1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Support for INET connection oriented protocols. 7 * 8 * Authors: See the TCP sources 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or(at your option) any later version. 14 */ 15 16 #include <linux/module.h> 17 #include <linux/jhash.h> 18 19 #include <net/inet_connection_sock.h> 20 #include <net/inet_hashtables.h> 21 #include <net/inet_timewait_sock.h> 22 #include <net/ip.h> 23 #include <net/route.h> 24 #include <net/tcp_states.h> 25 #include <net/xfrm.h> 26 27 #ifdef INET_CSK_DEBUG 28 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n"; 29 EXPORT_SYMBOL(inet_csk_timer_bug_msg); 30 #endif 31 32 /* 33 * This struct holds the first and last local port number. 34 */ 35 struct local_ports sysctl_local_ports __read_mostly = { 36 .lock = __SEQLOCK_UNLOCKED(sysctl_local_ports.lock), 37 .range = { 32768, 61000 }, 38 }; 39 40 unsigned long *sysctl_local_reserved_ports; 41 EXPORT_SYMBOL(sysctl_local_reserved_ports); 42 43 void inet_get_local_port_range(int *low, int *high) 44 { 45 unsigned int seq; 46 47 do { 48 seq = read_seqbegin(&sysctl_local_ports.lock); 49 50 *low = sysctl_local_ports.range[0]; 51 *high = sysctl_local_ports.range[1]; 52 } while (read_seqretry(&sysctl_local_ports.lock, seq)); 53 } 54 EXPORT_SYMBOL(inet_get_local_port_range); 55 56 int inet_csk_bind_conflict(const struct sock *sk, 57 const struct inet_bind_bucket *tb, bool relax) 58 { 59 struct sock *sk2; 60 int reuse = sk->sk_reuse; 61 int reuseport = sk->sk_reuseport; 62 kuid_t uid = sock_i_uid((struct sock *)sk); 63 64 /* 65 * Unlike other sk lookup places we do not check 66 * for sk_net here, since _all_ the socks listed 67 * in tb->owners list belong to the same net - the 68 * one this bucket belongs to. 69 */ 70 71 sk_for_each_bound(sk2, &tb->owners) { 72 if (sk != sk2 && 73 !inet_v6_ipv6only(sk2) && 74 (!sk->sk_bound_dev_if || 75 !sk2->sk_bound_dev_if || 76 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) { 77 if ((!reuse || !sk2->sk_reuse || 78 sk2->sk_state == TCP_LISTEN) && 79 (!reuseport || !sk2->sk_reuseport || 80 (sk2->sk_state != TCP_TIME_WAIT && 81 !uid_eq(uid, sock_i_uid(sk2))))) { 82 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2); 83 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) || 84 sk2_rcv_saddr == sk_rcv_saddr(sk)) 85 break; 86 } 87 if (!relax && reuse && sk2->sk_reuse && 88 sk2->sk_state != TCP_LISTEN) { 89 const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2); 90 91 if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) || 92 sk2_rcv_saddr == sk_rcv_saddr(sk)) 93 break; 94 } 95 } 96 } 97 return sk2 != NULL; 98 } 99 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict); 100 101 /* Obtain a reference to a local port for the given sock, 102 * if snum is zero it means select any available local port. 103 */ 104 int inet_csk_get_port(struct sock *sk, unsigned short snum) 105 { 106 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 107 struct inet_bind_hashbucket *head; 108 struct inet_bind_bucket *tb; 109 int ret, attempts = 5; 110 struct net *net = sock_net(sk); 111 int smallest_size = -1, smallest_rover; 112 kuid_t uid = sock_i_uid(sk); 113 114 local_bh_disable(); 115 if (!snum) { 116 int remaining, rover, low, high; 117 118 again: 119 inet_get_local_port_range(&low, &high); 120 remaining = (high - low) + 1; 121 smallest_rover = rover = net_random() % remaining + low; 122 123 smallest_size = -1; 124 do { 125 if (inet_is_reserved_local_port(rover)) 126 goto next_nolock; 127 head = &hashinfo->bhash[inet_bhashfn(net, rover, 128 hashinfo->bhash_size)]; 129 spin_lock(&head->lock); 130 inet_bind_bucket_for_each(tb, &head->chain) 131 if (net_eq(ib_net(tb), net) && tb->port == rover) { 132 if (((tb->fastreuse > 0 && 133 sk->sk_reuse && 134 sk->sk_state != TCP_LISTEN) || 135 (tb->fastreuseport > 0 && 136 sk->sk_reuseport && 137 uid_eq(tb->fastuid, uid))) && 138 (tb->num_owners < smallest_size || smallest_size == -1)) { 139 smallest_size = tb->num_owners; 140 smallest_rover = rover; 141 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 && 142 !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) { 143 snum = smallest_rover; 144 goto tb_found; 145 } 146 } 147 if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) { 148 snum = rover; 149 goto tb_found; 150 } 151 goto next; 152 } 153 break; 154 next: 155 spin_unlock(&head->lock); 156 next_nolock: 157 if (++rover > high) 158 rover = low; 159 } while (--remaining > 0); 160 161 /* Exhausted local port range during search? It is not 162 * possible for us to be holding one of the bind hash 163 * locks if this test triggers, because if 'remaining' 164 * drops to zero, we broke out of the do/while loop at 165 * the top level, not from the 'break;' statement. 166 */ 167 ret = 1; 168 if (remaining <= 0) { 169 if (smallest_size != -1) { 170 snum = smallest_rover; 171 goto have_snum; 172 } 173 goto fail; 174 } 175 /* OK, here is the one we will use. HEAD is 176 * non-NULL and we hold it's mutex. 177 */ 178 snum = rover; 179 } else { 180 have_snum: 181 head = &hashinfo->bhash[inet_bhashfn(net, snum, 182 hashinfo->bhash_size)]; 183 spin_lock(&head->lock); 184 inet_bind_bucket_for_each(tb, &head->chain) 185 if (net_eq(ib_net(tb), net) && tb->port == snum) 186 goto tb_found; 187 } 188 tb = NULL; 189 goto tb_not_found; 190 tb_found: 191 if (!hlist_empty(&tb->owners)) { 192 if (sk->sk_reuse == SK_FORCE_REUSE) 193 goto success; 194 195 if (((tb->fastreuse > 0 && 196 sk->sk_reuse && sk->sk_state != TCP_LISTEN) || 197 (tb->fastreuseport > 0 && 198 sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && 199 smallest_size == -1) { 200 goto success; 201 } else { 202 ret = 1; 203 if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) { 204 if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) || 205 (tb->fastreuseport > 0 && 206 sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && 207 smallest_size != -1 && --attempts >= 0) { 208 spin_unlock(&head->lock); 209 goto again; 210 } 211 212 goto fail_unlock; 213 } 214 } 215 } 216 tb_not_found: 217 ret = 1; 218 if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep, 219 net, head, snum)) == NULL) 220 goto fail_unlock; 221 if (hlist_empty(&tb->owners)) { 222 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN) 223 tb->fastreuse = 1; 224 else 225 tb->fastreuse = 0; 226 if (sk->sk_reuseport) { 227 tb->fastreuseport = 1; 228 tb->fastuid = uid; 229 } else 230 tb->fastreuseport = 0; 231 } else { 232 if (tb->fastreuse && 233 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN)) 234 tb->fastreuse = 0; 235 if (tb->fastreuseport && 236 (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))) 237 tb->fastreuseport = 0; 238 } 239 success: 240 if (!inet_csk(sk)->icsk_bind_hash) 241 inet_bind_hash(sk, tb, snum); 242 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); 243 ret = 0; 244 245 fail_unlock: 246 spin_unlock(&head->lock); 247 fail: 248 local_bh_enable(); 249 return ret; 250 } 251 EXPORT_SYMBOL_GPL(inet_csk_get_port); 252 253 /* 254 * Wait for an incoming connection, avoid race conditions. This must be called 255 * with the socket locked. 