tcp_ipv4.c revision 81c3d5470ecc70564eb9209946730fe2be93ad06
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 .portalloc_lock = SPIN_LOCK_UNLOCKED, 97 .port_rover = 1024 - 1, 98}; 99 100static int tcp_v4_get_port(struct sock *sk, unsigned short snum) 101{ 102 return inet_csk_get_port(&tcp_hashinfo, sk, snum); 103} 104 105static void tcp_v4_hash(struct sock *sk) 106{ 107 inet_hash(&tcp_hashinfo, sk); 108} 109 110void tcp_unhash(struct sock *sk) 111{ 112 inet_unhash(&tcp_hashinfo, sk); 113} 114 115static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb) 116{ 117 return secure_tcp_sequence_number(skb->nh.iph->daddr, 118 skb->nh.iph->saddr, 119 skb->h.th->dest, 120 skb->h.th->source); 121} 122 123/* called with local bh disabled */ 124static int __tcp_v4_check_established(struct sock *sk, __u16 lport, 125 struct inet_timewait_sock **twp) 126{ 127 struct inet_sock *inet = inet_sk(sk); 128 u32 daddr = inet->rcv_saddr; 129 u32 saddr = inet->daddr; 130 int dif = sk->sk_bound_dev_if; 131 INET_ADDR_COOKIE(acookie, saddr, daddr) 132 const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport); 133 unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport); 134 struct inet_ehash_bucket *head = inet_ehash_bucket(&tcp_hashinfo, hash); 135 struct sock *sk2; 136 const struct hlist_node *node; 137 struct inet_timewait_sock *tw; 138 139 prefetch(head->chain.first); 140 write_lock(&head->lock); 141 142 /* Check TIME-WAIT sockets first. */ 143 sk_for_each(sk2, node, &(head + tcp_hashinfo.ehash_size)->chain) { 144 tw = inet_twsk(sk2); 145 146 if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) { 147 const struct tcp_timewait_sock *tcptw = tcp_twsk(sk2); 148 struct tcp_sock *tp = tcp_sk(sk); 149 150 /* With PAWS, it is safe from the viewpoint 151 of data integrity. Even without PAWS it 152 is safe provided sequence spaces do not 153 overlap i.e. at data rates <= 80Mbit/sec. 154 155 Actually, the idea is close to VJ's one, 156 only timestamp cache is held not per host, 157 but per port pair and TW bucket is used 158 as state holder. 159 160 If TW bucket has been already destroyed we 161 fall back to VJ's scheme and use initial 162 timestamp retrieved from peer table. 163 */ 164 if (tcptw->tw_ts_recent_stamp && 165 (!twp || (sysctl_tcp_tw_reuse && 166 xtime.tv_sec - 167 tcptw->tw_ts_recent_stamp > 1))) { 168 tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; 169 if (tp->write_seq == 0) 170 tp->write_seq = 1; 171 tp->rx_opt.ts_recent = tcptw->tw_ts_recent; 172 tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; 173 sock_hold(sk2); 174 goto unique; 175 } else 176 goto not_unique; 177 } 178 } 179 tw = NULL; 180 181 /* And established part... */ 182 sk_for_each(sk2, node, &head->chain) { 183 if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) 184 goto not_unique; 185 } 186 187unique: 188 /* Must record num and sport now. Otherwise we will see 189 * in hash table socket with a funny identity. */ 190 inet->num = lport; 191 inet->sport = htons(lport); 192 sk->sk_hash = hash; 193 BUG_TRAP(sk_unhashed(sk)); 194 __sk_add_node(sk, &head->chain); 195 sock_prot_inc_use(sk->sk_prot); 196 write_unlock(&head->lock); 197 198 if (twp) { 199 *twp = tw; 200 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 201 } else if (tw) { 202 /* Silly. Should hash-dance instead... */ 203 inet_twsk_deschedule(tw, &tcp_death_row); 204 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 205 206 inet_twsk_put(tw); 207 } 208 209 return 0; 210 211not_unique: 212 write_unlock(&head->lock); 213 return -EADDRNOTAVAIL; 214} 215 216static inline u32 connect_port_offset(const struct sock *sk) 217{ 218 const struct inet_sock *inet = inet_sk(sk); 219 220 return secure_tcp_port_ephemeral(inet->rcv_saddr, inet->daddr, 221 inet->dport); 222} 223 224/* 225 * Bind a port for a connect operation and hash it. 226 */ 227static inline int tcp_v4_hash_connect(struct sock *sk) 228{ 229 const unsigned short snum = inet_sk(sk)->num; 230 struct inet_bind_hashbucket *head; 231 struct inet_bind_bucket *tb; 232 int ret; 233 234 if (!snum) { 235 int low = sysctl_local_port_range[0]; 236 int high = sysctl_local_port_range[1]; 237 int range = high - low; 238 int i; 239 int port; 240 static u32 hint; 241 u32 offset = hint + connect_port_offset(sk); 242 struct hlist_node *node; 243 struct inet_timewait_sock *tw = NULL; 244 245 local_bh_disable(); 246 for (i = 1; i <= range; i++) { 247 port = low + (i + offset) % range; 248 head = &tcp_hashinfo.bhash[inet_bhashfn(port, tcp_hashinfo.bhash_size)]; 249 spin_lock(&head->lock); 250 251 /* Does not bother with rcv_saddr checks, 252 * because the established check is already 253 * unique enough. 254 */ 255 inet_bind_bucket_for_each(tb, node, &head->chain) { 256 if (tb->port == port) { 257 BUG_TRAP(!hlist_empty(&tb->owners)); 258 if (tb->fastreuse >= 0) 259 goto next_port; 260 if (!__tcp_v4_check_established(sk, 261 port, 262 &tw)) 263 goto ok; 264 goto next_port; 265 } 266 } 267 268 tb = inet_bind_bucket_create(tcp_hashinfo.bind_bucket_cachep, head, port); 269 if (!tb) { 270 spin_unlock(&head->lock); 271 break; 272 } 273 tb->fastreuse = -1; 274 goto ok; 275 276 next_port: 277 spin_unlock(&head->lock); 278 } 279 local_bh_enable(); 280 281 return -EADDRNOTAVAIL; 282 283ok: 284 hint += i; 285 286 /* Head lock still held and bh's disabled */ 287 inet_bind_hash(sk, tb, port); 288 if (sk_unhashed(sk)) { 289 inet_sk(sk)->sport = htons(port); 290 __inet_hash(&tcp_hashinfo, sk, 0); 291 } 292 spin_unlock(&head->lock); 293 294 if (tw) { 295 inet_twsk_deschedule(tw, &tcp_death_row);; 296 inet_twsk_put(tw); 297 } 298 299 ret = 0; 300 goto out; 301 } 302 303 head = &tcp_hashinfo.bhash[inet_bhashfn(snum, tcp_hashinfo.bhash_size)]; 304 tb = inet_csk(sk)->icsk_bind_hash; 305 spin_lock_bh(&head->lock); 306 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { 307 __inet_hash(&tcp_hashinfo, sk, 0); 308 spin_unlock_bh(&head->lock); 309 return 0; 310 } else { 311 spin_unlock(&head->lock); 312 /* No definite answer... Walk to established hash table */ 313 ret = __tcp_v4_check_established(sk, snum, NULL); 314out: 315 local_bh_enable(); 316 return ret; 317 } 318} 319 320/* This will initiate an outgoing connection. */ 321int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 322{ 323 struct inet_sock *inet = inet_sk(sk); 324 struct tcp_sock *tp = tcp_sk(sk); 325 struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; 326 struct rtable *rt; 327 u32 daddr, nexthop; 328 int tmp; 329 int err; 330 331 if (addr_len < sizeof(struct sockaddr_in)) 332 return -EINVAL; 333 334 if (usin->sin_family != AF_INET) 335 return -EAFNOSUPPORT; 336 337 nexthop = daddr = usin->sin_addr.s_addr; 338 if (inet->opt && inet->opt->srr) { 339 if (!daddr) 340 return -EINVAL; 341 nexthop = inet->opt->faddr; 342 } 343 344 tmp = ip_route_connect(&rt, nexthop, inet->saddr, 345 RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, 346 IPPROTO_TCP, 347 inet->sport, usin->sin_port, sk); 348 if (tmp < 0) 349 return tmp; 350 351 if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { 352 ip_rt_put(rt); 353 return -ENETUNREACH; 354 } 355 356 if (!inet->opt || !inet->opt->srr) 357 daddr = rt->rt_dst; 358 359 if (!inet->saddr) 360 inet->saddr = rt->rt_src; 361 inet->rcv_saddr = inet->saddr; 362 363 if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) { 364 /* Reset inherited state */ 365 tp->rx_opt.ts_recent = 0; 366 tp->rx_opt.ts_recent_stamp = 0; 367 tp->write_seq = 0; 368 } 369 370 if (tcp_death_row.sysctl_tw_recycle && 371 !