tcp.c 84.0 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, u16 tsflags, struct sk_buff *skb)
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{
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	if (tsflags) {
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		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, tsflags, &shinfo->tx_flags);
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		if (tsflags & SOF_TIMESTAMPING_TX_ACK)
			tcb->txstamp_ack = 1;
		if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
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			shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
	}
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}

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/*
 *	Wait for a TCP event.
 *
 *	Note that we don't need to lock the socket, as the upper poll layers
 *	take care of normal races (between the test and the event) and we don't
 *	go look at any of the socket buffers directly.
 */
unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
	unsigned int mask;
	struct sock *sk = sock->sk;
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	const struct tcp_sock *tp = tcp_sk(sk);
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	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,
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				 * IO signal will be lost. Memory barrier
				 * pairs with the input side.
L
Linus Torvalds 已提交
530
				 */
531
				smp_mb__after_atomic();
532
				if (sk_stream_is_writeable(sk))
L
Linus Torvalds 已提交
533 534
					mask |= POLLOUT | POLLWRNORM;
			}
535 536
		} else
			mask |= POLLOUT | POLLWRNORM;
L
Linus Torvalds 已提交
537 538 539 540

		if (tp->urg_data & TCP_URG_VALID)
			mask |= POLLPRI;
	}
T
Tom Marshall 已提交
541 542
	/* This barrier is coupled with smp_wmb() in tcp_reset() */
	smp_rmb();
543
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
T
Tom Marshall 已提交
544 545
		mask |= POLLERR;

L
Linus Torvalds 已提交
546 547
	return mask;
}
E
Eric Dumazet 已提交
548
EXPORT_SYMBOL(tcp_poll);
L
Linus Torvalds 已提交
549 550 551 552 553

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
554
	bool slow;
L
Linus Torvalds 已提交
555 556 557 558 559 560

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

E
Eric Dumazet 已提交
561
		slow = lock_sock_fast(sk);
562
		answ = tcp_inq(sk);
E
Eric Dumazet 已提交
563
		unlock_sock_fast(sk, slow);
L
Linus Torvalds 已提交
564 565 566 567 568 569 570 571 572 573 574 575 576
		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;
577 578 579 580 581 582 583 584 585
	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
586 587
	default:
		return -ENOIOCTLCMD;
588
	}
L
Linus Torvalds 已提交
589 590 591

	return put_user(answ, (int __user *)arg);
}
E
Eric Dumazet 已提交
592
EXPORT_SYMBOL(tcp_ioctl);
L
Linus Torvalds 已提交
593 594 595

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
596
	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
L
Linus Torvalds 已提交
597 598 599
	tp->pushed_seq = tp->write_seq;
}

E
Eric Dumazet 已提交
600
static inline bool forced_push(const struct tcp_sock *tp)
L
Linus Torvalds 已提交
601 602 603 604
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

605
static void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
606
{
607
	struct tcp_sock *tp = tcp_sk(sk);
608 609 610 611
	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
612
	tcb->tcp_flags = TCPHDR_ACK;
613
	tcb->sacked  = 0;
614
	__skb_header_release(skb);
615
	tcp_add_write_queue_tail(sk, skb);
616 617
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
618
	if (tp->nonagle & TCP_NAGLE_PUSH)
619
		tp->nonagle &= ~TCP_NAGLE_PUSH;
620 621

	tcp_slow_start_after_idle_check(sk);
L
Linus Torvalds 已提交
622 623
}

624
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
625
{
I
Ilpo Järvinen 已提交
626
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
627 628 629
		tp->snd_up = tp->write_seq;
}

E
Eric Dumazet 已提交
630
/* If a not yet filled skb is pushed, do not send it if
631
 * we have data packets in Qdisc or NIC queues :
E
Eric Dumazet 已提交
632 633 634 635
 * 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
636 637 638
 * 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
639 640 641
 */
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
				int size_goal)
L
Linus Torvalds 已提交
642
{
E
Eric Dumazet 已提交
643 644
	return skb->len < size_goal &&
	       sysctl_tcp_autocorking &&
645
	       skb != tcp_write_queue_head(sk) &&
E
Eric Dumazet 已提交
646 647 648 649 650 651 652 653
	       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;
654

E
Eric Dumazet 已提交
655 656
	if (!tcp_send_head(sk))
		return;
657

E
Eric Dumazet 已提交
658 659 660 661 662 663 664 665 666 667 668 669 670
	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);
		}
671 672 673 674 675
		/* 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
676
	}
E
Eric Dumazet 已提交
677 678 679 680 681

	if (flags & MSG_MORE)
		nonagle = TCP_NAGLE_CORK;

	__tcp_push_pending_frames(sk, mss_now, nonagle);
L
Linus Torvalds 已提交
682 683
}

684 685
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
686 687
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
688
	int ret;
J
Jens Axboe 已提交
689

690 691 692
	ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
			      min(rd_desc->count, len), tss->flags,
			      skb_socket_splice);
693 694 695
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
696 697 698 699 700 701 702
}

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,
703
		.count	  = tss->len,
J
Jens Axboe 已提交
704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734
	};

	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;

735
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
736 737 738 739 740 741 742 743 744 745
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

746
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774
	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;
			}
775
			sk_wait_data(sk, &timeo, NULL);
J
Jens Axboe 已提交
776 777 778 779 780 781 782 783 784
			if (signal_pending(current)) {
				ret = sock_intr_errno(timeo);
				break;
			}
			continue;
		}
		tss.len -= ret;
		spliced += ret;

785 786
		if (!timeo)
			break;
J
Jens Axboe 已提交
787 788 789 790
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
791
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
792 793 794 795 796 797 798 799 800 801 802
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
803
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
804

