tcp_ipv4.c revision fb286bb2990a107009dbf25f6ffebeb7df77f9be
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 * Version: $Id: tcp_ipv4.c,v 1.240 2002/02/01 22:01:04 davem Exp $ 9 * 10 * IPv4 specific functions 11 * 12 * 13 * code split from: 14 * linux/ipv4/tcp.c 15 * linux/ipv4/tcp_input.c 16 * linux/ipv4/tcp_output.c 17 * 18 * See tcp.c for author information 19 * 20 * This program is free software; you can redistribute it and/or 21 * modify it under the terms of the GNU General Public License 22 * as published by the Free Software Foundation; either version 23 * 2 of the License, or (at your option) any later version. 24 */ 25 26/* 27 * Changes: 28 * David S. Miller : New socket lookup architecture. 29 * This code is dedicated to John Dyson. 30 * David S. Miller : Change semantics of established hash, 31 * half is devoted to TIME_WAIT sockets 32 * and the rest go in the other half. 33 * Andi Kleen : Add support for syncookies and fixed 34 * some bugs: ip options weren't passed to 35 * the TCP layer, missed a check for an 36 * ACK bit. 37 * Andi Kleen : Implemented fast path mtu discovery. 38 * Fixed many serious bugs in the 39 * request_sock handling and moved 40 * most of it into the af independent code. 41 * Added tail drop and some other bugfixes. 42 * Added new listen sematics. 43 * Mike McLagan : Routing by source 44 * Juan Jose Ciarlante: ip_dynaddr bits 45 * Andi Kleen: various fixes. 46 * Vitaly E. Lavrov : Transparent proxy revived after year 47 * coma. 48 * Andi Kleen : Fix new listen. 49 * Andi Kleen : Fix accept error reporting. 50 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which 51 * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind 52 * a single port at the same time. 53 */ 54 55#include <linux/config.h> 56 57#include <linux/types.h> 58#include <linux/fcntl.h> 59#include <linux/module.h> 60#include <linux/random.h> 61#include <linux/cache.h> 62#include <linux/jhash.h> 63#include <linux/init.h> 64#include <linux/times.h> 65 66#include <net/icmp.h> 67#include <net/inet_hashtables.h> 68#include <net/tcp.h> 69#include <net/transp_v6.h> 70#include <net/ipv6.h> 71#include <net/inet_common.h> 72#include <net/xfrm.h> 73 74#include <linux/inet.h> 75#include <linux/ipv6.h> 76#include <linux/stddef.h> 77#include <linux/proc_fs.h> 78#include <linux/seq_file.h> 79 80int sysctl_tcp_tw_reuse; 81int sysctl_tcp_low_latency; 82 83/* Check TCP sequence numbers in ICMP packets. */ 84#define ICMP_MIN_LENGTH 8 85 86/* Socket used for sending RSTs */ 87static struct socket *tcp_socket; 88 89void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len, 90 struct sk_buff *skb); 91 92struct inet_hashinfo __cacheline_aligned tcp_hashinfo = { 93 .lhash_lock = RW_LOCK_UNLOCKED, 94 .lhash_users = ATOMIC_INIT(0), 95 .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait), 96}; 97 98static int tcp_v4_get_port(struct sock *sk, unsigned short snum) 99{ 100 return inet_csk_get_port(&tcp_hashinfo, sk, snum); 101} 102 103static void tcp_v4_hash(struct sock *sk) 104{ 105 inet_hash(&tcp_hashinfo, sk); 106} 107 108void tcp_unhash(struct sock *sk) 109{ 110 inet_unhash(&tcp_hashinfo, sk); 111} 112 113static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb) 114{ 115 return secure_tcp_sequence_number(skb->nh.iph->daddr, 116 skb->nh.iph->saddr, 117 skb->h.th->dest, 118 skb->h.th->source); 119} 120 121/* called with local bh disabled */ 122static int __tcp_v4_check_established(struct sock *sk, __u16 lport, 123 struct inet_timewait_sock **twp) 124{ 125 struct inet_sock *inet = inet_sk(sk); 126 u32 daddr = inet->rcv_saddr; 127 u32 saddr = inet->daddr; 128 int dif = sk->sk_bound_dev_if; 129 INET_ADDR_COOKIE(acookie, saddr, daddr) 130 const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport); 131 unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport); 132 struct inet_ehash_bucket *head = inet_ehash_bucket(&tcp_hashinfo, hash); 133 struct sock *sk2; 134 const struct hlist_node *node; 135 struct inet_timewait_sock *tw; 136 137 prefetch(head->chain.first); 138 write_lock(&head->lock); 139 140 /* Check TIME-WAIT sockets first. */ 141 sk_for_each(sk2, node, &(head + tcp_hashinfo.ehash_size)->chain) { 142 tw = inet_twsk(sk2); 143 144 if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) { 145 const struct tcp_timewait_sock *tcptw = tcp_twsk(sk2); 146 struct tcp_sock *tp = tcp_sk(sk); 147 148 /* With PAWS, it is safe from the viewpoint 149 of data integrity. Even without PAWS it 150 is safe provided sequence spaces do not 151 overlap i.e. at data rates <= 80Mbit/sec. 152 153 Actually, the idea is close to VJ's one, 154 only timestamp cache is held not per host, 155 but per port pair and TW bucket is used 156 as state holder. 157 158 If TW bucket has been already destroyed we 159 fall back to VJ's scheme and use initial 160 timestamp retrieved from peer table. 161 */ 162 if (tcptw->tw_ts_recent_stamp && 163 (!twp || (sysctl_tcp_tw_reuse && 164 xtime.tv_sec - 165 tcptw->tw_ts_recent_stamp > 1))) { 166 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; 167 if (tp->write_seq == 0) 168 tp->write_seq = 1; 169 tp->rx_opt.ts_recent = tcptw->tw_ts_recent; 170 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; 171 sock_hold(sk2); 172 goto unique; 173 } else 174 goto not_unique; 175 } 176 } 177 tw = NULL; 178 179 /* And established part... */ 180 sk_for_each(sk2, node, &head->chain) { 181 if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) 182 goto not_unique; 183 } 184 185unique: 186 /* Must record num and sport now. Otherwise we will see 187 * in hash table socket with a funny identity. */ 188 inet->num = lport; 189 inet->sport = htons(lport); 190 sk->sk_hash = hash; 191 BUG_TRAP(sk_unhashed(sk)); 192 __sk_add_node(sk, &head->chain); 193 sock_prot_inc_use(sk->sk_prot); 194 write_unlock(&head->lock); 195 196 if (twp) { 197 *twp = tw; 198 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 199 } else if (tw) { 200 /* Silly. Should hash-dance instead... */ 201 inet_twsk_deschedule(tw, &tcp_death_row); 202 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 203 204 inet_twsk_put(tw); 205 } 206 207 return 0; 208 209not_unique: 210 write_unlock(&head->lock); 211 return -EADDRNOTAVAIL; 212} 213 214static inline u32 connect_port_offset(const struct sock *sk) 215{ 216 const struct inet_sock *inet = inet_sk(sk); 217 218 return secure_tcp_port_ephemeral(inet->rcv_saddr, inet->daddr, 219 inet->dport); 220} 221 222/* 223 * Bind a port for a connect operation and hash it. 224 */ 225static inline int tcp_v4_hash_connect(struct sock *sk) 226{ 227 const unsigned short snum = inet_sk(sk)->num; 228 struct inet_bind_hashbucket *head; 229 struct inet_bind_bucket *tb; 230 int ret; 231 232 if (!snum) { 233 int low = sysctl_local_port_range[0]; 234 int high = sysctl_local_port_range[1]; 235 int range = high - low; 236 int i; 237 int port; 238 static u32 hint; 239 u32 offset = hint + connect_port_offset(sk); 240 struct hlist_node *node; 241 struct inet_timewait_sock *tw = NULL; 242 243 local_bh_disable(); 244 for (i = 1; i <= range; i++) { 245 port = low + (i + offset) % range; 246 head = &tcp_hashinfo.bhash[inet_bhashfn(port, tcp_hashinfo.bhash_size)]; 247 spin_lock(&head->lock); 248 249 /* Does not bother with rcv_saddr checks, 250 * because the established check is already 251 * unique enough. 