tcp_ipv4.c revision 9ea88a153001ffeb3d8810917e8eea62ca9b6f25
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/netdma.h> 76#include <net/secure_seq.h> 77#include <net/tcp_memcontrol.h> 78#include <net/busy_poll.h> 79 80#include <linux/inet.h> 81#include <linux/ipv6.h> 82#include <linux/stddef.h> 83#include <linux/proc_fs.h> 84#include <linux/seq_file.h> 85 86#include <linux/crypto.h> 87#include <linux/scatterlist.h> 88 89int sysctl_tcp_tw_reuse __read_mostly; 90int sysctl_tcp_low_latency __read_mostly; 91EXPORT_SYMBOL(sysctl_tcp_low_latency); 92 93 94#ifdef CONFIG_TCP_MD5SIG 95static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 96 __be32 daddr, __be32 saddr, const struct tcphdr *th); 97#endif 98 99struct inet_hashinfo tcp_hashinfo; 100EXPORT_SYMBOL(tcp_hashinfo); 101 102static __u32 tcp_v4_init_sequence(const struct sk_buff *skb) 103{ 104 return secure_tcp_sequence_number(ip_hdr(skb)->daddr, 105 ip_hdr(skb)->saddr, 106 tcp_hdr(skb)->dest, 107 tcp_hdr(skb)->source); 108} 109 110int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 111{ 112 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); 113 struct tcp_sock *tp = tcp_sk(sk); 114 115 /* With PAWS, it is safe from the viewpoint 116 of data integrity. Even without PAWS it is safe provided sequence 117 spaces do not overlap i.e. at data rates <= 80Mbit/sec. 118 119 Actually, the idea is close to VJ's one, only timestamp cache is 120 held not per host, but per port pair and TW bucket is used as state 121 holder. 122 123 If TW bucket has been already destroyed we fall back to VJ's scheme 124 and use initial timestamp retrieved from peer table. 125 */ 126 if (tcptw->tw_ts_recent_stamp && 127 (twp == NULL || (sysctl_tcp_tw_reuse && 128 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) { 129 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; 130 if (tp->write_seq == 0) 131 tp->write_seq = 1; 132 tp->rx_opt.ts_recent = tcptw->tw_ts_recent; 133 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; 134 sock_hold(sktw); 135 return 1; 136 } 137 138 return 0; 139} 140EXPORT_SYMBOL_GPL(tcp_twsk_unique); 141 142/* This will initiate an outgoing connection. */ 143int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 144{ 145 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; 146 struct inet_sock *inet = inet_sk(sk); 147 struct tcp_sock *tp = tcp_sk(sk); 148 __be16 orig_sport, orig_dport; 149 __be32 daddr, nexthop; 150 struct flowi4 *fl4; 151 struct rtable *rt; 152 int err; 153 struct ip_options_rcu *inet_opt; 154 155 if (addr_len < sizeof(struct sockaddr_in)) 156 return -EINVAL; 157 158 if (usin->sin_family != AF_INET) 159 return -EAFNOSUPPORT; 160 161 nexthop = daddr = usin->sin_addr.s_addr; 162 inet_opt = rcu_dereference_protected(inet->inet_opt, 163 sock_owned_by_user(sk)); 164 if (inet_opt && inet_opt->opt.srr) { 165 if (!daddr) 166 return -EINVAL; 167 nexthop = inet_opt->opt.faddr; 168 } 169 170 orig_sport = inet->inet_sport; 171 orig_dport = usin->sin_port; 172 fl4 = &inet->cork.fl.u.ip4; 173 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, 174 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, 175 IPPROTO_TCP, 176 orig_sport, orig_dport, sk); 177 if (IS_ERR(rt)) { 178 err = PTR_ERR(rt); 179 if (err == -ENETUNREACH) 180 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 181 return err; 182 } 183 184 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 185 ip_rt_put(rt); 186 return -ENETUNREACH; 187 } 188 189 if (!inet_opt || !inet_opt->opt.srr) 190 daddr = fl4->daddr; 191 192 if (!inet->inet_saddr) 193 inet->inet_saddr = fl4->saddr; 194 inet->inet_rcv_saddr = inet->inet_saddr; 195 196 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) { 197 /* Reset inherited state */ 198 tp->rx_opt.ts_recent = 0; 199 tp->rx_opt.ts_recent_stamp = 0; 200 if (likely(!tp->repair)) 201 tp->write_seq = 0; 202 } 203 204 if (tcp_death_row.sysctl_tw_recycle && 205 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) 206 tcp_fetch_timewait_stamp(sk, &rt->dst); 207 208 inet->inet_dport = usin->sin_port; 209 inet->inet_daddr = daddr; 210 211 inet_set_txhash(sk); 212 213 inet_csk(sk)->icsk_ext_hdr_len = 0; 214 if (inet_opt) 215 inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 216 217 tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; 218 219 /* Socket identity is still unknown (sport may be zero). 220 * However we set state to SYN-SENT and not releasing socket 221 * lock select source port, enter ourselves into the hash tables and 222 * complete initialization after this. 223 */ 224 tcp_set_state(sk, TCP_SYN_SENT); 225 err = inet_hash_connect(&tcp_death_row, sk); 226 if (err) 227 goto failure; 228 229 rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, 230 inet->inet_sport, inet->inet_dport, sk); 231 if (IS_ERR(rt)) { 232 err = PTR_ERR(rt); 233 rt = NULL; 234 goto failure; 235 } 236 /* OK, now commit destination to socket. */ 237 sk->sk_gso_type = SKB_GSO_TCPV4; 238 sk_setup_caps(sk, &rt->dst); 239 240 if (!tp->write_seq && likely(!tp->repair)) 241 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr, 242 inet->inet_daddr, 243 inet->inet_sport, 244 usin->sin_port); 245 246 inet->inet_id = tp->write_seq ^ jiffies; 247 248 err = tcp_connect(sk); 249 250 rt = NULL; 251 if (err) 252 goto failure; 253 254 return 0; 255 256failure: 257 /* 258 * This unhashes the socket and releases the local port, 259 * if necessary. 260 */ 261 tcp_set_state(sk, TCP_CLOSE); 262 ip_rt_put(rt); 263 sk->sk_route_caps = 0; 264 inet->inet_dport = 0; 265 return err; 266} 267EXPORT_SYMBOL(tcp_v4_connect); 268 269/* 270 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191. 271 * It can be called through tcp_release_cb() if socket was owned by user 272 * at the time tcp_v4_err() was called to handle ICMP message. 273 */ 274static void tcp_v4_mtu_reduced(struct sock *sk) 275{ 276 struct dst_entry *dst; 277 struct inet_sock *inet = inet_sk(sk); 278 u32 mtu = tcp_sk(sk)->mtu_info; 279 280 dst = inet_csk_update_pmtu(sk, mtu); 281 if (!dst) 282 return; 283 284 /* Something is about to be wrong... Remember soft error 285 * for the case, if this connection will not able to recover. 286 */ 287 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) 288 sk->sk_err_soft = EMSGSIZE; 289 290 mtu = dst_mtu(dst); 291 292 if (inet->pmtudisc != IP_PMTUDISC_DONT && 293 ip_sk_accept_pmtu(sk) && 294 inet_csk(sk)->icsk_pmtu_cookie > mtu) { 295 tcp_sync_mss(sk, mtu); 296 297 /* Resend the TCP packet because it's 298 * clear that the old packet has been 299 * dropped. This is the new "fast" path mtu 300 * discovery. 301 */ 302 tcp_simple_retransmit(sk); 303 } /* else let the usual retransmit timer handle it */ 304} 305 306static void do_redirect(struct sk_buff *skb, struct sock *sk) 307{ 308 struct dst_entry *dst = __sk_dst_check(sk, 0); 309 310 if (dst) 311 dst->ops->redirect(dst, sk, skb); 312} 313 314/* 315 * This routine is called by the ICMP module when it gets some 316 * sort of error condition. If err < 0 then the socket should 317 * be closed and the error returned to the user. If err > 0 318 * it's just the icmp type << 8 | icmp code. After adjustment 319 * header points to the first 8 bytes of the tcp header. We need 320 * to find the appropriate port. 321 * 322 * The locking strategy used here is very "optimistic". When 323 * someone else accesses the socket the ICMP is just dropped 324 * and for some paths there is no check at all. 325 * A more general error queue to queue errors for later handling 326 * is probably better. 327 * 328 */ 329 330void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) 331{ 332 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data; 333 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2)); 334 struct inet_connection_sock *icsk; 335 struct tcp_sock *tp; 336 struct inet_sock *inet; 337 const int type = icmp_hdr(icmp_skb)->type; 338 const int code = icmp_hdr(icmp_skb)->code; 339 struct sock *sk; 340 struct sk_buff *skb; 341 struct request_sock *fastopen; 342 __u32 seq, snd_una; 343 __u32 remaining; 344 int err; 345 struct net *net = dev_net(icmp_skb->dev); 346 347 sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest, 348 iph->saddr, th->source, inet_iif(icmp_skb)); 349 if (!sk) { 350 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); 351 return; 352 } 353 if (sk->sk_state == TCP_TIME_WAIT) { 354 inet_twsk_put(inet_twsk(sk)); 355 return; 356 } 357 358 bh_lock_sock(sk); 359 /* If too many ICMPs get dropped on busy 360 * servers this needs to be solved differently. 