net/ipv4/inet_hashtables.c

   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 INET transport hashtables
   8  *
   9  * Authors:     Lotsa people, from code originally in tcp
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/random.h>
  14 #include <linux/sched.h>
  15 #include <linux/slab.h>
  16 #include <linux/wait.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/memblock.h>
  19
  20 #include <net/addrconf.h>
  21 #include <net/inet_connection_sock.h>
  22 #include <net/inet_hashtables.h>
  23 #include <net/secure_seq.h>
  24 #include <net/ip.h>
  25 #include <net/tcp.h>
  26 #include <net/sock_reuseport.h>
  27
  28 static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
  29                         const __u16 lport, const __be32 faddr,
  30                         const __be16 fport)
  31 {
  32         static u32 inet_ehash_secret __read_mostly;
  33
  34         net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
  35
  36         return __inet_ehashfn(laddr, lport, faddr, fport,
  37                               inet_ehash_secret + net_hash_mix(net));
  38 }
  39
  40 /* This function handles inet_sock, but also timewait and request sockets
  41  * for IPv4/IPv6.
  42  */
  43 static u32 sk_ehashfn(const struct sock *sk)
  44 {
  45 #if IS_ENABLED(CONFIG_IPV6)
  46         if (sk->sk_family == AF_INET6 &&
  47             !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
  48                 return inet6_ehashfn(sock_net(sk),
  49                                      &sk->sk_v6_rcv_saddr, sk->sk_num,
  50                                      &sk->sk_v6_daddr, sk->sk_dport);
  51 #endif
  52         return inet_ehashfn(sock_net(sk),
  53                             sk->sk_rcv_saddr, sk->sk_num,
  54                             sk->sk_daddr, sk->sk_dport);
  55 }
  56
  57 /*
  58  * Allocate and initialize a new local port bind bucket.
  59  * The bindhash mutex for snum's hash chain must be held here.
  60  */
  61 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
  62                                                  struct net *net,
  63                                                  struct inet_bind_hashbucket *head,
  64                                                  const unsigned short snum,
  65                                                  int l3mdev)
  66 {
  67         struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
  68
  69         if (tb) {
  70                 write_pnet(&tb->ib_net, net);
  71                 tb->l3mdev    = l3mdev;
  72                 tb->port      = snum;
  73                 tb->fastreuse = 0;
  74                 tb->fastreuseport = 0;
  75                 INIT_HLIST_HEAD(&tb->owners);
  76                 hlist_add_head(&tb->node, &head->chain);
  77         }
  78         return tb;
  79 }
  80
  81 /*
  82  * Caller must hold hashbucket lock for this tb with local BH disabled
  83  */
  84 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
  85 {
  86         if (hlist_empty(&tb->owners)) {
  87                 __hlist_del(&tb->node);
  88                 kmem_cache_free(cachep, tb);
  89         }
  90 }
  91
  92 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
  93                     const unsigned short snum)
  94 {
  95         inet_sk(sk)->inet_num = snum;
  96         sk_add_bind_node(sk, &tb->owners);
  97         inet_csk(sk)->icsk_bind_hash = tb;
  98 }
  99
 100 /*
 101  * Get rid of any references to a local port held by the given sock.