252 */ 253 inet_bind_bucket_for_each(tb, node, &head->chain) { 254 if (tb->port == port) { 255 BUG_TRAP(!hlist_empty(&tb->owners)); 256 if (tb->fastreuse >= 0) 257 goto next_port; 258 if (!__tcp_v4_check_established(sk, 259 port, 260 &tw)) 261 goto ok; 262 goto next_port; 263 } 264 } 265 266 tb = inet_bind_bucket_create(tcp_hashinfo.bind_bucket_cachep, head, port); 267 if (!tb) { 268 spin_unlock(&head->lock); 269 break; 270 } 271 tb->fastreuse = -1; 272 goto ok; 273 274 next_port: 275 spin_unlock(&head->lock); 276 } 277 local_bh_enable(); 278 279 return -EADDRNOTAVAIL; 280 281ok: 282 hint += i; 283 284 /* Head lock still held and bh's disabled */ 285 inet_bind_hash(sk, tb, port); 286 if (sk_unhashed(sk)) { 287 inet_sk(sk)->sport = htons(port); 288 __inet_hash(&tcp_hashinfo, sk, 0); 289 } 290 spin_unlock(&head->lock); 291 292 if (tw) { 293 inet_twsk_deschedule(tw, &tcp_death_row);; 294 inet_twsk_put(tw); 295 } 296 297 ret = 0; 298 goto out; 299 } 300 301 head = &tcp_hashinfo.bhash[inet_bhashfn(snum, tcp_hashinfo.bhash_size)]; 302 tb = inet_csk(sk)->icsk_bind_hash; 303 spin_lock_bh(&head->lock); 304 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { 305 __inet_hash(&tcp_hashinfo, sk, 0); 306 spin_unlock_bh(&head->lock); 307 return 0; 308 } else { 309 spin_unlock(&head->lock); 310 /* No definite answer... Walk to established hash table */ 311 ret = __tcp_v4_check_established(sk, snum, NULL); 312out: 313 local_bh_enable(); 314 return ret; 315 } 316} 317 318/* This will initiate an outgoing connection. */ 319int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 320{ 321 struct inet_sock *inet = inet_sk(sk); 322 struct tcp_sock *tp = tcp_sk(sk); 323 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; 324 struct rtable *rt; 325 u32 daddr, nexthop; 326 int tmp; 327 int err; 328 329 if (addr_len < sizeof(struct sockaddr_in)) 330 return -EINVAL; 331 332 if (usin->sin_family != AF_INET) 333 return -EAFNOSUPPORT; 334 335 nexthop = daddr = usin->sin_addr.s_addr; 336 if (inet->opt && inet->opt->srr) { 337 if (!daddr) 338 return -EINVAL; 339 nexthop = inet->opt->faddr; 340 } 341 342 tmp = ip_route_connect(&rt, nexthop, inet->saddr, 343 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, 344 IPPROTO_TCP, 345 inet->sport, usin->sin_port, sk); 346 if (tmp < 0) 347 return tmp; 348 349 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 350 ip_rt_put(rt); 351 return -ENETUNREACH; 352 } 353 354 if (!inet->opt || !inet->opt->srr) 355 daddr = rt->rt_dst; 356 357 if (!inet->saddr) 358 inet->saddr = rt->rt_src; 359 inet->rcv_saddr = inet->saddr; 360 361 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) { 362 /* Reset inherited state */ 363 tp->rx_opt.ts_recent = 0; 364 tp->rx_opt.ts_recent_stamp = 0; 365 tp->write_seq = 0; 366 } 367 368 if (tcp_death_row.sysctl_tw_recycle && 369 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) { 370 struct inet_peer *peer = rt_get_peer(rt); 371 372 /* VJ's idea. We save last timestamp seen from 373 * the destination in peer table, when entering state TIME-WAIT 374 * and initialize rx_opt.ts_recent from it, when trying new connection. 375 */ 376 377 if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) { 378 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp; 379 tp->rx_opt.ts_recent = peer->tcp_ts; 380 } 381 } 382 383 inet->dport = usin->sin_port; 384 inet->daddr = daddr; 385 386 tp->ext_header_len = 0; 387 if (inet->opt) 388 tp->ext_header_len = inet->opt->optlen; 389 390 tp->rx_opt.mss_clamp = 536; 391 392 /* Socket identity is still unknown (sport may be zero). 393 * However we set state to SYN-SENT and not releasing socket 394 * lock select source port, enter ourselves into the hash tables and 395 * complete initialization after this. 396 */ 397 tcp_set_state(sk, TCP_SYN_SENT); 398 err = tcp_v4_hash_connect(sk); 399 if (err) 400 goto failure; 401 402 err = ip_route_newports(&rt, inet->sport, inet->dport, sk); 403 if (err) 404 goto failure; 405 406 /* OK, now commit destination to socket. */ 407 sk_setup_caps(sk, &rt->u.dst); 408 409 if (!tp->write_seq) 410 tp->write_seq = secure_tcp_sequence_number(inet->saddr, 411 inet->daddr, 412 inet->sport, 413 usin->sin_port); 414 415 inet->id = tp->write_seq ^ jiffies; 416 417 err = tcp_connect(sk); 418 rt = NULL; 419 if (err) 420 goto failure; 421 422 return 0; 423 424failure: 425 /* This unhashes the socket and releases the local port, if necessary. */ 426 tcp_set_state(sk, TCP_CLOSE); 427 ip_rt_put(rt); 428 sk->sk_route_caps = 0; 429 inet->dport = 0; 430 return err; 431} 432 433/* 434 * This routine does path mtu discovery as defined in RFC1191. 435 */ 436static inline void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, 437 u32 mtu) 438{ 439 struct dst_entry *dst; 440 struct inet_sock *inet = inet_sk(sk); 441 struct tcp_sock *tp = tcp_sk(sk); 442 443 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs 444 * send out by Linux are always <576bytes so they should go through 445 * unfragmented). 446 */ 447 if (sk->sk_state == TCP_LISTEN) 448 return; 449 450 /* We don't check in the destentry if pmtu discovery is forbidden 451 * on this route. We just assume that no packet_to_big packets 452 * are send back when pmtu discovery is not active. 453 * There is a small race when the user changes this flag in the 454 * route, but I think that's acceptable. 455 */ 456 if ((dst = __sk_dst_check(sk, 0)) == NULL) 457 return; 458 459 dst->ops->update_pmtu(dst, mtu); 460 461 /* Something is about to be wrong... Remember soft error 462 * for the case, if this connection will not able to recover. 463 */ 464 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) 465 sk->sk_err_soft = EMSGSIZE; 466 467 mtu = dst_mtu(dst); 468 469 if (inet->pmtudisc != IP_PMTUDISC_DONT && 470 tp->pmtu_cookie > mtu) { 471 tcp_sync_mss(sk, mtu); 472 473 /* Resend the TCP packet because it's 474 * clear that the old packet has been 475 * dropped. This is the new "fast" path mtu 476 * discovery. 477 */ 478 tcp_simple_retransmit(sk); 479 } /* else let the usual retransmit timer handle it */ 480} 481 482/* 483 * This routine is called by the ICMP module when it gets some 484 * sort of error condition. If err < 0 then the socket should 485 * be closed and the error returned to the user. If err > 0 486 * it's just the icmp type << 8 | icmp code. After adjustment 487 * header points to the first 8 bytes of the tcp header. We need 488 * to find the appropriate port. 489 * 490 * The locking strategy used here is very "optimistic". When 491 * someone else accesses the socket the ICMP is just dropped 492 * and for some paths there is no check at all. 493 * A more general error queue to queue errors for later handling 494 * is probably better. 