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
  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
  32 struct 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
  66 struct 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
  86 extern void inet_twdr_hangman(unsigned long data);
  87 extern void inet_twdr_twkill_work(struct work_struct *work);
  88 extern 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
  96 struct 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  */
 103 struct 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         volatile unsigned char  tw_substate;
 120         /* 3 bits hole, try to pack */
 121         unsigned char           tw_rcv_wscale;
 122         /* Socket demultiplex comparisons on incoming packets. */
 123         /* these five are in inet_sock */
 124         __be16                  tw_sport;
 125         __be32                  tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
 126         __be32                  tw_rcv_saddr;
 127         __be16                  tw_dport;
 128         __u16                   tw_num;
 129         /* And these are ours. */
 130         __u8                    tw_ipv6only:1;
 131         /* 15 bits hole, try to pack */
 132         __u16                   tw_ipv6_offset;
 133         int                     tw_timeout;
 134         unsigned long           tw_ttd;
 135         struct inet_bind_bucket *tw_tb;
 136         struct hlist_node       tw_death_node;
 137 };
 138
 139 static 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
 145 static 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
 151 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 152 {
 153         return !hlist_unhashed(&tw->tw_death_node);
 154 }
 155
 156 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 157 {
 158         tw->tw_death_node.pprev = NULL;
 159 }
 160
 161 static 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
 167 static 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
 185 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 186 {
 187         return (struct inet_timewait_sock *)sk;
 188 }
 189
 190 static 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
 196 static inline void inet_twsk_put(struct inet_timewait_sock *tw)
 197 {
 198         if (atomic_dec_and_test(&tw->tw_refcnt)) {
 199                 struct module *owner = tw->tw_prot->owner;
 200                 twsk_destructor((struct sock *)tw);
 201 #ifdef SOCK_REFCNT_DEBUG
 202                 printk(KERN_DEBUG "%s timewait_sock %p released\n",
 203                        tw->tw_prot->name, tw);
 204 #endif
 205                 kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw);
 206                 module_put(owner);
 207         }
 208 }
 209
 210 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 211                                                   const int state);
 212
 213 extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
 214                                   struct sock *sk,
 215                                   struct inet_hashinfo *hashinfo);
 216
 217 extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
 218                                struct inet_timewait_death_row *twdr,
 219                                const int timeo, const int timewait_len);
 220 extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 221                                  struct inet_timewait_death_row *twdr);
 222 #endif  /* _INET_TIMEWAIT_SOCK_ */