tcp_ipv4.c 62.1 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Implementation of the Transmission Control Protocol(TCP).
 *
 * Version:	$Id: tcp_ipv4.c,v 1.240 2002/02/01 22:01:04 davem Exp $
 *
 *		IPv4 specific functions
 *
 *
 *		code split from:
 *		linux/ipv4/tcp.c
 *		linux/ipv4/tcp_input.c
 *		linux/ipv4/tcp_output.c
 *
 *		See tcp.c for author information
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

/*
 * Changes:
 *		David S. Miller	:	New socket lookup architecture.
 *					This code is dedicated to John Dyson.
 *		David S. Miller :	Change semantics of established hash,
 *					half is devoted to TIME_WAIT sockets
 *					and the rest go in the other half.
 *		Andi Kleen :		Add support for syncookies and fixed
 *					some bugs: ip options weren't passed to
 *					the TCP layer, missed a check for an
 *					ACK bit.
 *		Andi Kleen :		Implemented fast path mtu discovery.
 *	     				Fixed many serious bugs in the
39
 *					request_sock handling and moved
L
Linus Torvalds 已提交
40 41
 *					most of it into the af independent code.
 *					Added tail drop and some other bugfixes.
S
Stephen Hemminger 已提交
42
 *					Added new listen semantics.
L
Linus Torvalds 已提交
43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
 *		Mike McLagan	:	Routing by source
 *	Juan Jose Ciarlante:		ip_dynaddr bits
 *		Andi Kleen:		various fixes.
 *	Vitaly E. Lavrov	:	Transparent proxy revived after year
 *					coma.
 *	Andi Kleen		:	Fix new listen.
 *	Andi Kleen		:	Fix accept error reporting.
 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
 *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
 *					a single port at the same time.
 */


#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/cache.h>
#include <linux/jhash.h>
#include <linux/init.h>
#include <linux/times.h>

#include <net/icmp.h>
66
#include <net/inet_hashtables.h>
L
Linus Torvalds 已提交
67
#include <net/tcp.h>
68
#include <net/transp_v6.h>
L
Linus Torvalds 已提交
69 70
#include <net/ipv6.h>
#include <net/inet_common.h>
71
#include <net/timewait_sock.h>
L
Linus Torvalds 已提交
72
#include <net/xfrm.h>
C
Chris Leech 已提交
73
#include <net/netdma.h>
L
Linus Torvalds 已提交
74 75 76 77 78 79 80

#include <linux/inet.h>
#include <linux/ipv6.h>
#include <linux/stddef.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

81 82 83
#include <linux/crypto.h>
#include <linux/scatterlist.h>

84 85
int sysctl_tcp_tw_reuse __read_mostly;
int sysctl_tcp_low_latency __read_mostly;
L
Linus Torvalds 已提交
86 87 88 89 90 91 92

/* Check TCP sequence numbers in ICMP packets. */
#define ICMP_MIN_LENGTH 8

/* Socket used for sending RSTs */
static struct socket *tcp_socket;

93
void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
L
Linus Torvalds 已提交
94

95 96 97 98 99 100 101
#ifdef CONFIG_TCP_MD5SIG
static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr);
static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
				   __be32 saddr, __be32 daddr, struct tcphdr *th,
				   int protocol, int tcplen);
#endif

102
struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
103
	.lhash_lock	= __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
104 105
	.lhash_users	= ATOMIC_INIT(0),
	.lhash_wait	= __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
L
Linus Torvalds 已提交
106 107
};

108 109
static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
{
110 111
	return inet_csk_get_port(&tcp_hashinfo, sk, snum,
				 inet_csk_bind_conflict);
112 113
}

L
Linus Torvalds 已提交
114 115
static void tcp_v4_hash(struct sock *sk)
{
116
	inet_hash(&tcp_hashinfo, sk);
L
Linus Torvalds 已提交
117 118 119 120
}

void tcp_unhash(struct sock *sk)
{
121
	inet_unhash(&tcp_hashinfo, sk);
L
Linus Torvalds 已提交
122 123
}

124
static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
L
Linus Torvalds 已提交
125 126 127 128 129 130 131
{
	return secure_tcp_sequence_number(skb->nh.iph->daddr,
					  skb->nh.iph->saddr,
					  skb->h.th->dest,
					  skb->h.th->source);
}

132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164
int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
{
	const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
	struct tcp_sock *tp = tcp_sk(sk);

	/* With PAWS, it is safe from the viewpoint
	   of data integrity. Even without PAWS it is safe provided sequence
	   spaces do not overlap i.e. at data rates <= 80Mbit/sec.

	   Actually, the idea is close to VJ's one, only timestamp cache is
	   held not per host, but per port pair and TW bucket is used as state
	   holder.

	   If TW bucket has been already destroyed we fall back to VJ's scheme
	   and use initial timestamp retrieved from peer table.
	 */
	if (tcptw->tw_ts_recent_stamp &&
	    (twp == NULL || (sysctl_tcp_tw_reuse &&
			     xtime.tv_sec - tcptw->tw_ts_recent_stamp > 1))) {
		tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
		if (tp->write_seq == 0)
			tp->write_seq = 1;
		tp->rx_opt.ts_recent	   = tcptw->tw_ts_recent;
		tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
		sock_hold(sktw);
		return 1;
	}

	return 0;
}

EXPORT_SYMBOL_GPL(tcp_twsk_unique);

L
Linus Torvalds 已提交
165 166 167 168 169 170 171
/* This will initiate an outgoing connection. */
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct tcp_sock *tp = tcp_sk(sk);
	struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
	struct rtable *rt;
172
	__be32 daddr, nexthop;
L
Linus Torvalds 已提交
173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214
	int tmp;
	int err;

	if (addr_len < sizeof(struct sockaddr_in))
		return -EINVAL;

	if (usin->sin_family != AF_INET)
		return -EAFNOSUPPORT;

	nexthop = daddr = usin->sin_addr.s_addr;
	if (inet->opt && inet->opt->srr) {
		if (!daddr)
			return -EINVAL;
		nexthop = inet->opt->faddr;
	}

	tmp = ip_route_connect(&rt, nexthop, inet->saddr,
			       RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
			       IPPROTO_TCP,
			       inet->sport, usin->sin_port, sk);
	if (tmp < 0)
		return tmp;

	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
		ip_rt_put(rt);
		return -ENETUNREACH;
	}

	if (!inet->opt || !inet->opt->srr)
		daddr = rt->rt_dst;

	if (!inet->saddr)
		inet->saddr = rt->rt_src;
	inet->rcv_saddr = inet->saddr;

	if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
		/* Reset inherited state */
		tp->rx_opt.ts_recent	   = 0;
		tp->rx_opt.ts_recent_stamp = 0;
		tp->write_seq		   = 0;
	}

215
	if (tcp_death_row.sysctl_tw_recycle &&
L
Linus Torvalds 已提交
216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232
	    !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
		struct inet_peer *peer = rt_get_peer(rt);

		/* VJ's idea. We save last timestamp seen from
		 * the destination in peer table, when entering state TIME-WAIT
		 * and initialize rx_opt.ts_recent from it, when trying new connection.
		 */

		if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) {
			tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
			tp->rx_opt.ts_recent = peer->tcp_ts;
		}
	}

	inet->dport = usin->sin_port;
	inet->daddr = daddr;

233
	inet_csk(sk)->icsk_ext_hdr_len = 0;
L
Linus Torvalds 已提交
234
	if (inet->opt)
235
		inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
L
Linus Torvalds 已提交
236 237 238 239 240 241 242 243 244

	tp->rx_opt.mss_clamp = 536;

	/* Socket identity is still unknown (sport may be zero).
	 * However we set state to SYN-SENT and not releasing socket
	 * lock select source port, enter ourselves into the hash tables and
	 * complete initialization after this.
	 */
	tcp_set_state(sk, TCP_SYN_SENT);
245
	err = inet_hash_connect(&tcp_death_row, sk);
L
Linus Torvalds 已提交
246 247 248
	if (err)
		goto failure;

249
	err = ip_route_newports(&rt, IPPROTO_TCP, inet->sport, inet->dport, sk);
L
Linus Torvalds 已提交
250 251 252 253
	if (err)
		goto failure;

	/* OK, now commit destination to socket.  */
254
	sk->sk_gso_type = SKB_GSO_TCPV4;
255
	sk_setup_caps(sk, &rt->u.dst);
L
Linus Torvalds 已提交
256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283

	if (!tp->write_seq)
		tp->write_seq = secure_tcp_sequence_number(inet->saddr,
							   inet->daddr,
							   inet->sport,
							   usin->sin_port);

	inet->id = tp->write_seq ^ jiffies;

	err = tcp_connect(sk);
	rt = NULL;
	if (err)
		goto failure;

	return 0;

failure:
	/* This unhashes the socket and releases the local port, if necessary. */
	tcp_set_state(sk, TCP_CLOSE);
	ip_rt_put(rt);
	sk->sk_route_caps = 0;
	inet->dport = 0;
	return err;
}

/*
 * This routine does path mtu discovery as defined in RFC1191.
 */
S
Stephen Hemminger 已提交
284
static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
L
Linus Torvalds 已提交
285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315
{
	struct dst_entry *dst;
	struct inet_sock *inet = inet_sk(sk);

	/* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
	 * send out by Linux are always <576bytes so they should go through
	 * unfragmented).
	 */
	if (sk->sk_state == TCP_LISTEN)
		return;

	/* We don't check in the destentry if pmtu discovery is forbidden
	 * on this route. We just assume that no packet_to_big packets
	 * are send back when pmtu discovery is not active.
     	 * There is a small race when the user changes this flag in the
	 * route, but I think that's acceptable.
	 */
	if ((dst = __sk_dst_check(sk, 0)) == NULL)
		return;

	dst->ops->update_pmtu(dst, mtu);

	/* Something is about to be wrong... Remember soft error
	 * for the case, if this connection will not able to recover.
	 */
	if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
		sk->sk_err_soft = EMSGSIZE;

	mtu = dst_mtu(dst);

	if (inet->pmtudisc != IP_PMTUDISC_DONT &&
316
	    inet_csk(sk)->icsk_pmtu_cookie > mtu) {
L
Linus Torvalds 已提交
317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360
		tcp_sync_mss(sk, mtu);

		/* Resend the TCP packet because it's
		 * clear that the old packet has been
		 * dropped. This is the new "fast" path mtu
		 * discovery.
		 */
		tcp_simple_retransmit(sk);
	} /* else let the usual retransmit timer handle it */
}