361 * We do take care of PMTU discovery (RFC1191) special case : 362 * we can receive locally generated ICMP messages while socket is held. 363 */ 364 if (sock_owned_by_user(sk)) { 365 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)) 366 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); 367 } 368 if (sk->sk_state == TCP_CLOSE) 369 goto out; 370 371 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { 372 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); 373 goto out; 374 } 375 376 icsk = inet_csk(sk); 377 tp = tcp_sk(sk); 378 seq = ntohl(th->seq); 379 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ 380 fastopen = tp->fastopen_rsk; 381 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; 382 if (sk->sk_state != TCP_LISTEN && 383 !between(seq, snd_una, tp->snd_nxt)) { 384 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); 385 goto out; 386 } 387 388 switch (type) { 389 case ICMP_REDIRECT: 390 do_redirect(icmp_skb, sk); 391 goto out; 392 case ICMP_SOURCE_QUENCH: 393 /* Just silently ignore these. */ 394 goto out; 395 case ICMP_PARAMETERPROB: 396 err = EPROTO; 397 break; 398 case ICMP_DEST_UNREACH: 399 if (code > NR_ICMP_UNREACH) 400 goto out; 401 402 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ 403 /* We are not interested in TCP_LISTEN and open_requests 404 * (SYN-ACKs send out by Linux are always <576bytes so 405 * they should go through unfragmented). 406 */ 407 if (sk->sk_state == TCP_LISTEN) 408 goto out; 409 410 tp->mtu_info = info; 411 if (!sock_owned_by_user(sk)) { 412 tcp_v4_mtu_reduced(sk); 413 } else { 414 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags)) 415 sock_hold(sk); 416 } 417 goto out; 418 } 419 420 err = icmp_err_convert[code].errno; 421 /* check if icmp_skb allows revert of backoff 422 * (see draft-zimmermann-tcp-lcd) */ 423 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH) 424 break; 425 if (seq != tp->snd_una || !icsk->icsk_retransmits || 426 !icsk->icsk_backoff || fastopen) 427 break; 428 429 if (sock_owned_by_user(sk)) 430 break; 431 432 icsk->icsk_backoff--; 433 inet_csk(sk)->icsk_rto = (tp->srtt_us ? __tcp_set_rto(tp) : 434 TCP_TIMEOUT_INIT) << icsk->icsk_backoff; 435 tcp_bound_rto(sk); 436 437 skb = tcp_write_queue_head(sk); 438 BUG_ON(!skb); 439 440 remaining = icsk->icsk_rto - min(icsk->icsk_rto, 441 tcp_time_stamp - TCP_SKB_CB(skb)->when); 442 443 if (remaining) { 444 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 445 remaining, TCP_RTO_MAX); 446 } else { 447 /* RTO revert clocked out retransmission. 448 * Will retransmit now */ 449 tcp_retransmit_timer(sk); 450 } 451 452 break; 453 case ICMP_TIME_EXCEEDED: 454 err = EHOSTUNREACH; 455 break; 456 default: 457 goto out; 458 } 459 460 switch (sk->sk_state) { 461 struct request_sock *req, **prev; 462 case TCP_LISTEN: 463 if (sock_owned_by_user(sk)) 464 goto out; 465 466 req = inet_csk_search_req(sk, &prev, th->dest, 467 iph->daddr, iph->saddr); 468 if (!req) 469 goto out; 470 471 /* ICMPs are not backlogged, hence we cannot get 472 an established socket here. 473 */ 474 WARN_ON(req->sk); 475 476 if (seq != tcp_rsk(req)->snt_isn) { 477 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); 478 goto out; 479 } 480 481 /* 482 * Still in SYN_RECV, just remove it silently. 483 * There is no good way to pass the error to the newly 484 * created socket, and POSIX does not want network 485 * errors returned from accept(). 486 */ 487 inet_csk_reqsk_queue_drop(sk, req, prev); 488 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); 489 goto out; 490 491 case TCP_SYN_SENT: 492 case TCP_SYN_RECV: 493 /* Only in fast or simultaneous open. If a fast open socket is 494 * is already accepted it is treated as a connected one below. 495 */ 496 if (fastopen && fastopen->sk == NULL) 497 break; 498 499 if (!sock_owned_by_user(sk)) { 500 sk->sk_err = err; 501 502 sk->sk_error_report(sk); 503 504 tcp_done(sk); 505 } else { 506 sk->sk_err_soft = err; 507 } 508 goto out; 509 } 510 511 /* If we've already connected we will keep trying 512 * until we time out, or the user gives up. 513 * 514 * rfc1122 4.2.3.9 allows to consider as hard errors 515 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, 516 * but it is obsoleted by pmtu discovery). 517 * 518 * Note, that in modern internet, where routing is unreliable 519 * and in each dark corner broken firewalls sit, sending random 520 * errors ordered by their masters even this two messages finally lose 521 * their original sense (even Linux sends invalid PORT_UNREACHs) 522 * 523 * Now we are in compliance with RFCs. 524 * --ANK (980905) 525 */ 526 527 inet = inet_sk(sk); 528 if (!sock_owned_by_user(sk) && inet->recverr) { 529 sk->sk_err = err; 530 sk->sk_error_report(sk); 531 } else { /* Only an error on timeout */ 532 sk->sk_err_soft = err; 533 } 534 535out: 536 bh_unlock_sock(sk); 537 sock_put(sk); 538} 539 540void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr) 541{ 542 struct tcphdr *th = tcp_hdr(skb); 543 544 if (skb->ip_summed == CHECKSUM_PARTIAL) { 545 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); 546 skb->csum_start = skb_transport_header(skb) - skb->head; 547 skb->csum_offset = offsetof(struct tcphdr, check); 548 } else { 549 th->check = tcp_v4_check(skb->len, saddr, daddr, 550 csum_partial(th, 551 th->doff << 2, 552 skb->csum)); 553 } 554} 555 556/* This routine computes an IPv4 TCP checksum. */ 557void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) 558{ 559 const struct inet_sock *inet = inet_sk(sk); 560 561 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); 562} 563EXPORT_SYMBOL(tcp_v4_send_check); 564 565/* 566 * This routine will send an RST to the other tcp. 567 * 568 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) 569 * for reset. 570 * Answer: if a packet caused RST, it is not for a socket 571 * existing in our system, if it is matched to a socket, 572 * it is just duplicate segment or bug in other side's TCP. 573 * So that we build reply only basing on parameters 574 * arrived with segment. 575 * Exception: precedence violation. We do not implement it in any case. 576 */ 577 578static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) 579{ 580 const struct tcphdr *th = tcp_hdr(skb); 581 struct { 582 struct tcphdr th; 583#ifdef CONFIG_TCP_MD5SIG 584 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)]; 585#endif 586 } rep; 587 struct ip_reply_arg arg; 588#ifdef CONFIG_TCP_MD5SIG 589 struct tcp_md5sig_key *key; 590 const __u8 *hash_location = NULL; 591 unsigned char newhash[16]; 592 int genhash; 593 struct sock *sk1 = NULL; 594#endif 595 struct net *net; 596 597 /* Never send a reset in response to a reset. */ 598 if (th->rst) 599 return; 600 601 if (skb_rtable(skb)->rt_type != RTN_LOCAL) 602 return; 603 604 /* Swap the send and the receive. */ 605 memset(&rep, 0, sizeof(rep)); 606 rep.th.dest = th->source; 607 rep.th.source = th->dest; 608 rep.th.doff = sizeof(struct tcphdr) / 4; 609 rep.th.rst = 1; 610 611 if (th->ack) { 612 rep.th.seq = th->ack_seq; 613 } else { 614 rep.th.ack = 1; 615 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + 616 skb->len - (th->doff << 2)); 617 } 618 619 memset(&arg, 0, sizeof(arg)); 620 arg.iov[0].iov_base = (unsigned char *)&rep; 621 arg.iov[0].iov_len = sizeof(rep.th); 622 623#ifdef CONFIG_TCP_MD5SIG 624 hash_location = tcp_parse_md5sig_option(th); 625 if (!sk && hash_location) { 626 /* 627 * active side is lost. Try to find listening socket through 628 * source port, and then find md5 key through listening socket. 629 * we are not loose security here: 630 * Incoming packet is checked with md5 hash with finding key, 631 * no RST generated if md5 hash doesn't match. 