tcp.c 83.8 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 <crypto/hash.h>
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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>
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#include <linux/inet_diag.h>
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#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/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 <asm/unaligned.h>
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#include <net/busy_poll.h>
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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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	tp->rtt_min[0].rtt = ~0U;
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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;
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	u64_stats_init(&tp->syncp);
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	tp->reordering = sock_net(sk)->ipv4.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();
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	if (mem_cgroup_sockets_enabled)
		sock_update_memcg(sk);
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	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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		struct tcp_skb_cb *tcb = TCP_SKB_CB(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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		tcb->txstamp_ack = !!(shinfo->tx_flags & SKBTX_ACK_TSTAMP);
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	}
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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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	int state;
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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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	state = sk_state_load(sk);
	if (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
	 */
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	if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
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		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? */
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	if (state != TCP_SYN_SENT &&
	    (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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		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 */
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				sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
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				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);

				/* Race breaker. If space is freed after
				 * wspace test but before the flags are set,
527 528
				 * IO signal will be lost. Memory barrier
				 * pairs with the input side.
L
Linus Torvalds 已提交
529
				 */
530
				smp_mb__after_atomic();
531
				if (sk_stream_is_writeable(sk))
L
Linus Torvalds 已提交
532 533
					mask |= POLLOUT | POLLWRNORM;
			}
534 535
		} else
			mask |= POLLOUT | POLLWRNORM;
L
Linus Torvalds 已提交
536 537 538 539

		if (tp->urg_data & TCP_URG_VALID)
			mask |= POLLPRI;
	}
T
Tom Marshall 已提交
540 541
	/* This barrier is coupled with smp_wmb() in tcp_reset() */
	smp_rmb();
542
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
T
Tom Marshall 已提交
543 544
		mask |= POLLERR;

L
Linus Torvalds 已提交
545 546
	return mask;
}
E
Eric Dumazet 已提交
547
EXPORT_SYMBOL(tcp_poll);
L
Linus Torvalds 已提交
548 549 550 551 552

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
553
	bool slow;
L
Linus Torvalds 已提交
554 555 556 557 558 559

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

E
Eric Dumazet 已提交
560
		slow = lock_sock_fast(sk);
561
		answ = tcp_inq(sk);
E
Eric Dumazet 已提交
562
		unlock_sock_fast(sk, slow);
L
Linus Torvalds 已提交
563 564 565 566 567 568 569 570 571 572 573 574 575
		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;
576 577 578 579 580 581 582 583 584
	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
585 586
	default:
		return -ENOIOCTLCMD;
587
	}
L
Linus Torvalds 已提交
588 589 590

	return put_user(answ, (int __user *)arg);
}
E
Eric Dumazet 已提交
591
EXPORT_SYMBOL(tcp_ioctl);
L
Linus Torvalds 已提交
592 593 594

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
595
	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
L
Linus Torvalds 已提交
596 597 598
	tp->pushed_seq = tp->write_seq;
}

E
Eric Dumazet 已提交
599
static inline bool forced_push(const struct tcp_sock *tp)
L
Linus Torvalds 已提交
600 601 602 603
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

604
static void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
605
{
606
	struct tcp_sock *tp = tcp_sk(sk);
607 608 609 610
	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
611
	tcb->tcp_flags = TCPHDR_ACK;
612
	tcb->sacked  = 0;
613
	__skb_header_release(skb);
614
	tcp_add_write_queue_tail(sk, skb);
615 616
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
617
	if (tp->nonagle & TCP_NAGLE_PUSH)
618
		tp->nonagle &= ~TCP_NAGLE_PUSH;
619 620

	tcp_slow_start_after_idle_check(sk);
L
Linus Torvalds 已提交
621 622
}

623
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
624
{
I
Ilpo Järvinen 已提交
625
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
626 627 628
		tp->snd_up = tp->write_seq;
}

E
Eric Dumazet 已提交
629
/* If a not yet filled skb is pushed, do not send it if
630
 * we have data packets in Qdisc or NIC queues :
E
Eric Dumazet 已提交
631 632 633 634
 * 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
635 636 637
 * 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
638 639 640
 */
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
				int size_goal)
L
Linus Torvalds 已提交
641
{
E
Eric Dumazet 已提交
642 643
	return skb->len < size_goal &&
	       sysctl_tcp_autocorking &&
644
	       skb != tcp_write_queue_head(sk) &&
E
Eric Dumazet 已提交
645 646 647 648 649 650 651 652
	       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;
653

E
Eric Dumazet 已提交
654 655
	if (!tcp_send_head(sk))
		return;
656

E
Eric Dumazet 已提交
657 658 659 660 661 662 663 664 665 666 667 668 669
	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);
		}
670 671 672 673 674
		/* 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
675
	}
E
Eric Dumazet 已提交
676 677 678 679 680

	if (flags & MSG_MORE)
		nonagle = TCP_NAGLE_CORK;

	__tcp_push_pending_frames(sk, mss_now, nonagle);
L
Linus Torvalds 已提交
681 682
}

683 684
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
685 686
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
687
	int ret;
J
Jens Axboe 已提交
688

689 690 691
	ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
			      min(rd_desc->count, len), tss->flags,
			      skb_socket_splice);
692 693 694
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
695 696 697 698 699 700 701
}

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,
702
		.count	  = tss->len,
J
Jens Axboe 已提交
703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733
	};

	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;

734
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
735 736 737 738 739 740 741 742 743 744
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

745
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773
	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;
			}
774
			sk_wait_data(sk, &timeo, NULL);
J
Jens Axboe 已提交
775 776 777 778 779 780 781 782 783
			if (signal_pending(current)) {
				ret = sock_intr_errno(timeo);
				break;
			}
			continue;
		}
		tss.len -= ret;
		spliced += ret;

784 785
		if (!timeo)
			break;
J
Jens Axboe 已提交
786 787 788 789
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
790
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
791 792 793 794 795 796 797 798 799 800 801
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
802
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
803

804 805
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
				    bool force_schedule)
806 807 808 809 810 811
{
	struct sk_buff *skb;

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

812 813 814
	if (unlikely(tcp_under_memory_pressure(sk)))
		sk_mem_reclaim_partial(sk);