 102  */
 103 static void __inet_put_port(struct sock *sk)
 104 {
 105         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 106         const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
 107                         hashinfo->bhash_size);
 108         struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
 109         struct inet_bind_bucket *tb;
 110
 111         spin_lock(&head->lock);
 112         tb = inet_csk(sk)->icsk_bind_hash;
 113         __sk_del_bind_node(sk);
 114         inet_csk(sk)->icsk_bind_hash = NULL;
 115         inet_sk(sk)->inet_num = 0;
 116         inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
 117         spin_unlock(&head->lock);
 118 }
 119
 120 void inet_put_port(struct sock *sk)
 121 {
 122         local_bh_disable();
 123         __inet_put_port(sk);
 124         local_bh_enable();
 125 }
 126 EXPORT_SYMBOL(inet_put_port);
 127
 128 int __inet_inherit_port(const struct sock *sk, struct sock *child)
 129 {
 130         struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
 131         unsigned short port = inet_sk(child)->inet_num;
 132         const int bhash = inet_bhashfn(sock_net(sk), port,
 133                         table->bhash_size);
 134         struct inet_bind_hashbucket *head = &table->bhash[bhash];
 135         struct inet_bind_bucket *tb;
 136         int l3mdev;
 137
 138         spin_lock(&head->lock);
 139         tb = inet_csk(sk)->icsk_bind_hash;
 140         if (unlikely(!tb)) {
 141                 spin_unlock(&head->lock);
 142                 return -ENOENT;
 143         }
 144         if (tb->port != port) {
 145                 l3mdev = inet_sk_bound_l3mdev(sk);
 146
 147                 /* NOTE: using tproxy and redirecting skbs to a proxy
 148                  * on a different listener port breaks the assumption
 149                  * that the listener socket's icsk_bind_hash is the same
 150                  * as that of the child socket. We have to look up or
 151                  * create a new bind bucket for the child here. */
 152                 inet_bind_bucket_for_each(tb, &head->chain) {
 153                         if (net_eq(ib_net(tb), sock_net(sk)) &&
 154                             tb->l3mdev == l3mdev && tb->port == port)
 155                                 break;
 156                 }
 157                 if (!tb) {
 158                         tb = inet_bind_bucket_create(table->bind_bucket_cachep,
 159                                                      sock_net(sk), head, port,
 160                                                      l3mdev);
 161                         if (!tb) {
 162                                 spin_unlock(&head->lock);
 163                                 return -ENOMEM;
 164                         }
 165                 }
 166         }
 167         inet_bind_hash(child, tb, port);
 168         spin_unlock(&head->lock);
 169
 170         return 0;
 171 }
 172 EXPORT_SYMBOL_GPL(__inet_inherit_port);
 173
 174 static struct inet_listen_hashbucket *
 175 inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk)
 176 {
 177         u32 hash;
 178
 179 #if IS_ENABLED(CONFIG_IPV6)
 180         if (sk->sk_family == AF_INET6)
 181                 hash = ipv6_portaddr_hash(sock_net(sk),
 182                                           &sk->sk_v6_rcv_saddr,
 183                                           inet_sk(sk)->inet_num);
 184         else
 185 #endif
 186                 hash = ipv4_portaddr_hash(sock_net(sk),
 187                                           inet_sk(sk)->inet_rcv_saddr,
 188                                           inet_sk(sk)->inet_num);
 189         return inet_lhash2_bucket(h, hash);
 190 }
 191
 192 static void inet_hash2(struct inet_hashinfo *h, struct sock *sk)
 193 {
 194         struct inet_listen_hashbucket *ilb2;
 195
 196         if (!h->lhash2)
 197                 return;
 198
 199         ilb2 = inet_lhash2_bucket_sk(h, sk);
 200
 201         spin_lock(&ilb2->lock);
 202         if (sk->sk_reuseport && sk->sk_family == AF_INET6)
 203                 hlist_add_tail_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
 204                                    &ilb2->head);
 205         else
 206                 hlist_add_head_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
 207                                    &ilb2->head);
 208         ilb2->count++;
 209         spin_unlock(&ilb2->lock);
 210 }
 211
 212 static void inet_unhash2(struct inet_hashinfo *h, struct sock *sk)
 213 {
 214         struct inet_listen_hashbucket *ilb2;
 215
 216         if (!h->lhash2 ||
 217             WARN_ON_ONCE(hlist_unhashed(&inet_csk(sk)->icsk_listen_portaddr_node)))
 218                 return;
 219
 220         ilb2 = inet_lhash2_bucket_sk(h, sk);
 221
 222         spin_lock(&ilb2->lock);
 223         hlist_del_init_rcu(&inet_csk(sk)->icsk_listen_portaddr_node);
 224         ilb2->count--;
 225         spin_unlock(&ilb2->lock);
 226 }
 227
 228 static inline int compute_score(struct sock *sk, struct net *net,
 229                                 const unsigned short hnum, const __be32 daddr,
 230                                 const int dif, const int sdif, bool exact_dif)
 231 {
 232         int score = -1;
 233
 234         if (net_eq(sock_net(sk), net) && sk->sk_num == hnum &&
 235                         !ipv6_only_sock(sk)) {
 236                 if (sk->sk_rcv_saddr != daddr)
 237                         return -1;
 238
 239                 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
 240                         return -1;
 241
 242                 score = sk->sk_family == PF_INET ? 2 : 1;
 243                 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
 244                         score++;
 245         }
 246         return score;
 247 }
 248
 249 /*
 250  * Here are some nice properties to exploit here. The BSD API
 251  * does not allow a listening sock to specify the remote port nor the
 252  * remote address for the connection. So always assume those are both
 253  * wildcarded during the search since they can never be otherwise.