/*
 * This routine is called by the ICMP module when it gets some
 * sort of error condition.  If err < 0 then the socket should
 * be closed and the error returned to the user.  If err > 0
 * it's just the icmp type << 8 | icmp code.  After adjustment
 * header points to the first 8 bytes of the tcp header.  We need
 * to find the appropriate port.
 *
 * The locking strategy used here is very "optimistic". When
 * someone else accesses the socket the ICMP is just dropped
 * and for some paths there is no check at all.
 * A more general error queue to queue errors for later handling
 * is probably better.
 *
 */

void tcp_v4_err(struct sk_buff *skb, u32 info)
{
	struct iphdr *iph = (struct iphdr *)skb->data;
	struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
	struct tcp_sock *tp;
	struct inet_sock *inet;
	int type = skb->h.icmph->type;
	int code = skb->h.icmph->code;
	struct sock *sk;
	__u32 seq;
	int err;

	if (skb->len < (iph->ihl << 2) + 8) {
		ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
		return;
	}

361
	sk = inet_lookup(&tcp_hashinfo, iph->daddr, th->dest, iph->saddr,
362
			 th->source, inet_iif(skb));
L
Linus Torvalds 已提交
363 364 365 366 367
	if (!sk) {
		ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
		return;
	}
	if (sk->sk_state == TCP_TIME_WAIT) {
368
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385
		return;
	}

	bh_lock_sock(sk);
	/* If too many ICMPs get dropped on busy
	 * servers this needs to be solved differently.
	 */
	if (sock_owned_by_user(sk))
		NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);

	if (sk->sk_state == TCP_CLOSE)
		goto out;

	tp = tcp_sk(sk);
	seq = ntohl(th->seq);
	if (sk->sk_state != TCP_LISTEN &&
	    !between(seq, tp->snd_una, tp->snd_nxt)) {
386
		NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
L
Linus Torvalds 已提交
387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416
		goto out;
	}

	switch (type) {
	case ICMP_SOURCE_QUENCH:
		/* Just silently ignore these. */
		goto out;
	case ICMP_PARAMETERPROB:
		err = EPROTO;
		break;
	case ICMP_DEST_UNREACH:
		if (code > NR_ICMP_UNREACH)
			goto out;

		if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
			if (!sock_owned_by_user(sk))
				do_pmtu_discovery(sk, iph, info);
			goto out;
		}

		err = icmp_err_convert[code].errno;
		break;
	case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;
		break;
	default:
		goto out;
	}

	switch (sk->sk_state) {
417
		struct request_sock *req, **prev;
L
Linus Torvalds 已提交
418 419 420 421
	case TCP_LISTEN:
		if (sock_owned_by_user(sk))
			goto out;

422 423
		req = inet_csk_search_req(sk, &prev, th->dest,
					  iph->daddr, iph->saddr);
L
Linus Torvalds 已提交
424 425 426 427 428 429 430 431
		if (!req)
			goto out;

		/* ICMPs are not backlogged, hence we cannot get
		   an established socket here.
		 */
		BUG_TRAP(!req->sk);

432
		if (seq != tcp_rsk(req)->snt_isn) {
L
Linus Torvalds 已提交
433 434 435 436 437 438 439 440 441 442
			NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
			goto out;
		}

		/*
		 * Still in SYN_RECV, just remove it silently.
		 * There is no good way to pass the error to the newly
		 * created socket, and POSIX does not want network
		 * errors returned from accept().
		 */
443
		inet_csk_reqsk_queue_drop(sk, req, prev);
L
Linus Torvalds 已提交
444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491
		goto out;

	case TCP_SYN_SENT:
	case TCP_SYN_RECV:  /* Cannot happen.
			       It can f.e. if SYNs crossed.
			     */
		if (!sock_owned_by_user(sk)) {
			sk->sk_err = err;

			sk->sk_error_report(sk);

			tcp_done(sk);
		} else {
			sk->sk_err_soft = err;
		}
		goto out;
	}

	/* If we've already connected we will keep trying
	 * until we time out, or the user gives up.
	 *
	 * rfc1122 4.2.3.9 allows to consider as hard errors
	 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
	 * but it is obsoleted by pmtu discovery).
	 *
	 * Note, that in modern internet, where routing is unreliable
	 * and in each dark corner broken firewalls sit, sending random
	 * errors ordered by their masters even this two messages finally lose
	 * their original sense (even Linux sends invalid PORT_UNREACHs)
	 *
	 * Now we are in compliance with RFCs.
	 *							--ANK (980905)
	 */

	inet = inet_sk(sk);
	if (!sock_owned_by_user(sk) && inet->recverr) {
		sk->sk_err = err;
		sk->sk_error_report(sk);
	} else	{ /* Only an error on timeout */
		sk->sk_err_soft = err;
	}

out:
	bh_unlock_sock(sk);
	sock_put(sk);
}

/* This routine computes an IPv4 TCP checksum. */
492
void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
L
Linus Torvalds 已提交
493 494
{
	struct inet_sock *inet = inet_sk(sk);
495
	struct tcphdr *th = skb->h.th;
L
Linus Torvalds 已提交
496

497
	if (skb->ip_summed == CHECKSUM_PARTIAL) {
L
Linus Torvalds 已提交
498 499 500 501 502 503 504 505 506 507
		th->check = ~tcp_v4_check(th, len, inet->saddr, inet->daddr, 0);
		skb->csum = offsetof(struct tcphdr, check);
	} else {
		th->check = tcp_v4_check(th, len, inet->saddr, inet->daddr,
					 csum_partial((char *)th,
						      th->doff << 2,
						      skb->csum));
	}
}

508 509 510 511 512 513 514 515 516 517 518 519 520 521
int tcp_v4_gso_send_check(struct sk_buff *skb)
{
	struct iphdr *iph;
	struct tcphdr *th;

	if (!pskb_may_pull(skb, sizeof(*th)))
		return -EINVAL;

	iph = skb->nh.iph;
	th = skb->h.th;

	th->check = 0;
	th->check = ~tcp_v4_check(th, skb->len, iph->saddr, iph->daddr, 0);
	skb->csum = offsetof(struct tcphdr, check);
522
	skb->ip_summed = CHECKSUM_PARTIAL;
523 524 525
	return 0;
}

L
Linus Torvalds 已提交
526 527 528 529 530 531 532 533 534 535 536 537 538
/*
 *	This routine will send an RST to the other tcp.
 *
 *	Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
 *		      for reset.
 *	Answer: if a packet caused RST, it is not for a socket
 *		existing in our system, if it is matched to a socket,
 *		it is just duplicate segment or bug in other side's TCP.
 *		So that we build reply only basing on parameters
 *		arrived with segment.
 *	Exception: precedence violation. We do not implement it in any case.
 */

539
static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
540 541
{
	struct tcphdr *th = skb->h.th;
542 543 544
	struct {
		struct tcphdr th;
#ifdef CONFIG_TCP_MD5SIG
545
		__be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
546 547
#endif
	} rep;
L
Linus Torvalds 已提交
548
	struct ip_reply_arg arg;
549 550 551
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
L
Linus Torvalds 已提交
552 553 554 555 556 557 558 559 560

	/* Never send a reset in response to a reset. */
	if (th->rst)
		return;

	if (((struct rtable *)skb->dst)->rt_type != RTN_LOCAL)
		return;

	/* Swap the send and the receive. */
561 562 563 564 565
	memset(&rep, 0, sizeof(rep));
	rep.th.dest   = th->source;
	rep.th.source = th->dest;
	rep.th.doff   = sizeof(struct tcphdr) / 4;
	rep.th.rst    = 1;
L
Linus Torvalds 已提交
566 567

	if (th->ack) {
568
		rep.th.seq = th->ack_seq;
L
Linus Torvalds 已提交
569
	} else {
570 571 572
		rep.th.ack = 1;
		rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
				       skb->len - (th->doff << 2));
L
Linus Torvalds 已提交
573 574 575
	}

	memset(&arg, 0, sizeof arg);
576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598
	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);

#ifdef CONFIG_TCP_MD5SIG
	key = sk ? tcp_v4_md5_do_lookup(sk, skb->nh.iph->daddr) : NULL;
	if (key) {
		rep.opt[0] = htonl((TCPOPT_NOP << 24) |
				   (TCPOPT_NOP << 16) |
				   (TCPOPT_MD5SIG << 8) |
				   TCPOLEN_MD5SIG);
		/* Update length and the length the header thinks exists */
		arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
		rep.th.doff = arg.iov[0].iov_len / 4;

		tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[1],
					key,
					skb->nh.iph->daddr,
					skb->nh.iph->saddr,
					&rep.th, IPPROTO_TCP,
					arg.iov[0].iov_len);
	}
#endif

L
Linus Torvalds 已提交
599 600 601 602 603
	arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
				      skb->nh.iph->saddr, /*XXX*/
				      sizeof(struct tcphdr), IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;

604
	ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
605 606 607 608 609 610 611 612 613

	TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
	TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
}

/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
   outside socket context is ugly, certainly. What can I do?
 */

614 615
static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
			    struct sk_buff *skb, u32 seq, u32 ack,
L
Linus Torvalds 已提交
616 617 618 619 620
			    u32 win, u32 ts)
{
	struct tcphdr *th = skb->h.th;
	struct {
		struct tcphdr th;
621
		__be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
622
#ifdef CONFIG_TCP_MD5SIG
623
			   + (TCPOLEN_MD5SIG_ALIGNED >> 2)
624 625
#endif
			];
L
Linus Torvalds 已提交
626 627
	} rep;
	struct ip_reply_arg arg;
628 629 630 631
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
	struct tcp_md5sig_key tw_key;
#endif
L
Linus Torvalds 已提交
632 633 634 635 636 637 638

	memset(&rep.th, 0, sizeof(struct tcphdr));
	memset(&arg, 0, sizeof arg);

	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);
	if (ts) {
639 640 641 642 643 644
		rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
				   (TCPOPT_TIMESTAMP << 8) |
				   TCPOLEN_TIMESTAMP);
		rep.opt[1] = htonl(tcp_time_stamp);
		rep.opt[2] = htonl(ts);
		arg.iov[0].iov_len = TCPOLEN_TSTAMP_ALIGNED;
L
Linus Torvalds 已提交
645 646 647 648 649 650 651 652 653 654 655
	}

