tcp.c 80.1 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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#define pr_fmt(fmt) "TCP: " fmt

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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>
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#include <net/inet_common.h>
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#include <net/tcp.h>
#include <net/xfrm.h>
#include <net/ip.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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#include <net/busy_poll.h>
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int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
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int sysctl_tcp_min_tso_segs __read_mostly = 2;

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int sysctl_tcp_autocorking __read_mostly = 1;

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struct percpu_counter tcp_orphan_count;
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EXPORT_SYMBOL_GPL(tcp_orphan_count);

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long sysctl_tcp_mem[3] __read_mostly;
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int sysctl_tcp_wmem[3] __read_mostly;
int sysctl_tcp_rmem[3] __read_mostly;
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EXPORT_SYMBOL(sysctl_tcp_mem);
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EXPORT_SYMBOL(sysctl_tcp_rmem);
EXPORT_SYMBOL(sysctl_tcp_wmem);

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atomic_long_t tcp_memory_allocated;	/* Current allocated memory. */
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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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/* Address-family independent initialization for a tcp_sock.
 *
 * NOTE: A lot of things set to zero explicitly by call to
 *       sk_alloc() so need not be done here.
 */
void tcp_init_sock(struct sock *sk)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct tcp_sock *tp = tcp_sk(sk);

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	__skb_queue_head_init(&tp->out_of_order_queue);
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	tcp_init_xmit_timers(sk);
	tcp_prequeue_init(tp);
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	INIT_LIST_HEAD(&tp->tsq_node);
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	icsk->icsk_rto = TCP_TIMEOUT_INIT;
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	tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
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	/* So many TCP implementations out there (incorrectly) count the
	 * initial SYN frame in their delayed-ACK and congestion control
	 * algorithms that we must have the following bandaid to talk
	 * efficiently to them.  -DaveM
	 */
	tp->snd_cwnd = TCP_INIT_CWND;

	/* See draft-stevens-tcpca-spec-01 for discussion of the
	 * initialization of these values.
	 */
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
	tp->snd_cwnd_clamp = ~0;
	tp->mss_cache = TCP_MSS_DEFAULT;

	tp->reordering = sysctl_tcp_reordering;
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	tcp_enable_early_retrans(tp);
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	tcp_assign_congestion_control(sk);
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	tp->tsoffset = 0;

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	sk->sk_state = TCP_CLOSE;

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

	icsk->icsk_sync_mss = tcp_sync_mss;

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

	local_bh_disable();
	sock_update_memcg(sk);
	sk_sockets_allocated_inc(sk);
	local_bh_enable();
}
EXPORT_SYMBOL(tcp_init_sock);

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static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb)
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{
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	if (sk->sk_tsflags) {
		struct skb_shared_info *shinfo = skb_shinfo(skb);
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		sock_tx_timestamp(sk, &shinfo->tx_flags);
		if (shinfo->tx_flags & SKBTX_ANY_TSTAMP)
			shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
	}
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}

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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;
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	const struct tcp_sock *tp = tcp_sk(sk);
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	sock_rps_record_flow(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;

	/*
	 * 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 or passive Fast Open socket? */
	if (sk->sk_state != TCP_SYN_SENT &&
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	    (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk)) {
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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)) {
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			if (sk_stream_is_writeable(sk)) {
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				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,
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				 * IO signal will be lost. Memory barrier
				 * pairs with the input side.
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				 */
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				smp_mb__after_atomic();
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				if (sk_stream_is_writeable(sk))
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					mask |= POLLOUT | POLLWRNORM;
			}
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		} else
			mask |= POLLOUT | POLLWRNORM;
L
Linus Torvalds 已提交
532 533 534 535

		if (tp->urg_data & TCP_URG_VALID)
			mask |= POLLPRI;
	}
T
Tom Marshall 已提交
536 537
	/* This barrier is coupled with smp_wmb() in tcp_reset() */
	smp_rmb();
538
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
T
Tom Marshall 已提交
539 540
		mask |= POLLERR;

L
Linus Torvalds 已提交
541 542
	return mask;
}
E
Eric Dumazet 已提交
543
EXPORT_SYMBOL(tcp_poll);
L
Linus Torvalds 已提交
544 545 546 547 548

int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int answ;
E
Eric Dumazet 已提交
549
	bool slow;
L
Linus Torvalds 已提交
550 551 552 553 554 555

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

E
Eric Dumazet 已提交
556
		slow = lock_sock_fast(sk);
L
Linus Torvalds 已提交
557 558 559 560 561 562
		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)) {
563

L
Linus Torvalds 已提交
564 565
			answ = tp->rcv_nxt - tp->copied_seq;

E
Eric Dumazet 已提交
566 567 568
			/* Subtract 1, if FIN was received */
			if (answ && sock_flag(sk, SOCK_DONE))
				answ--;
L
Linus Torvalds 已提交
569 570
		} else
			answ = tp->urg_seq - tp->copied_seq;
E
Eric Dumazet 已提交
571
		unlock_sock_fast(sk, slow);
L
Linus Torvalds 已提交
572 573 574 575 576 577 578 579 580 581 582 583 584
		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;
585 586 587 588 589 590 591 592 593
	case SIOCOUTQNSD:
		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_nxt;
		break;
L
Linus Torvalds 已提交
594 595
	default:
		return -ENOIOCTLCMD;
596
	}
L
Linus Torvalds 已提交
597 598 599

	return put_user(answ, (int __user *)arg);
}
E
Eric Dumazet 已提交
600
EXPORT_SYMBOL(tcp_ioctl);
L
Linus Torvalds 已提交
601 602 603

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
604
	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
L
Linus Torvalds 已提交
605 606 607
	tp->pushed_seq = tp->write_seq;
}

E
Eric Dumazet 已提交
608
static inline bool forced_push(const struct tcp_sock *tp)
L
Linus Torvalds 已提交
609 610 611 612
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

613
static void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
614
{
615
	struct tcp_sock *tp = tcp_sk(sk);
616 617 618 619
	struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);

	skb->csum    = 0;
	tcb->seq     = tcb->end_seq = tp->write_seq;
E
Eric Dumazet 已提交
620
	tcb->tcp_flags = TCPHDR_ACK;
621
	tcb->sacked  = 0;
622
	__skb_header_release(skb);
623
	tcp_add_write_queue_tail(sk, skb);
624 625
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
626
	if (tp->nonagle & TCP_NAGLE_PUSH)
627
		tp->nonagle &= ~TCP_NAGLE_PUSH;
L
Linus Torvalds 已提交
628 629
}