815
	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
816
	if (likely(skb)) {
817
		bool mem_scheduled;
818

819 820
		if (force_schedule) {
			mem_scheduled = true;
821 822
			sk_forced_mem_schedule(sk, skb->truesize);
		} else {
823
			mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
824
		}
825
		if (likely(mem_scheduled)) {
826
			skb_reserve(skb, sk->sk_prot->max_header);
827 828 829 830
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
E
Eric Dumazet 已提交
831
			skb->reserved_tailroom = skb->end - skb->tail - size;
832 833 834 835
			return skb;
		}
		__kfree_skb(skb);
	} else {
836
		sk->sk_prot->enter_memory_pressure(sk);
837 838 839 840 841
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
842 843 844 845
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
846
	u32 new_size_goal, size_goal;
E
Eric Dumazet 已提交
847 848 849 850

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

851 852
	/* 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
853 854 855 856 857 858 859 860 861
	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
862 863
	}

E
Eric Dumazet 已提交
864
	return max(size_goal, mss_now);
I
Ilpo Järvinen 已提交
865 866 867 868 869 870 871 872 873 874 875 876
}

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;
}

877 878
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
879 880
{
	struct tcp_sock *tp = tcp_sk(sk);
881
	int mss_now, size_goal;
L
Linus Torvalds 已提交
882 883 884 885
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

886 887 888 889 890 891
	/* 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)) {
892 893
		err = sk_stream_wait_connect(sk, &timeo);
		if (err != 0)
L
Linus Torvalds 已提交
894
			goto out_err;
895
	}
L
Linus Torvalds 已提交
896

897
	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
L
Linus Torvalds 已提交
898

I
Ilpo Järvinen 已提交
899
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
900 901 902 903
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
904
		goto out_err;
L
Linus Torvalds 已提交
905

906
	while (size > 0) {
907
		struct sk_buff *skb = tcp_write_queue_tail(sk);
908 909
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
910

911
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
912 913 914 915
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

916 917
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
L
Linus Torvalds 已提交
918 919 920
			if (!skb)
				goto wait_for_memory;

921
			skb_entail(sk, skb);
922
			copy = size_goal;
L
Linus Torvalds 已提交
923 924 925 926 927 928 929
		}

		if (copy > size)
			copy = size;

		i = skb_shinfo(skb)->nr_frags;
		can_coalesce = skb_can_coalesce(skb, i, page, offset);
H
Hans Westgaard Ry 已提交
930
		if (!can_coalesce && i >= sysctl_max_skb_frags) {
L
Linus Torvalds 已提交
931 932 933
			tcp_mark_push(tp, skb);
			goto new_segment;
		}
934
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
935
			goto wait_for_memory;
936

L
Linus Torvalds 已提交
937
		if (can_coalesce) {
E
Eric Dumazet 已提交
938
			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
939 940 941 942
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}
943
		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
944

L
Linus Torvalds 已提交
945 946 947 948
		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
949
		sk_mem_charge(sk, copy);
950
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
951 952
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
953
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
954 955

		if (!copied)
E
Eric Dumazet 已提交
956
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
957 958

		copied += copy;
959
		offset += copy;
960 961
		size -= copy;
		if (!size) {
962
			tcp_tx_timestamp(sk, skb);
L
Linus Torvalds 已提交
963
			goto out;
964
		}
L
Linus Torvalds 已提交
965

966
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
967 968 969 970
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
971
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
972
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
973 974 975 976 977 978
			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
979 980
		tcp_push(sk, flags & ~MSG_MORE, mss_now,
			 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
981

982 983
		err = sk_stream_wait_memory(sk, &timeo);
		if (err != 0)
L
Linus Torvalds 已提交
984 985
			goto do_error;

I
Ilpo Järvinen 已提交
986
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
987 988 989
	}

out:
990
	if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
E
Eric Dumazet 已提交
991
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
L
Linus Torvalds 已提交
992 993 994 995 996 997
	return copied;

do_error:
	if (copied)
		goto out;
out_err:
998 999 1000
	/* make sure we wake any epoll edge trigger waiter */
	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
		sk->sk_write_space(sk);
L
Linus Torvalds 已提交
1001 1002 1003
	return sk_stream_error(sk, flags, err);
}

1004 1005
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
1006 1007 1008 1009
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
1010
	    !sk_check_csum_caps(sk))
1011 1012
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
1013 1014

	lock_sock(sk);
1015
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
1016 1017 1018
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
1019
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
1020

1021
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
1022
{
1023
	const struct tcp_sock *tp = tcp_sk(sk);
1024
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
1025

K
Krishna Kumar 已提交
1026
	if (sg) {
1027 1028 1029 1030 1031 1032
		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 {
1033 1034 1035 1036 1037 1038 1039
			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
1040 1041 1042 1043

	return tmp;
}

1044 1045
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
1046
	if (tp->fastopen_req) {
1047 1048 1049 1050 1051
		kfree(tp->fastopen_req);
		tp->fastopen_req = NULL;
	}
}

1052 1053
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
				int *copied, size_t size)
1054 1055 1056 1057 1058 1059
{
	struct tcp_sock *tp = tcp_sk(sk);
	int err, flags;

	if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
		return -EOPNOTSUPP;
1060
	if (tp->fastopen_req)
1061 1062 1063 1064
		return -EALREADY; /* Another Fast Open is in progress */

	tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
				   sk->sk_allocation);
1065
	if (unlikely(!tp->fastopen_req))
1066 1067
		return -ENOBUFS;
	tp->fastopen_req->data = msg;
1068
	tp->fastopen_req->size = size;
1069 1070 1071 1072

	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
	err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
				    msg->msg_namelen, flags);
1073
	*copied = tp->fastopen_req->copied;
1074 1075 1076 1077
	tcp_free_fastopen_req(tp);
	return err;
}

1078
int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
L
Linus Torvalds 已提交
1079 1080 1081
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1082 1083
	int flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0;
1084
	bool sg;
L
Linus Torvalds 已提交
1085 1086 1087 1088 1089
	long timeo;

	lock_sock(sk);

	flags = msg->msg_flags;
1090
	if (flags & MSG_FASTOPEN) {
1091
		err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1092 1093 1094 1095 1096 1097
		if (err == -EINPROGRESS && copied_syn > 0)
			goto out;
		else if (err)
			goto out_err;
	}