	/* Swap the send and the receive. */
	rep.th.dest    = th->source;
	rep.th.source  = th->dest;
	rep.th.doff    = arg.iov[0].iov_len / 4;
	rep.th.seq     = htonl(seq);
	rep.th.ack_seq = htonl(ack);
	rep.th.ack     = 1;
	rep.th.window  = htons(win);

656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693
#ifdef CONFIG_TCP_MD5SIG
	/*
	 * The SKB holds an imcoming packet, but may not have a valid ->sk
	 * pointer. This is especially the case when we're dealing with a
	 * TIME_WAIT ack, because the sk structure is long gone, and only
	 * the tcp_timewait_sock remains. So the md5 key is stashed in that
	 * structure, and we use it in preference.  I believe that (twsk ||
	 * skb->sk) holds true, but we program defensively.
	 */
	if (!twsk && skb->sk) {
		key = tcp_v4_md5_do_lookup(skb->sk, skb->nh.iph->daddr);
	} else if (twsk && twsk->tw_md5_keylen) {
		tw_key.key = twsk->tw_md5_key;
		tw_key.keylen = twsk->tw_md5_keylen;
		key = &tw_key;
	} else {
		key = NULL;
	}

	if (key) {
		int offset = (ts) ? 3 : 0;

		rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
					  (TCPOPT_NOP << 16) |
					  (TCPOPT_MD5SIG << 8) |
					  TCPOLEN_MD5SIG);
		arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
		rep.th.doff = arg.iov[0].iov_len/4;

		tcp_v4_do_calc_md5_hash((__u8 *)&rep.opt[offset],
					key,
					skb->nh.iph->daddr,
					skb->nh.iph->saddr,
					&rep.th, IPPROTO_TCP,
					arg.iov[0].iov_len);
	}
#endif

L
Linus Torvalds 已提交
694 695 696 697 698 699 700 701 702 703 704 705
	arg.csum = csum_tcpudp_nofold(skb->nh.iph->daddr,
				      skb->nh.iph->saddr, /*XXX*/
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;

	ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);

	TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
}

static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
706
	struct inet_timewait_sock *tw = inet_twsk(sk);
707
	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
708

709
	tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
710
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcptw->tw_ts_recent);
L
Linus Torvalds 已提交
711

712
	inet_twsk_put(tw);
L
Linus Torvalds 已提交
713 714
}

715
static void tcp_v4_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req)
L
Linus Torvalds 已提交
716
{
717 718
	tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
			tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
L
Linus Torvalds 已提交
719 720 721 722 723
			req->ts_recent);
}

/*
 *	Send a SYN-ACK after having received an ACK.
724
 *	This still operates on a request_sock only, not on a big
L
Linus Torvalds 已提交
725 726
 *	socket.
 */
727
static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
L
Linus Torvalds 已提交
728 729
			      struct dst_entry *dst)
{
730
	const struct inet_request_sock *ireq = inet_rsk(req);
L
Linus Torvalds 已提交
731 732 733 734
	int err = -1;
	struct sk_buff * skb;

	/* First, grab a route. */
735
	if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
L
Linus Torvalds 已提交
736 737 738 739 740 741 742 743
		goto out;

	skb = tcp_make_synack(sk, dst, req);

	if (skb) {
		struct tcphdr *th = skb->h.th;

		th->check = tcp_v4_check(th, skb->len,
744 745
					 ireq->loc_addr,
					 ireq->rmt_addr,
L
Linus Torvalds 已提交
746 747 748
					 csum_partial((char *)th, skb->len,
						      skb->csum));

749 750 751
		err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
					    ireq->rmt_addr,
					    ireq->opt);
752
		err = net_xmit_eval(err);
L
Linus Torvalds 已提交
753 754 755 756 757 758 759 760
	}

out:
	dst_release(dst);
	return err;
}

/*
761
 *	IPv4 request_sock destructor.
L
Linus Torvalds 已提交
762
 */
763
static void tcp_v4_reqsk_destructor(struct request_sock *req)
L
Linus Torvalds 已提交
764
{
J
Jesper Juhl 已提交
765
	kfree(inet_rsk(req)->opt);
L
Linus Torvalds 已提交
766 767
}

768
#ifdef CONFIG_SYN_COOKIES
S
Stephen Hemminger 已提交
769
static void syn_flood_warning(struct sk_buff *skb)
L
Linus Torvalds 已提交
770 771 772 773 774 775 776 777 778 779
{
	static unsigned long warntime;

	if (time_after(jiffies, (warntime + HZ * 60))) {
		warntime = jiffies;
		printk(KERN_INFO
		       "possible SYN flooding on port %d. Sending cookies.\n",
		       ntohs(skb->h.th->dest));
	}
}
780
#endif
L
Linus Torvalds 已提交
781 782

/*
783
 * Save and compile IPv4 options into the request_sock if needed.
L
Linus Torvalds 已提交
784
 */
S
Stephen Hemminger 已提交
785 786
static struct ip_options *tcp_v4_save_options(struct sock *sk,
					      struct sk_buff *skb)
L
Linus Torvalds 已提交
787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803
{
	struct ip_options *opt = &(IPCB(skb)->opt);
	struct ip_options *dopt = NULL;

	if (opt && opt->optlen) {
		int opt_size = optlength(opt);
		dopt = kmalloc(opt_size, GFP_ATOMIC);
		if (dopt) {
			if (ip_options_echo(dopt, skb)) {
				kfree(dopt);
				dopt = NULL;
			}
		}
	}
	return dopt;
}

804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258
#ifdef CONFIG_TCP_MD5SIG
/*
 * RFC2385 MD5 checksumming requires a mapping of
 * IP address->MD5 Key.
 * We need to maintain these in the sk structure.
 */

/* Find the Key structure for an address.  */
static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int i;

	if (!tp->md5sig_info || !tp->md5sig_info->entries4)
		return NULL;
	for (i = 0; i < tp->md5sig_info->entries4; i++) {
		if (tp->md5sig_info->keys4[i].addr == addr)
			return (struct tcp_md5sig_key *)&tp->md5sig_info->keys4[i];
	}
	return NULL;
}

struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
					 struct sock *addr_sk)
{
	return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->daddr);
}

EXPORT_SYMBOL(tcp_v4_md5_lookup);

struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
					       struct request_sock *req)
{
	return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
}

/* This can be called on a newly created socket, from other files */
int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
		      u8 *newkey, u8 newkeylen)
{
	/* Add Key to the list */
	struct tcp4_md5sig_key *key;
	struct tcp_sock *tp = tcp_sk(sk);
	struct tcp4_md5sig_key *keys;

	key = (struct tcp4_md5sig_key *) tcp_v4_md5_do_lookup(sk, addr);
	if (key) {
		/* Pre-existing entry - just update that one. */
		kfree (key->key);
		key->key = newkey;
		key->keylen = newkeylen;
	} else {
		if (!tp->md5sig_info) {
			tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info), GFP_ATOMIC);
			if (!tp->md5sig_info) {
				kfree(newkey);
				return -ENOMEM;
			}
		}
		if (tcp_alloc_md5sig_pool() == NULL) {
			kfree(newkey);
			return -ENOMEM;
		}
		if (tp->md5sig_info->alloced4 == tp->md5sig_info->entries4) {
			keys = kmalloc((sizeof(struct tcp4_md5sig_key) *
				       (tp->md5sig_info->entries4 + 1)), GFP_ATOMIC);
			if (!keys) {
				kfree(newkey);
				tcp_free_md5sig_pool();
				return -ENOMEM;
			}

			if (tp->md5sig_info->entries4)
				memcpy(keys, tp->md5sig_info->keys4,
				       (sizeof (struct tcp4_md5sig_key) *
					tp->md5sig_info->entries4));

			/* Free old key list, and reference new one */
			if (tp->md5sig_info->keys4)
				kfree(tp->md5sig_info->keys4);
			tp->md5sig_info->keys4 = keys;
			tp->md5sig_info->alloced4++;
		}
		tp->md5sig_info->entries4++;
		tp->md5sig_info->keys4[tp->md5sig_info->entries4 - 1].addr = addr;
		tp->md5sig_info->keys4[tp->md5sig_info->entries4 - 1].key = newkey;
		tp->md5sig_info->keys4[tp->md5sig_info->entries4 - 1].keylen = newkeylen;
	}
	return 0;
}

EXPORT_SYMBOL(tcp_v4_md5_do_add);

static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
			       u8 *newkey, u8 newkeylen)
{
	return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->daddr,
				 newkey, newkeylen);
}

int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int i;

	for (i = 0; i < tp->md5sig_info->entries4; i++) {
		if (tp->md5sig_info->keys4[i].addr == addr) {
			/* Free the key */
			kfree(tp->md5sig_info->keys4[i].key);
			tp->md5sig_info->entries4--;

			if (tp->md5sig_info->entries4 == 0) {
				kfree(tp->md5sig_info->keys4);
				tp->md5sig_info->keys4 = NULL;
			} else {
				/* Need to do some manipulation */
				if (tp->md5sig_info->entries4 != i)
					memcpy(&tp->md5sig_info->keys4[i],
					       &tp->md5sig_info->keys4[i+1],
					       (tp->md5sig_info->entries4 - i)
					        * sizeof (struct tcp4_md5sig_key));
			}
			tcp_free_md5sig_pool();
			return 0;
		}
	}
	return -ENOENT;
}

EXPORT_SYMBOL(tcp_v4_md5_do_del);

static void tcp_v4_clear_md5_list (struct sock *sk)
{
	struct tcp_sock *tp = tcp_sk(sk);

	/* Free each key, then the set of key keys,
	 * the crypto element, and then decrement our
	 * hold on the last resort crypto.
	 */
	if (tp->md5sig_info->entries4) {
		int i;
		for (i = 0; i < tp->md5sig_info->entries4; i++)
			kfree(tp->md5sig_info->keys4[i].key);
		tp->md5sig_info->entries4 = 0;
		tcp_free_md5sig_pool();
	}
	if (tp->md5sig_info->keys4) {
		kfree(tp->md5sig_info->keys4);
		tp->md5sig_info->keys4 = NULL;
		tp->md5sig_info->alloced4  = 0;
	}
}

static int tcp_v4_parse_md5_keys (struct sock *sk, char __user *optval,
				  int optlen)
{
	struct tcp_md5sig cmd;
	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
	u8 *newkey;

	if (optlen < sizeof(cmd))
		return -EINVAL;

	if (copy_from_user (&cmd, optval, sizeof(cmd)))
		return -EFAULT;

	if (sin->sin_family != AF_INET)
		return -EINVAL;

	if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
		if (!tcp_sk(sk)->md5sig_info)
			return -ENOENT;
		return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
	}