256 */ 257 static int inet_csk_wait_for_connect(struct sock *sk, long timeo) 258 { 259 struct inet_connection_sock *icsk = inet_csk(sk); 260 DEFINE_WAIT(wait); 261 int err; 262 263 /* 264 * True wake-one mechanism for incoming connections: only 265 * one process gets woken up, not the 'whole herd'. 266 * Since we do not 'race & poll' for established sockets 267 * anymore, the common case will execute the loop only once. 268 * 269 * Subtle issue: "add_wait_queue_exclusive()" will be added 270 * after any current non-exclusive waiters, and we know that 271 * it will always _stay_ after any new non-exclusive waiters 272 * because all non-exclusive waiters are added at the 273 * beginning of the wait-queue. As such, it's ok to "drop" 274 * our exclusiveness temporarily when we get woken up without 275 * having to remove and re-insert us on the wait queue. 276 */ 277 for (;;) { 278 prepare_to_wait_exclusive(sk_sleep(sk), &wait, 279 TASK_INTERRUPTIBLE); 280 release_sock(sk); 281 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) 282 timeo = schedule_timeout(timeo); 283 lock_sock(sk); 284 err = 0; 285 if (!reqsk_queue_empty(&icsk->icsk_accept_queue)) 286 break; 287 err = -EINVAL; 288 if (sk->sk_state != TCP_LISTEN) 289 break; 290 err = sock_intr_errno(timeo); 291 if (signal_pending(current)) 292 break; 293 err = -EAGAIN; 294 if (!timeo) 295 break; 296 } 297 finish_wait(sk_sleep(sk), &wait); 298 return err; 299 } 300 301 /* 302 * This will accept the next outstanding connection. 303 */ 304 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err) 305 { 306 struct inet_connection_sock *icsk = inet_csk(sk); 307 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 308 struct sock *newsk; 309 struct request_sock *req; 310 int error; 311 312 lock_sock(sk); 313 314 /* We need to make sure that this socket is listening, 315 * and that it has something pending. 316 */ 317 error = -EINVAL; 318 if (sk->sk_state != TCP_LISTEN) 319 goto out_err; 320 321 /* Find already established connection */ 322 if (reqsk_queue_empty(queue)) { 323 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK); 324 325 /* If this is a non blocking socket don't sleep */ 326 error = -EAGAIN; 327 if (!timeo) 328 goto out_err; 329 330 error = inet_csk_wait_for_connect(sk, timeo); 331 if (error) 332 goto out_err; 333 } 334 req = reqsk_queue_remove(queue); 335 newsk = req->sk; 336 337 sk_acceptq_removed(sk); 338 if (sk->sk_protocol == IPPROTO_TCP && queue->fastopenq != NULL) { 339 spin_lock_bh(&queue->fastopenq->lock); 340 if (tcp_rsk(req)->listener) { 341 /* We are still waiting for the final ACK from 3WHS 342 * so can't free req now. Instead, we set req->sk to 343 * NULL to signify that the child socket is taken 344 * so reqsk_fastopen_remove() will free the req 345 * when 3WHS finishes (or is aborted). 346 */ 347 req->sk = NULL; 348 req = NULL; 349 } 350 spin_unlock_bh(&queue->fastopenq->lock); 351 } 352 out: 353 release_sock(sk); 354 if (req) 355 __reqsk_free(req); 356 return newsk; 357 out_err: 358 newsk = NULL; 359 req = NULL; 360 *err = error; 361 goto out; 362 } 363 EXPORT_SYMBOL(inet_csk_accept); 364 365 /* 366 * Using different timers for retransmit, delayed acks and probes 367 * We may wish use just one timer maintaining a list of expire jiffies 368 * to optimize. 