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 #if IS_ENABLED(CONFIG_IPV6)
  24 #include <net/inet6_hashtables.h>
  25 #endif
  26 #include <net/secure_seq.h>
  27 #include <net/ip.h>
  28 #include <net/tcp.h>
  29 #include <net/sock_reuseport.h>
  30
  31 static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
  32                         const __u16 lport, const __be32 faddr,
  33                         const __be16 fport)
  34 {
  35         static u32 inet_ehash_secret __read_mostly;
  36
  37         net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
  38
  39         return __inet_ehashfn(laddr, lport, faddr, fport,
  40                               inet_ehash_secret + net_hash_mix(net));
  41 }
  42
  43 /* This function handles inet_sock, but also timewait and request sockets
  44  * for IPv4/IPv6.
  45  */
  46 static u32 sk_ehashfn(const struct sock *sk)
  47 {
  48 #if IS_ENABLED(CONFIG_IPV6)
  49         if (sk->sk_family == AF_INET6 &&
  50             !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
  51                 return inet6_ehashfn(sock_net(sk),
  52                                      &sk->sk_v6_rcv_saddr, sk->sk_num,
  53                                      &sk->sk_v6_daddr, sk->sk_dport);
  54 #endif
  55         return inet_ehashfn(sock_net(sk),
  56                             sk->sk_rcv_saddr, sk->sk_num,
  57                             sk->sk_daddr, sk->sk_dport);
  58 }
  59
  60 /*
  61  * Allocate and initialize a new local port bind bucket.
  62  * The bindhash mutex for snum's hash chain must be held here.
  63  */
  64 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
  65                                                  struct net *net,
  66                                                  struct inet_bind_hashbucket *head,
  67                                                  const unsigned short snum,
  68                                                  int l3mdev)
  69 {
  70         struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
  71
  72         if (tb) {
  73                 write_pnet(&tb->ib_net, net);
  74                 tb->l3mdev    = l3mdev;
  75                 tb->port      = snum;
  76                 tb->fastreuse = 0;
  77                 tb->fastreuseport = 0;
  78                 INIT_HLIST_HEAD(&tb->owners);
  79                 hlist_add_head(&tb->node, &head->chain);
  80         }
  81         return tb;
  82 }
  83
  84 /*
  85  * Caller must hold hashbucket lock for this tb with local BH disabled
  86  */
  87 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
  88 {
  89         if (hlist_empty(&tb->owners)) {
  90                 __hlist_del(&tb->node);
  91                 kmem_cache_free(cachep, tb);
  92         }
  93 }
  94
  95 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
  96                     const unsigned short snum)
  97 {
  98         inet_sk(sk)->inet_num = snum;
  99         sk_add_bind_node(sk, &tb->owners);
 100         inet_csk(sk)->icsk_bind_hash = tb;
 101 }
 102
 103 /*
 104  * Get rid of any references to a local port held by the given sock.
 105  */
 106 static void __inet_put_port(struct sock *sk)
 107 {
 108         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 109         const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
 110                         hashinfo->bhash_size);
 111         struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
 112         struct inet_bind_bucket *tb;
 113
 114         spin_lock(&head->lock);
 115         tb = inet_csk(sk)->icsk_bind_hash;
 116         __sk_del_bind_node(sk);
 117         inet_csk(sk)->icsk_bind_hash = NULL;
 118         inet_sk(sk)->inet_num = 0;
 119         inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
 120         spin_unlock(&head->lock);
 121 }
 122
 123 void inet_put_port(struct sock *sk)
 124 {
 125         local_bh_disable();
 126         __inet_put_port(sk);
 127         local_bh_enable();
 128 }
 129 EXPORT_SYMBOL(inet_put_port);
 130
 131 int __inet_inherit_port(const struct sock *sk, struct sock *child)
 132 {
 133         struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
 134         unsigned short port = inet_sk(child)->inet_num;
 135         const int bhash = inet_bhashfn(sock_net(sk), port,
 136                         table->bhash_size);
 137         struct inet_bind_hashbucket *head = &table->bhash[bhash];
 138         struct inet_bind_bucket *tb;
 139         int l3mdev;
 140
 141         spin_lock(&head->lock);
 142         tb = inet_csk(sk)->icsk_bind_hash;
 143         if (unlikely(!tb)) {
 144                 spin_unlock(&head->lock);
 145                 return -ENOENT;
 146         }
 147         if (tb->port != port) {
 148                 l3mdev = inet_sk_bound_l3mdev(sk);
 149
 150                 /* NOTE: using tproxy and redirecting skbs to a proxy
 151                  * on a different listener port breaks the assumption
