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/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
  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 static 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
  71 struct 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
  91 void inet_twdr_hangman(unsigned long data);
  92 void inet_twdr_twkill_work(struct work_struct *work);
  93 void inet_twdr_twcal_tick(unsigned long data);
  94
  95 struct 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  */
 102 struct 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_bound_dev_if         __tw_common.skc_bound_dev_if
 112 #define tw_node                 __tw_common.skc_nulls_node
 113 #define tw_bind_node            __tw_common.skc_bind_node
 114 #define tw_refcnt               __tw_common.skc_refcnt
 115 #define tw_hash                 __tw_common.skc_hash
 116 #define tw_prot                 __tw_common.skc_prot
 117 #define tw_net                  __tw_common.skc_net
 118 #define tw_daddr                __tw_common.skc_daddr
 119 #define tw_rcv_saddr            __tw_common.skc_rcv_saddr
 120 #define tw_dport                __tw_common.skc_dport
 121 #define tw_num                  __tw_common.skc_num
 122
 123         int                     tw_timeout;
 124         volatile unsigned char  tw_substate;
 125         unsigned char           tw_rcv_wscale;
 126
 127         /* Socket demultiplex comparisons on incoming packets. */
 128         /* these three are in inet_sock */
 129         __be16                  tw_sport;
 130         kmemcheck_bitfield_begin(flags);
 131         /* And these are ours. */
 132         unsigned int            tw_ipv6only     : 1,
 133                                 tw_transparent  : 1,
 134                                 tw_pad          : 6,    /* 6 bits hole */
 135                                 tw_tos          : 8,
 136                                 tw_ipv6_offset  : 16;
 137         kmemcheck_bitfield_end(flags);
 138         u32                     tw_ttd;
 139         struct inet_bind_bucket *tw_tb;
 140         struct hlist_node       tw_death_node;
 141 };
 142 #define tw_tclass tw_tos
 143
 144 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 145 {
 146         return !hlist_unhashed(&tw->tw_death_node);
 147 }
 148
 149 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
 150 {
 151         tw->tw_death_node.pprev = NULL;
 152 }
 153
 154 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 155 {
 156         __hlist_del(&tw->tw_death_node);
 157         inet_twsk_dead_node_init(tw);
 158 }
 159
 160 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 161 {
 162         if (inet_twsk_dead_hashed(tw)) {
 163                 __inet_twsk_del_dead_node(tw);
 164                 return 1;
 165         }
 166         return 0;
 167 }
 168
 169 #define inet_twsk_for_each(tw, node, head) \
 170         hlist_nulls_for_each_entry(tw, node, head, tw_node)
 171
 172 #define inet_twsk_for_each_inmate(tw, jail) \
 173         hlist_for_each_entry(tw, jail, tw_death_node)
 174
 175 #define inet_twsk_for_each_inmate_safe(tw, safe, jail) \
 176         hlist_for_each_entry_safe(tw, safe, jail, tw_death_node)
 177
 178 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 179 {
 180         return (struct inet_timewait_sock *)sk;
 181 }
 182
 183 void inet_twsk_free(struct inet_timewait_sock *tw);
 184 void inet_twsk_put(struct inet_timewait_sock *tw);
 185
 186 int inet_twsk_unhash(struct inet_timewait_sock *tw);
 187
 188 int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
 189                           struct inet_hashinfo *hashinfo);
 190
 191 struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 192                                            const int state);
 193
 194 void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 195                            struct inet_hashinfo *hashinfo);
 196
 197 void inet_twsk_schedule(struct inet_timewait_sock *tw,
 198                         struct inet_timewait_death_row *twdr,
 199                         const int timeo, const int timewait_len);
 200 void inet_twsk_deschedule(struct inet_timewait_sock *tw,
 201                           struct inet_timewait_death_row *twdr);
 202
 203 void inet_twsk_purge(struct inet_hashinfo *hashinfo,
 204                      struct inet_timewait_death_row *twdr, int family);
 205
 206 static inline
 207 struct net *twsk_net(const struct inet_timewait_sock *twsk)
 208 {
 209         return read_pnet(&twsk->tw_net);
 210 }
 211
 212 static inline
 213 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
 214 {
 215         write_pnet(&twsk->tw_net, net);
 216 }
 217 #endif  /* _INET_TIMEWAIT_SOCK_ */