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/tcp_memcontrol.h> 77 #include <net/busy_poll.h> 78 79 #include <linux/inet.h> 80 #include <linux/ipv6.h> 81 #include <linux/stddef.h> 82 #include <linux/proc_fs.h> 83 #include <linux/seq_file.h> 84 85 #include <linux/crypto.h> 86 #include <linux/scatterlist.h> 87 88 int sysctl_tcp_tw_reuse __read_mostly; 89 int sysctl_tcp_low_latency __read_mostly; 90 EXPORT_SYMBOL(sysctl_tcp_low_latency); 91 92 #ifdef CONFIG_TCP_MD5SIG 93 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 94 __be32 daddr, __be32 saddr, const struct tcphdr *th); 95 #endif 96 97 struct inet_hashinfo tcp_hashinfo; 98 EXPORT_SYMBOL(tcp_hashinfo); 99 100 static __u32 tcp_v4_init_sequence(const struct sk_buff *skb) 101 { 102 return secure_tcp_sequence_number(ip_hdr(skb)->daddr, 103 ip_hdr(skb)->saddr, 104 tcp_hdr(skb)->dest, 105 tcp_hdr(skb)->source); 106 } 107 108 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 109 { 110 const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); 111 struct tcp_sock *tp = tcp_sk(sk); 112 113 /* With PAWS, it is safe from the viewpoint 114 of data integrity. Even without PAWS it is safe provided sequence 115 spaces do not overlap i.e. at data rates <= 80Mbit/sec. 116 117 Actually, the idea is close to VJ's one, only timestamp cache is 118 held not per host, but per port pair and TW bucket is used as state 119 holder. 120 121 If TW bucket has been already destroyed we fall back to VJ's scheme 122 and use initial timestamp retrieved from peer table. 123 */ 124 if (tcptw->tw_ts_recent_stamp && 125 (!twp || (sysctl_tcp_tw_reuse && 126 get_seconds() - tcptw->tw_ts_recent_stamp > 1))) { 127 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; 128 if (tp->write_seq == 0) 129 tp->write_seq = 1; 130 tp->rx_opt.ts_recent = tcptw->tw_ts_recent; 131 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; 132 sock_hold(sktw); 133 return 1; 134 } 135 136 return 0; 137 } 138 EXPORT_SYMBOL_GPL(tcp_twsk_unique); 139 140 /* This will initiate an outgoing connection. */ 141 int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 142 { 143 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; 144 struct inet_sock *inet = inet_sk(sk); 145 struct tcp_sock *tp = tcp_sk(sk); 146 __be16 orig_sport, orig_dport; 147 __be32 daddr, nexthop; 148 struct flowi4 *fl4; 149 struct rtable *rt; 150 int err; 151 struct ip_options_rcu *inet_opt; 152 153 if (addr_len < sizeof(struct sockaddr_in)) 154 return -EINVAL; 155 156 if (usin->sin_family != AF_INET) 157 return -EAFNOSUPPORT; 158 159 nexthop = daddr = usin->sin_addr.s_addr; 160 inet_opt = rcu_dereference_protected(inet->inet_opt, 161 sock_owned_by_user(sk)); 162 if (inet_opt && inet_opt->opt.srr) { 163 if (!daddr) 164 return -EINVAL; 165 nexthop = inet_opt->opt.faddr; 166 } 167 168 orig_sport = inet->inet_sport; 169 orig_dport = usin->sin_port; 170 fl4 = &inet->cork.fl.u.ip4; 171 rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, 172 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, 173 IPPROTO_TCP, 174 orig_sport, orig_dport, sk); 175 if (IS_ERR(rt)) { 176 err = PTR_ERR(rt); 177 if (err == -ENETUNREACH) 178 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); 179 return err; 180 } 181 182 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 183 ip_rt_put(rt); 184 return -ENETUNREACH; 185 } 186 187 if (!inet_opt || !inet_opt->opt.srr) 188 daddr = fl4->daddr; 189 190 if (!inet->inet_saddr) 191 inet->inet_saddr = fl4->saddr; 192 sk_rcv_saddr_set(sk, inet->inet_saddr); 193 194 if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) { 195 /* Reset inherited state */ 196 tp->rx_opt.ts_recent = 0; 197 tp->rx_opt.ts_recent_stamp = 0; 198 if (likely(!tp->repair)) 199 tp->write_seq = 0; 200 } 201 202 if (tcp_death_row.sysctl_tw_recycle && 203 !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) 204 tcp_fetch_timewait_stamp(sk, &rt->dst); 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); 237 238 if (!tp->write_seq && likely(!tp->repair)) 239 tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr, 240 inet->inet_daddr, 241 inet->inet_sport, 242 usin->sin_port); 243 244 inet->inet_id = tp->write_seq ^ jiffies; 245 246 err = tcp_connect(sk); 247 248 rt = NULL; 249 if (err) 250 goto failure; 251 252 return 0; 253 254 failure: 255 /* 256 * This unhashes the socket and releases the local port, 257 * if necessary. 258 */ 259 tcp_set_state(sk, TCP_CLOSE); 260 ip_rt_put(rt); 261 sk->sk_route_caps = 0; 262 inet->inet_dport = 0; 263 return err; 264 } 265 EXPORT_SYMBOL(tcp_v4_connect); 266 267 /* 268 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191. 269 * It can be called through tcp_release_cb() if socket was owned by user 270 * at the time tcp_v4_err() was called to handle ICMP message. 271 */ 272 void tcp_v4_mtu_reduced(struct sock *sk) 273 { 274 struct dst_entry *dst; 275 struct inet_sock *inet = inet_sk(sk); 276 u32 mtu = tcp_sk(sk)->mtu_info; 277 278 dst = inet_csk_update_pmtu(sk, mtu); 279 if (!dst) 280 return; 281 282 /* Something is about to be wrong... Remember soft error 283 * for the case, if this connection will not able to recover. 284 */ 285 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) 286 sk->sk_err_soft = EMSGSIZE; 287 288 mtu = dst_mtu(dst); 289 290 if (inet->pmtudisc != IP_PMTUDISC_DONT && 291 ip_sk_accept_pmtu(sk) && 292 inet_csk(sk)->icsk_pmtu_cookie > mtu) { 293 tcp_sync_mss(sk, mtu); 294 295 /* Resend the TCP packet because it's 296 * clear that the old packet has been 297 * dropped. This is the new "fast" path mtu 298 * discovery. 299 */ 300 tcp_simple_retransmit(sk); 301 } /* else let the usual retransmit timer handle it */ 302 } 303 EXPORT_SYMBOL(tcp_v4_mtu_reduced); 304 305 static void do_redirect(struct sk_buff *skb, struct sock *sk) 306 { 307 struct dst_entry *dst = __sk_dst_check(sk, 0); 308 309 if (dst) 310 dst->ops->redirect(dst, sk, skb); 311 } 312 313 314 /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */ 315 void tcp_req_err(struct sock *sk, u32 seq) 316 { 317 struct request_sock *req = inet_reqsk(sk); 318 struct net *net = sock_net(sk); 319 320 /* ICMPs are not backlogged, hence we cannot get 321 * an established socket here. 322 */ 323 WARN_ON(req->sk); 324 325 if (seq != tcp_rsk(req)->snt_isn) { 326 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); 327 } else { 328 /* 329 * Still in SYN_RECV, just remove it silently. 330 * There is no good way to pass the error to the newly 331 * created socket, and POSIX does not want network 332 * errors returned from accept(). 333 */ 334 inet_csk_reqsk_queue_drop(req->rsk_listener, req); 335 NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS); 336 } 337 reqsk_put(req); 338 } 339 EXPORT_SYMBOL(tcp_req_err); 340 341 /* 342 * This routine is called by the ICMP module when it gets some 343 * sort of error condition. If err < 0 then the socket should 344 * be closed and the error returned to the user. If err > 0 345 * it's just the icmp type << 8 | icmp code. After adjustment 346 * header points to the first 8 bytes of the tcp header. We need 347 * to find the appropriate port. 348 * 349 * The locking strategy used here is very "optimistic". When 350 * someone else accesses the socket the ICMP is just dropped 351 * and for some paths there is no check at all. 352 * A more general error queue to queue errors for later handling 353 * is probably better. 354 * 355 */ 356 357 void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) 358 { 359 const struct iphdr *iph = (const struct iphdr *)icmp_skb->data; 360 struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2)); 361 struct inet_connection_sock *icsk; 362 struct tcp_sock *tp; 363 struct inet_sock *inet; 364 const int type = icmp_hdr(icmp_skb)->type; 365 const int code = icmp_hdr(icmp_skb)->code; 366 struct sock *sk; 367 struct sk_buff *skb; 368 struct request_sock *fastopen; 369 __u32 seq, snd_una; 370 __u32 remaining; 371 int err; 372 struct net *net = dev_net(icmp_skb->dev); 373 374 sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr, 375 th->dest, iph->saddr, ntohs(th->source), 376 inet_iif(icmp_skb)); 377 if (!sk) { 378 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); 379 return; 380 } 381 if (sk->sk_state == TCP_TIME_WAIT) { 382 inet_twsk_put(inet_twsk(sk)); 383 return; 384 } 385 seq = ntohl(th->seq); 386 if (sk->sk_state == TCP_NEW_SYN_RECV) 387 return tcp_req_err(sk, seq); 388 389 bh_lock_sock(sk); 390 /* If too many ICMPs get dropped on busy 391 * servers this needs to be solved differently. 