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 * Support for INET connection oriented protocols. 8 * 9 * Authors: See the TCP sources 10 */ 11 12 #include <linux/module.h> 13 #include <linux/jhash.h> 14 15 #include <net/inet_connection_sock.h> 16 #include <net/inet_hashtables.h> 17 #include <net/inet_timewait_sock.h> 18 #include <net/ip.h> 19 #include <net/route.h> 20 #include <net/tcp_states.h> 21 #include <net/xfrm.h> 22 #include <net/tcp.h> 23 #include <net/sock_reuseport.h> 24 #include <net/addrconf.h> 25 26 #if IS_ENABLED(CONFIG_IPV6) 27 /* match_sk*_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses 28 * if IPv6 only, and any IPv4 addresses 29 * if not IPv6 only 30 * match_sk*_wildcard == false: addresses must be exactly the same, i.e. 31 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY, 32 * and 0.0.0.0 equals to 0.0.0.0 only 33 */ 34 static bool ipv6_rcv_saddr_equal(const struct in6_addr *sk1_rcv_saddr6, 35 const struct in6_addr *sk2_rcv_saddr6, 36 __be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, 37 bool sk1_ipv6only, bool sk2_ipv6only, 38 bool match_sk1_wildcard, 39 bool match_sk2_wildcard) 40 { 41 int addr_type = ipv6_addr_type(sk1_rcv_saddr6); 42 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED; 43 44 /* if both are mapped, treat as IPv4 */ 45 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) { 46 if (!sk2_ipv6only) { 47 if (sk1_rcv_saddr == sk2_rcv_saddr) 48 return true; 49 return (match_sk1_wildcard && !sk1_rcv_saddr) || 50 (match_sk2_wildcard && !sk2_rcv_saddr); 51 } 52 return false; 53 } 54 55 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY) 56 return true; 57 58 if (addr_type2 == IPV6_ADDR_ANY && match_sk2_wildcard && 59 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED)) 60 return true; 61 62 if (addr_type == IPV6_ADDR_ANY && match_sk1_wildcard && 63 !(sk1_ipv6only && addr_type2 == IPV6_ADDR_MAPPED)) 64 return true; 65 66 if (sk2_rcv_saddr6 && 67 ipv6_addr_equal(sk1_rcv_saddr6, sk2_rcv_saddr6)) 68 return true; 69 70 return false; 71 } 72 #endif 73 74 /* match_sk*_wildcard == true: 0.0.0.0 equals to any IPv4 addresses 75 * match_sk*_wildcard == false: addresses must be exactly the same, i.e. 76 * 0.0.0.0 only equals to 0.0.0.0 77 */ 78 static bool ipv4_rcv_saddr_equal(__be32 sk1_rcv_saddr, __be32 sk2_rcv_saddr, 79 bool sk2_ipv6only, bool match_sk1_wildcard, 80 bool match_sk2_wildcard) 81 { 82 if (!sk2_ipv6only) { 83 if (sk1_rcv_saddr == sk2_rcv_saddr) 84 return true; 85 return (match_sk1_wildcard && !sk1_rcv_saddr) || 86 (match_sk2_wildcard && !sk2_rcv_saddr); 87 } 88 return false; 89 } 90 91 bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2, 92 bool match_wildcard) 93 { 94 #if IS_ENABLED(CONFIG_IPV6) 95 if (sk->sk_family == AF_INET6) 96 return ipv6_rcv_saddr_equal(&sk->sk_v6_rcv_saddr, 97 inet6_rcv_saddr(sk2), 98 sk->sk_rcv_saddr, 99 sk2->sk_rcv_saddr, 100 ipv6_only_sock(sk), 101 ipv6_only_sock(sk2), 102 match_wildcard, 103 match_wildcard); 104 #endif 105 return ipv4_rcv_saddr_equal(sk->sk_rcv_saddr, sk2->sk_rcv_saddr, 106 ipv6_only_sock(sk2), match_wildcard, 107 match_wildcard); 108 } 109 EXPORT_SYMBOL(inet_rcv_saddr_equal); 110 111 bool inet_rcv_saddr_any(const struct sock *sk) 112 { 113 #if IS_ENABLED(CONFIG_IPV6) 114 if (sk->sk_family == AF_INET6) 115 return ipv6_addr_any(&sk->sk_v6_rcv_saddr); 116 #endif 117 return !sk->sk_rcv_saddr; 118 } 119 120 static bool use_bhash2_on_bind(const struct sock *sk) 121 { 122 #if IS_ENABLED(CONFIG_IPV6) 123 int addr_type; 124 125 if (sk->sk_family == AF_INET6) { 126 addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr); 127 return addr_type != IPV6_ADDR_ANY && 128 addr_type != IPV6_ADDR_MAPPED; 129 } 130 #endif 131 return sk->sk_rcv_saddr != htonl(INADDR_ANY); 132 } 133 134 static u32 get_bhash2_nulladdr_hash(const struct sock *sk, struct net *net, 135 int port) 136 { 137 #if IS_ENABLED(CONFIG_IPV6) 138 struct in6_addr nulladdr = {}; 139 140 if (sk->sk_family == AF_INET6) 141 return ipv6_portaddr_hash(net, &nulladdr, port); 142 #endif 143 return ipv4_portaddr_hash(net, 0, port); 144 } 145 146 void inet_get_local_port_range(struct net *net, int *low, int *high) 147 { 148 unsigned int seq; 149 150 do { 151 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock); 152 153 *low = net->ipv4.ip_local_ports.range[0]; 154 *high = net->ipv4.ip_local_ports.range[1]; 155 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq)); 156 } 157 EXPORT_SYMBOL(inet_get_local_port_range); 158 159 static bool bind_conflict_exist(const struct sock *sk, struct sock *sk2, 160 kuid_t sk_uid, bool relax, 161 bool reuseport_cb_ok, bool reuseport_ok) 162 { 163 int bound_dev_if2; 164 165 if (sk == sk2) 166 return false; 167 168 bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if); 169 170 if (!sk->sk_bound_dev_if || !bound_dev_if2 || 171 sk->sk_bound_dev_if == bound_dev_if2) { 172 if (sk->sk_reuse && sk2->sk_reuse && 173 sk2->sk_state != TCP_LISTEN) { 174 if (!relax || (!reuseport_ok && sk->sk_reuseport && 175 sk2->sk_reuseport && reuseport_cb_ok && 176 (sk2->sk_state == TCP_TIME_WAIT || 177 uid_eq(sk_uid, sock_i_uid(sk2))))) 178 return true; 179 } else if (!reuseport_ok || !sk->sk_reuseport || 180 !sk2->sk_reuseport || !reuseport_cb_ok || 181 (sk2->sk_state != TCP_TIME_WAIT && 182 !uid_eq(sk_uid, sock_i_uid(sk2)))) { 183 return true; 184 } 185 } 186 return false; 187 } 188 189 static bool check_bhash2_conflict(const struct sock *sk, 190 struct inet_bind2_bucket *tb2, kuid_t sk_uid, 191 bool relax, bool reuseport_cb_ok, 192 bool reuseport_ok) 193 { 194 struct sock *sk2; 195 196 sk_for_each_bound_bhash2(sk2, &tb2->owners) { 197 if (sk->sk_family == AF_INET && ipv6_only_sock(sk2)) 198 continue; 199 200 if (bind_conflict_exist(sk, sk2, sk_uid, relax, 201 reuseport_cb_ok, reuseport_ok)) 202 return true; 203 } 204 return false; 205 } 206 207 /* This should be called only when the corresponding inet_bind_bucket spinlock 208 * is held 209 */ 210 static int inet_csk_bind_conflict(const struct sock *sk, int port, 211 struct inet_bind_bucket *tb, 212 struct inet_bind2_bucket *tb2, /* may be null */ 213 bool relax, bool reuseport_ok) 214 { 215 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo; 216 kuid_t uid = sock_i_uid((struct sock *)sk); 217 struct sock_reuseport *reuseport_cb; 218 struct inet_bind2_hashbucket *head2; 219 bool reuseport_cb_ok; 220 struct sock *sk2; 221 struct net *net; 222 int l3mdev; 223 u32 hash; 224 225 rcu_read_lock(); 226 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb); 227 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */ 228 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks); 229 rcu_read_unlock(); 230 231 /* 232 * Unlike other sk lookup places we do not check 233 * for sk_net here, since _all_ the socks listed 234 * in tb->owners and tb2->owners list belong 235 * to the same net 236 */ 237 238 if (!use_bhash2_on_bind(sk)) { 239 sk_for_each_bound(sk2, &tb->owners) 240 if (bind_conflict_exist(sk, sk2, uid, relax, 241 reuseport_cb_ok, reuseport_ok) && 242 inet_rcv_saddr_equal(sk, sk2, true)) 243 return true; 244 245 return false; 246 } 247 248 if (tb2 && check_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok, 249 reuseport_ok)) 250 return true; 251 252 net = sock_net(sk); 253 254 /* check there's no conflict with an existing IPV6_ADDR_ANY (if ipv6) or 255 * INADDR_ANY (if ipv4) socket. 256 */ 257 hash = get_bhash2_nulladdr_hash(sk, net, port); 258 head2 = &hinfo->bhash2[hash & (hinfo->bhash_size - 1)]; 259 260 l3mdev = inet_sk_bound_l3mdev(sk); 261 inet_bind_bucket_for_each(tb2, &head2->chain) 262 if (check_bind2_bucket_match_nulladdr(tb2, net, port, l3mdev, sk)) 263 break; 264 265 if (tb2 && check_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok, 266 reuseport_ok)) 267 return true; 268 269 return false; 270 } 271 272 /* 273 * Find an open port number for the socket. Returns with the 274 * inet_bind_hashbucket lock held. 275 */ 276 static struct inet_bind_hashbucket * 277 inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, 278 struct inet_bind2_bucket **tb2_ret, 279 struct inet_bind2_hashbucket **head2_ret, int *port_ret) 280 { 281 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo; 282 struct inet_bind2_hashbucket *head2; 283 struct inet_bind_hashbucket *head; 284 struct net *net = sock_net(sk); 285 int i, low, high, attempt_half; 286 struct inet_bind2_bucket *tb2; 287 struct inet_bind_bucket *tb; 288 u32 remaining, offset; 289 bool relax = false; 290 int port = 0; 291 int l3mdev; 292 293 l3mdev = inet_sk_bound_l3mdev(sk); 294 ports_exhausted: 295 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0; 296 other_half_scan: 297 inet_get_local_port_range(net, &low, &high); 298 high++; /* [32768, 60999] -> [32768, 61000[ */ 299 if (high - low < 4) 300 attempt_half = 0; 301 if (attempt_half) { 302 int half = low + (((high - low) >> 2) << 1); 303 304 if (attempt_half == 1) 305 high = half; 306 else 307 low = half; 308 } 309 remaining = high - low; 310 if (likely(remaining > 1)) 311 remaining &= ~1U; 312 313 offset = prandom_u32() % remaining; 314 /* __inet_hash_connect() favors ports having @low parity 315 * We do the opposite to not pollute connect() users. 316 */ 317 offset |= 1U; 318 319 other_parity_scan: 320 port = low + offset; 321 for (i = 0; i < remaining; i += 2, port += 2) { 322 if (unlikely(port >= high)) 323 port -= remaining; 324 if (inet_is_local_reserved_port(net, port)) 325 continue; 326 head = &hinfo->bhash[inet_bhashfn(net, port, 327 hinfo->bhash_size)]; 328 spin_lock_bh(&head->lock); 329 tb2 = inet_bind2_bucket_find(hinfo, net, port, l3mdev, sk, 330 &head2); 331 inet_bind_bucket_for_each(tb, &head->chain) 332 if (check_bind_bucket_match(tb, net, port, l3mdev)) { 333 if (!inet_csk_bind_conflict(sk, port, tb, tb2, 334 relax, false)) 335 goto success; 336 goto next_port; 337 } 338 tb = NULL; 339 goto success; 340 next_port: 341 spin_unlock_bh(&head->lock); 342 cond_resched(); 343 } 344 345 offset--; 346 if (!