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 score = sk->sk_bound_dev_if ? 2 : 1; 246 247 if (sk->sk_family == PF_INET) 248 score++; 249 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id()) 250 score++; 251 } 252 return score; 253 } 254 255 static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk, 256 struct sk_buff *skb, int doff, 257 __be32 saddr, __be16 sport, 258 __be32 daddr, unsigned short hnum) 259 { 260 struct sock *reuse_sk = NULL; 261 u32 phash; 262 263 if (sk->sk_reuseport) { 264 phash = inet_ehashfn(net, daddr, hnum, saddr, sport); 265 reuse_sk = reuseport_select_sock(sk, phash, skb, doff); 266 } 267 return reuse_sk; 268 } 269 270 /* 271 * Here are some nice properties to exploit here. The BSD API 272 * does not allow a listening sock to specify the remote port nor the 273 * remote address for the connection. So always assume those are both 274 * wildcarded during the search since they can never be otherwise. 275 */ 276 277 /* called with rcu_read_lock() : No refcount taken on the socket */ 278 static struct sock *inet_lhash2_lookup(struct net *net, 279 struct inet_listen_hashbucket *ilb2, 280 struct sk_buff *skb, int doff, 281 const __be32 saddr, __be16 sport, 282 const __be32 daddr, const unsigned short hnum, 283 const int dif, const int sdif) 284 { 285 struct inet_connection_sock *icsk; 286 struct sock *sk, *result = NULL; 287 int score, hiscore = 0; 288 289 inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) { 290 sk = (struct sock *)icsk; 291 score = compute_score(sk, net, hnum, daddr, dif, sdif); 292 if (score > hiscore) { 293 result = lookup_reuseport(net, sk, skb, doff, 294 saddr, sport, daddr, hnum); 295 if (result) 296 return result; 297 298 result = sk; 299 hiscore = score; 300 } 301 } 302 303 return result; 304 } 305 306 static inline struct sock *inet_lookup_run_bpf(struct net *net, 307 struct inet_hashinfo *hashinfo, 308 struct sk_buff *skb, int doff, 309 __be32 saddr, __be16 sport, 310 __be32 daddr, u16 hnum, const int dif) 311 { 312 struct sock *sk, *reuse_sk; 313 bool no_reuseport; 314 315 if (hashinfo != &tcp_hashinfo) 316 return NULL; /* only TCP is supported */ 317 318 no_reuseport = bpf_sk_lookup_run_v4(net, IPPROTO_TCP, saddr, sport, 319 daddr, hnum, dif, &sk); 320 if (no_reuseport || IS_ERR_OR_NULL(sk)) 321 return sk; 322 323 reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum); 324 if (reuse_sk) 325 sk = reuse_sk; 326 return sk; 327 } 328 329 struct sock *__inet_lookup_listener(struct net *net, 330 struct inet_hashinfo *hashinfo, 331 struct sk_buff *skb, int doff, 332 const __be32 saddr, __be16 sport, 333 const __be32 daddr, const unsigned short hnum, 334 const int dif, const int sdif) 335 { 336 struct inet_listen_hashbucket *ilb2; 337 struct sock *result = NULL; 338 unsigned int hash2; 339 340 /* Lookup redirect from BPF */ 341 if (static_branch_unlikely(&bpf_sk_lookup_enabled)) { 342 result = inet_lookup_run_bpf(net, hashinfo, skb, doff, 343 saddr, sport, daddr, hnum, dif); 344 if (result) 345 goto done; 346 } 347 348 hash2 = ipv4_portaddr_hash(net, daddr, hnum); 349 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 350 351 result = inet_lhash2_lookup(net, ilb2, skb, doff, 352 saddr, sport, daddr, hnum, 353 dif, sdif); 354 if (result) 355 goto done; 356 357 /* Lookup lhash2 with INADDR_ANY */ 358 hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum); 359 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 360 361 result = inet_lhash2_lookup(net, ilb2, skb, doff, 362 saddr, sport, htonl(INADDR_ANY), hnum, 363 dif, sdif); 364 done: 365 if (IS_ERR(result)) 366 return NULL; 367 return result; 368 } 369 EXPORT_SYMBOL_GPL(__inet_lookup_listener); 370 371 /* All sockets share common refcount, but have different destructors */ 372 void sock_gen_put(struct sock *sk) 373 { 374 if (!refcount_dec_and_test(&sk->sk_refcnt)) 375 return; 376 377 if (sk->sk_state == TCP_TIME_WAIT) 378 inet_twsk_free(inet_twsk(sk)); 379 else if (sk->sk_state == TCP_NEW_SYN_RECV) 380 reqsk_free(inet_reqsk(sk)); 381 else 382 sk_free(sk); 383 } 384 EXPORT_SYMBOL_GPL(sock_gen_put); 385 386 void sock_edemux(struct sk_buff *skb) 387 { 388 sock_gen_put(skb->sk); 389 } 390 EXPORT_SYMBOL(sock_edemux); 391 392 struct sock *__inet_lookup_established(struct net *net, 393 struct inet_hashinfo *hashinfo, 394 const __be32 saddr, const __be16 sport, 395 const __be32 daddr, const u16 hnum, 396 const int dif, const int sdif) 397 { 398 INET_ADDR_COOKIE(acookie, saddr, daddr); 399 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 400 struct sock *sk; 401 const struct hlist_nulls_node *node; 402 /* Optimize here for direct hit, only listening connections can 403 * have wildcards anyways. 404 */ 405 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport); 406 unsigned int slot = hash & hashinfo->ehash_mask; 407 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 408 409 begin: 410 sk_nulls_for_each_rcu(sk, node, &head->chain) { 411 if (sk->sk_hash != hash) 412 continue; 413 if (likely(INET_MATCH(sk, net, acookie, 414 saddr, daddr, ports, dif, sdif))) { 415 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) 416 goto out; 417 if (unlikely(!INET_MATCH(sk, net, acookie, 418 saddr, daddr, ports, 419 dif, sdif))) { 420 sock_gen_put(sk); 421 goto begin; 422 } 423 goto found; 424 } 425 } 426 /* 427 * if the nulls value we got at the end of this lookup is 428 * not the expected one, we must restart lookup. 429 * We probably met an item that was moved to another chain. 430 */ 431 if (get_nulls_value(node) != slot) 432 goto begin; 433 out: 434 sk = NULL; 435 found: 436 return sk; 437 } 438 EXPORT_SYMBOL_GPL(__inet_lookup_established); 439 440 /* called with local bh disabled */ 441 static int __inet_check_established(struct inet_timewait_death_row *death_row, 442 struct sock *sk, __u16 lport, 443 struct inet_timewait_sock **twp) 444 { 445 struct inet_hashinfo *hinfo = death_row->hashinfo; 446 struct inet_sock *inet = inet_sk(sk); 447 __be32 daddr = inet->inet_rcv_saddr; 448 __be32 saddr = inet->inet_daddr; 449 int dif = sk->sk_bound_dev_if; 450 struct net *net = sock_net(sk); 451 int sdif = l3mdev_master_ifindex_by_index(net, dif); 452 INET_ADDR_COOKIE(acookie, saddr, daddr); 453 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 454 unsigned int hash = inet_ehashfn(net, daddr, lport, 455 saddr, inet->inet_dport); 456 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 457 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 458 struct sock *sk2; 459 const struct hlist_nulls_node *node; 460 struct inet_timewait_sock *tw = NULL; 461 462 spin_lock(lock); 463 464 sk_nulls_for_each(sk2, node, &head->chain) { 465 if (sk2->sk_hash != hash) 466 continue; 467 468 if (likely(INET_MATCH(sk2, net, acookie, 469 saddr, daddr, ports, dif, sdif))) { 470 if (sk2->sk_state == TCP_TIME_WAIT) { 471 tw = inet_twsk(sk2); 472 if (twsk_unique(sk, sk2, twp)) 473 break; 474 } 475 goto not_unique; 476 } 477 } 478 479 /* Must record num and sport now. Otherwise we will see 480 * in hash table socket with a funny identity. 