 254  */
 255
 256 /* called with rcu_read_lock() : No refcount taken on the socket */
 257 static struct sock *inet_lhash2_lookup(struct net *net,
 258                                 struct inet_listen_hashbucket *ilb2,
 259                                 struct sk_buff *skb, int doff,
 260                                 const __be32 saddr, __be16 sport,
 261                                 const __be32 daddr, const unsigned short hnum,
 262                                 const int dif, const int sdif)
 263 {
 264         bool exact_dif = inet_exact_dif_match(net, skb);
 265         struct inet_connection_sock *icsk;
 266         struct sock *sk, *result = NULL;
 267         int score, hiscore = 0;
 268         u32 phash = 0;
 269
 270         inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
 271                 sk = (struct sock *)icsk;
 272                 score = compute_score(sk, net, hnum, daddr,
 273                                       dif, sdif, exact_dif);
 274                 if (score > hiscore) {
 275                         if (sk->sk_reuseport) {
 276                                 phash = inet_ehashfn(net, daddr, hnum,
 277                                                      saddr, sport);
 278                                 result = reuseport_select_sock(sk, phash,
 279                                                                skb, doff);
 280                                 if (result)
 281                                         return result;
 282                         }
 283                         result = sk;
 284                         hiscore = score;
 285                 }
 286         }
 287
 288         return result;
 289 }
 290
 291 struct sock *__inet_lookup_listener(struct net *net,
 292                                     struct inet_hashinfo *hashinfo,
 293                                     struct sk_buff *skb, int doff,
 294                                     const __be32 saddr, __be16 sport,
 295                                     const __be32 daddr, const unsigned short hnum,
 296                                     const int dif, const int sdif)
 297 {
 298         struct inet_listen_hashbucket *ilb2;
 299         struct sock *result = NULL;
 300         unsigned int hash2;
 301
 302         hash2 = ipv4_portaddr_hash(net, daddr, hnum);
 303         ilb2 = inet_lhash2_bucket(hashinfo, hash2);
 304
 305         result = inet_lhash2_lookup(net, ilb2, skb, doff,
 306                                     saddr, sport, daddr, hnum,
 307                                     dif, sdif);
 308         if (result)
 309                 goto done;
 310
 311         /* Lookup lhash2 with INADDR_ANY */
 312         hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
 313         ilb2 = inet_lhash2_bucket(hashinfo, hash2);
 314
 315         result = inet_lhash2_lookup(net, ilb2, skb, doff,
 316                                     saddr, sport, htonl(INADDR_ANY), hnum,
 317                                     dif, sdif);
 318 done:
 319         if (IS_ERR(result))
 320                 return NULL;
 321         return result;
 322 }
 323 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
 324
 325 /* All sockets share common refcount, but have different destructors */
 326 void sock_gen_put(struct sock *sk)
 327 {
 328         if (!refcount_dec_and_test(&sk->sk_refcnt))
 329                 return;
 330
 331         if (sk->sk_state == TCP_TIME_WAIT)
 332                 inet_twsk_free(inet_twsk(sk));
 333         else if (sk->sk_state == TCP_NEW_SYN_RECV)
 334                 reqsk_free(inet_reqsk(sk));
 335         else
 336                 sk_free(sk);
 337 }
 338 EXPORT_SYMBOL_GPL(sock_gen_put);
 339
 340 void sock_edemux(struct sk_buff *skb)
 341 {
 342         sock_gen_put(skb->sk);
 343 }
 344 EXPORT_SYMBOL(sock_edemux);
 345
 346 struct sock *__inet_lookup_established(struct net *net,
 347                                   struct inet_hashinfo *hashinfo,
 348                                   const __be32 saddr, const __be16 sport,
 349                                   const __be32 daddr, const u16 hnum,
 350                                   const int dif, const int sdif)
 351 {
 352         INET_ADDR_COOKIE(acookie, saddr, daddr);
 353         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
 354         struct sock *sk;
 355         const struct hlist_nulls_node *node;
 356         /* Optimize here for direct hit, only listening connections can
 357          * have wildcards anyways.