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) { 372 struct inet_peer *peer = rt_get_peer(rt); 373 374 /* VJ's idea. We save last timestamp seen from 375 * the destination in peer table, when entering state TIME-WAIT 376 * and initialize rx_opt.ts_recent from it, when trying new connection. 377 */ 378 379 if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) { 380 tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp; 381 tp->rx_opt.ts_recent = peer->tcp_ts; 382 } 383 } 384 385 inet->dport = usin->sin_port; 386 inet->daddr = daddr; 387 388 tp->ext_header_len = 0; 389 if (inet->opt) 390 tp->ext_header_len = inet->opt->optlen; 391 392 tp->rx_opt.mss_clamp = 536; 393 394 /* Socket identity is still unknown (sport may be zero). 395 * However we set state to SYN-SENT and not releasing socket 396 * lock select source port, enter ourselves into the hash tables and 397 * complete initialization after this. 398 */ 399 tcp_set_state(sk, TCP_SYN_SENT); 400 err = tcp_v4_hash_connect(sk); 401 if (err) 402 goto failure; 403 404 err = ip_route_newports(&rt, inet->sport, inet->dport, sk); 405 if (err) 406 goto failure; 407 408 /* OK, now commit destination to socket. */ 409 sk_setup_caps(sk, &rt->u.dst); 410 411 if (!tp->write_seq) 412 tp->write_seq = secure_tcp_sequence_number(inet->saddr, 413 inet->daddr, 414 inet->sport, 415 usin->sin_port); 416 417 inet->id = tp->write_seq ^ jiffies; 418 419 err = tcp_connect(sk); 420 rt = NULL; 421 if (err) 422 goto failure; 423 424 return 0; 425 426failure: 427 /* This unhashes the socket and releases the local port, if necessary. */ 428 tcp_set_state(sk, TCP_CLOSE); 429 ip_rt_put(rt); 430 sk->sk_route_caps = 0; 431 inet->dport = 0; 432 return err; 433} 434 435/* 436 * This routine does path mtu discovery as defined in RFC1191. 437 */ 438static inline void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, 439 u32 mtu) 440{ 441 struct dst_entry *dst; 442 struct inet_sock *inet = inet_sk(sk); 443 struct tcp_sock *tp = tcp_sk(sk); 444 445 /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs 446 * send out by Linux are always <576bytes so they should go through 447 * unfragmented). 448 */ 449 if (sk->sk_state == TCP_LISTEN) 450 return; 451 452 /* We don't check in the destentry if pmtu discovery is forbidden 453 * on this route. We just assume that no packet_to_big packets 454 * are send back when pmtu discovery is not active. 455 * There is a small race when the user changes this flag in the 456 * route, but I think that's acceptable. 457 */ 458 if ((dst = __sk_dst_check(sk, 0)) == NULL) 459 return; 460 461 dst->ops->update_pmtu(dst, mtu); 462 463 /* Something is about to be wrong... Remember soft error 464 * for the case, if this connection will not able to recover. 465 */ 466 if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) 467 sk->sk_err_soft = EMSGSIZE; 468 469 mtu = dst_mtu(dst); 470 471 if (inet->pmtudisc != IP_PMTUDISC_DONT && 472 tp->pmtu_cookie > mtu) { 473 tcp_sync_mss(sk, mtu); 474 475 /* Resend the TCP packet because it's 476 * clear that the old packet has been 477 * dropped. This is the new "fast" path mtu 478 * discovery. 479 */ 480 tcp_simple_retransmit(sk); 481 } /* else let the usual retransmit timer handle it */ 482} 483 484/* 485 * This routine is called by the ICMP module when it gets some 486 * sort of error condition. If err < 0 then the socket should 487 * be closed and the error returned to the user. If err > 0 488 * it's just the icmp type << 8 | icmp code. After adjustment 489 * header points to the first 8 bytes of the tcp header. We need 490 * to find the appropriate port. 491 * 492 * The locking strategy used here is very "optimistic". When 493 * someone else accesses the socket the ICMP is just dropped 494 * and for some paths there is no check at all. 495 * A more general error queue to queue errors for later handling 496 * is probably better. 497 * 498 */ 499 500void tcp_v4_err(struct sk_buff *skb, u32 info) 501{ 502 struct iphdr *iph = (struct iphdr *)skb->data; 503 struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2)); 504 struct tcp_sock *tp; 505 struct inet_sock *inet; 506 int type = skb->h.icmph->type; 507 int code = skb->h.icmph->code; 508 struct sock *sk; 509 __u32 seq; 510 int err; 511 512 if (skb->len < (iph->ihl << 2) + 8) { 513 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 514 return; 515 } 516 517 sk = inet_lookup(&tcp_hashinfo, iph->daddr, th->dest, iph->saddr, 518 th->source, inet_iif(skb)); 519 if (!sk) { 520 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 521 return; 522 } 523 if (sk->sk_state == TCP_TIME_WAIT) { 524 inet_twsk_put((struct inet_timewait_sock *)sk); 525 return; 526 } 527 528 bh_lock_sock(sk); 529 /* If too many ICMPs get dropped on busy 530 * servers this needs to be solved differently. 531 */ 532 if (sock_owned_by_user(sk)) 533 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); 534 535 if (sk->sk_state == TCP_CLOSE) 536 goto out; 537 538 tp = tcp_sk(sk); 539 seq = ntohl(th->seq); 540 if (sk->sk_state != TCP_LISTEN && 541 !between(seq, tp->snd_una, tp->snd_nxt)) { 542 NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS); 543 goto out; 544 } 545 546 switch (type) { 547 case ICMP_SOURCE_QUENCH: 548 /* Just silently ignore these. */ 549 goto out; 550 case ICMP_PARAMETERPROB: 551 err = EPROTO; 552 break; 553 case ICMP_DEST_UNREACH: 554 if (code > NR_ICMP_UNREACH) 555 goto out; 556 557 if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ 558 if (!sock_owned_by_user(sk)) 559 do_pmtu_discovery(sk, iph, info); 560 goto out; 561 } 562 563 err = icmp_err_convert[code].errno; 564 break; 565 case ICMP_TIME_EXCEEDED: 566 err = EHOSTUNREACH; 567 break; 568 default: 569 goto out; 570 } 571 572 switch (sk->sk_state) { 573 struct request_sock *req, **prev; 574 case TCP_LISTEN: 575 if (sock_owned_by_user(sk)) 576 goto out; 577 578 req = inet_csk_search_req(sk, &prev, th->dest, 579 iph->daddr, iph->saddr); 580 if (!req) 581 goto out; 582 583 /* ICMPs are not backlogged, hence we cannot get 584 an established socket here. 585 */ 586 BUG_TRAP(!req->sk); 587 588 if (seq != tcp_rsk(req)->snt_isn) { 589 NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS); 590 goto out; 591 } 592 593 /* 594 * Still in SYN_RECV, just remove it silently. 