481 */ 482 inet->inet_num = lport; 483 inet->inet_sport = htons(lport); 484 sk->sk_hash = hash; 485 WARN_ON(!sk_unhashed(sk)); 486 __sk_nulls_add_node_rcu(sk, &head->chain); 487 if (tw) { 488 sk_nulls_del_node_init_rcu((struct sock *)tw); 489 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 490 } 491 spin_unlock(lock); 492 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 493 494 if (twp) { 495 *twp = tw; 496 } else if (tw) { 497 /* Silly. Should hash-dance instead... */ 498 inet_twsk_deschedule_put(tw); 499 } 500 return 0; 501 502 not_unique: 503 spin_unlock(lock); 504 return -EADDRNOTAVAIL; 505 } 506 507 static u32 inet_sk_port_offset(const struct sock *sk) 508 { 509 const struct inet_sock *inet = inet_sk(sk); 510 511 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr, 512 inet->inet_daddr, 513 inet->inet_dport); 514 } 515 516 /* Searches for an exsiting socket in the ehash bucket list. 517 * Returns true if found, false otherwise. 518 */ 519 static bool inet_ehash_lookup_by_sk(struct sock *sk, 520 struct hlist_nulls_head *list) 521 { 522 const __portpair ports = INET_COMBINED_PORTS(sk->sk_dport, sk->sk_num); 523 const int sdif = sk->sk_bound_dev_if; 524 const int dif = sk->sk_bound_dev_if; 525 const struct hlist_nulls_node *node; 526 struct net *net = sock_net(sk); 527 struct sock *esk; 528 529 INET_ADDR_COOKIE(acookie, sk->sk_daddr, sk->sk_rcv_saddr); 530 531 sk_nulls_for_each_rcu(esk, node, list) { 532 if (esk->sk_hash != sk->sk_hash) 533 continue; 534 if (sk->sk_family == AF_INET) { 535 if (unlikely(INET_MATCH(esk, net, acookie, 536 sk->sk_daddr, 537 sk->sk_rcv_saddr, 538 ports, dif, sdif))) { 539 return true; 540 } 541 } 542 #if IS_ENABLED(CONFIG_IPV6) 543 else if (sk->sk_family == AF_INET6) { 544 if (unlikely(INET6_MATCH(esk, net, 545 &sk->sk_v6_daddr, 546 &sk->sk_v6_rcv_saddr, 547 ports, dif, sdif))) { 548 return true; 549 } 550 } 551 #endif 552 } 553 return false; 554 } 555 556 /* Insert a socket into ehash, and eventually remove another one 557 * (The another one can be a SYN_RECV or TIMEWAIT) 558 * If an existing socket already exists, socket sk is not inserted, 559 * and sets found_dup_sk parameter to true. 560 */ 561 bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk) 562 { 563 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 564 struct hlist_nulls_head *list; 565 struct inet_ehash_bucket *head; 566 spinlock_t *lock; 567 bool ret = true; 568 569 WARN_ON_ONCE(!sk_unhashed(sk)); 570 571 sk->sk_hash = sk_ehashfn(sk); 572 head = inet_ehash_bucket(hashinfo, sk->sk_hash); 573 list = &head->chain; 574 lock = inet_ehash_lockp(hashinfo, sk->sk_hash); 575 576 spin_lock(lock); 577 if (osk) { 578 WARN_ON_ONCE(sk->sk_hash != osk->sk_hash); 579 ret = sk_nulls_del_node_init_rcu(osk); 580 } else if (found_dup_sk) { 581 *found_dup_sk = inet_ehash_lookup_by_sk(sk, list); 582 if (*found_dup_sk) 583 ret = false; 584 } 585 586 if (ret) 587 __sk_nulls_add_node_rcu(sk, list); 588 589 