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 * Implementation of the Transmission Control Protocol(TCP). 7 * 8 * IPv4 specific functions 9 * 10 * 11 * code split from: 12 * linux/ipv4/tcp.c 13 * linux/ipv4/tcp_input.c 14 * linux/ipv4/tcp_output.c 15 * 16 * See tcp.c for author information 17 * 18 * This program is free software; you can redistribute it and/or 19 * modify it under the terms of the GNU General Public License 20 * as published by the Free Software Foundation; either version 21 * 2 of the License, or (at your option) any later version. 22 */ 23 24 /* 25 * Changes: 26 * David S. Miller : New socket lookup architecture. 27 * This code is dedicated to John Dyson. 28 * David S. Miller : Change semantics of established hash, 29 * half is devoted to TIME_WAIT sockets 30 * and the rest go in the other half. 31 * Andi Kleen : Add support for syncookies and fixed 32 * some bugs: ip options weren't passed to 33 * the TCP layer, missed a check for an 34 * ACK bit. 35 * Andi Kleen : Implemented fast path mtu discovery. 36 * Fixed many serious bugs in the 37 * request_sock handling and moved 38 * most of it into the af independent code. 39 * Added tail drop and some other bugfixes. 40 * Added new listen semantics. 41 * Mike McLagan : Routing by source 42 * Juan Jose Ciarlante: ip_dynaddr bits 43 * Andi Kleen: various fixes. 44 * Vitaly E. Lavrov : Transparent proxy revived after year 45 * coma. 46 * Andi Kleen : Fix new listen. 47 * Andi Kleen : Fix accept error reporting. 48 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which 49 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind 50 * a single port at the same time. 51 */ 52 53 #define pr_fmt(fmt) "TCP: " fmt 54 55 #include <linux/bottom_half.h> 56 #include <linux/types.h> 57 #include <linux/fcntl.h> 58 #include <linux/module.h> 59 #include <linux/random.h> 60 #include <linux/cache.h> 61 #include <linux/jhash.h> 62 #include <linux/init.h> 63 #include <linux/times.h> 64 #include <linux/slab.h> 65 66 #include <net/net_namespace.h> 67 #include <net/icmp.h> 68 #include <net/inet_hashtables.h> 69 #include <net/tcp.h> 70 #include <net/transp_v6.h> 71 #include <net/ipv6.h> 72 #include <net/inet_common.h> 73 #include <net/timewait_sock.h> 74 #include <net/xfrm.h> 75 #include <net/secure_seq.h> 76 #include <net/busy_poll.h> 77 78 #include <linux/inet.h> 79 #include <linux/ipv6.h> 80 #include <linux/stddef.h> 81 #include <linux/proc_fs.h> 82 #include <linux/seq_file.h> 83 #include <linux/inetdevice.h> 84 85 #include <crypto/hash.h> 86 #include <linux/scatterlist.h> 87 88 #include <trace/events/tcp.h> 89 90 #ifdef CONFIG_TCP_MD5SIG 91 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 92 __be32 daddr, __be32 saddr, const struct tcphdr *th); 93 #endif 94 95 struct inet_hashinfo tcp_hashinfo; 96 EXPORT_SYMBOL(tcp_hashinfo); 97 98 static u32 tcp_v4_init_seq(const struct sk_buff *skb) 99 { 100 return secure_tcp_seq(ip_hdr(skb)->daddr, 101 ip_hdr(skb)->saddr, 102 tcp_hdr(skb)->dest, 103 tcp_hdr(skb)->source); 104 } 105 106 static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb) 107 { 108 return secure_tcp_ts_off(net, ip_hdr(skb)->daddr, ip_hdr(skb)->saddr); 109 } 110 111 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 112 { 113 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); 114 struct tcp_sock *tp = tcp_sk(sk); 115 116 /* With PAWS, it is safe from the viewpoint 117 of data integrity. Even without PAWS it is safe provided sequence 118 spaces do not overlap i.e. at data rates <= 80Mbit/sec. 119 120 Actually, the idea is close to VJ's one, only timestamp cache is 121 held not per host, but per port pair and TW bucket is used as state 122 holder. 123 124 If TW bucket has been already destroyed we fall back to VJ's scheme 125 and use initial timestamp retrieved from peer table. 126 */ 127 if (tcptw->tw_ts_recent_stamp && 128 (!twp || (sock_net(sk)->ipv4.sysctl_tcp_tw_reuse && 129 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) { 130 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; 131 if (tp->write_seq == 0) 132 tp->write_seq = 1; 133 tp->rx_opt.ts_recent = tcptw->tw_ts_recent; 134 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; 135 sock_hold(sktw); 136 return 1; 137 } 138 139 return 0; 140 } 141 EXPORT_SYMBOL_GPL(tcp_twsk_unique); 142 143 /* This will initiate an outgoing connection. */ 144 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 145 { 146 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; 147 struct inet_sock *inet = inet_sk(sk); 148 struct tcp_sock *tp = tcp_sk(sk); 149 __be16 orig_sport, orig_dport; 150 __be32 daddr, nexthop; 151 struct flowi4 *fl4; 152 struct rtable *rt; 153 int err; 154 struct ip_options_rcu *inet_opt; 155 struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row; 156 157 if (addr_len < sizeof(struct sockaddr_in)) 158 return -EINVAL; 159 160 if (usin->sin_family != AF_INET) 161 return -EAFNOSUPPORT; 162 163 nexthop = daddr = usin->sin_addr.s_addr; 164 inet_opt = rcu_dereference_protected(inet->inet_opt, 165 lockdep_sock_is_held(sk)); 166 if (inet_opt && inet_opt->opt.srr) { 167 if (!daddr) 168 return -EINVAL; 169 nexthop = inet_opt->opt.faddr; 170 } 171 172 orig_sport = inet->inet_sport; 173 orig_dport = usin->sin_port; 174 fl4 = &inet->cork.fl.u.ip4; 175 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, 176 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, 177 IPPROTO_TCP, 178 orig_sport, orig_dport, sk); 179 if (IS_ERR(rt)) { 180 err = PTR_ERR(rt); 181 if (err == -ENETUNREACH) 182 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 183 return err; 184 } 185 186 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 187 ip_rt_put(rt); 188 return -ENETUNREACH; 189 } 190 191 if (!inet_opt || !inet_opt->opt.srr) 192 daddr = fl4->daddr; 193 194 if (!inet->inet_saddr) 195 inet->inet_saddr = fl4->saddr; 196 sk_rcv_saddr_set(sk, inet->inet_saddr); 197 198 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) { 199 /* Reset inherited state */ 200 tp->rx_opt.ts_recent = 0; 201 tp->rx_opt.ts_recent_stamp = 0; 202 if (likely(!tp->repair)) 203 tp->write_seq = 0; 204 } 205 206 inet->inet_dport = usin->sin_port; 207 sk_daddr_set(sk, daddr); 208 209 inet_csk(sk)->icsk_ext_hdr_len = 0; 210 if (inet_opt) 211 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 212 213 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; 214 215 /* Socket identity is still unknown (sport may be zero). 216 * However we set state to SYN-SENT and not releasing socket 217 * lock select source port, enter ourselves into the hash tables and 218 * complete initialization after this. 219 */ 220 tcp_set_state(sk, TCP_SYN_SENT); 221 err = inet_hash_connect(tcp_death_row, sk); 222 if (err) 223 goto failure; 224 225 sk_set_txhash(sk); 226 227 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, 228 inet->inet_sport, inet->inet_dport, sk); 229 if (IS_ERR(rt)) { 230 err = PTR_ERR(rt); 231 rt = NULL; 232 goto failure; 233 } 234 /* OK, now commit destination to socket. */ 235 sk->sk_gso_type = SKB_GSO_TCPV4; 236 sk_setup_caps(sk, &rt->dst); 237 rt = NULL; 238 239 if (likely(!tp->repair)) { 240 if (!tp->write_seq) 241 tp->write_seq = secure_tcp_seq(inet->inet_saddr, 242 inet->inet_daddr, 243 inet->inet_sport, 244 usin->sin_port); 245 tp->tsoffset = secure_tcp_ts_off(sock_net(sk), 246 inet->inet_saddr, 247 inet->inet_daddr); 248 } 249 250 inet->inet_id = tp->write_seq ^ jiffies; 251 252 if (tcp_fastopen_defer_connect(sk, &err)) 253 return err; 254 if (err) 255 goto failure; 256 257 err = tcp_connect(sk); 258 259 if (err) 260 goto failure; 261 262 return 0; 263 264 failure: 265 /* 266 * This unhashes the socket and releases the local port, 267 * if necessary. 268 */ 269 tcp_set_state(sk, TCP_CLOSE); 270 ip_rt_put(rt); 271 sk->sk_route_caps = 0; 272 inet->inet_dport = 0; 273 return err; 274 } 275 EXPORT_SYMBOL(tcp_v4_connect); 276 277 /* 278 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191. 279 * It can be called through tcp_release_cb() if socket was owned by user 280 * at the time tcp_v4_err() was called to handle ICMP message. 281 */ 282 void tcp_v4_mtu_reduced(struct sock *sk) 283 { 284 struct inet_sock *inet = inet_sk(sk); 285 struct dst_entry *dst; 286 u32 mtu; 287 288 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) 289 return; 290 mtu = tcp_sk(sk)->mtu_info; 291 dst = inet_csk_update_pmtu(sk, mtu); 292 if (!dst) 293 return; 294 295 /* Something is about to be wrong... Remember soft error 296 * for the case, if this connection will not able to recover. 297 */ 298 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) 299 sk->sk_err_soft = EMSGSIZE; 300 301 mtu = dst_mtu(dst); 302 303 if (inet->pmtudisc != IP_PMTUDISC_DONT && 304 ip_sk_accept_pmtu(sk) && 305 inet_csk(sk)->icsk_pmtu_cookie > mtu) { 306 tcp_sync_mss(sk, mtu); 307 308 /* Resend the TCP packet because it's 309 * clear that the old packet has been 310 * dropped. This is the new "fast" path mtu 311 * discovery. 