630
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
631
{
I
Ilpo Järvinen 已提交
632
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
633 634 635
		tp->snd_up = tp->write_seq;
}

E
Eric Dumazet 已提交
636
/* If a not yet filled skb is pushed, do not send it if
637
 * we have data packets in Qdisc or NIC queues :
E
Eric Dumazet 已提交
638 639 640 641
 * Because TX completion will happen shortly, it gives a chance
 * to coalesce future sendmsg() payload into this skb, without
 * need for a timer, and with no latency trade off.
 * As packets containing data payload have a bigger truesize
642 643 644
 * than pure acks (dataless) packets, the last checks prevent
 * autocorking if we only have an ACK in Qdisc/NIC queues,
 * or if TX completion was delayed after we processed ACK packet.
E
Eric Dumazet 已提交
645 646 647
 */
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
				int size_goal)
L
Linus Torvalds 已提交
648
{
E
Eric Dumazet 已提交
649 650
	return skb->len < size_goal &&
	       sysctl_tcp_autocorking &&
651
	       skb != tcp_write_queue_head(sk) &&
E
Eric Dumazet 已提交
652 653 654 655 656 657 658 659
	       atomic_read(&sk->sk_wmem_alloc) > skb->truesize;
}

static void tcp_push(struct sock *sk, int flags, int mss_now,
		     int nonagle, int size_goal)
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
660

E
Eric Dumazet 已提交
661 662
	if (!tcp_send_head(sk))
		return;
663

E
Eric Dumazet 已提交
664 665 666 667 668 669 670 671 672 673 674 675 676
	skb = tcp_write_queue_tail(sk);
	if (!(flags & MSG_MORE) || forced_push(tp))
		tcp_mark_push(tp, skb);

	tcp_mark_urg(tp, flags);

	if (tcp_should_autocork(sk, skb, size_goal)) {

		/* avoid atomic op if TSQ_THROTTLED bit is already set */
		if (!test_bit(TSQ_THROTTLED, &tp->tsq_flags)) {
			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
			set_bit(TSQ_THROTTLED, &tp->tsq_flags);
		}
677 678 679 680 681
		/* It is possible TX completion already happened
		 * before we set TSQ_THROTTLED.
		 */
		if (atomic_read(&sk->sk_wmem_alloc) > skb->truesize)
			return;
L
Linus Torvalds 已提交
682
	}
E
Eric Dumazet 已提交
683 684 685 686 687

	if (flags & MSG_MORE)
		nonagle = TCP_NAGLE_CORK;

	__tcp_push_pending_frames(sk, mss_now, nonagle);
L
Linus Torvalds 已提交
688 689
}

690 691
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
692 693
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
694
	int ret;
J
Jens Axboe 已提交
695

696 697
	ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
			      tss->flags);
698 699 700
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
701 702 703 704 705 706 707
}

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,
708
		.count	  = tss->len,
J
Jens Axboe 已提交
709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739
	};

	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;

740
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
741 742 743 744 745 746 747 748 749 750
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

751
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789
	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;

790 791
		if (!timeo)
			break;
J
Jens Axboe 已提交
792 793 794 795
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
796
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
797 798 799 800 801 802 803 804 805 806 807
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
808
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
809

810
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
811 812 813 814 815 816 817 818
{
	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) {
819
		if (sk_wmem_schedule(sk, skb->truesize)) {
820
			skb_reserve(skb, sk->sk_prot->max_header);
821 822 823 824
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
E
Eric Dumazet 已提交
825
			skb->reserved_tailroom = skb->end - skb->tail - size;
826 827 828 829
			return skb;
		}
		__kfree_skb(skb);
	} else {
830
		sk->sk_prot->enter_memory_pressure(sk);
831 832 833 834 835
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
836 837 838 839
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
840
	u32 new_size_goal, size_goal;
E
Eric Dumazet 已提交
841 842 843 844

	if (!large_allowed || !sk_can_gso(sk))
		return mss_now;

845 846
	/* Note : tcp_tso_autosize() will eventually split this later */
	new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
E
Eric Dumazet 已提交
847 848 849 850 851 852 853 854 855
	new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);

	/* We try hard to avoid divides here */
	size_goal = tp->gso_segs * mss_now;
	if (unlikely(new_size_goal < size_goal ||
		     new_size_goal >= size_goal + mss_now)) {
		tp->gso_segs = min_t(u16, new_size_goal / mss_now,
				     sk->sk_gso_max_segs);
		size_goal = tp->gso_segs * mss_now;
I
Ilpo Järvinen 已提交
856 857
	}

E
Eric Dumazet 已提交
858
	return max(size_goal, mss_now);
I
Ilpo Järvinen 已提交
859 860 861 862 863 864 865 866 867 868 869 870
}

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;
}

871 872
static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
				size_t size, int flags)
L
Linus Torvalds 已提交
873 874
{
	struct tcp_sock *tp = tcp_sk(sk);
875
	int mss_now, size_goal;
L
Linus Torvalds 已提交
876 877 878 879
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

880 881 882 883 884 885
	/* Wait for a connection to finish. One exception is TCP Fast Open
	 * (passive side) where data is allowed to be sent before a connection
	 * is fully established.
	 */
	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
	    !tcp_passive_fastopen(sk)) {
L
Linus Torvalds 已提交
886 887
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_err;
888
	}
L
Linus Torvalds 已提交
889 890 891

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

I
Ilpo Järvinen 已提交
892
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
893 894 895 896
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
897
		goto out_err;
L
Linus Torvalds 已提交
898

899
	while (size > 0) {
900
		struct sk_buff *skb = tcp_write_queue_tail(sk);
901 902
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
903

904
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
905 906 907 908
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

909
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
L
Linus Torvalds 已提交
910 911 912
			if (!skb)
				goto wait_for_memory;

913
			skb_entail(sk, skb);
914
			copy = size_goal;
L
Linus Torvalds 已提交
915 916 917 918 919 920 921 922 923 924 925
		}

		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;
		}
926
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
927
			goto wait_for_memory;
928

L
Linus Torvalds 已提交
929
		if (can_coalesce) {
E
Eric Dumazet 已提交
930
			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
931 932 933 934
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}
935
		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
936

L
Linus Torvalds 已提交
937 938 939 940
		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
941
		sk_mem_charge(sk, copy);
942
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
943 944
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
945
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
946 947

		if (!copied)
E
Eric Dumazet 已提交
948
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
949 950

		copied += copy;
951
		offset += copy;
952 953
		if (!(size -= copy)) {
			tcp_tx_timestamp(sk, skb);
L
Linus Torvalds 已提交
954
			goto out;
955
		}
L
Linus Torvalds 已提交
956

