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 #include <linux/config.h>
  19
  20 #include <linux/list.h>
  21 #include <linux/types.h>
  22
  23 #include <net/sock.h>
  24 #include <net/tcp_states.h>
  25
  26 #include <asm/atomic.h>
  27
  28 #if (BITS_PER_LONG == 64)
  29 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8
  30 #else
  31 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 4
  32 #endif
  33
  34 struct inet_bind_bucket;
  35
  36 /*
  37  * This is a TIME_WAIT sock. It works around the memory consumption
  38  * problems of sockets in such a state on heavily loaded servers, but
  39  * without violating the protocol specification.
  40  */
  41 struct inet_timewait_sock {
  42         /*
  43          * Now struct sock also uses sock_common, so please just
  44          * don't add nothing before this first member (__tw_common) --acme
  45          */
  46         struct sock_common      __tw_common;
  47 #define tw_family               __tw_common.skc_family
  48 #define tw_state                __tw_common.skc_state
  49 #define tw_reuse                __tw_common.skc_reuse
  50 #define tw_bound_dev_if         __tw_common.skc_bound_dev_if
  51 #define tw_node                 __tw_common.skc_node
  52 #define tw_bind_node            __tw_common.skc_bind_node
  53 #define tw_refcnt               __tw_common.skc_refcnt
  54 #define tw_prot                 __tw_common.skc_prot
  55         volatile unsigned char  tw_substate;
  56         /* 3 bits hole, try to pack */
  57         unsigned char           tw_rcv_wscale;
  58         /* Socket demultiplex comparisons on incoming packets. */
  59         /* these five are in inet_sock */
  60         __u16                   tw_sport;
  61         __u32                   tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
  62         __u32                   tw_rcv_saddr;
  63         __u16                   tw_dport;
  64         __u16                   tw_num;
  65         /* And these are ours. */
  66         __u8                    tw_ipv6only:1;
  67         /* 31 bits hole, try to pack */
  68         int                     tw_hashent;
  69         int                     tw_timeout;
  70         unsigned long           tw_ttd;
  71         struct inet_bind_bucket *tw_tb;
  72         struct hlist_node       tw_death_node;
  73 };
  74
  75 static inline void inet_twsk_add_node(struct inet_timewait_sock *tw,
  76                                       struct hlist_head *list)
  77 {
  78         hlist_add_head(&tw->tw_node, list);
  79 }
  80
  81 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
  82                                            struct hlist_head *list)
  83 {
  84         hlist_add_head(&tw->tw_bind_node, list);
  85 }
  86
  87 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
  88 {
  89         return tw->tw_death_node.pprev != NULL;
  90 }
  91
  92 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
  93 {
  94         tw->tw_death_node.pprev = NULL;
  95 }
  96
  97 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
  98 {
  99         __hlist_del(&tw->tw_death_node);
 100         inet_twsk_dead_node_init(tw);
 101 }
 102
 103 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 104 {
 105         if (inet_twsk_dead_hashed(tw)) {
 106                 __inet_twsk_del_dead_node(tw);
 107                 return 1;
 108         }
 109         return 0;
 110 }
 111
 112 #define inet_twsk_for_each(tw, node, head) \
 113         hlist_for_each_entry(tw, node, head, tw_node)
 114
 115 #define inet_twsk_for_each_inmate(tw, node, jail) \
 116         hlist_for_each_entry(tw, node, jail, tw_death_node)
 117
 118 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
 119         hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
 120
 121 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 122 {
 123         return (struct inet_timewait_sock *)sk;
 124 }
 125
 126 static inline u32 inet_rcv_saddr(const struct sock *sk)
 127 {
 128         return likely(sk->sk_state != TCP_TIME_WAIT) ?
 129                 inet_sk(sk)->rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
 130 }
 131
 132 static inline void inet_twsk_put(struct inet_timewait_sock *tw)
 133 {
 134         if (atomic_dec_and_test(&tw->tw_refcnt)) {
 135 #ifdef SOCK_REFCNT_DEBUG
 136                 printk(KERN_DEBUG "%s timewait_sock %p released\n",
 137                        tw->tw_prot->name, tw);
 138 #endif
 139                 kmem_cache_free(tw->tw_prot->twsk_slab, tw);
 140         }
 141 }
 142 #endif  /* _INET_TIMEWAIT_SOCK_ */