632 */ 633 sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev), 634 &tcp_hashinfo, ip_hdr(skb)->saddr, 635 th->source, ip_hdr(skb)->daddr, 636 ntohs(th->source), inet_iif(skb)); 637 /* don't send rst if it can't find key */ 638 if (!sk1) 639 return; 640 rcu_read_lock(); 641 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *) 642 &ip_hdr(skb)->saddr, AF_INET); 643 if (!key) 644 goto release_sk1; 645 646 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb); 647 if (genhash || memcmp(hash_location, newhash, 16) != 0) 648 goto release_sk1; 649 } else { 650 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *) 651 &ip_hdr(skb)->saddr, 652 AF_INET) : NULL; 653 } 654 655 if (key) { 656 rep.opt[0] = htonl((TCPOPT_NOP << 24) | 657 (TCPOPT_NOP << 16) | 658 (TCPOPT_MD5SIG << 8) | 659 TCPOLEN_MD5SIG); 660 /* Update length and the length the header thinks exists */ 661 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 662 rep.th.doff = arg.iov[0].iov_len / 4; 663 664 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], 665 key, ip_hdr(skb)->saddr, 666 ip_hdr(skb)->daddr, &rep.th); 667 } 668#endif 669 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 670 ip_hdr(skb)->saddr, /* XXX */ 671 arg.iov[0].iov_len, IPPROTO_TCP, 0); 672 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 673 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0; 674 /* When socket is gone, all binding information is lost. 675 * routing might fail in this case. No choice here, if we choose to force 676 * input interface, we will misroute in case of asymmetric route. 677 */ 678 if (sk) 679 arg.bound_dev_if = sk->sk_bound_dev_if; 680 681 net = dev_net(skb_dst(skb)->dev); 682 arg.tos = ip_hdr(skb)->tos; 683 ip_send_unicast_reply(net, skb, ip_hdr(skb)->saddr, 684 ip_hdr(skb)->daddr, &arg, arg.iov[0].iov_len); 685 686 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); 687 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS); 688 689#ifdef CONFIG_TCP_MD5SIG 690release_sk1: 691 if (sk1) { 692 rcu_read_unlock(); 693 sock_put(sk1); 694 } 695#endif 696} 697 698/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 699 outside socket context is ugly, certainly. What can I do? 700 */ 701 702static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, 703 u32 win, u32 tsval, u32 tsecr, int oif, 704 struct tcp_md5sig_key *key, 705 int reply_flags, u8 tos) 706{ 707 const struct tcphdr *th = tcp_hdr(skb); 708 struct { 709 struct tcphdr th; 710 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2) 711#ifdef CONFIG_TCP_MD5SIG 712 + (TCPOLEN_MD5SIG_ALIGNED >> 2) 713#endif 714 ]; 715 } rep; 716 struct ip_reply_arg arg; 717 struct net *net = dev_net(skb_dst(skb)->dev); 718 719 memset(&rep.th, 0, sizeof(struct tcphdr)); 720 memset(&arg, 0, sizeof(arg)); 721 722 arg.iov[0].iov_base = (unsigned char *)&rep; 723 arg.iov[0].iov_len = sizeof(rep.th); 724 if (tsecr) { 725 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 726 (TCPOPT_TIMESTAMP << 8) | 727 TCPOLEN_TIMESTAMP); 728 rep.opt[1] = htonl(tsval); 729 rep.opt[2] = htonl(tsecr); 730 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; 731 } 732 733 /* Swap the send and the receive. */ 734 rep.th.dest = th->source; 735 rep.th.source = th->dest; 736 rep.th.doff = arg.iov[0].iov_len / 4; 737 rep.th.seq = htonl(seq); 738 rep.th.ack_seq = htonl(ack); 739 rep.th.ack = 1; 740 rep.th.window = htons(win); 741 742#ifdef CONFIG_TCP_MD5SIG 743 if (key) { 744 int offset = (tsecr) ? 3 : 0; 745 746 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | 747 (TCPOPT_NOP << 16) | 748 (TCPOPT_MD5SIG << 8) | 749 TCPOLEN_MD5SIG); 750 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 751 rep.th.doff = arg.iov[0].iov_len/4; 752 753 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], 754 key, ip_hdr(skb)->saddr, 755 ip_hdr(skb)->daddr, &rep.th); 756 } 757#endif 758 arg.flags = reply_flags; 759 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 760 ip_hdr(skb)->saddr, /* XXX */ 761 arg.iov[0].iov_len, IPPROTO_TCP, 0); 762 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 763 if (oif) 764 arg.bound_dev_if = oif; 765 arg.tos = tos; 766 ip_send_unicast_reply(net, skb, ip_hdr(skb)->saddr, 767 ip_hdr(skb)->daddr, &arg, arg.iov[0].iov_len); 768 769 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); 770} 771 772static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 773{ 774 struct inet_timewait_sock *tw = inet_twsk(sk); 775 struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 776 777 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 778 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, 779 tcp_time_stamp + tcptw->tw_ts_offset, 780 tcptw->tw_ts_recent, 781 tw->tw_bound_dev_if, 782 tcp_twsk_md5_key(tcptw), 783 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, 784 tw->tw_tos 785 ); 786 787 inet_twsk_put(tw); 788} 789 790static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, 791 struct request_sock *req) 792{ 793 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV 794 * sk->sk_state == TCP_SYN_RECV -> for Fast Open. 795 */ 796 tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ? 797 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, 798 tcp_rsk(req)->rcv_nxt, req->rcv_wnd, 799 tcp_time_stamp, 800 req->ts_recent, 801 0, 802 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr, 803 AF_INET), 804 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, 805 ip_hdr(skb)->tos); 806} 807 808/* 809 * Send a SYN-ACK after having received a SYN. 810 * This still operates on a request_sock only, not on a big 811 * socket. 812 */ 813static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst, 814 struct flowi *fl, 815 struct request_sock *req, 816 u16 queue_mapping, 817 struct tcp_fastopen_cookie *foc) 818{ 819 const struct inet_request_sock *ireq = inet_rsk(req); 820 struct flowi4 fl4; 821 int err = -1; 822 struct sk_buff *skb; 823 824 /* First, grab a route. */ 825 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) 826 return -1; 827 828 skb = tcp_make_synack(sk, dst, req, foc); 829 830 if (skb) { 831 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); 832 833 skb_set_queue_mapping(skb, queue_mapping); 834 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, 835 ireq->ir_rmt_addr, 836 ireq->opt); 837 err = net_xmit_eval(err); 838 } 839 840 return err; 841} 842 843/* 844 * IPv4 request_sock destructor. 845 */ 846static void tcp_v4_reqsk_destructor(struct request_sock *req) 847{ 848 kfree(inet_rsk(req)->opt); 849} 850 851/* 852 * Return true if a syncookie should be sent 853 */ 854bool tcp_syn_flood_action(struct sock *sk, 855 const struct sk_buff *skb, 856 const char *proto) 857{ 858 const char *msg = "Dropping request"; 859 bool want_cookie = false; 860 struct listen_sock *lopt; 861 862#ifdef CONFIG_SYN_COOKIES 863 if (sysctl_tcp_syncookies) { 864 msg = "Sending cookies"; 865 want_cookie = true; 866 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES); 867 } else 868#endif 869 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP); 870 871 lopt = inet_csk(sk)->icsk_accept_queue.listen_opt; 872 if (!lopt->synflood_warned && sysctl_tcp_syncookies != 2) { 873 lopt->synflood_warned = 1; 874 pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n", 875 proto, ntohs(tcp_hdr(skb)->dest), msg); 876 } 877 return want_cookie; 878} 879EXPORT_SYMBOL(tcp_syn_flood_action); 880 881/* 882 * Save and compile IPv4 options into the request_sock if needed. 883 */ 884static struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb) 885{ 886 const struct ip_options *opt = &(IPCB(skb)->opt); 887 struct ip_options_rcu *dopt = NULL; 888 889 if (opt && opt->optlen) { 890 int opt_size = sizeof(*dopt) + opt->optlen; 891 892 dopt = kmalloc(opt_size, GFP_ATOMIC); 893 if (dopt) { 894 if (ip_options_echo(&dopt->opt, skb)) { 895 kfree(dopt); 896 dopt = NULL; 897 } 898 } 899 } 900 return dopt; 901} 902 903#ifdef CONFIG_TCP_MD5SIG 904/* 905 * RFC2385 MD5 checksumming requires a mapping of 906 * IP address->MD5 Key. 907 * We need to maintain these in the sk structure. 