 152                  * that the listener socket's icsk_bind_hash is the same
 153                  * as that of the child socket. We have to look up or
 154                  * create a new bind bucket for the child here. */
 155                 inet_bind_bucket_for_each(tb, &head->chain) {
 156                         if (net_eq(ib_net(tb), sock_net(sk)) &&
 157                             tb->l3mdev == l3mdev && tb->port == port)
 158                                 break;
 159                 }
 160                 if (!tb) {
 161                         tb = inet_bind_bucket_create(table->bind_bucket_cachep,
 162                                                      sock_net(sk), head, port,
 163                                                      l3mdev);
 164                         if (!tb) {
 165                                 spin_unlock(&head->lock);
 166                                 return -ENOMEM;
 167                         }
 168                 }
 169                 inet_csk_update_fastreuse(tb, child);
 170         }
 171         inet_bind_hash(child, tb, port);
 172         spin_unlock(&head->lock);
 173
 174         return 0;
 175 }
 176 EXPORT_SYMBOL_GPL(__inet_inherit_port);
 177
 178 static struct inet_listen_hashbucket *
 179 inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk)
 180 {
 181         u32 hash;
 182
 183 #if IS_ENABLED(CONFIG_IPV6)
 184         if (sk->sk_family == AF_INET6)
 185                 hash = ipv6_portaddr_hash(sock_net(sk),
 186                                           &sk->sk_v6_rcv_saddr,
 187                                           inet_sk(sk)->inet_num);
 188         else
 189 #endif
 190                 hash = ipv4_portaddr_hash(sock_net(sk),
 191                                           inet_sk(sk)->inet_rcv_saddr,
 192                                           inet_sk(sk)->inet_num);
 193         return inet_lhash2_bucket(h, hash);
 194 }
 195
 196 static void inet_hash2(struct inet_hashinfo *h, struct sock *sk)
 197 {
 198         struct inet_listen_hashbucket *ilb2;
 199
 200         if (!h->lhash2)
 201                 return;
 202
 203         ilb2 = inet_lhash2_bucket_sk(h, sk);
 204
 205         spin_lock(&ilb2->lock);
 206         if (sk->sk_reuseport && sk->sk_family == AF_INET6)
 207                 hlist_add_tail_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
 208                                    &ilb2->head);
 209         else
 210                 hlist_add_head_rcu(&inet_csk(sk)->icsk_listen_portaddr_node,
 211                                    &ilb2->head);
 212         ilb2->count++;
 213         spin_unlock(&ilb2->lock);
 214 }
 215
 216 static void inet_unhash2(struct inet_hashinfo *h, struct sock *sk)
 217 {
 218         struct inet_listen_hashbucket *ilb2;
 219
 220         if (!h->lhash2 ||
 221             WARN_ON_ONCE(hlist_unhashed(&inet_csk(sk)->icsk_listen_portaddr_node)))
 222                 return;
 223
 224         ilb2 = inet_lhash2_bucket_sk(h, sk);
 225
 226         spin_lock(&ilb2->lock);
 227         hlist_del_init_rcu(&inet_csk(sk)->icsk_listen_portaddr_node);
 228         ilb2->count--;
 229         spin_unlock(&ilb2->lock);
 230 }
 231
 232 static inline int compute_score(struct sock *sk, struct net *net,
 233                                 const unsigned short hnum, const __be32 daddr,
 234                                 const int dif, const int sdif)
 235 {
 236         int score = -1;
 237
 238         if (net_eq(sock_net(sk), net) && sk->sk_num == hnum &&
 239                         !ipv6_only_sock(sk)) {
 240                 if (sk->sk_rcv_saddr != daddr)
 241                         return -1;
 242
 243                 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
 244                         return -1;
 245
 246                 score = sk->sk_family == PF_INET ? 2 : 1;
 247                 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
 248                         score++;
 249         }
 250         return score;
 251 }
 252
 253 static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
 254                                             struct sk_buff *skb, int doff,
 255                                             __be32 saddr, __be16 sport,
 256                                             __be32 daddr, unsigned short hnum)
 257 {
 258         struct sock *reuse_sk = NULL;
 259         u32 phash;
 260
 261         if (sk->sk_reuseport) {
 262                 phash = inet_ehashfn(net, daddr, hnum, saddr, sport);
 263                 reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
 264         }
 265         return reuse_sk;
 266 }
 267
 268 /*
 269  * Here are some nice properties to exploit here. The BSD API
 270  * does not allow a listening sock to specify the remote port nor the
 271  * remote address for the connection. So always assume those are both
 272  * wildcarded during the search since they can never be otherwise.