495 * 496 */ 497 498void tcp_v4_err(struct sk_buff *skb, u32 info) 499{ 500 struct iphdr *iph = (struct iphdr *)skb->data; 501 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2)); 502 struct tcp_sock *tp; 503 struct inet_sock *inet; 504 int type = skb->h.icmph->type; 505 int code = skb->h.icmph->code; 506 struct sock *sk; 507 __u32 seq; 508 int err; 509 510 if (skb->len < (iph->ihl << 2) + 8) { 511 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 512 return; 513 } 514 515 sk = inet_lookup(&tcp_hashinfo, iph->daddr, th->dest, iph->saddr, 516 th->source, inet_iif(skb)); 517 if (!sk) { 518 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 519 return; 520 } 521 if (sk->sk_state == TCP_TIME_WAIT) { 522 inet_twsk_put((struct inet_timewait_sock *)sk); 523 return; 524 } 525 526 bh_lock_sock(sk); 527 /* If too many ICMPs get dropped on busy 528 * servers this needs to be solved differently. 529 */ 530 if (sock_owned_by_user(sk)) 531 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); 532 533 if (sk->sk_state == TCP_CLOSE) 534 goto out; 535 536 tp = tcp_sk(sk); 537 seq = ntohl(th->seq); 538 if (sk->sk_state != TCP_LISTEN && 539 !between(seq, tp->snd_una, tp->snd_nxt)) { 540 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS); 541 goto out; 542 } 543 544 switch (type) { 545 case ICMP_SOURCE_QUENCH: 546 /* Just silently ignore these. */ 547 goto out; 548 case ICMP_PARAMETERPROB: 549 err = EPROTO; 550 break; 551 case ICMP_DEST_UNREACH: 552 if (code > NR_ICMP_UNREACH) 553 goto out; 554 555 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ 556 if (!sock_owned_by_user(sk)) 557 do_pmtu_discovery(sk, iph, info); 558 goto out; 559 } 560 561 err = icmp_err_convert[code].errno; 562 break; 563 case ICMP_TIME_EXCEEDED: 564 err = EHOSTUNREACH; 565 break; 566 default: 567 goto out; 568 } 569 570 switch (sk->sk_state) { 571 struct request_sock *req, **prev; 572 case TCP_LISTEN: 573 if (sock_owned_by_user(sk)) 574 goto out; 575 576 req = inet_csk_search_req(sk, &prev, th->dest, 577 iph->daddr, iph->saddr); 578 if (!req) 579 goto out; 580 581 /* ICMPs are not backlogged, hence we cannot get 582 an established socket here. 583 */ 584 BUG_TRAP(!req->sk); 585 586 if (seq != tcp_rsk(req)->snt_isn) { 587 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS); 588 goto out; 589 } 590 591 /* 592 * Still in SYN_RECV, just remove it silently. 593 * There is no good way to pass the error to the newly 594 * created socket, and POSIX does not want network 595 * errors returned from accept(). 596 */ 597 inet_csk_reqsk_queue_drop(sk, req, prev); 598 goto out; 599 600 case TCP_SYN_SENT: 601 case TCP_SYN_RECV: /* Cannot happen. 602 It can f.e. if SYNs crossed. 603 */ 604 if (!sock_owned_by_user(sk)) { 605 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); 606 sk->sk_err = err; 607 608 sk->sk_error_report(sk); 609 610 tcp_done(sk); 611 } else { 612 sk->sk_err_soft = err; 613 } 614 goto out; 615 } 616 617 /* If we've already connected we will keep trying 618 * until we time out, or the user gives up. 619 * 620 * rfc1122 4.2.3.9 allows to consider as hard errors 621 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, 622 * but it is obsoleted by pmtu discovery). 623 * 624 * Note, that in modern internet, where routing is unreliable 625 * and in each dark corner broken firewalls sit, sending random 626 * errors ordered by their masters even this two messages finally lose 627 * their original sense (even Linux sends invalid PORT_UNREACHs) 628 * 629 * Now we are in compliance with RFCs. 630 * --ANK (980905) 631 */ 632 633 inet = inet_sk(sk); 634 if (!sock_owned_by_user(sk) && inet->recverr) { 635 sk->sk_err = err; 636 sk->sk_error_report(sk); 637 } else { /* Only an error on timeout */ 638 sk->sk_err_soft = err; 639 } 640 641out: 642 bh_unlock_sock(sk); 643 sock_put(sk); 644} 645 646/* This routine computes an IPv4 TCP checksum. */ 647void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len, 648 struct sk_buff *skb) 649{ 650 struct inet_sock *inet = inet_sk(sk); 651 652 if (skb->ip_summed == CHECKSUM_HW) { 653 th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0); 654 skb->csum = offsetof(struct tcphdr, check); 655 } else { 656 th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr, 657 csum_partial((char *)th, 658 th->doff << 2, 659 skb->csum)); 660 } 661} 662 663/* 664 * This routine will send an RST to the other tcp. 665 * 666 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) 667 * for reset. 668 * Answer: if a packet caused RST, it is not for a socket 669 * existing in our system, if it is matched to a socket, 670 * it is just duplicate segment or bug in other side's TCP. 671 * So that we build reply only basing on parameters 672 * arrived with segment. 673 * Exception: precedence violation. We do not implement it in any case. 674 */ 675 676static void tcp_v4_send_reset(struct sk_buff *skb) 677{ 678 struct tcphdr *th = skb->h.th; 679 struct tcphdr rth; 680 struct ip_reply_arg arg; 681 682 /* Never send a reset in response to a reset. */ 683 if (th->rst) 684 return; 685 686 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL) 687 return; 688 689 /* Swap the send and the receive. */ 690 memset(&rth, 0, sizeof(struct tcphdr)); 691 rth.dest = th->source; 692 rth.source = th->dest; 693 rth.doff = sizeof(struct tcphdr) / 4; 694 rth.rst = 1; 695 696 if (th->ack) { 697 rth.seq = th->ack_seq; 698 } else { 699 rth.ack = 1; 700 rth.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + 701 skb->len - (th->doff << 2)); 702 } 703 704 memset(&arg, 0, sizeof arg); 705 arg.iov[0].iov_base = (unsigned char *)&rth; 706 arg.iov[0].iov_len = sizeof rth; 707 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr, 708 skb->nh.iph->saddr, /*XXX*/ 709 sizeof(struct tcphdr), IPPROTO_TCP, 0); 710 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 711 712 ip_send_reply(tcp_socket->sk, skb, &arg, sizeof rth); 713 714 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS); 715 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS); 716} 717 718/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 719 outside socket context is ugly, certainly. What can I do? 720 */ 721 722static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, 723 u32 win, u32 ts) 724{ 725 struct tcphdr *th = skb->h.th; 726 struct { 727 struct tcphdr th; 728 u32 tsopt[3]; 729 } rep; 730 struct ip_reply_arg arg; 731 732 memset(&rep.th, 0, sizeof(struct tcphdr)); 733 memset(&arg, 0, sizeof arg); 734 735 arg.iov[0].iov_base = (unsigned char *)&rep; 736 arg.iov[0].iov_len = sizeof(rep.th); 737 if (ts) { 738 rep.tsopt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 739 (TCPOPT_TIMESTAMP << 8) | 740 TCPOLEN_TIMESTAMP); 741 rep.tsopt[1] = htonl(tcp_time_stamp); 742 rep.tsopt[2] = htonl(ts); 743 arg.iov[0].iov_len = sizeof(rep); 744 } 745 746 /* Swap the send and the receive. */ 747 rep.th.dest = th->source; 748 rep.th.source = th->dest; 749 rep.th.doff = arg.iov[0].iov_len / 4; 750 rep.th.seq = htonl(seq); 751 rep.th.ack_seq = htonl(ack); 752 rep.th.ack = 1; 753 rep.th.window = htons(win); 754 755 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr, 756 skb->nh.iph->saddr, /*XXX*/ 757 arg.iov[0].iov_len, IPPROTO_TCP, 0); 758 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 759 760 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len); 761 762 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS); 763} 764 765static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 766{ 767 struct inet_timewait_sock *tw = inet_twsk(sk); 768 const struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 769 770 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 771 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcptw->tw_ts_recent); 772 773 inet_twsk_put(tw); 774} 775 776static void tcp_v4_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req) 777{ 778 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, 779 req->ts_recent); 780} 781 782/* 783 * Send a SYN-ACK after having received an ACK. 784 * This still operates on a request_sock only, not on a big 785 * socket. 