369 */ 370 void inet_csk_init_xmit_timers(struct sock *sk, 371 void (*retransmit_handler)(unsigned long), 372 void (*delack_handler)(unsigned long), 373 void (*keepalive_handler)(unsigned long)) 374 { 375 struct inet_connection_sock *icsk = inet_csk(sk); 376 377 setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler, 378 (unsigned long)sk); 379 setup_timer(&icsk->icsk_delack_timer, delack_handler, 380 (unsigned long)sk); 381 setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk); 382 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 383 } 384 EXPORT_SYMBOL(inet_csk_init_xmit_timers); 385 386 void inet_csk_clear_xmit_timers(struct sock *sk) 387 { 388 struct inet_connection_sock *icsk = inet_csk(sk); 389 390 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0; 391 392 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 393 sk_stop_timer(sk, &icsk->icsk_delack_timer); 394 sk_stop_timer(sk, &sk->sk_timer); 395 } 396 EXPORT_SYMBOL(inet_csk_clear_xmit_timers); 397 398 void inet_csk_delete_keepalive_timer(struct sock *sk) 399 { 400 sk_stop_timer(sk, &sk->sk_timer); 401 } 402 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer); 403 404 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) 405 { 406 sk_reset_timer(sk, &sk->sk_timer, jiffies + len); 407 } 408 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer); 409 410 struct dst_entry *inet_csk_route_req(struct sock *sk, 411 struct flowi4 *fl4, 412 const struct request_sock *req) 413 { 414 struct rtable *rt; 415 const struct inet_request_sock *ireq = inet_rsk(req); 416 struct ip_options_rcu *opt = inet_rsk(req)->opt; 417 struct net *net = sock_net(sk); 418 int flags = inet_sk_flowi_flags(sk); 419 420 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 421 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 422 sk->sk_protocol, 423 flags, 424 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr, 425 ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport); 426 security_req_classify_flow(req, flowi4_to_flowi(fl4)); 427 rt = ip_route_output_flow(net, fl4, sk); 428 if (IS_ERR(rt)) 429 goto no_route; 430 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 431 goto route_err; 432 return &rt->dst; 433 434 route_err: 435 ip_rt_put(rt); 436 no_route: 437 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES); 438 return NULL; 439 } 440 EXPORT_SYMBOL_GPL(inet_csk_route_req); 441 442 struct dst_entry *inet_csk_route_child_sock(struct sock *sk, 443 struct sock *newsk, 444 const struct request_sock *req) 445 { 446 const struct inet_request_sock *ireq = inet_rsk(req); 447 struct inet_sock *newinet = inet_sk(newsk); 448 struct ip_options_rcu *opt; 449 struct net *net = sock_net(sk); 450 struct flowi4 *fl4; 451 struct rtable *rt; 452 453 fl4 = &newinet->cork.fl.u.ip4; 454 455 rcu_read_lock(); 456 opt = rcu_dereference(newinet->inet_opt); 457 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 458 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 459 sk->sk_protocol, inet_sk_flowi_flags(sk), 460 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr, 461 ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport); 462 security_req_classify_flow(req, flowi4_to_flowi(fl4)); 463 rt = ip_route_output_flow(net, fl4, sk); 464 if (IS_ERR(rt)) 465 goto no_route; 466 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 467 goto route_err; 468 rcu_read_unlock(); 469 return &rt->dst; 470 471 route_err: 472 ip_rt_put(rt); 473 no_route: 474 rcu_read_unlock(); 475 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES); 476 return NULL; 477 } 478 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); 479 480 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport, 