiated, the
+        * receiver MUST close the subflow with a RST as it is considered broken.
+        */
+       if (mptcp_is_data_seq(skb) && tp->mpcb->dss_csum &&
+           !(TCP_SKB_CB(skb)->mptcp_flags & MPTCPHDR_DSS_CSUM)) {
+               if (tcp_need_reset(sk->sk_state))
+                       tcp_send_active_reset(sk, GFP_ATOMIC);
+
+               mptcp_sub_force_close(sk);
+               return 1;
+       }
+
+       /* We have to acknowledge retransmissions of the third
+        * ack.
+        */
+       if (mopt->join_ack) {
+               tcp_send_delayed_ack(sk);
+               mopt->join_ack = 0;
+       }
+
+       if (mopt->saw_add_addr || mopt->saw_rem_addr) {
+               if (mopt->more_add_addr || mopt->more_rem_addr) {
+                       mptcp_parse_addropt(skb, sk);
+               } else {
+                       if (mopt->saw_add_addr)
+                               mptcp_handle_add_addr(mopt->add_addr_ptr, sk);
+                       if (mopt->saw_rem_addr)
+                               mptcp_handle_rem_addr(mopt->rem_addr_ptr, sk);
+               }
+
+               mopt->more_add_addr = 0;
+               mopt->saw_add_addr = 0;
+               mopt->more_rem_addr = 0;
+               mopt->saw_rem_addr = 0;
+       }
+       if (mopt->saw_low_prio) {
+               if (mopt->saw_low_prio == 1) {
+                       tp->mptcp->rcv_low_prio = mopt->low_prio;
+               } else {
+                       struct sock *sk_it;
+                       mptcp_for_each_sk(tp->mpcb, sk_it) {
+                               struct mptcp_tcp_sock *mptcp = tcp_sk(sk_it)->mptcp;
+                               if (mptcp->rem_id == mopt->prio_addr_id)
+                                       mptcp->rcv_low_prio = mopt->low_prio;
+                       }
+               }
+               mopt->saw_low_prio = 0;
+       }
+
+       mptcp_data_ack(sk, skb);
+
+       mptcp_path_array_check(mptcp_meta_sk(sk));
+       /* Socket may have been mp_killed by a REMOVE_ADDR */
+       if (tp->mp_killed)
+               return 1;
+
+       return 0;
+}
+
+/* The skptr is needed, because if we become MPTCP-capable, we have to switch
+ * from meta-socket to master-socket.
+ *
+ * @return: 1 - we want to reset this connection
+ *         2 - we want to discard the received syn/ack
+ *         0 - everything is fine - continue
+ */
+int mptcp_rcv_synsent_state_process(struct sock *sk, struct sock **skptr,
+                                   struct sk_buff *skb,
+                                   struct mptcp_options_received *mopt)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       if (tp->mpc) {
+               u8 hash_mac_check[20];
+               struct mptcp_cb *mpcb = tp->mpcb;
+
+               mptcp_hmac_sha1((u8 *)&mpcb->mptcp_rem_key,
+                               (u8 *)&mpcb->mptcp_loc_key,
+                               (u8 *)&tp->mptcp->rx_opt.mptcp_recv_nonce,
+                               (u8 *)&tp->mptcp->mptcp_loc_nonce,
+                               (u32 *)hash_mac_check);
+               if (memcmp(hash_mac_check,
+                          (char *)&tp->mptcp->rx_opt.mptcp_recv_tmac, 8)) {
+                       mptcp_sub_force_close(sk);
+                       return 1;
+               }
+
+               /* Set this flag in order to postpone data sending
+                * until the 4th ack arrives.
+                */
+               tp->mptcp->pre_established = 1;
+               tp->mptcp->rcv_low_prio = tp->mptcp->rx_opt.low_prio;
+
+               mptcp_hmac_sha1((u8 *)&mpcb->mptcp_loc_key,
+                               (u8 *)&mpcb->mptcp_rem_key,
+                               (u8 *)&tp->mptcp->mptcp_loc_nonce,
+                               (u8 *)&tp->mptcp->rx_opt.mptcp_recv_nonce,
+                               (u32 *)&tp->mptcp->sender_mac[0]);
+
+       } else if (mopt->saw_mpc) {
+               if (mptcp_create_master_sk(sk, mopt->mptcp_key,
+                                          ntohs(tcp_hdr(skb)->window)))
+                       return 2;
+
+               sk = tcp_sk(sk)->mpcb->master_sk;
+               *skptr = sk;
+               tp = tcp_sk(sk);
+
+               /* snd_nxt - 1, because it has been incremented
+                * by tcp_connect for the SYN
+                */
+               tp->mptcp->snt_isn = tp->snd_nxt - 1;
+               tp->mpcb->dss_csum = mopt->dss_csum;
+               tp->mptcp->include_mpc = 1;
+
+               sk_set_socket(sk, mptcp_meta_sk(sk)->sk_socket);
+               sk->sk_wq = mptcp_meta_sk(sk)->sk_wq;
+
+               mptcp_update_metasocket(sk, mptcp_meta_sk(sk));
+
+                /* hold in mptcp_inherit_sk due to initialization to 2 */
+               sock_put(sk);
+       } else {
+               tp->request_mptcp = 0;
+
+               if (tp->inside_tk_table)
+                       mptcp_hash_remove(tp);
+       }
+
+       if (tp->mpc)
+               tp->mptcp->rcv_isn = TCP_SKB_CB(skb)->seq;
+
+       return 0;
+}
+
+bool mptcp_should_expand_sndbuf(const struct sock *sk)
+{
+       struct sock *sk_it;
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       int cnt_backups = 0;
+       int backup_available = 0;
+
+       /* We circumvent this check in tcp_check_space, because we want to
+        * always call sk_write_space. So, we reproduce the check here.
+        */
+       if (!meta_sk->sk_socket ||
+           !test_bit(SOCK_NOSPACE, &meta_sk->sk_socket->flags))
+               return false;
+
+       /* If the user specified a specific send buffer setting, do
+        * not modify it.
+        */
+       if (meta_sk->sk_userlocks & SOCK_SNDBUF_LOCK)
+               return false;
+
+       /* If we are under global TCP memory pressure, do not expand.  */
+       if (sk_under_memory_pressure(meta_sk))
+               return false;
+
+       /* If we are under soft global TCP memory pressure, do not expand.  */
+       if (sk_memory_allocated(meta_sk) >= sk_prot_mem_limits(meta_sk, 0))
+               return false;
+
+
+       /* For MPTCP we look for a subsocket that could send data.
+        * If we found one, then we update the send-buffer.
+        */
+       mptcp_for_each_sk(meta_tp->mpcb, sk_it) {
+               struct tcp_sock *tp_it = tcp_sk(sk_it);
+
+               if (!mptcp_sk_can_send(sk_it))
+                       continue;
+
+               /* Backup-flows have to be counted - if there is no other
+                * subflow we take the backup-flow into account. */
+               if (tp_it->mptcp->rcv_low_prio || tp_it->mptcp->low_prio) {
+                       cnt_backups++;
+               }
+
+               if (tp_it->packets_out < tp_it->snd_cwnd) {
+                       if (tp_it->mptcp->rcv_low_prio || tp_it->mptcp->low_prio) {
+                               backup_available = 1;
+                               continue;
+                       }
+                       return true;
+               }
+       }
+
+       /* Backup-flow is available for sending - update send-buffer */
+       if (meta_tp->mpcb->cnt_established == cnt_backups && backup_available)
+               return true;
+       return false;
+}
+
+void mptcp_init_buffer_space(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       int space;
+
+       tcp_init_buffer_space(sk);
+
+       if (is_master_tp(tp)) {
+               /* If there is only one subflow, we just use regular TCP
+                * autotuning. User-locks are handled already by
+                * tcp_init_buffer_space
+                */
+               meta_tp->window_clamp = tp->window_clamp;
+               meta_tp->rcv_ssthresh = tp->rcv_ssthresh;
+               meta_sk->sk_rcvbuf = sk->sk_rcvbuf;
+               meta_sk->sk_sndbuf = sk->sk_sndbuf;
+
+               return;
+       }
+
+       if (meta_sk->sk_userlocks & SOCK_RCVBUF_LOCK)
+               goto snd_buf;
+
+       /* Adding a new subflow to the rcv-buffer space. We make a simple
+        * addition, to give some space to allow traffic on the new subflow. 
+        * Autotuning will increase it further later on.
+        */
+       space = min(meta_sk->sk_rcvbuf + sk->sk_rcvbuf, sysctl_tcp_rmem[2]);
+       if (space > meta_sk->sk_rcvbuf) {
+               meta_tp->window_clamp += tp->window_clamp;
+               meta_tp->rcv_ssthresh += tp->rcv_ssthresh;
+               meta_sk->sk_rcvbuf = space;
+       }
+
+snd_buf:
+       if (meta_sk->sk_userlocks & SOCK_SNDBUF_LOCK)
+               return;
+
+       /* Adding a new subflow to the send-buffer space. We make a simple
+        * addition, to give some space to allow traffic on the new subflow. 
+        * Autotuning will increase it further later on.
+        */
+       space = min(meta_sk->sk_sndbuf + sk->sk_sndbuf, sysctl_tcp_wmem[2]);
+       if (space > meta_sk->sk_sndbuf) {
+               meta_sk->sk_sndbuf = space;
+               meta_sk->sk_write_space(meta_sk);
+       }
+}
+
+void mptcp_tcp_set_rto(struct sock *sk)
+{
+       tcp_set_rto(sk);
+       mptcp_set_rto(sk);
+}
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_ipv4.c linux-3.14.45/net/mptcp/mptcp_ipv4.c
--- linux-3.14.45.orig/net/mptcp/mptcp_ipv4.c   1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_ipv4.c        2015-06-24 14:15:48.895862487 +0200
@@ -0,0 +1,603 @@
+/*
+ *     MPTCP implementation - IPv4-specific functions
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/export.h>
+#include <linux/ip.h>
+#include <linux/list.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/tcp.h>
+
+#include <net/inet_common.h>
+#include <net/inet_connection_sock.h>
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+#include <net/request_sock.h>
+#include <net/tcp.h>
+
+u32 mptcp_v4_get_nonce(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
+                      u32 seq)
+{
+       u32 hash[MD5_DIGEST_WORDS];
+
+       hash[0] = (__force u32)saddr;
+       hash[1] = (__force u32)daddr;
+       hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
+       hash[3] = seq;
+
+       md5_transform(hash, mptcp_secret);
+
+       return hash[0];
+}
+
+u64 mptcp_v4_get_key(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport)
+{
+       u32 hash[MD5_DIGEST_WORDS];
+
+       hash[0] = (__force u32)saddr;
+       hash[1] = (__force u32)daddr;
+       hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
+       hash[3] = mptcp_key_seed++;
+
+       md5_transform(hash, mptcp_secret);
+
+       return *((u64 *)hash);
+}
+
+
+static void mptcp_v4_reqsk_destructor(struct request_sock *req)
+{
+       mptcp_reqsk_destructor(req);
+
+       tcp_v4_reqsk_destructor(req);
+}
+
+/* Similar to tcp_request_sock_ops */
+struct request_sock_ops mptcp_request_sock_ops __read_mostly = {
+       .family         =       PF_INET,
+       .obj_size       =       sizeof(struct mptcp_request_sock),
+       .rtx_syn_ack    =       tcp_v4_rtx_synack,
+       .send_ack       =       tcp_v4_reqsk_send_ack,
+       .destructor     =       mptcp_v4_reqsk_destructor,
+       .send_reset     =       tcp_v4_send_reset,
+       .syn_ack_timeout =      tcp_syn_ack_timeout,
+};
+
+static void mptcp_v4_reqsk_queue_hash_add(struct sock *meta_sk,
+                                         struct request_sock *req,
+                                         unsigned long timeout)
+{
+       const u32 h1 = inet_synq_hash(inet_rsk(req)->ir_rmt_addr,
+                                    inet_rsk(req)->ir_rmt_port,
+                                    0, MPTCP_HASH_SIZE);
+       /* We cannot call inet_csk_reqsk_queue_hash_add(), because we do not
+        * want to reset the keepalive-timer (responsible for retransmitting
+        * SYN/ACKs). We do not retransmit SYN/ACKs+MP_JOINs, because we cannot
+        * overload the keepalive timer. Also, it's not a big deal, because the
+        * third ACK of the MP_JOIN-handshake is sent in a reliable manner. So,
+        * if the third ACK gets lost, the client will handle the retransmission
+        * anyways. If our SYN/ACK gets lost, the client will retransmit the
+        * SYN.
+        */ 
+       struct inet_connection_sock *meta_icsk = inet_csk(meta_sk);
+       struct listen_sock *lopt = meta_icsk->icsk_accept_queue.listen_opt;
+       const u32 h2 = inet_synq_hash(inet_rsk(req)->ir_rmt_addr,
+                                    inet_rsk(req)->ir_rmt_port,
+                                    lopt->hash_rnd, lopt->nr_table_entries);
+
+       reqsk_queue_hash_req(&meta_icsk->icsk_accept_queue, h2, req, timeout);
+       reqsk_queue_added(&meta_icsk->icsk_accept_queue);
+
+       spin_lock(&mptcp_reqsk_hlock);
+       list_add(&mptcp_rsk(req)->collide_tuple, &mptcp_reqsk_htb[h1]);
+       spin_unlock(&mptcp_reqsk_hlock);
+}
+
+/* Similar to tcp_v4_conn_request */
+static void mptcp_v4_join_request(struct sock *meta_sk, struct sk_buff *skb)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct tcp_options_received tmp_opt;
+       struct mptcp_options_received mopt;
+       struct request_sock *req;
+       struct inet_request_sock *ireq;
+       struct mptcp_request_sock *mtreq;
+       struct dst_entry *dst = NULL;
+       u8 mptcp_hash_mac[20];
+       __be32 saddr = ip_hdr(skb)->saddr;
+       __be32 daddr = ip_hdr(skb)->daddr;
+       __u32 isn = TCP_SKB_CB(skb)->when;
+       int want_cookie = 0;
+       union inet_addr addr;
+
+       tcp_clear_options(&tmp_opt);
+       mptcp_init_mp_opt(&mopt);
+       tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
+       tmp_opt.user_mss = tcp_sk(meta_sk)->rx_opt.user_mss;
+       tcp_parse_options(skb, &tmp_opt, &mopt, 0, NULL);
+
+       req = inet_reqsk_alloc(&mptcp_request_sock_ops);
+       if (!req)
+               return;
+
+#ifdef CONFIG_TCP_MD5SIG
+       tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
+#endif
+
+       tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
+       tcp_openreq_init(req, &tmp_opt, skb);
+
+       ireq = inet_rsk(req);
+       ireq->ir_loc_addr = daddr;
+       ireq->ir_rmt_addr = saddr;
+       ireq->no_srccheck = inet_sk(meta_sk)->transparent;
+       ireq->opt = tcp_v4_save_options(skb);
+
+       if (security_inet_conn_request(meta_sk, skb, req))
+               goto drop_and_free;
+
+       if (!want_cookie || tmp_opt.tstamp_ok)
+               TCP_ECN_create_request(req, skb, sock_net(meta_sk));
+
+       if (!isn) {
+               struct flowi4 fl4;
+
+               /* VJ's idea. We save last timestamp seen
+                * from the destination in peer table, when entering
+                * state TIME-WAIT, and check against it before
+                * accepting new connection request.
+                *
+                * If "isn" is not zero, this request hit alive
+                * timewait bucket, so that all the necessary checks
+                * are made in the function processing timewait state.
+                */
+               if (tmp_opt.saw_tstamp &&
+                   tcp_death_row.sysctl_tw_recycle &&
+                   (dst = inet_csk_route_req(meta_sk, &fl4, req)) != NULL &&
+                   fl4.daddr == saddr) {
+                       if (!tcp_peer_is_proven(req, dst, true)) {
+                               NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_PAWSPASSIVEREJECTED);
+                               goto drop_and_release;
+                       }
+               }
+               /* Kill the following clause, if you dislike this way. */
+               else if (!sysctl_tcp_syncookies &&
+                        (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(meta_sk) <
+                         (sysctl_max_syn_backlog >> 2)) &&
+                        !tcp_peer_is_proven(req, dst, false)) {
+                       /* Without syncookies last quarter of
+                        * backlog is filled with destinations,
+                        * proven to be alive.
+                        * It means that we continue to communicate
+                        * to destinations, already remembered
+                        * to the moment of synflood.
+                        */
+                       LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("drop open request from %pI4/%u\n"),
+                                      &saddr, ntohs(tcp_hdr(skb)->source));
+                       goto drop_and_release;
+               }
+
+               isn = tcp_v4_init_sequence(skb);
+       }
+       tcp_rsk(req)->snt_isn = isn;
+       tcp_rsk(req)->snt_synack = tcp_time_stamp;
+       tcp_rsk(req)->listener = NULL;
+
+       mtreq = mptcp_rsk(req);
+       mtreq->mpcb = mpcb;
+       INIT_LIST_HEAD(&mtreq->collide_tuple);
+       mtreq->mptcp_rem_nonce = mopt.mptcp_recv_nonce;
+       mtreq->mptcp_rem_key = mpcb->mptcp_rem_key;
+       mtreq->mptcp_loc_key = mpcb->mptcp_loc_key;
+       mtreq->mptcp_loc_nonce = mptcp_v4_get_nonce(saddr, daddr,
+                                                   tcp_hdr(skb)->source,
+                                                   tcp_hdr(skb)->dest, isn);
+       mptcp_hmac_sha1((u8 *)&mtreq->mptcp_loc_key,
+                       (u8 *)&mtreq->mptcp_rem_key,
+                       (u8 *)&mtreq->mptcp_loc_nonce,
+                       (u8 *)&mtreq->mptcp_rem_nonce, (u32 *)mptcp_hash_mac);
+       mtreq->mptcp_hash_tmac = *(u64 *)mptcp_hash_mac;
+
+       addr.ip = ireq->ir_loc_addr;
+       mtreq->loc_id = mpcb->pm_ops->get_local_id(AF_INET, &addr, sock_net(meta_sk));
+       if (mtreq->loc_id == -1) /* Address not part of the allowed ones */
+               goto drop_and_release;
+       mtreq->rem_id = mopt.rem_id;
+       mtreq->low_prio = mopt.low_prio;
+       tcp_rsk(req)->saw_mpc = 1;
+
+       if (tcp_v4_send_synack(meta_sk, dst, req, skb_get_queue_mapping(skb)))
+               goto drop_and_free;
+
+       /* Adding to request queue in metasocket */
+       mptcp_v4_reqsk_queue_hash_add(meta_sk, req, TCP_TIMEOUT_INIT);
+
+       return;
+
+drop_and_release:
+       dst_release(dst);
+drop_and_free:
+       reqsk_free(req);
+       return;
+}
+
+int mptcp_v4_rem_raddress(struct mptcp_cb *mpcb, u8 id)
+{
+       int i;
+
+       for (i = 0; i < MPTCP_MAX_ADDR; i++) {
+               if (!((1 << i) & mpcb->rem4_bits))
+                       continue;
+
+               if (mpcb->remaddr4[i].rem4_id == id) {
+                       /* remove address from bitfield */
+                       mpcb->rem4_bits &= ~(1 << i);
+
+                       return 0;
+               }
+       }
+
+       return -1;
+}
+
+/* Based on function tcp_v4_conn_request (tcp_ipv4.c)
+ * Returns -1 if there is no space anymore to store an additional
+ * address
+ */
+int mptcp_v4_add_raddress(struct mptcp_cb *mpcb, const struct in_addr *addr,
+                         __be16 port, u8 id)
+{
+       int i;
+       struct mptcp_rem4 *rem4;
+
+       mptcp_for_each_bit_set(mpcb->rem4_bits, i) {
+               rem4 = &mpcb->remaddr4[i];
+
+               /* Address is already in the list --- continue */
+               if (rem4->rem4_id == id &&
+                   rem4->addr.s_addr == addr->s_addr && rem4->port == port)
+                       return 0;
+
+               /* This may be the case, when the peer is behind a NAT. He is
+                * trying to JOIN, thus sending the JOIN with a certain ID.
+                * However the src_addr of the IP-packet has been changed. We
+                * update the addr in the list, because this is the address as
+                * OUR BOX sees it.
+                */
+               if (rem4->rem4_id == id && rem4->addr.s_addr != addr->s_addr) {
+                       /* update the address */
+                       mptcp_debug("%s: updating old addr:%pI4 to addr %pI4 with id:%d\n",
+                                   __func__, &rem4->addr.s_addr,
+                                   &addr->s_addr, id);
+                       rem4->addr.s_addr = addr->s_addr;
+                       rem4->port = port;
+                       mpcb->list_rcvd = 1;
+                       return 0;
+               }
+       }
+
+       i = mptcp_find_free_index(mpcb->rem4_bits);
+       /* Do we have already the maximum number of local/remote addresses? */
+       if (i < 0) {
+               mptcp_debug("%s: At max num of remote addresses: %d --- not adding address: %pI4\n",
+                           __func__, MPTCP_MAX_ADDR, &addr->s_addr);
+               return -1;
+       }
+
+       rem4 = &mpcb->remaddr4[i];
+
+       /* Address is not known yet, store it */
+       rem4->addr.s_addr = addr->s_addr;
+       rem4->port = port;
+       rem4->bitfield = 0;
+       rem4->retry_bitfield = 0;
+       rem4->rem4_id = id;
+       mpcb->list_rcvd = 1;
+       mpcb->rem4_bits |= (1 << i);
+
+       return 0;
+}
+
+/* Sets the bitfield of the remote-address field
+ * local address is not set as it will disappear with the global address-list
+ */
+void mptcp_v4_set_init_addr_bit(struct mptcp_cb *mpcb, __be32 daddr, int index)
+{
+       int i;
+
+       mptcp_for_each_bit_set(mpcb->rem4_bits, i) {
+               if (mpcb->remaddr4[i].addr.s_addr == daddr) {
+                       mpcb->remaddr4[i].bitfield |= (1 << index);
+                       return;
+               }
+       }
+}
+
+/* We only process join requests here. (either the SYN or the final ACK) */
+int mptcp_v4_do_rcv(struct sock *meta_sk, struct sk_buff *skb)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct sock *child, *rsk = NULL;
+       int ret;
+
+       if (!(TCP_SKB_CB(skb)->mptcp_flags & MPTCPHDR_JOIN)) {
+               struct tcphdr *th = tcp_hdr(skb);
+               const struct iphdr *iph = ip_hdr(skb);
+               struct sock *sk;
+
+               sk = inet_lookup_established(sock_net(meta_sk), &tcp_hashinfo,
+                                            iph->saddr, th->source, iph->daddr,
+                                            th->dest, inet_iif(skb));
+
+               if (!sk) {
+                       kfree_skb(skb);
+                       return 0;
+               }
+               if (is_meta_sk(sk)) {
+                       WARN("%s Did not find a sub-sk - did found the meta!\n", __func__);
+                       kfree_skb(skb);
+                       sock_put(sk);
+                       return 0;
+               }
+
+               if (sk->sk_state == TCP_TIME_WAIT) {
+                       inet_twsk_put(inet_twsk(sk));
+                       kfree_skb(skb);
+                       return 0;
+               }
+
+               ret = tcp_v4_do_rcv(sk, skb);
+               sock_put(sk);
+
+               return ret;
+       }
+       TCP_SKB_CB(skb)->mptcp_flags = 0;
+
+       /* Has been removed from the tk-table. Thus, no new subflows.
+        *
+        * Check for close-state is necessary, because we may have been closed
+        * without passing by mptcp_close().
+        *
+        * When falling back, no new subflows are allowed either.
+        */
+       if (meta_sk->sk_state == TCP_CLOSE || !tcp_sk(meta_sk)->inside_tk_table ||
+           mpcb->infinite_mapping_rcv || mpcb->send_infinite_mapping)
+               goto reset_and_discard;
+
+       child = tcp_v4_hnd_req(meta_sk, skb);
+
+       if (!child)
+               goto discard;
+
+       if (child != meta_sk) {
+               sock_rps_save_rxhash(child, skb);
+               /* We don't call tcp_child_process here, because we hold
+                * already the meta-sk-lock and are sure that it is not owned
+                * by the user.
