tcp_ipv4.c 63.0 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
/*
 * 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).
 *
 *		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
37
 *					request_sock handling and moved
L
Linus Torvalds 已提交
38 39
 *					most of it into the af independent code.
 *					Added tail drop and some other bugfixes.
S
Stephen Hemminger 已提交
40
 *					Added new listen semantics.
L
Linus Torvalds 已提交
41 42 43 44 45 46 47 48 49 50 51 52
 *		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.
 */

53
#define pr_fmt(fmt) "TCP: " fmt
L
Linus Torvalds 已提交
54

H
Herbert Xu 已提交
55
#include <linux/bottom_half.h>
L
Linus Torvalds 已提交
56 57 58 59 60 61 62 63
#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>
64
#include <linux/slab.h>
L
Linus Torvalds 已提交
65

66
#include <net/net_namespace.h>
L
Linus Torvalds 已提交
67
#include <net/icmp.h>
68
#include <net/inet_hashtables.h>
L
Linus Torvalds 已提交
69
#include <net/tcp.h>
70
#include <net/transp_v6.h>
L
Linus Torvalds 已提交
71 72
#include <net/ipv6.h>
#include <net/inet_common.h>
73
#include <net/timewait_sock.h>
L
Linus Torvalds 已提交
74
#include <net/xfrm.h>
75
#include <net/secure_seq.h>
G
Glauber Costa 已提交
76
#include <net/tcp_memcontrol.h>
77
#include <net/busy_poll.h>
L
Linus Torvalds 已提交
78 79 80 81 82 83 84

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

85 86 87
#include <linux/crypto.h>
#include <linux/scatterlist.h>

88 89
int sysctl_tcp_tw_reuse __read_mostly;
int sysctl_tcp_low_latency __read_mostly;
E
Eric Dumazet 已提交
90
EXPORT_SYMBOL(sysctl_tcp_low_latency);
L
Linus Torvalds 已提交
91

92
#ifdef CONFIG_TCP_MD5SIG
E
Eric Dumazet 已提交
93
static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
94
			       __be32 daddr, __be32 saddr, const struct tcphdr *th);
95 96
#endif

97
struct inet_hashinfo tcp_hashinfo;
E
Eric Dumazet 已提交
98
EXPORT_SYMBOL(tcp_hashinfo);
L
Linus Torvalds 已提交
99

100
static  __u32 tcp_v4_init_sequence(const struct sk_buff *skb)
L
Linus Torvalds 已提交
101
{
102 103
	return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
					  ip_hdr(skb)->saddr,
104 105
					  tcp_hdr(skb)->dest,
					  tcp_hdr(skb)->source);
L
Linus Torvalds 已提交
106 107
}

108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125
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 &&
126
			     get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
127 128 129 130 131 132 133 134 135 136 137 138 139
		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
140 141 142
/* This will initiate an outgoing connection. */
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
143
	struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
L
Linus Torvalds 已提交
144 145
	struct inet_sock *inet = inet_sk(sk);
	struct tcp_sock *tp = tcp_sk(sk);
146
	__be16 orig_sport, orig_dport;
147
	__be32 daddr, nexthop;
148
	struct flowi4 *fl4;
149
	struct rtable *rt;
L
Linus Torvalds 已提交
150
	int err;
151
	struct ip_options_rcu *inet_opt;
L
Linus Torvalds 已提交
152 153 154 155 156 157 158 159

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

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

	nexthop = daddr = usin->sin_addr.s_addr;
160 161 162
	inet_opt = rcu_dereference_protected(inet->inet_opt,
					     sock_owned_by_user(sk));
	if (inet_opt && inet_opt->opt.srr) {
L
Linus Torvalds 已提交
163 164
		if (!daddr)
			return -EINVAL;
165
		nexthop = inet_opt->opt.faddr;
L
Linus Torvalds 已提交
166 167
	}

168 169
	orig_sport = inet->inet_sport;
	orig_dport = usin->sin_port;
170 171
	fl4 = &inet->cork.fl.u.ip4;
	rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
172 173
			      RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
			      IPPROTO_TCP,
174
			      orig_sport, orig_dport, sk);
175 176 177
	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		if (err == -ENETUNREACH)
178
			IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
179
		return err;
180
	}
L
Linus Torvalds 已提交
181 182 183 184 185 186

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

187
	if (!inet_opt || !inet_opt->opt.srr)
188
		daddr = fl4->daddr;
L
Linus Torvalds 已提交
189

E
Eric Dumazet 已提交
190
	if (!inet->inet_saddr)
191
		inet->inet_saddr = fl4->saddr;
192
	sk_rcv_saddr_set(sk, inet->inet_saddr);
L
Linus Torvalds 已提交
193

E
Eric Dumazet 已提交
194
	if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
L
Linus Torvalds 已提交
195 196 197
		/* Reset inherited state */
		tp->rx_opt.ts_recent	   = 0;
		tp->rx_opt.ts_recent_stamp = 0;
P
Pavel Emelyanov 已提交
198 199
		if (likely(!tp->repair))
			tp->write_seq	   = 0;
L
Linus Torvalds 已提交
200 201
	}

202
	if (tcp_death_row.sysctl_tw_recycle &&
203 204
	    !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
		tcp_fetch_timewait_stamp(sk, &rt->dst);
L
Linus Torvalds 已提交
205

E
Eric Dumazet 已提交
206
	inet->inet_dport = usin->sin_port;
207
	sk_daddr_set(sk, daddr);
L
Linus Torvalds 已提交
208

209
	inet_csk(sk)->icsk_ext_hdr_len = 0;
210 211
	if (inet_opt)
		inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
L
Linus Torvalds 已提交
212

213
	tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
L
Linus Torvalds 已提交
214 215 216 217 218 219 220

	/* 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);
221
	err = inet_hash_connect(&tcp_death_row, sk);
L
Linus Torvalds 已提交
222 223 224
	if (err)
		goto failure;

225 226
	inet_set_txhash(sk);

227
	rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
228 229 230 231
			       inet->inet_sport, inet->inet_dport, sk);
	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		rt = NULL;
L
Linus Torvalds 已提交
232
		goto failure;
233
	}
L
Linus Torvalds 已提交
234
	/* OK, now commit destination to socket.  */
235
	sk->sk_gso_type = SKB_GSO_TCPV4;
236
	sk_setup_caps(sk, &rt->dst);
L
Linus Torvalds 已提交
237

P
Pavel Emelyanov 已提交
238
	if (!tp->write_seq && likely(!tp->repair))
E
Eric Dumazet 已提交
239 240 241
		tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
							   inet->inet_daddr,
							   inet->inet_sport,
L
Linus Torvalds 已提交
242 243
							   usin->sin_port);

E
Eric Dumazet 已提交
244
	inet->inet_id = tp->write_seq ^ jiffies;
L
Linus Torvalds 已提交
245

A
Andrey Vagin 已提交
246
	err = tcp_connect(sk);
P
Pavel Emelyanov 已提交
247

L
Linus Torvalds 已提交
248 249 250 251 252 253 254
	rt = NULL;
	if (err)
		goto failure;

	return 0;

failure:
255 256 257 258
	/*
	 * This unhashes the socket and releases the local port,
	 * if necessary.
	 */
L
Linus Torvalds 已提交
259 260 261
	tcp_set_state(sk, TCP_CLOSE);
	ip_rt_put(rt);
	sk->sk_route_caps = 0;
E
Eric Dumazet 已提交
262
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
263 264
	return err;
}
E
Eric Dumazet 已提交
265
EXPORT_SYMBOL(tcp_v4_connect);
L
Linus Torvalds 已提交
266 267

/*
268 269 270
 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
 * It can be called through tcp_release_cb() if socket was owned by user
 * at the time tcp_v4_err() was called to handle ICMP message.
L
Linus Torvalds 已提交
271
 */
272
void tcp_v4_mtu_reduced(struct sock *sk)
L
Linus Torvalds 已提交
273 274 275
{
	struct dst_entry *dst;
	struct inet_sock *inet = inet_sk(sk);
276
	u32 mtu = tcp_sk(sk)->mtu_info;
L
Linus Torvalds 已提交
277

278 279
	dst = inet_csk_update_pmtu(sk, mtu);
	if (!dst)
L
Linus Torvalds 已提交
280 281 282 283 284 285 286 287 288 289 290
		return;

	/* 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 &&
291
	    ip_sk_accept_pmtu(sk) &&
292
	    inet_csk(sk)->icsk_pmtu_cookie > mtu) {
L
Linus Torvalds 已提交
293 294 295 296 297 298 299 300 301 302
		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 */
}
303
EXPORT_SYMBOL(tcp_v4_mtu_reduced);
L
Linus Torvalds 已提交
304

305 306 307 308
static void do_redirect(struct sk_buff *skb, struct sock *sk)
{
	struct dst_entry *dst = __sk_dst_check(sk, 0);

309
	if (dst)
310
		dst->ops->redirect(dst, sk, skb);
311 312
}

313 314 315 316 317 318 319 320 321 322 323 324 325 326

/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
void tcp_req_err(struct sock *sk, u32 seq)
{
	struct request_sock *req = inet_reqsk(sk);
	struct net *net = sock_net(sk);

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

	if (seq != tcp_rsk(req)->snt_isn) {
		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
F
Fan Du 已提交
327
		reqsk_put(req);
328 329 330 331 332 333 334 335
	} else {
		/*
		 * 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().
		 */
		NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
F
Fan Du 已提交
336
		inet_csk_reqsk_queue_drop(req->rsk_listener, req);
337 338 339 340
	}
}
EXPORT_SYMBOL(tcp_req_err);

L
Linus Torvalds 已提交
341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356
/*
 * 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.
 *
 */

