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 struct inet_bind2_bucket *inet_bind2_bucket_create(struct kmem_cache *cachep, 85 struct net *net, 86 struct inet_bind2_hashbucket *head, 87 const unsigned short port, 88 int l3mdev, 89 const struct sock *sk) 90 { 91 struct inet_bind2_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC); 92 93 if (tb) { 94 write_pnet(&tb->ib_net, net); 95 tb->l3mdev = l3mdev; 96 tb->port = port; 97 #if IS_ENABLED(CONFIG_IPV6) 98 if (sk->sk_family == AF_INET6) 99 tb->v6_rcv_saddr = sk->sk_v6_rcv_saddr; 100 else 101 #endif 102 tb->rcv_saddr = sk->sk_rcv_saddr; 103 INIT_HLIST_HEAD(&tb->owners); 104 hlist_add_head(&tb->node, &head->chain); 105 } 106 return tb; 107 } 108 109 static bool bind2_bucket_addr_match(struct inet_bind2_bucket *tb2, struct sock *sk) 110 { 111 #if IS_ENABLED(CONFIG_IPV6) 112 if (sk->sk_family == AF_INET6) 113 return ipv6_addr_equal(&tb2->v6_rcv_saddr, 114 &sk->sk_v6_rcv_saddr); 115 #endif 116 return tb2->rcv_saddr == sk->sk_rcv_saddr; 117 } 118 119 /* 120 * Caller must hold hashbucket lock for this tb with local BH disabled 121 */ 122 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb) 123 { 124 if (hlist_empty(&tb->owners)) { 125 __hlist_del(&tb->node); 126 kmem_cache_free(cachep, tb); 127 } 128 } 129 130 /* Caller must hold the lock for the corresponding hashbucket in the bhash table 131 * with local BH disabled 132 */ 133 void inet_bind2_bucket_destroy(struct kmem_cache *cachep, struct inet_bind2_bucket *tb) 134 { 135 if (hlist_empty(&tb->owners)) { 136 __hlist_del(&tb->node); 137 kmem_cache_free(cachep, tb); 138 } 139 } 140 141 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, 142 struct inet_bind2_bucket *tb2, const unsigned short snum) 143 { 144 inet_sk(sk)->inet_num = snum; 145 sk_add_bind_node(sk, &tb->owners); 146 inet_csk(sk)->icsk_bind_hash = tb; 147 sk_add_bind2_node(sk, &tb2->owners); 148 inet_csk(sk)->icsk_bind2_hash = tb2; 149 } 150 151 /* 152 * Get rid of any references to a local port held by the given sock. 153 */ 154 static void __inet_put_port(struct sock *sk) 155 { 156 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 157 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num, 158 hashinfo->bhash_size); 159 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash]; 160 struct inet_bind2_bucket *tb2; 161 struct inet_bind_bucket *tb; 162 163 spin_lock(&head->lock); 164 tb = inet_csk(sk)->icsk_bind_hash; 165 __sk_del_bind_node(sk); 166 inet_csk(sk)->icsk_bind_hash = NULL; 167 inet_sk(sk)->inet_num = 0; 168 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); 169 170 if (inet_csk(sk)->icsk_bind2_hash) { 171 tb2 = inet_csk(sk)->icsk_bind2_hash; 172 __sk_del_bind2_node(sk); 173 inet_csk(sk)->icsk_bind2_hash = NULL; 174 inet_bind2_bucket_destroy(hashinfo->bind2_bucket_cachep, tb2); 175 } 176 spin_unlock(&head->lock); 177 } 178 179 void inet_put_port(struct sock *sk) 180 { 181 local_bh_disable(); 182 __inet_put_port(sk); 183 local_bh_enable(); 184 } 185 EXPORT_SYMBOL(inet_put_port); 186 187 int __inet_inherit_port(const struct sock *sk, struct sock *child) 188 { 189 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo; 190 unsigned short port = inet_sk(child)->inet_num; 191 const int bhash = inet_bhashfn(sock_net(sk), port, 192 table->bhash_size); 193 struct inet_bind_hashbucket *head = &table->bhash[bhash]; 194 struct inet_bind2_hashbucket *head_bhash2; 195 bool created_inet_bind_bucket = false; 196 struct net *net = sock_net(sk); 197 struct inet_bind2_bucket *tb2; 198 struct inet_bind_bucket *tb; 199 int l3mdev; 200 201 spin_lock(&head->lock); 202 tb = inet_csk(sk)->icsk_bind_hash; 203 tb2 = inet_csk(sk)->icsk_bind2_hash; 204 if (unlikely(!tb || !tb2)) { 205 spin_unlock(&head->lock); 206 return -ENOENT; 207 } 208 if (tb->port != port) { 209 l3mdev = inet_sk_bound_l3mdev(sk); 210 211 /* NOTE: using tproxy and redirecting skbs to a proxy 212 * on a different listener port breaks the assumption 213 * that the listener socket's icsk_bind_hash is the same 214 * as that of the child socket. We have to look up or 215 * create a new bind bucket for the child here. */ 216 inet_bind_bucket_for_each(tb, &head->chain) { 217 if (check_bind_bucket_match(tb, net, port, l3mdev)) 218 break; 219 } 220 if (!tb) { 221 tb = inet_bind_bucket_create(table->bind_bucket_cachep, 222 net, head, port, l3mdev); 223 if (!tb) { 224 spin_unlock(&head->lock); 225 return -ENOMEM; 226 } 227 created_inet_bind_bucket = true; 228 } 229 inet_csk_update_fastreuse(tb, child); 230 231 goto bhash2_find; 232 } else if (!bind2_bucket_addr_match(tb2, child)) { 233 l3mdev = inet_sk_bound_l3mdev(sk); 234 235 bhash2_find: 236 tb2 = inet_bind2_bucket_find(table, net, port, l3mdev, child, 237 &head_bhash2); 238 if (!tb2) { 239 tb2 = inet_bind2_bucket_create(table->bind2_bucket_cachep, 240 net, head_bhash2, port, 241 l3mdev, child); 242 if (!tb2) 243 goto error; 244 } 245 } 246 inet_bind_hash(child, tb, tb2, port); 247 spin_unlock(&head->lock); 248 249 return 0; 250 251 error: 252 if (created_inet_bind_bucket) 253 inet_bind_bucket_destroy(table->bind_bucket_cachep, tb); 254 spin_unlock(&head->lock); 255 return -ENOMEM; 256 } 257 EXPORT_SYMBOL_GPL(__inet_inherit_port); 258 259 static struct inet_listen_hashbucket * 260 inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk) 261 { 262 u32 hash; 263 264 #if IS_ENABLED(CONFIG_IPV6) 265 if (sk->sk_family == AF_INET6) 266 hash = ipv6_portaddr_hash(sock_net(sk), 267 &sk->sk_v6_rcv_saddr, 268 inet_sk(sk)->inet_num); 269 else 270 #endif 271 hash = ipv4_portaddr_hash(sock_net(sk), 272 inet_sk(sk)->inet_rcv_saddr, 273 inet_sk(sk)->inet_num); 274 return inet_lhash2_bucket(h, hash); 275 } 276 277 static inline int compute_score(struct sock *sk, struct net *net, 278 const unsigned short hnum, const __be32 daddr, 279 const int dif, const int sdif) 280 { 281 int score = -1; 282 283 if (net_eq(sock_net(sk), net) && sk->sk_num == hnum && 284 !ipv6_only_sock(sk)) { 285 if (sk->sk_rcv_saddr != daddr) 286 return -1; 287 288 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif)) 289 return -1; 290 score = sk->sk_bound_dev_if ? 2 : 1; 291 292 if (sk->sk_family == PF_INET) 293 score++; 294 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id()) 295 score++; 296 } 297 return score; 298 } 299 300 static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk, 301 struct sk_buff *skb, int doff, 302 __be32 saddr, __be16 sport, 303 __be32 daddr, unsigned short hnum) 304 { 305 struct sock *reuse_sk = NULL; 306 u32 phash; 307 308 if (sk->sk_reuseport) { 309 phash = inet_ehashfn(net, daddr, hnum, saddr, sport); 310 reuse_sk = reuseport_select_sock(sk, phash, skb, doff); 311 } 312 return reuse_sk; 313 } 314 315 /* 316 * Here are some nice properties to exploit here. The BSD API 317 * does not allow a listening sock to specify the remote port nor the 318 * remote address for the connection. So always assume those are both 319 * wildcarded during the search since they can never be otherwise. 