786 */ 787static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req, 788 struct dst_entry *dst) 789{ 790 const struct inet_request_sock *ireq = inet_rsk(req); 791 int err = -1; 792 struct sk_buff * skb; 793 794 /* First, grab a route. */ 795 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL) 796 goto out; 797 798 skb = tcp_make_synack(sk, dst, req); 799 800 if (skb) { 801 struct tcphdr *th = skb->h.th; 802 803 th->check = tcp_v4_check(th, skb->len, 804 ireq->loc_addr, 805 ireq->rmt_addr, 806 csum_partial((char *)th, skb->len, 807 skb->csum)); 808 809 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, 810 ireq->rmt_addr, 811 ireq->opt); 812 if (err == NET_XMIT_CN) 813 err = 0; 814 } 815 816out: 817 dst_release(dst); 818 return err; 819} 820 821/* 822 * IPv4 request_sock destructor. 823 */ 824static void tcp_v4_reqsk_destructor(struct request_sock *req) 825{ 826 kfree(inet_rsk(req)->opt); 827} 828 829static inline void syn_flood_warning(struct sk_buff *skb) 830{ 831 static unsigned long warntime; 832 833 if (time_after(jiffies, (warntime + HZ * 60))) { 834 warntime = jiffies; 835 printk(KERN_INFO 836 "possible SYN flooding on port %d. Sending cookies.\n", 837 ntohs(skb->h.th->dest)); 838 } 839} 840 841/* 842 * Save and compile IPv4 options into the request_sock if needed. 843 */ 844static inline struct ip_options *tcp_v4_save_options(struct sock *sk, 845 struct sk_buff *skb) 846{ 847 struct ip_options *opt = &(IPCB(skb)->opt); 848 struct ip_options *dopt = NULL; 849 850 if (opt && opt->optlen) { 851 int opt_size = optlength(opt); 852 dopt = kmalloc(opt_size, GFP_ATOMIC); 853 if (dopt) { 854 if (ip_options_echo(dopt, skb)) { 855 kfree(dopt); 856 dopt = NULL; 857 } 858 } 859 } 860 return dopt; 861} 862 863struct request_sock_ops tcp_request_sock_ops = { 864 .family = PF_INET, 865 .obj_size = sizeof(struct tcp_request_sock), 866 .rtx_syn_ack = tcp_v4_send_synack, 867 .send_ack = tcp_v4_reqsk_send_ack, 868 .destructor = tcp_v4_reqsk_destructor, 869 .send_reset = tcp_v4_send_reset, 870}; 871 872int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 873{ 874 struct inet_request_sock *ireq; 875 struct tcp_options_received tmp_opt; 876 struct request_sock *req; 877 __u32 saddr = skb->nh.iph->saddr; 878 __u32 daddr = skb->nh.iph->daddr; 879 __u32 isn = TCP_SKB_CB(skb)->when; 880 struct dst_entry *dst = NULL; 881#ifdef CONFIG_SYN_COOKIES 882 int want_cookie = 0; 883#else 884#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */ 885#endif 886 887 /* Never answer to SYNs send to broadcast or multicast */ 888 if (((struct rtable *)skb->dst)->rt_flags & 889 (RTCF_BROADCAST | RTCF_MULTICAST)) 890 goto drop; 891 892 /* TW buckets are converted to open requests without 893 * limitations, they conserve resources and peer is 894 * evidently real one. 895 */ 896 if (inet_csk_reqsk_queue_is_full(sk) && !isn) { 897#ifdef CONFIG_SYN_COOKIES 898 if (sysctl_tcp_syncookies) { 899 want_cookie = 1; 900 } else 901#endif 902 goto drop; 903 } 904 905 /* Accept backlog is full. If we have already queued enough 906 * of warm entries in syn queue, drop request. It is better than 907 * clogging syn queue with openreqs with exponentially increasing 908 * timeout. 909 */ 910 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) 911 goto drop; 912 913 req = reqsk_alloc(&tcp_request_sock_ops); 914 if (!req) 915 goto drop; 916 917 tcp_clear_options(&tmp_opt); 918 tmp_opt.mss_clamp = 536; 919 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss; 920 921 tcp_parse_options(skb, &tmp_opt, 0); 922 923 if (want_cookie) { 924 tcp_clear_options(&tmp_opt); 925 tmp_opt.saw_tstamp = 0; 926 } 927 928 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) { 929 /* Some OSes (unknown ones, but I see them on web server, which 930 * contains information interesting only for windows' 931 * users) do not send their stamp in SYN. It is easy case. 932 * We simply do not advertise TS support. 933 */ 934 tmp_opt.saw_tstamp = 0; 935 tmp_opt.tstamp_ok = 0; 936 } 937 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp; 938 939 tcp_openreq_init(req, &tmp_opt, skb); 940 941 ireq = inet_rsk(req); 942 ireq->loc_addr = daddr; 943 ireq->rmt_addr = saddr; 944 ireq->opt = tcp_v4_save_options(sk, skb); 945 if (!want_cookie) 946 TCP_ECN_create_request(req, skb->h.th); 947 948 if (want_cookie) { 949#ifdef CONFIG_SYN_COOKIES 950 syn_flood_warning(skb); 951#endif 952 isn = cookie_v4_init_sequence(sk, skb, &req->mss); 953 } else if (!isn) { 954 struct inet_peer *peer = NULL; 955 956 /* VJ's idea. We save last timestamp seen 957 * from the destination in peer table, when entering 958 * state TIME-WAIT, and check against it before 959 * accepting new connection request. 960 * 961 * If "isn" is not zero, this request hit alive 962 * timewait bucket, so that all the necessary checks 963 * are made in the function processing timewait state. 964 */ 965 if (tmp_opt.saw_tstamp && 966 tcp_death_row.sysctl_tw_recycle && 967 (dst = inet_csk_route_req(sk, req)) != NULL && 968 (peer = rt_get_peer((struct rtable *)dst)) != NULL && 969 peer->v4daddr == saddr) { 970 if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL && 971 (s32)(peer->tcp_ts - req->ts_recent) > 972 TCP_PAWS_WINDOW) { 973 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED); 974 dst_release(dst); 975 goto drop_and_free; 976 } 977 } 978 /* Kill the following clause, if you dislike this way. */ 979 else if (!sysctl_tcp_syncookies && 980 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) < 981 (sysctl_max_syn_backlog >> 2)) && 982 (!peer || !peer->tcp_ts_stamp) && 983 (!dst || !dst_metric(dst, RTAX_RTT))) { 984 /* Without syncookies last quarter of 985 * backlog is filled with destinations, 986 * proven to be alive. 987 * It means that we continue to communicate 988 * to destinations, already remembered 989 * to the moment of synflood. 990 */ 991 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open " 992 "request from %u.%u.%u.