908 */ 909 910/* Find the Key structure for an address. */ 911struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk, 912 const union tcp_md5_addr *addr, 913 int family) 914{ 915 struct tcp_sock *tp = tcp_sk(sk); 916 struct tcp_md5sig_key *key; 917 unsigned int size = sizeof(struct in_addr); 918 struct tcp_md5sig_info *md5sig; 919 920 /* caller either holds rcu_read_lock() or socket lock */ 921 md5sig = rcu_dereference_check(tp->md5sig_info, 922 sock_owned_by_user(sk) || 923 lockdep_is_held(&sk->sk_lock.slock)); 924 if (!md5sig) 925 return NULL; 926#if IS_ENABLED(CONFIG_IPV6) 927 if (family == AF_INET6) 928 size = sizeof(struct in6_addr); 929#endif 930 hlist_for_each_entry_rcu(key, &md5sig->head, node) { 931 if (key->family != family) 932 continue; 933 if (!memcmp(&key->addr, addr, size)) 934 return key; 935 } 936 return NULL; 937} 938EXPORT_SYMBOL(tcp_md5_do_lookup); 939 940struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk, 941 struct sock *addr_sk) 942{ 943 union tcp_md5_addr *addr; 944 945 addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr; 946 return tcp_md5_do_lookup(sk, addr, AF_INET); 947} 948EXPORT_SYMBOL(tcp_v4_md5_lookup); 949 950static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk, 951 struct request_sock *req) 952{ 953 union tcp_md5_addr *addr; 954 955 addr = (union tcp_md5_addr *)&inet_rsk(req)->ir_rmt_addr; 956 return tcp_md5_do_lookup(sk, addr, AF_INET); 957} 958 959/* This can be called on a newly created socket, from other files */ 960int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 961 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp) 962{ 963 /* Add Key to the list */ 964 struct tcp_md5sig_key *key; 965 struct tcp_sock *tp = tcp_sk(sk); 966 struct tcp_md5sig_info *md5sig; 967 968 key = tcp_md5_do_lookup(sk, addr, family); 969 if (key) { 970 /* Pre-existing entry - just update that one. */ 971 memcpy(key->key, newkey, newkeylen); 972 key->keylen = newkeylen; 973 return 0; 974 } 975 976 md5sig = rcu_dereference_protected(tp->md5sig_info, 977 sock_owned_by_user(sk)); 978 if (!md5sig) { 979 md5sig = kmalloc(sizeof(*md5sig), gfp); 980 if (!md5sig) 981 return -ENOMEM; 982 983 sk_nocaps_add(sk, NETIF_F_GSO_MASK); 984 INIT_HLIST_HEAD(&md5sig->head); 985 rcu_assign_pointer(tp->md5sig_info, md5sig); 986 } 987 988 key = sock_kmalloc(sk, sizeof(*key), gfp); 989 if (!key) 990 return -ENOMEM; 991 if (!tcp_alloc_md5sig_pool()) { 992 sock_kfree_s(sk, key, sizeof(*key)); 993 return -ENOMEM; 994 } 995 996 memcpy(key->key, newkey, newkeylen); 997 key->keylen = newkeylen; 998 key->family = family; 999 memcpy(&key->addr, addr, 1000 (family == AF_INET6) ? sizeof(struct in6_addr) : 1001 sizeof(struct in_addr)); 1002 hlist_add_head_rcu(&key->node, &md5sig->head); 1003 return 0; 1004} 1005EXPORT_SYMBOL(tcp_md5_do_add); 1006 1007int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family) 1008{ 1009 struct tcp_md5sig_key *key; 1010 1011 key = tcp_md5_do_lookup(sk, addr, family); 1012 if (!key) 1013 return -ENOENT; 1014 hlist_del_rcu(&key->node); 1015 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1016 kfree_rcu(key, rcu); 1017 return 0; 1018} 1019EXPORT_SYMBOL(tcp_md5_do_del); 1020 1021static void tcp_clear_md5_list(struct sock *sk) 1022{ 1023 struct tcp_sock *tp = tcp_sk(sk); 1024 struct tcp_md5sig_key *key; 1025 struct hlist_node *n; 1026 struct tcp_md5sig_info *md5sig; 1027 1028 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 1029 1030 hlist_for_each_entry_safe(key, n, &md5sig->head, node) { 1031 hlist_del_rcu(&key->node); 1032 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 1033 kfree_rcu(key, rcu); 1034 } 1035} 1036 1037static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval, 1038 int optlen) 1039{ 1040 struct tcp_md5sig cmd; 1041 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; 1042 1043 if (optlen < sizeof(cmd)) 1044 return -EINVAL; 1045 1046 if (copy_from_user(&cmd, optval, sizeof(cmd))) 1047 return -EFAULT; 1048 1049 if (sin->sin_family != AF_INET) 1050 return -EINVAL; 1051 1052 if (!cmd.tcpm_keylen) 1053 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, 1054 AF_INET); 1055 1056 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) 1057 return -EINVAL; 1058 1059 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, 1060 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, 1061 GFP_KERNEL); 1062} 1063 1064static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp, 1065 __be32 daddr, __be32 saddr, int nbytes) 1066{ 1067 struct tcp4_pseudohdr *bp; 1068 struct scatterlist sg; 1069 1070 bp = &hp->md5_blk.ip4; 1071 1072 /* 1073 * 1. the TCP pseudo-header (in the order: source IP address, 1074 * destination IP address, zero-padded protocol number, and 1075 * segment length) 1076 */ 1077 bp->saddr = saddr; 1078 bp->daddr = daddr; 1079 bp->pad = 0; 1080 bp->protocol = IPPROTO_TCP; 1081 bp->len = cpu_to_be16(nbytes); 1082 1083 sg_init_one(&sg, bp, sizeof(*bp)); 1084 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp)); 1085} 1086 1087static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 1088 __be32 daddr, __be32 saddr, const struct tcphdr *th) 1089{ 1090 struct tcp_md5sig_pool *hp; 1091 struct hash_desc *desc; 1092 1093 hp = tcp_get_md5sig_pool(); 1094 if (!hp) 1095 goto clear_hash_noput; 1096 desc = &hp->md5_desc; 1097 1098 if (crypto_hash_init(desc)) 1099 goto clear_hash; 1100 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2)) 1101 goto clear_hash; 1102 if (tcp_md5_hash_header(hp, th)) 1103 goto clear_hash; 1104 if (tcp_md5_hash_key(hp, key)) 1105 goto clear_hash; 1106 if (crypto_hash_final(desc, md5_hash)) 1107 goto clear_hash; 1108 1109 tcp_put_md5sig_pool(); 1110 return 0; 1111 1112clear_hash: 1113 tcp_put_md5sig_pool(); 1114clear_hash_noput: 1115 memset(md5_hash, 0, 16); 1116 return 1; 1117} 1118 1119int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key, 1120 const struct sock *sk, const struct request_sock *req, 1121 const struct sk_buff *skb) 1122{ 1123 struct tcp_md5sig_pool *hp; 1124 struct hash_desc *desc; 1125 const struct tcphdr *th = tcp_hdr(skb); 1126 __be32 saddr, daddr; 1127 1128 if (sk) { 1129 saddr = inet_sk(sk)->inet_saddr; 1130 daddr = inet_sk(sk)->inet_daddr; 1131 } else if (req) { 1132 saddr = inet_rsk(req)->ir_loc_addr; 1133 daddr = inet_rsk(req)->ir_rmt_addr; 1134 } else { 1135 const struct iphdr *iph = ip_hdr(skb); 1136 saddr = iph->saddr; 1137 daddr = iph->daddr; 1138 } 1139 1140 hp = tcp_get_md5sig_pool(); 1141 if (!hp) 1142 goto clear_hash_noput; 1143 desc = &hp->md5_desc; 1144 1145 if (crypto_hash_init(desc)) 1146 goto clear_hash; 1147 1148 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len)) 1149 goto clear_hash; 1150 if (tcp_md5_hash_header(hp, th)) 1151 goto clear_hash; 1152 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) 1153 goto clear_hash; 1154 if (tcp_md5_hash_key(hp, key)) 1155 goto clear_hash; 1156 if (crypto_hash_final(desc, md5_hash)) 1157 goto clear_hash; 1158 1159 tcp_put_md5sig_pool(); 1160 return 0; 1161 1162clear_hash: 1163 tcp_put_md5sig_pool(); 1164clear_hash_noput: 1165 memset(md5_hash, 0, 16); 1166 return 1; 1167} 1168EXPORT_SYMBOL(tcp_v4_md5_hash_skb); 1169 1170static bool __tcp_v4_inbound_md5_hash(struct sock *sk, 1171 const struct sk_buff *skb) 1172{ 1173 /* 1174 * This gets called for each TCP segment that arrives 1175 * so we want to be efficient. 1176 * We have 3 drop cases: 1177 * o No MD5 hash and one expected. 1178 * o MD5 hash and we're not expecting one. 1179 * o MD5 hash and its wrong. 1180 */ 1181 const __u8 *hash_location = NULL; 1182 struct tcp_md5sig_key *hash_expected; 1183 const struct iphdr *iph = ip_hdr(skb); 1184 const struct tcphdr *th = tcp_hdr(skb); 1185 int genhash; 1186 unsigned char newhash[16]; 1187 1188 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr, 1189 AF_INET); 1190 hash_location = tcp_parse_md5sig_option(th); 1191 1192 /* We've parsed the options - do we have a hash? */ 1193 if (!hash_expected && !hash_location) 1194 return false; 1195 1196 if (hash_expected && !hash_location) { 1197 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); 1198 return true; 1199 } 1200 1201 if (!hash_expected && hash_location) { 1202 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); 1203 return true; 1204 } 1205 1206 /* Okay, so this is hash_expected and hash_location - 1207 * so we need to calculate the checksum. 1208 */ 1209 genhash = tcp_v4_md5_hash_skb(newhash, 1210 hash_expected, 1211 NULL, NULL, skb); 1212 1213 if (genhash || memcmp(hash_location, newhash, 16) != 0) { 1214 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n", 1215 &iph->saddr, ntohs(th->source), 1216 &iph->daddr, ntohs(th->dest), 1217 genhash ? " tcp_v4_calc_md5_hash failed" 1218 : ""); 1219 return true; 1220 } 1221 return false; 1222} 1223 1224static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb) 1225{ 1226 bool ret; 1227 1228 rcu_read_lock(); 1229 ret = __tcp_v4_inbound_md5_hash(sk, skb); 1230 rcu_read_unlock(); 1231 1232 return ret; 1233} 1234 1235#endif 1236 1237static void tcp_v4_init_req(struct request_sock *req, struct sock *sk, 1238 struct sk_buff *skb) 1239{ 1240 struct inet_request_sock *ireq = inet_rsk(req); 1241 1242 ireq->ir_loc_addr = ip_hdr(skb)->daddr; 1243 ireq->ir_rmt_addr = ip_hdr(skb)->saddr; 1244 ireq->no_srccheck = inet_sk(sk)->transparent; 1245 ireq->opt = tcp_v4_save_options(skb); 1246} 1247 1248static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl, 1249 const struct request_sock *req, 1250 bool *strict) 1251{ 1252 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req); 1253 1254 if (strict) { 1255 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr) 1256 *strict = true; 1257 else 1258 *strict = false; 1259 } 1260 1261 