320 */ 321 322 /* called with rcu_read_lock() : No refcount taken on the socket */ 323 static struct sock *inet_lhash2_lookup(struct net *net, 324 struct inet_listen_hashbucket *ilb2, 325 struct sk_buff *skb, int doff, 326 const __be32 saddr, __be16 sport, 327 const __be32 daddr, const unsigned short hnum, 328 const int dif, const int sdif) 329 { 330 struct sock *sk, *result = NULL; 331 struct hlist_nulls_node *node; 332 int score, hiscore = 0; 333 334 sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) { 335 score = compute_score(sk, net, hnum, daddr, dif, sdif); 336 if (score > hiscore) { 337 result = lookup_reuseport(net, sk, skb, doff, 338 saddr, sport, daddr, hnum); 339 if (result) 340 return result; 341 342 result = sk; 343 hiscore = score; 344 } 345 } 346 347 return result; 348 } 349 350 static inline struct sock *inet_lookup_run_bpf(struct net *net, 351 struct inet_hashinfo *hashinfo, 352 struct sk_buff *skb, int doff, 353 __be32 saddr, __be16 sport, 354 __be32 daddr, u16 hnum, const int dif) 355 { 356 struct sock *sk, *reuse_sk; 357 bool no_reuseport; 358 359 if (hashinfo != &tcp_hashinfo) 360 return NULL; /* only TCP is supported */ 361 362 no_reuseport = bpf_sk_lookup_run_v4(net, IPPROTO_TCP, saddr, sport, 363 daddr, hnum, dif, &sk); 364 if (no_reuseport || IS_ERR_OR_NULL(sk)) 365 return sk; 366 367 reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum); 368 if (reuse_sk) 369 sk = reuse_sk; 370 return sk; 371 } 372 373 struct sock *__inet_lookup_listener(struct net *net, 374 struct inet_hashinfo *hashinfo, 375 struct sk_buff *skb, int doff, 376 const __be32 saddr, __be16 sport, 377 const __be32 daddr, const unsigned short hnum, 378 const int dif, const int sdif) 379 { 380 struct inet_listen_hashbucket *ilb2; 381 struct sock *result = NULL; 382 unsigned int hash2; 383 384 /* Lookup redirect from BPF */ 385 if (static_branch_unlikely(&bpf_sk_lookup_enabled)) { 386 result = inet_lookup_run_bpf(net, hashinfo, skb, doff, 387 saddr, sport, daddr, hnum, dif); 388 if (result) 389 goto done; 390 } 391 392 hash2 = ipv4_portaddr_hash(net, daddr, hnum); 393 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 394 395 result = inet_lhash2_lookup(net, ilb2, skb, doff, 396 saddr, sport, daddr, hnum, 397 dif, sdif); 398 if (result) 399 goto done; 400 401 /* Lookup lhash2 with INADDR_ANY */ 402 hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum); 403 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 404 405 result = inet_lhash2_lookup(net, ilb2, skb, doff, 406 saddr, sport, htonl(INADDR_ANY), hnum, 407 dif, sdif); 408 done: 409 if (IS_ERR(result)) 410 return NULL; 411 return result; 412 } 413 EXPORT_SYMBOL_GPL(__inet_lookup_listener); 414 415 /* All sockets share common refcount, but have different destructors */ 416 void sock_gen_put(struct sock *sk) 417 { 418 if (!refcount_dec_and_test(&sk->sk_refcnt)) 419 return; 420 421 if (sk->sk_state == TCP_TIME_WAIT) 422 inet_twsk_free(inet_twsk(sk)); 423 else if (sk->sk_state == TCP_NEW_SYN_RECV) 424 reqsk_free(inet_reqsk(sk)); 425 else 426 sk_free(sk); 427 } 428 EXPORT_SYMBOL_GPL(sock_gen_put); 429 430 void sock_edemux(struct sk_buff *skb) 431 { 432 sock_gen_put(skb->sk); 433 } 434 EXPORT_SYMBOL(sock_edemux); 435 436 struct sock *__inet_lookup_established(struct net *net, 437 struct inet_hashinfo *hashinfo, 438 const __be32 saddr, const __be16 sport, 439 const __be32 daddr, const u16 hnum, 440 const int dif, const int sdif) 441 { 442 INET_ADDR_COOKIE(acookie, saddr, daddr); 443 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 444 struct sock *sk; 445 const struct hlist_nulls_node *node; 446 /* Optimize here for direct hit, only listening connections can 447 * have wildcards anyways. 