tcp.c 86.1 KB
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/*
 * 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
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 *		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
 */

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#include <linux/kernel.h>
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#include <linux/module.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
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#include <linux/skbuff.h>
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#include <linux/scatterlist.h>
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#include <linux/splice.h>
#include <linux/net.h>
#include <linux/socket.h>
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#include <linux/random.h>
#include <linux/bootmem.h>
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#include <linux/highmem.h>
#include <linux/swap.h>
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#include <linux/cache.h>
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#include <linux/err.h>
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#include <linux/crypto.h>
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#include <linux/time.h>
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#include <linux/slab.h>
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#include <net/icmp.h>
#include <net/tcp.h>
#include <net/xfrm.h>
#include <net/ip.h>
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#include <net/netdma.h>
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#include <net/sock.h>
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#include <asm/uaccess.h>
#include <asm/ioctls.h>

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int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
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struct percpu_counter tcp_orphan_count;
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EXPORT_SYMBOL_GPL(tcp_orphan_count);

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int sysctl_tcp_mem[3] __read_mostly;
int sysctl_tcp_wmem[3] __read_mostly;
int sysctl_tcp_rmem[3] __read_mostly;
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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);
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/*
 * Current number of TCP sockets.
 */
struct percpu_counter tcp_sockets_allocated;
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EXPORT_SYMBOL(tcp_sockets_allocated);

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/*
 * TCP splice context
 */
struct tcp_splice_state {
	struct pipe_inode_info *pipe;
	size_t len;
	unsigned int flags;
};

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/*
 * Pressure flag: try to collapse.
 * Technical note: it is used by multiple contexts non atomically.
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 * All the __sk_mem_schedule() is of this nature: accounting
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 * is strict, actions are advisory and have some latency.
 */
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int tcp_memory_pressure __read_mostly;
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EXPORT_SYMBOL(tcp_memory_pressure);

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void tcp_enter_memory_pressure(struct sock *sk)
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{
	if (!tcp_memory_pressure) {
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		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
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		tcp_memory_pressure = 1;
	}
}
EXPORT_SYMBOL(tcp_enter_memory_pressure);

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/* 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;
}

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/*
 *	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);

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	sock_poll_wait(file, sk_sleep(sk), wait);
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	if (sk->sk_state == TCP_LISTEN)
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		return inet_csk_listen_poll(sk);
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	/* Socket is not locked. We are protected from async events
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	 * by poll logic and correct handling of state changes
	 * made by other threads is impossible in any case.
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	 */

	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
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	 * solve this dilemma. I would prefer, if POLLHUP were maskable,
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	 * then we could set it on SND_SHUTDOWN. BTW examples given
	 * in Stevens' books assume exactly this behaviour, it explains
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	 * why POLLHUP is incompatible with POLLOUT.	--ANK
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	 *
	 * 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)
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		mask |= POLLIN | POLLRDNORM | POLLRDHUP;
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	/* Connected? */
	if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) {
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		int target = sock_rcvlowat(sk, 0, INT_MAX);

		if (tp->urg_seq == tp->copied_seq &&
		    !sock_flag(sk, SOCK_URGINLINE) &&
		    tp->urg_data)
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			target++;
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		/* Potential race condition. If read of tp below will
		 * escape above sk->sk_state, we can be illegally awaken
		 * in SYN_* states. */
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		if (tp->rcv_nxt - tp->copied_seq >= target)
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			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;
}
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EXPORT_SYMBOL(tcp_poll);
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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)) {
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			struct sk_buff *skb;

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			answ = tp->rcv_nxt - tp->copied_seq;

			/* Subtract 1, if FIN is in queue. */
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			skb = skb_peek_tail(&sk->sk_receive_queue);
			if (answ && skb)
				answ -= tcp_hdr(skb)->fin;
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		} 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;
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	}
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	return put_user(answ, (int __user *)arg);
}
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EXPORT_SYMBOL(tcp_ioctl);
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static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
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	TCP_SKB_CB(skb)->flags |= TCPHDR_PSH;
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	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));
}

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static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
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{
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	struct tcp_sock *tp = tcp_sk(sk);
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	struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);

	skb->csum    = 0;
	tcb->seq     = tcb->end_seq = tp->write_seq;
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	tcb->flags   = TCPHDR_ACK;
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	tcb->sacked  = 0;
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	skb_header_release(skb);
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	tcp_add_write_queue_tail(sk, skb);
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	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
	};

	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;

611
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
612 613 614 615 616 617 618 619 620 621
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

622
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660
	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;

661 662
		if (!timeo)
			break;
J
Jens Axboe 已提交
663 664 665 666
		release_sock(sk);
		lock_sock(sk);

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

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
679
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
680