%u/%u\n", 993 NIPQUAD(saddr), 994 ntohs(skb->h.th->source)); 995 dst_release(dst); 996 goto drop_and_free; 997 } 998 999 isn = tcp_v4_init_sequence(sk, skb); 1000 } 1001 tcp_rsk(req)->snt_isn = isn; 1002 1003 if (tcp_v4_send_synack(sk, req, dst)) 1004 goto drop_and_free; 1005 1006 if (want_cookie) { 1007 reqsk_free(req); 1008 } else { 1009 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT); 1010 } 1011 return 0; 1012 1013drop_and_free: 1014 reqsk_free(req); 1015drop: 1016 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); 1017 return 0; 1018} 1019 1020 1021/* 1022 * The three way handshake has completed - we got a valid synack - 1023 * now create the new socket. 1024 */ 1025struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, 1026 struct request_sock *req, 1027 struct dst_entry *dst) 1028{ 1029 struct inet_request_sock *ireq; 1030 struct inet_sock *newinet; 1031 struct tcp_sock *newtp; 1032 struct sock *newsk; 1033 1034 if (sk_acceptq_is_full(sk)) 1035 goto exit_overflow; 1036 1037 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL) 1038 goto exit; 1039 1040 newsk = tcp_create_openreq_child(sk, req, skb); 1041 if (!newsk) 1042 goto exit; 1043 1044 sk_setup_caps(newsk, dst); 1045 1046 newtp = tcp_sk(newsk); 1047 newinet = inet_sk(newsk); 1048 ireq = inet_rsk(req); 1049 newinet->daddr = ireq->rmt_addr; 1050 newinet->rcv_saddr = ireq->loc_addr; 1051 newinet->saddr = ireq->loc_addr; 1052 newinet->opt = ireq->opt; 1053 ireq->opt = NULL; 1054 newinet->mc_index = inet_iif(skb); 1055 newinet->mc_ttl = skb->nh.iph->ttl; 1056 newtp->ext_header_len = 0; 1057 if (newinet->opt) 1058 newtp->ext_header_len = newinet->opt->optlen; 1059 newinet->id = newtp->write_seq ^ jiffies; 1060 1061 tcp_sync_mss(newsk, dst_mtu(dst)); 1062 newtp->advmss = dst_metric(dst, RTAX_ADVMSS); 1063 tcp_initialize_rcv_mss(newsk); 1064 1065 __inet_hash(&tcp_hashinfo, newsk, 0); 1066 __inet_inherit_port(&tcp_hashinfo, sk, newsk); 1067 1068 return newsk; 1069 1070exit_overflow: 1071 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS); 1072exit: 1073 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS); 1074 dst_release(dst); 1075 return NULL; 1076} 1077 1078static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) 1079{ 1080 struct tcphdr *th = skb->h.th; 1081 struct iphdr *iph = skb->nh.iph; 1082 struct sock *nsk; 1083 struct request_sock **prev; 1084 /* Find possible connection requests. */ 1085 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source, 1086 iph->saddr, iph->daddr); 1087 if (req) 1088 return tcp_check_req(sk, skb, req, prev); 1089 1090 nsk = __inet_lookup_established(&tcp_hashinfo, skb->nh.iph->saddr, 1091 th->source, skb->nh.iph->daddr, 1092 ntohs(th->dest), inet_iif(skb)); 1093 1094 if (nsk) { 1095 if (nsk->sk_state != TCP_TIME_WAIT) { 1096 bh_lock_sock(nsk); 1097 return nsk; 1098 } 1099 inet_twsk_put((struct inet_timewait_sock *)nsk); 1100 return NULL; 1101 } 1102 1103#ifdef CONFIG_SYN_COOKIES 1104 if (!th->rst && !th->syn && th->ack) 1105 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt)); 1106#endif 1107 return sk; 1108} 1109 1110static int tcp_v4_checksum_init(struct sk_buff *skb) 1111{ 1112 if (skb->ip_summed == CHECKSUM_HW) { 1113 if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr, 1114 skb->nh.iph->daddr, skb->csum)) { 1115 skb->ip_summed = CHECKSUM_UNNECESSARY; 1116 return 0; 1117 } 1118 } 1119 1120 skb->csum = csum_tcpudp_nofold(skb->nh.iph->saddr, skb->nh.iph->daddr, 1121 skb->len, IPPROTO_TCP, 0); 1122 1123 if (skb->len <= 76) { 1124 return __skb_checksum_complete(skb); 1125 } 1126 return 0; 1127} 1128 1129 1130/* The socket must have it's spinlock held when we get 1131 * here. 1132 * 1133 * We have a potential double-lock case here, so even when 1134 * doing backlog processing we use the BH locking scheme. 1135 * This is because we cannot sleep with the original spinlock 1136 * held. 1137 */ 1138int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1139{ 1140 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1141 TCP_CHECK_TIMER(sk); 1142 if (tcp_rcv_established(sk, skb, skb->h.th, skb->len)) 1143 goto reset; 1144 TCP_CHECK_TIMER(sk); 1145 return 0; 1146 } 1147 1148 if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb)) 1149 goto csum_err; 1150 1151 if (sk->sk_state == TCP_LISTEN) { 1152 struct sock *nsk = tcp_v4_hnd_req(sk, skb); 1153 if (!nsk) 1154 goto discard; 1155 1156 if (nsk != sk) { 1157 if (tcp_child_process(sk, nsk, skb)) 1158 goto reset; 1159 return 0; 1160 } 1161 } 1162 1163 TCP_CHECK_TIMER(sk); 1164 if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len)) 1165 goto reset; 1166 TCP_CHECK_TIMER(sk); 1167 return 0; 1168 1169reset: 1170 tcp_v4_send_reset(skb); 1171discard: 1172 kfree_skb(skb); 1173 /* Be careful here. If this function gets more complicated and 1174 * gcc suffers from register pressure on the x86, sk (in %ebx) 1175 * might be destroyed here. This current version compiles correctly, 1176 * but you have been warned. 1177 */ 1178 return 0; 1179 1180csum_err: 1181 TCP_INC_STATS_BH(TCP_MIB_INERRS); 1182 goto discard; 1183} 1184 1185/* 1186 * From tcp_input.c 1187 */ 1188 1189int tcp_v4_rcv(struct sk_buff *skb) 1190{ 1191 struct tcphdr *th; 1192 struct sock *sk; 1193 int ret; 1194 1195 if (skb->pkt_type != PACKET_HOST) 1196 goto discard_it; 1197 1198 /* Count it even if it's bad */ 1199 TCP_INC_STATS_BH(TCP_MIB_INSEGS); 1200 1201 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 1202 goto discard_it; 1203 1204 th = skb->h.th; 1205 1206 if (th->doff < sizeof(struct tcphdr) / 4) 1207 goto bad_packet; 1208 if (!pskb_may_pull(skb, th->doff * 4)) 1209 goto discard_it; 1210 1211 /* An explanation is required here, I think. 1212 * Packet length and doff are validated by header prediction, 1213 * provided case of th->doff==0 is elimineted. 1214 * So, we defer the checks. */ 1215 if ((skb->ip_summed != CHECKSUM_UNNECESSARY && 1216 tcp_v4_checksum_init(skb))) 1217 goto bad_packet; 1218 1219 th = skb->h.th; 1220 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 1221 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 1222 skb->len - th->doff * 4); 1223 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 1224 TCP_SKB_CB(skb)->when = 0; 1225 TCP_SKB_CB(skb)->flags = skb->nh.iph->tos; 1226 TCP_SKB_CB(skb)->sacked = 0; 1227 1228 sk = __inet_lookup(&tcp_hashinfo, skb->nh.iph->saddr, th->source, 1229 skb->nh.iph->daddr, ntohs(th->dest), 1230 inet_iif(skb)); 1231 1232 if (!sk) 1233 goto no_tcp_socket; 1234 1235process: 1236 if (sk->sk_state == TCP_TIME_WAIT) 1237 goto do_time_wait; 1238 1239 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 1240 goto discard_and_relse; 1241 1242 if (sk_filter(sk, skb, 0)) 1243 goto discard_and_relse; 1244 1245 skb->dev = NULL; 1246 1247 bh_lock_sock(sk); 1248 ret = 0; 1249 if (!sock_owned_by_user(sk)) { 1250 if (!tcp_prequeue(sk, skb)) 1251 ret = tcp_v4_do_rcv(sk, skb); 1252 } else 1253 sk_add_backlog(sk, skb); 1254 bh_unlock_sock(sk); 1255 1256 sock_put(sk); 1257 1258 return ret; 1259 1260no_tcp_socket: 1261 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 1262 goto discard_it; 1263 1264 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { 1265bad_packet: 1266 TCP_INC_STATS_BH(TCP_MIB_INERRS); 1267 } else { 1268 tcp_v4_send_reset(skb); 1269 } 1270 