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 unsigned long *sysctl_local_reserved_ports; 33 EXPORT_SYMBOL(sysctl_local_reserved_ports); 34 35 void inet_get_local_port_range(struct net *net, int *low, int *high) 36 { 37 unsigned int seq; 38 39 do { 40 seq = read_seqbegin(&net->ipv4.sysctl_local_ports.lock); 41 42 *low = net->ipv4.sysctl_local_ports.range[0]; 43 *high = net->ipv4.sysctl_local_ports.range[1]; 44 } while (read_seqretry(&net->ipv4.sysctl_local_ports.lock, seq)); 45 } 46 EXPORT_SYMBOL(inet_get_local_port_range); 47 48 int inet_csk_bind_conflict(const struct sock *sk, 49 const struct inet_bind_bucket *tb, bool relax) 50 { 51 struct sock *sk2; 52 int reuse = sk->sk_reuse; 53 int reuseport = sk->sk_reuseport; 54 kuid_t uid = sock_i_uid((struct sock *)sk); 55 56 /* 57 * Unlike other sk lookup places we do not check 58 * for sk_net here, since _all_ the socks listed 59 * in tb->owners list belong to the same net - the 60 * one this bucket belongs to. 61 */ 62 63 sk_for_each_bound(sk2, &tb->owners) { 64 if (sk != sk2 && 65 !inet_v6_ipv6only(sk2) && 66 (!sk->sk_bound_dev_if || 67 !sk2->sk_bound_dev_if || 68 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) { 69 if ((!reuse || !sk2->sk_reuse || 70 sk2->sk_state == TCP_LISTEN) && 71 (!reuseport || !sk2->sk_reuseport || 72 (sk2->sk_state != TCP_TIME_WAIT && 73 !uid_eq(uid, sock_i_uid(sk2))))) { 74 75 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr || 76 sk2->sk_rcv_saddr == sk->sk_rcv_saddr) 77 break; 78 } 79 if (!relax && reuse && sk2->sk_reuse && 80 sk2->sk_state != TCP_LISTEN) { 81 82 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr || 83 sk2->sk_rcv_saddr == sk->sk_rcv_saddr) 84 break; 85 } 86 } 87 } 88 return sk2 != NULL; 89 } 90 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict); 91 92 /* Obtain a reference to a local port for the given sock, 93 * if snum is zero it means select any available local port. 94 */ 95 int inet_csk_get_port(struct sock *sk, unsigned short snum) 96 { 97 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 98 struct inet_bind_hashbucket *head; 99 struct inet_bind_bucket *tb; 100 int ret, attempts = 5; 101 struct net *net = sock_net(sk); 102 int smallest_size = -1, smallest_rover; 103 kuid_t uid = sock_i_uid(sk); 104 105 local_bh_disable(); 106 if (!snum) { 107 int remaining, rover, low, high; 108 109 again: 110 inet_get_local_port_range(net, &low, &high); 111 remaining = (high - low) + 1; 112 smallest_rover = rover = net_random() % remaining + low; 113 114 smallest_size = -1; 115 do { 116 if (inet_is_reserved_local_port(rover)) 117 goto next_nolock; 118 head = &hashinfo->bhash[inet_bhashfn(net, rover, 119 hashinfo->bhash_size)]; 120 spin_lock(&head->lock); 121 inet_bind_bucket_for_each(tb, &head->chain) 122 if (net_eq(ib_net(tb), net) && tb->port == rover) { 123 if (((tb->fastreuse > 0 && 124 sk->sk_reuse && 125 sk->sk_state != TCP_LISTEN) || 126 (tb->fastreuseport > 0 && 127 sk->sk_reuseport && 128 uid_eq(tb->fastuid, uid))) && 129 (tb->num_owners < smallest_size || smallest_size == -1)) { 130 smallest_size = tb->num_owners; 131 smallest_rover = rover; 132 if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 && 133 !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) { 134 snum = smallest_rover; 135 goto tb_found; 136 } 137 } 138 if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) { 139 snum = rover; 140 goto tb_found; 141 } 142 goto next; 143 } 144 break; 145 next: 146 spin_unlock(&head->lock); 147 next_nolock: 148 if (++rover > high) 149 rover = low; 150 } while (--remaining > 0); 151 152 /* Exhausted local port range during search? It is not 153 * possible for us to be holding one of the bind hash 154 * locks if this test triggers, because if 'remaining' 155 * drops to zero, we broke out of the do/while loop at 156 * the top level, not from the 'break;' statement. 