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 */ 34static 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 */ 78static 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 91bool 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} 109EXPORT_SYMBOL(inet_rcv_saddr_equal); 110 111bool 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/** 121 * inet_sk_get_local_port_range - fetch ephemeral ports range 122 * @sk: socket 123 * @low: pointer to low port 124 * @high: pointer to high port 125 * 126 * Fetch netns port range (/proc/sys/net/ipv4/ip_local_port_range) 127 * Range can be overridden if socket got IP_LOCAL_PORT_RANGE option. 128 * Returns true if IP_LOCAL_PORT_RANGE was set on this socket. 129 */ 130bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high) 131{ 132 int lo, hi, sk_lo, sk_hi; 133 bool local_range = false; 134 u32 sk_range; 135 136 inet_get_local_port_range(sock_net(sk), &lo, &hi); 137 138 sk_range = READ_ONCE(inet_sk(sk)->local_port_range); 139 if (unlikely(sk_range)) { 140 sk_lo = sk_range & 0xffff; 141 sk_hi = sk_range >> 16; 142 143 if (lo <= sk_lo && sk_lo <= hi) 144 lo = sk_lo; 145 if (lo <= sk_hi && sk_hi <= hi) 146 hi = sk_hi; 147 local_range = true; 148 } 149 150 *low = lo; 151 *high = hi; 152 return local_range; 153} 154EXPORT_SYMBOL(inet_sk_get_local_port_range); 155 156static bool inet_use_bhash2_on_bind(const struct sock *sk) 157{ 158#if IS_ENABLED(CONFIG_IPV6) 159 if (sk->sk_family == AF_INET6) { 160 int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr); 161 162 if (addr_type == IPV6_ADDR_ANY) 163 return false; 164 165 if (addr_type != IPV6_ADDR_MAPPED) 166 return true; 167 } 168#endif 169 return sk->sk_rcv_saddr != htonl(INADDR_ANY); 170} 171 172static bool inet_bind_conflict(const struct sock *sk, struct sock *sk2, 173 kuid_t sk_uid, bool relax, 174 bool reuseport_cb_ok, bool reuseport_ok) 175{ 176 int bound_dev_if2; 177 178 if (sk == sk2) 179 return false; 180 181 bound_dev_if2 = READ_ONCE(sk2->sk_bound_dev_if); 182 183 if (!sk->sk_bound_dev_if || !bound_dev_if2 || 184 sk->sk_bound_dev_if == bound_dev_if2) { 185 if (sk->sk_reuse && sk2->sk_reuse && 186 sk2->sk_state != TCP_LISTEN) { 187 if (!relax || (!reuseport_ok && sk->sk_reuseport && 188 sk2->sk_reuseport && reuseport_cb_ok && 189 (sk2->sk_state == TCP_TIME_WAIT || 190 uid_eq(sk_uid, sock_i_uid(sk2))))) 191 return true; 192 } else if (!reuseport_ok || !sk->sk_reuseport || 193 !sk2->sk_reuseport || !reuseport_cb_ok || 194 (sk2->sk_state != TCP_TIME_WAIT && 195 !uid_eq(sk_uid, sock_i_uid(sk2)))) { 196 return true; 197 } 198 } 199 return false; 200} 201 202static bool __inet_bhash2_conflict(const struct sock *sk, struct sock *sk2, 203 kuid_t sk_uid, bool relax, 204 bool reuseport_cb_ok, bool reuseport_ok) 205{ 206 if (ipv6_only_sock(sk2)) { 207 if (sk->sk_family == AF_INET) 208 return false; 209 210#if IS_ENABLED(CONFIG_IPV6) 211 if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) 212 return false; 213#endif 214 } 215 216 return inet_bind_conflict(sk, sk2, sk_uid, relax, 217 reuseport_cb_ok, reuseport_ok); 218} 219 220static bool inet_bhash2_conflict(const struct sock *sk, 221 const struct inet_bind2_bucket *tb2, 222 kuid_t sk_uid, 223 bool relax, bool reuseport_cb_ok, 224 bool reuseport_ok) 225{ 226 struct sock *sk2; 227 228 sk_for_each_bound(sk2, &tb2->owners) { 229 if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax, 230 reuseport_cb_ok, reuseport_ok)) 231 return true; 232 } 233 234 return false; 235} 236 237#define sk_for_each_bound_bhash(__sk, __tb2, __tb) \ 238 hlist_for_each_entry(__tb2, &(__tb)->bhash2, bhash_node) \ 239 sk_for_each_bound(sk2, &(__tb2)->owners) 240 241/* This should be called only when the tb and tb2 hashbuckets' locks are held */ 242static int inet_csk_bind_conflict(const struct sock *sk, 243 const struct inet_bind_bucket *tb, 244 const struct inet_bind2_bucket *tb2, /* may be null */ 245 bool relax, bool reuseport_ok) 246{ 247 kuid_t uid = sock_i_uid((struct sock *)sk); 248 struct sock_reuseport *reuseport_cb; 249 bool reuseport_cb_ok; 250 struct sock *sk2; 251 252 rcu_read_lock(); 253 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb); 254 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */ 255 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks); 256 rcu_read_unlock(); 257 258 /* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if 259 * ipv4) should have been checked already. We need to do these two 260 * checks separately because their spinlocks have to be acquired/released 261 * independently of each other, to prevent possible deadlocks 262 */ 263 if (inet_use_bhash2_on_bind(sk)) 264 return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, 265 reuseport_cb_ok, reuseport_ok); 266 267 /* Unlike other sk lookup places we do not check 268 * for sk_net here, since _all_ the socks listed 269 * in tb->owners and tb2->owners list belong 270 * to the same net - the one this bucket belongs to. 271 */ 272 sk_for_each_bound_bhash(sk2, tb2, tb) { 273 if (!inet_bind_conflict(sk, sk2, uid, relax, reuseport_cb_ok, reuseport_ok)) 274 continue; 275 276 if (inet_rcv_saddr_equal(sk, sk2, true)) 277 return true; 278 } 279 280 return false; 281} 282 283/* Determine if there is a bind conflict with an existing IPV6_ADDR_ANY (if ipv6) or 284 * INADDR_ANY (if ipv4) socket. 