net/l2tp/l2tp_core.h

   1 /*
   2  * L2TP internal definitions.
   3  *
   4  * Copyright (c) 2008,2009 Katalix Systems Ltd
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #ifndef _L2TP_CORE_H_
  12 #define _L2TP_CORE_H_
  13
  14 /* Just some random numbers */
  15 #define L2TP_TUNNEL_MAGIC       0x42114DDA
  16 #define L2TP_SESSION_MAGIC      0x0C04EB7D
  17
  18 /* Per tunnel, session hash table size */
  19 #define L2TP_HASH_BITS  4
  20 #define L2TP_HASH_SIZE  (1 << L2TP_HASH_BITS)
  21
  22 /* System-wide, session hash table size */
  23 #define L2TP_HASH_BITS_2        8
  24 #define L2TP_HASH_SIZE_2        (1 << L2TP_HASH_BITS_2)
  25
  26 struct sk_buff;
  27
  28 struct l2tp_stats {
  29         atomic_long_t           tx_packets;
  30         atomic_long_t           tx_bytes;
  31         atomic_long_t           tx_errors;
  32         atomic_long_t           rx_packets;
  33         atomic_long_t           rx_bytes;
  34         atomic_long_t           rx_seq_discards;
  35         atomic_long_t           rx_oos_packets;
  36         atomic_long_t           rx_errors;
  37         atomic_long_t           rx_cookie_discards;
  38 };
  39
  40 struct l2tp_tunnel;
  41
  42 /* Describes a session. Contains information to determine incoming
  43  * packets and transmit outgoing ones.
  44  */
  45 struct l2tp_session_cfg {
  46         enum l2tp_pwtype        pw_type;
  47         unsigned int            data_seq:2;     /* data sequencing level
  48                                                  * 0 => none, 1 => IP only,
  49                                                  * 2 => all
  50                                                  */
  51         unsigned int            recv_seq:1;     /* expect receive packets with
  52                                                  * sequence numbers? */
  53         unsigned int            send_seq:1;     /* send packets with sequence
  54                                                  * numbers? */
  55         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
  56                                                  * sequence numbers under
  57                                                  * control of LNS. */
  58         int                     debug;          /* bitmask of debug message
  59                                                  * categories */
  60         u16                     vlan_id;        /* VLAN pseudowire only */
  61         u16                     offset;         /* offset to payload */
  62         u16                     l2specific_len; /* Layer 2 specific length */
  63         u16                     l2specific_type; /* Layer 2 specific type */
  64         u8                      cookie[8];      /* optional cookie */
  65         int                     cookie_len;     /* 0, 4 or 8 bytes */
  66         u8                      peer_cookie[8]; /* peer's cookie */
  67         int                     peer_cookie_len; /* 0, 4 or 8 bytes */
  68         int                     reorder_timeout; /* configured reorder timeout
  69                                                   * (in jiffies) */
  70         int                     mtu;
  71         int                     mru;
  72         char                    *ifname;
  73 };
  74
  75 struct l2tp_session {
  76         int                     magic;          /* should be
  77                                                  * L2TP_SESSION_MAGIC */
  78
  79         struct l2tp_tunnel      *tunnel;        /* back pointer to tunnel
  80                                                  * context */
  81         u32                     session_id;
  82         u32                     peer_session_id;
  83         u8                      cookie[8];
  84         int                     cookie_len;
  85         u8                      peer_cookie[8];
  86         int                     peer_cookie_len;
  87         u16                     offset;         /* offset from end of L2TP header
  88                                                    to beginning of data */
  89         u16                     l2specific_len;
  90         u16                     l2specific_type;
  91         u16                     hdr_len;
  92         u32                     nr;             /* session NR state (receive) */
  93         u32                     ns;             /* session NR state (send) */
  94         struct sk_buff_head     reorder_q;      /* receive reorder queue */
  95         u32                     nr_max;         /* max NR. Depends on tunnel */
  96         u32                     nr_window_size; /* NR window size */
  97         u32                     nr_oos;         /* NR of last OOS packet */
  98         int                     nr_oos_count;   /* For OOS recovery */
  99         int                     nr_oos_count_max;
 100         struct hlist_node       hlist;          /* Hash list node */
 101         atomic_t                ref_count;
 102
 103         char                    name[32];       /* for logging */
 104         char                    ifname[IFNAMSIZ];