+                */
+               ret = tcp_rcv_state_process(child, skb, tcp_hdr(skb), skb->len);
+               bh_unlock_sock(child);
+               sock_put(child);
+               if (ret) {
+                       rsk = child;
+                       goto reset_and_discard;
+               }
+       } else {
+               if (tcp_hdr(skb)->syn) {
+                       struct mp_join *join_opt = mptcp_find_join(skb);
+                       /* Currently we make two calls to mptcp_find_join(). This
+                        * can probably be optimized.
+                        */
+                       if (mptcp_v4_add_raddress(mpcb,
+                                                 (struct in_addr *)&ip_hdr(skb)->saddr,
+                                                 0,
+                                                 join_opt->addr_id) < 0)
+                               goto reset_and_discard;
+                       mpcb->list_rcvd = 0;
+
+                       mptcp_v4_join_request(meta_sk, skb);
+                       goto discard;
+               }
+               goto reset_and_discard;
+       }
+       return 0;
+
+reset_and_discard:
+       tcp_v4_send_reset(rsk, skb);
+discard:
+       kfree_skb(skb);
+       return 0;
+}
+
+/* After this, the ref count of the meta_sk associated with the request_sock
+ * is incremented. Thus it is the responsibility of the caller
+ * to call sock_put() when the reference is not needed anymore.
+ */
+struct sock *mptcp_v4_search_req(const __be16 rport, const __be32 raddr,
+                                const __be32 laddr, const struct net *net)
+{
+       struct mptcp_request_sock *mtreq;
+       struct sock *meta_sk = NULL;
+
+       spin_lock(&mptcp_reqsk_hlock);
+       list_for_each_entry(mtreq,
+                           &mptcp_reqsk_htb[inet_synq_hash(raddr, rport, 0,
+                                                           MPTCP_HASH_SIZE)],
+                           collide_tuple) {
+               struct inet_request_sock *ireq = inet_rsk(rev_mptcp_rsk(mtreq));
+               meta_sk = mtreq->mpcb->meta_sk;
+
+               if (ireq->ir_rmt_port == rport &&
+                   ireq->ir_rmt_addr == raddr &&
+                   ireq->ir_loc_addr == laddr &&
+                   rev_mptcp_rsk(mtreq)->rsk_ops->family == AF_INET &&
+                   net_eq(net, sock_net(meta_sk)))
+                       break;
+               meta_sk = NULL;
+       }
+
+       if (meta_sk && unlikely(!atomic_inc_not_zero(&meta_sk->sk_refcnt)))
+               meta_sk = NULL;
+       spin_unlock(&mptcp_reqsk_hlock);
+
+       return meta_sk;
+}
+
+/* Create a new IPv4 subflow.
+ *
+ * We are in user-context and meta-sock-lock is hold.
+ */
+int mptcp_init4_subsockets(struct sock *meta_sk, const struct mptcp_loc4 *loc,
+                          struct mptcp_rem4 *rem)
+{
+       struct tcp_sock *tp;
+       struct sock *sk;
+       struct sockaddr_in loc_in, rem_in;
+       struct socket sock;
+       int ulid_size = 0, ret;
+
+       /** First, create and prepare the new socket */
+
+       sock.type = meta_sk->sk_socket->type;
+       sock.state = SS_UNCONNECTED;
+       sock.wq = meta_sk->sk_socket->wq;
+       sock.file = meta_sk->sk_socket->file;
+       sock.ops = NULL;
+
+       ret = inet_create(sock_net(meta_sk), &sock, IPPROTO_TCP, 1);
+       if (unlikely(ret < 0)) {
+               mptcp_debug("%s inet_create failed ret: %d\n", __func__, ret);
+               return ret;
+       }
+
+       sk = sock.sk;
+       tp = tcp_sk(sk);
+
+       /* All subsockets need the MPTCP-lock-class */
+       lockdep_set_class_and_name(&(sk)->sk_lock.slock, &meta_slock_key, "slock-AF_INET-MPTCP");
+       lockdep_init_map(&(sk)->sk_lock.dep_map, "sk_lock-AF_INET-MPTCP", &meta_key, 0);
+
+       if (mptcp_add_sock(meta_sk, sk, loc->loc4_id, rem->rem4_id, GFP_KERNEL))
+               goto error;
+
+       tp->mptcp->slave_sk = 1;
+       tp->mptcp->low_prio = loc->low_prio;
+
+       /* Initializing the timer for an MPTCP subflow */
+       setup_timer(&tp->mptcp->mptcp_ack_timer, mptcp_ack_handler, (unsigned long)sk);
+
+       /** Then, connect the socket to the peer */
+
+       ulid_size = sizeof(struct sockaddr_in);
+       loc_in.sin_family = AF_INET;
+       rem_in.sin_family = AF_INET;
+       loc_in.sin_port = 0;
+       if (rem->port)
+               rem_in.sin_port = rem->port;
+       else
+               rem_in.sin_port = inet_sk(meta_sk)->inet_dport;
+       loc_in.sin_addr = loc->addr;
+       rem_in.sin_addr = rem->addr;
+
+       ret = sock.ops->bind(&sock, (struct sockaddr *)&loc_in, ulid_size);
+       if (ret < 0) {
+               mptcp_debug("%s: MPTCP subsocket bind() failed, error %d\n",
+                           __func__, ret);
+               goto error;
+       }
+
+       mptcp_debug("%s: token %#x pi %d src_addr:%pI4:%d dst_addr:%pI4:%d\n",
+                   __func__, tcp_sk(meta_sk)->mpcb->mptcp_loc_token,
+                   tp->mptcp->path_index, &loc_in.sin_addr,
+                   ntohs(loc_in.sin_port), &rem_in.sin_addr,
+                   ntohs(rem_in.sin_port));
+
+       ret = sock.ops->connect(&sock, (struct sockaddr *)&rem_in,
+                               ulid_size, O_NONBLOCK);
+       if (ret < 0 && ret != -EINPROGRESS) {
+               mptcp_debug("%s: MPTCP subsocket connect() failed, error %d\n",
+                           __func__, ret);
+               goto error;
+       }
+
+       sk_set_socket(sk, meta_sk->sk_socket);
+       sk->sk_wq = meta_sk->sk_wq;
+
+       return 0;
+
+error:
+       /* May happen if mptcp_add_sock fails first */
+       if (!tp->mpc) {
+               tcp_close(sk, 0);
+       } else {
+               local_bh_disable();
+               mptcp_sub_force_close(sk);
+               local_bh_enable();
+       }
+       return ret;
+}
+EXPORT_SYMBOL(mptcp_init4_subsockets);
+
+/* General initialization of IPv4 for MPTCP */
+int mptcp_pm_v4_init(void)
+{
+       int ret = 0;
+       struct request_sock_ops *ops = &mptcp_request_sock_ops;
+
+       ops->slab_name = kasprintf(GFP_KERNEL, "request_sock_%s", "MPTCP");
+       if (ops->slab_name == NULL) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       ops->slab = kmem_cache_create(ops->slab_name, ops->obj_size, 0,
+                                     SLAB_DESTROY_BY_RCU|SLAB_HWCACHE_ALIGN,
+                                     NULL);
+
+       if (ops->slab == NULL) {
+               ret =  -ENOMEM;
+               goto err_reqsk_create;
+       }
+
+out:
+       return ret;
+
+err_reqsk_create:
+       kfree(ops->slab_name);
+       ops->slab_name = NULL;
+       goto out;
+}
+
+void mptcp_pm_v4_undo(void)
+{
+       kmem_cache_destroy(mptcp_request_sock_ops.slab);
+       kfree(mptcp_request_sock_ops.slab_name);
+}
+
+
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_ipv6.c linux-3.14.45/net/mptcp/mptcp_ipv6.c
--- linux-3.14.45.orig/net/mptcp/mptcp_ipv6.c   1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_ipv6.c        2015-06-24 14:15:48.931862523 +0200
@@ -0,0 +1,822 @@
+/*
+ *     MPTCP implementation - IPv6-specific functions
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/export.h>
+#include <linux/in6.h>
+#include <linux/kernel.h>
+
+#include <net/addrconf.h>
+#include <net/flow.h>
+#include <net/inet6_connection_sock.h>
+#include <net/inet6_hashtables.h>
+#include <net/inet_common.h>
+#include <net/ipv6.h>
+#include <net/ip6_checksum.h>
+#include <net/ip6_route.h>
+#include <net/mptcp.h>
+#include <net/mptcp_v6.h>
+#include <net/tcp.h>
+#include <net/transp_v6.h>
+
+static int mptcp_v6v4_send_synack(struct sock *meta_sk, struct request_sock *req,
+                                 u16 queue_mapping);
+
+__u32 mptcp_v6_get_nonce(const __be32 *saddr, const __be32 *daddr,
+                        __be16 sport, __be16 dport, u32 seq)
+{
+       u32 secret[MD5_MESSAGE_BYTES / 4];
+       u32 hash[MD5_DIGEST_WORDS];
+       u32 i;
+
+       memcpy(hash, saddr, 16);
+       for (i = 0; i < 4; i++)
+               secret[i] = mptcp_secret[i] + (__force u32)daddr[i];
+       secret[4] = mptcp_secret[4] +
+                   (((__force u16)sport << 16) + (__force u16)dport);
+       secret[5] = seq;
+       for (i = 6; i < MD5_MESSAGE_BYTES / 4; i++)
+               secret[i] = mptcp_secret[i];
+
+       md5_transform(hash, secret);
+
+       return hash[0];
+}
+
+u64 mptcp_v6_get_key(const __be32 *saddr, const __be32 *daddr,
+                    __be16 sport, __be16 dport)
+{
+       u32 secret[MD5_MESSAGE_BYTES / 4];
+       u32 hash[MD5_DIGEST_WORDS];
+       u32 i;
+
+       memcpy(hash, saddr, 16);
+       for (i = 0; i < 4; i++)
+               secret[i] = mptcp_secret[i] + (__force u32)daddr[i];
+       secret[4] = mptcp_secret[4] +
+                   (((__force u16)sport << 16) + (__force u16)dport);
+       secret[5] = mptcp_key_seed++;
+       for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
+               secret[i] = mptcp_secret[i];
+
+       md5_transform(hash, secret);
+
+       return *((u64 *)hash);
+}
+
+static void mptcp_v6_reqsk_destructor(struct request_sock *req)
+{
+       mptcp_reqsk_destructor(req);
+
+       tcp_v6_reqsk_destructor(req);
+}
+
+/* Similar to tcp_v6_rtx_synack */
+static int mptcp_v6_rtx_synack(struct sock *meta_sk, struct request_sock *req)
+{
+       if (meta_sk->sk_family == AF_INET6)
+               return tcp_v6_rtx_synack(meta_sk, req);
+
+       TCP_INC_STATS_BH(sock_net(meta_sk), TCP_MIB_RETRANSSEGS);
+       return mptcp_v6v4_send_synack(meta_sk, req, 0);
+}
+
+/* Similar to tcp6_request_sock_ops */
+struct request_sock_ops mptcp6_request_sock_ops __read_mostly = {
+       .family         =       AF_INET6,
+       .obj_size       =       sizeof(struct mptcp_request_sock),
+       .rtx_syn_ack    =       mptcp_v6_rtx_synack,
+       .send_ack       =       tcp_v6_reqsk_send_ack,
+       .destructor     =       mptcp_v6_reqsk_destructor,
+       .send_reset     =       tcp_v6_send_reset,
+       .syn_ack_timeout =      tcp_syn_ack_timeout,
+};
+
+static void mptcp_v6_reqsk_queue_hash_add(struct sock *meta_sk,
+                                         struct request_sock *req,
+                                         unsigned long timeout)
+{
+       const u32 h1 = inet6_synq_hash(&inet_rsk(req)->ir_v6_rmt_addr,
+                                     inet_rsk(req)->ir_rmt_port,
+                                     0, MPTCP_HASH_SIZE);
+       /* We cannot call inet6_csk_reqsk_queue_hash_add(), because we do not
+        * want to reset the keepalive-timer (responsible for retransmitting
+        * SYN/ACKs). We do not retransmit SYN/ACKs+MP_JOINs, because we cannot
+        * overload the keepalive timer. Also, it's not a big deal, because the
+        * third ACK of the MP_JOIN-handshake is sent in a reliable manner. So,
+        * if the third ACK gets lost, the client will handle the retransmission
+        * anyways. If our SYN/ACK gets lost, the client will retransmit the
+        * SYN.
+        */ 
+       struct inet_connection_sock *meta_icsk = inet_csk(meta_sk);
+       struct listen_sock *lopt = meta_icsk->icsk_accept_queue.listen_opt;
+       const u32 h2 = inet6_synq_hash(&inet_rsk(req)->ir_v6_rmt_addr,
+                                     inet_rsk(req)->ir_rmt_port,
+                                     lopt->hash_rnd, lopt->nr_table_entries);
+
+       reqsk_queue_hash_req(&meta_icsk->icsk_accept_queue, h2, req, timeout);
+       reqsk_queue_added(&meta_icsk->icsk_accept_queue);
+
+       spin_lock(&mptcp_reqsk_hlock);
+       list_add(&mptcp_rsk(req)->collide_tuple, &mptcp_reqsk_htb[h1]);
+       spin_unlock(&mptcp_reqsk_hlock);
+}
+
+/* Similar to tcp_v6_send_synack
+ *
+ * The meta-socket is IPv4, but a new subsocket is IPv6
+ */
+static int mptcp_v6v4_send_synack(struct sock *meta_sk, struct request_sock *req,
+                                 u16 queue_mapping)
+{
+       struct inet_request_sock *treq = inet_rsk(req);
+       struct sk_buff *skb;
+       struct flowi6 fl6;
+       struct dst_entry *dst;
+       int err = -ENOMEM;
+
+       memset(&fl6, 0, sizeof(fl6));
+       fl6.flowi6_proto = IPPROTO_TCP;
+       fl6.daddr = treq->ir_v6_rmt_addr;
+       fl6.saddr = treq->ir_v6_loc_addr;
+       fl6.flowlabel = 0;
+       fl6.flowi6_oif = treq->ir_iif;
+       fl6.flowi6_mark = meta_sk->sk_mark;
+       fl6.fl6_dport = inet_rsk(req)->ir_rmt_port;
+       fl6.fl6_sport = htons(inet_rsk(req)->ir_num);
+       security_req_classify_flow(req, flowi6_to_flowi(&fl6));
+
+       dst = ip6_dst_lookup_flow(meta_sk, &fl6, NULL);
+       if (IS_ERR(dst)) {
+               err = PTR_ERR(dst);
+               return err;
+       }
+       skb = tcp_make_synack(meta_sk, dst, req, NULL);
+
+       if (skb) {
+               __tcp_v6_send_check(skb, &treq->ir_v6_loc_addr,
+                                   &treq->ir_v6_rmt_addr);
+
+               fl6.daddr = treq->ir_v6_rmt_addr;
+               skb_set_queue_mapping(skb, queue_mapping);
+               err = ip6_xmit(meta_sk, skb, &fl6, NULL, 0);
+               err = net_xmit_eval(err);
+       }
+
+       return err;
+}
+
+/* Similar to tcp_v6_syn_recv_sock
+ *
+ * The meta-socket is IPv4, but a new subsocket is IPv6
+ */
+struct sock *mptcp_v6v4_syn_recv_sock(struct sock *meta_sk, struct sk_buff *skb,
+                                     struct request_sock *req,
+                                     struct dst_entry *dst)
+{
+       struct inet_request_sock *treq;
+       struct ipv6_pinfo *newnp;
+       struct tcp6_sock *newtcp6sk;
+       struct inet_sock *newinet;
+       struct tcp_sock *newtp;
+       struct sock *newsk;
+
+       treq = inet_rsk(req);
+
+       if (sk_acceptq_is_full(meta_sk))
+               goto out_overflow;
+
+       if (!dst) {
+               /* This code is similar to inet6_csk_route_req, but as we
+                * don't have a np-pointer in the meta, we have to do it
+                * manually.
+                */
+               struct flowi6 fl6;
+
+               memset(&fl6, 0, sizeof(fl6));
+               fl6.flowi6_proto = IPPROTO_TCP;
+               fl6.daddr = treq->ir_v6_rmt_addr;
+               fl6.saddr = treq->ir_v6_loc_addr;
+               fl6.flowi6_oif = treq->ir_iif;
+               fl6.flowi6_mark = meta_sk->sk_mark;
+               fl6.fl6_dport = inet_rsk(req)->ir_rmt_port;
+               fl6.fl6_sport = htons(inet_rsk(req)->ir_num);
+               security_req_classify_flow(req, flowi6_to_flowi(&fl6));
+
+               dst = ip6_dst_lookup_flow(meta_sk, &fl6, NULL);
+               if (IS_ERR(dst))
+                       goto out;
+       }
+
+       newsk = tcp_create_openreq_child(meta_sk, req, skb);
+       if (newsk == NULL)
+               goto out_nonewsk;
+
+       /* Diff to tcp_v6_syn_recv_sock: Must do this prior to __ip6_dst_store,
+        * as it tries to access the pinet6-pointer.
+        */
+       newtcp6sk = (struct tcp6_sock *)newsk;
+       inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;
+
+       /*
+        * No need to charge this sock to the relevant IPv6 refcnt debug socks
+        * count here, tcp_create_openreq_child now does this for us, see the
+        * comment in that function for the gory details. -acme
+        */
+
+       newsk->sk_gso_type = SKB_GSO_TCPV6;
+       __ip6_dst_store(newsk, dst, NULL, NULL);
+       inet6_sk_rx_dst_set(newsk, skb);
+
+       newtp = tcp_sk(newsk);
+       newinet = inet_sk(newsk);
+       newnp = inet6_sk(newsk);
+
+       newsk->sk_v6_daddr = treq->ir_v6_rmt_addr;
+       newnp->saddr = treq->ir_v6_loc_addr;
+       newsk->sk_v6_rcv_saddr = treq->ir_v6_loc_addr;
+       newsk->sk_bound_dev_if = treq->ir_iif;
+
+       /* Now IPv6 options...
+
+          First: no IPv4 options.
+        */
+       newinet->inet_opt = NULL;
+       newnp->ipv6_ac_list = NULL;
+       newnp->ipv6_fl_list = NULL;
+       newnp->rxopt.all = 0;
+
+       /* Clone pktoptions received with SYN */
+       newnp->pktoptions = NULL;
+       if (treq->pktopts != NULL) {
+               newnp->pktoptions = skb_clone(treq->pktopts,
+                                             sk_gfp_atomic(meta_sk, GFP_ATOMIC));
+               consume_skb(treq->pktopts);
+               treq->pktopts = NULL;
+               if (newnp->pktoptions)
+                       skb_set_owner_r(newnp->pktoptions, newsk);
+       }
+       newnp->opt        = NULL;
+       newnp->mcast_oif  = inet6_iif(skb);
+       newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
+       newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
+
+       /* Initialization copied from inet6_create - normally this should have
+        * been handled by the memcpy as in tcp_v6_syn_recv_sock
+        */
+       newnp->hop_limit  = -1;
+       newnp->mc_loop    = 1;
+       newnp->pmtudisc   = IPV6_PMTUDISC_WANT;
+       (void)xchg(&newnp->rxpmtu, NULL);
+
+       inet_csk(newsk)->icsk_ext_hdr_len = 0;
+
+       tcp_mtup_init(newsk);
+       tcp_sync_mss(newsk, dst_mtu(dst));
+       newtp->advmss = dst_metric_advmss(dst);
+       if (tcp_sk(meta_sk)->rx_opt.user_mss &&
+           tcp_sk(meta_sk)->rx_opt.user_mss < newtp->advmss)
+               newtp->advmss = tcp_sk(meta_sk)->rx_opt.user_mss;
+
+       tcp_initialize_rcv_mss(newsk);
+
+       newinet->inet_daddr = LOOPBACK4_IPV6;
+       newinet->inet_saddr = LOOPBACK4_IPV6;
+       newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
+
+       if (__inet_inherit_port(meta_sk, newsk) < 0) {
+               inet_csk_prepare_forced_close(newsk);
+               tcp_done(newsk);
+               goto out;
+       }
+       __inet6_hash(newsk, NULL);
+
+       return newsk;
+
+out_overflow:
+       NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_LISTENOVERFLOWS);
+out_nonewsk:
+       dst_release(dst);
+out:
+       NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_LISTENDROPS);
+       return NULL;
+}
+
+/* Similar to tcp_v6_conn_request */
+static void mptcp_v6_join_request(struct sock *meta_sk, struct sk_buff *skb)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct tcp_options_received tmp_opt;
+       struct mptcp_options_received mopt;
+       struct ipv6_pinfo *np = inet6_sk(meta_sk);
+       struct request_sock *req;
+       struct inet_request_sock *treq;
+       struct mptcp_request_sock *mtreq;
+       u8 mptcp_hash_mac[20];
+       __u32 isn = TCP_SKB_CB(skb)->when;
+       struct dst_entry *dst = NULL;
+       struct flowi6 fl6;
+       int want_cookie = 0;
+       union inet_addr addr;
+
+       tcp_clear_options(&tmp_opt);
+       mptcp_init_mp_opt(&mopt);
+       tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
+       tmp_opt.user_mss  = tcp_sk(meta_sk)->rx_opt.user_mss;
+       tcp_parse_options(skb, &tmp_opt, &mopt, 0, NULL);
+
+       req = inet6_reqsk_alloc(&mptcp6_request_sock_ops);
+       if (!req)
+               return;
+
+#ifdef CONFIG_TCP_MD5SIG
+       tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
+#endif
+
+       tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
+       tcp_openreq_init(req, &tmp_opt, skb);
+
+       treq = inet_rsk(req);
+       treq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
+       treq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
+
+       if (!want_cookie || tmp_opt.tstamp_ok)
+               TCP_ECN_create_request(req, skb, sock_net(meta_sk));
+
+       treq->ir_iif = meta_sk->sk_bound_dev_if;
+
+       /* So that link locals have meaning */
+       if (!meta_sk->sk_bound_dev_if &&
+           ipv6_addr_type(&treq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
+               treq->ir_iif = inet6_iif(skb);
+
+       if (!isn) {
+               if (meta_sk->sk_family == AF_INET6 &&
+                   (ipv6_opt_accepted(meta_sk, skb) ||
+                   np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
+                   np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)) {
+                       atomic_inc(&skb->users);
+                       treq->pktopts = skb;
+               }
+
+               /* VJ's idea. We save last timestamp seen
+                * from the destination in peer table, when entering
+                * state TIME-WAIT, and check against it before
+                * accepting new connection request.
+                *
+                * If "isn" is not zero, this request hit alive
+                * timewait bucket, so that all the necessary checks
+                * are made in the function processing timewait state.
+                */
+               if (tmp_opt.saw_tstamp &&
+                   tcp_death_row.sysctl_tw_recycle &&
+                   (dst = inet6_csk_route_req(meta_sk, &fl6, req)) != NULL) {
+                       if (!tcp_peer_is_proven(req, dst, true)) {
+                               NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_PAWSPASSIVEREJECTED);
+                               goto drop_and_release;
+                       }
+               }
+               /* Kill the following clause, if you dislike this way. */
+               else if (!sysctl_tcp_syncookies &&
+                        (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(meta_sk) <
+                         (sysctl_max_syn_backlog >> 2)) &&
+                        !tcp_peer_is_proven(req, dst, false)) {
+                       /* Without syncookies last quarter of
+                        * backlog is filled with destinations,
+                        * proven to be alive.
+                        * It means that we continue to communicate
+                        * to destinations, already remembered
+                        * to the moment of synflood.