(offset & 1)) 347 goto other_parity_scan; 348 349 if (attempt_half == 1) { 350 /* OK we now try the upper half of the range */ 351 attempt_half = 2; 352 goto other_half_scan; 353 } 354 355 if (net->ipv4.sysctl_ip_autobind_reuse && !relax) { 356 /* We still have a chance to connect to different destinations */ 357 relax = true; 358 goto ports_exhausted; 359 } 360 return NULL; 361 success: 362 *port_ret = port; 363 *tb_ret = tb; 364 *tb2_ret = tb2; 365 *head2_ret = head2; 366 return head; 367 } 368 369 static inline int sk_reuseport_match(struct inet_bind_bucket *tb, 370 struct sock *sk) 371 { 372 kuid_t uid = sock_i_uid(sk); 373 374 if (tb->fastreuseport <= 0) 375 return 0; 376 if (!sk->sk_reuseport) 377 return 0; 378 if (rcu_access_pointer(sk->sk_reuseport_cb)) 379 return 0; 380 if (!uid_eq(tb->fastuid, uid)) 381 return 0; 382 /* We only need to check the rcv_saddr if this tb was once marked 383 * without fastreuseport and then was reset, as we can only know that 384 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the 385 * owners list. 386 */ 387 if (tb->fastreuseport == FASTREUSEPORT_ANY) 388 return 1; 389 #if IS_ENABLED(CONFIG_IPV6) 390 if (tb->fast_sk_family == AF_INET6) 391 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr, 392 inet6_rcv_saddr(sk), 393 tb->fast_rcv_saddr, 394 sk->sk_rcv_saddr, 395 tb->fast_ipv6_only, 396 ipv6_only_sock(sk), true, false); 397 #endif 398 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr, 399 ipv6_only_sock(sk), true, false); 400 } 401 402 void inet_csk_update_fastreuse(struct inet_bind_bucket *tb, 403 struct sock *sk) 404 { 405 kuid_t uid = sock_i_uid(sk); 406 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; 407 408 if (hlist_empty(&tb->owners)) { 409 tb->fastreuse = reuse; 410 if (sk->sk_reuseport) { 411 tb->fastreuseport = FASTREUSEPORT_ANY; 412 tb->fastuid = uid; 413 tb->fast_rcv_saddr = sk->sk_rcv_saddr; 414 tb->fast_ipv6_only = ipv6_only_sock(sk); 415 tb->fast_sk_family = sk->sk_family; 416 #if IS_ENABLED(CONFIG_IPV6) 417 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; 418 #endif 419 } else { 420 tb->fastreuseport = 0; 421 } 422 } else { 423 if (!reuse) 424 tb->fastreuse = 0; 425 if (sk->sk_reuseport) { 426 /* We didn't match or we don't have fastreuseport set on 427 * the tb, but we have sk_reuseport set on this socket 428 * and we know that there are no bind conflicts with 429 * this socket in this tb, so reset our tb's reuseport 430 * settings so that any subsequent sockets that match 431 * our current socket will be put on the fast path. 432 * 433 * If we reset we need to set FASTREUSEPORT_STRICT so we 434 * do extra checking for all subsequent sk_reuseport 435 * socks. 436 */ 437 if (!sk_reuseport_match(tb, sk)) { 438 tb->fastreuseport = FASTREUSEPORT_STRICT; 439 tb->fastuid = uid; 440 tb->fast_rcv_saddr = sk->sk_rcv_saddr; 441 tb->fast_ipv6_only = ipv6_only_sock(sk); 442 tb->fast_sk_family = sk->sk_family; 443 #if IS_ENABLED(CONFIG_IPV6) 444 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; 445 #endif 446 } 447 } else { 448 tb->fastreuseport = 0; 449 } 450 } 451 } 452 453 /* Obtain a reference to a local port for the given sock, 454 * if snum is zero it means select any available local port. 455 * We try to allocate an odd port (and leave even ports for connect()) 456 */ 457 int inet_csk_get_port(struct sock *sk, unsigned short snum) 458 { 459 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; 460 struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo; 461 bool bhash_created = false, bhash2_created = false; 462 struct inet_bind2_bucket *tb2 = NULL; 463 struct inet_bind2_hashbucket *head2; 464 struct inet_bind_bucket *tb = NULL; 465 struct inet_bind_hashbucket *head; 466 struct net *net = sock_net(sk); 467 int ret = 1, port = snum; 468 bool found_port = false; 469 int l3mdev; 470 471 l3mdev = inet_sk_bound_l3mdev(sk); 472 473 if (!port) { 474 head = inet_csk_find_open_port(sk, &tb, &tb2, &head2, &port); 475 if (!head) 476 return ret; 477 if (tb && tb2) 478 goto success; 479 found_port = true; 480 } else { 481 head = &hinfo->bhash[inet_bhashfn(net, port, 482 hinfo->bhash_size)]; 483 spin_lock_bh(&head->lock); 484 inet_bind_bucket_for_each(tb, &head->chain) 485 if (check_bind_bucket_match(tb, net, port, l3mdev)) 486 break; 487 488 tb2 = inet_bind2_bucket_find(hinfo, net, port, l3mdev, sk, 489 &head2); 490 } 491 492 if (!tb) { 493 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net, 494 head, port, l3mdev); 495 if (!tb) 496 goto fail_unlock; 497 bhash_created = true; 498 } 499 500 if (!tb2) { 501 tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep, 502 net, head2, port, l3mdev, sk); 503 if (!tb2) 504 goto fail_unlock; 505 bhash2_created = true; 506 } 507 508 /* If we had to find an open port, we already checked for conflicts */ 509 if (!found_port && !hlist_empty(&tb->owners)) { 510 if (sk->sk_reuse == SK_FORCE_REUSE) 511 goto success; 512 513 if ((tb->fastreuse > 0 && reuse) || 514 sk_reuseport_match(tb, sk)) 515 goto success; 516 if (inet_csk_bind_conflict(sk, port, tb, tb2, true, true)) 517 goto fail_unlock; 518 } 519 success: 520 inet_csk_update_fastreuse(tb, sk); 521 522 if (!inet_csk(sk)->icsk_bind_hash) 523 inet_bind_hash(sk, tb, tb2, port); 524 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); 525 WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2); 526 ret = 0; 527 528 fail_unlock: 529 if (ret) { 530 if (bhash_created) 531 inet_bind_bucket_destroy(hinfo->bind_bucket_cachep, tb); 532 if (bhash2_created) 533 inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep, 534 tb2); 535 } 536 spin_unlock_bh(&head->lock); 537 return ret; 538 } 539 EXPORT_SYMBOL_GPL(inet_csk_get_port); 540 541 /* 542 * Wait for an incoming connection, avoid race conditions. This must be called 543 * with the socket locked. 544 */ 545 static int inet_csk_wait_for_connect(struct sock *sk, long timeo) 546 { 547 struct inet_connection_sock *icsk = inet_csk(sk); 548 DEFINE_WAIT(wait); 549 int err; 550 551 /* 552 * True wake-one mechanism for incoming connections: only 553 * one process gets woken up, not the 'whole herd'. 