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 #include <net/tcp.h> 27 28 #ifdef INET_CSK_DEBUG 29 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n"; 30 EXPORT_SYMBOL(inet_csk_timer_bug_msg); 31 #endif 32 33 void inet_get_local_port_range(struct net *net, int *low, int *high) 34 { 35 unsigned int seq; 36 37 do { 38 seq = read_seqbegin(&net->ipv4.ip_local_ports.lock); 39 40 *low = net->ipv4.ip_local_ports.range[0]; 41 *high = net->ipv4.ip_local_ports.range[1]; 42 } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq)); 43 } 44 EXPORT_SYMBOL(inet_get_local_port_range); 45 46 int inet_csk_bind_conflict(const struct sock *sk, 47 const struct inet_bind_bucket *tb, bool relax) 48 { 49 struct sock *sk2; 50 int reuse = sk->sk_reuse; 51 int reuseport = sk->sk_reuseport; 52 kuid_t uid = sock_i_uid((struct sock *)sk); 53 54 /* 55 * Unlike other sk lookup places we do not check 56 * for sk_net here, since _all_ the socks listed 57 * in tb->owners list belong to the same net - the 58 * one this bucket belongs to. 59 */ 60 61 sk_for_each_bound(sk2, &tb->owners) { 62 if (sk != sk2 && 63 !inet_v6_ipv6only(sk2) && 64 (!sk->sk_bound_dev_if || 65 !sk2->sk_bound_dev_if || 66 sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) { 67 if ((!reuse || !sk2->sk_reuse || 68 sk2->sk_state == TCP_LISTEN) && 69 (!reuseport || !sk2->sk_reuseport || 70 (sk2->sk_state != TCP_TIME_WAIT && 71 !uid_eq(uid, sock_i_uid(sk2))))) { 72 73 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr || 74 sk2->sk_rcv_saddr == sk->sk_rcv_saddr) 75 break; 76 } 77 if (!relax && reuse && sk2->sk_reuse && 78 sk2->sk_state != TCP_LISTEN) { 79 80 if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr || 81 sk2->sk_rcv_saddr == sk->sk_rcv_saddr) 82 break; 83 } 84 } 85 } 86 return sk2 != NULL; 87 } 88 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict); 89 90 /* Obtain a reference to a local port for the given sock, 91 * if snum is zero it means select any available local port. 92 */ 93 int inet_csk_get_port(struct sock *sk, unsigned short snum) 94 { 95 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 96 struct inet_bind_hashbucket *head; 97 struct inet_bind_bucket *tb; 98 int ret, attempts = 5; 99 struct net *net = sock_net(sk); 100 int smallest_size = -1, smallest_rover; 101 kuid_t uid = sock_i_uid(sk); 102 int attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0; 103 104 local_bh_disable(); 105 if (!snum) { 106 int remaining, rover, low, high; 107 108 again: 109 inet_get_local_port_range(net, &low, &high); 110 if (attempt_half) { 111 int half = low + ((high - low) >> 1); 112 113 if (attempt_half == 1) 114 high = half; 115 else 116 low = half; 117 } 118 remaining = (high - low) + 1; 119 smallest_rover = rover = prandom_u32() % remaining + low; 120 121 smallest_size = -1; 122 do { 123 if (inet_is_local_reserved_port(net, rover)) 124 goto next_nolock; 125 head = &hashinfo->bhash[inet_bhashfn(net, rover, 126 hashinfo->bhash_size)]; 127 spin_lock(&head->lock); 128 inet_bind_bucket_for_each(tb, &head->chain) 129 if (net_eq(ib_net(tb), net) && tb->port == rover) { 130 if (((tb->fastreuse > 0 && 131 sk->sk_reuse && 132 sk->sk_state != TCP_LISTEN) || 133 (tb->fastreuseport > 0 && 134 sk->sk_reuseport && 135 uid_eq(tb->fastuid, uid))) && 136 (tb->num_owners < smallest_size || smallest_size == -1)) { 137 smallest_size = tb->num_owners; 138 smallest_rover = rover; 139 } 140 if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) { 141 snum = rover; 142 goto tb_found; 143 } 144 goto next; 145 } 146 break; 147 next: 148 spin_unlock(&head->lock); 149 next_nolock: 150 if (++rover > high) 151 rover = low; 152 } while (--remaining > 0); 153 154 /* Exhausted local port range during search? It is not 155 * possible for us to be holding one of the bind hash 156 * locks if this test triggers, because if 'remaining' 157 * drops to zero, we broke out of the do/while loop at 158 * the top level, not from the 'break;' statement. 