L
Linus Torvalds 已提交
1098 1099
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

1100 1101 1102 1103 1104 1105
	/* 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)) {
1106 1107
		err = sk_stream_wait_connect(sk, &timeo);
		if (err != 0)
1108
			goto do_error;
1109
	}
L
Linus Torvalds 已提交
1110

P
Pavel Emelyanov 已提交
1111 1112 1113
	if (unlikely(tp->repair)) {
		if (tp->repair_queue == TCP_RECV_QUEUE) {
			copied = tcp_send_rcvq(sk, msg, size);
1114
			goto out_nopush;
P
Pavel Emelyanov 已提交
1115 1116 1117 1118 1119 1120 1121 1122 1123
		}

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

		/* 'common' sending to sendq */
	}

L
Linus Torvalds 已提交
1124
	/* This should be in poll */
1125
	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
L
Linus Torvalds 已提交
1126

I
Ilpo Järvinen 已提交
1127
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1128 1129 1130 1131 1132 1133

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

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1134
		goto out_err;
L
Linus Torvalds 已提交
1135

1136
	sg = !!(sk->sk_route_caps & NETIF_F_SG);
K
Krishna Kumar 已提交
1137

A
Al Viro 已提交
1138
	while (msg_data_left(msg)) {
1139 1140
		int copy = 0;
		int max = size_goal;
L
Linus Torvalds 已提交
1141

1142 1143 1144 1145 1146
		skb = tcp_write_queue_tail(sk);
		if (tcp_send_head(sk)) {
			if (skb->ip_summed == CHECKSUM_NONE)
				max = mss_now;
			copy = max - skb->len;
1147
		}
L
Linus Torvalds 已提交
1148

1149
		if (copy <= 0) {
L
Linus Torvalds 已提交
1150
new_segment:
1151 1152 1153 1154 1155
			/* 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
1156

1157 1158
			skb = sk_stream_alloc_skb(sk,
						  select_size(sk, sg),
1159 1160
						  sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
1161 1162
			if (!skb)
				goto wait_for_memory;
L
Linus Torvalds 已提交
1163

1164 1165 1166
			/*
			 * Check whether we can use HW checksum.
			 */
1167
			if (sk_check_csum_caps(sk))
1168
				skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
1169

1170 1171 1172
			skb_entail(sk, skb);
			copy = size_goal;
			max = size_goal;
1173

1174 1175 1176 1177 1178 1179 1180
			/* 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
1181

1182
		/* Try to append data to the end of skb. */
A
Al Viro 已提交
1183 1184
		if (copy > msg_data_left(msg))
			copy = msg_data_left(msg);
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199

		/* 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;
1200

1201 1202
			if (!skb_can_coalesce(skb, i, pfrag->page,
					      pfrag->offset)) {
H
Hans Westgaard Ry 已提交
1203
				if (i == sysctl_max_skb_frags || !sg) {
1204 1205
					tcp_mark_push(tp, skb);
					goto new_segment;
L
Linus Torvalds 已提交
1206
				}
1207
				merge = false;
L
Linus Torvalds 已提交
1208 1209
			}

1210 1211 1212 1213
			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
1214

1215 1216 1217 1218 1219 1220
			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
1221

1222 1223 1224 1225 1226 1227 1228
			/* 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);
1229
			}
1230 1231 1232 1233 1234 1235 1236 1237 1238
			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
1239

1240
		copied += copy;
A
Al Viro 已提交
1241
		if (!msg_data_left(msg)) {
1242 1243 1244
			tcp_tx_timestamp(sk, skb);
			goto out;
		}
L
Linus Torvalds 已提交
1245

1246
		if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1247 1248
			continue;

1249 1250 1251 1252 1253 1254 1255
		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
1256
wait_for_sndbuf:
1257
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
L
Linus Torvalds 已提交
1258
wait_for_memory:
1259 1260 1261
		if (copied)
			tcp_push(sk, flags & ~MSG_MORE, mss_now,
				 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
1262

1263 1264
		err = sk_stream_wait_memory(sk, &timeo);
		if (err != 0)
1265
			goto do_error;
L
Linus Torvalds 已提交
1266

1267
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1268 1269 1270
	}

out:
1271
	if (copied)
E
Eric Dumazet 已提交
1272
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1273
out_nopush:
L
Linus Torvalds 已提交
1274
	release_sock(sk);
1275
	return copied + copied_syn;
L
Linus Torvalds 已提交
1276 1277 1278

do_fault:
	if (!skb->len) {
1279 1280 1281 1282 1283
		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);
1284
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1285 1286 1287
	}

do_error:
1288
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1289 1290 1291
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
1292 1293 1294
	/* make sure we wake any epoll edge trigger waiter */
	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
		sk->sk_write_space(sk);
L
Linus Torvalds 已提交
1295 1296 1297
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1298
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1299 1300 1301 1302 1303 1304

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

1305
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328
{
	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
1329
				err = memcpy_to_msg(msg, &c, 1);
L
Linus Torvalds 已提交
1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348
			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
1349 1350 1351 1352 1353 1354 1355 1356
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) {
1357
		err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
P
Pavel Emelyanov 已提交
1358 1359 1360 1361 1362 1363 1364 1365 1366
		if (err)
			break;

		copied += skb->len;
	}

	return err ?: copied;
}

L
Linus Torvalds 已提交
1367 1368 1369 1370 1371 1372
/* 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.
 */
1373
static void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1374 1375
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1376
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1377 1378 1379

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

1380
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1381
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1382
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1383

1384 1385
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1386 1387
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1388
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1389
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1390
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1391 1392 1393 1394 1395 1396
		    /*
		     * 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.
		     */
1397 1398 1399 1400 1401
		    (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
1402
			time_to_ack = true;
L
Linus Torvalds 已提交
1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
	}

	/* 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
1424
				time_to_ack = true;
L
Linus Torvalds 已提交
1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
		}
	}
	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);

1436
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1437 1438 1439 1440 1441

	/* 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
1442
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1443 1444 1445 1446 1447 1448
	local_bh_enable();