554 * Since we do not 'race & poll' for established sockets 555 * anymore, the common case will execute the loop only once. 556 * 557 * Subtle issue: "add_wait_queue_exclusive()" will be added 558 * after any current non-exclusive waiters, and we know that 559 * it will always _stay_ after any new non-exclusive waiters 560 * because all non-exclusive waiters are added at the 561 * beginning of the wait-queue. As such, it's ok to "drop" 562 * our exclusiveness temporarily when we get woken up without 563 * having to remove and re-insert us on the wait queue. 564 */ 565 for (;;) { 566 prepare_to_wait_exclusive(sk_sleep(sk), &wait, 567 TASK_INTERRUPTIBLE); 568 release_sock(sk); 569 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) 570 timeo = schedule_timeout(timeo); 571 sched_annotate_sleep(); 572 lock_sock(sk); 573 err = 0; 574 if (!reqsk_queue_empty(&icsk->icsk_accept_queue)) 575 break; 576 err = -EINVAL; 577 if (sk->sk_state != TCP_LISTEN) 578 break; 579 err = sock_intr_errno(timeo); 580 if (signal_pending(current)) 581 break; 582 err = -EAGAIN; 583 if (!timeo) 584 break; 585 } 586 finish_wait(sk_sleep(sk), &wait); 587 return err; 588 } 589 590 /* 591 * This will accept the next outstanding connection. 592 */ 593 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern) 594 { 595 struct inet_connection_sock *icsk = inet_csk(sk); 596 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 597 struct request_sock *req; 598 struct sock *newsk; 599 int error; 600 601 lock_sock(sk); 602 603 /* We need to make sure that this socket is listening, 604 * and that it has something pending. 605 */ 606 error = -EINVAL; 607 if (sk->sk_state != TCP_LISTEN) 608 goto out_err; 609 610 /* Find already established connection */ 611 if (reqsk_queue_empty(queue)) { 612 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK); 613 614 /* If this is a non blocking socket don't sleep */ 615 error = -EAGAIN; 616 if (!timeo) 617 goto out_err; 618 619 error = inet_csk_wait_for_connect(sk, timeo); 620 if (error) 621 goto out_err; 622 } 623 req = reqsk_queue_remove(queue, sk); 624 newsk = req->sk; 625 626 if (sk->sk_protocol == IPPROTO_TCP && 627 tcp_rsk(req)->tfo_listener) { 628 spin_lock_bh(&queue->fastopenq.lock); 629 if (tcp_rsk(req)->tfo_listener) { 630 /* We are still waiting for the final ACK from 3WHS 631 * so can't free req now. Instead, we set req->sk to 632 * NULL to signify that the child socket is taken 633 * so reqsk_fastopen_remove() will free the req 634 * when 3WHS finishes (or is aborted). 635 */ 636 req->sk = NULL; 637 req = NULL; 638 } 639 spin_unlock_bh(&queue->fastopenq.lock); 640 } 641 642 out: 643 release_sock(sk); 644 if (newsk && mem_cgroup_sockets_enabled) { 645 int amt; 646 647 /* atomically get the memory usage, set and charge the 648 * newsk->sk_memcg. 649 */ 650 lock_sock(newsk); 651 652 /* The socket has not been accepted yet, no need to look at 653 * newsk->sk_wmem_queued. 654 */ 655 amt = sk_mem_pages(newsk->sk_forward_alloc + 656 atomic_read(&newsk->sk_rmem_alloc)); 657 mem_cgroup_sk_alloc(newsk); 658 if (newsk->sk_memcg && amt) 659 mem_cgroup_charge_skmem(newsk->sk_memcg, amt, 660 GFP_KERNEL | __GFP_NOFAIL); 661 662 release_sock(newsk); 663 } 664 if (req) 665 reqsk_put(req); 666 return newsk; 667 out_err: 668 newsk = NULL; 669 req = NULL; 670 *err = error; 671 goto out; 672 } 673 EXPORT_SYMBOL(inet_csk_accept); 674 675 /* 676 * Using different timers for retransmit, delayed acks and probes 677 * We may wish use just one timer maintaining a list of expire jiffies 678 * to optimize. 679 */ 680 void inet_csk_init_xmit_timers(struct sock *sk, 681 void (*retransmit_handler)(struct timer_list *t), 682 void (*delack_handler)(struct timer_list *t), 683 void (*keepalive_handler)(struct timer_list *t)) 684 { 685 struct inet_connection_sock *icsk = inet_csk(sk); 686 687 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0); 688 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0); 689 timer_setup(&sk->sk_timer, keepalive_handler, 0); 690 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 691 } 692 EXPORT_SYMBOL(inet_csk_init_xmit_timers); 693 694 void inet_csk_clear_xmit_timers(struct sock *sk) 695 { 696 struct inet_connection_sock *icsk = inet_csk(sk); 697 698 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 699 700 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 701 sk_stop_timer(sk, &icsk->icsk_delack_timer); 702 sk_stop_timer(sk, &sk->sk_timer); 703 } 704 EXPORT_SYMBOL(inet_csk_clear_xmit_timers); 705 706 void inet_csk_delete_keepalive_timer(struct sock *sk) 707 { 708 sk_stop_timer(sk, &sk->sk_timer); 709 } 710 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer); 711 712 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) 713 { 714 sk_reset_timer(sk, &sk->sk_timer, jiffies + len); 715 } 716 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer); 717 718 struct dst_entry *inet_csk_route_req(const struct sock *sk, 719 struct flowi4 *fl4, 720 const struct request_sock *req) 721 { 722 const struct inet_request_sock *ireq = inet_rsk(req); 723 struct net *net = read_pnet(&ireq->ireq_net); 724 struct ip_options_rcu *opt; 725 struct rtable *rt; 726 727 rcu_read_lock(); 728 opt = rcu_dereference(ireq->ireq_opt); 729 730 