157 */ 158 ret = 1; 159 if (remaining <= 0) { 160 if (smallest_size != -1) { 161 snum = smallest_rover; 162 goto have_snum; 163 } 164 goto fail; 165 } 166 /* OK, here is the one we will use. HEAD is 167 * non-NULL and we hold it's mutex. 168 */ 169 snum = rover; 170 } else { 171 have_snum: 172 head = &hashinfo->bhash[inet_bhashfn(net, snum, 173 hashinfo->bhash_size)]; 174 spin_lock(&head->lock); 175 inet_bind_bucket_for_each(tb, &head->chain) 176 if (net_eq(ib_net(tb), net) && tb->port == snum) 177 goto tb_found; 178 } 179 tb = NULL; 180 goto tb_not_found; 181 tb_found: 182 if (!hlist_empty(&tb->owners)) { 183 if (sk->sk_reuse == SK_FORCE_REUSE) 184 goto success; 185 186 if (((tb->fastreuse > 0 && 187 sk->sk_reuse && sk->sk_state != TCP_LISTEN) || 188 (tb->fastreuseport > 0 && 189 sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && 190 smallest_size == -1) { 191 goto success; 192 } else { 193 ret = 1; 194 if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) { 195 if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) || 196 (tb->fastreuseport > 0 && 197 sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && 198 smallest_size != -1 && --attempts >= 0) { 199 spin_unlock(&head->lock); 200 goto again; 201 } 202 203 goto fail_unlock; 204 } 205 } 206 } 207 tb_not_found: 208 ret = 1; 209 if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep, 210 net, head, snum)) == NULL) 211 goto fail_unlock; 212 if (hlist_empty(&tb->owners)) { 213 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN) 214 tb->fastreuse = 1; 215 else 216 tb->fastreuse = 0; 217 if (sk->sk_reuseport) { 218 tb->fastreuseport = 1; 219 tb->fastuid = uid; 220 } else 221 tb->fastreuseport = 0; 222 } else { 223 if (tb->fastreuse && 224 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN)) 225 tb->fastreuse = 0; 226 if (tb->fastreuseport && 227 (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))) 228 tb->fastreuseport = 0; 229 } 230 success: 231 if (!inet_csk(sk)->icsk_bind_hash) 232 inet_bind_hash(sk, tb, snum); 233 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); 234 ret = 0; 235 236 fail_unlock: 237 spin_unlock(&head->lock); 238 fail: 239 local_bh_enable(); 240 return ret; 241 } 242 EXPORT_SYMBOL_GPL(inet_csk_get_port); 243 244 /* 245 * Wait for an incoming connection, avoid race conditions. This must be called 246 * with the socket locked. 247 */ 248 static int inet_csk_wait_for_connect(struct sock *sk, long timeo) 249 { 250 struct inet_connection_sock *icsk = inet_csk(sk); 251 DEFINE_WAIT(wait); 252 int err; 253 254 /* 255 * True wake-one mechanism for incoming connections: only 256 * one process gets woken up, not the 'whole herd'. 257 * Since we do not 'race & poll' for established sockets 258 * anymore, the common case will execute the loop only once. 259 * 260 * Subtle issue: "add_wait_queue_exclusive()" will be added 261 * after any current non-exclusive waiters, and we know that 262 * it will always _stay_ after any new non-exclusive waiters 263 * because all non-exclusive waiters are added at the 264 * beginning of the wait-queue. As such, it's ok to "drop" 265 * our exclusiveness temporarily when we get woken up without 266 * having to remove and re-insert us on the wait queue. 267 */ 268 for (;;) { 269 prepare_to_wait_exclusive(sk_sleep(sk), &wait, 270 TASK_INTERRUPTIBLE); 271 release_sock(sk); 272 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) 273 timeo = schedule_timeout(timeo); 274 lock_sock(sk); 275 err = 0; 276 if (!reqsk_queue_empty(&icsk->icsk_accept_queue)) 277 break; 278 err = -EINVAL; 279 if (sk->sk_state != TCP_LISTEN) 280 break; 281 err = sock_intr_errno(timeo); 282 if (signal_pending(current)) 283 break; 284 err = -EAGAIN; 285 if (!timeo) 286 break; 287 } 288 finish_wait(sk_sleep(sk), &wait); 289 return err; 290 } 291 292 /* 293 * This will accept the next outstanding connection. 