357
void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
L
Linus Torvalds 已提交
358
{
359
	const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
360
	struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
361
	struct inet_connection_sock *icsk;
L
Linus Torvalds 已提交
362 363
	struct tcp_sock *tp;
	struct inet_sock *inet;
364 365
	const int type = icmp_hdr(icmp_skb)->type;
	const int code = icmp_hdr(icmp_skb)->code;
L
Linus Torvalds 已提交
366
	struct sock *sk;
367
	struct sk_buff *skb;
368 369
	struct request_sock *fastopen;
	__u32 seq, snd_una;
370
	__u32 remaining;
L
Linus Torvalds 已提交
371
	int err;
372
	struct net *net = dev_net(icmp_skb->dev);
L
Linus Torvalds 已提交
373

374 375 376
	sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
				       th->dest, iph->saddr, ntohs(th->source),
				       inet_iif(icmp_skb));
L
Linus Torvalds 已提交
377
	if (!sk) {
378
		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
L
Linus Torvalds 已提交
379 380 381
		return;
	}
	if (sk->sk_state == TCP_TIME_WAIT) {
382
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
383 384
		return;
	}
385 386 387
	seq = ntohl(th->seq);
	if (sk->sk_state == TCP_NEW_SYN_RECV)
		return tcp_req_err(sk, seq);
L
Linus Torvalds 已提交
388 389 390 391

	bh_lock_sock(sk);
	/* If too many ICMPs get dropped on busy
	 * servers this needs to be solved differently.
392 393
	 * We do take care of PMTU discovery (RFC1191) special case :
	 * we can receive locally generated ICMP messages while socket is held.
L
Linus Torvalds 已提交
394
	 */
395 396 397 398
	if (sock_owned_by_user(sk)) {
		if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
			NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
	}
L
Linus Torvalds 已提交
399 400 401
	if (sk->sk_state == TCP_CLOSE)
		goto out;

402 403 404 405 406
	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
		goto out;
	}

407
	icsk = inet_csk(sk);
L
Linus Torvalds 已提交
408
	tp = tcp_sk(sk);
409 410 411
	/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
	fastopen = tp->fastopen_rsk;
	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
L
Linus Torvalds 已提交
412
	if (sk->sk_state != TCP_LISTEN &&
413
	    !between(seq, snd_una, tp->snd_nxt)) {
414
		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
L
Linus Torvalds 已提交
415 416 417 418
		goto out;
	}

	switch (type) {
419 420 421
	case ICMP_REDIRECT:
		do_redirect(icmp_skb, sk);
		goto out;
L
Linus Torvalds 已提交
422 423 424 425 426 427 428 429 430 431 432
	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) */
433 434 435 436 437 438 439
			/* 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)
				goto out;

440
			tp->mtu_info = info;
441
			if (!sock_owned_by_user(sk)) {
442
				tcp_v4_mtu_reduced(sk);
443 444 445 446
			} else {
				if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
					sock_hold(sk);
			}
L
Linus Torvalds 已提交
447 448 449 450
			goto out;
		}

		err = icmp_err_convert[code].errno;
451 452 453 454 455
		/* check if icmp_skb allows revert of backoff
		 * (see draft-zimmermann-tcp-lcd) */
		if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
			break;
		if (seq != tp->snd_una  || !icsk->icsk_retransmits ||
456
		    !icsk->icsk_backoff || fastopen)
457 458
			break;

459 460 461
		if (sock_owned_by_user(sk))
			break;

462
		icsk->icsk_backoff--;
463 464 465
		icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
					       TCP_TIMEOUT_INIT;
		icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
466 467 468 469

		skb = tcp_write_queue_head(sk);
		BUG_ON(!skb);

E
Eric Dumazet 已提交
470 471 472
		remaining = icsk->icsk_rto -
			    min(icsk->icsk_rto,
				tcp_time_stamp - tcp_skb_timestamp(skb));
473 474 475 476 477 478 479 480 481 482

		if (remaining) {
			inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
						  remaining, TCP_RTO_MAX);
		} else {
			/* RTO revert clocked out retransmission.
			 * Will retransmit now */
			tcp_retransmit_timer(sk);
		}

L
Linus Torvalds 已提交
483 484 485 486 487 488 489 490 491 492
		break;
	case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;
		break;
	default:
		goto out;
	}

	switch (sk->sk_state) {
	case TCP_SYN_SENT:
493 494 495 496 497 498 499
	case TCP_SYN_RECV:
		/* Only in fast or simultaneous open. If a fast open socket is
		 * is already accepted it is treated as a connected one below.
		 */
		if (fastopen && fastopen->sk == NULL)
			break;

L
Linus Torvalds 已提交
500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540
		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);
}

541
void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
L
Linus Torvalds 已提交
542
{
543
	struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
544

545
	if (skb->ip_summed == CHECKSUM_PARTIAL) {
546
		th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
547
		skb->csum_start = skb_transport_header(skb) - skb->head;
A
Al Viro 已提交
548
		skb->csum_offset = offsetof(struct tcphdr, check);
L
Linus Torvalds 已提交
549
	} else {
550
		th->check = tcp_v4_check(skb->len, saddr, daddr,
551
					 csum_partial(th,
L
Linus Torvalds 已提交
552 553 554 555 556
						      th->doff << 2,
						      skb->csum));
	}
}

557
/* This routine computes an IPv4 TCP checksum. */
558
void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
559
{
560
	const struct inet_sock *inet = inet_sk(sk);
561 562 563

	__tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
}
E
Eric Dumazet 已提交
564
EXPORT_SYMBOL(tcp_v4_send_check);
565

L
Linus Torvalds 已提交
566 567 568 569 570 571 572 573 574 575 576 577 578
/*
 *	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.
 */

579
static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
580
{
581
	const struct tcphdr *th = tcp_hdr(skb);
582 583 584
	struct {
		struct tcphdr th;
#ifdef CONFIG_TCP_MD5SIG
585
		__be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
586 587
#endif
	} rep;
L
Linus Torvalds 已提交
588
	struct ip_reply_arg arg;
589 590
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
591 592 593 594
	const __u8 *hash_location = NULL;
	unsigned char newhash[16];
	int genhash;
	struct sock *sk1 = NULL;
595
#endif
596
	struct net *net;
L
Linus Torvalds 已提交
597 598 599 600 601

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

602 603 604 605
	/* If sk not NULL, it means we did a successful lookup and incoming
	 * route had to be correct. prequeue might have dropped our dst.
	 */
	if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
L
Linus Torvalds 已提交
606 607 608
		return;

	/* Swap the send and the receive. */
609 610 611 612 613
	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
614 615

	if (th->ack) {
616
		rep.th.seq = th->ack_seq;
L
Linus Torvalds 已提交
617
	} else {
618 619 620
		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
621 622
	}

623
	memset(&arg, 0, sizeof(arg));
624 625 626
	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);

627
	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
628
#ifdef CONFIG_TCP_MD5SIG
629 630 631 632 633 634 635 636 637
	hash_location = tcp_parse_md5sig_option(th);
	if (!sk && hash_location) {
		/*
		 * active side is lost. Try to find listening socket through
		 * source port, and then find md5 key through listening socket.
		 * we are not loose security here:
		 * Incoming packet is checked with md5 hash with finding key,
		 * no RST generated if md5 hash doesn't match.
		 */
638
		sk1 = __inet_lookup_listener(net,
639 640
					     &tcp_hashinfo, ip_hdr(skb)->saddr,
					     th->source, ip_hdr(skb)->daddr,
641 642 643 644 645 646 647 648 649 650
					     ntohs(th->source), inet_iif(skb));
		/* don't send rst if it can't find key */
		if (!sk1)
			return;
		rcu_read_lock();
		key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
					&ip_hdr(skb)->saddr, AF_INET);
		if (!key)
			goto release_sk1;

651
		genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
652 653 654 655 656 657 658 659
		if (genhash || memcmp(hash_location, newhash, 16) != 0)
			goto release_sk1;
	} else {
		key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
					     &ip_hdr(skb)->saddr,
					     AF_INET) : NULL;
	}

660 661 662 663 664 665 666 667 668
	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;

669
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
670 671
				     key, ip_hdr(skb)->saddr,
				     ip_hdr(skb)->daddr, &rep.th);
672 673
	}
#endif
674 675
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
676
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
L
Linus Torvalds 已提交
677
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
678
	arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
679
	/* When socket is gone, all binding information is lost.
A
Alexey Kuznetsov 已提交
680 681
	 * routing might fail in this case. No choice here, if we choose to force
	 * input interface, we will misroute in case of asymmetric route.
682
	 */
A
Alexey Kuznetsov 已提交
683 684
	if (sk)
		arg.bound_dev_if = sk->sk_bound_dev_if;
L
Linus Torvalds 已提交
685

686
	arg.tos = ip_hdr(skb)->tos;
687 688
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
689 690
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
691

692 693
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
	TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
694 695 696 697 698 699 700 701

#ifdef CONFIG_TCP_MD5SIG
release_sk1:
	if (sk1) {
		rcu_read_unlock();
		sock_put(sk1);
	}
#endif
L
Linus Torvalds 已提交
702 703 704 705 706 707
}

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

708
static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
709
			    u32 win, u32 tsval, u32 tsecr, int oif,
710
			    struct tcp_md5sig_key *key,
711
			    int reply_flags, u8 tos)
L
Linus Torvalds 已提交
712
{
713
	const struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
714 715
	struct {
		struct tcphdr th;
716
		__be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
717
#ifdef CONFIG_TCP_MD5SIG
718
			   + (TCPOLEN_MD5SIG_ALIGNED >> 2)
719 720
#endif
			];
L
Linus Torvalds 已提交
721 722
	} rep;
	struct ip_reply_arg arg;
E
Eric Dumazet 已提交
723
	struct net *net = dev_net(skb_dst(skb)->dev);
L
Linus Torvalds 已提交
724 725

	memset(&rep.th, 0, sizeof(struct tcphdr));
726
	memset(&arg, 0, sizeof(arg));
L
Linus Torvalds 已提交
727 728 729