	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
		return -EINVAL;

	if (!tcp_sk(sk)->md5sig_info) {
		struct tcp_sock *tp = tcp_sk(sk);
		struct tcp_md5sig_info *p;

		p = kzalloc(sizeof(struct tcp_md5sig_info), GFP_KERNEL);
		if (!p)
			return -EINVAL;

		tp->md5sig_info = p;

	}

	newkey = kmalloc(cmd.tcpm_keylen, GFP_KERNEL);
	if (!newkey)
		return -ENOMEM;
	memcpy(newkey, cmd.tcpm_key, cmd.tcpm_keylen);
	return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
				 newkey, cmd.tcpm_keylen);
}

static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
				   __be32 saddr, __be32 daddr,
				   struct tcphdr *th, int protocol,
				   int tcplen)
{
	struct scatterlist sg[4];
	__u16 data_len;
	int block = 0;
#ifdef CONFIG_TCP_MD5SIG_DEBUG
	int i;
#endif
	__u16 old_checksum;
	struct tcp_md5sig_pool *hp;
	struct tcp4_pseudohdr *bp;
	struct hash_desc *desc;
	int err;
	unsigned int nbytes = 0;

	/*
	 * Okay, so RFC2385 is turned on for this connection,
	 * so we need to generate the MD5 hash for the packet now.
	 */

	hp = tcp_get_md5sig_pool();
	if (!hp)
		goto clear_hash_noput;

	bp = &hp->md5_blk.ip4;
	desc = &hp->md5_desc;

	/*
	 * 1. the TCP pseudo-header (in the order: source IP address,
	 * destination IP address, zero-padded protocol number, and
	 * segment length)
	 */
	bp->saddr = saddr;
	bp->daddr = daddr;
	bp->pad = 0;
	bp->protocol = protocol;
	bp->len = htons(tcplen);
	sg_set_buf(&sg[block++], bp, sizeof(*bp));
	nbytes += sizeof(*bp);

#ifdef CONFIG_TCP_MD5SIG_DEBUG
	printk("Calcuating hash for: ");
	for (i = 0; i < sizeof (*bp); i++)
		printk ("%02x ", (unsigned int)((unsigned char *)bp)[i]);
	printk(" ");
#endif

	/* 2. the TCP header, excluding options, and assuming a
	 * checksum of zero/
	 */
	old_checksum = th->check;
	th->check = 0;
	sg_set_buf(&sg[block++], th, sizeof(struct tcphdr));
	nbytes += sizeof(struct tcphdr);
#ifdef CONFIG_TCP_MD5SIG_DEBUG
	for (i = 0; i < sizeof (struct tcphdr); i++)
		printk (" %02x", (unsigned int)((unsigned char *)th)[i]);
#endif
	/* 3. the TCP segment data (if any) */
	data_len = tcplen - (th->doff << 2);
	if (data_len > 0) {
		unsigned char *data = (unsigned char *)th + (th->doff << 2);
		sg_set_buf(&sg[block++], data, data_len);
		nbytes += data_len;
	}

	/* 4. an independently-specified key or password, known to both
	 * TCPs and presumably connection-specific
	 */
	sg_set_buf(&sg[block++], key->key, key->keylen);
	nbytes += key->keylen;

#ifdef CONFIG_TCP_MD5SIG_DEBUG
	printk ("  and password: ");
	for (i = 0; i < key->keylen; i++)
		printk ("%02x ", (unsigned int)key->key[i]);
#endif

	/* Now store the Hash into the packet */
	err = crypto_hash_init(desc);
	if (err)
		goto clear_hash;
	err = crypto_hash_update(desc, sg, nbytes);
	if (err)
		goto clear_hash;
	err = crypto_hash_final(desc, md5_hash);
	if (err)
		goto clear_hash;

	/* Reset header, and free up the crypto */
	tcp_put_md5sig_pool();
	th->check = old_checksum;

out:
#ifdef CONFIG_TCP_MD5SIG_DEBUG
	printk(" result:");
	for (i = 0; i < 16; i++)
		printk (" %02x", (unsigned int)(((u8*)md5_hash)[i]));
	printk("\n");
#endif
	return 0;
clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
	goto out;
}

int tcp_v4_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
			 struct sock *sk,
			 struct dst_entry *dst,
			 struct request_sock *req,
			 struct tcphdr *th, int protocol,
			 int tcplen)
{
	__be32 saddr, daddr;

	if (sk) {
		saddr = inet_sk(sk)->saddr;
		daddr = inet_sk(sk)->daddr;
	} else {
		struct rtable *rt = (struct rtable *)dst;
		BUG_ON(!rt);
		saddr = rt->rt_src;
		daddr = rt->rt_dst;
	}
	return tcp_v4_do_calc_md5_hash(md5_hash, key,
				       saddr, daddr,
				       th, protocol, tcplen);
}

EXPORT_SYMBOL(tcp_v4_calc_md5_hash);

static int tcp_v4_inbound_md5_hash (struct sock *sk, struct sk_buff *skb)
{
	/*
	 * This gets called for each TCP segment that arrives
	 * so we want to be efficient.
	 * We have 3 drop cases:
	 * o No MD5 hash and one expected.
	 * o MD5 hash and we're not expecting one.
	 * o MD5 hash and its wrong.
	 */
	__u8 *hash_location = NULL;
	struct tcp_md5sig_key *hash_expected;
	struct iphdr *iph = skb->nh.iph;
	struct tcphdr *th = skb->h.th;
	int length = (th->doff << 2) - sizeof (struct tcphdr);
	int genhash;
	unsigned char *ptr;
	unsigned char newhash[16];

	hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);

	/*
	 * If the TCP option length is less than the TCP_MD5SIG
	 * option length, then we can shortcut
	 */
	if (length < TCPOLEN_MD5SIG) {
		if (hash_expected)
			return 1;
		else
			return 0;
	}

	/* Okay, we can't shortcut - we have to grub through the options */
	ptr = (unsigned char *)(th + 1);
	while (length > 0) {
		int opcode = *ptr++;
		int opsize;

		switch (opcode) {
		case TCPOPT_EOL:
			goto done_opts;
		case TCPOPT_NOP:
			length--;
			continue;
		default:
			opsize = *ptr++;
			if (opsize < 2)
				goto done_opts;
			if (opsize > length)
				goto done_opts;

			if (opcode == TCPOPT_MD5SIG) {
				hash_location = ptr;
				goto done_opts;
			}
		}
		ptr += opsize-2;
		length -= opsize;
	}
done_opts:
	/* We've parsed the options - do we have a hash? */
	if (!hash_expected && !hash_location)
		return 0;

	if (hash_expected && !hash_location) {
		if (net_ratelimit()) {
			printk(KERN_INFO "MD5 Hash NOT expected but found "
			       "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
			       NIPQUAD (iph->saddr), ntohs(th->source),
			       NIPQUAD (iph->daddr), ntohs(th->dest));
		}
		return 1;
	}

	if (!hash_expected && hash_location) {
		if (net_ratelimit()) {
			printk(KERN_INFO "MD5 Hash NOT expected but found "
			       "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
			       NIPQUAD (iph->saddr), ntohs(th->source),
			       NIPQUAD (iph->daddr), ntohs(th->dest));
		}
		return 1;
	}

	/* Okay, so this is hash_expected and hash_location -
	 * so we need to calculate the checksum.
	 */
	genhash = tcp_v4_do_calc_md5_hash(newhash,
					  hash_expected,
					  iph->saddr, iph->daddr,
					  th, sk->sk_protocol,
					  skb->len);

	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
		if (net_ratelimit()) {
			printk(KERN_INFO "MD5 Hash failed for "
			       "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)%s\n",
			       NIPQUAD (iph->saddr), ntohs(th->source),
			       NIPQUAD (iph->daddr), ntohs(th->dest),
			       genhash ? " tcp_v4_calc_md5_hash failed" : "");
#ifdef CONFIG_TCP_MD5SIG_DEBUG
			do {
				int i;
				printk("Received: ");
				for (i = 0; i < 16; i++)
					printk("%02x ", 0xff & (int)hash_location[i]);
				printk("\n");
				printk("Calculated: ");
				for (i = 0; i < 16; i++)
					printk("%02x ", 0xff & (int)newhash[i]);
				printk("\n");
			} while(0);
#endif
		}
		return 1;
	}
	return 0;
}

#endif

1259
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
L
Linus Torvalds 已提交
1260
	.family		=	PF_INET,
1261
	.obj_size	=	sizeof(struct tcp_request_sock),
L
Linus Torvalds 已提交
1262
	.rtx_syn_ack	=	tcp_v4_send_synack,
1263 1264
	.send_ack	=	tcp_v4_reqsk_send_ack,
	.destructor	=	tcp_v4_reqsk_destructor,
L
Linus Torvalds 已提交
1265 1266 1267
	.send_reset	=	tcp_v4_send_reset,
};

1268 1269 1270 1271 1272 1273
struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
#ifdef CONFIG_TCP_MD5SIG
	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
#endif
};

1274 1275 1276
static struct timewait_sock_ops tcp_timewait_sock_ops = {
	.twsk_obj_size	= sizeof(struct tcp_timewait_sock),
	.twsk_unique	= tcp_twsk_unique,
1277
	.twsk_destructor= tcp_twsk_destructor,
1278 1279
};

L
Linus Torvalds 已提交
1280 1281
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
1282
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1283
	struct tcp_options_received tmp_opt;
1284
	struct request_sock *req;
1285 1286
	__be32 saddr = skb->nh.iph->saddr;
	__be32 daddr = skb->nh.iph->daddr;
L
Linus Torvalds 已提交
1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303
	__u32 isn = TCP_SKB_CB(skb)->when;
	struct dst_entry *dst = NULL;
#ifdef CONFIG_SYN_COOKIES
	int want_cookie = 0;
#else
#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
#endif

	/* Never answer to SYNs send to broadcast or multicast */
	if (((struct rtable *)skb->dst)->rt_flags &
	    (RTCF_BROADCAST | RTCF_MULTICAST))
		goto drop;

	/* TW buckets are converted to open requests without
	 * limitations, they conserve resources and peer is
	 * evidently real one.
	 */
1304
	if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
L
Linus Torvalds 已提交
1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317
#ifdef CONFIG_SYN_COOKIES
		if (sysctl_tcp_syncookies) {
			want_cookie = 1;
		} else
#endif
		goto drop;
	}