294 */ 295 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err) 296 { 297 struct inet_connection_sock *icsk = inet_csk(sk); 298 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 299 struct sock *newsk; 300 struct request_sock *req; 301 int error; 302 303 lock_sock(sk); 304 305 /* We need to make sure that this socket is listening, 306 * and that it has something pending. 307 */ 308 error = -EINVAL; 309 if (sk->sk_state != TCP_LISTEN) 310 goto out_err; 311 312 /* Find already established connection */ 313 if (reqsk_queue_empty(queue)) { 314 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK); 315 316 /* If this is a non blocking socket don't sleep */ 317 error = -EAGAIN; 318 if (!timeo) 319 goto out_err; 320 321 error = inet_csk_wait_for_connect(sk, timeo); 322 if (error) 323 goto out_err; 324 } 325 req = reqsk_queue_remove(queue); 326 newsk = req->sk; 327 328 sk_acceptq_removed(sk); 329 if (sk->sk_protocol == IPPROTO_TCP && queue->fastopenq != NULL) { 330 spin_lock_bh(&queue->fastopenq->lock); 331 if (tcp_rsk(req)->listener) { 332 /* We are still waiting for the final ACK from 3WHS 333 * so can't free req now. Instead, we set req->sk to 334 * NULL to signify that the child socket is taken 335 * so reqsk_fastopen_remove() will free the req 336 * when 3WHS finishes (or is aborted). 337 */ 338 req->sk = NULL; 339 req = NULL; 340 } 341 spin_unlock_bh(&queue->fastopenq->lock); 342 } 343 out: 344 release_sock(sk); 345 if (req) 346 __reqsk_free(req); 347 return newsk; 348 out_err: 349 newsk = NULL; 350 req = NULL; 351 *err = error; 352 goto out; 353 } 354 EXPORT_SYMBOL(inet_csk_accept); 355 356 /* 357 * Using different timers for retransmit, delayed acks and probes 358 * We may wish use just one timer maintaining a list of expire jiffies 359 * to optimize. 360 */ 361 void inet_csk_init_xmit_timers(struct sock *sk, 362 void (*retransmit_handler)(unsigned long), 363 void (*delack_handler)(unsigned long), 364 void (*keepalive_handler)(unsigned long)) 365 { 366 struct inet_connection_sock *icsk = inet_csk(sk); 367 368 setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler, 369 (unsigned long)sk); 370 setup_timer(&icsk->icsk_delack_timer, delack_handler, 371 (unsigned long)sk); 372 setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk); 373 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 374 } 375 EXPORT_SYMBOL(inet_csk_init_xmit_timers); 376 377 void inet_csk_clear_xmit_timers(struct sock *sk) 378 { 379 struct inet_connection_sock *icsk = inet_csk(sk); 380 381 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0; 382 383 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 384 sk_stop_timer(sk, &icsk->icsk_delack_timer); 385 sk_stop_timer(sk, &sk->sk_timer); 386 } 387 EXPORT_SYMBOL(inet_csk_clear_xmit_timers); 388 389 void inet_csk_delete_keepalive_timer(struct sock *sk) 390 { 391 sk_stop_timer(sk, &sk->sk_timer); 392 } 393 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer); 394 395 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) 396 { 397 sk_reset_timer(sk, &sk->sk_timer, jiffies + len); 398 } 399 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer); 400 401 struct dst_entry *inet_csk_route_req(struct sock *sk, 402 struct flowi4 *fl4, 403 const struct request_sock *req) 404 { 405 struct rtable *rt; 406 const struct inet_request_sock *ireq = inet_rsk(req); 407 struct ip_options_rcu *opt = inet_rsk(req)->opt; 408 struct net *net = sock_net(sk); 409 int flags = inet_sk_flowi_flags(sk); 410 411 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 412 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 413 sk->sk_protocol, 414 flags, 415 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, 416 ireq->ir_loc_addr, ireq->ir_rmt_port, inet_sk(sk)->inet_sport); 417 security_req_classify_flow(req, flowi4_to_flowi(fl4)); 418 rt = ip_route_output_flow(net, fl4, sk); 419 if (IS_ERR(rt)) 420 goto no_route; 421 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 422 goto route_err; 