285 * 286 * Caller must hold bhash hashbucket lock with local bh disabled, to protect 287 * against concurrent binds on the port for addr any 288 */ 289static bool inet_bhash2_addr_any_conflict(const struct sock *sk, int port, int l3mdev, 290 bool relax, bool reuseport_ok) 291{ 292 kuid_t uid = sock_i_uid((struct sock *)sk); 293 const struct net *net = sock_net(sk); 294 struct sock_reuseport *reuseport_cb; 295 struct inet_bind_hashbucket *head2; 296 struct inet_bind2_bucket *tb2; 297 bool conflict = false; 298 bool reuseport_cb_ok; 299 300 rcu_read_lock(); 301 reuseport_cb = rcu_dereference(sk->sk_reuseport_cb); 302 /* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */ 303 reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks); 304 rcu_read_unlock(); 305 306 head2 = inet_bhash2_addr_any_hashbucket(sk, net, port); 307 308 spin_lock(&head2->lock); 309 310 inet_bind_bucket_for_each(tb2, &head2->chain) { 311 if (!inet_bind2_bucket_match_addr_any(tb2, net, port, l3mdev, sk)) 312 continue; 313 314 if (!inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok, reuseport_ok)) 315 continue; 316 317 conflict = true; 318 break; 319 } 320 321 spin_unlock(&head2->lock); 322 323 return conflict; 324} 325 326/* 327 * Find an open port number for the socket. Returns with the 328 * inet_bind_hashbucket locks held if successful. 329 */ 330static struct inet_bind_hashbucket * 331inet_csk_find_open_port(const struct sock *sk, struct inet_bind_bucket **tb_ret, 332 struct inet_bind2_bucket **tb2_ret, 333 struct inet_bind_hashbucket **head2_ret, int *port_ret) 334{ 335 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk); 336 int i, low, high, attempt_half, port, l3mdev; 337 struct inet_bind_hashbucket *head, *head2; 338 struct net *net = sock_net(sk); 339 struct inet_bind2_bucket *tb2; 340 struct inet_bind_bucket *tb; 341 u32 remaining, offset; 342 bool relax = false; 343 344 l3mdev = inet_sk_bound_l3mdev(sk); 345ports_exhausted: 346 attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0; 347other_half_scan: 348 inet_sk_get_local_port_range(sk, &low, &high); 349 high++; /* [32768, 60999] -> [32768, 61000[ */ 350 if (high - low < 4) 351 attempt_half = 0; 352 if (attempt_half) { 353 int half = low + (((high - low) >> 2) << 1); 354 355 if (attempt_half == 1) 356 high = half; 357 else 358 low = half; 359 } 360 remaining = high - low; 361 if (likely(remaining > 1)) 362 remaining &= ~1U; 363 364 offset = get_random_u32_below(remaining); 365 /* __inet_hash_connect() favors ports having @low parity 366 * We do the opposite to not pollute connect() users. 367 */ 368 offset |= 1U; 369 370other_parity_scan: 371 port = low + offset; 372 for (i = 0; i < remaining; i += 2, port += 2) { 373 if (unlikely(port >= high)) 374 port -= remaining; 375 if (inet_is_local_reserved_port(net, port)) 376 continue; 377 head = &hinfo->bhash[inet_bhashfn(net, port, 378 hinfo->bhash_size)]; 379 spin_lock_bh(&head->lock); 380 if (inet_use_bhash2_on_bind(sk)) { 381 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, relax, false)) 382 goto next_port; 383 } 384 385 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port); 386 spin_lock(&head2->lock); 387 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk); 388 inet_bind_bucket_for_each(tb, &head->chain) 389 if (inet_bind_bucket_match(tb, net, port, l3mdev)) { 390 if (!inet_csk_bind_conflict(sk, tb, tb2, 391 relax, false)) 392 goto success; 393 spin_unlock(&head2->lock); 394 goto next_port; 395 } 396 tb = NULL; 397 goto success; 398next_port: 399 spin_unlock_bh(&head->lock); 400 cond_resched(); 401 } 402 403 offset--; 404 if (!(offset & 1)) 405 goto other_parity_scan; 406 407 if (attempt_half == 1) { 408 /* OK we now try the upper half of the range */ 409 attempt_half = 2; 410 goto other_half_scan; 411 } 412 413 if (READ_ONCE(net->ipv4.sysctl_ip_autobind_reuse) && !relax) { 414 /* We still have a chance to connect to different destinations */ 415 relax = true; 416 goto ports_exhausted; 417 } 418 return NULL; 419success: 420 *port_ret = port; 421 *tb_ret = tb; 422 *tb2_ret = tb2; 423 *head2_ret = head2; 424 return head; 425} 426 427static inline int sk_reuseport_match(struct inet_bind_bucket *tb, 428 struct sock *sk) 429{ 430 kuid_t uid = sock_i_uid(sk); 431 432 if (tb->fastreuseport <= 0) 433 return 0; 434 if (!sk->sk_reuseport) 435 return 0; 436 if (rcu_access_pointer(sk->sk_reuseport_cb)) 437 return 0; 438 if (!uid_eq(tb->fastuid, uid)) 439 return 0; 440 /* We only need to check the rcv_saddr if this tb was once marked 441 * without fastreuseport and then was reset, as we can only know that 442 * the fast_*rcv_saddr doesn't have any conflicts with the socks on the 443 * owners list. 444 */ 445 if (tb->fastreuseport == FASTREUSEPORT_ANY) 446 return 1; 447#if IS_ENABLED(CONFIG_IPV6) 448 if (tb->fast_sk_family == AF_INET6) 449 return ipv6_rcv_saddr_equal(&tb->fast_v6_rcv_saddr, 450 inet6_rcv_saddr(sk), 451 tb->fast_rcv_saddr, 452 sk->sk_rcv_saddr, 453 tb->fast_ipv6_only, 454 ipv6_only_sock(sk), true, false); 455#endif 456 return ipv4_rcv_saddr_equal(tb->fast_rcv_saddr, sk->sk_rcv_saddr, 457 ipv6_only_sock(sk), true, false); 458} 459 460void inet_csk_update_fastreuse(struct inet_bind_bucket *tb, 461 struct sock *sk) 462{ 463 kuid_t uid = sock_i_uid(sk); 464 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; 465 466 if (hlist_empty(&tb->bhash2)) { 467 tb->fastreuse = reuse; 468 if (sk->sk_reuseport) { 469 tb->fastreuseport = FASTREUSEPORT_ANY; 470 tb->fastuid = uid; 471 tb->fast_rcv_saddr = sk->sk_rcv_saddr; 472 tb->fast_ipv6_only = ipv6_only_sock(sk); 473 tb->fast_sk_family = sk->sk_family; 474#if IS_ENABLED(CONFIG_IPV6) 475 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; 476#endif 477 } else { 478 tb->fastreuseport = 0; 479 } 480 } else { 481 if (!reuse) 482 tb->fastreuse = 0; 483 if (sk->sk_reuseport) { 484 /* We didn't match or we don't have fastreuseport set on 485 * the tb, but we have sk_reuseport set on this socket 486 * and we know that there are no bind conflicts with 487 * this socket in this tb, so reset our tb's reuseport 488 * settings so that any subsequent sockets that match 489 * our current socket will be put on the fast path. 490 * 491 * If we reset we need to set FASTREUSEPORT_STRICT so we 492 * do extra checking for all subsequent sk_reuseport 493 * socks. 494 */ 495 if (!sk_reuseport_match(tb, sk)) { 496 tb->fastreuseport = FASTREUSEPORT_STRICT; 497 tb->fastuid = uid; 498 tb->fast_rcv_saddr = sk->sk_rcv_saddr; 499 tb->fast_ipv6_only = ipv6_only_sock(sk); 500 tb->fast_sk_family = sk->sk_family; 501#if IS_ENABLED(CONFIG_IPV6) 502 tb->fast_v6_rcv_saddr = sk->sk_v6_rcv_saddr; 503#endif 504 } 505 } else { 506 tb->fastreuseport = 0; 507 } 508 } 509} 510 511/* Obtain a reference to a local port for the given sock, 512 * if snum is zero it means select any available local port. 513 * We try to allocate an odd port (and leave even ports for connect()) 514 */ 515int inet_csk_get_port(struct sock *sk, unsigned short snum) 516{ 517 struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk); 518 bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN; 519 bool found_port = false, check_bind_conflict = true; 520 bool bhash_created = false, bhash2_created = false; 521 int ret = -EADDRINUSE, port = snum, l3mdev; 522 struct inet_bind_hashbucket *head, *head2; 523 struct inet_bind2_bucket *tb2 = NULL; 524 struct inet_bind_bucket *tb = NULL; 525 bool head2_lock_acquired = false; 526 struct net *net = sock_net(sk); 527 528 l3mdev = inet_sk_bound_l3mdev(sk); 529 530 if (!port) { 531 head = inet_csk_find_open_port(sk, &tb, &tb2, &head2, &port); 532 if (!head) 533 return ret; 534 535 head2_lock_acquired = true; 536 537 if (tb && tb2) 538 goto success; 539 found_port = true; 540 } else { 541 head = &hinfo->bhash[inet_bhashfn(net, port, 542 hinfo->bhash_size)]; 543 spin_lock_bh(&head->lock); 544 inet_bind_bucket_for_each(tb, &head->chain) 545 if (inet_bind_bucket_match(tb, net, port, l3mdev)) 546 break; 547 } 548 549 if (!tb) { 550 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net, 551 head, port, l3mdev); 552 if (!tb) 553 goto fail_unlock; 554 bhash_created = true; 555 } 556 557 if (!found_port) { 558 if (!hlist_empty(&tb->bhash2)) { 559 if (sk->sk_reuse == SK_FORCE_REUSE || 560 (tb->fastreuse > 0 && reuse) || 561 sk_reuseport_match(tb, sk)) 562 check_bind_conflict = false; 563 } 564 565 if (check_bind_conflict && inet_use_bhash2_on_bind(sk)) { 566 if (inet_bhash2_addr_any_conflict(sk, port, l3mdev, true, true)) 567 goto fail_unlock; 568 } 569 570 head2 = inet_bhashfn_portaddr(hinfo, sk, net, port); 571 spin_lock(&head2->lock); 572 head2_lock_acquired = true; 573 tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk); 574 } 575 576 if (!tb2) { 577 tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep, 578 net, head2, tb, sk); 579 if (!tb2) 580 goto fail_unlock; 581 bhash2_created = true; 582 } 583 584 if (!found_port && check_bind_conflict) { 585 if (inet_csk_bind_conflict(sk, tb, tb2, true, true)) 586 goto fail_unlock; 587 } 588 589success: 590 inet_csk_update_fastreuse(tb, sk); 591 592 if (!inet_csk(sk)->icsk_bind_hash) 593 inet_bind_hash(sk, tb, tb2, port); 594 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); 595 WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2); 596 ret = 0; 597 598fail_unlock: 599 if (ret) { 600 if (bhash2_created) 601 inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep, tb2); 602 if (bhash_created) 603 inet_bind_bucket_destroy(hinfo->bind_bucket_cachep, tb); 604 } 605 if (head2_lock_acquired) 606 spin_unlock(&head2->lock); 607 spin_unlock_bh(&head->lock); 608 return ret; 609} 610EXPORT_SYMBOL_GPL(inet_csk_get_port); 611 612/* 613 * Wait for an incoming connection, avoid race conditions. This must be called 614 * with the socket locked. 615 */ 616static int inet_csk_wait_for_connect(struct sock *sk, long timeo) 617{ 618 struct inet_connection_sock *icsk = inet_csk(sk); 619 DEFINE_WAIT(wait); 620 int err; 621 622 /* 623 * True wake-one mechanism for incoming connections: only 624 * one process gets woken up, not the 'whole herd'. 625 * Since we do not 'race & poll' for established sockets 626 * anymore, the common case will execute the loop only once. 627 * 628 * Subtle issue: "add_wait_queue_exclusive()" will be added 629 * after any current non-exclusive waiters, and we know that 630 * it will always _stay_ after any new non-exclusive waiters 631 * because all non-exclusive waiters are added at the 632 * beginning of the wait-queue. As such, it's ok to "drop" 633 * our exclusiveness temporarily when we get woken up without 634 * having to remove and re-insert us on the wait queue. 