	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);
730
	if (tsecr) {
731 732 733
		rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
				   (TCPOPT_TIMESTAMP << 8) |
				   TCPOLEN_TIMESTAMP);
734 735
		rep.opt[1] = htonl(tsval);
		rep.opt[2] = htonl(tsecr);
736
		arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
L
Linus Torvalds 已提交
737 738 739 740 741 742 743 744 745 746 747
	}

	/* 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);

748 749
#ifdef CONFIG_TCP_MD5SIG
	if (key) {
750
		int offset = (tsecr) ? 3 : 0;
751 752 753 754 755 756 757 758

		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;

759
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
760 761
				    key, ip_hdr(skb)->saddr,
				    ip_hdr(skb)->daddr, &rep.th);
762 763
	}
#endif
764
	arg.flags = reply_flags;
765 766
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
L
Linus Torvalds 已提交
767 768
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
769 770
	if (oif)
		arg.bound_dev_if = oif;
771
	arg.tos = tos;
772 773
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
774 775
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
776

777
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
L
Linus Torvalds 已提交
778 779 780 781
}

static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
782
	struct inet_timewait_sock *tw = inet_twsk(sk);
783
	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
784

785
	tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
786
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
787
			tcp_time_stamp + tcptw->tw_ts_offset,
788 789
			tcptw->tw_ts_recent,
			tw->tw_bound_dev_if,
790
			tcp_twsk_md5_key(tcptw),
791 792
			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
			tw->tw_tos
793
			);
L
Linus Torvalds 已提交
794

795
	inet_twsk_put(tw);
L
Linus Torvalds 已提交
796 797
}

798
static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
799
				  struct request_sock *req)
L
Linus Torvalds 已提交
800
{
801 802 803 804 805 806
	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
	 */
	tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
			tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
807
			tcp_time_stamp,
808 809
			req->ts_recent,
			0,
E
Eric Dumazet 已提交
810 811
			tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
					  AF_INET),
812 813
			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
			ip_hdr(skb)->tos);
L
Linus Torvalds 已提交
814 815 816
}

/*
817
 *	Send a SYN-ACK after having received a SYN.
818
 *	This still operates on a request_sock only, not on a big
L
Linus Torvalds 已提交
819 820
 *	socket.
 */
821
static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
822
			      struct flowi *fl,
823
			      struct request_sock *req,
824 825
			      u16 queue_mapping,
			      struct tcp_fastopen_cookie *foc)
L
Linus Torvalds 已提交
826
{
827
	const struct inet_request_sock *ireq = inet_rsk(req);
828
	struct flowi4 fl4;
L
Linus Torvalds 已提交
829
	int err = -1;
830
	struct sk_buff *skb;
L
Linus Torvalds 已提交
831 832

	/* First, grab a route. */
833
	if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
834
		return -1;
L
Linus Torvalds 已提交
835

836
	skb = tcp_make_synack(sk, dst, req, foc);
L
Linus Torvalds 已提交
837 838

	if (skb) {
839
		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
L
Linus Torvalds 已提交
840

841
		skb_set_queue_mapping(skb, queue_mapping);
842 843
		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
					    ireq->ir_rmt_addr,
844
					    ireq->opt);
845
		err = net_xmit_eval(err);
L
Linus Torvalds 已提交
846 847 848 849 850 851
	}

	return err;
}

/*
852
 *	IPv4 request_sock destructor.
L
Linus Torvalds 已提交
853
 */
854
static void tcp_v4_reqsk_destructor(struct request_sock *req)
L
Linus Torvalds 已提交
855
{
J
Jesper Juhl 已提交
856
	kfree(inet_rsk(req)->opt);
L
Linus Torvalds 已提交
857 858
}

859
/*
E
Eric Dumazet 已提交
860
 * Return true if a syncookie should be sent
861
 */
E
Eric Dumazet 已提交
862
bool tcp_syn_flood_action(struct sock *sk,
863 864
			 const struct sk_buff *skb,
			 const char *proto)
L
Linus Torvalds 已提交
865
{
866
	const char *msg = "Dropping request";
E
Eric Dumazet 已提交
867
	bool want_cookie = false;
868 869
	struct listen_sock *lopt;

870
#ifdef CONFIG_SYN_COOKIES
871
	if (sysctl_tcp_syncookies) {
872
		msg = "Sending cookies";
E
Eric Dumazet 已提交
873
		want_cookie = true;
874 875
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
	} else
876
#endif
877 878 879
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);

	lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
880
	if (!lopt->synflood_warned && sysctl_tcp_syncookies != 2) {
881
		lopt->synflood_warned = 1;
882
		pr_info("%s: Possible SYN flooding on port %d. %s.  Check SNMP counters.\n",
883 884 885
			proto, ntohs(tcp_hdr(skb)->dest), msg);
	}
	return want_cookie;
886
}
887
EXPORT_SYMBOL(tcp_syn_flood_action);
L
Linus Torvalds 已提交
888

889 890 891 892 893 894 895 896
#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.  */
E
Eric Dumazet 已提交
897 898 899
struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
					 const union tcp_md5_addr *addr,
					 int family)
900 901
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
902 903
	struct tcp_md5sig_key *key;
	unsigned int size = sizeof(struct in_addr);
904
	struct tcp_md5sig_info *md5sig;
905

906 907
	/* caller either holds rcu_read_lock() or socket lock */
	md5sig = rcu_dereference_check(tp->md5sig_info,
908 909
				       sock_owned_by_user(sk) ||
				       lockdep_is_held(&sk->sk_lock.slock));
910
	if (!md5sig)
911
		return NULL;
E
Eric Dumazet 已提交
912 913 914 915
#if IS_ENABLED(CONFIG_IPV6)
	if (family == AF_INET6)
		size = sizeof(struct in6_addr);
#endif
916
	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
E
Eric Dumazet 已提交
917 918 919 920
		if (key->family != family)
			continue;
		if (!memcmp(&key->addr, addr, size))
			return key;
921 922 923
	}
	return NULL;
}
E
Eric Dumazet 已提交
924
EXPORT_SYMBOL(tcp_md5_do_lookup);
925 926 927 928

struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
					 struct sock *addr_sk)
{
E
Eric Dumazet 已提交
929 930 931 932
	union tcp_md5_addr *addr;

	addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr;
	return tcp_md5_do_lookup(sk, addr, AF_INET);
933 934 935
}
EXPORT_SYMBOL(tcp_v4_md5_lookup);

A
Adrian Bunk 已提交
936 937
static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
						      struct request_sock *req)
938
{
E
Eric Dumazet 已提交
939 940
	union tcp_md5_addr *addr;

941
	addr = (union tcp_md5_addr *)&inet_rsk(req)->ir_rmt_addr;
E
Eric Dumazet 已提交
942
	return tcp_md5_do_lookup(sk, addr, AF_INET);
943 944 945
}

/* This can be called on a newly created socket, from other files */
E
Eric Dumazet 已提交
946 947
int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
		   int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
948 949
{
	/* Add Key to the list */
950
	struct tcp_md5sig_key *key;
951
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
952
	struct tcp_md5sig_info *md5sig;
953

954
	key = tcp_md5_do_lookup(sk, addr, family);
955 956
	if (key) {
		/* Pre-existing entry - just update that one. */
E
Eric Dumazet 已提交
957
		memcpy(key->key, newkey, newkeylen);
958
		key->keylen = newkeylen;
E
Eric Dumazet 已提交
959 960
		return 0;
	}
961

962 963
	md5sig = rcu_dereference_protected(tp->md5sig_info,
					   sock_owned_by_user(sk));
E
Eric Dumazet 已提交
964 965 966
	if (!md5sig) {
		md5sig = kmalloc(sizeof(*md5sig), gfp);
		if (!md5sig)
967 968
			return -ENOMEM;

E
Eric Dumazet 已提交
969 970
		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
		INIT_HLIST_HEAD(&md5sig->head);
971
		rcu_assign_pointer(tp->md5sig_info, md5sig);
E
Eric Dumazet 已提交
972
	}
973

974
	key = sock_kmalloc(sk, sizeof(*key), gfp);
E
Eric Dumazet 已提交
975 976
	if (!key)
		return -ENOMEM;
977
	if (!tcp_alloc_md5sig_pool()) {
978
		sock_kfree_s(sk, key, sizeof(*key));
E
Eric Dumazet 已提交
979
		return -ENOMEM;
980
	}
E
Eric Dumazet 已提交
981 982 983 984 985 986 987 988

	memcpy(key->key, newkey, newkeylen);
	key->keylen = newkeylen;
	key->family = family;
	memcpy(&key->addr, addr,
	       (family == AF_INET6) ? sizeof(struct in6_addr) :
				      sizeof(struct in_addr));
	hlist_add_head_rcu(&key->node, &md5sig->head);
989 990
	return 0;
}
E
Eric Dumazet 已提交
991
EXPORT_SYMBOL(tcp_md5_do_add);
992

E
Eric Dumazet 已提交
993
int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
994
{
E
Eric Dumazet 已提交
995 996
	struct tcp_md5sig_key *key;

997
	key = tcp_md5_do_lookup(sk, addr, family);
E
Eric Dumazet 已提交
998 999 1000
	if (!key)
		return -ENOENT;
	hlist_del_rcu(&key->node);
1001
	atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
1002 1003
	kfree_rcu(key, rcu);
	return 0;
1004
}
E
Eric Dumazet 已提交
1005
EXPORT_SYMBOL(tcp_md5_do_del);
1006

1007
static void tcp_clear_md5_list(struct sock *sk)
1008 1009
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1010
	struct tcp_md5sig_key *key;
1011
	struct hlist_node *n;
1012
	struct tcp_md5sig_info *md5sig;
1013

1014 1015
	md5sig = rcu_dereference_protected(tp->md5sig_info, 1);