448 */ 449 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport); 450 unsigned int slot = hash & hashinfo->ehash_mask; 451 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 452 453 begin: 454 sk_nulls_for_each_rcu(sk, node, &head->chain) { 455 if (sk->sk_hash != hash) 456 continue; 457 if (likely(inet_match(net, sk, acookie, ports, dif, sdif))) { 458 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) 459 goto out; 460 if (unlikely(!inet_match(net, sk, acookie, 461 ports, dif, sdif))) { 462 sock_gen_put(sk); 463 goto begin; 464 } 465 goto found; 466 } 467 } 468 /* 469 * if the nulls value we got at the end of this lookup is 470 * not the expected one, we must restart lookup. 471 * We probably met an item that was moved to another chain. 472 */ 473 if (get_nulls_value(node) != slot) 474 goto begin; 475 out: 476 sk = NULL; 477 found: 478 return sk; 479 } 480 EXPORT_SYMBOL_GPL(__inet_lookup_established); 481 482 /* called with local bh disabled */ 483 static int __inet_check_established(struct inet_timewait_death_row *death_row, 484 struct sock *sk, __u16 lport, 485 struct inet_timewait_sock **twp) 486 { 487 struct inet_hashinfo *hinfo = death_row->hashinfo; 488 struct inet_sock *inet = inet_sk(sk); 489 __be32 daddr = inet->inet_rcv_saddr; 490 __be32 saddr = inet->inet_daddr; 491 int dif = sk->sk_bound_dev_if; 492 struct net *net = sock_net(sk); 493 int sdif = l3mdev_master_ifindex_by_index(net, dif); 494 INET_ADDR_COOKIE(acookie, saddr, daddr); 495 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 496 unsigned int hash = inet_ehashfn(net, daddr, lport, 497 saddr, inet->inet_dport); 498 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 499 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 500 struct sock *sk2; 501 const struct hlist_nulls_node *node; 502 struct inet_timewait_sock *tw = NULL; 503 504 spin_lock(lock); 505 506 sk_nulls_for_each(sk2, node, &head->chain) { 507 if (sk2->sk_hash != hash) 508 continue; 509 510 if (likely(inet_match(net, sk2, acookie, ports, dif, sdif))) { 511 if (sk2->sk_state == TCP_TIME_WAIT) { 512 tw = inet_twsk(sk2); 513 if (twsk_unique(sk, sk2, twp)) 514 break; 515 } 516 goto not_unique; 517 } 518 } 519 520 /* Must record num and sport now. Otherwise we will see 521 * in hash table socket with a funny identity. 522 */ 523 inet->inet_num = lport; 524 inet->inet_sport = htons(lport); 525 sk->sk_hash = hash; 526 WARN_ON(!sk_unhashed(sk)); 527 __sk_nulls_add_node_rcu(sk, &head->chain); 528 if (tw) { 529 sk_nulls_del_node_init_rcu((struct sock *)tw); 530 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 531 } 532 spin_unlock(lock); 533 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 534 535 if (twp) { 536 *twp = tw; 537 } else if (tw) { 538 /* Silly. Should hash-dance instead... */ 539 inet_twsk_deschedule_put(tw); 540 } 541 return 0; 542 543 not_unique: 544 spin_unlock(lock); 545 return -EADDRNOTAVAIL; 546 } 547 548 static u64 inet_sk_port_offset(const struct sock *sk) 549 { 550 const struct inet_sock *inet = inet_sk(sk); 551 552 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr, 553 inet->inet_daddr, 554 inet->inet_dport); 555 } 556 557 /* Searches for an exsiting socket in the ehash bucket list. 558 * Returns true if found, false otherwise. 559 */ 560 static bool inet_ehash_lookup_by_sk(struct sock *sk, 561 struct hlist_nulls_head *list) 562 { 563 const __portpair ports = INET_COMBINED_PORTS(sk->sk_dport, sk->sk_num); 564 const int sdif = sk->sk_bound_dev_if; 565 const int dif = sk->sk_bound_dev_if; 566 const struct hlist_nulls_node *node; 567 struct net *net = sock_net(sk); 568 struct sock *esk; 569 570 INET_ADDR_COOKIE(acookie, sk->sk_daddr, sk->sk_rcv_saddr); 571 572 sk_nulls_for_each_rcu(esk, node, list) { 573 if (esk->sk_hash != sk->sk_hash) 574 continue; 575 if (sk->sk_family == AF_INET) { 576 if (unlikely(inet_match(net, esk, acookie, 577 ports, dif, sdif))) { 