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

1449
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
L
Linus Torvalds 已提交
1450 1451 1452 1453
{
	struct sk_buff *skb;
	u32 offset;

1454
	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
L
Linus Torvalds 已提交
1455
		offset = seq - TCP_SKB_CB(skb)->seq;
1456 1457
		if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
			pr_err_once("%s: found a SYN, please report !\n", __func__);
L
Linus Torvalds 已提交
1458
			offset--;
1459
		}
1460
		if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
L
Linus Torvalds 已提交
1461 1462 1463
			*off = offset;
			return skb;
		}
1464 1465 1466 1467
		/* 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
1468
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496
	}
	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) {
1497 1498
			int used;
			size_t len;
L
Linus Torvalds 已提交
1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509

			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);
1510
			if (used <= 0) {
1511 1512 1513 1514
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1515 1516 1517 1518
				seq += used;
				copied += used;
				offset += used;
			}
1519
			/* If recv_actor drops the lock (e.g. TCP splice
1520 1521 1522 1523
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1524 1525
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1526
				break;
1527 1528 1529 1530 1531
			/* 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
1532
		}
1533
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
D
Dan Williams 已提交
1534
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1535 1536 1537
			++seq;
			break;
		}
D
Dan Williams 已提交
1538
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1539 1540
		if (!desc->count)
			break;
1541
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1542 1543 1544 1545 1546 1547
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1548 1549
	if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
1550
		tcp_cleanup_rbuf(sk, copied);
1551
	}
L
Linus Torvalds 已提交
1552 1553
	return copied;
}
E
Eric Dumazet 已提交
1554
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1555 1556 1557 1558 1559 1560 1561 1562 1563

/*
 *	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.
 */

1564 1565
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
1566 1567 1568 1569 1570 1571 1572 1573 1574 1575
{
	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;
1576
	struct sk_buff *skb, *last;
I
Ilpo Järvinen 已提交
1577
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1578

1579
	if (unlikely(flags & MSG_ERRQUEUE))
1580
		return inet_recv_error(sk, msg, len, addr_len);
1581

1582 1583 1584
	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
	    (sk->sk_state == TCP_ESTABLISHED))
		sk_busy_loop(sk, nonblock);
1585

L
Linus Torvalds 已提交
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597
	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
1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612
	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
1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635
	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. */

1636
		last = skb_peek_tail(&sk->sk_receive_queue);
1637
		skb_queue_walk(&sk->sk_receive_queue, skb) {
1638
			last = skb;
L
Linus Torvalds 已提交
1639 1640 1641
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1642
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1643 1644 1645
				 "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
1646
				break;
1647

L
Linus Torvalds 已提交
1648
			offset = *seq - TCP_SKB_CB(skb)->seq;
1649 1650
			if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
				pr_err_once("%s: found a SYN, please report !\n", __func__);
L
Linus Torvalds 已提交
1651
				offset--;
1652
			}
L
Linus Torvalds 已提交
1653 1654
			if (offset < skb->len)
				goto found_ok_skb;
1655
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1656
				goto found_fin_ok;
J
Joe Perches 已提交
1657 1658 1659
			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);
1660
		}
L
Linus Torvalds 已提交
1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671

		/* 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 ||
1672
			    signal_pending(current))
L
Linus Torvalds 已提交
1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707
				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;
			}
		}

1708
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1709

1710
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1711 1712 1713 1714
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
1715
				tp->ucopy.msg = msg;
L
Linus Torvalds 已提交
1716 1717 1718 1719
			}

			tp->ucopy.len = len;

1720 1721
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748

			/* 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.
			 */
1749
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1750 1751 1752 1753 1754 1755 1756 1757 1758
				goto do_prequeue;

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

		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
1759 1760 1761
		} else {
			sk_wait_data(sk, &timeo, last);
		}
L
Linus Torvalds 已提交
1762 1763 1764 1765 1766 1767

		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

1768 1769
			chunk = len - tp->ucopy.len;
			if (chunk != 0) {
1770
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1771 1772 1773 1774 1775
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1776
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1777 1778 1779
do_prequeue:
				tcp_prequeue_process(sk);

1780 1781
				chunk = len - tp->ucopy.len;
				if (chunk != 0) {
1782
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1783 1784 1785 1786 1787
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1788 1789
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1790 1791 1792
			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
1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809
			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
1810
						urg_hole++;
L
Linus Torvalds 已提交
1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
1822
			err = skb_copy_datagram_msg(skb, offset, msg, used);
D
Dan Williams 已提交
1823 1824 1825 1826 1827
			if (err) {
				/* Exception. Bailout! */
				if (!copied)
					copied = -EFAULT;
				break;
L
Linus Torvalds 已提交
1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839
			}
		}

		*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;
1840
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1841 1842 1843 1844
		}
		if (used + offset < skb->len)
			continue;

1845
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1846
			goto found_fin_ok;
D
Dan Williams 已提交
1847 1848
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1849 1850 1851 1852 1853
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
D
Dan Williams 已提交
1854 1855
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1856 1857 1858 1859
		break;
	} while (len > 0);

	if (user_recv) {
1860
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1861 1862 1863 1864 1865 1866 1867
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1868
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882
				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. */
1883
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1884 1885 1886 1887 1888 1889 1890 1891 1892

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
1893
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1894
	goto out;
P
Pavel Emelyanov 已提交
1895 1896 1897 1898

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
1899
}
E
Eric Dumazet 已提交
1900
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
1901

I
Ilpo Järvinen 已提交
1902 1903 1904 1905 1906 1907 1908
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
1909
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1910 1911 1912 1913
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1914
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1915 1916 1917 1918

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1919
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1920 1921
		/* fall through */
	default:
1922
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1923
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1924 1925 1926 1927 1928
	}

	/* Change state AFTER socket is unhashed to avoid closed
	 * socket sitting in hash tables.
	 */
1929
	sk_state_store(sk, state);
I
Ilpo Järvinen 已提交
1930 1931

#ifdef STATE_TRACE
1932
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1933 1934 1935 1936
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1937 1938 1939 1940 1941 1942 1943
/*
 *	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.
 */