312 */ 313 tcp_simple_retransmit(sk); 314 } /* else let the usual retransmit timer handle it */ 315 } 316 EXPORT_SYMBOL(tcp_v4_mtu_reduced); 317 318 static void do_redirect(struct sk_buff *skb, struct sock *sk) 319 { 320 struct dst_entry *dst = __sk_dst_check(sk, 0); 321 322 if (dst) 323 dst->ops->redirect(dst, sk, skb); 324 } 325 326 327 /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */ 328 void tcp_req_err(struct sock *sk, u32 seq, bool abort) 329 { 330 struct request_sock *req = inet_reqsk(sk); 331 struct net *net = sock_net(sk); 332 333 /* ICMPs are not backlogged, hence we cannot get 334 * an established socket here. 335 */ 336 if (seq != tcp_rsk(req)->snt_isn) { 337 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 338 } else if (abort) { 339 /* 340 * Still in SYN_RECV, just remove it silently. 341 * There is no good way to pass the error to the newly 342 * created socket, and POSIX does not want network 343 * errors returned from accept(). 344 */ 345 inet_csk_reqsk_queue_drop(req->rsk_listener, req); 346 tcp_listendrop(req->rsk_listener); 347 } 348 reqsk_put(req); 349 } 350 EXPORT_SYMBOL(tcp_req_err); 351 352 /* 353 * This routine is called by the ICMP module when it gets some 354 * sort of error condition. If err < 0 then the socket should 355 * be closed and the error returned to the user. If err > 0 356 * it's just the icmp type << 8 | icmp code. After adjustment 357 * header points to the first 8 bytes of the tcp header. We need 358 * to find the appropriate port. 359 * 360 * The locking strategy used here is very "optimistic". When 361 * someone else accesses the socket the ICMP is just dropped 362 * and for some paths there is no check at all. 363 * A more general error queue to queue errors for later handling 364 * is probably better. 365 * 366 */ 367 368 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) 369 { 370 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data; 371 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2)); 372 struct inet_connection_sock *icsk; 373 struct tcp_sock *tp; 374 struct inet_sock *inet; 375 const int type = icmp_hdr(icmp_skb)->type; 376 const int code = icmp_hdr(icmp_skb)->code; 377 struct sock *sk; 378 struct sk_buff *skb; 379 struct request_sock *fastopen; 380 u32 seq, snd_una; 381 s32 remaining; 382 u32 delta_us; 383 int err; 384 struct net *net = dev_net(icmp_skb->dev); 385 386 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr, 387 th->dest, iph->saddr, ntohs(th->source), 388 inet_iif(icmp_skb), 0); 389 if (!sk) { 390 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); 391 return; 392 } 393 if (sk->sk_state == TCP_TIME_WAIT) { 394 inet_twsk_put(inet_twsk(sk)); 395 return; 396 } 397 seq = ntohl(th->seq); 398 if (sk->sk_state == TCP_NEW_SYN_RECV) 399 return tcp_req_err(sk, seq, 400 type == ICMP_PARAMETERPROB || 401 type == ICMP_TIME_EXCEEDED || 402 (type == ICMP_DEST_UNREACH && 403 (code == ICMP_NET_UNREACH || 404 code == ICMP_HOST_UNREACH))); 405 406 bh_lock_sock(sk); 407 /* If too many ICMPs get dropped on busy 408 * servers this needs to be solved differently. 409 * We do take care of PMTU discovery (RFC1191) special case : 410 * we can receive locally generated ICMP messages while socket is held. 411 */ 412 if (sock_owned_by_user(sk)) { 413 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)) 414 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); 415 } 416 if (sk->sk_state == TCP_CLOSE) 417 goto out; 418 419 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { 420 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 421 goto out; 422 } 423 424 icsk = inet_csk(sk); 425 tp = tcp_sk(sk); 426 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ 427 fastopen = tp->fastopen_rsk; 428 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; 429 if (sk->sk_state != TCP_LISTEN && 430 !between(seq, snd_una, tp->snd_nxt)) { 431 __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); 432 goto out; 433 } 434 435 switch (type) { 436 case ICMP_REDIRECT: 437 if (!sock_owned_by_user(sk)) 438 do_redirect(icmp_skb, sk); 439 goto out; 440 case ICMP_SOURCE_QUENCH: 441 /* Just silently ignore these. */ 442 goto out; 443 case ICMP_PARAMETERPROB: 444 err = EPROTO; 445 break; 446 case ICMP_DEST_UNREACH: 447 if (code > NR_ICMP_UNREACH) 448 goto out; 449 450 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ 451 /* We are not interested in TCP_LISTEN and open_requests 452 * (SYN-ACKs send out by Linux are always <576bytes so 453 * they should go through unfragmented). 454 */ 455 if (sk->sk_state == TCP_LISTEN) 456 goto out; 457 458 tp->mtu_info = info; 459 if (!sock_owned_by_user(sk)) { 460 tcp_v4_mtu_reduced(sk); 461 } else { 462 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &sk->sk_tsq_flags)) 463 sock_hold(sk); 464 } 465 goto out; 466 } 467 468 err = icmp_err_convert[code].errno; 469 /* check if icmp_skb allows revert of backoff 470 * (see draft-zimmermann-tcp-lcd) */ 471 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH) 472 break; 473 if (seq != tp->snd_una || !icsk->icsk_retransmits || 474 !icsk->icsk_backoff || fastopen) 475 break; 476 477 if (sock_owned_by_user(sk)) 478 break; 479 480 icsk->icsk_backoff--; 481 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : 482 TCP_TIMEOUT_INIT; 483 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX); 484 485 skb = tcp_rtx_queue_head(sk); 486 BUG_ON(!skb); 487 488 tcp_mstamp_refresh(tp); 489 delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp); 490 remaining = icsk->icsk_rto - 491 usecs_to_jiffies(delta_us); 492 493 if (remaining > 0) { 494 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 495 remaining, TCP_RTO_MAX); 496 } else { 497 /* RTO revert clocked out retransmission. 498 * Will retransmit now */ 499 tcp_retransmit_timer(sk); 500 } 501 502 break; 503 case ICMP_TIME_EXCEEDED: 504 err = EHOSTUNREACH; 505 break; 506 default: 507 goto out; 508 } 509 510 switch (sk->sk_state) { 511 case TCP_SYN_SENT: 512 case TCP_SYN_RECV: 513 /* Only in fast or simultaneous open. If a fast open socket is 514 * is already accepted it is treated as a connected one below. 515 */ 516 if (fastopen && !fastopen->sk) 517 break; 518 519 if (!sock_owned_by_user(sk)) { 520 sk->sk_err = err; 521 522 sk->sk_error_report(sk); 523 524 tcp_done(sk); 525 } else { 526 sk->sk_err_soft = err; 527 } 528 goto out; 529 } 530 531 /* If we've already connected we will keep trying 532 * until we time out, or the user gives up. 533 * 534 * rfc1122 4.2.3.9 allows to consider as hard errors 535 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, 536 * but it is obsoleted by pmtu discovery). 537 * 538 * Note, that in modern internet, where routing is unreliable 539 * and in each dark corner broken firewalls sit, sending random 540 * errors ordered by their masters even this two messages finally lose 541 * their original sense (even Linux sends invalid PORT_UNREACHs) 542 * 543 * Now we are in compliance with RFCs. 544 * --ANK (980905) 545 */ 546 547 inet = inet_sk(sk); 548 if (!sock_owned_by_user(sk) && inet->recverr) { 549 sk->sk_err = err; 550 sk->sk_error_report(sk); 551 } else { /* Only an error on timeout */ 552 sk->sk_err_soft = err; 553 } 554 555 out: 556 bh_unlock_sock(sk); 557 sock_put(sk); 558 } 559 560 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr) 561 { 562 struct tcphdr *th = tcp_hdr(skb); 563 564 if (skb->ip_summed == CHECKSUM_PARTIAL) { 565 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); 566 skb->csum_start = skb_transport_header(skb) - skb->head; 567 skb->csum_offset = offsetof(struct tcphdr, check); 568 } else { 569 th->check = tcp_v4_check(skb->len, saddr, daddr, 570 csum_partial(th, 571 th->doff << 2, 572 skb->csum)); 573 } 574 } 575 576 /* This routine computes an IPv4 TCP checksum. */ 577 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) 578 { 579 const struct inet_sock *inet = inet_sk(sk); 580 581 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); 582 } 583 EXPORT_SYMBOL(tcp_v4_send_check); 584 585 /* 586 * This routine will send an RST to the other tcp. 587 * 588 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) 589 * for reset. 590 * Answer: if a packet caused RST, it is not for a socket 591 * existing in our system, if it is matched to a socket, 592 * it is just duplicate segment or bug in other side's TCP. 593 * So that we build reply only basing on parameters 594 * arrived with segment. 595 * Exception: precedence violation. We do not implement it in any case. 596 */ 597 598 static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) 599 { 600 const struct tcphdr *th = tcp_hdr(skb); 601 struct { 602 struct tcphdr th; 603 #ifdef CONFIG_TCP_MD5SIG 604 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)]; 605 #endif 606 } rep; 607 struct ip_reply_arg arg; 608 #ifdef CONFIG_TCP_MD5SIG 609 struct tcp_md5sig_key *key = NULL; 610 const __u8 *hash_location = NULL; 611 unsigned char newhash[16]; 612 int genhash; 613 struct sock *sk1 = NULL; 614 #endif 615 struct net *net; 616 617 /* Never send a reset in response to a reset. */ 618 if (th->rst) 619 return; 620 621 /* If sk not NULL, it means we did a successful lookup and incoming 622 * route had to be correct. prequeue might have dropped our dst. 623 */ 624 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL) 625 return; 626 627 /* Swap the send and the receive. */ 628 memset(&rep, 0, sizeof(rep)); 629 rep.th.dest = th->source; 630 rep.th.source = th->dest; 631 rep.th.doff = sizeof(struct tcphdr) / 4; 632 rep.th.rst = 1; 633 634 if (th->ack) { 635 rep.th.seq = th->ack_seq; 636 } else { 637 rep.th.ack = 1; 638 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + 639 skb->len - (th->doff << 2)); 640 } 641 642 memset(&arg, 0, sizeof(arg)); 643 arg.iov[0].iov_base = (unsigned char *)&rep; 644 arg.iov[0].iov_len = sizeof(rep.th); 645 646 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); 647 #ifdef CONFIG_TCP_MD5SIG 648 rcu_read_lock(); 649 hash_location = tcp_parse_md5sig_option(th); 650 if (sk && sk_fullsock(sk)) { 651 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *) 652 &ip_hdr(skb)->saddr, AF_INET); 653 } else if (hash_location) { 654 /* 655 * active side is lost. Try to find listening socket through 656 * source port, and then find md5 key through listening socket. 