linux/net/ipv6/inet6_hashtables.c
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   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
  28u32 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 */
  53struct 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
  72begin:
  73        sk_nulls_for_each_rcu(sk, node, &head->chain) {
  74                if (sk->sk_hash != hash)
  75                        continue;
  76                if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif))
  77                        continue;
  78                if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
  79                        goto out;
  80
  81                if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif))) {
  82                        sock_gen_put(sk);
  83                        goto begin;
  84                }
  85                goto found;
  86        }
  87        if (get_nulls_value(node) != slot)
  88                goto begin;
  89out:
  90        sk = NULL;
  91found:
  92        return sk;
  93}
  94EXPORT_SYMBOL(__inet6_lookup_established);
  95
  96static inline int compute_score(struct sock *sk, struct net *net,
  97                                const unsigned short hnum,
  98                                const struct in6_addr *daddr,
  99                                const int dif)
 100{
 101        int score = -1;
 102
 103        if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
 104            sk->sk_family == PF_INET6) {
 105
 106                score = 1;
 107                if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
 108                        if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 109                                return -1;
 110                        score++;
 111                }
 112                if (sk->sk_bound_dev_if) {
 113                        if (sk->sk_bound_dev_if != dif)
 114                                return -1;
 115                        score++;
 116                }
 117                if (sk->sk_incoming_cpu == raw_smp_processor_id())
 118                        score++;
 119        }
 120        return score;
 121}
 122
 123/* called with rcu_read_lock() */
 124struct sock *inet6_lookup_listener(struct net *net,
 125                struct inet_hashinfo *hashinfo,
 126                struct sk_buff *skb, int doff,
 127                const struct in6_addr *saddr,
 128                const __be16 sport, const struct in6_addr *daddr,
 129                const unsigned short hnum, const int dif)
 130{
 131        unsigned int hash = inet_lhashfn(net, hnum);
 132        struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
 133        int score, hiscore = 0, matches = 0, reuseport = 0;
 134        struct sock *sk, *result = NULL;
 135        u32 phash = 0;
 136
 137        sk_for_each(sk, &ilb->head) {
 138                score = compute_score(sk, net, hnum, daddr, dif);
 139                if (score > hiscore) {
 140                        reuseport = sk->sk_reuseport;
 141                        if (reuseport) {
 142                                phash = inet6_ehashfn(net, daddr, hnum,
 143                                                      saddr, sport);
 144                                result = reuseport_select_sock(sk, phash,
 145                                                               skb, doff);
 146                                if (result)
 147                                        return result;
 148                                matches = 1;
 149                        }
 150                        result = sk;
 151                        hiscore = score;
 152                } else if (score == hiscore && reuseport) {
 153                        matches++;
 154                        if (reciprocal_scale(phash, matches) == 0)
 155                                result = sk;
 156                        phash = next_pseudo_random32(phash);
 157                }
 158        }
 159        return result;
 160}
 161EXPORT_SYMBOL_GPL(inet6_lookup_listener);
 162
 163struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
 164                          struct sk_buff *skb, int doff,
 165                          const struct in6_addr *saddr, const __be16 sport,
 166                          const struct in6_addr *daddr, const __be16 dport,
 167                          const int dif)
 168{
 169        struct sock *sk;
 170        bool refcounted;
 171
 172        sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
 173                            ntohs(dport), dif, &refcounted);
 174        if (sk && !refcounted && !atomic_inc_not_zero(&sk->sk_refcnt))
 175                sk = NULL;
 176        return sk;
 177}
 178EXPORT_SYMBOL_GPL(inet6_lookup);
 179
 180static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 181                                     struct sock *sk, const __u16 lport,
 182                                     struct inet_timewait_sock **twp)
 183{
 184        struct inet_hashinfo *hinfo = death_row->hashinfo;
 185        struct inet_sock *inet = inet_sk(sk);
 186        const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr;
 187        const struct in6_addr *saddr = &sk->sk_v6_daddr;
 188        const int dif = sk->sk_bound_dev_if;
 189        const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 190        struct net *net = sock_net(sk);
 191        const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
 192                                                inet->inet_dport);
 193        struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 194        spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 195        struct sock *sk2;
 196        const struct hlist_nulls_node *node;
 197        struct inet_timewait_sock *tw = NULL;
 198
 199        spin_lock(lock);
 200
 201        sk_nulls_for_each(sk2, node, &head->chain) {
 202                if (sk2->sk_hash != hash)
 203                        continue;
 204
 205                if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) {
 206                        if (sk2->sk_state == TCP_TIME_WAIT) {
 207                                tw = inet_twsk(sk2);
 208                                if (twsk_unique(sk, sk2, twp))
 209                                        break;
 210                        }
 211                        goto not_unique;
 212                }
 213        }
 214
 215        /* Must record num and sport now. Otherwise we will see
 216         * in hash table socket with a funny identity.