1944
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1945
  /* current state:        new state:      action:	*/
1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958
  [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
1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972
};

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
1973
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993
 */

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
1994
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
1995

A
Arun Sharma 已提交
1996 1997 1998 1999 2000 2001 2002
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);

2003 2004 2005 2006
	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
2007 2008 2009
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
2010 2011 2012 2013
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
2014
	int state;
L
Linus Torvalds 已提交
2015 2016 2017 2018 2019 2020 2021 2022

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

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

		/* Special case. */
2023
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2024 2025 2026 2027 2028 2029 2030 2031 2032

		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) {
2033 2034 2035 2036
		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
2037 2038 2039 2040
		data_was_unread += len;
		__kfree_skb(skb);
	}

2041
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2042

2043 2044 2045 2046
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2047 2048 2049 2050 2051 2052
	/* 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
2053
	 */
P
Pavel Emelyanov 已提交
2054 2055 2056
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2057
		/* Unread data was tossed, zap the connection. */
2058
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2059
		tcp_set_state(sk, TCP_CLOSE);
2060
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2061 2062 2063
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2064
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089
	} 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
2090 2091 2092 2093
		 * 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
2094 2095 2096 2097 2098 2099 2100
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2101 2102 2103 2104
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2105 2106 2107 2108 2109 2110 2111 2112 2113
	/* 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);
2114
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2115

H
Herbert Xu 已提交
2116 2117
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2118 2119 2120
	/* 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
2121 2122 2123 2124

	/*	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.
2125
	 *	We use a 1 minute timeout (about the same as BSD) then kill
L
Linus Torvalds 已提交
2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140
	 *	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);
2141 2142
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2143
		} else {
2144
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2145 2146

			if (tmo > TCP_TIMEWAIT_LEN) {
2147 2148
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2149 2150 2151 2152 2153 2154 2155
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2156
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2157
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2158 2159
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2160 2161
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2162 2163 2164
		}
	}

2165 2166 2167 2168 2169 2170
	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.
		 */
2171
		if (req)
2172
			reqsk_fastopen_remove(sk, req, false);
2173
		inet_csk_destroy_sock(sk);
2174
	}
L
Linus Torvalds 已提交
2175 2176 2177 2178 2179 2180 2181
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2182
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2183 2184 2185

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

E
Eric Dumazet 已提交
2186
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2187 2188 2189 2190 2191 2192 2193 2194 2195
{
	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);
2196
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2197 2198 2199 2200 2201 2202 2203 2204 2205
	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) {
2206
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2207 2208
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2209 2210 2211
	} 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
2212
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2213 2214 2215 2216 2217 2218 2219 2220 2221
		 * 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);
2222
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2223 2224
	__skb_queue_purge(&tp->out_of_order_queue);

E
Eric Dumazet 已提交
2225
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2226 2227 2228 2229 2230 2231

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

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
2232
	tp->srtt_us = 0;
2233 2234
	tp->write_seq += tp->max_window + 2;
	if (tp->write_seq == 0)
L
Linus Torvalds 已提交
2235
		tp->write_seq = 1;
2236
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2237
	tp->snd_cwnd = 2;
2238
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2239
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2240
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2241
	tp->snd_cwnd_cnt = 0;
2242
	tp->window_clamp = 0;
2243
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2244
	tcp_clear_retrans(tp);
2245
	inet_csk_delack_init(sk);
2246
	tcp_init_send_head(sk);
2247
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2248 2249
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2250
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2251 2252 2253 2254

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2255
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2256

E
Eric Dumazet 已提交
2257
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2258
{
2259
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2260 2261 2262
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2263 2264
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2265
{
2266
	struct tcp_repair_opt opt;
2267

2268 2269
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2270 2271 2272
			return -EFAULT;

		optbuf++;
2273
		len -= sizeof(opt);
2274

2275 2276 2277
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2278
			break;
2279
		case TCPOPT_WINDOW:
2280 2281 2282 2283 2284 2285
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2286

2287 2288 2289 2290
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2291 2292
			break;
		case TCPOPT_SACK_PERM:
2293 2294 2295
			if (opt.opt_val != 0)
				return -EINVAL;

2296 2297 2298 2299 2300
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2301 2302 2303
			if (opt.opt_val != 0)
				return -EINVAL;

2304 2305 2306 2307 2308 2309 2310 2311
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

L
Linus Torvalds 已提交
2312 2313 2314
/*
 *	Socket option code for TCP.
 */
2315
static int do_tcp_setsockopt(struct sock *sk, int level,
2316
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2317 2318
{
	struct tcp_sock *tp = tcp_sk(sk);
2319
	struct inet_connection_sock *icsk = inet_csk(sk);
2320
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
2321 2322 2323
	int val;
	int err = 0;

2324 2325 2326
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2327 2328 2329 2330 2331 2332
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2333
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2334 2335 2336 2337 2338
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2339
		err = tcp_set_congestion_control(sk, name);
2340 2341 2342
		release_sock(sk);
		return err;
	}
2343 2344 2345
	default:
		/* fallthru */
		break;
2346
	}
2347

L
Linus Torvalds 已提交
2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360
	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 */
2361
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378
			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;
2379
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2380 2381 2382 2383 2384
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2385 2386 2387 2388 2389 2390 2391
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2392 2393 2394
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
2395
		else {
A
Andreas Petlund 已提交
2396
			tp->thin_dupack = val;
Y
Yuchung Cheng 已提交
2397 2398
			if (tp->thin_dupack)
				tcp_disable_early_retrans(tp);
2399
		}
A
Andreas Petlund 已提交
2400 2401
		break;

P
Pavel Emelyanov 已提交
2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437
	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;

2438 2439 2440 2441
	case TCP_REPAIR_OPTIONS:
		if (!tp->repair)
			err = -EINVAL;
		else if (sk->sk_state == TCP_ESTABLISHED)
2442 2443 2444
			err = tcp_repair_options_est(tp,
					(struct tcp_repair_opt __user *)optval,
					optlen);
2445 2446 2447 2448
		else
			err = -EPERM;
		break;

L
Linus Torvalds 已提交
2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466
	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;
2467
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478
		}
		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))) {
2479
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2480 2481 2482 2483
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2484
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503
			}
		}
		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
2504
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2505 2506
		break;