392 * We do take care of PMTU discovery (RFC1191) special case : 393 * we can receive locally generated ICMP messages while socket is held. 394 */ 395 if (sock_owned_by_user(sk)) { 396 if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)) 397 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); 398 } 399 if (sk->sk_state == TCP_CLOSE) 400 goto out; 401 402 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { 403 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); 404 goto out; 405 } 406 407 icsk = inet_csk(sk); 408 tp = tcp_sk(sk); 409 /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ 410 fastopen = tp->fastopen_rsk; 411 snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; 412 if (sk->sk_state != TCP_LISTEN && 413 !between(seq, snd_una, tp->snd_nxt)) { 414 NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS); 415 goto out; 416 } 417 418 switch (type) { 419 case ICMP_REDIRECT: 420 do_redirect(icmp_skb, sk); 421 goto out; 422 case ICMP_SOURCE_QUENCH: 423 /* Just silently ignore these. */ 424 goto out; 425 case ICMP_PARAMETERPROB: 426 err = EPROTO; 427 break; 428 case ICMP_DEST_UNREACH: 429 if (code > NR_ICMP_UNREACH) 430 goto out; 431 432 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ 433 /* We are not interested in TCP_LISTEN and open_requests 434 * (SYN-ACKs send out by Linux are always <576bytes so 435 * they should go through unfragmented). 436 */ 437 if (sk->sk_state == TCP_LISTEN) 438 goto out; 439 440 tp->mtu_info = info; 441 if (!sock_owned_by_user(sk)) { 442 tcp_v4_mtu_reduced(sk); 443 } else { 444 if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags)) 445 sock_hold(sk); 446 } 447 goto out; 448 } 449 450 err = icmp_err_convert[code].errno; 451 /* check if icmp_skb allows revert of backoff 452 * (see draft-zimmermann-tcp-lcd) */ 453 if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH) 454 break; 455 if (seq != tp->snd_una || !icsk->icsk_retransmits || 456 !icsk->icsk_backoff || fastopen) 457 break; 458 459 if (sock_owned_by_user(sk)) 460 break; 461 462 icsk->icsk_backoff--; 463 icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : 464 TCP_TIMEOUT_INIT; 465 icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX); 466 467 skb = tcp_write_queue_head(sk); 468 BUG_ON(!skb); 469 470 remaining = icsk->icsk_rto - 471 min(icsk->icsk_rto, 472 tcp_time_stamp - tcp_skb_timestamp(skb)); 473 474 if (remaining) { 475 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 476 remaining, TCP_RTO_MAX); 477 } else { 478 /* RTO revert clocked out retransmission. 479 * Will retransmit now */ 480 tcp_retransmit_timer(sk); 481 } 482 483 break; 484 case ICMP_TIME_EXCEEDED: 485 err = EHOSTUNREACH; 486 break; 487 default: 488 goto out; 489 } 490 491 switch (sk->sk_state) { 492 case TCP_SYN_SENT: 493 case TCP_SYN_RECV: 494 /* Only in fast or simultaneous open. If a fast open socket is 495 * is already accepted it is treated as a connected one below. 496 */ 497 if (fastopen && !fastopen->sk) 498 break; 499 500 if (!sock_owned_by_user(sk)) { 501 sk->sk_err = err; 502 503 sk->sk_error_report(sk); 504 505 tcp_done(sk); 506 } else { 507 sk->sk_err_soft = err; 508 } 509 goto out; 510 } 511 512 /* If we've already connected we will keep trying 513 * until we time out, or the user gives up. 514 * 515 * rfc1122 4.2.3.9 allows to consider as hard errors 516 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, 517 * but it is obsoleted by pmtu discovery). 518 * 519 * Note, that in modern internet, where routing is unreliable 520 * and in each dark corner broken firewalls sit, sending random 521 * errors ordered by their masters even this two messages finally lose 522 * their original sense (even Linux sends invalid PORT_UNREACHs) 523 * 524 * Now we are in compliance with RFCs. 525 * --ANK (980905) 526 */ 527 528 inet = inet_sk(sk); 529 if (!sock_owned_by_user(sk) && inet->recverr) { 530 sk->sk_err = err; 531 sk->sk_error_report(sk); 532 } else { /* Only an error on timeout */ 533 sk->sk_err_soft = err; 534 } 535 536 out: 537 bh_unlock_sock(sk); 538 sock_put(sk); 539 } 540 541 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr) 542 { 543 struct tcphdr *th = tcp_hdr(skb); 544 545 if (skb->ip_summed == CHECKSUM_PARTIAL) { 546 th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); 547 skb->csum_start = skb_transport_header(skb) - skb->head; 548 skb->csum_offset = offsetof(struct tcphdr, check); 549 } else { 550 th->check = tcp_v4_check(skb->len, saddr, daddr, 551 csum_partial(th, 552 th->doff << 2, 553 skb->csum)); 554 } 555 } 556 557 /* This routine computes an IPv4 TCP checksum. */ 558 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) 559 { 560 const struct inet_sock *inet = inet_sk(sk); 561 562 __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); 563 } 564 EXPORT_SYMBOL(tcp_v4_send_check); 565 566 /* 567 * This routine will send an RST to the other tcp. 568 * 569 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) 570 * for reset. 571 * Answer: if a packet caused RST, it is not for a socket 572 * existing in our system, if it is matched to a socket, 573 * it is just duplicate segment or bug in other side's TCP. 574 * So that we build reply only basing on parameters 575 * arrived with segment. 576 * Exception: precedence violation. We do not implement it in any case. 577 */ 578 579 static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) 580 { 581 const struct tcphdr *th = tcp_hdr(skb); 582 struct { 583 struct tcphdr th; 584 #ifdef CONFIG_TCP_MD5SIG 585 __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)]; 586 #endif 587 } rep; 588 struct ip_reply_arg arg; 589 #ifdef CONFIG_TCP_MD5SIG 590 struct tcp_md5sig_key *key; 591 const __u8 *hash_location = NULL; 592 unsigned char newhash[16]; 593 int genhash; 594 struct sock *sk1 = NULL; 595 #endif 596 struct net *net; 597 598 /* Never send a reset in response to a reset. */ 599 if (th->rst) 600 return; 601 602 /* If sk not NULL, it means we did a successful lookup and incoming 603 * route had to be correct. prequeue might have dropped our dst. 604 */ 605 if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL) 606 return; 607 608 /* Swap the send and the receive. */ 609 memset(&rep, 0, sizeof(rep)); 610 rep.th.dest = th->source; 611 rep.th.source = th->dest; 612 rep.th.doff = sizeof(struct tcphdr) / 4; 613 rep.th.rst = 1; 614 615 if (th->ack) { 616 rep.th.seq = th->ack_seq; 617 } else { 618 rep.th.ack = 1; 619 rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + 620 skb->len - (th->doff << 2)); 621 } 622 623 memset(&arg, 0, sizeof(arg)); 624 arg.iov[0].iov_base = (unsigned char *)&rep; 625 arg.iov[0].iov_len = sizeof(rep.th); 626 627 net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); 628 #ifdef CONFIG_TCP_MD5SIG 629 hash_location = tcp_parse_md5sig_option(th); 630 if (!sk && hash_location) { 631 /* 632 * active side is lost. Try to find listening socket through 633 * source port, and then find md5 key through listening socket. 634 * we are not loose security here: 635 * Incoming packet is checked with md5 hash with finding key, 636 * no RST generated if md5 hash doesn't match. 