1016
	hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
E
Eric Dumazet 已提交
1017
		hlist_del_rcu(&key->node);
1018
		atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
1019
		kfree_rcu(key, rcu);
1020 1021 1022
	}
}

1023 1024
static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
				 int optlen)
1025 1026 1027 1028 1029 1030 1031
{
	struct tcp_md5sig cmd;
	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;

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

1032
	if (copy_from_user(&cmd, optval, sizeof(cmd)))
1033 1034 1035 1036 1037
		return -EFAULT;

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

1038
	if (!cmd.tcpm_keylen)
E
Eric Dumazet 已提交
1039 1040
		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
				      AF_INET);
1041 1042 1043 1044

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

E
Eric Dumazet 已提交
1045 1046 1047
	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
			      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
			      GFP_KERNEL);
1048 1049
}

1050 1051
static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
					__be32 daddr, __be32 saddr, int nbytes)
1052 1053
{
	struct tcp4_pseudohdr *bp;
1054
	struct scatterlist sg;
1055 1056 1057 1058

	bp = &hp->md5_blk.ip4;

	/*
1059
	 * 1. the TCP pseudo-header (in the order: source IP address,
1060 1061 1062 1063 1064 1065
	 * destination IP address, zero-padded protocol number, and
	 * segment length)
	 */
	bp->saddr = saddr;
	bp->daddr = daddr;
	bp->pad = 0;
1066
	bp->protocol = IPPROTO_TCP;
1067
	bp->len = cpu_to_be16(nbytes);
1068

1069 1070 1071 1072
	sg_init_one(&sg, bp, sizeof(*bp));
	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
}

E
Eric Dumazet 已提交
1073
static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
1074
			       __be32 daddr, __be32 saddr, const struct tcphdr *th)
1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092
{
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;

	hp = tcp_get_md5sig_pool();
	if (!hp)
		goto clear_hash_noput;
	desc = &hp->md5_desc;

	if (crypto_hash_init(desc))
		goto clear_hash;
	if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
		goto clear_hash;
	if (tcp_md5_hash_header(hp, th))
		goto clear_hash;
	if (tcp_md5_hash_key(hp, key))
		goto clear_hash;
	if (crypto_hash_final(desc, md5_hash))
1093 1094 1095 1096
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;
1097

1098 1099 1100 1101
clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
1102
	return 1;
1103 1104
}

1105 1106
int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
			const struct sock *sk,
E
Eric Dumazet 已提交
1107
			const struct sk_buff *skb)
1108
{
1109 1110
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
E
Eric Dumazet 已提交
1111
	const struct tcphdr *th = tcp_hdr(skb);
1112 1113
	__be32 saddr, daddr;

1114 1115 1116
	if (sk) { /* valid for establish/request sockets */
		saddr = sk->sk_rcv_saddr;
		daddr = sk->sk_daddr;
1117
	} else {
1118 1119 1120
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
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

	hp = tcp_get_md5sig_pool();
	if (!hp)
		goto clear_hash_noput;
	desc = &hp->md5_desc;

	if (crypto_hash_init(desc))
		goto clear_hash;

	if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
		goto clear_hash;
	if (tcp_md5_hash_header(hp, th))
		goto clear_hash;
	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
		goto clear_hash;
	if (tcp_md5_hash_key(hp, key))
		goto clear_hash;
	if (crypto_hash_final(desc, md5_hash))
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;

clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
	return 1;
1150
}
1151
EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1152

1153 1154 1155
/* Called with rcu_read_lock() */
static bool tcp_v4_inbound_md5_hash(struct sock *sk,
				    const struct sk_buff *skb)
1156 1157 1158 1159 1160 1161 1162 1163 1164
{
	/*
	 * 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.
	 */
1165
	const __u8 *hash_location = NULL;
1166
	struct tcp_md5sig_key *hash_expected;
1167
	const struct iphdr *iph = ip_hdr(skb);
1168
	const struct tcphdr *th = tcp_hdr(skb);
1169 1170 1171
	int genhash;
	unsigned char newhash[16];

E
Eric Dumazet 已提交
1172 1173
	hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
					  AF_INET);
1174
	hash_location = tcp_parse_md5sig_option(th);
1175 1176 1177

	/* We've parsed the options - do we have a hash? */
	if (!hash_expected && !hash_location)
E
Eric Dumazet 已提交
1178
		return false;
1179 1180

	if (hash_expected && !hash_location) {
1181
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
E
Eric Dumazet 已提交
1182
		return true;
1183 1184 1185
	}

	if (!hash_expected && hash_location) {
1186
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
E
Eric Dumazet 已提交
1187
		return true;
1188 1189 1190 1191 1192
	}

	/* Okay, so this is hash_expected and hash_location -
	 * so we need to calculate the checksum.
	 */
1193 1194
	genhash = tcp_v4_md5_hash_skb(newhash,
				      hash_expected,
1195
				      NULL, skb);
1196 1197

	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1198 1199 1200 1201 1202
		net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
				     &iph->saddr, ntohs(th->source),
				     &iph->daddr, ntohs(th->dest),
				     genhash ? " tcp_v4_calc_md5_hash failed"
				     : "");
E
Eric Dumazet 已提交
1203
		return true;
1204
	}
E
Eric Dumazet 已提交
1205
	return false;
1206 1207 1208
}
#endif

1209
static void tcp_v4_init_req(struct request_sock *req, struct sock *sk_listener,
1210 1211 1212 1213
			    struct sk_buff *skb)
{
	struct inet_request_sock *ireq = inet_rsk(req);

1214 1215 1216
	sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
	sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
	ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1217
	ireq->opt = tcp_v4_save_options(skb);
E
Eric Dumazet 已提交
1218
	ireq->ireq_family = AF_INET;
1219 1220
}

1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236
static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl,
					  const struct request_sock *req,
					  bool *strict)
{
	struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);

	if (strict) {
		if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
			*strict = true;
		else
			*strict = false;
	}

	return dst;
}

1237
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
L
Linus Torvalds 已提交
1238
	.family		=	PF_INET,
1239
	.obj_size	=	sizeof(struct tcp_request_sock),
1240
	.rtx_syn_ack	=	tcp_rtx_synack,
1241 1242
	.send_ack	=	tcp_v4_reqsk_send_ack,
	.destructor	=	tcp_v4_reqsk_destructor,
L
Linus Torvalds 已提交
1243
	.send_reset	=	tcp_v4_send_reset,
S
stephen hemminger 已提交
1244
	.syn_ack_timeout =	tcp_syn_ack_timeout,
L
Linus Torvalds 已提交
1245 1246
};

1247
static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1248
	.mss_clamp	=	TCP_MSS_DEFAULT,
1249
#ifdef CONFIG_TCP_MD5SIG
1250
	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
1251
	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1252
#endif
1253
	.init_req	=	tcp_v4_init_req,
1254 1255 1256
#ifdef CONFIG_SYN_COOKIES
	.cookie_init_seq =	cookie_v4_init_sequence,
#endif
1257
	.route_req	=	tcp_v4_route_req,
1258
	.init_seq	=	tcp_v4_init_sequence,
1259
	.send_synack	=	tcp_v4_send_synack,
1260
	.queue_hash_add =	inet_csk_reqsk_queue_hash_add,
1261
};
1262

L
Linus Torvalds 已提交
1263 1264 1265
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
	/* Never answer to SYNs send to broadcast or multicast */
E
Eric Dumazet 已提交
1266
	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
L
Linus Torvalds 已提交
1267 1268
		goto drop;

O
Octavian Purdila 已提交
1269 1270
	return tcp_conn_request(&tcp_request_sock_ops,
				&tcp_request_sock_ipv4_ops, sk, skb);
L
Linus Torvalds 已提交
1271 1272

drop:
1273
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1274 1275
	return 0;
}
E
Eric Dumazet 已提交
1276
EXPORT_SYMBOL(tcp_v4_conn_request);
L
Linus Torvalds 已提交
1277 1278 1279 1280 1281 1282 1283


/*
 * 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,
1284
				  struct request_sock *req,
L
Linus Torvalds 已提交
1285 1286
				  struct dst_entry *dst)
{
1287
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1288 1289 1290
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
1291 1292 1293
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
1294
	struct ip_options_rcu *inet_opt;
L
Linus Torvalds 已提交
1295 1296 1297 1298 1299 1300

	if (sk_acceptq_is_full(sk))
		goto exit_overflow;

	newsk = tcp_create_openreq_child(sk, req, skb);
	if (!newsk)
1301
		goto exit_nonewsk;
L
Linus Torvalds 已提交
1302

1303
	newsk->sk_gso_type = SKB_GSO_TCPV4;
1304
	inet_sk_rx_dst_set(newsk, skb);
L
Linus Torvalds 已提交
1305 1306 1307

	newtp		      = tcp_sk(newsk);
	newinet		      = inet_sk(newsk);
1308
	ireq		      = inet_rsk(req);
1309 1310
	sk_daddr_set(newsk, ireq->ir_rmt_addr);
	sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1311
	newinet->inet_saddr	      = ireq->ir_loc_addr;
1312 1313
	inet_opt	      = ireq->opt;
	rcu_assign_pointer(newinet->inet_opt, inet_opt);
1314
	ireq->opt	      = NULL;
1315
	newinet->mc_index     = inet_iif(skb);
1316
	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
1317
	newinet->rcv_tos      = ip_hdr(skb)->tos;
1318
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1319
	inet_set_txhash(newsk);
1320 1321
	if (inet_opt)
		inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
E
Eric Dumazet 已提交
1322
	newinet->inet_id = newtp->write_seq ^ jiffies;
L
Linus Torvalds 已提交
1323

E
Eric Dumazet 已提交
1324 1325 1326 1327 1328 1329 1330
	if (!dst) {
		dst = inet_csk_route_child_sock(sk, newsk, req);
		if (!dst)
			goto put_and_exit;
	} else {
		/* syncookie case : see end of cookie_v4_check() */
	}
1331 1332
	sk_setup_caps(newsk, dst);

