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 #include <linux/config.h>
  19
  20 #include <linux/ip.h>
  21 #include <linux/list.h>
  22 #include <linux/timer.h>
  23 #include <linux/types.h>
  24 #include <linux/workqueue.h>
  25
  26 #include <net/sock.h>
  27 #include <net/tcp_states.h>
  28
  29 #include <asm/atomic.h>
  30
  31 struct inet_hashinfo;
  32
  33 #define INET_TWDR_RECYCLE_SLOTS_LOG     5
  34 #define INET_TWDR_RECYCLE_SLOTS         (1 << INET_TWDR_RECYCLE_SLOTS_LOG)
  35
  36 /*
  37  * If time > 4sec, it is "slow" path, no recycling is required,
  38  * so that we select tick to get range about 4 seconds.
  39  */
  40 #if HZ <= 16 || HZ > 4096
  41 # error Unsupported: HZ <= 16 or HZ > 4096
  42 #elif HZ <= 32
  43 # define INET_TWDR_RECYCLE_TICK (5 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  44 #elif HZ <= 64
  45 # define INET_TWDR_RECYCLE_TICK (6 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  46 #elif HZ <= 128
  47 # define INET_TWDR_RECYCLE_TICK (7 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  48 #elif HZ <= 256
  49 # define INET_TWDR_RECYCLE_TICK (8 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  50 #elif HZ <= 512
  51 # define INET_TWDR_RECYCLE_TICK (9 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  52 #elif HZ <= 1024
  53 # define INET_TWDR_RECYCLE_TICK (10 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  54 #elif HZ <= 2048
  55 # define INET_TWDR_RECYCLE_TICK (11 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  56 #else
  57 # define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
  58 #endif
  59
  60 /* TIME_WAIT reaping mechanism. */
  61 #define INET_TWDR_TWKILL_SLOTS  8 /* Please keep this a power of 2. */
  62
  63 #define INET_TWDR_TWKILL_QUOTA 100
  64
  65 struct inet_timewait_death_row {
  66         /* Short-time timewait calendar */
  67         int                     twcal_hand;
  68         int                     twcal_jiffie;
  69         struct timer_list       twcal_timer;
  70         struct hlist_head       twcal_row[INET_TWDR_RECYCLE_SLOTS];
  71
  72         spinlock_t              death_lock;
  73         int                     tw_count;
  74         int                     period;
  75         u32                     thread_slots;
  76         struct work_struct      twkill_work;
  77         struct timer_list       tw_timer;
  78         int                     slot;
  79         struct hlist_head       cells[INET_TWDR_TWKILL_SLOTS];
  80         struct inet_hashinfo    *hashinfo;
  81         int                     sysctl_tw_recycle;
  82         int                     sysctl_max_tw_buckets;
  83 };
  84
  85 extern void inet_twdr_hangman(unsigned long data);
  86 extern void inet_twdr_twkill_work(void *data);
  87 extern void inet_twdr_twcal_tick(unsigned long data);
  88
  89 #if (BITS_PER_LONG == 64)
  90 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8
  91 #else
  92 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 4
  93 #endif
  94
  95 struct inet_bind_bucket;
  96
  97 /*
  98  * This is a TIME_WAIT sock. It works around the memory consumption
  99  * problems of sockets in such a state on heavily loaded servers, but
 100  * without violating the protocol specification.
 101  */
 102 struct inet_timewait_sock {
 103         /*
 104          * Now struct sock also uses sock_common, so please just
 105          * don't add nothing before this first member (__tw_common) --acme
 106          */
 107         struct sock_common      __tw_common;
 108 #define tw_family               __tw_common.skc_family
 109 #define tw_state                __tw_common.skc_state
 110 #define tw_reuse                __tw_common.skc_reuse
 111 #define tw_bound_dev_if         __tw_common.skc_bound_dev_if
 112 #define tw_node                 __tw_common.skc_node
 113 #define tw_bind_node            __tw_common.skc_bind_node
 114 #define tw_refcnt               __tw_common.skc_refcnt
 115 #define tw_prot                 __tw_common.skc_prot
 116         volatile unsigned char  tw_substate;
 117         /* 3 bits hole, try to pack */
 118         unsigned char           tw_rcv_wscale;
 119         /* Socket demultiplex comparisons on incoming packets. */
 120         /* these five are in inet_sock */
 121         __u16                   tw_sport;
 122         __u32                   tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
 123         __u32                   tw_rcv_saddr;
 124         __u16                   tw_dport;
 125         __u16                   tw_num;
 126         /* And these are ours. */
 127         __u8                    tw_ipv6only:1;
 128         /* 31 bits hole, try to pack */
 129         int                     tw_hashent;
 130         int                     tw_timeout;
 131         unsigned long           tw_ttd;
 132         struct inet_bind_bucket *tw_tb;
 133         struct hlist_node       tw_death_node;
 134 };
 135
 136 static inline void inet_twsk_add_node(struct inet_timewait_sock *tw,
 137                                       struct hlist_head *list)
 138 {
 139         hlist_add_head(&tw->tw_node, list);
 140 }
 141
 142 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
 143                                            struct hlist_head *list)
 144 {
 145         hlist_add_head(&tw->tw_bind_node, list);
 146 }
 147
 148 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 149 {
 150         return tw->tw_death_node.pprev != NULL;
 151 }
 152
 153 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 154 {
 155         tw->tw_death_node.pprev = NULL;
 156 }
 157
 158 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 159 {
 160         __hlist_del(&tw->tw_death_node);
 161         inet_twsk_dead_node_init(tw);
 162 }
 163
 164 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 165 {
 166         if (inet_twsk_dead_hashed(tw)) {
 167                 __inet_twsk_del_dead_node(tw);
 168                 return 1;
 169         }
 170         return 0;
 171 }
 172
 173 #define inet_twsk_for_each(tw, node, head) \
 174         hlist_for_each_entry(tw, node, head, tw_node)
 175
 176 #define inet_twsk_for_each_inmate(tw, node, jail) \
 177         hlist_for_each_entry(tw, node, jail, tw_death_node)
 178
 179 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
 180         hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
 181
 182 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 183 {
 184         return (struct inet_timewait_sock *)sk;
 185 }
 186
 187 static inline u32 inet_rcv_saddr(const struct sock *sk)
 188 {
 189         return likely(sk->sk_state != TCP_TIME_WAIT) ?
 190                 inet_sk(sk)->rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
 191 }
 192
 193 static inline void inet_twsk_put(struct inet_timewait_sock *tw)
 194 {
 195         if (atomic_dec_and_test(&tw->tw_refcnt)) {
 196 #ifdef SOCK_REFCNT_DEBUG
 197                 printk(KERN_DEBUG "%s timewait_sock %p released\n",
 198                        tw->tw_prot->name, tw);
 199 #endif
 200                 kmem_cache_free(tw->tw_prot->twsk_slab, tw);
 201         }
 202 }
 203
 204 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 205                                                   const int state);
 206
 207 extern void __inet_twsk_kill(struct inet_timewait_sock *tw,
 208                              struct inet_hashinfo *hashinfo);
 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 #endif  /* _INET_TIMEWAIT_SOCK_ */