	/* Accept backlog is full. If we have already queued enough
	 * of warm entries in syn queue, drop request. It is better than
	 * clogging syn queue with openreqs with exponentially increasing
	 * timeout.
	 */
1318
	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
L
Linus Torvalds 已提交
1319 1320
		goto drop;

1321
	req = reqsk_alloc(&tcp_request_sock_ops);
L
Linus Torvalds 已提交
1322 1323 1324
	if (!req)
		goto drop;

1325 1326 1327 1328
#ifdef CONFIG_TCP_MD5SIG
	tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
#endif

L
Linus Torvalds 已提交
1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352
	tcp_clear_options(&tmp_opt);
	tmp_opt.mss_clamp = 536;
	tmp_opt.user_mss  = tcp_sk(sk)->rx_opt.user_mss;

	tcp_parse_options(skb, &tmp_opt, 0);

	if (want_cookie) {
		tcp_clear_options(&tmp_opt);
		tmp_opt.saw_tstamp = 0;
	}

	if (tmp_opt.saw_tstamp && !tmp_opt.rcv_tsval) {
		/* Some OSes (unknown ones, but I see them on web server, which
		 * contains information interesting only for windows'
		 * users) do not send their stamp in SYN. It is easy case.
		 * We simply do not advertise TS support.
		 */
		tmp_opt.saw_tstamp = 0;
		tmp_opt.tstamp_ok  = 0;
	}
	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;

	tcp_openreq_init(req, &tmp_opt, skb);

1353 1354 1355
	if (security_inet_conn_request(sk, skb, req))
		goto drop_and_free;

1356 1357 1358 1359
	ireq = inet_rsk(req);
	ireq->loc_addr = daddr;
	ireq->rmt_addr = saddr;
	ireq->opt = tcp_v4_save_options(sk, skb);
L
Linus Torvalds 已提交
1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380
	if (!want_cookie)
		TCP_ECN_create_request(req, skb->h.th);

	if (want_cookie) {
#ifdef CONFIG_SYN_COOKIES
		syn_flood_warning(skb);
#endif
		isn = cookie_v4_init_sequence(sk, skb, &req->mss);
	} else if (!isn) {
		struct inet_peer *peer = NULL;

		/* VJ's idea. We save last timestamp seen
		 * from the destination in peer table, when entering
		 * state TIME-WAIT, and check against it before
		 * accepting new connection request.
		 *
		 * If "isn" is not zero, this request hit alive
		 * timewait bucket, so that all the necessary checks
		 * are made in the function processing timewait state.
		 */
		if (tmp_opt.saw_tstamp &&
1381
		    tcp_death_row.sysctl_tw_recycle &&
1382
		    (dst = inet_csk_route_req(sk, req)) != NULL &&
L
Linus Torvalds 已提交
1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394
		    (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
		    peer->v4daddr == saddr) {
			if (xtime.tv_sec < peer->tcp_ts_stamp + TCP_PAWS_MSL &&
			    (s32)(peer->tcp_ts - req->ts_recent) >
							TCP_PAWS_WINDOW) {
				NET_INC_STATS_BH(LINUX_MIB_PAWSPASSIVEREJECTED);
				dst_release(dst);
				goto drop_and_free;
			}
		}
		/* Kill the following clause, if you dislike this way. */
		else if (!sysctl_tcp_syncookies &&
1395
			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
L
Linus Torvalds 已提交
1396 1397 1398 1399 1400 1401 1402 1403 1404 1405
			  (sysctl_max_syn_backlog >> 2)) &&
			 (!peer || !peer->tcp_ts_stamp) &&
			 (!dst || !dst_metric(dst, RTAX_RTT))) {
			/* Without syncookies last quarter of
			 * backlog is filled with destinations,
			 * proven to be alive.
			 * It means that we continue to communicate
			 * to destinations, already remembered
			 * to the moment of synflood.
			 */
1406 1407 1408 1409
			LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open "
				       "request from %u.%u.%u.%u/%u\n",
				       NIPQUAD(saddr),
				       ntohs(skb->h.th->source));
L
Linus Torvalds 已提交
1410 1411 1412 1413
			dst_release(dst);
			goto drop_and_free;
		}

1414
		isn = tcp_v4_init_sequence(skb);
L
Linus Torvalds 已提交
1415
	}
1416
	tcp_rsk(req)->snt_isn = isn;
L
Linus Torvalds 已提交
1417 1418 1419 1420 1421

	if (tcp_v4_send_synack(sk, req, dst))
		goto drop_and_free;

	if (want_cookie) {
1422
	   	reqsk_free(req);
L
Linus Torvalds 已提交
1423
	} else {
1424
		inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
L
Linus Torvalds 已提交
1425 1426 1427 1428
	}
	return 0;

drop_and_free:
1429
	reqsk_free(req);
L
Linus Torvalds 已提交
1430 1431 1432 1433 1434 1435 1436 1437 1438 1439
drop:
	return 0;
}


/*
 * The three way handshake has completed - we got a valid synack -
 * now create the new socket.
 */
struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1440
				  struct request_sock *req,
L
Linus Torvalds 已提交
1441 1442
				  struct dst_entry *dst)
{
1443
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1444 1445 1446
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
1447 1448 1449
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
L
Linus Torvalds 已提交
1450 1451 1452 1453

	if (sk_acceptq_is_full(sk))
		goto exit_overflow;

1454
	if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
L
Linus Torvalds 已提交
1455 1456 1457 1458 1459 1460
		goto exit;

	newsk = tcp_create_openreq_child(sk, req, skb);
	if (!newsk)
		goto exit;

1461
	newsk->sk_gso_type = SKB_GSO_TCPV4;
1462
	sk_setup_caps(newsk, dst);
L
Linus Torvalds 已提交
1463 1464 1465

	newtp		      = tcp_sk(newsk);
	newinet		      = inet_sk(newsk);
1466 1467 1468 1469 1470 1471
	ireq		      = inet_rsk(req);
	newinet->daddr	      = ireq->rmt_addr;
	newinet->rcv_saddr    = ireq->loc_addr;
	newinet->saddr	      = ireq->loc_addr;
	newinet->opt	      = ireq->opt;
	ireq->opt	      = NULL;
1472
	newinet->mc_index     = inet_iif(skb);
L
Linus Torvalds 已提交
1473
	newinet->mc_ttl	      = skb->nh.iph->ttl;
1474
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
L
Linus Torvalds 已提交
1475
	if (newinet->opt)
1476
		inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
L
Linus Torvalds 已提交
1477 1478
	newinet->id = newtp->write_seq ^ jiffies;

J
John Heffner 已提交
1479
	tcp_mtup_init(newsk);
L
Linus Torvalds 已提交
1480 1481 1482 1483
	tcp_sync_mss(newsk, dst_mtu(dst));
	newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
	tcp_initialize_rcv_mss(newsk);

1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501
#ifdef CONFIG_TCP_MD5SIG
	/* Copy over the MD5 key from the original socket */
	if ((key = tcp_v4_md5_do_lookup(sk, newinet->daddr)) != NULL) {
		/*
		 * We're using one, so create a matching key
		 * on the newsk structure. If we fail to get
		 * memory, then we end up not copying the key
		 * across. Shucks.
		 */
		char *newkey = kmalloc(key->keylen, GFP_ATOMIC);
		if (newkey) {
			memcpy(newkey, key->key, key->keylen);
			tcp_v4_md5_do_add(newsk, inet_sk(sk)->daddr,
					  newkey, key->keylen);
		}
	}
#endif

1502
	__inet_hash(&tcp_hashinfo, newsk, 0);
1503
	__inet_inherit_port(&tcp_hashinfo, sk, newsk);
L
Linus Torvalds 已提交
1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519

	return newsk;

exit_overflow:
	NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
exit:
	NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
	dst_release(dst);
	return NULL;
}

static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
{
	struct tcphdr *th = skb->h.th;
	struct iphdr *iph = skb->nh.iph;
	struct sock *nsk;
1520
	struct request_sock **prev;
L
Linus Torvalds 已提交
1521
	/* Find possible connection requests. */
1522 1523
	struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
						       iph->saddr, iph->daddr);
L
Linus Torvalds 已提交
1524 1525 1526
	if (req)
		return tcp_check_req(sk, skb, req, prev);

1527 1528 1529
	nsk = inet_lookup_established(&tcp_hashinfo, skb->nh.iph->saddr,
				      th->source, skb->nh.iph->daddr,
				      th->dest, inet_iif(skb));
L
Linus Torvalds 已提交
1530 1531 1532 1533 1534 1535

	if (nsk) {
		if (nsk->sk_state != TCP_TIME_WAIT) {
			bh_lock_sock(nsk);
			return nsk;
		}
1536
		inet_twsk_put(inet_twsk(nsk));
L
Linus Torvalds 已提交
1537 1538 1539 1540 1541 1542 1543 1544 1545 1546
		return NULL;
	}

#ifdef CONFIG_SYN_COOKIES
	if (!th->rst && !th->syn && th->ack)
		sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
#endif
	return sk;
}

1547
static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
L
Linus Torvalds 已提交
1548
{
1549
	if (skb->ip_summed == CHECKSUM_COMPLETE) {
L
Linus Torvalds 已提交
1550
		if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
1551 1552
				  skb->nh.iph->daddr, skb->csum)) {
			skb->ip_summed = CHECKSUM_UNNECESSARY;
L
Linus Torvalds 已提交
1553
			return 0;
1554
		}
L
Linus Torvalds 已提交
1555
	}
1556 1557 1558 1559

	skb->csum = csum_tcpudp_nofold(skb->nh.iph->saddr, skb->nh.iph->daddr,
				       skb->len, IPPROTO_TCP, 0);

L
Linus Torvalds 已提交
1560
	if (skb->len <= 76) {
1561
		return __skb_checksum_complete(skb);
L
Linus Torvalds 已提交
1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
	}
	return 0;
}


/* The socket must have it's spinlock held when we get
 * here.
 *
 * We have a potential double-lock case here, so even when
 * doing backlog processing we use the BH locking scheme.
 * This is because we cannot sleep with the original spinlock
 * held.
 */
int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
{
1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588
	struct sock *rsk;
#ifdef CONFIG_TCP_MD5SIG
	/*
	 * We really want to reject the packet as early as possible
	 * if:
	 *  o We're expecting an MD5'd packet and this is no MD5 tcp option
	 *  o There is an MD5 option and we're not expecting one
	 */
	if (tcp_v4_inbound_md5_hash (sk, skb))
		goto discard;
#endif

