LXR linux/include/net/inet_timewait

   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/list.h>
  20#include <linux/module.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 <asm/atomic.h>
  31
  32struct 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
  66struct 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
  86extern void inet_twdr_hangman(unsigned long data);
  87extern void inet_twdr_twkill_work(struct work_struct *work);
  88extern void inet_twdr_twcal_tick(unsigned long data);
  89
  90#if (BITS_PER_LONG == 64)
  91#define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8
  92#else
  93#define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 4
  94#endif
  95
  96struct inet_bind_bucket;
  97
  98/*
  99 * This is a TIME_WAIT sock. It works around the memory consumption
 100 * problems of sockets in such a state on heavily loaded servers, but
 101 * without violating the protocol specification.
 102 */
 103struct inet_timewait_sock {
 104        /*
 105         * Now struct sock also uses sock_common, so please just
 106         * don't add nothing before this first member (__tw_common) --acme
 107         */
 108        struct sock_common      __tw_common;
 109#define tw_family               __tw_common.skc_family
 110#define tw_state                __tw_common.skc_state
 111#define tw_reuse                __tw_common.skc_reuse
 112#define tw_bound_dev_if         __tw_common.skc_bound_dev_if
 113#define tw_node                 __tw_common.skc_node
 114#define tw_bind_node            __tw_common.skc_bind_node
 115#define tw_refcnt               __tw_common.skc_refcnt
 116#define tw_hash                 __tw_common.skc_hash
 117#define tw_prot                 __tw_common.skc_prot
 118#define tw_net                  __tw_common.skc_net
 119        int                     tw_timeout;
 120        volatile unsigned char  tw_substate;
 121        /* 3 bits hole, try to pack */
 122        unsigned char           tw_rcv_wscale;
 123        /* Socket demultiplex comparisons on incoming packets. */
 124        /* these five are in inet_sock */
 125        __be16                  tw_sport;
 126        __be32                  tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
 127        __be32                  tw_rcv_saddr;
 128        __be16                  tw_dport;
 129        __u16                   tw_num;
 130        /* And these are ours. */
 131        __u8                    tw_ipv6only:1;
 132        /* 15 bits hole, try to pack */
 133        __u16                   tw_ipv6_offset;
 134        unsigned long           tw_ttd;
 135        struct inet_bind_bucket *tw_tb;
 136        struct hlist_node       tw_death_node;
 137};
 138
 139static inline void inet_twsk_add_node(struct inet_timewait_sock *tw,
 140                                      struct hlist_head *list)
 141{
 142        hlist_add_head(&tw->tw_node, list);
 143}
 144
 145static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
 146                                           struct hlist_head *list)
 147{
 148        hlist_add_head(&tw->tw_bind_node, list);
 149}
 150
 151static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 152{
 153        return !hlist_unhashed(&tw->tw_death_node);
 154}
 155
 156static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 157{
 158        tw->tw_death_node.pprev = NULL;
 159}
 160
 161static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 162{
 163        __hlist_del(&tw->tw_death_node);
 164        inet_twsk_dead_node_init(tw);
 165}
 166
 167static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 168{
 169        if (inet_twsk_dead_hashed(tw)) {
 170                __inet_twsk_del_dead_node(tw);
 171                return 1;
 172        }
 173        return 0;
 174}
 175
 176#define inet_twsk_for_each(tw, node, head) \
 177        hlist_for_each_entry(tw, node, head, tw_node)
 178
 179#define inet_twsk_for_each_inmate(tw, node, jail) \
 180        hlist_for_each_entry(tw, node, jail, tw_death_node)
 181
 182#define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
 183        hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
 184
 185static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 186{
 187        return (struct inet_timewait_sock *)sk;
 188}
 189
 190static inline __be32 inet_rcv_saddr(const struct sock *sk)
 191{
 192        return likely(sk->sk_state != TCP_TIME_WAIT) ?
 193                inet_sk(sk)->rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
 194}
 195
 196extern void inet_twsk_put(struct inet_timewait_sock *tw);
 197
 198extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 199                                                  const int state);
 200
 201extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
 202                                  struct sock *sk,
 203                                  struct inet_hashinfo *hashinfo);
 204
 205extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
 206                               struct inet_timewait_death_row *twdr,
 207                               const int timeo, const int timewait_len);
 208extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 209                                 struct inet_timewait_death_row *twdr);
 210#endif  /* _INET_TIMEWAIT_SOCK_ */
 211