635 */ 636 for (;;) { 637 prepare_to_wait_exclusive(sk_sleep(sk), &wait, 638 TASK_INTERRUPTIBLE); 639 release_sock(sk); 640 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) 641 timeo = schedule_timeout(timeo); 642 sched_annotate_sleep(); 643 lock_sock(sk); 644 err = 0; 645 if (!reqsk_queue_empty(&icsk->icsk_accept_queue)) 646 break; 647 err = -EINVAL; 648 if (sk->sk_state != TCP_LISTEN) 649 break; 650 err = sock_intr_errno(timeo); 651 if (signal_pending(current)) 652 break; 653 err = -EAGAIN; 654 if (!timeo) 655 break; 656 } 657 finish_wait(sk_sleep(sk), &wait); 658 return err; 659} 660 661/* 662 * This will accept the next outstanding connection. 663 */ 664struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern) 665{ 666 struct inet_connection_sock *icsk = inet_csk(sk); 667 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 668 struct request_sock *req; 669 struct sock *newsk; 670 int error; 671 672 lock_sock(sk); 673 674 /* We need to make sure that this socket is listening, 675 * and that it has something pending. 676 */ 677 error = -EINVAL; 678 if (sk->sk_state != TCP_LISTEN) 679 goto out_err; 680 681 /* Find already established connection */ 682 if (reqsk_queue_empty(queue)) { 683 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK); 684 685 /* If this is a non blocking socket don't sleep */ 686 error = -EAGAIN; 687 if (!timeo) 688 goto out_err; 689 690 error = inet_csk_wait_for_connect(sk, timeo); 691 if (error) 692 goto out_err; 693 } 694 req = reqsk_queue_remove(queue, sk); 695 newsk = req->sk; 696 697 if (sk->sk_protocol == IPPROTO_TCP && 698 tcp_rsk(req)->tfo_listener) { 699 spin_lock_bh(&queue->fastopenq.lock); 700 if (tcp_rsk(req)->tfo_listener) { 701 /* We are still waiting for the final ACK from 3WHS 702 * so can't free req now. Instead, we set req->sk to 703 * NULL to signify that the child socket is taken 704 * so reqsk_fastopen_remove() will free the req 705 * when 3WHS finishes (or is aborted). 706 */ 707 req->sk = NULL; 708 req = NULL; 709 } 710 spin_unlock_bh(&queue->fastopenq.lock); 711 } 712 713out: 714 release_sock(sk); 715 if (newsk && mem_cgroup_sockets_enabled) { 716 int amt = 0; 717 718 /* atomically get the memory usage, set and charge the 719 * newsk->sk_memcg. 720 */ 721 lock_sock(newsk); 722 723 mem_cgroup_sk_alloc(newsk); 724 if (newsk->sk_memcg) { 725 /* The socket has not been accepted yet, no need 726 * to look at newsk->sk_wmem_queued. 727 */ 728 amt = sk_mem_pages(newsk->sk_forward_alloc + 729 atomic_read(&newsk->sk_rmem_alloc)); 730 } 731 732 if (amt) 733 mem_cgroup_charge_skmem(newsk->sk_memcg, amt, 734 GFP_KERNEL | __GFP_NOFAIL); 735 736 release_sock(newsk); 737 } 738 if (req) 739 reqsk_put(req); 740 741 if (newsk) 742 inet_init_csk_locks(newsk); 743 744 return newsk; 745out_err: 746 newsk = NULL; 747 req = NULL; 748 *err = error; 749 goto out; 750} 751EXPORT_SYMBOL(inet_csk_accept); 752 753/* 754 * Using different timers for retransmit, delayed acks and probes 755 * We may wish use just one timer maintaining a list of expire jiffies 756 * to optimize. 757 */ 758void inet_csk_init_xmit_timers(struct sock *sk, 759 void (*retransmit_handler)(struct timer_list *t), 760 void (*delack_handler)(struct timer_list *t), 761 void (*keepalive_handler)(struct timer_list *t)) 762{ 763 struct inet_connection_sock *icsk = inet_csk(sk); 764 765 timer_setup(&icsk->icsk_retransmit_timer, retransmit_handler, 0); 766 timer_setup(&icsk->icsk_delack_timer, delack_handler, 0); 767 timer_setup(&sk->sk_timer, keepalive_handler, 0); 768 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 769} 770EXPORT_SYMBOL(inet_csk_init_xmit_timers); 771 772void inet_csk_clear_xmit_timers(struct sock *sk) 773{ 774 struct inet_connection_sock *icsk = inet_csk(sk); 775 776 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 777 778 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 779 sk_stop_timer(sk, &icsk->icsk_delack_timer); 780 sk_stop_timer(sk, &sk->sk_timer); 781} 782EXPORT_SYMBOL(inet_csk_clear_xmit_timers); 783 784void inet_csk_clear_xmit_timers_sync(struct sock *sk) 785{ 786 struct inet_connection_sock *icsk = inet_csk(sk); 787 788 /* ongoing timer handlers need to acquire socket lock. */ 789 sock_not_owned_by_me(sk); 790 791 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 792 793 sk_stop_timer_sync(sk, &icsk->icsk_retransmit_timer); 794 sk_stop_timer_sync(sk, &icsk->icsk_delack_timer); 795 sk_stop_timer_sync(sk, &sk->sk_timer); 796} 797 798void inet_csk_delete_keepalive_timer(struct sock *sk) 799{ 800 sk_stop_timer(sk, &sk->sk_timer); 801} 802EXPORT_SYMBOL(inet_csk_delete_keepalive_timer); 803 804void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) 805{ 806 sk_reset_timer(sk, &sk->sk_timer, jiffies + len); 807} 808EXPORT_SYMBOL(inet_csk_reset_keepalive_timer); 809 810struct dst_entry *inet_csk_route_req(const struct sock *sk, 811 struct flowi4 *fl4, 812 const struct request_sock *req) 813{ 814 const struct inet_request_sock *ireq = inet_rsk(req); 815 struct net *net = read_pnet(&ireq->ireq_net); 816 struct ip_options_rcu *opt; 817 struct rtable *rt; 818 819 rcu_read_lock(); 820 opt = rcu_dereference(ireq->ireq_opt); 821 822 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark, 823 ip_sock_rt_tos(sk), ip_sock_rt_scope(sk), 824 sk->sk_protocol, inet_sk_flowi_flags(sk), 825 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, 826 ireq->ir_loc_addr, ireq->ir_rmt_port, 827 