tcp.c 85.8 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7
/*
 * 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).
 *
8
 * Authors:	Ross Biro
L
Linus Torvalds 已提交
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 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Mark Evans, <evansmp@uhura.aston.ac.uk>
 *		Corey Minyard <wf-rch!minyard@relay.EU.net>
 *		Florian La Roche, <flla@stud.uni-sb.de>
 *		Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
 *		Linus Torvalds, <torvalds@cs.helsinki.fi>
 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 *		Matthew Dillon, <dillon@apollo.west.oic.com>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *		Jorge Cwik, <jorge@laser.satlink.net>
 *
 * Fixes:
 *		Alan Cox	:	Numerous verify_area() calls
 *		Alan Cox	:	Set the ACK bit on a reset
 *		Alan Cox	:	Stopped it crashing if it closed while
 *					sk->inuse=1 and was trying to connect
 *					(tcp_err()).
 *		Alan Cox	:	All icmp error handling was broken
 *					pointers passed where wrong and the
 *					socket was looked up backwards. Nobody
 *					tested any icmp error code obviously.
 *		Alan Cox	:	tcp_err() now handled properly. It
 *					wakes people on errors. poll
 *					behaves and the icmp error race
 *					has gone by moving it into sock.c
 *		Alan Cox	:	tcp_send_reset() fixed to work for
 *					everything not just packets for
 *					unknown sockets.
 *		Alan Cox	:	tcp option processing.
 *		Alan Cox	:	Reset tweaked (still not 100%) [Had
 *					syn rule wrong]
 *		Herp Rosmanith  :	More reset fixes
 *		Alan Cox	:	No longer acks invalid rst frames.
 *					Acking any kind of RST is right out.
 *		Alan Cox	:	Sets an ignore me flag on an rst
 *					receive otherwise odd bits of prattle
 *					escape still
 *		Alan Cox	:	Fixed another acking RST frame bug.
 *					Should stop LAN workplace lockups.
 *		Alan Cox	: 	Some tidyups using the new skb list
 *					facilities
 *		Alan Cox	:	sk->keepopen now seems to work
 *		Alan Cox	:	Pulls options out correctly on accepts
 *		Alan Cox	:	Fixed assorted sk->rqueue->next errors
 *		Alan Cox	:	PSH doesn't end a TCP read. Switched a
 *					bit to skb ops.
 *		Alan Cox	:	Tidied tcp_data to avoid a potential
 *					nasty.
 *		Alan Cox	:	Added some better commenting, as the
 *					tcp is hard to follow
 *		Alan Cox	:	Removed incorrect check for 20 * psh
 *	Michael O'Reilly	:	ack < copied bug fix.
 *	Johannes Stille		:	Misc tcp fixes (not all in yet).
 *		Alan Cox	:	FIN with no memory -> CRASH
 *		Alan Cox	:	Added socket option proto entries.
 *					Also added awareness of them to accept.
 *		Alan Cox	:	Added TCP options (SOL_TCP)
 *		Alan Cox	:	Switched wakeup calls to callbacks,
 *					so the kernel can layer network
 *					sockets.
 *		Alan Cox	:	Use ip_tos/ip_ttl settings.
 *		Alan Cox	:	Handle FIN (more) properly (we hope).
 *		Alan Cox	:	RST frames sent on unsynchronised
 *					state ack error.
 *		Alan Cox	:	Put in missing check for SYN bit.
 *		Alan Cox	:	Added tcp_select_window() aka NET2E
 *					window non shrink trick.
 *		Alan Cox	:	Added a couple of small NET2E timer
 *					fixes
 *		Charles Hedrick :	TCP fixes
 *		Toomas Tamm	:	TCP window fixes
 *		Alan Cox	:	Small URG fix to rlogin ^C ack fight
 *		Charles Hedrick	:	Rewrote most of it to actually work
 *		Linus		:	Rewrote tcp_read() and URG handling
 *					completely
 *		Gerhard Koerting:	Fixed some missing timer handling
 *		Matthew Dillon  :	Reworked TCP machine states as per RFC
 *		Gerhard Koerting:	PC/TCP workarounds
 *		Adam Caldwell	:	Assorted timer/timing errors
 *		Matthew Dillon	:	Fixed another RST bug
 *		Alan Cox	:	Move to kernel side addressing changes.
 *		Alan Cox	:	Beginning work on TCP fastpathing
 *					(not yet usable)
 *		Arnt Gulbrandsen:	Turbocharged tcp_check() routine.
 *		Alan Cox	:	TCP fast path debugging
 *		Alan Cox	:	Window clamping
 *		Michael Riepe	:	Bug in tcp_check()
 *		Matt Dillon	:	More TCP improvements and RST bug fixes
 *		Matt Dillon	:	Yet more small nasties remove from the
 *					TCP code (Be very nice to this man if
 *					tcp finally works 100%) 8)
 *		Alan Cox	:	BSD accept semantics.
 *		Alan Cox	:	Reset on closedown bug.
 *	Peter De Schrijver	:	ENOTCONN check missing in tcp_sendto().
 *		Michael Pall	:	Handle poll() after URG properly in
 *					all cases.
 *		Michael Pall	:	Undo the last fix in tcp_read_urg()
 *					(multi URG PUSH broke rlogin).
 *		Michael Pall	:	Fix the multi URG PUSH problem in
 *					tcp_readable(), poll() after URG
 *					works now.
 *		Michael Pall	:	recv(...,MSG_OOB) never blocks in the
 *					BSD api.
 *		Alan Cox	:	Changed the semantics of sk->socket to
 *					fix a race and a signal problem with
 *					accept() and async I/O.
 *		Alan Cox	:	Relaxed the rules on tcp_sendto().
 *		Yury Shevchuk	:	Really fixed accept() blocking problem.
 *		Craig I. Hagan  :	Allow for BSD compatible TIME_WAIT for
 *					clients/servers which listen in on
 *					fixed ports.
 *		Alan Cox	:	Cleaned the above up and shrank it to
 *					a sensible code size.
 *		Alan Cox	:	Self connect lockup fix.
 *		Alan Cox	:	No connect to multicast.
 *		Ross Biro	:	Close unaccepted children on master
 *					socket close.
 *		Alan Cox	:	Reset tracing code.
 *		Alan Cox	:	Spurious resets on shutdown.
 *		Alan Cox	:	Giant 15 minute/60 second timer error
 *		Alan Cox	:	Small whoops in polling before an
 *					accept.
 *		Alan Cox	:	Kept the state trace facility since
 *					it's handy for debugging.
 *		Alan Cox	:	More reset handler fixes.
 *		Alan Cox	:	Started rewriting the code based on
 *					the RFC's for other useful protocol
 *					references see: Comer, KA9Q NOS, and
 *					for a reference on the difference
 *					between specifications and how BSD
 *					works see the 4.4lite source.
 *		A.N.Kuznetsov	:	Don't time wait on completion of tidy
 *					close.
 *		Linus Torvalds	:	Fin/Shutdown & copied_seq changes.
 *		Linus Torvalds	:	Fixed BSD port reuse to work first syn
 *		Alan Cox	:	Reimplemented timers as per the RFC
 *					and using multiple timers for sanity.
 *		Alan Cox	:	Small bug fixes, and a lot of new
 *					comments.
 *		Alan Cox	:	Fixed dual reader crash by locking
 *					the buffers (much like datagram.c)
 *		Alan Cox	:	Fixed stuck sockets in probe. A probe
 *					now gets fed up of retrying without
 *					(even a no space) answer.
 *		Alan Cox	:	Extracted closing code better
 *		Alan Cox	:	Fixed the closing state machine to
 *					resemble the RFC.
 *		Alan Cox	:	More 'per spec' fixes.
 *		Jorge Cwik	:	Even faster checksumming.
 *		Alan Cox	:	tcp_data() doesn't ack illegal PSH
 *					only frames. At least one pc tcp stack
 *					generates them.
 *		Alan Cox	:	Cache last socket.
 *		Alan Cox	:	Per route irtt.
 *		Matt Day	:	poll()->select() match BSD precisely on error
 *		Alan Cox	:	New buffers
 *		Marc Tamsky	:	Various sk->prot->retransmits and
 *					sk->retransmits misupdating fixed.
 *					Fixed tcp_write_timeout: stuck close,
 *					and TCP syn retries gets used now.
 *		Mark Yarvis	:	In tcp_read_wakeup(), don't send an
 *					ack if state is TCP_CLOSED.
 *		Alan Cox	:	Look up device on a retransmit - routes may
 *					change. Doesn't yet cope with MSS shrink right
 *					but it's a start!
 *		Marc Tamsky	:	Closing in closing fixes.
 *		Mike Shaver	:	RFC1122 verifications.
 *		Alan Cox	:	rcv_saddr errors.
 *		Alan Cox	:	Block double connect().
 *		Alan Cox	:	Small hooks for enSKIP.
 *		Alexey Kuznetsov:	Path MTU discovery.
 *		Alan Cox	:	Support soft errors.
 *		Alan Cox	:	Fix MTU discovery pathological case
 *					when the remote claims no mtu!
 *		Marc Tamsky	:	TCP_CLOSE fix.
 *		Colin (G3TNE)	:	Send a reset on syn ack replies in
 *					window but wrong (fixes NT lpd problems)
 *		Pedro Roque	:	Better TCP window handling, delayed ack.
 *		Joerg Reuter	:	No modification of locked buffers in
 *					tcp_do_retransmit()
 *		Eric Schenk	:	Changed receiver side silly window
 *					avoidance algorithm to BSD style
 *					algorithm. This doubles throughput
 *					against machines running Solaris,
 *					and seems to result in general
 *					improvement.
 *	Stefan Magdalinski	:	adjusted tcp_readable() to fix FIONREAD
 *	Willy Konynenberg	:	Transparent proxying support.
 *	Mike McLagan		:	Routing by source
 *		Keith Owens	:	Do proper merging with partial SKB's in
 *					tcp_do_sendmsg to avoid burstiness.
 *		Eric Schenk	:	Fix fast close down bug with
 *					shutdown() followed by close().
 *		Andi Kleen 	:	Make poll agree with SIGIO
 *	Salvatore Sanfilippo	:	Support SO_LINGER with linger == 1 and
 *					lingertime == 0 (RFC 793 ABORT Call)
 *	Hirokazu Takahashi	:	Use copy_from_user() instead of
 *					csum_and_copy_from_user() if possible.
 *
 *		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.
 *
 * Description of States:
 *
 *	TCP_SYN_SENT		sent a connection request, waiting for ack
 *
 *	TCP_SYN_RECV		received a connection request, sent ack,
 *				waiting for final ack in three-way handshake.
 *
 *	TCP_ESTABLISHED		connection established
 *
 *	TCP_FIN_WAIT1		our side has shutdown, waiting to complete
 *				transmission of remaining buffered data
 *
 *	TCP_FIN_WAIT2		all buffered data sent, waiting for remote
 *				to shutdown
 *
 *	TCP_CLOSING		both sides have shutdown but we still have
 *				data we have to finish sending
 *
 *	TCP_TIME_WAIT		timeout to catch resent junk before entering
 *				closed, can only be entered from FIN_WAIT2
 *				or CLOSING.  Required because the other end
 *				may not have gotten our last ACK causing it
 *				to retransmit the data packet (which we ignore)
 *
 *	TCP_CLOSE_WAIT		remote side has shutdown and is waiting for
 *				us to finish writing our data and to shutdown
 *				(we have to close() to move on to LAST_ACK)
 *
 *	TCP_LAST_ACK		out side has shutdown after remote has
 *				shutdown.  There may still be data in our
 *				buffer that we have to finish sending
 *
 *	TCP_CLOSE		socket is finished
 */

248
#include <linux/kernel.h>
L
Linus Torvalds 已提交
249 250 251 252 253 254
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
J
Jens Axboe 已提交
255
#include <linux/skbuff.h>
256
#include <linux/scatterlist.h>
J
Jens Axboe 已提交
257 258 259
#include <linux/splice.h>
#include <linux/net.h>
#include <linux/socket.h>
L
Linus Torvalds 已提交
260 261
#include <linux/random.h>
#include <linux/bootmem.h>
262 263
#include <linux/highmem.h>
#include <linux/swap.h>
264
#include <linux/cache.h>
H
Herbert Xu 已提交
265
#include <linux/err.h>
266
#include <linux/crypto.h>
267
#include <linux/time.h>
268
#include <linux/slab.h>
L
Linus Torvalds 已提交
269 270 271 272 273

#include <net/icmp.h>
#include <net/tcp.h>
#include <net/xfrm.h>
#include <net/ip.h>
C
Chris Leech 已提交
274
#include <net/netdma.h>
J
Jens Axboe 已提交
275
#include <net/sock.h>
L
Linus Torvalds 已提交
276 277 278 279

#include <asm/uaccess.h>
#include <asm/ioctls.h>

280
int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
L
Linus Torvalds 已提交
281