957
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
958 959 960 961
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
962
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
963
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
964 965 966 967 968 969
			tcp_push_one(sk, mss_now);
		continue;

wait_for_sndbuf:
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
E
Eric Dumazet 已提交
970 971
		tcp_push(sk, flags & ~MSG_MORE, mss_now,
			 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
972 973 974 975

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

I
Ilpo Järvinen 已提交
976
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
977 978 979
	}

out:
980
	if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
E
Eric Dumazet 已提交
981
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
L
Linus Torvalds 已提交
982 983 984 985 986 987 988 989 990
	return copied;

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

991 992
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
993 994 995 996
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
997
	    !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
998 999
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
1000 1001

	lock_sock(sk);
1002
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
1003 1004 1005
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
1006
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
1007

1008
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
1009
{
1010
	const struct tcp_sock *tp = tcp_sk(sk);
1011
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
1012

K
Krishna Kumar 已提交
1013
	if (sg) {
1014 1015 1016 1017 1018 1019
		if (sk_can_gso(sk)) {
			/* Small frames wont use a full page:
			 * Payload will immediately follow tcp header.
			 */
			tmp = SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
		} else {
1020 1021 1022 1023 1024 1025 1026
			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
1027 1028 1029 1030

	return tmp;
}

1031 1032
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
1033
	if (tp->fastopen_req) {
1034 1035 1036 1037 1038
		kfree(tp->fastopen_req);
		tp->fastopen_req = NULL;
	}
}

1039 1040
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
				int *copied, size_t size)
1041 1042 1043 1044 1045 1046
{
	struct tcp_sock *tp = tcp_sk(sk);
	int err, flags;

	if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
		return -EOPNOTSUPP;
1047
	if (tp->fastopen_req)
1048 1049 1050 1051
		return -EALREADY; /* Another Fast Open is in progress */

	tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
				   sk->sk_allocation);
1052
	if (unlikely(!tp->fastopen_req))
1053 1054
		return -ENOBUFS;
	tp->fastopen_req->data = msg;
1055
	tp->fastopen_req->size = size;
1056 1057 1058 1059

	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
	err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
				    msg->msg_namelen, flags);
1060
	*copied = tp->fastopen_req->copied;
1061 1062 1063 1064
	tcp_free_fastopen_req(tp);
	return err;
}

1065
int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
L
Linus Torvalds 已提交
1066 1067 1068
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1069 1070
	int flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0;
1071
	bool sg;
L
Linus Torvalds 已提交
1072 1073 1074 1075 1076
	long timeo;

	lock_sock(sk);

	flags = msg->msg_flags;
1077
	if (flags & MSG_FASTOPEN) {
1078
		err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1079 1080 1081 1082 1083 1084
		if (err == -EINPROGRESS && copied_syn > 0)
			goto out;
		else if (err)
			goto out_err;
	}

L
Linus Torvalds 已提交
1085 1086
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

1087 1088 1089 1090 1091 1092
	/* Wait for a connection to finish. One exception is TCP Fast Open
	 * (passive side) where data is allowed to be sent before a connection
	 * is fully established.
	 */
	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
	    !tcp_passive_fastopen(sk)) {
L
Linus Torvalds 已提交
1093
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1094
			goto do_error;
1095
	}
L
Linus Torvalds 已提交
1096

P
Pavel Emelyanov 已提交
1097 1098 1099
	if (unlikely(tp->repair)) {
		if (tp->repair_queue == TCP_RECV_QUEUE) {
			copied = tcp_send_rcvq(sk, msg, size);
1100
			goto out_nopush;
P
Pavel Emelyanov 已提交
1101 1102 1103 1104 1105 1106 1107 1108 1109
		}

		err = -EINVAL;
		if (tp->repair_queue == TCP_NO_QUEUE)
			goto out_err;

		/* 'common' sending to sendq */
	}

L
Linus Torvalds 已提交
1110 1111 1112
	/* This should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

I
Ilpo Järvinen 已提交
1113
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1114 1115 1116 1117 1118 1119

	/* Ok commence sending. */
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1120
		goto out_err;
L
Linus Torvalds 已提交
1121

1122
	sg = !!(sk->sk_route_caps & NETIF_F_SG);
K
Krishna Kumar 已提交
1123

A
Al Viro 已提交
1124
	while (msg_data_left(msg)) {
1125 1126
		int copy = 0;
		int max = size_goal;
L
Linus Torvalds 已提交
1127

1128 1129 1130 1131 1132
		skb = tcp_write_queue_tail(sk);
		if (tcp_send_head(sk)) {
			if (skb->ip_summed == CHECKSUM_NONE)
				max = mss_now;
			copy = max - skb->len;
1133
		}
L
Linus Torvalds 已提交
1134

1135
		if (copy <= 0) {
L
Linus Torvalds 已提交
1136
new_segment:
1137 1138 1139 1140 1141
			/* Allocate new segment. If the interface is SG,
			 * allocate skb fitting to single page.
			 */
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;
L
Linus Torvalds 已提交
1142

1143 1144 1145 1146 1147
			skb = sk_stream_alloc_skb(sk,
						  select_size(sk, sg),
						  sk->sk_allocation);
			if (!skb)
				goto wait_for_memory;
L
Linus Torvalds 已提交
1148

1149 1150 1151 1152 1153
			/*
			 * Check whether we can use HW checksum.
			 */
			if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
				skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
1154

1155 1156 1157
			skb_entail(sk, skb);
			copy = size_goal;
			max = size_goal;
1158

1159 1160 1161 1162 1163 1164 1165
			/* All packets are restored as if they have
			 * already been sent. skb_mstamp isn't set to
			 * avoid wrong rtt estimation.
			 */
			if (tp->repair)
				TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
		}
L
Linus Torvalds 已提交
1166

1167
		/* Try to append data to the end of skb. */
A
Al Viro 已提交
1168 1169
		if (copy > msg_data_left(msg))
			copy = msg_data_left(msg);
1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184