595 * There is no good way to pass the error to the newly 596 * created socket, and POSIX does not want network 597 * errors returned from accept(). 598 */ 599 inet_csk_reqsk_queue_drop(sk, req, prev); 600 goto out; 601 602 case TCP_SYN_SENT: 603 case TCP_SYN_RECV: /* Cannot happen. 604 It can f.e. if SYNs crossed. 605 */ 606 if (!sock_owned_by_user(sk)) { 607 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); 608 sk->sk_err = err; 609 610 sk->sk_error_report(sk); 611 612 tcp_done(sk); 613 } else { 614 sk->sk_err_soft = err; 615 } 616 goto out; 617 } 618 619 /* If we've already connected we will keep trying 620 * until we time out, or the user gives up. 621 * 622 * rfc1122 4.2.3.9 allows to consider as hard errors 623 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, 624 * but it is obsoleted by pmtu discovery). 625 * 626 * Note, that in modern internet, where routing is unreliable 627 * and in each dark corner broken firewalls sit, sending random 628 * errors ordered by their masters even this two messages finally lose 629 * their original sense (even Linux sends invalid PORT_UNREACHs) 630 * 631 * Now we are in compliance with RFCs. 632 * --ANK (980905) 633 */ 634 635 inet = inet_sk(sk); 636 if (!sock_owned_by_user(sk) && inet->recverr) { 637 sk->sk_err = err; 638 sk->sk_error_report(sk); 639 } else { /* Only an error on timeout */ 640 sk->sk_err_soft = err; 641 } 642 643out: 644 bh_unlock_sock(sk); 645 sock_put(sk); 646} 647 648/* This routine computes an IPv4 TCP checksum. */ 649void tcp_v4_send_check(struct sock *sk, struct tcphdr *th, int len, 650 struct sk_buff *skb) 651{ 652 struct inet_sock *inet = inet_sk(sk); 653 654 if (skb->ip_summed == CHECKSUM_HW) { 655 th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0); 656 skb->csum = offsetof(struct tcphdr, check); 657 } else { 658 th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr, 659 csum_partial((char *)th, 660 th->doff << 2, 661 skb->csum)); 662 } 663} 664 665/* 666 * This routine will send an RST to the other tcp. 667 * 668 * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) 669 * for reset. 670 * Answer: if a packet caused RST, it is not for a socket 671 * existing in our system, if it is matched to a socket, 672 * it is just duplicate segment or bug in other side's TCP. 673 * So that we build reply only basing on parameters 674 * arrived with segment. 675 * Exception: precedence violation. We do not implement it in any case. 676 */ 677 678static void tcp_v4_send_reset(struct sk_buff *skb) 679{ 680 struct tcphdr *th = skb->h.th; 681 struct tcphdr rth; 682 struct ip_reply_arg arg; 683 684 /* Never send a reset in response to a reset. */ 685 if (th->rst) 686 return; 687 688 if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL) 689 return; 690 691 /* Swap the send and the receive. */ 692 memset(&rth, 0, sizeof(struct tcphdr)); 693 rth.dest = th->source; 694 rth.source = th->dest; 695 rth.doff = sizeof(struct tcphdr) / 4; 696 rth.rst = 1; 697 698 if (th->ack) { 699 rth.seq = th->ack_seq; 700 } else { 701 rth.ack = 1; 702 rth.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + 703 skb->len - (th->doff << 2)); 704 } 705 706 memset(&arg, 0, sizeof arg); 707 arg.iov[0].iov_base = (unsigned char *)&rth; 708 arg.iov[0].iov_len = sizeof rth; 709 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr, 710 skb->nh.iph->saddr, /*XXX*/ 711 sizeof(struct tcphdr), IPPROTO_TCP, 0); 712 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 713 714 ip_send_reply(tcp_socket->sk, skb, &arg, sizeof rth); 715 716 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS); 717 TCP_INC_STATS_BH(TCP_MIB_OUTRSTS); 718} 719 720/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states 721 outside socket context is ugly, certainly. What can I do? 722 */ 723 724static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, 725 u32 win, u32 ts) 726{ 727 struct tcphdr *th = skb->h.th; 728 struct { 729 struct tcphdr th; 730 u32 tsopt[3]; 731 } rep; 732 struct ip_reply_arg arg; 733 734 memset(&rep.th, 0, sizeof(struct tcphdr)); 735 memset(&arg, 0, sizeof arg); 736 737 arg.iov[0].iov_base = (unsigned char *)&rep; 738 arg.iov[0].iov_len = sizeof(rep.th); 739 if (ts) { 740 rep.tsopt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 741 (TCPOPT_TIMESTAMP << 8) | 742 TCPOLEN_TIMESTAMP); 743 rep.tsopt[1] = htonl(tcp_time_stamp); 744 rep.tsopt[2] = htonl(ts); 745 arg.iov[0].iov_len = sizeof(rep); 746 } 747 748 /* Swap the send and the receive. */ 749 rep.th.dest = th->source; 750 rep.th.source = th->dest; 751 rep.th.doff = arg.iov[0].iov_len / 4; 752 rep.th.seq = htonl(seq); 753 rep.th.ack_seq = htonl(ack); 754 rep.th.ack = 1; 755 rep.th.window = htons(win); 756 757 arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr, 758 skb->nh.iph->saddr, /*XXX*/ 759 arg.iov[0].iov_len, IPPROTO_TCP, 0); 760 arg.csumoffset = offsetof(struct tcphdr, check) / 2; 761 762 ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len); 763 764 TCP_INC_STATS_BH(TCP_MIB_OUTSEGS); 765} 766 767static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 768{ 769 struct inet_timewait_sock *tw = inet_twsk(sk); 770 const struct tcp_timewait_sock *tcptw = tcp_twsk(sk); 771 772 tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, 773 tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcptw->tw_ts_recent); 774 775 inet_twsk_put(tw); 776} 777 778static void tcp_v4_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req) 779{ 780 tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, 781 req->ts_recent); 782} 783 784/* 785 * Send a SYN-ACK after having received an ACK. 786 * This still operates on a request_sock only, not on a big 787 * socket. 788 */ 789static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req, 790 struct dst_entry *dst) 791{ 792 const struct inet_request_sock *ireq = inet_rsk(req); 793 int err = -1; 794 struct sk_buff * skb; 795 796 /* First, grab a route. */ 797 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL) 798 goto out; 799 800 skb = tcp_make_synack(sk, dst, req); 801 802 if (skb) { 803 struct tcphdr *th = skb->h.th; 804 805 th->check = tcp_v4_check(th, skb->len, 806 ireq->loc_addr, 807 ireq->rmt_addr, 808 csum_partial((char *)th, skb->len, 809 skb->csum)); 810 811 err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, 812 ireq->rmt_addr, 813 ireq->opt); 814 if (err == NET_XMIT_CN) 815 err = 0; 816 } 817 818out: 819 dst_release(dst); 820 return err; 821} 822 823/* 824 * IPv4 request_sock destructor. 