805 806
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
				    bool force_schedule)
807 808 809 810 811 812
{
	struct sk_buff *skb;

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

813 814 815
	if (unlikely(tcp_under_memory_pressure(sk)))
		sk_mem_reclaim_partial(sk);

816
	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
817
	if (likely(skb)) {
818
		bool mem_scheduled;
819

820 821
		if (force_schedule) {
			mem_scheduled = true;
822 823
			sk_forced_mem_schedule(sk, skb->truesize);
		} else {
824
			mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
825
		}
826
		if (likely(mem_scheduled)) {
827
			skb_reserve(skb, sk->sk_prot->max_header);
828 829 830 831
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
E
Eric Dumazet 已提交
832
			skb->reserved_tailroom = skb->end - skb->tail - size;
833 834 835 836
			return skb;
		}
		__kfree_skb(skb);
	} else {
837
		sk->sk_prot->enter_memory_pressure(sk);
838 839 840 841 842
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
843 844 845 846
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
847
	u32 new_size_goal, size_goal;
E
Eric Dumazet 已提交
848 849 850 851

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

852 853
	/* 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
854 855 856 857 858 859 860 861 862
	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
863 864
	}

E
Eric Dumazet 已提交
865
	return max(size_goal, mss_now);
I
Ilpo Järvinen 已提交
866 867 868 869 870 871 872 873 874 875 876 877
}

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;
}

878 879
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
880 881
{
	struct tcp_sock *tp = tcp_sk(sk);
882
	int mss_now, size_goal;
L
Linus Torvalds 已提交
883 884 885 886
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

887 888 889 890 891 892
	/* 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)) {
893 894
		err = sk_stream_wait_connect(sk, &timeo);
		if (err != 0)
L
Linus Torvalds 已提交
895
			goto out_err;
896
	}
L
Linus Torvalds 已提交
897

898
	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
L
Linus Torvalds 已提交
899

I
Ilpo Järvinen 已提交
900
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
901 902 903 904
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
905
		goto out_err;
L
Linus Torvalds 已提交
906

907
	while (size > 0) {
908
		struct sk_buff *skb = tcp_write_queue_tail(sk);
909 910
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
911

912 913
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0 ||
		    !tcp_skb_can_collapse_to(skb)) {
L
Linus Torvalds 已提交
914 915 916 917
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

918 919
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
L
Linus Torvalds 已提交
920 921 922
			if (!skb)
				goto wait_for_memory;

923
			skb_entail(sk, skb);
924
			copy = size_goal;
L
Linus Torvalds 已提交
925 926 927 928 929 930 931
		}

		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
932
		if (!can_coalesce && i >= sysctl_max_skb_frags) {
L
Linus Torvalds 已提交
933 934 935
			tcp_mark_push(tp, skb);
			goto new_segment;
		}
936
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
937
			goto wait_for_memory;
938

L
Linus Torvalds 已提交
939
		if (can_coalesce) {
E
Eric Dumazet 已提交
940
			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
941 942 943 944
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}
945
		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
946

L
Linus Torvalds 已提交
947 948 949 950
		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
951
		sk_mem_charge(sk, copy);
952
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
953 954
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
955
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
956 957

		if (!copied)
E
Eric Dumazet 已提交
958
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
959 960

		copied += copy;
961
		offset += copy;
962 963
		size -= copy;
		if (!size) {
964
			tcp_tx_timestamp(sk, sk->sk_tsflags, skb);
L
Linus Torvalds 已提交
965
			goto out;
966
		}
L
Linus Torvalds 已提交
967

968
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
969 970 971 972
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
973
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
974
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
975 976 977 978 979 980
			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
981 982
		tcp_push(sk, flags & ~MSG_MORE, mss_now,
			 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
983

984 985
		err = sk_stream_wait_memory(sk, &timeo);
		if (err != 0)
L
Linus Torvalds 已提交
986 987
			goto do_error;

I
Ilpo Järvinen 已提交
988
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
989 990 991
	}

out:
992
	if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
E
Eric Dumazet 已提交
993
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
L
Linus Torvalds 已提交
994 995 996 997 998 999
	return copied;

do_error:
	if (copied)
		goto out;
out_err:
1000 1001 1002
	/* 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
1003 1004 1005
	return sk_stream_error(sk, flags, err);
}

1006 1007
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
1008 1009 1010 1011
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
1012
	    !sk_check_csum_caps(sk))
1013 1014
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
1015 1016

	lock_sock(sk);
1017
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
1018 1019 1020
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
1021
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
1022

1023
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
1024
{
1025
	const struct tcp_sock *tp = tcp_sk(sk);
1026
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
1027

K
Krishna Kumar 已提交
1028
	if (sg) {
1029 1030 1031 1032 1033 1034
		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 {
1035 1036 1037 1038 1039 1040 1041
			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
1042 1043 1044 1045

	return tmp;
}

1046 1047
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
1048
	if (tp->fastopen_req) {
1049 1050 1051 1052 1053
		kfree(tp->fastopen_req);
		tp->fastopen_req = NULL;
	}
}

1054 1055
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
				int *copied, size_t size)
1056 1057 1058 1059 1060 1061
{
	struct tcp_sock *tp = tcp_sk(sk);
	int err, flags;

	if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
		return -EOPNOTSUPP;
1062
	if (tp->fastopen_req)
1063 1064 1065 1066
		return -EALREADY; /* Another Fast Open is in progress */

	tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
				   sk->sk_allocation);
1067
	if (unlikely(!tp->fastopen_req))
1068 1069
		return -ENOBUFS;
	tp->fastopen_req->data = msg;
1070
	tp->fastopen_req->size = size;
1071 1072 1073 1074

	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
	err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
				    msg->msg_namelen, flags);
1075
	*copied = tp->fastopen_req->copied;
1076 1077 1078 1079
	tcp_free_fastopen_req(tp);
	return err;
}