 358          */
 359         unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
 360         unsigned int slot = hash & hashinfo->ehash_mask;
 361         struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 362
 363 begin:
 364         sk_nulls_for_each_rcu(sk, node, &head->chain) {
 365                 if (sk->sk_hash != hash)
 366                         continue;
 367                 if (likely(INET_MATCH(sk, net, acookie,
 368                                       saddr, daddr, ports, dif, sdif))) {
 369                         if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
 370                                 goto out;
 371                         if (unlikely(!INET_MATCH(sk, net, acookie,
 372                                                  saddr, daddr, ports,
 373                                                  dif, sdif))) {
 374                                 sock_gen_put(sk);
 375                                 goto begin;
 376                         }
 377                         goto found;
 378                 }
 379         }
 380         /*
 381          * if the nulls value we got at the end of this lookup is
 382          * not the expected one, we must restart lookup.
 383          * We probably met an item that was moved to another chain.
 384          */
 385         if (get_nulls_value(node) != slot)
 386                 goto begin;
 387 out:
 388         sk = NULL;
 389 found:
 390         return sk;
 391 }
 392 EXPORT_SYMBOL_GPL(__inet_lookup_established);
 393
 394 /* called with local bh disabled */
 395 static int __inet_check_established(struct inet_timewait_death_row *death_row,
 396                                     struct sock *sk, __u16 lport,
 397                                     struct inet_timewait_sock **twp)
 398 {
 399         struct inet_hashinfo *hinfo = death_row->hashinfo;
 400         struct inet_sock *inet = inet_sk(sk);
 401         __be32 daddr = inet->inet_rcv_saddr;
 402         __be32 saddr = inet->inet_daddr;
 403         int dif = sk->sk_bound_dev_if;
 404         struct net *net = sock_net(sk);
 405         int sdif = l3mdev_master_ifindex_by_index(net, dif);
 406         INET_ADDR_COOKIE(acookie, saddr, daddr);
 407         const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 408         unsigned int hash = inet_ehashfn(net, daddr, lport,
 409                                          saddr, inet->inet_dport);
 410         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 411         spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 412         struct sock *sk2;
 413         const struct hlist_nulls_node *node;
 414         struct inet_timewait_sock *tw = NULL;
 415
 416         spin_lock(lock);
 417
 418         sk_nulls_for_each(sk2, node, &head->chain) {
 419                 if (sk2->sk_hash != hash)
 420                         continue;
 421
 422                 if (likely(INET_MATCH(sk2, net, acookie,
 423                                          saddr, daddr, ports, dif, sdif))) {
 424                         if (sk2->sk_state == TCP_TIME_WAIT) {
 425                                 tw = inet_twsk(sk2);
 426                                 if (twsk_unique(sk, sk2, twp))
 427                                         break;
 428                         }
 429                         goto not_unique;
 430                 }
 431         }
 432
 433         /* Must record num and sport now. Otherwise we will see
 434          * in hash table socket with a funny identity.