657 * we are not loose security here: 658 * Incoming packet is checked with md5 hash with finding key, 659 * no RST generated if md5 hash doesn't match. 660 */ 661 sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0, 662 ip_hdr(skb)->saddr, 663 th->source, ip_hdr(skb)->daddr, 664 ntohs(th->source), inet_iif(skb), 665 tcp_v4_sdif(skb)); 666 /* don't send rst if it can't find key */ 667 if (!sk1) 668 goto out; 669 670 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *) 671 &ip_hdr(skb)->saddr, AF_INET); 672 if (!key) 673 goto out; 674 675 676 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); 677 if (genhash || memcmp(hash_location, newhash, 16) != 0) 678 goto out; 679 680 } 681 682 if (key) { 683 rep.opt[0] = htonl((TCPOPT_NOP << 24) | 684 (TCPOPT_NOP << 16) | 685 (TCPOPT_MD5SIG << 8) | 686 TCPOLEN_MD5SIG); 687 /* Update length and the length the header thinks exists */ 688 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 689 rep.th.doff = arg.iov[0].iov_len / 4; 690 691 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], 692 key, ip_hdr(skb)->saddr, 693 ip_hdr(skb)->daddr, &rep.th); 694 } 695 #endif 696 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 697 ip_hdr(skb)->saddr, /* XXX */ 698 arg.iov[0].iov_len, IPPROTO_TCP, 0); 699 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 700 arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0; 701 702 /* When socket is gone, all binding information is lost. 703 * routing might fail in this case. No choice here, if we choose to force 704 * input interface, we will misroute in case of asymmetric route. 705 */ 706 if (sk) { 707 arg.bound_dev_if = sk->sk_bound_dev_if; 708 if (sk_fullsock(sk)) 709 trace_tcp_send_reset(sk, skb); 710 } 711 712 BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) != 713 offsetof(struct inet_timewait_sock, tw_bound_dev_if)); 714 715 arg.tos = ip_hdr(skb)->tos; 716 arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL); 717 local_bh_disable(); 718 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), 719 skb, &TCP_SKB_CB(skb)->header.h4.opt, 720 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 721 &arg, arg.iov[0].iov_len); 722 723 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 724 __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); 725 local_bh_enable(); 726 727 #ifdef CONFIG_TCP_MD5SIG 728 out: 729 rcu_read_unlock(); 730 #endif 731 } 732 733 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 734 outside socket context is ugly, certainly. What can I do? 735 */ 736 737 static void tcp_v4_send_ack(const struct sock *sk, 738 struct sk_buff *skb, u32 seq, u32 ack, 739 u32 win, u32 tsval, u32 tsecr, int oif, 740 struct tcp_md5sig_key *key, 741 int reply_flags, u8 tos) 742 { 743 const struct tcphdr *th = tcp_hdr(skb); 744 struct { 745 struct tcphdr th; 746 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2) 747 #ifdef CONFIG_TCP_MD5SIG 748 + (TCPOLEN_MD5SIG_ALIGNED >> 2) 749 #endif 750 ]; 751 } rep; 752 struct net *net = sock_net(sk); 753 struct ip_reply_arg arg; 754 755 memset(&rep.th, 0, sizeof(struct tcphdr)); 756 memset(&arg, 0, sizeof(arg)); 757 758 arg.iov[0].iov_base = (unsigned char *)&rep; 759 arg.iov[0].iov_len = sizeof(rep.th); 760 if (tsecr) { 761 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 762 (TCPOPT_TIMESTAMP << 8) | 763 TCPOLEN_TIMESTAMP); 764 rep.opt[1] = htonl(tsval); 765 rep.opt[2] = htonl(tsecr); 766 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; 767 } 768 769 /* Swap the send and the receive. */ 770 rep.th.dest = th->source; 771 rep.th.source = th->dest; 772 rep.th.doff = arg.iov[0].iov_len / 4; 773 rep.th.seq = htonl(seq); 774 rep.th.ack_seq = htonl(ack); 775 rep.th.ack = 1; 776 rep.th.window = htons(win); 777 778 #ifdef CONFIG_TCP_MD5SIG 779 if (key) { 780 int offset = (tsecr) ? 3 : 0; 781 782 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | 783 (TCPOPT_NOP << 16) | 784 (TCPOPT_MD5SIG << 8) | 785 TCPOLEN_MD5SIG); 786 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 787 rep.th.doff = arg.iov[0].iov_len/4; 788 789 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], 790 key, ip_hdr(skb)->saddr, 791 ip_hdr(skb)->daddr, &rep.th); 792 } 793 #endif 794 arg.flags = reply_flags; 795 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 796 ip_hdr(skb)->saddr, /* XXX */ 797 arg.iov[0].iov_len, IPPROTO_TCP, 0); 798 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 799 if (oif) 800 arg.bound_dev_if = oif; 801 arg.tos = tos; 802 arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL); 803 local_bh_disable(); 804 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), 805 skb, &TCP_SKB_CB(skb)->header.h4.opt, 806 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 807 &arg, arg.iov[0].iov_len); 808 809 __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); 810 local_bh_enable(); 811 } 812 813 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 814 { 815 struct inet_timewait_sock *tw = inet_twsk(sk); 816 struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 817 818 tcp_v4_send_ack(sk, skb, 819 tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 820 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, 821 tcp_time_stamp_raw() + tcptw->tw_ts_offset, 822 tcptw->tw_ts_recent, 823 tw->tw_bound_dev_if, 824 tcp_twsk_md5_key(tcptw), 825 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, 826 tw->tw_tos 827 ); 828 829 inet_twsk_put(tw); 830 } 831 832 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 833 struct request_sock *req) 834 { 835 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV 836 * sk->sk_state == TCP_SYN_RECV -> for Fast Open. 837 */ 838 u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : 839 tcp_sk(sk)->snd_nxt; 840 841 /* RFC 7323 2.3 842 * The window field (SEG.WND) of every outgoing segment, with the 843 * exception of <SYN> segments, MUST be right-shifted by 844 * Rcv.Wind.Shift bits: 845 */ 846 tcp_v4_send_ack(sk, skb, seq, 847 tcp_rsk(req)->rcv_nxt, 848 req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale, 849 tcp_time_stamp_raw() + tcp_rsk(req)->ts_off, 850 req->ts_recent, 851 0, 852 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->saddr, 853 AF_INET), 854 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, 855 ip_hdr(skb)->tos); 856 } 857 858 /* 859 * Send a SYN-ACK after having received a SYN. 860 * This still operates on a request_sock only, not on a big 861 * socket. 862 */ 863 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, 864 struct flowi *fl, 865 struct request_sock *req, 866 struct tcp_fastopen_cookie *foc, 867 enum tcp_synack_type synack_type) 868 { 869 const struct inet_request_sock *ireq = inet_rsk(req); 870 struct flowi4 fl4; 871 int err = -1; 872 struct sk_buff *skb; 873 874 /* First, grab a route. */ 875 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) 876 return -1; 877 878 skb = tcp_make_synack(sk, dst, req, foc, synack_type); 879 880 if (skb) { 881 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); 882 883 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, 884 ireq->ir_rmt_addr, 885 ireq_opt_deref(ireq)); 886 err = net_xmit_eval(err); 887 } 888 889 return err; 890 } 891 892 /* 893 * IPv4 request_sock destructor. 894 */ 895 static void tcp_v4_reqsk_destructor(struct request_sock *req) 896 { 897 kfree(rcu_dereference_protected(inet_rsk(req)->ireq_opt, 1)); 898 } 899 900 #ifdef CONFIG_TCP_MD5SIG 901 /* 902 * RFC2385 MD5 checksumming requires a mapping of 903 * IP address->MD5 Key. 904 * We need to maintain these in the sk structure. 