		/* Where to copy to? */
		if (skb_availroom(skb) > 0) {
			/* We have some space in skb head. Superb! */
			copy = min_t(int, copy, skb_availroom(skb));
			err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
			if (err)
				goto do_fault;
		} else {
			bool merge = true;
			int i = skb_shinfo(skb)->nr_frags;
			struct page_frag *pfrag = sk_page_frag(sk);

			if (!sk_page_frag_refill(sk, pfrag))
				goto wait_for_memory;
1185

1186 1187 1188 1189 1190
			if (!skb_can_coalesce(skb, i, pfrag->page,
					      pfrag->offset)) {
				if (i == MAX_SKB_FRAGS || !sg) {
					tcp_mark_push(tp, skb);
					goto new_segment;
L
Linus Torvalds 已提交
1191
				}
1192
				merge = false;
L
Linus Torvalds 已提交
1193 1194
			}

1195 1196 1197 1198
			copy = min_t(int, copy, pfrag->size - pfrag->offset);

			if (!sk_wmem_schedule(sk, copy))
				goto wait_for_memory;
L
Linus Torvalds 已提交
1199

1200 1201 1202 1203 1204 1205
			err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
						       pfrag->page,
						       pfrag->offset,
						       copy);
			if (err)
				goto do_error;
L
Linus Torvalds 已提交
1206

1207 1208 1209 1210 1211 1212 1213
			/* Update the skb. */
			if (merge) {
				skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
			} else {
				skb_fill_page_desc(skb, i, pfrag->page,
						   pfrag->offset, copy);
				get_page(pfrag->page);
1214
			}
1215 1216 1217 1218 1219 1220 1221 1222 1223
			pfrag->offset += copy;
		}

		if (!copied)
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;

		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
1224

1225
		copied += copy;
A
Al Viro 已提交
1226
		if (!msg_data_left(msg)) {
1227 1228 1229
			tcp_tx_timestamp(sk, skb);
			goto out;
		}
L
Linus Torvalds 已提交
1230

1231
		if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1232 1233
			continue;

1234 1235 1236 1237 1238 1239 1240
		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
		} else if (skb == tcp_send_head(sk))
			tcp_push_one(sk, mss_now);
		continue;

L
Linus Torvalds 已提交
1241
wait_for_sndbuf:
1242
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
L
Linus Torvalds 已提交
1243
wait_for_memory:
1244 1245 1246
		if (copied)
			tcp_push(sk, flags & ~MSG_MORE, mss_now,
				 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
1247

1248 1249
		if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
			goto do_error;
L
Linus Torvalds 已提交
1250

1251
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1252 1253 1254
	}

out:
1255
	if (copied)
E
Eric Dumazet 已提交
1256
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1257
out_nopush:
L
Linus Torvalds 已提交
1258
	release_sock(sk);
1259
	return copied + copied_syn;
L
Linus Torvalds 已提交
1260 1261 1262

do_fault:
	if (!skb->len) {
1263 1264 1265 1266 1267
		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);
1268
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1269 1270 1271
	}

do_error:
1272
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1273 1274 1275 1276 1277 1278
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1279
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1280 1281 1282 1283 1284 1285

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

1286
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309
{
	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))
A
Al Viro 已提交
1310
				err = memcpy_to_msg(msg, &c, 1);
L
Linus Torvalds 已提交
1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
			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;
}

P
Pavel Emelyanov 已提交
1330 1331 1332 1333 1334 1335 1336 1337
static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
{
	struct sk_buff *skb;
	int copied = 0, err = 0;

	/* XXX -- need to support SO_PEEK_OFF */

	skb_queue_walk(&sk->sk_write_queue, skb) {
1338
		err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
P
Pavel Emelyanov 已提交
1339 1340 1341 1342 1343 1344 1345 1346 1347
		if (err)
			break;

		copied += skb->len;
	}

	return err ?: copied;
}

L
Linus Torvalds 已提交
1348 1349 1350 1351 1352 1353
/* 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.
 */
1354
static void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1355 1356
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1357
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1358 1359 1360

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

1361
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1362
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1363
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1364

1365 1366
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1367 1368
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1369
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1370
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1371
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1372 1373 1374 1375 1376 1377
		    /*
		     * 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.
		     */
1378 1379 1380 1381 1382
		    (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)))
E
Eric Dumazet 已提交
1383
			time_to_ack = true;
L
Linus Torvalds 已提交
1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404
	}

	/* 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)
E
Eric Dumazet 已提交
1405
				time_to_ack = true;
L
Linus Torvalds 已提交
1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
		}
	}
	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);

1417
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1418 1419 1420 1421 1422

	/* 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
1423
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1424 1425 1426 1427 1428 1429
	local_bh_enable();

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

1430
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
L
Linus Torvalds 已提交
1431 1432 1433 1434
{
	struct sk_buff *skb;
	u32 offset;

1435
	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
L
Linus Torvalds 已提交
1436
		offset = seq - TCP_SKB_CB(skb)->seq;
1437
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1438
			offset--;
1439
		if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
L
Linus Torvalds 已提交
1440 1441 1442
			*off = offset;
			return skb;
		}
1443 1444 1445 1446
		/* This looks weird, but this can happen if TCP collapsing
		 * splitted a fat GRO packet, while we released socket lock
		 * in skb_splice_bits()
		 */
D
Dan Williams 已提交
1447
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475
	}
	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) {
1476 1477
			int used;
			size_t len;
L
Linus Torvalds 已提交
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488

			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);
1489
			if (used <= 0) {
1490 1491 1492 1493
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1494 1495 1496 1497
				seq += used;
				copied += used;
				offset += used;
			}
1498
			/* If recv_actor drops the lock (e.g. TCP splice
1499 1500 1501 1502
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1503 1504
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1505
				break;
1506 1507 1508 1509 1510
			/* TCP coalescing might have appended data to the skb.
			 * Try to splice more frags
			 */
			if (offset + 1 != skb->len)
				continue;
L
Linus Torvalds 已提交
1511
		}
1512
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
D
Dan Williams 已提交
1513
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1514 1515 1516
			++seq;
			break;
		}
D
Dan Williams 已提交
1517
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1518 1519
		if (!desc->count)
			break;
1520
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1521 1522 1523 1524 1525 1526
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1527 1528
	if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
1529
		tcp_cleanup_rbuf(sk, copied);
1530
	}
L
Linus Torvalds 已提交
1531 1532
	return copied;
}
E
Eric Dumazet 已提交
1533
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1534 1535 1536 1537 1538 1539 1540 1541 1542

/*
 *	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.
 */

1543 1544
int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
		int flags, int *addr_len)
L
Linus Torvalds 已提交
1545 1546 1547 1548 1549 1550 1551 1552 1553 1554
{
	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;
1555
	struct sk_buff *skb;
I
Ilpo Järvinen 已提交
1556
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1557