1271discard_it: 1272 /* Discard frame. */ 1273 kfree_skb(skb); 1274 return 0; 1275 1276discard_and_relse: 1277 sock_put(sk); 1278 goto discard_it; 1279 1280do_time_wait: 1281 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 1282 inet_twsk_put((struct inet_timewait_sock *) sk); 1283 goto discard_it; 1284 } 1285 1286 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { 1287 TCP_INC_STATS_BH(TCP_MIB_INERRS); 1288 inet_twsk_put((struct inet_timewait_sock *) sk); 1289 goto discard_it; 1290 } 1291 switch (tcp_timewait_state_process((struct inet_timewait_sock *)sk, 1292 skb, th)) { 1293 case TCP_TW_SYN: { 1294 struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo, 1295 skb->nh.iph->daddr, 1296 ntohs(th->dest), 1297 inet_iif(skb)); 1298 if (sk2) { 1299 inet_twsk_deschedule((struct inet_timewait_sock *)sk, 1300 &tcp_death_row); 1301 inet_twsk_put((struct inet_timewait_sock *)sk); 1302 sk = sk2; 1303 goto process; 1304 } 1305 /* Fall through to ACK */ 1306 } 1307 case TCP_TW_ACK: 1308 tcp_v4_timewait_ack(sk, skb); 1309 break; 1310 case TCP_TW_RST: 1311 goto no_tcp_socket; 1312 case TCP_TW_SUCCESS:; 1313 } 1314 goto discard_it; 1315} 1316 1317static void v4_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr) 1318{ 1319 struct sockaddr_in *sin = (struct sockaddr_in *) uaddr; 1320 struct inet_sock *inet = inet_sk(sk); 1321 1322 sin->sin_family = AF_INET; 1323 sin->sin_addr.s_addr = inet->daddr; 1324 sin->sin_port = inet->dport; 1325} 1326 1327/* VJ's idea. Save last timestamp seen from this destination 1328 * and hold it at least for normal timewait interval to use for duplicate 1329 * segment detection in subsequent connections, before they enter synchronized 1330 * state. 1331 */ 1332 1333int tcp_v4_remember_stamp(struct sock *sk) 1334{ 1335 struct inet_sock *inet = inet_sk(sk); 1336 struct tcp_sock *tp = tcp_sk(sk); 1337 struct rtable *rt = (struct rtable *)__sk_dst_get(sk); 1338 struct inet_peer *peer = NULL; 1339 int release_it = 0; 1340 1341 if (!rt || rt->rt_dst != inet->daddr) { 1342 peer = inet_getpeer(inet->daddr, 1); 1343 release_it = 1; 1344 } else { 1345 if (!rt->peer) 1346 rt_bind_peer(rt, 1); 1347 peer = rt->peer; 1348 } 1349 1350 if (peer) { 1351 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 || 1352 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec && 1353 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) { 1354 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp; 1355 peer->tcp_ts = tp->rx_opt.ts_recent; 1356 } 1357 if (release_it) 1358 inet_putpeer(peer); 1359 return 1; 1360 } 1361 1362 return 0; 1363} 1364 1365int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw) 1366{ 1367 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1); 1368 1369 if (peer) { 1370 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw); 1371 1372 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 || 1373 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec && 1374 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) { 1375 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp; 1376 peer->tcp_ts = tcptw->tw_ts_recent; 1377 } 1378 inet_putpeer(peer); 1379 return 1; 1380 } 1381 1382 return 0; 1383} 1384 1385struct tcp_func ipv4_specific = { 1386 .queue_xmit = ip_queue_xmit, 1387 .send_check = tcp_v4_send_check, 1388 .rebuild_header = inet_sk_rebuild_header, 1389 .conn_request = tcp_v4_conn_request, 1390 .syn_recv_sock = tcp_v4_syn_recv_sock, 1391 .remember_stamp = tcp_v4_remember_stamp, 1392 .net_header_len = sizeof(struct iphdr), 1393 .setsockopt = ip_setsockopt, 1394 .getsockopt = ip_getsockopt, 1395 .addr2sockaddr = v4_addr2sockaddr, 1396 .sockaddr_len = sizeof(struct sockaddr_in), 1397}; 1398 1399/* NOTE: A lot of things set to zero explicitly by call to 1400 * sk_alloc() so need not be done here. 1401 */ 1402static int tcp_v4_init_sock(struct sock *sk) 1403{ 1404 struct inet_connection_sock *icsk = inet_csk(sk); 1405 struct tcp_sock *tp = tcp_sk(sk); 1406 1407 skb_queue_head_init(&tp->out_of_order_queue); 1408 tcp_init_xmit_timers(sk); 1409 tcp_prequeue_init(tp); 1410 1411 icsk->icsk_rto = TCP_TIMEOUT_INIT; 1412 tp->mdev = TCP_TIMEOUT_INIT; 1413 1414 /* So many TCP implementations out there (incorrectly) count the 1415 * initial SYN frame in their delayed-ACK and congestion control 1416 * algorithms that we must have the following bandaid to talk 1417 * efficiently to them. -DaveM 1418 */ 1419 tp->snd_cwnd = 2; 1420 1421 /* See draft-stevens-tcpca-spec-01 for discussion of the 1422 * initialization of these values. 1423 */ 1424 tp->snd_ssthresh = 0x7fffffff; /* Infinity */ 1425 tp->snd_cwnd_clamp = ~0; 1426 tp->mss_cache = 536; 1427 1428 tp->reordering = sysctl_tcp_reordering; 1429 icsk->icsk_ca_ops = &tcp_init_congestion_ops; 1430 1431 sk->sk_state = TCP_CLOSE; 1432 1433 sk->sk_write_space = sk_stream_write_space; 1434 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 1435 1436 tp->af_specific = &ipv4_specific; 1437 1438 sk->sk_sndbuf = sysctl_tcp_wmem[1]; 1439 sk->sk_rcvbuf = sysctl_tcp_rmem[1]; 1440 1441 atomic_inc(&tcp_sockets_allocated); 1442 1443 return 0; 1444} 1445 1446int tcp_v4_destroy_sock(struct sock *sk) 1447{ 1448 struct tcp_sock *tp = tcp_sk(sk); 1449 1450 tcp_clear_xmit_timers(sk); 1451 1452 tcp_cleanup_congestion_control(sk); 1453 1454 /* Cleanup up the write buffer. */ 1455 sk_stream_writequeue_purge(sk); 1456 1457 /* Cleans up our, hopefully empty, out_of_order_queue. */ 1458 __skb_queue_purge(&tp->out_of_order_queue); 1459 1460 /* Clean prequeue, it must be empty really */ 1461 __skb_queue_purge(&tp->ucopy.prequeue); 1462 1463 /* Clean up a referenced TCP bind bucket. */ 1464 if (inet_csk(sk)->icsk_bind_hash) 1465 inet_put_port(&tcp_hashinfo, sk); 1466 1467 /* 1468 * If sendmsg cached page exists, toss it. 1469 */ 1470 if (sk->sk_sndmsg_page) { 1471 __free_page(sk->sk_sndmsg_page); 1472 sk->sk_sndmsg_page = NULL; 1473 } 1474 1475 atomic_dec(&tcp_sockets_allocated); 1476 1477 return 0; 1478} 1479 1480EXPORT_SYMBOL(tcp_v4_destroy_sock); 1481 1482#ifdef CONFIG_PROC_FS 1483/* Proc filesystem TCP sock list dumping. */ 1484 1485static inline struct inet_timewait_sock *tw_head(struct hlist_head *head) 1486{ 1487 return hlist_empty(head) ? NULL : 1488 list_entry(head->first, struct inet_timewait_sock, tw_node); 1489} 1490 1491static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw) 1492{ 1493 return tw->tw_node.next ? 