include/net/inet_timewait_sock.h

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Definitions for a generic INET TIMEWAIT sock
   7  *
   8  *              From code originally in net/tcp.h
   9  *
  10  *              This program is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or (at your option) any later version.
  14  */
  15 #ifndef _INET_TIMEWAIT_SOCK_
  16 #define _INET_TIMEWAIT_SOCK_
  17
  18
  19 #include <linux/kmemcheck.h>
  20 #include <linux/list.h>
  21 #include <linux/timer.h>
  22 #include <linux/types.h>
  23 #include <linux/workqueue.h>
  24
  25 #include <net/inet_sock.h>
  26 #include <net/sock.h>
  27 #include <net/tcp_states.h>
  28 #include <net/timewait_sock.h>
  29
  30 #include <linux/atomic.h>
  31
  32 struct inet_hashinfo;
  33
  34 #define INET_TWDR_RECYCLE_SLOTS_LOG     5
  35 #define INET_TWDR_RECYCLE_SLOTS         (1 << INET_TWDR_RECYCLE_SLOTS_LOG)
  36
  37 /*
  38  * If time > 4sec, it is "slow" path, no recycling is required,
  39  * so that we select tick to get range about 4 seconds.
  40  */
  41 #if HZ <= 16 || HZ > 4096
  42 # error Unsupported: HZ <= 16 or HZ > 4096
  43 #elif HZ <= 32
  44 # define INET_TWDR_RECYCLE_TICK (5 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  45 #elif HZ <= 64
  46 # define INET_TWDR_RECYCLE_TICK (6 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  47 #elif HZ <= 128
  48 # define INET_TWDR_RECYCLE_TICK (7 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  49 #elif HZ <= 256
  50 # define INET_TWDR_RECYCLE_TICK (8 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  51 #elif HZ <= 512
  52 # define INET_TWDR_RECYCLE_TICK (9 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  53 #elif HZ <= 1024
  54 # define INET_TWDR_RECYCLE_TICK (10 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  55 #elif HZ <= 2048
  56 # define INET_TWDR_RECYCLE_TICK (11 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  57 #else
  58 # define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  59 #endif
  60
  61 /* TIME_WAIT reaping mechanism. */
  62 #define INET_TWDR_TWKILL_SLOTS  8 /* Please keep this a power of 2. */
  63
  64 #define INET_TWDR_TWKILL_QUOTA 100
  65
  66 struct inet_timewait_death_row {
  67         /* Short-time timewait calendar */
  68         int                     twcal_hand;
  69         unsigned long           twcal_jiffie;
  70         struct timer_list       twcal_timer;
  71         struct hlist_head       twcal_row[INET_TWDR_RECYCLE_SLOTS];
  72
  73         spinlock_t              death_lock;
  74         int                     tw_count;
  75         int                     period;
  76         u32                     thread_slots;
  77         struct work_struct      twkill_work;
  78         struct timer_list       tw_timer;
  79         int                     slot;
  80         struct hlist_head       cells[INET_TWDR_TWKILL_SLOTS];
  81         struct inet_hashinfo    *hashinfo;
  82         int                     sysctl_tw_recycle;
  83         int                     sysctl_max_tw_buckets;
  84 };
  85
  86 extern void inet_twdr_hangman(unsigned long data);
  87 extern void inet_twdr_twkill_work(struct work_struct *work);
  88 extern void inet_twdr_twcal_tick(unsigned long data);
  89
  90 struct inet_bind_bucket;
  91
  92 /*
  93  * This is a TIME_WAIT sock. It works around the memory consumption
  94  * problems of sockets in such a state on heavily loaded servers, but
  95  * without violating the protocol specification.