+                        */
+                       LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI6/%u\n",
+                                      &treq->ir_v6_rmt_addr,
+                                      ntohs(tcp_hdr(skb)->source));
+                       goto drop_and_release;
+               }
+
+               isn = tcp_v6_init_sequence(skb);
+       }
+
+       tcp_rsk(req)->snt_isn = isn;
+       tcp_rsk(req)->snt_synack = tcp_time_stamp;
+       tcp_rsk(req)->listener = NULL;
+
+       mtreq = mptcp_rsk(req);
+       mtreq->mpcb = mpcb;
+       INIT_LIST_HEAD(&mtreq->collide_tuple);
+       mtreq->mptcp_rem_nonce = mopt.mptcp_recv_nonce;
+       mtreq->mptcp_rem_key = mpcb->mptcp_rem_key;
+       mtreq->mptcp_loc_key = mpcb->mptcp_loc_key;
+       mtreq->mptcp_loc_nonce = mptcp_v6_get_nonce(ipv6_hdr(skb)->daddr.s6_addr32,
+                                                   ipv6_hdr(skb)->saddr.s6_addr32,
+                                                   tcp_hdr(skb)->dest,
+                                                   tcp_hdr(skb)->source, isn);
+       mptcp_hmac_sha1((u8 *)&mtreq->mptcp_loc_key,
+                       (u8 *)&mtreq->mptcp_rem_key,
+                       (u8 *)&mtreq->mptcp_loc_nonce,
+                       (u8 *)&mtreq->mptcp_rem_nonce, (u32 *)mptcp_hash_mac);
+       mtreq->mptcp_hash_tmac = *(u64 *)mptcp_hash_mac;
+
+       addr.in6 = treq->ir_v6_loc_addr;
+       mtreq->loc_id = mpcb->pm_ops->get_local_id(AF_INET6, &addr, sock_net(meta_sk));
+       if (mtreq->loc_id == -1) /* Address not part of the allowed ones */
+               goto drop_and_release;
+       mtreq->rem_id = mopt.rem_id;
+       mtreq->low_prio = mopt.low_prio;
+       tcp_rsk(req)->saw_mpc = 1;
+
+       if (meta_sk->sk_family == AF_INET6) {
+               if (tcp_v6_send_synack(meta_sk, dst, &fl6, req,
+                                      skb_get_queue_mapping(skb)))
+                       goto drop_and_free;
+       } else {
+               if (mptcp_v6v4_send_synack(meta_sk, req, skb_get_queue_mapping(skb)))
+                       goto drop_and_free;
+       }
+
+       /* Adding to request queue in metasocket */
+       mptcp_v6_reqsk_queue_hash_add(meta_sk, req, TCP_TIMEOUT_INIT);
+
+       return;
+
+drop_and_release:
+       dst_release(dst);
+drop_and_free:
+       reqsk_free(req);
+       return;
+}
+
+int mptcp_v6_rem_raddress(struct mptcp_cb *mpcb, u8 id)
+{
+       int i;
+
+       for (i = 0; i < MPTCP_MAX_ADDR; i++) {
+               if (!((1 << i) & mpcb->rem6_bits))
+                       continue;
+
+               if (mpcb->remaddr6[i].rem6_id == id) {
+                       /* remove address from bitfield */
+                       mpcb->rem6_bits &= ~(1 << i);
+
+                       return 0;
+               }
+       }
+
+       return -1;
+}
+
+/* Returns -1 if there is no space anymore to store an additional
+ * address
+ */
+int mptcp_v6_add_raddress(struct mptcp_cb *mpcb, const struct in6_addr *addr,
+                         __be16 port, u8 id)
+{
+       int i;
+       struct mptcp_rem6 *rem6;
+
+       mptcp_for_each_bit_set(mpcb->rem6_bits, i) {
+               rem6 = &mpcb->remaddr6[i];
+
+               /* Address is already in the list --- continue */
+               if (rem6->rem6_id == id &&
+                   ipv6_addr_equal(&rem6->addr, addr) && rem6->port == port)
+                       return 0;
+
+               /* This may be the case, when the peer is behind a NAT. He is
+                * trying to JOIN, thus sending the JOIN with a certain ID.
+                * However the src_addr of the IP-packet has been changed. We
+                * update the addr in the list, because this is the address as
+                * OUR BOX sees it.
+                */
+               if (rem6->rem6_id == id) {
+                       /* update the address */
+                       mptcp_debug("%s: updating old addr: %pI6 to addr %pI6 with id:%d\n",
+                                   __func__, &rem6->addr, addr, id);
+                       rem6->addr = *addr;
+                       rem6->port = port;
+                       mpcb->list_rcvd = 1;
+                       return 0;
+               }
+       }
+
+       i = mptcp_find_free_index(mpcb->rem6_bits);
+       /* Do we have already the maximum number of local/remote addresses? */
+       if (i < 0) {
+               mptcp_debug("%s: At max num of remote addresses: %d --- not adding address: %pI6\n",
+                           __func__, MPTCP_MAX_ADDR, addr);
+               return -1;
+       }
+
+       rem6 = &mpcb->remaddr6[i];
+
+       /* Address is not known yet, store it */
+       rem6->addr = *addr;
+       rem6->port = port;
+       rem6->bitfield = 0;
+       rem6->retry_bitfield = 0;
+       rem6->rem6_id = id;
+       mpcb->list_rcvd = 1;
+       mpcb->rem6_bits |= (1 << i);
+
+       return 0;
+}
+
+/* Sets the bitfield of the remote-address field
+ * local address is not set as it will disappear with the global address-list
+ */
+void mptcp_v6_set_init_addr_bit(struct mptcp_cb *mpcb,
+                               const struct in6_addr *daddr, int index)
+{
+       int i;
+       mptcp_for_each_bit_set(mpcb->rem6_bits, i) {
+               if (ipv6_addr_equal(&mpcb->remaddr6[i].addr, daddr)) {
+                       mpcb->remaddr6[i].bitfield |= (1 << index);
+                       return;
+               }
+       }
+}
+
+int mptcp_v6_do_rcv(struct sock *meta_sk, struct sk_buff *skb)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct sock *child, *rsk = NULL;
+       int ret;
+
+       if (!(TCP_SKB_CB(skb)->mptcp_flags & MPTCPHDR_JOIN)) {
+               struct tcphdr *th = tcp_hdr(skb);
+               const struct ipv6hdr *ip6h = ipv6_hdr(skb);
+               struct sock *sk;
+
+               sk = __inet6_lookup_established(sock_net(meta_sk),
+                                               &tcp_hashinfo,
+                                               &ip6h->saddr, th->source,
+                                               &ip6h->daddr, ntohs(th->dest),
+                                               inet6_iif(skb));
+
+               if (!sk) {
+                       kfree_skb(skb);
+                       return 0;
+               }
+               if (is_meta_sk(sk)) {
+                       WARN("%s Did not find a sub-sk!\n", __func__);
+                       kfree_skb(skb);
+                       sock_put(sk);
+                       return 0;
+               }
+
+               if (sk->sk_state == TCP_TIME_WAIT) {
+                       inet_twsk_put(inet_twsk(sk));
+                       kfree_skb(skb);
+                       return 0;
+               }
+
+               ret = tcp_v6_do_rcv(sk, skb);
+               sock_put(sk);
+
+               return ret;
+       }
+       TCP_SKB_CB(skb)->mptcp_flags = 0;
+
+       /* Has been removed from the tk-table. Thus, no new subflows.
+        *
+        * Check for close-state is necessary, because we may have been closed
+        * without passing by mptcp_close().
+        *
+        * When falling back, no new subflows are allowed either.
+        */
+       if (meta_sk->sk_state == TCP_CLOSE || !tcp_sk(meta_sk)->inside_tk_table ||
+           mpcb->infinite_mapping_rcv || mpcb->send_infinite_mapping)
+               goto reset_and_discard;
+
+       child = tcp_v6_hnd_req(meta_sk, skb);
+
+       if (!child)
+               goto discard;
+
+       if (child != meta_sk) {
+               sock_rps_save_rxhash(child, skb);
+               /* We don't call tcp_child_process here, because we hold
+                * already the meta-sk-lock and are sure that it is not owned
+                * by the user.
+                */
+               ret = tcp_rcv_state_process(child, skb, tcp_hdr(skb), skb->len);
+               bh_unlock_sock(child);
+               sock_put(child);
+               if (ret) {
+                       rsk = child;
+                       goto reset_and_discard;
+               }
+       } else {
+               if (tcp_hdr(skb)->syn) {
+                       struct mp_join *join_opt = mptcp_find_join(skb);
+                       /* Currently we make two calls to mptcp_find_join(). This
+                        * can probably be optimized. */
+                       if (mptcp_v6_add_raddress(mpcb,
+                                                 (struct in6_addr *)&ipv6_hdr(skb)->saddr,
+                                                 0,
+                                                 join_opt->addr_id) < 0)
+                               goto reset_and_discard;
+                       mpcb->list_rcvd = 0;
+
+                       mptcp_v6_join_request(meta_sk, skb);
+                       goto discard;
+               }
+               goto reset_and_discard;
+       }
+       return 0;
+
+reset_and_discard:
+       tcp_v6_send_reset(rsk, skb);
+discard:
+       kfree_skb(skb);
+       return 0;
+}
+
+/* After this, the ref count of the meta_sk associated with the request_sock
+ * is incremented. Thus it is the responsibility of the caller
+ * to call sock_put() when the reference is not needed anymore.
+ */
+struct sock *mptcp_v6_search_req(const __be16 rport, const struct in6_addr *raddr,
+                                const struct in6_addr *laddr, const struct net *net)
+{
+       struct mptcp_request_sock *mtreq;
+       struct sock *meta_sk = NULL;
+
+       spin_lock(&mptcp_reqsk_hlock);
+       list_for_each_entry(mtreq,
+                           &mptcp_reqsk_htb[inet6_synq_hash(raddr, rport, 0,
+                                                            MPTCP_HASH_SIZE)],
+                           collide_tuple) {
+               struct inet_request_sock *treq = inet_rsk(rev_mptcp_rsk(mtreq));
+               meta_sk = mtreq->mpcb->meta_sk;
+
+               if (inet_rsk(rev_mptcp_rsk(mtreq))->ir_rmt_port == rport &&
+                   rev_mptcp_rsk(mtreq)->rsk_ops->family == AF_INET6 &&
+                   ipv6_addr_equal(&treq->ir_v6_rmt_addr, raddr) &&
+                   ipv6_addr_equal(&treq->ir_v6_loc_addr, laddr) &&
+                   net_eq(net, sock_net(meta_sk)))
+                       break;
+               meta_sk = NULL;
+       }
+
+       if (meta_sk && unlikely(!atomic_inc_not_zero(&meta_sk->sk_refcnt)))
+               meta_sk = NULL;
+       spin_unlock(&mptcp_reqsk_hlock);
+
+       return meta_sk;
+}
+
+/* Create a new IPv6 subflow.
+ *
+ * We are in user-context and meta-sock-lock is hold.
+ */
+int mptcp_init6_subsockets(struct sock *meta_sk, const struct mptcp_loc6 *loc,
+                          struct mptcp_rem6 *rem)
+{
+       struct tcp_sock *tp;
+       struct sock *sk;
+       struct sockaddr_in6 loc_in, rem_in;
+       struct socket sock;
+       int ulid_size = 0, ret;
+
+       /** First, create and prepare the new socket */
+
+       sock.type = meta_sk->sk_socket->type;
+       sock.state = SS_UNCONNECTED;
+       sock.wq = meta_sk->sk_socket->wq;
+       sock.file = meta_sk->sk_socket->file;
+       sock.ops = NULL;
+
+       ret = inet6_create(sock_net(meta_sk), &sock, IPPROTO_TCP, 1);
+       if (unlikely(ret < 0)) {
+               mptcp_debug("%s inet6_create failed ret: %d\n", __func__, ret);
+               return ret;
+       }
+
+       sk = sock.sk;
+       tp = tcp_sk(sk);
+
+       /* All subsockets need the MPTCP-lock-class */
+       lockdep_set_class_and_name(&(sk)->sk_lock.slock, &meta_slock_key, "slock-AF_INET-MPTCP");
+       lockdep_init_map(&(sk)->sk_lock.dep_map, "sk_lock-AF_INET-MPTCP", &meta_key, 0);
+
+       if (mptcp_add_sock(meta_sk, sk, loc->loc6_id, rem->rem6_id, GFP_KERNEL))
+               goto error;
+
+       tp->mptcp->slave_sk = 1;
+       tp->mptcp->low_prio = loc->low_prio;
+
+       /* Initializing the timer for an MPTCP subflow */
+       setup_timer(&tp->mptcp->mptcp_ack_timer, mptcp_ack_handler, (unsigned long)sk);
+
+       /** Then, connect the socket to the peer */
+
+       ulid_size = sizeof(struct sockaddr_in6);
+       loc_in.sin6_family = AF_INET6;
+       rem_in.sin6_family = AF_INET6;
+       loc_in.sin6_port = 0;
+       if (rem->port)
+               rem_in.sin6_port = rem->port;
+       else
+               rem_in.sin6_port = inet_sk(meta_sk)->inet_dport;
+       loc_in.sin6_addr = loc->addr;
+       rem_in.sin6_addr = rem->addr;
+
+       ret = sock.ops->bind(&sock, (struct sockaddr *)&loc_in, ulid_size);
+       if (ret < 0) {
+               mptcp_debug("%s: MPTCP subsocket bind()failed, error %d\n",
+                           __func__, ret);
+               goto error;
+       }
+
+       mptcp_debug("%s: token %#x pi %d src_addr:%pI6:%d dst_addr:%pI6:%d\n",
+                   __func__, tcp_sk(meta_sk)->mpcb->mptcp_loc_token,
+                   tp->mptcp->path_index, &loc_in.sin6_addr,
+                   ntohs(loc_in.sin6_port), &rem_in.sin6_addr,
+                   ntohs(rem_in.sin6_port));
+
+       ret = sock.ops->connect(&sock, (struct sockaddr *)&rem_in,
+                               ulid_size, O_NONBLOCK);
+       if (ret < 0 && ret != -EINPROGRESS) {
+               mptcp_debug("%s: MPTCP subsocket connect() failed, error %d\n",
+                           __func__, ret);
+               goto error;
+       }
+
+       sk_set_socket(sk, meta_sk->sk_socket);
+       sk->sk_wq = meta_sk->sk_wq;
+
+       return 0;
+
+error:
+       /* May happen if mptcp_add_sock fails first */
+       if (!tp->mpc) {
+               tcp_close(sk, 0);
+       } else {
+               local_bh_disable();
+               mptcp_sub_force_close(sk);
+               local_bh_enable();
+       }
+       return ret;
+}
+EXPORT_SYMBOL(mptcp_init6_subsockets);
+
+int mptcp_pm_v6_init(void)
+{
+       int ret = 0;
+       struct request_sock_ops *ops = &mptcp6_request_sock_ops;
+
+       ops->slab_name = kasprintf(GFP_KERNEL, "request_sock_%s", "MPTCP6");
+       if (ops->slab_name == NULL) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       ops->slab = kmem_cache_create(ops->slab_name, ops->obj_size, 0,
+                                     SLAB_DESTROY_BY_RCU|SLAB_HWCACHE_ALIGN,
+                                     NULL);
+
+       if (ops->slab == NULL) {
+               ret =  -ENOMEM;
+               goto err_reqsk_create;
+       }
+
+out:
+       return ret;
+
+err_reqsk_create:
+       kfree(ops->slab_name);
+       ops->slab_name = NULL;
+       goto out;
+}
+
+void mptcp_pm_v6_undo(void)
+{
+       kmem_cache_destroy(mptcp6_request_sock_ops.slab);
+       kfree(mptcp6_request_sock_ops.slab_name);
+}
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_ndiffports.c linux-3.14.45/net/mptcp/mptcp_ndiffports.c
--- linux-3.14.45.orig/net/mptcp/mptcp_ndiffports.c     1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_ndiffports.c  2015-06-24 14:15:48.931862523 +0200
@@ -0,0 +1,171 @@
+#include <linux/module.h>
+
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/mptcp_v6.h>
+#endif
+
+struct ndiffports_priv {
+       /* Worker struct for subflow establishment */
+       struct work_struct subflow_work;
+
+       struct mptcp_cb *mpcb;
+};
+
+static int sysctl_mptcp_ndiffports __read_mostly = 2;
+
+/**
+ * Create all new subflows, by doing calls to mptcp_initX_subsockets
+ *
+ * This function uses a goto next_subflow, to allow releasing the lock between
+ * new subflows and giving other processes a chance to do some work on the
+ * socket and potentially finishing the communication.
+ **/
+static void create_subflow_worker(struct work_struct *work)
+{
+       struct ndiffports_priv *pm_priv = container_of(work,
+                                                    struct ndiffports_priv,
+                                                    subflow_work);
+       struct mptcp_cb *mpcb = pm_priv->mpcb;
+       struct sock *meta_sk = mpcb->meta_sk;
+       int iter = 0;
+
+next_subflow:
+       if (iter) {
+               release_sock(meta_sk);
+               mutex_unlock(&mpcb->mpcb_mutex);
+
+               yield();
+       }
+       mutex_lock(&mpcb->mpcb_mutex);
+       lock_sock_nested(meta_sk, SINGLE_DEPTH_NESTING);
+
+       iter++;
+
+       if (sock_flag(meta_sk, SOCK_DEAD))
+               goto exit;
+
+       if (mpcb->master_sk &&
+           !tcp_sk(mpcb->master_sk)->mptcp->fully_established)
+               goto exit;
+
+       if (sysctl_mptcp_ndiffports > iter &&
+           sysctl_mptcp_ndiffports > mpcb->cnt_subflows) {
+               if (meta_sk->sk_family == AF_INET ||
+                   mptcp_v6_is_v4_mapped(meta_sk)) {
+                       struct mptcp_loc4 loc;
+
+                       loc.addr.s_addr = inet_sk(meta_sk)->inet_saddr;
+                       loc.loc4_id = 0;
+                       loc.low_prio = 0;
+
+                       mptcp_init4_subsockets(meta_sk, &loc, &mpcb->remaddr4[0]);
+               } else {
+#if IS_ENABLED(CONFIG_IPV6)
+                       struct mptcp_loc6 loc;
+
+                       loc.addr = inet6_sk(meta_sk)->saddr;
+                       loc.loc6_id = 0;
+                       loc.low_prio = 0;
+
+                       mptcp_init6_subsockets(meta_sk, &loc, &mpcb->remaddr6[0]);
+#endif
+               }
+               goto next_subflow;
+       }
+
+exit:
+       release_sock(meta_sk);
+       mutex_unlock(&mpcb->mpcb_mutex);
+       sock_put(meta_sk);
+}
+
+static void ndiffports_new_session(struct sock *meta_sk, int index)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct ndiffports_priv *fmp = (struct ndiffports_priv *)&mpcb->mptcp_pm[0];
+
+       /* Initialize workqueue-struct */
+       INIT_WORK(&fmp->subflow_work, create_subflow_worker);
+       fmp->mpcb = mpcb;
+}
+
+static void ndiffports_create_subflows(struct sock *meta_sk)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct ndiffports_priv *pm_priv = (struct ndiffports_priv *)&mpcb->mptcp_pm[0];
+
+       if (mpcb->infinite_mapping_snd || mpcb->infinite_mapping_rcv ||
+           mpcb->send_infinite_mapping ||
+           mpcb->server_side || sock_flag(meta_sk, SOCK_DEAD))
+               return;
+
+       if (!work_pending(&pm_priv->subflow_work)) {
+               sock_hold(meta_sk);
+               queue_work(mptcp_wq, &pm_priv->subflow_work);
+       }
+}
+
+static int ndiffports_get_local_index(sa_family_t family, union inet_addr *addr,
+                                     struct net *net)
+{
+       return 0;
+}
+
+static struct mptcp_pm_ops ndiffports __read_mostly = {
+       .new_session = ndiffports_new_session,
+       .fully_established = ndiffports_create_subflows,
+       .get_local_index = ndiffports_get_local_index,
+       .get_local_id = ndiffports_get_local_index,
+       .name = "ndiffports",
+       .owner = THIS_MODULE,
+};
+
+static struct ctl_table ndiff_table[] = {
+       {
+               .procname = "mptcp_ndiffports",
+               .data = &sysctl_mptcp_ndiffports,
+               .maxlen = sizeof(int),
+               .mode = 0644,
+               .proc_handler = &proc_dointvec
+       },
+       { }
+};
+
+struct ctl_table_header *mptcp_sysctl;
+
+/* General initialization of MPTCP_PM */
+static int __init ndiffports_register(void)
+{
+       BUILD_BUG_ON(sizeof(struct ndiffports_priv) > MPTCP_PM_SIZE);
+
+       mptcp_sysctl = register_net_sysctl(&init_net, "net/mptcp", ndiff_table);
+       if (!mptcp_sysctl)
+               goto exit;
+
+       if (mptcp_register_path_manager(&ndiffports))
+               goto pm_failed;
+
+       return 0;
+
+pm_failed:
+       unregister_net_sysctl_table(mptcp_sysctl);
+exit:
+       return -1;
+}
+
+static void ndiffports_unregister(void)
+{
+       mptcp_unregister_path_manager(&ndiffports);
+       unregister_net_sysctl_table(mptcp_sysctl);
+}
+
+module_init(ndiffports_register);
+module_exit(ndiffports_unregister);
+
+MODULE_AUTHOR("Christoph Paasch");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("NDIFF-PORTS MPTCP");
+MODULE_VERSION("0.88");
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_ofo_queue.c linux-3.14.45/net/mptcp/mptcp_ofo_queue.c
--- linux-3.14.45.orig/net/mptcp/mptcp_ofo_queue.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_ofo_queue.c   2015-06-24 14:15:48.931862523 +0200
@@ -0,0 +1,278 @@
+/*
+ *     MPTCP implementation - Fast algorithm for MPTCP meta-reordering
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+
+void mptcp_remove_shortcuts(const struct mptcp_cb *mpcb,
+                           const struct sk_buff *skb)
+{
+       struct tcp_sock *tp;
+
+       mptcp_for_each_tp(mpcb, tp) {
+               if (tp->mptcp->shortcut_ofoqueue == skb) {
+                       tp->mptcp->shortcut_ofoqueue = NULL;
+                       return;
+               }
+       }
+}
+
+/* Does 'skb' fits after 'here' in the queue 'head' ?
+ * If yes, we queue it and return 1
+ */
+static int mptcp_ofo_queue_after(struct sk_buff_head *head,
+                                struct sk_buff *skb, struct sk_buff *here,
+                                struct tcp_sock *tp)
+{
+       struct sock *meta_sk = tp->meta_sk;
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       u32 seq = TCP_SKB_CB(skb)->seq;
+       u32 end_seq = TCP_SKB_CB(skb)->end_seq;
+
+       /* We want to queue skb after here, thus seq >= end_seq */
+       if (before(seq, TCP_SKB_CB(here)->end_seq))
+               return 0;
+
+       if (seq == TCP_SKB_CB(here)->end_seq) {
+               bool fragstolen = false;
+
+               if (!tcp_try_coalesce(meta_sk, here, skb, &fragstolen)) {
+                       __skb_queue_after(&meta_tp->out_of_order_queue, here, skb);
+                       return 1;
+               } else {
+                       kfree_skb_partial(skb, fragstolen);
+                       return -1;
+               }
+       }
+
+       /* If here is the last one, we can always queue it */
+       if (skb_queue_is_last(head, here)) {
+               __skb_queue_after(head, here, skb);
+               return 1;
+       } else {
+               struct sk_buff *skb1 = skb_queue_next(head, here);
+               /* It's not the last one, but does it fits between 'here' and
+                * the one after 'here' ? Thus, does end_seq <= after_here->seq
+                */
+               if (!after(end_seq, TCP_SKB_CB(skb1)->seq)) {
+                       __skb_queue_after(head, here, skb);
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+static void try_shortcut(struct sk_buff *shortcut, struct sk_buff *skb,
+                        struct sk_buff_head *head, struct tcp_sock *tp)
+{
+       struct sock *meta_sk = tp->meta_sk;
+       struct tcp_sock *tp_it, *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       struct sk_buff *skb1, *best_shortcut = NULL;
+       u32 seq = TCP_SKB_CB(skb)->seq;
+       u32 end_seq = TCP_SKB_CB(skb)->end_seq;
+       u32 distance = 0xffffffff;
+
+       /* First, check the tp's shortcut */
+       if (!shortcut) {
+               if (skb_queue_empty(head)) {
+                       __skb_queue_head(head, skb);
+                       goto end;
+               }
+       } else {
+               int ret = mptcp_ofo_queue_after(head, skb, shortcut, tp);
+               /* Does the tp's shortcut is a hit? If yes, we insert. */
+
+               if (ret) {
+                       skb = (ret > 0) ? skb : NULL;
+                       goto end;
+               }
+       }
+
+       /* Check the shortcuts of the other subsockets. */
+       mptcp_for_each_tp(mpcb, tp_it) {
+               shortcut = tp_it->mptcp->shortcut_ofoqueue;
+               /* Can we queue it here? If yes, do so! */
+               if (shortcut) {
+                       int ret = mptcp_ofo_queue_after(head, skb, shortcut, tp);
+
+                       if (ret) {
+                               skb = (ret > 0) ? skb : NULL;
+                               goto end;
+                       }
+               }
+
+               /* Could not queue it, check if we are close.