481 const u32 rnd, const u32 synq_hsize) 482 { 483 return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1); 484 } 485 486 #if IS_ENABLED(CONFIG_IPV6) 487 #define AF_INET_FAMILY(fam) ((fam) == AF_INET) 488 #else 489 #define AF_INET_FAMILY(fam) 1 490 #endif 491 492 struct request_sock *inet_csk_search_req(const struct sock *sk, 493 struct request_sock ***prevp, 494 const __be16 rport, const __be32 raddr, 495 const __be32 laddr) 496 { 497 const struct inet_connection_sock *icsk = inet_csk(sk); 498 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; 499 struct request_sock *req, **prev; 500 501 for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd, 502 lopt->nr_table_entries)]; 503 (req = *prev) != NULL; 504 prev = &req->dl_next) { 505 const struct inet_request_sock *ireq = inet_rsk(req); 506 507 if (ireq->rmt_port == rport && 508 ireq->rmt_addr == raddr && 509 ireq->loc_addr == laddr && 510 AF_INET_FAMILY(req->rsk_ops->family)) { 511 WARN_ON(req->sk); 512 *prevp = prev; 513 break; 514 } 515 } 516 517 return req; 518 } 519 EXPORT_SYMBOL_GPL(inet_csk_search_req); 520 521 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, 522 unsigned long timeout) 523 { 524 struct inet_connection_sock *icsk = inet_csk(sk); 525 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; 526 const u32 h = inet_synq_hash(inet_rsk(req)->rmt_addr, inet_rsk(req)->rmt_port, 527 lopt->hash_rnd, lopt->nr_table_entries); 528 529 reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout); 530 inet_csk_reqsk_queue_added(sk, timeout); 531 } 532 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); 533 534 /* Only thing we need from tcp.h */ 535 extern int sysctl_tcp_synack_retries; 536 537 538 /* Decide when to expire the request and when to resend SYN-ACK */ 539 static inline void syn_ack_recalc(struct request_sock *req, const int thresh, 540 const int max_retries, 541 const u8 rskq_defer_accept, 542 int *expire, int *resend) 543 { 544 if (!rskq_defer_accept) { 545 *expire = req->num_timeout >= thresh; 546 *resend = 1; 547 return; 548 } 549 *expire = req->num_timeout >= thresh && 550 (!inet_rsk(req)->acked || req->num_timeout >= max_retries); 551 /* 552 * Do not resend while waiting for data after ACK, 553 * start to resend on end of deferring period to give 554 * last chance for data or ACK to create established socket. 555 */ 556 *resend = !inet_rsk(req)->acked || 557 req->num_timeout >= rskq_defer_accept - 1; 558 } 559 560 int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req) 561 { 562 int err = req->rsk_ops->rtx_syn_ack(parent, req); 563 564 if (!err) 565 req->num_retrans++; 566 return err; 567 } 568 EXPORT_SYMBOL(inet_rtx_syn_ack); 569 570 void inet_csk_reqsk_queue_prune(struct sock *parent, 571 const unsigned long interval, 572 const unsigned long timeout, 573 const unsigned long max_rto) 574 { 575 struct inet_connection_sock *icsk = inet_csk(parent); 576 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 577 struct listen_sock *lopt = queue->listen_opt; 578 int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries; 579 int thresh = max_retries; 580 unsigned long now = jiffies; 581 struct request_sock **reqp, *req; 582 int i, budget; 583 584 if (lopt == NULL || lopt->qlen == 0) 585 return; 586 587 /* Normally all the openreqs are young and become mature 588 * (i.e. converted to established socket) for first timeout. 589 * If synack was not acknowledged for 1 second, it means 590 * one of the following things: synack was lost, ack was lost, 591 * rtt is high or nobody planned to ack (i.e. synflood). 