1494 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL; 1495} 1496 1497static void *listening_get_next(struct seq_file *seq, void *cur) 1498{ 1499 struct inet_connection_sock *icsk; 1500 struct hlist_node *node; 1501 struct sock *sk = cur; 1502 struct tcp_iter_state* st = seq->private; 1503 1504 if (!sk) { 1505 st->bucket = 0; 1506 sk = sk_head(&tcp_hashinfo.listening_hash[0]); 1507 goto get_sk; 1508 } 1509 1510 ++st->num; 1511 1512 if (st->state == TCP_SEQ_STATE_OPENREQ) { 1513 struct request_sock *req = cur; 1514 1515 icsk = inet_csk(st->syn_wait_sk); 1516 req = req->dl_next; 1517 while (1) { 1518 while (req) { 1519 if (req->rsk_ops->family == st->family) { 1520 cur = req; 1521 goto out; 1522 } 1523 req = req->dl_next; 1524 } 1525 if (++st->sbucket >= TCP_SYNQ_HSIZE) 1526 break; 1527get_req: 1528 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket]; 1529 } 1530 sk = sk_next(st->syn_wait_sk); 1531 st->state = TCP_SEQ_STATE_LISTENING; 1532 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1533 } else { 1534 icsk = inet_csk(sk); 1535 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1536 if (reqsk_queue_len(&icsk->icsk_accept_queue)) 1537 goto start_req; 1538 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1539 sk = sk_next(sk); 1540 } 1541get_sk: 1542 sk_for_each_from(sk, node) { 1543 if (sk->sk_family == st->family) { 1544 cur = sk; 1545 goto out; 1546 } 1547 icsk = inet_csk(sk); 1548 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1549 if (reqsk_queue_len(&icsk->icsk_accept_queue)) { 1550start_req: 1551 st->uid = sock_i_uid(sk); 1552 st->syn_wait_sk = sk; 1553 st->state = TCP_SEQ_STATE_OPENREQ; 1554 st->sbucket = 0; 1555 goto get_req; 1556 } 1557 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1558 } 1559 if (++st->bucket < INET_LHTABLE_SIZE) { 1560 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]); 1561 goto get_sk; 1562 } 1563 cur = NULL; 1564out: 1565 return cur; 1566} 1567 1568static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 1569{ 1570 void *rc = listening_get_next(seq, NULL); 1571 1572 while (rc && *pos) { 1573 rc = listening_get_next(seq, rc); 1574 --*pos; 1575 } 1576 return rc; 1577} 1578 1579static void *established_get_first(struct seq_file *seq) 1580{ 1581 struct tcp_iter_state* st = seq->private; 1582 void *rc = NULL; 1583 1584 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) { 1585 struct sock *sk; 1586 struct hlist_node *node; 1587 struct inet_timewait_sock *tw; 1588 1589 /* We can reschedule _before_ having picked the target: */ 1590 cond_resched_softirq(); 1591 1592 read_lock(&tcp_hashinfo.ehash[st->bucket].lock); 1593 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { 1594 if (sk->sk_family != st->family) { 1595 continue; 1596 } 1597 rc = sk; 1598 goto out; 1599 } 1600 st->state = TCP_SEQ_STATE_TIME_WAIT; 1601 inet_twsk_for_each(tw, node, 1602 &tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain) { 1603 if (tw->tw_family != st->family) { 1604 continue; 1605 } 1606 rc = tw; 1607 goto out; 1608 } 1609 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock); 1610 st->state = TCP_SEQ_STATE_ESTABLISHED; 1611 } 1612out: 1613 return rc; 1614} 1615 1616static void *established_get_next(struct seq_file *seq, void *cur) 1617{ 1618 struct sock *sk = cur; 1619 struct inet_timewait_sock *tw; 1620 struct hlist_node *node; 1621 struct tcp_iter_state* st = seq->private; 1622 1623 ++st->num; 1624 1625 if (st->state == TCP_SEQ_STATE_TIME_WAIT) { 1626 tw = cur; 1627 tw = tw_next(tw); 1628get_tw: 1629 while (tw && tw->tw_family != st->family) { 1630 tw = tw_next(tw); 1631 } 1632 if (tw) { 1633 cur = tw; 1634 goto out; 1635 } 1636 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock); 1637 st->state = TCP_SEQ_STATE_ESTABLISHED; 1638 1639 /* We can reschedule between buckets: */ 1640 cond_resched_softirq(); 1641 1642 if (++st->bucket < tcp_hashinfo.ehash_size) { 1643 read_lock(&tcp_hashinfo.ehash[st->bucket].lock); 1644 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain); 1645 } else { 1646 cur = NULL; 1647 goto out; 1648 } 1649 } else 1650 sk = sk_next(sk); 1651 1652 sk_for_each_from(sk, node) { 1653 if (sk->sk_family == st->family) 1654 goto found; 1655 } 1656 1657 st->state = TCP_SEQ_STATE_TIME_WAIT; 1658 tw = tw_head(&tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain); 1659 goto get_tw; 1660found: 1661 cur = sk; 1662out: 1663 return cur; 1664} 1665 1666static void *established_get_idx(struct seq_file *seq, loff_t pos) 1667{ 1668 void *rc = established_get_first(seq); 1669 1670 while (rc && pos) { 1671 rc = established_get_next(seq, rc); 1672 --pos; 1673 } 1674 return rc; 1675} 1676 1677static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 1678{ 1679 void *rc; 1680 struct tcp_iter_state* st = seq->private; 1681 1682 inet_listen_lock(&tcp_hashinfo); 1683 st->state = TCP_SEQ_STATE_LISTENING; 1684 rc = listening_get_idx(seq, &pos); 1685 1686 if (!rc) { 1687 inet_listen_unlock(&tcp_hashinfo); 1688 local_bh_disable(); 1689 st->state = TCP_SEQ_STATE_ESTABLISHED; 1690 rc = established_get_idx(seq, pos); 1691 } 1692 1693 return rc; 1694} 1695 1696static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 1697{ 1698 struct tcp_iter_state* st = seq->private; 1699 st->state = TCP_SEQ_STATE_LISTENING; 1700 st->num = 0; 1701 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 1702} 1703 1704static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1705{ 1706 void *rc = NULL; 1707 struct tcp_iter_state* st; 1708 1709 if (v == SEQ_START_TOKEN) { 1710 rc = tcp_get_idx(seq, 0); 1711 goto out; 1712 } 1713 st = seq->private; 1714 1715 switch (st->state) { 1716 case TCP_SEQ_STATE_OPENREQ: 1717 case TCP_SEQ_STATE_LISTENING: 1718 rc = listening_get_next(seq, v); 1719 if (!rc) { 1720 inet_listen_unlock(&tcp_hashinfo); 1721 local_bh_disable(); 1722 st->state = TCP_SEQ_STATE_ESTABLISHED; 1723 rc = established_get_first(seq); 1724 } 1725 break; 1726 case TCP_SEQ_STATE_ESTABLISHED: 1727 case TCP_SEQ_STATE_TIME_WAIT: 1728 rc = established_get_next(seq, v); 1729 break; 1730 } 1731out: 1732 ++*pos; 1733 return rc; 1734} 1735 1736static void tcp_seq_stop(struct seq_file *seq, void *v) 1737{ 1738 struct tcp_iter_state* st = seq->private; 1739 1740 switch (st->state) { 1741 case TCP_SEQ_STATE_OPENREQ: 1742 if (v) { 1743 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk); 1744 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1745 } 1746 case TCP_SEQ_STATE_LISTENING: 1747 if (v != SEQ_START_TOKEN) 1748 inet_listen_unlock(&tcp_hashinfo); 1749 break; 1750 case TCP_SEQ_STATE_TIME_WAIT: 1751 case TCP_SEQ_STATE_ESTABLISHED: 1752 if (v) 1753 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock); 1754 local_bh_enable(); 1755 break; 1756 } 1757} 1758 1759static int tcp_seq_open(struct inode *inode, struct file *file) 1760{ 1761 struct tcp_seq_afinfo *afinfo = PDE(inode)->data; 1762 struct seq_file *seq; 1763 struct tcp_iter_state *s; 1764 int rc; 1765 1766 if (unlikely(afinfo == NULL)) 1767 return -EINVAL; 1768 1769 s = kmalloc(sizeof(*s), GFP_KERNEL); 1770 if (!s) 1771 return -ENOMEM; 1772 memset(s, 0, sizeof(*s)); 1773 s->family = afinfo->family; 1774 s->seq_ops.start = tcp_seq_start; 1775 s->seq_ops.next = tcp_seq_next; 1776 s->seq_ops.show = afinfo->seq_show; 1777 s->seq_ops.stop = tcp_seq_stop; 1778 1779 rc = seq_open(file, &s->seq_ops); 1780 if (rc) 1781 goto out_kfree; 1782 seq = file->private_data; 1783 seq->private = s; 1784out: 1785 return rc; 1786out_kfree: 1787 kfree(s); 1788 goto out; 1789} 1790 1791int tcp_proc_register(struct tcp_seq_afinfo *afinfo) 1792{ 1793 int rc = 0; 1794 struct proc_dir_entry *p; 1795 1796 if (!afinfo) 1797 return -EINVAL; 1798 afinfo->seq_fops->owner = afinfo->owner; 1799 afinfo->seq_fops->open = tcp_seq_open; 