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/module.h>
  22 #include <linux/timer.h>
  23 #include <linux/types.h>
  24 #include <linux/workqueue.h>
  25
  26 #include <net/inet_sock.h>
  27 #include <net/sock.h>
  28 #include <net/tcp_states.h>
  29 #include <net/timewait_sock.h>
  30
  31 #include <asm/atomic.h>
  32
  33 struct inet_hashinfo;
  34
  35 #define INET_TWDR_RECYCLE_SLOTS_LOG     5
  36 #define INET_TWDR_RECYCLE_SLOTS         (1 << INET_TWDR_RECYCLE_SLOTS_LOG)
  37
  38 /*
  39  * If time > 4sec, it is "slow" path, no recycling is required,
  40  * so that we select tick to get range about 4 seconds.
  41  */
  42 #if HZ <= 16 || HZ > 4096
  43 # error Unsupported: HZ <= 16 or HZ > 4096
  44 #elif HZ <= 32
  45 # define INET_TWDR_RECYCLE_TICK (5 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  46 #elif HZ <= 64
  47 # define INET_TWDR_RECYCLE_TICK (6 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  48 #elif HZ <= 128
  49 # define INET_TWDR_RECYCLE_TICK (7 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  50 #elif HZ <= 256
  51 # define INET_TWDR_RECYCLE_TICK (8 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  52 #elif HZ <= 512
  53 # define INET_TWDR_RECYCLE_TICK (9 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  54 #elif HZ <= 1024
  55 # define INET_TWDR_RECYCLE_TICK (10 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  56 #elif HZ <= 2048
  57 # define INET_TWDR_RECYCLE_TICK (11 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  58 #else
  59 # define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  60 #endif
  61
  62 /* TIME_WAIT reaping mechanism. */
  63 #define INET_TWDR_TWKILL_SLOTS  8 /* Please keep this a power of 2. */
  64
  65 #define INET_TWDR_TWKILL_QUOTA 100
  66
  67 struct inet_timewait_death_row {
  68         /* Short-time timewait calendar */
  69         int                     twcal_hand;
  70         unsigned long           twcal_jiffie;
  71         struct timer_list       twcal_timer;
  72         struct hlist_head       twcal_row[INET_TWDR_RECYCLE_SLOTS];
  73
  74         spinlock_t              death_lock;
  75         int                     tw_count;
  76         int                     period;
  77         u32                     thread_slots;
  78         struct work_struct      twkill_work;
  79         struct timer_list       tw_timer;
  80         int                     slot;
  81         struct hlist_head       cells[INET_TWDR_TWKILL_SLOTS];
  82         struct inet_hashinfo    *hashinfo;
  83         int                     sysctl_tw_recycle;
  84         int                     sysctl_max_tw_buckets;
  85 };
  86
  87 extern void inet_twdr_hangman(unsigned long data);
  88 extern void inet_twdr_twkill_work(struct work_struct *work);
  89 extern void inet_twdr_twcal_tick(unsigned long data);
  90
  91 #if (BITS_PER_LONG == 64)
  92 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8
  93 #else
  94 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 4
  95 #endif
  96
  97 struct inet_bind_bucket;
  98
  99 /*
 100  * This is a TIME_WAIT sock. It works around the memory consumption
 101  * problems of sockets in such a state on heavily loaded servers, but
 102  * without violating the protocol specification.