905 */ 906 907 /* Find the Key structure for an address. */ 908 struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk, 909 const union tcp_md5_addr *addr, 910 int family) 911 { 912 const struct tcp_sock *tp = tcp_sk(sk); 913 struct tcp_md5sig_key *key; 914 const struct tcp_md5sig_info *md5sig; 915 __be32 mask; 916 struct tcp_md5sig_key *best_match = NULL; 917 bool match; 918 919 /* caller either holds rcu_read_lock() or socket lock */ 920 md5sig = rcu_dereference_check(tp->md5sig_info, 921 lockdep_sock_is_held(sk)); 922 if (!md5sig) 923 return NULL; 924 925 hlist_for_each_entry_rcu(key, &md5sig->head, node) { 926 if (key->family != family) 927 continue; 928 929 if (family == AF_INET) { 930 mask = inet_make_mask(key->prefixlen); 931 match = (key->addr.a4.s_addr & mask) == 932 (addr->a4.s_addr & mask); 933 #if IS_ENABLED(CONFIG_IPV6) 934 } else if (family == AF_INET6) { 935 match = ipv6_prefix_equal(&key->addr.a6, &addr->a6, 936 key->prefixlen); 937 #endif 938 } else { 939 match = false; 940 } 941 942 if (match && (!best_match || 943 key->prefixlen > best_match->prefixlen)) 944 best_match = key; 945 } 946 return best_match; 947 } 948 EXPORT_SYMBOL(tcp_md5_do_lookup); 949 950 static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk, 951 const union tcp_md5_addr *addr, 952 int family, u8 prefixlen) 953 { 954 const struct tcp_sock *tp = tcp_sk(sk); 955 struct tcp_md5sig_key *key; 956 unsigned int size = sizeof(struct in_addr); 957 const struct tcp_md5sig_info *md5sig; 958 959 /* caller either holds rcu_read_lock() or socket lock */ 960 md5sig = rcu_dereference_check(tp->md5sig_info, 961 lockdep_sock_is_held(sk)); 962 if (!md5sig) 963 return NULL; 964 #if IS_ENABLED(CONFIG_IPV6) 965 if (family == AF_INET6) 966 size = sizeof(struct in6_addr); 967 #endif 968 hlist_for_each_entry_rcu(key, &md5sig->head, node) { 969 if (key->family != family) 970 continue; 971 if (!memcmp(&key->addr, addr, size) && 972 key->prefixlen == prefixlen) 973 return key; 974 } 975 return NULL; 976 } 977 978 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 979 const struct sock *addr_sk) 980 { 981 const union tcp_md5_addr *addr; 982 983 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr; 984 return tcp_md5_do_lookup(sk, addr, AF_INET); 985 } 986 EXPORT_SYMBOL(tcp_v4_md5_lookup); 987 988 /* This can be called on a newly created socket, from other files */ 989 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 990 int family, u8 prefixlen, const u8 *newkey, u8 newkeylen, 991 gfp_t gfp) 992 { 993 /* Add Key to the list */ 994 struct tcp_md5sig_key *key; 995 struct tcp_sock *tp = tcp_sk(sk); 996 struct tcp_md5sig_info *md5sig; 997 998 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen); 999 if (key) { 1000 /* Pre-existing entry - just update that one. */ 1001 memcpy(key->key, newkey, newkeylen); 1002 key->keylen = newkeylen; 1003 return 0; 1004 } 1005 1006 md5sig = rcu_dereference_protected(tp->md5sig_info, 1007 lockdep_sock_is_held(sk)); 1008 if (!md5sig) { 1009 md5sig = kmalloc(sizeof(*md5sig), gfp); 1010 if (!md5sig) 1011 return -ENOMEM; 1012 1013 sk_nocaps_add(sk, NETIF_F_GSO_MASK); 1014 INIT_HLIST_HEAD(&md5sig->head); 1015 rcu_assign_pointer(tp->md5sig_info, md5sig); 1016 } 1017 1018 key = sock_kmalloc(sk, sizeof(*key), gfp); 1019 if (!key) 1020 return -ENOMEM; 1021 if (!tcp_alloc_md5sig_pool()) { 1022 sock_kfree_s(sk, key, sizeof(*key)); 1023 return -ENOMEM; 1024 } 1025 1026 memcpy(key->key, newkey, newkeylen); 1027 key->keylen = newkeylen; 1028 key->family = family; 1029 key->prefixlen = prefixlen; 1030 memcpy(&key->addr, addr, 1031 (family == AF_INET6) ? sizeof(struct in6_addr) : 1032 sizeof(struct in_addr)); 1033 hlist_add_head_rcu(&key->node, &md5sig->head); 1034 return 0; 1035 } 1036 EXPORT_SYMBOL(tcp_md5_do_add); 1037 1038 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family, 1039 u8 prefixlen) 1040 { 1041 struct tcp_md5sig_key *key; 1042 1043 key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen); 1044 if (!key) 1045 return -ENOENT; 1046 hlist_del_rcu(&key->node); 1047 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1048 kfree_rcu(key, rcu); 1049 return 0; 1050 } 1051 EXPORT_SYMBOL(tcp_md5_do_del); 1052 1053 static void tcp_clear_md5_list(struct sock *sk) 1054 { 1055 struct tcp_sock *tp = tcp_sk(sk); 1056 struct tcp_md5sig_key *key; 1057 struct hlist_node *n; 1058 struct tcp_md5sig_info *md5sig; 1059 1060 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 1061 1062 hlist_for_each_entry_safe(key, n, &md5sig->head, node) { 1063 hlist_del_rcu(&key->node); 1064 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1065 kfree_rcu(key, rcu); 1066 } 1067 } 1068 1069 static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, 1070 char __user *optval, int optlen) 1071 { 1072 struct tcp_md5sig cmd; 1073 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; 1074 u8 prefixlen = 32; 1075 1076 if (optlen < sizeof(cmd)) 1077 return -EINVAL; 1078 1079 if (copy_from_user(&cmd, optval, sizeof(cmd))) 1080 return -EFAULT; 1081 1082 if (sin->sin_family != AF_INET) 1083 return -EINVAL; 1084 1085 if (optname == TCP_MD5SIG_EXT && 1086 cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { 1087 prefixlen = cmd.tcpm_prefixlen; 1088 if (prefixlen > 32) 1089 return -EINVAL; 1090 } 1091 1092 if (!cmd.tcpm_keylen) 1093 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, 1094 AF_INET, prefixlen); 1095 1096 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) 1097 return -EINVAL; 1098 1099 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, 1100 AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen, 1101 GFP_KERNEL); 1102 } 1103 1104 static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp, 1105 __be32 daddr, __be32 saddr, 1106 const struct tcphdr *th, int nbytes) 1107 { 1108 struct tcp4_pseudohdr *bp; 1109 struct scatterlist sg; 1110 struct tcphdr *_th; 1111 1112 bp = hp->scratch; 1113 bp->saddr = saddr; 1114 bp->daddr = daddr; 1115 bp->pad = 0; 1116 bp->protocol = IPPROTO_TCP; 1117 bp->len = cpu_to_be16(nbytes); 1118 1119 _th = (struct tcphdr *)(bp + 1); 1120 memcpy(_th, th, sizeof(*th)); 1121 _th->check = 0; 1122 1123 sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th)); 1124 ahash_request_set_crypt(hp->md5_req, &sg, NULL, 1125 sizeof(*bp) + sizeof(*th)); 1126 return crypto_ahash_update(hp->md5_req); 1127 } 1128 1129 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 1130 __be32 daddr, __be32 saddr, const struct tcphdr *th) 1131 { 1132 struct tcp_md5sig_pool *hp; 1133 struct ahash_request *req; 1134 1135 hp = tcp_get_md5sig_pool(); 1136 if (!hp) 1137 goto clear_hash_noput; 1138 req = hp->md5_req; 1139 1140 if (crypto_ahash_init(req)) 1141 goto clear_hash; 1142 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2)) 1143 goto clear_hash; 1144 if (tcp_md5_hash_key(hp, key)) 1145 goto clear_hash; 1146 ahash_request_set_crypt(req, NULL, md5_hash, 0); 1147 if (crypto_ahash_final(req)) 1148 goto clear_hash; 1149 1150 tcp_put_md5sig_pool(); 1151 return 0; 1152 1153 clear_hash: 1154 tcp_put_md5sig_pool(); 1155 clear_hash_noput: 1156 memset(md5_hash, 0, 16); 1157 return 1; 1158 } 1159 1160 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1161 const struct sock *sk, 1162 const struct sk_buff *skb) 1163 { 1164 struct tcp_md5sig_pool *hp; 1165 struct ahash_request *req; 1166 const struct tcphdr *th = tcp_hdr(skb); 1167 __be32 saddr, daddr; 1168 1169 if (sk) { /* valid for establish/request sockets */ 1170 saddr = sk->sk_rcv_saddr; 1171 daddr = sk->sk_daddr; 1172 } else { 1173 const struct iphdr *iph = ip_hdr(skb); 1174 saddr = iph->saddr; 1175 daddr = iph->daddr; 1176 } 1177 1178 hp = tcp_get_md5sig_pool(); 1179 if (!hp) 1180 goto clear_hash_noput; 1181 req = hp->md5_req; 1182 1183 if (crypto_ahash_init(req)) 1184 goto clear_hash; 1185 1186 if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len)) 1187 goto clear_hash; 1188 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) 1189 goto clear_hash; 1190 if (tcp_md5_hash_key(hp, key)) 1191 goto clear_hash; 1192 ahash_request_set_crypt(req, NULL, md5_hash, 0); 1193 if (crypto_ahash_final(req)) 1194 goto clear_hash; 1195 1196 tcp_put_md5sig_pool(); 1197 return 0; 1198 1199 clear_hash: 1200 tcp_put_md5sig_pool(); 1201 clear_hash_noput: 1202 memset(md5_hash, 0, 16); 1203 return 1; 1204 } 1205 EXPORT_SYMBOL(tcp_v4_md5_hash_skb); 1206 1207 #endif 1208 1209 /* Called with rcu_read_lock() */ 1210 static bool tcp_v4_inbound_md5_hash(const struct sock *sk, 1211 const struct sk_buff *skb) 1212 { 1213 #ifdef CONFIG_TCP_MD5SIG 1214 /* 1215 * This gets called for each TCP segment that arrives 1216 * so we want to be efficient. 1217 * We have 3 drop cases: 1218 * o No MD5 hash and one expected. 1219 * o MD5 hash and we're not expecting one. 1220 * o MD5 hash and its wrong. 1221 */ 1222 const __u8 *hash_location = NULL; 1223 struct tcp_md5sig_key *hash_expected; 1224 const struct iphdr *iph = ip_hdr(skb); 1225 const struct tcphdr *th = tcp_hdr(skb); 1226 int genhash; 1227 unsigned char newhash[16]; 1228 1229 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr, 1230 AF_INET); 1231 hash_location = tcp_parse_md5sig_option(th); 1232 1233 /* We've parsed the options - do we have a hash? */ 1234 if (!hash_expected && !hash_location) 1235 return false; 1236 1237 if (hash_expected && !hash_location) { 1238 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); 1239 return true; 1240 } 1241 1242 if (!hash_expected && hash_location) { 1243 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); 1244 return true; 1245 } 1246 1247 /* Okay, so this is hash_expected and hash_location - 1248 * so we need to calculate the checksum. 