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 <linux/kernel.h>
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#include <linux/module.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
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#include <linux/skbuff.h>
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#include <linux/scatterlist.h>
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#include <linux/splice.h>
#include <linux/net.h>
#include <linux/socket.h>
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#include <linux/random.h>
#include <linux/bootmem.h>
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#include <linux/highmem.h>
#include <linux/swap.h>
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#include <linux/cache.h>
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#include <linux/err.h>
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#include <linux/crypto.h>
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#include <linux/time.h>
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#include <linux/slab.h>
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#include <net/icmp.h>
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#include <net/inet_common.h>
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#include <net/tcp.h>
#include <net/xfrm.h>
#include <net/ip.h>
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#include <net/netdma.h>
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#include <net/sock.h>
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#include <asm/uaccess.h>
#include <asm/ioctls.h>
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#include <net/busy_poll.h>
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int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
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int sysctl_tcp_min_tso_segs __read_mostly = 2;

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int sysctl_tcp_autocorking __read_mostly = 1;

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struct percpu_counter tcp_orphan_count;
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EXPORT_SYMBOL_GPL(tcp_orphan_count);

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

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atomic_long_t tcp_memory_allocated;	/* Current allocated memory. */
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EXPORT_SYMBOL(tcp_memory_allocated);
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/*
 * Current number of TCP sockets.
 */
struct percpu_counter tcp_sockets_allocated;
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EXPORT_SYMBOL(tcp_sockets_allocated);

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

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

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

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

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

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

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

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

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

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

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

	tp->reordering = sysctl_tcp_reordering;
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	tcp_enable_early_retrans(tp);
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	icsk->icsk_ca_ops = &tcp_init_congestion_ops;

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	tp->tsoffset = 0;

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	sk->sk_state = TCP_CLOSE;

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

	icsk->icsk_sync_mss = tcp_sync_mss;

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

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

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

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/*
 *	Wait for a TCP event.
 *
 *	Note that we don't need to lock the socket, as the upper poll layers
 *	take care of normal races (between the test and the event) and we don't
 *	go look at any of the socket buffers directly.
 */
unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
	unsigned int mask;
	struct sock *sk = sock->sk;
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	const struct tcp_sock *tp = tcp_sk(sk);
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	sock_rps_record_flow(sk);

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

	mask = 0;

	/*
	 * POLLHUP is certainly not done right. But poll() doesn't
	 * have a notion of HUP in just one direction, and for a
	 * socket the read side is more interesting.
	 *
	 * Some poll() documentation says that POLLHUP is incompatible
	 * with the POLLOUT/POLLWR flags, so somebody should check this
	 * all. But careful, it tends to be safer to return too many
	 * bits than too few, and you can easily break real applications
	 * if you don't tell them that something has hung up!
	 *
	 * Check-me.
	 *
	 * Check number 1. POLLHUP is _UNMASKABLE_ event (see UNIX98 and
	 * our fs/select.c). It means that after we received EOF,
	 * poll always returns immediately, making impossible poll() on write()
	 * in state CLOSE_WAIT. One solution is evident --- to set POLLHUP
	 * if and only if shutdown has been made in both directions.
	 * Actually, it is interesting to look how Solaris and DUX
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	 * solve this dilemma. I would prefer, if POLLHUP were maskable,
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	 * then we could set it on SND_SHUTDOWN. BTW examples given
	 * in Stevens' books assume exactly this behaviour, it explains
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	 * why POLLHUP is incompatible with POLLOUT.	--ANK
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	 *
	 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
	 * blocking on fresh not-connected or disconnected socket. --ANK
	 */
	if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE)
		mask |= POLLHUP;
	if (sk->sk_shutdown & RCV_SHUTDOWN)
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		mask |= POLLIN | POLLRDNORM | POLLRDHUP;
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	/* Connected or passive Fast Open socket? */
	if (sk->sk_state != TCP_SYN_SENT &&
	    (sk->sk_state != TCP_SYN_RECV || tp->fastopen_rsk != NULL)) {
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		int target = sock_rcvlowat(sk, 0, INT_MAX);