825 */ 826static void tcp_v4_reqsk_destructor(struct request_sock *req) 827{ 828 if (inet_rsk(req)->opt) 829 kfree(inet_rsk(req)->opt); 830} 831 832static inline void syn_flood_warning(struct sk_buff *skb) 833{ 834 static unsigned long warntime; 835 836 if (time_after(jiffies, (warntime + HZ * 60))) { 837 warntime = jiffies; 838 printk(KERN_INFO 839 "possible SYN flooding on port %d. Sending cookies.\n", 840 ntohs(skb->h.th->dest)); 841 } 842} 843 844/* 845 * Save and compile IPv4 options into the request_sock if needed. 846 */ 847static inline struct ip_options *tcp_v4_save_options(struct sock *sk, 848 struct sk_buff *skb) 849{ 850 struct ip_options *opt = &(IPCB(skb)->opt); 851 struct ip_options *dopt = NULL; 852 853 if (opt && opt->optlen) { 854 int opt_size = optlength(opt); 855 dopt = kmalloc(opt_size, GFP_ATOMIC); 856 if (dopt) { 857 if (ip_options_echo(dopt, skb)) { 858 kfree(dopt); 859 dopt = NULL; 860 } 861 } 862 } 863 return dopt; 864} 865 866struct request_sock_ops tcp_request_sock_ops = { 867 .family = PF_INET, 868 .obj_size = sizeof(struct tcp_request_sock), 869 .rtx_syn_ack = tcp_v4_send_synack, 870 .send_ack = tcp_v4_reqsk_send_ack, 871 .destructor = tcp_v4_reqsk_destructor, 872 .send_reset = tcp_v4_send_reset, 873}; 874 875int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) 876{ 877 struct inet_request_sock *ireq; 878 struct tcp_options_received tmp_opt; 879 struct request_sock *req; 880 __u32 saddr = skb->nh.iph->saddr; 881 __u32 daddr = skb->nh.iph->daddr; 882 __u32 isn = TCP_SKB_CB(skb)->when; 883 struct dst_entry *dst = NULL; 884#ifdef CONFIG_SYN_COOKIES 885 int want_cookie = 0; 886#else 887#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */ 888#endif 889 890 /* Never answer to SYNs send to broadcast or multicast */ 891 if (((struct rtable *)skb->dst)->rt_flags & 892 (RTCF_BROADCAST | RTCF_MULTICAST)) 893 goto drop; 894 895 /* TW buckets are converted to open requests without 896 * limitations, they conserve resources and peer is 897 * evidently real one. 898 */ 899 if (inet_csk_reqsk_queue_is_full(sk) && !isn) { 900#ifdef CONFIG_SYN_COOKIES 901 if (sysctl_tcp_syncookies) { 902 want_cookie = 1; 903 } else 904#endif 905 goto drop; 906 } 907 908 /* Accept backlog is full. If we have already queued enough 909 * of warm entries in syn queue, drop request. It is better than 910 * clogging syn queue with openreqs with exponentially increasing 911 * timeout. 912 */ 913 if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) 914 goto drop; 915 916 req = reqsk_alloc(&tcp_request_sock_ops); 917 if (!req) 918 goto drop; 919 920 tcp_clear_options(&tmp_opt); 921 tmp_opt.mss_clamp = 536; 922 tmp_opt.user_mss = tcp_sk(sk)->rx_opt.user_mss; 923 924 tcp_parse_options(skb, &tmp_opt, 0); 925 926 if (want_cookie) { 927 tcp_clear_options(&tmp_opt); 928 tmp_opt.saw_tstamp = 0; 929 } 930 931 if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) { 932 /* Some OSes (unknown ones, but I see them on web server, which 933 * contains information interesting only for windows' 934 * users) do not send their stamp in SYN. It is easy case. 935 * We simply do not advertise TS support. 936 */ 937 tmp_opt.saw_tstamp = 0; 938 tmp_opt.tstamp_ok = 0; 939 } 940 tmp_opt.tstamp_ok = tmp_opt.saw_tstamp; 941 942 tcp_openreq_init(req, &tmp_opt, skb); 943 944 ireq = inet_rsk(req); 945 ireq->loc_addr = daddr; 946 ireq->rmt_addr = saddr; 947 ireq->opt = tcp_v4_save_options(sk, skb); 948 if (!want_cookie) 949 TCP_ECN_create_request(req, skb->h.th); 950 951 if (want_cookie) { 952#ifdef CONFIG_SYN_COOKIES 953 syn_flood_warning(skb); 954#endif 955 isn = cookie_v4_init_sequence(sk, skb, &req->mss); 956 } else if (!isn) { 957 struct inet_peer *peer = NULL; 958 959 /* VJ's idea. We save last timestamp seen 960 * from the destination in peer table, when entering 961 * state TIME-WAIT, and check against it before 962 * accepting new connection request. 963 * 964 * If "isn" is not zero, this request hit alive 965 * timewait bucket, so that all the necessary checks 966 * are made in the function processing timewait state. 967 */ 968 if (tmp_opt.saw_tstamp && 969 tcp_death_row.sysctl_tw_recycle && 970 (dst = inet_csk_route_req(sk, req)) != NULL && 971 (peer = rt_get_peer((struct rtable *)dst)) != NULL && 972 peer->v4daddr == saddr) { 973 if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL && 974 (s32)(peer->tcp_ts - req->ts_recent) > 975 TCP_PAWS_WINDOW) { 976 NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED); 977 dst_release(dst); 978 goto drop_and_free; 979 } 980 } 981 /* Kill the following clause, if you dislike this way. */ 982 else if (!sysctl_tcp_syncookies && 983 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) < 984 (sysctl_max_syn_backlog >> 2)) && 985 (!peer || !peer->tcp_ts_stamp) && 986 (!dst || !dst_metric(dst, RTAX_RTT))) { 987 /* Without syncookies last quarter of 988 * backlog is filled with destinations, 989 * proven to be alive. 990 * It means that we continue to communicate 991 * to destinations, already remembered 992 * to the moment of synflood. 993 */ 994 LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open " 995 "request from %u.%u.%u.%u/%u\n", 996 NIPQUAD(saddr), 997 ntohs(skb->h.th->source)); 998 dst_release(dst); 999 goto drop_and_free; 1000 } 1001 1002 isn = tcp_v4_init_sequence(sk, skb); 1003 } 1004 tcp_rsk(req)->snt_isn = isn; 1005 1006 if (tcp_v4_send_synack(sk, req, dst)) 1007 goto drop_and_free; 1008 1009 if (want_cookie) { 1010 reqsk_free(req); 1011 } else { 1012 inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT); 1013 } 1014 return 0; 1015 1016drop_and_free: 1017 reqsk_free(req); 1018drop: 1019 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); 1020 return 0; 1021} 1022 1023 1024/* 1025 * The three way handshake has completed - we got a valid synack - 1026 * now create the new socket. 