 273  */
 274
 275 /* called with rcu_read_lock() : No refcount taken on the socket */
 276 static struct sock *inet_lhash2_lookup(struct net *net,
 277                                 struct inet_listen_hashbucket *ilb2,
 278                                 struct sk_buff *skb, int doff,
 279                                 const __be32 saddr, __be16 sport,
 280                                 const __be32 daddr, const unsigned short hnum,
 281                                 const int dif, const int sdif)
 282 {
 283         struct inet_connection_sock *icsk;
 284         struct sock *sk, *result = NULL;
 285         int score, hiscore = 0;
 286
 287         inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) {
 288                 sk = (struct sock *)icsk;
 289                 score = compute_score(sk, net, hnum, daddr, dif, sdif);
 290                 if (score > hiscore) {
 291                         result = lookup_reuseport(net, sk, skb, doff,
 292                                                   saddr, sport, daddr, hnum);
 293                         if (result)
 294                                 return result;
 295
 296                         result = sk;
 297                         hiscore = score;
 298                 }
 299         }
 300
 301         return result;
 302 }
 303
 304 static inline struct sock *inet_lookup_run_bpf(struct net *net,
 305                                                struct inet_hashinfo *hashinfo,
 306                                                struct sk_buff *skb, int doff,
 307                                                __be32 saddr, __be16 sport,
 308                                                __be32 daddr, u16 hnum)
 309 {
 310         struct sock *sk, *reuse_sk;
 311         bool no_reuseport;
 312
 313         if (hashinfo != &tcp_hashinfo)
 314                 return NULL; /* only TCP is supported */
 315
 316         no_reuseport = bpf_sk_lookup_run_v4(net, IPPROTO_TCP,
 317                                             saddr, sport, daddr, hnum, &sk);
 318         if (no_reuseport || IS_ERR_OR_NULL(sk))
 319                 return sk;
 320
 321         reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
 322         if (reuse_sk)
 323                 sk = reuse_sk;
 324         return sk;
 325 }
 326
 327 struct sock *__inet_lookup_listener(struct net *net,
 328                                     struct inet_hashinfo *hashinfo,
 329                                     struct sk_buff *skb, int doff,
 330                                     const __be32 saddr, __be16 sport,
 331                                     const __be32 daddr, const unsigned short hnum,
 332                                     const int dif, const int sdif)
 333 {
 334         struct inet_listen_hashbucket *ilb2;
 335         struct sock *result = NULL;
 336         unsigned int hash2;
 337
 338         /* Lookup redirect from BPF */
 339         if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
 340                 result = inet_lookup_run_bpf(net, hashinfo, skb, doff,
 341                                              saddr, sport, daddr, hnum);
 342                 if (result)
 343                         goto done;
 344         }
 345
 346         hash2 = ipv4_portaddr_hash(net, daddr, hnum);
 347         ilb2 = inet_lhash2_bucket(hashinfo, hash2);
 348
 349         result = inet_lhash2_lookup(net, ilb2, skb, doff,
 350                                     saddr, sport, daddr, hnum,
 351                                     dif, sdif);
 352         if (result)
 353                 goto done;
 354
 355         /* Lookup lhash2 with INADDR_ANY */
 356         hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
 357         ilb2 = inet_lhash2_bucket(hashinfo, hash2);
 358
 359         result = inet_lhash2_lookup(net, ilb2, skb, doff,
 360                                     saddr, sport, htonl(INADDR_ANY), hnum,
 361                                     dif, sdif);
 362 done:
 363         if (IS_ERR(result))
 364                 return NULL;
 365         return result;
 366 }
 367 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
 368
 369 /* All sockets share common refcount, but have different destructors */
 370 void sock_gen_put(struct sock *sk)
 371 {
 372         if (!refcount_dec_and_test(&sk->sk_refcnt))
 373                 return;
 374
 375         if (sk->sk_state == TCP_TIME_WAIT)
 376                 inet_twsk_free(inet_twsk(sk));
 377         else if (sk->sk_state == TCP_NEW_SYN_RECV)