return dst; 1262} 1263 1264struct request_sock_ops tcp_request_sock_ops __read_mostly = { 1265 .family = PF_INET, 1266 .obj_size = sizeof(struct tcp_request_sock), 1267 .rtx_syn_ack = tcp_rtx_synack, 1268 .send_ack = tcp_v4_reqsk_send_ack, 1269 .destructor = tcp_v4_reqsk_destructor, 1270 .send_reset = tcp_v4_send_reset, 1271 .syn_ack_timeout = tcp_syn_ack_timeout, 1272}; 1273 1274static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { 1275 .mss_clamp = TCP_MSS_DEFAULT, 1276#ifdef CONFIG_TCP_MD5SIG 1277 .md5_lookup = tcp_v4_reqsk_md5_lookup, 1278 .calc_md5_hash = tcp_v4_md5_hash_skb, 1279#endif 1280 .init_req = tcp_v4_init_req, 1281#ifdef CONFIG_SYN_COOKIES 1282 .cookie_init_seq = cookie_v4_init_sequence, 1283#endif 1284 .route_req = tcp_v4_route_req, 1285 .init_seq = tcp_v4_init_sequence, 1286 .send_synack = tcp_v4_send_synack, 1287 .queue_hash_add = inet_csk_reqsk_queue_hash_add, 1288}; 1289 1290int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 1291{ 1292 /* Never answer to SYNs send to broadcast or multicast */ 1293 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) 1294 goto drop; 1295 1296 return tcp_conn_request(&tcp_request_sock_ops, 1297 &tcp_request_sock_ipv4_ops, sk, skb); 1298 1299drop: 1300 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); 1301 return 0; 1302} 1303EXPORT_SYMBOL(tcp_v4_conn_request); 1304 1305 1306/* 1307 * The three way handshake has completed - we got a valid synack - 1308 * now create the new socket. 1309 */ 1310struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, 1311 struct request_sock *req, 1312 struct dst_entry *dst) 1313{ 1314 struct inet_request_sock *ireq; 1315 struct inet_sock *newinet; 1316 struct tcp_sock *newtp; 1317 struct sock *newsk; 1318#ifdef CONFIG_TCP_MD5SIG 1319 struct tcp_md5sig_key *key; 1320#endif 1321 struct ip_options_rcu *inet_opt; 1322 1323 if (sk_acceptq_is_full(sk)) 1324 goto exit_overflow; 1325 1326 newsk = tcp_create_openreq_child(sk, req, skb); 1327 if (!newsk) 1328 goto exit_nonewsk; 1329 1330 newsk->sk_gso_type = SKB_GSO_TCPV4; 1331 inet_sk_rx_dst_set(newsk, skb); 1332 1333 newtp = tcp_sk(newsk); 1334 newinet = inet_sk(newsk); 1335 ireq = inet_rsk(req); 1336 newinet->inet_daddr = ireq->ir_rmt_addr; 1337 newinet->inet_rcv_saddr = ireq->ir_loc_addr; 1338 newinet->inet_saddr = ireq->ir_loc_addr; 1339 inet_opt = ireq->opt; 1340 rcu_assign_pointer(newinet->inet_opt, inet_opt); 1341 ireq->opt = NULL; 1342 newinet->mc_index = inet_iif(skb); 1343 newinet->mc_ttl = ip_hdr(skb)->ttl; 1344 newinet->rcv_tos = ip_hdr(skb)->tos; 1345 inet_csk(newsk)->icsk_ext_hdr_len = 0; 1346 inet_set_txhash(newsk); 1347 if (inet_opt) 1348 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 1349 newinet->inet_id = newtp->write_seq ^ jiffies; 1350 1351 if (!dst) { 1352 dst = inet_csk_route_child_sock(sk, newsk, req); 1353 if (!dst) 1354 goto put_and_exit; 1355 } else { 1356 /* syncookie case : see end of cookie_v4_check() */ 1357 } 1358 sk_setup_caps(newsk, dst); 1359 1360 tcp_sync_mss(newsk, dst_mtu(dst)); 1361 newtp->advmss = dst_metric_advmss(dst); 1362 if (tcp_sk(sk)->rx_opt.user_mss && 1363 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss) 1364 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss; 1365 1366 tcp_initialize_rcv_mss(newsk); 1367 1368#ifdef CONFIG_TCP_MD5SIG 1369 /* Copy over the MD5 key from the original socket */ 1370 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr, 1371 AF_INET); 1372 if (key != NULL) { 1373 /* 1374 * We're using one, so create a matching key 1375 * on the newsk structure. If we fail to get 1376 * memory, then we end up not copying the key 1377 * across. Shucks. 1378 */ 1379 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr, 1380 AF_INET, key->key, key->keylen, GFP_ATOMIC); 1381 sk_nocaps_add(newsk, NETIF_F_GSO_MASK); 1382 } 1383#endif 1384 1385 if (__inet_inherit_port(sk, newsk) < 0) 1386 goto put_and_exit; 1387 __inet_hash_nolisten(newsk, NULL); 1388 1389 return newsk; 1390 1391exit_overflow: 1392 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 1393exit_nonewsk: 1394 dst_release(dst); 1395exit: 1396 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); 1397 return NULL; 1398put_and_exit: 1399 inet_csk_prepare_forced_close(newsk); 1400 tcp_done(newsk); 1401 goto exit; 1402} 1403EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 1404 1405static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) 1406{ 1407 struct tcphdr *th = tcp_hdr(skb); 1408 const struct iphdr *iph = ip_hdr(skb); 1409 struct sock *nsk; 1410 struct request_sock **prev; 1411 /* Find possible connection requests. */ 1412 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source, 1413 iph->saddr, iph->daddr); 1414 if (req) 1415 return tcp_check_req(sk, skb, req, prev, false); 1416 1417 nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr, 1418 th->source, iph->daddr, th->dest, inet_iif(skb)); 1419 1420 if (nsk) { 1421 if (nsk->sk_state != TCP_TIME_WAIT) { 1422 bh_lock_sock(nsk); 1423 return nsk; 1424 } 1425 inet_twsk_put(inet_twsk(nsk)); 1426 return NULL; 1427 } 1428 1429#ifdef CONFIG_SYN_COOKIES 1430 if (!th->syn) 1431 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt)); 1432#endif 1433 return sk; 1434} 1435 1436/* The socket must have it's spinlock held when we get 1437 * here. 1438 * 1439 * We have a potential double-lock case here, so even when 1440 * doing backlog processing we use the BH locking scheme. 1441 * This is because we cannot sleep with the original spinlock 1442 * held. 1443 */ 1444int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1445{ 1446 struct sock *rsk; 1447 1448 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1449 struct dst_entry *dst = sk->sk_rx_dst; 1450 1451 sock_rps_save_rxhash(sk, skb); 1452 if (dst) { 1453 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif || 1454 dst->ops->check(dst, 0) == NULL) { 1455 dst_release(dst); 1456 sk->sk_rx_dst = NULL; 1457 } 1458 } 1459 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len); 1460 return 0; 1461 } 1462 1463 if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb)) 1464 goto csum_err; 1465 1466 if (sk->sk_state == TCP_LISTEN) { 1467 struct sock *nsk = tcp_v4_hnd_req(sk, skb); 1468 if (!nsk) 1469 goto discard; 1470 1471 if (nsk != sk) { 1472 sock_rps_save_rxhash(nsk, skb); 1473 if (tcp_child_process(sk, nsk, skb)) { 1474 rsk = nsk; 1475 goto reset; 1476 } 1477 return 0; 1478 } 1479 } else 1480 sock_rps_save_rxhash(sk, skb); 1481 1482 if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) { 1483 rsk = sk; 1484 goto reset; 1485 } 1486 return 0; 1487 1488reset: 1489 tcp_v4_send_reset(rsk, skb); 1490discard: 1491 kfree_skb(skb); 1492 /* Be careful here. If this function gets more complicated and 1493 * gcc suffers from register pressure on the x86, sk (in %ebx) 1494 * might be destroyed here. This current version compiles correctly, 1495 * but you have been warned. 1496 */ 1497 return 0; 1498 1499csum_err: 1500 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS); 1501 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); 1502 goto discard; 1503} 1504EXPORT_SYMBOL(tcp_v4_do_rcv); 1505 1506void tcp_v4_early_demux(struct sk_buff *skb) 1507{ 1508 const struct iphdr *iph; 1509 const struct tcphdr *th; 1510 struct sock *sk; 1511 1512 if (skb->pkt_type != PACKET_HOST) 1513 return; 1514 1515 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) 1516 return; 1517 1518 iph = ip_hdr(skb); 1519 th = tcp_hdr(skb); 1520 1521 if (th->doff < sizeof(struct tcphdr) / 4) 1522 return; 1523 1524 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo, 1525 iph->saddr, th->source, 1526 iph->daddr, ntohs(th->dest), 1527 skb->skb_iif); 1528 if (sk) { 1529 skb->sk = sk; 1530 skb->destructor = sock_edemux; 1531 if (sk->sk_state != TCP_TIME_WAIT) { 1532 struct dst_entry *dst = sk->sk_rx_dst; 1533 1534 if (dst) 1535 dst = dst_check(dst, 0); 1536 if (dst && 1537 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif) 1538 skb_dst_set_noref(skb, dst); 1539 } 1540 } 1541} 1542 1543/* Packet is added to VJ-style prequeue for processing in process 1544 * context, if a reader task is waiting. Apparently, this exciting 1545 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 1546 * failed somewhere. Latency? Burstiness? Well, at least now we will 1547 * see, why it failed. 