282
struct percpu_counter tcp_orphan_count;
283 284
EXPORT_SYMBOL_GPL(tcp_orphan_count);

285 286 287
int sysctl_tcp_mem[3] __read_mostly;
int sysctl_tcp_wmem[3] __read_mostly;
int sysctl_tcp_rmem[3] __read_mostly;
L
Linus Torvalds 已提交
288 289 290 291 292 293 294

EXPORT_SYMBOL(sysctl_tcp_mem);
EXPORT_SYMBOL(sysctl_tcp_rmem);
EXPORT_SYMBOL(sysctl_tcp_wmem);

atomic_t tcp_memory_allocated;	/* Current allocated memory. */
EXPORT_SYMBOL(tcp_memory_allocated);
295 296 297 298 299

/*
 * Current number of TCP sockets.
 */
struct percpu_counter tcp_sockets_allocated;
L
Linus Torvalds 已提交
300 301
EXPORT_SYMBOL(tcp_sockets_allocated);

J
Jens Axboe 已提交
302 303 304 305 306 307 308 309 310
/*
 * TCP splice context
 */
struct tcp_splice_state {
	struct pipe_inode_info *pipe;
	size_t len;
	unsigned int flags;
};

L
Linus Torvalds 已提交
311 312 313
/*
 * Pressure flag: try to collapse.
 * Technical note: it is used by multiple contexts non atomically.
314
 * All the __sk_mem_schedule() is of this nature: accounting
L
Linus Torvalds 已提交
315 316
 * is strict, actions are advisory and have some latency.
 */
317
int tcp_memory_pressure __read_mostly;
L
Linus Torvalds 已提交
318 319 320

EXPORT_SYMBOL(tcp_memory_pressure);

321
void tcp_enter_memory_pressure(struct sock *sk)
L
Linus Torvalds 已提交
322 323
{
	if (!tcp_memory_pressure) {
P
Pavel Emelyanov 已提交
324
		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
L
Linus Torvalds 已提交
325 326 327 328 329 330
		tcp_memory_pressure = 1;
	}
}

EXPORT_SYMBOL(tcp_enter_memory_pressure);

331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367
/* Convert seconds to retransmits based on initial and max timeout */
static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
{
	u8 res = 0;

	if (seconds > 0) {
		int period = timeout;

		res = 1;
		while (seconds > period && res < 255) {
			res++;
			timeout <<= 1;
			if (timeout > rto_max)
				timeout = rto_max;
			period += timeout;
		}
	}
	return res;
}

/* Convert retransmits to seconds based on initial and max timeout */
static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
{
	int period = 0;

	if (retrans > 0) {
		period = timeout;
		while (--retrans) {
			timeout <<= 1;
			if (timeout > rto_max)
				timeout = rto_max;
			period += timeout;
		}
	}
	return period;
}

L
Linus Torvalds 已提交
368 369 370 371 372 373 374 375 376 377 378 379 380
/*
 *	Wait for a TCP event.
 *
 *	Note that we don't need to lock the socket, as the upper poll layers
 *	take care of normal races (between the test and the event) and we don't
 *	go look at any of the socket buffers directly.
 */
unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
	unsigned int mask;
	struct sock *sk = sock->sk;
	struct tcp_sock *tp = tcp_sk(sk);

E
Eric Dumazet 已提交
381
	sock_poll_wait(file, sk_sleep(sk), wait);
L
Linus Torvalds 已提交
382
	if (sk->sk_state == TCP_LISTEN)
383
		return inet_csk_listen_poll(sk);
L
Linus Torvalds 已提交
384 385

	/* Socket is not locked. We are protected from async events
386 387
	 * by poll logic and correct handling of state changes
	 * made by other threads is impossible in any case.
L
Linus Torvalds 已提交
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
	 */

	mask = 0;
	if (sk->sk_err)
		mask = POLLERR;

	/*
	 * POLLHUP is certainly not done right. But poll() doesn't
	 * have a notion of HUP in just one direction, and for a
	 * socket the read side is more interesting.
	 *
	 * Some poll() documentation says that POLLHUP is incompatible
	 * with the POLLOUT/POLLWR flags, so somebody should check this
	 * all. But careful, it tends to be safer to return too many
	 * bits than too few, and you can easily break real applications
	 * if you don't tell them that something has hung up!
	 *
	 * Check-me.
	 *
	 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
	 * our fs/select.c). It means that after we received EOF,
	 * poll always returns immediately, making impossible poll() on write()
	 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
	 * if and only if shutdown has been made in both directions.
	 * Actually, it is interesting to look how Solaris and DUX
413
	 * solve this dilemma. I would prefer, if POLLHUP were maskable,
L
Linus Torvalds 已提交
414 415
	 * then we could set it on SND_SHUTDOWN. BTW examples given
	 * in Stevens' books assume exactly this behaviour, it explains
416
	 * why POLLHUP is incompatible with POLLOUT.	--ANK
L
Linus Torvalds 已提交
417 418 419 420 421 422 423
	 *
	 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
	 * blocking on fresh not-connected or disconnected socket. --ANK
	 */
	if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
		mask |= POLLHUP;
	if (sk->sk_shutdown & RCV_SHUTDOWN)
424
		mask |= POLLIN | POLLRDNORM | POLLRDHUP;
L
Linus Torvalds 已提交
425 426 427

	/* Connected? */
	if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
428 429 430 431 432
		int target = sock_rcvlowat(sk, 0, INT_MAX);

		if (tp->urg_seq == tp->copied_seq &&
		    !sock_flag(sk, SOCK_URGINLINE) &&
		    tp->urg_data)
433
			target++;
434

L
Linus Torvalds 已提交
435 436 437
		/* Potential race condition. If read of tp below will
		 * escape above sk->sk_state, we can be illegally awaken
		 * in SYN_* states. */
438
		if (tp->rcv_nxt - tp->copied_seq >= target)
L
Linus Torvalds 已提交
439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480
			mask |= POLLIN | POLLRDNORM;

		if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
			if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
				mask |= POLLOUT | POLLWRNORM;
			} else {  /* send SIGIO later */
				set_bit(SOCK_ASYNC_NOSPACE,
					&sk->sk_socket->flags);
				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);

				/* Race breaker. If space is freed after
				 * wspace test but before the flags are set,
				 * IO signal will be lost.
				 */
				if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
					mask |= POLLOUT | POLLWRNORM;
			}
		}

		if (tp->urg_data & TCP_URG_VALID)
			mask |= POLLPRI;
	}
	return mask;
}

int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int answ;

	switch (cmd) {
	case SIOCINQ:
		if (sk->sk_state == TCP_LISTEN)
			return -EINVAL;

		lock_sock(sk);
		if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
			answ = 0;
		else if (sock_flag(sk, SOCK_URGINLINE) ||
			 !tp->urg_data ||
			 before(tp->urg_seq, tp->copied_seq) ||
			 !before(tp->urg_seq, tp->rcv_nxt)) {
481 482
			struct sk_buff *skb;

L
Linus Torvalds 已提交
483 484 485
			answ = tp->rcv_nxt - tp->copied_seq;

			/* Subtract 1, if FIN is in queue. */
486 487 488
			skb = skb_peek_tail(&sk->sk_receive_queue);
			if (answ && skb)
				answ -= tcp_hdr(skb)->fin;
L
Linus Torvalds 已提交
489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506
		} else
			answ = tp->urg_seq - tp->copied_seq;
		release_sock(sk);
		break;
	case SIOCATMARK:
		answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
		break;
	case SIOCOUTQ:
		if (sk->sk_state == TCP_LISTEN)
			return -EINVAL;

		if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
			answ = 0;
		else
			answ = tp->write_seq - tp->snd_una;
		break;
	default:
		return -ENOIOCTLCMD;
507
	}
L
Linus Torvalds 已提交
508 509 510 511 512 513 514 515 516 517 518 519 520 521 522

	return put_user(answ, (int __user *)arg);
}

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
	TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_PSH;
	tp->pushed_seq = tp->write_seq;
}

static inline int forced_push(struct tcp_sock *tp)
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

523
static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
524
{
525
	struct tcp_sock *tp = tcp_sk(sk);
526 527 528 529 530 531
	struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);

	skb->csum    = 0;
	tcb->seq     = tcb->end_seq = tp->write_seq;
	tcb->flags   = TCPCB_FLAG_ACK;
	tcb->sacked  = 0;
L
Linus Torvalds 已提交
532
	skb_header_release(skb);
533
	tcp_add_write_queue_tail(sk, skb);
534 535
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
536
	if (tp->nonagle & TCP_NAGLE_PUSH)
537
		tp->nonagle &= ~TCP_NAGLE_PUSH;
L
Linus Torvalds 已提交
538 539
}

540
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
541
{
I
Ilpo Järvinen 已提交
542
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
543 544 545
		tp->snd_up = tp->write_seq;
}

546 547
static inline void tcp_push(struct sock *sk, int flags, int mss_now,
			    int nonagle)
L
Linus Torvalds 已提交
548
{
549
	if (tcp_send_head(sk)) {
550 551
		struct tcp_sock *tp = tcp_sk(sk);

L
Linus Torvalds 已提交
552
		if (!(flags & MSG_MORE) || forced_push(tp))
553 554 555
			tcp_mark_push(tp, tcp_write_queue_tail(sk));

		tcp_mark_urg(tp, flags);
556
		__tcp_push_pending_frames(sk, mss_now,
L
Linus Torvalds 已提交
557 558 559 560
					  (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
	}
}

561 562
static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
				unsigned int offset, size_t len)
J
Jens Axboe 已提交
563 564
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
565
	int ret;
J
Jens Axboe 已提交
566

567 568
	ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
			      tss->flags);
569 570 571
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
572 573 574 575 576 577 578
}

static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
{
	/* Store TCP splice context information in read_descriptor_t. */
	read_descriptor_t rd_desc = {
		.arg.data = tss,
579
		.count	  = tss->len,
J
Jens Axboe 已提交
580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
	};

	return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
}

/**
 *  tcp_splice_read - splice data from TCP socket to a pipe
 * @sock:	socket to splice from
 * @ppos:	position (not valid)
 * @pipe:	pipe to splice to
 * @len:	number of bytes to splice
 * @flags:	splice modifier flags
 *
 * Description:
 *    Will read pages from given socket and fill them into a pipe.
 *
 **/
ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
			struct pipe_inode_info *pipe, size_t len,
			unsigned int flags)
{
	struct sock *sk = sock->sk;
	struct tcp_splice_state tss = {
		.pipe = pipe,
		.len = len,
		.flags = flags,
	};
	long timeo;
	ssize_t spliced;
	int ret;

	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

621
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659
	while (tss.len) {
		ret = __tcp_splice_read(sk, &tss);
		if (ret < 0)
			break;
		else if (!ret) {
			if (spliced)
				break;
			if (sock_flag(sk, SOCK_DONE))
				break;
			if (sk->sk_err) {
				ret = sock_error(sk);
				break;
			}
			if (sk->sk_shutdown & RCV_SHUTDOWN)
				break;
			if (sk->sk_state == TCP_CLOSE) {
				/*
				 * This occurs when user tries to read
				 * from never connected socket.
				 */
				if (!sock_flag(sk, SOCK_DONE))
					ret = -ENOTCONN;
				break;
			}
			if (!timeo) {
				ret = -EAGAIN;
				break;
			}
			sk_wait_data(sk, &timeo);
			if (signal_pending(current)) {
				ret = sock_intr_errno(timeo);
				break;
			}
			continue;
		}
		tss.len -= ret;
		spliced += ret;

660 661
		if (!timeo)
			break;
J
Jens Axboe 已提交
662 663 664 665
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
666
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
667 668 669 670 671 672 673 674 675 676 677 678
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}

679
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
680 681 682 683 684 685 686 687
{
	struct sk_buff *skb;

	/* The TCP header must be at least 32-bit aligned.  */
	size = ALIGN(size, 4);

	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
	if (skb) {
688
		if (sk_wmem_schedule(sk, skb->truesize)) {
689 690 691 692 693 694 695 696 697
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
			skb_reserve(skb, skb_tailroom(skb) - size);
			return skb;
		}
		__kfree_skb(skb);
	} else {
698
		sk->sk_prot->enter_memory_pressure(sk);
699 700 701 702 703
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
704 705 706 707
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
708
	u32 xmit_size_goal, old_size_goal;
I
Ilpo Järvinen 已提交
709 710 711 712 713 714 715 716 717 718

	xmit_size_goal = mss_now;

	if (large_allowed && sk_can_gso(sk)) {
		xmit_size_goal = ((sk->sk_gso_max_size - 1) -
				  inet_csk(sk)->icsk_af_ops->net_header_len -
				  inet_csk(sk)->icsk_ext_hdr_len -
				  tp->tcp_header_len);

		xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
719 720 721 722 723 724 725 726 727 728 729