1027 */ 1028struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, 1029 struct request_sock *req, 1030 struct dst_entry *dst) 1031{ 1032 struct inet_request_sock *ireq; 1033 struct inet_sock *newinet; 1034 struct tcp_sock *newtp; 1035 struct sock *newsk; 1036 1037 if (sk_acceptq_is_full(sk)) 1038 goto exit_overflow; 1039 1040 if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL) 1041 goto exit; 1042 1043 newsk = tcp_create_openreq_child(sk, req, skb); 1044 if (!newsk) 1045 goto exit; 1046 1047 sk_setup_caps(newsk, dst); 1048 1049 newtp = tcp_sk(newsk); 1050 newinet = inet_sk(newsk); 1051 ireq = inet_rsk(req); 1052 newinet->daddr = ireq->rmt_addr; 1053 newinet->rcv_saddr = ireq->loc_addr; 1054 newinet->saddr = ireq->loc_addr; 1055 newinet->opt = ireq->opt; 1056 ireq->opt = NULL; 1057 newinet->mc_index = inet_iif(skb); 1058 newinet->mc_ttl = skb->nh.iph->ttl; 1059 newtp->ext_header_len = 0; 1060 if (newinet->opt) 1061 newtp->ext_header_len = newinet->opt->optlen; 1062 newinet->id = newtp->write_seq ^ jiffies; 1063 1064 tcp_sync_mss(newsk, dst_mtu(dst)); 1065 newtp->advmss = dst_metric(dst, RTAX_ADVMSS); 1066 tcp_initialize_rcv_mss(newsk); 1067 1068 __inet_hash(&tcp_hashinfo, newsk, 0); 1069 __inet_inherit_port(&tcp_hashinfo, sk, newsk); 1070 1071 return newsk; 1072 1073exit_overflow: 1074 NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS); 1075exit: 1076 NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS); 1077 dst_release(dst); 1078 return NULL; 1079} 1080 1081static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb) 1082{ 1083 struct tcphdr *th = skb->h.th; 1084 struct iphdr *iph = skb->nh.iph; 1085 struct sock *nsk; 1086 struct request_sock **prev; 1087 /* Find possible connection requests. */ 1088 struct request_sock *req = inet_csk_search_req(sk, &prev, th->source, 1089 iph->saddr, iph->daddr); 1090 if (req) 1091 return tcp_check_req(sk, skb, req, prev); 1092 1093 nsk = __inet_lookup_established(&tcp_hashinfo, skb->nh.iph->saddr, 1094 th->source, skb->nh.iph->daddr, 1095 ntohs(th->dest), inet_iif(skb)); 1096 1097 if (nsk) { 1098 if (nsk->sk_state != TCP_TIME_WAIT) { 1099 bh_lock_sock(nsk); 1100 return nsk; 1101 } 1102 inet_twsk_put((struct inet_timewait_sock *)nsk); 1103 return NULL; 1104 } 1105 1106#ifdef CONFIG_SYN_COOKIES 1107 if (!th->rst && !th->syn && th->ack) 1108 sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt)); 1109#endif 1110 return sk; 1111} 1112 1113static int tcp_v4_checksum_init(struct sk_buff *skb) 1114{ 1115 if (skb->ip_summed == CHECKSUM_HW) { 1116 skb->ip_summed = CHECKSUM_UNNECESSARY; 1117 if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr, 1118 skb->nh.iph->daddr, skb->csum)) 1119 return 0; 1120 1121 LIMIT_NETDEBUG(KERN_DEBUG "hw tcp v4 csum failed\n"); 1122 skb->ip_summed = CHECKSUM_NONE; 1123 } 1124 if (skb->len <= 76) { 1125 if (tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr, 1126 skb->nh.iph->daddr, 1127 skb_checksum(skb, 0, skb->len, 0))) 1128 return -1; 1129 skb->ip_summed = CHECKSUM_UNNECESSARY; 1130 } else { 1131 skb->csum = ~tcp_v4_check(skb->h.th, skb->len, 1132 skb->nh.iph->saddr, 1133 skb->nh.iph->daddr, 0); 1134 } 1135 return 0; 1136} 1137 1138 1139/* The socket must have it's spinlock held when we get 1140 * here. 1141 * 1142 * We have a potential double-lock case here, so even when 1143 * doing backlog processing we use the BH locking scheme. 1144 * This is because we cannot sleep with the original spinlock 1145 * held. 1146 */ 1147int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 1148{ 1149 if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ 1150 TCP_CHECK_TIMER(sk); 1151 if (tcp_rcv_established(sk, skb, skb->h.th, skb->len)) 1152 goto reset; 1153 TCP_CHECK_TIMER(sk); 1154 return 0; 1155 } 1156 1157 if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb)) 1158 goto csum_err; 1159 1160 if (sk->sk_state == TCP_LISTEN) { 1161 struct sock *nsk = tcp_v4_hnd_req(sk, skb); 1162 if (!nsk) 1163 goto discard; 1164 1165 if (nsk != sk) { 1166 if (tcp_child_process(sk, nsk, skb)) 1167 goto reset; 1168 return 0; 1169 } 1170 } 1171 1172 TCP_CHECK_TIMER(sk); 1173 if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len)) 1174 goto reset; 1175 TCP_CHECK_TIMER(sk); 1176 return 0; 1177 1178reset: 1179 tcp_v4_send_reset(skb); 1180discard: 1181 kfree_skb(skb); 1182 /* Be careful here. If this function gets more complicated and 1183 * gcc suffers from register pressure on the x86, sk (in %ebx) 1184 * might be destroyed here. This current version compiles correctly, 1185 * but you have been warned. 1186 */ 1187 return 0; 1188 1189csum_err: 1190 TCP_INC_STATS_BH(TCP_MIB_INERRS); 1191 goto discard; 1192} 1193 1194/* 1195 * From tcp_input.c 1196 */ 1197 1198int tcp_v4_rcv(struct sk_buff *skb) 1199{ 1200 struct tcphdr *th; 1201 struct sock *sk; 1202 int ret; 1203 1204 if (skb->pkt_type != PACKET_HOST) 1205 goto discard_it; 1206 1207 /* Count it even if it's bad */ 1208 TCP_INC_STATS_BH(TCP_MIB_INSEGS); 1209 1210 if (!pskb_may_pull(skb, sizeof(struct tcphdr))) 1211 goto discard_it; 1212 1213 th = skb->h.th; 1214 1215 if (th->doff < sizeof(struct tcphdr) / 4) 1216 goto bad_packet; 1217 if (!pskb_may_pull(skb, th->doff * 4)) 1218 goto discard_it; 1219 1220 /* An explanation is required here, I think. 1221 * Packet length and doff are validated by header prediction, 1222 * provided case of th->doff==0 is elimineted. 1223 * So, we defer the checks. */ 1224 if ((skb->ip_summed != CHECKSUM_UNNECESSARY && 1225 tcp_v4_checksum_init(skb) < 0)) 1226 goto bad_packet; 1227 1228 th = skb->h.th; 1229 TCP_SKB_CB(skb)->seq = ntohl(th->seq); 1230 TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + 1231 skb->len - th->doff * 4); 1232 TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); 1233 TCP_SKB_CB(skb)->when = 0; 1234 TCP_SKB_CB(skb)->flags = skb->nh.iph->tos; 1235 TCP_SKB_CB(skb)->sacked = 0; 1236 1237 sk = __inet_lookup(&tcp_hashinfo, skb->nh.iph->saddr, th->source, 1238 skb->nh.iph->daddr, ntohs(th->dest), 1239 inet_iif(skb)); 1240 1241 if (!sk) 1242 goto no_tcp_socket; 1243 1244process: 1245 if (sk->sk_state == TCP_TIME_WAIT) 1246 goto do_time_wait; 1247 1248 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) 1249 goto discard_and_relse; 1250 1251 if (sk_filter(sk, skb, 0)) 1252 goto discard_and_relse; 1253 1254 skb->dev = NULL; 1255 1256 bh_lock_sock(sk); 1257 ret = 0; 1258 if (!sock_owned_by_user(sk)) { 1259 if (!tcp_prequeue(sk, skb)) 1260 ret = tcp_v4_do_rcv(sk, skb); 1261 } else 1262 sk_add_backlog(sk, skb); 1263 bh_unlock_sock(sk); 1264 1265 sock_put(sk); 1266 1267 return ret; 1268 1269no_tcp_socket: 1270 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 1271 goto discard_it; 1272 1273 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { 1274bad_packet: 1275 TCP_INC_STATS_BH(TCP_MIB_INERRS); 1276 } else { 1277 tcp_v4_send_reset(skb); 1278 } 1279 1280discard_it: 1281 /* Discard frame. */ 1282 kfree_skb(skb); 1283 return 0; 1284 1285discard_and_relse: 1286 sock_put(sk); 1287 goto discard_it; 1288 1289do_time_wait: 1290 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 1291 inet_twsk_put((struct inet_timewait_sock *) sk); 1292 goto discard_it; 1293 } 1294 1295 if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { 1296 TCP_INC_STATS_BH(TCP_MIB_INERRS); 1297 inet_twsk_put((struct inet_timewait_sock *) sk); 1298 goto discard_it; 1299 } 1300 switch (tcp_timewait_state_process((struct inet_timewait_sock *)sk, 1301 skb, th)) { 1302 case TCP_TW_SYN: { 1303 struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo, 1304 skb->nh.iph->daddr, 1305 ntohs(th->dest), 1306 inet_iif(skb)); 1307 if (sk2) { 1308 inet_twsk_deschedule((struct inet_timewait_sock *)sk, 1309 &tcp_death_row); 1310 inet_twsk_put((struct inet_timewait_sock *)sk); 1311 sk = sk2; 1312 goto process; 1313 } 1314 /* Fall through to ACK */ 1315 } 1316 case TCP_TW_ACK: 1317 tcp_v4_timewait_ack(sk, skb); 1318 break; 1319 case TCP_TW_RST: 1320 goto no_tcp_socket; 1321 case TCP_TW_SUCCESS:; 1322 } 1323 goto discard_it; 1324} 1325 1326static void v4_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr) 1327{ 1328 struct sockaddr_in *sin = (struct sockaddr_in *) uaddr; 1329 struct inet_sock *inet = inet_sk(sk); 1330 1331 sin->sin_family = AF_INET; 1332 sin->sin_addr.s_addr = inet->daddr; 1333 sin->sin_port = inet->dport; 1334} 1335 1336/* VJ's idea. Save last timestamp seen from this destination 1337 * and hold it at least for normal timewait interval to use for duplicate 1338 * segment detection in subsequent connections, before they enter synchronized 1339 * state. 