159 */ 160 ret = 1; 161 if (remaining <= 0) { 162 if (smallest_size != -1) { 163 snum = smallest_rover; 164 goto have_snum; 165 } 166 if (attempt_half == 1) { 167 /* OK we now try the upper half of the range */ 168 attempt_half = 2; 169 goto again; 170 } 171 goto fail; 172 } 173 /* OK, here is the one we will use. HEAD is 174 * non-NULL and we hold it's mutex. 175 */ 176 snum = rover; 177 } else { 178 have_snum: 179 head = &hashinfo->bhash[inet_bhashfn(net, snum, 180 hashinfo->bhash_size)]; 181 spin_lock(&head->lock); 182 inet_bind_bucket_for_each(tb, &head->chain) 183 if (net_eq(ib_net(tb), net) && tb->port == snum) 184 goto tb_found; 185 } 186 tb = NULL; 187 goto tb_not_found; 188 tb_found: 189 if (!hlist_empty(&tb->owners)) { 190 if (sk->sk_reuse == SK_FORCE_REUSE) 191 goto success; 192 193 if (((tb->fastreuse > 0 && 194 sk->sk_reuse && sk->sk_state != TCP_LISTEN) || 195 (tb->fastreuseport > 0 && 196 sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && 197 smallest_size == -1) { 198 goto success; 199 } else { 200 ret = 1; 201 if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) { 202 if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) || 203 (tb->fastreuseport > 0 && 204 sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && 205 smallest_size != -1 && --attempts >= 0) { 206 spin_unlock(&head->lock); 207 goto again; 208 } 209 210 goto fail_unlock; 211 } 212 } 213 } 214 tb_not_found: 215 ret = 1; 216 if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep, 217 net, head, snum)) == NULL) 218 goto fail_unlock; 219 if (hlist_empty(&tb->owners)) { 220 if (sk->sk_reuse && sk->sk_state != TCP_LISTEN) 221 tb->fastreuse = 1; 222 else 223 tb->fastreuse = 0; 224 if (sk->sk_reuseport) { 225 tb->fastreuseport = 1; 226 tb->fastuid = uid; 227 } else 228 tb->fastreuseport = 0; 229 } else { 230 if (tb->fastreuse && 231 (!sk->sk_reuse || sk->sk_state == TCP_LISTEN)) 232 tb->fastreuse = 0; 233 if (tb->fastreuseport && 234 (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))) 235 tb->fastreuseport = 0; 236 } 237 success: 238 if (!inet_csk(sk)->icsk_bind_hash) 239 inet_bind_hash(sk, tb, snum); 240 WARN_ON(inet_csk(sk)->icsk_bind_hash != tb); 241 ret = 0; 242 243 fail_unlock: 244 spin_unlock(&head->lock); 245 fail: 246 local_bh_enable(); 247 return ret; 248 } 249 EXPORT_SYMBOL_GPL(inet_csk_get_port); 250 251 /* 252 * Wait for an incoming connection, avoid race conditions. This must be called 253 * with the socket locked. 254 */ 255 static int inet_csk_wait_for_connect(struct sock *sk, long timeo) 256 { 257 struct inet_connection_sock *icsk = inet_csk(sk); 258 DEFINE_WAIT(wait); 259 int err; 260 261 /* 262 * True wake-one mechanism for incoming connections: only 263 * one process gets woken up, not the 'whole herd'. 264 * Since we do not 'race & poll' for established sockets 265 * anymore, the common case will execute the loop only once. 266 * 267 * Subtle issue: "add_wait_queue_exclusive()" will be added 268 * after any current non-exclusive waiters, and we know that 269 * it will always _stay_ after any new non-exclusive waiters 270 * because all non-exclusive waiters are added at the 271 * beginning of the wait-queue. As such, it's ok to "drop" 272 * our exclusiveness temporarily when we get woken up without 273 * having to remove and re-insert us on the wait queue. 