		/* We try hard to avoid divides here */
		old_size_goal = tp->xmit_size_goal_segs * mss_now;

		if (likely(old_size_goal <= xmit_size_goal &&
			   old_size_goal + mss_now > xmit_size_goal)) {
			xmit_size_goal = old_size_goal;
		} else {
			tp->xmit_size_goal_segs = xmit_size_goal / mss_now;
			xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
		}
I
Ilpo Järvinen 已提交
730 731
	}

732
	return max(xmit_size_goal, mss_now);
I
Ilpo Järvinen 已提交
733 734 735 736 737 738 739 740 741 742 743 744
}

static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
{
	int mss_now;

	mss_now = tcp_current_mss(sk);
	*size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));

	return mss_now;
}

L
Linus Torvalds 已提交
745 746 747 748
static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffset,
			 size_t psize, int flags)
{
	struct tcp_sock *tp = tcp_sk(sk);
749
	int mss_now, size_goal;
L
Linus Torvalds 已提交
750 751 752 753 754 755 756 757 758 759 760
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

	/* Wait for a connection to finish. */
	if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_err;

	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

I
Ilpo Järvinen 已提交
761
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
762 763 764 765
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
766
		goto out_err;
L
Linus Torvalds 已提交
767 768

	while (psize > 0) {
769
		struct sk_buff *skb = tcp_write_queue_tail(sk);
L
Linus Torvalds 已提交
770 771 772 773 774
		struct page *page = pages[poffset / PAGE_SIZE];
		int copy, i, can_coalesce;
		int offset = poffset % PAGE_SIZE;
		int size = min_t(size_t, psize, PAGE_SIZE - offset);

775
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
776 777 778 779
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

780
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
L
Linus Torvalds 已提交
781 782 783
			if (!skb)
				goto wait_for_memory;

784
			skb_entail(sk, skb);
785
			copy = size_goal;
L
Linus Torvalds 已提交
786 787 788 789 790 791 792 793 794 795 796
		}

		if (copy > size)
			copy = size;

		i = skb_shinfo(skb)->nr_frags;
		can_coalesce = skb_can_coalesce(skb, i, page, offset);
		if (!can_coalesce && i >= MAX_SKB_FRAGS) {
			tcp_mark_push(tp, skb);
			goto new_segment;
		}
797
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
798
			goto wait_for_memory;
799

L
Linus Torvalds 已提交
800 801 802 803 804 805 806 807 808 809 810
		if (can_coalesce) {
			skb_shinfo(skb)->frags[i - 1].size += copy;
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}

		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
811
		sk_mem_charge(sk, copy);
812
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
813 814
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
815
		skb_shinfo(skb)->gso_segs = 0;
L
Linus Torvalds 已提交
816 817 818 819 820 821 822 823 824

		if (!copied)
			TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;

		copied += copy;
		poffset += copy;
		if (!(psize -= copy))
			goto out;

825
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
826 827 828 829
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
830
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
831
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
832 833 834 835 836 837 838
			tcp_push_one(sk, mss_now);
		continue;

wait_for_sndbuf:
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
		if (copied)
839
			tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
L
Linus Torvalds 已提交
840 841 842 843

		if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
			goto do_error;

I
Ilpo Järvinen 已提交
844
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
845 846 847 848
	}

out:
	if (copied)
849
		tcp_push(sk, flags, mss_now, tp->nonagle);
L
Linus Torvalds 已提交
850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865
	return copied;

do_error:
	if (copied)
		goto out;
out_err:
	return sk_stream_error(sk, flags, err);
}

ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset,
		     size_t size, int flags)
{
	ssize_t res;
	struct sock *sk = sock->sk;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
866
	    !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
L
Linus Torvalds 已提交
867 868 869 870 871 872 873 874 875 876 877 878 879
		return sock_no_sendpage(sock, page, offset, size, flags);

	lock_sock(sk);
	TCP_CHECK_TIMER(sk);
	res = do_tcp_sendpages(sk, &page, offset, size, flags);
	TCP_CHECK_TIMER(sk);
	release_sock(sk);
	return res;
}

#define TCP_PAGE(sk)	(sk->sk_sndmsg_page)
#define TCP_OFF(sk)	(sk->sk_sndmsg_off)

K
Krishna Kumar 已提交
880
static inline int select_size(struct sock *sk, int sg)
L
Linus Torvalds 已提交
881
{
882
	struct tcp_sock *tp = tcp_sk(sk);
883
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
884

K
Krishna Kumar 已提交
885
	if (sg) {
886
		if (sk_can_gso(sk))
887 888 889 890 891 892 893 894 895
			tmp = 0;
		else {
			int pgbreak = SKB_MAX_HEAD(MAX_TCP_HEADER);

			if (tmp >= pgbreak &&
			    tmp <= pgbreak + (MAX_SKB_FRAGS - 1) * PAGE_SIZE)
				tmp = pgbreak;
		}
	}
L
Linus Torvalds 已提交
896 897 898 899

	return tmp;
}

900
int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
L
Linus Torvalds 已提交
901 902
		size_t size)
{
903
	struct sock *sk = sock->sk;
L
Linus Torvalds 已提交
904 905 906 907
	struct iovec *iov;
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
	int iovlen, flags;
908
	int mss_now, size_goal;
K
Krishna Kumar 已提交
909
	int sg, err, copied;
L
Linus Torvalds 已提交
910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925
	long timeo;

	lock_sock(sk);
	TCP_CHECK_TIMER(sk);

	flags = msg->msg_flags;
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

	/* Wait for a connection to finish. */
	if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT))
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_err;

	/* This should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

I
Ilpo Järvinen 已提交
926
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
927 928 929 930 931 932 933 934

	/* Ok commence sending. */
	iovlen = msg->msg_iovlen;
	iov = msg->msg_iov;
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
935
		goto out_err;
L
Linus Torvalds 已提交
936

K
Krishna Kumar 已提交
937 938
	sg = sk->sk_route_caps & NETIF_F_SG;

L
Linus Torvalds 已提交
939 940 941 942 943 944 945
	while (--iovlen >= 0) {
		int seglen = iov->iov_len;
		unsigned char __user *from = iov->iov_base;

		iov++;

		while (seglen > 0) {
946 947
			int copy = 0;
			int max = size_goal;
L
Linus Torvalds 已提交
948

949
			skb = tcp_write_queue_tail(sk);
950 951 952 953 954
			if (tcp_send_head(sk)) {
				if (skb->ip_summed == CHECKSUM_NONE)
					max = mss_now;
				copy = max - skb->len;
			}
L
Linus Torvalds 已提交
955

956
			if (copy <= 0) {
L
Linus Torvalds 已提交
957 958 959 960 961 962 963
new_segment:
				/* Allocate new segment. If the interface is SG,
				 * allocate skb fitting to single page.
				 */
				if (!sk_stream_memory_free(sk))
					goto wait_for_sndbuf;

K
Krishna Kumar 已提交
964 965 966
				skb = sk_stream_alloc_skb(sk,
							  select_size(sk, sg),
							  sk->sk_allocation);
L
Linus Torvalds 已提交
967 968 969 970 971 972
				if (!skb)
					goto wait_for_memory;

				/*
				 * Check whether we can use HW checksum.
				 */
973
				if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
974
					skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
975

976
				skb_entail(sk, skb);
977
				copy = size_goal;
978
				max = size_goal;
L
Linus Torvalds 已提交
979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002
			}

			/* Try to append data to the end of skb. */
			if (copy > seglen)
				copy = seglen;

			/* Where to copy to? */
			if (skb_tailroom(skb) > 0) {
				/* We have some space in skb head. Superb! */
				if (copy > skb_tailroom(skb))
					copy = skb_tailroom(skb);
				if ((err = skb_add_data(skb, from, copy)) != 0)
					goto do_fault;
			} else {
				int merge = 0;
				int i = skb_shinfo(skb)->nr_frags;
				struct page *page = TCP_PAGE(sk);
				int off = TCP_OFF(sk);

				if (skb_can_coalesce(skb, i, page, off) &&
				    off != PAGE_SIZE) {
					/* We can extend the last page
					 * fragment. */
					merge = 1;
K
Krishna Kumar 已提交
1003
				} else if (i == MAX_SKB_FRAGS || !sg) {
L
Linus Torvalds 已提交
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013
					/* Need to add new fragment and cannot
					 * do this because interface is non-SG,
					 * or because all the page slots are
					 * busy. */
					tcp_mark_push(tp, skb);
					goto new_segment;
				} else if (page) {
					if (off == PAGE_SIZE) {
						put_page(page);
						TCP_PAGE(sk) = page = NULL;
1014
						off = 0;
L
Linus Torvalds 已提交
1015
					}
1016
				} else
1017
					off = 0;
1018 1019 1020 1021

				if (copy > PAGE_SIZE - off)
					copy = PAGE_SIZE - off;

1022
				if (!sk_wmem_schedule(sk, copy))
1023
					goto wait_for_memory;
L
Linus Torvalds 已提交
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

				if (!page) {
					/* Allocate new cache page. */
					if (!(page = sk_stream_alloc_page(sk)))
						goto wait_for_memory;
				}

				/* Time to copy data. We are close to
				 * the end! */
				err = skb_copy_to_page(sk, from, skb, page,
						       off, copy);
				if (err) {
					/* If this page was new, give it to the
					 * socket so it does not get leaked.
					 */
					if (!TCP_PAGE(sk)) {
						TCP_PAGE(sk) = page;
						TCP_OFF(sk) = 0;
					}
					goto do_error;
				}

				/* Update the skb. */
				if (merge) {
					skb_shinfo(skb)->frags[i - 1].size +=
									copy;
				} else {
					skb_fill_page_desc(skb, i, page, off, copy);
					if (TCP_PAGE(sk)) {
						get_page(page);
					} else if (off + copy < PAGE_SIZE) {
						get_page(page);
						TCP_PAGE(sk) = page;
					}
				}

				TCP_OFF(sk) = off + copy;
			}

			if (!copied)
				TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;

			tp->write_seq += copy;
			TCP_SKB_CB(skb)->end_seq += copy;
1068
			skb_shinfo(skb)->gso_segs = 0;
L
Linus Torvalds 已提交
1069 1070 1071 1072 1073 1074

			from += copy;
			copied += copy;
			if ((seglen -= copy) == 0 && iovlen == 0)
				goto out;

1075
			if (skb->len < max || (flags & MSG_OOB))
L
Linus Torvalds 已提交
1076 1077 1078 1079
				continue;

			if (forced_push(tp)) {
				tcp_mark_push(tp, skb);
1080
				__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1081
			} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
1082 1083 1084 1085 1086 1087 1088
				tcp_push_one(sk, mss_now);
			continue;

wait_for_sndbuf:
			set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
			if (copied)
1089
				tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
L
Linus Torvalds 已提交
1090 1091 1092 1093

			if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
				goto do_error;

I
Ilpo Järvinen 已提交
1094
			mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1095 1096 1097 1098 1099
		}
	}

out:
	if (copied)
1100
		tcp_push(sk, flags, mss_now, tp->nonagle);
L
Linus Torvalds 已提交
1101 1102 1103 1104 1105 1106
	TCP_CHECK_TIMER(sk);
	release_sock(sk);
	return copied;

do_fault:
	if (!skb->len) {
1107 1108 1109 1110 1111
		tcp_unlink_write_queue(skb, sk);
		/* It is the one place in all of TCP, except connection
		 * reset, where we can be unlinking the send_head.
		 */
		tcp_check_send_head(sk, skb);
1112
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129
	}

do_error:
	if (copied)
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
	TCP_CHECK_TIMER(sk);
	release_sock(sk);
	return err;
}

/*
 *	Handle reading urgent data. BSD has very simple semantics for
 *	this, no blocking and very strange errors 8)
 */

1130
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
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
{
	struct tcp_sock *tp = tcp_sk(sk);

	/* No URG data to read. */
	if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
	    tp->urg_data == TCP_URG_READ)
		return -EINVAL;	/* Yes this is right ! */

	if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
		return -ENOTCONN;

	if (tp->urg_data & TCP_URG_VALID) {
		int err = 0;
		char c = tp->urg_data;

		if (!(flags & MSG_PEEK))
			tp->urg_data = TCP_URG_READ;

		/* Read urgent data. */
		msg->msg_flags |= MSG_OOB;

		if (len > 0) {
			if (!(flags & MSG_TRUNC))
				err = memcpy_toiovec(msg->msg_iov, &c, 1);
			len = 1;
		} else
			msg->msg_flags |= MSG_TRUNC;

		return err ? -EFAULT : len;
	}

	if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
		return 0;

	/* Fixed the recv(..., MSG_OOB) behaviour.  BSD docs and
	 * the available implementations agree in this case:
	 * this call should never block, independent of the
	 * blocking state of the socket.
	 * Mike <pall@rz.uni-karlsruhe.de>
	 */
	return -EAGAIN;
}