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark, 731 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 732 sk->sk_protocol, inet_sk_flowi_flags(sk), 733 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, 734 ireq->ir_loc_addr, ireq->ir_rmt_port, 735 htons(ireq->ir_num), sk->sk_uid); 736 security_req_classify_flow(req, flowi4_to_flowi_common(fl4)); 737 rt = ip_route_output_flow(net, fl4, sk); 738 if (IS_ERR(rt)) 739 goto no_route; 740 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 741 goto route_err; 742 rcu_read_unlock(); 743 return &rt->dst; 744 745 route_err: 746 ip_rt_put(rt); 747 no_route: 748 rcu_read_unlock(); 749 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); 750 return NULL; 751 } 752 EXPORT_SYMBOL_GPL(inet_csk_route_req); 753 754 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk, 755 struct sock *newsk, 756 const struct request_sock *req) 757 { 758 const struct inet_request_sock *ireq = inet_rsk(req); 759 struct net *net = read_pnet(&ireq->ireq_net); 760 struct inet_sock *newinet = inet_sk(newsk); 761 struct ip_options_rcu *opt; 762 struct flowi4 *fl4; 763 struct rtable *rt; 764 765 opt = rcu_dereference(ireq->ireq_opt); 766 fl4 = &newinet->cork.fl.u.ip4; 767 768 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark, 769 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 770 sk->sk_protocol, inet_sk_flowi_flags(sk), 771 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, 772 ireq->ir_loc_addr, ireq->ir_rmt_port, 773 htons(ireq->ir_num), sk->sk_uid); 774 security_req_classify_flow(req, flowi4_to_flowi_common(fl4)); 775 rt = ip_route_output_flow(net, fl4, sk); 776 if (IS_ERR(rt)) 777 goto no_route; 778 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 779 goto route_err; 780 return &rt->dst; 781 782 route_err: 783 ip_rt_put(rt); 784 no_route: 785 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); 786 return NULL; 787 } 788 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); 789 790 /* Decide when to expire the request and when to resend SYN-ACK */ 791 static void syn_ack_recalc(struct request_sock *req, 792 const int max_syn_ack_retries, 793 const u8 rskq_defer_accept, 794 int *expire, int *resend) 795 { 796 if (!rskq_defer_accept) { 797 *expire = req->num_timeout >= max_syn_ack_retries; 798 *resend = 1; 799 return; 800 } 801 *expire = req->num_timeout >= max_syn_ack_retries && 802 (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept); 803 /* Do not resend while waiting for data after ACK, 804 * start to resend on end of deferring period to give 805 * last chance for data or ACK to create established socket. 806 */ 807 *resend = !inet_rsk(req)->acked || 808 req->num_timeout >= rskq_defer_accept - 1; 809 } 810 811 int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req) 812 { 813 int err = req->rsk_ops->rtx_syn_ack(parent, req); 814 815 if (!err) 816 req->num_retrans++; 817 return err; 818 } 819 EXPORT_SYMBOL(inet_rtx_syn_ack); 820 821 static struct request_sock *inet_reqsk_clone(struct request_sock *req, 822 struct sock *sk) 823 { 824 struct sock *req_sk, *nreq_sk; 825 struct request_sock *nreq; 826 827 nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN); 828 if (!nreq) { 829 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE); 830 831 /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */ 832 sock_put(sk); 833 return NULL; 834 } 835 836 req_sk = req_to_sk(req); 837 nreq_sk = req_to_sk(nreq); 838 839 memcpy(nreq_sk, req_sk, 840 offsetof(struct sock, sk_dontcopy_begin)); 841 memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end, 842 req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end)); 843 844 sk_node_init(&nreq_sk->sk_node); 845 nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping; 846 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING 847 nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping; 848 #endif 849 nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu; 850 851 nreq->rsk_listener = sk; 852 853 /* We need not acquire fastopenq->lock 854 * because the child socket is locked in inet_csk_listen_stop(). 855 */ 856 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener) 857 rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq); 858 859 return nreq; 860 } 861 862 static void reqsk_queue_migrated(struct request_sock_queue *queue, 863 const struct request_sock *req) 864 { 865 if (req->num_timeout == 0) 866 atomic_inc(&queue->young); 867 atomic_inc(&queue->qlen); 868 } 869 870 static void reqsk_migrate_reset(struct request_sock *req) 871 { 872 req->saved_syn = NULL; 873 #if IS_ENABLED(CONFIG_IPV6) 874 inet_rsk(req)->ipv6_opt = NULL; 875 inet_rsk(req)->pktopts = NULL; 876 #else 877 inet_rsk(req)->ireq_opt = NULL; 878 #endif 879 } 880 881 /* return true if req was found in the ehash table */ 882 static bool reqsk_queue_unlink(struct request_sock *req) 883 { 884 struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo; 885 bool found = false; 886 887 if (sk_hashed(req_to_sk(req))) { 888 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash); 889 890 spin_lock(lock); 891 found = __sk_nulls_del_node_init_rcu(req_to_sk(req)); 892 spin_unlock(lock); 893 } 894 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer)) 895 reqsk_put(req); 896 return found; 897 } 898 899 bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req) 900 { 901 bool unlinked = reqsk_queue_unlink(req); 902 903 if (unlinked) { 904 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req); 905 reqsk_put(req); 906 } 907 return unlinked; 908 } 909 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop); 910 911 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req) 912 { 913 inet_csk_reqsk_queue_drop(sk, req); 914 reqsk_put(req); 915 } 916 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put); 917 918 static void reqsk_timer_handler(struct timer_list *t) 919 { 920 struct request_sock *req = from_timer(req, t, rsk_timer); 921 struct request_sock *nreq = NULL, *oreq = req; 922 struct sock *sk_listener = req->rsk_listener; 923 struct inet_connection_sock *icsk; 924 struct request_sock_queue *queue; 925 struct net *net; 926 int max_syn_ack_retries, qlen, expire = 0, resend = 0; 927 928 if (inet_sk_state_load(sk_listener) != TCP_LISTEN) { 929 struct sock *nsk; 930 931 nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL); 932 if (!nsk) 933 goto drop; 934 935 nreq = inet_reqsk_clone(req, nsk); 936 if (!nreq) 937 goto drop; 938 939 /* The new timer for the cloned req can decrease the 2 940 * by calling inet_csk_reqsk_queue_drop_and_put(), so 941 * hold another count to prevent use-after-free and 942 * call reqsk_put() just before return. 943 */ 944 refcount_set(&nreq->rsk_refcnt, 2 + 1); 945 timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED); 946 reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req); 947 948 req = nreq; 949 sk_listener = nsk; 950 } 951 952 icsk = inet_csk(sk_listener); 953 net = sock_net(sk_listener); 954 max_syn_ack_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries; 955 /* Normally all the openreqs are young and become mature 956 * (i.e. converted to established socket) for first timeout. 957 * If synack was not acknowledged for 1 second, it means 958 * one of the following things: synack was lost, ack was lost, 959 * rtt is high or nobody planned to ack (i.e. synflood). 960 * When server is a bit loaded, queue is populated with old 961 * open requests, reducing effective size of queue. 962 * When server is well loaded, queue size reduces to zero 963 * after several minutes of work. It is not synflood, 964 * it is normal operation. The solution is pruning 965 * too old entries overriding normal timeout, when 966 * situation becomes dangerous. 967 * 968 * Essentially, we reserve half of room for young 969 * embrions; and abort old ones without pity, if old 970 * ones are about to clog our table. 971 */ 972 queue = &icsk->icsk_accept_queue; 973 qlen = reqsk_queue_len(queue); 974 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) { 975 int young = reqsk_queue_len_young(queue) << 1; 976 977 while (max_syn_ack_retries > 2) { 978 if (qlen < young) 979 break; 980 max_syn_ack_retries--; 981 young <<= 1; 982 } 983 } 984 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept), 985 &expire, &resend); 986 req->rsk_ops->syn_ack_timeout(req); 987 if (!expire && 988 (!resend || 989 !inet_rtx_syn_ack(sk_listener, req) || 990 inet_rsk(req)->acked)) { 991 if (req->num_timeout++ == 0) 992 atomic_dec(&queue->young); 993 mod_timer(&req->rsk_timer, jiffies + reqsk_timeout(req, TCP_RTO_MAX)); 994 995 if (!nreq) 996 return; 997 998 if (!inet_ehash_insert(req_to_sk(nreq), req_to_sk(oreq), NULL)) { 999 /* delete timer */ 1000 inet_csk_reqsk_queue_drop(sk_listener, nreq); 1001 goto no_ownership; 1002 } 1003 1004 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS); 1005 reqsk_migrate_reset(oreq); 1006 reqsk_queue_removed(&inet_csk(oreq->rsk_listener)->icsk_accept_queue, oreq); 1007 reqsk_put(oreq); 1008 1009 reqsk_put(nreq); 1010 return; 1011 } 1012 1013 /* Even if we can clone the req, we may need not retransmit any more 1014 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another 1015 * CPU may win the "own_req" race so that inet_ehash_insert() fails. 1016 */ 1017 if (nreq) { 1018 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE); 1019 no_ownership: 1020 reqsk_migrate_reset(nreq); 1021 reqsk_queue_removed(queue, nreq); 1022 __reqsk_free(nreq); 1023 } 1024 1025 drop: 1026 inet_csk_reqsk_queue_drop_and_put(oreq->rsk_listener, oreq); 1027 } 1028 1029 static void reqsk_queue_hash_req(struct request_sock *req, 1030 unsigned long timeout) 1031 { 1032 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED); 1033 mod_timer(&req->rsk_timer, jiffies + timeout); 1034 1035 inet_ehash_insert(req_to_sk(req), NULL, NULL); 1036 /* before letting lookups find us, make sure all req fields 1037 * are committed to memory and refcnt initialized. 