1340 */ 1341 1342int tcp_v4_remember_stamp(struct sock *sk) 1343{ 1344 struct inet_sock *inet = inet_sk(sk); 1345 struct tcp_sock *tp = tcp_sk(sk); 1346 struct rtable *rt = (struct rtable *)__sk_dst_get(sk); 1347 struct inet_peer *peer = NULL; 1348 int release_it = 0; 1349 1350 if (!rt || rt->rt_dst != inet->daddr) { 1351 peer = inet_getpeer(inet->daddr, 1); 1352 release_it = 1; 1353 } else { 1354 if (!rt->peer) 1355 rt_bind_peer(rt, 1); 1356 peer = rt->peer; 1357 } 1358 1359 if (peer) { 1360 if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 || 1361 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec && 1362 peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) { 1363 peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp; 1364 peer->tcp_ts = tp->rx_opt.ts_recent; 1365 } 1366 if (release_it) 1367 inet_putpeer(peer); 1368 return 1; 1369 } 1370 1371 return 0; 1372} 1373 1374int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw) 1375{ 1376 struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1); 1377 1378 if (peer) { 1379 const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw); 1380 1381 if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 || 1382 (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec && 1383 peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) { 1384 peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp; 1385 peer->tcp_ts = tcptw->tw_ts_recent; 1386 } 1387 inet_putpeer(peer); 1388 return 1; 1389 } 1390 1391 return 0; 1392} 1393 1394struct tcp_func ipv4_specific = { 1395 .queue_xmit = ip_queue_xmit, 1396 .send_check = tcp_v4_send_check, 1397 .rebuild_header = inet_sk_rebuild_header, 1398 .conn_request = tcp_v4_conn_request, 1399 .syn_recv_sock = tcp_v4_syn_recv_sock, 1400 .remember_stamp = tcp_v4_remember_stamp, 1401 .net_header_len = sizeof(struct iphdr), 1402 .setsockopt = ip_setsockopt, 1403 .getsockopt = ip_getsockopt, 1404 .addr2sockaddr = v4_addr2sockaddr, 1405 .sockaddr_len = sizeof(struct sockaddr_in), 1406}; 1407 1408/* NOTE: A lot of things set to zero explicitly by call to 1409 * sk_alloc() so need not be done here. 1410 */ 1411static int tcp_v4_init_sock(struct sock *sk) 1412{ 1413 struct inet_connection_sock *icsk = inet_csk(sk); 1414 struct tcp_sock *tp = tcp_sk(sk); 1415 1416 skb_queue_head_init(&tp->out_of_order_queue); 1417 tcp_init_xmit_timers(sk); 1418 tcp_prequeue_init(tp); 1419 1420 icsk->icsk_rto = TCP_TIMEOUT_INIT; 1421 tp->mdev = TCP_TIMEOUT_INIT; 1422 1423 /* So many TCP implementations out there (incorrectly) count the 1424 * initial SYN frame in their delayed-ACK and congestion control 1425 * algorithms that we must have the following bandaid to talk 1426 * efficiently to them. -DaveM 1427 */ 1428 tp->snd_cwnd = 2; 1429 1430 /* See draft-stevens-tcpca-spec-01 for discussion of the 1431 * initialization of these values. 1432 */ 1433 tp->snd_ssthresh = 0x7fffffff; /* Infinity */ 1434 tp->snd_cwnd_clamp = ~0; 1435 tp->mss_cache = 536; 1436 1437 tp->reordering = sysctl_tcp_reordering; 1438 icsk->icsk_ca_ops = &tcp_init_congestion_ops; 1439 1440 sk->sk_state = TCP_CLOSE; 1441 1442 sk->sk_write_space = sk_stream_write_space; 1443 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 1444 1445 tp->af_specific = &ipv4_specific; 1446 1447 sk->sk_sndbuf = sysctl_tcp_wmem[1]; 1448 sk->sk_rcvbuf = sysctl_tcp_rmem[1]; 1449 1450 atomic_inc(&tcp_sockets_allocated); 1451 1452 return 0; 1453} 1454 1455int tcp_v4_destroy_sock(struct sock *sk) 1456{ 1457 struct tcp_sock *tp = tcp_sk(sk); 1458 1459 tcp_clear_xmit_timers(sk); 1460 1461 tcp_cleanup_congestion_control(sk); 1462 1463 /* Cleanup up the write buffer. */ 1464 sk_stream_writequeue_purge(sk); 1465 1466 /* Cleans up our, hopefully empty, out_of_order_queue. */ 1467 __skb_queue_purge(&tp->out_of_order_queue); 1468 1469 /* Clean prequeue, it must be empty really */ 1470 __skb_queue_purge(&tp->ucopy.prequeue); 1471 1472 /* Clean up a referenced TCP bind bucket. */ 1473 if (inet_csk(sk)->icsk_bind_hash) 1474 inet_put_port(&tcp_hashinfo, sk); 1475 1476 /* 1477 * If sendmsg cached page exists, toss it. 1478 */ 1479 if (sk->sk_sndmsg_page) { 1480 __free_page(sk->sk_sndmsg_page); 1481 sk->sk_sndmsg_page = NULL; 1482 } 1483 1484 atomic_dec(&tcp_sockets_allocated); 1485 1486 return 0; 1487} 1488 1489EXPORT_SYMBOL(tcp_v4_destroy_sock); 1490 1491#ifdef CONFIG_PROC_FS 1492/* Proc filesystem TCP sock list dumping. */ 1493 1494static inline struct inet_timewait_sock *tw_head(struct hlist_head *head) 1495{ 1496 return hlist_empty(head) ? NULL : 1497 list_entry(head->first, struct inet_timewait_sock, tw_node); 1498} 1499 1500static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw) 1501{ 1502 return tw->tw_node.next ? 1503 hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL; 1504} 1505 1506static void *listening_get_next(struct seq_file *seq, void *cur) 1507{ 1508 struct inet_connection_sock *icsk; 1509 struct hlist_node *node; 1510 struct sock *sk = cur; 1511 struct tcp_iter_state* st = seq->private; 1512 1513 if (!sk) { 1514 st->bucket = 0; 1515 sk = sk_head(&tcp_hashinfo.listening_hash[0]); 1516 goto get_sk; 1517 } 1518 1519 ++st->num; 1520 1521 if (st->state == TCP_SEQ_STATE_OPENREQ) { 1522 struct request_sock *req = cur; 1523 1524 icsk = inet_csk(st->syn_wait_sk); 1525 req = req->dl_next; 1526 while (1) { 1527 while (req) { 1528 if (req->rsk_ops->family == st->family) { 1529 cur = req; 1530 goto out; 1531 } 1532 req = req->dl_next; 1533 } 1534 if (++st->sbucket >= TCP_SYNQ_HSIZE) 1535 break; 1536get_req: 1537 req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket]; 1538 } 1539 sk = sk_next(st->syn_wait_sk); 1540 st->state = TCP_SEQ_STATE_LISTENING; 1541 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1542 } else { 1543 icsk = inet_csk(sk); 1544 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1545 if (reqsk_queue_len(&icsk->icsk_accept_queue)) 1546 goto start_req; 1547 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1548 sk = sk_next(sk); 1549 } 1550get_sk: 