/* Clean up the receive buffer for full frames taken by the user,
 * then send an ACK if necessary.  COPIED is the number of bytes
 * tcp_recvmsg has given to the user so far, it speeds up the
 * calculation of whether or not we must ACK for the sake of
 * a window update.
 */
1180
void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1181 1182 1183 1184 1185 1186 1187
{
	struct tcp_sock *tp = tcp_sk(sk);
	int time_to_ack = 0;

#if TCP_DEBUG
	struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);

1188 1189 1190
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
	     KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1191 1192
#endif

1193 1194
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1195 1196
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1197
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1198
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1199
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1200 1201 1202 1203 1204 1205
		    /*
		     * If this read emptied read buffer, we send ACK, if
		     * connection is not bidirectional, user drained
		     * receive buffer and there was a small segment
		     * in queue.
		     */
1206 1207 1208 1209 1210
		    (copied > 0 &&
		     ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
		      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
		       !icsk->icsk_ack.pingpong)) &&
		      !atomic_read(&sk->sk_rmem_alloc)))
L
Linus Torvalds 已提交
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
			time_to_ack = 1;
	}

	/* We send an ACK if we can now advertise a non-zero window
	 * which has been raised "significantly".
	 *
	 * Even if window raised up to infinity, do not send window open ACK
	 * in states, where we will not receive more. It is useless.
	 */
	if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
		__u32 rcv_window_now = tcp_receive_window(tp);

		/* Optimize, __tcp_select_window() is not cheap. */
		if (2*rcv_window_now <= tp->window_clamp) {
			__u32 new_window = __tcp_select_window(sk);

			/* Send ACK now, if this read freed lots of space
			 * in our buffer. Certainly, new_window is new window.
			 * We can advertise it now, if it is not less than current one.
			 * "Lots" means "at least twice" here.
			 */
			if (new_window && new_window >= 2 * rcv_window_now)
				time_to_ack = 1;
		}
	}
	if (time_to_ack)
		tcp_send_ack(sk);
}

static void tcp_prequeue_process(struct sock *sk)
{
	struct sk_buff *skb;
	struct tcp_sock *tp = tcp_sk(sk);

1245
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1246 1247 1248 1249 1250

	/* RX process wants to run with disabled BHs, though it is not
	 * necessary */
	local_bh_disable();
	while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
P
Peter Zijlstra 已提交
1251
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1252 1253 1254 1255 1256 1257
	local_bh_enable();

	/* Clear memory counter. */
	tp->ucopy.memory = 0;
}

1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290
#ifdef CONFIG_NET_DMA
static void tcp_service_net_dma(struct sock *sk, bool wait)
{
	dma_cookie_t done, used;
	dma_cookie_t last_issued;
	struct tcp_sock *tp = tcp_sk(sk);

	if (!tp->ucopy.dma_chan)
		return;

	last_issued = tp->ucopy.dma_cookie;
	dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);

	do {
		if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
					      last_issued, &done,
					      &used) == DMA_SUCCESS) {
			/* Safe to free early-copied skbs now */
			__skb_queue_purge(&sk->sk_async_wait_queue);
			break;
		} else {
			struct sk_buff *skb;
			while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
			       (dma_async_is_complete(skb->dma_cookie, done,
						      used) == DMA_SUCCESS)) {
				__skb_dequeue(&sk->sk_async_wait_queue);
				kfree_skb(skb);
			}
		}
	} while (wait);
}
#endif

L
Linus Torvalds 已提交
1291 1292 1293 1294 1295 1296 1297
static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
{
	struct sk_buff *skb;
	u32 offset;

	skb_queue_walk(&sk->sk_receive_queue, skb) {
		offset = seq - TCP_SKB_CB(skb)->seq;
1298
		if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1299
			offset--;
1300
		if (offset < skb->len || tcp_hdr(skb)->fin) {
L
Linus Torvalds 已提交
1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331
			*off = offset;
			return skb;
		}
	}
	return NULL;
}

/*
 * This routine provides an alternative to tcp_recvmsg() for routines
 * that would like to handle copying from skbuffs directly in 'sendfile'
 * fashion.
 * Note:
 *	- It is assumed that the socket was locked by the caller.
 *	- The routine does not block.
 *	- At present, there is no support for reading OOB data
 *	  or for 'peeking' the socket using this routine
 *	  (although both would be easy to implement).
 */
int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
		  sk_read_actor_t recv_actor)
{
	struct sk_buff *skb;
	struct tcp_sock *tp = tcp_sk(sk);
	u32 seq = tp->copied_seq;
	u32 offset;
	int copied = 0;

	if (sk->sk_state == TCP_LISTEN)
		return -ENOTCONN;
	while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
		if (offset < skb->len) {
1332 1333
			int used;
			size_t len;
L
Linus Torvalds 已提交
1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344

			len = skb->len - offset;
			/* Stop reading if we hit a patch of urgent data */
			if (tp->urg_data) {
				u32 urg_offset = tp->urg_seq - seq;
				if (urg_offset < len)
					len = urg_offset;
				if (!len)
					break;
			}
			used = recv_actor(desc, skb, offset, len);
1345 1346 1347 1348 1349
			if (used < 0) {
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1350 1351 1352 1353
				seq += used;
				copied += used;
				offset += used;
			}
1354 1355 1356 1357 1358 1359 1360 1361
			/*
			 * If recv_actor drops the lock (e.g. TCP splice
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
			skb = tcp_recv_skb(sk, seq-1, &offset);
			if (!skb || (offset+1 != skb->len))
L
Linus Torvalds 已提交
1362 1363
				break;
		}
1364
		if (tcp_hdr(skb)->fin) {
1365
			sk_eat_skb(sk, skb, 0);
L
Linus Torvalds 已提交
1366 1367 1368
			++seq;
			break;
		}
1369
		sk_eat_skb(sk, skb, 0);
L
Linus Torvalds 已提交
1370 1371
		if (!desc->count)
			break;
1372
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1373 1374 1375 1376 1377 1378
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1379
	if (copied > 0)
1380
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
	return copied;
}

/*
 *	This routine copies from a sock struct into the user buffer.
 *
 *	Technical note: in 2.3 we work on _locked_ socket, so that
 *	tricks with *seq access order and skb->users are not required.
 *	Probably, code can be easily improved even more.
 */

int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len, int nonblock, int flags, int *addr_len)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int copied = 0;
	u32 peek_seq;
	u32 *seq;
	unsigned long used;
	int err;
	int target;		/* Read at least this many bytes */
	long timeo;
	struct task_struct *user_recv = NULL;
C
Chris Leech 已提交
1404
	int copied_early = 0;
1405
	struct sk_buff *skb;
I
Ilpo Järvinen 已提交
1406
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429

	lock_sock(sk);

	TCP_CHECK_TIMER(sk);

	err = -ENOTCONN;
	if (sk->sk_state == TCP_LISTEN)
		goto out;

	timeo = sock_rcvtimeo(sk, nonblock);

	/* Urgent data needs to be handled specially. */
	if (flags & MSG_OOB)
		goto recv_urg;

	seq = &tp->copied_seq;
	if (flags & MSG_PEEK) {
		peek_seq = tp->copied_seq;
		seq = &peek_seq;
	}

	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);

C
Chris Leech 已提交
1430 1431 1432
#ifdef CONFIG_NET_DMA
	tp->ucopy.dma_chan = NULL;
	preempt_disable();
1433
	skb = skb_peek_tail(&sk->sk_receive_queue);
A
Andrew Morton 已提交
1434 1435 1436 1437 1438 1439 1440 1441
	{
		int available = 0;

		if (skb)
			available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
		if ((available < target) &&
		    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
		    !sysctl_tcp_low_latency &&
1442
		    dma_find_channel(DMA_MEMCPY)) {
A
Andrew Morton 已提交
1443 1444 1445 1446 1447 1448 1449
			preempt_enable_no_resched();
			tp->ucopy.pinned_list =
					dma_pin_iovec_pages(msg->msg_iov, len);
		} else {
			preempt_enable_no_resched();
		}
	}
C
Chris Leech 已提交
1450 1451
#endif

L
Linus Torvalds 已提交
1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466
	do {
		u32 offset;

		/* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
		if (tp->urg_data && tp->urg_seq == *seq) {
			if (copied)
				break;
			if (signal_pending(current)) {
				copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
				break;
			}
		}

		/* Next get a buffer. */

1467
		skb_queue_walk(&sk->sk_receive_queue, skb) {
L
Linus Torvalds 已提交
1468 1469 1470
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1471 1472 1473 1474 1475
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
			     KERN_INFO "recvmsg bug: copied %X "
				       "seq %X rcvnxt %X fl %X\n", *seq,
				       TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
				       flags))
L
Linus Torvalds 已提交
1476
				break;
1477

L
Linus Torvalds 已提交
1478
			offset = *seq - TCP_SKB_CB(skb)->seq;
1479
			if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1480 1481 1482
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1483
			if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1484
				goto found_fin_ok;
1485
			WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1486 1487 1488
					"copied %X seq %X rcvnxt %X fl %X\n",
					*seq, TCP_SKB_CB(skb)->seq,
					tp->rcv_nxt, flags);
1489
		}
L
Linus Torvalds 已提交
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500

		/* Well, if we have backlog, try to process it now yet. */

		if (copied >= target && !sk->sk_backlog.tail)
			break;

		if (copied) {
			if (sk->sk_err ||
			    sk->sk_state == TCP_CLOSE ||
			    (sk->sk_shutdown & RCV_SHUTDOWN) ||
			    !timeo ||
1501
			    signal_pending(current))
L
Linus Torvalds 已提交
1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536
				break;
		} else {
			if (sock_flag(sk, SOCK_DONE))
				break;

			if (sk->sk_err) {
				copied = sock_error(sk);
				break;
			}

			if (sk->sk_shutdown & RCV_SHUTDOWN)
				break;

			if (sk->sk_state == TCP_CLOSE) {
				if (!sock_flag(sk, SOCK_DONE)) {
					/* This occurs when user tries to read
					 * from never connected socket.
					 */
					copied = -ENOTCONN;
					break;
				}
				break;
			}

			if (!timeo) {
				copied = -EAGAIN;
				break;
			}

			if (signal_pending(current)) {
				copied = sock_intr_errno(timeo);
				break;
			}
		}

1537
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1538

1539
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1540 1541 1542 1543 1544 1545 1546 1547 1548
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
				tp->ucopy.iov = msg->msg_iov;
			}

			tp->ucopy.len = len;

1549 1550
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 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 1577

			/* Ugly... If prequeue is not empty, we have to
			 * process it before releasing socket, otherwise
			 * order will be broken at second iteration.
			 * More elegant solution is required!!!
			 *
			 * Look: we have the following (pseudo)queues:
			 *
			 * 1. packets in flight
			 * 2. backlog
			 * 3. prequeue
			 * 4. receive_queue
			 *
			 * Each queue can be processed only if the next ones
			 * are empty. At this point we have empty receive_queue.
			 * But prequeue _can_ be not empty after 2nd iteration,
			 * when we jumped to start of loop because backlog
			 * processing added something to receive_queue.
			 * We cannot release_sock(), because backlog contains
			 * packets arrived _after_ prequeued ones.
			 *
			 * Shortly, algorithm is clear --- to process all
			 * the queues in order. We could make it more directly,
			 * requeueing packets from backlog to prequeue, if
			 * is not empty. It is more elegant, but eats cycles,
			 * unfortunately.
			 */
1578
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1579 1580 1581 1582 1583
				goto do_prequeue;

			/* __ Set realtime policy in scheduler __ */
		}

1584 1585 1586 1587
#ifdef CONFIG_NET_DMA
		if (tp->ucopy.dma_chan)
			dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
#endif
L
Linus Torvalds 已提交
1588 1589 1590 1591 1592 1593 1594
		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
		} else
			sk_wait_data(sk, &timeo);

C
Chris Leech 已提交
1595
#ifdef CONFIG_NET_DMA
1596
		tcp_service_net_dma(sk, false);  /* Don't block */
C
Chris Leech 已提交
1597 1598 1599
		tp->ucopy.wakeup = 0;
#endif

L
Linus Torvalds 已提交
1600 1601 1602 1603 1604 1605
		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

			if ((chunk = len - tp->ucopy.len) != 0) {
1606
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1607 1608 1609 1610 1611
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1612
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1613 1614 1615 1616
do_prequeue:
				tcp_prequeue_process(sk);

				if ((chunk = len - tp->ucopy.len) != 0) {
1617
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1618 1619 1620 1621 1622
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1623 1624
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
L
Linus Torvalds 已提交
1625 1626
			if (net_ratelimit())
				printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1627
				       current->comm, task_pid_nr(current));
L
Linus Torvalds 已提交
1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644
			peek_seq = tp->copied_seq;
		}
		continue;

	found_ok_skb:
		/* Ok so how much can we use? */
		used = skb->len - offset;
		if (len < used)
			used = len;