592 * When server is a bit loaded, queue is populated with old 593 * open requests, reducing effective size of queue. 594 * When server is well loaded, queue size reduces to zero 595 * after several minutes of work. It is not synflood, 596 * it is normal operation. The solution is pruning 597 * too old entries overriding normal timeout, when 598 * situation becomes dangerous. 599 * 600 * Essentially, we reserve half of room for young 601 * embrions; and abort old ones without pity, if old 602 * ones are about to clog our table. 603 */ 604 if (lopt->qlen>>(lopt->max_qlen_log-1)) { 605 int young = (lopt->qlen_young<<1); 606 607 while (thresh > 2) { 608 if (lopt->qlen < young) 609 break; 610 thresh--; 611 young <<= 1; 612 } 613 } 614 615 if (queue->rskq_defer_accept) 616 max_retries = queue->rskq_defer_accept; 617 618 budget = 2 * (lopt->nr_table_entries / (timeout / interval)); 619 i = lopt->clock_hand; 620 621 do { 622 reqp=&lopt->syn_table[i]; 623 while ((req = *reqp) != NULL) { 624 if (time_after_eq(now, req->expires)) { 625 int expire = 0, resend = 0; 626 627 syn_ack_recalc(req, thresh, max_retries, 628 queue->rskq_defer_accept, 629 &expire, &resend); 630 req->rsk_ops->syn_ack_timeout(parent, req); 631 if (!expire && 632 (!resend || 633 !inet_rtx_syn_ack(parent, req) || 634 inet_rsk(req)->acked)) { 635 unsigned long timeo; 636 637 if (req->num_timeout++ == 0) 638 lopt->qlen_young--; 639 timeo = min(timeout << req->num_timeout, 640 max_rto); 641 req->expires = now + timeo; 642 reqp = &req->dl_next; 643 continue; 644 } 645 646 /* Drop this request */ 647 inet_csk_reqsk_queue_unlink(parent, req, reqp); 648 reqsk_queue_removed(queue, req); 649 reqsk_free(req); 650 continue; 651 } 652 reqp = &req->dl_next; 653 } 654 655 i = (i + 1) & (lopt->nr_table_entries - 1); 656 657 } while (--budget > 0); 658 659 lopt->clock_hand = i; 660 661 if (lopt->qlen) 662 inet_csk_reset_keepalive_timer(parent, interval); 663 } 664 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune); 665 666 /** 667 * inet_csk_clone_lock - clone an inet socket, and lock its clone 668 * @sk: the socket to clone 669 * @req: request_sock 670 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc) 671 * 672 * Caller must unlock socket even in error path (bh_unlock_sock(newsk)) 673 */ 674 struct sock *inet_csk_clone_lock(const struct sock *sk, 675 const struct request_sock *req, 676 const gfp_t priority) 677 { 678 struct sock *newsk = sk_clone_lock(sk, priority); 679 680 if (newsk != NULL) { 681 struct inet_connection_sock *newicsk = inet_csk(newsk); 682 683 newsk->sk_state = TCP_SYN_RECV; 684 newicsk->icsk_bind_hash = NULL; 685 686 inet_sk(newsk)->inet_dport = inet_rsk(req)->rmt_port; 687 inet_sk(newsk)->inet_num = ntohs(inet_rsk(req)->loc_port); 688 inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port; 689 newsk->sk_write_space = sk_stream_write_space; 690 691 newicsk->icsk_retransmits = 0; 692 newicsk->icsk_backoff = 0; 693 newicsk->icsk_probes_out = 0; 694 695 /* Deinitialize accept_queue to trap illegal accesses. */ 696 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue)); 697 698 security_inet_csk_clone(newsk, req); 699 } 700 return newsk; 701 } 702 EXPORT_SYMBOL_GPL(inet_csk_clone_lock); 703 704 /* 705 * At this point, there should be no process reference to this 706 * socket, and thus no user references at all. Therefore we 707 * can assume the socket waitqueue is inactive and nobody will 708 * try to jump onto it. 