578 return true; 579 } 580 } 581 #if IS_ENABLED(CONFIG_IPV6) 582 else if (sk->sk_family == AF_INET6) { 583 if (unlikely(inet6_match(net, esk, 584 &sk->sk_v6_daddr, 585 &sk->sk_v6_rcv_saddr, 586 ports, dif, sdif))) { 587 return true; 588 } 589 } 590 #endif 591 } 592 return false; 593 } 594 595 /* Insert a socket into ehash, and eventually remove another one 596 * (The another one can be a SYN_RECV or TIMEWAIT) 597 * If an existing socket already exists, socket sk is not inserted, 598 * and sets found_dup_sk parameter to true. 599 */ 600 bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk) 601 { 602 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 603 struct hlist_nulls_head *list; 604 struct inet_ehash_bucket *head; 605 spinlock_t *lock; 606 bool ret = true; 607 608 WARN_ON_ONCE(!sk_unhashed(sk)); 609 610 sk->sk_hash = sk_ehashfn(sk); 611 head = inet_ehash_bucket(hashinfo, sk->sk_hash); 612 list = &head->chain; 613 lock = inet_ehash_lockp(hashinfo, sk->sk_hash); 614 615 spin_lock(lock); 616 if (osk) { 617 WARN_ON_ONCE(sk->sk_hash != osk->sk_hash); 618 ret = sk_nulls_del_node_init_rcu(osk); 619 } else if (found_dup_sk) { 620 *found_dup_sk = inet_ehash_lookup_by_sk(sk, list); 621 if (*found_dup_sk) 622 ret = false; 623 } 624 625 if (ret) 626 __sk_nulls_add_node_rcu(sk, list); 627 628 spin_unlock(lock); 629 630 return ret; 631 } 632 633 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, bool *found_dup_sk) 634 { 635 bool ok = inet_ehash_insert(sk, osk, found_dup_sk); 636 637 if (ok) { 638 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 639 } else { 640 this_cpu_inc(*sk->sk_prot->orphan_count); 641 inet_sk_set_state(sk, TCP_CLOSE); 642 sock_set_flag(sk, SOCK_DEAD); 643 inet_csk_destroy_sock(sk); 644 } 645 return ok; 646 } 647 EXPORT_SYMBOL_GPL(inet_ehash_nolisten); 648 649 static int inet_reuseport_add_sock(struct sock *sk, 650 struct inet_listen_hashbucket *ilb) 651 { 652 struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash; 653 const struct hlist_nulls_node *node; 654 struct sock *sk2; 655 kuid_t uid = sock_i_uid(sk); 656 657 sk_nulls_for_each_rcu(sk2, node, &ilb->nulls_head) { 658 if (sk2 != sk && 659 sk2->sk_family == sk->sk_family && 660 ipv6_only_sock(sk2) == ipv6_only_sock(sk) && 661 sk2->sk_bound_dev_if == sk->sk_bound_dev_if && 662 inet_csk(sk2)->icsk_bind_hash == tb && 663 sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) && 664 inet_rcv_saddr_equal(sk, sk2, false)) 665 return reuseport_add_sock(sk, sk2, 666 inet_rcv_saddr_any(sk)); 667 } 668 669 return reuseport_alloc(sk, inet_rcv_saddr_any(sk)); 670 } 671 672 int __inet_hash(struct sock *sk, struct sock *osk) 673 { 674 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 675 struct inet_listen_hashbucket *ilb2; 676 int err = 0; 677 678 if (sk->sk_state != TCP_LISTEN) { 679 local_bh_disable(); 680 inet_ehash_nolisten(sk, osk, NULL); 681 local_bh_enable(); 682 return 0; 683 } 684 WARN_ON(!sk_unhashed(sk)); 685 ilb2 = inet_lhash2_bucket_sk(hashinfo, sk); 686 687 spin_lock(&ilb2->lock); 688 if (sk->sk_reuseport) { 689 err = inet_reuseport_add_sock(sk, ilb2); 690 if (err) 691 goto unlock; 692 } 693 if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport && 694 sk->sk_family == AF_INET6) 695 __sk_nulls_add_node_tail_rcu(sk, &ilb2->nulls_head); 696 else 697 __sk_nulls_add_node_rcu(sk, &ilb2->nulls_head); 698 sock_set_flag(sk, SOCK_RCU_FREE); 699 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 700 unlock: 701 spin_unlock(&ilb2->lock); 702 703 return err; 704 } 705 EXPORT_SYMBOL(__inet_hash); 706 707 int inet_hash(struct sock *sk) 708 { 709 int err = 0; 710 711 if (sk->sk_state != TCP_CLOSE) 712 err = __inet_hash(sk, NULL); 713 714 return err; 715 } 716 EXPORT_SYMBOL_GPL(inet_hash); 717 718 void inet_unhash(struct sock *sk) 719 { 720 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 721 722 if (sk_unhashed(sk)) 723 return; 724 725 if (sk->sk_state == TCP_LISTEN) { 726 struct inet_listen_hashbucket *ilb2; 727 728 ilb2 = inet_lhash2_bucket_sk(hashinfo, sk); 729 /* Don't disable bottom halves while acquiring the lock to 730 * avoid circular locking dependency on PREEMPT_RT. 731 */ 732 spin_lock(&ilb2->lock); 733 if (sk_unhashed(sk)) { 734 spin_unlock(&ilb2->lock); 735 return; 736 } 737 738 if (rcu_access_pointer(sk->sk_reuseport_cb)) 739 reuseport_stop_listen_sock(sk); 740 741 __sk_nulls_del_node_init_rcu(sk); 742 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 743 spin_unlock(&ilb2->lock); 744 } else { 745 spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash); 746 747 spin_lock_bh(lock); 748 if (sk_unhashed(sk)) { 749 spin_unlock_bh(lock); 750 return; 751 } 752 __sk_nulls_del_node_init_rcu(sk); 753 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 754 spin_unlock_bh(lock); 755 } 756 } 757 EXPORT_SYMBOL_GPL(inet_unhash); 758 759 static bool check_bind2_bucket_match(struct inet_bind2_bucket *tb, 760 struct net *net, unsigned short port, 761 int l3mdev, struct sock *sk) 762 { 763 #if IS_ENABLED(CONFIG_IPV6) 764 if (sk->sk_family == AF_INET6) 765 return net_eq(ib2_net(tb), net) && tb->port == port && 766 tb->l3mdev == l3mdev && 767 ipv6_addr_equal(&tb->v6_rcv_saddr, &sk->sk_v6_rcv_saddr); 768 else 769 #endif 770 return net_eq(ib2_net(tb), net) && tb->port == port && 771 tb->l3mdev == l3mdev && tb->rcv_saddr == sk->sk_rcv_saddr; 772 } 773 774 bool check_bind2_bucket_match_nulladdr(struct inet_bind2_bucket *tb, 775 struct net *net, const unsigned short port, 776 int l3mdev, const struct sock *sk) 777 { 778 #if IS_ENABLED(CONFIG_IPV6) 779 struct in6_addr nulladdr = {}; 780 781 if (sk->sk_family == AF_INET6) 782 return net_eq(ib2_net(tb), net) && tb->port == port && 783 tb->l3mdev == l3mdev && 784 ipv6_addr_equal(&tb->v6_rcv_saddr, &nulladdr); 785 else 786 #endif 787 return net_eq(ib2_net(tb), net) && tb->port == port && 788 tb->l3mdev == l3mdev && tb->rcv_saddr == 0; 789 } 790 791 static struct inet_bind2_hashbucket * 792 inet_bhashfn_portaddr(struct inet_hashinfo *hinfo, const struct sock *sk, 793 const struct net *net, unsigned short port) 794 { 795 u32 hash; 796 797 #if IS_ENABLED(CONFIG_IPV6) 798 if (sk->sk_family == AF_INET6) 799 hash = ipv6_portaddr_hash(net, &sk->sk_v6_rcv_saddr, port); 800 else 801 #endif 802 hash = ipv4_portaddr_hash(net, sk->sk_rcv_saddr, port); 803 return &hinfo->bhash2[hash & (hinfo->bhash_size - 1)]; 804 } 805 806 /* This should only be called when the spinlock for the socket's corresponding 807 * bind_hashbucket is held 808 */ 809 struct inet_bind2_bucket * 810 inet_bind2_bucket_find(struct inet_hashinfo *hinfo, struct net *net, 811 const unsigned short port, int l3mdev, struct sock *sk, 812 struct inet_bind2_hashbucket **head) 813 { 814 struct inet_bind2_bucket *bhash2 = NULL; 815 struct inet_bind2_hashbucket *h; 816 817 h = inet_bhashfn_portaddr(hinfo, sk, net, port); 818 inet_bind_bucket_for_each(bhash2, &h->chain) { 819 if (check_bind2_bucket_match(bhash2, net, port, l3mdev, sk)) 820 break; 821 } 822 823 if (head) 824 *head = h; 825 826 return bhash2; 827 } 828 829 /* RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm 830 * Note that we use 32bit integers (vs RFC 'short integers') 831 * because 2^16 is not a multiple of num_ephemeral and this 832 * property might be used by clever attacker. 