274 */ 275 for (;;) { 276 prepare_to_wait_exclusive(sk_sleep(sk), &wait, 277 TASK_INTERRUPTIBLE); 278 release_sock(sk); 279 if (reqsk_queue_empty(&icsk->icsk_accept_queue)) 280 timeo = schedule_timeout(timeo); 281 sched_annotate_sleep(); 282 lock_sock(sk); 283 err = 0; 284 if (!reqsk_queue_empty(&icsk->icsk_accept_queue)) 285 break; 286 err = -EINVAL; 287 if (sk->sk_state != TCP_LISTEN) 288 break; 289 err = sock_intr_errno(timeo); 290 if (signal_pending(current)) 291 break; 292 err = -EAGAIN; 293 if (!timeo) 294 break; 295 } 296 finish_wait(sk_sleep(sk), &wait); 297 return err; 298 } 299 300 /* 301 * This will accept the next outstanding connection. 302 */ 303 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err) 304 { 305 struct inet_connection_sock *icsk = inet_csk(sk); 306 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 307 struct request_sock *req; 308 struct sock *newsk; 309 int error; 310 311 lock_sock(sk); 312 313 /* We need to make sure that this socket is listening, 314 * and that it has something pending. 315 */ 316 error = -EINVAL; 317 if (sk->sk_state != TCP_LISTEN) 318 goto out_err; 319 320 /* Find already established connection */ 321 if (reqsk_queue_empty(queue)) { 322 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK); 323 324 /* If this is a non blocking socket don't sleep */ 325 error = -EAGAIN; 326 if (!timeo) 327 goto out_err; 328 329 error = inet_csk_wait_for_connect(sk, timeo); 330 if (error) 331 goto out_err; 332 } 333 req = reqsk_queue_remove(queue); 334 newsk = req->sk; 335 336 sk_acceptq_removed(sk); 337 if (sk->sk_protocol == IPPROTO_TCP && 338 tcp_rsk(req)->tfo_listener && 339 queue->fastopenq) { 340 spin_lock_bh(&queue->fastopenq->lock); 341 if (tcp_rsk(req)->tfo_listener) { 342 /* We are still waiting for the final ACK from 3WHS 343 * so can't free req now. Instead, we set req->sk to 344 * NULL to signify that the child socket is taken 345 * so reqsk_fastopen_remove() will free the req 346 * when 3WHS finishes (or is aborted). 347 */ 348 req->sk = NULL; 349 req = NULL; 350 } 351 spin_unlock_bh(&queue->fastopenq->lock); 352 } 353 out: 354 release_sock(sk); 355 if (req) 356 reqsk_put(req); 357 return newsk; 358 out_err: 359 newsk = NULL; 360 req = NULL; 361 *err = error; 362 goto out; 363 } 364 EXPORT_SYMBOL(inet_csk_accept); 365 366 /* 367 * Using different timers for retransmit, delayed acks and probes 368 * We may wish use just one timer maintaining a list of expire jiffies 369 * to optimize. 370 */ 371 void inet_csk_init_xmit_timers(struct sock *sk, 372 void (*retransmit_handler)(unsigned long), 373 void (*delack_handler)(unsigned long), 374 void (*keepalive_handler)(unsigned long)) 375 { 376 struct inet_connection_sock *icsk = inet_csk(sk); 377 378 setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler, 379 (unsigned long)sk); 380 setup_timer(&icsk->icsk_delack_timer, delack_handler, 381 (unsigned long)sk); 382 setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk); 383 icsk->icsk_pending = icsk->icsk_ack.pending = 0; 384 } 385 EXPORT_SYMBOL(inet_csk_init_xmit_timers); 386 387 void inet_csk_clear_xmit_timers(struct sock *sk) 388 { 389 struct inet_connection_sock *icsk = inet_csk(sk); 390 391 icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0; 392 393 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 