 105         unsigned int            data_seq:2;     /* data sequencing level
 106                                                  * 0 => none, 1 => IP only,
 107                                                  * 2 => all
 108                                                  */
 109         unsigned int            recv_seq:1;     /* expect receive packets with
 110                                                  * sequence numbers? */
 111         unsigned int            send_seq:1;     /* send packets with sequence
 112                                                  * numbers? */
 113         unsigned int            lns_mode:1;     /* behave as LNS? LAC enables
 114                                                  * sequence numbers under
 115                                                  * control of LNS. */
 116         int                     debug;          /* bitmask of debug message
 117                                                  * categories */
 118         int                     reorder_timeout; /* configured reorder timeout
 119                                                   * (in jiffies) */
 120         int                     reorder_skip;   /* set if skip to next nr */
 121         int                     mtu;
 122         int                     mru;
 123         enum l2tp_pwtype        pwtype;
 124         struct l2tp_stats       stats;
 125         struct hlist_node       global_hlist;   /* Global hash list node */
 126
 127         int (*build_header)(struct l2tp_session *session, void *buf);
 128         void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 129         void (*session_close)(struct l2tp_session *session);
 130         void (*ref)(struct l2tp_session *session);
 131         void (*deref)(struct l2tp_session *session);
 132 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 133         void (*show)(struct seq_file *m, void *priv);
 134 #endif
 135         uint8_t                 priv[0];        /* private data */
 136 };
 137
 138 /* Describes the tunnel. It contains info to track all the associated
 139  * sessions so incoming packets can be sorted out
 140  */
 141 struct l2tp_tunnel_cfg {
 142         int                     debug;          /* bitmask of debug message
 143                                                  * categories */
 144         enum l2tp_encap_type    encap;
 145
 146         /* Used only for kernel-created sockets */
 147         struct in_addr          local_ip;
 148         struct in_addr          peer_ip;
 149 #if IS_ENABLED(CONFIG_IPV6)
 150         struct in6_addr         *local_ip6;
 151         struct in6_addr         *peer_ip6;
 152 #endif
 153         u16                     local_udp_port;
 154         u16                     peer_udp_port;
 155         unsigned int            use_udp_checksums:1,
 156                                 udp6_zero_tx_checksums:1,
 157                                 udp6_zero_rx_checksums:1;
 158 };
 159
 160 struct l2tp_tunnel {
 161         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 162         struct rcu_head rcu;
 163         rwlock_t                hlist_lock;     /* protect session_hlist */
 164         struct hlist_head       session_hlist[L2TP_HASH_SIZE];
 165                                                 /* hashed list of sessions,
 166                                                  * hashed by id */
 167         u32                     tunnel_id;
 168         u32                     peer_tunnel_id;
 169         int                     version;        /* 2=>L2TPv2, 3=>L2TPv3 */
 170
 171         char                    name[20];       /* for logging */
 172         int                     debug;          /* bitmask of debug message
 173                                                  * categories */
 174         enum l2tp_encap_type    encap;
 175         struct l2tp_stats       stats;
 176
 177         struct list_head        list;           /* Keep a list of all tunnels */
 178         struct net              *l2tp_net;      /* the net we belong to */
 179
 180         atomic_t                ref_count;
 181 #ifdef CONFIG_DEBUG_FS
 182         void (*show)(struct seq_file *m, void *arg);
 183 #endif
 184         int (*recv_payload_hook)(struct sk_buff *skb);
 185         void (*old_sk_destruct)(struct sock *);
 186         struct sock             *sock;          /* Parent socket */
 187         int                     fd;             /* Parent fd, if tunnel socket
 188                                                  * was created by userspace */
 189 #if IS_ENABLED(CONFIG_IPV6)
 190         bool                    v4mapped;
 191 #endif
 192
 193         struct work_struct      del_work;
 194
 195         uint8_t                 priv[0];        /* private data */
 196 };
 197
 198 struct l2tp_nl_cmd_ops {
 199         int (*session_create)(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg);
 200         int (*session_delete)(struct l2tp_session *session);
 201 };
 202
 203 static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
 204 {
 205         return &tunnel->priv[0];
 206 }
 207
 208 static inline void *l2tp_session_priv(struct l2tp_session *session)