833 * RFC claims using TABLE_LENGTH=10 buckets gives an improvement, though 834 * attacks were since demonstrated, thus we use 65536 instead to really 835 * give more isolation and privacy, at the expense of 256kB of kernel 836 * memory. 837 */ 838 #define INET_TABLE_PERTURB_SHIFT 16 839 #define INET_TABLE_PERTURB_SIZE (1 << INET_TABLE_PERTURB_SHIFT) 840 static u32 *table_perturb; 841 842 int __inet_hash_connect(struct inet_timewait_death_row *death_row, 843 struct sock *sk, u64 port_offset, 844 int (*check_established)(struct inet_timewait_death_row *, 845 struct sock *, __u16, struct inet_timewait_sock **)) 846 { 847 struct inet_hashinfo *hinfo = death_row->hashinfo; 848 struct inet_timewait_sock *tw = NULL; 849 struct inet_bind2_hashbucket *head2; 850 struct inet_bind_hashbucket *head; 851 int port = inet_sk(sk)->inet_num; 852 struct net *net = sock_net(sk); 853 struct inet_bind2_bucket *tb2; 854 struct inet_bind_bucket *tb; 855 bool tb_created = false; 856 u32 remaining, offset; 857 int ret, i, low, high; 858 int l3mdev; 859 u32 index; 860 861 if (port) { 862 head = &hinfo->bhash[inet_bhashfn(net, port, 863 hinfo->bhash_size)]; 864 tb = inet_csk(sk)->icsk_bind_hash; 865 spin_lock_bh(&head->lock); 866 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { 867 inet_ehash_nolisten(sk, NULL, NULL); 868 spin_unlock_bh(&head->lock); 869 return 0; 870 } 871 spin_unlock(&head->lock); 872 /* No definite answer... Walk to established hash table */ 873 ret = check_established(death_row, sk, port, NULL); 874 local_bh_enable(); 875 return ret; 876 } 877 878 l3mdev = inet_sk_bound_l3mdev(sk); 879 880 inet_get_local_port_range(net, &low, &high); 881 high++; /* [32768, 60999] -> [32768, 61000[ */ 882 remaining = high - low; 883 if (likely(remaining > 1)) 884 remaining &= ~1U; 885 886 net_get_random_once(table_perturb, 887 INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb)); 888 index = port_offset & (INET_TABLE_PERTURB_SIZE - 1); 889 890 offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32); 891 offset %= remaining; 892 893 /* In first pass we try ports of @low parity. 894 * inet_csk_get_port() does the opposite choice. 895 */ 896 offset &= ~1U; 897 other_parity_scan: 898 port = low + offset; 899 for (i = 0; i < remaining; i += 2, port += 2) { 900 if (unlikely(port >= high)) 901 port -= remaining; 902 if (inet_is_local_reserved_port(net, port)) 903 continue; 904 head = &hinfo->bhash[inet_bhashfn(net, port, 905 hinfo->bhash_size)]; 906 spin_lock_bh(&head->lock); 907 908 /* Does not bother with rcv_saddr checks, because 909 * the established check is already unique enough. 910 */ 911 inet_bind_bucket_for_each(tb, &head->chain) { 912 if (check_bind_bucket_match(tb, net, port, l3mdev)) { 913 if (tb->fastreuse >= 0 || 914 tb->fastreuseport >= 0) 915 goto next_port; 916 WARN_ON(hlist_empty(&tb->owners)); 917 if (!check_established(death_row, sk, 918 port, &tw)) 919 goto ok; 920 goto next_port; 921 } 922 } 923 924 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, 925 net, head, port, l3mdev); 926 if (!tb) { 927 spin_unlock_bh(&head->lock); 928 return -ENOMEM; 929 } 930 tb_created = true; 931 tb->fastreuse = -1; 932 tb->fastreuseport = -1; 933 goto ok; 934 next_port: 935 spin_unlock_bh(&head->lock); 936 cond_resched(); 937 } 938 939 offset++; 940 if ((offset & 1) && remaining > 1) 941 goto other_parity_scan; 942 943 return -EADDRNOTAVAIL; 944 945 ok: 946 /* Find the corresponding tb2 bucket since we need to 947 * add the socket to the bhash2 table as well 948 */ 949 tb2 = inet_bind2_bucket_find(hinfo, net, port, l3mdev, sk, &head2); 950 if (!tb2) { 951 tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep, net, 952 head2, port, l3mdev, sk); 953 if (!tb2) 954 goto error; 955 } 956 957 /* Here we want to add a little bit of randomness to the next source 958 * port that will be chosen. We use a max() with a random here so that 959 * on low contention the randomness is maximal and on high contention 960 * it may be inexistent. 