 435          */
 436         inet->inet_num = lport;
 437         inet->inet_sport = htons(lport);
 438         sk->sk_hash = hash;
 439         WARN_ON(!sk_unhashed(sk));
 440         __sk_nulls_add_node_rcu(sk, &head->chain);
 441         if (tw) {
 442                 sk_nulls_del_node_init_rcu((struct sock *)tw);
 443                 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
 444         }
 445         spin_unlock(lock);
 446         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 447
 448         if (twp) {
 449                 *twp = tw;
 450         } else if (tw) {
 451                 /* Silly. Should hash-dance instead... */
 452                 inet_twsk_deschedule_put(tw);
 453         }
 454         return 0;
 455
 456 not_unique:
 457         spin_unlock(lock);
 458         return -EADDRNOTAVAIL;
 459 }
 460
 461 static u32 inet_sk_port_offset(const struct sock *sk)
 462 {
 463         const struct inet_sock *inet = inet_sk(sk);
 464
 465         return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
 466                                           inet->inet_daddr,
 467                                           inet->inet_dport);
 468 }
 469
 470 /* insert a socket into ehash, and eventually remove another one
 471  * (The another one can be a SYN_RECV or TIMEWAIT
 472  */
 473 bool inet_ehash_insert(struct sock *sk, struct sock *osk)
 474 {
 475         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 476         struct hlist_nulls_head *list;
 477         struct inet_ehash_bucket *head;
 478         spinlock_t *lock;
 479         bool ret = true;
 480
 481         WARN_ON_ONCE(!sk_unhashed(sk));
 482
 483         sk->sk_hash = sk_ehashfn(sk);
 484         head = inet_ehash_bucket(hashinfo, sk->sk_hash);
 485         list = &head->chain;
 486         lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 487
 488         spin_lock(lock);
 489         if (osk) {
 490                 WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
 491                 ret = sk_nulls_del_node_init_rcu(osk);
 492         }
 493         if (ret)
 494                 __sk_nulls_add_node_rcu(sk, list);
 495         spin_unlock(lock);
 496         return ret;
 497 }
 498
 499 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
 500 {
 501         bool ok = inet_ehash_insert(sk, osk);
 502
 503         if (ok) {
 504                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 505         } else {
 506                 percpu_counter_inc(sk->sk_prot->orphan_count);
 507                 inet_sk_set_state(sk, TCP_CLOSE);
 508                 sock_set_flag(sk, SOCK_DEAD);
 509                 inet_csk_destroy_sock(sk);
 510         }
 511         return ok;
 512 }
 513 EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
 514
 515 static int inet_reuseport_add_sock(struct sock *sk,
 516                                    struct inet_listen_hashbucket *ilb)
 517 {
 518         struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
 519         struct sock *sk2;
 520         kuid_t uid = sock_i_uid(sk);
 521
 522         sk_for_each_rcu(sk2, &ilb->head) {
 523                 if (sk2 != sk &&
 524                     sk2->sk_family == sk->sk_family &&
 525                     ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
 526                     sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
 527                     inet_csk(sk2)->icsk_bind_hash == tb &&
 528                     sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
 529                     inet_rcv_saddr_equal(sk, sk2, false))
 530                         return reuseport_add_sock(sk, sk2,
 531                                                   inet_rcv_saddr_any(sk));
 532         }
 533
 534         return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
 535 }
 536
 537 int __inet_hash(struct sock *sk, struct sock *osk)
 538 {
 539         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 540         struct inet_listen_hashbucket *ilb;
 541         int err = 0;
 542
 543         if (sk->sk_state != TCP_LISTEN) {
 544                 inet_ehash_nolisten(sk, osk);
 545                 return 0;
 546         }
 547         WARN_ON(!sk_unhashed(sk));
 548         ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 549
 550         spin_lock(&ilb->lock);
 551         if (sk->sk_reuseport) {
 552                 err = inet_reuseport_add_sock(sk, ilb);
 553                 if (err)
 554                         goto unlock;
 555         }
 556         if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
 557                 sk->sk_family == AF_INET6)
 558                 hlist_add_tail_rcu(&sk->sk_node, &ilb->head);
 559         else
 560                 hlist_add_head_rcu(&sk->sk_node, &ilb->head);
 561         inet_hash2(hashinfo, sk);
 562         ilb->count++;
 563         sock_set_flag(sk, SOCK_RCU_FREE);
 564         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 565 unlock:
 566         spin_unlock(&ilb->lock);
 567
 568         return err;
 569 }
 570 EXPORT_SYMBOL(__inet_hash);
 571
 572 int inet_hash(struct sock *sk)
 573 {
 574         int err = 0;
 575
 576         if (sk->sk_state != TCP_CLOSE) {
 577                 local_bh_disable();
 578                 err = __inet_hash(sk, NULL);
 579                 local_bh_enable();
 580         }
 581
 582         return err;
 583 }
 584 EXPORT_SYMBOL_GPL(inet_hash);
 585
 586 void inet_unhash(struct sock *sk)
 587 {
 588         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 589         struct inet_listen_hashbucket *ilb = NULL;
 590         spinlock_t *lock;
 591
 592         if (sk_unhashed(sk))
 593                 return;
 594