spin_unlock(lock); 590 591 return ret; 592 } 593 594 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, bool *found_dup_sk) 595 { 596 bool ok = inet_ehash_insert(sk, osk, found_dup_sk); 597 598 if (ok) { 599 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 600 } else { 601 this_cpu_inc(*sk->sk_prot->orphan_count); 602 inet_sk_set_state(sk, TCP_CLOSE); 603 sock_set_flag(sk, SOCK_DEAD); 604 inet_csk_destroy_sock(sk); 605 } 606 return ok; 607 } 608 EXPORT_SYMBOL_GPL(inet_ehash_nolisten); 609 610 static int inet_reuseport_add_sock(struct sock *sk, 611 struct inet_listen_hashbucket *ilb) 612 { 613 struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash; 614 const struct hlist_nulls_node *node; 615 struct sock *sk2; 616 kuid_t uid = sock_i_uid(sk); 617 618 sk_nulls_for_each_rcu(sk2, node, &ilb->nulls_head) { 619 if (sk2 != sk && 620 sk2->sk_family == sk->sk_family && 621 ipv6_only_sock(sk2) == ipv6_only_sock(sk) && 622 sk2->sk_bound_dev_if == sk->sk_bound_dev_if && 623 inet_csk(sk2)->icsk_bind_hash == tb && 624 sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) && 625 inet_rcv_saddr_equal(sk, sk2, false)) 626 return reuseport_add_sock(sk, sk2, 627 inet_rcv_saddr_any(sk)); 628 } 629 630 return reuseport_alloc(sk, inet_rcv_saddr_any(sk)); 631 } 632 633 int __inet_hash(struct sock *sk, struct sock *osk) 634 { 635 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 636 struct inet_listen_hashbucket *ilb; 637 int err = 0; 638 639 if (sk->sk_state != TCP_LISTEN) { 640 inet_ehash_nolisten(sk, osk, NULL); 641 return 0; 642 } 643 WARN_ON(!sk_unhashed(sk)); 644 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; 645 646 spin_lock(&ilb->lock); 647 if (sk->sk_reuseport) { 648 err = inet_reuseport_add_sock(sk, ilb); 649 if (err) 650 goto unlock; 651 } 652 if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport && 653 sk->sk_family == AF_INET6) 654 __sk_nulls_add_node_tail_rcu(sk, &ilb->nulls_head); 655 else 656 __sk_nulls_add_node_rcu(sk, &ilb->nulls_head); 657 inet_hash2(hashinfo, sk); 658 ilb->count++; 659 sock_set_flag(sk, SOCK_RCU_FREE); 660 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 661 unlock: 662 spin_unlock(&ilb->lock); 663 664 return err; 665 } 666 EXPORT_SYMBOL(__inet_hash); 667 668 int inet_hash(struct sock *sk) 669 { 670 int err = 0; 671 672 if (sk->sk_state != TCP_CLOSE) { 673 local_bh_disable(); 674 err = __inet_hash(sk, NULL); 675 local_bh_enable(); 676 } 677 678 return err; 679 } 680 EXPORT_SYMBOL_GPL(inet_hash); 681 682 void inet_unhash(struct sock *sk) 683 { 684 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 685 struct inet_listen_hashbucket *ilb = NULL; 686 spinlock_t *lock; 687 688 if (sk_unhashed(sk)) 689 return; 690 691 if (sk->sk_state == TCP_LISTEN) { 692 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; 693 lock = &ilb->lock; 694 } else { 695 lock = inet_ehash_lockp(hashinfo, sk->sk_hash); 696 } 697 spin_lock_bh(lock); 698 if (sk_unhashed(sk)) 699 goto unlock; 700 701 if (rcu_access_pointer(sk->sk_reuseport_cb)) 702 reuseport_stop_listen_sock(sk); 703 if (ilb) { 704 inet_unhash2(hashinfo, sk); 705 ilb->count--; 706 } 707 __sk_nulls_del_node_init_rcu(sk); 708 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 709 unlock: 710 spin_unlock_bh(lock); 711 } 712 EXPORT_SYMBOL_GPL(inet_unhash); 713 714 /* RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm 715 * Note that we use 32bit integers (vs RFC 'short integers') 716 * because 2^16 is not a multiple of num_ephemeral and this 717 * property might be used by clever attacker. 