1080
int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
L
Linus Torvalds 已提交
1081 1082 1083
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1084
	struct sockcm_cookie sockc;
1085 1086
	int flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0;
1087
	bool sg;
L
Linus Torvalds 已提交
1088 1089 1090 1091 1092
	long timeo;

	lock_sock(sk);

	flags = msg->msg_flags;
1093
	if (flags & MSG_FASTOPEN) {
1094
		err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1095 1096 1097 1098 1099 1100
		if (err == -EINPROGRESS && copied_syn > 0)
			goto out;
		else if (err)
			goto out_err;
	}

L
Linus Torvalds 已提交
1101 1102
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

1103 1104 1105 1106 1107 1108
	/* 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)) {
1109 1110
		err = sk_stream_wait_connect(sk, &timeo);
		if (err != 0)
1111
			goto do_error;
1112
	}
L
Linus Torvalds 已提交
1113

P
Pavel Emelyanov 已提交
1114 1115 1116
	if (unlikely(tp->repair)) {
		if (tp->repair_queue == TCP_RECV_QUEUE) {
			copied = tcp_send_rcvq(sk, msg, size);
1117
			goto out_nopush;
P
Pavel Emelyanov 已提交
1118 1119 1120 1121 1122 1123 1124 1125 1126
		}

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

		/* 'common' sending to sendq */
	}

1127 1128 1129 1130 1131 1132 1133 1134 1135
	sockc.tsflags = sk->sk_tsflags;
	if (msg->msg_controllen) {
		err = sock_cmsg_send(sk, msg, &sockc);
		if (unlikely(err)) {
			err = -EINVAL;
			goto out_err;
		}
	}

L
Linus Torvalds 已提交
1136
	/* This should be in poll */
1137
	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
L
Linus Torvalds 已提交
1138

I
Ilpo Järvinen 已提交
1139
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1140 1141 1142 1143 1144 1145

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

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1146
		goto out_err;
L
Linus Torvalds 已提交
1147

1148
	sg = !!(sk->sk_route_caps & NETIF_F_SG);
K
Krishna Kumar 已提交
1149

A
Al Viro 已提交
1150
	while (msg_data_left(msg)) {
1151 1152
		int copy = 0;
		int max = size_goal;
L
Linus Torvalds 已提交
1153

1154 1155 1156 1157 1158
		skb = tcp_write_queue_tail(sk);
		if (tcp_send_head(sk)) {
			if (skb->ip_summed == CHECKSUM_NONE)
				max = mss_now;
			copy = max - skb->len;
1159
		}
L
Linus Torvalds 已提交
1160

1161
		if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
L
Linus Torvalds 已提交
1162
new_segment:
1163 1164 1165 1166 1167
			/* 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
1168

1169 1170
			skb = sk_stream_alloc_skb(sk,
						  select_size(sk, sg),
1171 1172
						  sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
1173 1174
			if (!skb)
				goto wait_for_memory;
L
Linus Torvalds 已提交
1175

1176 1177 1178
			/*
			 * Check whether we can use HW checksum.
			 */
1179
			if (sk_check_csum_caps(sk))
1180
				skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
1181

1182 1183 1184
			skb_entail(sk, skb);
			copy = size_goal;
			max = size_goal;
1185

1186 1187 1188 1189 1190 1191 1192
			/* 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
1193

1194
		/* Try to append data to the end of skb. */
A
Al Viro 已提交
1195 1196
		if (copy > msg_data_left(msg))
			copy = msg_data_left(msg);
1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211

		/* 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;
1212

1213 1214
			if (!skb_can_coalesce(skb, i, pfrag->page,
					      pfrag->offset)) {
H
Hans Westgaard Ry 已提交
1215
				if (i == sysctl_max_skb_frags || !sg) {
1216 1217
					tcp_mark_push(tp, skb);
					goto new_segment;
L
Linus Torvalds 已提交
1218
				}
1219
				merge = false;
L
Linus Torvalds 已提交
1220 1221
			}

1222 1223 1224 1225
			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
1226

1227 1228 1229 1230 1231 1232
			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
1233

1234 1235 1236 1237 1238 1239 1240
			/* 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);
1241
			}
1242 1243 1244 1245 1246 1247 1248 1249 1250
			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
1251

1252
		copied += copy;
A
Al Viro 已提交
1253
		if (!msg_data_left(msg)) {
1254
			tcp_tx_timestamp(sk, sockc.tsflags, skb);
1255 1256
			if (unlikely(flags & MSG_EOR))
				TCP_SKB_CB(skb)->eor = 1;
1257 1258
			goto out;
		}
L
Linus Torvalds 已提交
1259

1260
		if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1261 1262
			continue;

1263 1264 1265 1266 1267 1268 1269
		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
1270
wait_for_sndbuf:
1271
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
L
Linus Torvalds 已提交
1272
wait_for_memory:
1273 1274 1275
		if (copied)
			tcp_push(sk, flags & ~MSG_MORE, mss_now,
				 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
1276

1277 1278
		err = sk_stream_wait_memory(sk, &timeo);
		if (err != 0)
1279
			goto do_error;
L
Linus Torvalds 已提交
1280

1281
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1282 1283 1284
	}

out:
1285
	if (copied)
E
Eric Dumazet 已提交
1286
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1287
out_nopush:
L
Linus Torvalds 已提交
1288
	release_sock(sk);
1289
	return copied + copied_syn;
L
Linus Torvalds 已提交
1290 1291 1292

do_fault:
	if (!skb->len) {
1293 1294 1295 1296 1297
		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);
1298
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1299 1300 1301
	}

do_error:
1302
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1303 1304 1305
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
1306 1307 1308
	/* 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
1309 1310 1311
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1312
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1313 1314 1315 1316 1317 1318