1333 1334
	tcp_ca_openreq_child(newsk, dst);

L
Linus Torvalds 已提交
1335
	tcp_sync_mss(newsk, dst_mtu(dst));
1336
	newtp->advmss = dst_metric_advmss(dst);
1337 1338 1339 1340
	if (tcp_sk(sk)->rx_opt.user_mss &&
	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;

L
Linus Torvalds 已提交
1341 1342
	tcp_initialize_rcv_mss(newsk);

1343 1344
#ifdef CONFIG_TCP_MD5SIG
	/* Copy over the MD5 key from the original socket */
E
Eric Dumazet 已提交
1345 1346
	key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
				AF_INET);
E
Eric Dumazet 已提交
1347
	if (key != NULL) {
1348 1349 1350 1351 1352 1353
		/*
		 * 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.
		 */
E
Eric Dumazet 已提交
1354 1355
		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
			       AF_INET, key->key, key->keylen, GFP_ATOMIC);
E
Eric Dumazet 已提交
1356
		sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1357 1358 1359
	}
#endif

1360 1361
	if (__inet_inherit_port(sk, newsk) < 0)
		goto put_and_exit;
1362
	__inet_hash_nolisten(newsk, NULL);
L
Linus Torvalds 已提交
1363 1364 1365 1366

	return newsk;

exit_overflow:
1367
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1368 1369
exit_nonewsk:
	dst_release(dst);
L
Linus Torvalds 已提交
1370
exit:
1371
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1372
	return NULL;
1373
put_and_exit:
1374 1375
	inet_csk_prepare_forced_close(newsk);
	tcp_done(newsk);
1376
	goto exit;
L
Linus Torvalds 已提交
1377
}
E
Eric Dumazet 已提交
1378
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
L
Linus Torvalds 已提交
1379 1380 1381

static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
{
1382
	const struct tcphdr *th = tcp_hdr(skb);
1383
	const struct iphdr *iph = ip_hdr(skb);
1384
	struct request_sock *req;
L
Linus Torvalds 已提交
1385
	struct sock *nsk;
1386 1387

	req = inet_csk_search_req(sk, th->source, iph->saddr, iph->daddr);
1388 1389 1390 1391 1392
	if (req) {
		nsk = tcp_check_req(sk, skb, req, false);
		reqsk_put(req);
		return nsk;
	}
L
Linus Torvalds 已提交
1393

1394
	nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1395
			th->source, iph->daddr, th->dest, inet_iif(skb));
L
Linus Torvalds 已提交
1396 1397 1398 1399 1400 1401

	if (nsk) {
		if (nsk->sk_state != TCP_TIME_WAIT) {
			bh_lock_sock(nsk);
			return nsk;
		}
1402
		inet_twsk_put(inet_twsk(nsk));
L
Linus Torvalds 已提交
1403 1404 1405 1406
		return NULL;
	}

#ifdef CONFIG_SYN_COOKIES
1407
	if (!th->syn)
C
Cong Wang 已提交
1408
		sk = cookie_v4_check(sk, skb);
L
Linus Torvalds 已提交
1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422
#endif
	return sk;
}

/* 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)
{
1423 1424
	struct sock *rsk;

L
Linus Torvalds 已提交
1425
	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1426 1427
		struct dst_entry *dst = sk->sk_rx_dst;

1428
		sock_rps_save_rxhash(sk, skb);
1429
		sk_mark_napi_id(sk, skb);
1430
		if (dst) {
E
Eric Dumazet 已提交
1431 1432
			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
			    dst->ops->check(dst, 0) == NULL) {
1433 1434 1435 1436
				dst_release(dst);
				sk->sk_rx_dst = NULL;
			}
		}
1437
		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
L
Linus Torvalds 已提交
1438 1439 1440
		return 0;
	}

1441
	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
L
Linus Torvalds 已提交
1442 1443 1444 1445 1446 1447 1448 1449
		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) {
1450
			sock_rps_save_rxhash(nsk, skb);
1451
			sk_mark_napi_id(sk, skb);
1452 1453
			if (tcp_child_process(sk, nsk, skb)) {
				rsk = nsk;
L
Linus Torvalds 已提交
1454
				goto reset;
1455
			}
L
Linus Torvalds 已提交
1456 1457
			return 0;
		}
1458
	} else
1459
		sock_rps_save_rxhash(sk, skb);
1460

1461
	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1462
		rsk = sk;
L
Linus Torvalds 已提交
1463
		goto reset;
1464
	}
L
Linus Torvalds 已提交
1465 1466 1467
	return 0;

reset:
1468
	tcp_v4_send_reset(rsk, skb);
L
Linus Torvalds 已提交
1469 1470 1471 1472 1473 1474 1475 1476 1477 1478
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:
1479
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1480
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1481 1482
	goto discard;
}
E
Eric Dumazet 已提交
1483
EXPORT_SYMBOL(tcp_v4_do_rcv);
L
Linus Torvalds 已提交
1484

1485
void tcp_v4_early_demux(struct sk_buff *skb)
D
David S. Miller 已提交
1486 1487 1488 1489 1490 1491
{
	const struct iphdr *iph;
	const struct tcphdr *th;
	struct sock *sk;

	if (skb->pkt_type != PACKET_HOST)
1492
		return;
D
David S. Miller 已提交
1493

1494
	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1495
		return;
D
David S. Miller 已提交
1496 1497

	iph = ip_hdr(skb);
1498
	th = tcp_hdr(skb);
D
David S. Miller 已提交
1499 1500

	if (th->doff < sizeof(struct tcphdr) / 4)
1501
		return;
D
David S. Miller 已提交
1502

1503
	sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
D
David S. Miller 已提交
1504
				       iph->saddr, th->source,
1505
				       iph->daddr, ntohs(th->dest),
E
Eric Dumazet 已提交
1506
				       skb->skb_iif);
D
David S. Miller 已提交
1507 1508 1509
	if (sk) {
		skb->sk = sk;
		skb->destructor = sock_edemux;
1510
		if (sk_fullsock(sk)) {
D
David S. Miller 已提交
1511
			struct dst_entry *dst = sk->sk_rx_dst;
E
Eric Dumazet 已提交
1512

D
David S. Miller 已提交
1513 1514
			if (dst)
				dst = dst_check(dst, 0);
1515
			if (dst &&
E
Eric Dumazet 已提交
1516
			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1517
				skb_dst_set_noref(skb, dst);
D
David S. Miller 已提交
1518 1519 1520 1521
		}
	}
}

E
Eric Dumazet 已提交
1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539
/* Packet is added to VJ-style prequeue for processing in process
 * context, if a reader task is waiting. Apparently, this exciting
 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
 * failed somewhere. Latency? Burstiness? Well, at least now we will
 * see, why it failed. 8)8)				  --ANK
 *
 */
bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
{
	struct tcp_sock *tp = tcp_sk(sk);

	if (sysctl_tcp_low_latency || !tp->ucopy.task)
		return false;

	if (skb->len <= tcp_hdrlen(skb) &&
	    skb_queue_len(&tp->ucopy.prequeue) == 0)
		return false;

1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550
	/* Before escaping RCU protected region, we need to take care of skb
	 * dst. Prequeue is only enabled for established sockets.
	 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
	 * Instead of doing full sk_rx_dst validity here, let's perform
	 * an optimistic check.
	 */
	if (likely(sk->sk_rx_dst))
		skb_dst_drop(skb);
	else
		skb_dst_force(skb);

E
Eric Dumazet 已提交
1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
	__skb_queue_tail(&tp->ucopy.prequeue, skb);
	tp->ucopy.memory += skb->truesize;
	if (tp->ucopy.memory > sk->sk_rcvbuf) {
		struct sk_buff *skb1;

		BUG_ON(sock_owned_by_user(sk));

		while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
			sk_backlog_rcv(sk, skb1);
			NET_INC_STATS_BH(sock_net(sk),
					 LINUX_MIB_TCPPREQUEUEDROPPED);
		}

		tp->ucopy.memory = 0;
	} else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
		wake_up_interruptible_sync_poll(sk_sleep(sk),
					   POLLIN | POLLRDNORM | POLLRDBAND);
		if (!inet_csk_ack_scheduled(sk))
			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
						  (3 * tcp_rto_min(sk)) / 4,
						  TCP_RTO_MAX);
	}
	return true;
}
EXPORT_SYMBOL(tcp_prequeue);

L
Linus Torvalds 已提交
1577 1578 1579 1580 1581 1582
/*
 *	From tcp_input.c
 */

int tcp_v4_rcv(struct sk_buff *skb)
{
1583
	const struct iphdr *iph;
1584
	const struct tcphdr *th;
L
Linus Torvalds 已提交
1585 1586
	struct sock *sk;
	int ret;
1587
	struct net *net = dev_net(skb->dev);
L
Linus Torvalds 已提交
1588 1589 1590 1591 1592

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

	/* Count it even if it's bad */
1593
	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
L
Linus Torvalds 已提交
1594 1595 1596 1597

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

1598
	th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1599 1600 1601 1602 1603 1604 1605 1606

	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
1607
	 * provided case of th->doff==0 is eliminated.
L
Linus Torvalds 已提交
1608
	 * So, we defer the checks. */
1609 1610

	if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1611
		goto csum_error;
L
Linus Torvalds 已提交
1612

1613
	th = tcp_hdr(skb);
1614
	iph = ip_hdr(skb);
1615 1616 1617 1618 1619 1620 1621
	/* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
	 * barrier() makes sure compiler wont play fool^Waliasing games.
	 */
	memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
		sizeof(struct inet_skb_parm));
	barrier();

L
Linus Torvalds 已提交
1622 1623 1624 1625
	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);
1626
	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1627
	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1628
	TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
L
Linus Torvalds 已提交
1629 1630
	TCP_SKB_CB(skb)->sacked	 = 0;