 378                 reqsk_free(inet_reqsk(sk));
 379         else
 380                 sk_free(sk);
 381 }
 382 EXPORT_SYMBOL_GPL(sock_gen_put);
 383
 384 void sock_edemux(struct sk_buff *skb)
 385 {
 386         sock_gen_put(skb->sk);
 387 }
 388 EXPORT_SYMBOL(sock_edemux);
 389
 390 struct sock *__inet_lookup_established(struct net *net,
 391                                   struct inet_hashinfo *hashinfo,
 392                                   const __be32 saddr, const __be16 sport,
 393                                   const __be32 daddr, const u16 hnum,
 394                                   const int dif, const int sdif)
 395 {
 396         INET_ADDR_COOKIE(acookie, saddr, daddr);
 397         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
 398         struct sock *sk;
 399         const struct hlist_nulls_node *node;
 400         /* Optimize here for direct hit, only listening connections can
 401          * have wildcards anyways.
 402          */
 403         unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
 404         unsigned int slot = hash & hashinfo->ehash_mask;
 405         struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 406
 407 begin:
 408         sk_nulls_for_each_rcu(sk, node, &head->chain) {
 409                 if (sk->sk_hash != hash)
 410                         continue;
 411                 if (likely(INET_MATCH(sk, net, acookie,
 412                                       saddr, daddr, ports, dif, sdif))) {
 413                         if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
 414                                 goto out;
 415                         if (unlikely(!INET_MATCH(sk, net, acookie,
 416                                                  saddr, daddr, ports,
 417                                                  dif, sdif))) {
 418                                 sock_gen_put(sk);
 419                                 goto begin;
 420                         }
 421                         goto found;
 422                 }
 423         }
 424         /*
 425          * if the nulls value we got at the end of this lookup is
 426          * not the expected one, we must restart lookup.
 427          * We probably met an item that was moved to another chain.
 428          */
 429         if (get_nulls_value(node) != slot)
 430                 goto begin;
 431 out:
 432         sk = NULL;
 433 found:
 434         return sk;
 435 }
 436 EXPORT_SYMBOL_GPL(__inet_lookup_established);
 437
 438 /* called with local bh disabled */
 439 static int __inet_check_established(struct inet_timewait_death_row *death_row,
 440                                     struct sock *sk, __u16 lport,
 441                                     struct inet_timewait_sock **twp)
 442 {
 443         struct inet_hashinfo *hinfo = death_row->hashinfo;
 444         struct inet_sock *inet = inet_sk(sk);
 445         __be32 daddr = inet->inet_rcv_saddr;
 446         __be32 saddr = inet->inet_daddr;
 447         int dif = sk->sk_bound_dev_if;
 448         struct net *net = sock_net(sk);
 449         int sdif = l3mdev_master_ifindex_by_index(net, dif);
 450         INET_ADDR_COOKIE(acookie, saddr, daddr);
 451         const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 452         unsigned int hash = inet_ehashfn(net, daddr, lport,
 453                                          saddr, inet->inet_dport);
 454         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 455         spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 456         struct sock *sk2;
 457         const struct hlist_nulls_node *node;
 458         struct inet_timewait_sock *tw = NULL;
 459
 460         spin_lock(lock);
 461
 462         sk_nulls_for_each(sk2, node, &head->chain) {
 463                 if (sk2->sk_hash != hash)
 464                         continue;
 465
 466                 if (likely(INET_MATCH(sk2, net, acookie,
 467                                          saddr, daddr, ports, dif, sdif))) {
 468                         if (sk2->sk_state == TCP_TIME_WAIT) {
 469                                 tw = inet_twsk(sk2);
 470                                 if (twsk_unique(sk, sk2, twp))
 471                                         break;
 472                         }
 473                         goto not_unique;
 474                 }
 475         }
 476
 477         /* Must record num and sport now. Otherwise we will see
 478          * in hash table socket with a funny identity.