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

1319
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342
{
	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
1343
				err = memcpy_to_msg(msg, &c, 1);
L
Linus Torvalds 已提交
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
			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
1363 1364 1365 1366 1367 1368 1369 1370
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) {
1371
		err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
P
Pavel Emelyanov 已提交
1372 1373 1374 1375 1376 1377 1378 1379 1380
		if (err)
			break;

		copied += skb->len;
	}

	return err ?: copied;
}

L
Linus Torvalds 已提交
1381 1382 1383 1384 1385 1386
/* 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.
 */
1387
static void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1388 1389
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1390
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1391 1392 1393

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

1394
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1395
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1396
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1397

1398 1399
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1400 1401
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1402
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1403
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1404
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1405 1406 1407 1408 1409 1410
		    /*
		     * 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.
		     */
1411 1412 1413 1414 1415
		    (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
1416
			time_to_ack = true;
L
Linus Torvalds 已提交
1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437
	}

	/* 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
1438
				time_to_ack = true;
L
Linus Torvalds 已提交
1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449
		}
	}
	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);

1450
	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1451 1452

	while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
P
Peter Zijlstra 已提交
1453
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1454 1455 1456 1457 1458

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

1459
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
L
Linus Torvalds 已提交
1460 1461 1462 1463
{
	struct sk_buff *skb;
	u32 offset;

1464
	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
L
Linus Torvalds 已提交
1465
		offset = seq - TCP_SKB_CB(skb)->seq;
1466 1467
		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
1468
			offset--;
1469
		}
1470
		if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
L
Linus Torvalds 已提交
1471 1472 1473
			*off = offset;
			return skb;
		}
1474 1475 1476 1477
		/* 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
1478
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506
	}
	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) {
1507 1508
			int used;
			size_t len;
L
Linus Torvalds 已提交
1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519

			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);
1520
			if (used <= 0) {
1521 1522 1523 1524
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1525 1526 1527 1528
				seq += used;
				copied += used;
				offset += used;
			}
1529
			/* If recv_actor drops the lock (e.g. TCP splice
1530 1531 1532 1533
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1534 1535
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1536
				break;
1537 1538 1539 1540 1541
			/* 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
1542
		}
1543
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
D
Dan Williams 已提交
1544
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1545 1546 1547
			++seq;
			break;
		}
D
Dan Williams 已提交
1548
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1549 1550
		if (!desc->count)
			break;
1551
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1552 1553 1554 1555 1556 1557
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1558 1559
	if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
1560
		tcp_cleanup_rbuf(sk, copied);
1561
	}
L
Linus Torvalds 已提交
1562 1563
	return copied;
}
E
Eric Dumazet 已提交
1564
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1565 1566 1567 1568 1569 1570 1571 1572 1573

/*
 *	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.
 */

1574 1575
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
1576 1577 1578 1579 1580 1581 1582 1583 1584 1585
{
	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;
1586
	struct sk_buff *skb, *last;
I
Ilpo Järvinen 已提交
1587
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1588

1589
	if (unlikely(flags & MSG_ERRQUEUE))
1590
		return inet_recv_error(sk, msg, len, addr_len);
1591

1592 1593 1594
	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
	    (sk->sk_state == TCP_ESTABLISHED))
		sk_busy_loop(sk, nonblock);
1595

L
Linus Torvalds 已提交
1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607
	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
1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622
	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
1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645
	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. */

1646
		last = skb_peek_tail(&sk->sk_receive_queue);
1647
		skb_queue_walk(&sk->sk_receive_queue, skb) {
1648
			last = skb;
L
Linus Torvalds 已提交
1649 1650 1651
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1652
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1653 1654 1655
				 "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
1656
				break;
1657

L
Linus Torvalds 已提交
1658
			offset = *seq - TCP_SKB_CB(skb)->seq;
1659 1660
			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
1661
				offset--;
1662
			}
L
Linus Torvalds 已提交
1663 1664
			if (offset < skb->len)
				goto found_ok_skb;
1665
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1666
				goto found_fin_ok;
J
Joe Perches 已提交
1667 1668 1669
			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);
1670
		}
L
Linus Torvalds 已提交
1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681

		/* 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 ||
1682
			    signal_pending(current))
L
Linus Torvalds 已提交
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 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717
				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;
			}
		}

1718
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1719

1720
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1721 1722 1723 1724
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
1725
				tp->ucopy.msg = msg;
L
Linus Torvalds 已提交
1726 1727 1728 1729
			}

			tp->ucopy.len = len;

1730 1731
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758

			/* 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.
			 */
1759
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1760 1761 1762 1763 1764 1765 1766 1767 1768
				goto do_prequeue;

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

		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
1769 1770 1771
		} else {
			sk_wait_data(sk, &timeo, last);
		}
L
Linus Torvalds 已提交
1772 1773 1774 1775 1776 1777

		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

1778 1779
			chunk = len - tp->ucopy.len;
			if (chunk != 0) {
1780
				NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1781 1782 1783 1784 1785
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1786
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1787 1788 1789
do_prequeue:
				tcp_prequeue_process(sk);

1790 1791
				chunk = len - tp->ucopy.len;
				if (chunk != 0) {
1792
					NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1793 1794 1795 1796 1797
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1798 1799
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1800 1801 1802
			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
1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819
			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
1820
						urg_hole++;
L
Linus Torvalds 已提交
1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
1832
			err = skb_copy_datagram_msg(skb, offset, msg, used);
D
Dan Williams 已提交
1833 1834 1835 1836 1837
			if (err) {
				/* Exception. Bailout! */
				if (!copied)
					copied = -EFAULT;
				break;
L
Linus Torvalds 已提交
1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
			}
		}