8)8) --ANK 1548 * 1549 */ 1550bool tcp_prequeue(struct sock *sk, struct sk_buff *skb) 1551{ 1552 struct tcp_sock *tp = tcp_sk(sk); 1553 1554 if (sysctl_tcp_low_latency || !tp->ucopy.task) 1555 return false; 1556 1557 if (skb->len <= tcp_hdrlen(skb) && 1558 skb_queue_len(&tp->ucopy.prequeue) == 0) 1559 return false; 1560 1561 skb_dst_force(skb); 1562 __skb_queue_tail(&tp->ucopy.prequeue, skb); 1563 tp->ucopy.memory += skb->truesize; 1564 if (tp->ucopy.memory > sk->sk_rcvbuf) { 1565 struct sk_buff *skb1; 1566 1567 BUG_ON(sock_owned_by_user(sk)); 1568 1569 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 1570 sk_backlog_rcv(sk, skb1); 1571 NET_INC_STATS_BH(sock_net(sk), 1572 LINUX_MIB_TCPPREQUEUEDROPPED); 1573 } 1574 1575 tp->ucopy.memory = 0; 1576 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 1577 wake_up_interruptible_sync_poll(sk_sleep(sk), 1578 POLLIN | POLLRDNORM | POLLRDBAND); 1579 if (!inet_csk_ack_scheduled(sk)) 1580 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 1581 (3 * tcp_rto_min(sk)) / 4, 1582 TCP_RTO_MAX); 1583 } 1584 return true; 1585} 1586EXPORT_SYMBOL(tcp_prequeue); 1587 1588/* 1589 * From tcp_input.c 1590 */ 1591 1592int tcp_v4_rcv(struct sk_buff *skb) 1593{ 1594 const struct iphdr *iph; 1595 const struct tcphdr *th; 1596 struct sock *sk; 1597 int ret; 1598 struct net *net = dev_net(skb->dev); 1599 1600 if (skb->pkt_type != PACKET_HOST) 1601 goto discard_it; 1602 1603 /* Count it even if it's bad */ 1604 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS); 1605 1606 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 1607 goto discard_it; 1608 1609 th = tcp_hdr(skb); 1610 1611 if (th->doff < sizeof(struct tcphdr) / 4) 1612 goto bad_packet; 1613 if (!pskb_may_pull(skb, th->doff * 4)) 1614 goto discard_it; 1615 1616 /* An explanation is required here, I think. 1617 * Packet length and doff are validated by header prediction, 1618 * provided case of th->doff==0 is eliminated. 1619 * So, we defer the checks. */ 1620 1621 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo)) 1622 goto csum_error; 1623 1624 th = tcp_hdr(skb); 1625 iph = ip_hdr(skb); 1626 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 1627 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 1628 skb->len - th->doff * 4); 1629 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 1630 TCP_SKB_CB(skb)->when = 0; 1631 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); 1632 TCP_SKB_CB(skb)->sacked = 0; 1633 1634 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest); 1635 if (!sk) 1636 goto no_tcp_socket; 1637 1638process: 1639 if (sk->sk_state == TCP_TIME_WAIT) 1640 goto do_time_wait; 1641 1642 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { 1643 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); 1644 goto discard_and_relse; 1645 } 1646 1647 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 1648 goto discard_and_relse; 1649 1650#ifdef CONFIG_TCP_MD5SIG 1651 /* 1652 * We really want to reject the packet as early as possible 1653 * if: 1654 * o We're expecting an MD5'd packet and this is no MD5 tcp option 1655 * o There is an MD5 option and we're not expecting one 1656 */ 1657 if (tcp_v4_inbound_md5_hash(sk, skb)) 1658 goto discard_and_relse; 1659#endif 1660 1661 nf_reset(skb); 1662 1663 if (sk_filter(sk, skb)) 1664 goto discard_and_relse; 1665 1666 sk_mark_napi_id(sk, skb); 1667 skb->dev = NULL; 1668 1669 bh_lock_sock_nested(sk); 1670 ret = 0; 1671 if (!sock_owned_by_user(sk)) { 1672#ifdef CONFIG_NET_DMA 1673 struct tcp_sock *tp = tcp_sk(sk); 1674 if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list) 1675 tp->ucopy.dma_chan = net_dma_find_channel(); 1676 if (tp->ucopy.dma_chan) 1677 ret = tcp_v4_do_rcv(sk, skb); 1678 else 1679#endif 1680 { 1681 if (!tcp_prequeue(sk, skb)) 1682 ret = tcp_v4_do_rcv(sk, skb); 1683 } 1684 } else if (unlikely(sk_add_backlog(sk, skb, 1685 sk->sk_rcvbuf + sk->sk_sndbuf))) { 1686 bh_unlock_sock(sk); 1687 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP); 1688 goto discard_and_relse; 1689 } 1690 bh_unlock_sock(sk); 1691 1692 sock_put(sk); 1693 1694 return ret; 1695 1696no_tcp_socket: 1697 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 1698 goto discard_it; 1699 1700 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { 1701csum_error: 1702 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS); 1703bad_packet: 1704 TCP_INC_STATS_BH(net, TCP_MIB_INERRS); 1705 } else { 1706 tcp_v4_send_reset(NULL, skb); 1707 } 1708 1709discard_it: 1710 /* Discard frame. */ 1711 kfree_skb(skb); 1712 return 0; 1713 1714discard_and_relse: 1715 sock_put(sk); 1716 goto discard_it; 1717 1718do_time_wait: 1719 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 1720 inet_twsk_put(inet_twsk(sk)); 1721 goto discard_it; 1722 } 1723 1724 if (skb->len < (th->doff << 2)) { 1725 inet_twsk_put(inet_twsk(sk)); 1726 goto bad_packet; 1727 } 1728 if (tcp_checksum_complete(skb)) { 1729 inet_twsk_put(inet_twsk(sk)); 1730 goto csum_error; 1731 } 1732 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { 1733 case TCP_TW_SYN: { 1734 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev), 1735 &tcp_hashinfo, 1736 iph->saddr, th->source, 1737 iph->daddr, th->dest, 1738 inet_iif(skb)); 1739 if (sk2) { 1740 inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row); 1741 inet_twsk_put(inet_twsk(sk)); 1742 sk = sk2; 1743 goto process; 1744 } 1745 /* Fall through to ACK */ 1746 } 1747 case TCP_TW_ACK: 1748 tcp_v4_timewait_ack(sk, skb); 1749 break; 1750 case TCP_TW_RST: 1751 goto no_tcp_socket; 1752 case TCP_TW_SUCCESS:; 1753 } 1754 goto discard_it; 1755} 1756 1757static struct timewait_sock_ops tcp_timewait_sock_ops = { 1758 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 1759 .twsk_unique = tcp_twsk_unique, 1760 .twsk_destructor= tcp_twsk_destructor, 1761}; 1762 1763void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 1764{ 1765 struct dst_entry *dst = skb_dst(skb); 1766 1767 dst_hold(dst); 1768 sk->sk_rx_dst = dst; 1769 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; 1770} 1771EXPORT_SYMBOL(inet_sk_rx_dst_set); 1772 1773const struct inet_connection_sock_af_ops ipv4_specific = { 1774 .queue_xmit = ip_queue_xmit, 1775 .send_check = tcp_v4_send_check, 1776 .rebuild_header = inet_sk_rebuild_header, 1777 .sk_rx_dst_set = inet_sk_rx_dst_set, 1778 .conn_request = tcp_v4_conn_request, 1779 .syn_recv_sock = tcp_v4_syn_recv_sock, 1780 .net_header_len = sizeof(struct iphdr), 1781 .setsockopt = ip_setsockopt, 1782 .getsockopt = ip_getsockopt, 1783 .addr2sockaddr = inet_csk_addr2sockaddr, 1784 .sockaddr_len = sizeof(struct sockaddr_in), 1785 .bind_conflict = inet_csk_bind_conflict, 1786#ifdef CONFIG_COMPAT 1787 .compat_setsockopt = compat_ip_setsockopt, 1788 .compat_getsockopt = compat_ip_getsockopt, 1789#endif 1790}; 1791EXPORT_SYMBOL(ipv4_specific); 1792 1793#ifdef CONFIG_TCP_MD5SIG 1794static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { 1795 .md5_lookup = tcp_v4_md5_lookup, 1796 .calc_md5_hash = tcp_v4_md5_hash_skb, 1797 .md5_parse = tcp_v4_parse_md5_keys, 1798}; 1799#endif 1800 1801/* NOTE: A lot of things set to zero explicitly by call to 1802 * sk_alloc() so need not be done here. 1803 */ 1804static int tcp_v4_init_sock(struct sock *sk) 1805{ 1806 struct inet_connection_sock *icsk = inet_csk(sk); 1807 1808 tcp_init_sock(sk); 1809 1810 icsk->icsk_af_ops = &ipv4_specific; 1811 1812#ifdef CONFIG_TCP_MD5SIG 1813 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific; 1814#endif 1815 1816 return 0; 1817} 1818 1819void tcp_v4_destroy_sock(struct sock *sk) 1820{ 1821 struct tcp_sock *tp = tcp_sk(sk); 1822 1823 tcp_clear_xmit_timers(sk); 1824 1825 tcp_cleanup_congestion_control(sk); 1826 1827 /* Cleanup up the write buffer. */ 1828 tcp_write_queue_purge(sk); 1829 1830 /* Cleans up our, hopefully empty, out_of_order_queue. */ 1831 __skb_queue_purge(&tp->out_of_order_queue); 1832 1833#ifdef CONFIG_TCP_MD5SIG 1834 /* Clean up the MD5 key list, if any */ 1835 if (tp->md5sig_info) { 1836 tcp_clear_md5_list(sk); 1837 kfree_rcu(tp->md5sig_info, rcu); 1838 tp->md5sig_info = NULL; 1839 } 1840#endif 1841 1842#ifdef CONFIG_NET_DMA 1843 /* Cleans up our sk_async_wait_queue */ 1844 __skb_queue_purge(&sk->sk_async_wait_queue); 1845#endif 1846 1847 /* Clean prequeue, it must be empty really */ 1848 __skb_queue_purge(&tp->ucopy.prequeue); 1849 1850 /* Clean up a referenced TCP bind bucket. */ 1851 if (inet_csk(sk)->icsk_bind_hash) 1852 inet_put_port(sk); 1853 1854 BUG_ON(tp->fastopen_rsk != NULL); 1855 1856 /* If socket is aborted during connect operation */ 1857 tcp_free_fastopen_req(tp); 1858 1859 sk_sockets_allocated_dec(sk); 1860 sock_release_memcg(sk); 1861} 1862EXPORT_SYMBOL(tcp_v4_destroy_sock); 1863 1864#ifdef CONFIG_PROC_FS 1865/* Proc filesystem TCP sock list dumping. */ 1866 1867/* 1868 * Get next listener socket follow cur. If cur is NULL, get first socket 1869 * starting from bucket given in st->bucket; when st->bucket is zero the 1870 * very first socket in the hash table is returned. 