394 sk_stop_timer(sk, &icsk->icsk_delack_timer); 395 sk_stop_timer(sk, &sk->sk_timer); 396 } 397 EXPORT_SYMBOL(inet_csk_clear_xmit_timers); 398 399 void inet_csk_delete_keepalive_timer(struct sock *sk) 400 { 401 sk_stop_timer(sk, &sk->sk_timer); 402 } 403 EXPORT_SYMBOL(inet_csk_delete_keepalive_timer); 404 405 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len) 406 { 407 sk_reset_timer(sk, &sk->sk_timer, jiffies + len); 408 } 409 EXPORT_SYMBOL(inet_csk_reset_keepalive_timer); 410 411 struct dst_entry *inet_csk_route_req(struct sock *sk, 412 struct flowi4 *fl4, 413 const struct request_sock *req) 414 { 415 const struct inet_request_sock *ireq = inet_rsk(req); 416 struct net *net = read_pnet(&ireq->ireq_net); 417 struct ip_options_rcu *opt = ireq->opt; 418 struct rtable *rt; 419 420 flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark, 421 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 422 sk->sk_protocol, inet_sk_flowi_flags(sk), 423 (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr, 424 ireq->ir_loc_addr, ireq->ir_rmt_port, 425 htons(ireq->ir_num)); 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 net *net = read_pnet(&ireq->ireq_net); 448 struct inet_sock *newinet = inet_sk(newsk); 449 struct ip_options_rcu *opt; 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, ireq->ir_iif, ireq->ir_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->ir_rmt_addr, 461 ireq->ir_loc_addr, ireq->ir_rmt_port, 462 htons(ireq->ir_num)); 463 security_req_classify_flow(req, flowi4_to_flowi(fl4)); 464 rt = ip_route_output_flow(net, fl4, sk); 465 if (IS_ERR(rt)) 466 goto no_route; 467 if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway) 468 goto route_err; 469 rcu_read_unlock(); 470 return &rt->dst; 471 472 route_err: 473 ip_rt_put(rt); 474 no_route: 475 rcu_read_unlock(); 476 IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES); 477 return NULL; 478 } 479 EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); 480 481 static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport, 482 const u32 rnd, const u32 synq_hsize) 483 { 484 return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1); 485 } 486 487 #if IS_ENABLED(CONFIG_IPV6) 488 #define AF_INET_FAMILY(fam) ((fam) == AF_INET) 489 #else 490 #define AF_INET_FAMILY(fam) true 491 #endif 492 493 /* Note: this is temporary : 494 * req sock will no longer be in listener hash table 495 */ 496 struct request_sock *inet_csk_search_req(struct sock *sk, 497 const __be16 rport, 498 const __be32 raddr, 499 const __be32 laddr) 500 { 501 struct inet_connection_sock *icsk = inet_csk(sk); 502 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; 503 struct request_sock *req; 504 u32 hash = inet_synq_hash(raddr, rport, lopt->hash_rnd, 505 lopt->nr_table_entries); 506 507 spin_lock(&icsk->icsk_accept_queue.syn_wait_lock); 508 for (req = lopt->syn_table[hash]; req != NULL; req = req->dl_next) { 509 const struct inet_request_sock *ireq = inet_rsk(req); 510 511 if (ireq->ir_rmt_port == rport && 512 ireq->ir_rmt_addr == raddr && 513 ireq->ir_loc_addr == laddr && 514 AF_INET_FAMILY(req->rsk_ops->family)) { 515 atomic_inc(&req->rsk_refcnt); 516 WARN_ON(req->sk); 517 break; 518 } 519 } 520 spin_unlock(&icsk->icsk_accept_queue.syn_wait_lock); 521 522 return req; 523 } 524 EXPORT_SYMBOL_GPL(inet_csk_search_req); 525 526 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, 527 unsigned long timeout) 528 { 529 struct inet_connection_sock *icsk = inet_csk(sk); 530 struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; 531 const u32 h = inet_synq_hash(inet_rsk(req)->ir_rmt_addr, 532 inet_rsk(req)->ir_rmt_port, 533 lopt->hash_rnd, lopt->nr_table_entries); 534 535 reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout); 536 inet_csk_reqsk_queue_added(sk, timeout); 537 } 538 EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); 539 540 /* Only thing we need from tcp.h */ 541 extern int sysctl_tcp_synack_retries; 542 543 544 /* Decide when to expire the request and when to resend SYN-ACK */ 545 static inline void syn_ack_recalc(struct request_sock *req, const int thresh, 546 const int max_retries, 547 const u8 rskq_defer_accept, 548 int *expire, int *resend) 549 { 550 if (!rskq_defer_accept) { 551 *expire = req->num_timeout >= thresh; 552 *resend = 1; 553 return; 554 } 555 *expire = req->num_timeout >= thresh && 556 (!inet_rsk(req)->acked || req->num_timeout >= max_retries); 557 /* 558 * Do not resend while waiting for data after ACK, 559 * start to resend on end of deferring period to give 560 * last chance for data or ACK to create established socket. 561 */ 562 *resend = !inet_rsk(req)->acked || 563 req->num_timeout >= rskq_defer_accept - 1; 564 } 565 566 int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req) 567 { 568 int err = req->rsk_ops->rtx_syn_ack(parent, req); 569 570 if (!err) 571 req->num_retrans++; 572 return err; 573 } 574 EXPORT_SYMBOL(inet_rtx_syn_ack); 575 576 /* return true if req was found in the syn_table[] */ 577 static bool reqsk_queue_unlink(struct request_sock_queue *queue, 578 struct request_sock *req) 579 { 580 struct listen_sock *lopt = queue->listen_opt; 581 struct request_sock **prev; 582 bool found = false; 583 584 spin_lock(&queue->syn_wait_lock); 585 586 for (prev = &lopt->syn_table[req->rsk_hash]; *prev != NULL; 587 prev = &(*prev)->dl_next) { 588 if (*prev == req) { 589 *prev = req->dl_next; 590 found = true; 591 break; 592 } 593 } 594 595 spin_unlock(&queue->syn_wait_lock); 596 if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer)) 597 reqsk_put(req); 598 return found; 599 } 600 601 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req) 602 { 603 if (reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req)) { 604 reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req); 605 reqsk_put(req); 606 } 607 } 608 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop); 609 610 static void reqsk_timer_handler(unsigned long data) 611 { 612 struct request_sock *req = (struct request_sock *)data; 613 struct sock *sk_listener = req->rsk_listener; 614 struct inet_connection_sock *icsk = inet_csk(sk_listener); 615 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 616 struct listen_sock *lopt = queue->listen_opt; 617 int qlen, expire = 0, resend = 0; 618 int max_retries, thresh; 619 u8 defer_accept; 620 621 if (sk_listener->sk_state != TCP_LISTEN || !lopt) { 622 reqsk_put(req); 623 return; 624 } 625 626 max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries; 627 thresh = max_retries; 628 /* Normally all the openreqs are young and become mature 629 * (i.e. converted to established socket) for first timeout. 630 * If synack was not acknowledged for 1 second, it means 631 * one of the following things: synack was lost, ack was lost, 632 * rtt is high or nobody planned to ack (i.e. synflood). 633 * When server is a bit loaded, queue is populated with old 634 * open requests, reducing effective size of queue. 