L
Linus Torvalds 已提交
1589 1590
	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
		TCP_CHECK_TIMER(sk);
1591 1592
		if (tcp_rcv_established(sk, skb, skb->h.th, skb->len)) {
			rsk = sk;
L
Linus Torvalds 已提交
1593
			goto reset;
1594
		}
L
Linus Torvalds 已提交
1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607
		TCP_CHECK_TIMER(sk);
		return 0;
	}

	if (skb->len < (skb->h.th->doff << 2) || tcp_checksum_complete(skb))
		goto csum_err;

	if (sk->sk_state == TCP_LISTEN) {
		struct sock *nsk = tcp_v4_hnd_req(sk, skb);
		if (!nsk)
			goto discard;

		if (nsk != sk) {
1608 1609
			if (tcp_child_process(sk, nsk, skb)) {
				rsk = nsk;
L
Linus Torvalds 已提交
1610
				goto reset;
1611
			}
L
Linus Torvalds 已提交
1612 1613 1614 1615 1616
			return 0;
		}
	}

	TCP_CHECK_TIMER(sk);
1617 1618
	if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len)) {
		rsk = sk;
L
Linus Torvalds 已提交
1619
		goto reset;
1620
	}
L
Linus Torvalds 已提交
1621 1622 1623 1624
	TCP_CHECK_TIMER(sk);
	return 0;

reset:
1625
	tcp_v4_send_reset(rsk, skb);
L
Linus Torvalds 已提交
1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667
discard:
	kfree_skb(skb);
	/* Be careful here. If this function gets more complicated and
	 * gcc suffers from register pressure on the x86, sk (in %ebx)
	 * might be destroyed here. This current version compiles correctly,
	 * but you have been warned.
	 */
	return 0;

csum_err:
	TCP_INC_STATS_BH(TCP_MIB_INERRS);
	goto discard;
}

/*
 *	From tcp_input.c
 */

int tcp_v4_rcv(struct sk_buff *skb)
{
	struct tcphdr *th;
	struct sock *sk;
	int ret;

	if (skb->pkt_type != PACKET_HOST)
		goto discard_it;

	/* Count it even if it's bad */
	TCP_INC_STATS_BH(TCP_MIB_INSEGS);

	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
		goto discard_it;

	th = skb->h.th;

	if (th->doff < sizeof(struct tcphdr) / 4)
		goto bad_packet;
	if (!pskb_may_pull(skb, th->doff * 4))
		goto discard_it;

	/* An explanation is required here, I think.
	 * Packet length and doff are validated by header prediction,
S
Stephen Hemminger 已提交
1668
	 * provided case of th->doff==0 is eliminated.
L
Linus Torvalds 已提交
1669 1670
	 * So, we defer the checks. */
	if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
1671
	     tcp_v4_checksum_init(skb)))
L
Linus Torvalds 已提交
1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682
		goto bad_packet;

	th = skb->h.th;
	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
				    skb->len - th->doff * 4);
	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
	TCP_SKB_CB(skb)->when	 = 0;
	TCP_SKB_CB(skb)->flags	 = skb->nh.iph->tos;
	TCP_SKB_CB(skb)->sacked	 = 0;

1683
	sk = __inet_lookup(&tcp_hashinfo, skb->nh.iph->saddr, th->source,
1684
			   skb->nh.iph->daddr, th->dest,
1685
			   inet_iif(skb));
L
Linus Torvalds 已提交
1686 1687 1688 1689 1690 1691 1692 1693 1694 1695

	if (!sk)
		goto no_tcp_socket;

process:
	if (sk->sk_state == TCP_TIME_WAIT)
		goto do_time_wait;

	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;
1696
	nf_reset(skb);
L
Linus Torvalds 已提交
1697

1698
	if (sk_filter(sk, skb))
L
Linus Torvalds 已提交
1699 1700 1701 1702
		goto discard_and_relse;

	skb->dev = NULL;

1703
	bh_lock_sock_nested(sk);
L
Linus Torvalds 已提交
1704 1705
	ret = 0;
	if (!sock_owned_by_user(sk)) {
C
Chris Leech 已提交
1706 1707 1708 1709 1710
#ifdef CONFIG_NET_DMA
		struct tcp_sock *tp = tcp_sk(sk);
		if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
			tp->ucopy.dma_chan = get_softnet_dma();
		if (tp->ucopy.dma_chan)
L
Linus Torvalds 已提交
1711
			ret = tcp_v4_do_rcv(sk, skb);
C
Chris Leech 已提交
1712 1713 1714 1715 1716 1717
		else
#endif
		{
			if (!tcp_prequeue(sk, skb))
			ret = tcp_v4_do_rcv(sk, skb);
		}
L
Linus Torvalds 已提交
1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733
	} else
		sk_add_backlog(sk, skb);
	bh_unlock_sock(sk);

	sock_put(sk);

	return ret;

no_tcp_socket:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto discard_it;

	if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
bad_packet:
		TCP_INC_STATS_BH(TCP_MIB_INERRS);
	} else {
1734
		tcp_v4_send_reset(NULL, skb);
L
Linus Torvalds 已提交
1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747
	}

discard_it:
	/* Discard frame. */
	kfree_skb(skb);
  	return 0;

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1748
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1749 1750 1751 1752 1753
		goto discard_it;
	}

	if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
		TCP_INC_STATS_BH(TCP_MIB_INERRS);
1754
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1755 1756
		goto discard_it;
	}
1757
	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
L
Linus Torvalds 已提交
1758
	case TCP_TW_SYN: {
1759 1760
		struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo,
							skb->nh.iph->daddr,
1761
							th->dest,
1762
							inet_iif(skb));
L
Linus Torvalds 已提交
1763
		if (sk2) {
1764 1765
			inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
			inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818
			sk = sk2;
			goto process;
		}
		/* Fall through to ACK */
	}
	case TCP_TW_ACK:
		tcp_v4_timewait_ack(sk, skb);
		break;
	case TCP_TW_RST:
		goto no_tcp_socket;
	case TCP_TW_SUCCESS:;
	}
	goto discard_it;
}

/* VJ's idea. Save last timestamp seen from this destination
 * and hold it at least for normal timewait interval to use for duplicate
 * segment detection in subsequent connections, before they enter synchronized
 * state.
 */

int tcp_v4_remember_stamp(struct sock *sk)
{
	struct inet_sock *inet = inet_sk(sk);
	struct tcp_sock *tp = tcp_sk(sk);
	struct rtable *rt = (struct rtable *)__sk_dst_get(sk);
	struct inet_peer *peer = NULL;
	int release_it = 0;

	if (!rt || rt->rt_dst != inet->daddr) {
		peer = inet_getpeer(inet->daddr, 1);
		release_it = 1;
	} else {
		if (!rt->peer)
			rt_bind_peer(rt, 1);
		peer = rt->peer;
	}

	if (peer) {
		if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
		    (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
		     peer->tcp_ts_stamp <= tp->rx_opt.ts_recent_stamp)) {
			peer->tcp_ts_stamp = tp->rx_opt.ts_recent_stamp;
			peer->tcp_ts = tp->rx_opt.ts_recent;
		}
		if (release_it)
			inet_putpeer(peer);
		return 1;
	}

	return 0;
}

1819
int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw)
L
Linus Torvalds 已提交
1820
{
1821
	struct inet_peer *peer = inet_getpeer(tw->tw_daddr, 1);
L
Linus Torvalds 已提交
1822 1823

	if (peer) {
1824 1825 1826
		const struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);

		if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
L
Linus Torvalds 已提交
1827
		    (peer->tcp_ts_stamp + TCP_PAWS_MSL < xtime.tv_sec &&
1828 1829 1830
		     peer->tcp_ts_stamp <= tcptw->tw_ts_recent_stamp)) {
			peer->tcp_ts_stamp = tcptw->tw_ts_recent_stamp;
			peer->tcp_ts	   = tcptw->tw_ts_recent;
L
Linus Torvalds 已提交
1831 1832 1833 1834 1835 1836 1837 1838
		}
		inet_putpeer(peer);
		return 1;
	}

	return 0;
}

1839
struct inet_connection_sock_af_ops ipv4_specific = {
1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
	.conn_request	   = tcp_v4_conn_request,
	.syn_recv_sock	   = tcp_v4_syn_recv_sock,
	.remember_stamp	   = tcp_v4_remember_stamp,
	.net_header_len	   = sizeof(struct iphdr),
	.setsockopt	   = ip_setsockopt,
	.getsockopt	   = ip_getsockopt,
	.addr2sockaddr	   = inet_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in),
1851
#ifdef CONFIG_COMPAT
1852 1853
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
1854
#endif
L
Linus Torvalds 已提交
1855 1856
};

1857 1858 1859 1860 1861 1862 1863 1864 1865
struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
#ifdef CONFIG_TCP_MD5SIG
	.md5_lookup		= tcp_v4_md5_lookup,
	.calc_md5_hash		= tcp_v4_calc_md5_hash,
	.md5_add		= tcp_v4_md5_add_func,
	.md5_parse		= tcp_v4_parse_md5_keys,
#endif
};

L
Linus Torvalds 已提交
1866 1867 1868 1869 1870
/* NOTE: A lot of things set to zero explicitly by call to
 *       sk_alloc() so need not be done here.
 */
static int tcp_v4_init_sock(struct sock *sk)
{
1871
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1872 1873 1874 1875 1876 1877
	struct tcp_sock *tp = tcp_sk(sk);

	skb_queue_head_init(&tp->out_of_order_queue);
	tcp_init_xmit_timers(sk);
	tcp_prequeue_init(tp);

1878
	icsk->icsk_rto = TCP_TIMEOUT_INIT;
L
Linus Torvalds 已提交
1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892
	tp->mdev = TCP_TIMEOUT_INIT;

	/* So many TCP implementations out there (incorrectly) count the
	 * initial SYN frame in their delayed-ACK and congestion control
	 * algorithms that we must have the following bandaid to talk
	 * efficiently to them.  -DaveM
	 */
	tp->snd_cwnd = 2;