681
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
682 683 684 685 686 687 688 689
{
	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) {
690
		if (sk_wmem_schedule(sk, skb->truesize)) {
691 692 693 694 695 696 697 698 699
			/*
			 * 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 {
700
		sk->sk_prot->enter_memory_pressure(sk);
701 702 703 704 705
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
706 707 708 709
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
710
	u32 xmit_size_goal, old_size_goal;
I
Ilpo Järvinen 已提交
711 712 713 714 715 716 717 718 719 720

	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);
721 722 723 724 725 726 727 728 729 730 731

		/* 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
732 733
	}

734
	return max(xmit_size_goal, mss_now);
I
Ilpo Järvinen 已提交
735 736 737 738 739 740 741 742 743 744 745 746
}

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
747 748 749 750
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);
751
	int mss_now, size_goal;
L
Linus Torvalds 已提交
752 753 754 755 756 757 758 759 760 761 762
	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
763
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
764 765 766 767
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
768
		goto out_err;
L
Linus Torvalds 已提交
769 770

	while (psize > 0) {
771
		struct sk_buff *skb = tcp_write_queue_tail(sk);
L
Linus Torvalds 已提交
772 773 774 775 776
		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);

777
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
778 779 780 781
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

782
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
L
Linus Torvalds 已提交
783 784 785
			if (!skb)
				goto wait_for_memory;

786
			skb_entail(sk, skb);
787
			copy = size_goal;
L
Linus Torvalds 已提交
788 789 790 791 792 793 794 795 796 797 798
		}

		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;
		}
799
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
800
			goto wait_for_memory;
801

L
Linus Torvalds 已提交
802 803 804 805 806 807 808 809 810 811 812
		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;
813
		sk_mem_charge(sk, copy);
814
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
815 816
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
817
		skb_shinfo(skb)->gso_segs = 0;
L
Linus Torvalds 已提交
818 819

		if (!copied)
C
Changli Gao 已提交
820
			TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
821 822 823 824 825 826

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

827
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
828 829 830 831
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
832
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
833
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
834 835 836 837 838 839 840
			tcp_push_one(sk, mss_now);
		continue;

wait_for_sndbuf:
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
		if (copied)
841
			tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
L
Linus Torvalds 已提交
842 843 844 845

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

I
Ilpo Järvinen 已提交
846
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
847 848 849 850
	}

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

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

861 862
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
863 864 865 866
{
	ssize_t res;

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

	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;
}
E
Eric Dumazet 已提交
878
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
879 880 881 882

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

K
Krishna Kumar 已提交
883
static inline int select_size(struct sock *sk, int sg)
L
Linus Torvalds 已提交
884
{
885
	struct tcp_sock *tp = tcp_sk(sk);
886
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
887

K
Krishna Kumar 已提交
888
	if (sg) {
889
		if (sk_can_gso(sk))
890 891 892 893 894 895 896 897 898
			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
899 900 901 902

	return tmp;
}

903
int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
L
Linus Torvalds 已提交
904 905 906 907 908 909
		size_t size)
{
	struct iovec *iov;
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
	int iovlen, flags;
910
	int mss_now, size_goal;
K
Krishna Kumar 已提交
911
	int sg, err, copied;
L
Linus Torvalds 已提交
912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927
	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
928
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
929 930 931 932 933 934 935 936

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

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
937
		goto out_err;
L
Linus Torvalds 已提交
938

K
Krishna Kumar 已提交
939 940
	sg = sk->sk_route_caps & NETIF_F_SG;

L
Linus Torvalds 已提交
941 942 943 944 945 946 947
	while (--iovlen >= 0) {
		int seglen = iov->iov_len;
		unsigned char __user *from = iov->iov_base;

		iov++;

		while (seglen > 0) {
948 949
			int copy = 0;
			int max = size_goal;
L
Linus Torvalds 已提交
950

951
			skb = tcp_write_queue_tail(sk);
952 953 954 955 956
			if (tcp_send_head(sk)) {
				if (skb->ip_summed == CHECKSUM_NONE)
					max = mss_now;
				copy = max - skb->len;
			}
L
Linus Torvalds 已提交
957

958
			if (copy <= 0) {
L
Linus Torvalds 已提交
959 960 961 962 963 964 965
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
966 967 968
				skb = sk_stream_alloc_skb(sk,
							  select_size(sk, sg),
							  sk->sk_allocation);
L
Linus Torvalds 已提交
969 970 971 972 973 974
				if (!skb)
					goto wait_for_memory;

				/*
				 * Check whether we can use HW checksum.
				 */
975
				if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
976
					skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
977

978
				skb_entail(sk, skb);
979
				copy = size_goal;
980
				max = size_goal;
L
Linus Torvalds 已提交
981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004
			}

