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/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
  61static inline u32 inet_tw_time_stamp(void)
  62{
  63        return jiffies;
  64}
  65
  66/* TIME_WAIT reaping mechanism. */
  67#define INET_TWDR_TWKILL_SLOTS  8 /* Please keep this a power of 2. */
  68
  69#define INET_TWDR_TWKILL_QUOTA 100
  70
  71struct inet_timewait_death_row {
  72        /* Short-time timewait calendar */
  73        int                     twcal_hand;
  74        unsigned long           twcal_jiffie;
  75        struct timer_list       twcal_timer;
  76        struct hlist_head       twcal_row[INET_TWDR_RECYCLE_SLOTS];
  77
  78        spinlock_t              death_lock;
  79        int                     tw_count;
  80        int                     period;
  81        u32                     thread_slots;
  82        struct work_struct      twkill_work;
  83        struct timer_list       tw_timer;
  84        int                     slot;
  85        struct hlist_head       cells[INET_TWDR_TWKILL_SLOTS];
  86        struct inet_hashinfo    *hashinfo;
  87        int                     sysctl_tw_recycle;
  88        int                     sysctl_max_tw_buckets;
  89};
  90
  91void inet_twdr_hangman(unsigned long data);
  92void inet_twdr_twkill_work(struct work_struct *work);
  93void inet_twdr_twcal_tick(unsigned long data);
  94
  95struct 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 */
 102struct 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_ipv6only             __tw_common.skc_ipv6only
 112#define tw_bound_dev_if         __tw_common.skc_bound_dev_if
 113#define tw_node                 __tw_common.skc_nulls_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#define tw_daddr                __tw_common.skc_daddr
 120#define tw_v6_daddr             __tw_common.skc_v6_daddr
 121#define tw_rcv_saddr            __tw_common.skc_rcv_saddr
 122#define tw_v6_rcv_saddr         __tw_common.skc_v6_rcv_saddr
 123#define tw_dport                __tw_common.skc_dport
 124#define tw_num                  __tw_common.skc_num
 125
 126        int                     tw_timeout;
 127        volatile unsigned char  tw_substate;
 128        unsigned char           tw_rcv_wscale;
 129
 130        /* Socket demultiplex comparisons on incoming packets. */
 131        /* these three are in inet_sock */
 132        __be16                  tw_sport;
 133        kmemcheck_bitfield_begin(flags);
 134        /* And these are ours. */
 135        unsigned int            tw_pad0         : 1,    /* 1 bit hole */
 136                                tw_transparent  : 1,
 137                                tw_flowlabel    : 20,
 138                                tw_pad          : 2,    /* 2 bits hole */
 139                                tw_tos          : 8;
 140        kmemcheck_bitfield_end(flags);
 141        u32                     tw_ttd;
 142        struct inet_bind_bucket *tw_tb;
 143        struct hlist_node       tw_death_node;
 144};
 145#define tw_tclass tw_tos
 146
 147static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 148{
 149        return !hlist_unhashed(&tw->tw_death_node);
 150}
 151
 152static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 153{
 154        tw->tw_death_node.pprev = NULL;
 155}
 156
 157static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 158{
 159        __hlist_del(&tw->tw_death_node);
 160        inet_twsk_dead_node_init(tw);
 161}
 162
 163static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 164{
 165        if (inet_twsk_dead_hashed(tw)) {
 166                __inet_twsk_del_dead_node(tw);
 167                return 1;
 168        }
 169        return 0;
 170}
 171
 172#define inet_twsk_for_each(tw, node, head) \
 173        hlist_nulls_for_each_entry(tw, node, head, tw_node)
 174
 175#define inet_twsk_for_each_inmate(tw, jail) \
 176        hlist_for_each_entry(tw, jail, tw_death_node)
 177
 178#define inet_twsk_for_each_inmate_safe(tw, safe, jail) \
 179        hlist_for_each_entry_safe(tw, safe, jail, tw_death_node)
 180
 181static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 182{
 183        return (struct inet_timewait_sock *)sk;
 184}
 185
 186void inet_twsk_free(struct inet_timewait_sock *tw);
 187void inet_twsk_put(struct inet_timewait_sock *tw);
 188
 189int inet_twsk_unhash(struct inet_timewait_sock *tw);
 190
 191int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
 192                          struct inet_hashinfo *hashinfo);
 193
 194struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 195                                           const int state);
 196
 197void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 198                           struct inet_hashinfo *hashinfo);
 199
 200void inet_twsk_schedule(struct inet_timewait_sock *tw,
 201                        struct inet_timewait_death_row *twdr,
 202                        const int timeo, const int timewait_len);
 203void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 204                          struct inet_timewait_death_row *twdr);
 205
 206void inet_twsk_purge(struct inet_hashinfo *hashinfo,
 207                     struct inet_timewait_death_row *twdr, int family);
 208
 209static inline
 210struct net *twsk_net(const struct inet_timewait_sock *twsk)
 211{
 212        return read_pnet(&twsk->tw_net);
 213}
 214
 215static inline
 216void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
 217{
 218        write_pnet(&twsk->tw_net, net);
 219}
 220#endif  /* _INET_TIMEWAIT_SOCK_ */
 221