htons(ireq->ir_num), sk->sk_uid); 828 security_req_classify_flow(req, flowi4_to_flowi_common(fl4)); 829 rt = ip_route_output_flow(net, fl4, sk); 830 if (IS_ERR(rt)) 831 goto no_route; 832 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 833 goto route_err; 834 rcu_read_unlock(); 835 return &rt->dst; 836 837route_err: 838 ip_rt_put(rt); 839no_route: 840 rcu_read_unlock(); 841 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); 842 return NULL; 843} 844EXPORT_SYMBOL_GPL(inet_csk_route_req); 845 846struct dst_entry *inet_csk_route_child_sock(const struct sock *sk, 847 struct sock *newsk, 848 const struct request_sock *req) 849{ 850 const struct inet_request_sock *ireq = inet_rsk(req); 851 struct net *net = read_pnet(&ireq->ireq_net); 852 struct inet_sock *newinet = inet_sk(newsk); 853 struct ip_options_rcu *opt; 854 struct flowi4 *fl4; 855 struct rtable *rt; 856 857 opt = rcu_dereference(ireq->ireq_opt); 858 fl4 = &newinet->cork.fl.u.ip4; 859 860 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark, 861 ip_sock_rt_tos(sk), ip_sock_rt_scope(sk), 862 sk->sk_protocol, inet_sk_flowi_flags(sk), 863 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, 864 ireq->ir_loc_addr, ireq->ir_rmt_port, 865 htons(ireq->ir_num), sk->sk_uid); 866 security_req_classify_flow(req, flowi4_to_flowi_common(fl4)); 867 rt = ip_route_output_flow(net, fl4, sk); 868 if (IS_ERR(rt)) 869 goto no_route; 870 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 871 goto route_err; 872 return &rt->dst; 873 874route_err: 875 ip_rt_put(rt); 876no_route: 877 __IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); 878 return NULL; 879} 880EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); 881 882/* Decide when to expire the request and when to resend SYN-ACK */ 883static void syn_ack_recalc(struct request_sock *req, 884 const int max_syn_ack_retries, 885 const u8 rskq_defer_accept, 886 int *expire, int *resend) 887{ 888 if (!rskq_defer_accept) { 889 *expire = req->num_timeout >= max_syn_ack_retries; 890 *resend = 1; 891 return; 892 } 893 *expire = req->num_timeout >= max_syn_ack_retries && 894 (!inet_rsk(req)->acked || req->num_timeout >= rskq_defer_accept); 895 /* Do not resend while waiting for data after ACK, 896 * start to resend on end of deferring period to give 897 * last chance for data or ACK to create established socket. 898 */ 899 *resend = !inet_rsk(req)->acked || 900 req->num_timeout >= rskq_defer_accept - 1; 901} 902 903int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req) 904{ 905 int err = req->rsk_ops->rtx_syn_ack(parent, req); 906 907 if (!err) 908 req->num_retrans++; 909 return err; 910} 911EXPORT_SYMBOL(inet_rtx_syn_ack); 912 913static struct request_sock *inet_reqsk_clone(struct request_sock *req, 914 struct sock *sk) 915{ 916 struct sock *req_sk, *nreq_sk; 917 struct request_sock *nreq; 918 919 nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN); 920 if (!nreq) { 921 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE); 922 923 /* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */ 924 sock_put(sk); 925 return NULL; 926 } 927 928 req_sk = req_to_sk(req); 929 nreq_sk = req_to_sk(nreq); 930 931 memcpy(nreq_sk, req_sk, 932 offsetof(struct sock, sk_dontcopy_begin)); 933 unsafe_memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end, 934 req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end), 935 /* alloc is larger than struct, see above */); 936 937 sk_node_init(&nreq_sk->sk_node); 938 nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping; 939#ifdef CONFIG_SOCK_RX_QUEUE_MAPPING 940 nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping; 941#endif 942 nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu; 943 944 nreq->rsk_listener = sk; 945 946 /* We need not acquire fastopenq->lock 947 * because the child socket is locked in inet_csk_listen_stop(). 948 */ 949 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener) 950 rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq); 951 952 return nreq; 953} 954 955static void reqsk_queue_migrated(struct request_sock_queue *queue, 956 const struct request_sock *req) 957{ 958 if (req->num_timeout == 0) 959 atomic_inc(&queue->young); 960 atomic_inc(&queue->qlen); 961} 962 963static void reqsk_migrate_reset(struct request_sock *req) 964{ 965 req->saved_syn = NULL; 966#if IS_ENABLED(CONFIG_IPV6) 967 inet_rsk(req)->ipv6_opt = NULL; 968 inet_rsk(req)->pktopts = NULL; 969#else 970 inet_rsk(req)->ireq_opt = NULL; 971#endif 972} 973 974/* return true if req was found in the ehash table */ 975static bool reqsk_queue_unlink(struct request_sock *req) 976{ 977 struct sock *sk = req_to_sk(req); 978 bool found = false; 979 980 if (sk_hashed(sk)) { 981 struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk); 982 spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash); 983 984 spin_lock(lock); 985 found = __sk_nulls_del_node_init_rcu(sk); 986 spin_unlock(lock); 987 } 988 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer)) 989 reqsk_put(req); 990 return found; 991} 992 993bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req) 994{ 995 bool unlinked = reqsk_queue_unlink(req); 996 997 if (unlinked) { 998 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req); 999 reqsk_put(req); 1000 } 1001 return unlinked; 1002} 1003EXPORT_SYMBOL(inet_csk_reqsk_queue_drop); 1004 