		if (tp->urg_seq == tp->copied_seq &&
		    !sock_flag(sk, SOCK_URGINLINE) &&
		    tp->urg_data)
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			target++;
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		/* Potential race condition. If read of tp below will
		 * escape above sk->sk_state, we can be illegally awaken
		 * in SYN_* states. */
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		if (tp->rcv_nxt - tp->copied_seq >= target)
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			mask |= POLLIN | POLLRDNORM;

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

				/* Race breaker. If space is freed after
				 * wspace test but before the flags are set,
				 * IO signal will be lost.
				 */
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				if (sk_stream_is_writeable(sk))
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					mask |= POLLOUT | POLLWRNORM;
			}
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		} else
			mask |= POLLOUT | POLLWRNORM;
L
Linus Torvalds 已提交
531 532 533 534

		if (tp->urg_data & TCP_URG_VALID)
			mask |= POLLPRI;
	}
T
Tom Marshall 已提交
535 536
	/* This barrier is coupled with smp_wmb() in tcp_reset() */
	smp_rmb();
537
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
T
Tom Marshall 已提交
538 539
		mask |= POLLERR;

L
Linus Torvalds 已提交
540 541
	return mask;
}
E
Eric Dumazet 已提交
542
EXPORT_SYMBOL(tcp_poll);
L
Linus Torvalds 已提交
543 544 545 546 547

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
548
	bool slow;
L
Linus Torvalds 已提交
549 550 551 552 553 554

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

E
Eric Dumazet 已提交
555
		slow = lock_sock_fast(sk);
L
Linus Torvalds 已提交
556 557 558 559 560 561
		if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
			answ = 0;
		else if (sock_flag(sk, SOCK_URGINLINE) ||
			 !tp->urg_data ||
			 before(tp->urg_seq, tp->copied_seq) ||
			 !before(tp->urg_seq, tp->rcv_nxt)) {
562

L
Linus Torvalds 已提交
563 564
			answ = tp->rcv_nxt - tp->copied_seq;

E
Eric Dumazet 已提交
565 566 567
			/* Subtract 1, if FIN was received */
			if (answ && sock_flag(sk, SOCK_DONE))
				answ--;
L
Linus Torvalds 已提交
568 569
		} else
			answ = tp->urg_seq - tp->copied_seq;
E
Eric Dumazet 已提交
570
		unlock_sock_fast(sk, slow);
L
Linus Torvalds 已提交
571 572 573 574 575 576 577 578 579 580 581 582 583
		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;
584 585 586 587 588 589 590 591 592
	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
593 594
	default:
		return -ENOIOCTLCMD;
595
	}
L
Linus Torvalds 已提交
596 597 598

	return put_user(answ, (int __user *)arg);
}
E
Eric Dumazet 已提交
599
EXPORT_SYMBOL(tcp_ioctl);
L
Linus Torvalds 已提交
600 601 602

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
603
	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
L
Linus Torvalds 已提交
604 605 606
	tp->pushed_seq = tp->write_seq;
}

E
Eric Dumazet 已提交
607
static inline bool forced_push(const struct tcp_sock *tp)
L
Linus Torvalds 已提交
608 609 610 611
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

612
static void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
613
{
614
	struct tcp_sock *tp = tcp_sk(sk);
615 616 617 618
	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
619
	tcb->tcp_flags = TCPHDR_ACK;
620
	tcb->sacked  = 0;
621
	__skb_header_release(skb);
622
	tcp_add_write_queue_tail(sk, skb);
623 624
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
625
	if (tp->nonagle & TCP_NAGLE_PUSH)
626
		tp->nonagle &= ~TCP_NAGLE_PUSH;
L
Linus Torvalds 已提交
627 628
}