1558
	if (unlikely(flags & MSG_ERRQUEUE))
1559
		return inet_recv_error(sk, msg, len, addr_len);
1560

1561 1562 1563
	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
	    (sk->sk_state == TCP_ESTABLISHED))
		sk_busy_loop(sk, nonblock);
1564

L
Linus Torvalds 已提交
1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
	lock_sock(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;

P
Pavel Emelyanov 已提交
1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591
	if (unlikely(tp->repair)) {
		err = -EPERM;
		if (!(flags & MSG_PEEK))
			goto out;

		if (tp->repair_queue == TCP_SEND_QUEUE)
			goto recv_sndq;

		err = -EINVAL;
		if (tp->repair_queue == TCP_NO_QUEUE)
			goto out;

		/* 'common' recv queue MSG_PEEK-ing */
	}

L
Linus Torvalds 已提交
1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614
	seq = &tp->copied_seq;
	if (flags & MSG_PEEK) {
		peek_seq = tp->copied_seq;
		seq = &peek_seq;
	}

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

	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. */

1615
		skb_queue_walk(&sk->sk_receive_queue, skb) {
L
Linus Torvalds 已提交
1616 1617 1618
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1619
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1620 1621 1622
				 "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
1623
				break;
1624

L
Linus Torvalds 已提交
1625
			offset = *seq - TCP_SKB_CB(skb)->seq;
1626
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1627 1628 1629
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1630
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1631
				goto found_fin_ok;
J
Joe Perches 已提交
1632 1633 1634
			WARN(!(flags & MSG_PEEK),
			     "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
			     *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
1635
		}
L
Linus Torvalds 已提交
1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646

		/* 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 ||
1647
			    signal_pending(current))
L
Linus Torvalds 已提交
1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682
				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;
			}
		}

1683
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1684

1685
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1686 1687 1688 1689
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
1690
				tp->ucopy.msg = msg;
L
Linus Torvalds 已提交
1691 1692 1693 1694
			}

			tp->ucopy.len = len;

1695 1696
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723

			/* 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.
			 */
1724
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742
				goto do_prequeue;

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

		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
		} else
			sk_wait_data(sk, &timeo);

		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

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

			if (tp->rcv_nxt == tp->copied_seq &&
1749
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1750 1751 1752 1753
do_prequeue:
				tcp_prequeue_process(sk);

				if ((chunk = len - tp->ucopy.len) != 0) {
1754
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1755 1756 1757 1758 1759
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1760 1761
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1762 1763 1764
			net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
					    current->comm,
					    task_pid_nr(current));
L
Linus Torvalds 已提交
1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781
			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
1782
						urg_hole++;
L
Linus Torvalds 已提交
1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
1794
			err = skb_copy_datagram_msg(skb, offset, msg, used);
D
Dan Williams 已提交
1795 1796 1797 1798 1799
			if (err) {
				/* Exception. Bailout! */
				if (!copied)
					copied = -EFAULT;
				break;
L
Linus Torvalds 已提交
1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811
			}
		}

		*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;
1812
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1813 1814 1815 1816
		}
		if (used + offset < skb->len)
			continue;

1817
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1818
			goto found_fin_ok;
D
Dan Williams 已提交
1819 1820
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1821 1822 1823 1824 1825
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
D
Dan Williams 已提交
1826 1827
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1828 1829 1830 1831
		break;
	} while (len > 0);

	if (user_recv) {
1832
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1833 1834 1835 1836 1837 1838 1839
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1840
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854
				len -= chunk;
				copied += chunk;
			}
		}

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

	/* 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. */
1855
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1856 1857 1858 1859 1860 1861 1862 1863 1864

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
1865
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1866
	goto out;
P
Pavel Emelyanov 已提交
1867 1868 1869 1870

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
1871
}
E
Eric Dumazet 已提交
1872
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
1873

I
Ilpo Järvinen 已提交
1874 1875 1876 1877 1878 1879 1880
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
1881
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1882 1883 1884 1885
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1886
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1887 1888 1889 1890

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1891
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1892 1893
		/* fall through */
	default:
1894
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1895
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1896 1897 1898 1899 1900 1901 1902 1903
	}

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

#ifdef STATE_TRACE
1904
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1905 1906 1907 1908
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1909 1910 1911 1912 1913 1914 1915
/*
 *	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.
 */

1916
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1917
  /* current state:        new state:      action:	*/
1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930
  [0 /* (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,
  [TCP_NEW_SYN_RECV]	= TCP_CLOSE,	/* should not happen ! */
L
Linus Torvalds 已提交
1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944
};

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
1945
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965
 */

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
1966
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
1967

A
Arun Sharma 已提交
1968 1969 1970 1971 1972 1973 1974
bool tcp_check_oom(struct sock *sk, int shift)
{
	bool too_many_orphans, out_of_socket_memory;

	too_many_orphans = tcp_too_many_orphans(sk, shift);
	out_of_socket_memory = tcp_out_of_memory(sk);

1975 1976 1977 1978
	if (too_many_orphans)
		net_info_ratelimited("too many orphaned sockets\n");
	if (out_of_socket_memory)
		net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
A
Arun Sharma 已提交
1979 1980 1981
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
1982 1983 1984 1985
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
1986
	int state;
L
Linus Torvalds 已提交
1987 1988 1989 1990 1991 1992 1993 1994

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

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

		/* Special case. */
1995
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
1996 1997 1998 1999 2000 2001 2002 2003 2004

		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) {
2005 2006 2007 2008
		u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;

		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
			len--;
L
Linus Torvalds 已提交
2009 2010 2011 2012
		data_was_unread += len;
		__kfree_skb(skb);
	}

2013
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2014

2015 2016 2017 2018
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2019 2020 2021 2022 2023 2024
	/* 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
2025
	 */
P
Pavel Emelyanov 已提交
2026 2027 2028
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2029
		/* Unread data was tossed, zap the connection. */
2030
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2031
		tcp_set_state(sk, TCP_CLOSE);
2032
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2033 2034 2035
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2036
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061
	} 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
2062 2063 2064 2065
		 * XXX (TFO) - To start off we don't support SYN+ACK+FIN
		 * in a single packet! (May consider it later but will
		 * probably need API support or TCP_CORK SYN-ACK until
		 * data is written and socket is closed.)
L
Linus Torvalds 已提交
2066 2067 2068 2069 2070 2071 2072
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2073 2074 2075 2076
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2077 2078 2079 2080 2081 2082 2083 2084 2085
	/* 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);
2086
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2087