			/* 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
1005
				} else if (i == MAX_SKB_FRAGS || !sg) {
L
Linus Torvalds 已提交
1006 1007 1008 1009 1010 1011 1012 1013 1014 1015
					/* 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;
1016
						off = 0;
L
Linus Torvalds 已提交
1017
					}
1018
				} else
1019
					off = 0;
1020 1021 1022 1023

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

1024
				if (!sk_wmem_schedule(sk, copy))
1025
					goto wait_for_memory;
L
Linus Torvalds 已提交
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

				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)
C
Changli Gao 已提交
1066
				TCP_SKB_CB(skb)->flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
1067 1068 1069

			tp->write_seq += copy;
			TCP_SKB_CB(skb)->end_seq += copy;
1070
			skb_shinfo(skb)->gso_segs = 0;
L
Linus Torvalds 已提交
1071 1072 1073 1074 1075 1076

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

1077
			if (skb->len < max || (flags & MSG_OOB))
L
Linus Torvalds 已提交
1078 1079 1080 1081
				continue;

			if (forced_push(tp)) {
				tcp_mark_push(tp, skb);
1082
				__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1083
			} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
1084 1085 1086 1087 1088 1089 1090
				tcp_push_one(sk, mss_now);
			continue;

wait_for_sndbuf:
			set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
			if (copied)
1091
				tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
L
Linus Torvalds 已提交
1092 1093 1094 1095

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

I
Ilpo Järvinen 已提交
1096
			mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1097 1098 1099 1100 1101
		}
	}

out:
	if (copied)
1102
		tcp_push(sk, flags, mss_now, tp->nonagle);
L
Linus Torvalds 已提交
1103 1104 1105 1106 1107 1108
	TCP_CHECK_TIMER(sk);
	release_sock(sk);
	return copied;

do_fault:
	if (!skb->len) {
1109 1110 1111 1112 1113
		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);
1114
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125
	}

do_error:
	if (copied)
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
	TCP_CHECK_TIMER(sk);
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1126
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1127 1128 1129 1130 1131 1132

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

1133
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182
{
	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.
 */
1183
void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1184 1185 1186 1187 1188 1189 1190
{
	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);

1191 1192 1193
	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
1194 1195
#endif

1196 1197
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1198 1199
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1200
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1201
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1202
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1203 1204 1205 1206 1207 1208
		    /*
		     * 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.
		     */
1209 1210 1211 1212 1213
		    (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
1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247
			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);

1248
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1249 1250 1251 1252 1253

	/* 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
1254
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1255 1256 1257 1258 1259 1260
	local_bh_enable();

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

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 1291 1292 1293
#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
1294 1295 1296 1297 1298 1299 1300
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;
1301
		if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1302
			offset--;
1303
		if (offset < skb->len || tcp_hdr(skb)->fin) {
L
Linus Torvalds 已提交
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 1332 1333 1334
			*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) {
1335 1336
			int used;
			size_t len;
L
Linus Torvalds 已提交
1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347

			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);
1348 1349 1350 1351 1352
			if (used < 0) {
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1353 1354 1355 1356
				seq += used;
				copied += used;
				offset += used;
			}
1357 1358 1359 1360 1361 1362 1363 1364
			/*
			 * 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
1365 1366
				break;
		}
1367
		if (tcp_hdr(skb)->fin) {
1368
			sk_eat_skb(sk, skb, 0);
L
Linus Torvalds 已提交
1369 1370 1371
			++seq;
			break;
		}
1372
		sk_eat_skb(sk, skb, 0);
L
Linus Torvalds 已提交
1373 1374
		if (!desc->count)
			break;
1375
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1376 1377 1378 1379 1380 1381
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1382
	if (copied > 0)
1383
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1384 1385
	return copied;
}
E
Eric Dumazet 已提交
1386
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407

/*
 *	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
1408
	int copied_early = 0;
1409
	struct sk_buff *skb;
I
Ilpo Järvinen 已提交
1410
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433

	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
1434 1435 1436
#ifdef CONFIG_NET_DMA
	tp->ucopy.dma_chan = NULL;
	preempt_disable();
1437
	skb = skb_peek_tail(&sk->sk_receive_queue);
A
Andrew Morton 已提交
1438 1439 1440 1441 1442 1443 1444 1445
	{
		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 &&
1446
		    dma_find_channel(DMA_MEMCPY)) {
A
Andrew Morton 已提交
1447 1448 1449 1450 1451 1452 1453
			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
1454 1455
#endif

L
Linus Torvalds 已提交
1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470
	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. */

1471
		skb_queue_walk(&sk->sk_receive_queue, skb) {
L
Linus Torvalds 已提交
1472 1473 1474
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1475 1476 1477 1478 1479
			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
1480
				break;
1481