629
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
630
{
I
Ilpo Järvinen 已提交
631
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
632 633 634
		tp->snd_up = tp->write_seq;
}

E
Eric Dumazet 已提交
635
/* If a not yet filled skb is pushed, do not send it if
636
 * we have data packets in Qdisc or NIC queues :
E
Eric Dumazet 已提交
637 638 639 640
 * 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
641 642 643
 * 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
644 645 646
 */
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
				int size_goal)
L
Linus Torvalds 已提交
647
{
E
Eric Dumazet 已提交
648 649
	return skb->len < size_goal &&
	       sysctl_tcp_autocorking &&
650
	       skb != tcp_write_queue_head(sk) &&
E
Eric Dumazet 已提交
651 652 653 654 655 656 657 658
	       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;
659

E
Eric Dumazet 已提交
660 661
	if (!tcp_send_head(sk))
		return;
662

E
Eric Dumazet 已提交
663 664 665 666 667 668 669 670 671 672 673 674 675
	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);
		}
676 677 678 679 680
		/* 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
681
	}
E
Eric Dumazet 已提交
682 683 684 685 686

	if (flags & MSG_MORE)
		nonagle = TCP_NAGLE_CORK;

	__tcp_push_pending_frames(sk, mss_now, nonagle);
L
Linus Torvalds 已提交
687 688
}

689 690
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
691 692
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
693
	int ret;
J
Jens Axboe 已提交
694

695 696
	ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
			      tss->flags);
697 698 699
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
700 701 702 703 704 705 706
}

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,
707
		.count	  = tss->len,
J
Jens Axboe 已提交
708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738
	};

	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;

739
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
740 741 742 743 744 745 746 747 748 749
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

750
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788
	while (tss.len) {
		ret = __tcp_splice_read(sk, &tss);
		if (ret < 0)
			break;
		else if (!ret) {
			if (spliced)
				break;
			if (sock_flag(sk, SOCK_DONE))
				break;
			if (sk->sk_err) {
				ret = sock_error(sk);
				break;
			}
			if (sk->sk_shutdown & RCV_SHUTDOWN)
				break;
			if (sk->sk_state == TCP_CLOSE) {
				/*
				 * This occurs when user tries to read
				 * from never connected socket.
				 */
				if (!sock_flag(sk, SOCK_DONE))
					ret = -ENOTCONN;
				break;
			}
			if (!timeo) {
				ret = -EAGAIN;
				break;
			}
			sk_wait_data(sk, &timeo);
			if (signal_pending(current)) {
				ret = sock_intr_errno(timeo);
				break;
			}
			continue;
		}
		tss.len -= ret;
		spliced += ret;

789 790
		if (!timeo)
			break;
J
Jens Axboe 已提交
791 792 793 794
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
795
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
796 797 798 799 800 801 802 803 804 805 806
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
807
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
808

809
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
810 811 812 813 814 815 816 817
{
	struct sk_buff *skb;

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

	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
	if (skb) {
818
		if (sk_wmem_schedule(sk, skb->truesize)) {
819
			skb_reserve(skb, sk->sk_prot->max_header);
820 821 822 823
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
E
Eric Dumazet 已提交
824
			skb->reserved_tailroom = skb->end - skb->tail - size;
825 826 827 828
			return skb;
		}
		__kfree_skb(skb);
	} else {
829
		sk->sk_prot->enter_memory_pressure(sk);
830 831 832 833 834
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
835 836 837 838
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
839
	u32 xmit_size_goal, old_size_goal;
I
Ilpo Järvinen 已提交
840 841 842 843

	xmit_size_goal = mss_now;

	if (large_allowed && sk_can_gso(sk)) {
E
Eric Dumazet 已提交
844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862
		u32 gso_size, hlen;

		/* Maybe we should/could use sk->sk_prot->max_header here ? */
		hlen = inet_csk(sk)->icsk_af_ops->net_header_len +
		       inet_csk(sk)->icsk_ext_hdr_len +
		       tp->tcp_header_len;