423 return &rt->dst; 424 425 route_err: 426 ip_rt_put(rt); 427 no_route: 428 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES); 429 return NULL; 430 } 431 EXPORT_SYMBOL_GPL(inet_csk_route_req); 432 433 struct dst_entry *inet_csk_route_child_sock(struct sock *sk, 434 struct sock *newsk, 435 const struct request_sock *req) 436 { 437 const struct inet_request_sock *ireq = inet_rsk(req); 438 struct inet_sock *newinet = inet_sk(newsk); 439 struct ip_options_rcu *opt; 440 struct net *net = sock_net(sk); 441 struct flowi4 *fl4; 442 struct rtable *rt; 443 444 fl4 = &newinet->cork.fl.u.ip4; 445 446 rcu_read_lock(); 447 opt = rcu_dereference(newinet->inet_opt); 448 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 449 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 450 sk->sk_protocol, inet_sk_flowi_flags(sk), 451 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, 452 ireq->ir_loc_addr, ireq->ir_rmt_port, inet_sk(sk)->inet_sport); 453 security_req_classify_flow(req, flowi4_to_flowi(fl4)); 454 rt = ip_route_output_flow(net, fl4, sk); 455 if (IS_ERR(rt)) 456 goto no_route; 457 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 458 goto route_err; 459 rcu_read_unlock(); 460 return &rt->dst; 461 462 route_err: 463 ip_rt_put(rt); 464 no_route: 465 rcu_read_unlock(); 466 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES); 467 return NULL; 468 } 469 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); 470 471 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport, 472 const u32 rnd, const u32 synq_hsize) 473 { 474 return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1); 475 } 476 477 #if IS_ENABLED(CONFIG_IPV6) 478 #define AF_INET_FAMILY(fam) ((fam) == AF_INET) 479 #else 480 #define AF_INET_FAMILY(fam) 1 481 #endif 482 483 struct request_sock *inet_csk_search_req(const struct sock *sk, 484 struct request_sock ***prevp, 485 const __be16 rport, const __be32 raddr, 486 const __be32 laddr) 487 { 488 const struct inet_connection_sock *icsk = inet_csk(sk); 489 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; 490 struct request_sock *req, **prev; 491 492 for (prev = &lopt->syn_table[inet_synq_hash(raddr, rport, lopt->hash_rnd, 493 lopt->nr_table_entries)]; 494 (req = *prev) != NULL; 495 prev = &req->dl_next) { 496 const struct inet_request_sock *ireq = inet_rsk(req); 497 498 if (ireq->ir_rmt_port == rport && 499 ireq->ir_rmt_addr == raddr && 500 ireq->ir_loc_addr == laddr && 501 AF_INET_FAMILY(req->rsk_ops->family)) { 502 WARN_ON(req->sk); 503 *prevp = prev; 504 break; 505 } 506 } 507 508 return req; 509 } 510 EXPORT_SYMBOL_GPL(inet_csk_search_req); 511 512 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, 513 unsigned long timeout) 514 { 515 struct inet_connection_sock *icsk = inet_csk(sk); 516 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; 517 const u32 h = inet_synq_hash(inet_rsk(req)->ir_rmt_addr, 518 inet_rsk(req)->ir_rmt_port, 519 lopt->hash_rnd, lopt->nr_table_entries); 520 521 reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout); 522 inet_csk_reqsk_queue_added(sk, timeout); 523 } 524 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); 525 526 /* Only thing we need from tcp.h */ 527 extern int sysctl_tcp_synack_retries; 528 529 530 /* Decide when to expire the request and when to resend SYN-ACK */ 531 static inline void syn_ack_recalc(struct request_sock *req, const int thresh, 532 const int max_retries, 533 const u8 rskq_defer_accept, 534 int *expire, int *resend) 535 { 536 if (!rskq_defer_accept) { 537 *expire = req->num_timeout >= thresh; 538 *resend = 1; 539 return; 540 } 541 *expire = req->num_timeout >= thresh && 542 (!inet_rsk(req)->acked || req->num_timeout >= max_retries); 543 /* 544 * Do not resend while waiting for data after ACK, 545 * start to resend on end of deferring period to give 546 * last chance for data or ACK to create established socket. 