709 */ 710 void inet_csk_destroy_sock(struct sock *sk) 711 { 712 WARN_ON(sk->sk_state != TCP_CLOSE); 713 WARN_ON(!sock_flag(sk, SOCK_DEAD)); 714 715 /* It cannot be in hash table! */ 716 WARN_ON(!sk_unhashed(sk)); 717 718 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */ 719 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash); 720 721 sk->sk_prot->destroy(sk); 722 723 sk_stream_kill_queues(sk); 724 725 xfrm_sk_free_policy(sk); 726 727 sk_refcnt_debug_release(sk); 728 729 percpu_counter_dec(sk->sk_prot->orphan_count); 730 sock_put(sk); 731 } 732 EXPORT_SYMBOL(inet_csk_destroy_sock); 733 734 /* This function allows to force a closure of a socket after the call to 735 * tcp/dccp_create_openreq_child(). 736 */ 737 void inet_csk_prepare_forced_close(struct sock *sk) 738 __releases(&sk->sk_lock.slock) 739 { 740 /* sk_clone_lock locked the socket and set refcnt to 2 */ 741 bh_unlock_sock(sk); 742 sock_put(sk); 743 744 /* The below has to be done to allow calling inet_csk_destroy_sock */ 745 sock_set_flag(sk, SOCK_DEAD); 746 percpu_counter_inc(sk->sk_prot->orphan_count); 747 inet_sk(sk)->inet_num = 0; 748 } 749 EXPORT_SYMBOL(inet_csk_prepare_forced_close); 750 751 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries) 752 { 753 struct inet_sock *inet = inet_sk(sk); 754 struct inet_connection_sock *icsk = inet_csk(sk); 755 int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries); 756 757 if (rc != 0) 758 return rc; 759 760 sk->sk_max_ack_backlog = 0; 761 sk->sk_ack_backlog = 0; 762 inet_csk_delack_init(sk); 763 764 /* There is race window here: we announce ourselves listening, 765 * but this transition is still not validated by get_port(). 766 * It is OK, because this socket enters to hash table only 767 * after validation is complete. 768 */ 769 sk->sk_state = TCP_LISTEN; 770 if (!sk->sk_prot->get_port(sk, inet->inet_num)) { 771 inet->inet_sport = htons(inet->inet_num); 772 773 sk_dst_reset(sk); 774 sk->sk_prot->hash(sk); 775 776 return 0; 777 } 778 779 sk->sk_state = TCP_CLOSE; 780 __reqsk_queue_destroy(&icsk->icsk_accept_queue); 781 return -EADDRINUSE; 782 } 783 EXPORT_SYMBOL_GPL(inet_csk_listen_start); 784 785 /* 786 * This routine closes sockets which have been at least partially 787 * opened, but not yet accepted. 788 */ 789 void inet_csk_listen_stop(struct sock *sk) 790 { 791 struct inet_connection_sock *icsk = inet_csk(sk); 792 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 793 struct request_sock *acc_req; 794 struct request_sock *req; 795 796 inet_csk_delete_keepalive_timer(sk); 797 798 /* make all the listen_opt local to us */ 799 acc_req = reqsk_queue_yank_acceptq(queue); 800 801 /* Following specs, it would be better either to send FIN 802 * (and enter FIN-WAIT-1, it is normal close) 803 * or to send active reset (abort). 804 * Certainly, it is pretty dangerous while synflood, but it is 805 * bad justification for our negligence 8) 806 * To be honest, we are not able to make either 807 * of the variants now. --ANK 808 */ 809 reqsk_queue_destroy(queue); 810 811 while ((req = acc_req) != NULL) { 812 struct sock *child = req->sk; 813 814 acc_req = req->dl_next; 815 816 local_bh_disable(); 817 bh_lock_sock(child); 818 WARN_ON(sock_owned_by_user(child)); 819 sock_hold(child); 820 821 sk->sk_prot->disconnect(child, O_NONBLOCK); 822 823 sock_orphan(child); 824 825 percpu_counter_inc(sk->sk_prot->orphan_count); 826 827 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->listener) { 828 BUG_ON(tcp_sk(child)->fastopen_rsk != req); 829 BUG_ON(sk != tcp_rsk(req)->listener); 830 831 /* Paranoid, to prevent race condition if 832 * an inbound pkt destined for child is 833 * blocked by sock lock in tcp_v4_rcv(). 