+                * We are looking for a shortcut, close enough to seq to
+                * set skb1 prematurely and thus improve the subsequent lookup,
+                * which tries to find a skb1 so that skb1->seq <= seq.
+                *
+                * So, here we only take shortcuts, whose shortcut->seq > seq,
+                * and minimize the distance between shortcut->seq and seq and
+                * set best_shortcut to this one with the minimal distance.
+                *
+                * That way, the subsequent while-loop is shortest.
+                */
+               if (shortcut && after(TCP_SKB_CB(shortcut)->seq, seq)) {
+                       /* Are we closer than the current best shortcut? */
+                       if ((u32)(TCP_SKB_CB(shortcut)->seq - seq) < distance) {
+                               distance = (u32)(TCP_SKB_CB(shortcut)->seq - seq);
+                               best_shortcut = shortcut;
+                       }
+               }
+       }
+
+       if (best_shortcut)
+               skb1 = best_shortcut;
+       else
+               skb1 = skb_peek_tail(head);
+
+       if (seq == TCP_SKB_CB(skb1)->end_seq) {
+               bool fragstolen = false;
+
+               if (!tcp_try_coalesce(meta_sk, skb1, skb, &fragstolen)) {
+                       __skb_queue_after(&meta_tp->out_of_order_queue, skb1, skb);
+               } else {
+                       kfree_skb_partial(skb, fragstolen);
+                       skb = NULL;
+               }
+
+               goto end;
+       }
+
+       /* Find the insertion point, starting from best_shortcut if available.
+        *
+        * Inspired from tcp_data_queue_ofo.
+        */
+       while (1) {
+               /* skb1->seq <= seq */
+               if (!after(TCP_SKB_CB(skb1)->seq, seq))
+                       break;
+               if (skb_queue_is_first(head, skb1)) {
+                       skb1 = NULL;
+                       break;
+               }
+               skb1 = skb_queue_prev(head, skb1);
+       }
+
+       /* Do skb overlap to previous one? */
+       if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) {
+               if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
+                       /* All the bits are present. */
+                       __kfree_skb(skb);
+                       skb = NULL;
+                       goto end;
+               }
+               if (seq == TCP_SKB_CB(skb1)->seq) {
+                       if (skb_queue_is_first(head, skb1))
+                               skb1 = NULL;
+                       else
+                               skb1 = skb_queue_prev(head, skb1);
+               }
+       }
+       if (!skb1)
+               __skb_queue_head(head, skb);
+       else
+               __skb_queue_after(head, skb1, skb);
+
+       /* And clean segments covered by new one as whole. */
+       while (!skb_queue_is_last(head, skb)) {
+               skb1 = skb_queue_next(head, skb);
+
+               if (!after(end_seq, TCP_SKB_CB(skb1)->seq))
+                       break;
+
+               __skb_unlink(skb1, head);
+               mptcp_remove_shortcuts(mpcb, skb1);
+               __kfree_skb(skb1);
+       }
+
+end:
+       if (skb) {
+               skb_set_owner_r(skb, meta_sk);
+               tp->mptcp->shortcut_ofoqueue = skb;
+       }
+
+       return;
+}
+
+/**
+ * @sk: the subflow that received this skb.
+ */
+void mptcp_add_meta_ofo_queue(struct sock *meta_sk, struct sk_buff *skb,
+                             struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       try_shortcut(tp->mptcp->shortcut_ofoqueue, skb,
+                    &tcp_sk(meta_sk)->out_of_order_queue, tp);
+}
+
+void mptcp_ofo_queue(struct sock *meta_sk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sk_buff *skb;
+
+       while ((skb = skb_peek(&meta_tp->out_of_order_queue)) != NULL) {
+               u32 old_rcv_nxt = meta_tp->rcv_nxt;
+               if (after(TCP_SKB_CB(skb)->seq, meta_tp->rcv_nxt))
+                       break;
+
+               if (!after(TCP_SKB_CB(skb)->end_seq, meta_tp->rcv_nxt)) {
+                       __skb_unlink(skb, &meta_tp->out_of_order_queue);
+                       mptcp_remove_shortcuts(meta_tp->mpcb, skb);
+                       __kfree_skb(skb);
+                       continue;
+               }
+
+               __skb_unlink(skb, &meta_tp->out_of_order_queue);
+               mptcp_remove_shortcuts(meta_tp->mpcb, skb);
+
+               __skb_queue_tail(&meta_sk->sk_receive_queue, skb);
+               meta_tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+               mptcp_check_rcvseq_wrap(meta_tp, old_rcv_nxt);
+
+               if (tcp_hdr(skb)->fin)
+                       mptcp_fin(meta_sk);
+       }
+}
+
+void mptcp_purge_ofo_queue(struct tcp_sock *meta_tp)
+{
+       struct sk_buff_head *head = &meta_tp->out_of_order_queue;
+       struct sk_buff *skb, *tmp;
+
+       skb_queue_walk_safe(head, skb, tmp) {
+               __skb_unlink(skb, head);
+               mptcp_remove_shortcuts(meta_tp->mpcb, skb);
+               kfree_skb(skb);
+       }
+}
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_olia.c linux-3.14.45/net/mptcp/mptcp_olia.c
--- linux-3.14.45.orig/net/mptcp/mptcp_olia.c   1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_olia.c        2015-06-24 14:15:48.931862523 +0200
@@ -0,0 +1,314 @@
+/*
+ * MPTCP implementation - OPPORTUNISTIC LINKED INCREASES CONGESTION CONTROL:
+ *
+ * Algorithm design:
+ * Ramin Khalili <ramin.khalili@epfl.ch>
+ * Nicolas Gast <nicolas.gast@epfl.ch>
+ * Jean-Yves Le Boudec <jean-yves.leboudec@epfl.ch>
+ *
+ * Implementation:
+ * Ramin Khalili <ramin.khalili@epfl.ch>
+ *
+ * Ported to the official MPTCP-kernel:
+ * Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+
+#include <net/tcp.h>
+#include <net/mptcp.h>
+
+#include <linux/module.h>
+
+static int scale = 10;
+
+struct mptcp_olia {
+       u32     mptcp_loss1;
+       u32     mptcp_loss2;
+       u32     mptcp_loss3;
+       int     epsilon_num;
+       u32     epsilon_den;
+       int     mptcp_snd_cwnd_cnt;
+};
+
+static inline int mptcp_olia_sk_can_send(const struct sock *sk)
+{
+       return mptcp_sk_can_send(sk) && tcp_sk(sk)->srtt;
+}
+
+static inline u64 mptcp_olia_scale(u64 val, int scale)
+{
+       return (u64) val << scale;
+}
+
+/* take care of artificially inflate (see RFC5681)
+ * of cwnd during fast-retransmit phase
+ */
+static u32 mptcp_get_crt_cwnd(struct sock *sk)
+{
+       struct inet_connection_sock *icsk = inet_csk(sk);
+
+       if (icsk->icsk_ca_state == TCP_CA_Recovery)
+               return tcp_sk(sk)->snd_ssthresh;
+       else
+               return tcp_sk(sk)->snd_cwnd;
+}
+
+/* return the dominator of the first term of  the increasing term */
+static u64 mptcp_get_rate(struct mptcp_cb *mpcb , u32 path_rtt)
+{
+       struct sock *sk;
+       u64 rate = 1; /* We have to avoid a zero-rate because it is used as a divisor */
+
+       mptcp_for_each_sk(mpcb, sk) {
+               struct tcp_sock *tp = tcp_sk(sk);
+               u64 scaled_num;
+               u32 tmp_cwnd;
+
+               if (!mptcp_olia_sk_can_send(sk))
+                       continue;
+
+               tmp_cwnd = mptcp_get_crt_cwnd(sk);
+               scaled_num = mptcp_olia_scale(tmp_cwnd, scale) * path_rtt;
+               rate += div_u64(scaled_num , tp->srtt);
+       }
+       rate *= rate;
+       return rate;
+}
+
+/* find the maximum cwnd, used to find set M */
+static u32 mptcp_get_max_cwnd(struct mptcp_cb *mpcb)
+{
+       struct sock *sk;
+       u32 best_cwnd = 0;
+
+       mptcp_for_each_sk(mpcb, sk) {
+               u32 tmp_cwnd;
+
+               if (!mptcp_olia_sk_can_send(sk))
+                       continue;
+
+               tmp_cwnd = mptcp_get_crt_cwnd(sk);
+               if (tmp_cwnd > best_cwnd)
+                       best_cwnd = tmp_cwnd;
+       }
+       return best_cwnd;
+}
+
+static void mptcp_get_epsilon(struct mptcp_cb *mpcb)
+{
+       struct mptcp_olia *ca;
+       struct tcp_sock *tp;
+       struct sock *sk;
+       u64 tmp_int, tmp_rtt, best_int = 0, best_rtt = 1;
+       u32 max_cwnd = 1, best_cwnd = 1, tmp_cwnd;
+       u8 M = 0, B_not_M = 0;
+
+       /* TODO - integrate this in the following loop - we just want to iterate once */
+
+       max_cwnd = mptcp_get_max_cwnd(mpcb);
+
+       /* find the best path */
+       mptcp_for_each_sk(mpcb, sk) {
+               tp = tcp_sk(sk);
+               ca = inet_csk_ca(sk);
+
+               if (!mptcp_olia_sk_can_send(sk))
+                       continue;
+
+               tmp_rtt = tp->srtt * tp->srtt;
+               /* TODO - check here and rename variables */
+               tmp_int = max(ca->mptcp_loss3 - ca->mptcp_loss2,
+                             ca->mptcp_loss2 - ca->mptcp_loss1);
+
+               tmp_cwnd = mptcp_get_crt_cwnd(sk);
+               if (tmp_int * best_rtt >= best_int * tmp_rtt) {
+                       best_rtt = tmp_rtt;
+                       best_int = tmp_int;
+                       best_cwnd = tmp_cwnd;
+               }
+       }
+
+       /* TODO - integrate this here in mptcp_get_max_cwnd and in the previous loop */
+       /* find the size of M and B_not_M */
+       mptcp_for_each_sk(mpcb, sk) {
+               tp = tcp_sk(sk);
+               ca = inet_csk_ca(sk);
+
+               if (!mptcp_olia_sk_can_send(sk))
+                       continue;
+
+               tmp_cwnd = mptcp_get_crt_cwnd(sk);
+               if (tmp_cwnd == max_cwnd) {
+                       M++;
+               } else {
+                       tmp_rtt = tp->srtt * tp->srtt;
+                       tmp_int = max(ca->mptcp_loss3 - ca->mptcp_loss2,
+                                     ca->mptcp_loss2 - ca->mptcp_loss1);
+
+                       if (tmp_int * best_rtt == best_int * tmp_rtt)
+                               B_not_M++;
+               }
+       }
+
+       /* check if the path is in M or B_not_M and set the value of epsilon accordingly */
+       mptcp_for_each_sk(mpcb, sk) {
+               tp = tcp_sk(sk);
+               ca = inet_csk_ca(sk);
+
+               if (!mptcp_olia_sk_can_send(sk))
+                       continue;
+
+               if (B_not_M == 0) {
+                       ca->epsilon_num = 0;
+                       ca->epsilon_den = 1;
+               } else {
+                       tmp_rtt = tp->srtt * tp->srtt;
+                       tmp_int = max(ca->mptcp_loss3 - ca->mptcp_loss2,
+                                     ca->mptcp_loss2 - ca->mptcp_loss1);
+                       tmp_cwnd = mptcp_get_crt_cwnd(sk);
+
+                       if (tmp_cwnd < max_cwnd &&
+                           tmp_int * best_rtt == best_int * tmp_rtt){
+                               ca->epsilon_num = 1;
+                               ca->epsilon_den = mpcb->cnt_established * B_not_M;
+                       } else if (tmp_cwnd == max_cwnd) {
+                               ca->epsilon_num = -1;
+                               ca->epsilon_den = mpcb->cnt_established  * M;
+                       } else {
+                               ca->epsilon_num = 0;
+                               ca->epsilon_den = 1;
+                       }
+               }
+       }
+
+}
+
+/* setting the initial values */
+static void mptcp_olia_init(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct mptcp_olia *ca = inet_csk_ca(sk);
+
+       if (tp->mpc) {
+               ca->mptcp_loss1 = tp->snd_una;
+               ca->mptcp_loss2 = tp->snd_una;
+               ca->mptcp_loss3 = tp->snd_una;
+               ca->mptcp_snd_cwnd_cnt = 0;
+               ca->epsilon_num = 0;
+               ca->epsilon_den = 1;
+       }
+}
+
+/* updating inter-loss distance and ssthresh */
+static void mptcp_olia_set_state(struct sock *sk, u8 new_state)
+{
+       if (!tcp_sk(sk)->mpc)
+               return;
+
+       if (new_state == TCP_CA_Loss ||
+           new_state == TCP_CA_Recovery || new_state == TCP_CA_CWR) {
+               struct mptcp_olia *ca = inet_csk_ca(sk);
+
+               if (ca->mptcp_loss3 != ca->mptcp_loss2 &&
+                   !inet_csk(sk)->icsk_retransmits) {
+                       ca->mptcp_loss1 = ca->mptcp_loss2;
+                       ca->mptcp_loss2 = ca->mptcp_loss3;
+               }
+       }
+
+}
+
+/* main algorithm */
+static void mptcp_olia_cong_avoid(struct sock *sk, u32 ack, u32 acked, u32 in_flight)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct mptcp_olia *ca = inet_csk_ca(sk);
+       struct mptcp_cb *mpcb = tp->mpcb;
+
+       u64 inc_num, inc_den, rate, cwnd_scaled;
+
+       if (!tp->mpc) {
+               tcp_reno_cong_avoid(sk, ack, acked, in_flight);
+               return;
+       }
+
+       ca->mptcp_loss3 = tp->snd_una;
+
+       if (!tcp_is_cwnd_limited(sk, in_flight))
+               return;
+
+       /* slow start if it is in the safe area */
+       if (tp->snd_cwnd <= tp->snd_ssthresh) {
+               tcp_slow_start(tp, acked);
+               return;
+       }
+
+       mptcp_get_epsilon(mpcb);
+       rate = mptcp_get_rate(mpcb, tp->srtt);
+       cwnd_scaled = mptcp_olia_scale(tp->snd_cwnd, scale);
+       inc_den = ca->epsilon_den * tp->snd_cwnd * rate ? : 1;
+
+       /* calculate the increasing term, scaling is used to reduce the rounding effect */
+       if (ca->epsilon_num == -1) {
+               if (ca->epsilon_den * cwnd_scaled * cwnd_scaled < rate) {
+                       inc_num = rate - ca->epsilon_den *
+                               cwnd_scaled * cwnd_scaled;
+                       ca->mptcp_snd_cwnd_cnt -= div64_u64(
+                           mptcp_olia_scale(inc_num , scale) , inc_den);
+               } else {
+                       inc_num = ca->epsilon_den *
+                           cwnd_scaled * cwnd_scaled - rate;
+                       ca->mptcp_snd_cwnd_cnt += div64_u64(
+                           mptcp_olia_scale(inc_num , scale) , inc_den);
+               }
+       } else {
+               inc_num = ca->epsilon_num * rate +
+                   ca->epsilon_den * cwnd_scaled * cwnd_scaled;
+               ca->mptcp_snd_cwnd_cnt += div64_u64(
+                   mptcp_olia_scale(inc_num , scale) , inc_den);
+       }
+
+
+       if (ca->mptcp_snd_cwnd_cnt >= (1 << scale) - 1) {
+               if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+                       tp->snd_cwnd++;
+               ca->mptcp_snd_cwnd_cnt = 0;
+       } else if (ca->mptcp_snd_cwnd_cnt <= 0 - (1 << scale) + 1) {
+               tp->snd_cwnd = max((int) 1 , (int) tp->snd_cwnd - 1);
+               ca->mptcp_snd_cwnd_cnt = 0;
+       }
+}
+
+static struct tcp_congestion_ops mptcp_olia = {
+       .init           = mptcp_olia_init,
+       .ssthresh       = tcp_reno_ssthresh,
+       .cong_avoid     = mptcp_olia_cong_avoid,
+       .set_state      = mptcp_olia_set_state,
+       .min_cwnd       = tcp_reno_min_cwnd,
+       .owner          = THIS_MODULE,
+       .name           = "olia",
+};
+
+static int __init mptcp_olia_register(void)
+{
+       BUILD_BUG_ON(sizeof(struct mptcp_olia) > ICSK_CA_PRIV_SIZE);
+       return tcp_register_congestion_control(&mptcp_olia);
+}
+
+static void __exit mptcp_olia_unregister(void)
+{
+       tcp_unregister_congestion_control(&mptcp_olia);
+}
+
+module_init(mptcp_olia_register);
+module_exit(mptcp_olia_unregister);
+
+MODULE_AUTHOR("Ramin Khalili, Nicolas Gast, Jean-Yves Le Boudec");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MPTCP COUPLED CONGESTION CONTROL");
+MODULE_VERSION("0.1");
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_output.c linux-3.14.45/net/mptcp/mptcp_output.c
--- linux-3.14.45.orig/net/mptcp/mptcp_output.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_output.c      2015-06-24 14:15:48.931862523 +0200
@@ -0,0 +1,2255 @@
+/*
+ *     MPTCP implementation - Sending side
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kconfig.h>
+#include <linux/skbuff.h>
+#include <linux/tcp.h>
+
+#include <net/mptcp.h>
+#include <net/mptcp_v4.h>
+#include <net/mptcp_v6.h>
+#include <net/sock.h>
+
+static inline int mptcp_pi_to_flag(int pi)
+{
+       return 1 << (pi - 1);
+}
+
+static inline int mptcp_sub_len_remove_addr(u16 bitfield)
+{
+       unsigned int c;
+       for (c = 0; bitfield; c++)
+               bitfield &= bitfield - 1;
+       return MPTCP_SUB_LEN_REMOVE_ADDR + c - 1;
+}
+
+int mptcp_sub_len_remove_addr_align(u16 bitfield)
+{
+       return ALIGN(mptcp_sub_len_remove_addr(bitfield), 4);
+}
+EXPORT_SYMBOL(mptcp_sub_len_remove_addr_align);
+
+/* If the sub-socket sk available to send the skb? */
+static int mptcp_is_available(struct sock *sk, struct sk_buff *skb,
+                             unsigned int *mss)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       unsigned int mss_now;
+
+       /* Set of states for which we are allowed to send data */
+       if (!mptcp_sk_can_send(sk))
+               return 0;
+
+       /* We do not send data on this subflow unless it is
+        * fully established, i.e. the 4th ack has been received.
+        */
+       if (tp->mptcp->pre_established)
+               return 0;
+
+       if (tp->pf ||
+           (tp->mpcb->noneligible & mptcp_pi_to_flag(tp->mptcp->path_index)))
+               return 0;
+
+       if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss) {
+               /* If SACK is disabled, and we got a loss, TCP does not exit
+                * the loss-state until something above high_seq has been acked.
+                * (see tcp_try_undo_recovery)
+                *
+                * high_seq is the snd_nxt at the moment of the RTO. As soon
+                * as we have an RTO, we won't push data on the subflow.
+                * Thus, snd_una can never go beyond high_seq.
+                */
+               if (!tcp_is_reno(tp))
+                       return 0;
+               else if (tp->snd_una != tp->high_seq)
+                       return 0;
+       }
+
+       if (!tp->mptcp->fully_established) {
+               /* Make sure that we send in-order data */
+               if (skb && tp->mptcp->second_packet &&
+                   tp->mptcp->last_end_data_seq != TCP_SKB_CB(skb)->seq)
+                       return 0;
+       }
+
+       if (!tcp_cwnd_test(tp, skb))
+               return 0;
+
+       mss_now = tcp_current_mss(sk);
+       /* Don't send on this subflow if we bypass the allowed send-window at
+        * the per-subflow level. Similar to tcp_snd_wnd_test, but manually
+        * calculated end_seq (because here at this point end_seq is still at
+        * the meta-level).
+        */
+       if (skb && after(tp->write_seq + min(skb->len, mss_now), tcp_wnd_end(tp)))
+               return 0;
+
+       if (mss)
+               *mss = mss_now;
+
+       return 1;
+}
+
+/* Are we not allowed to reinject this skb on tp? */
+static int mptcp_dont_reinject_skb(struct tcp_sock *tp, struct sk_buff *skb)
+{
+       /* If the skb has already been enqueued in this sk, try to find
+        * another one.
+        */
+       return skb &&
+               /* Has the skb already been enqueued into this subsocket? */
+               mptcp_pi_to_flag(tp->mptcp->path_index) & TCP_SKB_CB(skb)->path_mask;
+}
+
+/* This is the scheduler. This function decides on which flow to send
+ * a given MSS. If all subflows are found to be busy, NULL is returned
+ * The flow is selected based on the shortest RTT.
+ * If all paths have full cong windows, we simply return NULL.
+ *
+ * Additionally, this function is aware of the backup-subflows.
+ */
+static struct sock *get_available_subflow(struct sock *meta_sk,
+                                         struct sk_buff *skb,
+                                         unsigned int *mss_now)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct sock *sk, *bestsk = NULL, *lowpriosk = NULL, *backupsk = NULL;
+       unsigned int mss = 0, mss_lowprio = 0, mss_backup = 0;
+       u32 min_time_to_peer = 0xffffffff, lowprio_min_time_to_peer = 0xffffffff;
+       int cnt_backups = 0;
+
+       /* if there is only one subflow, bypass the scheduling function */
+       if (mpcb->cnt_subflows == 1) {
+               bestsk = (struct sock *)mpcb->connection_list;
+               if (!mptcp_is_available(bestsk, skb, mss_now))
+                       bestsk = NULL;
+               return bestsk;
+       }
+
+       /* Answer data_fin on same subflow!!! */
+       if (meta_sk->sk_shutdown & RCV_SHUTDOWN &&
+           skb && mptcp_is_data_fin(skb)) {
+               mptcp_for_each_sk(mpcb, sk) {
+                       if (tcp_sk(sk)->mptcp->path_index == mpcb->dfin_path_index &&
+                           mptcp_is_available(sk, skb, mss_now))
+                               return sk;
+               }
+       }
+
+       /* First, find the best subflow */
+       mptcp_for_each_sk(mpcb, sk) {
+               struct tcp_sock *tp = tcp_sk(sk);
+               int this_mss;
+
+               if (tp->mptcp->rcv_low_prio || tp->mptcp->low_prio)
+                       cnt_backups++;
+
+               if ((tp->mptcp->rcv_low_prio || tp->mptcp->low_prio) &&
+                   tp->srtt < lowprio_min_time_to_peer) {
+
+                       if (!mptcp_is_available(sk, skb, &this_mss))
+                               continue;
+
+                       if (mptcp_dont_reinject_skb(tp, skb)) {
+                               mss_backup = this_mss;
+                               backupsk = sk;
+                               continue;
+                       }
+
+                       lowprio_min_time_to_peer = tp->srtt;
+                       lowpriosk = sk;
+                       mss_lowprio = this_mss;
+               } else if (!(tp->mptcp->rcv_low_prio || tp->mptcp->low_prio) &&
+                          tp->srtt < min_time_to_peer) {
+                       if (!mptcp_is_available(sk, skb, &this_mss))
+                               continue;
+
+                       if (mptcp_dont_reinject_skb(tp, skb)) {
+                               mss_backup = this_mss;
+                               backupsk = sk;
+                               continue;
+                       }
+
+                       min_time_to_peer = tp->srtt;
+                       bestsk = sk;
+                       mss = this_mss;
+               }
+       }
+
+       if (mpcb->cnt_established == cnt_backups && lowpriosk) {
+               mss = mss_lowprio;
+               sk = lowpriosk;
+       } else if (bestsk) {
+               sk = bestsk;
+       } else if (backupsk){
+               /* It has been sent on all subflows once - let's give it a
+                * chance again by restarting its pathmask.