		/* Goal is to send at least one packet per ms,
		 * not one big TSO packet every 100 ms.
		 * This preserves ACK clocking and is consistent
		 * with tcp_tso_should_defer() heuristic.
		 */
		gso_size = sk->sk_pacing_rate / (2 * MSEC_PER_SEC);
		gso_size = max_t(u32, gso_size,
				 sysctl_tcp_min_tso_segs * mss_now);

		xmit_size_goal = min_t(u32, gso_size,
				       sk->sk_gso_max_size - 1 - hlen);

I
Ilpo Järvinen 已提交
863
		xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
864 865 866 867 868 869 870 871

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

		if (likely(old_size_goal <= xmit_size_goal &&
			   old_size_goal + mss_now > xmit_size_goal)) {
			xmit_size_goal = old_size_goal;
		} else {
872 873 874
			tp->xmit_size_goal_segs =
				min_t(u16, xmit_size_goal / mss_now,
				      sk->sk_gso_max_segs);
875 876
			xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
		}
I
Ilpo Järvinen 已提交
877 878
	}

879
	return max(xmit_size_goal, mss_now);
I
Ilpo Järvinen 已提交
880 881 882 883 884 885 886 887 888 889 890 891
}

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;
}

892 893
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
894 895
{
	struct tcp_sock *tp = tcp_sk(sk);
896
	int mss_now, size_goal;
L
Linus Torvalds 已提交
897 898 899 900
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

901 902 903 904 905 906
	/* Wait for a connection to finish. One exception is TCP Fast Open
	 * (passive side) where data is allowed to be sent before a connection
	 * is fully established.
	 */
	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
	    !tcp_passive_fastopen(sk)) {
L
Linus Torvalds 已提交
907 908
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_err;
909
	}
L
Linus Torvalds 已提交
910 911 912

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

I
Ilpo Järvinen 已提交
913
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
914 915 916 917
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
918
		goto out_err;
L
Linus Torvalds 已提交
919

920
	while (size > 0) {
921
		struct sk_buff *skb = tcp_write_queue_tail(sk);
922 923
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
924

925
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
926 927 928 929
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

930
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
L
Linus Torvalds 已提交
931 932 933
			if (!skb)
				goto wait_for_memory;

934
			skb_entail(sk, skb);
935
			copy = size_goal;
L
Linus Torvalds 已提交
936 937 938 939 940 941 942 943 944 945 946
		}

		if (copy > size)
			copy = size;

		i = skb_shinfo(skb)->nr_frags;
		can_coalesce = skb_can_coalesce(skb, i, page, offset);
		if (!can_coalesce && i >= MAX_SKB_FRAGS) {
			tcp_mark_push(tp, skb);
			goto new_segment;
		}
947
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
948
			goto wait_for_memory;
949

L
Linus Torvalds 已提交
950
		if (can_coalesce) {
E
Eric Dumazet 已提交
951
			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
952 953 954 955
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}
956
		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
957

L
Linus Torvalds 已提交
958 959 960 961
		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
962
		sk_mem_charge(sk, copy);
963
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
964 965
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
966
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
967 968

		if (!copied)
E
Eric Dumazet 已提交
969
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
970 971

		copied += copy;
972
		offset += copy;
973 974
		if (!(size -= copy)) {
			tcp_tx_timestamp(sk, skb);
L
Linus Torvalds 已提交
975
			goto out;
976
		}
L
Linus Torvalds 已提交
977

978
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
979 980 981 982
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
983
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
984
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
985 986 987 988 989 990
			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
991 992
		tcp_push(sk, flags & ~MSG_MORE, mss_now,
			 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
993 994 995 996

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

I
Ilpo Järvinen 已提交
997
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
998 999 1000
	}

out:
1001
	if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
E
Eric Dumazet 已提交
1002
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
L
Linus Torvalds 已提交
1003 1004 1005 1006 1007 1008 1009 1010 1011
	return copied;