2507 2508 2509 2510 2511 2512 2513
	case TCP_SAVE_SYN:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->save_syn = val;
		break;

L
Linus Torvalds 已提交
2514 2515 2516
	case TCP_LINGER2:
		if (val < 0)
			tp->linger2 = -1;
2517
		else if (val > net->ipv4.sysctl_tcp_fin_timeout / HZ)
L
Linus Torvalds 已提交
2518 2519 2520 2521 2522 2523
			tp->linger2 = 0;
		else
			tp->linger2 = val * HZ;
		break;

	case TCP_DEFER_ACCEPT:
2524 2525 2526 2527
		/* 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
2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543
		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) {
2544
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2545
		} else {
2546
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2547 2548
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2549 2550
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2551
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2552
				if (!(val & 1))
2553
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2554 2555 2556 2557
			}
		}
		break;

2558 2559 2560 2561 2562 2563
#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
2564
	case TCP_USER_TIMEOUT:
2565
		/* Cap the max time in ms TCP will retry or probe the window
2566 2567
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2568 2569 2570 2571
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2572
		break;
2573 2574 2575

	case TCP_FASTOPEN:
		if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2576 2577 2578
		    TCPF_LISTEN))) {
			tcp_fastopen_init_key_once(true);

2579
			fastopen_queue_tune(sk, val);
2580
		} else {
2581
			err = -EINVAL;
2582
		}
2583
		break;
2584 2585 2586 2587 2588 2589
	case TCP_TIMESTAMP:
		if (!tp->repair)
			err = -EPERM;
		else
			tp->tsoffset = val - tcp_time_stamp;
		break;
2590 2591 2592 2593
	case TCP_NOTSENT_LOWAT:
		tp->notsent_lowat = val;
		sk->sk_write_space(sk);
		break;
L
Linus Torvalds 已提交
2594 2595 2596
	default:
		err = -ENOPROTOOPT;
		break;
2597 2598
	}

L
Linus Torvalds 已提交
2599 2600 2601 2602
	release_sock(sk);
	return err;
}

2603
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2604
		   unsigned int optlen)
2605
{
2606
	const struct inet_connection_sock *icsk = inet_csk(sk);
2607 2608 2609 2610 2611 2612

	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
2613
EXPORT_SYMBOL(tcp_setsockopt);
2614 2615

#ifdef CONFIG_COMPAT
2616
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2617
			  char __user *optval, unsigned int optlen)
2618
{
2619 2620 2621
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2622 2623
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2624
EXPORT_SYMBOL(compat_tcp_setsockopt);
2625 2626
#endif

L
Linus Torvalds 已提交
2627
/* Return information about state of tcp endpoint in API format. */
2628
void tcp_get_info(struct sock *sk, struct tcp_info *info)
L
Linus Torvalds 已提交
2629
{
2630
	const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
2631
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2632
	u32 now = tcp_time_stamp;
2633
	unsigned int start;
2634
	int notsent_bytes;
2635
	u64 rate64;
2636
	u32 rate;
L
Linus Torvalds 已提交
2637 2638

	memset(info, 0, sizeof(*info));
2639 2640
	if (sk->sk_type != SOCK_STREAM)
		return;
L
Linus Torvalds 已提交
2641

2642 2643
	info->tcpi_state = sk_state_load(sk);

2644
	info->tcpi_ca_state = icsk->icsk_ca_state;
2645
	info->tcpi_retransmits = icsk->icsk_retransmits;
2646
	info->tcpi_probes = icsk->icsk_probes_out;
2647
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2648 2649 2650

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2651
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2652 2653 2654 2655 2656
		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;
2657
	}
L
Linus Torvalds 已提交
2658

E
Eric Dumazet 已提交
2659
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2660
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2661 2662
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2663 2664
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2665

2666 2667
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2668
	info->tcpi_snd_mss = tp->mss_cache;
2669
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2670

2671
	if (info->tcpi_state == TCP_LISTEN) {
2672 2673 2674 2675 2676 2677
		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
2678 2679 2680 2681 2682
	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);
2683
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2684 2685
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2686
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2687
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2688 2689
	info->tcpi_rtt = tp->srtt_us >> 3;
	info->tcpi_rttvar = tp->mdev_us >> 2;
L
Linus Torvalds 已提交
2690 2691 2692 2693 2694 2695 2696 2697 2698
	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;
2699

2700
	rate = READ_ONCE(sk->sk_pacing_rate);
2701 2702
	rate64 = rate != ~0U ? rate : ~0ULL;
	put_unaligned(rate64, &info->tcpi_pacing_rate);
2703 2704

	rate = READ_ONCE(sk->sk_max_pacing_rate);
2705 2706
	rate64 = rate != ~0U ? rate : ~0ULL;
	put_unaligned(rate64, &info->tcpi_max_pacing_rate);
2707

2708 2709
	do {
		start = u64_stats_fetch_begin_irq(&tp->syncp);
2710 2711
		put_unaligned(tp->bytes_acked, &info->tcpi_bytes_acked);
		put_unaligned(tp->bytes_received, &info->tcpi_bytes_received);
2712
	} while (u64_stats_fetch_retry_irq(&tp->syncp, start));
2713 2714
	info->tcpi_segs_out = tp->segs_out;
	info->tcpi_segs_in = tp->segs_in;
2715 2716 2717 2718 2719

	notsent_bytes = READ_ONCE(tp->write_seq) - READ_ONCE(tp->snd_nxt);
	info->tcpi_notsent_bytes = max(0, notsent_bytes);

	info->tcpi_min_rtt = tcp_min_rtt(tp);
2720 2721
	info->tcpi_data_segs_in = tp->data_segs_in;
	info->tcpi_data_segs_out = tp->data_segs_out;
L
Linus Torvalds 已提交
2722 2723 2724
}
EXPORT_SYMBOL_GPL(tcp_get_info);

