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/addrconf.h>
  21 #include <net/inet_connection_sock.h>
  22 #include <net/inet_hashtables.h>
  23 #include <net/inet6_hashtables.h>
  24 #include <net/secure_seq.h>
  25 #include <net/ip.h>
  26 #include <net/sock_reuseport.h>
  27
  28 u32 inet6_ehashfn(const struct net *net,
  29                   const struct in6_addr *laddr, const u16 lport,
  30                   const struct in6_addr *faddr, const __be16 fport)
  31 {
  32         static u32 inet6_ehash_secret __read_mostly;
  33         static u32 ipv6_hash_secret __read_mostly;
  34
  35         u32 lhash, fhash;
  36
  37         net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
  38         net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
  39
  40         lhash = (__force u32)laddr->s6_addr32[3];
  41         fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
  42
  43         return __inet6_ehashfn(lhash, lport, fhash, fport,
  44                                inet6_ehash_secret + net_hash_mix(net));
  45 }
  46
  47 /*
  48  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  49  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  50  *
  51  * The sockhash lock must be held as a reader here.
  52  */
  53 struct sock *__inet6_lookup_established(struct net *net,
  54                                         struct inet_hashinfo *hashinfo,
  55                                            const struct in6_addr *saddr,
  56                                            const __be16 sport,
  57                                            const struct in6_addr *daddr,
  58                                            const u16 hnum,
  59                                            const int dif)
  60 {
  61         struct sock *sk;
  62         const struct hlist_nulls_node *node;
  63         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
  64         /* Optimize here for direct hit, only listening connections can
  65          * have wildcards anyways.
  66          */
  67         unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
  68         unsigned int slot = hash & hashinfo->ehash_mask;
  69         struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
  70
  71
  72         rcu_read_lock();
  73 begin:
  74         sk_nulls_for_each_rcu(sk, node, &head->chain) {
  75                 if (sk->sk_hash != hash)
  76                         continue;
  77                 if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif))
  78                         continue;
  79                 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
  80                         goto out;
  81
  82                 if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif))) {
  83                         sock_gen_put(sk);
  84                         goto begin;
  85                 }
  86                 goto found;
  87         }
  88         if (get_nulls_value(node) != slot)
  89                 goto begin;
  90 out:
  91         sk = NULL;
  92 found:
  93         rcu_read_unlock();
  94         return sk;
  95 }
  96 EXPORT_SYMBOL(__inet6_lookup_established);
  97
  98 static inline int compute_score(struct sock *sk, struct net *net,
  99                                 const unsigned short hnum,
 100                                 const struct in6_addr *daddr,
 101                                 const int dif)
 102 {
 103         int score = -1;
 104
 105         if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
 106             sk->sk_family == PF_INET6) {
 107
 108                 score = 1;
 109                 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
 110                         if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 111                                 return -1;
 112                         score++;
 113                 }
 114                 if (sk->sk_bound_dev_if) {
 115                         if (sk->sk_bound_dev_if != dif)
 116                                 return -1;
 117                         score++;
 118                 }
 119                 if (sk->sk_incoming_cpu == raw_smp_processor_id())
 120                         score++;
 121         }
 122         return score;
 123 }
 124
 125 struct sock *inet6_lookup_listener(struct net *net,
 126                 struct inet_hashinfo *hashinfo,
 127                 struct sk_buff *skb, int doff,
 128                 const struct in6_addr *saddr,
 129                 const __be16 sport, const struct in6_addr *daddr,
 130                 const unsigned short hnum, const int dif)
 131 {
 132         struct sock *sk;
 133         const struct hlist_nulls_node *node;
 134         struct sock *result;
 135         int score, hiscore, matches = 0, reuseport = 0;
 136         bool select_ok = true;
 137         u32 phash = 0;
 138         unsigned int hash = inet_lhashfn(net, hnum);
 139         struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
 140
 141         rcu_read_lock();
 142 begin:
 143         result = NULL;
 144         hiscore = 0;
 145         sk_nulls_for_each(sk, node, &ilb->head) {
 146                 score = compute_score(sk, net, hnum, daddr, dif);
 147                 if (score > hiscore) {
 148                         hiscore = score;
 149                         result = sk;
 150                         reuseport = sk->sk_reuseport;
 151                         if (reuseport) {
 152                                 phash = inet6_ehashfn(net, daddr, hnum,
 153                                                       saddr, sport);
 154                                 if (select_ok) {
 155                                         struct sock *sk2;
 156                                         sk2 = reuseport_select_sock(sk, phash,
 157                                                                     skb, doff);
 158                                         if (sk2) {
 159                                                 result = sk2;
 160                                                 goto found;
 161                                         }
 162                                 }
 163                                 matches = 1;
 164                         }
 165                 } else if (score == hiscore && reuseport) {
 166                         matches++;
 167                         if (reciprocal_scale(phash, matches) == 0)
 168                                 result = sk;
 169                         phash = next_pseudo_random32(phash);
 170                 }
 171         }
 172         /*
 173          * if the nulls value we got at the end of this lookup is
 174          * not the expected one, we must restart lookup.
 175          * We probably met an item that was moved to another chain.