1005void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req) 1006{ 1007 inet_csk_reqsk_queue_drop(sk, req); 1008 reqsk_put(req); 1009} 1010EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put); 1011 1012static void reqsk_timer_handler(struct timer_list *t) 1013{ 1014 struct request_sock *req = from_timer(req, t, rsk_timer); 1015 struct request_sock *nreq = NULL, *oreq = req; 1016 struct sock *sk_listener = req->rsk_listener; 1017 struct inet_connection_sock *icsk; 1018 struct request_sock_queue *queue; 1019 struct net *net; 1020 int max_syn_ack_retries, qlen, expire = 0, resend = 0; 1021 1022 if (inet_sk_state_load(sk_listener) != TCP_LISTEN) { 1023 struct sock *nsk; 1024 1025 nsk = reuseport_migrate_sock(sk_listener, req_to_sk(req), NULL); 1026 if (!nsk) 1027 goto drop; 1028 1029 nreq = inet_reqsk_clone(req, nsk); 1030 if (!nreq) 1031 goto drop; 1032 1033 /* The new timer for the cloned req can decrease the 2 1034 * by calling inet_csk_reqsk_queue_drop_and_put(), so 1035 * hold another count to prevent use-after-free and 1036 * call reqsk_put() just before return. 1037 */ 1038 refcount_set(&nreq->rsk_refcnt, 2 + 1); 1039 timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED); 1040 reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req); 1041 1042 req = nreq; 1043 sk_listener = nsk; 1044 } 1045 1046 icsk = inet_csk(sk_listener); 1047 net = sock_net(sk_listener); 1048 max_syn_ack_retries = READ_ONCE(icsk->icsk_syn_retries) ? : 1049 READ_ONCE(net->ipv4.sysctl_tcp_synack_retries); 1050 /* Normally all the openreqs are young and become mature 1051 * (i.e. converted to established socket) for first timeout. 1052 * If synack was not acknowledged for 1 second, it means 1053 * one of the following things: synack was lost, ack was lost, 1054 * rtt is high or nobody planned to ack (i.e. synflood). 1055 * When server is a bit loaded, queue is populated with old 1056 * open requests, reducing effective size of queue. 1057 * When server is well loaded, queue size reduces to zero 1058 * after several minutes of work. It is not synflood, 1059 * it is normal operation. The solution is pruning 1060 * too old entries overriding normal timeout, when 1061 * situation becomes dangerous. 1062 * 1063 * Essentially, we reserve half of room for young 1064 * embrions; and abort old ones without pity, if old 1065 * ones are about to clog our table. 1066 */ 1067 queue = &icsk->icsk_accept_queue; 1068 qlen = reqsk_queue_len(queue); 1069 if ((qlen << 1) > max(8U, READ_ONCE(sk_listener->sk_max_ack_backlog))) { 1070 int young = reqsk_queue_len_young(queue) << 1; 1071 1072 while (max_syn_ack_retries > 2) { 1073 if (qlen < young) 1074 break; 1075 max_syn_ack_retries--; 1076 young <<= 1; 1077 } 1078 } 1079 syn_ack_recalc(req, max_syn_ack_retries, READ_ONCE(queue->rskq_defer_accept), 1080 &expire, &resend); 1081 req->rsk_ops->syn_ack_timeout(req); 1082 if (!expire && 1083 (!resend || 1084 !inet_rtx_syn_ack(sk_listener, req) || 1085 inet_rsk(req)->acked)) { 1086 if (req->num_timeout++ == 0) 1087 atomic_dec(&queue->young); 1088 mod_timer(&req->rsk_timer, jiffies + reqsk_timeout(req, TCP_RTO_MAX)); 1089 1090 if (!nreq) 1091 return; 1092 1093 if (!inet_ehash_insert(req_to_sk(nreq), req_to_sk(oreq), NULL)) { 1094 /* delete timer */ 1095 inet_csk_reqsk_queue_drop(sk_listener, nreq); 1096 goto no_ownership; 1097 } 1098 1099 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQSUCCESS); 1100 reqsk_migrate_reset(oreq); 1101 reqsk_queue_removed(&inet_csk(oreq->rsk_listener)->icsk_accept_queue, oreq); 1102 reqsk_put(oreq); 1103 1104 reqsk_put(nreq); 1105 return; 1106 } 1107 1108 /* Even if we can clone the req, we may need not retransmit any more 1109 * SYN+ACKs (nreq->num_timeout > max_syn_ack_retries, etc), or another 1110 * CPU may win the "own_req" race so that inet_ehash_insert() fails. 1111 */ 1112 if (nreq) { 1113 __NET_INC_STATS(net, LINUX_MIB_TCPMIGRATEREQFAILURE); 1114no_ownership: 1115 reqsk_migrate_reset(nreq); 1116 reqsk_queue_removed(queue, nreq); 1117 __reqsk_free(nreq); 1118 } 1119 1120drop: 1121 inet_csk_reqsk_queue_drop_and_put(oreq->rsk_listener, oreq); 1122} 1123 1124static void reqsk_queue_hash_req(struct request_sock *req, 1125 unsigned long timeout) 1126{ 1127 timer_setup(&req->rsk_timer, reqsk_timer_handler, TIMER_PINNED); 1128 mod_timer(&req->rsk_timer, jiffies + timeout); 1129 1130 inet_ehash_insert(req_to_sk(req), NULL, NULL); 1131 /* before letting lookups find us, make sure all req fields 1132 * are committed to memory and refcnt initialized. 1133 */ 1134 smp_wmb(); 1135 refcount_set(&req->rsk_refcnt, 2 + 1); 1136} 1137 1138void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, 1139 unsigned long timeout) 1140{ 1141 reqsk_queue_hash_req(req, timeout); 1142 inet_csk_reqsk_queue_added(sk); 1143} 1144EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); 1145 1146static void inet_clone_ulp(const struct request_sock *req, struct sock *newsk, 1147 const gfp_t priority) 1148{ 1149 struct inet_connection_sock *icsk = inet_csk(newsk); 1150 1151 if (!icsk->icsk_ulp_ops) 1152 return; 1153 1154 icsk->icsk_ulp_ops->clone(req, newsk, priority); 1155} 1156 1157/** 1158 * inet_csk_clone_lock - clone an inet socket, and lock its clone 1159 * @sk: the socket to clone 1160 * @req: request_sock 1161 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc) 1162 * 