net/ipv6/inet6_hashtables.c

   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  *              Generic INET6 transport hashtables
   7  *
   8  * Authors:     Lotsa people, from code originally in tcp, generalised here
   9  *              by Arnaldo Carvalho de Melo <acme@mandriva.com>
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <linux/config.h>
  18 #include <linux/module.h>
  19 #include <linux/random.h>
  20
  21 #include <net/inet_connection_sock.h>
  22 #include <net/inet_hashtables.h>
  23 #include <net/inet6_hashtables.h>
  24 #include <net/ip.h>
  25
  26 void __inet6_hash(struct inet_hashinfo *hashinfo,
  27                                 struct sock *sk)
  28 {
  29         struct hlist_head *list;
  30         rwlock_t *lock;
  31
  32         BUG_TRAP(sk_unhashed(sk));
  33
  34         if (sk->sk_state == TCP_LISTEN) {
  35                 list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
  36                 lock = &hashinfo->lhash_lock;
  37                 inet_listen_wlock(hashinfo);
  38         } else {
  39                 unsigned int hash;
  40                 sk->sk_hash = hash = inet6_sk_ehashfn(sk);
  41                 hash &= (hashinfo->ehash_size - 1);
  42                 list = &hashinfo->ehash[hash].chain;
  43                 lock = &hashinfo->ehash[hash].lock;
  44                 write_lock(lock);
  45         }
  46
  47         __sk_add_node(sk, list);
  48         sock_prot_inc_use(sk->sk_prot);
  49         write_unlock(lock);
  50 }
  51 EXPORT_SYMBOL(__inet6_hash);
  52
  53 /*
  54  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  55  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  56  *
  57  * The sockhash lock must be held as a reader here.
  58  */
  59 struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo,
  60                                            const struct in6_addr *saddr,
  61                                            const u16 sport,
  62                                            const struct in6_addr *daddr,
  63                                            const u16 hnum,
  64                                            const int dif)
  65 {
  66         struct sock *sk;
  67         const struct hlist_node *node;
  68         const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
  69         /* Optimize here for direct hit, only listening connections can
  70          * have wildcards anyways.
  71          */
  72         unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport);
  73         struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
  74
  75         prefetch(head->chain.first);
  76         read_lock(&head->lock);
  77         sk_for_each(sk, node, &head->chain) {
  78                 /* For IPV6 do the cheaper port and family tests first. */
  79                 if (INET6_MATCH(sk, hash, saddr, daddr, ports, dif))
  80                         goto hit; /* You sunk my battleship! */
  81         }
  82         /* Must check for a TIME_WAIT'er before going to listener hash. */
  83         sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) {
  84                 const struct inet_timewait_sock *tw = inet_twsk(sk);
  85
  86                 if(*((__u32 *)&(tw->tw_dport))  == ports        &&
  87                    sk->sk_family                == PF_INET6) {
  88                         const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
  89
  90                         if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)   &&
  91                             ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr)       &&
  92                             (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif))
  93                                 goto hit;
  94                 }
  95         }
  96         read_unlock(&head->lock);
  97         return NULL;
  98
  99 hit:
 100         sock_hold(sk);
 101         read_unlock(&head->lock);
 102         return sk;
 103 }
 104 EXPORT_SYMBOL(__inet6_lookup_established);
 105
 106 struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
 107                                    const struct in6_addr *daddr,
 108                                    const unsigned short hnum, const int dif)
 109 {
 110         struct sock *sk;
 111         const struct hlist_node *node;
 112         struct sock *result = NULL;
 113         int score, hiscore = 0;
 114
 115         read_lock(&hashinfo->lhash_lock);
 116         sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
 117                 if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) {
 118                         const struct ipv6_pinfo *np = inet6_sk(sk);
 119
 120                         score = 1;
 121                         if (!ipv6_addr_any(&np->rcv_saddr)) {
 122                                 if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
 123                                         continue;
 124                                 score++;
 125                         }
 126                         if (sk->sk_bound_dev_if) {
 127                                 if (sk->sk_bound_dev_if != dif)
 128                                         continue;
 129                                 score++;
 130                         }
 131                         if (score == 3) {
 132                                 result = sk;
 133                                 break;
 134                         }
 135                         if (score > hiscore) {
 136                                 hiscore = score;
 137                                 result = sk;
 138                         }
 139                 }
 140         }
 141         if (result)
 142                 sock_hold(result);
 143         read_unlock(&hashinfo->lhash_lock);
 144         return result;
 145 }
 146
 147 EXPORT_SYMBOL_GPL(inet6_lookup_listener);
 148
 149 struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
 150                           const struct in6_addr *saddr, const u16 sport,
 151                           const struct in6_addr *daddr, const u16 dport,
 152                           const int dif)
 153 {
 154         struct sock *sk;
 155
 156         local_bh_disable();
 157         sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
 158         local_bh_enable();
 159
 160         return sk;
 161 }
 162
 163 EXPORT_SYMBOL_GPL(inet6_lookup);
 164
 165 static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 166                                      struct sock *sk, const __u16 lport,
 167                                      struct inet_timewait_sock **twp)
 168 {
 169         struct inet_hashinfo *hinfo = death_row->hashinfo;
 170         struct inet_sock *inet = inet_sk(sk);
 171         const struct ipv6_pinfo *np = inet6_sk(sk);
 172         const struct in6_addr *daddr = &np->rcv_saddr;
 173         const struct in6_addr *saddr = &np->daddr;
 174         const int dif = sk->sk_bound_dev_if;
 175         const u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
 176         const unsigned int hash = inet6_ehashfn(daddr, inet->num, saddr,
