linux/net/ipv6/inet6_hashtables.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4 *              operating system.  INET is implemented using the BSD Socket
   5 *              interface as the means of communication with the user level.
   6 *
   7 *              Generic INET6 transport hashtables
   8 *
   9 * Authors:     Lotsa people, from code originally in tcp, generalised here
  10 *              by Arnaldo Carvalho de Melo <acme@mandriva.com>
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/random.h>
  15
  16#include <net/addrconf.h>
  17#include <net/inet_connection_sock.h>
  18#include <net/inet_hashtables.h>
  19#include <net/inet6_hashtables.h>
  20#include <net/secure_seq.h>
  21#include <net/ip.h>
  22#include <net/sock_reuseport.h>
  23
  24u32 inet6_ehashfn(const struct net *net,
  25                  const struct in6_addr *laddr, const u16 lport,
  26                  const struct in6_addr *faddr, const __be16 fport)
  27{
  28        static u32 inet6_ehash_secret __read_mostly;
  29        static u32 ipv6_hash_secret __read_mostly;
  30
  31        u32 lhash, fhash;
  32
  33        net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
  34        net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
  35
  36        lhash = (__force u32)laddr->s6_addr32[3];
  37        fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
  38
  39        return __inet6_ehashfn(lhash, lport, fhash, fport,
  40                               inet6_ehash_secret + net_hash_mix(net));
  41}
  42
  43/*
  44 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  45 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  46 *
  47 * The sockhash lock must be held as a reader here.
  48 */
  49struct sock *__inet6_lookup_established(struct net *net,
  50                                        struct inet_hashinfo *hashinfo,
  51                                           const struct in6_addr *saddr,
  52                                           const __be16 sport,
  53                                           const struct in6_addr *daddr,
  54                                           const u16 hnum,
  55                                           const int dif, const int sdif)
  56{
  57        struct sock *sk;
  58        const struct hlist_nulls_node *node;
  59        const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
  60        /* Optimize here for direct hit, only listening connections can
  61         * have wildcards anyways.
  62         */
  63        unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
  64        unsigned int slot = hash & hashinfo->ehash_mask;
  65        struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
  66
  67
  68begin:
  69        sk_nulls_for_each_rcu(sk, node, &head->chain) {
  70                if (sk->sk_hash != hash)
  71                        continue;
  72                if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif, sdif))
  73                        continue;
  74                if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
  75                        goto out;
  76
  77                if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif, sdif))) {
  78                        sock_gen_put(sk);
  79                        goto begin;
  80                }
  81                goto found;
  82        }
  83        if (get_nulls_value(node) != slot)
  84                goto begin;
  85out:
  86        sk = NULL;
  87found:
  88        return sk;
  89}
  90EXPORT_SYMBOL(__inet6_lookup_established);
  91
  92static inline int compute_score(struct sock *sk, struct net *net,
  93                                const unsigned short hnum,
  94                                const struct in6_addr *daddr,
  95                                const int dif, const int sdif, bool exact_dif)
  96{
  97        int score = -1;
  98
  99        if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
 100            sk->sk_family == PF_INET6) {
 101                if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 102                        return -1;
 103
 104                if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
 105                        return -1;
 106
 107                score = 1;
 108                if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
 109                        score++;
 110        }
 111        return score;
 112}
 113
 114/* called with rcu_read_lock() */
 115static struct sock *inet6_lhash2_lookup(struct net *net,
 116                struct inet_listen_hashbucket *ilb2,
 117                struct sk_buff *skb, int doff,
 118                const struct in6_addr *saddr,
 119                const __be16 sport, const struct in6_addr *daddr,
 120                const unsigned short hnum, const int dif, const int sdif)
 121{
 122        bool exact_dif = inet6_exact_dif_match(net, skb);
 123        struct inet_connection_sock *icsk;
 124        struct sock *sk, *result = NULL;
 125        int score, hiscore = 0;
 126        u32 phash = 0;
 127
 128        inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
 129                sk = (struct sock *)icsk;
 130                score = compute_score(sk, net, hnum, daddr, dif, sdif,
 131                                      exact_dif);
 132                if (score > hiscore) {
 133                        if (sk->sk_reuseport) {
 134                                phash = inet6_ehashfn(net, daddr, hnum,
 135                                                      saddr, sport);
 136                                result = reuseport_select_sock(sk, phash,
 137                                                               skb, doff);
 138                                if (result)
 139                                        return result;
 140                        }
 141                        result = sk;
 142                        hiscore = score;
 143                }
 144        }
 145