1800 afinfo->seq_fops->read = seq_read; 1801 afinfo->seq_fops->llseek = seq_lseek; 1802 afinfo->seq_fops->release = seq_release_private; 1803 1804 p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops); 1805 if (p) 1806 p->data = afinfo; 1807 else 1808 rc = -ENOMEM; 1809 return rc; 1810} 1811 1812void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo) 1813{ 1814 if (!afinfo) 1815 return; 1816 proc_net_remove(afinfo->name); 1817 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops)); 1818} 1819 1820static void get_openreq4(struct sock *sk, struct request_sock *req, 1821 char *tmpbuf, int i, int uid) 1822{ 1823 const struct inet_request_sock *ireq = inet_rsk(req); 1824 int ttd = req->expires - jiffies; 1825 1826 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X" 1827 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p", 1828 i, 1829 ireq->loc_addr, 1830 ntohs(inet_sk(sk)->sport), 1831 ireq->rmt_addr, 1832 ntohs(ireq->rmt_port), 1833 TCP_SYN_RECV, 1834 0, 0, /* could print option size, but that is af dependent. */ 1835 1, /* timers active (only the expire timer) */ 1836 jiffies_to_clock_t(ttd), 1837 req->retrans, 1838 uid, 1839 0, /* non standard timer */ 1840 0, /* open_requests have no inode */ 1841 atomic_read(&sk->sk_refcnt), 1842 req); 1843} 1844 1845static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i) 1846{ 1847 int timer_active; 1848 unsigned long timer_expires; 1849 struct tcp_sock *tp = tcp_sk(sp); 1850 const struct inet_connection_sock *icsk = inet_csk(sp); 1851 struct inet_sock *inet = inet_sk(sp); 1852 unsigned int dest = inet->daddr; 1853 unsigned int src = inet->rcv_saddr; 1854 __u16 destp = ntohs(inet->dport); 1855 __u16 srcp = ntohs(inet->sport); 1856 1857 if (icsk->icsk_pending == ICSK_TIME_RETRANS) { 1858 timer_active = 1; 1859 timer_expires = icsk->icsk_timeout; 1860 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 1861 timer_active = 4; 1862 timer_expires = icsk->icsk_timeout; 1863 } else if (timer_pending(&sp->sk_timer)) { 1864 timer_active = 2; 1865 timer_expires = sp->sk_timer.expires; 1866 } else { 1867 timer_active = 0; 1868 timer_expires = jiffies; 1869 } 1870 1871 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 1872 "%08X %5d %8d %lu %d %p %u %u %u %u %d", 1873 i, src, srcp, dest, destp, sp->sk_state, 1874 tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq, 1875 timer_active, 1876 jiffies_to_clock_t(timer_expires - jiffies), 1877 icsk->icsk_retransmits, 1878 sock_i_uid(sp), 1879 icsk->icsk_probes_out, 1880 sock_i_ino(sp), 1881 atomic_read(&sp->sk_refcnt), sp, 1882 icsk->icsk_rto, 1883 icsk->icsk_ack.ato, 1884 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, 1885 tp->snd_cwnd, 1886 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh); 1887} 1888 1889static void get_timewait4_sock(struct inet_timewait_sock *tw, char *tmpbuf, int i) 1890{ 1891 unsigned int dest, src; 1892 __u16 destp, srcp; 1893 int ttd = tw->tw_ttd - jiffies; 1894 1895 if (ttd < 0) 1896 ttd = 0; 1897 1898 dest = tw->tw_daddr; 1899 src = tw->tw_rcv_saddr; 1900 destp = ntohs(tw->tw_dport); 1901 srcp = ntohs(tw->tw_sport); 1902 1903 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X" 1904 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p", 1905 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 1906 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0, 1907 atomic_read(&tw->tw_refcnt), tw); 1908} 1909 1910#define TMPSZ 150 1911 1912static int tcp4_seq_show(struct seq_file *seq, void *v) 1913{ 1914 struct tcp_iter_state* st; 1915 char tmpbuf[TMPSZ + 1]; 1916 1917 if (v == SEQ_START_TOKEN) { 1918 seq_printf(seq, "%-*s\n", TMPSZ - 1, 1919 " sl local_address rem_address st tx_queue " 1920 "rx_queue tr tm->when retrnsmt uid timeout " 1921 "inode"); 1922 goto out; 1923 } 1924 st = seq->private; 1925 1926 switch (st->state) { 1927 case TCP_SEQ_STATE_LISTENING: 1928 case TCP_SEQ_STATE_ESTABLISHED: 1929 get_tcp4_sock(v, tmpbuf, st->num); 1930 break; 1931 case TCP_SEQ_STATE_OPENREQ: 1932 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid); 1933 break; 1934 case TCP_SEQ_STATE_TIME_WAIT: 1935 get_timewait4_sock(v, tmpbuf, st->num); 1936 break; 1937 } 1938 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf); 1939out: 1940 return 0; 1941} 1942 1943static struct file_operations tcp4_seq_fops; 1944static struct tcp_seq_afinfo tcp4_seq_afinfo = { 1945 .owner = THIS_MODULE, 1946 .name = "tcp", 1947 .family = AF_INET, 1948 .seq_show = tcp4_seq_show, 1949 .seq_fops = &tcp4_seq_fops, 1950}; 1951 1952int __init tcp4_proc_init(void) 1953{ 1954 return tcp_proc_register(&tcp4_seq_afinfo); 1955} 1956 1957void tcp4_proc_exit(void) 1958{ 1959 tcp_proc_unregister(&tcp4_seq_afinfo); 1960} 1961#endif /* CONFIG_PROC_FS */ 1962 1963struct proto tcp_prot = { 1964 .name = "TCP", 1965 .owner = THIS_MODULE, 1966 .close = tcp_close, 1967 .connect = tcp_v4_connect, 1968 .disconnect = tcp_disconnect, 1969 .accept = inet_csk_accept, 1970 .ioctl = tcp_ioctl, 1971 .init = tcp_v4_init_sock, 1972 .destroy = tcp_v4_destroy_sock, 1973 .shutdown = tcp_shutdown, 1974 .setsockopt = tcp_setsockopt, 1975 .getsockopt = tcp_getsockopt, 1976 .sendmsg = tcp_sendmsg, 1977 .recvmsg = tcp_recvmsg, 1978 .backlog_rcv = tcp_v4_do_rcv, 1979 .hash = tcp_v4_hash, 1980 .unhash = tcp_unhash, 1981 .get_port = tcp_v4_get_port, 1982 .enter_memory_pressure = tcp_enter_memory_pressure, 1983 .sockets_allocated = &tcp_sockets_allocated, 1984 .orphan_count = &tcp_orphan_count, 1985 .memory_allocated = &tcp_memory_allocated, 1986 .memory_pressure = &tcp_memory_pressure, 1987 .sysctl_mem = sysctl_tcp_mem, 1988 .sysctl_wmem = sysctl_tcp_wmem, 1989 .sysctl_rmem = sysctl_tcp_rmem, 1990 .max_header = MAX_TCP_HEADER, 1991 .obj_size = sizeof(struct tcp_sock), 1992 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 1993 .rsk_prot = &tcp_request_sock_ops, 1994}; 1995 1996 1997 1998void __init tcp_v4_init(struct net_proto_family *ops) 1999{ 2000 int err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_TCP, &tcp_socket); 2001 if (err < 0) 2002 panic("Failed to create the TCP control socket.\n"); 2003 tcp_socket->sk->sk_allocation = GFP_ATOMIC; 2004 inet_sk(tcp_socket->sk)->uc_ttl = -1; 2005 2006 /* Unhash it so that IP input processing does not even 2007 * see it, we do not wish this socket to see incoming 2008 * packets. 2009 */ 2010 tcp_socket->sk->sk_prot->unhash(tcp_socket->sk); 2011} 2012 2013EXPORT_SYMBOL(ipv4_specific); 2014EXPORT_SYMBOL(inet_bind_bucket_create); 2015EXPORT_SYMBOL(tcp_hashinfo); 2016EXPORT_SYMBOL(tcp_prot); 2017EXPORT_SYMBOL(tcp_unhash); 2018EXPORT_SYMBOL(tcp_v4_conn_request); 2019EXPORT_SYMBOL(tcp_v4_connect); 2020EXPORT_SYMBOL(tcp_v4_do_rcv); 2021EXPORT_SYMBOL(tcp_v4_remember_stamp); 2022EXPORT_SYMBOL(tcp_v4_send_check); 2023EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 2024 2025#ifdef CONFIG_PROC_FS 2026EXPORT_SYMBOL(tcp_proc_register); 2027EXPORT_SYMBOL(tcp_proc_unregister); 2028#endif 2029EXPORT_SYMBOL(sysctl_local_port_range); 2030EXPORT_SYMBOL(sysctl_tcp_low_latency); 2031EXPORT_SYMBOL(sysctl_tcp_tw_reuse); 2032 2033