		/* Do we have urgent data here? */
		if (tp->urg_data) {
			u32 urg_offset = tp->urg_seq - *seq;
			if (urg_offset < used) {
				if (!urg_offset) {
					if (!sock_flag(sk, SOCK_URGINLINE)) {
						++*seq;
I
Ilpo Järvinen 已提交
1645
						urg_hole++;
L
Linus Torvalds 已提交
1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
C
Chris Leech 已提交
1657 1658
#ifdef CONFIG_NET_DMA
			if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1659
				tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
C
Chris Leech 已提交
1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675

			if (tp->ucopy.dma_chan) {
				tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
					tp->ucopy.dma_chan, skb, offset,
					msg->msg_iov, used,
					tp->ucopy.pinned_list);

				if (tp->ucopy.dma_cookie < 0) {

					printk(KERN_ALERT "dma_cookie < 0\n");

					/* Exception. Bailout! */
					if (!copied)
						copied = -EFAULT;
					break;
				}
1676 1677 1678

				dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);

C
Chris Leech 已提交
1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692
				if ((offset + used) == skb->len)
					copied_early = 1;

			} else
#endif
			{
				err = skb_copy_datagram_iovec(skb, offset,
						msg->msg_iov, used);
				if (err) {
					/* Exception. Bailout! */
					if (!copied)
						copied = -EFAULT;
					break;
				}
L
Linus Torvalds 已提交
1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704
			}
		}

		*seq += used;
		copied += used;
		len -= used;

		tcp_rcv_space_adjust(sk);

skip_copy:
		if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
			tp->urg_data = 0;
1705
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1706 1707 1708 1709
		}
		if (used + offset < skb->len)
			continue;

1710
		if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1711
			goto found_fin_ok;
C
Chris Leech 已提交
1712 1713 1714 1715
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
			copied_early = 0;
		}
L
Linus Torvalds 已提交
1716 1717 1718 1719 1720
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
C
Chris Leech 已提交
1721 1722 1723 1724
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
			copied_early = 0;
		}
L
Linus Torvalds 已提交
1725 1726 1727 1728
		break;
	} while (len > 0);

	if (user_recv) {
1729
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1730 1731 1732 1733 1734 1735 1736
			int chunk;

			tp->ucopy.len = copied > 0 ? len : 0;

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1737
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1738 1739 1740 1741 1742 1743 1744 1745 1746
				len -= chunk;
				copied += chunk;
			}
		}

		tp->ucopy.task = NULL;
		tp->ucopy.len = 0;
	}

C
Chris Leech 已提交
1747
#ifdef CONFIG_NET_DMA
1748 1749
	tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
	tp->ucopy.dma_chan = NULL;
C
Chris Leech 已提交
1750 1751 1752 1753 1754 1755 1756

	if (tp->ucopy.pinned_list) {
		dma_unpin_iovec_pages(tp->ucopy.pinned_list);
		tp->ucopy.pinned_list = NULL;
	}
#endif

L
Linus Torvalds 已提交
1757 1758 1759 1760 1761
	/* According to UNIX98, msg_name/msg_namelen are ignored
	 * on connected socket. I was just happy when found this 8) --ANK
	 */

	/* Clean up data we have read: This will do ACK frames. */
1762
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773

	TCP_CHECK_TIMER(sk);
	release_sock(sk);
	return copied;

out:
	TCP_CHECK_TIMER(sk);
	release_sock(sk);
	return err;

recv_urg:
1774
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1775 1776 1777
	goto out;
}

I
Ilpo Järvinen 已提交
1778 1779 1780 1781 1782 1783 1784
void tcp_set_state(struct sock *sk, int state)
{
	int oldstate = sk->sk_state;

	switch (state) {
	case TCP_ESTABLISHED:
		if (oldstate != TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1785
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1786 1787 1788 1789
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1790
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1791 1792 1793 1794

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1795
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1796 1797
		/* fall through */
	default:
1798
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1799
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1800 1801 1802 1803 1804 1805 1806 1807
	}

	/* Change state AFTER socket is unhashed to avoid closed
	 * socket sitting in hash tables.
	 */
	sk->sk_state = state;

#ifdef STATE_TRACE
1808
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1809 1810 1811 1812
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1813 1814 1815 1816 1817 1818 1819
/*
 *	State processing on a close. This implements the state shift for
 *	sending our FIN frame. Note that we only send a FIN for some
 *	states. A shutdown() may have already sent the FIN, or we may be
 *	closed.
 */

1820
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847
  /* current state:        new state:      action:	*/
  /* (Invalid)		*/ TCP_CLOSE,
  /* TCP_ESTABLISHED	*/ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  /* TCP_SYN_SENT	*/ TCP_CLOSE,
  /* TCP_SYN_RECV	*/ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  /* TCP_FIN_WAIT1	*/ TCP_FIN_WAIT1,
  /* TCP_FIN_WAIT2	*/ TCP_FIN_WAIT2,
  /* TCP_TIME_WAIT	*/ TCP_CLOSE,
  /* TCP_CLOSE		*/ TCP_CLOSE,
  /* TCP_CLOSE_WAIT	*/ TCP_LAST_ACK  | TCP_ACTION_FIN,
  /* TCP_LAST_ACK	*/ TCP_LAST_ACK,
  /* TCP_LISTEN		*/ TCP_CLOSE,
  /* TCP_CLOSING	*/ TCP_CLOSING,
};

static int tcp_close_state(struct sock *sk)
{
	int next = (int)new_state[sk->sk_state];
	int ns = next & TCP_STATE_MASK;

	tcp_set_state(sk, ns);

	return next & TCP_ACTION_FIN;
}

/*
 *	Shutdown the sending side of a connection. Much like close except
1848
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873
 */

void tcp_shutdown(struct sock *sk, int how)
{
	/*	We need to grab some memory, and put together a FIN,
	 *	and then put it into the queue to be sent.
	 *		Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
	 */
	if (!(how & SEND_SHUTDOWN))
		return;

	/* If we've already sent a FIN, or it's a closed state, skip this. */
	if ((1 << sk->sk_state) &
	    (TCPF_ESTABLISHED | TCPF_SYN_SENT |
	     TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
		/* Clear out any half completed packets.  FIN if needed. */
		if (tcp_close_state(sk))
			tcp_send_fin(sk);
	}
}

void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
1874
	int state;
L
Linus Torvalds 已提交
1875 1876 1877 1878 1879 1880 1881 1882

	lock_sock(sk);
	sk->sk_shutdown = SHUTDOWN_MASK;

	if (sk->sk_state == TCP_LISTEN) {
		tcp_set_state(sk, TCP_CLOSE);

		/* Special case. */
1883
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
1884 1885 1886 1887 1888 1889 1890 1891 1892 1893

		goto adjudge_to_death;
	}

	/*  We need to flush the recv. buffs.  We do this only on the
	 *  descriptor close, not protocol-sourced closes, because the
	 *  reader process may not have drained the data yet!
	 */
	while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
		u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
1894
			  tcp_hdr(skb)->fin;
L
Linus Torvalds 已提交
1895 1896 1897 1898
		data_was_unread += len;
		__kfree_skb(skb);
	}

1899
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
1900

1901 1902 1903 1904 1905 1906
	/* As outlined in RFC 2525, section 2.17, we send a RST here because
	 * data was lost. To witness the awful effects of the old behavior of
	 * always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
	 * GET in an FTP client, suspend the process, wait for the client to
	 * advertise a zero window, then kill -9 the FTP client, wheee...
	 * Note: timeout is always zero in such a case.
L
Linus Torvalds 已提交
1907 1908 1909
	 */
	if (data_was_unread) {
		/* Unread data was tossed, zap the connection. */
1910
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
1911
		tcp_set_state(sk, TCP_CLOSE);
1912
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
1913 1914 1915
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
1916
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948
	} else if (tcp_close_state(sk)) {
		/* We FIN if the application ate all the data before
		 * zapping the connection.
		 */

		/* RED-PEN. Formally speaking, we have broken TCP state
		 * machine. State transitions:
		 *
		 * TCP_ESTABLISHED -> TCP_FIN_WAIT1
		 * TCP_SYN_RECV	-> TCP_FIN_WAIT1 (forget it, it's impossible)
		 * TCP_CLOSE_WAIT -> TCP_LAST_ACK
		 *
		 * are legal only when FIN has been sent (i.e. in window),
		 * rather than queued out of window. Purists blame.
		 *
		 * F.e. "RFC state" is ESTABLISHED,
		 * if Linux state is FIN-WAIT-1, but FIN is still not sent.
		 *
		 * The visible declinations are that sometimes
		 * we enter time-wait state, when it is not required really
		 * (harmless), do not send active resets, when they are
		 * required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
		 * they look as CLOSING or LAST_ACK for Linux)
		 * Probably, I missed some more holelets.
		 * 						--ANK
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
1949 1950 1951 1952
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
1953 1954 1955 1956 1957 1958 1959 1960 1961
	/* It is the last release_sock in its life. It will remove backlog. */
	release_sock(sk);


	/* Now socket is owned by kernel and we acquire BH lock
	   to finish close. No need to check for user refs.
	 */
	local_bh_disable();
	bh_lock_sock(sk);
1962
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
1963

H
Herbert Xu 已提交
1964 1965
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
1966 1967 1968
	/* Have we already been destroyed by a softirq or backlog? */
	if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
		goto out;
L
Linus Torvalds 已提交
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988

	/*	This is a (useful) BSD violating of the RFC. There is a
	 *	problem with TCP as specified in that the other end could
	 *	keep a socket open forever with no application left this end.
	 *	We use a 3 minute timeout (about the same as BSD) then kill
	 *	our end. If they send after that then tough - BUT: long enough
	 *	that we won't make the old 4*rto = almost no time - whoops
	 *	reset mistake.
	 *
	 *	Nope, it was not mistake. It is really desired behaviour
	 *	f.e. on http servers, when such sockets are useless, but
	 *	consume significant resources. Let's do it with special
	 *	linger2	option.					--ANK
	 */

	if (sk->sk_state == TCP_FIN_WAIT2) {
		struct tcp_sock *tp = tcp_sk(sk);
		if (tp->linger2 < 0) {
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
1989 1990
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
1991
		} else {
1992
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
1993 1994

			if (tmo > TCP_TIMEWAIT_LEN) {
1995 1996
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
1997 1998 1999 2000 2001 2002 2003
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2004 2005 2006
		int orphan_count = percpu_counter_read_positive(
						sk->sk_prot->orphan_count);

2007
		sk_mem_reclaim(sk);
2008
		if (tcp_too_many_orphans(sk, orphan_count)) {
L
Linus Torvalds 已提交
2009 2010 2011 2012 2013
			if (net_ratelimit())
				printk(KERN_INFO "TCP: too many of orphaned "
				       "sockets\n");
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2014 2015
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2016 2017 2018 2019
		}
	}

	if (sk->sk_state == TCP_CLOSE)
2020
		inet_csk_destroy_sock(sk);
L
Linus Torvalds 已提交
2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040
	/* Otherwise, socket is reprieved until protocol close. */

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

/* These states need RST on ABORT according to RFC793 */

static inline int tcp_need_reset(int state)
{
	return (1 << state) &
	       (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
		TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
}

int tcp_disconnect(struct sock *sk, int flags)
{
	struct inet_sock *inet = inet_sk(sk);
2041
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2042 2043 2044 2045 2046 2047 2048 2049 2050
	struct tcp_sock *tp = tcp_sk(sk);
	int err = 0;
	int old_state = sk->sk_state;

	if (old_state != TCP_CLOSE)
		tcp_set_state(sk, TCP_CLOSE);

	/* ABORT function of RFC793 */
	if (old_state == TCP_LISTEN) {
2051
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2052 2053 2054
	} else if (tcp_need_reset(old_state) ||
		   (tp->snd_nxt != tp->write_seq &&
		    (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
S
Stephen Hemminger 已提交
2055
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2056 2057 2058 2059 2060 2061 2062 2063 2064
		 * states
		 */
		tcp_send_active_reset(sk, gfp_any());
		sk->sk_err = ECONNRESET;
	} else if (old_state == TCP_SYN_SENT)
		sk->sk_err = ECONNRESET;

	tcp_clear_xmit_timers(sk);
	__skb_queue_purge(&sk->sk_receive_queue);
2065
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2066
	__skb_queue_purge(&tp->out_of_order_queue);
C
Chris Leech 已提交
2067 2068 2069
#ifdef CONFIG_NET_DMA
	__skb_queue_purge(&sk->sk_async_wait_queue);
#endif
L
Linus Torvalds 已提交
2070

E
Eric Dumazet 已提交
2071
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2072 2073 2074 2075 2076 2077 2078 2079 2080

	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
		inet_reset_saddr(sk);