637 */ 638 sk1 = __inet_lookup_listener(net, 639 &tcp_hashinfo, ip_hdr(skb)->saddr, 640 th->source, ip_hdr(skb)->daddr, 641 ntohs(th->source), inet_iif(skb)); 642 /* don't send rst if it can't find key */ 643 if (!sk1) 644 return; 645 rcu_read_lock(); 646 key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *) 647 &ip_hdr(skb)->saddr, AF_INET); 648 if (!key) 649 goto release_sk1; 650 651 genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); 652 if (genhash || memcmp(hash_location, newhash, 16) != 0) 653 goto release_sk1; 654 } else { 655 key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *) 656 &ip_hdr(skb)->saddr, 657 AF_INET) : NULL; 658 } 659 660 if (key) { 661 rep.opt[0] = htonl((TCPOPT_NOP << 24) | 662 (TCPOPT_NOP << 16) | 663 (TCPOPT_MD5SIG << 8) | 664 TCPOLEN_MD5SIG); 665 /* Update length and the length the header thinks exists */ 666 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 667 rep.th.doff = arg.iov[0].iov_len / 4; 668 669 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], 670 key, ip_hdr(skb)->saddr, 671 ip_hdr(skb)->daddr, &rep.th); 672 } 673 #endif 674 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 675 ip_hdr(skb)->saddr, /* XXX */ 676 arg.iov[0].iov_len, IPPROTO_TCP, 0); 677 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 678 arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0; 679 /* When socket is gone, all binding information is lost. 680 * routing might fail in this case. No choice here, if we choose to force 681 * input interface, we will misroute in case of asymmetric route. 682 */ 683 if (sk) 684 arg.bound_dev_if = sk->sk_bound_dev_if; 685 686 arg.tos = ip_hdr(skb)->tos; 687 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), 688 skb, &TCP_SKB_CB(skb)->header.h4.opt, 689 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 690 &arg, arg.iov[0].iov_len); 691 692 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); 693 TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS); 694 695 #ifdef CONFIG_TCP_MD5SIG 696 release_sk1: 697 if (sk1) { 698 rcu_read_unlock(); 699 sock_put(sk1); 700 } 701 #endif 702 } 703 704 /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 705 outside socket context is ugly, certainly. What can I do? 706 */ 707 708 static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, 709 u32 win, u32 tsval, u32 tsecr, int oif, 710 struct tcp_md5sig_key *key, 711 int reply_flags, u8 tos) 712 { 713 const struct tcphdr *th = tcp_hdr(skb); 714 struct { 715 struct tcphdr th; 716 __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2) 717 #ifdef CONFIG_TCP_MD5SIG 718 + (TCPOLEN_MD5SIG_ALIGNED >> 2) 719 #endif 720 ]; 721 } rep; 722 struct ip_reply_arg arg; 723 struct net *net = dev_net(skb_dst(skb)->dev); 724 725 memset(&rep.th, 0, sizeof(struct tcphdr)); 726 memset(&arg, 0, sizeof(arg)); 727 728 arg.iov[0].iov_base = (unsigned char *)&rep; 729 arg.iov[0].iov_len = sizeof(rep.th); 730 if (tsecr) { 731 rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 732 (TCPOPT_TIMESTAMP << 8) | 733 TCPOLEN_TIMESTAMP); 734 rep.opt[1] = htonl(tsval); 735 rep.opt[2] = htonl(tsecr); 736 arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; 737 } 738 739 /* Swap the send and the receive. */ 740 rep.th.dest = th->source; 741 rep.th.source = th->dest; 742 rep.th.doff = arg.iov[0].iov_len / 4; 743 rep.th.seq = htonl(seq); 744 rep.th.ack_seq = htonl(ack); 745 rep.th.ack = 1; 746 rep.th.window = htons(win); 747 748 #ifdef CONFIG_TCP_MD5SIG 749 if (key) { 750 int offset = (tsecr) ? 3 : 0; 751 752 rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | 753 (TCPOPT_NOP << 16) | 754 (TCPOPT_MD5SIG << 8) | 755 TCPOLEN_MD5SIG); 756 arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; 757 rep.th.doff = arg.iov[0].iov_len/4; 758 759 tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], 760 key, ip_hdr(skb)->saddr, 761 ip_hdr(skb)->daddr, &rep.th); 762 } 763 #endif 764 arg.flags = reply_flags; 765 arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, 766 ip_hdr(skb)->saddr, /* XXX */ 767 arg.iov[0].iov_len, IPPROTO_TCP, 0); 768 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 769 if (oif) 770 arg.bound_dev_if = oif; 771 arg.tos = tos; 772 ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), 773 skb, &TCP_SKB_CB(skb)->header.h4.opt, 774 ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, 775 &arg, arg.iov[0].iov_len); 776 777 TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS); 778 } 779 780 static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 781 { 782 struct inet_timewait_sock *tw = inet_twsk(sk); 783 struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 784 785 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 786 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, 787 tcp_time_stamp + tcptw->tw_ts_offset, 788 tcptw->tw_ts_recent, 789 tw->tw_bound_dev_if, 790 tcp_twsk_md5_key(tcptw), 791 tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, 792 tw->tw_tos 793 ); 794 795 inet_twsk_put(tw); 796 } 797 798 static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 799 struct request_sock *req) 800 { 801 /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV 802 * sk->sk_state == TCP_SYN_RECV -> for Fast Open. 803 */ 804 tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ? 805 tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, 806 tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd, 807 tcp_time_stamp, 808 req->ts_recent, 809 0, 810 tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr, 811 AF_INET), 812 inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, 813 ip_hdr(skb)->tos); 814 } 815 816 /* 817 * Send a SYN-ACK after having received a SYN. 818 * This still operates on a request_sock only, not on a big 819 * socket. 820 */ 821 static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, 822 struct flowi *fl, 823 struct request_sock *req, 824 struct tcp_fastopen_cookie *foc, 825 bool attach_req) 826 { 827 const struct inet_request_sock *ireq = inet_rsk(req); 828 struct flowi4 fl4; 829 int err = -1; 830 struct sk_buff *skb; 831 832 /* First, grab a route. */ 833 if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) 834 return -1; 835 836 skb = tcp_make_synack(sk, dst, req, foc, attach_req); 837 838 if (skb) { 839 __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); 840 841 err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, 842 ireq->ir_rmt_addr, 843 ireq->opt); 844 err = net_xmit_eval(err); 845 } 846 847 return err; 848 } 849 850 /* 851 * IPv4 request_sock destructor. 852 */ 853 static void tcp_v4_reqsk_destructor(struct request_sock *req) 854 { 855 kfree(inet_rsk(req)->opt); 856 } 857 858 859 #ifdef CONFIG_TCP_MD5SIG 860 /* 861 * RFC2385 MD5 checksumming requires a mapping of 862 * IP address->MD5 Key. 863 * We need to maintain these in the sk structure. 864 */ 865 866 /* Find the Key structure for an address. */ 867 struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk, 868 const union tcp_md5_addr *addr, 869 int family) 870 { 871 const struct tcp_sock *tp = tcp_sk(sk); 872 struct tcp_md5sig_key *key; 873 unsigned int size = sizeof(struct in_addr); 874 const struct tcp_md5sig_info *md5sig; 875 876 /* caller either holds rcu_read_lock() or socket lock */ 877 md5sig = rcu_dereference_check(tp->md5sig_info, 878 sock_owned_by_user(sk) || 879 lockdep_is_held((spinlock_t *)&sk->sk_lock.slock)); 880 if (!md5sig) 881 return NULL; 882 #if IS_ENABLED(CONFIG_IPV6) 883 if (family == AF_INET6) 884 size = sizeof(struct in6_addr); 885 #endif 886 hlist_for_each_entry_rcu(key, &md5sig->head, node) { 887 if (key->family != family) 888 continue; 889 if (!memcmp(&key->addr, addr, size)) 890 return key; 891 } 892 return NULL; 893 } 894 EXPORT_SYMBOL(tcp_md5_do_lookup); 895 896 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, 897 const struct sock *addr_sk) 898 { 899 const union tcp_md5_addr *addr; 900 901 addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr; 902 return tcp_md5_do_lookup(sk, addr, AF_INET); 903 } 904 EXPORT_SYMBOL(tcp_v4_md5_lookup); 905 906 /* This can be called on a newly created socket, from other files */ 907 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 908 int family, const u8 *newkey, u8 newkeylen, gfp_t gfp) 909 { 910 /* Add Key to the list */ 911 struct tcp_md5sig_key *key; 912 struct tcp_sock *tp = tcp_sk(sk); 913 struct tcp_md5sig_info *md5sig; 914 915 key = tcp_md5_do_lookup(sk, addr, family); 916 if (key) { 917 /* Pre-existing entry - just update that one. */ 918 memcpy(key->key, newkey, newkeylen); 919 key->keylen = newkeylen; 920 return 0; 921 } 922 923 md5sig = rcu_dereference_protected(tp->md5sig_info, 924 sock_owned_by_user(sk) || 925 lockdep_is_held(&sk->sk_lock.slock)); 926 if (!md5sig) { 927 md5sig = kmalloc(sizeof(*md5sig), gfp); 928 if (!md5sig) 929 return -ENOMEM; 930 931 sk_nocaps_add(sk, NETIF_F_GSO_MASK); 932 INIT_HLIST_HEAD(&md5sig->head); 933 rcu_assign_pointer(tp->md5sig_info, md5sig); 934 } 935 