1871 */ 1872static void *listening_get_next(struct seq_file *seq, void *cur) 1873{ 1874 struct inet_connection_sock *icsk; 1875 struct hlist_nulls_node *node; 1876 struct sock *sk = cur; 1877 struct inet_listen_hashbucket *ilb; 1878 struct tcp_iter_state *st = seq->private; 1879 struct net *net = seq_file_net(seq); 1880 1881 if (!sk) { 1882 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1883 spin_lock_bh(&ilb->lock); 1884 sk = sk_nulls_head(&ilb->head); 1885 st->offset = 0; 1886 goto get_sk; 1887 } 1888 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1889 ++st->num; 1890 ++st->offset; 1891 1892 if (st->state == TCP_SEQ_STATE_OPENREQ) { 1893 struct request_sock *req = cur; 1894 1895 icsk = inet_csk(st->syn_wait_sk); 1896 req = req->dl_next; 1897 while (1) { 1898 while (req) { 1899 if (req->rsk_ops->family == st->family) { 1900 cur = req; 1901 goto out; 1902 } 1903 req = req->dl_next; 1904 } 1905 if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries) 1906 break; 1907get_req: 1908 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket]; 1909 } 1910 sk = sk_nulls_next(st->syn_wait_sk); 1911 st->state = TCP_SEQ_STATE_LISTENING; 1912 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1913 } else { 1914 icsk = inet_csk(sk); 1915 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1916 if (reqsk_queue_len(&icsk->icsk_accept_queue)) 1917 goto start_req; 1918 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1919 sk = sk_nulls_next(sk); 1920 } 1921get_sk: 1922 sk_nulls_for_each_from(sk, node) { 1923 if (!net_eq(sock_net(sk), net)) 1924 continue; 1925 if (sk->sk_family == st->family) { 1926 cur = sk; 1927 goto out; 1928 } 1929 icsk = inet_csk(sk); 1930 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1931 if (reqsk_queue_len(&icsk->icsk_accept_queue)) { 1932start_req: 1933 st->uid = sock_i_uid(sk); 1934 st->syn_wait_sk = sk; 1935 st->state = TCP_SEQ_STATE_OPENREQ; 1936 st->sbucket = 0; 1937 goto get_req; 1938 } 1939 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1940 } 1941 spin_unlock_bh(&ilb->lock); 1942 st->offset = 0; 1943 if (++st->bucket < INET_LHTABLE_SIZE) { 1944 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1945 spin_lock_bh(&ilb->lock); 1946 sk = sk_nulls_head(&ilb->head); 1947 goto get_sk; 1948 } 1949 cur = NULL; 1950out: 1951 return cur; 1952} 1953 1954static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 1955{ 1956 struct tcp_iter_state *st = seq->private; 1957 void *rc; 1958 1959 st->bucket = 0; 1960 st->offset = 0; 1961 rc = listening_get_next(seq, NULL); 1962 1963 while (rc && *pos) { 1964 rc = listening_get_next(seq, rc); 1965 --*pos; 1966 } 1967 return rc; 1968} 1969 1970static inline bool empty_bucket(const struct tcp_iter_state *st) 1971{ 1972 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain); 1973} 1974 1975/* 1976 * Get first established socket starting from bucket given in st->bucket. 1977 * If st->bucket is zero, the very first socket in the hash is returned. 1978 */ 1979static void *established_get_first(struct seq_file *seq) 1980{ 1981 struct tcp_iter_state *st = seq->private; 1982 struct net *net = seq_file_net(seq); 1983 void *rc = NULL; 1984 1985 st->offset = 0; 1986 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) { 1987 struct sock *sk; 1988 struct hlist_nulls_node *node; 1989 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket); 1990 1991 /* Lockless fast path for the common case of empty buckets */ 1992 if (empty_bucket(st)) 1993 continue; 1994 1995 spin_lock_bh(lock); 1996 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { 1997 if (sk->sk_family != st->family || 1998 !net_eq(sock_net(sk), net)) { 1999 continue; 2000 } 2001 rc = sk; 2002 goto out; 2003 } 2004 spin_unlock_bh(lock); 2005 } 2006out: 2007 return rc; 2008} 2009 2010static void *established_get_next(struct seq_file *seq, void *cur) 2011{ 2012 struct sock *sk = cur; 2013 struct hlist_nulls_node *node; 2014 struct tcp_iter_state *st = seq->private; 2015 struct net *net = seq_file_net(seq); 2016 2017 ++st->num; 2018 ++st->offset; 2019 2020 sk = sk_nulls_next(sk); 2021 2022 sk_nulls_for_each_from(sk, node) { 2023 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) 2024 return sk; 2025 } 2026 2027 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); 2028 ++st->bucket; 2029 return established_get_first(seq); 2030} 2031 2032static void *established_get_idx(struct seq_file *seq, loff_t pos) 2033{ 2034 struct tcp_iter_state *st = seq->private; 2035 void *rc; 2036 2037 st->bucket = 0; 2038 rc = established_get_first(seq); 2039 2040 while (rc && pos) { 2041 rc = established_get_next(seq, rc); 2042 --pos; 2043 } 2044 return rc; 2045} 2046 2047static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 2048{ 2049 void *rc; 2050 struct tcp_iter_state *st = seq->private; 2051 2052 st->state = TCP_SEQ_STATE_LISTENING; 2053 rc = listening_get_idx(seq, &pos); 2054 2055 if (!rc) { 2056 st->state = TCP_SEQ_STATE_ESTABLISHED; 2057 rc = established_get_idx(seq, pos); 2058 } 2059 2060 return rc; 2061} 2062 2063static void *tcp_seek_last_pos(struct seq_file *seq) 2064{ 2065 struct tcp_iter_state *st = seq->private; 2066 int offset = st->offset; 2067 int orig_num = st->num; 2068 void *rc = NULL; 2069 2070 switch (st->state) { 2071 case TCP_SEQ_STATE_OPENREQ: 2072 case TCP_SEQ_STATE_LISTENING: 2073 if (st->bucket >= INET_LHTABLE_SIZE) 2074 break; 2075 st->state = TCP_SEQ_STATE_LISTENING; 2076 rc = listening_get_next(seq, NULL); 2077 while (offset-- && rc) 2078 rc = listening_get_next(seq, rc); 2079 if (rc) 2080 break; 2081 st->bucket = 0; 2082 st->state = TCP_SEQ_STATE_ESTABLISHED; 2083 /* Fallthrough */ 2084 case TCP_SEQ_STATE_ESTABLISHED: 2085 if (st->bucket > tcp_hashinfo.ehash_mask) 2086 break; 2087 rc = established_get_first(seq); 2088 while (offset-- && rc) 2089 rc = established_get_next(seq, rc); 2090 } 2091 2092 st->num = orig_num; 2093 2094 return rc; 2095} 2096 2097static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 2098{ 2099 struct tcp_iter_state *st = seq->private; 2100 void *rc; 2101 2102 if (*pos && *pos == st->last_pos) { 2103 rc = tcp_seek_last_pos(seq); 2104 if (rc) 2105 goto out; 2106 } 2107 2108 st->state = TCP_SEQ_STATE_LISTENING; 2109 st->num = 0; 2110 st->bucket = 0; 2111 st->offset = 0; 2112 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 2113 2114out: 2115 st->last_pos = *pos; 2116 return rc; 2117} 2118 2119static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2120{ 2121 struct tcp_iter_state *st = seq->private; 2122 void *rc = NULL; 2123 2124 if (v == SEQ_START_TOKEN) { 2125 rc = tcp_get_idx(seq, 0); 2126 goto out; 2127 } 2128 2129 switch (st->state) { 2130 case TCP_SEQ_STATE_OPENREQ: 2131 case TCP_SEQ_STATE_LISTENING: 2132 rc = listening_get_next(seq, v); 2133 if (!rc) { 2134 st->state = TCP_SEQ_STATE_ESTABLISHED; 2135 st->bucket = 0; 2136 st->offset = 0; 2137 rc = established_get_first(seq); 2138 } 2139 break; 2140 case TCP_SEQ_STATE_ESTABLISHED: 2141 rc = established_get_next(seq, v); 2142 break; 2143 } 2144out: 2145 ++*pos; 2146 st->last_pos = *pos; 2147 return rc; 2148} 2149 2150static void tcp_seq_stop(struct seq_file *seq, void *v) 2151{ 2152 struct tcp_iter_state *st = seq->private; 2153 2154 switch (st->state) { 2155 case TCP_SEQ_STATE_OPENREQ: 2156 if (v) { 2157 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk); 2158 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 2159 } 2160 case TCP_SEQ_STATE_LISTENING: 2161 if (v != SEQ_START_TOKEN) 2162 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock); 2163 break; 2164 case TCP_SEQ_STATE_ESTABLISHED: 2165 if (v) 2166 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); 2167 break; 2168 } 2169} 2170 2171int tcp_seq_open(struct inode *inode, struct file *file) 2172{ 2173 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode); 2174 struct tcp_iter_state *s; 2175 int err; 2176 2177 err = seq_open_net(inode, file, &afinfo->seq_ops, 2178 sizeof(struct tcp_iter_state)); 2179 if (err < 0) 2180 return err; 2181 2182 s = ((struct seq_file *)file->private_data)->private; 2183 s->family = afinfo->family; 2184 s->last_pos = 0; 2185 return 0; 2186} 