	/* See draft-stevens-tcpca-spec-01 for discussion of the
	 * initialization of these values.
	 */
	tp->snd_ssthresh = 0x7fffffff;	/* Infinity */
	tp->snd_cwnd_clamp = ~0;
1893
	tp->mss_cache = 536;
L
Linus Torvalds 已提交
1894 1895

	tp->reordering = sysctl_tcp_reordering;
1896
	icsk->icsk_ca_ops = &tcp_init_congestion_ops;
L
Linus Torvalds 已提交
1897 1898 1899 1900 1901 1902

	sk->sk_state = TCP_CLOSE;

	sk->sk_write_space = sk_stream_write_space;
	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);

1903
	icsk->icsk_af_ops = &ipv4_specific;
1904
	icsk->icsk_sync_mss = tcp_sync_mss;
1905 1906 1907
#ifdef CONFIG_TCP_MD5SIG
	tp->af_specific = &tcp_sock_ipv4_specific;
#endif
L
Linus Torvalds 已提交
1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922

	sk->sk_sndbuf = sysctl_tcp_wmem[1];
	sk->sk_rcvbuf = sysctl_tcp_rmem[1];

	atomic_inc(&tcp_sockets_allocated);

	return 0;
}

int tcp_v4_destroy_sock(struct sock *sk)
{
	struct tcp_sock *tp = tcp_sk(sk);

	tcp_clear_xmit_timers(sk);

1923
	tcp_cleanup_congestion_control(sk);
1924

L
Linus Torvalds 已提交
1925 1926 1927 1928 1929 1930
	/* Cleanup up the write buffer. */
  	sk_stream_writequeue_purge(sk);

	/* Cleans up our, hopefully empty, out_of_order_queue. */
  	__skb_queue_purge(&tp->out_of_order_queue);

1931 1932 1933 1934 1935 1936 1937 1938 1939
#ifdef CONFIG_TCP_MD5SIG
	/* Clean up the MD5 key list, if any */
	if (tp->md5sig_info) {
		tcp_v4_clear_md5_list(sk);
		kfree(tp->md5sig_info);
		tp->md5sig_info = NULL;
	}
#endif

C
Chris Leech 已提交
1940 1941 1942 1943 1944
#ifdef CONFIG_NET_DMA
	/* Cleans up our sk_async_wait_queue */
  	__skb_queue_purge(&sk->sk_async_wait_queue);
#endif

L
Linus Torvalds 已提交
1945 1946 1947 1948
	/* Clean prequeue, it must be empty really */
	__skb_queue_purge(&tp->ucopy.prequeue);

	/* Clean up a referenced TCP bind bucket. */
1949
	if (inet_csk(sk)->icsk_bind_hash)
1950
		inet_put_port(&tcp_hashinfo, sk);
L
Linus Torvalds 已提交
1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969

	/*
	 * If sendmsg cached page exists, toss it.
	 */
	if (sk->sk_sndmsg_page) {
		__free_page(sk->sk_sndmsg_page);
		sk->sk_sndmsg_page = NULL;
	}

	atomic_dec(&tcp_sockets_allocated);

	return 0;
}

EXPORT_SYMBOL(tcp_v4_destroy_sock);

#ifdef CONFIG_PROC_FS
/* Proc filesystem TCP sock list dumping. */

1970
static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
L
Linus Torvalds 已提交
1971 1972
{
	return hlist_empty(head) ? NULL :
1973
		list_entry(head->first, struct inet_timewait_sock, tw_node);
L
Linus Torvalds 已提交
1974 1975
}

1976
static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
L
Linus Torvalds 已提交
1977 1978 1979 1980 1981 1982 1983
{
	return tw->tw_node.next ?
		hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
}

static void *listening_get_next(struct seq_file *seq, void *cur)
{
1984
	struct inet_connection_sock *icsk;
L
Linus Torvalds 已提交
1985 1986 1987 1988 1989 1990
	struct hlist_node *node;
	struct sock *sk = cur;
	struct tcp_iter_state* st = seq->private;

	if (!sk) {
		st->bucket = 0;
1991
		sk = sk_head(&tcp_hashinfo.listening_hash[0]);
L
Linus Torvalds 已提交
1992 1993 1994 1995 1996 1997
		goto get_sk;
	}

	++st->num;

	if (st->state == TCP_SEQ_STATE_OPENREQ) {
1998
		struct request_sock *req = cur;
L
Linus Torvalds 已提交
1999

2000
		icsk = inet_csk(st->syn_wait_sk);
L
Linus Torvalds 已提交
2001 2002 2003
		req = req->dl_next;
		while (1) {
			while (req) {
2004
				if (req->rsk_ops->family == st->family) {
L
Linus Torvalds 已提交
2005 2006 2007 2008 2009
					cur = req;
					goto out;
				}
				req = req->dl_next;
			}
2010
			if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
L
Linus Torvalds 已提交
2011 2012
				break;
get_req:
2013
			req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
L
Linus Torvalds 已提交
2014 2015 2016
		}
		sk	  = sk_next(st->syn_wait_sk);
		st->state = TCP_SEQ_STATE_LISTENING;
2017
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2018
	} else {
2019 2020 2021
	       	icsk = inet_csk(sk);
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue))
L
Linus Torvalds 已提交
2022
			goto start_req;
2023
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2024 2025 2026 2027 2028 2029 2030 2031
		sk = sk_next(sk);
	}
get_sk:
	sk_for_each_from(sk, node) {
		if (sk->sk_family == st->family) {
			cur = sk;
			goto out;
		}
2032 2033 2034
	       	icsk = inet_csk(sk);
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
L
Linus Torvalds 已提交
2035 2036 2037 2038 2039 2040 2041
start_req:
			st->uid		= sock_i_uid(sk);
			st->syn_wait_sk = sk;
			st->state	= TCP_SEQ_STATE_OPENREQ;
			st->sbucket	= 0;
			goto get_req;
		}
2042
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2043
	}
2044
	if (++st->bucket < INET_LHTABLE_SIZE) {
2045
		sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
L
Linus Torvalds 已提交
2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068
		goto get_sk;
	}
	cur = NULL;
out:
	return cur;
}

static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
{
	void *rc = listening_get_next(seq, NULL);

	while (rc && *pos) {
		rc = listening_get_next(seq, rc);
		--*pos;
	}
	return rc;
}

static void *established_get_first(struct seq_file *seq)
{
	struct tcp_iter_state* st = seq->private;
	void *rc = NULL;

2069
	for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
L
Linus Torvalds 已提交
2070 2071
		struct sock *sk;
		struct hlist_node *node;
2072
		struct inet_timewait_sock *tw;
L
Linus Torvalds 已提交
2073 2074 2075 2076

		/* We can reschedule _before_ having picked the target: */
		cond_resched_softirq();

2077 2078
		read_lock(&tcp_hashinfo.ehash[st->bucket].lock);
		sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
L
Linus Torvalds 已提交
2079 2080 2081 2082 2083 2084 2085
			if (sk->sk_family != st->family) {
				continue;
			}
			rc = sk;
			goto out;
		}
		st->state = TCP_SEQ_STATE_TIME_WAIT;
2086 2087
		inet_twsk_for_each(tw, node,
				   &tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain) {
L
Linus Torvalds 已提交
2088 2089 2090 2091 2092 2093
			if (tw->tw_family != st->family) {
				continue;
			}
			rc = tw;
			goto out;
		}
2094
		read_unlock(&tcp_hashinfo.ehash[st->bucket].lock);
L
Linus Torvalds 已提交
2095 2096 2097 2098 2099 2100 2101 2102 2103
		st->state = TCP_SEQ_STATE_ESTABLISHED;
	}
out:
	return rc;
}

static void *established_get_next(struct seq_file *seq, void *cur)
{
	struct sock *sk = cur;
2104
	struct inet_timewait_sock *tw;
L
Linus Torvalds 已提交
2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120
	struct hlist_node *node;
	struct tcp_iter_state* st = seq->private;

	++st->num;

	if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
		tw = cur;
		tw = tw_next(tw);
get_tw:
		while (tw && tw->tw_family != st->family) {
			tw = tw_next(tw);
		}
		if (tw) {
			cur = tw;
			goto out;
		}
2121
		read_unlock(&tcp_hashinfo.ehash[st->bucket].lock);
L
Linus Torvalds 已提交
2122 2123 2124 2125 2126
		st->state = TCP_SEQ_STATE_ESTABLISHED;

		/* We can reschedule between buckets: */
		cond_resched_softirq();

2127 2128 2129
		if (++st->bucket < tcp_hashinfo.ehash_size) {
			read_lock(&tcp_hashinfo.ehash[st->bucket].lock);
			sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
L
Linus Torvalds 已提交
2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142
		} else {
			cur = NULL;
			goto out;
		}
	} else
		sk = sk_next(sk);

	sk_for_each_from(sk, node) {
		if (sk->sk_family == st->family)
			goto found;
	}

	st->state = TCP_SEQ_STATE_TIME_WAIT;
2143
	tw = tw_head(&tcp_hashinfo.ehash[st->bucket + tcp_hashinfo.ehash_size].chain);
L
Linus Torvalds 已提交
2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166
	goto get_tw;
found:
	cur = sk;
out:
	return cur;
}

static void *established_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc = established_get_first(seq);

	while (rc && pos) {
		rc = established_get_next(seq, rc);
		--pos;
	}		
	return rc;
}

static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
	struct tcp_iter_state* st = seq->private;

2167
	inet_listen_lock(&tcp_hashinfo);
L
Linus Torvalds 已提交
2168 2169 2170 2171
	st->state = TCP_SEQ_STATE_LISTENING;
	rc	  = listening_get_idx(seq, &pos);

	if (!rc) {
2172
		inet_listen_unlock(&tcp_hashinfo);
L
Linus Torvalds 已提交
2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204
		local_bh_disable();
		st->state = TCP_SEQ_STATE_ESTABLISHED;
		rc	  = established_get_idx(seq, pos);
	}

	return rc;
}

static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
{
	struct tcp_iter_state* st = seq->private;
	st->state = TCP_SEQ_STATE_LISTENING;
	st->num = 0;
	return *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	void *rc = NULL;
	struct tcp_iter_state* st;

	if (v == SEQ_START_TOKEN) {
		rc = tcp_get_idx(seq, 0);
		goto out;
	}
	st = seq->private;