1163 * Caller must unlock socket even in error path (bh_unlock_sock(newsk)) 1164 */ 1165struct sock *inet_csk_clone_lock(const struct sock *sk, 1166 const struct request_sock *req, 1167 const gfp_t priority) 1168{ 1169 struct sock *newsk = sk_clone_lock(sk, priority); 1170 1171 if (newsk) { 1172 struct inet_connection_sock *newicsk = inet_csk(newsk); 1173 1174 inet_sk_set_state(newsk, TCP_SYN_RECV); 1175 newicsk->icsk_bind_hash = NULL; 1176 newicsk->icsk_bind2_hash = NULL; 1177 1178 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port; 1179 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num; 1180 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num); 1181 1182 /* listeners have SOCK_RCU_FREE, not the children */ 1183 sock_reset_flag(newsk, SOCK_RCU_FREE); 1184 1185 inet_sk(newsk)->mc_list = NULL; 1186 1187 newsk->sk_mark = inet_rsk(req)->ir_mark; 1188 atomic64_set(&newsk->sk_cookie, 1189 atomic64_read(&inet_rsk(req)->ir_cookie)); 1190 1191 newicsk->icsk_retransmits = 0; 1192 newicsk->icsk_backoff = 0; 1193 newicsk->icsk_probes_out = 0; 1194 newicsk->icsk_probes_tstamp = 0; 1195 1196 /* Deinitialize accept_queue to trap illegal accesses. */ 1197 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue)); 1198 1199 inet_clone_ulp(req, newsk, priority); 1200 1201 security_inet_csk_clone(newsk, req); 1202 } 1203 return newsk; 1204} 1205EXPORT_SYMBOL_GPL(inet_csk_clone_lock); 1206 1207/* 1208 * At this point, there should be no process reference to this 1209 * socket, and thus no user references at all. Therefore we 1210 * can assume the socket waitqueue is inactive and nobody will 1211 * try to jump onto it. 1212 */ 1213void inet_csk_destroy_sock(struct sock *sk) 1214{ 1215 WARN_ON(sk->sk_state != TCP_CLOSE); 1216 WARN_ON(!sock_flag(sk, SOCK_DEAD)); 1217 1218 /* It cannot be in hash table! */ 1219 WARN_ON(!sk_unhashed(sk)); 1220 1221 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */ 1222 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash); 1223 1224 sk->sk_prot->destroy(sk); 1225 1226 sk_stream_kill_queues(sk); 1227 1228 xfrm_sk_free_policy(sk); 1229 1230 this_cpu_dec(*sk->sk_prot->orphan_count); 1231 1232 sock_put(sk); 1233} 1234EXPORT_SYMBOL(inet_csk_destroy_sock); 1235 1236/* This function allows to force a closure of a socket after the call to 1237 * tcp/dccp_create_openreq_child(). 1238 */ 1239void inet_csk_prepare_forced_close(struct sock *sk) 1240 __releases(&sk->sk_lock.slock) 1241{ 1242 /* sk_clone_lock locked the socket and set refcnt to 2 */ 1243 bh_unlock_sock(sk); 1244 sock_put(sk); 1245 inet_csk_prepare_for_destroy_sock(sk); 1246 inet_sk(sk)->inet_num = 0; 1247} 1248EXPORT_SYMBOL(inet_csk_prepare_forced_close); 1249 1250static int inet_ulp_can_listen(const struct sock *sk) 1251{ 1252 const struct inet_connection_sock *icsk = inet_csk(sk); 1253 1254 if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone) 1255 return -EINVAL; 1256 1257 return 0; 1258} 1259 1260int inet_csk_listen_start(struct sock *sk) 1261{ 1262 struct inet_connection_sock *icsk = inet_csk(sk); 1263 struct inet_sock *inet = inet_sk(sk); 1264 int err; 1265 1266 err = inet_ulp_can_listen(sk); 1267 if (unlikely(err)) 1268 return err; 1269 1270 reqsk_queue_alloc(&icsk->icsk_accept_queue); 1271 1272 sk->sk_ack_backlog = 0; 1273 inet_csk_delack_init(sk); 1274 1275 /* There is race window here: we announce ourselves listening, 1276 * but this transition is still not validated by get_port(). 1277 * It is OK, because this socket enters to hash table only 1278 * after validation is complete. 1279 */ 1280 inet_sk_state_store(sk, TCP_LISTEN); 1281 err = sk->sk_prot->get_port(sk, inet->inet_num); 1282 if (!err) { 1283 inet->inet_sport = htons(inet->inet_num); 1284 1285 sk_dst_reset(sk); 1286 err = sk->sk_prot->hash(sk); 1287 1288 if (likely(!err)) 1289 return 0; 1290 } 1291 1292 inet_sk_set_state(sk, TCP_CLOSE); 1293 return err; 1294} 1295EXPORT_SYMBOL_GPL(inet_csk_listen_start); 1296 1297static void inet_child_forget(struct sock *sk, struct request_sock *req, 1298 struct sock *child) 1299{ 1300 sk->sk_prot->disconnect(child, O_NONBLOCK); 1301 1302 sock_orphan(child); 1303 1304 this_cpu_inc(*sk->sk_prot->orphan_count); 1305 1306 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) { 1307 BUG_ON(rcu_access_pointer(tcp_sk(child)->fastopen_rsk) != req); 1308 BUG_ON(sk != req->rsk_listener); 1309 1310 /* Paranoid, to prevent race condition if 1311 * an inbound pkt destined for child is 1312 * blocked by sock lock in tcp_v4_rcv(). 1313 * Also to satisfy an assertion in 1314 * tcp_v4_destroy_sock(). 