2725 2726
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2727
{
2728
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2729
	struct tcp_sock *tp = tcp_sk(sk);
2730
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742
	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:
2743
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2744 2745
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2746 2747
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2748 2749 2750 2751 2752 2753 2754 2755
		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
2756
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2757 2758
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2759
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2760 2761
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2762
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2763 2764
		break;
	case TCP_SYNCNT:
2765
		val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2766 2767 2768 2769
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
2770
			val = (val ? : net->ipv4.sysctl_tcp_fin_timeout) / HZ;
L
Linus Torvalds 已提交
2771 2772
		break;
	case TCP_DEFER_ACCEPT:
2773 2774
		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
2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793
		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;
	}
2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813
	case TCP_CC_INFO: {
		const struct tcp_congestion_ops *ca_ops;
		union tcp_cc_info info;
		size_t sz = 0;
		int attr;

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

		ca_ops = icsk->icsk_ca_ops;
		if (ca_ops && ca_ops->get_info)
			sz = ca_ops->get_info(sk, ~0U, &attr, &info);

		len = min_t(unsigned int, len, sz);
		if (put_user(len, optlen))
			return -EFAULT;
		if (copy_to_user(optval, &info, len))
			return -EFAULT;
		return 0;
	}
L
Linus Torvalds 已提交
2814
	case TCP_QUICKACK:
2815
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2816
		break;
2817 2818 2819 2820 2821 2822 2823

	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;
2824
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2825 2826
			return -EFAULT;
		return 0;
2827

2828 2829 2830 2831 2832 2833
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2834

P
Pavel Emelyanov 已提交
2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854
	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;

2855 2856 2857
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
2858 2859

	case TCP_FASTOPEN:
2860
		val = icsk->icsk_accept_queue.fastopenq.max_qlen;
2861 2862
		break;

2863 2864 2865
	case TCP_TIMESTAMP:
		val = tcp_time_stamp + tp->tsoffset;
		break;
2866 2867 2868
	case TCP_NOTSENT_LOWAT:
		val = tp->notsent_lowat;
		break;
2869 2870 2871 2872 2873 2874 2875 2876 2877
	case TCP_SAVE_SYN:
		val = tp->save_syn;
		break;
	case TCP_SAVED_SYN: {
		if (get_user(len, optlen))
			return -EFAULT;

		lock_sock(sk);
		if (tp->saved_syn) {
2878 2879 2880 2881 2882 2883 2884 2885 2886
			if (len < tp->saved_syn[0]) {
				if (put_user(tp->saved_syn[0], optlen)) {
					release_sock(sk);
					return -EFAULT;
				}
				release_sock(sk);
				return -EINVAL;
			}
			len = tp->saved_syn[0];
2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904
			if (put_user(len, optlen)) {
				release_sock(sk);
				return -EFAULT;
			}
			if (copy_to_user(optval, tp->saved_syn + 1, len)) {
				release_sock(sk);
				return -EFAULT;
			}
			tcp_saved_syn_free(tp);
			release_sock(sk);
		} else {
			release_sock(sk);
			len = 0;
			if (put_user(len, optlen))
				return -EFAULT;
		}
		return 0;
	}
L
Linus Torvalds 已提交
2905 2906
	default:
		return -ENOPROTOOPT;
2907
	}
L
Linus Torvalds 已提交
2908 2909 2910 2911 2912 2913 2914 2915

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

2916 2917 2918 2919 2920 2921 2922 2923 2924 2925
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
2926
EXPORT_SYMBOL(tcp_getsockopt);
2927 2928

#ifdef CONFIG_COMPAT
2929 2930
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2931
{
2932 2933 2934
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2935 2936
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2937
EXPORT_SYMBOL(compat_tcp_getsockopt);
2938
#endif
L
Linus Torvalds 已提交
2939

2940
#ifdef CONFIG_TCP_MD5SIG
E
Eric Dumazet 已提交
2941
static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2942
static DEFINE_MUTEX(tcp_md5sig_mutex);
E
Eric Dumazet 已提交
2943
static bool tcp_md5sig_pool_populated = false;
2944

2945
static void __tcp_alloc_md5sig_pool(void)
2946
{
H
Herbert Xu 已提交
2947
	struct crypto_ahash *hash;
2948 2949
	int cpu;

H
Herbert Xu 已提交
2950
	hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
2951
	if (IS_ERR(hash))
H
Herbert Xu 已提交
2952 2953
		return;

2954
	for_each_possible_cpu(cpu) {
H
Herbert Xu 已提交
2955
		struct ahash_request *req;
2956

H
Herbert Xu 已提交
2957 2958 2959 2960 2961 2962 2963 2964 2965 2966
		if (per_cpu(tcp_md5sig_pool, cpu).md5_req)
			continue;

		req = ahash_request_alloc(hash, GFP_KERNEL);
		if (!req)
			return;

		ahash_request_set_callback(req, 0, NULL, NULL);

		per_cpu(tcp_md5sig_pool, cpu).md5_req = req;
2967
	}
E
Eric Dumazet 已提交
2968 2969
	/* before setting tcp_md5sig_pool_populated, we must commit all writes
	 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2970 2971
	 */
	smp_wmb();
E
Eric Dumazet 已提交
2972
	tcp_md5sig_pool_populated = true;
2973 2974
}

2975
bool tcp_alloc_md5sig_pool(void)
2976
{
E
Eric Dumazet 已提交
2977
	if (unlikely(!tcp_md5sig_pool_populated)) {
2978 2979
		mutex_lock(&tcp_md5sig_mutex);

E
Eric Dumazet 已提交
2980
		if (!tcp_md5sig_pool_populated)
2981 2982 2983
			__tcp_alloc_md5sig_pool();

		mutex_unlock(&tcp_md5sig_mutex);
2984
	}
E
Eric Dumazet 已提交
2985
	return tcp_md5sig_pool_populated;
2986 2987 2988
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
2989 2990 2991 2992 2993 2994 2995 2996 2997

/**
 *	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)
2998
{
E
Eric Dumazet 已提交
2999
	local_bh_disable();
3000

E
Eric Dumazet 已提交
3001 3002 3003 3004 3005
	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
3006 3007 3008 3009
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
3010

3011
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3012
			const struct tcphdr *th)
3013 3014
{
	struct scatterlist sg;
3015
	struct tcphdr hdr;
3016