H
Herbert Xu 已提交
2088 2089
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2090 2091 2092
	/* 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
2093 2094 2095 2096

	/*	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.
2097
	 *	We use a 1 minute timeout (about the same as BSD) then kill
L
Linus Torvalds 已提交
2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112
	 *	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);
2113 2114
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2115
		} else {
2116
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2117 2118

			if (tmo > TCP_TIMEWAIT_LEN) {
2119 2120
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2121 2122 2123 2124 2125 2126 2127
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2128
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2129
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2130 2131
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2132 2133
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2134 2135 2136
		}
	}

2137 2138 2139 2140 2141 2142
	if (sk->sk_state == TCP_CLOSE) {
		struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
		/* We could get here with a non-NULL req if the socket is
		 * aborted (e.g., closed with unread data) before 3WHS
		 * finishes.
		 */
2143
		if (req)
2144
			reqsk_fastopen_remove(sk, req, false);
2145
		inet_csk_destroy_sock(sk);
2146
	}
L
Linus Torvalds 已提交
2147 2148 2149 2150 2151 2152 2153
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2154
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2155 2156 2157

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

E
Eric Dumazet 已提交
2158
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2159 2160 2161 2162 2163 2164 2165 2166 2167
{
	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);
2168
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2169 2170 2171 2172 2173 2174 2175 2176 2177
	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) {
2178
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2179 2180
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2181 2182 2183
	} 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
2184
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2185 2186 2187 2188 2189 2190 2191 2192 2193
		 * 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);
2194
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2195 2196
	__skb_queue_purge(&tp->out_of_order_queue);

E
Eric Dumazet 已提交
2197
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2198 2199 2200 2201 2202 2203

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

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
2204
	tp->srtt_us = 0;
L
Linus Torvalds 已提交
2205 2206
	if ((tp->write_seq += tp->max_window + 2) == 0)
		tp->write_seq = 1;
2207
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2208
	tp->snd_cwnd = 2;
2209
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2210
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2211
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2212
	tp->snd_cwnd_cnt = 0;
2213
	tp->window_clamp = 0;
2214
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2215
	tcp_clear_retrans(tp);
2216
	inet_csk_delack_init(sk);
2217
	tcp_init_send_head(sk);
2218
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2219 2220
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2221
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2222 2223 2224 2225

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2226
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2227

2228 2229 2230 2231 2232 2233 2234
void tcp_sock_destruct(struct sock *sk)
{
	inet_sock_destruct(sk);

	kfree(inet_csk(sk)->icsk_accept_queue.fastopenq);
}

E
Eric Dumazet 已提交
2235
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2236
{
2237
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2238 2239 2240
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2241 2242
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2243
{
2244
	struct tcp_repair_opt opt;
2245

2246 2247
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2248 2249 2250
			return -EFAULT;

		optbuf++;
2251
		len -= sizeof(opt);
2252

2253 2254 2255
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2256
			break;
2257
		case TCPOPT_WINDOW:
2258 2259 2260 2261 2262 2263
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2264

2265 2266 2267 2268
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2269 2270
			break;
		case TCPOPT_SACK_PERM:
2271 2272 2273
			if (opt.opt_val != 0)
				return -EINVAL;

2274 2275 2276 2277 2278
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2279 2280 2281
			if (opt.opt_val != 0)
				return -EINVAL;

2282 2283 2284 2285 2286 2287 2288 2289
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

L
Linus Torvalds 已提交
2290 2291 2292
/*
 *	Socket option code for TCP.
 */
2293
static int do_tcp_setsockopt(struct sock *sk, int level,
2294
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2295 2296
{
	struct tcp_sock *tp = tcp_sk(sk);
2297
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2298 2299 2300
	int val;
	int err = 0;

2301 2302 2303
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2304 2305 2306 2307 2308 2309
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2310
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2311 2312 2313 2314 2315
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2316
		err = tcp_set_congestion_control(sk, name);
2317 2318 2319
		release_sock(sk);
		return err;
	}
2320 2321 2322
	default:
		/* fallthru */
		break;
2323
	}
2324

L
Linus Torvalds 已提交
2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337
	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 */
2338
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355
			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;
2356
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2357 2358 2359 2360 2361
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2362 2363 2364 2365 2366 2367 2368
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2369 2370 2371
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
2372
		else {
A
Andreas Petlund 已提交
2373
			tp->thin_dupack = val;
Y
Yuchung Cheng 已提交
2374 2375
			if (tp->thin_dupack)
				tcp_disable_early_retrans(tp);
2376
		}
A
Andreas Petlund 已提交
2377 2378
		break;

P
Pavel Emelyanov 已提交
2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414
	case TCP_REPAIR:
		if (!tcp_can_repair_sock(sk))
			err = -EPERM;
		else if (val == 1) {
			tp->repair = 1;
			sk->sk_reuse = SK_FORCE_REUSE;
			tp->repair_queue = TCP_NO_QUEUE;
		} else if (val == 0) {
			tp->repair = 0;
			sk->sk_reuse = SK_NO_REUSE;
			tcp_send_window_probe(sk);
		} else
			err = -EINVAL;

		break;

	case TCP_REPAIR_QUEUE:
		if (!tp->repair)
			err = -EPERM;
		else if (val < TCP_QUEUES_NR)
			tp->repair_queue = val;
		else
			err = -EINVAL;
		break;

	case TCP_QUEUE_SEQ:
		if (sk->sk_state != TCP_CLOSE)
			err = -EPERM;
		else if (tp->repair_queue == TCP_SEND_QUEUE)
			tp->write_seq = val;
		else if (tp->repair_queue == TCP_RECV_QUEUE)
			tp->rcv_nxt = val;
		else
			err = -EINVAL;
		break;

2415 2416 2417 2418
	case TCP_REPAIR_OPTIONS:
		if (!tp->repair)
			err = -EINVAL;
		else if (sk->sk_state == TCP_ESTABLISHED)
2419 2420 2421
			err = tcp_repair_options_est(tp,
					(struct tcp_repair_opt __user *)optval,
					optlen);
2422 2423 2424 2425
		else
			err = -EPERM;
		break;

L
Linus Torvalds 已提交
2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443
	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;
2444
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455
		}
		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))) {
2456
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2457 2458 2459 2460
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2461
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480
			}
		}
		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
2481
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493
		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:
2494 2495 2496 2497
		/* Translate value in seconds to number of retransmits */
		icsk->icsk_accept_queue.rskq_defer_accept =
			secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
					TCP_RTO_MAX / HZ);
L
Linus Torvalds 已提交
2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513
		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) {
2514
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2515
		} else {
2516
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2517 2518
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2519 2520
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2521
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2522
				if (!(val & 1))
2523
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2524 2525 2526 2527
			}
		}
		break;