635 * When server is well loaded, queue size reduces to zero 636 * after several minutes of work. It is not synflood, 637 * it is normal operation. The solution is pruning 638 * too old entries overriding normal timeout, when 639 * situation becomes dangerous. 640 * 641 * Essentially, we reserve half of room for young 642 * embrions; and abort old ones without pity, if old 643 * ones are about to clog our table. 644 */ 645 qlen = listen_sock_qlen(lopt); 646 if (qlen >> (lopt->max_qlen_log - 1)) { 647 int young = listen_sock_young(lopt) << 1; 648 649 while (thresh > 2) { 650 if (qlen < young) 651 break; 652 thresh--; 653 young <<= 1; 654 } 655 } 656 defer_accept = READ_ONCE(queue->rskq_defer_accept); 657 if (defer_accept) 658 max_retries = defer_accept; 659 syn_ack_recalc(req, thresh, max_retries, defer_accept, 660 &expire, &resend); 661 req->rsk_ops->syn_ack_timeout(req); 662 if (!expire && 663 (!resend || 664 !inet_rtx_syn_ack(sk_listener, req) || 665 inet_rsk(req)->acked)) { 666 unsigned long timeo; 667 668 if (req->num_timeout++ == 0) 669 atomic_inc(&lopt->young_dec); 670 timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX); 671 mod_timer_pinned(&req->rsk_timer, jiffies + timeo); 672 return; 673 } 674 inet_csk_reqsk_queue_drop(sk_listener, req); 675 reqsk_put(req); 676 } 677 678 void reqsk_queue_hash_req(struct request_sock_queue *queue, 679 u32 hash, struct request_sock *req, 680 unsigned long timeout) 681 { 682 struct listen_sock *lopt = queue->listen_opt; 683 684 req->num_retrans = 0; 685 req->num_timeout = 0; 686 req->sk = NULL; 687 688 /* before letting lookups find us, make sure all req fields 689 * are committed to memory and refcnt initialized. 690 */ 691 smp_wmb(); 692 atomic_set(&req->rsk_refcnt, 2); 693 setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req); 694 req->rsk_hash = hash; 695 696 spin_lock(&queue->syn_wait_lock); 697 req->dl_next = lopt->syn_table[hash]; 698 lopt->syn_table[hash] = req; 699 spin_unlock(&queue->syn_wait_lock); 700 701 mod_timer_pinned(&req->rsk_timer, jiffies + timeout); 702 } 703 EXPORT_SYMBOL(reqsk_queue_hash_req); 704 705 /** 706 * inet_csk_clone_lock - clone an inet socket, and lock its clone 707 * @sk: the socket to clone 708 * @req: request_sock 709 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc) 710 * 711 * Caller must unlock socket even in error path (bh_unlock_sock(newsk)) 712 */ 713 struct sock *inet_csk_clone_lock(const struct sock *sk, 714 const struct request_sock *req, 715 const gfp_t priority) 716 { 717 struct sock *newsk = sk_clone_lock(sk, priority); 718 719 if (newsk) { 720 struct inet_connection_sock *newicsk = inet_csk(newsk); 721 722 newsk->sk_state = TCP_SYN_RECV; 723 newicsk->icsk_bind_hash = NULL; 724 725 inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port; 726 inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num; 727 inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num); 728 newsk->sk_write_space = sk_stream_write_space; 729 730 newsk->sk_mark = inet_rsk(req)->ir_mark; 731 atomic64_set(&newsk->sk_cookie, 732 atomic64_read(&inet_rsk(req)->ir_cookie)); 733 734 newicsk->icsk_retransmits = 0; 735 newicsk->icsk_backoff = 0; 736 newicsk->icsk_probes_out = 0; 737 738 /* Deinitialize accept_queue to trap illegal accesses. */ 739 memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue)); 740 741 security_inet_csk_clone(newsk, req); 742 } 743 return newsk; 744 } 745 EXPORT_SYMBOL_GPL(inet_csk_clone_lock); 746 747 /* 748 * At this point, there should be no process reference to this 749 * socket, and thus no user references at all. Therefore we 750 * can