 595         if (sk->sk_state == TCP_LISTEN) {
 596                 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 597                 lock = &ilb->lock;
 598         } else {
 599                 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 600         }
 601         spin_lock_bh(lock);
 602         if (sk_unhashed(sk))
 603                 goto unlock;
 604
 605         if (rcu_access_pointer(sk->sk_reuseport_cb))
 606                 reuseport_detach_sock(sk);
 607         if (ilb) {
 608                 inet_unhash2(hashinfo, sk);
 609                  __sk_del_node_init(sk);
 610                  ilb->count--;
 611         } else {
 612                 __sk_nulls_del_node_init_rcu(sk);
 613         }
 614         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 615 unlock:
 616         spin_unlock_bh(lock);
 617 }
 618 EXPORT_SYMBOL_GPL(inet_unhash);
 619
 620 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 621                 struct sock *sk, u32 port_offset,
 622                 int (*check_established)(struct inet_timewait_death_row *,
 623                         struct sock *, __u16, struct inet_timewait_sock **))
 624 {
 625         struct inet_hashinfo *hinfo = death_row->hashinfo;
 626         struct inet_timewait_sock *tw = NULL;
 627         struct inet_bind_hashbucket *head;
 628         int port = inet_sk(sk)->inet_num;
 629         struct net *net = sock_net(sk);
 630         struct inet_bind_bucket *tb;
 631         u32 remaining, offset;
 632         int ret, i, low, high;
 633         static u32 hint;
 634         int l3mdev;
 635
 636         if (port) {
 637                 head = &hinfo->bhash[inet_bhashfn(net, port,
 638                                                   hinfo->bhash_size)];
 639                 tb = inet_csk(sk)->icsk_bind_hash;
 640                 spin_lock_bh(&head->lock);
 641                 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
 642                         inet_ehash_nolisten(sk, NULL);
 643                         spin_unlock_bh(&head->lock);
 644                         return 0;
 645                 }
 646                 spin_unlock(&head->lock);
 647                 /* No definite answer... Walk to established hash table */
 648                 ret = check_established(death_row, sk, port, NULL);
 649                 local_bh_enable();
 650                 return ret;
 651         }
 652
 653         l3mdev = inet_sk_bound_l3mdev(sk);
 654
 655         inet_get_local_port_range(net, &low, &high);
 656         high++; /* [32768, 60999] -> [32768, 61000[ */
 657         remaining = high - low;
 658         if (likely(remaining > 1))
 659                 remaining &= ~1U;
 660
 661         offset = (hint + port_offset) % remaining;
 662         /* In first pass we try ports of @low parity.
 663          * inet_csk_get_port() does the opposite choice.
 664          */
 665         offset &= ~1U;
 666 other_parity_scan:
 667         port = low + offset;
 668         for (i = 0; i < remaining; i += 2, port += 2) {
 669                 if (unlikely(port >= high))
 670                         port -= remaining;
 671                 if (inet_is_local_reserved_port(net, port))
 672                         continue;
 673                 head = &hinfo->bhash[inet_bhashfn(net, port,
 674                                                   hinfo->bhash_size)];
 675                 spin_lock_bh(&head->lock);
 676
 677                 /* Does not bother with rcv_saddr checks, because
 678                  * the established check is already unique enough.
 679                  */
 680                 inet_bind_bucket_for_each(tb, &head->chain) {
 681                         if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
 682                             tb->port == port) {
 683                                 if (tb->fastreuse >= 0 ||
 684                                     tb->fastreuseport >= 0)
 685                                         goto next_port;
 686                                 WARN_ON(hlist_empty(&tb->owners));
 687                                 if (!check_established(death_row, sk,
 688                                                        port, &tw))
 689                                         goto ok;
 690                                 goto next_port;
 691                         }
 692                 }
 693
 694                 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
 695                                              net, head, port, l3mdev);
 696                 if (!tb) {
 697                         spin_unlock_bh(&head->lock);
 698                         return -ENOMEM;
 699                 }
 700                 tb->fastreuse = -1;
 701                 tb->fastreuseport = -1;
 702                 goto ok;
 703 next_port:
 704                 spin_unlock_bh(&head->lock);
 705                 cond_resched();
 706         }
 707
 708         offset++;
 709         if ((offset & 1) && remaining > 1)
 710                 goto other_parity_scan;
 711
 712         return -EADDRNOTAVAIL;
 713
 714 ok:
 715         hint += i + 2;
 716
 717         /* Head lock still held and bh's disabled */
 718         inet_bind_hash(sk, tb, port);
 719         if (sk_unhashed(sk)) {
 720                 inet_sk(sk)->inet_sport = htons(port);
 721                 inet_ehash_nolisten(sk, (struct sock *)tw);
 722         }
 723         if (tw)
 724                 inet_twsk_bind_unhash(tw, hinfo);
 725         spin_unlock(&head->lock);
 726         if (tw)
 727                 inet_twsk_deschedule_put(tw);
 728         local_bh_enable();
 729         return 0;
 730 }
 731
 732 /*
 733  * Bind a port for a connect operation and hash it.