547 */ 548 *resend = !inet_rsk(req)->acked || 549 req->num_timeout >= rskq_defer_accept - 1; 550 } 551 552 int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req) 553 { 554 int err = req->rsk_ops->rtx_syn_ack(parent, req); 555 556 if (!err) 557 req->num_retrans++; 558 return err; 559 } 560 EXPORT_SYMBOL(inet_rtx_syn_ack); 561 562 void inet_csk_reqsk_queue_prune(struct sock *parent, 563 const unsigned long interval, 564 const unsigned long timeout, 565 const unsigned long max_rto) 566 { 567 struct inet_connection_sock *icsk = inet_csk(parent); 568 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 569 struct listen_sock *lopt = queue->listen_opt; 570 int max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries; 571 int thresh = max_retries; 572 unsigned long now = jiffies; 573 struct request_sock **reqp, *req; 574 int i, budget; 575 576 if (lopt == NULL || lopt->qlen == 0) 577 return; 578 579 /* Normally all the openreqs are young and become mature 580 * (i.e. converted to established socket) for first timeout. 581 * If synack was not acknowledged for 1 second, it means 582 * one of the following things: synack was lost, ack was lost, 583 * rtt is high or nobody planned to ack (i.e. synflood). 584 * When server is a bit loaded, queue is populated with old 585 * open requests, reducing effective size of queue. 586 * When server is well loaded, queue size reduces to zero 587 * after several minutes of work. It is not synflood, 588 * it is normal operation. The solution is pruning 589 * too old entries overriding normal timeout, when 590 * situation becomes dangerous. 591 * 592 * Essentially, we reserve half of room for young 593 * embrions; and abort old ones without pity, if old 594 * ones are about to clog our table. 595 */ 596 if (lopt->qlen>>(lopt->max_qlen_log-1)) { 597 int young = (lopt->qlen_young<<1); 598 599 while (thresh > 2) { 600 if (lopt->qlen < young) 601 break; 602 thresh--; 603 young <<= 1; 604 } 605 } 606 607 if (queue->rskq_defer_accept) 608 max_retries = queue->rskq_defer_accept; 609 610 budget = 2 * (lopt->nr_table_entries / (timeout / interval)); 611 i = lopt->clock_hand; 612 613 do { 614 reqp=&lopt->syn_table[i]; 615 while ((req = *reqp) != NULL) { 616 if (time_after_eq(now, req->expires)) { 617 int expire = 0, resend = 0; 618 619 syn_ack_recalc(req, thresh, max_retries, 620 queue->rskq_defer_accept, 621 &expire, &resend); 622 req->rsk_ops->syn_ack_timeout(parent, req); 623 if (!expire && 624 (!resend || 625 !inet_rtx_syn_ack(parent, req) || 626 inet_rsk(req)->acked)) { 627 unsigned long timeo; 628 629 if (req->num_timeout++ == 0) 630 lopt->qlen_young--; 631 timeo = min(timeout << req->num_timeout, 632 max_rto); 633 req->expires = now + timeo; 634 reqp = &req->dl_next; 635 continue; 636 } 637 638 /* Drop this request */ 639 inet_csk_reqsk_queue_unlink(parent, req, reqp); 640 reqsk_queue_removed(queue, req); 641 reqsk_free(req); 642 continue; 643 } 644 reqp = &req->dl_next; 645 } 646 647 i = (i + 1) & (lopt->nr_table_entries - 1); 648 649 } while (--budget > 0); 650 651 lopt->clock_hand = i; 652 653 if (lopt->qlen) 654 inet_csk_reset_keepalive_timer(parent, interval); 655 } 656 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_prune); 657 658 /** 659 * inet_csk_clone_lock - clone an inet socket, and lock its clone 660 * @sk: the socket to clone 661 * @req: request_sock 662 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc) 663 * 664 * Caller must unlock socket even in error path (bh_unlock_sock(newsk)) 665 */ 666 struct sock *inet_csk_clone_lock(const struct sock *sk, 667 const struct request_sock *req, 668 const gfp_t priority) 669 { 670 struct sock *newsk = sk_clone_lock(sk, priority); 671 672 if (newsk != NULL) { 673 struct inet_connection_sock *newicsk = inet_csk(newsk); 674 675 newsk->sk_state = TCP_SYN_RECV; 676 newicsk->icsk_bind_hash = NULL; 677 678 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port; 