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

1012 1013
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
1014 1015 1016 1017
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
1018
	    !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
1019 1020
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
1021 1022

	lock_sock(sk);
1023
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
1024 1025 1026
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
1027
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
1028

1029
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
1030
{
1031
	const struct tcp_sock *tp = tcp_sk(sk);
1032
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
1033

K
Krishna Kumar 已提交
1034
	if (sg) {
1035 1036 1037 1038 1039 1040
		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 {
1041 1042 1043 1044 1045 1046 1047
			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
1048 1049 1050 1051

	return tmp;
}

1052 1053 1054 1055 1056 1057 1058 1059
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
	if (tp->fastopen_req != NULL) {
		kfree(tp->fastopen_req);
		tp->fastopen_req = NULL;
	}
}

1060 1061
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
				int *copied, size_t size)
1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
{
	struct tcp_sock *tp = tcp_sk(sk);
	int err, flags;

	if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
		return -EOPNOTSUPP;
	if (tp->fastopen_req != NULL)
		return -EALREADY; /* Another Fast Open is in progress */

	tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
				   sk->sk_allocation);
	if (unlikely(tp->fastopen_req == NULL))
		return -ENOBUFS;
	tp->fastopen_req->data = msg;
1076
	tp->fastopen_req->size = size;
1077 1078 1079 1080

	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
	err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
				    msg->msg_namelen, flags);
1081
	*copied = tp->fastopen_req->copied;
1082 1083 1084 1085
	tcp_free_fastopen_req(tp);
	return err;
}

1086
int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
L
Linus Torvalds 已提交
1087 1088 1089 1090 1091
		size_t size)
{
	struct iovec *iov;
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1092 1093
	int iovlen, flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
1094
	bool sg;
L
Linus Torvalds 已提交
1095 1096 1097 1098 1099
	long timeo;

	lock_sock(sk);

	flags = msg->msg_flags;
1100
	if (flags & MSG_FASTOPEN) {
1101
		err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1102 1103 1104 1105 1106 1107 1108
		if (err == -EINPROGRESS && copied_syn > 0)
			goto out;
		else if (err)
			goto out_err;
		offset = copied_syn;
	}

L
Linus Torvalds 已提交
1109 1110
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

1111 1112 1113 1114 1115 1116
	/* Wait for a connection to finish. One exception is TCP Fast Open
	 * (passive side) where data is allowed to be sent before a connection
	 * is fully established.
	 */
	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
	    !tcp_passive_fastopen(sk)) {
L
Linus Torvalds 已提交
1117
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1118
			goto do_error;
1119
	}
L
Linus Torvalds 已提交
1120

P
Pavel Emelyanov 已提交
1121 1122 1123
	if (unlikely(tp->repair)) {
		if (tp->repair_queue == TCP_RECV_QUEUE) {
			copied = tcp_send_rcvq(sk, msg, size);
1124
			goto out_nopush;
P
Pavel Emelyanov 已提交
1125 1126 1127 1128 1129 1130 1131 1132 1133
		}

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

		/* 'common' sending to sendq */
	}

L
Linus Torvalds 已提交
1134 1135 1136
	/* This should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

I
Ilpo Järvinen 已提交
1137
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1138 1139 1140 1141 1142 1143 1144 1145

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

L
Linus Torvalds 已提交
1150
	while (--iovlen >= 0) {
1151
		size_t seglen = iov->iov_len;
L
Linus Torvalds 已提交
1152 1153 1154
		unsigned char __user *from = iov->iov_base;

		iov++;
1155 1156 1157 1158 1159 1160 1161 1162 1163
		if (unlikely(offset > 0)) {  /* Skip bytes copied in SYN */
			if (offset >= seglen) {
				offset -= seglen;
				continue;
			}
			seglen -= offset;
			from += offset;
			offset = 0;
		}
L
Linus Torvalds 已提交
1164 1165

		while (seglen > 0) {
1166 1167
			int copy = 0;
			int max = size_goal;
L
Linus Torvalds 已提交
1168