+                */
+               if (skb)
+                       TCP_SKB_CB(skb)->path_mask = 0;
+               mss = mss_backup;
+               sk = backupsk;
+       }
+
+       if (mss_now)
+               *mss_now = mss;
+
+       return sk;
+}
+
+static struct mp_dss *mptcp_skb_find_dss(const struct sk_buff *skb)
+{
+       if (!mptcp_is_data_seq(skb))
+               return NULL;
+
+       return (struct mp_dss *)(skb->data - (MPTCP_SUB_LEN_DSS_ALIGN +
+                                             MPTCP_SUB_LEN_ACK_ALIGN +
+                                             MPTCP_SUB_LEN_SEQ_ALIGN));
+}
+
+/* get the data-seq and end-data-seq and store them again in the
+ * tcp_skb_cb
+ */
+static int mptcp_reconstruct_mapping(struct sk_buff *skb, struct sk_buff *orig_skb)
+{
+       struct mp_dss *mpdss = mptcp_skb_find_dss(orig_skb);
+       u32 *p32;
+       u16 *p16;
+
+       if (!mpdss || !mpdss->M)
+               return 1;
+
+       /* Move the pointer to the data-seq */
+       p32 = (u32 *)mpdss;
+       p32++;
+       if (mpdss->A) {
+               p32++;
+               if (mpdss->a)
+                       p32++;
+       }
+
+       TCP_SKB_CB(skb)->seq = ntohl(*p32);
+
+       /* Get the data_len to calculate the end_data_seq */
+       p32++;
+       p32++;
+       p16 = (u16 *)p32;
+       TCP_SKB_CB(skb)->end_seq = ntohs(*p16) + TCP_SKB_CB(skb)->seq;
+
+       return 0;
+}
+
+/* Similar to __pskb_copy and sk_stream_alloc_skb. */
+static struct sk_buff *mptcp_pskb_copy(struct sk_buff *skb)
+{
+       struct sk_buff *n;
+       /* The TCP header must be at least 32-bit aligned.  */
+       int size = ALIGN(skb_headlen(skb), 4);
+
+       n = alloc_skb_fclone(size + MAX_TCP_HEADER, GFP_ATOMIC);
+       if (!n)
+               return NULL;
+
+       /* Set the data pointer */
+       skb_reserve(n, MAX_TCP_HEADER);
+       /* Set the tail pointer and length */
+       skb_put(n, skb_headlen(skb));
+       /* Copy the bytes */
+       skb_copy_from_linear_data(skb, n->data, n->len);
+
+       n->truesize += skb->data_len;
+       n->data_len  = skb->data_len;
+       n->len       = skb->len;
+
+       if (skb_shinfo(skb)->nr_frags) {
+               int i;
+
+               if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
+                       if (skb_copy_ubufs(skb, GFP_ATOMIC)) {
+                               kfree_skb(n);
+                               n = NULL;
+                               goto out;
+                       }
+               }
+               for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+                       skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
+                       skb_frag_ref(skb, i);
+               }
+               skb_shinfo(n)->nr_frags = i;
+       }
+
+       if (skb_has_frag_list(skb)) {
+               skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
+               skb_clone_fraglist(n);
+       }
+
+       copy_skb_header(n, skb);
+out:
+       return n;
+}
+
+/* Reinject data from one TCP subflow to the meta_sk. If sk == NULL, we are
+ * coming from the meta-retransmit-timer
+ */
+static void __mptcp_reinject_data(struct sk_buff *orig_skb, struct sock *meta_sk,
+                                 struct sock *sk, int clone_it)
+{
+       struct sk_buff *skb, *skb1;
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       u32 seq, end_seq;
+
+       if (clone_it) {
+               /* pskb_copy is necessary here, because the TCP/IP-headers
+                * will be changed when it's going to be reinjected on another
+                * subflow.
+                */
+               skb = mptcp_pskb_copy(orig_skb);
+       } else {
+               __skb_unlink(orig_skb, &sk->sk_write_queue);
+               sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
+               sk->sk_wmem_queued -= orig_skb->truesize;
+               sk_mem_uncharge(sk, orig_skb->truesize);
+               skb = orig_skb;
+       }
+       if (unlikely(!skb))
+               return;
+
+       if (sk && mptcp_reconstruct_mapping(skb, orig_skb)) {
+               __kfree_skb(skb);
+               return;
+       }
+
+       skb->sk = meta_sk;
+
+       /* If it reached already the destination, we don't have to reinject it */
+       if (!after(TCP_SKB_CB(skb)->end_seq, meta_tp->snd_una)) {
+               __kfree_skb(skb);
+               return;
+       }
+
+       /* Only reinject segments that are fully covered by the mapping */
+       if (skb->len + (mptcp_is_data_fin(skb) ? 1 : 0) !=
+           TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq) {
+               u32 seq = TCP_SKB_CB(skb)->seq;
+               u32 end_seq = TCP_SKB_CB(skb)->end_seq;
+
+               __kfree_skb(skb);
+
+               /* Ok, now we have to look for the full mapping in the meta
+                * send-queue :S
+                */
+               tcp_for_write_queue(skb, meta_sk) {
+                       /* Not yet at the mapping? */
+                       if (before(TCP_SKB_CB(skb)->seq, seq))
+                               continue;
+                       /* We have passed by the mapping */
+                       if (after(TCP_SKB_CB(skb)->end_seq, end_seq))
+                               return;
+
+                       __mptcp_reinject_data(skb, meta_sk, NULL, 1);
+               }
+               return;
+       }
+
+       /* If it's empty, just add */
+       if (skb_queue_empty(&mpcb->reinject_queue)) {
+               skb_queue_head(&mpcb->reinject_queue, skb);
+               return;
+       }
+
+       /* Find place to insert skb - or even we can 'drop' it, as the
+        * data is already covered by other skb's in the reinject-queue.
+        *
+        * This is inspired by code from tcp_data_queue.
+        */
+
+       skb1 = skb_peek_tail(&mpcb->reinject_queue);
+       seq = TCP_SKB_CB(skb)->seq;
+       while (1) {
+               if (!after(TCP_SKB_CB(skb1)->seq, seq))
+                       break;
+               if (skb_queue_is_first(&mpcb->reinject_queue, skb1)) {
+                       skb1 = NULL;
+                       break;
+               }
+               skb1 = skb_queue_prev(&mpcb->reinject_queue, skb1);
+       }
+
+       /* Do skb overlap to previous one? */
+       end_seq = TCP_SKB_CB(skb)->end_seq;
+       if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) {
+               if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
+                       /* All the bits are present. Don't reinject */
+                       __kfree_skb(skb);
+                       return;
+               }
+               if (seq == TCP_SKB_CB(skb1)->seq) {
+                       if (skb_queue_is_first(&mpcb->reinject_queue, skb1))
+                               skb1 = NULL;
+                       else
+                               skb1 = skb_queue_prev(&mpcb->reinject_queue, skb1);
+               }
+       }
+       if (!skb1)
+               __skb_queue_head(&mpcb->reinject_queue, skb);
+       else
+               __skb_queue_after(&mpcb->reinject_queue, skb1, skb);
+
+       /* And clean segments covered by new one as whole. */
+       while (!skb_queue_is_last(&mpcb->reinject_queue, skb)) {
+               skb1 = skb_queue_next(&mpcb->reinject_queue, skb);
+
+               if (!after(end_seq, TCP_SKB_CB(skb1)->seq))
+                       break;
+
+               __skb_unlink(skb1, &mpcb->reinject_queue);
+               __kfree_skb(skb1);
+       }
+       return;
+}
+
+/* Inserts data into the reinject queue */
+void mptcp_reinject_data(struct sock *sk, int clone_it)
+{
+       struct sk_buff *skb_it, *tmp;
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = tp->meta_sk;
+
+       /* It has already been closed - there is really no point in reinjecting */
+       if (meta_sk->sk_state == TCP_CLOSE)
+               return;
+
+       skb_queue_walk_safe(&sk->sk_write_queue, skb_it, tmp) {
+               struct tcp_skb_cb *tcb = TCP_SKB_CB(skb_it);
+               /* Subflow syn's and fin's are not reinjected.
+                *
+                * As well as empty subflow-fins with a data-fin.
+                * They are reinjected below (without the subflow-fin-flag)
+                */
+               if (tcb->tcp_flags & TCPHDR_SYN ||
+                   (tcb->tcp_flags & TCPHDR_FIN && !mptcp_is_data_fin(skb_it)) ||
+                   (tcb->tcp_flags & TCPHDR_FIN && mptcp_is_data_fin(skb_it) && !skb_it->len))
+                       continue;
+
+               __mptcp_reinject_data(skb_it, meta_sk, sk, clone_it);
+       }
+
+       skb_it = tcp_write_queue_tail(meta_sk);
+       /* If sk has sent the empty data-fin, we have to reinject it too. */
+       if (skb_it && mptcp_is_data_fin(skb_it) && skb_it->len == 0 &&
+           TCP_SKB_CB(skb_it)->path_mask & mptcp_pi_to_flag(tp->mptcp->path_index)) {
+               __mptcp_reinject_data(skb_it, meta_sk, NULL, 1);
+       }
+
+       mptcp_push_pending_frames(meta_sk);
+
+       tp->pf = 1;
+}
+EXPORT_SYMBOL(mptcp_reinject_data);
+
+static void mptcp_combine_dfin(struct sk_buff *skb, struct sock *meta_sk,
+                              struct sock *subsk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       struct sock *sk_it;
+       int all_empty = 1, all_acked;
+
+       /* In infinite mapping we always try to combine */
+       if (mpcb->infinite_mapping_snd && tcp_close_state(subsk)) {
+               subsk->sk_shutdown |= SEND_SHUTDOWN;
+               TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_FIN;
+               return;
+       }
+
+       /* Don't combine, if they didn't combine - otherwise we end up in
+        * TIME_WAIT, even if our app is smart enough to avoid it
+        */
+       if (meta_sk->sk_shutdown & RCV_SHUTDOWN) {
+               if (!mpcb->dfin_combined)
+                       return;
+       }
+
+       /* If no other subflow has data to send, we can combine */
+       mptcp_for_each_sk(mpcb, sk_it) {
+               if (!mptcp_sk_can_send(sk_it))
+                       continue;
+
+               if (!tcp_write_queue_empty(sk_it))
+                       all_empty = 0;
+       }
+
+       /* If all data has been DATA_ACKed, we can combine.
+        * -1, because the data_fin consumed one byte
+        */
+       all_acked = (meta_tp->snd_una == (meta_tp->write_seq - 1));
+
+       if ((all_empty || all_acked) && tcp_close_state(subsk)) {
+               subsk->sk_shutdown |= SEND_SHUTDOWN;
+               TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_FIN;
+       }
+}
+
+static struct sk_buff *mptcp_skb_entail(struct sock *sk, struct sk_buff *skb,
+                                       int reinject)
+{
+       __be32 *ptr;
+       __u16 data_len;
+       struct mp_dss *mdss;
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+       struct mptcp_cb *mpcb = tp->mpcb;
+       struct tcp_skb_cb *tcb;
+       struct sk_buff *subskb = NULL;
+
+       if (!reinject)
+               TCP_SKB_CB(skb)->mptcp_flags |= (mpcb->snd_hiseq_index ?
+                                                 MPTCPHDR_SEQ64_INDEX : 0);
+
+       subskb = mptcp_pskb_copy(skb);
+       if (!subskb)
+               return NULL;
+
+       TCP_SKB_CB(skb)->path_mask |= mptcp_pi_to_flag(tp->mptcp->path_index);
+
+       if (!(sk->sk_route_caps & NETIF_F_ALL_CSUM) &&
+           skb->ip_summed == CHECKSUM_PARTIAL) {
+               subskb->csum = skb->csum = skb_checksum(skb, 0, skb->len, 0);
+               subskb->ip_summed = skb->ip_summed = CHECKSUM_NONE;
+       }
+
+       /* The subskb is going in the subflow send-queue. Its path-mask
+        * is not needed anymore and MUST be set to 0, as the path-mask
+        * is a union with inet_skb_param.
+        */
+       tcb = TCP_SKB_CB(subskb);
+       tcb->path_mask = 0;
+
+       if (mptcp_is_data_fin(subskb))
+               mptcp_combine_dfin(subskb, meta_sk, sk);
+
+       if (tp->mpcb->infinite_mapping_snd)
+               goto no_data_seq;
+
+       if (tp->mpcb->send_infinite_mapping &&
+           !before(tcb->seq, mptcp_meta_tp(tp)->snd_nxt)) {
+               tp->mptcp->fully_established = 1;
+               tp->mpcb->infinite_mapping_snd = 1;
+               tp->mptcp->infinite_cutoff_seq = tp->write_seq;
+               tcb->mptcp_flags |= MPTCPHDR_INF;
+               data_len = 0;
+       } else {
+               data_len = tcb->end_seq - tcb->seq;
+       }
+
+       /**** Write MPTCP DSS-option to the packet. ****/
+       ptr = (__be32 *)(subskb->data - (MPTCP_SUB_LEN_DSS_ALIGN +
+                                     MPTCP_SUB_LEN_ACK_ALIGN +
+                                     MPTCP_SUB_LEN_SEQ_ALIGN));
+
+       /* Then we start writing it from the start */
+       mdss = (struct mp_dss *)ptr;
+
+       mdss->kind = TCPOPT_MPTCP;
+       mdss->sub = MPTCP_SUB_DSS;
+       mdss->rsv1 = 0;
+       mdss->rsv2 = 0;
+       mdss->F = (mptcp_is_data_fin(subskb) ? 1 : 0);
+       mdss->m = 0;
+       mdss->M = 1;
+       mdss->a = 0;
+       mdss->A = 1;
+       mdss->len = mptcp_sub_len_dss(mdss, tp->mpcb->dss_csum);
+
+       ptr++;
+       ptr++; /* data_ack will be set in mptcp_options_write */
+       *ptr++ = htonl(tcb->seq); /* data_seq */
+
+       /* If it's a non-data DATA_FIN, we set subseq to 0 (draft v7) */
+       if (mptcp_is_data_fin(subskb) && subskb->len == 0)
+               *ptr++ = 0; /* subseq */
+       else
+               *ptr++ = htonl(tp->write_seq - tp->mptcp->snt_isn); /* subseq */
+
+       if (tp->mpcb->dss_csum && data_len) {
+               __be16 *p16 = (__be16 *)ptr;
+               __be32 hdseq = mptcp_get_highorder_sndbits(subskb, tp->mpcb);
+               __wsum csum;
+               *ptr = htonl(((data_len) << 16) |
+                               (TCPOPT_EOL << 8) |
+                               (TCPOPT_EOL));
+
+               csum = csum_partial(ptr - 2, 12, subskb->csum);
+               p16++;
+               *p16++ = csum_fold(csum_partial(&hdseq, sizeof(hdseq), csum));
+       } else {
+               *ptr++ = htonl(((data_len) << 16) |
+                               (TCPOPT_NOP << 8) |
+                               (TCPOPT_NOP));
+       }
+
+no_data_seq:
+       tcb->seq = tp->write_seq;
+       tcb->sacked = 0; /* reset the sacked field: from the point of view
+                         * of this subflow, we are sending a brand new
+                         * segment */
+       /* Take into account seg len */
+       tp->write_seq += subskb->len + ((tcb->tcp_flags & TCPHDR_FIN) ? 1 : 0);
+       tcb->end_seq = tp->write_seq;
+
+       /* If it's a non-payload DATA_FIN (also no subflow-fin), the
+        * segment is not part of the subflow but on a meta-only-level
+        */
+       if (!mptcp_is_data_fin(subskb) || tcb->end_seq != tcb->seq) {
+               tcp_add_write_queue_tail(sk, subskb);
+               sk->sk_wmem_queued += subskb->truesize;
+               sk_mem_charge(sk, subskb->truesize);
+       }
+
+       return subskb;
+}
+
+static void mptcp_sub_event_new_data_sent(struct sock *sk,
+                                         struct sk_buff *subskb,
+                                         struct sk_buff *skb)
+{
+       /* If it's a non-payload DATA_FIN (also no subflow-fin), the
+        * segment is not part of the subflow but on a meta-only-level
+        *
+        * We free it, because it has been queued nowhere.
+        */
+       if (!mptcp_is_data_fin(subskb) ||
+           (TCP_SKB_CB(subskb)->end_seq != TCP_SKB_CB(subskb)->seq)) {
+               tcp_event_new_data_sent(sk, subskb);
+               tcp_sk(sk)->mptcp->second_packet = 1;
+               tcp_sk(sk)->mptcp->last_end_data_seq = TCP_SKB_CB(skb)->end_seq;
+       } else {
+               kfree_skb(subskb);
+       }
+}
+
+/* Handle the packets and sockets after a tcp_transmit_skb failed */
+static void mptcp_transmit_skb_failed(struct sock *sk, struct sk_buff *skb,
+                                     struct sk_buff *subskb)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct mptcp_cb *mpcb = tp->mpcb;
+
+       /* No work to do if we are in infinite mapping mode
+        * There is only one subflow left and we cannot send this segment on
+        * another subflow.
+        */
+       if (mpcb->infinite_mapping_snd)
+               return;
+
+       TCP_SKB_CB(skb)->path_mask &= ~mptcp_pi_to_flag(tp->mptcp->path_index);
+
+       if (TCP_SKB_CB(subskb)->tcp_flags & TCPHDR_FIN) {
+               /* If it is a subflow-fin we must leave it on the
+                * subflow-send-queue, so that the probe-timer
+                * can retransmit it.
+                */
+               if (!tp->packets_out && !inet_csk(sk)->icsk_pending)
+                       inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
+                                                 inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
+       } else if (mptcp_is_data_fin(subskb) &&
+                  TCP_SKB_CB(subskb)->end_seq == TCP_SKB_CB(subskb)->seq) {
+               /* An empty data-fin has not been enqueued on the subflow
+                * and thus we free it.
+                */
+
+               kfree_skb(subskb);
+       } else {
+               /* In all other cases we remove it from the sub-queue.
+                * Other subflows may send it, or the probe-timer will
+                * handle it.
+                */
+               tcp_advance_send_head(sk, subskb);
+
+               /* tcp_add_write_queue_tail initialized highest_sack. We have
+                * to reset it, if necessary.
+                */
+               if (tp->highest_sack == subskb)
+                       tp->highest_sack = NULL;
+
+               tcp_unlink_write_queue(subskb, sk);
+               tp->write_seq -= subskb->len;
+               sk_wmem_free_skb(sk, subskb);
+       }
+}
+
+/* Function to create two new TCP segments.  Shrinks the given segment
+ * to the specified size and appends a new segment with the rest of the
+ * packet to the list.  This won't be called frequently, I hope.
+ * Remember, these are still headerless SKBs at this point.
+ */
+int mptcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
+                  unsigned int mss_now, int reinject)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct sk_buff *buff;
+       int nsize, old_factor;
+       int nlen;
+       u8 flags;
+       int dsslen = MPTCP_SUB_LEN_DSS_ALIGN + MPTCP_SUB_LEN_ACK_ALIGN +
+                    MPTCP_SUB_LEN_SEQ_ALIGN;
+       char dss[MPTCP_SUB_LEN_DSS_ALIGN + MPTCP_SUB_LEN_ACK_ALIGN +
+                MPTCP_SUB_LEN_SEQ_ALIGN];
+
+       if (WARN_ON(len > skb->len))
+               return -EINVAL;
+
+       /* DSS-option must be recovered afterwards. */
+       if (!is_meta_sk(sk))
+               memcpy(dss, skb->data - dsslen, dsslen);
+
+       nsize = skb_headlen(skb) - len;
+       if (nsize < 0)
+               nsize = 0;
+
+       if (skb_cloned(skb)) {
+               if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+                       return -ENOMEM;
+               /* Recover dss-option */
+               if (!is_meta_sk(sk))
+                       memcpy(skb->data - dsslen, dss, dsslen);
+       }
+
+       /* Get a new skb... force flag on. */
+       buff = sk_stream_alloc_skb(sk, nsize, GFP_ATOMIC);
+       if (buff == NULL)
+               return -ENOMEM; /* We'll just try again later. */
+
+       /* See below - if reinject == 1, the buff will be added to the reinject-
+        * queue, which is currently not part of the memory-accounting.
+        */
+       if (reinject != 1) {
+               sk->sk_wmem_queued += buff->truesize;
+               sk_mem_charge(sk, buff->truesize);
+       }
+       nlen = skb->len - len - nsize;
+       buff->truesize += nlen;
+       skb->truesize -= nlen;
+
+       /* Correct the sequence numbers. */
+       TCP_SKB_CB(buff)->seq = TCP_SKB_CB(skb)->seq + len;
+       TCP_SKB_CB(buff)->end_seq = TCP_SKB_CB(skb)->end_seq;
+       TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(buff)->seq;
+
+       /* PSH and FIN should only be set in the second packet. */
+       flags = TCP_SKB_CB(skb)->tcp_flags;
+       TCP_SKB_CB(skb)->tcp_flags = flags & ~(TCPHDR_FIN | TCPHDR_PSH);
+       TCP_SKB_CB(buff)->tcp_flags = flags;
+       TCP_SKB_CB(buff)->sacked = TCP_SKB_CB(skb)->sacked;
+
+       flags = TCP_SKB_CB(skb)->mptcp_flags;
+       TCP_SKB_CB(skb)->mptcp_flags = flags & ~(MPTCPHDR_FIN);
+       TCP_SKB_CB(buff)->mptcp_flags = flags;
+
+       if (!skb_shinfo(skb)->nr_frags && skb->ip_summed != CHECKSUM_PARTIAL) {
+               /* Copy and checksum data tail into the new buffer. */
+               buff->csum = csum_partial_copy_nocheck(skb->data + len,
+                                                      skb_put(buff, nsize),
+                                                      nsize, 0);
+
+               skb_trim(skb, len);
+
+               skb->csum = csum_block_sub(skb->csum, buff->csum, len);
+       } else {
+               skb->ip_summed = CHECKSUM_PARTIAL;
+               skb_split(skb, buff, len);
+       }
+
+       /* We lost the dss-option when creating buff - put it back! */
+       if (!is_meta_sk(sk))
+               memcpy(buff->data - dsslen, dss, dsslen);
+
+       buff->ip_summed = skb->ip_summed;
+
+       /* Looks stupid, but our code really uses when of
+        * skbs, which it never sent before. --ANK
+        */
+       TCP_SKB_CB(buff)->when = TCP_SKB_CB(skb)->when;
+       buff->tstamp = skb->tstamp;
+
+       old_factor = tcp_skb_pcount(skb);
+
+       /* Fix up tso_factor for both original and new SKB.  */
+       tcp_set_skb_tso_segs(sk, skb, mss_now);
+       tcp_set_skb_tso_segs(sk, buff, mss_now);
+
+       /* If this packet has been sent out already, we must
+        * adjust the various packet counters.
+        */
+       if (!before(tp->snd_nxt, TCP_SKB_CB(buff)->end_seq) && reinject != 1) {
+               int diff = old_factor - tcp_skb_pcount(skb) -
+                       tcp_skb_pcount(buff);
+
+               if (diff)
+                       tcp_adjust_pcount(sk, skb, diff);
+       }
+
+       /* Link BUFF into the send queue. */
+       skb_header_release(buff);
+       if (reinject == 1)
+               __skb_queue_after(&tcp_sk(sk)->mpcb->reinject_queue, skb, buff);
+       else
+               tcp_insert_write_queue_after(skb, buff, sk);
+
+       return 0;
+}
+
+int mptso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
+                  unsigned int mss_now, gfp_t gfp, int reinject)
+{
+       struct sk_buff *buff;
+       int nlen = skb->len - len, old_factor;
+       u8 flags;
+       int dsslen = MPTCP_SUB_LEN_DSS_ALIGN + MPTCP_SUB_LEN_ACK_ALIGN +
+                    MPTCP_SUB_LEN_SEQ_ALIGN;
+
+       /* All of a TSO frame must be composed of paged data.  */
+       if (skb->len != skb->data_len)
+               return mptcp_fragment(sk, skb, len, mss_now, reinject);
+
+       buff = sk_stream_alloc_skb(sk, 0, gfp);
+       if (unlikely(buff == NULL))
+               return -ENOMEM;
+
+       /* See below - if reinject == 1, the buff will be added to the reinject-
+        * queue, which is currently not part of the memory-accounting.