936 key = sock_kmalloc(sk, sizeof(*key), gfp); 937 if (!key) 938 return -ENOMEM; 939 if (!tcp_alloc_md5sig_pool()) { 940 sock_kfree_s(sk, key, sizeof(*key)); 941 return -ENOMEM; 942 } 943 944 memcpy(key->key, newkey, newkeylen); 945 key->keylen = newkeylen; 946 key->family = family; 947 memcpy(&key->addr, addr, 948 (family == AF_INET6) ? sizeof(struct in6_addr) : 949 sizeof(struct in_addr)); 950 hlist_add_head_rcu(&key->node, &md5sig->head); 951 return 0; 952 } 953 EXPORT_SYMBOL(tcp_md5_do_add); 954 955 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family) 956 { 957 struct tcp_md5sig_key *key; 958 959 key = tcp_md5_do_lookup(sk, addr, family); 960 if (!key) 961 return -ENOENT; 962 hlist_del_rcu(&key->node); 963 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 964 kfree_rcu(key, rcu); 965 return 0; 966 } 967 EXPORT_SYMBOL(tcp_md5_do_del); 968 969 static void tcp_clear_md5_list(struct sock *sk) 970 { 971 struct tcp_sock *tp = tcp_sk(sk); 972 struct tcp_md5sig_key *key; 973 struct hlist_node *n; 974 struct tcp_md5sig_info *md5sig; 975 976 md5sig = rcu_dereference_protected(tp->md5sig_info, 1); 977 978 hlist_for_each_entry_safe(key, n, &md5sig->head, node) { 979 hlist_del_rcu(&key->node); 980 atomic_sub(sizeof(*key), &sk->sk_omem_alloc); 981 kfree_rcu(key, rcu); 982 } 983 } 984 985 static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval, 986 int optlen) 987 { 988 struct tcp_md5sig cmd; 989 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; 990 991 if (optlen < sizeof(cmd)) 992 return -EINVAL; 993 994 if (copy_from_user(&cmd, optval, sizeof(cmd))) 995 return -EFAULT; 996 997 if (sin->sin_family != AF_INET) 998 return -EINVAL; 999 1000 if (!cmd.tcpm_keylen) 1001 return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, 1002 AF_INET); 1003 1004 if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) 1005 return -EINVAL; 1006 1007 return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, 1008 AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, 1009 GFP_KERNEL); 1010 } 1011 1012 static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp, 1013 __be32 daddr, __be32 saddr, int nbytes) 1014 { 1015 struct tcp4_pseudohdr *bp; 1016 struct scatterlist sg; 1017 1018 bp = &hp->md5_blk.ip4; 1019 1020 /* 1021 * 1. the TCP pseudo-header (in the order: source IP address, 1022 * destination IP address, zero-padded protocol number, and 1023 * segment length) 1024 */ 1025 bp->saddr = saddr; 1026 bp->daddr = daddr; 1027 bp->pad = 0; 1028 bp->protocol = IPPROTO_TCP; 1029 bp->len = cpu_to_be16(nbytes); 1030 1031 sg_init_one(&sg, bp, sizeof(*bp)); 1032 return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp)); 1033 } 1034 1035 static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, 1036 __be32 daddr, __be32 saddr, const struct tcphdr *th) 1037 { 1038 struct tcp_md5sig_pool *hp; 1039 struct hash_desc *desc; 1040 1041 hp = tcp_get_md5sig_pool(); 1042 if (!hp) 1043 goto clear_hash_noput; 1044 desc = &hp->md5_desc; 1045 1046 if (crypto_hash_init(desc)) 1047 goto clear_hash; 1048 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2)) 1049 goto clear_hash; 1050 if (tcp_md5_hash_header(hp, th)) 1051 goto clear_hash; 1052 if (tcp_md5_hash_key(hp, key)) 1053 goto clear_hash; 1054 if (crypto_hash_final(desc, md5_hash)) 1055 goto clear_hash; 1056 1057 tcp_put_md5sig_pool(); 1058 return 0; 1059 1060 clear_hash: 1061 tcp_put_md5sig_pool(); 1062 clear_hash_noput: 1063 memset(md5_hash, 0, 16); 1064 return 1; 1065 } 1066 1067 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, 1068 const struct sock *sk, 1069 const struct sk_buff *skb) 1070 { 1071 struct tcp_md5sig_pool *hp; 1072 struct hash_desc *desc; 1073 const struct tcphdr *th = tcp_hdr(skb); 1074 __be32 saddr, daddr; 1075 1076 if (sk) { /* valid for establish/request sockets */ 1077 saddr = sk->sk_rcv_saddr; 1078 daddr = sk->sk_daddr; 1079 } else { 1080 const struct iphdr *iph = ip_hdr(skb); 1081 saddr = iph->saddr; 1082 daddr = iph->daddr; 1083 } 1084 1085 hp = tcp_get_md5sig_pool(); 1086 if (!hp) 1087 goto clear_hash_noput; 1088 desc = &hp->md5_desc; 1089 1090 if (crypto_hash_init(desc)) 1091 goto clear_hash; 1092 1093 if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len)) 1094 goto clear_hash; 1095 if (tcp_md5_hash_header(hp, th)) 1096 goto clear_hash; 1097 if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) 1098 goto clear_hash; 1099 if (tcp_md5_hash_key(hp, key)) 1100 goto clear_hash; 1101 if (crypto_hash_final(desc, md5_hash)) 1102 goto clear_hash; 1103 1104 tcp_put_md5sig_pool(); 1105 return 0; 1106 1107 clear_hash: 1108 tcp_put_md5sig_pool(); 1109 clear_hash_noput: 1110 memset(md5_hash, 0, 16); 1111 return 1; 1112 } 1113 EXPORT_SYMBOL(tcp_v4_md5_hash_skb); 1114 1115 #endif 1116 1117 /* Called with rcu_read_lock() */ 1118 static bool tcp_v4_inbound_md5_hash(const struct sock *sk, 1119 const struct sk_buff *skb) 1120 { 1121 #ifdef CONFIG_TCP_MD5SIG 1122 /* 1123 * This gets called for each TCP segment that arrives 1124 * so we want to be efficient. 1125 * We have 3 drop cases: 1126 * o No MD5 hash and one expected. 1127 * o MD5 hash and we're not expecting one. 1128 * o MD5 hash and its wrong. 1129 */ 1130 const __u8 *hash_location = NULL; 1131 struct tcp_md5sig_key *hash_expected; 1132 const struct iphdr *iph = ip_hdr(skb); 1133 const struct tcphdr *th = tcp_hdr(skb); 1134 int genhash; 1135 unsigned char newhash[16]; 1136 1137 hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr, 1138 AF_INET); 1139 hash_location = tcp_parse_md5sig_option(th); 1140 1141 /* We've parsed the options - do we have a hash? */ 1142 if (!hash_expected && !hash_location) 1143 return false; 1144 1145 if (hash_expected && !hash_location) { 1146 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); 1147 return true; 1148 } 1149 1150 if (!hash_expected && hash_location) { 1151 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); 1152 return true; 1153 } 1154 1155 /* Okay, so this is hash_expected and hash_location - 1156 * so we need to calculate the checksum. 1157 */ 1158 genhash = tcp_v4_md5_hash_skb(newhash, 1159 hash_expected, 1160 NULL, skb); 1161 1162 if (genhash || memcmp(hash_location, newhash, 16) != 0) { 1163 net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n", 1164 &iph->saddr, ntohs(th->source), 1165 &iph->daddr, ntohs(th->dest), 1166 genhash ? " tcp_v4_calc_md5_hash failed" 1167 : ""); 1168 return true; 1169 } 1170 return false; 1171 #endif 1172 return false; 1173 } 1174 1175 static void tcp_v4_init_req(struct request_sock *req, 1176 const struct sock *sk_listener, 1177 struct sk_buff *skb) 1178 { 1179 struct inet_request_sock *ireq = inet_rsk(req); 1180 1181 sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr); 1182 sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr); 1183 ireq->no_srccheck = inet_sk(sk_listener)->transparent; 1184 ireq->opt = tcp_v4_save_options(skb); 1185 } 1186 1187 static struct dst_entry *tcp_v4_route_req(const struct sock *sk, 1188 struct flowi *fl, 1189 const struct request_sock *req, 1190 bool *strict) 1191 { 1192 struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req); 1193 1194 if (strict) { 1195 if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr) 1196 *strict = true; 1197 else 1198 *strict = false; 1199 } 1200 1201 return dst; 1202 } 1203 1204 struct request_sock_ops tcp_request_sock_ops __read_mostly = { 1205 .family = PF_INET, 1206 .obj_size = sizeof(struct tcp_request_sock), 1207 .rtx_syn_ack = tcp_rtx_synack, 1208 .send_ack = tcp_v4_reqsk_send_ack, 1209 .destructor = tcp_v4_reqsk_destructor, 1210 .send_reset = tcp_v4_send_reset, 1211 .syn_ack_timeout = tcp_syn_ack_timeout, 1212 }; 1213 1214 static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { 1215 .mss_clamp = TCP_MSS_DEFAULT, 1216 #ifdef CONFIG_TCP_MD5SIG 1217 .req_md5_lookup = tcp_v4_md5_lookup, 1218 .calc_md5_hash = tcp_v4_md5_hash_skb, 1219 #endif 1220 .init_req = tcp_v4_init_req, 1221 #ifdef CONFIG_SYN_COOKIES 1222 .cookie_init_seq = cookie_v4_init_sequence, 1223 #endif 1224 .route_req = tcp_v4_route_req, 1225 .init_seq = tcp_v4_init_sequence, 1226 .send_synack = tcp_v4_send_synack, 1227 }; 1228 1229 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 1230 { 1231 /* Never answer to SYNs send to broadcast or multicast */ 1232 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) 1233 goto drop; 1234 1235 return tcp_conn_request(&tcp_request_sock_ops, 1236 &tcp_request_sock_ipv4_ops, sk, skb); 1237 1238 drop: 1239 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); 1240 return 0; 1241 } 1242 EXPORT_SYMBOL(tcp_v4_conn_request); 1243 1244 1245 /* 1246 * The three way handshake has completed - we got a valid synack - 1247 * now create the new socket. 