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/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 <linux/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
  90struct inet_bind_bucket;
  91
  92/*
  93 * This is a TIME_WAIT sock. It works around the memory consumption
  94 * problems of sockets in such a state on heavily loaded servers, but
  95 * without violating the protocol specification.
  96 */
  97struct inet_timewait_sock {
  98        /*
  99         * Now struct sock also uses sock_common, so please just
 100         * don't add nothing before this first member (__tw_common) --acme
 101         */
 102        struct sock_common      __tw_common;
 103#define tw_family               __tw_common.skc_family
 104#define tw_state                __tw_common.skc_state
 105#define tw_reuse                __tw_common.skc_reuse
 106#define tw_bound_dev_if         __tw_common.skc_bound_dev_if
 107#define tw_node                 __tw_common.skc_nulls_node
 108#define tw_bind_node            __tw_common.skc_bind_node
 109#define tw_refcnt               __tw_common.skc_refcnt
 110#define tw_hash                 __tw_common.skc_hash
 111#define tw_prot                 __tw_common.skc_prot
 112#define tw_net                  __tw_common.skc_net
 113#define tw_daddr                __tw_common.skc_daddr
 114#define tw_rcv_saddr            __tw_common.skc_rcv_saddr
 115        int                     tw_timeout;
 116        volatile unsigned char  tw_substate;
 117        unsigned char           tw_rcv_wscale;
 118
 119        /* Socket demultiplex comparisons on incoming packets. */
 120        /* these three are in inet_sock */
 121        __be16                  tw_sport;
 122        __be16                  tw_dport;
 123        __u16                   tw_num;
 124        kmemcheck_bitfield_begin(flags);
 125        /* And these are ours. */
 126        unsigned int            tw_ipv6only     : 1,
 127                                tw_transparent  : 1,
 128                                tw_pad          : 6,    /* 6 bits hole */
 129                                tw_tos          : 8,
 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#define tw_tclass tw_tos
 137
 138static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
 139                                      struct hlist_nulls_head *list)
 140{
 141        hlist_nulls_add_head_rcu(&tw->tw_node, list);
 142}
 143
 144static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
 145                                           struct hlist_head *list)
 146{
 147        hlist_add_head(&tw->tw_bind_node, list);
 148}
 149
 150static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 151{
 152        return !hlist_unhashed(&tw->tw_death_node);
 153}
 154
 155static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 156{
 157        tw->tw_death_node.pprev = NULL;
 158}
 159
 160static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 161{
 162        __hlist_del(&tw->tw_death_node);
 163        inet_twsk_dead_node_init(tw);
 164}
 165
 166static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 167{
 168        if (inet_twsk_dead_hashed(tw)) {
 169                __inet_twsk_del_dead_node(tw);
 170                return 1;
 171        }
 172        return 0;
 173}
 174
 175#define inet_twsk_for_each(tw, node, head) \
 176        hlist_nulls_for_each_entry(tw, node, head, tw_node)
 177
 178#define inet_twsk_for_each_inmate(tw, node, jail) \
 179        hlist_for_each_entry(tw, node, jail, tw_death_node)
 180
 181#define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
 182        hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
 183
 184static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 185{
 186        return (struct inet_timewait_sock *)sk;
 187}
 188
 189static inline __be32 sk_rcv_saddr(const struct sock *sk)
 190{
 191/* both inet_sk() and inet_twsk() store rcv_saddr in skc_rcv_saddr */
 192        return sk->__sk_common.skc_rcv_saddr;
 193}
 194
 195extern void inet_twsk_put(struct inet_timewait_sock *tw);
 196
 197extern int inet_twsk_unhash(struct inet_timewait_sock *tw);
 198
 199extern int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
 200                                 struct inet_hashinfo *hashinfo);
 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 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        return read_pnet(&twsk->tw_net);
 222}
 223
 224static inline
 225void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
 226{
 227        write_pnet(&twsk->tw_net, net);
 228}
 229#endif  /* _INET_TIMEWAIT_SOCK_ */
 230
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