 479          */
 480         inet->inet_num = lport;
 481         inet->inet_sport = htons(lport);
 482         sk->sk_hash = hash;
 483         WARN_ON(!sk_unhashed(sk));
 484         __sk_nulls_add_node_rcu(sk, &head->chain);
 485         if (tw) {
 486                 sk_nulls_del_node_init_rcu((struct sock *)tw);
 487                 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
 488         }
 489         spin_unlock(lock);
 490         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 491
 492         if (twp) {
 493                 *twp = tw;
 494         } else if (tw) {
 495                 /* Silly. Should hash-dance instead... */
 496                 inet_twsk_deschedule_put(tw);
 497         }
 498         return 0;
 499
 500 not_unique:
 501         spin_unlock(lock);
 502         return -EADDRNOTAVAIL;
 503 }
 504
 505 static u32 inet_sk_port_offset(const struct sock *sk)
 506 {
 507         const struct inet_sock *inet = inet_sk(sk);
 508
 509         return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
 510                                           inet->inet_daddr,
 511                                           inet->inet_dport);
 512 }
 513
 514 /* Searches for an exsiting socket in the ehash bucket list.
 515  * Returns true if found, false otherwise.
 516  */
 517 static bool inet_ehash_lookup_by_sk(struct sock *sk,
 518                                     struct hlist_nulls_head *list)
 519 {
 520         const __portpair ports = INET_COMBINED_PORTS(sk->sk_dport, sk->sk_num);
 521         const int sdif = sk->sk_bound_dev_if;
 522         const int dif = sk->sk_bound_dev_if;
 523         const struct hlist_nulls_node *node;
 524         struct net *net = sock_net(sk);
 525         struct sock *esk;
 526
 527         INET_ADDR_COOKIE(acookie, sk->sk_daddr, sk->sk_rcv_saddr);
 528
 529         sk_nulls_for_each_rcu(esk, node, list) {
 530                 if (esk->sk_hash != sk->sk_hash)
 531                         continue;
 532                 if (sk->sk_family == AF_INET) {
 533                         if (unlikely(INET_MATCH(esk, net, acookie,
 534                                                 sk->sk_daddr,
 535                                                 sk->sk_rcv_saddr,
 536                                                 ports, dif, sdif))) {
 537                                 return true;
 538                         }
 539                 }
 540 #if IS_ENABLED(CONFIG_IPV6)
 541                 else if (sk->sk_family == AF_INET6) {
 542                         if (unlikely(INET6_MATCH(esk, net,
 543                                                  &sk->sk_v6_daddr,
 544                                                  &sk->sk_v6_rcv_saddr,
 545                                                  ports, dif, sdif))) {
 546                                 return true;
 547                         }
 548                 }
 549 #endif
 550         }
 551         return false;
 552 }
 553
 554 /* Insert a socket into ehash, and eventually remove another one
 555  * (The another one can be a SYN_RECV or TIMEWAIT)
 556  * If an existing socket already exists, socket sk is not inserted,
 557  * and sets found_dup_sk parameter to true.