718 * RFC claims using TABLE_LENGTH=10 buckets gives an improvement, 719 * we use 256 instead to really give more isolation and 720 * privacy, this only consumes 1 KB of kernel memory. 721 */ 722 #define INET_TABLE_PERTURB_SHIFT 8 723 static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT]; 724 725 int __inet_hash_connect(struct inet_timewait_death_row *death_row, 726 struct sock *sk, u32 port_offset, 727 int (*check_established)(struct inet_timewait_death_row *, 728 struct sock *, __u16, struct inet_timewait_sock **)) 729 { 730 struct inet_hashinfo *hinfo = death_row->hashinfo; 731 struct inet_timewait_sock *tw = NULL; 732 struct inet_bind_hashbucket *head; 733 int port = inet_sk(sk)->inet_num; 734 struct net *net = sock_net(sk); 735 struct inet_bind_bucket *tb; 736 u32 remaining, offset; 737 int ret, i, low, high; 738 int l3mdev; 739 u32 index; 740 741 if (port) { 742 head = &hinfo->bhash[inet_bhashfn(net, port, 743 hinfo->bhash_size)]; 744 tb = inet_csk(sk)->icsk_bind_hash; 745 spin_lock_bh(&head->lock); 746 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { 747 inet_ehash_nolisten(sk, NULL, NULL); 748 spin_unlock_bh(&head->lock); 749 return 0; 750 } 751 spin_unlock(&head->lock); 752 /* No definite answer... Walk to established hash table */ 753 ret = check_established(death_row, sk, port, NULL); 754 local_bh_enable(); 755 return ret; 756 } 757 758 l3mdev = inet_sk_bound_l3mdev(sk); 759 760 inet_get_local_port_range(net, &low, &high); 761 high++; /* [32768, 60999] -> [32768, 61000[ */ 762 remaining = high - low; 763 if (likely(remaining > 1)) 764 remaining &= ~1U; 765 766 net_get_random_once(table_perturb, sizeof(table_perturb)); 767 index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT); 768 769 offset = (READ_ONCE(table_perturb[index]) + port_offset) % remaining; 770 /* In first pass we try ports of @low parity. 771 * inet_csk_get_port() does the opposite choice. 772 */ 773 offset &= ~1U; 774 other_parity_scan: 775 port = low + offset; 776 for (i = 0; i < remaining; i += 2, port += 2) { 777 if (unlikely(port >= high)) 778 port -= remaining; 779 if (inet_is_local_reserved_port(net, port)) 780 continue; 781 head = &hinfo->bhash[inet_bhashfn(net, port, 782 hinfo->bhash_size)]; 783 spin_lock_bh(&head->lock); 784 785 /* Does not bother with rcv_saddr checks, because 786 * the established check is already unique enough. 787 */ 788 inet_bind_bucket_for_each(tb, &head->chain) { 789 if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev && 790 tb->port == port) { 791 if (tb->fastreuse >= 0 || 792 tb->fastreuseport >= 0) 793 goto next_port; 794 WARN_ON(hlist_empty(&tb->owners)); 795 if (!check_established(death_row, sk, 796 port, &tw)) 797 goto ok; 798 goto next_port; 799 } 800 } 801 802 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, 803 net, head, port, l3mdev); 804 if (!tb) { 805 spin_unlock_bh(&head->lock); 806 return -ENOMEM; 807 } 808 tb->fastreuse = -1; 809 tb->fastreuseport = -1; 810 goto ok; 811 next_port: 812 spin_unlock_bh(&head->lock); 813 cond_resched(); 814 } 815 816 offset++; 817 if ((offset & 1) && remaining > 1) 818 goto other_parity_scan; 819 820 return -EADDRNOTAVAIL; 821 822 ok: 823 /* If our first attempt found a candidate, skip next candidate 824 * in 1/16 of cases to add some noise. 