  96  */
  97 struct inet_timewait_sock {
  98         /*
  99          * Now struct sock also uses sock_common, so please just
 100          * don't add nothing before this first member (__tw_common) --acme
 101          */
 102         struct sock_common      __tw_common;
 103 #define tw_family               __tw_common.skc_family
 104 #define tw_state                __tw_common.skc_state
 105 #define tw_reuse                __tw_common.skc_reuse
 106 #define tw_bound_dev_if         __tw_common.skc_bound_dev_if
 107 #define tw_node                 __tw_common.skc_nulls_node
 108 #define tw_bind_node            __tw_common.skc_bind_node
 109 #define tw_refcnt               __tw_common.skc_refcnt
 110 #define tw_hash                 __tw_common.skc_hash
 111 #define tw_prot                 __tw_common.skc_prot
 112 #define tw_net                  __tw_common.skc_net
 113 #define tw_daddr                __tw_common.skc_daddr
 114 #define tw_rcv_saddr            __tw_common.skc_rcv_saddr
 115         int                     tw_timeout;
 116         volatile unsigned char  tw_substate;
 117         unsigned char           tw_rcv_wscale;
 118
 119         /* Socket demultiplex comparisons on incoming packets. */
 120         /* these three are in inet_sock */
 121         __be16                  tw_sport;
 122         __be16                  tw_dport;
 123         __u16                   tw_num;
 124         kmemcheck_bitfield_begin(flags);
 125         /* And these are ours. */
 126         unsigned int            tw_ipv6only     : 1,
 127                                 tw_transparent  : 1,
 128                                 tw_pad          : 6,    /* 6 bits hole */
 129                                 tw_tos          : 8,
 130                                 tw_ipv6_offset  : 16;
 131         kmemcheck_bitfield_end(flags);
 132         unsigned long           tw_ttd;
 133         struct inet_bind_bucket *tw_tb;
 134         struct hlist_node       tw_death_node;
 135 };
 136 #define tw_tclass tw_tos
 137
 138 static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
 139                                       struct hlist_nulls_head *list)
 140 {
 141         hlist_nulls_add_head_rcu(&tw->tw_node, list);
 142 }
 143
 144 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
 145                                            struct hlist_head *list)
 146 {
 147         hlist_add_head(&tw->tw_bind_node, list);
 148 }
 149
 150 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 151 {
 152         return !hlist_unhashed(&tw->tw_death_node);
 153 }
 154
 155 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 156 {
 157         tw->tw_death_node.pprev = NULL;
 158 }
 159
 160 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 161 {
 162         __hlist_del(&tw->tw_death_node);
 163         inet_twsk_dead_node_init(tw);
 164 }
 165
 166 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 167 {
 168         if (inet_twsk_dead_hashed(tw)) {
 169                 __inet_twsk_del_dead_node(tw);
 170                 return 1;
 171         }
 172         return 0;
 173 }
 174
 175 #define inet_twsk_for_each(tw, node, head) \
 176         hlist_nulls_for_each_entry(tw, node, head, tw_node)
 177
 178 #define inet_twsk_for_each_inmate(tw, node, jail) \
 179         hlist_for_each_entry(tw, node, jail, tw_death_node)
 180
 181 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
 182         hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
 183
 184 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 185 {
 186         return (struct inet_timewait_sock *)sk;
 187 }
 188
 189 static inline __be32 sk_rcv_saddr(const struct sock *sk)
 190 {
 191 /* both inet_sk() and inet_twsk() store rcv_saddr in skc_rcv_saddr */
 192         return sk->__sk_common.skc_rcv_saddr;
 193 }
 194
 195 extern void inet_twsk_put(struct inet_timewait_sock *tw);
 196
 197 extern int inet_twsk_unhash(struct inet_timewait_sock *tw);
 198
 199 extern int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
 200                                  struct inet_hashinfo *hashinfo);
 201
 202 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 203                                                   const int state);
 204
 205 extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
 206                                   struct sock *sk,
 207                                   struct inet_hashinfo *hashinfo);
 208
 209 extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
 210                                struct inet_timewait_death_row *twdr,
 211                                const int timeo, const int timewait_len);
 212 extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 213                                  struct inet_timewait_death_row *twdr);
 214
 215 extern void inet_twsk_purge(struct inet_hashinfo *hashinfo,
 216                             struct inet_timewait_death_row *twdr, int family);
 217
 218 static inline
 219 struct net *twsk_net(const struct inet_timewait_sock *twsk)
 220 {
 221 #ifdef CONFIG_NET_NS
 222         return rcu_dereference_raw(twsk->tw_net); /* protected by locking, */
 223                                                   /* reference counting, */
 224                                                   /* initialization, or RCU. */
 225 #else
 226         return &init_net;
 227 #endif
 228 }
 229
 230 static inline
 231 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
 232 {
 233 #ifdef CONFIG_NET_NS
 234         rcu_assign_pointer(twsk->tw_net, net);
 235 #endif
 236 }
 237 #endif  /* _INET_TIMEWAIT_SOCK_ */