+        */
+       if (reinject != 1) {
+               sk->sk_wmem_queued += buff->truesize;
+               sk_mem_charge(sk, buff->truesize);
+       }
+       buff->truesize += nlen;
+       skb->truesize -= nlen;
+
+       /* Correct the sequence numbers. */
+       TCP_SKB_CB(buff)->seq = TCP_SKB_CB(skb)->seq + len;
+       TCP_SKB_CB(buff)->end_seq = TCP_SKB_CB(skb)->end_seq;
+       TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(buff)->seq;
+
+       /* PSH and FIN should only be set in the second packet. */
+       flags = TCP_SKB_CB(skb)->tcp_flags;
+       TCP_SKB_CB(skb)->tcp_flags = flags & ~(TCPHDR_FIN | TCPHDR_PSH);
+       TCP_SKB_CB(buff)->tcp_flags = flags;
+
+       flags = TCP_SKB_CB(skb)->mptcp_flags;
+       TCP_SKB_CB(skb)->mptcp_flags = flags & ~(MPTCPHDR_FIN);
+       TCP_SKB_CB(buff)->mptcp_flags = flags;
+
+       /* This packet was never sent out yet, so no SACK bits. */
+       TCP_SKB_CB(buff)->sacked = 0;
+
+       buff->ip_summed = CHECKSUM_PARTIAL;
+       skb->ip_summed = CHECKSUM_PARTIAL;
+       skb_split(skb, buff, len);
+
+       /* We lost the dss-option when creating buff - put it back! */
+       if (!is_meta_sk(sk))
+               memcpy(buff->data - dsslen, skb->data - dsslen, dsslen);
+
+       old_factor = tcp_skb_pcount(skb);
+
+       /* Fix up tso_factor for both original and new SKB.  */
+       tcp_set_skb_tso_segs(sk, skb, mss_now);
+       tcp_set_skb_tso_segs(sk, buff, mss_now);
+
+       /* If this packet has been sent out already, we must
+        * adjust the various packet counters.
+        */
+       if (!before(tcp_sk(sk)->snd_nxt, TCP_SKB_CB(buff)->end_seq) && reinject != 1) {
+               int diff = old_factor - tcp_skb_pcount(skb) -
+                       tcp_skb_pcount(buff);
+
+               if (diff)
+                       tcp_adjust_pcount(sk, skb, diff);
+       }
+
+       /* Link BUFF into the send queue. */
+       skb_header_release(buff);
+       if (reinject == 1)
+               __skb_queue_after(&tcp_sk(sk)->mpcb->reinject_queue, skb, buff);
+       else
+               tcp_insert_write_queue_after(skb, buff, sk);
+
+       return 0;
+}
+
+/* Inspired by tcp_write_wakeup */
+int mptcp_write_wakeup(struct sock *meta_sk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sk_buff *skb, *subskb;
+
+       skb = tcp_send_head(meta_sk);
+       if (skb &&
+           before(TCP_SKB_CB(skb)->seq, tcp_wnd_end(meta_tp))) {
+               int err;
+               unsigned int mss;
+               unsigned int seg_size = tcp_wnd_end(meta_tp) - TCP_SKB_CB(skb)->seq;
+               struct sock *subsk = get_available_subflow(meta_sk, skb, &mss);
+               if (!subsk)
+                       return -1;
+
+               if (before(meta_tp->pushed_seq, TCP_SKB_CB(skb)->end_seq))
+                       meta_tp->pushed_seq = TCP_SKB_CB(skb)->end_seq;
+
+               /* We are probing the opening of a window
+                * but the window size is != 0
+                * must have been a result SWS avoidance ( sender )
+                */
+               if (seg_size < TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq ||
+                   skb->len > mss) {
+                       seg_size = min(seg_size, mss);
+                       TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
+                       if (mptcp_fragment(meta_sk, skb, seg_size, mss, 0))
+                               return -1;
+               } else if (!tcp_skb_pcount(skb)) {
+                       tcp_set_skb_tso_segs(meta_sk, skb, mss);
+               }
+
+               subskb = mptcp_skb_entail(subsk, skb, 0);
+               if (!subskb)
+                       return -1;
+
+               TCP_SKB_CB(subskb)->tcp_flags |= TCPHDR_PSH;
+               TCP_SKB_CB(skb)->when = tcp_time_stamp;
+               TCP_SKB_CB(subskb)->when = tcp_time_stamp;
+               err = tcp_transmit_skb(subsk, subskb, 1, GFP_ATOMIC);
+               if (unlikely(err)) {
+                       mptcp_transmit_skb_failed(subsk, skb, subskb);
+                       return err;
+               }
+
+               mptcp_check_sndseq_wrap(meta_tp, TCP_SKB_CB(skb)->end_seq -
+                                                TCP_SKB_CB(skb)->seq);
+               tcp_event_new_data_sent(meta_sk, skb);
+               mptcp_sub_event_new_data_sent(subsk, subskb, skb);
+
+               return 0;
+       } else {
+               struct sock *sk_it;
+               int ans = 0;
+
+               if (between(meta_tp->snd_up, meta_tp->snd_una + 1,
+                           meta_tp->snd_una + 0xFFFF)) {
+                       mptcp_for_each_sk(meta_tp->mpcb, sk_it) {
+                               if (mptcp_sk_can_send_ack(sk_it))
+                                       tcp_xmit_probe_skb(sk_it, 1);
+                       }
+               }
+
+               /* At least one of the tcp_xmit_probe_skb's has to succeed */
+               mptcp_for_each_sk(meta_tp->mpcb, sk_it) {
+                       int ret;
+
+                       if (!mptcp_sk_can_send_ack(sk_it))
+                               continue;
+
+                       ret = tcp_xmit_probe_skb(sk_it, 0);
+                       if (unlikely(ret > 0))
+                               ans = ret;
+               }
+               return ans;
+       }
+}
+
+static void mptcp_find_and_set_pathmask(struct sock *meta_sk, struct sk_buff *skb)
+{
+       struct sk_buff *skb_it;
+
+       skb_it = tcp_write_queue_head(meta_sk);
+
+       tcp_for_write_queue_from(skb_it, meta_sk) {
+               if (skb_it == tcp_send_head(meta_sk))
+                       break;
+
+               if (TCP_SKB_CB(skb_it)->seq == TCP_SKB_CB(skb)->seq) {
+                       TCP_SKB_CB(skb)->path_mask = TCP_SKB_CB(skb_it)->path_mask;
+                       break;
+               }
+       }
+}
+
+static struct sk_buff *mptcp_rcv_buf_optimization(struct sock *sk, int penal)
+{
+       struct sock *meta_sk;
+       struct tcp_sock *tp = tcp_sk(sk), *tp_it;
+       struct sk_buff *skb_head;
+
+       if (tp->mpcb->cnt_subflows == 1)
+               return NULL;
+
+       meta_sk = mptcp_meta_sk(sk);
+       skb_head = tcp_write_queue_head(meta_sk);
+
+       if (!skb_head || skb_head == tcp_send_head(meta_sk))
+               return NULL;
+
+       /* If penalization is optional (coming from mptcp_next_segment() and
+        * We are not send-buffer-limited we do not penalize. The retransmission
+        * is just an optimization to fix the idle-time due to the delay before
+        * we wake up the application.
+        */
+       if (!penal && sk_stream_memory_free(meta_sk))
+               goto retrans;
+
+       /* Only penalize again after an RTT has elapsed */
+       if (tcp_time_stamp - tp->mptcp->last_rbuf_opti < tp->srtt >> 3)
+               goto retrans;
+
+       /* Half the cwnd of the slow flow */
+       mptcp_for_each_tp(tp->mpcb, tp_it) {
+               if (tp_it != tp &&
+                   TCP_SKB_CB(skb_head)->path_mask & mptcp_pi_to_flag(tp_it->mptcp->path_index)) {
+                       if (tp->srtt < tp_it->srtt && inet_csk((struct sock *)tp_it)->icsk_ca_state == TCP_CA_Open) {
+                               tp_it->snd_cwnd = max(tp_it->snd_cwnd >> 1U, 1U);
+                               if (tp_it->snd_ssthresh != TCP_INFINITE_SSTHRESH)
+                                       tp_it->snd_ssthresh = max(tp_it->snd_ssthresh >> 1U, 2U);
+
+                               tp->mptcp->last_rbuf_opti = tcp_time_stamp;
+                       }
+                       break;
+               }
+       }
+
+retrans:
+
+       /* Segment not yet injected into this path? Take it!!! */
+       if (!(TCP_SKB_CB(skb_head)->path_mask & mptcp_pi_to_flag(tp->mptcp->path_index))) {
+               bool do_retrans = false;
+               mptcp_for_each_tp(tp->mpcb, tp_it) {
+                       if (tp_it != tp &&
+                           TCP_SKB_CB(skb_head)->path_mask & mptcp_pi_to_flag(tp_it->mptcp->path_index)) {
+                               if (tp_it->snd_cwnd <= 4) {
+                                       do_retrans = true;
+                                       break;
+                               }
+
+                               if (4 * tp->srtt >= tp_it->srtt) {
+                                       do_retrans = false;
+                                       break;
+                               } else {
+                                       do_retrans = true;
+                               }
+                       }
+               }
+
+               if (do_retrans)
+                       return skb_head;
+       }
+       return NULL;
+}
+
+int mptcp_write_xmit(struct sock *meta_sk, unsigned int mss_now, int nonagle,
+                    int push_one, gfp_t gfp)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk), *subtp;
+       struct sock *subsk;
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       struct sk_buff *skb;
+       unsigned int tso_segs, old_factor, sent_pkts;
+       int cwnd_quota;
+       int result;
+       int reinject = 0;
+
+       sent_pkts = 0;
+
+       /* Currently mtu-probing is not done in MPTCP */
+       if (!push_one && 0) {
+               /* Do MTU probing. */
+               result = tcp_mtu_probe(meta_sk);
+               if (!result)
+                       return 0;
+               else if (result > 0)
+                       sent_pkts = 1;
+       }
+
+       while ((skb = mptcp_next_segment(meta_sk, &reinject))) {
+               unsigned int limit;
+               struct sk_buff *subskb = NULL;
+               u32 noneligible = mpcb->noneligible;
+
+               if (reinject == 1) {
+                       if (!after(TCP_SKB_CB(skb)->end_seq, meta_tp->snd_una)) {
+                               /* Segment already reached the peer, take the next one */
+                               __skb_unlink(skb, &mpcb->reinject_queue);
+                               __kfree_skb(skb);
+                               continue;
+                       }
+
+                       /* Reinjection and it is coming from a subflow? We need
+                        * to find out the path-mask from the meta-write-queue
+                        * to properly select a subflow.
+                        */
+                       if (!TCP_SKB_CB(skb)->path_mask)
+                               mptcp_find_and_set_pathmask(meta_sk, skb);
+               }
+
+subflow:
+               subsk = get_available_subflow(meta_sk, skb, &mss_now);
+               if (!subsk)
+                       break;
+               subtp = tcp_sk(subsk);
+
+               /* Since all subsocks are locked before calling the scheduler,
+                * the tcp_send_head should not change.
+                */
+               BUG_ON(!reinject && tcp_send_head(meta_sk) != skb);
+retry:
+               /* If the segment was cloned (e.g. a meta retransmission),
+                * the header must be expanded/copied so that there is no
+                * corruption of TSO information.
+                */
+               if (skb_unclone(skb, GFP_ATOMIC))
+                       break;
+
+               old_factor = tcp_skb_pcount(skb);
+               tcp_set_skb_tso_segs(meta_sk, skb, mss_now);
+               tso_segs = tcp_skb_pcount(skb);
+
+               if (reinject == -1) {
+                       /* The packet has already once been sent, so if we
+                        * change the pcount here we have to adjust packets_out
+                        * in the meta-sk
+                        */
+                       int diff = old_factor - tso_segs;
+
+                       if (diff)
+                               tcp_adjust_pcount(meta_sk, skb, diff);
+               }
+
+               cwnd_quota = tcp_cwnd_test(subtp, skb);
+               if (!cwnd_quota) {
+                       /* May happen due to two cases:
+                        *
+                        * - if at the first selection we circumvented
+                        *   the test due to a DATA_FIN (and got rejected at
+                        *   tcp_snd_wnd_test), but the reinjected segment is not
+                        *   a DATA_FIN.
+                        * - if we take a DATA_FIN with data, but
+                        *   tcp_set_skb_tso_segs() increases the number of
+                        *   tso_segs to something > 1. Then, cwnd_test might
+                        *   reject it.
+                        */
+                       mpcb->noneligible |= mptcp_pi_to_flag(subtp->mptcp->path_index);
+                       continue;
+               }
+
+               if (!reinject && unlikely(!tcp_snd_wnd_test(meta_tp, skb, mss_now))) {
+                       skb = mptcp_rcv_buf_optimization(subsk, 1);
+                       if (skb) {
+                               reinject = -1;
+                               goto retry;
+                       }
+                       break;
+               }
+
+               if (tso_segs == 1) {
+                       if (unlikely(!tcp_nagle_test(meta_tp, skb, mss_now,
+                                                    (tcp_skb_is_last(meta_sk, skb) ?
+                                                     nonagle : TCP_NAGLE_PUSH))))
+                               break;
+               } else {
+                       /* Do not try to defer the transmission of a reinjected
+                        * segment. Send it directly.
+                        * If it is not possible to send the TSO segment on the
+                        * best subflow right now try to look for another subflow.
+                        * If there is no subflow available defer the segment to avoid
+                        * the call to mptso_fragment.
+                        */
+                       if (!push_one && !reinject && tcp_tso_should_defer(subsk, skb)) {
+                               mpcb->noneligible |= mptcp_pi_to_flag(subtp->mptcp->path_index);
+                               goto subflow;
+                       }
+               }
+
+               limit = mss_now;
+               if (tso_segs > 1 && !tcp_urg_mode(meta_tp))
+                       limit = tcp_mss_split_point(subsk, skb, mss_now,
+                                                   min_t(unsigned int,
+                                                         cwnd_quota,
+                                                         subsk->sk_gso_max_segs),
+                                                   nonagle);
+
+               if (skb->len > limit &&
+                   unlikely(mptso_fragment(meta_sk, skb, limit, mss_now, gfp, reinject)))
+                       break;
+
+               subskb = mptcp_skb_entail(subsk, skb, reinject);
+               if (!subskb)
+                       break;
+
+               mpcb->noneligible = noneligible;
+               TCP_SKB_CB(skb)->when = tcp_time_stamp;
+               TCP_SKB_CB(subskb)->when = tcp_time_stamp;
+               if (unlikely(tcp_transmit_skb(subsk, subskb, 1, gfp))) {
+                       mptcp_transmit_skb_failed(subsk, skb, subskb);
+                       mpcb->noneligible |= mptcp_pi_to_flag(subtp->mptcp->path_index);
+                       continue;
+               }
+
+               if (!reinject) {
+                       mptcp_check_sndseq_wrap(meta_tp,
+                                               TCP_SKB_CB(skb)->end_seq -
+                                               TCP_SKB_CB(skb)->seq);
+                       tcp_event_new_data_sent(meta_sk, skb);
+               }
+
+               tcp_minshall_update(meta_tp, mss_now, skb);
+               sent_pkts += tcp_skb_pcount(skb);
+               tcp_sk(subsk)->mptcp->sent_pkts += tcp_skb_pcount(skb);
+
+               mptcp_sub_event_new_data_sent(subsk, subskb, skb);
+
+               if (reinject > 0) {
+                       __skb_unlink(skb, &mpcb->reinject_queue);
+                       kfree_skb(skb);
+               }
+
+               if (push_one)
+                       break;
+       }
+
+       mpcb->noneligible = 0;
+
+       if (likely(sent_pkts)) {
+               mptcp_for_each_sk(mpcb, subsk) {
+                       subtp = tcp_sk(subsk);
+                       if (subtp->mptcp->sent_pkts) {
+                               if (tcp_in_cwnd_reduction(subsk))
+                                       subtp->prr_out += subtp->mptcp->sent_pkts;
+                               tcp_cwnd_validate(subsk);
+                               subtp->mptcp->sent_pkts = 0;
+                       }
+               }
+               return 0;
+       }
+
+       return !meta_tp->packets_out && tcp_send_head(meta_sk);
+}
+
+void mptcp_write_space(struct sock *sk)
+{
+       mptcp_push_pending_frames(mptcp_meta_sk(sk));
+}
+
+u32 __mptcp_select_window(struct sock *sk)
+{
+       struct inet_connection_sock *icsk = inet_csk(sk);
+       struct tcp_sock *tp = tcp_sk(sk), *meta_tp = mptcp_meta_tp(tp);
+       int mss, free_space, full_space, window;
+
+       /* MSS for the peer's data.  Previous versions used mss_clamp
+        * here.  I don't know if the value based on our guesses
+        * of peer's MSS is better for the performance.  It's more correct
+        * but may be worse for the performance because of rcv_mss
+        * fluctuations.  --SAW  1998/11/1
+        */
+       mss = icsk->icsk_ack.rcv_mss;
+       free_space = tcp_space(sk);
+       full_space = min_t(int, meta_tp->window_clamp,
+                       tcp_full_space(sk));
+
+       if (mss > full_space)
+               mss = full_space;
+
+       if (free_space < (full_space >> 1)) {
+               icsk->icsk_ack.quick = 0;
+
+               if (tcp_memory_pressure)
+                       /* TODO this has to be adapted when we support different
+                        * MSS's among the subflows.
+                        */
+                       meta_tp->rcv_ssthresh = min(meta_tp->rcv_ssthresh,
+                                                   4U * meta_tp->advmss);
+
+               if (free_space < mss)
+                       return 0;
+       }
+
+       if (free_space > meta_tp->rcv_ssthresh)
+               free_space = meta_tp->rcv_ssthresh;
+
+       /* Don't do rounding if we are using window scaling, since the
+        * scaled window will not line up with the MSS boundary anyway.
+        */
+       window = meta_tp->rcv_wnd;
+       if (tp->rx_opt.rcv_wscale) {
+               window = free_space;
+
+               /* Advertise enough space so that it won't get scaled away.
+                * Import case: prevent zero window announcement if
+                * 1<<rcv_wscale > mss.
+                */
+               if (((window >> tp->rx_opt.rcv_wscale) << tp->
+                    rx_opt.rcv_wscale) != window)
+                       window = (((window >> tp->rx_opt.rcv_wscale) + 1)
+                                 << tp->rx_opt.rcv_wscale);
+       } else {
+               /* Get the largest window that is a nice multiple of mss.
+                * Window clamp already applied above.
+                * If our current window offering is within 1 mss of the
+                * free space we just keep it. This prevents the divide
+                * and multiply from happening most of the time.
+                * We also don't do any window rounding when the free space
+                * is too small.
+                */
+               if (window <= free_space - mss || window > free_space)
+                       window = (free_space / mss) * mss;
+               else if (mss == full_space &&
+                        free_space > window + (full_space >> 1))
+                       window = free_space;
+       }
+
+       return window;
+}
+
+void mptcp_syn_options(struct sock *sk, struct tcp_out_options *opts,
+                      unsigned *remaining)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       opts->options |= OPTION_MPTCP;
+       if (is_master_tp(tp)) {
+               opts->mptcp_options |= OPTION_MP_CAPABLE | OPTION_TYPE_SYN;
+               *remaining -= MPTCP_SUB_LEN_CAPABLE_SYN_ALIGN;
+               opts->mp_capable.sender_key = tp->mptcp_loc_key;
+               opts->dss_csum = !!sysctl_mptcp_checksum;
+       } else {
+               struct mptcp_cb *mpcb = tp->mpcb;
+
+               opts->mptcp_options |= OPTION_MP_JOIN | OPTION_TYPE_SYN;
+               *remaining -= MPTCP_SUB_LEN_JOIN_SYN_ALIGN;
+               opts->mp_join_syns.token = mpcb->mptcp_rem_token;
+               opts->addr_id = tp->mptcp->loc_id;
+               opts->mp_join_syns.sender_nonce = tp->mptcp->mptcp_loc_nonce;
+       }
+}
+
+void mptcp_synack_options(struct request_sock *req,
+                         struct tcp_out_options *opts, unsigned *remaining)
+{
+       struct mptcp_request_sock *mtreq;
+       mtreq = mptcp_rsk(req);
+
+       opts->options |= OPTION_MPTCP;
+       /* MPCB not yet set - thus it's a new MPTCP-session */
+       if (!mtreq->mpcb) {
+               opts->mptcp_options |= OPTION_MP_CAPABLE | OPTION_TYPE_SYNACK;
+               opts->mp_capable.sender_key = mtreq->mptcp_loc_key;
+               opts->dss_csum = !!sysctl_mptcp_checksum || mtreq->dss_csum;
+               *remaining -= MPTCP_SUB_LEN_CAPABLE_SYN_ALIGN;
+       } else {
+               opts->mptcp_options |= OPTION_MP_JOIN | OPTION_TYPE_SYNACK;
+               opts->mp_join_syns.sender_truncated_mac =
+                               mtreq->mptcp_hash_tmac;
+               opts->mp_join_syns.sender_nonce = mtreq->mptcp_loc_nonce;
+               opts->addr_id = mtreq->loc_id;
+               *remaining -= MPTCP_SUB_LEN_JOIN_SYNACK_ALIGN;
+       }
+}
+
+void mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+                              struct tcp_out_options *opts, unsigned *size)
+{
+       struct tcp_sock *tp = tcp_sk(sk), *meta_tp = mptcp_meta_tp(tp);
+       struct mptcp_cb *mpcb = tp->mpcb;
+       struct tcp_skb_cb *tcb = skb ? TCP_SKB_CB(skb) : NULL;
+
+       /* In fallback mp_fail-mode, we have to repeat it until the fallback
+        * has been done by the sender
+        */
+       if (unlikely(tp->mptcp->send_mp_fail)) {
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_MP_FAIL;
+               opts->data_ack = (__u32)(mpcb->csum_cutoff_seq >> 32);
+               opts->data_seq = (__u32)mpcb->csum_cutoff_seq;
+               *size += MPTCP_SUB_LEN_FAIL;
+               return;
+       }
+
+       if (unlikely(tp->send_mp_fclose)) {
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_MP_FCLOSE;
+               opts->mp_capable.receiver_key = mpcb->mptcp_rem_key;
+               *size += MPTCP_SUB_LEN_FCLOSE_ALIGN;
+               return;
+       }
+
+       /* 1. If we are the sender of the infinite-mapping, we need the
+        *    MPTCPHDR_INF-flag, because a retransmission of the
+        *    infinite-announcment still needs the mptcp-option.
+        *
+        *    We need infinite_cutoff_seq, because retransmissions from before
+        *    the infinite-cutoff-moment still need the MPTCP-signalling to stay
+        *    consistent.
+        *
+        * 2. If we are the receiver of the infinite-mapping, we always skip
+        *    mptcp-options, because acknowledgments from before the
+        *    infinite-mapping point have already been sent out.
+        *
+        * I know, the whole infinite-mapping stuff is ugly...
+        *
+        * TODO: Handle wrapped data-sequence numbers
+        *       (even if it's very unlikely)
+        */
+       if (unlikely(mpcb->infinite_mapping_snd) &&
+           tp->mptcp->fully_established &&
+           ((mpcb->send_infinite_mapping && tcb &&
+             !(tcb->mptcp_flags & MPTCPHDR_INF) &&
+             !before(tcb->seq, tp->mptcp->infinite_cutoff_seq)) ||
+            !mpcb->send_infinite_mapping))
+               return;
+
+       if (unlikely(tp->mptcp->include_mpc)) {
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_MP_CAPABLE |
+                                      OPTION_TYPE_ACK;
+               *size += MPTCP_SUB_LEN_CAPABLE_ACK_ALIGN;
+               opts->mp_capable.sender_key = mpcb->mptcp_loc_key;
+               opts->mp_capable.receiver_key = mpcb->mptcp_rem_key;
+               opts->dss_csum = mpcb->dss_csum;
+
+               if (skb)
+                       tp->mptcp->include_mpc = 0;
+       }
+       if (unlikely(tp->mptcp->pre_established)) {
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_MP_JOIN | OPTION_TYPE_ACK;
+               *size += MPTCP_SUB_LEN_JOIN_ACK_ALIGN;
+       }
+
+       if (!tp->mptcp->include_mpc && !tp->mptcp->pre_established) {
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_DATA_ACK;
+               /* If !skb, we come from tcp_current_mss and thus we always
+                * assume that the DSS-option will be set for the data-packet.