1631
	sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
L
Linus Torvalds 已提交
1632 1633 1634
	if (!sk)
		goto no_tcp_socket;

E
Eric Dumazet 已提交
1635 1636 1637 1638
process:
	if (sk->sk_state == TCP_TIME_WAIT)
		goto do_time_wait;

1639 1640
	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1641
		goto discard_and_relse;
1642
	}
1643

L
Linus Torvalds 已提交
1644 1645
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;
1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657

#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_and_relse;
#endif

1658
	nf_reset(skb);
L
Linus Torvalds 已提交
1659

1660
	if (sk_filter(sk, skb))
L
Linus Torvalds 已提交
1661 1662
		goto discard_and_relse;

E
Eric Dumazet 已提交
1663
	sk_incoming_cpu_update(sk);
L
Linus Torvalds 已提交
1664 1665
	skb->dev = NULL;

1666
	bh_lock_sock_nested(sk);
L
Linus Torvalds 已提交
1667 1668
	ret = 0;
	if (!sock_owned_by_user(sk)) {
D
Dan Williams 已提交
1669
		if (!tcp_prequeue(sk, skb))
L
Linus Torvalds 已提交
1670
			ret = tcp_v4_do_rcv(sk, skb);
1671 1672
	} else if (unlikely(sk_add_backlog(sk, skb,
					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
Z
Zhu Yi 已提交
1673
		bh_unlock_sock(sk);
1674
		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
Z
Zhu Yi 已提交
1675 1676
		goto discard_and_relse;
	}
L
Linus Torvalds 已提交
1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687
	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)) {
1688 1689
csum_error:
		TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
L
Linus Torvalds 已提交
1690
bad_packet:
1691
		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1692
	} else {
1693
		tcp_v4_send_reset(NULL, skb);
L
Linus Torvalds 已提交
1694 1695 1696 1697 1698
	}

discard_it:
	/* Discard frame. */
	kfree_skb(skb);
1699
	return 0;
L
Linus Torvalds 已提交
1700 1701 1702 1703 1704 1705 1706

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1707
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1708 1709 1710
		goto discard_it;
	}

1711
	if (skb->len < (th->doff << 2)) {
1712
		inet_twsk_put(inet_twsk(sk));
1713 1714 1715 1716 1717
		goto bad_packet;
	}
	if (tcp_checksum_complete(skb)) {
		inet_twsk_put(inet_twsk(sk));
		goto csum_error;
L
Linus Torvalds 已提交
1718
	}
1719
	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
L
Linus Torvalds 已提交
1720
	case TCP_TW_SYN: {
1721
		struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1722
							&tcp_hashinfo,
1723
							iph->saddr, th->source,
1724
							iph->daddr, th->dest,
1725
							inet_iif(skb));
L
Linus Torvalds 已提交
1726
		if (sk2) {
1727 1728
			inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
			inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743
			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;
}

1744 1745 1746 1747 1748
static struct timewait_sock_ops tcp_timewait_sock_ops = {
	.twsk_obj_size	= sizeof(struct tcp_timewait_sock),
	.twsk_unique	= tcp_twsk_unique,
	.twsk_destructor= tcp_twsk_destructor,
};
L
Linus Torvalds 已提交
1749

1750
void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
E
Eric Dumazet 已提交
1751 1752 1753
{
	struct dst_entry *dst = skb_dst(skb);

1754 1755 1756 1757 1758
	if (dst) {
		dst_hold(dst);
		sk->sk_rx_dst = dst;
		inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
	}
E
Eric Dumazet 已提交
1759
}
1760
EXPORT_SYMBOL(inet_sk_rx_dst_set);
E
Eric Dumazet 已提交
1761

1762
const struct inet_connection_sock_af_ops ipv4_specific = {
1763 1764 1765
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
E
Eric Dumazet 已提交
1766
	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1767 1768 1769 1770 1771 1772 1773
	.conn_request	   = tcp_v4_conn_request,
	.syn_recv_sock	   = tcp_v4_syn_recv_sock,
	.net_header_len	   = sizeof(struct iphdr),
	.setsockopt	   = ip_setsockopt,
	.getsockopt	   = ip_getsockopt,
	.addr2sockaddr	   = inet_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in),
1774
	.bind_conflict	   = inet_csk_bind_conflict,
1775
#ifdef CONFIG_COMPAT
1776 1777
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
1778
#endif
1779
	.mtu_reduced	   = tcp_v4_mtu_reduced,
L
Linus Torvalds 已提交
1780
};
E
Eric Dumazet 已提交
1781
EXPORT_SYMBOL(ipv4_specific);
L
Linus Torvalds 已提交
1782

1783
#ifdef CONFIG_TCP_MD5SIG
1784
static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1785
	.md5_lookup		= tcp_v4_md5_lookup,
1786
	.calc_md5_hash		= tcp_v4_md5_hash_skb,
1787 1788
	.md5_parse		= tcp_v4_parse_md5_keys,
};
1789
#endif
1790

L
Linus Torvalds 已提交
1791 1792 1793 1794 1795
/* 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)
{
1796
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1797

1798
	tcp_init_sock(sk);
L
Linus Torvalds 已提交
1799

1800
	icsk->icsk_af_ops = &ipv4_specific;
1801

1802
#ifdef CONFIG_TCP_MD5SIG
1803
	tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1804
#endif
L
Linus Torvalds 已提交
1805 1806 1807 1808

	return 0;
}

1809
void tcp_v4_destroy_sock(struct sock *sk)
L
Linus Torvalds 已提交
1810 1811 1812 1813 1814
{
	struct tcp_sock *tp = tcp_sk(sk);

	tcp_clear_xmit_timers(sk);

1815
	tcp_cleanup_congestion_control(sk);
1816

L
Linus Torvalds 已提交
1817
	/* Cleanup up the write buffer. */
1818
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
1819 1820

	/* Cleans up our, hopefully empty, out_of_order_queue. */
1821
	__skb_queue_purge(&tp->out_of_order_queue);
L
Linus Torvalds 已提交
1822

1823 1824 1825
#ifdef CONFIG_TCP_MD5SIG
	/* Clean up the MD5 key list, if any */
	if (tp->md5sig_info) {
E
Eric Dumazet 已提交
1826
		tcp_clear_md5_list(sk);
1827
		kfree_rcu(tp->md5sig_info, rcu);
1828 1829 1830
		tp->md5sig_info = NULL;
	}
#endif
C
Chris Leech 已提交
1831

L
Linus Torvalds 已提交
1832 1833 1834 1835
	/* Clean prequeue, it must be empty really */
	__skb_queue_purge(&tp->ucopy.prequeue);

	/* Clean up a referenced TCP bind bucket. */
1836
	if (inet_csk(sk)->icsk_bind_hash)
1837
		inet_put_port(sk);
L
Linus Torvalds 已提交
1838

1839
	BUG_ON(tp->fastopen_rsk != NULL);
1840

1841 1842 1843
	/* If socket is aborted during connect operation */
	tcp_free_fastopen_req(tp);

1844
	sk_sockets_allocated_dec(sk);
G
Glauber Costa 已提交
1845
	sock_release_memcg(sk);
L
Linus Torvalds 已提交
1846 1847 1848 1849 1850 1851
}
EXPORT_SYMBOL(tcp_v4_destroy_sock);

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

1852 1853 1854 1855 1856
/*
 * Get next listener socket follow cur.  If cur is NULL, get first socket
 * starting from bucket given in st->bucket; when st->bucket is zero the
 * very first socket in the hash table is returned.
 */
L
Linus Torvalds 已提交
1857 1858
static void *listening_get_next(struct seq_file *seq, void *cur)
{
1859
	struct inet_connection_sock *icsk;
1860
	struct hlist_nulls_node *node;
L
Linus Torvalds 已提交
1861
	struct sock *sk = cur;
1862
	struct inet_listen_hashbucket *ilb;
J
Jianjun Kong 已提交
1863
	struct tcp_iter_state *st = seq->private;
1864
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1865 1866

	if (!sk) {
1867
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
1868
		spin_lock_bh(&ilb->lock);
1869
		sk = sk_nulls_head(&ilb->head);
1870
		st->offset = 0;
L
Linus Torvalds 已提交
1871 1872
		goto get_sk;
	}
1873
	ilb = &tcp_hashinfo.listening_hash[st->bucket];
L
Linus Torvalds 已提交
1874
	++st->num;
1875
	++st->offset;
L
Linus Torvalds 已提交
1876 1877

	if (st->state == TCP_SEQ_STATE_OPENREQ) {
1878
		struct request_sock *req = cur;
L
Linus Torvalds 已提交
1879

1880
		icsk = inet_csk(st->syn_wait_sk);
L
Linus Torvalds 已提交
1881 1882 1883
		req = req->dl_next;
		while (1) {
			while (req) {
1884
				if (req->rsk_ops->family == st->family) {
L
Linus Torvalds 已提交
1885 1886 1887 1888 1889
					cur = req;
					goto out;
				}
				req = req->dl_next;
			}
1890
			if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
L
Linus Torvalds 已提交
1891 1892
				break;
get_req:
1893
			req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
L
Linus Torvalds 已提交
1894
		}
E
Eric Dumazet 已提交
1895
		sk	  = sk_nulls_next(st->syn_wait_sk);
L
Linus Torvalds 已提交
1896
		st->state = TCP_SEQ_STATE_LISTENING;
1897
		spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
1898
	} else {
1899
		icsk = inet_csk(sk);
1900
		spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1901
		if (reqsk_queue_len(&icsk->icsk_accept_queue))
L
Linus Torvalds 已提交
1902
			goto start_req;
1903
		spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
E
Eric Dumazet 已提交
1904
		sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
1905 1906
	}
get_sk:
1907
	sk_nulls_for_each_from(sk, node) {
1908 1909 1910
		if (!net_eq(sock_net(sk), net))
			continue;
		if (sk->sk_family == st->family) {
L
Linus Torvalds 已提交
1911 1912 1913
			cur = sk;
			goto out;
		}
1914
		icsk = inet_csk(sk);
1915
		spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
1916
		if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
L
Linus Torvalds 已提交
1917 1918 1919 1920 1921 1922 1923
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;
		}
1924
		spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
1925
	}
1926
	spin_unlock_bh(&ilb->lock);
1927
	st->offset = 0;
1928
	if (++st->bucket < INET_LHTABLE_SIZE) {
1929 1930
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
		spin_lock_bh(&ilb->lock);
1931
		sk = sk_nulls_head(&ilb->head);
L
Linus Torvalds 已提交
1932 1933 1934 1935 1936 1937 1938 1939 1940
		goto get_sk;
	}
	cur = NULL;
out:
	return cur;
}

static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
{
1941 1942 1943 1944 1945 1946
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	st->offset = 0;
	rc = listening_get_next(seq, NULL);
L
Linus Torvalds 已提交
1947 1948 1949 1950 1951 1952 1953 1954