2528 2529 2530 2531 2532 2533
#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
2534
	case TCP_USER_TIMEOUT:
2535
		/* Cap the max time in ms TCP will retry or probe the window
2536 2537
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2538 2539 2540 2541
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2542
		break;
2543 2544 2545 2546 2547 2548 2549 2550

	case TCP_FASTOPEN:
		if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
		    TCPF_LISTEN)))
			err = fastopen_init_queue(sk, val);
		else
			err = -EINVAL;
		break;
2551 2552 2553 2554 2555 2556
	case TCP_TIMESTAMP:
		if (!tp->repair)
			err = -EPERM;
		else
			tp->tsoffset = val - tcp_time_stamp;
		break;
2557 2558 2559 2560
	case TCP_NOTSENT_LOWAT:
		tp->notsent_lowat = val;
		sk->sk_write_space(sk);
		break;
L
Linus Torvalds 已提交
2561 2562 2563
	default:
		err = -ENOPROTOOPT;
		break;
2564 2565
	}

L
Linus Torvalds 已提交
2566 2567 2568 2569
	release_sock(sk);
	return err;
}

2570
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2571
		   unsigned int optlen)
2572
{
2573
	const struct inet_connection_sock *icsk = inet_csk(sk);
2574 2575 2576 2577 2578 2579

	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
2580
EXPORT_SYMBOL(tcp_setsockopt);
2581 2582

#ifdef CONFIG_COMPAT
2583
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2584
			  char __user *optval, unsigned int optlen)
2585
{
2586 2587 2588
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2589 2590
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2591
EXPORT_SYMBOL(compat_tcp_setsockopt);
2592 2593
#endif

L
Linus Torvalds 已提交
2594
/* Return information about state of tcp endpoint in API format. */
2595
void tcp_get_info(struct sock *sk, struct tcp_info *info)
L
Linus Torvalds 已提交
2596
{
2597
	const struct tcp_sock *tp = tcp_sk(sk);
2598
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2599
	u32 now = tcp_time_stamp;
2600
	u32 rate;
L
Linus Torvalds 已提交
2601 2602 2603 2604

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

	info->tcpi_state = sk->sk_state;
2605
	info->tcpi_ca_state = icsk->icsk_ca_state;
2606
	info->tcpi_retransmits = icsk->icsk_retransmits;
2607
	info->tcpi_probes = icsk->icsk_probes_out;
2608
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2609 2610 2611

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2612
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2613 2614 2615 2616 2617
		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;
2618
	}
L
Linus Torvalds 已提交
2619

E
Eric Dumazet 已提交
2620
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2621
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2622 2623
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2624 2625
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2626

2627 2628
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2629
	info->tcpi_snd_mss = tp->mss_cache;
2630
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2631

2632 2633 2634 2635 2636 2637 2638
	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
2639 2640 2641 2642 2643
	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);
2644
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2645 2646
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2647
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2648
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2649 2650
	info->tcpi_rtt = tp->srtt_us >> 3;
	info->tcpi_rttvar = tp->mdev_us >> 2;
L
Linus Torvalds 已提交
2651 2652 2653 2654 2655 2656 2657 2658 2659
	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;
2660

2661 2662 2663 2664 2665
	rate = READ_ONCE(sk->sk_pacing_rate);
	info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL;

	rate = READ_ONCE(sk->sk_max_pacing_rate);
	info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL;
2666 2667 2668

	spin_lock_bh(&sk->sk_lock.slock);
	info->tcpi_bytes_acked = tp->bytes_acked;
2669
	info->tcpi_bytes_received = tp->bytes_received;
2670
	spin_unlock_bh(&sk->sk_lock.slock);
L
Linus Torvalds 已提交
2671 2672 2673
}
EXPORT_SYMBOL_GPL(tcp_get_info);

2674 2675
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2676
{
2677
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690
	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:
2691
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2692 2693
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2694 2695
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2696 2697 2698 2699 2700 2701 2702 2703
		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
2704
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2705 2706
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2707
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2708 2709
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2710
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2711 2712
		break;
	case TCP_SYNCNT:
2713
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2714 2715 2716 2717 2718 2719 2720
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2721 2722
		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
2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742
		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:
2743
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2744
		break;
2745 2746 2747 2748 2749 2750 2751

	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;
2752
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2753 2754
			return -EFAULT;
		return 0;
2755

2756 2757 2758 2759 2760 2761
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2762

P
Pavel Emelyanov 已提交
2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782
	case TCP_REPAIR:
		val = tp->repair;
		break;

	case TCP_REPAIR_QUEUE:
		if (tp->repair)
			val = tp->repair_queue;
		else
			return -EINVAL;
		break;

	case TCP_QUEUE_SEQ:
		if (tp->repair_queue == TCP_SEND_QUEUE)
			val = tp->write_seq;
		else if (tp->repair_queue == TCP_RECV_QUEUE)
			val = tp->rcv_nxt;
		else
			return -EINVAL;
		break;

2783 2784 2785
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
2786 2787

	case TCP_FASTOPEN:
2788
		if (icsk->icsk_accept_queue.fastopenq)
2789 2790 2791 2792 2793
			val = icsk->icsk_accept_queue.fastopenq->max_qlen;
		else
			val = 0;
		break;

2794 2795 2796
	case TCP_TIMESTAMP:
		val = tcp_time_stamp + tp->tsoffset;
		break;
2797 2798 2799
	case TCP_NOTSENT_LOWAT:
		val = tp->notsent_lowat;
		break;
L
Linus Torvalds 已提交
2800 2801
	default:
		return -ENOPROTOOPT;
2802
	}
L
Linus Torvalds 已提交
2803 2804 2805 2806 2807 2808 2809 2810

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

2811 2812 2813 2814 2815 2816 2817 2818 2819 2820
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
2821
EXPORT_SYMBOL(tcp_getsockopt);
2822 2823

#ifdef CONFIG_COMPAT
2824 2825
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2826
{
2827 2828 2829
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2830 2831
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2832
EXPORT_SYMBOL(compat_tcp_getsockopt);
2833
#endif
L
Linus Torvalds 已提交
2834

2835
#ifdef CONFIG_TCP_MD5SIG
E
Eric Dumazet 已提交
2836
static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2837
static DEFINE_MUTEX(tcp_md5sig_mutex);
E
Eric Dumazet 已提交
2838
static bool tcp_md5sig_pool_populated = false;
2839