 734  */
 735 int inet_hash_connect(struct inet_timewait_death_row *death_row,
 736                       struct sock *sk)
 737 {
 738         u32 port_offset = 0;
 739
 740         if (!inet_sk(sk)->inet_num)
 741                 port_offset = inet_sk_port_offset(sk);
 742         return __inet_hash_connect(death_row, sk, port_offset,
 743                                    __inet_check_established);
 744 }
 745 EXPORT_SYMBOL_GPL(inet_hash_connect);
 746
 747 void inet_hashinfo_init(struct inet_hashinfo *h)
 748 {
 749         int i;
 750
 751         for (i = 0; i < INET_LHTABLE_SIZE; i++) {
 752                 spin_lock_init(&h->listening_hash[i].lock);
 753                 INIT_HLIST_HEAD(&h->listening_hash[i].head);
 754                 h->listening_hash[i].count = 0;
 755         }
 756
 757         h->lhash2 = NULL;
 758 }
 759 EXPORT_SYMBOL_GPL(inet_hashinfo_init);
 760
 761 static void init_hashinfo_lhash2(struct inet_hashinfo *h)
 762 {
 763         int i;
 764
 765         for (i = 0; i <= h->lhash2_mask; i++) {
 766                 spin_lock_init(&h->lhash2[i].lock);
 767                 INIT_HLIST_HEAD(&h->lhash2[i].head);
 768                 h->lhash2[i].count = 0;
 769         }
 770 }
 771
 772 void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
 773                                 unsigned long numentries, int scale,
 774                                 unsigned long low_limit,
 775                                 unsigned long high_limit)
 776 {
 777         h->lhash2 = alloc_large_system_hash(name,
 778                                             sizeof(*h->lhash2),
 779                                             numentries,
 780                                             scale,
 781                                             0,
 782                                             NULL,
 783                                             &h->lhash2_mask,
 784                                             low_limit,
 785                                             high_limit);
 786         init_hashinfo_lhash2(h);
 787 }
 788
 789 int inet_hashinfo2_init_mod(struct inet_hashinfo *h)
 790 {
 791         h->lhash2 = kmalloc_array(INET_LHTABLE_SIZE, sizeof(*h->lhash2), GFP_KERNEL);
 792         if (!h->lhash2)
 793                 return -ENOMEM;
 794
 795         h->lhash2_mask = INET_LHTABLE_SIZE - 1;
 796         /* INET_LHTABLE_SIZE must be a power of 2 */
 797         BUG_ON(INET_LHTABLE_SIZE & h->lhash2_mask);
 798
 799         init_hashinfo_lhash2(h);
 800         return 0;
 801 }
 802 EXPORT_SYMBOL_GPL(inet_hashinfo2_init_mod);
 803
 804 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
 805 {
 806         unsigned int locksz = sizeof(spinlock_t);
 807         unsigned int i, nblocks = 1;
 808
 809         if (locksz != 0) {
 810                 /* allocate 2 cache lines or at least one spinlock per cpu */
 811                 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
 812                 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
 813
 814                 /* no more locks than number of hash buckets */
 815                 nblocks = min(nblocks, hashinfo->ehash_mask + 1);
 816
 817                 hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
 818                 if (!hashinfo->ehash_locks)
 819                         return -ENOMEM;
 820
 821                 for (i = 0; i < nblocks; i++)
 822                         spin_lock_init(&hashinfo->ehash_locks[i]);
 823         }
 824         hashinfo->ehash_locks_mask = nblocks - 1;
 825         return 0;
 826 }
 827 EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);