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
	tp->srtt = 0;
	if ((tp->write_seq += tp->max_window + 2) == 0)
		tp->write_seq = 1;
2081
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2082
	tp->snd_cwnd = 2;
2083
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2084
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2085
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2086
	tp->snd_cwnd_cnt = 0;
2087
	tp->bytes_acked = 0;
2088
	tp->window_clamp = 0;
2089
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2090
	tcp_clear_retrans(tp);
2091
	inet_csk_delack_init(sk);
2092
	tcp_init_send_head(sk);
2093
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2094 2095
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2096
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2097 2098 2099 2100 2101 2102 2103 2104

	sk->sk_error_report(sk);
	return err;
}

/*
 *	Socket option code for TCP.
 */
2105
static int do_tcp_setsockopt(struct sock *sk, int level,
2106
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2107 2108
{
	struct tcp_sock *tp = tcp_sk(sk);
2109
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2110 2111 2112
	int val;
	int err = 0;

2113 2114 2115
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2116 2117 2118 2119 2120 2121
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2122
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2123 2124 2125 2126 2127
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2128
		err = tcp_set_congestion_control(sk, name);
2129 2130 2131
		release_sock(sk);
		return err;
	}
2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 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 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217
	case TCP_COOKIE_TRANSACTIONS: {
		struct tcp_cookie_transactions ctd;
		struct tcp_cookie_values *cvp = NULL;

		if (sizeof(ctd) > optlen)
			return -EINVAL;
		if (copy_from_user(&ctd, optval, sizeof(ctd)))
			return -EFAULT;

		if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
		    ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
			return -EINVAL;

		if (ctd.tcpct_cookie_desired == 0) {
			/* default to global value */
		} else if ((0x1 & ctd.tcpct_cookie_desired) ||
			   ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
			   ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
			return -EINVAL;
		}

		if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
			/* Supercedes all other values */
			lock_sock(sk);
			if (tp->cookie_values != NULL) {
				kref_put(&tp->cookie_values->kref,
					 tcp_cookie_values_release);
				tp->cookie_values = NULL;
			}
			tp->rx_opt.cookie_in_always = 0; /* false */
			tp->rx_opt.cookie_out_never = 1; /* true */
			release_sock(sk);
			return err;
		}

		/* Allocate ancillary memory before locking.
		 */
		if (ctd.tcpct_used > 0 ||
		    (tp->cookie_values == NULL &&
		     (sysctl_tcp_cookie_size > 0 ||
		      ctd.tcpct_cookie_desired > 0 ||
		      ctd.tcpct_s_data_desired > 0))) {
			cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
				      GFP_KERNEL);
			if (cvp == NULL)
				return -ENOMEM;
		}
		lock_sock(sk);
		tp->rx_opt.cookie_in_always =
			(TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
		tp->rx_opt.cookie_out_never = 0; /* false */

		if (tp->cookie_values != NULL) {
			if (cvp != NULL) {
				/* Changed values are recorded by a changed
				 * pointer, ensuring the cookie will differ,
				 * without separately hashing each value later.
				 */
				kref_put(&tp->cookie_values->kref,
					 tcp_cookie_values_release);
				kref_init(&cvp->kref);
				tp->cookie_values = cvp;
			} else {
				cvp = tp->cookie_values;
			}
		}
		if (cvp != NULL) {
			cvp->cookie_desired = ctd.tcpct_cookie_desired;

			if (ctd.tcpct_used > 0) {
				memcpy(cvp->s_data_payload, ctd.tcpct_value,
				       ctd.tcpct_used);
				cvp->s_data_desired = ctd.tcpct_used;
				cvp->s_data_constant = 1; /* true */
			} else {
				/* No constant payload data. */
				cvp->s_data_desired = ctd.tcpct_s_data_desired;
				cvp->s_data_constant = 0; /* false */
			}
		}
		release_sock(sk);
		return err;
	}
	default:
		/* fallthru */
		break;
2218
	}
2219

L
Linus Torvalds 已提交
2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250
	if (optlen < sizeof(int))
		return -EINVAL;

	if (get_user(val, (int __user *)optval))
		return -EFAULT;

	lock_sock(sk);

	switch (optname) {
	case TCP_MAXSEG:
		/* Values greater than interface MTU won't take effect. However
		 * at the point when this call is done we typically don't yet
		 * know which interface is going to be used */
		if (val < 8 || val > MAX_TCP_WINDOW) {
			err = -EINVAL;
			break;
		}
		tp->rx_opt.user_mss = val;
		break;

	case TCP_NODELAY:
		if (val) {
			/* TCP_NODELAY is weaker than TCP_CORK, so that
			 * this option on corked socket is remembered, but
			 * it is not activated until cork is cleared.
			 *
			 * However, when TCP_NODELAY is set we make
			 * an explicit push, which overrides even TCP_CORK
			 * for currently queued segments.
			 */
			tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2251
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2252 2253 2254 2255 2256
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2257 2258 2259 2260 2261 2262 2263
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2264 2265 2266 2267 2268 2269 2270
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_dupack = val;
		break;

L
Linus Torvalds 已提交
2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288
	case TCP_CORK:
		/* When set indicates to always queue non-full frames.
		 * Later the user clears this option and we transmit
		 * any pending partial frames in the queue.  This is
		 * meant to be used alongside sendfile() to get properly
		 * filled frames when the user (for example) must write
		 * out headers with a write() call first and then use
		 * sendfile to send out the data parts.
		 *
		 * TCP_CORK can be set together with TCP_NODELAY and it is
		 * stronger than TCP_NODELAY.
		 */
		if (val) {
			tp->nonagle |= TCP_NAGLE_CORK;
		} else {
			tp->nonagle &= ~TCP_NAGLE_CORK;
			if (tp->nonagle&TCP_NAGLE_OFF)
				tp->nonagle |= TCP_NAGLE_PUSH;
2289
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300
		}
		break;

	case TCP_KEEPIDLE:
		if (val < 1 || val > MAX_TCP_KEEPIDLE)
			err = -EINVAL;
		else {
			tp->keepalive_time = val * HZ;
			if (sock_flag(sk, SOCK_KEEPOPEN) &&
			    !((1 << sk->sk_state) &
			      (TCPF_CLOSE | TCPF_LISTEN))) {
2301
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2302 2303 2304 2305
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2306
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325
			}
		}
		break;
	case TCP_KEEPINTVL:
		if (val < 1 || val > MAX_TCP_KEEPINTVL)
			err = -EINVAL;
		else
			tp->keepalive_intvl = val * HZ;
		break;
	case TCP_KEEPCNT:
		if (val < 1 || val > MAX_TCP_KEEPCNT)
			err = -EINVAL;
		else
			tp->keepalive_probes = val;
		break;
	case TCP_SYNCNT:
		if (val < 1 || val > MAX_TCP_SYNCNT)
			err = -EINVAL;
		else
2326
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338
		break;

	case TCP_LINGER2:
		if (val < 0)
			tp->linger2 = -1;
		else if (val > sysctl_tcp_fin_timeout / HZ)
			tp->linger2 = 0;
		else
			tp->linger2 = val * HZ;
		break;

	case TCP_DEFER_ACCEPT:
2339 2340 2341 2342
		/* Translate value in seconds to number of retransmits */
		icsk->icsk_accept_queue.rskq_defer_accept =
			secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
					TCP_RTO_MAX / HZ);
L
Linus Torvalds 已提交
2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358
		break;

	case TCP_WINDOW_CLAMP:
		if (!val) {
			if (sk->sk_state != TCP_CLOSE) {
				err = -EINVAL;
				break;
			}
			tp->window_clamp = 0;
		} else
			tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
						SOCK_MIN_RCVBUF / 2 : val;
		break;

	case TCP_QUICKACK:
		if (!val) {
2359
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2360
		} else {
2361
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2362 2363
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2364 2365
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2366
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2367
				if (!(val & 1))
2368
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2369 2370 2371 2372
			}
		}
		break;

2373 2374 2375 2376 2377 2378 2379
#ifdef CONFIG_TCP_MD5SIG
	case TCP_MD5SIG:
		/* Read the IP->Key mappings from userspace */
		err = tp->af_specific->md5_parse(sk, optval, optlen);
		break;
#endif

L
Linus Torvalds 已提交
2380 2381 2382
	default:
		err = -ENOPROTOOPT;
		break;
2383 2384
	}

L
Linus Torvalds 已提交
2385 2386 2387 2388
	release_sock(sk);
	return err;
}

2389
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2390
		   unsigned int optlen)
2391 2392 2393 2394 2395 2396 2397 2398 2399 2400
{
	struct inet_connection_sock *icsk = inet_csk(sk);

	if (level != SOL_TCP)
		return icsk->icsk_af_ops->setsockopt(sk, level, optname,
						     optval, optlen);
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
2401
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2402
			  char __user *optval, unsigned int optlen)
2403
{
2404 2405 2406
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2407 2408
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2409 2410

EXPORT_SYMBOL(compat_tcp_setsockopt);
2411 2412
#endif

L
Linus Torvalds 已提交
2413 2414 2415 2416
/* Return information about state of tcp endpoint in API format. */
void tcp_get_info(struct sock *sk, struct tcp_info *info)
{
	struct tcp_sock *tp = tcp_sk(sk);
2417
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2418 2419 2420 2421 2422
	u32 now = tcp_time_stamp;

	memset(info, 0, sizeof(*info));

	info->tcpi_state = sk->sk_state;
2423
	info->tcpi_ca_state = icsk->icsk_ca_state;
2424
	info->tcpi_retransmits = icsk->icsk_retransmits;
2425
	info->tcpi_probes = icsk->icsk_probes_out;
2426
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2427 2428 2429

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2430
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2431 2432 2433 2434 2435
		info->tcpi_options |= TCPI_OPT_SACK;
	if (tp->rx_opt.wscale_ok) {
		info->tcpi_options |= TCPI_OPT_WSCALE;
		info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
		info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
2436
	}
L
Linus Torvalds 已提交
2437 2438 2439 2440

	if (tp->ecn_flags&TCP_ECN_OK)
		info->tcpi_options |= TCPI_OPT_ECN;

2441 2442
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2443
	info->tcpi_snd_mss = tp->mss_cache;
2444
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2445

2446 2447 2448 2449 2450 2451 2452
	if (sk->sk_state == TCP_LISTEN) {
		info->tcpi_unacked = sk->sk_ack_backlog;
		info->tcpi_sacked = sk->sk_max_ack_backlog;
	} else {
		info->tcpi_unacked = tp->packets_out;
		info->tcpi_sacked = tp->sacked_out;
	}
L
Linus Torvalds 已提交
2453 2454 2455 2456 2457
	info->tcpi_lost = tp->lost_out;
	info->tcpi_retrans = tp->retrans_out;
	info->tcpi_fackets = tp->fackets_out;

	info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
2458
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2459 2460
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2461
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
	info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
	info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
	info->tcpi_snd_ssthresh = tp->snd_ssthresh;
	info->tcpi_snd_cwnd = tp->snd_cwnd;
	info->tcpi_advmss = tp->advmss;
	info->tcpi_reordering = tp->reordering;

	info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
	info->tcpi_rcv_space = tp->rcvq_space.space;

	info->tcpi_total_retrans = tp->total_retrans;
}

EXPORT_SYMBOL_GPL(tcp_get_info);

2478 2479
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2480
{
2481
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494
	struct tcp_sock *tp = tcp_sk(sk);
	int val, len;

	if (get_user(len, optlen))
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));

	if (len < 0)
		return -EINVAL;

	switch (optname) {
	case TCP_MAXSEG:
2495
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2496 2497 2498 2499 2500 2501 2502 2503 2504 2505
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
		break;
	case TCP_NODELAY:
		val = !!(tp->nonagle&TCP_NAGLE_OFF);
		break;
	case TCP_CORK:
		val = !!(tp->nonagle&TCP_NAGLE_CORK);
		break;
	case TCP_KEEPIDLE:
E
Eric Dumazet 已提交
2506
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2507 2508
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2509
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2510 2511
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2512
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2513 2514
		break;
	case TCP_SYNCNT:
2515
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2516 2517 2518 2519 2520 2521 2522
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2523 2524
		val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
				      TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
L
Linus Torvalds 已提交
2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544
		break;
	case TCP_WINDOW_CLAMP:
		val = tp->window_clamp;
		break;
	case TCP_INFO: {
		struct tcp_info info;

		if (get_user(len, optlen))
			return -EFAULT;

		tcp_get_info(sk, &info);

		len = min_t(unsigned int, len, sizeof(info));
		if (put_user(len, optlen))
			return -EFAULT;
		if (copy_to_user(optval, &info, len))
			return -EFAULT;
		return 0;
	}
	case TCP_QUICKACK:
2545
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2546
		break;
2547 2548 2549 2550 2551 2552 2553

	case TCP_CONGESTION:
		if (get_user(len, optlen))
			return -EFAULT;
		len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
		if (put_user(len, optlen))
			return -EFAULT;
2554
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2555 2556
			return -EFAULT;
		return 0;
2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592

	case TCP_COOKIE_TRANSACTIONS: {
		struct tcp_cookie_transactions ctd;
		struct tcp_cookie_values *cvp = tp->cookie_values;

		if (get_user(len, optlen))
			return -EFAULT;
		if (len < sizeof(ctd))
			return -EINVAL;

		memset(&ctd, 0, sizeof(ctd));
		ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
				   TCP_COOKIE_IN_ALWAYS : 0)
				| (tp->rx_opt.cookie_out_never ?
				   TCP_COOKIE_OUT_NEVER : 0);

		if (cvp != NULL) {
			ctd.tcpct_flags |= (cvp->s_data_in ?
					    TCP_S_DATA_IN : 0)
					 | (cvp->s_data_out ?
					    TCP_S_DATA_OUT : 0);

			ctd.tcpct_cookie_desired = cvp->cookie_desired;
			ctd.tcpct_s_data_desired = cvp->s_data_desired;

			memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
			       cvp->cookie_pair_size);
			ctd.tcpct_used = cvp->cookie_pair_size;
		}

		if (put_user(sizeof(ctd), optlen))
			return -EFAULT;
		if (copy_to_user(optval, &ctd, sizeof(ctd)))
			return -EFAULT;
		return 0;
	}
L
Linus Torvalds 已提交
2593 2594
	default:
		return -ENOPROTOOPT;
2595
	}
L
Linus Torvalds 已提交
2596 2597 2598 2599 2600 2601 2602 2603