2840
static void __tcp_alloc_md5sig_pool(void)
2841 2842 2843 2844
{
	int cpu;

	for_each_possible_cpu(cpu) {
E
Eric Dumazet 已提交
2845 2846
		if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
			struct crypto_hash *hash;
2847

E
Eric Dumazet 已提交
2848 2849 2850 2851 2852
			hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
			if (IS_ERR_OR_NULL(hash))
				return;
			per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
		}
2853
	}
E
Eric Dumazet 已提交
2854 2855
	/* before setting tcp_md5sig_pool_populated, we must commit all writes
	 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2856 2857
	 */
	smp_wmb();
E
Eric Dumazet 已提交
2858
	tcp_md5sig_pool_populated = true;
2859 2860
}

2861
bool tcp_alloc_md5sig_pool(void)
2862
{
E
Eric Dumazet 已提交
2863
	if (unlikely(!tcp_md5sig_pool_populated)) {
2864 2865
		mutex_lock(&tcp_md5sig_mutex);

E
Eric Dumazet 已提交
2866
		if (!tcp_md5sig_pool_populated)
2867 2868 2869
			__tcp_alloc_md5sig_pool();

		mutex_unlock(&tcp_md5sig_mutex);
2870
	}
E
Eric Dumazet 已提交
2871
	return tcp_md5sig_pool_populated;
2872 2873 2874
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
2875 2876 2877 2878 2879 2880 2881 2882 2883

/**
 *	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)
2884
{
E
Eric Dumazet 已提交
2885
	local_bh_disable();
2886

E
Eric Dumazet 已提交
2887 2888 2889 2890 2891
	if (tcp_md5sig_pool_populated) {
		/* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
		smp_rmb();
		return this_cpu_ptr(&tcp_md5sig_pool);
	}
E
Eric Dumazet 已提交
2892 2893 2894 2895
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
2896

2897
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2898
			const struct tcphdr *th)
2899 2900
{
	struct scatterlist sg;
2901
	struct tcphdr hdr;
2902 2903
	int err;

2904 2905 2906 2907
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

2908
	/* options aren't included in the hash */
2909 2910
	sg_init_one(&sg, &hdr, sizeof(hdr));
	err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
2911 2912 2913 2914 2915
	return err;
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
2916
			  const struct sk_buff *skb, unsigned int header_len)
2917 2918 2919 2920
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
	struct hash_desc *desc = &hp->md5_desc;
2921 2922 2923
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
2924
	const struct skb_shared_info *shi = skb_shinfo(skb);
2925
	struct sk_buff *frag_iter;
2926 2927 2928 2929 2930 2931 2932 2933 2934

	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];
E
Eric Dumazet 已提交
2935 2936 2937 2938 2939
		unsigned int offset = f->page_offset;
		struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);

		sg_set_page(&sg, page, skb_frag_size(f),
			    offset_in_page(offset));
E
Eric Dumazet 已提交
2940
		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
2941 2942 2943
			return 1;
	}

2944 2945 2946 2947
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

2948 2949 2950 2951
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

2952
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
2953 2954 2955 2956 2957 2958 2959 2960
{
	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);

2961 2962
#endif

A
Andi Kleen 已提交
2963 2964
void tcp_done(struct sock *sk)
{
2965 2966
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

2967
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
2968
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
2969 2970 2971

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
2972
	if (req)
2973
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
2974 2975 2976 2977 2978 2979 2980 2981 2982 2983

	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);

2984
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
2985 2986 2987 2988

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
2989 2990
	ssize_t ret;

L
Linus Torvalds 已提交
2991 2992
	if (!str)
		return 0;
2993 2994 2995 2996 2997

	ret = kstrtoul(str, 0, &thash_entries);
	if (ret)
		return 0;

L
Linus Torvalds 已提交
2998 2999 3000 3001
	return 1;
}
__setup("thash_entries=", set_thash_entries);

F
Fabian Frederick 已提交
3002
static void __init tcp_init_mem(void)
3003 3004 3005
{
	unsigned long limit = nr_free_buffer_pages() / 8;
	limit = max(limit, 128UL);
3006 3007 3008
	sysctl_tcp_mem[0] = limit / 4 * 3;
	sysctl_tcp_mem[1] = limit;
	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3009 3010
}

L
Linus Torvalds 已提交
3011 3012
void __init tcp_init(void)
{
3013
	unsigned long limit;
3014
	int max_rshare, max_wshare, cnt;
3015
	unsigned int i;
L
Linus Torvalds 已提交
3016

3017
	sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
L
Linus Torvalds 已提交
3018

3019 3020
	percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
	percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3021 3022 3023
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3024
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3025 3026 3027 3028 3029 3030

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3031
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3032
		alloc_large_system_hash("TCP established",
3033
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3034
					thash_entries,
E
Eric Dumazet 已提交
3035
					17, /* one slot per 128 KB of memory */
3036
					0,
L
Linus Torvalds 已提交
3037
					NULL,
3038
					&tcp_hashinfo.ehash_mask,
3039
					0,
3040
					thash_entries ? 0 : 512 * 1024);
E
Eric Dumazet 已提交
3041
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3042
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
E
Eric Dumazet 已提交
3043

3044 3045
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3046
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3047
		alloc_large_system_hash("TCP bind",
3048
					sizeof(struct inet_bind_hashbucket),
3049
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3050
					17, /* one slot per 128 KB of memory */
3051
					0,
3052
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3053
					NULL,
3054
					0,
L
Linus Torvalds 已提交
3055
					64 * 1024);
3056
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3057 3058 3059
	for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
		spin_lock_init(&tcp_hashinfo.bhash[i].lock);
		INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
L
Linus Torvalds 已提交
3060 3061
	}

E
Eric Dumazet 已提交
3062 3063 3064 3065 3066 3067

	cnt = tcp_hashinfo.ehash_mask + 1;

	tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
	sysctl_tcp_max_orphans = cnt / 2;
	sysctl_max_syn_backlog = max(128, cnt / 256);
L
Linus Torvalds 已提交
3068

3069
	tcp_init_mem();
3070
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3071
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3072 3073
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3074

3075
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3076
	sysctl_tcp_wmem[1] = 16*1024;
3077
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3078

3079
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3080
	sysctl_tcp_rmem[1] = 87380;
3081
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3082

3083
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3084
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3085

3086
	tcp_metrics_init();
3087
	BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
E
Eric Dumazet 已提交
3088
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3089
}