1315 */ 1316 RCU_INIT_POINTER(tcp_sk(child)->fastopen_rsk, NULL); 1317 } 1318 inet_csk_destroy_sock(child); 1319} 1320 1321struct sock *inet_csk_reqsk_queue_add(struct sock *sk, 1322 struct request_sock *req, 1323 struct sock *child) 1324{ 1325 struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; 1326 1327 spin_lock(&queue->rskq_lock); 1328 if (unlikely(sk->sk_state != TCP_LISTEN)) { 1329 inet_child_forget(sk, req, child); 1330 child = NULL; 1331 } else { 1332 req->sk = child; 1333 req->dl_next = NULL; 1334 if (queue->rskq_accept_head == NULL) 1335 WRITE_ONCE(queue->rskq_accept_head, req); 1336 else 1337 queue->rskq_accept_tail->dl_next = req; 1338 queue->rskq_accept_tail = req; 1339 sk_acceptq_added(sk); 1340 } 1341 spin_unlock(&queue->rskq_lock); 1342 return child; 1343} 1344EXPORT_SYMBOL(inet_csk_reqsk_queue_add); 1345 1346struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child, 1347 struct request_sock *req, bool own_req) 1348{ 1349 if (own_req) { 1350 inet_csk_reqsk_queue_drop(req->rsk_listener, req); 1351 reqsk_queue_removed(&inet_csk(req->rsk_listener)->icsk_accept_queue, req); 1352 1353 if (sk != req->rsk_listener) { 1354 /* another listening sk has been selected, 1355 * migrate the req to it. 1356 */ 1357 struct request_sock *nreq; 1358 1359 /* hold a refcnt for the nreq->rsk_listener 1360 * which is assigned in inet_reqsk_clone() 1361 */ 1362 sock_hold(sk); 1363 nreq = inet_reqsk_clone(req, sk); 1364 if (!nreq) { 1365 inet_child_forget(sk, req, child); 1366 goto child_put; 1367 } 1368 1369 refcount_set(&nreq->rsk_refcnt, 1); 1370 if (inet_csk_reqsk_queue_add(sk, nreq, child)) { 1371 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS); 1372 reqsk_migrate_reset(req); 1373 reqsk_put(req); 1374 return child; 1375 } 1376 1377 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQFAILURE); 1378 reqsk_migrate_reset(nreq); 1379 __reqsk_free(nreq); 1380 } else if (inet_csk_reqsk_queue_add(sk, req, child)) { 1381 return child; 1382 } 1383 } 1384 /* Too bad, another child took ownership of the request, undo. */ 1385child_put: 1386 bh_unlock_sock(child); 1387 sock_put(child); 1388 return NULL; 1389} 1390EXPORT_SYMBOL(inet_csk_complete_hashdance); 1391 1392/* 1393 * This routine closes sockets which have been at least partially 1394 * opened, but not yet accepted. 1395 */ 1396void inet_csk_listen_stop(struct sock *sk) 1397{ 1398 struct inet_connection_sock *icsk = inet_csk(sk); 1399 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 1400 struct request_sock *next, *req; 1401 1402 /* Following specs, it would be better either to send FIN 1403 * (and enter FIN-WAIT-1, it is normal close) 1404 * or to send active reset (abort). 1405 * Certainly, it is pretty dangerous while synflood, but it is 1406 * bad justification for our negligence 8) 1407 * To be honest, we are not able to make either 1408 * of the variants now. --ANK 1409 */ 1410 while ((req = reqsk_queue_remove(queue, sk)) != NULL) { 1411 struct sock *child = req->sk, *nsk; 1412 struct request_sock *nreq; 1413 1414 local_bh_disable(); 1415 bh_lock_sock(child); 1416 WARN_ON(sock_owned_by_user(child)); 1417 sock_hold(child); 1418 1419 nsk = reuseport_migrate_sock(sk, child, NULL); 1420 if (nsk) { 1421 nreq = inet_reqsk_clone(req, nsk); 1422 if (nreq) { 1423 refcount_set(&nreq->rsk_refcnt, 1); 1424 1425 if (inet_csk_reqsk_queue_add(nsk, nreq, child)) { 1426 __NET_INC_STATS(sock_net(nsk), 1427 LINUX_MIB_TCPMIGRATEREQSUCCESS); 1428 reqsk_migrate_reset(req); 1429 } else { 1430 __NET_INC_STATS(sock_net(nsk), 1431 LINUX_MIB_TCPMIGRATEREQFAILURE); 1432 reqsk_migrate_reset(nreq); 1433 __reqsk_free(nreq); 1434 } 1435 1436 /* inet_csk_reqsk_queue_add() has already 1437 * called inet_child_forget() on failure case. 1438 */ 1439 goto skip_child_forget; 1440 } 1441 } 1442 1443 inet_child_forget(sk, req, child); 1444skip_child_forget: 1445 reqsk_put(req); 1446 bh_unlock_sock(child); 1447 local_bh_enable(); 1448 sock_put(child); 1449 1450 cond_resched(); 1451 } 1452 if (queue->fastopenq.rskq_rst_head) { 1453 /* Free all the reqs queued in rskq_rst_head. */ 1454 spin_lock_bh(&queue->fastopenq.lock); 1455 req = queue->fastopenq.rskq_rst_head; 1456 queue->fastopenq.rskq_rst_head = NULL; 1457 spin_unlock_bh(&queue->fastopenq.lock); 1458 while (req != NULL) { 1459 next = req->dl_next; 1460 reqsk_put(req); 1461 req = next; 1462 } 1463 } 1464 WARN_ON_ONCE(sk->sk_ack_backlog); 1465} 1466EXPORT_SYMBOL_GPL(inet_csk_listen_stop); 1467 1468void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr) 1469{ 1470 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr; 1471 const struct inet_sock *inet = inet_sk(sk); 1472 1473 sin->sin_family = AF_INET; 1474 sin->sin_addr.s_addr = inet->inet_daddr; 1475 sin->sin_port = inet->inet_dport; 1476} 1477EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr); 1478 1479static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl) 1480{ 1481 const struct inet_sock *inet = inet_sk(sk); 1482 const struct ip_options_rcu *inet_opt; 1483 __be32 daddr = inet->inet_daddr; 1484 struct flowi4 *fl4; 1485 struct rtable *rt; 1486 1487 rcu_read_lock(); 1488 inet_opt = rcu_dereference(inet->inet_opt); 1489 if (inet_opt && inet_opt->opt.srr) 1490 daddr = inet_opt->opt.faddr; 1491 fl4 = &fl->u.ip4; 1492 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, 1493 inet->inet_saddr, inet->inet_dport, 1494 inet->inet_sport, sk->sk_protocol, 1495 ip_sock_rt_tos(sk), sk->sk_bound_dev_if); 1496 if (IS_ERR(rt)) 1497 rt = NULL; 1498 if (rt) 1499 sk_setup_caps(sk, &rt->dst); 1500 rcu_read_unlock(); 1501 1502 return &rt->dst; 1503} 1504 1505struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu) 1506{ 1507 struct dst_entry *dst = __sk_dst_check(sk, 0); 1508 struct inet_sock *inet = inet_sk(sk); 1509 1510 if (!dst) { 1511 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 1512 if (!dst) 1513 goto out; 1514 } 1515 dst->ops->update_pmtu(dst, sk, NULL, mtu, true); 1516 1517 dst = __sk_dst_check(sk, 0); 1518 if (!dst) 1519 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 1520out: 1521 return dst; 1522} 1523EXPORT_SYMBOL_GPL(inet_csk_update_pmtu); 1524