		*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;
1850
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1851 1852 1853 1854
		}
		if (used + offset < skb->len)
			continue;

1855
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1856
			goto found_fin_ok;
D
Dan Williams 已提交
1857 1858
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1859 1860 1861 1862 1863
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
D
Dan Williams 已提交
1864 1865
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1866 1867 1868 1869
		break;
	} while (len > 0);

	if (user_recv) {
1870
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1871 1872 1873 1874 1875 1876 1877
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1878
				NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892
				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. */
1893
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1894 1895 1896 1897 1898 1899 1900 1901 1902

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
1903
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1904
	goto out;
P
Pavel Emelyanov 已提交
1905 1906 1907 1908

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
1909
}
E
Eric Dumazet 已提交
1910
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
1911

I
Ilpo Järvinen 已提交
1912 1913 1914 1915 1916 1917 1918
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
1919
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1920 1921 1922 1923
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1924
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1925 1926 1927 1928

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1929
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1930 1931
		/* fall through */
	default:
1932
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1933
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1934 1935 1936 1937 1938
	}

	/* Change state AFTER socket is unhashed to avoid closed
	 * socket sitting in hash tables.
	 */
1939
	sk_state_store(sk, state);
I
Ilpo Järvinen 已提交
1940 1941

#ifdef STATE_TRACE
1942
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1943 1944 1945 1946
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1947 1948 1949 1950 1951 1952 1953
/*
 *	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.
 */

1954
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1955
  /* current state:        new state:      action:	*/
1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968
  [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
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982
};

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
1983
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
 */

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
2004
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
2005

A
Arun Sharma 已提交
2006 2007 2008 2009 2010 2011 2012
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);

2013 2014 2015 2016
	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
2017 2018 2019
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
2020 2021 2022 2023
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
2024
	int state;
L
Linus Torvalds 已提交
2025 2026 2027 2028 2029 2030 2031 2032

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

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

		/* Special case. */
2033
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2034 2035 2036 2037 2038 2039 2040 2041 2042

		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) {
2043 2044 2045 2046
		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
2047 2048 2049 2050
		data_was_unread += len;
		__kfree_skb(skb);
	}

2051
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2052

2053 2054 2055 2056
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2057 2058 2059 2060 2061 2062
	/* 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
2063
	 */
P
Pavel Emelyanov 已提交
2064 2065 2066
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2067
		/* Unread data was tossed, zap the connection. */
2068
		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2069
		tcp_set_state(sk, TCP_CLOSE);
2070
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2071 2072 2073
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2074
		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099
	} 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
2100 2101 2102 2103
		 * 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
2104 2105 2106 2107 2108 2109 2110
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2111 2112 2113 2114
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2115 2116 2117 2118 2119 2120 2121 2122 2123
	/* 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);
2124
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2125

H
Herbert Xu 已提交
2126 2127
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2128 2129 2130
	/* 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
2131 2132 2133 2134

	/*	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.
2135
	 *	We use a 1 minute timeout (about the same as BSD) then kill
L
Linus Torvalds 已提交
2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150
	 *	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);
2151
			__NET_INC_STATS(sock_net(sk),
2152
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2153
		} else {
2154
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2155 2156

			if (tmo > TCP_TIMEWAIT_LEN) {
2157 2158
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2159 2160 2161 2162 2163 2164 2165
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2166
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2167
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2168 2169
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2170
			__NET_INC_STATS(sock_net(sk),
2171
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2172 2173 2174
		}
	}

2175 2176 2177 2178 2179 2180
	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.
		 */
2181
		if (req)
2182
			reqsk_fastopen_remove(sk, req, false);
2183
		inet_csk_destroy_sock(sk);
2184
	}
L
Linus Torvalds 已提交
2185 2186 2187 2188 2189 2190 2191
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2192
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2193 2194 2195

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

E
Eric Dumazet 已提交
2196
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2197 2198 2199 2200 2201 2202 2203 2204 2205
{
	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);
2206
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2207 2208 2209 2210 2211 2212 2213 2214 2215
	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) {
2216
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2217 2218
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2219 2220 2221
	} 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
2222
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2223 2224 2225 2226 2227 2228 2229 2230 2231
		 * 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);
2232
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2233 2234
	__skb_queue_purge(&tp->out_of_order_queue);

E
Eric Dumazet 已提交
2235
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2236 2237 2238 2239 2240 2241

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

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
2242
	tp->srtt_us = 0;
2243 2244
	tp->write_seq += tp->max_window + 2;
	if (tp->write_seq == 0)
L
Linus Torvalds 已提交
2245
		tp->write_seq = 1;
2246
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2247
	tp->snd_cwnd = 2;
2248
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2249
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2250
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2251
	tp->snd_cwnd_cnt = 0;
2252
	tp->window_clamp = 0;
2253
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2254
	tcp_clear_retrans(tp);
2255
	inet_csk_delack_init(sk);
2256
	tcp_init_send_head(sk);
2257
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2258 2259
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2260
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2261 2262 2263 2264

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2265
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2266

E
Eric Dumazet 已提交
2267
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2268
{
2269
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2270 2271 2272
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2273 2274
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2275
{
2276
	struct tcp_repair_opt opt;
2277

2278 2279
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2280 2281 2282
			return -EFAULT;

		optbuf++;
2283
		len -= sizeof(opt);
2284

2285 2286 2287
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2288
			break;
2289
		case TCPOPT_WINDOW:
2290 2291 2292 2293 2294 2295
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2296

2297 2298 2299 2300
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2301 2302
			break;
		case TCPOPT_SACK_PERM:
2303 2304 2305
			if (opt.opt_val != 0)
				return -EINVAL;