2187EXPORT_SYMBOL(tcp_seq_open); 2188 2189int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo) 2190{ 2191 int rc = 0; 2192 struct proc_dir_entry *p; 2193 2194 afinfo->seq_ops.start = tcp_seq_start; 2195 afinfo->seq_ops.next = tcp_seq_next; 2196 afinfo->seq_ops.stop = tcp_seq_stop; 2197 2198 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net, 2199 afinfo->seq_fops, afinfo); 2200 if (!p) 2201 rc = -ENOMEM; 2202 return rc; 2203} 2204EXPORT_SYMBOL(tcp_proc_register); 2205 2206void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo) 2207{ 2208 remove_proc_entry(afinfo->name, net->proc_net); 2209} 2210EXPORT_SYMBOL(tcp_proc_unregister); 2211 2212static void get_openreq4(const struct sock *sk, const struct request_sock *req, 2213 struct seq_file *f, int i, kuid_t uid) 2214{ 2215 const struct inet_request_sock *ireq = inet_rsk(req); 2216 long delta = req->expires - jiffies; 2217 2218 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2219 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK", 2220 i, 2221 ireq->ir_loc_addr, 2222 ntohs(inet_sk(sk)->inet_sport), 2223 ireq->ir_rmt_addr, 2224 ntohs(ireq->ir_rmt_port), 2225 TCP_SYN_RECV, 2226 0, 0, /* could print option size, but that is af dependent. */ 2227 1, /* timers active (only the expire timer) */ 2228 jiffies_delta_to_clock_t(delta), 2229 req->num_timeout, 2230 from_kuid_munged(seq_user_ns(f), uid), 2231 0, /* non standard timer */ 2232 0, /* open_requests have no inode */ 2233 atomic_read(&sk->sk_refcnt), 2234 req); 2235} 2236 2237static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) 2238{ 2239 int timer_active; 2240 unsigned long timer_expires; 2241 const struct tcp_sock *tp = tcp_sk(sk); 2242 const struct inet_connection_sock *icsk = inet_csk(sk); 2243 const struct inet_sock *inet = inet_sk(sk); 2244 struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq; 2245 __be32 dest = inet->inet_daddr; 2246 __be32 src = inet->inet_rcv_saddr; 2247 __u16 destp = ntohs(inet->inet_dport); 2248 __u16 srcp = ntohs(inet->inet_sport); 2249 int rx_queue; 2250 2251 if (icsk->icsk_pending == ICSK_TIME_RETRANS || 2252 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS || 2253 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { 2254 timer_active = 1; 2255 timer_expires = icsk->icsk_timeout; 2256 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 2257 timer_active = 4; 2258 timer_expires = icsk->icsk_timeout; 2259 } else if (timer_pending(&sk->sk_timer)) { 2260 timer_active = 2; 2261 timer_expires = sk->sk_timer.expires; 2262 } else { 2263 timer_active = 0; 2264 timer_expires = jiffies; 2265 } 2266 2267 if (sk->sk_state == TCP_LISTEN) 2268 rx_queue = sk->sk_ack_backlog; 2269 else 2270 /* 2271 * because we dont lock socket, we might find a transient negative value 2272 */ 2273 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0); 2274 2275 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 2276 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d", 2277 i, src, srcp, dest, destp, sk->sk_state, 2278 tp->write_seq - tp->snd_una, 2279 rx_queue, 2280 timer_active, 2281 jiffies_delta_to_clock_t(timer_expires - jiffies), 2282 icsk->icsk_retransmits, 2283 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)), 2284 icsk->icsk_probes_out, 2285 sock_i_ino(sk), 2286 atomic_read(&sk->sk_refcnt), sk, 2287 jiffies_to_clock_t(icsk->icsk_rto), 2288 jiffies_to_clock_t(icsk->icsk_ack.ato), 2289 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, 2290 tp->snd_cwnd, 2291 sk->sk_state == TCP_LISTEN ? 2292 (fastopenq ? fastopenq->max_qlen : 0) : 2293 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); 2294} 2295 2296static void get_timewait4_sock(const struct inet_timewait_sock *tw, 2297 struct seq_file *f, int i) 2298{ 2299 __be32 dest, src; 2300 __u16 destp, srcp; 2301 s32 delta = tw->tw_ttd - inet_tw_time_stamp(); 2302 2303 dest = tw->tw_daddr; 2304 src = tw->tw_rcv_saddr; 2305 destp = ntohs(tw->tw_dport); 2306 srcp = ntohs(tw->tw_sport); 2307 2308 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2309 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK", 2310 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 2311 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, 2312 atomic_read(&tw->tw_refcnt), tw); 2313} 2314 2315#define TMPSZ 150 2316 2317static int tcp4_seq_show(struct seq_file *seq, void *v) 2318{ 2319 struct tcp_iter_state *st; 2320 struct sock *sk = v; 2321 2322 seq_setwidth(seq, TMPSZ - 1); 2323 if (v == SEQ_START_TOKEN) { 2324 seq_puts(seq, " sl local_address rem_address st tx_queue " 2325 "rx_queue tr tm->when retrnsmt uid timeout " 2326 "inode"); 2327 goto out; 2328 } 2329 st = seq->private; 2330 2331 switch (st->state) { 2332 case TCP_SEQ_STATE_LISTENING: 2333 case TCP_SEQ_STATE_ESTABLISHED: 2334 if (sk->sk_state == TCP_TIME_WAIT) 2335 get_timewait4_sock(v, seq, st->num); 2336 else 2337 get_tcp4_sock(v, seq, st->num); 2338 break; 2339 case TCP_SEQ_STATE_OPENREQ: 2340 get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid); 2341 break; 2342 } 2343out: 2344 seq_pad(seq, '\n'); 2345 return 0; 2346} 2347 2348static const struct file_operations tcp_afinfo_seq_fops = { 2349 .owner = THIS_MODULE, 2350 .open = tcp_seq_open, 2351 .read = seq_read, 2352 .llseek = seq_lseek, 2353 .release = seq_release_net 2354}; 2355 2356static struct tcp_seq_afinfo tcp4_seq_afinfo = { 2357 .name = "tcp", 2358 .family = AF_INET, 2359 .seq_fops = &tcp_afinfo_seq_fops, 2360 .seq_ops = { 2361 .show = tcp4_seq_show, 2362 }, 2363}; 2364 2365static int __net_init tcp4_proc_init_net(struct net *net) 2366{ 2367 return tcp_proc_register(net, &tcp4_seq_afinfo); 2368} 2369 2370static void __net_exit tcp4_proc_exit_net(struct net *net) 2371{ 2372 tcp_proc_unregister(net, &tcp4_seq_afinfo); 2373} 2374 2375static struct pernet_operations tcp4_net_ops = { 2376 .init = tcp4_proc_init_net, 2377 .exit = tcp4_proc_exit_net, 2378}; 2379 2380int __init tcp4_proc_init(void) 2381{ 2382 return register_pernet_subsys(&tcp4_net_ops); 2383} 2384 2385void tcp4_proc_exit(void) 2386{ 2387 unregister_pernet_subsys(&tcp4_net_ops); 2388} 2389#endif /* CONFIG_PROC_FS */ 2390 2391struct proto tcp_prot = { 2392 .name = "TCP", 2393 .owner = THIS_MODULE, 2394 .close = tcp_close, 2395 .connect = tcp_v4_connect, 2396 .disconnect = tcp_disconnect, 2397 .accept = inet_csk_accept, 2398 .ioctl = tcp_ioctl, 2399 .init = tcp_v4_init_sock, 2400 .destroy = tcp_v4_destroy_sock, 2401 .shutdown = tcp_shutdown, 2402 .setsockopt = tcp_setsockopt, 2403 .getsockopt = tcp_getsockopt, 2404 .recvmsg = tcp_recvmsg, 2405 .sendmsg = tcp_sendmsg, 2406 .sendpage = tcp_sendpage, 2407 .backlog_rcv = tcp_v4_do_rcv, 2408 .release_cb = tcp_release_cb, 2409 .mtu_reduced = tcp_v4_mtu_reduced, 2410 .hash = inet_hash, 2411 .unhash = inet_unhash, 2412 .get_port = inet_csk_get_port, 2413 .enter_memory_pressure = tcp_enter_memory_pressure, 2414 .stream_memory_free = tcp_stream_memory_free, 2415 .sockets_allocated = &tcp_sockets_allocated, 2416 .orphan_count = &tcp_orphan_count, 2417 .memory_allocated = &tcp_memory_allocated, 2418 .memory_pressure = &tcp_memory_pressure, 2419 .sysctl_mem = sysctl_tcp_mem, 2420 .sysctl_wmem = sysctl_tcp_wmem, 2421 .sysctl_rmem = sysctl_tcp_rmem, 2422 .max_header = MAX_TCP_HEADER, 2423 .obj_size = sizeof(struct tcp_sock), 2424 .slab_flags = SLAB_DESTROY_BY_RCU, 2425 .twsk_prot = &tcp_timewait_sock_ops, 2426 .rsk_prot = &tcp_request_sock_ops, 2427 .h.hashinfo = &tcp_hashinfo, 2428 .no_autobind = true, 2429#ifdef CONFIG_COMPAT 2430 .compat_setsockopt = compat_tcp_setsockopt, 2431 .compat_getsockopt = compat_tcp_getsockopt, 2432#endif 2433#ifdef CONFIG_MEMCG_KMEM 2434 .init_cgroup = tcp_init_cgroup, 2435 .destroy_cgroup = tcp_destroy_cgroup, 2436 .proto_cgroup = tcp_proto_cgroup, 2437#endif 2438}; 2439EXPORT_SYMBOL(tcp_prot); 2440 2441static int __net_init tcp_sk_init(struct net *net) 2442{ 2443 net->ipv4.sysctl_tcp_ecn = 2; 2444 return 0; 2445} 2446 2447static void __net_exit tcp_sk_exit(struct net *net) 2448{ 2449} 2450 2451static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) 2452{ 2453 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET); 2454} 2455 2456static struct pernet_operations __net_initdata tcp_sk_ops = { 2457 .init = tcp_sk_init, 2458 .exit = tcp_sk_exit, 2459 .exit_batch = tcp_sk_exit_batch, 2460}; 2461 2462void __init tcp_v4_init(void) 2463{ 2464 inet_hashinfo_init(&tcp_hashinfo); 2465 if (register_pernet_subsys(&tcp_sk_ops)) 2466 panic("Failed to create the TCP control socket.\n"); 2467} 2468