1249 */ 1250 genhash = tcp_v4_md5_hash_skb(newhash, 1251 hash_expected, 1252 NULL, skb); 1253 1254 if (genhash || memcmp(hash_location, newhash, 16) != 0) { 1255 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE); 1256 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n", 1257 &iph->saddr, ntohs(th->source), 1258 &iph->daddr, ntohs(th->dest), 1259 genhash ? " tcp_v4_calc_md5_hash failed" 1260 : ""); 1261 return true; 1262 } 1263 return false; 1264 #endif 1265 return false; 1266 } 1267 1268 static void tcp_v4_init_req(struct request_sock *req, 1269 const struct sock *sk_listener, 1270 struct sk_buff *skb) 1271 { 1272 struct inet_request_sock *ireq = inet_rsk(req); 1273 struct net *net = sock_net(sk_listener); 1274 1275 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr); 1276 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr); 1277 RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb)); 1278 } 1279 1280 static struct dst_entry *tcp_v4_route_req(const struct sock *sk, 1281 struct flowi *fl, 1282 const struct request_sock *req) 1283 { 1284 return inet_csk_route_req(sk, &fl->u.ip4, req); 1285 } 1286 1287 struct request_sock_ops tcp_request_sock_ops __read_mostly = { 1288 .family = PF_INET, 1289 .obj_size = sizeof(struct tcp_request_sock), 1290 .rtx_syn_ack = tcp_rtx_synack, 1291 .send_ack = tcp_v4_reqsk_send_ack, 1292 .destructor = tcp_v4_reqsk_destructor, 1293 .send_reset = tcp_v4_send_reset, 1294 .syn_ack_timeout = tcp_syn_ack_timeout, 1295 }; 1296 1297 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { 1298 .mss_clamp = TCP_MSS_DEFAULT, 1299 #ifdef CONFIG_TCP_MD5SIG 1300 .req_md5_lookup = tcp_v4_md5_lookup, 1301 .calc_md5_hash = tcp_v4_md5_hash_skb, 1302 #endif 1303 .init_req = tcp_v4_init_req, 1304 #ifdef CONFIG_SYN_COOKIES 1305 .cookie_init_seq = cookie_v4_init_sequence, 1306 #endif 1307 .route_req = tcp_v4_route_req, 1308 .init_seq = tcp_v4_init_seq, 1309 .init_ts_off = tcp_v4_init_ts_off, 1310 .send_synack = tcp_v4_send_synack, 1311 }; 1312 1313 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 1314 { 1315 /* Never answer to SYNs send to broadcast or multicast */ 1316 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) 1317 goto drop; 1318 1319 return tcp_conn_request(&tcp_request_sock_ops, 1320 &tcp_request_sock_ipv4_ops, sk, skb); 1321 1322 drop: 1323 tcp_listendrop(sk); 1324 return 0; 1325 } 1326 EXPORT_SYMBOL(tcp_v4_conn_request); 1327 1328 1329 /* 1330 * The three way handshake has completed - we got a valid synack - 1331 * now create the new socket. 1332 */ 1333 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 1334 struct request_sock *req, 1335 struct dst_entry *dst, 1336 struct request_sock *req_unhash, 1337 bool *own_req) 1338 { 1339 struct inet_request_sock *ireq; 1340 struct inet_sock *newinet; 1341 struct tcp_sock *newtp; 1342 struct sock *newsk; 1343 #ifdef CONFIG_TCP_MD5SIG 1344 struct tcp_md5sig_key *key; 1345 #endif 1346 struct ip_options_rcu *inet_opt; 1347 1348 if (sk_acceptq_is_full(sk)) 1349 goto exit_overflow; 1350 1351 newsk = tcp_create_openreq_child(sk, req, skb); 1352 if (!newsk) 1353 goto exit_nonewsk; 1354 1355 newsk->sk_gso_type = SKB_GSO_TCPV4; 1356 inet_sk_rx_dst_set(newsk, skb); 1357 1358 newtp = tcp_sk(newsk); 1359 newinet = inet_sk(newsk); 1360 ireq = inet_rsk(req); 1361 sk_daddr_set(newsk, ireq->ir_rmt_addr); 1362 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr); 1363 newsk->sk_bound_dev_if = ireq->ir_iif; 1364 newinet->inet_saddr = ireq->ir_loc_addr; 1365 inet_opt = rcu_dereference(ireq->ireq_opt); 1366 RCU_INIT_POINTER(newinet->inet_opt, inet_opt); 1367 newinet->mc_index = inet_iif(skb); 1368 newinet->mc_ttl = ip_hdr(skb)->ttl; 1369 newinet->rcv_tos = ip_hdr(skb)->tos; 1370 inet_csk(newsk)->icsk_ext_hdr_len = 0; 1371 if (inet_opt) 1372 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 1373 newinet->inet_id = newtp->write_seq ^ jiffies; 1374 1375 if (!dst) { 1376 dst = inet_csk_route_child_sock(sk, newsk, req); 1377 if (!dst) 1378 goto put_and_exit; 1379 } else { 1380 /* syncookie case : see end of cookie_v4_check() */ 1381 } 1382 sk_setup_caps(newsk, dst); 1383 1384 tcp_ca_openreq_child(newsk, dst); 1385 1386 tcp_sync_mss(newsk, dst_mtu(dst)); 1387 newtp->advmss = tcp_mss_clamp(tcp_sk(sk), dst_metric_advmss(dst)); 1388 1389 tcp_initialize_rcv_mss(newsk); 1390 1391 #ifdef CONFIG_TCP_MD5SIG 1392 /* Copy over the MD5 key from the original socket */ 1393 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr, 1394 AF_INET); 1395 if (key) { 1396 /* 1397 * We're using one, so create a matching key 1398 * on the newsk structure. If we fail to get 1399 * memory, then we end up not copying the key 1400 * across. Shucks. 1401 */ 1402 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr, 1403 AF_INET, 32, key->key, key->keylen, GFP_ATOMIC); 1404 sk_nocaps_add(newsk, NETIF_F_GSO_MASK); 1405 } 1406 #endif 1407 1408 if (__inet_inherit_port(sk, newsk) < 0) 1409 goto put_and_exit; 1410 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); 1411 if (likely(*own_req)) { 1412 tcp_move_syn(newtp, req); 1413 ireq->ireq_opt = NULL; 1414 } else { 1415 newinet->inet_opt = NULL; 1416 } 1417 return newsk; 1418 1419 exit_overflow: 1420 NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 1421 exit_nonewsk: 1422 dst_release(dst); 1423 exit: 1424 tcp_listendrop(sk); 1425 return NULL; 1426 put_and_exit: 1427 newinet->inet_opt = NULL; 1428 inet_csk_prepare_forced_close(newsk); 1429 tcp_done(newsk); 1430 goto exit; 1431 } 1432 EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 1433 1434 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb) 1435 { 1436 #ifdef CONFIG_SYN_COOKIES 1437 const struct tcphdr *th = tcp_hdr(skb); 1438 1439 if (!th->syn) 1440 sk = cookie_v4_check(sk, skb); 1441 #endif 1442 return sk; 1443 } 1444 1445 /* The socket must have it's spinlock held when we get 1446 * here, unless it is a TCP_LISTEN socket. 1447 * 1448 * We have a potential double-lock case here, so even when 1449 * doing backlog processing we use the BH locking scheme. 1450 * This is because we cannot sleep with the original spinlock 1451 * held. 1452 */ 1453 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1454 { 1455 struct sock *rsk; 1456 1457 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1458 struct dst_entry *dst = sk->sk_rx_dst; 1459 1460 sock_rps_save_rxhash(sk, skb); 1461 sk_mark_napi_id(sk, skb); 1462 if (dst) { 1463 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif || 1464 !dst->ops->check(dst, 0)) { 1465 dst_release(dst); 1466 sk->sk_rx_dst = NULL; 1467 } 1468 } 1469 tcp_rcv_established(sk, skb, tcp_hdr(skb)); 1470 return 0; 1471 } 1472 1473 if (tcp_checksum_complete(skb)) 1474 goto csum_err; 1475 1476 if (sk->sk_state == TCP_LISTEN) { 1477 struct sock *nsk = tcp_v4_cookie_check(sk, skb); 1478 1479 if (!nsk) 1480 goto discard; 1481 if (nsk != sk) { 1482 if (tcp_child_process(sk, nsk, skb)) { 1483 rsk = nsk; 1484 goto reset; 1485 } 1486 return 0; 1487 } 1488 } else 1489 sock_rps_save_rxhash(sk, skb); 1490 1491 if (tcp_rcv_state_process(sk, skb)) { 1492 rsk = sk; 1493 goto reset; 1494 } 1495 return 0; 1496 1497 reset: 1498 tcp_v4_send_reset(rsk, skb); 1499 discard: 1500 kfree_skb(skb); 1501 /* Be careful here. If this function gets more complicated and 1502 * gcc suffers from register pressure on the x86, sk (in %ebx) 1503 * might be destroyed here. This current version compiles correctly, 1504 * but you have been warned. 1505 */ 1506 return 0; 1507 1508 csum_err: 1509 TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); 1510 TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); 1511 goto discard; 1512 } 1513 EXPORT_SYMBOL(tcp_v4_do_rcv); 1514 1515 int tcp_v4_early_demux(struct sk_buff *skb) 1516 { 1517 const struct iphdr *iph; 1518 const struct tcphdr *th; 1519 struct sock *sk; 1520 1521 if (skb->pkt_type != PACKET_HOST) 1522 return 0; 1523 1524 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) 1525 return 0; 1526 1527 iph = ip_hdr(skb); 1528 th = tcp_hdr(skb); 1529 1530 if (th->doff < sizeof(struct tcphdr) / 4) 1531 return 0; 1532 1533 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo, 1534 iph->saddr, th->source, 1535 iph->daddr, ntohs(th->dest), 1536 skb->skb_iif, inet_sdif(skb)); 1537 if (sk) { 1538 skb->sk = sk; 1539 skb->destructor = sock_edemux; 1540 if (sk_fullsock(sk)) { 1541 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); 1542 1543 if (dst) 1544 dst = dst_check(dst, 0); 1545 if (dst && 1546 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif) 1547 skb_dst_set_noref(skb, dst); 1548 } 1549 } 1550 return 0; 1551 } 1552 1553 bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) 1554 { 1555 u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf; 1556 1557 /* Only socket owner can try to collapse/prune rx queues 1558 * to reduce memory overhead, so add a little headroom here. 1559 * Few sockets backlog are possibly concurrently non empty. 1560 */ 1561 limit += 64*1024; 1562 1563 /* In case all data was pulled from skb frags (in __pskb_pull_tail()), 1564 * we can fix skb->truesize to its real value to avoid future drops. 1565 * This is valid because skb is not yet charged to the socket. 1566 * It has been noticed pure SACK packets were sometimes dropped 1567 * (if cooked by drivers without copybreak feature). 1568 */ 1569 skb_condense(skb); 1570 1571 if (unlikely(sk_add_backlog(sk, skb, limit))) { 1572 bh_unlock_sock(sk); 1573 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP); 1574 return true; 1575 } 1576 return false; 1577 } 1578 EXPORT_SYMBOL(tcp_add_backlog); 1579 1580 int tcp_filter(struct sock *sk, struct sk_buff *skb) 1581 { 1582 struct tcphdr *th = (struct tcphdr *)skb->data; 1583 unsigned int eaten = skb->len; 1584 int err; 1585 1586 err = sk_filter_trim_cap(sk, skb, th->doff * 4); 1587 if (!err) { 1588 eaten -= skb->len; 1589 TCP_SKB_CB(skb)->end_seq -= eaten; 1590 } 1591 return err; 1592 } 1593 EXPORT_SYMBOL(tcp_filter); 1594 1595 static void tcp_v4_restore_cb(struct sk_buff *skb) 1596 { 1597 memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4, 1598 sizeof(struct inet_skb_parm)); 1599 } 1600 1601 static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph, 1602 const struct tcphdr *th) 1603 { 1604 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB() 1605 * barrier() makes sure compiler wont play fool^Waliasing games. 