2306 2307 2308 2309 2310
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2311 2312 2313
			if (opt.opt_val != 0)
				return -EINVAL;

2314 2315 2316 2317 2318 2319 2320 2321
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

L
Linus Torvalds 已提交
2322 2323 2324
/*
 *	Socket option code for TCP.
 */
2325
static int do_tcp_setsockopt(struct sock *sk, int level,
2326
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2327 2328
{
	struct tcp_sock *tp = tcp_sk(sk);
2329
	struct inet_connection_sock *icsk = inet_csk(sk);
2330
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
2331 2332 2333
	int val;
	int err = 0;

2334 2335 2336
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2337 2338 2339 2340 2341 2342
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2343
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2344 2345 2346 2347 2348
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2349
		err = tcp_set_congestion_control(sk, name);
2350 2351 2352
		release_sock(sk);
		return err;
	}
2353 2354 2355
	default:
		/* fallthru */
		break;
2356
	}
2357

L
Linus Torvalds 已提交
2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370
	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 */
2371
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388
			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;
2389
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2390 2391 2392 2393 2394
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2395 2396 2397 2398 2399 2400 2401
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2402 2403 2404
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
2405
		else {
A
Andreas Petlund 已提交
2406
			tp->thin_dupack = val;
Y
Yuchung Cheng 已提交
2407 2408
			if (tp->thin_dupack)
				tcp_disable_early_retrans(tp);
2409
		}
A
Andreas Petlund 已提交
2410 2411
		break;

P
Pavel Emelyanov 已提交
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 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447
	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;

2448 2449 2450 2451
	case TCP_REPAIR_OPTIONS:
		if (!tp->repair)
			err = -EINVAL;
		else if (sk->sk_state == TCP_ESTABLISHED)
2452 2453 2454
			err = tcp_repair_options_est(tp,
					(struct tcp_repair_opt __user *)optval,
					optlen);
2455 2456 2457 2458
		else
			err = -EPERM;
		break;

L
Linus Torvalds 已提交
2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476
	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;
2477
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488
		}
		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))) {
2489
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2490 2491 2492 2493
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2494
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513
			}
		}
		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
2514
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2515 2516
		break;

2517 2518 2519 2520 2521 2522 2523
	case TCP_SAVE_SYN:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->save_syn = val;
		break;

L
Linus Torvalds 已提交
2524 2525 2526
	case TCP_LINGER2:
		if (val < 0)
			tp->linger2 = -1;
2527
		else if (val > net->ipv4.sysctl_tcp_fin_timeout / HZ)
L
Linus Torvalds 已提交
2528 2529 2530 2531 2532 2533
			tp->linger2 = 0;
		else
			tp->linger2 = val * HZ;
		break;

	case TCP_DEFER_ACCEPT:
2534 2535 2536 2537
		/* 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
2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553
		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) {
2554
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2555
		} else {
2556
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2557 2558
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2559 2560
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2561
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2562
				if (!(val & 1))
2563
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2564 2565 2566 2567
			}
		}
		break;

2568 2569 2570 2571 2572 2573
#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
2574
	case TCP_USER_TIMEOUT:
2575
		/* Cap the max time in ms TCP will retry or probe the window
2576 2577
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2578 2579 2580 2581
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2582
		break;
2583 2584 2585

	case TCP_FASTOPEN:
		if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2586 2587 2588
		    TCPF_LISTEN))) {
			tcp_fastopen_init_key_once(true);

2589
			fastopen_queue_tune(sk, val);
2590
		} else {
2591
			err = -EINVAL;
2592
		}
2593
		break;
2594 2595 2596 2597 2598 2599
	case TCP_TIMESTAMP:
		if (!tp->repair)
			err = -EPERM;
		else
			tp->tsoffset = val - tcp_time_stamp;
		break;
2600 2601 2602 2603
	case TCP_NOTSENT_LOWAT:
		tp->notsent_lowat = val;
		sk->sk_write_space(sk);
		break;
L
Linus Torvalds 已提交
2604 2605 2606
	default:
		err = -ENOPROTOOPT;
		break;
2607 2608
	}

L
Linus Torvalds 已提交
2609 2610 2611 2612
	release_sock(sk);
	return err;
}

2613
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2614
		   unsigned int optlen)
2615
{
2616
	const struct inet_connection_sock *icsk = inet_csk(sk);
2617 2618 2619 2620 2621 2622

	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
2623
EXPORT_SYMBOL(tcp_setsockopt);
2624 2625

#ifdef CONFIG_COMPAT
2626
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2627
			  char __user *optval, unsigned int optlen)
2628
{
2629 2630 2631
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2632 2633
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2634
EXPORT_SYMBOL(compat_tcp_setsockopt);
2635 2636
#endif

L
Linus Torvalds 已提交
2637
/* Return information about state of tcp endpoint in API format. */
2638
void tcp_get_info(struct sock *sk, struct tcp_info *info)
L
Linus Torvalds 已提交
2639
{
2640
	const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
2641
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2642
	u32 now = tcp_time_stamp;
2643
	unsigned int start;
2644
	int notsent_bytes;
2645
	u64 rate64;
2646
	u32 rate;
L
Linus Torvalds 已提交
2647 2648

	memset(info, 0, sizeof(*info));
2649 2650
	if (sk->sk_type != SOCK_STREAM)
		return;
L
Linus Torvalds 已提交
2651

2652 2653
	info->tcpi_state = sk_state_load(sk);

2654
	info->tcpi_ca_state = icsk->icsk_ca_state;
2655
	info->tcpi_retransmits = icsk->icsk_retransmits;
2656
	info->tcpi_probes = icsk->icsk_probes_out;
2657
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2658 2659 2660

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2661
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2662 2663 2664 2665 2666
		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;
2667
	}
L
Linus Torvalds 已提交
2668