 209 {
 210         return &session->priv[0];
 211 }
 212
 213 static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 214 {
 215         struct l2tp_tunnel *tunnel;
 216
 217         if (sk == NULL)
 218                 return NULL;
 219
 220         sock_hold(sk);
 221         tunnel = (struct l2tp_tunnel *)(sk->sk_user_data);
 222         if (tunnel == NULL) {
 223                 sock_put(sk);
 224                 goto out;
 225         }
 226
 227         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 228
 229 out:
 230         return tunnel;
 231 }
 232
 233 struct l2tp_session *l2tp_session_find(struct net *net,
 234                                        struct l2tp_tunnel *tunnel,
 235                                        u32 session_id);
 236 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
 237 struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
 238 struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
 239 struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth);
 240
 241 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
 242                        u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
 243                        struct l2tp_tunnel **tunnelp);
 244 void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
 245 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
 246 struct l2tp_session *l2tp_session_create(int priv_size,
 247                                          struct l2tp_tunnel *tunnel,
 248                                          u32 session_id, u32 peer_session_id,
 249                                          struct l2tp_session_cfg *cfg);
 250 void __l2tp_session_unhash(struct l2tp_session *session);
 251 int l2tp_session_delete(struct l2tp_session *session);
 252 void l2tp_session_free(struct l2tp_session *session);
 253 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 254                       unsigned char *ptr, unsigned char *optr, u16 hdrflags,
 255                       int length, int (*payload_hook)(struct sk_buff *skb));
 256 int l2tp_session_queue_purge(struct l2tp_session *session);
 257 int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
 258 void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 259
 260 int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
 261                   int hdr_len);
 262
 263 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
 264                          const struct l2tp_nl_cmd_ops *ops);
 265 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 266 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 267
 268 /* Session reference counts. Incremented when code obtains a reference
 269  * to a session.
 270  */
 271 static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
 272 {
 273         atomic_inc(&session->ref_count);
 274 }
 275
 276 static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
 277 {
 278         if (atomic_dec_and_test(&session->ref_count))
 279                 l2tp_session_free(session);
 280 }
 281
 282 #ifdef L2TP_REFCNT_DEBUG
 283 #define l2tp_session_inc_refcount(_s)                                   \
 284 do {                                                                    \
 285         pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",       \
 286                  __func__, __LINE__, (_s)->name,                        \
 287                  atomic_read(&_s->ref_count));                          \
 288         l2tp_session_inc_refcount_1(_s);                                \
 289 } while (0)
 290 #define l2tp_session_dec_refcount(_s)                                   \
 291 do {                                                                    \
 292         pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",       \
 293                  __func__, __LINE__, (_s)->name,                        \
 294                  atomic_read(&_s->ref_count));                          \
 295         l2tp_session_dec_refcount_1(_s);                                \
 296 } while (0)
 297 #else
 298 #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
 299 #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
 300 #endif
 301
 302 #define l2tp_printk(ptr, type, func, fmt, ...)                          \
 303 do {                                                                    \
 304         if (((ptr)->debug) & (type))                                    \
 305                 func(fmt, ##__VA_ARGS__);                               \
 306 } while (0)
 307
 308 #define l2tp_warn(ptr, type, fmt, ...)                                  \
 309         l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
 310 #define l2tp_info(ptr, type, fmt, ...)                                  \
 311         l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
 312 #define l2tp_dbg(ptr, type, fmt, ...)                                   \
 313         l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
 314
 315 #define MODULE_ALIAS_L2TP_PWTYPE(type) \
 316         MODULE_ALIAS("net-l2tp-type-" __stringify(type))
 317
 318 #endif /* _L2TP_CORE_H_ */