1169
			skb = tcp_write_queue_tail(sk);
1170 1171 1172 1173 1174
			if (tcp_send_head(sk)) {
				if (skb->ip_summed == CHECKSUM_NONE)
					max = mss_now;
				copy = max - skb->len;
			}
L
Linus Torvalds 已提交
1175

1176
			if (copy <= 0) {
L
Linus Torvalds 已提交
1177 1178 1179 1180 1181 1182 1183
new_segment:
				/* Allocate new segment. If the interface is SG,
				 * allocate skb fitting to single page.
				 */
				if (!sk_stream_memory_free(sk))
					goto wait_for_sndbuf;

K
Krishna Kumar 已提交
1184 1185 1186
				skb = sk_stream_alloc_skb(sk,
							  select_size(sk, sg),
							  sk->sk_allocation);
L
Linus Torvalds 已提交
1187 1188 1189 1190 1191 1192
				if (!skb)
					goto wait_for_memory;

				/*
				 * Check whether we can use HW checksum.
				 */
1193
				if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1194
					skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
1195

1196
				skb_entail(sk, skb);
1197
				copy = size_goal;
1198
				max = size_goal;
1199 1200 1201 1202 1203 1204 1205

				/* 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
1206 1207 1208 1209 1210 1211 1212
			}

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

			/* Where to copy to? */
1213
			if (skb_availroom(skb) > 0) {
L
Linus Torvalds 已提交
1214
				/* We have some space in skb head. Superb! */
1215
				copy = min_t(int, copy, skb_availroom(skb));
1216 1217
				err = skb_add_data_nocache(sk, skb, from, copy);
				if (err)
L
Linus Torvalds 已提交
1218 1219
					goto do_fault;
			} else {
1220
				bool merge = true;
L
Linus Torvalds 已提交
1221
				int i = skb_shinfo(skb)->nr_frags;
1222 1223 1224 1225 1226 1227 1228 1229 1230 1231
				struct page_frag *pfrag = sk_page_frag(sk);

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

				if (!skb_can_coalesce(skb, i, pfrag->page,
						      pfrag->offset)) {
					if (i == MAX_SKB_FRAGS || !sg) {
						tcp_mark_push(tp, skb);
						goto new_segment;
L
Linus Torvalds 已提交
1232
					}
1233 1234
					merge = false;
				}
1235

1236
				copy = min_t(int, copy, pfrag->size - pfrag->offset);
1237

1238
				if (!sk_wmem_schedule(sk, copy))
1239
					goto wait_for_memory;
L
Linus Torvalds 已提交
1240

1241
				err = skb_copy_to_page_nocache(sk, from, skb,
1242 1243 1244 1245
							       pfrag->page,
							       pfrag->offset,
							       copy);
				if (err)
L
Linus Torvalds 已提交
1246 1247 1248 1249
					goto do_error;

				/* Update the skb. */
				if (merge) {
E
Eric Dumazet 已提交
1250
					skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
1251
				} else {
1252 1253 1254
					skb_fill_page_desc(skb, i, pfrag->page,
							   pfrag->offset, copy);
					get_page(pfrag->page);
L
Linus Torvalds 已提交
1255
				}
1256
				pfrag->offset += copy;
L
Linus Torvalds 已提交
1257 1258 1259
			}

			if (!copied)
E
Eric Dumazet 已提交
1260
				TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
1261 1262 1263

			tp->write_seq += copy;
			TCP_SKB_CB(skb)->end_seq += copy;
1264
			tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
1265 1266 1267

			from += copy;
			copied += copy;
1268 1269
			if ((seglen -= copy) == 0 && iovlen == 0) {
				tcp_tx_timestamp(sk, skb);
L
Linus Torvalds 已提交
1270
				goto out;
1271
			}
L
Linus Torvalds 已提交
1272