 146        return result;
 147}
 148
 149struct sock *inet6_lookup_listener(struct net *net,
 150                struct inet_hashinfo *hashinfo,
 151                struct sk_buff *skb, int doff,
 152                const struct in6_addr *saddr,
 153                const __be16 sport, const struct in6_addr *daddr,
 154                const unsigned short hnum, const int dif, const int sdif)
 155{
 156        struct inet_listen_hashbucket *ilb2;
 157        struct sock *result = NULL;
 158        unsigned int hash2;
 159
 160        hash2 = ipv6_portaddr_hash(net, daddr, hnum);
 161        ilb2 = inet_lhash2_bucket(hashinfo, hash2);
 162
 163        result = inet6_lhash2_lookup(net, ilb2, skb, doff,
 164                                     saddr, sport, daddr, hnum,
 165                                     dif, sdif);
 166        if (result)
 167                goto done;
 168
 169        /* Lookup lhash2 with in6addr_any */
 170        hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
 171        ilb2 = inet_lhash2_bucket(hashinfo, hash2);
 172
 173        result = inet6_lhash2_lookup(net, ilb2, skb, doff,
 174                                     saddr, sport, &in6addr_any, hnum,
 175                                     dif, sdif);
 176done:
 177        if (IS_ERR(result))
 178                return NULL;
 179        return result;
 180}
 181EXPORT_SYMBOL_GPL(inet6_lookup_listener);
 182
 183struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
 184                          struct sk_buff *skb, int doff,
 185                          const struct in6_addr *saddr, const __be16 sport,
 186                          const struct in6_addr *daddr, const __be16 dport,
 187                          const int dif)
 188{
 189        struct sock *sk;
 190        bool refcounted;
 191
 192        sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
 193                            ntohs(dport), dif, 0, &refcounted);
 194        if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
 195                sk = NULL;
 196        return sk;
 197}
 198EXPORT_SYMBOL_GPL(inet6_lookup);
 199
 200static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 201                                     struct sock *sk, const __u16 lport,
 202                                     struct inet_timewait_sock **twp)
 203{
 204        struct inet_hashinfo *hinfo = death_row->hashinfo;
 205        struct inet_sock *inet = inet_sk(sk);
 206        const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr;
 207        const struct in6_addr *saddr = &sk->sk_v6_daddr;
 208        const int dif = sk->sk_bound_dev_if;
 209        struct net *net = sock_net(sk);
 210        const int sdif = l3mdev_master_ifindex_by_index(net, dif);
 211        const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 212        const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
 213                                                inet->inet_dport);
 214        struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 215        spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 216        struct sock *sk2;
 217        const struct hlist_nulls_node *node;
 218        struct inet_timewait_sock *tw = NULL;
 219
 220        spin_lock(lock);
 221
 222        sk_nulls_for_each(sk2, node, &head->chain) {
 223                if (sk2->sk_hash != hash)
 224                        continue;
 225
 226                if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports,
 227                                       dif, sdif))) {
 228                        if (sk2->sk_state == TCP_TIME_WAIT) {
 229                                tw = inet_twsk(sk2);
 230                                if (twsk_unique(sk, sk2, twp))
 231                                        break;
 232                        }
 233                        goto not_unique;
 234                }
 235        }
 236
 237        /* Must record num and sport now. Otherwise we will see
 238         * in hash table socket with a funny identity.
 239         */
 240        inet->inet_num = lport;
 241        inet->inet_sport = htons(lport);
 242        sk->sk_hash = hash;
 243        WARN_ON(!sk_unhashed(sk));
 244        __sk_nulls_add_node_rcu(sk, &head->chain);
 245        if (tw) {
 246                sk_nulls_del_node_init_rcu((struct sock *)tw);
 247                __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
 248        }
 249        spin_unlock(lock);
 250        sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 251
 252        if (twp) {
 253                *twp = tw;
 254        } else if (tw) {
 255                /* Silly. Should hash-dance instead... */
 256                inet_twsk_deschedule_put(tw);
 257        }
 258        return 0;
 259
 260not_unique:
 261        spin_unlock(lock);
 262        return -EADDRNOTAVAIL;
 263}
 264
 265static u32 inet6_sk_port_offset(const struct sock *sk)
 266{
 267        const struct inet_sock *inet = inet_sk(sk);
 268
 269        return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
 270                                          sk->sk_v6_daddr.s6_addr32,
 271                                          inet->inet_dport);
 272}
 273
 274int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 275                       struct sock *sk)
 276{
 277        u32 port_offset = 0;
 278
 279        if (!inet_sk(sk)->inet_num)
 280                port_offset = inet6_sk_port_offset(sk);
 281        return __inet_hash_connect(death_row, sk, port_offset,
 282                                   __inet6_check_established);
 283}
 284EXPORT_SYMBOL_GPL(inet6_hash_connect);
 285
 286int inet6_hash(struct sock *sk)
 287{
 288        int err = 0;
 289
 290        if (sk->sk_state != TCP_CLOSE) {
 291                local_bh_disable();
 292                err = __inet_hash(sk, NULL);
 293                local_bh_enable();
 294        }
 295
 296        return err;
 297}
 298EXPORT_SYMBOL_GPL(inet6_hash);
 299