1248 */ 1249 struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, 1250 struct request_sock *req, 1251 struct dst_entry *dst, 1252 struct request_sock *req_unhash, 1253 bool *own_req) 1254 { 1255 struct inet_request_sock *ireq; 1256 struct inet_sock *newinet; 1257 struct tcp_sock *newtp; 1258 struct sock *newsk; 1259 #ifdef CONFIG_TCP_MD5SIG 1260 struct tcp_md5sig_key *key; 1261 #endif 1262 struct ip_options_rcu *inet_opt; 1263 1264 if (sk_acceptq_is_full(sk)) 1265 goto exit_overflow; 1266 1267 newsk = tcp_create_openreq_child(sk, req, skb); 1268 if (!newsk) 1269 goto exit_nonewsk; 1270 1271 newsk->sk_gso_type = SKB_GSO_TCPV4; 1272 inet_sk_rx_dst_set(newsk, skb); 1273 1274 newtp = tcp_sk(newsk); 1275 newinet = inet_sk(newsk); 1276 ireq = inet_rsk(req); 1277 sk_daddr_set(newsk, ireq->ir_rmt_addr); 1278 sk_rcv_saddr_set(newsk, ireq->ir_loc_addr); 1279 newinet->inet_saddr = ireq->ir_loc_addr; 1280 inet_opt = ireq->opt; 1281 rcu_assign_pointer(newinet->inet_opt, inet_opt); 1282 ireq->opt = NULL; 1283 newinet->mc_index = inet_iif(skb); 1284 newinet->mc_ttl = ip_hdr(skb)->ttl; 1285 newinet->rcv_tos = ip_hdr(skb)->tos; 1286 inet_csk(newsk)->icsk_ext_hdr_len = 0; 1287 if (inet_opt) 1288 inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; 1289 newinet->inet_id = newtp->write_seq ^ jiffies; 1290 1291 if (!dst) { 1292 dst = inet_csk_route_child_sock(sk, newsk, req); 1293 if (!dst) 1294 goto put_and_exit; 1295 } else { 1296 /* syncookie case : see end of cookie_v4_check() */ 1297 } 1298 sk_setup_caps(newsk, dst); 1299 1300 tcp_ca_openreq_child(newsk, dst); 1301 1302 tcp_sync_mss(newsk, dst_mtu(dst)); 1303 newtp->advmss = dst_metric_advmss(dst); 1304 if (tcp_sk(sk)->rx_opt.user_mss && 1305 tcp_sk(sk)->rx_opt.user_mss < newtp->advmss) 1306 newtp->advmss = tcp_sk(sk)->rx_opt.user_mss; 1307 1308 tcp_initialize_rcv_mss(newsk); 1309 1310 #ifdef CONFIG_TCP_MD5SIG 1311 /* Copy over the MD5 key from the original socket */ 1312 key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr, 1313 AF_INET); 1314 if (key) { 1315 /* 1316 * We're using one, so create a matching key 1317 * on the newsk structure. If we fail to get 1318 * memory, then we end up not copying the key 1319 * across. Shucks. 1320 */ 1321 tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr, 1322 AF_INET, key->key, key->keylen, GFP_ATOMIC); 1323 sk_nocaps_add(newsk, NETIF_F_GSO_MASK); 1324 } 1325 #endif 1326 1327 if (__inet_inherit_port(sk, newsk) < 0) 1328 goto put_and_exit; 1329 *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); 1330 if (*own_req) 1331 tcp_move_syn(newtp, req); 1332 1333 return newsk; 1334 1335 exit_overflow: 1336 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); 1337 exit_nonewsk: 1338 dst_release(dst); 1339 exit: 1340 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); 1341 return NULL; 1342 put_and_exit: 1343 inet_csk_prepare_forced_close(newsk); 1344 tcp_done(newsk); 1345 goto exit; 1346 } 1347 EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 1348 1349 static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb) 1350 { 1351 #ifdef CONFIG_SYN_COOKIES 1352 const struct tcphdr *th = tcp_hdr(skb); 1353 1354 if (!th->syn) 1355 sk = cookie_v4_check(sk, skb); 1356 #endif 1357 return sk; 1358 } 1359 1360 /* The socket must have it's spinlock held when we get 1361 * here, unless it is a TCP_LISTEN socket. 1362 * 1363 * We have a potential double-lock case here, so even when 1364 * doing backlog processing we use the BH locking scheme. 1365 * This is because we cannot sleep with the original spinlock 1366 * held. 1367 */ 1368 int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1369 { 1370 struct sock *rsk; 1371 1372 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1373 struct dst_entry *dst = sk->sk_rx_dst; 1374 1375 sock_rps_save_rxhash(sk, skb); 1376 sk_mark_napi_id(sk, skb); 1377 if (dst) { 1378 if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif || 1379 !dst->ops->check(dst, 0)) { 1380 dst_release(dst); 1381 sk->sk_rx_dst = NULL; 1382 } 1383 } 1384 tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len); 1385 return 0; 1386 } 1387 1388 if (tcp_checksum_complete(skb)) 1389 goto csum_err; 1390 1391 if (sk->sk_state == TCP_LISTEN) { 1392 struct sock *nsk = tcp_v4_cookie_check(sk, skb); 1393 1394 if (!nsk) 1395 goto discard; 1396 if (nsk != sk) { 1397 sock_rps_save_rxhash(nsk, skb); 1398 sk_mark_napi_id(nsk, skb); 1399 if (tcp_child_process(sk, nsk, skb)) { 1400 rsk = nsk; 1401 goto reset; 1402 } 1403 return 0; 1404 } 1405 } else 1406 sock_rps_save_rxhash(sk, skb); 1407 1408 if (tcp_rcv_state_process(sk, skb)) { 1409 rsk = sk; 1410 goto reset; 1411 } 1412 return 0; 1413 1414 reset: 1415 tcp_v4_send_reset(rsk, skb); 1416 discard: 1417 kfree_skb(skb); 1418 /* Be careful here. If this function gets more complicated and 1419 * gcc suffers from register pressure on the x86, sk (in %ebx) 1420 * might be destroyed here. This current version compiles correctly, 1421 * but you have been warned. 1422 */ 1423 return 0; 1424 1425 csum_err: 1426 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS); 1427 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); 1428 goto discard; 1429 } 1430 EXPORT_SYMBOL(tcp_v4_do_rcv); 1431 1432 void tcp_v4_early_demux(struct sk_buff *skb) 1433 { 1434 const struct iphdr *iph; 1435 const struct tcphdr *th; 1436 struct sock *sk; 1437 1438 if (skb->pkt_type != PACKET_HOST) 1439 return; 1440 1441 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) 1442 return; 1443 1444 iph = ip_hdr(skb); 1445 th = tcp_hdr(skb); 1446 1447 if (th->doff < sizeof(struct tcphdr) / 4) 1448 return; 1449 1450 sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo, 1451 iph->saddr, th->source, 1452 iph->daddr, ntohs(th->dest), 1453 skb->skb_iif); 1454 if (sk) { 1455 skb->sk = sk; 1456 skb->destructor = sock_edemux; 1457 if (sk_fullsock(sk)) { 1458 struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); 1459 1460 if (dst) 1461 dst = dst_check(dst, 0); 1462 if (dst && 1463 inet_sk(sk)->rx_dst_ifindex == skb->skb_iif) 1464 skb_dst_set_noref(skb, dst); 1465 } 1466 } 1467 } 1468 1469 /* Packet is added to VJ-style prequeue for processing in process 1470 * context, if a reader task is waiting. Apparently, this exciting 1471 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 1472 * failed somewhere. Latency? Burstiness? Well, at least now we will 1473 * see, why it failed. 8)8) --ANK 1474 * 1475 */ 1476 bool tcp_prequeue(struct sock *sk, struct sk_buff *skb) 1477 { 1478 struct tcp_sock *tp = tcp_sk(sk); 1479 1480 if (sysctl_tcp_low_latency || !tp->ucopy.task) 1481 return false; 1482 1483 if (skb->len <= tcp_hdrlen(skb) && 1484 skb_queue_len(&tp->ucopy.prequeue) == 0) 1485 return false; 1486 1487 /* Before escaping RCU protected region, we need to take care of skb 1488 * dst. Prequeue is only enabled for established sockets. 1489 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst 1490 * Instead of doing full sk_rx_dst validity here, let's perform 1491 * an optimistic check. 