linux/include/net/inet_timewait_sock.h
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   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
  33struct 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
  67struct 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
  87extern void inet_twdr_hangman(unsigned long data);
  88extern void inet_twdr_twkill_work(struct work_struct *work);
  89extern 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
  97struct 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 */
 104struct 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
 143static 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
 149static 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
 155static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 156{
 157        return !hlist_unhashed(&tw->tw_death_node);
 158}
 159
 160static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 161{
 162        tw->tw_death_node.pprev = NULL;
 163}
 164
 165static 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
 171static 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
 189static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 190{
 191        return (struct inet_timewait_sock *)sk;
 192}
 193
 194static inline __be32 inet_rcv_saddr(const struct sock *sk)
 195{
 196        return likely(sk->sk_state != TCP_TIME_WAIT) ?
 197                inet_sk(sk)->rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
 198}
 199
 200extern void inet_twsk_put(struct inet_timewait_sock *tw);
 201
 202extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 203                                                  const int state);
 204
 205extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
 206                                  struct sock *sk,
 207                                  struct inet_hashinfo *hashinfo);
 208
 209extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
 210                               struct inet_timewait_death_row *twdr,
 211                               const int timeo, const int timewait_len);
 212extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 213                                 struct inet_timewait_death_row *twdr);
 214
 215extern void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
 216                            struct inet_timewait_death_row *twdr, int family);
 217
 218static inline
 219struct net *twsk_net(const struct inet_timewait_sock *twsk)
 220{
 221#ifdef CONFIG_NET_NS
 222        return twsk->tw_net;
 223#else
 224        return &init_net;
 225#endif
 226}
 227
 228static inline
 229void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
 230{
 231#ifdef CONFIG_NET_NS
 232        twsk->tw_net = net;
 233#endif
 234}
 235#endif  /* _INET_TIMEWAIT_SOCK_ */
 236
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