 103  */
 104 struct inet_timewait_sock {
 105         /*
 106          * Now struct sock also uses sock_common, so please just
 107          * don't add nothing before this first member (__tw_common) --acme
 108          */
 109         struct sock_common      __tw_common;
 110 #define tw_family               __tw_common.skc_family
 111 #define tw_state                __tw_common.skc_state
 112 #define tw_reuse                __tw_common.skc_reuse
 113 #define tw_bound_dev_if         __tw_common.skc_bound_dev_if
 114 #define tw_node                 __tw_common.skc_nulls_node
 115 #define tw_bind_node            __tw_common.skc_bind_node
 116 #define tw_refcnt               __tw_common.skc_refcnt
 117 #define tw_hash                 __tw_common.skc_hash
 118 #define tw_prot                 __tw_common.skc_prot
 119 #define tw_net                  __tw_common.skc_net
 120         int                     tw_timeout;
 121         volatile unsigned char  tw_substate;
 122         /* 3 bits hole, try to pack */
 123         unsigned char           tw_rcv_wscale;
 124         /* Socket demultiplex comparisons on incoming packets. */
 125         /* these five are in inet_sock */
 126         __be16                  tw_sport;
 127         __be32                  tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
 128         __be32                  tw_rcv_saddr;
 129         __be16                  tw_dport;
 130         __u16                   tw_num;
 131         kmemcheck_bitfield_begin(flags);
 132         /* And these are ours. */
 133         unsigned int            tw_ipv6only     : 1,
 134                                 tw_transparent  : 1,
 135                                 tw_pad          : 14,   /* 14 bits hole */
 136                                 tw_ipv6_offset  : 16;
 137         kmemcheck_bitfield_end(flags);
 138         unsigned long           tw_ttd;
 139         struct inet_bind_bucket *tw_tb;
 140         struct hlist_node       tw_death_node;
 141 };
 142
 143 static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
 144                                       struct hlist_nulls_head *list)
 145 {
 146         hlist_nulls_add_head_rcu(&tw->tw_node, list);
 147 }
 148
 149 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
 150                                            struct hlist_head *list)
 151 {
 152         hlist_add_head(&tw->tw_bind_node, list);
 153 }
 154
 155 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 156 {
 157         return !hlist_unhashed(&tw->tw_death_node);
 158 }
 159
 160 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 161 {
 162         tw->tw_death_node.pprev = NULL;
 163 }
 164
 165 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 166 {
 167         __hlist_del(&tw->tw_death_node);
 168         inet_twsk_dead_node_init(tw);
 169 }
 170
 171 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 172 {
 173         if (inet_twsk_dead_hashed(tw)) {
 174                 __inet_twsk_del_dead_node(tw);
 175                 return 1;
 176         }
 177         return 0;
 178 }
 179
 180 #define inet_twsk_for_each(tw, node, head) \
 181         hlist_nulls_for_each_entry(tw, node, head, tw_node)
 182
 183 #define inet_twsk_for_each_inmate(tw, node, jail) \
 184         hlist_for_each_entry(tw, node, jail, tw_death_node)
 185
 186 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
 187         hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
 188
 189 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 190 {
 191         return (struct inet_timewait_sock *)sk;
 192 }
 193
 194 static inline __be32 inet_rcv_saddr(const struct sock *sk)
 195 {
 196         return likely(sk->sk_state != TCP_TIME_WAIT) ?
 197                 inet_sk(sk)->inet_rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
 198 }
 199
 200 extern void inet_twsk_put(struct inet_timewait_sock *tw);
 201
 202 extern int inet_twsk_unhash(struct inet_timewait_sock *tw);
 203
 204 extern int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
 205                                  struct inet_hashinfo *hashinfo);
 206
 207 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 208                                                   const int state);
 209
 210 extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
 211                                   struct sock *sk,
 212                                   struct inet_hashinfo *hashinfo);
 213
 214 extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
 215                                struct inet_timewait_death_row *twdr,
 216                                const int timeo, const int timewait_len);
 217 extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 218                                  struct inet_timewait_death_row *twdr);
 219
 220 extern void inet_twsk_purge(struct inet_hashinfo *hashinfo,
 221                             struct inet_timewait_death_row *twdr, int family);
 222
 223 static inline
 224 struct net *twsk_net(const struct inet_timewait_sock *twsk)
 225 {
 226 #ifdef CONFIG_NET_NS
 227         return rcu_dereference_raw(twsk->tw_net); /* protected by locking, */
 228                                                   /* reference counting, */
 229                                                   /* initialization, or RCU. */
 230 #else
 231         return &init_net;
 232 #endif
 233 }
 234
 235 static inline
 236 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
 237 {
 238 #ifdef CONFIG_NET_NS
 239         rcu_assign_pointer(twsk->tw_net, net);
 240 #endif
 241 }
 242 #endif  /* _INET_TIMEWAIT_SOCK_ */