 217         */
 218        inet->inet_num = lport;
 219        inet->inet_sport = htons(lport);
 220        sk->sk_hash = hash;
 221        WARN_ON(!sk_unhashed(sk));
 222        __sk_nulls_add_node_rcu(sk, &head->chain);
 223        if (tw) {
 224                sk_nulls_del_node_init_rcu((struct sock *)tw);
 225                __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
 226        }
 227        spin_unlock(lock);
 228        sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 229
 230        if (twp) {
 231                *twp = tw;
 232        } else if (tw) {
 233                /* Silly. Should hash-dance instead... */
 234                inet_twsk_deschedule_put(tw);
 235        }
 236        return 0;
 237
 238not_unique:
 239        spin_unlock(lock);
 240        return -EADDRNOTAVAIL;
 241}
 242
 243static u32 inet6_sk_port_offset(const struct sock *sk)
 244{
 245        const struct inet_sock *inet = inet_sk(sk);
 246
 247        return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
 248                                          sk->sk_v6_daddr.s6_addr32,
 249                                          inet->inet_dport);
 250}
 251
 252int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 253                       struct sock *sk)
 254{
 255        u32 port_offset = 0;
 256
 257        if (!inet_sk(sk)->inet_num)
 258                port_offset = inet6_sk_port_offset(sk);
 259        return __inet_hash_connect(death_row, sk, port_offset,
 260                                   __inet6_check_established);
 261}
 262EXPORT_SYMBOL_GPL(inet6_hash_connect);
 263
 264int inet6_hash(struct sock *sk)
 265{
 266        if (sk->sk_state != TCP_CLOSE) {
 267                local_bh_disable();
 268                __inet_hash(sk, NULL, ipv6_rcv_saddr_equal);
 269                local_bh_enable();
 270        }
 271
 272        return 0;
 273}
 274EXPORT_SYMBOL_GPL(inet6_hash);
 275
 276/* match_wildcard == true:  IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6
 277 *                          only, and any IPv4 addresses if not IPv6 only
 278 * match_wildcard == false: addresses must be exactly the same, i.e.
 279 *                          IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY,
 280 *                          and 0.0.0.0 equals to 0.0.0.0 only
 281 */
 282int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
 283                         bool match_wildcard)
 284{
 285        const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
 286        int sk2_ipv6only = inet_v6_ipv6only(sk2);
 287        int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
 288        int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
 289
 290        /* if both are mapped, treat as IPv4 */
 291        if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) {
 292                if (!sk2_ipv6only) {
 293                        if (sk->sk_rcv_saddr == sk2->sk_rcv_saddr)
 294                                return 1;
 295                        if (!sk->sk_rcv_saddr || !sk2->sk_rcv_saddr)
 296                                return match_wildcard;
 297                }
 298                return 0;
 299        }
 300
 301        if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY)
 302                return 1;
 303
 304        if (addr_type2 == IPV6_ADDR_ANY && match_wildcard &&
 305            !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
 306                return 1;
 307
 308        if (addr_type == IPV6_ADDR_ANY && match_wildcard &&
 309            !(ipv6_only_sock(sk) && addr_type2 == IPV6_ADDR_MAPPED))
 310                return 1;
 311
 312        if (sk2_rcv_saddr6 &&
 313            ipv6_addr_equal(&sk->sk_v6_rcv_saddr, sk2_rcv_saddr6))
 314                return 1;
 315
 316        return 0;
 317}
 318EXPORT_SYMBOL_GPL(ipv6_rcv_saddr_equal);
 319