P
Pavel Emelyanov 已提交
1273
			if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1274 1275 1276 1277
				continue;

			if (forced_push(tp)) {
				tcp_mark_push(tp, skb);
1278
				__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1279
			} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
1280 1281 1282 1283 1284 1285
				tcp_push_one(sk, mss_now);
			continue;

wait_for_sndbuf:
			set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
1286
			if (copied)
E
Eric Dumazet 已提交
1287 1288
				tcp_push(sk, flags & ~MSG_MORE, mss_now,
					 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
1289 1290 1291 1292

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

I
Ilpo Järvinen 已提交
1293
			mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1294 1295 1296 1297
		}
	}

out:
1298
	if (copied)
E
Eric Dumazet 已提交
1299
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1300
out_nopush:
L
Linus Torvalds 已提交
1301
	release_sock(sk);
1302
	return copied + copied_syn;
L
Linus Torvalds 已提交
1303 1304 1305

do_fault:
	if (!skb->len) {
1306 1307 1308 1309 1310
		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);
1311
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1312 1313 1314
	}

do_error:
1315
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1316 1317 1318 1319 1320 1321
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1322
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1323 1324 1325 1326 1327 1328

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

1329
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
{
	struct tcp_sock *tp = tcp_sk(sk);

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

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

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

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

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

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

		return err ? -EFAULT : len;
	}

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

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

P
Pavel Emelyanov 已提交
1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390
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) {
		err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
		if (err)
			break;

		copied += skb->len;
	}

	return err ?: copied;
}

L
Linus Torvalds 已提交
1391 1392 1393 1394 1395 1396
/* 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.
 */
1397
void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1398 1399
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1400
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1401 1402 1403

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

1404
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1405
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1406
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1407

1408 1409
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1410 1411
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1412
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1413
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1414
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1415 1416 1417 1418 1419 1420
		    /*
		     * 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.
		     */
1421 1422 1423 1424 1425
		    (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
1426
			time_to_ack = true;
L
Linus Torvalds 已提交
1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447
	}

	/* 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
1448
				time_to_ack = true;
L
Linus Torvalds 已提交
1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459
		}
	}
	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);

1460
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1461 1462 1463 1464 1465

	/* RX process wants to run with disabled BHs, though it is not
	 * necessary */
	local_bh_disable();
	while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
P
Peter Zijlstra 已提交
1466
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1467 1468 1469 1470 1471 1472
	local_bh_enable();

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

1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483
#ifdef CONFIG_NET_DMA
static void tcp_service_net_dma(struct sock *sk, bool wait)
{
	dma_cookie_t done, used;
	dma_cookie_t last_issued;
	struct tcp_sock *tp = tcp_sk(sk);

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

	last_issued = tp->ucopy.dma_cookie;
1484
	dma_async_issue_pending(tp->ucopy.dma_chan);
1485 1486

	do {
1487
		if (dma_async_is_tx_complete(tp->ucopy.dma_chan,
1488
					      last_issued, &done,
1489
					      &used) == DMA_COMPLETE) {
1490 1491 1492 1493 1494 1495 1496
			/* Safe to free early-copied skbs now */
			__skb_queue_purge(&sk->sk_async_wait_queue);
			break;
		} else {
			struct sk_buff *skb;
			while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
			       (dma_async_is_complete(skb->dma_cookie, done,
1497
						      used) == DMA_COMPLETE)) {
1498 1499 1500 1501 1502 1503 1504 1505
				__skb_dequeue(&sk->sk_async_wait_queue);
				kfree_skb(skb);
			}
		}
	} while (wait);
}
#endif

1506
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
L
Linus Torvalds 已提交
1507 1508 1509 1510
{
	struct sk_buff *skb;
	u32 offset;