L
Linus Torvalds 已提交
1482
			offset = *seq - TCP_SKB_CB(skb)->seq;
1483
			if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1484 1485 1486
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1487
			if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1488
				goto found_fin_ok;
1489
			WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "
1490 1491 1492
					"copied %X seq %X rcvnxt %X fl %X\n",
					*seq, TCP_SKB_CB(skb)->seq,
					tp->rcv_nxt, flags);
1493
		}
L
Linus Torvalds 已提交
1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504

		/* 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 ||
1505
			    signal_pending(current))
L
Linus Torvalds 已提交
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 1537 1538 1539 1540
				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;
			}
		}

1541
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1542

1543
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1544 1545 1546 1547 1548 1549 1550 1551 1552
			/* 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;

1553 1554
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581

			/* 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.
			 */
1582
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1583 1584 1585 1586 1587
				goto do_prequeue;

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

1588 1589 1590 1591
#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
1592 1593 1594 1595 1596 1597 1598
		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
1599
#ifdef CONFIG_NET_DMA
1600
		tcp_service_net_dma(sk, false);  /* Don't block */
C
Chris Leech 已提交
1601 1602 1603
		tp->ucopy.wakeup = 0;
#endif

L
Linus Torvalds 已提交
1604 1605 1606 1607 1608 1609
		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

			if ((chunk = len - tp->ucopy.len) != 0) {
1610
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1611 1612 1613 1614 1615
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1616
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1617 1618 1619 1620
do_prequeue:
				tcp_prequeue_process(sk);

				if ((chunk = len - tp->ucopy.len) != 0) {
1621
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1622 1623 1624 1625 1626
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1627 1628
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
L
Linus Torvalds 已提交
1629 1630
			if (net_ratelimit())
				printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
1631
				       current->comm, task_pid_nr(current));
L
Linus Torvalds 已提交
1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648
			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
1649
						urg_hole++;
L
Linus Torvalds 已提交
1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
C
Chris Leech 已提交
1661 1662
#ifdef CONFIG_NET_DMA
			if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1663
				tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
C
Chris Leech 已提交
1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679

			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;
				}
1680 1681 1682

				dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);

C
Chris Leech 已提交
1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696
				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
1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708
			}
		}

		*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;
1709
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1710 1711 1712 1713
		}
		if (used + offset < skb->len)
			continue;

1714
		if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1715
			goto found_fin_ok;
C
Chris Leech 已提交
1716 1717 1718 1719
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
			copied_early = 0;
		}
L
Linus Torvalds 已提交
1720 1721 1722 1723 1724
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
C
Chris Leech 已提交
1725 1726 1727 1728
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
			copied_early = 0;
		}
L
Linus Torvalds 已提交
1729 1730 1731 1732
		break;
	} while (len > 0);

	if (user_recv) {
1733
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1734 1735 1736 1737 1738 1739 1740
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1741
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1742 1743 1744 1745 1746 1747 1748 1749 1750
				len -= chunk;
				copied += chunk;
			}
		}

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

C
Chris Leech 已提交
1751
#ifdef CONFIG_NET_DMA
1752 1753
	tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
	tp->ucopy.dma_chan = NULL;
C
Chris Leech 已提交
1754 1755 1756 1757 1758 1759 1760

	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
1761 1762 1763 1764 1765
	/* 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. */
1766
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777

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

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

recv_urg:
1778
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1779 1780
	goto out;
}
E
Eric Dumazet 已提交
1781
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
1782

I
Ilpo Järvinen 已提交
1783 1784 1785 1786 1787 1788 1789
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
1790
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1791 1792 1793 1794
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1795
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1796 1797 1798 1799

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1800
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1801 1802
		/* fall through */
	default:
1803
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1804
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1805 1806 1807 1808 1809 1810 1811 1812
	}

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

#ifdef STATE_TRACE
1813
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1814 1815 1816 1817
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1818 1819 1820 1821 1822 1823 1824
/*
 *	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.
 */

1825
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852
  /* 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
1853
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
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);
	}
}
E
Eric Dumazet 已提交
1874
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
1875 1876 1877 1878 1879

void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
1880
	int state;
L
Linus Torvalds 已提交
1881 1882 1883 1884 1885 1886 1887 1888

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

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

		/* Special case. */
1889
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
1890 1891 1892 1893 1894 1895 1896 1897 1898 1899

		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 -
1900
			  tcp_hdr(skb)->fin;
L
Linus Torvalds 已提交
1901 1902 1903 1904
		data_was_unread += len;
		__kfree_skb(skb);
	}

1905
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
1906

1907 1908 1909 1910
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

1911 1912 1913 1914 1915 1916
	/* 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
1917 1918 1919
	 */
	if (data_was_unread) {
		/* Unread data was tossed, zap the connection. */
1920
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
1921
		tcp_set_state(sk, TCP_CLOSE);
1922
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
1923 1924 1925
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
1926
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958
	} 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
1959 1960 1961 1962
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
1963 1964 1965 1966 1967 1968 1969 1970 1971
	/* 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);
1972
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
1973