825 */ 826 if (!i && !(prandom_u32() % 16)) 827 i = 2; 828 WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2); 829 830 /* Head lock still held and bh's disabled */ 831 inet_bind_hash(sk, tb, port); 832 if (sk_unhashed(sk)) { 833 inet_sk(sk)->inet_sport = htons(port); 834 inet_ehash_nolisten(sk, (struct sock *)tw, NULL); 835 } 836 if (tw) 837 inet_twsk_bind_unhash(tw, hinfo); 838 spin_unlock(&head->lock); 839 if (tw) 840 inet_twsk_deschedule_put(tw); 841 local_bh_enable(); 842 return 0; 843 } 844 845 /* 846 * Bind a port for a connect operation and hash it. 847 */ 848 int inet_hash_connect(struct inet_timewait_death_row *death_row, 849 struct sock *sk) 850 { 851 u32 port_offset = 0; 852 853 if (!inet_sk(sk)->inet_num) 854 port_offset = inet_sk_port_offset(sk); 855 return __inet_hash_connect(death_row, sk, port_offset, 856 __inet_check_established); 857 } 858 EXPORT_SYMBOL_GPL(inet_hash_connect); 859 860 void inet_hashinfo_init(struct inet_hashinfo *h) 861 { 862 int i; 863 864 for (i = 0; i < INET_LHTABLE_SIZE; i++) { 865 spin_lock_init(&h->listening_hash[i].lock); 866 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].nulls_head, 867 i + LISTENING_NULLS_BASE); 868 h->listening_hash[i].count = 0; 869 } 870 871 h->lhash2 = NULL; 872 } 873 EXPORT_SYMBOL_GPL(inet_hashinfo_init); 874 875 static void init_hashinfo_lhash2(struct inet_hashinfo *h) 876 { 877 int i; 878 879 for (i = 0; i <= h->lhash2_mask; i++) { 880 spin_lock_init(&h->lhash2[i].lock); 881 INIT_HLIST_HEAD(&h->lhash2[i].head); 882 h->lhash2[i].count = 0; 883 } 884 } 885 886 void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name, 887 unsigned long numentries, int scale, 888 unsigned long low_limit, 889 unsigned long high_limit) 890 { 891 h->lhash2 = alloc_large_system_hash(name, 892 sizeof(*h->lhash2), 893 numentries, 894 scale, 895 0, 896 NULL, 897 &h->lhash2_mask, 898 low_limit, 899 high_limit); 900 init_hashinfo_lhash2(h); 901 } 902 903 int inet_hashinfo2_init_mod(struct inet_hashinfo *h) 904 { 905 h->lhash2 = kmalloc_array(INET_LHTABLE_SIZE, sizeof(*h->lhash2), GFP_KERNEL); 906 if (!h->lhash2) 907 return -ENOMEM; 908 909 h->lhash2_mask = INET_LHTABLE_SIZE - 1; 910 /* INET_LHTABLE_SIZE must be a power of 2 */ 911 BUG_ON(INET_LHTABLE_SIZE & h->lhash2_mask); 912 913 init_hashinfo_lhash2(h); 914 return 0; 915 } 916 EXPORT_SYMBOL_GPL(inet_hashinfo2_init_mod); 917 918 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) 919 { 920 unsigned int locksz = sizeof(spinlock_t); 921 unsigned int i, nblocks = 1; 922 923 if (locksz != 0) { 924 /* allocate 2 cache lines or at least one spinlock per cpu */ 925 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U); 926 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus()); 927 928 /* no more locks than number of hash buckets */ 929 nblocks = min(nblocks, hashinfo->ehash_mask + 1); 930 931 hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL); 932 if (!hashinfo->ehash_locks) 933 return -ENOMEM; 934 935 for (i = 0; i < nblocks; i++) 936 spin_lock_init(&hashinfo->ehash_locks[i]); 937 } 938 hashinfo->ehash_locks_mask = nblocks - 1; 939 return 0; 940 } 941 EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc); 942