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

E
Eric Dumazet 已提交
1955
static inline bool empty_bucket(const struct tcp_iter_state *st)
1956
{
E
Eric Dumazet 已提交
1957
	return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1958 1959
}

1960 1961 1962 1963
/*
 * Get first established socket starting from bucket given in st->bucket.
 * If st->bucket is zero, the very first socket in the hash is returned.
 */
L
Linus Torvalds 已提交
1964 1965
static void *established_get_first(struct seq_file *seq)
{
J
Jianjun Kong 已提交
1966
	struct tcp_iter_state *st = seq->private;
1967
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1968 1969
	void *rc = NULL;

1970 1971
	st->offset = 0;
	for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
L
Linus Torvalds 已提交
1972
		struct sock *sk;
1973
		struct hlist_nulls_node *node;
1974
		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
L
Linus Torvalds 已提交
1975

1976 1977 1978 1979
		/* Lockless fast path for the common case of empty buckets */
		if (empty_bucket(st))
			continue;

1980
		spin_lock_bh(lock);
1981
		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1982
			if (sk->sk_family != st->family ||
1983
			    !net_eq(sock_net(sk), net)) {
L
Linus Torvalds 已提交
1984 1985 1986 1987 1988
				continue;
			}
			rc = sk;
			goto out;
		}
1989
		spin_unlock_bh(lock);
L
Linus Torvalds 已提交
1990 1991 1992 1993 1994 1995 1996 1997
	}
out:
	return rc;
}

static void *established_get_next(struct seq_file *seq, void *cur)
{
	struct sock *sk = cur;
1998
	struct hlist_nulls_node *node;
J
Jianjun Kong 已提交
1999
	struct tcp_iter_state *st = seq->private;
2000
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
2001 2002

	++st->num;
2003
	++st->offset;
L
Linus Torvalds 已提交
2004

E
Eric Dumazet 已提交
2005
	sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
2006

2007
	sk_nulls_for_each_from(sk, node) {
2008
		if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
E
Eric Dumazet 已提交
2009
			return sk;
L
Linus Torvalds 已提交
2010 2011
	}

E
Eric Dumazet 已提交
2012 2013 2014
	spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
	++st->bucket;
	return established_get_first(seq);
L
Linus Torvalds 已提交
2015 2016 2017 2018
}

static void *established_get_idx(struct seq_file *seq, loff_t pos)
{
2019 2020 2021 2022 2023
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	rc = established_get_first(seq);
L
Linus Torvalds 已提交
2024 2025 2026 2027

	while (rc && pos) {
		rc = established_get_next(seq, rc);
		--pos;
2028
	}
L
Linus Torvalds 已提交
2029 2030 2031 2032 2033 2034
	return rc;
}

static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
J
Jianjun Kong 已提交
2035
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047

	st->state = TCP_SEQ_STATE_LISTENING;
	rc	  = listening_get_idx(seq, &pos);

	if (!rc) {
		st->state = TCP_SEQ_STATE_ESTABLISHED;
		rc	  = established_get_idx(seq, pos);
	}

	return rc;
}

2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066
static void *tcp_seek_last_pos(struct seq_file *seq)
{
	struct tcp_iter_state *st = seq->private;
	int offset = st->offset;
	int orig_num = st->num;
	void *rc = NULL;

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
	case TCP_SEQ_STATE_LISTENING:
		if (st->bucket >= INET_LHTABLE_SIZE)
			break;
		st->state = TCP_SEQ_STATE_LISTENING;
		rc = listening_get_next(seq, NULL);
		while (offset-- && rc)
			rc = listening_get_next(seq, rc);
		if (rc)
			break;
		st->bucket = 0;
E
Eric Dumazet 已提交
2067
		st->state = TCP_SEQ_STATE_ESTABLISHED;
2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081
		/* Fallthrough */
	case TCP_SEQ_STATE_ESTABLISHED:
		if (st->bucket > tcp_hashinfo.ehash_mask)
			break;
		rc = established_get_first(seq);
		while (offset-- && rc)
			rc = established_get_next(seq, rc);
	}

	st->num = orig_num;

	return rc;
}

L
Linus Torvalds 已提交
2082 2083
static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
{
J
Jianjun Kong 已提交
2084
	struct tcp_iter_state *st = seq->private;
2085 2086 2087 2088 2089 2090 2091 2092
	void *rc;

	if (*pos && *pos == st->last_pos) {
		rc = tcp_seek_last_pos(seq);
		if (rc)
			goto out;
	}

L
Linus Torvalds 已提交
2093 2094
	st->state = TCP_SEQ_STATE_LISTENING;
	st->num = 0;
2095 2096 2097 2098 2099 2100 2101
	st->bucket = 0;
	st->offset = 0;
	rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;

out:
	st->last_pos = *pos;
	return rc;
L
Linus Torvalds 已提交
2102 2103 2104 2105
}

static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2106
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119
	void *rc = NULL;

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

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
	case TCP_SEQ_STATE_LISTENING:
		rc = listening_get_next(seq, v);
		if (!rc) {
			st->state = TCP_SEQ_STATE_ESTABLISHED;
2120 2121
			st->bucket = 0;
			st->offset = 0;
L
Linus Torvalds 已提交
2122 2123 2124 2125 2126 2127 2128 2129 2130
			rc	  = established_get_first(seq);
		}
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		rc = established_get_next(seq, v);
		break;
	}
out:
	++*pos;
2131
	st->last_pos = *pos;
L
Linus Torvalds 已提交
2132 2133 2134 2135 2136
	return rc;
}

static void tcp_seq_stop(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2137
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2138 2139 2140 2141

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
		if (v) {
2142
			struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
2143
			spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2144 2145 2146
		}
	case TCP_SEQ_STATE_LISTENING:
		if (v != SEQ_START_TOKEN)
2147
			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
L
Linus Torvalds 已提交
2148 2149 2150
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		if (v)
2151
			spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
L
Linus Torvalds 已提交
2152 2153 2154 2155
		break;
	}
}

2156
int tcp_seq_open(struct inode *inode, struct file *file)
L
Linus Torvalds 已提交
2157
{
A
Al Viro 已提交
2158
	struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
L
Linus Torvalds 已提交
2159
	struct tcp_iter_state *s;
2160
	int err;
L
Linus Torvalds 已提交
2161

2162 2163 2164 2165
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			  sizeof(struct tcp_iter_state));
	if (err < 0)
		return err;
2166

2167
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2168
	s->family		= afinfo->family;
S
stephen hemminger 已提交
2169
	s->last_pos		= 0;
2170 2171
	return 0;
}
2172
EXPORT_SYMBOL(tcp_seq_open);
2173

2174
int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2175 2176 2177 2178
{
	int rc = 0;
	struct proc_dir_entry *p;

2179 2180 2181 2182
	afinfo->seq_ops.start		= tcp_seq_start;
	afinfo->seq_ops.next		= tcp_seq_next;
	afinfo->seq_ops.stop		= tcp_seq_stop;

2183
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2184
			     afinfo->seq_fops, afinfo);
2185
	if (!p)
L
Linus Torvalds 已提交
2186 2187 2188
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2189
EXPORT_SYMBOL(tcp_proc_register);
L
Linus Torvalds 已提交
2190

2191
void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2192
{
2193
	remove_proc_entry(afinfo->name, net->proc_net);
L
Linus Torvalds 已提交
2194
}
E
Eric Dumazet 已提交
2195
EXPORT_SYMBOL(tcp_proc_unregister);
L
Linus Torvalds 已提交
2196

2197
static void get_openreq4(const struct request_sock *req,
2198
			 struct seq_file *f, int i, kuid_t uid)
L
Linus Torvalds 已提交
2199
{
2200
	const struct inet_request_sock *ireq = inet_rsk(req);
2201
	long delta = req->rsk_timer.expires - jiffies;
L
Linus Torvalds 已提交
2202

2203
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2204
		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
L
Linus Torvalds 已提交
2205
		i,
2206
		ireq->ir_loc_addr,
2207
		ireq->ir_num,
2208 2209
		ireq->ir_rmt_addr,
		ntohs(ireq->ir_rmt_port),
L
Linus Torvalds 已提交
2210 2211 2212
		TCP_SYN_RECV,
		0, 0, /* could print option size, but that is af dependent. */
		1,    /* timers active (only the expire timer) */
2213
		jiffies_delta_to_clock_t(delta),
2214
		req->num_timeout,
2215
		from_kuid_munged(seq_user_ns(f), uid),
L
Linus Torvalds 已提交
2216 2217
		0,  /* non standard timer */
		0, /* open_requests have no inode */
2218
		0,
2219
		req);
L
Linus Torvalds 已提交
2220 2221
}