961 */ 962 i = max_t(int, i, (prandom_u32() & 7) * 2); 963 WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2); 964 965 /* Head lock still held and bh's disabled */ 966 inet_bind_hash(sk, tb, tb2, port); 967 if (sk_unhashed(sk)) { 968 inet_sk(sk)->inet_sport = htons(port); 969 inet_ehash_nolisten(sk, (struct sock *)tw, NULL); 970 } 971 if (tw) 972 inet_twsk_bind_unhash(tw, hinfo); 973 spin_unlock(&head->lock); 974 if (tw) 975 inet_twsk_deschedule_put(tw); 976 local_bh_enable(); 977 return 0; 978 979 error: 980 if (tb_created) 981 inet_bind_bucket_destroy(hinfo->bind_bucket_cachep, tb); 982 spin_unlock_bh(&head->lock); 983 return -ENOMEM; 984 } 985 986 /* 987 * Bind a port for a connect operation and hash it. 988 */ 989 int inet_hash_connect(struct inet_timewait_death_row *death_row, 990 struct sock *sk) 991 { 992 u64 port_offset = 0; 993 994 if (!inet_sk(sk)->inet_num) 995 port_offset = inet_sk_port_offset(sk); 996 return __inet_hash_connect(death_row, sk, port_offset, 997 __inet_check_established); 998 } 999 EXPORT_SYMBOL_GPL(inet_hash_connect); 1000 1001 static void init_hashinfo_lhash2(struct inet_hashinfo *h) 1002 { 1003 int i; 1004 1005 for (i = 0; i <= h->lhash2_mask; i++) { 1006 spin_lock_init(&h->lhash2[i].lock); 1007 INIT_HLIST_NULLS_HEAD(&h->lhash2[i].nulls_head, 1008 i + LISTENING_NULLS_BASE); 1009 } 1010 } 1011 1012 void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name, 1013 unsigned long numentries, int scale, 1014 unsigned long low_limit, 1015 unsigned long high_limit) 1016 { 1017 h->lhash2 = alloc_large_system_hash(name, 1018 sizeof(*h->lhash2), 1019 numentries, 1020 scale, 1021 0, 1022 NULL, 1023 &h->lhash2_mask, 1024 low_limit, 1025 high_limit); 1026 init_hashinfo_lhash2(h); 1027 1028 /* this one is used for source ports of outgoing connections */ 1029 table_perturb = alloc_large_system_hash("Table-perturb", 1030 sizeof(*table_perturb), 1031 INET_TABLE_PERTURB_SIZE, 1032 0, 0, NULL, NULL, 1033 INET_TABLE_PERTURB_SIZE, 1034 INET_TABLE_PERTURB_SIZE); 1035 } 1036 1037 int inet_hashinfo2_init_mod(struct inet_hashinfo *h) 1038 { 1039 h->lhash2 = kmalloc_array(INET_LHTABLE_SIZE, sizeof(*h->lhash2), GFP_KERNEL); 1040 if (!h->lhash2) 1041 return -ENOMEM; 1042 1043 h->lhash2_mask = INET_LHTABLE_SIZE - 1; 1044 /* INET_LHTABLE_SIZE must be a power of 2 */ 1045 BUG_ON(INET_LHTABLE_SIZE & h->lhash2_mask); 1046 1047 init_hashinfo_lhash2(h); 1048 return 0; 1049 } 1050 EXPORT_SYMBOL_GPL(inet_hashinfo2_init_mod); 1051 1052 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) 1053 { 1054 unsigned int locksz = sizeof(spinlock_t); 1055 unsigned int i, nblocks = 1; 1056 1057 if (locksz != 0) { 1058 /* allocate 2 cache lines or at least one spinlock per cpu */ 1059 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U); 1060 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus()); 1061 1062 /* no more locks than number of hash buckets */ 1063 nblocks = min(nblocks, hashinfo->ehash_mask + 1); 1064 1065 hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL); 1066 if (!hashinfo->ehash_locks) 1067 return -ENOMEM; 1068 1069 for (i = 0; i < nblocks; i++) 1070 spin_lock_init(&hashinfo->ehash_locks[i]); 1071 } 1072 hashinfo->ehash_locks_mask = nblocks - 1; 1073 return 0; 1074 } 1075 EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc); 1076