1606 */ 1607 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb), 1608 sizeof(struct inet_skb_parm)); 1609 barrier(); 1610 1611 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 1612 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 1613 skb->len - th->doff * 4); 1614 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 1615 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); 1616 TCP_SKB_CB(skb)->tcp_tw_isn = 0; 1617 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); 1618 TCP_SKB_CB(skb)->sacked = 0; 1619 TCP_SKB_CB(skb)->has_rxtstamp = 1620 skb->tstamp || skb_hwtstamps(skb)->hwtstamp; 1621 } 1622 1623 /* 1624 * From tcp_input.c 1625 */ 1626 1627 int tcp_v4_rcv(struct sk_buff *skb) 1628 { 1629 struct net *net = dev_net(skb->dev); 1630 int sdif = inet_sdif(skb); 1631 const struct iphdr *iph; 1632 const struct tcphdr *th; 1633 bool refcounted; 1634 struct sock *sk; 1635 int ret; 1636 1637 if (skb->pkt_type != PACKET_HOST) 1638 goto discard_it; 1639 1640 /* Count it even if it's bad */ 1641 __TCP_INC_STATS(net, TCP_MIB_INSEGS); 1642 1643 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 1644 goto discard_it; 1645 1646 th = (const struct tcphdr *)skb->data; 1647 1648 if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) 1649 goto bad_packet; 1650 if (!pskb_may_pull(skb, th->doff * 4)) 1651 goto discard_it; 1652 1653 /* An explanation is required here, I think. 1654 * Packet length and doff are validated by header prediction, 1655 * provided case of th->doff==0 is eliminated. 1656 * So, we defer the checks. */ 1657 1658 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo)) 1659 goto csum_error; 1660 1661 th = (const struct tcphdr *)skb->data; 1662 iph = ip_hdr(skb); 1663 lookup: 1664 sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source, 1665 th->dest, sdif, &refcounted); 1666 if (!sk) 1667 goto no_tcp_socket; 1668 1669 process: 1670 if (sk->sk_state == TCP_TIME_WAIT) 1671 goto do_time_wait; 1672 1673 if (sk->sk_state == TCP_NEW_SYN_RECV) { 1674 struct request_sock *req = inet_reqsk(sk); 1675 struct sock *nsk; 1676 1677 sk = req->rsk_listener; 1678 if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) { 1679 sk_drops_add(sk, skb); 1680 reqsk_put(req); 1681 goto discard_it; 1682 } 1683 if (unlikely(sk->sk_state != TCP_LISTEN)) { 1684 inet_csk_reqsk_queue_drop_and_put(sk, req); 1685 goto lookup; 1686 } 1687 /* We own a reference on the listener, increase it again 1688 * as we might lose it too soon. 1689 */ 1690 sock_hold(sk); 1691 refcounted = true; 1692 nsk = NULL; 1693 if (!tcp_filter(sk, skb)) { 1694 th = (const struct tcphdr *)skb->data; 1695 iph = ip_hdr(skb); 1696 tcp_v4_fill_cb(skb, iph, th); 1697 nsk = tcp_check_req(sk, skb, req, false); 1698 } 1699 if (!nsk) { 1700 reqsk_put(req); 1701 goto discard_and_relse; 1702 } 1703 if (nsk == sk) { 1704 reqsk_put(req); 1705 tcp_v4_restore_cb(skb); 1706 } else if (tcp_child_process(sk, nsk, skb)) { 1707 tcp_v4_send_reset(nsk, skb); 1708 goto discard_and_relse; 1709 } else { 1710 sock_put(sk); 1711 return 0; 1712 } 1713 } 1714 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { 1715 __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); 1716 goto discard_and_relse; 1717 } 1718 1719 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 1720 goto discard_and_relse; 1721 1722 if (tcp_v4_inbound_md5_hash(sk, skb)) 1723 goto discard_and_relse; 1724 1725 nf_reset(skb); 1726 1727 if (tcp_filter(sk, skb)) 1728 goto discard_and_relse; 1729 th = (const struct tcphdr *)skb->data; 1730 iph = ip_hdr(skb); 1731 tcp_v4_fill_cb(skb, iph, th); 1732 1733 skb->dev = NULL; 1734 1735 if (sk->sk_state == TCP_LISTEN) { 1736 ret = tcp_v4_do_rcv(sk, skb); 1737 goto put_and_return; 1738 } 1739 1740 sk_incoming_cpu_update(sk); 1741 1742 bh_lock_sock_nested(sk); 1743 tcp_segs_in(tcp_sk(sk), skb); 1744 ret = 0; 1745 if (!sock_owned_by_user(sk)) { 1746 ret = tcp_v4_do_rcv(sk, skb); 1747 } else if (tcp_add_backlog(sk, skb)) { 1748 goto discard_and_relse; 1749 } 1750 bh_unlock_sock(sk); 1751 1752 put_and_return: 1753 if (refcounted) 1754 sock_put(sk); 1755 1756 return ret; 1757 1758 no_tcp_socket: 1759 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 1760 goto discard_it; 1761 1762 tcp_v4_fill_cb(skb, iph, th); 1763 1764 if (tcp_checksum_complete(skb)) { 1765 csum_error: 1766 __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS); 1767 bad_packet: 1768 __TCP_INC_STATS(net, TCP_MIB_INERRS); 1769 } else { 1770 tcp_v4_send_reset(NULL, skb); 1771 } 1772 1773 discard_it: 1774 /* Discard frame. */ 1775 kfree_skb(skb); 1776 return 0; 1777 1778 discard_and_relse: 1779 sk_drops_add(sk, skb); 1780 if (refcounted) 1781 sock_put(sk); 1782 goto discard_it; 1783 1784 do_time_wait: 1785 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 1786 inet_twsk_put(inet_twsk(sk)); 1787 goto discard_it; 1788 } 1789 1790 tcp_v4_fill_cb(skb, iph, th); 1791 1792 if (tcp_checksum_complete(skb)) { 1793 inet_twsk_put(inet_twsk(sk)); 1794 goto csum_error; 1795 } 1796 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { 1797 case TCP_TW_SYN: { 1798 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev), 1799 &tcp_hashinfo, skb, 1800 __tcp_hdrlen(th), 1801 iph->saddr, th->source, 1802 iph->daddr, th->dest, 1803 inet_iif(skb), 1804 sdif); 1805 if (sk2) { 1806 inet_twsk_deschedule_put(inet_twsk(sk)); 1807 sk = sk2; 1808 tcp_v4_restore_cb(skb); 1809 refcounted = false; 1810 goto process; 1811 } 1812 } 1813 /* to ACK */ 1814 /* fall through */ 1815 case TCP_TW_ACK: 1816 tcp_v4_timewait_ack(sk, skb); 1817 break; 1818 case TCP_TW_RST: 1819 tcp_v4_send_reset(sk, skb); 1820 inet_twsk_deschedule_put(inet_twsk(sk)); 1821 goto discard_it; 1822 case TCP_TW_SUCCESS:; 1823 } 1824 goto discard_it; 1825 } 1826 1827 static struct timewait_sock_ops tcp_timewait_sock_ops = { 1828 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 1829 .twsk_unique = tcp_twsk_unique, 1830 .twsk_destructor= tcp_twsk_destructor, 1831 }; 1832 1833 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 1834 { 1835 struct dst_entry *dst = skb_dst(skb); 1836 1837 if (dst && dst_hold_safe(dst)) { 1838 sk->sk_rx_dst = dst; 1839 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; 1840 } 1841 } 1842 EXPORT_SYMBOL(inet_sk_rx_dst_set); 1843 1844 const struct inet_connection_sock_af_ops ipv4_specific = { 1845 .queue_xmit = ip_queue_xmit, 1846 .send_check = tcp_v4_send_check, 1847 .rebuild_header = inet_sk_rebuild_header, 1848 .sk_rx_dst_set = inet_sk_rx_dst_set, 1849 .conn_request = tcp_v4_conn_request, 1850 .syn_recv_sock = tcp_v4_syn_recv_sock, 1851 .net_header_len = sizeof(struct iphdr), 1852 .setsockopt = ip_setsockopt, 1853 .getsockopt = ip_getsockopt, 1854 .addr2sockaddr = inet_csk_addr2sockaddr, 1855 .sockaddr_len = sizeof(struct sockaddr_in), 1856 #ifdef CONFIG_COMPAT 1857 .compat_setsockopt = compat_ip_setsockopt, 1858 .compat_getsockopt = compat_ip_getsockopt, 1859 #endif 1860 .mtu_reduced = tcp_v4_mtu_reduced, 1861 }; 1862 EXPORT_SYMBOL(ipv4_specific); 1863 1864 #ifdef CONFIG_TCP_MD5SIG 1865 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { 1866 .md5_lookup = tcp_v4_md5_lookup, 1867 .calc_md5_hash = tcp_v4_md5_hash_skb, 1868 .md5_parse = tcp_v4_parse_md5_keys, 1869 }; 1870 #endif 1871 1872 /* NOTE: A lot of things set to zero explicitly by call to 1873 * sk_alloc() so need not be done here. 1874 */ 1875 static int tcp_v4_init_sock(struct sock *sk) 1876 { 1877 struct inet_connection_sock *icsk = inet_csk(sk); 1878 1879 tcp_init_sock(sk); 1880 1881 icsk->icsk_af_ops = &ipv4_specific; 1882 1883 #ifdef CONFIG_TCP_MD5SIG 1884 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific; 1885 #endif 1886 1887 return 0; 1888 } 1889 1890 void tcp_v4_destroy_sock(struct sock *sk) 1891 { 1892 struct tcp_sock *tp = tcp_sk(sk); 1893 1894 trace_tcp_destroy_sock(sk); 1895 1896 tcp_clear_xmit_timers(sk); 1897 1898 tcp_cleanup_congestion_control(sk); 1899 1900 tcp_cleanup_ulp(sk); 1901 1902 /* Cleanup up the write buffer. */ 1903 tcp_write_queue_purge(sk); 1904 1905 /* Check if we want to disable active TFO */ 1906 tcp_fastopen_active_disable_ofo_check(sk); 1907 1908 /* Cleans up our, hopefully empty, out_of_order_queue. */ 1909 skb_rbtree_purge(&tp->out_of_order_queue); 1910 1911 #ifdef CONFIG_TCP_MD5SIG 1912 /* Clean up the MD5 key list, if any */ 1913 if (tp->md5sig_info) { 1914 tcp_clear_md5_list(sk); 1915 kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu); 1916 tp->md5sig_info = NULL; 1917 } 1918 #endif 1919 1920 /* Clean up a referenced TCP bind bucket. */ 1921 if (inet_csk(sk)->icsk_bind_hash) 1922 inet_put_port(sk); 1923 1924 BUG_ON(tp->fastopen_rsk); 1925 1926 /* If socket is aborted during connect operation */ 1927 tcp_free_fastopen_req(tp); 1928 tcp_fastopen_destroy_cipher(sk); 1929 tcp_saved_syn_free(tp); 1930 1931 sk_sockets_allocated_dec(sk); 1932 } 1933 EXPORT_SYMBOL(tcp_v4_destroy_sock); 1934 1935 #ifdef CONFIG_PROC_FS 1936 /* Proc filesystem TCP sock list dumping. */ 1937 1938 /* 1939 * Get next listener socket follow cur. If cur is NULL, get first socket 1940 * starting from bucket given in st->bucket; when st->bucket is zero the 1941 * very first socket in the hash table is returned. 