 176          */
 177         if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
 178                 goto begin;
 179         if (result) {
 180 found:
 181                 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
 182                         result = NULL;
 183                 else if (unlikely(compute_score(result, net, hnum, daddr,
 184                                   dif) < hiscore)) {
 185                         sock_put(result);
 186                         select_ok = false;
 187                         goto begin;
 188                 }
 189         }
 190         rcu_read_unlock();
 191         return result;
 192 }
 193 EXPORT_SYMBOL_GPL(inet6_lookup_listener);
 194
 195 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
 196                           struct sk_buff *skb, int doff,
 197                           const struct in6_addr *saddr, const __be16 sport,
 198                           const struct in6_addr *daddr, const __be16 dport,
 199                           const int dif)
 200 {
 201         struct sock *sk;
 202
 203         local_bh_disable();
 204         sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
 205                             ntohs(dport), dif);
 206         local_bh_enable();
 207
 208         return sk;
 209 }
 210 EXPORT_SYMBOL_GPL(inet6_lookup);
 211
 212 static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 213                                      struct sock *sk, const __u16 lport,
 214                                      struct inet_timewait_sock **twp)
 215 {
 216         struct inet_hashinfo *hinfo = death_row->hashinfo;
 217         struct inet_sock *inet = inet_sk(sk);
 218         const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr;
 219         const struct in6_addr *saddr = &sk->sk_v6_daddr;
 220         const int dif = sk->sk_bound_dev_if;
 221         const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 222         struct net *net = sock_net(sk);
 223         const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
 224                                                 inet->inet_dport);
 225         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 226         spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 227         struct sock *sk2;
 228         const struct hlist_nulls_node *node;
 229         struct inet_timewait_sock *tw = NULL;
 230
 231         spin_lock(lock);
 232
 233         sk_nulls_for_each(sk2, node, &head->chain) {
 234                 if (sk2->sk_hash != hash)
 235                         continue;
 236
 237                 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) {
 238                         if (sk2->sk_state == TCP_TIME_WAIT) {
 239                                 tw = inet_twsk(sk2);
 240                                 if (twsk_unique(sk, sk2, twp))
 241                                         break;
 242                         }
 243                         goto not_unique;
 244                 }
 245         }
 246
 247         /* Must record num and sport now. Otherwise we will see
 248          * in hash table socket with a funny identity.
 249          */
 250         inet->inet_num = lport;
 251         inet->inet_sport = htons(lport);
 252         sk->sk_hash = hash;
 253         WARN_ON(!sk_unhashed(sk));
 254         __sk_nulls_add_node_rcu(sk, &head->chain);
 255         if (tw) {
 256                 sk_nulls_del_node_init_rcu((struct sock *)tw);
 257                 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
 258         }
 259         spin_unlock(lock);
 260         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 261
 262         if (twp) {
 263                 *twp = tw;
 264         } else if (tw) {
 265                 /* Silly. Should hash-dance instead... */
 266                 inet_twsk_deschedule_put(tw);
 267         }
 268         return 0;
 269
 270 not_unique:
 271         spin_unlock(lock);
 272         return -EADDRNOTAVAIL;
 273 }
 274
 275 static u32 inet6_sk_port_offset(const struct sock *sk)
 276 {
 277         const struct inet_sock *inet = inet_sk(sk);
 278
 279         return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
 280                                           sk->sk_v6_daddr.s6_addr32,
 281                                           inet->inet_dport);
 282 }
 283
 284 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 285                        struct sock *sk)
 286 {
 287         u32 port_offset = 0;
 288
 289         if (!inet_sk(sk)->inet_num)
 290                 port_offset = inet6_sk_port_offset(sk);
 291         return __inet_hash_connect(death_row, sk, port_offset,
 292                                    __inet6_check_established);
 293 }
 294 EXPORT_SYMBOL_GPL(inet6_hash_connect);
 295
 296 int inet6_hash(struct sock *sk)
 297 {
 298         if (sk->sk_state != TCP_CLOSE) {
 299                 local_bh_disable();
 300                 __inet_hash(sk, NULL, ipv6_rcv_saddr_equal);
 301                 local_bh_enable();
 302         }
 303
 304         return 0;
 305 }
 306 EXPORT_SYMBOL_GPL(inet6_hash);
 307
 308 /* match_wildcard == true:  IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6
 309  *                          only, and any IPv4 addresses if not IPv6 only
 310  * match_wildcard == false: addresses must be exactly the same, i.e.
 311  *                          IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
 312  *                          and 0.0.0.0 equals to 0.0.0.0 only
 313  */
 314 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
 315                          bool match_wildcard)
 316 {
 317         const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
 318         int sk2_ipv6only = inet_v6_ipv6only(sk2);
 319         int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
 320         int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
 321
 322         /* if both are mapped, treat as IPv4 */
 323         if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
 324                 if (!sk2_ipv6only) {
 325                         if (sk->sk_rcv_saddr == sk2->sk_rcv_saddr)
 326                                 return 1;
 327                         if (!sk->sk_rcv_saddr || !sk2->sk_rcv_saddr)
 328                                 return match_wildcard;
 329                 }
 330                 return 0;
 331         }
 332
 333         if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
 334                 return 1;
 335
 336         if (addr_type2 == IPV6_ADDR_ANY && match_wildcard &&
 337             !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
 338                 return 1;
 339
 340         if (addr_type == IPV6_ADDR_ANY && match_wildcard &&
 341             !(ipv6_only_sock(sk) && addr_type2 == IPV6_ADDR_MAPPED))
 342                 return 1;
 343
 344         if (sk2_rcv_saddr6 &&
 345             ipv6_addr_equal(&sk->sk_v6_rcv_saddr, sk2_rcv_saddr6))
 346                 return 1;
 347
 348         return 0;
 349 }
 350 EXPORT_SYMBOL_GPL(ipv6_rcv_saddr_equal);