1551 sk_for_each_from(sk, node) { 1552 if (sk->sk_family == st->family) { 1553 cur = sk; 1554 goto out; 1555 } 1556 icsk = inet_csk(sk); 1557 read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1558 if (reqsk_queue_len(&icsk->icsk_accept_queue)) { 1559start_req: 1560 st->uid = sock_i_uid(sk); 1561 st->syn_wait_sk = sk; 1562 st->state = TCP_SEQ_STATE_OPENREQ; 1563 st->sbucket = 0; 1564 goto get_req; 1565 } 1566 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1567 } 1568 if (++st->bucket < INET_LHTABLE_SIZE) { 1569 sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]); 1570 goto get_sk; 1571 } 1572 cur = NULL; 1573out: 1574 return cur; 1575} 1576 1577static void *listening_get_idx(struct seq_file *seq, loff_t *pos) 1578{ 1579 void *rc = listening_get_next(seq, NULL); 1580 1581 while (rc && *pos) { 1582 rc = listening_get_next(seq, rc); 1583 --*pos; 1584 } 1585 return rc; 1586} 1587 1588static void *established_get_first(struct seq_file *seq) 1589{ 1590 struct tcp_iter_state* st = seq->private; 1591 void *rc = NULL; 1592 1593 for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) { 1594 struct sock *sk; 1595 struct hlist_node *node; 1596 struct inet_timewait_sock *tw; 1597 1598 /* We can reschedule _before_ having picked the target: */ 1599 cond_resched_softirq(); 1600 1601 read_lock(&tcp_hashinfo.ehash[st->bucket].lock); 1602 sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { 1603 if (sk->sk_family != st->family) { 1604 continue; 1605 } 1606 rc = sk; 1607 goto out; 1608 } 1609 st->state = TCP_SEQ_STATE_TIME_WAIT; 1610 inet_twsk_for_each(tw, node, 1611 &tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain) { 1612 if (tw->tw_family != st->family) { 1613 continue; 1614 } 1615 rc = tw; 1616 goto out; 1617 } 1618 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock); 1619 st->state = TCP_SEQ_STATE_ESTABLISHED; 1620 } 1621out: 1622 return rc; 1623} 1624 1625static void *established_get_next(struct seq_file *seq, void *cur) 1626{ 1627 struct sock *sk = cur; 1628 struct inet_timewait_sock *tw; 1629 struct hlist_node *node; 1630 struct tcp_iter_state* st = seq->private; 1631 1632 ++st->num; 1633 1634 if (st->state == TCP_SEQ_STATE_TIME_WAIT) { 1635 tw = cur; 1636 tw = tw_next(tw); 1637get_tw: 1638 while (tw && tw->tw_family != st->family) { 1639 tw = tw_next(tw); 1640 } 1641 if (tw) { 1642 cur = tw; 1643 goto out; 1644 } 1645 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock); 1646 st->state = TCP_SEQ_STATE_ESTABLISHED; 1647 1648 /* We can reschedule between buckets: */ 1649 cond_resched_softirq(); 1650 1651 if (++st->bucket < tcp_hashinfo.ehash_size) { 1652 read_lock(&tcp_hashinfo.ehash[st->bucket].lock); 1653 sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain); 1654 } else { 1655 cur = NULL; 1656 goto out; 1657 } 1658 } else 1659 sk = sk_next(sk); 1660 1661 sk_for_each_from(sk, node) { 1662 if (sk->sk_family == st->family) 1663 goto found; 1664 } 1665 1666 st->state = TCP_SEQ_STATE_TIME_WAIT; 1667 tw = tw_head(&tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain); 1668 goto get_tw; 1669found: 1670 cur = sk; 1671out: 1672 return cur; 1673} 1674 1675static void *established_get_idx(struct seq_file *seq, loff_t pos) 1676{ 1677 void *rc = established_get_first(seq); 1678 1679 while (rc && pos) { 1680 rc = established_get_next(seq, rc); 1681 --pos; 1682 } 1683 return rc; 1684} 1685 1686static void *tcp_get_idx(struct seq_file *seq, loff_t pos) 1687{ 1688 void *rc; 1689 struct tcp_iter_state* st = seq->private; 1690 1691 inet_listen_lock(&tcp_hashinfo); 1692 st->state = TCP_SEQ_STATE_LISTENING; 1693 rc = listening_get_idx(seq, &pos); 1694 1695 if (!rc) { 1696 inet_listen_unlock(&tcp_hashinfo); 1697 local_bh_disable(); 1698 st->state = TCP_SEQ_STATE_ESTABLISHED; 1699 rc = established_get_idx(seq, pos); 1700 } 1701 1702 return rc; 1703} 1704 1705static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) 1706{ 1707 struct tcp_iter_state* st = seq->private; 1708 st->state = TCP_SEQ_STATE_LISTENING; 1709 st->num = 0; 1710 return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 1711} 1712 1713static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1714{ 1715 void *rc = NULL; 1716 struct tcp_iter_state* st; 1717 1718 if (v == SEQ_START_TOKEN) { 1719 rc = tcp_get_idx(seq, 0); 1720 goto out; 1721 } 1722 st = seq->private; 1723 1724 switch (st->state) { 1725 case TCP_SEQ_STATE_OPENREQ: 1726 case TCP_SEQ_STATE_LISTENING: 1727 rc = listening_get_next(seq, v); 1728 if (!rc) { 1729 inet_listen_unlock(&tcp_hashinfo); 1730 local_bh_disable(); 1731 st->state = TCP_SEQ_STATE_ESTABLISHED; 1732 rc = established_get_first(seq); 1733 } 1734 break; 1735 case TCP_SEQ_STATE_ESTABLISHED: 1736 case TCP_SEQ_STATE_TIME_WAIT: 1737 rc = established_get_next(seq, v); 1738 break; 1739 } 1740out: 1741 ++*pos; 1742 return rc; 1743} 1744 1745static void tcp_seq_stop(struct seq_file *seq, void *v) 1746{ 1747 struct tcp_iter_state* st = seq->private; 1748 1749 switch (st->state) { 1750 case TCP_SEQ_STATE_OPENREQ: 1751 if (v) { 1752 struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk); 1753 read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock); 1754 } 1755 case TCP_SEQ_STATE_LISTENING: 1756 if (v != SEQ_START_TOKEN) 1757 inet_listen_unlock(&tcp_hashinfo); 1758 break; 1759 case TCP_SEQ_STATE_TIME_WAIT: 1760 case TCP_SEQ_STATE_ESTABLISHED: 1761 if (v) 1762 read_unlock(&tcp_hashinfo.ehash[st->bucket].lock); 1763 local_bh_enable(); 1764 break; 1765 } 1766} 1767 1768static int tcp_seq_open(struct inode *inode, struct file *file) 1769{ 1770 struct tcp_seq_afinfo *afinfo = PDE(inode)->data; 1771 struct seq_file *seq; 1772 struct tcp_iter_state *s; 1773 int rc; 1774 1775 if (unlikely(afinfo == NULL)) 1776 return -EINVAL; 1777 1778 s = kmalloc(sizeof(*s), GFP_KERNEL); 1779 if (!s) 1780 return -ENOMEM; 1781 memset(s, 0, sizeof(*s)); 1782 s->family = afinfo->family; 1783 s->seq_ops.start = tcp_seq_start; 1784 s->seq_ops.next = tcp_seq_next; 1785 s->seq_ops.show = afinfo->seq_show; 1786 s->seq_ops.stop = tcp_seq_stop; 1787 1788 rc = seq_open(file, &s->seq_ops); 1789 if (rc) 1790 goto out_kfree; 1791 seq = file->private_data; 1792 seq->private = s; 1793out: 1794 return rc; 1795out_kfree: 1796 kfree(s); 1797 goto out; 1798} 1799 1800int tcp_proc_register(struct tcp_seq_afinfo *afinfo) 1801{ 1802 int rc = 0; 1803 struct proc_dir_entry *p; 1804 1805 if (!afinfo) 1806 return -EINVAL; 1807 afinfo->seq_fops->owner = afinfo->owner; 1808 afinfo->seq_fops->open = tcp_seq_open; 1809 afinfo->seq_fops->read = seq_read; 1810 afinfo->seq_fops->llseek = seq_lseek; 1811 afinfo->seq_fops->release = seq_release_private; 1812 1813 p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops); 1814 if (p) 1815 p->data = afinfo; 1816 else 1817 rc = -ENOMEM; 1818 return