H
Herbert Xu 已提交
1974 1975
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
1976 1977 1978
	/* 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
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

	/*	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);
1999 2000
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2001
		} else {
2002
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2003 2004

			if (tmo > TCP_TIMEWAIT_LEN) {
2005 2006
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2007 2008 2009 2010 2011 2012 2013
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2014 2015 2016
		int orphan_count = percpu_counter_read_positive(
						sk->sk_prot->orphan_count);

2017
		sk_mem_reclaim(sk);
2018
		if (tcp_too_many_orphans(sk, orphan_count)) {
L
Linus Torvalds 已提交
2019 2020 2021 2022 2023
			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);
2024 2025
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2026 2027 2028 2029
		}
	}

	if (sk->sk_state == TCP_CLOSE)
2030
		inet_csk_destroy_sock(sk);
L
Linus Torvalds 已提交
2031 2032 2033 2034 2035 2036 2037
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2038
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051

/* 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);
2052
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2053 2054 2055 2056 2057 2058 2059 2060 2061
	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) {
2062
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2063 2064 2065
	} 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
2066
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2067 2068 2069 2070 2071 2072 2073 2074 2075
		 * 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);
2076
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2077
	__skb_queue_purge(&tp->out_of_order_queue);
C
Chris Leech 已提交
2078 2079 2080
#ifdef CONFIG_NET_DMA
	__skb_queue_purge(&sk->sk_async_wait_queue);
#endif
L
Linus Torvalds 已提交
2081

E
Eric Dumazet 已提交
2082
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2083 2084 2085 2086 2087 2088 2089 2090 2091

	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;
2092
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2093
	tp->snd_cwnd = 2;
2094
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2095
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2096
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2097
	tp->snd_cwnd_cnt = 0;
2098
	tp->bytes_acked = 0;
2099
	tp->window_clamp = 0;
2100
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2101
	tcp_clear_retrans(tp);
2102
	inet_csk_delack_init(sk);
2103
	tcp_init_send_head(sk);
2104
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2105 2106
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2107
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2108 2109 2110 2111

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2112
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2113 2114 2115 2116

/*
 *	Socket option code for TCP.
 */
2117
static int do_tcp_setsockopt(struct sock *sk, int level,
2118
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2119 2120
{
	struct tcp_sock *tp = tcp_sk(sk);
2121
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2122 2123 2124
	int val;
	int err = 0;

2125 2126 2127
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2128 2129 2130 2131 2132 2133
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2134
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2135 2136 2137 2138 2139
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2140
		err = tcp_set_congestion_control(sk, name);
2141 2142 2143
		release_sock(sk);
		return err;
	}
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
	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;
2190 2191

			kref_init(&cvp->kref);
2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209
		}
		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);
			} else {
				cvp = tp->cookie_values;
			}
		}
2210

2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223
		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 */
			}
2224 2225

			tp->cookie_values = cvp;
2226 2227 2228 2229 2230 2231 2232
		}
		release_sock(sk);
		return err;
	}
	default:
		/* fallthru */
		break;
2233
	}
2234

L
Linus Torvalds 已提交
2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265
	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;
2266
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2267 2268 2269 2270 2271
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2272 2273 2274 2275 2276 2277 2278
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2279 2280 2281 2282 2283 2284 2285
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_dupack = val;
		break;

L
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2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303
	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;
2304
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315
		}
		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))) {
2316
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2317 2318 2319 2320
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2321
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340
			}
		}
		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
2341
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353
		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:
2354 2355 2356 2357
		/* 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
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2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373
		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) {
2374
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2375
		} else {
2376
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2377 2378
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2379 2380
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2381
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2382
				if (!(val & 1))
2383
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2384 2385 2386 2387
			}
		}
		break;

2388 2389 2390 2391 2392 2393 2394
#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
2395 2396 2397
	default:
		err = -ENOPROTOOPT;
		break;
2398 2399
	}

L
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2400 2401 2402 2403
	release_sock(sk);
	return err;
}

2404
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2405
		   unsigned int optlen)
2406 2407 2408 2409 2410 2411 2412 2413
{
	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);
}
E
Eric Dumazet 已提交
2414
EXPORT_SYMBOL(tcp_setsockopt);
2415 2416

#ifdef CONFIG_COMPAT
2417
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2418
			  char __user *optval, unsigned int optlen)
2419
{
2420 2421 2422
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2423 2424
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2425
EXPORT_SYMBOL(compat_tcp_setsockopt);
2426 2427
#endif

L
Linus Torvalds 已提交
2428 2429 2430 2431
/* 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);
2432
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2433 2434 2435 2436 2437
	u32 now = tcp_time_stamp;