1942 */ 1943 static void *listening_get_next(struct seq_file *seq, void *cur) 1944 { 1945 struct tcp_iter_state *st = seq->private; 1946 struct net *net = seq_file_net(seq); 1947 struct inet_listen_hashbucket *ilb; 1948 struct sock *sk = cur; 1949 1950 if (!sk) { 1951 get_head: 1952 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1953 spin_lock(&ilb->lock); 1954 sk = sk_head(&ilb->head); 1955 st->offset = 0; 1956 goto get_sk; 1957 } 1958 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1959 ++st->num; 1960 ++st->offset; 1961 1962 sk = sk_next(sk); 1963 get_sk: 1964 sk_for_each_from(sk) { 1965 if (!net_eq(sock_net(sk), net)) 1966 continue; 1967 if (sk->sk_family == st->family) 1968 return sk; 1969 } 1970 spin_unlock(&ilb->lock); 1971 st->offset = 0; 1972 if (++st->bucket < INET_LHTABLE_SIZE) 1973 goto get_head; 1974 return NULL; 1975 } 1976 1977 static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 1978 { 1979 struct tcp_iter_state *st = seq->private; 1980 void *rc; 1981 1982 st->bucket = 0; 1983 st->offset = 0; 1984 rc = listening_get_next(seq, NULL); 1985 1986 while (rc && *pos) { 1987 rc = listening_get_next(seq, rc); 1988 --*pos; 1989 } 1990 return rc; 1991 } 1992 1993 static inline bool empty_bucket(const struct tcp_iter_state *st) 1994 { 1995 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain); 1996 } 1997 1998 /* 1999 * Get first established socket starting from bucket given in st->bucket. 2000 * If st->bucket is zero, the very first socket in the hash is returned. 2001 */ 2002 static void *established_get_first(struct seq_file *seq) 2003 { 2004 struct tcp_iter_state *st = seq->private; 2005 struct net *net = seq_file_net(seq); 2006 void *rc = NULL; 2007 2008 st->offset = 0; 2009 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) { 2010 struct sock *sk; 2011 struct hlist_nulls_node *node; 2012 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket); 2013 2014 /* Lockless fast path for the common case of empty buckets */ 2015 if (empty_bucket(st)) 2016 continue; 2017 2018 spin_lock_bh(lock); 2019 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { 2020 if (sk->sk_family != st->family || 2021 !net_eq(sock_net(sk), net)) { 2022 continue; 2023 } 2024 rc = sk; 2025 goto out; 2026 } 2027 spin_unlock_bh(lock); 2028 } 2029 out: 2030 return rc; 2031 } 2032 2033 static void *established_get_next(struct seq_file *seq, void *cur) 2034 { 2035 struct sock *sk = cur; 2036 struct hlist_nulls_node *node; 2037 struct tcp_iter_state *st = seq->private; 2038 struct net *net = seq_file_net(seq); 2039 2040 ++st->num; 2041 ++st->offset; 2042 2043 sk = sk_nulls_next(sk); 2044 2045 sk_nulls_for_each_from(sk, node) { 2046 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) 2047 return sk; 2048 } 2049 2050 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); 2051 ++st->bucket; 2052 return established_get_first(seq); 2053 } 2054 2055 static void *established_get_idx(struct seq_file *seq, loff_t pos) 2056 { 2057 struct tcp_iter_state *st = seq->private; 2058 void *rc; 2059 2060 st->bucket = 0; 2061 rc = established_get_first(seq); 2062 2063 while (rc && pos) { 2064 rc = established_get_next(seq, rc); 2065 --pos; 2066 } 2067 return rc; 2068 } 2069 2070 static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 2071 { 2072 void *rc; 2073 struct tcp_iter_state *st = seq->private; 2074 2075 st->state = TCP_SEQ_STATE_LISTENING; 2076 rc = listening_get_idx(seq, &pos); 2077 2078 if (!rc) { 2079 st->state = TCP_SEQ_STATE_ESTABLISHED; 2080 rc = established_get_idx(seq, pos); 2081 } 2082 2083 return rc; 2084 } 2085 2086 static void *tcp_seek_last_pos(struct seq_file *seq) 2087 { 2088 struct tcp_iter_state *st = seq->private; 2089 int offset = st->offset; 2090 int orig_num = st->num; 2091 void *rc = NULL; 2092 2093 switch (st->state) { 2094 case TCP_SEQ_STATE_LISTENING: 2095 if (st->bucket >= INET_LHTABLE_SIZE) 2096 break; 2097 st->state = TCP_SEQ_STATE_LISTENING; 2098 rc = listening_get_next(seq, NULL); 2099 while (offset-- && rc) 2100 rc = listening_get_next(seq, rc); 2101 if (rc) 2102 break; 2103 st->bucket = 0; 2104 st->state = TCP_SEQ_STATE_ESTABLISHED; 2105 /* Fallthrough */ 2106 case TCP_SEQ_STATE_ESTABLISHED: 2107 if (st->bucket > tcp_hashinfo.ehash_mask) 2108 break; 2109 rc = established_get_first(seq); 2110 while (offset-- && rc) 2111 rc = established_get_next(seq, rc); 2112 } 2113 2114 st->num = orig_num; 2115 2116 return rc; 2117 } 2118 2119 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 2120 { 2121 struct tcp_iter_state *st = seq->private; 2122 void *rc; 2123 2124 if (*pos && *pos == st->last_pos) { 2125 rc = tcp_seek_last_pos(seq); 2126 if (rc) 2127 goto out; 2128 } 2129 2130 st->state = TCP_SEQ_STATE_LISTENING; 2131 st->num = 0; 2132 st->bucket = 0; 2133 st->offset = 0; 2134 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 2135 2136 out: 2137 st->last_pos = *pos; 2138 return rc; 2139 } 2140 2141 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2142 { 2143 struct tcp_iter_state *st = seq->private; 2144 void *rc = NULL; 2145 2146 if (v == SEQ_START_TOKEN) { 2147 rc = tcp_get_idx(seq, 0); 2148 goto out; 2149 } 2150 2151 switch (st->state) { 2152 case TCP_SEQ_STATE_LISTENING: 2153 rc = listening_get_next(seq, v); 2154 if (!rc) { 2155 st->state = TCP_SEQ_STATE_ESTABLISHED; 2156 st->bucket = 0; 2157 st->offset = 0; 2158 rc = established_get_first(seq); 2159 } 2160 break; 2161 case TCP_SEQ_STATE_ESTABLISHED: 2162 rc = established_get_next(seq, v); 2163 break; 2164 } 2165 out: 2166 ++*pos; 2167 st->last_pos = *pos; 2168 return rc; 2169 } 2170 2171 static void tcp_seq_stop(struct seq_file *seq, void *v) 2172 { 2173 struct tcp_iter_state *st = seq->private; 2174 2175 switch (st->state) { 2176 case TCP_SEQ_STATE_LISTENING: 2177 if (v != SEQ_START_TOKEN) 2178 spin_unlock(&tcp_hashinfo.listening_hash[st->bucket].lock); 2179 break; 2180 case TCP_SEQ_STATE_ESTABLISHED: 2181 if (v) 2182 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); 2183 break; 2184 } 2185 } 2186 2187 int tcp_seq_open(struct inode *inode, struct file *file) 2188 { 2189 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode); 2190 struct tcp_iter_state *s; 2191 int err; 2192 2193 err = seq_open_net(inode, file, &afinfo->seq_ops, 2194 sizeof(struct tcp_iter_state)); 2195 if (err < 0) 2196 return err; 2197 2198 s = ((struct seq_file *)file->private_data)->private; 2199 s->family = afinfo->family; 2200 s->last_pos = 0; 2201 return 0; 2202 } 2203 EXPORT_SYMBOL(tcp_seq_open); 2204 2205 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo) 2206 { 2207 int rc = 0; 2208 struct proc_dir_entry *p; 2209 2210 afinfo->seq_ops.start = tcp_seq_start; 2211 afinfo->seq_ops.next = tcp_seq_next; 2212 afinfo->seq_ops.stop = tcp_seq_stop; 2213 2214 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net, 2215 afinfo->seq_fops, afinfo); 2216 if (!p) 2217 rc = -ENOMEM; 2218 return rc; 2219 } 2220 EXPORT_SYMBOL(tcp_proc_register); 2221 2222 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo) 2223 { 2224 remove_proc_entry(afinfo->name, net->proc_net); 2225 } 2226 EXPORT_SYMBOL(tcp_proc_unregister); 2227 2228 static void get_openreq4(const struct request_sock *req, 2229 struct seq_file *f, int i) 2230 { 2231 const struct inet_request_sock *ireq = inet_rsk(req); 2232 long delta = req->rsk_timer.expires - jiffies; 2233 2234 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2235 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK", 2236 i, 2237 ireq->ir_loc_addr, 2238 ireq->ir_num, 2239 ireq->ir_rmt_addr, 2240 ntohs(ireq->ir_rmt_port), 2241 TCP_SYN_RECV, 2242 0, 0, /* could print option size, but that is af dependent. */ 2243 1, /* timers active (only the expire timer) */ 2244 jiffies_delta_to_clock_t(delta), 2245 req->num_timeout, 2246 from_kuid_munged(seq_user_ns(f), 2247 sock_i_uid(req->rsk_listener)), 2248 0, /* non standard timer */ 2249 0, /* open_requests have no inode */ 2250 0, 2251 req); 2252 } 2253 2254 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) 2255 { 2256 int timer_active; 2257 unsigned long timer_expires; 2258 const struct tcp_sock *tp = tcp_sk(sk); 2259 const struct inet_connection_sock *icsk = inet_csk(sk); 2260 const struct inet_sock *inet = inet_sk(sk); 2261 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; 2262 __be32 dest = inet->inet_daddr; 2263 __be32 src = inet->inet_rcv_saddr; 2264 __u16 destp = ntohs(inet->inet_dport); 2265 __u16 srcp = ntohs(inet->inet_sport); 2266 int rx_queue; 2267 int state; 2268 2269 if (icsk->icsk_pending == ICSK_TIME_RETRANS || 2270 icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT || 2271 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { 2272 timer_active = 1; 2273 timer_expires = icsk->icsk_timeout; 2274 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 2275 timer_active = 4; 2276 timer_expires = icsk->icsk_timeout; 2277 } else if (timer_pending(&sk->sk_timer)) { 2278 timer_active = 2; 2279 timer_expires = sk->sk_timer.expires; 2280 } else { 2281 timer_active = 0; 2282 timer_expires = jiffies; 2283 } 2284 2285 state = inet_sk_state_load(sk); 2286 if (state == TCP_LISTEN) 2287 rx_queue = sk->sk_ack_backlog; 2288 else 2289 /* Because we don't lock the socket, 2290 * we might find a transient negative value. 2291 */ 2292 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0); 2293 2294 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 2295 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d", 2296 i, src, srcp, dest, destp, state, 2297 tp->write_seq - tp->snd_una, 2298 rx_queue, 2299 timer_active, 2300 jiffies_delta_to_clock_t(timer_expires - jiffies), 2301 icsk->icsk_retransmits, 2302 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)), 2303 icsk->icsk_probes_out, 2304 sock_i_ino(sk), 2305 refcount_read(&sk->sk_refcnt), sk, 2306 jiffies_to_clock_t(icsk->icsk_rto), 2307 jiffies_to_clock_t(icsk->icsk_ack.ato), 2308 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, 2309 tp->snd_cwnd, 2310 state == TCP_LISTEN ? 