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
	case TCP_SEQ_STATE_LISTENING:
		rc = listening_get_next(seq, v);
		if (!rc) {
2205
			inet_listen_unlock(&tcp_hashinfo);
L
Linus Torvalds 已提交
2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227
			local_bh_disable();
			st->state = TCP_SEQ_STATE_ESTABLISHED;
			rc	  = established_get_first(seq);
		}
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
	case TCP_SEQ_STATE_TIME_WAIT:
		rc = established_get_next(seq, v);
		break;
	}
out:
	++*pos;
	return rc;
}

static void tcp_seq_stop(struct seq_file *seq, void *v)
{
	struct tcp_iter_state* st = seq->private;

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
		if (v) {
2228 2229
			struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
			read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2230 2231 2232
		}
	case TCP_SEQ_STATE_LISTENING:
		if (v != SEQ_START_TOKEN)
2233
			inet_listen_unlock(&tcp_hashinfo);
L
Linus Torvalds 已提交
2234 2235 2236 2237
		break;
	case TCP_SEQ_STATE_TIME_WAIT:
	case TCP_SEQ_STATE_ESTABLISHED:
		if (v)
2238
			read_unlock(&tcp_hashinfo.ehash[st->bucket].lock);
L
Linus Torvalds 已提交
2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253
		local_bh_enable();
		break;
	}
}

static int tcp_seq_open(struct inode *inode, struct file *file)
{
	struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
	struct seq_file *seq;
	struct tcp_iter_state *s;
	int rc;

	if (unlikely(afinfo == NULL))
		return -EINVAL;

2254
	s = kzalloc(sizeof(*s), GFP_KERNEL);
L
Linus Torvalds 已提交
2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303
	if (!s)
		return -ENOMEM;
	s->family		= afinfo->family;
	s->seq_ops.start	= tcp_seq_start;
	s->seq_ops.next		= tcp_seq_next;
	s->seq_ops.show		= afinfo->seq_show;
	s->seq_ops.stop		= tcp_seq_stop;

	rc = seq_open(file, &s->seq_ops);
	if (rc)
		goto out_kfree;
	seq	     = file->private_data;
	seq->private = s;
out:
	return rc;
out_kfree:
	kfree(s);
	goto out;
}

int tcp_proc_register(struct tcp_seq_afinfo *afinfo)
{
	int rc = 0;
	struct proc_dir_entry *p;

	if (!afinfo)
		return -EINVAL;
	afinfo->seq_fops->owner		= afinfo->owner;
	afinfo->seq_fops->open		= tcp_seq_open;
	afinfo->seq_fops->read		= seq_read;
	afinfo->seq_fops->llseek	= seq_lseek;
	afinfo->seq_fops->release	= seq_release_private;
	
	p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
	if (p)
		p->data = afinfo;
	else
		rc = -ENOMEM;
	return rc;
}

void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo)
{
	if (!afinfo)
		return;
	proc_net_remove(afinfo->name);
	memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops)); 
}

2304
static void get_openreq4(struct sock *sk, struct request_sock *req,
L
Linus Torvalds 已提交
2305 2306
			 char *tmpbuf, int i, int uid)
{
2307
	const struct inet_request_sock *ireq = inet_rsk(req);
L
Linus Torvalds 已提交
2308 2309 2310 2311 2312
	int ttd = req->expires - jiffies;

	sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p",
		i,
2313
		ireq->loc_addr,
L
Linus Torvalds 已提交
2314
		ntohs(inet_sk(sk)->sport),
2315 2316
		ireq->rmt_addr,
		ntohs(ireq->rmt_port),
L
Linus Torvalds 已提交
2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333
		TCP_SYN_RECV,
		0, 0, /* could print option size, but that is af dependent. */
		1,    /* timers active (only the expire timer) */
		jiffies_to_clock_t(ttd),
		req->retrans,
		uid,
		0,  /* non standard timer */
		0, /* open_requests have no inode */
		atomic_read(&sk->sk_refcnt),
		req);
}

static void get_tcp4_sock(struct sock *sp, char *tmpbuf, int i)
{
	int timer_active;
	unsigned long timer_expires;
	struct tcp_sock *tp = tcp_sk(sp);
2334
	const struct inet_connection_sock *icsk = inet_csk(sp);
L
Linus Torvalds 已提交
2335
	struct inet_sock *inet = inet_sk(sp);
2336 2337
	__be32 dest = inet->daddr;
	__be32 src = inet->rcv_saddr;
L
Linus Torvalds 已提交
2338 2339 2340
	__u16 destp = ntohs(inet->dport);
	__u16 srcp = ntohs(inet->sport);

2341
	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
L
Linus Torvalds 已提交
2342
		timer_active	= 1;
2343 2344
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
Linus Torvalds 已提交
2345
		timer_active	= 4;
2346
		timer_expires	= icsk->icsk_timeout;
L
Linus Torvalds 已提交
2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357
	} else if (timer_pending(&sp->sk_timer)) {
		timer_active	= 2;
		timer_expires	= sp->sk_timer.expires;
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

	sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
			"%08X %5d %8d %lu %d %p %u %u %u %u %d",
		i, src, srcp, dest, destp, sp->sk_state,
2358 2359
		tp->write_seq - tp->snd_una,
		(sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
L
Linus Torvalds 已提交
2360 2361
		timer_active,
		jiffies_to_clock_t(timer_expires - jiffies),
2362
		icsk->icsk_retransmits,
L
Linus Torvalds 已提交
2363
		sock_i_uid(sp),
2364
		icsk->icsk_probes_out,
L
Linus Torvalds 已提交
2365 2366
		sock_i_ino(sp),
		atomic_read(&sp->sk_refcnt), sp,
2367 2368 2369
		icsk->icsk_rto,
		icsk->icsk_ack.ato,
		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
L
Linus Torvalds 已提交
2370 2371 2372 2373
		tp->snd_cwnd,
		tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh);
}

2374
static void get_timewait4_sock(struct inet_timewait_sock *tw, char *tmpbuf, int i)
L
Linus Torvalds 已提交
2375
{
2376
	__be32 dest, src;
L
Linus Torvalds 已提交
2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453
	__u16 destp, srcp;
	int ttd = tw->tw_ttd - jiffies;

	if (ttd < 0)
		ttd = 0;

	dest  = tw->tw_daddr;
	src   = tw->tw_rcv_saddr;
	destp = ntohs(tw->tw_dport);
	srcp  = ntohs(tw->tw_sport);

	sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p",
		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
		3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
		atomic_read(&tw->tw_refcnt), tw);
}

#define TMPSZ 150

static int tcp4_seq_show(struct seq_file *seq, void *v)
{
	struct tcp_iter_state* st;
	char tmpbuf[TMPSZ + 1];

	if (v == SEQ_START_TOKEN) {
		seq_printf(seq, "%-*s\n", TMPSZ - 1,
			   "  sl  local_address rem_address   st tx_queue "
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
			   "inode");
		goto out;
	}
	st = seq->private;

	switch (st->state) {
	case TCP_SEQ_STATE_LISTENING:
	case TCP_SEQ_STATE_ESTABLISHED:
		get_tcp4_sock(v, tmpbuf, st->num);
		break;
	case TCP_SEQ_STATE_OPENREQ:
		get_openreq4(st->syn_wait_sk, v, tmpbuf, st->num, st->uid);
		break;
	case TCP_SEQ_STATE_TIME_WAIT:
		get_timewait4_sock(v, tmpbuf, st->num);
		break;
	}
	seq_printf(seq, "%-*s\n", TMPSZ - 1, tmpbuf);
out:
	return 0;
}

static struct file_operations tcp4_seq_fops;
static struct tcp_seq_afinfo tcp4_seq_afinfo = {
	.owner		= THIS_MODULE,
	.name		= "tcp",
	.family		= AF_INET,
	.seq_show	= tcp4_seq_show,
	.seq_fops	= &tcp4_seq_fops,
};

int __init tcp4_proc_init(void)
{
	return tcp_proc_register(&tcp4_seq_afinfo);
}

void tcp4_proc_exit(void)
{
	tcp_proc_unregister(&tcp4_seq_afinfo);
}
#endif /* CONFIG_PROC_FS */

struct proto tcp_prot = {
	.name			= "TCP",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v4_connect,
	.disconnect		= tcp_disconnect,
2454
	.accept			= inet_csk_accept,
L
Linus Torvalds 已提交
2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468
	.ioctl			= tcp_ioctl,
	.init			= tcp_v4_init_sock,
	.destroy		= tcp_v4_destroy_sock,
	.shutdown		= tcp_shutdown,
	.setsockopt		= tcp_setsockopt,
	.getsockopt		= tcp_getsockopt,
	.sendmsg		= tcp_sendmsg,
	.recvmsg		= tcp_recvmsg,
	.backlog_rcv		= tcp_v4_do_rcv,
	.hash			= tcp_v4_hash,
	.unhash			= tcp_unhash,
	.get_port		= tcp_v4_get_port,
	.enter_memory_pressure	= tcp_enter_memory_pressure,
	.sockets_allocated	= &tcp_sockets_allocated,
2469
	.orphan_count		= &tcp_orphan_count,
L
Linus Torvalds 已提交
2470 2471 2472 2473 2474 2475 2476
	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
	.sysctl_mem		= sysctl_tcp_mem,
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp_sock),
2477
	.twsk_prot		= &tcp_timewait_sock_ops,
2478
	.rsk_prot		= &tcp_request_sock_ops,
2479 2480 2481 2482
#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
#endif
L
Linus Torvalds 已提交
2483 2484 2485 2486
};

void __init tcp_v4_init(struct net_proto_family *ops)
{
2487
	if (inet_csk_ctl_sock_create(&tcp_socket, PF_INET, SOCK_RAW, IPPROTO_TCP) < 0)
L
Linus Torvalds 已提交
2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508
		panic("Failed to create the TCP control socket.\n");
}

EXPORT_SYMBOL(ipv4_specific);
EXPORT_SYMBOL(tcp_hashinfo);
EXPORT_SYMBOL(tcp_prot);
EXPORT_SYMBOL(tcp_unhash);
EXPORT_SYMBOL(tcp_v4_conn_request);
EXPORT_SYMBOL(tcp_v4_connect);
EXPORT_SYMBOL(tcp_v4_do_rcv);
EXPORT_SYMBOL(tcp_v4_remember_stamp);
EXPORT_SYMBOL(tcp_v4_send_check);
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);

#ifdef CONFIG_PROC_FS
EXPORT_SYMBOL(tcp_proc_register);
EXPORT_SYMBOL(tcp_proc_unregister);
#endif
EXPORT_SYMBOL(sysctl_local_port_range);
EXPORT_SYMBOL(sysctl_tcp_low_latency);