 177                                                 inet->dport);
 178         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 179         struct sock *sk2;
 180         const struct hlist_node *node;
 181         struct inet_timewait_sock *tw;
 182
 183         prefetch(head->chain.first);
 184         write_lock(&head->lock);
 185
 186         /* Check TIME-WAIT sockets first. */
 187         sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) {
 188                 const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2);
 189
 190                 tw = inet_twsk(sk2);
 191
 192                 if(*((__u32 *)&(tw->tw_dport)) == ports          &&
 193                    sk2->sk_family              == PF_INET6       &&
 194                    ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)     &&
 195                    ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) &&
 196                    sk2->sk_bound_dev_if == sk->sk_bound_dev_if) {
 197                         if (twsk_unique(sk, sk2, twp))
 198                                 goto unique;
 199                         else
 200                                 goto not_unique;
 201                 }
 202         }
 203         tw = NULL;
 204
 205         /* And established part... */
 206         sk_for_each(sk2, node, &head->chain) {
 207                 if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif))
 208                         goto not_unique;
 209         }
 210
 211 unique:
 212         /* Must record num and sport now. Otherwise we will see
 213          * in hash table socket with a funny identity. */
 214         inet->num = lport;
 215         inet->sport = htons(lport);
 216         BUG_TRAP(sk_unhashed(sk));
 217         __sk_add_node(sk, &head->chain);
 218         sk->sk_hash = hash;
 219         sock_prot_inc_use(sk->sk_prot);
 220         write_unlock(&head->lock);
 221
 222         if (twp != NULL) {
 223                 *twp = tw;
 224                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 225         } else if (tw != NULL) {
 226                 /* Silly. Should hash-dance instead... */
 227                 inet_twsk_deschedule(tw, death_row);
 228                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 229
 230                 inet_twsk_put(tw);
 231         }
 232         return 0;
 233
 234 not_unique:
 235         write_unlock(&head->lock);
 236         return -EADDRNOTAVAIL;
 237 }
 238
 239 static inline u32 inet6_sk_port_offset(const struct sock *sk)
 240 {
 241         const struct inet_sock *inet = inet_sk(sk);
 242         const struct ipv6_pinfo *np = inet6_sk(sk);
 243         return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
 244                                           np->daddr.s6_addr32,
 245                                           inet->dport);
 246 }
 247
 248 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 249                        struct sock *sk)
 250 {
 251         struct inet_hashinfo *hinfo = death_row->hashinfo;
 252         const unsigned short snum = inet_sk(sk)->num;
 253         struct inet_bind_hashbucket *head;
 254         struct inet_bind_bucket *tb;
 255         int ret;
 256
 257         if (snum == 0) {
 258                 const int low = sysctl_local_port_range[0];
 259                 const int high = sysctl_local_port_range[1];
 260                 const int range = high - low;
 261                 int i, port;
 262                 static u32 hint;
 263                 const u32 offset = hint + inet6_sk_port_offset(sk);
 264                 struct hlist_node *node;
 265                 struct inet_timewait_sock *tw = NULL;
 266
 267                 local_bh_disable();
 268                 for (i = 1; i <= range; i++) {
 269                         port = low + (i + offset) % range;
 270                         head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
 271                         spin_lock(&head->lock);
 272
 273                         /* Does not bother with rcv_saddr checks,
 274                          * because the established check is already
 275                          * unique enough.
 276                          */
 277                         inet_bind_bucket_for_each(tb, node, &head->chain) {
 278                                 if (tb->port == port) {
 279                                         BUG_TRAP(!hlist_empty(&tb->owners));
 280                                         if (tb->fastreuse >= 0)
 281                                                 goto next_port;
 282                                         if (!__inet6_check_established(death_row,
 283                                                                        sk, port,
 284                                                                        &tw))
 285                                                 goto ok;
 286                                         goto next_port;
 287                                 }
 288                         }
 289
 290                         tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
 291                                                      head, port);
 292                         if (!tb) {
 293                                 spin_unlock(&head->lock);
 294                                 break;
 295                         }
 296                         tb->fastreuse = -1;
 297                         goto ok;
 298
 299                 next_port:
 300                         spin_unlock(&head->lock);
 301                 }
 302                 local_bh_enable();
 303
 304                 return -EADDRNOTAVAIL;
 305
 306 ok:
 307                 hint += i;
 308
 309                 /* Head lock still held and bh's disabled */
 310                 inet_bind_hash(sk, tb, port);
 311                 if (sk_unhashed(sk)) {
 312                         inet_sk(sk)->sport = htons(port);
 313                         __inet6_hash(hinfo, sk);
 314                 }
 315                 spin_unlock(&head->lock);
 316
 317                 if (tw) {
 318                         inet_twsk_deschedule(tw, death_row);
 319                         inet_twsk_put(tw);
 320                 }
 321
 322                 ret = 0;
 323                 goto out;
 324         }
 325
 326         head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
 327         tb   = inet_csk(sk)->icsk_bind_hash;
 328         spin_lock_bh(&head->lock);
 329
 330         if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
 331                 __inet6_hash(hinfo, sk);
 332                 spin_unlock_bh(&head->lock);
 333                 return 0;
 334         } else {
 335                 spin_unlock(&head->lock);
 336                 /* No definite answer... Walk to established hash table */
 337                 ret = __inet6_check_established(death_row, sk, snum, NULL);
 338 out:
 339                 local_bh_enable();
 340                 return ret;
 341         }
 342 }
 343
 344 EXPORT_SYMBOL_GPL(inet6_hash_connect);