1492 */ 1493 if (likely(sk->sk_rx_dst)) 1494 skb_dst_drop(skb); 1495 else 1496 skb_dst_force(skb); 1497 1498 __skb_queue_tail(&tp->ucopy.prequeue, skb); 1499 tp->ucopy.memory += skb->truesize; 1500 if (tp->ucopy.memory > sk->sk_rcvbuf) { 1501 struct sk_buff *skb1; 1502 1503 BUG_ON(sock_owned_by_user(sk)); 1504 1505 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 1506 sk_backlog_rcv(sk, skb1); 1507 NET_INC_STATS_BH(sock_net(sk), 1508 LINUX_MIB_TCPPREQUEUEDROPPED); 1509 } 1510 1511 tp->ucopy.memory = 0; 1512 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 1513 wake_up_interruptible_sync_poll(sk_sleep(sk), 1514 POLLIN | POLLRDNORM | POLLRDBAND); 1515 if (!inet_csk_ack_scheduled(sk)) 1516 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 1517 (3 * tcp_rto_min(sk)) / 4, 1518 TCP_RTO_MAX); 1519 } 1520 return true; 1521 } 1522 EXPORT_SYMBOL(tcp_prequeue); 1523 1524 /* 1525 * From tcp_input.c 1526 */ 1527 1528 int tcp_v4_rcv(struct sk_buff *skb) 1529 { 1530 const struct iphdr *iph; 1531 const struct tcphdr *th; 1532 struct sock *sk; 1533 int ret; 1534 struct net *net = dev_net(skb->dev); 1535 1536 if (skb->pkt_type != PACKET_HOST) 1537 goto discard_it; 1538 1539 /* Count it even if it's bad */ 1540 TCP_INC_STATS_BH(net, TCP_MIB_INSEGS); 1541 1542 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 1543 goto discard_it; 1544 1545 th = tcp_hdr(skb); 1546 1547 if (th->doff < sizeof(struct tcphdr) / 4) 1548 goto bad_packet; 1549 if (!pskb_may_pull(skb, th->doff * 4)) 1550 goto discard_it; 1551 1552 /* An explanation is required here, I think. 1553 * Packet length and doff are validated by header prediction, 1554 * provided case of th->doff==0 is eliminated. 1555 * So, we defer the checks. */ 1556 1557 if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo)) 1558 goto csum_error; 1559 1560 th = tcp_hdr(skb); 1561 iph = ip_hdr(skb); 1562 /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB() 1563 * barrier() makes sure compiler wont play fool^Waliasing games. 1564 */ 1565 memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb), 1566 sizeof(struct inet_skb_parm)); 1567 barrier(); 1568 1569 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 1570 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 1571 skb->len - th->doff * 4); 1572 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 1573 TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); 1574 TCP_SKB_CB(skb)->tcp_tw_isn = 0; 1575 TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); 1576 TCP_SKB_CB(skb)->sacked = 0; 1577 1578 lookup: 1579 sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest); 1580 if (!sk) 1581 goto no_tcp_socket; 1582 1583 process: 1584 if (sk->sk_state == TCP_TIME_WAIT) 1585 goto do_time_wait; 1586 1587 if (sk->sk_state == TCP_NEW_SYN_RECV) { 1588 struct request_sock *req = inet_reqsk(sk); 1589 struct sock *nsk = NULL; 1590 1591 sk = req->rsk_listener; 1592 if (tcp_v4_inbound_md5_hash(sk, skb)) 1593 goto discard_and_relse; 1594 if (likely(sk->sk_state == TCP_LISTEN)) { 1595 nsk = tcp_check_req(sk, skb, req, false); 1596 } else { 1597 inet_csk_reqsk_queue_drop_and_put(sk, req); 1598 goto lookup; 1599 } 1600 if (!nsk) { 1601 reqsk_put(req); 1602 goto discard_it; 1603 } 1604 if (nsk == sk) { 1605 sock_hold(sk); 1606 reqsk_put(req); 1607 } else if (tcp_child_process(sk, nsk, skb)) { 1608 tcp_v4_send_reset(nsk, skb); 1609 goto discard_it; 1610 } else { 1611 return 0; 1612 } 1613 } 1614 if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { 1615 NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP); 1616 goto discard_and_relse; 1617 } 1618 1619 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 1620 goto discard_and_relse; 1621 1622 if (tcp_v4_inbound_md5_hash(sk, skb)) 1623 goto discard_and_relse; 1624 1625 nf_reset(skb); 1626 1627 if (sk_filter(sk, skb)) 1628 goto discard_and_relse; 1629 1630 skb->dev = NULL; 1631 1632 if (sk->sk_state == TCP_LISTEN) { 1633 ret = tcp_v4_do_rcv(sk, skb); 1634 goto put_and_return; 1635 } 1636 1637 sk_incoming_cpu_update(sk); 1638 1639 bh_lock_sock_nested(sk); 1640 tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs); 1641 ret = 0; 1642 if (!sock_owned_by_user(sk)) { 1643 if (!tcp_prequeue(sk, skb)) 1644 ret = tcp_v4_do_rcv(sk, skb); 1645 } else if (unlikely(sk_add_backlog(sk, skb, 1646 sk->sk_rcvbuf + sk->sk_sndbuf))) { 1647 bh_unlock_sock(sk); 1648 NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP); 1649 goto discard_and_relse; 1650 } 1651 bh_unlock_sock(sk); 1652 1653 put_and_return: 1654 sock_put(sk); 1655 1656 return ret; 1657 1658 no_tcp_socket: 1659 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 1660 goto discard_it; 1661 1662 if (tcp_checksum_complete(skb)) { 1663 csum_error: 1664 TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS); 1665 bad_packet: 1666 TCP_INC_STATS_BH(net, TCP_MIB_INERRS); 1667 } else { 1668 tcp_v4_send_reset(NULL, skb); 1669 } 1670 1671 discard_it: 1672 /* Discard frame. */ 1673 kfree_skb(skb); 1674 return 0; 1675 1676 discard_and_relse: 1677 sock_put(sk); 1678 goto discard_it; 1679 1680 do_time_wait: 1681 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 1682 inet_twsk_put(inet_twsk(sk)); 1683 goto discard_it; 1684 } 1685 1686 if (tcp_checksum_complete(skb)) { 1687 inet_twsk_put(inet_twsk(sk)); 1688 goto csum_error; 1689 } 1690 switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { 1691 case TCP_TW_SYN: { 1692 struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev), 1693 &tcp_hashinfo, 1694 iph->saddr, th->source, 1695 iph->daddr, th->dest, 1696 inet_iif(skb)); 1697 if (sk2) { 1698 inet_twsk_deschedule_put(inet_twsk(sk)); 1699 sk = sk2; 1700 goto process; 1701 } 1702 /* Fall through to ACK */ 1703 } 1704 case TCP_TW_ACK: 1705 tcp_v4_timewait_ack(sk, skb); 1706 break; 1707 case TCP_TW_RST: 1708 goto no_tcp_socket; 1709 case TCP_TW_SUCCESS:; 1710 } 1711 goto discard_it; 1712 } 1713 1714 static struct timewait_sock_ops tcp_timewait_sock_ops = { 1715 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 1716 .twsk_unique = tcp_twsk_unique, 1717 .twsk_destructor= tcp_twsk_destructor, 1718 }; 1719 1720 void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 1721 { 1722 struct dst_entry *dst = skb_dst(skb); 1723 1724 if (dst) { 1725 dst_hold(dst); 1726 sk->sk_rx_dst = dst; 1727 inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; 1728 } 1729 } 1730 EXPORT_SYMBOL(inet_sk_rx_dst_set); 1731 1732 const struct inet_connection_sock_af_ops ipv4_specific = { 1733 .queue_xmit = ip_queue_xmit, 1734 .send_check = tcp_v4_send_check, 1735 .rebuild_header = inet_sk_rebuild_header, 1736 .sk_rx_dst_set = inet_sk_rx_dst_set, 1737 .conn_request = tcp_v4_conn_request, 1738 .syn_recv_sock = tcp_v4_syn_recv_sock, 1739 .net_header_len = sizeof(struct iphdr), 1740 .setsockopt = ip_setsockopt, 1741 .getsockopt = ip_getsockopt, 1742 .addr2sockaddr = inet_csk_addr2sockaddr, 1743 .sockaddr_len = sizeof(struct sockaddr_in), 1744 .bind_conflict = inet_csk_bind_conflict, 1745 #ifdef CONFIG_COMPAT 1746 .compat_setsockopt = compat_ip_setsockopt, 1747 .compat_getsockopt = compat_ip_getsockopt, 1748 #endif 1749 .mtu_reduced = tcp_v4_mtu_reduced, 1750 }; 1751 EXPORT_SYMBOL(ipv4_specific); 1752 1753 #ifdef CONFIG_TCP_MD5SIG 1754 static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { 1755 .md5_lookup = tcp_v4_md5_lookup, 1756 .calc_md5_hash = tcp_v4_md5_hash_skb, 1757 .md5_parse = tcp_v4_parse_md5_keys, 1758 }; 1759 #endif 1760 1761 /* NOTE: A lot of things set to zero explicitly by call to 1762 * sk_alloc() so need not be done here. 1763 */ 1764 static int tcp_v4_init_sock(struct sock *sk) 1765 { 1766 struct inet_connection_sock *icsk = inet_csk(sk); 1767 1768 tcp_init_sock(sk); 1769 1770 icsk->icsk_af_ops = &ipv4_specific; 1771 1772 #ifdef CONFIG_TCP_MD5SIG 1773 tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific; 1774 #endif 1775 1776 return 0; 1777 } 1778 1779 void tcp_v4_destroy_sock(struct sock *sk) 1780 { 1781 struct tcp_sock *tp = tcp_sk(sk); 1782 1783 tcp_clear_xmit_timers(sk); 1784 1785 tcp_cleanup_congestion_control(sk); 1786 1787 /* Cleanup up the write buffer. */ 1788 tcp_write_queue_purge(sk); 1789 1790 /* Cleans up our, hopefully empty, out_of_order_queue. */ 1791 __skb_queue_purge(&tp->out_of_order_queue); 1792 1793 #ifdef CONFIG_TCP_MD5SIG 1794 /* Clean up the MD5 key list, if any */ 1795 if (tp->md5sig_info) { 1796 tcp_clear_md5_list(sk); 1797 kfree_rcu(tp->md5sig_info, rcu); 1798 tp->md5sig_info = NULL; 1799 } 1800 #endif 1801 1802 /* Clean prequeue, it must be empty really */ 1803 __skb_queue_purge(&tp->ucopy.prequeue); 1804 1805 /* Clean up a referenced TCP bind bucket. */ 1806 if (inet_csk(sk)->icsk_bind_hash) 1807 inet_put_port(sk); 1808 1809 BUG_ON(tp->fastopen_rsk); 1810 1811 /* If socket is aborted during connect operation */ 1812 tcp_free_fastopen_req(tp); 1813 tcp_saved_syn_free(tp); 1814 1815 sk_sockets_allocated_dec(sk); 1816 sock_release_memcg(sk); 1817 } 1818 EXPORT_SYMBOL(tcp_v4_destroy_sock); 1819 1820 #ifdef CONFIG_PROC_FS 1821 /* Proc filesystem TCP sock list dumping. */ 1822 1823 /* 1824 * Get next listener socket follow cur. If cur is NULL, get first socket 1825 * starting from bucket given in st->bucket; when st->bucket is zero the 1826 * very first socket in the hash table is returned. 