E
Eric Dumazet 已提交
2669
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2670
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2671 2672
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2673 2674
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2675

2676 2677
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2678
	info->tcpi_snd_mss = tp->mss_cache;
2679
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2680

2681
	if (info->tcpi_state == TCP_LISTEN) {
2682 2683 2684 2685 2686 2687
		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
2688 2689 2690 2691 2692
	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);
2693
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2694 2695
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2696
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2697
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2698 2699
	info->tcpi_rtt = tp->srtt_us >> 3;
	info->tcpi_rttvar = tp->mdev_us >> 2;
L
Linus Torvalds 已提交
2700 2701 2702 2703 2704 2705 2706 2707 2708
	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;
2709

2710
	rate = READ_ONCE(sk->sk_pacing_rate);
2711 2712
	rate64 = rate != ~0U ? rate : ~0ULL;
	put_unaligned(rate64, &info->tcpi_pacing_rate);
2713 2714

	rate = READ_ONCE(sk->sk_max_pacing_rate);
2715 2716
	rate64 = rate != ~0U ? rate : ~0ULL;
	put_unaligned(rate64, &info->tcpi_max_pacing_rate);
2717

2718 2719
	do {
		start = u64_stats_fetch_begin_irq(&tp->syncp);
2720 2721
		put_unaligned(tp->bytes_acked, &info->tcpi_bytes_acked);
		put_unaligned(tp->bytes_received, &info->tcpi_bytes_received);
2722
	} while (u64_stats_fetch_retry_irq(&tp->syncp, start));
2723 2724
	info->tcpi_segs_out = tp->segs_out;
	info->tcpi_segs_in = tp->segs_in;
2725 2726 2727 2728 2729

	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);
2730 2731
	info->tcpi_data_segs_in = tp->data_segs_in;
	info->tcpi_data_segs_out = tp->data_segs_out;
L
Linus Torvalds 已提交
2732 2733 2734
}
EXPORT_SYMBOL_GPL(tcp_get_info);

2735 2736
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2737
{
2738
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2739
	struct tcp_sock *tp = tcp_sk(sk);
2740
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752
	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:
2753
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2754 2755
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2756 2757
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2758 2759 2760 2761 2762 2763 2764 2765
		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
2766
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2767 2768
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2769
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2770 2771
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2772
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2773 2774
		break;
	case TCP_SYNCNT:
2775
		val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2776 2777 2778 2779
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
2780
			val = (val ? : net->ipv4.sysctl_tcp_fin_timeout) / HZ;
L
Linus Torvalds 已提交
2781 2782
		break;
	case TCP_DEFER_ACCEPT:
2783 2784
		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
2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803
		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;
	}
2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823
	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
2824
	case TCP_QUICKACK:
2825
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2826
		break;
2827 2828 2829 2830 2831 2832 2833

	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;
2834
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2835 2836
			return -EFAULT;
		return 0;
2837

2838 2839 2840 2841 2842 2843
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2844

P
Pavel Emelyanov 已提交
2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864
	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;

2865 2866 2867
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
2868 2869

	case TCP_FASTOPEN:
2870
		val = icsk->icsk_accept_queue.fastopenq.max_qlen;
2871 2872
		break;

2873 2874 2875
	case TCP_TIMESTAMP:
		val = tcp_time_stamp + tp->tsoffset;
		break;
2876 2877 2878
	case TCP_NOTSENT_LOWAT:
		val = tp->notsent_lowat;
		break;
2879 2880 2881 2882 2883 2884 2885 2886 2887
	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) {
2888 2889 2890 2891 2892 2893 2894 2895 2896
			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];
2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914
			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
2915 2916
	default:
		return -ENOPROTOOPT;
2917
	}
L
Linus Torvalds 已提交
2918 2919 2920 2921 2922 2923 2924 2925

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

2926 2927 2928 2929 2930 2931 2932 2933 2934 2935
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
2936
EXPORT_SYMBOL(tcp_getsockopt);
2937 2938

#ifdef CONFIG_COMPAT
2939 2940
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2941
{
2942 2943 2944
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2945 2946
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2947
EXPORT_SYMBOL(compat_tcp_getsockopt);
2948
#endif
L
Linus Torvalds 已提交
2949

2950
#ifdef CONFIG_TCP_MD5SIG
E
Eric Dumazet 已提交
2951
static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2952
static DEFINE_MUTEX(tcp_md5sig_mutex);
E
Eric Dumazet 已提交
2953
static bool tcp_md5sig_pool_populated = false;
2954

2955
static void __tcp_alloc_md5sig_pool(void)
2956
{
H
Herbert Xu 已提交
2957
	struct crypto_ahash *hash;
2958 2959
	int cpu;

H
Herbert Xu 已提交
2960
	hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
2961
	if (IS_ERR(hash))
H
Herbert Xu 已提交
2962 2963
		return;

2964
	for_each_possible_cpu(cpu) {
H
Herbert Xu 已提交
2965
		struct ahash_request *req;
2966

H
Herbert Xu 已提交
2967 2968 2969 2970 2971 2972 2973 2974 2975 2976
		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;
2977
	}
E
Eric Dumazet 已提交
2978 2979
	/* before setting tcp_md5sig_pool_populated, we must commit all writes
	 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2980 2981
	 */
	smp_wmb();
E
Eric Dumazet 已提交
2982
	tcp_md5sig_pool_populated = true;
2983 2984
}

2985
bool tcp_alloc_md5sig_pool(void)
2986
{
E
Eric Dumazet 已提交
2987
	if (unlikely(!tcp_md5sig_pool_populated)) {
2988 2989
		mutex_lock(&tcp_md5sig_mutex);