+                */
+               if (skb && !mptcp_is_data_seq(skb)) {
+                       opts->data_ack = meta_tp->rcv_nxt;
+
+                       *size += MPTCP_SUB_LEN_ACK_ALIGN;
+               } else {
+                       opts->data_ack = meta_tp->rcv_nxt;
+
+                       /* Doesn't matter, if csum included or not. It will be
+                        * either 10 or 12, and thus aligned = 12
+                        */
+                       *size += MPTCP_SUB_LEN_ACK_ALIGN +
+                                MPTCP_SUB_LEN_SEQ_ALIGN;
+               }
+
+               *size += MPTCP_SUB_LEN_DSS_ALIGN;
+       }
+
+       if (mpcb->pm_ops->addr_signal)
+               mpcb->pm_ops->addr_signal(sk, size, opts, skb);
+
+       if (unlikely(tp->mptcp->send_mp_prio) &&
+           MAX_TCP_OPTION_SPACE - *size >= MPTCP_SUB_LEN_PRIO_ALIGN) {
+               opts->options |= OPTION_MPTCP;
+               opts->mptcp_options |= OPTION_MP_PRIO;
+               if (skb)
+                       tp->mptcp->send_mp_prio = 0;
+               *size += MPTCP_SUB_LEN_PRIO_ALIGN;
+       }
+
+       return;
+}
+
+u16 mptcp_select_window(struct sock *sk)
+{
+       u16 new_win             = tcp_select_window(sk);
+       struct tcp_sock *tp     = tcp_sk(sk);
+       struct tcp_sock *meta_tp = mptcp_meta_tp(tp);
+
+       meta_tp->rcv_wnd        = tp->rcv_wnd;
+       meta_tp->rcv_wup        = meta_tp->rcv_nxt;
+
+       return new_win;
+}
+
+void mptcp_options_write(__be32 *ptr, struct tcp_sock *tp,
+                        struct tcp_out_options *opts,
+                        struct sk_buff *skb)
+{
+       if (unlikely(OPTION_MP_CAPABLE & opts->mptcp_options)) {
+               struct mp_capable *mpc = (struct mp_capable *)ptr;
+
+               mpc->kind = TCPOPT_MPTCP;
+
+               if ((OPTION_TYPE_SYN & opts->mptcp_options) ||
+                   (OPTION_TYPE_SYNACK & opts->mptcp_options)) {
+                       mpc->sender_key = opts->mp_capable.sender_key;
+                       mpc->len = MPTCP_SUB_LEN_CAPABLE_SYN;
+                       ptr += MPTCP_SUB_LEN_CAPABLE_SYN_ALIGN >> 2;
+               } else if (OPTION_TYPE_ACK & opts->mptcp_options) {
+                       mpc->sender_key = opts->mp_capable.sender_key;
+                       mpc->receiver_key = opts->mp_capable.receiver_key;
+                       mpc->len = MPTCP_SUB_LEN_CAPABLE_ACK;
+                       ptr += MPTCP_SUB_LEN_CAPABLE_ACK_ALIGN >> 2;
+               }
+
+               mpc->sub = MPTCP_SUB_CAPABLE;
+               mpc->ver = 0;
+               mpc->a = opts->dss_csum;
+               mpc->b = 0;
+               mpc->rsv = 0;
+               mpc->h = 1;
+       }
+
+       if (unlikely(OPTION_MP_JOIN & opts->mptcp_options)) {
+               struct mp_join *mpj = (struct mp_join *)ptr;
+
+               mpj->kind = TCPOPT_MPTCP;
+               mpj->sub = MPTCP_SUB_JOIN;
+               mpj->rsv = 0;
+               mpj->addr_id = opts->addr_id;
+
+               if (OPTION_TYPE_SYN & opts->mptcp_options) {
+                       mpj->len = MPTCP_SUB_LEN_JOIN_SYN;
+                       mpj->u.syn.token = opts->mp_join_syns.token;
+                       mpj->u.syn.nonce = opts->mp_join_syns.sender_nonce;
+                       mpj->b = tp->mptcp->low_prio;
+                       ptr += MPTCP_SUB_LEN_JOIN_SYN_ALIGN >> 2;
+               } else if (OPTION_TYPE_SYNACK & opts->mptcp_options) {
+                       mpj->len = MPTCP_SUB_LEN_JOIN_SYNACK;
+                       mpj->u.synack.mac =
+                               opts->mp_join_syns.sender_truncated_mac;
+                       mpj->u.synack.nonce = opts->mp_join_syns.sender_nonce;
+                       mpj->b = tp->mptcp->low_prio;
+                       ptr += MPTCP_SUB_LEN_JOIN_SYNACK_ALIGN >> 2;
+               } else if (OPTION_TYPE_ACK & opts->mptcp_options) {
+                       mpj->len = MPTCP_SUB_LEN_JOIN_ACK;
+                       memcpy(mpj->u.ack.mac, &tp->mptcp->sender_mac[0], 20);
+                       ptr += MPTCP_SUB_LEN_JOIN_ACK_ALIGN >> 2;
+               }
+       }
+       if (unlikely(OPTION_ADD_ADDR & opts->mptcp_options)) {
+               struct mp_add_addr *mpadd = (struct mp_add_addr *)ptr;
+
+               mpadd->kind = TCPOPT_MPTCP;
+               if (opts->add_addr_v4) {
+                       mpadd->len = MPTCP_SUB_LEN_ADD_ADDR4;
+                       mpadd->sub = MPTCP_SUB_ADD_ADDR;
+                       mpadd->ipver = 4;
+                       mpadd->addr_id = opts->add_addr4.addr_id;
+                       mpadd->u.v4.addr = opts->add_addr4.addr;
+                       ptr += MPTCP_SUB_LEN_ADD_ADDR4_ALIGN >> 2;
+               } else if (opts->add_addr_v6) {
+                       mpadd->len = MPTCP_SUB_LEN_ADD_ADDR6;
+                       mpadd->sub = MPTCP_SUB_ADD_ADDR;
+                       mpadd->ipver = 6;
+                       mpadd->addr_id = opts->add_addr6.addr_id;
+                       memcpy(&mpadd->u.v6.addr, &opts->add_addr6.addr,
+                              sizeof(mpadd->u.v6.addr));
+                       ptr += MPTCP_SUB_LEN_ADD_ADDR6_ALIGN >> 2;
+               }
+       }
+       if (unlikely(OPTION_REMOVE_ADDR & opts->mptcp_options)) {
+               struct mp_remove_addr *mprem = (struct mp_remove_addr *)ptr;
+               u8 *addrs_id;
+               int id, len, len_align;
+
+               len = mptcp_sub_len_remove_addr(opts->remove_addrs);
+               len_align = mptcp_sub_len_remove_addr_align(opts->remove_addrs);
+
+               mprem->kind = TCPOPT_MPTCP;
+               mprem->len = len;
+               mprem->sub = MPTCP_SUB_REMOVE_ADDR;
+               mprem->rsv = 0;
+               addrs_id = &mprem->addrs_id;
+
+               mptcp_for_each_bit_set(opts->remove_addrs, id)
+                       *(addrs_id++) = id;
+
+               /* Fill the rest with NOP's */
+               if (len_align > len) {
+                       int i;
+                       for (i = 0; i < len_align - len; i++)
+                               *(addrs_id++) = TCPOPT_NOP;
+               }
+
+               ptr += len_align >> 2;
+       }
+       if (unlikely(OPTION_MP_FAIL & opts->mptcp_options)) {
+               struct mp_fail *mpfail = (struct mp_fail *)ptr;
+
+               mpfail->kind = TCPOPT_MPTCP;
+               mpfail->len = MPTCP_SUB_LEN_FAIL;
+               mpfail->sub = MPTCP_SUB_FAIL;
+               mpfail->rsv1 = 0;
+               mpfail->rsv2 = 0;
+               mpfail->data_seq = htonll(((u64)opts->data_ack << 32) | opts->data_seq);
+
+               ptr += MPTCP_SUB_LEN_FAIL_ALIGN >> 2;
+       }
+       if (unlikely(OPTION_MP_FCLOSE & opts->mptcp_options)) {
+               struct mp_fclose *mpfclose = (struct mp_fclose *)ptr;
+
+               mpfclose->kind = TCPOPT_MPTCP;
+               mpfclose->len = MPTCP_SUB_LEN_FCLOSE;
+               mpfclose->sub = MPTCP_SUB_FCLOSE;
+               mpfclose->rsv1 = 0;
+               mpfclose->rsv2 = 0;
+               mpfclose->key = opts->mp_capable.receiver_key;
+
+               ptr += MPTCP_SUB_LEN_FCLOSE_ALIGN >> 2;
+       }
+
+       if (OPTION_DATA_ACK & opts->mptcp_options) {
+               if (!mptcp_is_data_seq(skb)) {
+                       struct mp_dss *mdss = (struct mp_dss *)ptr;
+
+                       mdss->kind = TCPOPT_MPTCP;
+                       mdss->sub = MPTCP_SUB_DSS;
+                       mdss->rsv1 = 0;
+                       mdss->rsv2 = 0;
+                       mdss->F = 0;
+                       mdss->m = 0;
+                       mdss->M = 0;
+                       mdss->a = 0;
+                       mdss->A = 1;
+                       mdss->len = mptcp_sub_len_dss(mdss, tp->mpcb->dss_csum);
+
+                       ptr++;
+                       *ptr++ = htonl(opts->data_ack);
+               } else {
+                       /**** Just update the data_ack ****/
+
+                       /* Get pointer to data_ack-field. MPTCP is always at
+                        * the end of the TCP-options.
+                        */
+                       /* TODO if we allow sending 64-bit dseq's we have to change "16" */
+                       __be32 *dack = (__be32 *)(skb->data + (tcp_hdr(skb)->doff << 2) - 16);
+
+                       *dack = htonl(opts->data_ack);
+               }
+       }
+       if (unlikely(OPTION_MP_PRIO & opts->mptcp_options)) {
+               struct mp_prio *mpprio = (struct mp_prio *)ptr;
+
+               mpprio->kind = TCPOPT_MPTCP;
+               mpprio->len = MPTCP_SUB_LEN_PRIO;
+               mpprio->sub = MPTCP_SUB_PRIO;
+               mpprio->rsv = 0;
+               mpprio->b = tp->mptcp->low_prio;
+               mpprio->addr_id = TCPOPT_NOP;
+
+               ptr += MPTCP_SUB_LEN_PRIO_ALIGN >> 2;
+       }
+}
+
+/* Returns the next segment to be sent from the mptcp meta-queue.
+ * (chooses the reinject queue if any segment is waiting in it, otherwise,
+ * chooses the normal write queue).
+ * Sets *@reinject to 1 if the returned segment comes from the
+ * reinject queue. Sets it to 0 if it is the regular send-head of the meta-sk,
+ * and sets it to -1 if it is a meta-level retransmission to optimize the
+ * receive-buffer.
+ */
+struct sk_buff *mptcp_next_segment(struct sock *meta_sk, int *reinject)
+{
+       struct mptcp_cb *mpcb = tcp_sk(meta_sk)->mpcb;
+       struct sk_buff *skb = NULL;
+       if (reinject)
+               *reinject = 0;
+
+       /* If we are in fallback-mode, just take from the meta-send-queue */
+       if (mpcb->infinite_mapping_snd || mpcb->send_infinite_mapping)
+               return tcp_send_head(meta_sk);
+
+       skb = skb_peek(&mpcb->reinject_queue);
+
+       if (skb) {
+               if (reinject)
+                       *reinject = 1;
+       } else {
+               skb = tcp_send_head(meta_sk);
+
+               if (!skb && meta_sk->sk_socket &&
+                   test_bit(SOCK_NOSPACE, &meta_sk->sk_socket->flags) &&
+                   sk_stream_wspace(meta_sk) < sk_stream_min_wspace(meta_sk)) {
+                       struct sock *subsk = get_available_subflow(meta_sk, NULL, NULL);
+                       if (!subsk)
+                               return NULL;
+
+                       skb = mptcp_rcv_buf_optimization(subsk, 0);
+                       if (skb && reinject)
+                               *reinject = -1;
+               }
+       }
+       return skb;
+}
+
+/* Sends the datafin */
+void mptcp_send_fin(struct sock *meta_sk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sk_buff *skb = tcp_write_queue_tail(meta_sk);
+       int mss_now;
+
+       if ((1 << meta_sk->sk_state) & (TCPF_CLOSE_WAIT | TCPF_LAST_ACK))
+               meta_tp->mpcb->passive_close = 1;
+
+       /* Optimization, tack on the FIN if we have a queue of
+        * unsent frames.  But be careful about outgoing SACKS
+        * and IP options.
+        */
+       mss_now = mptcp_current_mss(meta_sk);
+
+       if (tcp_send_head(meta_sk) != NULL) {
+               TCP_SKB_CB(skb)->mptcp_flags |= MPTCPHDR_FIN;
+               TCP_SKB_CB(skb)->end_seq++;
+               meta_tp->write_seq++;
+       } else {
+               /* Socket is locked, keep trying until memory is available. */
+               for (;;) {
+                       skb = alloc_skb_fclone(MAX_TCP_HEADER,
+                                              meta_sk->sk_allocation);
+                       if (skb)
+                               break;
+                       yield();
+               }
+               /* Reserve space for headers and prepare control bits. */
+               skb_reserve(skb, MAX_TCP_HEADER);
+
+               tcp_init_nondata_skb(skb, meta_tp->write_seq, TCPHDR_ACK);
+               TCP_SKB_CB(skb)->end_seq++;
+               TCP_SKB_CB(skb)->mptcp_flags |= MPTCPHDR_FIN | MPTCPHDR_SEQ;
+               tcp_queue_skb(meta_sk, skb);
+       }
+       __tcp_push_pending_frames(meta_sk, mss_now, TCP_NAGLE_OFF);
+}
+
+void mptcp_send_active_reset(struct sock *meta_sk, gfp_t priority)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       struct sock *sk = NULL, *sk_it = NULL, *tmpsk;
+
+       if (!mpcb->cnt_subflows)
+               return;
+
+       WARN_ON(meta_tp->send_mp_fclose);
+
+       /* First - select a socket */
+       sk = mptcp_select_ack_sock(meta_sk, 0);
+
+       /* May happen if no subflow is in an appropriate state */
+       if (!sk)
+               return;
+
+       /* We are in infinite mode - just send a reset */
+       if (mpcb->infinite_mapping_snd || mpcb->infinite_mapping_rcv) {
+               sk->sk_err = ECONNRESET;
+               if (tcp_need_reset(sk->sk_state))
+                       tcp_send_active_reset(sk, priority);
+               mptcp_sub_force_close(sk);
+               return;
+       }
+
+
+       tcp_sk(sk)->send_mp_fclose = 1;
+       /** Reset all other subflows */
+
+       /* tcp_done must be handled with bh disabled */
+       if (!in_serving_softirq())
+               local_bh_disable();
+
+       mptcp_for_each_sk_safe(mpcb, sk_it, tmpsk) {
+               if (tcp_sk(sk_it)->send_mp_fclose)
+                       continue;
+
+               sk_it->sk_err = ECONNRESET;
+               if (tcp_need_reset(sk_it->sk_state))
+                       tcp_send_active_reset(sk_it, GFP_ATOMIC);
+               mptcp_sub_force_close(sk_it);
+       }
+
+       if (!in_serving_softirq())
+               local_bh_enable();
+
+       tcp_send_ack(sk);
+       inet_csk_reset_keepalive_timer(sk, inet_csk(sk)->icsk_rto);
+
+       meta_tp->send_mp_fclose = 1;
+}
+
+static void mptcp_ack_retransmit_timer(struct sock *sk)
+{
+       struct sk_buff *skb;
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct inet_connection_sock *icsk = inet_csk(sk);
+
+       if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk))
+               goto out; /* Routing failure or similar */
+
+       if (!tp->retrans_stamp)
+               tp->retrans_stamp = tcp_time_stamp ? : 1;
+
+       if (tcp_write_timeout(sk)) {
+               tp->mptcp->pre_established = 0;
+               sk_stop_timer(sk, &tp->mptcp->mptcp_ack_timer);
+               tcp_send_active_reset(sk, GFP_ATOMIC);
+               goto out;
+       }
+
+       skb = alloc_skb(MAX_TCP_HEADER, GFP_ATOMIC);
+       if (skb == NULL) {
+               sk_reset_timer(sk, &tp->mptcp->mptcp_ack_timer,
+                              jiffies + icsk->icsk_rto);
+               return;
+       }
+
+       /* Reserve space for headers and prepare control bits */
+       skb_reserve(skb, MAX_TCP_HEADER);
+       tcp_init_nondata_skb(skb, tp->snd_una, TCPHDR_ACK);
+
+       TCP_SKB_CB(skb)->when = tcp_time_stamp;
+       if (tcp_transmit_skb(sk, skb, 0, GFP_ATOMIC) > 0) {
+               /* Retransmission failed because of local congestion,
+                * do not backoff.
+                */
+               if (!icsk->icsk_retransmits)
+                       icsk->icsk_retransmits = 1;
+               sk_reset_timer(sk, &tp->mptcp->mptcp_ack_timer,
+                              jiffies + icsk->icsk_rto);
+               return;
+       }
+
+
+       icsk->icsk_retransmits++;
+       icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX);
+       sk_reset_timer(sk, &tp->mptcp->mptcp_ack_timer,
+                      jiffies + icsk->icsk_rto);
+       if (retransmits_timed_out(sk, sysctl_tcp_retries1 + 1, 0, 0)) {
+               __sk_dst_reset(sk);
+       }
+
+out:;
+}
+
+void mptcp_ack_handler(unsigned long data)
+{
+       struct sock *sk = (struct sock *)data;
+       struct sock *meta_sk = mptcp_meta_sk(sk);
+
+       bh_lock_sock(meta_sk);
+       if (sock_owned_by_user(meta_sk)) {
+               /* Try again later */
+               sk_reset_timer(sk, &tcp_sk(sk)->mptcp->mptcp_ack_timer,
+                              jiffies + (HZ / 20));
+               goto out_unlock;
+       }
+
+       if (sk->sk_state == TCP_CLOSE)
+               goto out_unlock;
+
+       mptcp_ack_retransmit_timer(sk);
+
+       sk_mem_reclaim(sk);
+
+out_unlock:
+       bh_unlock_sock(meta_sk);
+       sock_put(sk);
+}
+
+/* Similar to tcp_retransmit_skb
+ *
+ * The diff is that we handle the retransmission-stats (retrans_stamp) at the
+ * meta-level.
+ */
+int mptcp_retransmit_skb(struct sock *meta_sk, struct sk_buff *skb)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct sock *subsk;
+       struct sk_buff *subskb;
+       unsigned int limit, tso_segs, mss_now;
+       int err = -1, oldpcount;
+
+       /* Do not sent more than we queued. 1/4 is reserved for possible
+        * copying overhead: fragmentation, tunneling, mangling etc.
+        *
+        * This is a meta-retransmission thus we check on the meta-socket.
+        */
+       if (atomic_read(&meta_sk->sk_wmem_alloc) >
+           min(meta_sk->sk_wmem_queued + (meta_sk->sk_wmem_queued >> 2), meta_sk->sk_sndbuf)) {
+               return -EAGAIN;
+       }
+
+       /* We need to make sure that the retransmitted segment can be sent on a
+        * subflow right now. If it is too big, it needs to be fragmented.
+        */
+       subsk = get_available_subflow(meta_sk, skb, &mss_now);
+       if (!subsk) {
+               /* We want to increase icsk_retransmits, thus return 0, so that
+                * mptcp_retransmit_timer enters the desired branch.
+                */
+               err = 0;
+               goto failed;
+       }
+
+       /* If the segment was cloned (e.g. a meta retransmission), the header
+        * must be expanded/copied so that there is no corruption of TSO
+        * information.
+        */
+       if (skb_unclone(skb, GFP_ATOMIC)) {
+               err = ENOMEM;
+               goto failed;
+       }
+
+       oldpcount = tcp_skb_pcount(skb);
+       tcp_set_skb_tso_segs(meta_sk, skb, mss_now);
+       tso_segs = tcp_skb_pcount(skb);
+       BUG_ON(!tso_segs);
+
+       /* The MSS might have changed and so the number of segments. We
+        * need to account for this change.
+        */
+       if (unlikely(oldpcount != tso_segs))
+               tcp_adjust_pcount(meta_sk, skb, oldpcount - tso_segs);
+
+       limit = mss_now;
+       if (tso_segs > 1 && !tcp_urg_mode(meta_tp))
+               limit = tcp_mss_split_point(subsk, skb, mss_now,
+                                           min_t(unsigned int,
+                                                 tcp_cwnd_test(tcp_sk(subsk), skb),
+                                                 subsk->sk_gso_max_segs),
+                                                 TCP_NAGLE_OFF);
+
+       if (skb->len > limit &&
+           unlikely(mptso_fragment(meta_sk, skb, limit, mss_now,
+                                   GFP_ATOMIC, 0)))
+               goto failed;
+
+       subskb = mptcp_skb_entail(subsk, skb, -1);
+       if (!subskb)
+               goto failed;
+
+       TCP_SKB_CB(skb)->when = tcp_time_stamp;
+       TCP_SKB_CB(subskb)->when = tcp_time_stamp;
+       err = tcp_transmit_skb(subsk, subskb, 1, GFP_ATOMIC);
+       if (!err) {
+               /* Update global TCP statistics. */
+               TCP_INC_STATS(sock_net(meta_sk), TCP_MIB_RETRANSSEGS);
+
+               /* Diff to tcp_retransmit_skb */
+
+               /* Save stamp of the first retransmit. */
+               if (!meta_tp->retrans_stamp)
+                       meta_tp->retrans_stamp = TCP_SKB_CB(subskb)->when;
+               mptcp_sub_event_new_data_sent(subsk, subskb, skb);
+       } else {
+               mptcp_transmit_skb_failed(subsk, skb, subskb);
+       }
+
+failed:
+       return err;
+}
+
+/* Similar to tcp_retransmit_timer
+ *
+ * The diff is that we have to handle retransmissions of the FAST_CLOSE-message
+ * and that we don't have an srtt estimation at the meta-level.
+ */
+void mptcp_retransmit_timer(struct sock *meta_sk)
+{
+       struct tcp_sock *meta_tp = tcp_sk(meta_sk);
+       struct mptcp_cb *mpcb = meta_tp->mpcb;
+       struct inet_connection_sock *meta_icsk = inet_csk(meta_sk);
+       int err;
+
+       /* In fallback, retransmission is handled at the subflow-level */
+       if (!meta_tp->packets_out || mpcb->infinite_mapping_snd ||
+           mpcb->send_infinite_mapping)
+               return;
+
+       WARN_ON(tcp_write_queue_empty(meta_sk));
+
+       if (!meta_tp->snd_wnd && !sock_flag(meta_sk, SOCK_DEAD) &&
+           !((1 << meta_sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) {
+               /* Receiver dastardly shrinks window. Our retransmits
+                * become zero probes, but we should not timeout this
+                * connection. If the socket is an orphan, time it out,
+                * we cannot allow such beasts to hang infinitely.
+                */
+               struct inet_sock *meta_inet = inet_sk(meta_sk);
+               if (meta_sk->sk_family == AF_INET) {
+                       LIMIT_NETDEBUG(KERN_DEBUG "MPTCP: Peer %pI4:%u/%u unexpectedly shrunk window %u:%u (repaired)\n",
+                                      &meta_inet->inet_daddr,
+                                      ntohs(meta_inet->inet_dport),
+                                      meta_inet->inet_num, meta_tp->snd_una,
+                                      meta_tp->snd_nxt);
+               }
+#if IS_ENABLED(CONFIG_IPV6)
+               else if (meta_sk->sk_family == AF_INET6) {
+                       LIMIT_NETDEBUG(KERN_DEBUG "MPTCP: Peer %pI6:%u/%u unexpectedly shrunk window %u:%u (repaired)\n",
+                                      &meta_sk->sk_v6_daddr,
+                                      ntohs(meta_inet->inet_dport),
+                                      meta_inet->inet_num, meta_tp->snd_una,
+                                      meta_tp->snd_nxt);
+               }
+#endif
+               if (tcp_time_stamp - meta_tp->rcv_tstamp > TCP_RTO_MAX) {
+                       tcp_write_err(meta_sk);
+                       return;
+               }
+
+               mptcp_retransmit_skb(meta_sk, tcp_write_queue_head(meta_sk));
+               goto out_reset_timer;
+       }
+
+       if (tcp_write_timeout(meta_sk))
+               return;
+
+       if (meta_icsk->icsk_retransmits == 0)
+               NET_INC_STATS_BH(sock_net(meta_sk), LINUX_MIB_TCPTIMEOUTS);
+
+       meta_icsk->icsk_ca_state = TCP_CA_Loss;
+
+       err = mptcp_retransmit_skb(meta_sk, tcp_write_queue_head(meta_sk));
+       if (err > 0) {
+               /* Retransmission failed because of local congestion,
+                * do not backoff.