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

	info->tcpi_state = sk->sk_state;
2438
	info->tcpi_ca_state = icsk->icsk_ca_state;
2439
	info->tcpi_retransmits = icsk->icsk_retransmits;
2440
	info->tcpi_probes = icsk->icsk_probes_out;
2441
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2442 2443 2444

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2445
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2446 2447 2448 2449 2450
		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;
2451
	}
L
Linus Torvalds 已提交
2452 2453 2454 2455

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

2456 2457
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2458
	info->tcpi_snd_mss = tp->mss_cache;
2459
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2460

2461 2462 2463 2464 2465 2466 2467
	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
2468 2469 2470 2471 2472
	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);
2473
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2474 2475
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2476
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491
	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);

2492 2493
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2494
{
2495
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508
	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:
2509
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2510 2511 2512 2513 2514 2515 2516 2517 2518 2519
		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
2520
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2521 2522
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2523
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2524 2525
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2526
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2527 2528
		break;
	case TCP_SYNCNT:
2529
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2530 2531 2532 2533 2534 2535 2536
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2537 2538
		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
2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558
		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:
2559
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2560
		break;
2561 2562 2563 2564 2565 2566 2567

	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;
2568
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2569 2570
			return -EFAULT;
		return 0;
2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606

	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;
	}
2607 2608 2609 2610 2611 2612
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
L
Linus Torvalds 已提交
2613 2614
	default:
		return -ENOPROTOOPT;
2615
	}
L
Linus Torvalds 已提交
2616 2617 2618 2619 2620 2621 2622 2623

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

2624 2625 2626 2627 2628 2629 2630 2631 2632 2633
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);
}
E
Eric Dumazet 已提交
2634
EXPORT_SYMBOL(tcp_getsockopt);
2635 2636

#ifdef CONFIG_COMPAT
2637 2638
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2639
{
2640 2641 2642
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2643 2644
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2645
EXPORT_SYMBOL(compat_tcp_getsockopt);
2646
#endif
L
Linus Torvalds 已提交
2647

2648
struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
H
Herbert Xu 已提交
2649 2650 2651 2652 2653
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	struct tcphdr *th;
	unsigned thlen;
	unsigned int seq;
2654
	__be32 delta;
H
Herbert Xu 已提交
2655
	unsigned int oldlen;
2656
	unsigned int mss;
H
Herbert Xu 已提交
2657 2658 2659 2660

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

2661
	th = tcp_hdr(skb);
H
Herbert Xu 已提交
2662 2663 2664 2665 2666 2667 2668
	thlen = th->doff * 4;
	if (thlen < sizeof(*th))
		goto out;

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

2669
	oldlen = (u16)~skb->len;
H
Herbert Xu 已提交
2670 2671
	__skb_pull(skb, thlen);

2672 2673 2674 2675
	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

2676 2677
	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */
2678 2679 2680 2681 2682 2683 2684 2685 2686 2687
		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;
2688

2689
		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
2690 2691 2692 2693 2694

		segs = NULL;
		goto out;
	}

2695
	segs = skb_segment(skb, features);
H
Herbert Xu 已提交
2696 2697 2698
	if (IS_ERR(segs))
		goto out;

2699
	delta = htonl(oldlen + (thlen + mss));
H
Herbert Xu 已提交
2700 2701

	skb = segs;
2702
	th = tcp_hdr(skb);
H
Herbert Xu 已提交
2703 2704 2705 2706 2707
	seq = ntohl(th->seq);

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

2708 2709
		th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
				       (__force u32)delta));
2710
		if (skb->ip_summed != CHECKSUM_PARTIAL)
2711 2712 2713
			th->check =
			     csum_fold(csum_partial(skb_transport_header(skb),
						    thlen, skb->csum));
H
Herbert Xu 已提交
2714

2715
		seq += mss;
H
Herbert Xu 已提交
2716
		skb = skb->next;
2717
		th = tcp_hdr(skb);
H
Herbert Xu 已提交
2718 2719 2720 2721 2722

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

2723
	delta = htonl(oldlen + (skb->tail - skb->transport_header) +
2724
		      skb->data_len);
2725 2726
	th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
				(__force u32)delta));
2727
	if (skb->ip_summed != CHECKSUM_PARTIAL)
2728 2729
		th->check = csum_fold(csum_partial(skb_transport_header(skb),
						   thlen, skb->csum));
H
Herbert Xu 已提交
2730 2731 2732 2733

out:
	return segs;
}
H
Herbert Xu 已提交
2734
EXPORT_SYMBOL(tcp_tso_segment);
H
Herbert Xu 已提交
2735