679 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num; 680 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num); 681 newsk->sk_write_space = sk_stream_write_space; 682 683 newicsk->icsk_retransmits = 0; 684 newicsk->icsk_backoff = 0; 685 newicsk->icsk_probes_out = 0; 686 687 /* Deinitialize accept_queue to trap illegal accesses. */ 688 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue)); 689 690 security_inet_csk_clone(newsk, req); 691 } 692 return newsk; 693 } 694 EXPORT_SYMBOL_GPL(inet_csk_clone_lock); 695 696 /* 697 * At this point, there should be no process reference to this 698 * socket, and thus no user references at all. Therefore we 699 * can assume the socket waitqueue is inactive and nobody will 700 * try to jump onto it. 701 */ 702 void inet_csk_destroy_sock(struct sock *sk) 703 { 704 WARN_ON(sk->sk_state != TCP_CLOSE); 705 WARN_ON(!sock_flag(sk, SOCK_DEAD)); 706 707 /* It cannot be in hash table! */ 708 WARN_ON(!sk_unhashed(sk)); 709 710 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */ 711 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash); 712 713 sk->sk_prot->destroy(sk); 714 715 sk_stream_kill_queues(sk); 716 717 xfrm_sk_free_policy(sk); 718 719 sk_refcnt_debug_release(sk); 720 721 percpu_counter_dec(sk->sk_prot->orphan_count); 722 sock_put(sk); 723 } 724 EXPORT_SYMBOL(inet_csk_destroy_sock); 725 726 /* This function allows to force a closure of a socket after the call to 727 * tcp/dccp_create_openreq_child(). 728 */ 729 void inet_csk_prepare_forced_close(struct sock *sk) 730 __releases(&sk->sk_lock.slock) 731 { 732 /* sk_clone_lock locked the socket and set refcnt to 2 */ 733 bh_unlock_sock(sk); 734 sock_put(sk); 735 736 /* The below has to be done to allow calling inet_csk_destroy_sock */ 737 sock_set_flag(sk, SOCK_DEAD); 738 percpu_counter_inc(sk->sk_prot->orphan_count); 739 inet_sk(sk)->inet_num = 0; 740 } 741 EXPORT_SYMBOL(inet_csk_prepare_forced_close); 742 743 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries) 744 { 745 struct inet_sock *inet = inet_sk(sk); 746 struct inet_connection_sock *icsk = inet_csk(sk); 747 int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries); 748 749 if (rc != 0) 750 return rc; 751 752 sk->sk_max_ack_backlog = 0; 753 sk->sk_ack_backlog = 0; 754 inet_csk_delack_init(sk); 755 756 /* There is race window here: we announce ourselves listening, 757 * but this transition is still not validated by get_port(). 758 * It is OK, because this socket enters to hash table only 759 * after validation is complete. 760 */ 761 sk->sk_state = TCP_LISTEN; 762 if (!sk->sk_prot->get_port(sk, inet->inet_num)) { 763 inet->inet_sport = htons(inet->inet_num); 764 765 sk_dst_reset(sk); 766 sk->sk_prot->hash(sk); 767 768 return 0; 769 } 770 771 sk->sk_state = TCP_CLOSE; 772 __reqsk_queue_destroy(&icsk->icsk_accept_queue); 773 return -EADDRINUSE; 774 } 775 EXPORT_SYMBOL_GPL(inet_csk_listen_start); 776 777 /* 778 * This routine closes sockets which have been at least partially 779 * opened, but not yet accepted. 780 */ 781 void inet_csk_listen_stop(struct sock *sk) 782 { 783 struct inet_connection_sock *icsk = inet_csk(sk); 784 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 785 struct request_sock *acc_req; 786 struct request_sock *req; 787 788 inet_csk_delete_keepalive_timer(sk); 789 790 /* make all the listen_opt local to us */ 791 acc_req = reqsk_queue_yank_acceptq(queue); 792 793 /* Following specs, it would be better either to send FIN 794 * (and enter FIN-WAIT-1, it is normal close) 795 * or to send active reset (abort). 