 558  */
 559 bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk)
 560 {
 561         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 562         struct hlist_nulls_head *list;
 563         struct inet_ehash_bucket *head;
 564         spinlock_t *lock;
 565         bool ret = true;
 566
 567         WARN_ON_ONCE(!sk_unhashed(sk));
 568
 569         sk->sk_hash = sk_ehashfn(sk);
 570         head = inet_ehash_bucket(hashinfo, sk->sk_hash);
 571         list = &head->chain;
 572         lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 573
 574         spin_lock(lock);
 575         if (osk) {
 576                 WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
 577                 ret = sk_nulls_del_node_init_rcu(osk);
 578         } else if (found_dup_sk) {
 579                 *found_dup_sk = inet_ehash_lookup_by_sk(sk, list);
 580                 if (*found_dup_sk)
 581                         ret = false;
 582         }
 583
 584         if (ret)
 585                 __sk_nulls_add_node_rcu(sk, list);
 586
 587         spin_unlock(lock);
 588
 589         return ret;
 590 }
 591
 592 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, bool *found_dup_sk)
 593 {
 594         bool ok = inet_ehash_insert(sk, osk, found_dup_sk);
 595
 596         if (ok) {
 597                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 598         } else {
 599                 percpu_counter_inc(sk->sk_prot->orphan_count);
 600                 inet_sk_set_state(sk, TCP_CLOSE);
 601                 sock_set_flag(sk, SOCK_DEAD);
 602                 inet_csk_destroy_sock(sk);
 603         }
 604         return ok;
 605 }
 606 EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
 607
 608 static int inet_reuseport_add_sock(struct sock *sk,
 609                                    struct inet_listen_hashbucket *ilb)
 610 {
 611         struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
 612         const struct hlist_nulls_node *node;
 613         struct sock *sk2;
 614         kuid_t uid = sock_i_uid(sk);
 615
 616         sk_nulls_for_each_rcu(sk2, node, &ilb->nulls_head) {
 617                 if (sk2 != sk &&
 618                     sk2->sk_family == sk->sk_family &&
 619                     ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
 620                     sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
 621                     inet_csk(sk2)->icsk_bind_hash == tb &&
 622                     sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
 623                     inet_rcv_saddr_equal(sk, sk2, false))
 624                         return reuseport_add_sock(sk, sk2,
 625                                                   inet_rcv_saddr_any(sk));
 626         }
 627
 628         return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
 629 }
 630
 631 int __inet_hash(struct sock *sk, struct sock *osk)
 632 {
 633         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 634         struct inet_listen_hashbucket *ilb;
 635         int err = 0;
 636
 637         if (sk->sk_state != TCP_LISTEN) {
 638                 inet_ehash_nolisten(sk, osk, NULL);
 639                 return 0;
 640         }
 641         WARN_ON(!sk_unhashed(sk));
 642         ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 643
 644         spin_lock(&ilb->lock);
 645         if (sk->sk_reuseport) {
 646                 err = inet_reuseport_add_sock(sk, ilb);
 647                 if (err)
 648                         goto unlock;
 649         }
 650         if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
 651                 sk->sk_family == AF_INET6)
 652                 __sk_nulls_add_node_tail_rcu(sk, &ilb->nulls_head);
 653         else
 654                 __sk_nulls_add_node_rcu(sk, &ilb->nulls_head);
 655         inet_hash2(hashinfo, sk);
 656         ilb->count++;
 657         sock_set_flag(sk, SOCK_RCU_FREE);
 658         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 659 unlock:
 660         spin_unlock(&ilb->lock);
 661
 662         return err;
 663 }
 664 EXPORT_SYMBOL(__inet_hash);
 665
 666 int inet_hash(struct sock *sk)
 667 {
 668         int err = 0;
 669
 670         if (sk->sk_state != TCP_CLOSE) {
 671                 local_bh_disable();
 672                 err = __inet_hash(sk, NULL);
 673                 local_bh_enable();
 674         }
 675
 676         return err;
 677 }
 678 EXPORT_SYMBOL_GPL(inet_hash);
 679
 680 void inet_unhash(struct sock *sk)
 681 {
 682         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 683         struct inet_listen_hashbucket *ilb = NULL;
 684         spinlock_t *lock;
 685
 686         if (sk_unhashed(sk))
 687                 return;
 688
 689         if (sk->sk_state == TCP_LISTEN) {
 690                 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 691                 lock = &ilb->lock;
 692         } else {
 693                 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 694         }
 695         spin_lock_bh(lock);
 696         if (sk_unhashed(sk))
 697                 goto unlock;
 698
 699         if (rcu_access_pointer(sk->sk_reuseport_cb))
 700                 reuseport_detach_sock(sk);
 701         if (ilb) {
 702                 inet_unhash2(hashinfo, sk);
 703                 ilb->count--;
 704         }
 705         __sk_nulls_del_node_init_rcu(sk);
 706         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 707 unlock:
 708         spin_unlock_bh(lock);
 709 }
 710 EXPORT_SYMBOL_GPL(inet_unhash);
 711
 712 /* RFC 6056 3.3.4.  Algorithm 4: Double-Hash Port Selection Algorithm
 713  * Note that we use 32bit integers (vs RFC 'short integers')
 714  * because 2^16 is not a multiple of num_ephemeral and this
 715  * property might be used by clever attacker.