1827 */ 1828 static void *listening_get_next(struct seq_file *seq, void *cur) 1829 { 1830 struct inet_connection_sock *icsk; 1831 struct hlist_nulls_node *node; 1832 struct sock *sk = cur; 1833 struct inet_listen_hashbucket *ilb; 1834 struct tcp_iter_state *st = seq->private; 1835 struct net *net = seq_file_net(seq); 1836 1837 if (!sk) { 1838 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1839 spin_lock_bh(&ilb->lock); 1840 sk = sk_nulls_head(&ilb->head); 1841 st->offset = 0; 1842 goto get_sk; 1843 } 1844 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1845 ++st->num; 1846 ++st->offset; 1847 1848 sk = sk_nulls_next(sk); 1849 get_sk: 1850 sk_nulls_for_each_from(sk, node) { 1851 if (!net_eq(sock_net(sk), net)) 1852 continue; 1853 if (sk->sk_family == st->family) { 1854 cur = sk; 1855 goto out; 1856 } 1857 icsk = inet_csk(sk); 1858 } 1859 spin_unlock_bh(&ilb->lock); 1860 st->offset = 0; 1861 if (++st->bucket < INET_LHTABLE_SIZE) { 1862 ilb = &tcp_hashinfo.listening_hash[st->bucket]; 1863 spin_lock_bh(&ilb->lock); 1864 sk = sk_nulls_head(&ilb->head); 1865 goto get_sk; 1866 } 1867 cur = NULL; 1868 out: 1869 return cur; 1870 } 1871 1872 static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 1873 { 1874 struct tcp_iter_state *st = seq->private; 1875 void *rc; 1876 1877 st->bucket = 0; 1878 st->offset = 0; 1879 rc = listening_get_next(seq, NULL); 1880 1881 while (rc && *pos) { 1882 rc = listening_get_next(seq, rc); 1883 --*pos; 1884 } 1885 return rc; 1886 } 1887 1888 static inline bool empty_bucket(const struct tcp_iter_state *st) 1889 { 1890 return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain); 1891 } 1892 1893 /* 1894 * Get first established socket starting from bucket given in st->bucket. 1895 * If st->bucket is zero, the very first socket in the hash is returned. 1896 */ 1897 static void *established_get_first(struct seq_file *seq) 1898 { 1899 struct tcp_iter_state *st = seq->private; 1900 struct net *net = seq_file_net(seq); 1901 void *rc = NULL; 1902 1903 st->offset = 0; 1904 for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) { 1905 struct sock *sk; 1906 struct hlist_nulls_node *node; 1907 spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket); 1908 1909 /* Lockless fast path for the common case of empty buckets */ 1910 if (empty_bucket(st)) 1911 continue; 1912 1913 spin_lock_bh(lock); 1914 sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { 1915 if (sk->sk_family != st->family || 1916 !net_eq(sock_net(sk), net)) { 1917 continue; 1918 } 1919 rc = sk; 1920 goto out; 1921 } 1922 spin_unlock_bh(lock); 1923 } 1924 out: 1925 return rc; 1926 } 1927 1928 static void *established_get_next(struct seq_file *seq, void *cur) 1929 { 1930 struct sock *sk = cur; 1931 struct hlist_nulls_node *node; 1932 struct tcp_iter_state *st = seq->private; 1933 struct net *net = seq_file_net(seq); 1934 1935 ++st->num; 1936 ++st->offset; 1937 1938 sk = sk_nulls_next(sk); 1939 1940 sk_nulls_for_each_from(sk, node) { 1941 if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) 1942 return sk; 1943 } 1944 1945 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); 1946 ++st->bucket; 1947 return established_get_first(seq); 1948 } 1949 1950 static void *established_get_idx(struct seq_file *seq, loff_t pos) 1951 { 1952 struct tcp_iter_state *st = seq->private; 1953 void *rc; 1954 1955 st->bucket = 0; 1956 rc = established_get_first(seq); 1957 1958 while (rc && pos) { 1959 rc = established_get_next(seq, rc); 1960 --pos; 1961 } 1962 return rc; 1963 } 1964 1965 static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 1966 { 1967 void *rc; 1968 struct tcp_iter_state *st = seq->private; 1969 1970 st->state = TCP_SEQ_STATE_LISTENING; 1971 rc = listening_get_idx(seq, &pos); 1972 1973 if (!rc) { 1974 st->state = TCP_SEQ_STATE_ESTABLISHED; 1975 rc = established_get_idx(seq, pos); 1976 } 1977 1978 return rc; 1979 } 1980 1981 static void *tcp_seek_last_pos(struct seq_file *seq) 1982 { 1983 struct tcp_iter_state *st = seq->private; 1984 int offset = st->offset; 1985 int orig_num = st->num; 1986 void *rc = NULL; 1987 1988 switch (st->state) { 1989 case TCP_SEQ_STATE_LISTENING: 1990 if (st->bucket >= INET_LHTABLE_SIZE) 1991 break; 1992 st->state = TCP_SEQ_STATE_LISTENING; 1993 rc = listening_get_next(seq, NULL); 1994 while (offset-- && rc) 1995 rc = listening_get_next(seq, rc); 1996 if (rc) 1997 break; 1998 st->bucket = 0; 1999 st->state = TCP_SEQ_STATE_ESTABLISHED; 2000 /* Fallthrough */ 2001 case TCP_SEQ_STATE_ESTABLISHED: 2002 if (st->bucket > tcp_hashinfo.ehash_mask) 2003 break; 2004 rc = established_get_first(seq); 2005 while (offset-- && rc) 2006 rc = established_get_next(seq, rc); 2007 } 2008 2009 st->num = orig_num; 2010 2011 return rc; 2012 } 2013 2014 static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 2015 { 2016 struct tcp_iter_state *st = seq->private; 2017 void *rc; 2018 2019 if (*pos && *pos == st->last_pos) { 2020 rc = tcp_seek_last_pos(seq); 2021 if (rc) 2022 goto out; 2023 } 2024 2025 st->state = TCP_SEQ_STATE_LISTENING; 2026 st->num = 0; 2027 st->bucket = 0; 2028 st->offset = 0; 2029 rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 2030 2031 out: 2032 st->last_pos = *pos; 2033 return rc; 2034 } 2035 2036 static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2037 { 2038 struct tcp_iter_state *st = seq->private; 2039 void *rc = NULL; 2040 2041 if (v == SEQ_START_TOKEN) { 2042 rc = tcp_get_idx(seq, 0); 2043 goto out; 2044 } 2045 2046 switch (st->state) { 2047 case TCP_SEQ_STATE_LISTENING: 2048 rc = listening_get_next(seq, v); 2049 if (!rc) { 2050 st->state = TCP_SEQ_STATE_ESTABLISHED; 2051 st->bucket = 0; 2052 st->offset = 0; 2053 rc = established_get_first(seq); 2054 } 2055 break; 2056 case TCP_SEQ_STATE_ESTABLISHED: 2057 rc = established_get_next(seq, v); 2058 break; 2059 } 2060 out: 2061 ++*pos; 2062 st->last_pos = *pos; 2063 return rc; 2064 } 2065 2066 static void tcp_seq_stop(struct seq_file *seq, void *v) 2067 { 2068 struct tcp_iter_state *st = seq->private; 2069 2070 switch (st->state) { 2071 case TCP_SEQ_STATE_LISTENING: 2072 if (v != SEQ_START_TOKEN) 2073 spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock); 2074 break; 2075 case TCP_SEQ_STATE_ESTABLISHED: 2076 if (v) 2077 spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); 2078 break; 2079 } 2080 } 2081 2082 int tcp_seq_open(struct inode *inode, struct file *file) 2083 { 2084 struct tcp_seq_afinfo *afinfo = PDE_DATA(inode); 2085 struct tcp_iter_state *s; 2086 int err; 2087 2088 err = seq_open_net(inode, file, &afinfo->seq_ops, 2089 sizeof(struct tcp_iter_state)); 2090 if (err < 0) 2091 return err; 2092 2093 s = ((struct seq_file *)file->private_data)->private; 2094 s->family = afinfo->family; 2095 s->last_pos = 0; 2096 return 0; 2097 } 2098 EXPORT_SYMBOL(tcp_seq_open); 2099 2100 int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo) 2101 { 2102 int rc = 0; 2103 struct proc_dir_entry *p; 2104 2105 afinfo->seq_ops.start = tcp_seq_start; 2106 afinfo->seq_ops.next = tcp_seq_next; 2107 afinfo->seq_ops.stop = tcp_seq_stop; 2108 2109 p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net, 2110 afinfo->seq_fops, afinfo); 2111 if (!p) 2112 rc = -ENOMEM; 2113 return rc; 2114 } 2115 EXPORT_SYMBOL(tcp_proc_register); 2116 2117 void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo) 2118 { 2119 remove_proc_entry(afinfo->name, net->proc_net); 2120 } 2121 EXPORT_SYMBOL(tcp_proc_unregister); 2122 2123 static void get_openreq4(const struct request_sock *req, 2124 struct seq_file *f, int i) 2125 { 2126 const struct inet_request_sock *ireq = inet_rsk(req); 2127 long delta = req->rsk_timer.expires - jiffies; 2128 2129 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2130 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK", 