E
Eric Dumazet 已提交
2990
		if (!tcp_md5sig_pool_populated)
2991 2992 2993
			__tcp_alloc_md5sig_pool();

		mutex_unlock(&tcp_md5sig_mutex);
2994
	}
E
Eric Dumazet 已提交
2995
	return tcp_md5sig_pool_populated;
2996 2997 2998
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
2999 3000 3001 3002 3003 3004 3005 3006 3007

/**
 *	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)
3008
{
E
Eric Dumazet 已提交
3009
	local_bh_disable();
3010

E
Eric Dumazet 已提交
3011 3012 3013 3014 3015
	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
3016 3017 3018 3019
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
3020

3021
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3022
			const struct tcphdr *th)
3023 3024
{
	struct scatterlist sg;
3025
	struct tcphdr hdr;
3026

3027 3028 3029 3030
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

3031
	/* options aren't included in the hash */
3032
	sg_init_one(&sg, &hdr, sizeof(hdr));
H
Herbert Xu 已提交
3033 3034
	ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(hdr));
	return crypto_ahash_update(hp->md5_req);
3035 3036 3037 3038
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3039
			  const struct sk_buff *skb, unsigned int header_len)
3040 3041 3042
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
H
Herbert Xu 已提交
3043
	struct ahash_request *req = hp->md5_req;
3044 3045 3046
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
3047
	const struct skb_shared_info *shi = skb_shinfo(skb);
3048
	struct sk_buff *frag_iter;
3049 3050 3051 3052

	sg_init_table(&sg, 1);

	sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
H
Herbert Xu 已提交
3053 3054
	ahash_request_set_crypt(req, &sg, NULL, head_data_len);
	if (crypto_ahash_update(req))
3055 3056 3057 3058
		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
3059 3060 3061 3062 3063
		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
3064 3065
		ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f));
		if (crypto_ahash_update(req))
3066 3067 3068
			return 1;
	}

3069 3070 3071 3072
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3073 3074 3075 3076
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

3077
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3078 3079 3080 3081
{
	struct scatterlist sg;

	sg_init_one(&sg, key->key, key->keylen);
H
Herbert Xu 已提交
3082 3083
	ahash_request_set_crypt(hp->md5_req, &sg, NULL, key->keylen);
	return crypto_ahash_update(hp->md5_req);
3084 3085 3086
}
EXPORT_SYMBOL(tcp_md5_hash_key);

3087 3088
#endif

A
Andi Kleen 已提交
3089 3090
void tcp_done(struct sock *sk)
{
3091 3092
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

3093
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3094
		TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3095 3096 3097

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
3098
	if (req)
3099
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
3100 3101 3102 3103 3104 3105 3106 3107 3108 3109

	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);

3110 3111 3112
int tcp_abort(struct sock *sk, int err)
{
	if (!sk_fullsock(sk)) {
3113 3114 3115 3116 3117 3118 3119 3120 3121
		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;
		}
3122 3123 3124 3125 3126 3127 3128
		sock_gen_put(sk);
		return -EOPNOTSUPP;
	}

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

3129 3130 3131 3132 3133
	if (sk->sk_state == TCP_LISTEN) {
		tcp_set_state(sk, TCP_CLOSE);
		inet_csk_listen_stop(sk);
	}

3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155
	/* 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);

3156
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3157 3158 3159 3160

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
3161 3162
	ssize_t ret;

L
Linus Torvalds 已提交
3163 3164
	if (!str)
		return 0;
3165 3166 3167 3168 3169

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

L
Linus Torvalds 已提交
3170 3171 3172 3173
	return 1;
}
__setup("thash_entries=", set_thash_entries);

F
Fabian Frederick 已提交
3174
static void __init tcp_init_mem(void)
3175
{
E
Eric Dumazet 已提交
3176 3177
	unsigned long limit = nr_free_buffer_pages() / 16;

3178
	limit = max(limit, 128UL);
E
Eric Dumazet 已提交
3179 3180 3181
	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 % */
3182 3183
}

L
Linus Torvalds 已提交
3184 3185
void __init tcp_init(void)
{
3186
	unsigned long limit;
3187
	int max_rshare, max_wshare, cnt;
3188
	unsigned int i;
L
Linus Torvalds 已提交
3189

3190
	sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
L
Linus Torvalds 已提交
3191

3192 3193
	percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
	percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3194 3195 3196
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3197
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3198 3199 3200 3201 3202 3203

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3204
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3205
		alloc_large_system_hash("TCP established",
3206
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3207
					thash_entries,
E
Eric Dumazet 已提交
3208
					17, /* one slot per 128 KB of memory */
3209
					0,
L
Linus Torvalds 已提交
3210
					NULL,
3211
					&tcp_hashinfo.ehash_mask,
3212
					0,
3213
					thash_entries ? 0 : 512 * 1024);
E
Eric Dumazet 已提交
3214
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3215
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
E
Eric Dumazet 已提交
3216

3217 3218
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3219
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3220
		alloc_large_system_hash("TCP bind",
3221
					sizeof(struct inet_bind_hashbucket),
3222
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3223
					17, /* one slot per 128 KB of memory */
3224
					0,
3225
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3226
					NULL,
3227
					0,
L
Linus Torvalds 已提交
3228
					64 * 1024);
3229
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3230 3231 3232
	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
3233 3234
	}

E
Eric Dumazet 已提交
3235 3236 3237 3238 3239 3240

	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
3241

3242
	tcp_init_mem();
3243
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3244
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3245 3246
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3247

3248
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3249
	sysctl_tcp_wmem[1] = 16*1024;
3250
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3251

3252
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3253
	sysctl_tcp_rmem[1] = 87380;
3254
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3255

3256
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3257
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3258

3259
	tcp_metrics_init();
3260
	BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
E
Eric Dumazet 已提交
3261
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3262
}