+                */
+               if (!meta_icsk->icsk_retransmits)
+                       meta_icsk->icsk_retransmits = 1;
+               inet_csk_reset_xmit_timer(meta_sk, ICSK_TIME_RETRANS,
+                                         min(meta_icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL),
+                                         TCP_RTO_MAX);
+               return;
+       }
+
+       /* Increase the timeout each time we retransmit.  Note that
+        * we do not increase the rtt estimate.  rto is initialized
+        * from rtt, but increases here.  Jacobson (SIGCOMM 88) suggests
+        * that doubling rto each time is the least we can get away with.
+        * In KA9Q, Karn uses this for the first few times, and then
+        * goes to quadratic.  netBSD doubles, but only goes up to *64,
+        * and clamps at 1 to 64 sec afterwards.  Note that 120 sec is
+        * defined in the protocol as the maximum possible RTT.  I guess
+        * we'll have to use something other than TCP to talk to the
+        * University of Mars.
+        *
+        * PAWS allows us longer timeouts and large windows, so once
+        * implemented ftp to mars will work nicely. We will have to fix
+        * the 120 second clamps though!
+        */
+       meta_icsk->icsk_backoff++;
+       meta_icsk->icsk_retransmits++;
+
+out_reset_timer:
+       /* If stream is thin, use linear timeouts. Since 'icsk_backoff' is
+        * used to reset timer, set to 0. Recalculate 'icsk_rto' as this
+        * might be increased if the stream oscillates between thin and thick,
+        * thus the old value might already be too high compared to the value
+        * set by 'tcp_set_rto' in tcp_input.c which resets the rto without
+        * backoff. Limit to TCP_THIN_LINEAR_RETRIES before initiating
+        * exponential backoff behaviour to avoid continue hammering
+        * linear-timeout retransmissions into a black hole
+        */
+       if (meta_sk->sk_state == TCP_ESTABLISHED &&
+           (meta_tp->thin_lto || sysctl_tcp_thin_linear_timeouts) &&
+           tcp_stream_is_thin(meta_tp) &&
+           meta_icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) {
+               meta_icsk->icsk_backoff = 0;
+               /* We cannot do the same as in tcp_write_timer because the
+                * srtt is not set here.
+                */
+               mptcp_set_rto(meta_sk);
+       } else {
+               /* Use normal (exponential) backoff */
+               meta_icsk->icsk_rto = min(meta_icsk->icsk_rto << 1, TCP_RTO_MAX);
+       }
+       inet_csk_reset_xmit_timer(meta_sk, ICSK_TIME_RETRANS, meta_icsk->icsk_rto, TCP_RTO_MAX);
+
+       return;
+}
+
+/* Modify values to an mptcp-level for the initial window of new subflows */
+void mptcp_select_initial_window(int __space, __u32 mss, __u32 *rcv_wnd,
+                               __u32 *window_clamp, int wscale_ok,
+                               __u8 *rcv_wscale, __u32 init_rcv_wnd,
+                                const struct sock *sk)
+{
+       struct mptcp_cb *mpcb = tcp_sk(sk)->mpcb;
+
+       *window_clamp = mpcb->orig_window_clamp;
+       __space = tcp_win_from_space(mpcb->orig_sk_rcvbuf);
+
+       tcp_select_initial_window(__space, mss, rcv_wnd, window_clamp,
+                                 wscale_ok, rcv_wscale, init_rcv_wnd, sk);
+}
+
+unsigned int mptcp_current_mss(struct sock *meta_sk)
+{
+       unsigned int mss = 0;
+       struct sock *sk;
+
+       mptcp_for_each_sk(tcp_sk(meta_sk)->mpcb, sk) {
+               int this_mss;
+
+               if (!mptcp_sk_can_send(sk))
+                       continue;
+
+               this_mss = tcp_current_mss(sk);
+               if (this_mss > mss)
+                       mss = this_mss;
+       }
+
+       /* If no subflow is available, we take a default-mss from the
+        * meta-socket.
+        */
+       return !mss ? tcp_current_mss(meta_sk) : mss;
+}
+
+int mptcp_select_size(const struct sock *meta_sk, bool sg)
+{
+       int mss = 0; /* We look for the smallest MSS */
+       struct sock *sk;
+
+       mptcp_for_each_sk(tcp_sk(meta_sk)->mpcb, sk) {
+               int this_mss;
+
+               if (!mptcp_sk_can_send(sk))
+                       continue;
+
+               this_mss = tcp_sk(sk)->mss_cache;
+               if (this_mss > mss)
+                       mss = this_mss;
+       }
+
+       if (sg) {
+               if (mptcp_sk_can_gso(meta_sk)) {
+                       mss = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
+               } else {
+                       int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);
+
+                       if (mss >= pgbreak &&
+                           mss <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
+                               mss = pgbreak;
+               }
+       }
+
+       return !mss ? tcp_sk(meta_sk)->mss_cache : mss;
+}
+
+int mptcp_check_snd_buf(const struct tcp_sock *tp)
+{
+       struct sock *sk;
+       u32 rtt_max = tp->srtt;
+       u64 bw_est;
+
+       if (!tp->srtt)
+               return tp->reordering + 1;
+
+       mptcp_for_each_sk(tp->mpcb, sk) {
+               if (!mptcp_sk_can_send(sk))
+                       continue;
+
+               if (rtt_max < tcp_sk(sk)->srtt)
+                       rtt_max = tcp_sk(sk)->srtt;
+       }
+
+       bw_est = div64_u64(((u64)tp->snd_cwnd * rtt_max) << 16,
+                               (u64)tp->srtt);
+
+       return max_t(unsigned int, (u32)(bw_est >> 16),
+                       tp->reordering + 1);
+
+}
+
+unsigned int mptcp_xmit_size_goal(struct sock *meta_sk, u32 mss_now,
+                                 int large_allowed)
+{
+       struct sock *sk;
+       u32 xmit_size_goal = 0;
+
+       if (large_allowed && mptcp_sk_can_gso(meta_sk)) {
+               mptcp_for_each_sk(tcp_sk(meta_sk)->mpcb, sk) {
+                       int this_size_goal;
+
+                       if (!mptcp_sk_can_send(sk))
+                               continue;
+
+                       this_size_goal = tcp_xmit_size_goal(sk, mss_now, 1);
+                       if (this_size_goal > xmit_size_goal)
+                               xmit_size_goal = this_size_goal;
+               }
+       }
+
+       return max(xmit_size_goal, mss_now);
+}
+
+/* Similar to tcp_trim_head - but we correctly copy the DSS-option */
+int mptcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
+{
+       int dsslen = MPTCP_SUB_LEN_DSS_ALIGN + MPTCP_SUB_LEN_ACK_ALIGN +
+                    MPTCP_SUB_LEN_SEQ_ALIGN;
+       char dss[dsslen];
+
+       /* DSS-option must be recovered afterwards. */
+       memcpy(dss, skb->data - dsslen, dsslen);
+
+       if (skb_cloned(skb)) {
+               /* pskb_expand_head will delete our DSS-option. We have to copy
+                * it back if pskb_expand_head succeeds.
+                */
+
+               if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+                       return -ENOMEM;
+
+               memcpy(skb->data - dsslen, dss, dsslen);
+       }
+
+       __pskb_trim_head(skb, len);
+
+       /* Put the DSS-option back in our header */
+       memcpy(skb->data - dsslen, dss, dsslen);
+
+       TCP_SKB_CB(skb)->seq += len;
+       skb->ip_summed = CHECKSUM_PARTIAL;
+
+       skb->truesize        -= len;
+       sk->sk_wmem_queued   -= len;
+       sk_mem_uncharge(sk, len);
+       sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
+
+       /* Any change of skb->len requires recalculation of tso factor. */
+       if (tcp_skb_pcount(skb) > 1)
+               tcp_set_skb_tso_segs(sk, skb, tcp_skb_mss(skb));
+
+       return 0;
+}
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_pm.c linux-3.14.45/net/mptcp/mptcp_pm.c
--- linux-3.14.45.orig/net/mptcp/mptcp_pm.c     1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_pm.c  2015-06-24 14:15:48.931862523 +0200
@@ -0,0 +1,170 @@
+/*
+ *     MPTCP implementation - MPTCP-subflow-management
+ *
+ *     Initial Design & Implementation:
+ *     Sébastien Barré <sebastien.barre@uclouvain.be>
+ *
+ *     Current Maintainer & Author:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     Additional authors:
+ *     Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ *     Gregory Detal <gregory.detal@uclouvain.be>
+ *     Fabien Duchêne <fabien.duchene@uclouvain.be>
+ *     Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ *     Lavkesh Lahngir <lavkesh51@gmail.com>
+ *     Andreas Ripke <ripke@neclab.eu>
+ *     Vlad Dogaru <vlad.dogaru@intel.com>
+ *     Octavian Purdila <octavian.purdila@intel.com>
+ *     John Ronan <jronan@tssg.org>
+ *     Catalin Nicutar <catalin.nicutar@gmail.com>
+ *     Brandon Heller <brandonh@stanford.edu>
+ *
+ *
+ *     This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+
+#include <linux/module.h>
+#include <net/mptcp.h>
+
+static DEFINE_SPINLOCK(mptcp_pm_list_lock);
+static LIST_HEAD(mptcp_pm_list);
+
+static int mptcp_default_index(sa_family_t family, union inet_addr *addr,
+                              struct net *net)
+{
+       return 0;
+}
+
+struct mptcp_pm_ops mptcp_pm_default = {
+       .get_local_index = mptcp_default_index,
+       .get_local_id = mptcp_default_index, /* We do not care */
+       .name = "default",
+       .owner = THIS_MODULE,
+};
+
+static struct mptcp_pm_ops *mptcp_pm_find(const char *name)
+{
+       struct mptcp_pm_ops *e;
+
+       list_for_each_entry_rcu(e, &mptcp_pm_list, list) {
+               if (strcmp(e->name, name) == 0)
+                       return e;
+       }
+
+       return NULL;
+}
+
+int mptcp_register_path_manager(struct mptcp_pm_ops *pm)
+{
+       int ret = 0;
+
+       if (!pm->get_local_index || !pm->get_local_id)
+               return -EINVAL;
+
+       spin_lock(&mptcp_pm_list_lock);
+       if (mptcp_pm_find(pm->name)) {
+               pr_notice("%s already registered\n", pm->name);
+               ret = -EEXIST;
+       } else {
+               list_add_tail_rcu(&pm->list, &mptcp_pm_list);
+               pr_info("%s registered\n", pm->name);
+       }
+       spin_unlock(&mptcp_pm_list_lock);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(mptcp_register_path_manager);
+
+void mptcp_unregister_path_manager(struct mptcp_pm_ops *pm)
+{
+       spin_lock(&mptcp_pm_list_lock);
+       list_del_rcu(&pm->list);
+       spin_unlock(&mptcp_pm_list_lock);
+}
+EXPORT_SYMBOL_GPL(mptcp_unregister_path_manager);
+
+void mptcp_get_default_path_manager(char *name)
+{
+       struct mptcp_pm_ops *pm;
+
+       BUG_ON(list_empty(&mptcp_pm_list));
+
+       rcu_read_lock();
+       pm = list_entry(mptcp_pm_list.next, struct mptcp_pm_ops, list);
+       strncpy(name, pm->name, MPTCP_PM_NAME_MAX);
+       rcu_read_unlock();
+}
+
+int mptcp_set_default_path_manager(const char *name)
+{
+       struct mptcp_pm_ops *pm;
+       int ret = -ENOENT;
+
+       spin_lock(&mptcp_pm_list_lock);
+       pm = mptcp_pm_find(name);
+#ifdef CONFIG_MODULES
+       if (!pm && capable(CAP_NET_ADMIN)) {
+               spin_unlock(&mptcp_pm_list_lock);
+
+               request_module("mptcp_%s", name);
+               spin_lock(&mptcp_pm_list_lock);
+               pm = mptcp_pm_find(name);
+       }
+#endif
+
+       if (pm) {
+               list_move(&pm->list, &mptcp_pm_list);
+               ret = 0;
+       } else {
+               pr_info("%s is not available\n", name);
+       }
+       spin_unlock(&mptcp_pm_list_lock);
+
+       return ret;
+}
+
+void mptcp_init_path_manager(struct mptcp_cb *mpcb)
+{
+       struct mptcp_pm_ops *pm;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(pm, &mptcp_pm_list, list) {
+               if (try_module_get(pm->owner)) {
+                       mpcb->pm_ops = pm;
+                       break;
+               }
+       }
+       rcu_read_unlock();
+}
+
+/* Manage refcounts on socket close. */
+void mptcp_cleanup_path_manager(struct mptcp_cb *mpcb)
+{
+       module_put(mpcb->pm_ops->owner);
+}
+
+/* Fallback to the default path-manager. */
+void mptcp_fallback_default(struct mptcp_cb *mpcb)
+{
+       struct mptcp_pm_ops *pm;
+
+       mptcp_cleanup_path_manager(mpcb);
+       pm = mptcp_pm_find("default");
+
+       /* Cannot fail - it's the default module */
+       try_module_get(pm->owner);
+       mpcb->pm_ops = pm;
+}
+EXPORT_SYMBOL_GPL(mptcp_fallback_default);
+
+/* Set default value from kernel configuration at bootup */
+static int __init mptcp_path_manager_default(void)
+{
+       return mptcp_set_default_path_manager(CONFIG_DEFAULT_MPTCP_PM);
+}
+late_initcall(mptcp_path_manager_default);
diff -Nur linux-3.14.45.orig/net/mptcp/mptcp_wvegas.c linux-3.14.45/net/mptcp/mptcp_wvegas.c
--- linux-3.14.45.orig/net/mptcp/mptcp_wvegas.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-3.14.45/net/mptcp/mptcp_wvegas.c      2015-06-24 14:15:48.931862523 +0200
@@ -0,0 +1,270 @@
+/*
+ *     MPTCP implementation - WEIGHTED VEGAS
+ *
+ *     Algorithm design:
+ *     Yu Cao <cyAnalyst@126.com>
+ *     Mingwei Xu <xmw@csnet1.cs.tsinghua.edu.cn>
+ *     Xiaoming Fu <fu@cs.uni-goettinggen.de>
+ *
+ *     Implementation:
+ *     Yu Cao <cyAnalyst@126.com>
+ *     Enhuan Dong <deh13@mails.tsinghua.edu.cn>
+ *
+ *     Ported to the official MPTCP-kernel:
+ *     Christoph Paasch <christoph.paasch@uclouvain.be>
+ *
+ *     This program is free software; you can redistribute it and/or
+ *     modify it under the terms of the GNU General Public License
+ *     as published by the Free Software Foundation; either version
+ *     2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/skbuff.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+#include <linux/module.h>
+#include <linux/tcp.h>
+
+static int initial_alpha = 2;
+static int total_alpha = 10;
+static int gamma = 1;
+
+module_param(initial_alpha, int, 0644);
+MODULE_PARM_DESC(initial_alpha, "initial alpha for all subflows");
+module_param(total_alpha, int, 0644);
+MODULE_PARM_DESC(total_alpha, "total alpha for all subflows");
+module_param(gamma, int, 0644);
+MODULE_PARM_DESC(gamma, "limit on increase (scale by 2)");
+
+#define MPTCP_WVEGAS_SCALE 16
+
+/* wVegas variables */
+struct wvegas {
+       u32     beg_snd_nxt;    /* right edge during last RTT */
+       u8      doing_wvegas_now;/* if true, do wvegas for this RTT */
+
+       u16     cnt_rtt;                /* # of RTTs measured within last RTT */
+       u32 sampled_rtt; /* cumulative RTTs measured within last RTT (in usec) */
+       u32     base_rtt;       /* the min of all wVegas RTT measurements seen (in usec) */
+
+       u64 instant_rate; /* cwnd / srtt_us, unit: pkts/us * 2^16 */
+       u64 weight; /* the ratio of subflow's rate to the total rate, * 2^16 */
+       int alpha; /* alpha for each subflows */
+
+       u32 queue_delay; /* queue delay*/
+};
+
+
+static inline u64 mptcp_wvegas_scale(u32 val, int scale)
+{
+       return (u64) val << scale;
+}
+
+static void wvegas_enable(struct sock *sk)
+{
+       const struct tcp_sock *tp = tcp_sk(sk);
+       struct wvegas *wvegas = inet_csk_ca(sk);
+
+       wvegas->doing_wvegas_now = 1;
+
+       wvegas->beg_snd_nxt = tp->snd_nxt;
+
+       wvegas->cnt_rtt = 0;
+       wvegas->sampled_rtt = 0;
+
+       wvegas->instant_rate = 0;
+       wvegas->alpha = initial_alpha;
+       wvegas->weight = mptcp_wvegas_scale(1, MPTCP_WVEGAS_SCALE);
+
+       wvegas->queue_delay = 0;
+}
+
+static inline void wvegas_disable(struct sock *sk)
+{
+       struct wvegas *wvegas = inet_csk_ca(sk);
+
+       wvegas->doing_wvegas_now = 0;
+}
+
+static void mptcp_wvegas_init(struct sock *sk)
+{
+       struct wvegas *wvegas = inet_csk_ca(sk);
+
+       wvegas->base_rtt = 0x7fffffff;
+       wvegas_enable(sk);
+}
+
+static inline u64 mptcp_wvegas_rate(u32 cwnd, u32 rtt_us)
+{
+       return div_u64(mptcp_wvegas_scale(cwnd, MPTCP_WVEGAS_SCALE), rtt_us);
+}
+
+static void mptcp_wvegas_pkts_acked(struct sock *sk, u32 cnt, s32 rtt_us)
+{
+       struct wvegas *wvegas = inet_csk_ca(sk);
+       u32 vrtt;
+
+       if (rtt_us < 0)
+               return;
+
+       vrtt = rtt_us + 1;
+
+       if (vrtt < wvegas->base_rtt)
+               wvegas->base_rtt = vrtt;
+
+       wvegas->sampled_rtt += vrtt;
+       wvegas->cnt_rtt++;
+}
+
+static void mptcp_wvegas_state(struct sock *sk, u8 ca_state)
+{
+       if (ca_state == TCP_CA_Open)
+               wvegas_enable(sk);
+       else
+               wvegas_disable(sk);
+}
+
+static void mptcp_wvegas_cwnd_event(struct sock *sk, enum tcp_ca_event event)
+{
+       if (event == CA_EVENT_CWND_RESTART) {
+               mptcp_wvegas_init(sk);
+       } else if (event == CA_EVENT_LOSS) {
+               struct wvegas *wvegas = inet_csk_ca(sk);
+               wvegas->instant_rate = 0;
+       }
+}
+
+static inline u32 mptcp_wvegas_ssthresh(struct tcp_sock *tp)
+{
+       return  min(tp->snd_ssthresh, tp->snd_cwnd - 1);
+}
+
+static u64 mptcp_wvegas_weight(struct mptcp_cb *mpcb, struct sock *sk)
+{
+       u64 total_rate = 0;
+       struct sock *sub_sk;
+       struct wvegas *wvegas = inet_csk_ca(sk);
+
+       if (!mpcb)
+               return wvegas->weight;
+
+
+       mptcp_for_each_sk(mpcb, sub_sk) {
+               struct wvegas *sub_wvegas = inet_csk_ca(sub_sk);
+
+               /* sampled_rtt is initialized by 0 */
+               if (mptcp_sk_can_send(sub_sk) && (sub_wvegas->sampled_rtt > 0))
+                       total_rate += sub_wvegas->instant_rate;
+       }
+
+       if (total_rate && wvegas->instant_rate)
+               return div64_u64(mptcp_wvegas_scale(wvegas->instant_rate, MPTCP_WVEGAS_SCALE), total_rate);
+       else
+               return wvegas->weight;
+}
+
+static void mptcp_wvegas_cong_avoid(struct sock *sk, u32 ack, u32 acked, u32 in_flight)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       struct wvegas *wvegas = inet_csk_ca(sk);
+
+       if (!wvegas->doing_wvegas_now) {
+               tcp_reno_cong_avoid(sk, ack, acked, in_flight);
+               return;
+       }
+
+       if (after(ack, wvegas->beg_snd_nxt)) {
+               wvegas->beg_snd_nxt  = tp->snd_nxt;
+
+               if (wvegas->cnt_rtt <= 2) {
+                       tcp_reno_cong_avoid(sk, ack, acked, in_flight);
+               } else {
+                       u32 rtt, diff, q_delay;
+                       u64 target_cwnd;
+
+                       rtt = wvegas->sampled_rtt / wvegas->cnt_rtt;
+                       target_cwnd = div_u64(((u64)tp->snd_cwnd * wvegas->base_rtt), rtt);
+
+                       diff = div_u64((u64)tp->snd_cwnd * (rtt - wvegas->base_rtt), rtt);
+
+                       if (diff > gamma && tp->snd_cwnd <= tp->snd_ssthresh) {
+                               tp->snd_cwnd = min(tp->snd_cwnd, (u32)target_cwnd+1);
+                               tp->snd_ssthresh = mptcp_wvegas_ssthresh(tp);
+
+                       } else if (tp->snd_cwnd <= tp->snd_ssthresh) {
+                               tcp_slow_start(tp, acked);
+                       } else {
+                               if (diff >= wvegas->alpha) {
+                                       wvegas->instant_rate = mptcp_wvegas_rate(tp->snd_cwnd, rtt);
+                                       wvegas->weight = mptcp_wvegas_weight(tp->mpcb, sk);
+                                       wvegas->alpha = max(2U, (u32)((wvegas->weight * total_alpha) >> MPTCP_WVEGAS_SCALE));
+                               }
+                               if (diff > wvegas->alpha) {
+                                       tp->snd_cwnd--;
+                                       tp->snd_ssthresh = mptcp_wvegas_ssthresh(tp);
+                               } else if (diff < wvegas->alpha) {
+                                       tp->snd_cwnd++;
+                               }
+
+                               /* Try to drain link queue if needed*/
+                               q_delay = rtt - wvegas->base_rtt;
+                               if ((wvegas->queue_delay == 0) || (wvegas->queue_delay > q_delay))
+                                       wvegas->queue_delay = q_delay;
+
+                               if (q_delay >= 2 * wvegas->queue_delay) {
+                                       u32 backoff_factor = div_u64(mptcp_wvegas_scale(wvegas->base_rtt, MPTCP_WVEGAS_SCALE), 2 * rtt);
+                                       tp->snd_cwnd = ((u64)tp->snd_cwnd * backoff_factor) >> MPTCP_WVEGAS_SCALE;
+                                       wvegas->queue_delay = 0;
+                               }
+                       }
+
+                       if (tp->snd_cwnd < 2)
+                               tp->snd_cwnd = 2;
+                       else if (tp->snd_cwnd > tp->snd_cwnd_clamp)
+                               tp->snd_cwnd = tp->snd_cwnd_clamp;
+
+                       tp->snd_ssthresh = tcp_current_ssthresh(sk);
+               }
+
+               wvegas->cnt_rtt = 0;
+               wvegas->sampled_rtt = 0;
+       }
+       /* Use normal slow start */
+       else if (tp->snd_cwnd <= tp->snd_ssthresh)
+               tcp_slow_start(tp, acked);
+}
+
+
+static struct tcp_congestion_ops mptcp_wvegas __read_mostly = {
+       .flags          = TCP_CONG_RTT_STAMP,
+       .init           = mptcp_wvegas_init,
+       .ssthresh       = tcp_reno_ssthresh,
+       .cong_avoid     = mptcp_wvegas_cong_avoid,
+       .min_cwnd       = tcp_reno_min_cwnd,
+       .pkts_acked     = mptcp_wvegas_pkts_acked,
+       .set_state      = mptcp_wvegas_state,
+       .cwnd_event     = mptcp_wvegas_cwnd_event,
+
+       .owner          = THIS_MODULE,
+       .name           = "wvegas",
+};
+
+static int __init mptcp_wvegas_register(void)
+{
+       BUILD_BUG_ON(sizeof(struct wvegas) > ICSK_CA_PRIV_SIZE);
+       tcp_register_congestion_control(&mptcp_wvegas);
+       return 0;
+}
+
+static void __exit mptcp_wvegas_unregister(void)
+{
+       tcp_unregister_congestion_control(&mptcp_wvegas);
+}
+
+module_init(mptcp_wvegas_register);
+module_exit(mptcp_wvegas_unregister);
+
+MODULE_AUTHOR("Yu Cao, Enhuan Dong");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MPTCP wVegas");
+MODULE_VERSION("0.1");