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 <linux/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 struct inet_bind_bucket;
  92
  93 /*
  94  * This is a TIME_WAIT sock. It works around the memory consumption
  95  * problems of sockets in such a state on heavily loaded servers, but
  96  * without violating the protocol specification.
  97  */
  98 struct inet_timewait_sock {
  99         /*
 100          * Now struct sock also uses sock_common, so please just
 101          * don't add nothing before this first member (__tw_common) --acme
 102          */
 103         struct sock_common      __tw_common;
 104 #define tw_family               __tw_common.skc_family
 105 #define tw_state                __tw_common.skc_state
 106 #define tw_reuse                __tw_common.skc_reuse
 107 #define tw_bound_dev_if         __tw_common.skc_bound_dev_if
 108 #define tw_node                 __tw_common.skc_nulls_node
 109 #define tw_bind_node            __tw_common.skc_bind_node
 110 #define tw_refcnt               __tw_common.skc_refcnt
 111 #define tw_hash                 __tw_common.skc_hash
 112 #define tw_prot                 __tw_common.skc_prot
 113 #define tw_net                  __tw_common.skc_net
 114 #define tw_daddr                __tw_common.skc_daddr
 115 #define tw_rcv_saddr            __tw_common.skc_rcv_saddr
 116         int                     tw_timeout;
 117         volatile unsigned char  tw_substate;
 118         unsigned char           tw_rcv_wscale;
 119
 120         /* Socket demultiplex comparisons on incoming packets. */
 121         /* these three are in inet_sock */
 122         __be16                  tw_sport;
 123         __be16                  tw_dport;
 124         __u16                   tw_num;
 125         kmemcheck_bitfield_begin(flags);
 126         /* And these are ours. */
 127         unsigned int            tw_ipv6only     : 1,
 128                                 tw_transparent  : 1,
 129                                 tw_pad          : 14,   /* 14 bits hole */
 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
 137 static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
 138                                       struct hlist_nulls_head *list)
 139 {
 140         hlist_nulls_add_head_rcu(&tw->tw_node, list);
 141 }
 142
 143 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
 144                                            struct hlist_head *list)
 145 {
 146         hlist_add_head(&tw->tw_bind_node, list);
 147 }
 148
 149 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 150 {
 151         return !hlist_unhashed(&tw->tw_death_node);
 152 }
 153
 154 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 155 {
 156         tw->tw_death_node.pprev = NULL;
 157 }
 158
 159 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 160 {
 161         __hlist_del(&tw->tw_death_node);
 162         inet_twsk_dead_node_init(tw);
 163 }
 164
 165 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 166 {
 167         if (inet_twsk_dead_hashed(tw)) {
 168                 __inet_twsk_del_dead_node(tw);
 169                 return 1;
 170         }
 171         return 0;
 172 }
 173
 174 #define inet_twsk_for_each(tw, node, head) \
 175         hlist_nulls_for_each_entry(tw, node, head, tw_node)
 176
 177 #define inet_twsk_for_each_inmate(tw, node, jail) \
 178         hlist_for_each_entry(tw, node, jail, tw_death_node)
 179
 180 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
 181         hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
 182
 183 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 184 {
 185         return (struct inet_timewait_sock *)sk;
 186 }
 187
 188 static inline __be32 sk_rcv_saddr(const struct sock *sk)
 189 {
 190 /* both inet_sk() and inet_twsk() store rcv_saddr in skc_rcv_saddr */
 191         return sk->__sk_common.skc_rcv_saddr;
 192 }
 193
 194 extern void inet_twsk_put(struct inet_timewait_sock *tw);
 195
 196 extern int inet_twsk_unhash(struct inet_timewait_sock *tw);
 197
 198 extern int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
 199                                  struct inet_hashinfo *hashinfo);
 200
 201 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 202                                                   const int state);
 203
 204 extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
 205                                   struct sock *sk,
 206                                   struct inet_hashinfo *hashinfo);
 207
 208 extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
 209                                struct inet_timewait_death_row *twdr,
 210                                const int timeo, const int timewait_len);
 211 extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 212                                  struct inet_timewait_death_row *twdr);
 213
 214 extern void inet_twsk_purge(struct inet_hashinfo *hashinfo,
 215                             struct inet_timewait_death_row *twdr, int family);
 216
 217 static inline
 218 struct net *twsk_net(const struct inet_timewait_sock *twsk)
 219 {
 220 #ifdef CONFIG_NET_NS
 221         return rcu_dereference_raw(twsk->tw_net); /* protected by locking, */
 222                                                   /* reference counting, */
 223                                                   /* initialization, or RCU. */
 224 #else
 225         return &init_net;
 226 #endif
 227 }
 228
 229 static inline
 230 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
 231 {
 232 #ifdef CONFIG_NET_NS
 233         rcu_assign_pointer(twsk->tw_net, net);
 234 #endif
 235 }
 236 #endif  /* _INET_TIMEWAIT_SOCK_ */