834 * Also to satisfy an assertion in 835 * tcp_v4_destroy_sock(). 836 */ 837 tcp_sk(child)->fastopen_rsk = NULL; 838 sock_put(sk); 839 } 840 inet_csk_destroy_sock(child); 841 842 bh_unlock_sock(child); 843 local_bh_enable(); 844 sock_put(child); 845 846 sk_acceptq_removed(sk); 847 __reqsk_free(req); 848 } 849 if (queue->fastopenq != NULL) { 850 /* Free all the reqs queued in rskq_rst_head. */ 851 spin_lock_bh(&queue->fastopenq->lock); 852 acc_req = queue->fastopenq->rskq_rst_head; 853 queue->fastopenq->rskq_rst_head = NULL; 854 spin_unlock_bh(&queue->fastopenq->lock); 855 while ((req = acc_req) != NULL) { 856 acc_req = req->dl_next; 857 __reqsk_free(req); 858 } 859 } 860 WARN_ON(sk->sk_ack_backlog); 861 } 862 EXPORT_SYMBOL_GPL(inet_csk_listen_stop); 863 864 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr) 865 { 866 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr; 867 const struct inet_sock *inet = inet_sk(sk); 868 869 sin->sin_family = AF_INET; 870 sin->sin_addr.s_addr = inet->inet_daddr; 871 sin->sin_port = inet->inet_dport; 872 } 873 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr); 874 875 #ifdef CONFIG_COMPAT 876 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname, 877 char __user *optval, int __user *optlen) 878 { 879 const struct inet_connection_sock *icsk = inet_csk(sk); 880 881 if (icsk->icsk_af_ops->compat_getsockopt != NULL) 882 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname, 883 optval, optlen); 884 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 885 optval, optlen); 886 } 887 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt); 888 889 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname, 890 char __user *optval, unsigned int optlen) 891 { 892 const struct inet_connection_sock *icsk = inet_csk(sk); 893 894 if (icsk->icsk_af_ops->compat_setsockopt != NULL) 895 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname, 896 optval, optlen); 897 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 898 optval, optlen); 899 } 900 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt); 901 #endif 902 903 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl) 904 { 905 const struct inet_sock *inet = inet_sk(sk); 906 const struct ip_options_rcu *inet_opt; 907 __be32 daddr = inet->inet_daddr; 908 struct flowi4 *fl4; 909 struct rtable *rt; 910 911 rcu_read_lock(); 912 inet_opt = rcu_dereference(inet->inet_opt); 913 if (inet_opt && inet_opt->opt.srr) 914 daddr = inet_opt->opt.faddr; 915 fl4 = &fl->u.ip4; 916 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, 917 inet->inet_saddr, inet->inet_dport, 918 inet->inet_sport, sk->sk_protocol, 919 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if); 920 if (IS_ERR(rt)) 921 rt = NULL; 922 if (rt) 923 sk_setup_caps(sk, &rt->dst); 924 rcu_read_unlock(); 925 926 return &rt->dst; 927 } 928 929 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu) 930 { 931 struct dst_entry *dst = __sk_dst_check(sk, 0); 932 struct inet_sock *inet = inet_sk(sk); 933 934 if (!dst) { 935 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 936 if (!dst) 937 goto out; 938 } 939 dst->ops->update_pmtu(dst, sk, NULL, mtu); 940 941 dst = __sk_dst_check(sk, 0); 942 if (!dst) 943 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 944 out: 945 return dst; 946 } 947 EXPORT_SYMBOL_GPL(inet_csk_update_pmtu); 948