H
Herbert Xu 已提交
2736 2737 2738 2739 2740 2741
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;
2742
	unsigned int len;
H
Herbert Xu 已提交
2743
	unsigned int thlen;
2744
	__be32 flags;
H
Herbert Xu 已提交
2745
	unsigned int mss = 1;
2746 2747
	unsigned int hlen;
	unsigned int off;
H
Herbert Xu 已提交
2748
	int flush = 1;
H
Herbert Xu 已提交
2749
	int i;
H
Herbert Xu 已提交
2750

2751 2752 2753 2754 2755 2756 2757 2758
	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
2759 2760 2761 2762 2763

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

2764 2765 2766 2767 2768 2769
	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
2770

2771
	skb_gro_pull(skb, thlen);
H
Herbert Xu 已提交
2772

2773
	len = skb_gro_len(skb);
H
Herbert Xu 已提交
2774 2775 2776 2777 2778 2779 2780 2781
	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
2782
		if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
H
Herbert Xu 已提交
2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}

		goto found;
	}

	goto out_check_final;

found:
	flush = NAPI_GRO_CB(p)->flush;
2794 2795 2796 2797
	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);
2798
	for (i = sizeof(*th); i < thlen; i += 4)
H
Herbert Xu 已提交
2799 2800
		flush |= *(u32 *)((u8 *)th + i) ^
			 *(u32 *)((u8 *)th2 + i);
H
Herbert Xu 已提交
2801

H
Herbert Xu 已提交
2802
	mss = skb_shinfo(p)->gso_size;
H
Herbert Xu 已提交
2803

H
Herbert Xu 已提交
2804
	flush |= (len - 1) >= mss;
H
Herbert Xu 已提交
2805
	flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
H
Herbert Xu 已提交
2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816

	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:
2817
	flush = len < mss;
2818 2819 2820
	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
2821 2822 2823 2824 2825 2826 2827 2828 2829

	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
2830
EXPORT_SYMBOL(tcp_gro_receive);
H
Herbert Xu 已提交
2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846

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
2847
EXPORT_SYMBOL(tcp_gro_complete);
H
Herbert Xu 已提交
2848

2849 2850
#ifdef CONFIG_TCP_MD5SIG
static unsigned long tcp_md5sig_users;
2851
static struct tcp_md5sig_pool * __percpu *tcp_md5sig_pool;
2852 2853
static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);

2854
static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869
{
	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)
{
2870
	struct tcp_md5sig_pool * __percpu *pool = NULL;
2871

2872
	spin_lock_bh(&tcp_md5sig_pool_lock);
2873 2874 2875 2876
	if (--tcp_md5sig_users == 0) {
		pool = tcp_md5sig_pool;
		tcp_md5sig_pool = NULL;
	}
2877
	spin_unlock_bh(&tcp_md5sig_pool_lock);
2878 2879 2880 2881 2882
	if (pool)
		__tcp_free_md5sig_pool(pool);
}
EXPORT_SYMBOL(tcp_free_md5sig_pool);

2883 2884
static struct tcp_md5sig_pool * __percpu *
__tcp_alloc_md5sig_pool(struct sock *sk)
2885 2886
{
	int cpu;
2887
	struct tcp_md5sig_pool * __percpu *pool;
2888 2889 2890 2891 2892 2893 2894 2895 2896

	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;

2897
		p = kzalloc(sizeof(*p), sk->sk_allocation);
2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913
		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;
}

2914
struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
2915
{
2916
	struct tcp_md5sig_pool * __percpu *pool;
2917 2918 2919
	int alloc = 0;

retry:
2920
	spin_lock_bh(&tcp_md5sig_pool_lock);
2921 2922 2923
	pool = tcp_md5sig_pool;
	if (tcp_md5sig_users++ == 0) {
		alloc = 1;
2924
		spin_unlock_bh(&tcp_md5sig_pool_lock);
2925 2926
	} else if (!pool) {
		tcp_md5sig_users--;
2927
		spin_unlock_bh(&tcp_md5sig_pool_lock);
2928 2929 2930
		cpu_relax();
		goto retry;
	} else
2931
		spin_unlock_bh(&tcp_md5sig_pool_lock);
2932 2933 2934

	if (alloc) {
		/* we cannot hold spinlock here because this may sleep. */
2935 2936 2937
		struct tcp_md5sig_pool * __percpu *p;

		p = __tcp_alloc_md5sig_pool(sk);
2938
		spin_lock_bh(&tcp_md5sig_pool_lock);
2939 2940
		if (!p) {
			tcp_md5sig_users--;
2941
			spin_unlock_bh(&tcp_md5sig_pool_lock);
2942 2943 2944 2945 2946
			return NULL;
		}
		pool = tcp_md5sig_pool;
		if (pool) {
			/* oops, it has already been assigned. */
2947
			spin_unlock_bh(&tcp_md5sig_pool_lock);
2948 2949 2950
			__tcp_free_md5sig_pool(p);
		} else {
			tcp_md5sig_pool = pool = p;
2951
			spin_unlock_bh(&tcp_md5sig_pool_lock);
2952 2953 2954 2955 2956 2957
		}
	}
	return pool;
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
2958 2959 2960 2961 2962 2963 2964 2965 2966