assume the socket waitqueue is inactive and nobody will 751 * try to jump onto it. 752 */ 753 void inet_csk_destroy_sock(struct sock *sk) 754 { 755 WARN_ON(sk->sk_state != TCP_CLOSE); 756 WARN_ON(!sock_flag(sk, SOCK_DEAD)); 757 758 /* It cannot be in hash table! */ 759 WARN_ON(!sk_unhashed(sk)); 760 761 /* If it has not 0 inet_sk(sk)->inet_num, it must be bound */ 762 WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash); 763 764 sk->sk_prot->destroy(sk); 765 766 sk_stream_kill_queues(sk); 767 768 xfrm_sk_free_policy(sk); 769 770 sk_refcnt_debug_release(sk); 771 772 percpu_counter_dec(sk->sk_prot->orphan_count); 773 sock_put(sk); 774 } 775 EXPORT_SYMBOL(inet_csk_destroy_sock); 776 777 /* This function allows to force a closure of a socket after the call to 778 * tcp/dccp_create_openreq_child(). 779 */ 780 void inet_csk_prepare_forced_close(struct sock *sk) 781 __releases(&sk->sk_lock.slock) 782 { 783 /* sk_clone_lock locked the socket and set refcnt to 2 */ 784 bh_unlock_sock(sk); 785 sock_put(sk); 786 787 /* The below has to be done to allow calling inet_csk_destroy_sock */ 788 sock_set_flag(sk, SOCK_DEAD); 789 percpu_counter_inc(sk->sk_prot->orphan_count); 790 inet_sk(sk)->inet_num = 0; 791 } 792 EXPORT_SYMBOL(inet_csk_prepare_forced_close); 793 794 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries) 795 { 796 struct inet_sock *inet = inet_sk(sk); 797 struct inet_connection_sock *icsk = inet_csk(sk); 798 int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries); 799 800 if (rc != 0) 801 return rc; 802 803 sk->sk_max_ack_backlog = 0; 804 sk->sk_ack_backlog = 0; 805 inet_csk_delack_init(sk); 806 807 /* There is race window here: we announce ourselves listening, 808 * but this transition is still not validated by get_port(). 809 * It is OK, because this socket enters to hash table only 810 * after validation is complete. 811 */ 812 sk->sk_state = TCP_LISTEN; 813 if (!sk->sk_prot->get_port(sk, inet->inet_num)) { 814 inet->inet_sport = htons(inet->inet_num); 815 816 sk_dst_reset(sk); 817 sk->sk_prot->hash(sk); 818 819 return 0; 820 } 821 822 sk->sk_state = TCP_CLOSE; 823 __reqsk_queue_destroy(&icsk->icsk_accept_queue); 824 return -EADDRINUSE; 825 } 826 EXPORT_SYMBOL_GPL(inet_csk_listen_start); 827 828 /* 829 * This routine closes sockets which have been at least partially 830 * opened, but not yet accepted. 831 */ 832 void inet_csk_listen_stop(struct sock *sk) 833 { 834 struct inet_connection_sock *icsk = inet_csk(sk); 835 struct request_sock_queue *queue = &icsk->icsk_accept_queue; 836 struct request_sock *acc_req; 837 struct request_sock *req; 838 839 /* make all the listen_opt local to us */ 840 acc_req = reqsk_queue_yank_acceptq(queue); 841 842 /* Following specs, it would be better either to send FIN 843 * (and enter FIN-WAIT-1, it is normal close) 844 * or to send active reset (abort). 845 * Certainly, it is pretty dangerous while synflood, but it is 846 * bad justification for our negligence 8) 847 * To be honest, we are not able to make either 848 * of the variants now. --ANK 849 */ 850 reqsk_queue_destroy(queue); 851 852 while ((req = acc_req) != NULL) { 853 struct sock *child = req->sk; 854 855 acc_req = req->dl_next; 856 857 local_bh_disable(); 858 bh_lock_sock(child); 859 WARN_ON(sock_owned_by_user(child)); 860 sock_hold(child); 861 862 sk->sk_prot->disconnect(child, O_NONBLOCK); 863 864 sock_orphan(child); 865 866 percpu_counter_inc(sk->sk_prot->orphan_count); 867 868 if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) { 869 BUG_ON(tcp_sk(child)->fastopen_rsk != req); 870 BUG_ON(sk != req->rsk_listener); 871 872 /* Paranoid, to prevent race condition if 873 * an inbound pkt destined for child is 874 * blocked by sock lock in tcp_v4_rcv(). 