 716  * RFC claims using TABLE_LENGTH=10 buckets gives an improvement,
 717  * we use 256 instead to really give more isolation and
 718  * privacy, this only consumes 1 KB of kernel memory.
 719  */
 720 #define INET_TABLE_PERTURB_SHIFT 8
 721 static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT];
 722
 723 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 724                 struct sock *sk, u32 port_offset,
 725                 int (*check_established)(struct inet_timewait_death_row *,
 726                         struct sock *, __u16, struct inet_timewait_sock **))
 727 {
 728         struct inet_hashinfo *hinfo = death_row->hashinfo;
 729         struct inet_timewait_sock *tw = NULL;
 730         struct inet_bind_hashbucket *head;
 731         int port = inet_sk(sk)->inet_num;
 732         struct net *net = sock_net(sk);
 733         struct inet_bind_bucket *tb;
 734         u32 remaining, offset;
 735         int ret, i, low, high;
 736         int l3mdev;
 737         u32 index;
 738
 739         if (port) {
 740                 head = &hinfo->bhash[inet_bhashfn(net, port,
 741                                                   hinfo->bhash_size)];
 742                 tb = inet_csk(sk)->icsk_bind_hash;
 743                 spin_lock_bh(&head->lock);
 744                 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
 745                         inet_ehash_nolisten(sk, NULL, NULL);
 746                         spin_unlock_bh(&head->lock);
 747                         return 0;
 748                 }
 749                 spin_unlock(&head->lock);
 750                 /* No definite answer... Walk to established hash table */
 751                 ret = check_established(death_row, sk, port, NULL);
 752                 local_bh_enable();
 753                 return ret;
 754         }
 755
 756         l3mdev = inet_sk_bound_l3mdev(sk);
 757
 758         inet_get_local_port_range(net, &low, &high);
 759         high++; /* [32768, 60999] -> [32768, 61000[ */
 760         remaining = high - low;
 761         if (likely(remaining > 1))
 762                 remaining &= ~1U;
 763
 764         net_get_random_once(table_perturb, sizeof(table_perturb));
 765         index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT);
 766
 767         offset = (READ_ONCE(table_perturb[index]) + port_offset) % remaining;
 768         /* In first pass we try ports of @low parity.
 769          * inet_csk_get_port() does the opposite choice.
 770          */
 771         offset &= ~1U;
 772 other_parity_scan:
 773         port = low + offset;
 774         for (i = 0; i < remaining; i += 2, port += 2) {
 775                 if (unlikely(port >= high))
 776                         port -= remaining;
 777                 if (inet_is_local_reserved_port(net, port))
 778                         continue;
 779                 head = &hinfo->bhash[inet_bhashfn(net, port,
 780                                                   hinfo->bhash_size)];
 781                 spin_lock_bh(&head->lock);
 782
 783                 /* Does not bother with rcv_saddr checks, because
 784                  * the established check is already unique enough.
 785                  */
 786                 inet_bind_bucket_for_each(tb, &head->chain) {
 787                         if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev &&
 788                             tb->port == port) {
 789                                 if (tb->fastreuse >= 0 ||
 790                                     tb->fastreuseport >= 0)
 791                                         goto next_port;
 792                                 WARN_ON(hlist_empty(&tb->owners));
 793                                 if (!check_established(death_row, sk,
 794                                                        port, &tw))
 795                                         goto ok;
 796                                 goto next_port;
 797                         }
 798                 }
 799
 800                 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
 801                                              net, head, port, l3mdev);
 802                 if (!tb) {
 803                         spin_unlock_bh(&head->lock);
 804                         return -ENOMEM;
 805                 }
 806                 tb->fastreuse = -1;
 807                 tb->fastreuseport = -1;
 808                 goto ok;
 809 next_port:
 810                 spin_unlock_bh(&head->lock);
 811                 cond_resched();
 812         }
 813
 814         offset++;
 815         if ((offset & 1) && remaining > 1)
 816                 goto other_parity_scan;
 817
 818         return -EADDRNOTAVAIL;
 819
 820 ok:
 821         /* If our first attempt found a candidate, skip next candidate
 822          * in 1/16 of cases to add some noise.