2222
static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
L
Linus Torvalds 已提交
2223 2224 2225
{
	int timer_active;
	unsigned long timer_expires;
2226
	const struct tcp_sock *tp = tcp_sk(sk);
2227
	const struct inet_connection_sock *icsk = inet_csk(sk);
2228
	const struct inet_sock *inet = inet_sk(sk);
2229
	struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
E
Eric Dumazet 已提交
2230 2231 2232 2233
	__be32 dest = inet->inet_daddr;
	__be32 src = inet->inet_rcv_saddr;
	__u16 destp = ntohs(inet->inet_dport);
	__u16 srcp = ntohs(inet->inet_sport);
2234
	int rx_queue;
L
Linus Torvalds 已提交
2235

N
Nandita Dukkipati 已提交
2236 2237 2238
	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
	    icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
L
Linus Torvalds 已提交
2239
		timer_active	= 1;
2240 2241
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
Linus Torvalds 已提交
2242
		timer_active	= 4;
2243
		timer_expires	= icsk->icsk_timeout;
2244
	} else if (timer_pending(&sk->sk_timer)) {
L
Linus Torvalds 已提交
2245
		timer_active	= 2;
2246
		timer_expires	= sk->sk_timer.expires;
L
Linus Torvalds 已提交
2247 2248 2249 2250 2251
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

2252 2253 2254 2255 2256 2257 2258 2259
	if (sk->sk_state == TCP_LISTEN)
		rx_queue = sk->sk_ack_backlog;
	else
		/*
		 * because we dont lock socket, we might find a transient negative value
		 */
		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);

2260
	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2261
			"%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2262
		i, src, srcp, dest, destp, sk->sk_state,
2263
		tp->write_seq - tp->snd_una,
2264
		rx_queue,
L
Linus Torvalds 已提交
2265
		timer_active,
2266
		jiffies_delta_to_clock_t(timer_expires - jiffies),
2267
		icsk->icsk_retransmits,
2268
		from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2269
		icsk->icsk_probes_out,
2270 2271
		sock_i_ino(sk),
		atomic_read(&sk->sk_refcnt), sk,
2272 2273
		jiffies_to_clock_t(icsk->icsk_rto),
		jiffies_to_clock_t(icsk->icsk_ack.ato),
2274
		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
L
Linus Torvalds 已提交
2275
		tp->snd_cwnd,
2276 2277
		sk->sk_state == TCP_LISTEN ?
		    (fastopenq ? fastopenq->max_qlen : 0) :
2278
		    (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
L
Linus Torvalds 已提交
2279 2280
}

2281
static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2282
			       struct seq_file *f, int i)
L
Linus Torvalds 已提交
2283
{
2284
	__be32 dest, src;
L
Linus Torvalds 已提交
2285
	__u16 destp, srcp;
2286
	s32 delta = tw->tw_ttd - inet_tw_time_stamp();
L
Linus Torvalds 已提交
2287 2288 2289 2290 2291 2292

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

2293
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2294
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
L
Linus Torvalds 已提交
2295
		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2296
		3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2297
		atomic_read(&tw->tw_refcnt), tw);
L
Linus Torvalds 已提交
2298 2299 2300 2301 2302 2303
}

#define TMPSZ 150

static int tcp4_seq_show(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2304
	struct tcp_iter_state *st;
E
Eric Dumazet 已提交
2305
	struct sock *sk = v;
L
Linus Torvalds 已提交
2306

2307
	seq_setwidth(seq, TMPSZ - 1);
L
Linus Torvalds 已提交
2308
	if (v == SEQ_START_TOKEN) {
2309
		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
L
Linus Torvalds 已提交
2310 2311 2312 2313 2314 2315 2316 2317 2318
			   "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:
E
Eric Dumazet 已提交
2319
		if (sk->sk_state == TCP_TIME_WAIT)
2320
			get_timewait4_sock(v, seq, st->num);
E
Eric Dumazet 已提交
2321
		else
2322
			get_tcp4_sock(v, seq, st->num);
L
Linus Torvalds 已提交
2323 2324
		break;
	case TCP_SEQ_STATE_OPENREQ:
2325
		get_openreq4(v, seq, st->num, st->uid);
L
Linus Torvalds 已提交
2326 2327 2328
		break;
	}
out:
2329
	seq_pad(seq, '\n');
L
Linus Torvalds 已提交
2330 2331 2332
	return 0;
}

2333 2334 2335 2336 2337 2338 2339 2340
static const struct file_operations tcp_afinfo_seq_fops = {
	.owner   = THIS_MODULE,
	.open    = tcp_seq_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release_net
};

L
Linus Torvalds 已提交
2341 2342 2343
static struct tcp_seq_afinfo tcp4_seq_afinfo = {
	.name		= "tcp",
	.family		= AF_INET,
2344
	.seq_fops	= &tcp_afinfo_seq_fops,
2345 2346 2347
	.seq_ops	= {
		.show		= tcp4_seq_show,
	},
L
Linus Torvalds 已提交
2348 2349
};

2350
static int __net_init tcp4_proc_init_net(struct net *net)
2351 2352 2353 2354
{
	return tcp_proc_register(net, &tcp4_seq_afinfo);
}

2355
static void __net_exit tcp4_proc_exit_net(struct net *net)
2356 2357 2358 2359 2360 2361 2362 2363 2364
{
	tcp_proc_unregister(net, &tcp4_seq_afinfo);
}

static struct pernet_operations tcp4_net_ops = {
	.init = tcp4_proc_init_net,
	.exit = tcp4_proc_exit_net,
};

L
Linus Torvalds 已提交
2365 2366
int __init tcp4_proc_init(void)
{
2367
	return register_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2368 2369 2370 2371
}

void tcp4_proc_exit(void)
{
2372
	unregister_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2373 2374 2375 2376 2377 2378 2379 2380 2381
}
#endif /* CONFIG_PROC_FS */

struct proto tcp_prot = {
	.name			= "TCP",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v4_connect,
	.disconnect		= tcp_disconnect,
2382
	.accept			= inet_csk_accept,
L
Linus Torvalds 已提交
2383 2384 2385 2386 2387 2388 2389
	.ioctl			= tcp_ioctl,
	.init			= tcp_v4_init_sock,
	.destroy		= tcp_v4_destroy_sock,
	.shutdown		= tcp_shutdown,
	.setsockopt		= tcp_setsockopt,
	.getsockopt		= tcp_getsockopt,
	.recvmsg		= tcp_recvmsg,
2390 2391
	.sendmsg		= tcp_sendmsg,
	.sendpage		= tcp_sendpage,
L
Linus Torvalds 已提交
2392
	.backlog_rcv		= tcp_v4_do_rcv,
E
Eric Dumazet 已提交
2393
	.release_cb		= tcp_release_cb,
2394 2395 2396
	.hash			= inet_hash,
	.unhash			= inet_unhash,
	.get_port		= inet_csk_get_port,
L
Linus Torvalds 已提交
2397
	.enter_memory_pressure	= tcp_enter_memory_pressure,
2398
	.stream_memory_free	= tcp_stream_memory_free,
L
Linus Torvalds 已提交
2399
	.sockets_allocated	= &tcp_sockets_allocated,
2400
	.orphan_count		= &tcp_orphan_count,
L
Linus Torvalds 已提交
2401 2402
	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
2403
	.sysctl_mem		= sysctl_tcp_mem,
L
Linus Torvalds 已提交
2404 2405 2406 2407
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp_sock),
2408
	.slab_flags		= SLAB_DESTROY_BY_RCU,
2409
	.twsk_prot		= &tcp_timewait_sock_ops,
2410
	.rsk_prot		= &tcp_request_sock_ops,
2411
	.h.hashinfo		= &tcp_hashinfo,
2412
	.no_autobind		= true,
2413 2414 2415 2416
#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
#endif
A
Andrew Morton 已提交
2417
#ifdef CONFIG_MEMCG_KMEM
G
Glauber Costa 已提交
2418 2419 2420 2421
	.init_cgroup		= tcp_init_cgroup,
	.destroy_cgroup		= tcp_destroy_cgroup,
	.proto_cgroup		= tcp_proto_cgroup,
#endif
L
Linus Torvalds 已提交
2422
};
E
Eric Dumazet 已提交
2423
EXPORT_SYMBOL(tcp_prot);
L
Linus Torvalds 已提交
2424

2425 2426 2427 2428 2429 2430 2431 2432 2433
static void __net_exit tcp_sk_exit(struct net *net)
{
	int cpu;

	for_each_possible_cpu(cpu)
		inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
	free_percpu(net->ipv4.tcp_sk);
}

2434 2435
static int __net_init tcp_sk_init(struct net *net)
{
2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450
	int res, cpu;

	net->ipv4.tcp_sk = alloc_percpu(struct sock *);
	if (!net->ipv4.tcp_sk)
		return -ENOMEM;

	for_each_possible_cpu(cpu) {
		struct sock *sk;

		res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
					   IPPROTO_TCP, net);
		if (res)
			goto fail;
		*per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
	}
2451
	net->ipv4.sysctl_tcp_ecn = 2;
F
Fan Du 已提交
2452
	net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2453
	net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2454
	net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2455
	return 0;
2456

2457 2458 2459 2460
fail:
	tcp_sk_exit(net);

	return res;
E
Eric W. Biederman 已提交
2461 2462 2463 2464 2465
}

static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
{
	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2466 2467 2468
}

static struct pernet_operations __net_initdata tcp_sk_ops = {
E
Eric W. Biederman 已提交
2469 2470 2471
       .init	   = tcp_sk_init,
       .exit	   = tcp_sk_exit,
       .exit_batch = tcp_sk_exit_batch,
2472 2473
};

2474
void __init tcp_v4_init(void)
L
Linus Torvalds 已提交
2475
{
2476
	inet_hashinfo_init(&tcp_hashinfo);
2477
	if (register_pernet_subsys(&tcp_sk_ops))
L
Linus Torvalds 已提交
2478 2479
		panic("Failed to create the TCP control socket.\n");
}