3017 3018 3019 3020
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

3021
	/* options aren't included in the hash */
3022
	sg_init_one(&sg, &hdr, sizeof(hdr));
H
Herbert Xu 已提交
3023 3024
	ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(hdr));
	return crypto_ahash_update(hp->md5_req);
3025 3026 3027 3028
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3029
			  const struct sk_buff *skb, unsigned int header_len)
3030 3031 3032
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
H
Herbert Xu 已提交
3033
	struct ahash_request *req = hp->md5_req;
3034 3035 3036
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
3037
	const struct skb_shared_info *shi = skb_shinfo(skb);
3038
	struct sk_buff *frag_iter;
3039 3040 3041 3042

	sg_init_table(&sg, 1);

	sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
H
Herbert Xu 已提交
3043 3044
	ahash_request_set_crypt(req, &sg, NULL, head_data_len);
	if (crypto_ahash_update(req))
3045 3046 3047 3048
		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
3049 3050 3051 3052 3053
		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));
H
Herbert Xu 已提交
3054 3055
		ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f));
		if (crypto_ahash_update(req))
3056 3057 3058
			return 1;
	}

3059 3060 3061 3062
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3063 3064 3065 3066
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

3067
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3068 3069 3070 3071
{
	struct scatterlist sg;

	sg_init_one(&sg, key->key, key->keylen);
H
Herbert Xu 已提交
3072 3073
	ahash_request_set_crypt(hp->md5_req, &sg, NULL, key->keylen);
	return crypto_ahash_update(hp->md5_req);
3074 3075 3076
}
EXPORT_SYMBOL(tcp_md5_hash_key);

3077 3078
#endif

A
Andi Kleen 已提交
3079 3080
void tcp_done(struct sock *sk)
{
3081 3082
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

3083
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3084
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3085 3086 3087

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
3088
	if (req)
3089
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
3090 3091 3092 3093 3094 3095 3096 3097 3098 3099

	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);

3100 3101 3102
int tcp_abort(struct sock *sk, int err)
{
	if (!sk_fullsock(sk)) {
3103 3104 3105 3106 3107 3108 3109 3110 3111
		if (sk->sk_state == TCP_NEW_SYN_RECV) {
			struct request_sock *req = inet_reqsk(sk);

			local_bh_disable();
			inet_csk_reqsk_queue_drop_and_put(req->rsk_listener,
							  req);
			local_bh_enable();
			return 0;
		}
3112 3113 3114 3115 3116 3117 3118
		sock_gen_put(sk);
		return -EOPNOTSUPP;
	}

	/* Don't race with userspace socket closes such as tcp_close. */
	lock_sock(sk);

3119 3120 3121 3122 3123
	if (sk->sk_state == TCP_LISTEN) {
		tcp_set_state(sk, TCP_CLOSE);
		inet_csk_listen_stop(sk);
	}

3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145
	/* Don't race with BH socket closes such as inet_csk_listen_stop. */
	local_bh_disable();
	bh_lock_sock(sk);

	if (!sock_flag(sk, SOCK_DEAD)) {
		sk->sk_err = err;
		/* This barrier is coupled with smp_rmb() in tcp_poll() */
		smp_wmb();
		sk->sk_error_report(sk);
		if (tcp_need_reset(sk->sk_state))
			tcp_send_active_reset(sk, GFP_ATOMIC);
		tcp_done(sk);
	}

	bh_unlock_sock(sk);
	local_bh_enable();
	release_sock(sk);
	sock_put(sk);
	return 0;
}
EXPORT_SYMBOL_GPL(tcp_abort);

3146
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3147 3148 3149 3150

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
3151 3152
	ssize_t ret;

L
Linus Torvalds 已提交
3153 3154
	if (!str)
		return 0;
3155 3156 3157 3158 3159

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

L
Linus Torvalds 已提交
3160 3161 3162 3163
	return 1;
}
__setup("thash_entries=", set_thash_entries);

F
Fabian Frederick 已提交
3164
static void __init tcp_init_mem(void)
3165
{
E
Eric Dumazet 已提交
3166 3167
	unsigned long limit = nr_free_buffer_pages() / 16;

3168
	limit = max(limit, 128UL);
E
Eric Dumazet 已提交
3169 3170 3171
	sysctl_tcp_mem[0] = limit / 4 * 3;		/* 4.68 % */
	sysctl_tcp_mem[1] = limit;			/* 6.25 % */
	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;	/* 9.37 % */
3172 3173
}

L
Linus Torvalds 已提交
3174 3175
void __init tcp_init(void)
{
3176
	unsigned long limit;
3177
	int max_rshare, max_wshare, cnt;
3178
	unsigned int i;
L
Linus Torvalds 已提交
3179

3180
	sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
L
Linus Torvalds 已提交
3181

3182 3183
	percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
	percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3184 3185 3186
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3187
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3188 3189 3190 3191 3192 3193

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3194
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3195
		alloc_large_system_hash("TCP established",
3196
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3197
					thash_entries,
E
Eric Dumazet 已提交
3198
					17, /* one slot per 128 KB of memory */
3199
					0,
L
Linus Torvalds 已提交
3200
					NULL,
3201
					&tcp_hashinfo.ehash_mask,
3202
					0,
3203
					thash_entries ? 0 : 512 * 1024);
E
Eric Dumazet 已提交
3204
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3205
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
E
Eric Dumazet 已提交
3206

3207 3208
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3209
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3210
		alloc_large_system_hash("TCP bind",
3211
					sizeof(struct inet_bind_hashbucket),
3212
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3213
					17, /* one slot per 128 KB of memory */
3214
					0,
3215
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3216
					NULL,
3217
					0,
L
Linus Torvalds 已提交
3218
					64 * 1024);
3219
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3220 3221 3222
	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
3223 3224
	}

E
Eric Dumazet 已提交
3225 3226 3227 3228 3229 3230

	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
3231

3232
	tcp_init_mem();
3233
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3234
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3235 3236
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3237

3238
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3239
	sysctl_tcp_wmem[1] = 16*1024;
3240
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3241

3242
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3243
	sysctl_tcp_rmem[1] = 87380;
3244
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3245

3246
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3247
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3248

3249
	tcp_metrics_init();
3250
	BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
E
Eric Dumazet 已提交
3251
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3252
}