/**
 *	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)
2967
{
2968
	struct tcp_md5sig_pool * __percpu *p;
E
Eric Dumazet 已提交
2969 2970 2971 2972

	local_bh_disable();

	spin_lock(&tcp_md5sig_pool_lock);
2973 2974 2975
	p = tcp_md5sig_pool;
	if (p)
		tcp_md5sig_users++;
E
Eric Dumazet 已提交
2976 2977 2978
	spin_unlock(&tcp_md5sig_pool_lock);

	if (p)
E
Eric Dumazet 已提交
2979
		return *this_cpu_ptr(p);
2980

E
Eric Dumazet 已提交
2981 2982 2983 2984
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
2985

E
Eric Dumazet 已提交
2986
void tcp_put_md5sig_pool(void)
2987
{
E
Eric Dumazet 已提交
2988
	local_bh_enable();
2989
	tcp_free_md5sig_pool();
2990
}
E
Eric Dumazet 已提交
2991
EXPORT_SYMBOL(tcp_put_md5sig_pool);
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

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);
3019
	struct sk_buff *frag_iter;
3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033

	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;
	}

3034 3035 3036 3037
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050
	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);

3051 3052
#endif

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 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181
/**
 * 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
3182 3183
void tcp_done(struct sock *sk)
{
3184
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3185
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198

	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);

3199
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213

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;
3214
	unsigned long nr_pages, limit;
3215
	int order, i, max_share;
3216
	unsigned long jiffy = jiffies;
L
Linus Torvalds 已提交
3217

3218
	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
L
Linus Torvalds 已提交
3219

3220
	percpu_counter_init(&tcp_sockets_allocated, 0);
3221
	percpu_counter_init(&tcp_orphan_count, 0);
3222 3223 3224
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3225
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3226 3227 3228 3229 3230 3231

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3232
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3233
		alloc_large_system_hash("TCP established",
3234
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
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					thash_entries,
3236
					(totalram_pages >= 128 * 1024) ?
3237
					13 : 15,
3238
					0,
L
Linus Torvalds 已提交
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					NULL,
3240
					&tcp_hashinfo.ehash_mask,
3241
					thash_entries ? 0 : 512 * 1024);
3242
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3243 3244
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
L
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	}
3246 3247
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3248
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3249
		alloc_large_system_hash("TCP bind",
3250
					sizeof(struct inet_bind_hashbucket),
3251
					tcp_hashinfo.ehash_mask + 1,
3252
					(totalram_pages >= 128 * 1024) ?
3253
					13 : 15,
3254
					0,
3255
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3256 3257
					NULL,
					64 * 1024);
3258 3259 3260 3261
	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);
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	}

	/* Try to be a bit smarter and adjust defaults depending
	 * on available memory.
	 */
	for (order = 0; ((1 << order) << PAGE_SHIFT) <
3268
			(tcp_hashinfo.bhash_size * sizeof(struct inet_bind_hashbucket));
L
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			order++)
		;
3271
	if (order >= 4) {
3272
		tcp_death_row.sysctl_max_tw_buckets = 180000;
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		sysctl_tcp_max_orphans = 4096 << (order - 4);
		sysctl_max_syn_backlog = 1024;
	} else if (order < 3) {
3276
		tcp_death_row.sysctl_max_tw_buckets >>= (3 - order);
L
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		sysctl_tcp_max_orphans >>= (3 - order);
		sysctl_max_syn_backlog = 128;
	}

3281 3282 3283 3284
	/* 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.
	 */
3285 3286 3287
	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);
3288 3289 3290
	limit = max(limit, 128UL);
	sysctl_tcp_mem[0] = limit / 4 * 3;
	sysctl_tcp_mem[1] = limit;
3291
	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
L
Linus Torvalds 已提交
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3293
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
3294 3295 3296
	limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
	max_share = min(4UL*1024*1024, limit);

3297
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3298 3299 3300
	sysctl_tcp_wmem[1] = 16*1024;
	sysctl_tcp_wmem[2] = max(64*1024, max_share);

3301
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3302 3303
	sysctl_tcp_rmem[1] = 87380;
	sysctl_tcp_rmem[2] = max(87380, max_share);
L
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	printk(KERN_INFO "TCP: Hash tables configured "
3306 3307
	       "(established %u bind %u)\n",
	       tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3308 3309

	tcp_register_congestion_control(&tcp_reno);
3310 3311 3312 3313 3314 3315 3316 3317 3318

	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
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}