 823          */
 824         if (!i && !(prandom_u32() % 16))
 825                 i = 2;
 826         WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2);
 827
 828         /* Head lock still held and bh's disabled */
 829         inet_bind_hash(sk, tb, port);
 830         if (sk_unhashed(sk)) {
 831                 inet_sk(sk)->inet_sport = htons(port);
 832                 inet_ehash_nolisten(sk, (struct sock *)tw, NULL);
 833         }
 834         if (tw)
 835                 inet_twsk_bind_unhash(tw, hinfo);
 836         spin_unlock(&head->lock);
 837         if (tw)
 838                 inet_twsk_deschedule_put(tw);
 839         local_bh_enable();
 840         return 0;
 841 }
 842
 843 /*
 844  * Bind a port for a connect operation and hash it.
 845  */
 846 int inet_hash_connect(struct inet_timewait_death_row *death_row,
 847                       struct sock *sk)
 848 {
 849         u32 port_offset = 0;
 850
 851         if (!inet_sk(sk)->inet_num)
 852                 port_offset = inet_sk_port_offset(sk);
 853         return __inet_hash_connect(death_row, sk, port_offset,
 854                                    __inet_check_established);
 855 }
 856 EXPORT_SYMBOL_GPL(inet_hash_connect);
 857
 858 void inet_hashinfo_init(struct inet_hashinfo *h)
 859 {
 860         int i;
 861
 862         for (i = 0; i < INET_LHTABLE_SIZE; i++) {
 863                 spin_lock_init(&h->listening_hash[i].lock);
 864                 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].nulls_head,
 865                                       i + LISTENING_NULLS_BASE);
 866                 h->listening_hash[i].count = 0;
 867         }
 868
 869         h->lhash2 = NULL;
 870 }
 871 EXPORT_SYMBOL_GPL(inet_hashinfo_init);
 872
 873 static void init_hashinfo_lhash2(struct inet_hashinfo *h)
 874 {
 875         int i;
 876
 877         for (i = 0; i <= h->lhash2_mask; i++) {
 878                 spin_lock_init(&h->lhash2[i].lock);
 879                 INIT_HLIST_HEAD(&h->lhash2[i].head);
 880                 h->lhash2[i].count = 0;
 881         }
 882 }
 883
 884 void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
 885                                 unsigned long numentries, int scale,
 886                                 unsigned long low_limit,
 887                                 unsigned long high_limit)
 888 {
 889         h->lhash2 = alloc_large_system_hash(name,
 890                                             sizeof(*h->lhash2),
 891                                             numentries,
 892                                             scale,
 893                                             0,
 894                                             NULL,
 895                                             &h->lhash2_mask,
 896                                             low_limit,
 897                                             high_limit);
 898         init_hashinfo_lhash2(h);
 899 }
 900
 901 int inet_hashinfo2_init_mod(struct inet_hashinfo *h)
 902 {
 903         h->lhash2 = kmalloc_array(INET_LHTABLE_SIZE, sizeof(*h->lhash2), GFP_KERNEL);
 904         if (!h->lhash2)
 905                 return -ENOMEM;
 906
 907         h->lhash2_mask = INET_LHTABLE_SIZE - 1;
 908         /* INET_LHTABLE_SIZE must be a power of 2 */
 909         BUG_ON(INET_LHTABLE_SIZE & h->lhash2_mask);
 910
 911         init_hashinfo_lhash2(h);
 912         return 0;
 913 }
 914 EXPORT_SYMBOL_GPL(inet_hashinfo2_init_mod);
 915
 916 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
 917 {
 918         unsigned int locksz = sizeof(spinlock_t);
 919         unsigned int i, nblocks = 1;
 920
 921         if (locksz != 0) {
 922                 /* allocate 2 cache lines or at least one spinlock per cpu */
 923                 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
 924                 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
 925
 926                 /* no more locks than number of hash buckets */
 927                 nblocks = min(nblocks, hashinfo->ehash_mask + 1);
 928
 929                 hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL);
 930                 if (!hashinfo->ehash_locks)
 931                         return -ENOMEM;
 932
 933                 for (i = 0; i < nblocks; i++)
 934                         spin_lock_init(&hashinfo->ehash_locks[i]);
 935         }
 936         hashinfo->ehash_locks_mask = nblocks - 1;
 937         return 0;
 938 }
 939 EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);