875 * Also to satisfy an assertion in 876 * tcp_v4_destroy_sock(). 877 */ 878 tcp_sk(child)->fastopen_rsk = NULL; 879 } 880 inet_csk_destroy_sock(child); 881 882 bh_unlock_sock(child); 883 local_bh_enable(); 884 sock_put(child); 885 886 sk_acceptq_removed(sk); 887 reqsk_put(req); 888 } 889 if (queue->fastopenq) { 890 /* Free all the reqs queued in rskq_rst_head. */ 891 spin_lock_bh(&queue->fastopenq->lock); 892 acc_req = queue->fastopenq->rskq_rst_head; 893 queue->fastopenq->rskq_rst_head = NULL; 894 spin_unlock_bh(&queue->fastopenq->lock); 895 while ((req = acc_req) != NULL) { 896 acc_req = req->dl_next; 897 reqsk_put(req); 898 } 899 } 900 WARN_ON(sk->sk_ack_backlog); 901 } 902 EXPORT_SYMBOL_GPL(inet_csk_listen_stop); 903 904 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr) 905 { 906 struct sockaddr_in *sin = (struct sockaddr_in *)uaddr; 907 const struct inet_sock *inet = inet_sk(sk); 908 909 sin->sin_family = AF_INET; 910 sin->sin_addr.s_addr = inet->inet_daddr; 911 sin->sin_port = inet->inet_dport; 912 } 913 EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr); 914 915 #ifdef CONFIG_COMPAT 916 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname, 917 char __user *optval, int __user *optlen) 918 { 919 const struct inet_connection_sock *icsk = inet_csk(sk); 920 921 if (icsk->icsk_af_ops->compat_getsockopt) 922 return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname, 923 optval, optlen); 924 return icsk->icsk_af_ops->getsockopt(sk, level, optname, 925 optval, optlen); 926 } 927 EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt); 928 929 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname, 930 char __user *optval, unsigned int optlen) 931 { 932 const struct inet_connection_sock *icsk = inet_csk(sk); 933 934 if (icsk->icsk_af_ops->compat_setsockopt) 935 return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname, 936 optval, optlen); 937 return icsk->icsk_af_ops->setsockopt(sk, level, optname, 938 optval, optlen); 939 } 940 EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt); 941 #endif 942 943 static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl) 944 { 945 const struct inet_sock *inet = inet_sk(sk); 946 const struct ip_options_rcu *inet_opt; 947 __be32 daddr = inet->inet_daddr; 948 struct flowi4 *fl4; 949 struct rtable *rt; 950 951 rcu_read_lock(); 952 inet_opt = rcu_dereference(inet->inet_opt); 953 if (inet_opt && inet_opt->opt.srr) 954 daddr = inet_opt->opt.faddr; 955 fl4 = &fl->u.ip4; 956 rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, 957 inet->inet_saddr, inet->inet_dport, 958 inet->inet_sport, sk->sk_protocol, 959 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if); 960 if (IS_ERR(rt)) 961 rt = NULL; 962 if (rt) 963 sk_setup_caps(sk, &rt->dst); 964 rcu_read_unlock(); 965 966 return &rt->dst; 967 } 968 969 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu) 970 { 971 struct dst_entry *dst = __sk_dst_check(sk, 0); 972 struct inet_sock *inet = inet_sk(sk); 973 974 if (!dst) { 975 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 976 if (!dst) 977 goto out; 978 } 979 dst->ops->update_pmtu(dst, sk, NULL, mtu); 980 981 dst = __sk_dst_check(sk, 0); 982 if (!dst) 983 dst = inet_csk_rebuild_route(sk, &inet->cork.fl); 984 out: 985 return dst; 986 } 987 EXPORT_SYMBOL_GPL(inet_csk_update_pmtu); 988