1038 */ 1039 smp_wmb(); 1040 refcount_set(&req->rsk_refcnt, 2 + 1); 1041 } 1042 1043 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, 1044 unsigned long timeout) 1045 { 1046 reqsk_queue_hash_req(req, timeout); 1047 inet_csk_reqsk_queue_added(sk); 1048 } 1049 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); 1050 1051 static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk, 1052 const gfp_t priority) 1053 { 1054 struct inet_connection_sock *icsk = inet_csk(newsk); 1055 1056 if (!icsk->icsk_ulp_ops) 1057 return; 1058 1059 if (icsk->icsk_ulp_ops->clone) 1060 icsk->icsk_ulp_ops->clone(req, newsk, priority); 1061 } 1062 1063 /** 1064 * inet_csk_clone_lock - clone an inet socket, and lock its clone 1065 * @sk: the socket to clone 1066 * @req: request_sock 1067 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc) 1068 * 1069 * Caller must unlock socket even in error path (bh_unlock_sock(newsk)) 1070 */ 1071 struct sock *inet_csk_clone_lock(const struct sock *sk, 1072 const struct request_sock *req, 1073 const gfp_t priority) 1074 { 1075 struct sock *newsk = sk_clone_lock(sk, priority); 1076 1077 if (newsk) { 1078 struct inet_connection_sock *newicsk = inet_csk(newsk); 1079 1080 inet_sk_set_state(newsk, TCP_SYN_RECV); 1081 newicsk->icsk_bind_hash = NULL; 1082 newicsk->icsk_bind2_hash = NULL; 1083 1084 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port; 1085 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num; 1086 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num); 1087 1088 /* listeners have SOCK_RCU_FREE, not the children */ 1089 sock_reset_flag(newsk, SOCK_RCU_FREE); 1090 1091 inet_sk(newsk)->mc_list = NULL; 1092 1093 newsk->sk_mark = inet_rsk(req)->ir_mark; 1094 atomic64_set(&newsk->sk_cookie, 1095 atomic64_read(&inet_rsk(req)->ir_cookie)); 1096 1097 newicsk->icsk_retransmits = 0; 1098 newicsk->icsk_backoff = 0; 1099 newicsk->icsk_probes_out = 0; 1100 newicsk->icsk_probes_tstamp = 0; 1101 1102 /* Deinitialize accept_queue to trap illegal accesses. */ 1103 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue)); 1104 1105 inet_clone_ulp(req, newsk, priority); 1106 1107 security_inet_csk_clone(newsk, req); 1108 } 1109 return newsk; 1110 } 1111 EXPORT_SYMBOL_GPL(inet_csk_clone_lock); 1112 1113 /* 1114 * At this point, there should be no process reference to this 1115 * socket, and thus no user references at all. Therefore we 1116 * can assume the socket waitqueue is inactive and nobody will 1117 * try to jump onto it. 1118 */ 1119 void inet_csk_destroy_sock(struct sock *sk) 1120 { 1121 WARN_ON(sk->sk_state != TCP_CLOSE); 1122 WARN_ON(!sock_flag(sk, SOCK_DEAD)); 1123 1124 /* It cannot be in hash table! */ 1125 WARN_ON(!sk_unhashed(sk)); 1126 1127 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */ 1128 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash); 1129 1130 sk->sk_prot->destroy(sk); 1131 1132 sk_stream_kill_queues(sk); 1133 1134 xfrm_sk_free_policy(sk); 1135 1136 sk_refcnt_debug_release(sk); 1137 1138 this_cpu_dec(*sk->sk_prot->orphan_count); 1139 1140 sock_put(sk); 1141 } 1142 EXPORT_SYMBOL(inet_csk_destroy_sock); 1143 1144 /* This function allows to force a closure of a socket after the call to 1145 * tcp/dccp_create_openreq_child(). 1146 */ 1147 void inet_csk_prepare_forced_close(struct sock *sk) 1148 __releases(&sk->sk_lock.slock) 1149 { 1150 /* sk_clone_lock locked the socket and set refcnt to 2 */ 1151 bh_unlock_sock(sk); 1152 sock_put(sk); 1153 inet_csk_prepare_for_destroy_sock(sk); 1154 inet_sk(sk)->inet_num = 0; 1155 } 1156 EXPORT_SYMBOL(inet_csk_prepare_forced_close); 1157 1158 int inet_csk_listen_start(struct sock *sk) 1159 { 1160 struct inet_connection_sock *icsk = inet_csk(sk); 1161 struct inet_sock *inet = inet_sk(sk); 1162 int err = -EADDRINUSE; 1163 1164 reqsk_queue_alloc(&icsk->icsk_accept_queue); 1165 1166 sk->sk_ack_backlog = 0; 1167 inet_csk_delack_init(sk); 1168 1169 if (sk->sk_txrehash == SOCK_TXREHASH_DEFAULT) 1170 sk->sk_txrehash = READ_ONCE(sock_net(sk)->core.sysctl_txrehash); 1171 1172 /* There is race window here: we announce ourselves listening, 1173 * but this transition is still not validated by get_port(). 1174 * It is OK, because this socket enters to hash table only 1175 * after validation is complete. 1176 */ 1177 inet_sk_state_store(sk, TCP_LISTEN); 1178 if (!sk->sk_prot->get_port(sk, inet->inet_num)) { 1179 inet->inet_sport = htons(inet->inet_num); 1180 1181 sk_dst_reset(sk); 1182 err = sk->sk_prot->hash(sk); 1183 1184 if (likely(!err)) 1185 return 0; 1186 } 1187 1188 inet_sk_set_state(sk, TCP_CLOSE); 1189 return err; 1190 } 1191 EXPORT_SYMBOL_GPL(inet_csk_listen_start); 1192 1193 static void inet_child_forget(struct sock *sk, struct request_sock *req, 1194 struct sock *child) 1195 { 1196 sk->sk_prot->disconnect(child, O_NONBLOCK); 1197 1198 sock_orphan(child); 1199 1200 this_cpu_inc(*sk->sk_prot->orphan_count); 1201 1202 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) { 1203 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req); 1204 BUG_ON(sk != req->rsk_listener); 1205 1206 /* Paranoid, to prevent race condition if 1207 * an inbound pkt destined for child is 1208 * blocked by sock lock in tcp_v4_rcv(). 1209 * Also to satisfy an assertion in 1210 * tcp_v4_destroy_sock(). 1211 */ 1212 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL); 1213 } 1214 inet_csk_destroy_sock(child); 1215 } 1216 1217 struct sock *inet_csk_reqsk_queue_add(struct sock *sk, 1218 struct request_sock *req, 1219 struct sock *child) 1220 { 1221 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; 1222 1223 spin_lock(&queue->rskq_lock); 1224 if (unlikely(sk->sk_state != TCP_LISTEN)) { 1225 inet_child_forget(sk, req, child); 1226 child = NULL; 1227 } else { 1228 req->sk = child; 1229 req->dl_next = NULL; 1230 if (queue->rskq_accept_head == NULL) 1231 WRITE_ONCE(queue->rskq_accept_head, req); 1232 else 1233 queue->rskq_accept_tail->dl_next = req; 1234 queue->rskq_accept_tail = req; 1235 sk_acceptq_added(sk); 1236 } 1237 spin_unlock(&queue->rskq_lock); 1238 return child; 1239 } 1240 