2131 i, 2132 ireq->ir_loc_addr, 2133 ireq->ir_num, 2134 ireq->ir_rmt_addr, 2135 ntohs(ireq->ir_rmt_port), 2136 TCP_SYN_RECV, 2137 0, 0, /* could print option size, but that is af dependent. */ 2138 1, /* timers active (only the expire timer) */ 2139 jiffies_delta_to_clock_t(delta), 2140 req->num_timeout, 2141 from_kuid_munged(seq_user_ns(f), 2142 sock_i_uid(req->rsk_listener)), 2143 0, /* non standard timer */ 2144 0, /* open_requests have no inode */ 2145 0, 2146 req); 2147 } 2148 2149 static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) 2150 { 2151 int timer_active; 2152 unsigned long timer_expires; 2153 const struct tcp_sock *tp = tcp_sk(sk); 2154 const struct inet_connection_sock *icsk = inet_csk(sk); 2155 const struct inet_sock *inet = inet_sk(sk); 2156 const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; 2157 __be32 dest = inet->inet_daddr; 2158 __be32 src = inet->inet_rcv_saddr; 2159 __u16 destp = ntohs(inet->inet_dport); 2160 __u16 srcp = ntohs(inet->inet_sport); 2161 int rx_queue; 2162 int state; 2163 2164 if (icsk->icsk_pending == ICSK_TIME_RETRANS || 2165 icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS || 2166 icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { 2167 timer_active = 1; 2168 timer_expires = icsk->icsk_timeout; 2169 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 2170 timer_active = 4; 2171 timer_expires = icsk->icsk_timeout; 2172 } else if (timer_pending(&sk->sk_timer)) { 2173 timer_active = 2; 2174 timer_expires = sk->sk_timer.expires; 2175 } else { 2176 timer_active = 0; 2177 timer_expires = jiffies; 2178 } 2179 2180 state = sk_state_load(sk); 2181 if (state == TCP_LISTEN) 2182 rx_queue = sk->sk_ack_backlog; 2183 else 2184 /* Because we don't lock the socket, 2185 * we might find a transient negative value. 2186 */ 2187 rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0); 2188 2189 seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 2190 "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d", 2191 i, src, srcp, dest, destp, state, 2192 tp->write_seq - tp->snd_una, 2193 rx_queue, 2194 timer_active, 2195 jiffies_delta_to_clock_t(timer_expires - jiffies), 2196 icsk->icsk_retransmits, 2197 from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)), 2198 icsk->icsk_probes_out, 2199 sock_i_ino(sk), 2200 atomic_read(&sk->sk_refcnt), sk, 2201 jiffies_to_clock_t(icsk->icsk_rto), 2202 jiffies_to_clock_t(icsk->icsk_ack.ato), 2203 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, 2204 tp->snd_cwnd, 2205 state == TCP_LISTEN ? 2206 fastopenq->max_qlen : 2207 (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); 2208 } 2209 2210 static void get_timewait4_sock(const struct inet_timewait_sock *tw, 2211 struct seq_file *f, int i) 2212 { 2213 long delta = tw->tw_timer.expires - jiffies; 2214 __be32 dest, src; 2215 __u16 destp, srcp; 2216 2217 dest = tw->tw_daddr; 2218 src = tw->tw_rcv_saddr; 2219 destp = ntohs(tw->tw_dport); 2220 srcp = ntohs(tw->tw_sport); 2221 2222 seq_printf(f, "%4d: %08X:%04X %08X:%04X" 2223 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK", 2224 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 2225 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, 2226 atomic_read(&tw->tw_refcnt), tw); 2227 } 2228 2229 #define TMPSZ 150 2230 2231 static int tcp4_seq_show(struct seq_file *seq, void *v) 2232 { 2233 struct tcp_iter_state *st; 2234 struct sock *sk = v; 2235 2236 seq_setwidth(seq, TMPSZ - 1); 2237 if (v == SEQ_START_TOKEN) { 2238 seq_puts(seq, " sl local_address rem_address st tx_queue " 2239 "rx_queue tr tm->when retrnsmt uid timeout " 2240 "inode"); 2241 goto out; 2242 } 2243 st = seq->private; 2244 2245 if (sk->sk_state == TCP_TIME_WAIT) 2246 get_timewait4_sock(v, seq, st->num); 2247 else if (sk->sk_state == TCP_NEW_SYN_RECV) 2248 get_openreq4(v, seq, st->num); 2249 else 2250 get_tcp4_sock(v, seq, st->num); 2251 out: 2252 seq_pad(seq, '\n'); 2253 return 0; 2254 } 2255 2256 static const struct file_operations tcp_afinfo_seq_fops = { 2257 .owner = THIS_MODULE, 2258 .open = tcp_seq_open, 2259 .read = seq_read, 2260 .llseek = seq_lseek, 2261 .release = seq_release_net 2262 }; 2263 2264 static struct tcp_seq_afinfo tcp4_seq_afinfo = { 2265 .name = "tcp", 2266 .family = AF_INET, 2267 .seq_fops = &tcp_afinfo_seq_fops, 2268 .seq_ops = { 2269 .show = tcp4_seq_show, 2270 }, 2271 }; 2272 2273 static int __net_init tcp4_proc_init_net(struct net *net) 2274 { 2275 return tcp_proc_register(net, &tcp4_seq_afinfo); 2276 } 2277 2278 static void __net_exit tcp4_proc_exit_net(struct net *net) 2279 { 2280 tcp_proc_unregister(net, &tcp4_seq_afinfo); 2281 } 2282 2283 static struct pernet_operations tcp4_net_ops = { 2284 .init = tcp4_proc_init_net, 2285 .exit = tcp4_proc_exit_net, 2286 }; 2287 2288 int __init tcp4_proc_init(void) 2289 { 2290 return register_pernet_subsys(&tcp4_net_ops); 2291 } 2292 2293 void tcp4_proc_exit(void) 2294 { 2295 unregister_pernet_subsys(&tcp4_net_ops); 2296 } 2297 #endif /* CONFIG_PROC_FS */ 2298 2299 struct proto tcp_prot = { 2300 .name = "TCP", 2301 .owner = THIS_MODULE, 2302 .close = tcp_close, 2303 .connect = tcp_v4_connect, 2304 .disconnect = tcp_disconnect, 2305 .accept = inet_csk_accept, 2306 .ioctl = tcp_ioctl, 2307 .init = tcp_v4_init_sock, 2308 .destroy = tcp_v4_destroy_sock, 2309 .shutdown = tcp_shutdown, 2310 .setsockopt = tcp_setsockopt, 2311 .getsockopt = tcp_getsockopt, 2312 .recvmsg = tcp_recvmsg, 2313 .sendmsg = tcp_sendmsg, 2314 .sendpage = tcp_sendpage, 2315 .backlog_rcv = tcp_v4_do_rcv, 2316 .release_cb = tcp_release_cb, 2317 .hash = inet_hash, 2318 .unhash = inet_unhash, 2319 .get_port = inet_csk_get_port, 2320 .enter_memory_pressure = tcp_enter_memory_pressure, 2321 .stream_memory_free = tcp_stream_memory_free, 2322 .sockets_allocated = &tcp_sockets_allocated, 2323 .orphan_count = &tcp_orphan_count, 2324 .memory_allocated = &tcp_memory_allocated, 2325 .memory_pressure = &tcp_memory_pressure, 2326 .sysctl_mem = sysctl_tcp_mem, 2327 .sysctl_wmem = sysctl_tcp_wmem, 2328 .sysctl_rmem = sysctl_tcp_rmem, 2329 .max_header = MAX_TCP_HEADER, 2330 .obj_size = sizeof(struct tcp_sock), 2331 .slab_flags = SLAB_DESTROY_BY_RCU, 2332 .twsk_prot = &tcp_timewait_sock_ops, 2333 .rsk_prot = &tcp_request_sock_ops, 2334 .h.hashinfo = &tcp_hashinfo, 2335 .no_autobind = true, 2336 #ifdef CONFIG_COMPAT 2337 .compat_setsockopt = compat_tcp_setsockopt, 2338 .compat_getsockopt = compat_tcp_getsockopt, 2339 #endif 2340 #ifdef CONFIG_MEMCG_KMEM 2341 .init_cgroup = tcp_init_cgroup, 2342 .destroy_cgroup = tcp_destroy_cgroup, 2343 .proto_cgroup = tcp_proto_cgroup, 2344 #endif 2345 }; 2346 EXPORT_SYMBOL(tcp_prot); 2347 2348 static void __net_exit tcp_sk_exit(struct net *net) 2349 { 2350 int cpu; 2351 2352 for_each_possible_cpu(cpu) 2353 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu)); 2354 free_percpu(net->ipv4.tcp_sk); 2355 } 2356 2357 static int __net_init tcp_sk_init(struct net *net) 2358 { 2359 int res, cpu; 2360 2361 net->ipv4.tcp_sk = alloc_percpu(struct sock *); 2362 if (!net->ipv4.tcp_sk) 2363 return -ENOMEM; 2364 2365 for_each_possible_cpu(cpu) { 2366 struct sock *sk; 2367 2368 res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW, 2369 IPPROTO_TCP, net); 2370 if (res) 2371 goto fail; 2372 *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk; 2373 } 2374 2375 net->ipv4.sysctl_tcp_ecn = 2; 2376 net->ipv4.sysctl_tcp_ecn_fallback = 1; 2377 2378 net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS; 2379 net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD; 2380 net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL; 2381 2382 return 0; 2383 fail: 2384 tcp_sk_exit(net); 2385 2386 return res; 2387 } 2388 2389 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) 2390 { 2391 inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET); 2392 } 2393 2394 static struct pernet_operations __net_initdata tcp_sk_ops = { 2395 .init = tcp_sk_init, 2396 .exit = tcp_sk_exit, 2397 .exit_batch = tcp_sk_exit_batch, 2398 }; 2399 2400 void __init tcp_v4_init(void) 2401 { 2402 inet_hashinfo_init(&tcp_hashinfo); 2403 if (register_pernet_subsys(&tcp_sk_ops)) 2404 panic("Failed to create the TCP control socket.\n"); 2405 } 2406