796 * Certainly, it is pretty dangerous while synflood, but it is 797 * bad justification for our negligence 8) 798 * To be honest, we are not able to make either 799 * of the variants now. --ANK 800 */ 801 reqsk_queue_destroy(queue); 802 803 while ((req = acc_req) != NULL) { 804 struct sock *child = req->sk; 805 806 acc_req = req->dl_next; 807 808 local_bh_disable(); 809 bh_lock_sock(child); 810 WARN_ON(sock_owned_by_user(child)); 811 sock_hold(child); 812 813 sk->sk_prot->disconnect(child, O_NONBLOCK); 814 815 sock_orphan(child); 816 817 percpu_counter_inc(sk->sk_prot->orphan_count); 818 819 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->listener) { 820 BUG_ON(tcp_sk(child)->fastopen_rsk != req); 821 BUG_ON(sk != tcp_rsk(req)->listener); 822 823 /* Paranoid, to prevent race condition if 824 * an inbound pkt destined for child is 825 * blocked by sock lock in tcp_v4_rcv(). 826 * Also to satisfy an assertion in 827 * tcp_v4_destroy_sock(). 828 */ 829 tcp_sk(child)->fastopen_rsk = NULL; 830 sock_put(sk); 831 } 832 inet_csk_destroy_sock(child); 833 834 bh_unlock_sock(child); 835 local_bh_enable(); 836 sock_put(child); 837 838 sk_acceptq_removed(sk); 839 __reqsk_free(req); 840 } 841 if (queue->fastopenq != NULL) { 842 /* Free all the reqs queued in rskq_rst_head. */ 843 spin_lock_bh(&queue->fastopenq->lock); 844 acc_req = queue->fastopenq->rskq_rst_head; 845 queue->fastopenq->rskq_rst_head = NULL; 846 spin_unlock_bh(&queue->fastopenq->lock); 847 while ((req = acc_req) != NULL) { 848 acc_req = req->dl_next; 849 __reqsk_free(req); 850 } 851 } 852 WARN_ON(sk->sk_ack_backlog); 853 } 854 EXPORT_SYMBOL_GPL(inet_csk_listen_stop); 855 856 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr) 857 { 858 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr; 859 const struct inet_sock *inet = inet_sk(sk); 860 861 sin->sin_family = AF_INET; 862 sin->sin_addr.s_addr = inet->inet_daddr; 863 sin->sin_port = inet->inet_dport; 864 } 865 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr); 866 867 #ifdef CONFIG_COMPAT 868 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname, 869 char __user *optval, int __user *optlen) 870 { 871 const struct inet_connection_sock *icsk = inet_csk(sk); 872 873 if (icsk->icsk_af_ops->compat_getsockopt != NULL) 874 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname, 875 optval, optlen); 876 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 877 optval, optlen); 878 } 879 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt); 880 881 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname, 882 char __user *optval, unsigned int optlen) 883 { 884 const struct inet_connection_sock *icsk = inet_csk(sk); 885 886 if (icsk->icsk_af_ops->compat_setsockopt != NULL) 887 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname, 888 optval, optlen); 889 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 890 optval, optlen); 891 } 892 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt); 893 #endif 894 895 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl) 896 { 897 const struct inet_sock *inet = inet_sk(sk); 898 const struct ip_options_rcu *inet_opt; 899 __be32 daddr = inet->inet_daddr; 900 struct flowi4 *fl4; 901 struct rtable *rt; 902 903 rcu_read_lock(); 904 inet_opt = rcu_dereference(inet->inet_opt); 905 if (inet_opt && inet_opt->opt.srr) 906 daddr = inet_opt->opt.faddr; 907 fl4 = &fl->u.ip4; 908 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, 909 inet->inet_saddr, inet->inet_dport, 910 inet->inet_sport, sk->sk_protocol, 911 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if); 912 if (IS_ERR(rt)) 913 rt = NULL; 914 if (rt) 915 sk_setup_caps(sk, &rt->dst); 916 rcu_read_unlock(); 917 918 return &rt->dst; 919 } 920 921 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu) 922 { 923 struct dst_entry *dst = __sk_dst_check(sk, 0); 924 struct inet_sock *inet = inet_sk(sk); 925 926 if (!dst) { 927 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 928 if (!dst) 929 goto out; 930 } 931 dst->ops->update_pmtu(dst, sk, NULL, mtu); 932 933 dst = __sk_dst_check(sk, 0); 934 if (!dst) 935 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 936 out: 937 return dst; 938 } 939 EXPORT_SYMBOL_GPL(inet_csk_update_pmtu); 940