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/module.h>
  18 #include <linux/random.h>
  19
  20 #include <net/inet_connection_sock.h>
  21 #include <net/inet_hashtables.h>
  22 #include <net/inet6_hashtables.h>
  23 #include <net/ip.h>
  24
  25 void __inet6_hash(struct sock *sk)
  26 {
  27         struct inet_hashinfo *hashinfo = sk->sk_prot->hashinfo;
  28         struct hlist_head *list;
  29         rwlock_t *lock;
  30
  31         BUG_TRAP(sk_unhashed(sk));
  32
  33         if (sk->sk_state == TCP_LISTEN) {
  34                 list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
  35                 lock = &hashinfo->lhash_lock;
  36                 inet_listen_wlock(hashinfo);
  37         } else {
  38                 unsigned int hash;
  39                 sk->sk_hash = hash = inet6_sk_ehashfn(sk);
  40                 list = &inet_ehash_bucket(hashinfo, hash)->chain;
  41                 lock = inet_ehash_lockp(hashinfo, hash);
  42                 write_lock(lock);
  43         }
  44
  45         __sk_add_node(sk, list);
  46         sock_prot_inuse_add(sk->sk_prot, 1);
  47         write_unlock(lock);
  48 }
  49 EXPORT_SYMBOL(__inet6_hash);
  50
  51 /*
  52  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  53  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  54  *
  55  * The sockhash lock must be held as a reader here.
  56  */
  57 struct sock *__inet6_lookup_established(struct net *net,
  58                                         struct inet_hashinfo *hashinfo,
  59                                            const struct in6_addr *saddr,
  60                                            const __be16 sport,
  61                                            const struct in6_addr *daddr,
  62                                            const u16 hnum,
  63                                            const int dif)
  64 {
  65         struct sock *sk;
  66         const struct hlist_node *node;
  67         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
  68         /* Optimize here for direct hit, only listening connections can
  69          * have wildcards anyways.
  70          */
  71         unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport);
  72         struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
  73         rwlock_t *lock = inet_ehash_lockp(hashinfo, hash);
  74
  75         prefetch(head->chain.first);
  76         read_lock(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, net, 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->twchain) {
  84                 if (INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif))
  85                         goto hit;
  86         }
  87         read_unlock(lock);
  88         return NULL;
  89
  90 hit:
  91         sock_hold(sk);
  92         read_unlock(lock);
  93         return sk;
  94 }
  95 EXPORT_SYMBOL(__inet6_lookup_established);
  96
  97 struct sock *inet6_lookup_listener(struct net *net,
  98                 struct inet_hashinfo *hashinfo, const struct in6_addr *daddr,
  99                 const unsigned short hnum, const int dif)
 100 {
 101         struct sock *sk;
 102         const struct hlist_node *node;
 103         struct sock *result = NULL;
 104         int score, hiscore = 0;
 105
 106         read_lock(&hashinfo->lhash_lock);
 107         sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
 108                 if (sk->sk_net == net && inet_sk(sk)->num == hnum &&
 109                                 sk->sk_family == PF_INET6) {
 110                         const struct ipv6_pinfo *np = inet6_sk(sk);
 111
 112                         score = 1;
 113                         if (!ipv6_addr_any(&np->rcv_saddr)) {
 114                                 if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
 115                                         continue;
 116                                 score++;
 117                         }
 118                         if (sk->sk_bound_dev_if) {
 119                                 if (sk->sk_bound_dev_if != dif)
 120                                         continue;
 121                                 score++;
 122                         }
 123                         if (score == 3) {
 124                                 result = sk;
 125                                 break;
 126                         }
 127                         if (score > hiscore) {
 128                                 hiscore = score;
 129                                 result = sk;
 130                         }
 131                 }
 132         }
 133         if (result)
 134                 sock_hold(result);
 135         read_unlock(&hashinfo->lhash_lock);
 136         return result;
 137 }
 138
 139 EXPORT_SYMBOL_GPL(inet6_lookup_listener);
 140
 141 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
 142                           const struct in6_addr *saddr, const __be16 sport,
 143                           const struct in6_addr *daddr, const __be16 dport,
 144                           const int dif)
 145 {
 146         struct sock *sk;
 147
 148         local_bh_disable();
 149         sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif);
 150         local_bh_enable();
 151
 152         return sk;
 153 }
 154
 155 EXPORT_SYMBOL_GPL(inet6_lookup);
 156
 157 static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 158                                      struct sock *sk, const __u16 lport,
 159                                      struct inet_timewait_sock **twp)
 160 {
 161         struct inet_hashinfo *hinfo = death_row->hashinfo;
 162         struct inet_sock *inet = inet_sk(sk);
 163         const struct ipv6_pinfo *np = inet6_sk(sk);
 164         const struct in6_addr *daddr = &np->rcv_saddr;
 165         const struct in6_addr *saddr = &np->daddr;
 166         const int dif = sk->sk_bound_dev_if;
 167         const __portpair ports = INET_COMBINED_PORTS(inet->dport, lport);
 168         const unsigned int hash = inet6_ehashfn(daddr, lport, saddr,
 169                                                 inet->dport);
 170         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 171         rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
 172         struct sock *sk2;
 173         const struct hlist_node *node;
 174         struct inet_timewait_sock *tw;
 175         struct net *net = sk->sk_net;
 176
 177         prefetch(head->chain.first);
 178         write_lock(lock);
 179
 180         /* Check TIME-WAIT sockets first. */
 181         sk_for_each(sk2, node, &head->twchain) {
 182                 tw = inet_twsk(sk2);
 183
 184                 if (INET6_TW_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) {
 185                         if (twsk_unique(sk, sk2, twp))
 186                                 goto unique;
 187                         else
 188                                 goto not_unique;
 189                 }
 190         }
 191         tw = NULL;
 192
 193         /* And established part... */
 194         sk_for_each(sk2, node, &head->chain) {
 195                 if (INET6_MATCH(sk2, net, hash, saddr, daddr, ports, dif))
 196                         goto not_unique;
 197         }
 198
 199 unique:
 200         /* Must record num and sport now. Otherwise we will see
 201          * in hash table socket with a funny identity. */
 202         inet->num = lport;
 203         inet->sport = htons(lport);
 204         BUG_TRAP(sk_unhashed(sk));
 205         __sk_add_node(sk, &head->chain);
 206         sk->sk_hash = hash;
 207         sock_prot_inuse_add(sk->sk_prot, 1);
 208         write_unlock(lock);
 209
 210         if (twp != NULL) {
 211                 *twp = tw;
 212                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 213         } else if (tw != NULL) {
 214                 /* Silly. Should hash-dance instead... */
 215                 inet_twsk_deschedule(tw, death_row);
 216                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 217
 218                 inet_twsk_put(tw);
 219         }
 220         return 0;
 221
 222 not_unique:
 223         write_unlock(lock);
 224         return -EADDRNOTAVAIL;
 225 }
 226
 227 static inline u32 inet6_sk_port_offset(const struct sock *sk)
 228 {
 229         const struct inet_sock *inet = inet_sk(sk);
 230         const struct ipv6_pinfo *np = inet6_sk(sk);
 231         return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
 232                                           np->daddr.s6_addr32,
 233                                           inet->dport);
 234 }
 235
 236 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 237                        struct sock *sk)
 238 {
 239         return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk),
 240                         __inet6_check_established, __inet6_hash);
 241 }
 242
 243 EXPORT_SYMBOL_GPL(inet6_hash_connect);