rc; 1819} 1820 1821void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo) 1822{ 1823 if (!afinfo) 1824 return; 1825 proc_net_remove(afinfo->name); 1826 memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops)); 1827} 1828 1829static void get_openreq4(struct sock *sk, struct request_sock *req, 1830 char *tmpbuf, int i, int uid) 1831{ 1832 const struct inet_request_sock *ireq = inet_rsk(req); 1833 int ttd = req->expires - jiffies; 1834 1835 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X" 1836 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p", 1837 i, 1838 ireq->loc_addr, 1839 ntohs(inet_sk(sk)->sport), 1840 ireq->rmt_addr, 1841 ntohs(ireq->rmt_port), 1842 TCP_SYN_RECV, 1843 0, 0, /* could print option size, but that is af dependent. */ 1844 1, /* timers active (only the expire timer) */ 1845 jiffies_to_clock_t(ttd), 1846 req->retrans, 1847 uid, 1848 0, /* non standard timer */ 1849 0, /* open_requests have no inode */ 1850 atomic_read(&sk->sk_refcnt), 1851 req); 1852} 1853 1854static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i) 1855{ 1856 int timer_active; 1857 unsigned long timer_expires; 1858 struct tcp_sock *tp = tcp_sk(sp); 1859 const struct inet_connection_sock *icsk = inet_csk(sp); 1860 struct inet_sock *inet = inet_sk(sp); 1861 unsigned int dest = inet->daddr; 1862 unsigned int src = inet->rcv_saddr; 1863 __u16 destp = ntohs(inet->dport); 1864 __u16 srcp = ntohs(inet->sport); 1865 1866 if (icsk->icsk_pending == ICSK_TIME_RETRANS) { 1867 timer_active = 1; 1868 timer_expires = icsk->icsk_timeout; 1869 } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { 1870 timer_active = 4; 1871 timer_expires = icsk->icsk_timeout; 1872 } else if (timer_pending(&sp->sk_timer)) { 1873 timer_active = 2; 1874 timer_expires = sp->sk_timer.expires; 1875 } else { 1876 timer_active = 0; 1877 timer_expires = jiffies; 1878 } 1879 1880 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " 1881 "%08X %5d %8d %lu %d %p %u %u %u %u %d", 1882 i, src, srcp, dest, destp, sp->sk_state, 1883 tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq, 1884 timer_active, 1885 jiffies_to_clock_t(timer_expires - jiffies), 1886 icsk->icsk_retransmits, 1887 sock_i_uid(sp), 1888 icsk->icsk_probes_out, 1889 sock_i_ino(sp), 1890 atomic_read(&sp->sk_refcnt), sp, 1891 icsk->icsk_rto, 1892 icsk->icsk_ack.ato, 1893 (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, 1894 tp->snd_cwnd, 1895 tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh); 1896} 1897 1898static void get_timewait4_sock(struct inet_timewait_sock *tw, char *tmpbuf, int i) 1899{ 1900 unsigned int dest, src; 1901 __u16 destp, srcp; 1902 int ttd = tw->tw_ttd - jiffies; 1903 1904 if (ttd < 0) 1905 ttd = 0; 1906 1907 dest = tw->tw_daddr; 1908 src = tw->tw_rcv_saddr; 1909 destp = ntohs(tw->tw_dport); 1910 srcp = ntohs(tw->tw_sport); 1911 1912 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X" 1913 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p", 1914 i, src, srcp, dest, destp, tw->tw_substate, 0, 0, 1915 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0, 1916 atomic_read(&tw->tw_refcnt), tw); 1917} 1918 1919#define TMPSZ 150 1920 1921static int tcp4_seq_show(struct seq_file *seq, void *v) 1922{ 1923 struct tcp_iter_state* st; 1924 char tmpbuf[TMPSZ + 1]; 1925 1926 if (v == SEQ_START_TOKEN) { 1927 seq_printf(seq, "%-*s\n", TMPSZ - 1, 1928 " sl local_address rem_address st tx_queue " 1929 "rx_queue tr tm->when retrnsmt uid timeout " 1930 "inode"); 1931 goto out; 1932 } 1933 st = seq->private; 1934 1935 switch (st->state) { 1936 case TCP_SEQ_STATE_LISTENING: 1937 case TCP_SEQ_STATE_ESTABLISHED: 1938 get_tcp4_sock(v, tmpbuf, st->num); 1939 break; 1940 case TCP_SEQ_STATE_OPENREQ: 1941 get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid); 1942 break; 1943 case TCP_SEQ_STATE_TIME_WAIT: 1944 get_timewait4_sock(v, tmpbuf, st->num); 1945 break; 1946 } 1947 seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf); 1948out: 1949 return 0; 1950} 1951 1952static struct file_operations tcp4_seq_fops; 1953static struct tcp_seq_afinfo tcp4_seq_afinfo = { 1954 .owner = THIS_MODULE, 1955 .name = "tcp", 1956 .family = AF_INET, 1957 .seq_show = tcp4_seq_show, 1958 .seq_fops = &tcp4_seq_fops, 1959}; 1960 1961int __init tcp4_proc_init(void) 1962{ 1963 return tcp_proc_register(&tcp4_seq_afinfo); 1964} 1965 1966void tcp4_proc_exit(void) 1967{ 1968 tcp_proc_unregister(&tcp4_seq_afinfo); 1969} 1970#endif /* CONFIG_PROC_FS */ 1971 1972struct proto tcp_prot = { 1973 .name = "TCP", 1974 .owner = THIS_MODULE, 1975 .close = tcp_close, 1976 .connect = tcp_v4_connect, 1977 .disconnect = tcp_disconnect, 1978 .accept = inet_csk_accept, 1979 .ioctl = tcp_ioctl, 1980 .init = tcp_v4_init_sock, 1981 .destroy = tcp_v4_destroy_sock, 1982 .shutdown = tcp_shutdown, 1983 .setsockopt = tcp_setsockopt, 1984 .getsockopt = tcp_getsockopt, 1985 .sendmsg = tcp_sendmsg, 1986 .recvmsg = tcp_recvmsg, 1987 .backlog_rcv = tcp_v4_do_rcv, 1988 .hash = tcp_v4_hash, 1989 .unhash = tcp_unhash, 1990 .get_port = tcp_v4_get_port, 1991 .enter_memory_pressure = tcp_enter_memory_pressure, 1992 .sockets_allocated = &tcp_sockets_allocated, 1993 .orphan_count = &tcp_orphan_count, 1994 .memory_allocated = &tcp_memory_allocated, 1995 .memory_pressure = &tcp_memory_pressure, 1996 .sysctl_mem = sysctl_tcp_mem, 1997 .sysctl_wmem = sysctl_tcp_wmem, 1998 .sysctl_rmem = sysctl_tcp_rmem, 1999 .max_header = MAX_TCP_HEADER, 2000 .obj_size = sizeof(struct tcp_sock), 2001 .twsk_obj_size = sizeof(struct tcp_timewait_sock), 2002 .rsk_prot = &tcp_request_sock_ops, 2003}; 2004 2005 2006 2007void __init tcp_v4_init(struct net_proto_family *ops) 2008{ 2009 int err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_TCP, &tcp_socket); 2010 if (err < 0) 2011 panic("Failed to create the TCP control socket.\n"); 2012 tcp_socket->sk->sk_allocation = GFP_ATOMIC; 2013 inet_sk(tcp_socket->sk)->uc_ttl = -1; 2014 2015 /* Unhash it so that IP input processing does not even 2016 * see it, we do not wish this socket to see incoming 2017 * packets. 2018 */ 2019 tcp_socket->sk->sk_prot->unhash(tcp_socket->sk); 2020} 2021 2022EXPORT_SYMBOL(ipv4_specific); 2023EXPORT_SYMBOL(inet_bind_bucket_create); 2024EXPORT_SYMBOL(tcp_hashinfo); 2025EXPORT_SYMBOL(tcp_prot); 2026EXPORT_SYMBOL(tcp_unhash); 2027EXPORT_SYMBOL(tcp_v4_conn_request); 2028EXPORT_SYMBOL(tcp_v4_connect); 2029EXPORT_SYMBOL(tcp_v4_do_rcv); 2030EXPORT_SYMBOL(tcp_v4_remember_stamp); 2031EXPORT_SYMBOL(tcp_v4_send_check); 2032EXPORT_SYMBOL(tcp_v4_syn_recv_sock); 2033 2034#ifdef CONFIG_PROC_FS 2035EXPORT_SYMBOL(tcp_proc_register); 2036EXPORT_SYMBOL(tcp_proc_unregister); 2037#endif 2038EXPORT_SYMBOL(sysctl_local_port_range); 2039EXPORT_SYMBOL(sysctl_tcp_low_latency); 2040EXPORT_SYMBOL(sysctl_tcp_tw_reuse); 2041 2042