EXPORT_SYMBOL(inet_csk_reqsk_queue_add); 1241 1242 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child, 1243 struct request_sock *req, bool own_req) 1244 { 1245 if (own_req) { 1246 inet_csk_reqsk_queue_drop(req->rsk_listener, req); 1247 reqsk_queue_removed(&inet_csk(req->rsk_listener)->icsk_accept_queue, req); 1248 1249 if (sk != req->rsk_listener) { 1250 /* another listening sk has been selected, 1251 * migrate the req to it. 1252 */ 1253 struct request_sock *nreq; 1254 1255 /* hold a refcnt for the nreq->rsk_listener 1256 * which is assigned in inet_reqsk_clone() 1257 */ 1258 sock_hold(sk); 1259 nreq = inet_reqsk_clone(req, sk); 1260 if (!nreq) { 1261 inet_child_forget(sk, req, child); 1262 goto child_put; 1263 } 1264 1265 refcount_set(&nreq->rsk_refcnt, 1); 1266 if (inet_csk_reqsk_queue_add(sk, nreq, child)) { 1267 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS); 1268 reqsk_migrate_reset(req); 1269 reqsk_put(req); 1270 return child; 1271 } 1272 1273 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE); 1274 reqsk_migrate_reset(nreq); 1275 __reqsk_free(nreq); 1276 } else if (inet_csk_reqsk_queue_add(sk, req, child)) { 1277 return child; 1278 } 1279 } 1280 /* Too bad, another child took ownership of the request, undo. */ 1281 child_put: 1282 bh_unlock_sock(child); 1283 sock_put(child); 1284 return NULL; 1285 } 1286 EXPORT_SYMBOL(inet_csk_complete_hashdance); 1287 1288 /* 1289 * This routine closes sockets which have been at least partially 1290 * opened, but not yet accepted. 1291 */ 1292 void inet_csk_listen_stop(struct sock *sk) 1293 { 1294 struct inet_connection_sock *icsk = inet_csk(sk); 1295 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 1296 struct request_sock *next, *req; 1297 1298 /* Following specs, it would be better either to send FIN 1299 * (and enter FIN-WAIT-1, it is normal close) 1300 * or to send active reset (abort). 1301 * Certainly, it is pretty dangerous while synflood, but it is 1302 * bad justification for our negligence 8) 1303 * To be honest, we are not able to make either 1304 * of the variants now. --ANK 1305 */ 1306 while ((req = reqsk_queue_remove(queue, sk)) != NULL) { 1307 struct sock *child = req->sk, *nsk; 1308 struct request_sock *nreq; 1309 1310 local_bh_disable(); 1311 bh_lock_sock(child); 1312 WARN_ON(sock_owned_by_user(child)); 1313 sock_hold(child); 1314 1315 nsk = reuseport_migrate_sock(sk, child, NULL); 1316 if (nsk) { 1317 nreq = inet_reqsk_clone(req, nsk); 1318 if (nreq) { 1319 refcount_set(&nreq->rsk_refcnt, 1); 1320 1321 if (inet_csk_reqsk_queue_add(nsk, nreq, child)) { 1322 __NET_INC_STATS(sock_net(nsk), 1323 LINUX_MIB_TCPMIGRATEREQSUCCESS); 1324 reqsk_migrate_reset(req); 1325 } else { 1326 __NET_INC_STATS(sock_net(nsk), 1327 LINUX_MIB_TCPMIGRATEREQFAILURE); 1328 reqsk_migrate_reset(nreq); 1329 __reqsk_free(nreq); 1330 } 1331 1332 /* inet_csk_reqsk_queue_add() has already 1333 * called inet_child_forget() on failure case. 1334 */ 1335 goto skip_child_forget; 1336 } 1337 } 1338 1339 inet_child_forget(sk, req, child); 1340 skip_child_forget: 1341 reqsk_put(req); 1342 bh_unlock_sock(child); 1343 local_bh_enable(); 1344 sock_put(child); 1345 1346 cond_resched(); 1347 } 1348 if (queue->fastopenq.rskq_rst_head) { 1349 /* Free all the reqs queued in rskq_rst_head. */ 1350 spin_lock_bh(&queue->fastopenq.lock); 1351 req = queue->fastopenq.rskq_rst_head; 1352 queue->fastopenq.rskq_rst_head = NULL; 1353 spin_unlock_bh(&queue->fastopenq.lock); 1354 while (req != NULL) { 1355 next = req->dl_next; 1356 reqsk_put(req); 1357 req = next; 1358 } 1359 } 1360 WARN_ON_ONCE(sk->sk_ack_backlog); 1361 } 1362 EXPORT_SYMBOL_GPL(inet_csk_listen_stop); 1363 1364 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr) 1365 { 1366 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr; 1367 const struct inet_sock *inet = inet_sk(sk); 1368 1369 sin->sin_family = AF_INET; 1370 sin->sin_addr.s_addr = inet->inet_daddr; 1371 sin->sin_port = inet->inet_dport; 1372 } 1373 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr); 1374 1375 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl) 1376 { 1377 const struct inet_sock *inet = inet_sk(sk); 1378 const struct ip_options_rcu *inet_opt; 1379 __be32 daddr = inet->inet_daddr; 1380 struct flowi4 *fl4; 1381 struct rtable *rt; 1382 1383 rcu_read_lock(); 1384 inet_opt = rcu_dereference(inet->inet_opt); 1385 if (inet_opt && inet_opt->opt.srr) 1386 daddr = inet_opt->opt.faddr; 1387 fl4 = &fl->u.ip4; 1388 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, 1389 inet->inet_saddr, inet->inet_dport, 1390 inet->inet_sport, sk->sk_protocol, 1391 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if); 1392 if (IS_ERR(rt)) 1393 rt = NULL; 1394 if (rt) 1395 sk_setup_caps(sk, &rt->dst); 1396 rcu_read_unlock(); 1397 1398 return &rt->dst; 1399 } 1400 1401 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu) 1402 { 1403 struct dst_entry *dst = __sk_dst_check(sk, 0); 1404 struct inet_sock *inet = inet_sk(sk); 1405 1406 if (!dst) { 1407 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 1408 if (!dst) 1409 goto out; 1410 } 1411 dst->ops->update_pmtu(dst, sk, NULL, mtu, true); 1412 1413 dst = __sk_dst_check(sk, 0); 1414 if (!dst) 1415 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 1416 out: 1417 return dst; 1418 } 1419 EXPORT_SYMBOL_GPL(inet_csk_update_pmtu); 1420