	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, &val, len))
		return -EFAULT;
	return 0;
}

2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615
int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
		   int __user *optlen)
{
	struct inet_connection_sock *icsk = inet_csk(sk);

	if (level != SOL_TCP)
		return icsk->icsk_af_ops->getsockopt(sk, level, optname,
						     optval, optlen);
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
2616 2617
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2618
{
2619 2620 2621
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2622 2623
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2624 2625

EXPORT_SYMBOL(compat_tcp_getsockopt);
2626
#endif
L
Linus Torvalds 已提交
2627

2628
struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
H
Herbert Xu 已提交
2629 2630 2631 2632 2633
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	struct tcphdr *th;
	unsigned thlen;
	unsigned int seq;
2634
	__be32 delta;
H
Herbert Xu 已提交
2635
	unsigned int oldlen;
2636
	unsigned int mss;
H
Herbert Xu 已提交
2637 2638 2639 2640

	if (!pskb_may_pull(skb, sizeof(*th)))
		goto out;

2641
	th = tcp_hdr(skb);
H
Herbert Xu 已提交
2642 2643 2644 2645 2646 2647 2648
	thlen = th->doff * 4;
	if (thlen < sizeof(*th))
		goto out;

	if (!pskb_may_pull(skb, thlen))
		goto out;

2649
	oldlen = (u16)~skb->len;
H
Herbert Xu 已提交
2650 2651
	__skb_pull(skb, thlen);

2652 2653 2654 2655
	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

2656 2657
	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */
2658 2659 2660 2661 2662 2663 2664 2665 2666 2667
		int type = skb_shinfo(skb)->gso_type;

		if (unlikely(type &
			     ~(SKB_GSO_TCPV4 |
			       SKB_GSO_DODGY |
			       SKB_GSO_TCP_ECN |
			       SKB_GSO_TCPV6 |
			       0) ||
			     !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
			goto out;
2668

2669
		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2670 2671 2672 2673 2674

		segs = NULL;
		goto out;
	}

2675
	segs = skb_segment(skb, features);
H
Herbert Xu 已提交
2676 2677 2678
	if (IS_ERR(segs))
		goto out;

2679
	delta = htonl(oldlen + (thlen + mss));
H
Herbert Xu 已提交
2680 2681

	skb = segs;
2682
	th = tcp_hdr(skb);
H
Herbert Xu 已提交
2683 2684 2685 2686 2687
	seq = ntohl(th->seq);

	do {
		th->fin = th->psh = 0;

2688 2689
		th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
				       (__force u32)delta));
2690
		if (skb->ip_summed != CHECKSUM_PARTIAL)
2691 2692 2693
			th->check =
			     csum_fold(csum_partial(skb_transport_header(skb),
						    thlen, skb->csum));
H
Herbert Xu 已提交
2694

2695
		seq += mss;
H
Herbert Xu 已提交
2696
		skb = skb->next;
2697
		th = tcp_hdr(skb);
H
Herbert Xu 已提交
2698 2699 2700 2701 2702

		th->seq = htonl(seq);
		th->cwr = 0;
	} while (skb->next);

2703
	delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2704
		      skb->data_len);
2705 2706
	th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
				(__force u32)delta));
2707
	if (skb->ip_summed != CHECKSUM_PARTIAL)
2708 2709
		th->check = csum_fold(csum_partial(skb_transport_header(skb),
						   thlen, skb->csum));
H
Herbert Xu 已提交
2710 2711 2712 2713

out:
	return segs;
}
H
Herbert Xu 已提交
2714
EXPORT_SYMBOL(tcp_tso_segment);
H
Herbert Xu 已提交
2715

H
Herbert Xu 已提交
2716 2717 2718 2719 2720 2721
struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
{
	struct sk_buff **pp = NULL;
	struct sk_buff *p;
	struct tcphdr *th;
	struct tcphdr *th2;
2722
	unsigned int len;
H
Herbert Xu 已提交
2723
	unsigned int thlen;
2724
	__be32 flags;
H
Herbert Xu 已提交
2725
	unsigned int mss = 1;
2726 2727
	unsigned int hlen;
	unsigned int off;
H
Herbert Xu 已提交
2728
	int flush = 1;
H
Herbert Xu 已提交
2729
	int i;
H
Herbert Xu 已提交
2730

2731 2732 2733 2734 2735 2736 2737 2738
	off = skb_gro_offset(skb);
	hlen = off + sizeof(*th);
	th = skb_gro_header_fast(skb, off);
	if (skb_gro_header_hard(skb, hlen)) {
		th = skb_gro_header_slow(skb, hlen, off);
		if (unlikely(!th))
			goto out;
	}
H
Herbert Xu 已提交
2739 2740 2741 2742 2743

	thlen = th->doff * 4;
	if (thlen < sizeof(*th))
		goto out;

2744 2745 2746 2747 2748 2749
	hlen = off + thlen;
	if (skb_gro_header_hard(skb, hlen)) {
		th = skb_gro_header_slow(skb, hlen, off);
		if (unlikely(!th))
			goto out;
	}
H
Herbert Xu 已提交
2750

2751
	skb_gro_pull(skb, thlen);
H
Herbert Xu 已提交
2752

2753
	len = skb_gro_len(skb);
H
Herbert Xu 已提交
2754 2755 2756 2757 2758 2759 2760 2761
	flags = tcp_flag_word(th);

	for (; (p = *head); head = &p->next) {
		if (!NAPI_GRO_CB(p)->same_flow)
			continue;

		th2 = tcp_hdr(p);

H
Herbert Xu 已提交
2762
		if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
H
Herbert Xu 已提交
2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}

		goto found;
	}

	goto out_check_final;

found:
	flush = NAPI_GRO_CB(p)->flush;
2774 2775 2776 2777
	flush |= (__force int)(flags & TCP_FLAG_CWR);
	flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
		  ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
	flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
2778
	for (i = sizeof(*th); i < thlen; i += 4)
H
Herbert Xu 已提交
2779 2780
		flush |= *(u32 *)((u8 *)th + i) ^
			 *(u32 *)((u8 *)th2 + i);
H
Herbert Xu 已提交
2781

H
Herbert Xu 已提交
2782
	mss = skb_shinfo(p)->gso_size;
H
Herbert Xu 已提交
2783

H
Herbert Xu 已提交
2784
	flush |= (len - 1) >= mss;
H
Herbert Xu 已提交
2785
	flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
H
Herbert Xu 已提交
2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796

	if (flush || skb_gro_receive(head, skb)) {
		mss = 1;
		goto out_check_final;
	}

	p = *head;
	th2 = tcp_hdr(p);
	tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);

out_check_final:
2797
	flush = len < mss;
2798 2799 2800
	flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
					TCP_FLAG_RST | TCP_FLAG_SYN |
					TCP_FLAG_FIN));
H
Herbert Xu 已提交
2801 2802 2803 2804 2805 2806 2807 2808 2809

	if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
		pp = head;

out:
	NAPI_GRO_CB(skb)->flush |= flush;

	return pp;
}
H
Herbert Xu 已提交
2810
EXPORT_SYMBOL(tcp_gro_receive);
H
Herbert Xu 已提交
2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826

int tcp_gro_complete(struct sk_buff *skb)
{
	struct tcphdr *th = tcp_hdr(skb);

	skb->csum_start = skb_transport_header(skb) - skb->head;
	skb->csum_offset = offsetof(struct tcphdr, check);
	skb->ip_summed = CHECKSUM_PARTIAL;

	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;

	if (th->cwr)
		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;

	return 0;
}
H
Herbert Xu 已提交
2827
EXPORT_SYMBOL(tcp_gro_complete);
H
Herbert Xu 已提交
2828

2829 2830
#ifdef CONFIG_TCP_MD5SIG
static unsigned long tcp_md5sig_users;
2831
static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2832 2833
static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);

2834
static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849
{
	int cpu;
	for_each_possible_cpu(cpu) {
		struct tcp_md5sig_pool *p = *per_cpu_ptr(pool, cpu);
		if (p) {
			if (p->md5_desc.tfm)
				crypto_free_hash(p->md5_desc.tfm);
			kfree(p);
		}
	}
	free_percpu(pool);
}

void tcp_free_md5sig_pool(void)
{
2850
	struct tcp_md5sig_pool * __percpu *pool = NULL;
2851

2852
	spin_lock_bh(&tcp_md5sig_pool_lock);
2853 2854 2855 2856
	if (--tcp_md5sig_users == 0) {
		pool = tcp_md5sig_pool;
		tcp_md5sig_pool = NULL;
	}
2857
	spin_unlock_bh(&tcp_md5sig_pool_lock);
2858 2859 2860 2861 2862 2863
	if (pool)
		__tcp_free_md5sig_pool(pool);
}

EXPORT_SYMBOL(tcp_free_md5sig_pool);

2864 2865
static struct tcp_md5sig_pool * __percpu *
__tcp_alloc_md5sig_pool(struct sock *sk)
2866 2867
{
	int cpu;
2868
	struct tcp_md5sig_pool * __percpu *pool;
2869 2870 2871 2872 2873 2874 2875 2876 2877

	pool = alloc_percpu(struct tcp_md5sig_pool *);
	if (!pool)
		return NULL;

	for_each_possible_cpu(cpu) {
		struct tcp_md5sig_pool *p;
		struct crypto_hash *hash;

2878
		p = kzalloc(sizeof(*p), sk->sk_allocation);
2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894
		if (!p)
			goto out_free;
		*per_cpu_ptr(pool, cpu) = p;

		hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
		if (!hash || IS_ERR(hash))
			goto out_free;

		p->md5_desc.tfm = hash;
	}
	return pool;
out_free:
	__tcp_free_md5sig_pool(pool);
	return NULL;
}

2895
struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2896
{
2897
	struct tcp_md5sig_pool * __percpu *pool;
2898 2899 2900
	int alloc = 0;

retry:
2901
	spin_lock_bh(&tcp_md5sig_pool_lock);
2902 2903 2904
	pool = tcp_md5sig_pool;
	if (tcp_md5sig_users++ == 0) {
		alloc = 1;
2905
		spin_unlock_bh(&tcp_md5sig_pool_lock);
2906 2907
	} else if (!pool) {
		tcp_md5sig_users--;
2908
		spin_unlock_bh(&tcp_md5sig_pool_lock);
2909 2910 2911
		cpu_relax();
		goto retry;
	} else
2912
		spin_unlock_bh(&tcp_md5sig_pool_lock);
2913 2914 2915

	if (alloc) {
		/* we cannot hold spinlock here because this may sleep. */
2916 2917 2918
		struct tcp_md5sig_pool * __percpu *p;

		p = __tcp_alloc_md5sig_pool(sk);
2919
		spin_lock_bh(&tcp_md5sig_pool_lock);
2920 2921
		if (!p) {
			tcp_md5sig_users--;
2922
			spin_unlock_bh(&tcp_md5sig_pool_lock);
2923 2924 2925 2926 2927
			return NULL;
		}
		pool = tcp_md5sig_pool;
		if (pool) {
			/* oops, it has already been assigned. */
2928
			spin_unlock_bh(&tcp_md5sig_pool_lock);
2929 2930 2931
			__tcp_free_md5sig_pool(p);
		} else {
			tcp_md5sig_pool = pool = p;
2932
			spin_unlock_bh(&tcp_md5sig_pool_lock);
2933 2934 2935 2936 2937 2938 2939
		}
	}
	return pool;
}

EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
2940 2941 2942 2943 2944 2945 2946 2947 2948

/**
 *	tcp_get_md5sig_pool - get md5sig_pool for this user
 *
 *	We use percpu structure, so if we succeed, we exit with preemption
 *	and BH disabled, to make sure another thread or softirq handling
 *	wont try to get same context.
 */
struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
2949
{
2950
	struct tcp_md5sig_pool * __percpu *p;
E
Eric Dumazet 已提交
2951 2952 2953 2954

	local_bh_disable();

	spin_lock(&tcp_md5sig_pool_lock);
2955 2956 2957
	p = tcp_md5sig_pool;
	if (p)
		tcp_md5sig_users++;
E
Eric Dumazet 已提交
2958 2959 2960 2961
	spin_unlock(&tcp_md5sig_pool_lock);

	if (p)
		return *per_cpu_ptr(p, smp_processor_id());
2962

E
Eric Dumazet 已提交
2963 2964 2965 2966
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
2967

E
Eric Dumazet 已提交
2968
void tcp_put_md5sig_pool(void)
2969
{
E
Eric Dumazet 已提交
2970
	local_bh_enable();
2971
	tcp_free_md5sig_pool();
2972
}
E
Eric Dumazet 已提交
2973
EXPORT_SYMBOL(tcp_put_md5sig_pool);
2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030

int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
			struct tcphdr *th)
{
	struct scatterlist sg;
	int err;

	__sum16 old_checksum = th->check;
	th->check = 0;
	/* options aren't included in the hash */
	sg_init_one(&sg, th, sizeof(struct tcphdr));
	err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(struct tcphdr));
	th->check = old_checksum;
	return err;
}

EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
			  struct sk_buff *skb, unsigned header_len)
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
	struct hash_desc *desc = &hp->md5_desc;
	unsigned i;
	const unsigned head_data_len = skb_headlen(skb) > header_len ?
				       skb_headlen(skb) - header_len : 0;
	const struct skb_shared_info *shi = skb_shinfo(skb);

	sg_init_table(&sg, 1);

	sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
	if (crypto_hash_update(desc, &sg, head_data_len))
		return 1;

	for (i = 0; i < shi->nr_frags; ++i) {
		const struct skb_frag_struct *f = &shi->frags[i];
		sg_set_page(&sg, f->page, f->size, f->page_offset);
		if (crypto_hash_update(desc, &sg, f->size))
			return 1;
	}

	return 0;
}

EXPORT_SYMBOL(tcp_md5_hash_skb_data);

int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, struct tcp_md5sig_key *key)
{
	struct scatterlist sg;

	sg_init_one(&sg, key->key, key->keylen);
	return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
}

EXPORT_SYMBOL(tcp_md5_hash_key);

3031 3032
#endif

3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161
/**
 * Each Responder maintains up to two secret values concurrently for
 * efficient secret rollover.  Each secret value has 4 states:
 *
 * Generating.  (tcp_secret_generating != tcp_secret_primary)
 *    Generates new Responder-Cookies, but not yet used for primary
 *    verification.  This is a short-term state, typically lasting only
 *    one round trip time (RTT).
 *
 * Primary.  (tcp_secret_generating == tcp_secret_primary)
 *    Used both for generation and primary verification.
 *
 * Retiring.  (tcp_secret_retiring != tcp_secret_secondary)
 *    Used for verification, until the first failure that can be
 *    verified by the newer Generating secret.  At that time, this
 *    cookie's state is changed to Secondary, and the Generating
 *    cookie's state is changed to Primary.  This is a short-term state,
 *    typically lasting only one round trip time (RTT).
 *
 * Secondary.  (tcp_secret_retiring == tcp_secret_secondary)
 *    Used for secondary verification, after primary verification
 *    failures.  This state lasts no more than twice the Maximum Segment
 *    Lifetime (2MSL).  Then, the secret is discarded.
 */
struct tcp_cookie_secret {
	/* The secret is divided into two parts.  The digest part is the
	 * equivalent of previously hashing a secret and saving the state,
	 * and serves as an initialization vector (IV).  The message part
	 * serves as the trailing secret.
	 */
	u32				secrets[COOKIE_WORKSPACE_WORDS];
	unsigned long			expires;
};

#define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
#define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
#define TCP_SECRET_LIFE (HZ * 600)

static struct tcp_cookie_secret tcp_secret_one;
static struct tcp_cookie_secret tcp_secret_two;

/* Essentially a circular list, without dynamic allocation. */
static struct tcp_cookie_secret *tcp_secret_generating;
static struct tcp_cookie_secret *tcp_secret_primary;
static struct tcp_cookie_secret *tcp_secret_retiring;
static struct tcp_cookie_secret *tcp_secret_secondary;

static DEFINE_SPINLOCK(tcp_secret_locker);

/* Select a pseudo-random word in the cookie workspace.
 */
static inline u32 tcp_cookie_work(const u32 *ws, const int n)
{
	return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
}

/* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
 * Called in softirq context.
 * Returns: 0 for success.
 */
int tcp_cookie_generator(u32 *bakery)
{
	unsigned long jiffy = jiffies;

	if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
		spin_lock_bh(&tcp_secret_locker);
		if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
			/* refreshed by another */
			memcpy(bakery,
			       &tcp_secret_generating->secrets[0],
			       COOKIE_WORKSPACE_WORDS);
		} else {
			/* still needs refreshing */
			get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);

			/* The first time, paranoia assumes that the
			 * randomization function isn't as strong.  But,
			 * this secret initialization is delayed until
			 * the last possible moment (packet arrival).
			 * Although that time is observable, it is
			 * unpredictably variable.  Mash in the most
			 * volatile clock bits available, and expire the
			 * secret extra quickly.
			 */
			if (unlikely(tcp_secret_primary->expires ==
				     tcp_secret_secondary->expires)) {
				struct timespec tv;

				getnstimeofday(&tv);
				bakery[COOKIE_DIGEST_WORDS+0] ^=
					(u32)tv.tv_nsec;

				tcp_secret_secondary->expires = jiffy
					+ TCP_SECRET_1MSL
					+ (0x0f & tcp_cookie_work(bakery, 0));
			} else {
				tcp_secret_secondary->expires = jiffy
					+ TCP_SECRET_LIFE
					+ (0xff & tcp_cookie_work(bakery, 1));
				tcp_secret_primary->expires = jiffy
					+ TCP_SECRET_2MSL
					+ (0x1f & tcp_cookie_work(bakery, 2));
			}
			memcpy(&tcp_secret_secondary->secrets[0],
			       bakery, COOKIE_WORKSPACE_WORDS);

			rcu_assign_pointer(tcp_secret_generating,
					   tcp_secret_secondary);
			rcu_assign_pointer(tcp_secret_retiring,
					   tcp_secret_primary);
			/*
			 * Neither call_rcu() nor synchronize_rcu() needed.
			 * Retiring data is not freed.  It is replaced after
			 * further (locked) pointer updates, and a quiet time
			 * (minimum 1MSL, maximum LIFE - 2MSL).
			 */
		}
		spin_unlock_bh(&tcp_secret_locker);
	} else {
		rcu_read_lock_bh();
		memcpy(bakery,
		       &rcu_dereference(tcp_secret_generating)->secrets[0],
		       COOKIE_WORKSPACE_WORDS);
		rcu_read_unlock_bh();
	}
	return 0;
}
EXPORT_SYMBOL(tcp_cookie_generator);

A
Andi Kleen 已提交
3162 3163
void tcp_done(struct sock *sk)
{
3164
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3165
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);

	sk->sk_shutdown = SHUTDOWN_MASK;

	if (!sock_flag(sk, SOCK_DEAD))
		sk->sk_state_change(sk);
	else
		inet_csk_destroy_sock(sk);
}
EXPORT_SYMBOL_GPL(tcp_done);

3179
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
	if (!str)
		return 0;
	thash_entries = simple_strtoul(str, &str, 0);
	return 1;
}
__setup("thash_entries=", set_thash_entries);

void __init tcp_init(void)
{
	struct sk_buff *skb = NULL;
3194
	unsigned long nr_pages, limit;
3195
	int order, i, max_share;
3196
	unsigned long jiffy = jiffies;
L
Linus Torvalds 已提交
3197

3198
	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
L
Linus Torvalds 已提交
3199

3200
	percpu_counter_init(&tcp_sockets_allocated, 0);
3201
	percpu_counter_init(&tcp_orphan_count, 0);
3202 3203 3204
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3205
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3206 3207 3208 3209 3210 3211

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3212
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3213
		alloc_large_system_hash("TCP established",
3214
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3215
					thash_entries,
3216
					(totalram_pages >= 128 * 1024) ?
3217
					13 : 15,
3218
					0,
L
Linus Torvalds 已提交
3219
					NULL,
3220
					&tcp_hashinfo.ehash_mask,
3221
					thash_entries ? 0 : 512 * 1024);
3222
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3223 3224
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
L
Linus Torvalds 已提交
3225
	}
3226 3227
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3228
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3229
		alloc_large_system_hash("TCP bind",
3230
					sizeof(struct inet_bind_hashbucket),
3231
					tcp_hashinfo.ehash_mask + 1,
3232
					(totalram_pages >= 128 * 1024) ?
3233
					13 : 15,
3234
					0,
3235
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3236 3237
					NULL,
					64 * 1024);
3238 3239 3240 3241
	tcp_hashinfo.bhash_size = 1 << tcp_hashinfo.bhash_size;
	for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
		spin_lock_init(&tcp_hashinfo.bhash[i].lock);
		INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
L
Linus Torvalds 已提交
3242 3243 3244 3245 3246 3247
	}

	/* Try to be a bit smarter and adjust defaults depending
	 * on available memory.
	 */
	for (order = 0; ((1 << order) << PAGE_SHIFT) <
3248
			(tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
L
Linus Torvalds 已提交
3249 3250
			order++)
		;
3251
	if (order >= 4) {
3252
		tcp_death_row.sysctl_max_tw_buckets = 180000;
L
Linus Torvalds 已提交
3253 3254 3255
		sysctl_tcp_max_orphans = 4096 << (order - 4);
		sysctl_max_syn_backlog = 1024;
	} else if (order < 3) {
3256
		tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
L
Linus Torvalds 已提交
3257 3258 3259 3260
		sysctl_tcp_max_orphans >>= (3 - order);
		sysctl_max_syn_backlog = 128;
	}

3261 3262 3263 3264
	/* Set the pressure threshold to be a fraction of global memory that
	 * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
	 * memory, with a floor of 128 pages.
	 */
3265 3266 3267
	nr_pages = totalram_pages - totalhigh_pages;
	limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
	limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
3268 3269 3270
	limit = max(limit, 128UL);
	sysctl_tcp_mem[0] = limit / 4 * 3;
	sysctl_tcp_mem[1] = limit;
3271
	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
L
Linus Torvalds 已提交
3272

3273
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
3274 3275 3276
	limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
	max_share = min(4UL*1024*1024, limit);

3277
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3278 3279 3280
	sysctl_tcp_wmem[1] = 16*1024;
	sysctl_tcp_wmem[2] = max(64*1024, max_share);

3281
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3282 3283
	sysctl_tcp_rmem[1] = 87380;
	sysctl_tcp_rmem[2] = max(87380, max_share);
L
Linus Torvalds 已提交
3284 3285

	printk(KERN_INFO "TCP: Hash tables configured "
3286 3287
	       "(established %u bind %u)\n",
	       tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3288 3289

	tcp_register_congestion_control(&tcp_reno);
3290 3291 3292 3293 3294 3295 3296 3297 3298

	memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
	memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
	tcp_secret_one.expires = jiffy; /* past due */
	tcp_secret_two.expires = jiffy; /* past due */
	tcp_secret_generating = &tcp_secret_one;
	tcp_secret_primary = &tcp_secret_one;
	tcp_secret_retiring = &tcp_secret_two;
	tcp_secret_secondary = &tcp_secret_two;
L
Linus Torvalds 已提交
3299 3300 3301 3302 3303 3304 3305 3306 3307 3308
}

EXPORT_SYMBOL(tcp_close);
EXPORT_SYMBOL(tcp_disconnect);
EXPORT_SYMBOL(tcp_getsockopt);
EXPORT_SYMBOL(tcp_ioctl);
EXPORT_SYMBOL(tcp_poll);
EXPORT_SYMBOL(tcp_read_sock);
EXPORT_SYMBOL(tcp_recvmsg);
EXPORT_SYMBOL(tcp_sendmsg);
J
Jens Axboe 已提交
3309
EXPORT_SYMBOL(tcp_splice_read);
L
Linus Torvalds 已提交
3310 3311 3312
EXPORT_SYMBOL(tcp_sendpage);
EXPORT_SYMBOL(tcp_setsockopt);
EXPORT_SYMBOL(tcp_shutdown);