2311 fastopenq->max_qlen : 2312 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); 2313 } 2314 2315 static void get_timewait4_sock(const struct inet_timewait_sock *tw, 2316 struct seq_file *f, int i) 2317 { 2318 long delta = tw->tw_timer.expires - jiffies; 2319 __be32 dest, src; 2320 __u16 destp, srcp; 2321 2322 dest = tw->tw_daddr; 2323 src = tw->tw_rcv_saddr; 2324 destp = ntohs(tw->tw_dport); 2325 srcp = ntohs(tw->tw_sport); 2326 2327 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2328 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK", 2329 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 2330 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, 2331 refcount_read(&tw->tw_refcnt), tw); 2332 } 2333 2334 #define TMPSZ 150 2335 2336 static int tcp4_seq_show(struct seq_file *seq, void *v) 2337 { 2338 struct tcp_iter_state *st; 2339 struct sock *sk = v; 2340 2341 seq_setwidth(seq, TMPSZ - 1); 2342 if (v == SEQ_START_TOKEN) { 2343 seq_puts(seq, " sl local_address rem_address st tx_queue " 2344 "rx_queue tr tm->when retrnsmt uid timeout " 2345 "inode"); 2346 goto out; 2347 } 2348 st = seq->private; 2349 2350 if (sk->sk_state == TCP_TIME_WAIT) 2351 get_timewait4_sock(v, seq, st->num); 2352 else if (sk->sk_state == TCP_NEW_SYN_RECV) 2353 get_openreq4(v, seq, st->num); 2354 else 2355 get_tcp4_sock(v, seq, st->num); 2356 out: 2357 seq_pad(seq, '\n'); 2358 return 0; 2359 } 2360 2361 static const struct file_operations tcp_afinfo_seq_fops = { 2362 .open = tcp_seq_open, 2363 .read = seq_read, 2364 .llseek = seq_lseek, 2365 .release = seq_release_net 2366 }; 2367 2368 static struct tcp_seq_afinfo tcp4_seq_afinfo = { 2369 .name = "tcp", 2370 .family = AF_INET, 2371 .seq_fops = &tcp_afinfo_seq_fops, 2372 .seq_ops = { 2373 .show = tcp4_seq_show, 2374 }, 2375 }; 2376 2377 static int __net_init tcp4_proc_init_net(struct net *net) 2378 { 2379 return tcp_proc_register(net, &tcp4_seq_afinfo); 2380 } 2381 2382 static void __net_exit tcp4_proc_exit_net(struct net *net) 2383 { 2384 tcp_proc_unregister(net, &tcp4_seq_afinfo); 2385 } 2386 2387 static struct pernet_operations tcp4_net_ops = { 2388 .init = tcp4_proc_init_net, 2389 .exit = tcp4_proc_exit_net, 2390 }; 2391 2392 int __init tcp4_proc_init(void) 2393 { 2394 return register_pernet_subsys(&tcp4_net_ops); 2395 } 2396 2397 void tcp4_proc_exit(void) 2398 { 2399 unregister_pernet_subsys(&tcp4_net_ops); 2400 } 2401 #endif /* CONFIG_PROC_FS */ 2402 2403 struct proto tcp_prot = { 2404 .name = "TCP", 2405 .owner = THIS_MODULE, 2406 .close = tcp_close, 2407 .connect = tcp_v4_connect, 2408 .disconnect = tcp_disconnect, 2409 .accept = inet_csk_accept, 2410 .ioctl = tcp_ioctl, 2411 .init = tcp_v4_init_sock, 2412 .destroy = tcp_v4_destroy_sock, 2413 .shutdown = tcp_shutdown, 2414 .setsockopt = tcp_setsockopt, 2415 .getsockopt = tcp_getsockopt, 2416 .keepalive = tcp_set_keepalive, 2417 .recvmsg = tcp_recvmsg, 2418 .sendmsg = tcp_sendmsg, 2419 .sendpage = tcp_sendpage, 2420 .backlog_rcv = tcp_v4_do_rcv, 2421 .release_cb = tcp_release_cb, 2422 .hash = inet_hash, 2423 .unhash = inet_unhash, 2424 .get_port = inet_csk_get_port, 2425 .enter_memory_pressure = tcp_enter_memory_pressure, 2426 .leave_memory_pressure = tcp_leave_memory_pressure, 2427 .stream_memory_free = tcp_stream_memory_free, 2428 .sockets_allocated = &tcp_sockets_allocated, 2429 .orphan_count = &tcp_orphan_count, 2430 .memory_allocated = &tcp_memory_allocated, 2431 .memory_pressure = &tcp_memory_pressure, 2432 .sysctl_mem = sysctl_tcp_mem, 2433 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 2434 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 2435 .max_header = MAX_TCP_HEADER, 2436 .obj_size = sizeof(struct tcp_sock), 2437 .slab_flags = SLAB_TYPESAFE_BY_RCU, 2438 .twsk_prot = &tcp_timewait_sock_ops, 2439 .rsk_prot = &tcp_request_sock_ops, 2440 .h.hashinfo = &tcp_hashinfo, 2441 .no_autobind = true, 2442 #ifdef CONFIG_COMPAT 2443 .compat_setsockopt = compat_tcp_setsockopt, 2444 .compat_getsockopt = compat_tcp_getsockopt, 2445 #endif 2446 .diag_destroy = tcp_abort, 2447 }; 2448 EXPORT_SYMBOL(tcp_prot); 2449 2450 static void __net_exit tcp_sk_exit(struct net *net) 2451 { 2452 int cpu; 2453 2454 module_put(net->ipv4.tcp_congestion_control->owner); 2455 2456 for_each_possible_cpu(cpu) 2457 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu)); 2458 free_percpu(net->ipv4.tcp_sk); 2459 } 2460 2461 static int __net_init tcp_sk_init(struct net *net) 2462 { 2463 int res, cpu, cnt; 2464 2465 net->ipv4.tcp_sk = alloc_percpu(struct sock *); 2466 if (!net->ipv4.tcp_sk) 2467 return -ENOMEM; 2468 2469 for_each_possible_cpu(cpu) { 2470 struct sock *sk; 2471 2472 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW, 2473 IPPROTO_TCP, net); 2474 if (res) 2475 goto fail; 2476 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 2477 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk; 2478 } 2479 2480 net->ipv4.sysctl_tcp_ecn = 2; 2481 net->ipv4.sysctl_tcp_ecn_fallback = 1; 2482 2483 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS; 2484 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD; 2485 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL; 2486 2487 net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME; 2488 net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES; 2489 net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL; 2490 2491 net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES; 2492 net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES; 2493 net->ipv4.sysctl_tcp_syncookies = 1; 2494 net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH; 2495 net->ipv4.sysctl_tcp_retries1 = TCP_RETR1; 2496 net->ipv4.sysctl_tcp_retries2 = TCP_RETR2; 2497 net->ipv4.sysctl_tcp_orphan_retries = 0; 2498 net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT; 2499 net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX; 2500 net->ipv4.sysctl_tcp_tw_reuse = 0; 2501 2502 cnt = tcp_hashinfo.ehash_mask + 1; 2503 net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (cnt + 1) / 2; 2504 net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo; 2505 2506 net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 256); 2507 net->ipv4.sysctl_tcp_sack = 1; 2508 net->ipv4.sysctl_tcp_window_scaling = 1; 2509 net->ipv4.sysctl_tcp_timestamps = 1; 2510 net->ipv4.sysctl_tcp_early_retrans = 3; 2511 net->ipv4.sysctl_tcp_recovery = TCP_RACK_LOSS_DETECTION; 2512 net->ipv4.sysctl_tcp_slow_start_after_idle = 1; /* By default, RFC2861 behavior. */ 2513 net->ipv4.sysctl_tcp_retrans_collapse = 1; 2514 net->ipv4.sysctl_tcp_max_reordering = 300; 2515 net->ipv4.sysctl_tcp_dsack = 1; 2516 net->ipv4.sysctl_tcp_app_win = 31; 2517 net->ipv4.sysctl_tcp_adv_win_scale = 1; 2518 net->ipv4.sysctl_tcp_frto = 2; 2519 net->ipv4.sysctl_tcp_moderate_rcvbuf = 1; 2520 /* This limits the percentage of the congestion window which we 2521 * will allow a single TSO frame to consume. Building TSO frames 2522 * which are too large can cause TCP streams to be bursty. 2523 */ 2524 net->ipv4.sysctl_tcp_tso_win_divisor = 3; 2525 /* Default TSQ limit of four TSO segments */ 2526 net->ipv4.sysctl_tcp_limit_output_bytes = 262144; 2527 /* rfc5961 challenge ack rate limiting */ 2528 net->ipv4.sysctl_tcp_challenge_ack_limit = 1000; 2529 net->ipv4.sysctl_tcp_min_tso_segs = 2; 2530 net->ipv4.sysctl_tcp_min_rtt_wlen = 300; 2531 net->ipv4.sysctl_tcp_autocorking = 1; 2532 net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2; 2533 net->ipv4.sysctl_tcp_pacing_ss_ratio = 200; 2534 net->ipv4.sysctl_tcp_pacing_ca_ratio = 120; 2535 if (net != &init_net) { 2536 memcpy(net->ipv4.sysctl_tcp_rmem, 2537 init_net.ipv4.sysctl_tcp_rmem, 2538 sizeof(init_net.ipv4.sysctl_tcp_rmem)); 2539 memcpy(net->ipv4.sysctl_tcp_wmem, 2540 init_net.ipv4.sysctl_tcp_wmem, 2541 sizeof(init_net.ipv4.sysctl_tcp_wmem)); 2542 } 2543 net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE; 2544 spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock); 2545 net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60; 2546 atomic_set(&net->ipv4.tfo_active_disable_times, 0); 2547 2548 /* Reno is always built in */ 2549 if (!net_eq(net, &init_net) && 2550 try_module_get(init_net.ipv4.tcp_congestion_control->owner)) 2551 net->ipv4.tcp_congestion_control = init_net.ipv4.tcp_congestion_control; 2552 else 2553 net->ipv4.tcp_congestion_control = &tcp_reno; 2554 2555 return 0; 2556 fail: 2557 tcp_sk_exit(net); 2558 2559 return res; 2560 } 2561 2562 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) 2563 { 2564 struct net *net; 2565 2566 inet_twsk_purge(&tcp_hashinfo, AF_INET); 2567 2568 list_for_each_entry(net, net_exit_list, exit_list) 2569 tcp_fastopen_ctx_destroy(net); 2570 } 2571 2572 static struct pernet_operations __net_initdata tcp_sk_ops = { 2573 .init = tcp_sk_init, 2574 .exit = tcp_sk_exit, 2575 .exit_batch = tcp_sk_exit_batch, 2576 }; 2577 2578 void __init tcp_v4_init(void) 2579 { 2580 if (register_pernet_subsys(&tcp_sk_ops)) 2581 panic("Failed to create the TCP control socket.\n"); 2582 } 2583