1511
	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
L
Linus Torvalds 已提交
1512
		offset = seq - TCP_SKB_CB(skb)->seq;
1513
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1514
			offset--;
1515
		if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
L
Linus Torvalds 已提交
1516 1517 1518
			*off = offset;
			return skb;
		}
1519 1520 1521 1522 1523
		/* This looks weird, but this can happen if TCP collapsing
		 * splitted a fat GRO packet, while we released socket lock
		 * in skb_splice_bits()
		 */
		sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551
	}
	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) {
1552 1553
			int used;
			size_t len;
L
Linus Torvalds 已提交
1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564

			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);
1565
			if (used <= 0) {
1566 1567 1568 1569
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1570 1571 1572 1573
				seq += used;
				copied += used;
				offset += used;
			}
1574
			/* If recv_actor drops the lock (e.g. TCP splice
1575 1576 1577 1578
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1579 1580
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1581
				break;
1582 1583 1584 1585 1586
			/* 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
1587
		}
1588
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
E
Eric Dumazet 已提交
1589
			sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1590 1591 1592
			++seq;
			break;
		}
E
Eric Dumazet 已提交
1593
		sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1594 1595
		if (!desc->count)
			break;
1596
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1597 1598 1599 1600 1601 1602
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1603 1604
	if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
1605
		tcp_cleanup_rbuf(sk, copied);
1606
	}
L
Linus Torvalds 已提交
1607 1608
	return copied;
}
E
Eric Dumazet 已提交
1609
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630

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

int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len, int nonblock, int flags, int *addr_len)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int copied = 0;
	u32 peek_seq;
	u32 *seq;
	unsigned long used;
	int err;
	int target;		/* Read at least this many bytes */
	long timeo;
	struct task_struct *user_recv = NULL;
E
Eric Dumazet 已提交
1631
	bool copied_early = false;
1632
	struct sk_buff *skb;
I
Ilpo Järvinen 已提交
1633
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1634

1635 1636 1637
	if (unlikely(flags & MSG_ERRQUEUE))
		return ip_recv_error(sk, msg, len, addr_len);

1638 1639 1640
	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
	    (sk->sk_state == TCP_ESTABLISHED))
		sk_busy_loop(sk, nonblock);
1641

L
Linus Torvalds 已提交
1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653
	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
1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668
	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
1669 1670 1671 1672 1673 1674 1675 1676
	seq = &tp->copied_seq;
	if (flags & MSG_PEEK) {
		peek_seq = tp->copied_seq;
		seq = &peek_seq;
	}

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

C
Chris Leech 已提交
1677 1678 1679
#ifdef CONFIG_NET_DMA
	tp->ucopy.dma_chan = NULL;
	preempt_disable();
1680
	skb = skb_peek_tail(&sk->sk_receive_queue);
A
Andrew Morton 已提交
1681 1682 1683 1684 1685 1686 1687 1688
	{
		int available = 0;

		if (skb)
			available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
		if ((available < target) &&
		    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
		    !sysctl_tcp_low_latency &&
1689
		    net_dma_find_channel()) {
1690
			preempt_enable();
A
Andrew Morton 已提交
1691 1692 1693
			tp->ucopy.pinned_list =
					dma_pin_iovec_pages(msg->msg_iov, len);
		} else {
1694
			preempt_enable();
A
Andrew Morton 已提交
1695 1696
		}
	}
C
Chris Leech 已提交
1697 1698
#endif

L
Linus Torvalds 已提交
1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713
	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. */

1714
		skb_queue_walk(&sk->sk_receive_queue, skb) {
L
Linus Torvalds 已提交
1715 1716 1717
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1718
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1719 1720 1721
				 "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
1722
				break;
1723

L
Linus Torvalds 已提交
1724
			offset = *seq - TCP_SKB_CB(skb)->seq;
1725
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1726 1727 1728
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1729
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1730
				goto found_fin_ok;
J
Joe Perches 已提交
1731 1732 1733
			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);
1734
		}
L
Linus Torvalds 已提交
1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745

		/* 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 ||
1746
			    signal_pending(current))
L
Linus Torvalds 已提交
1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781
				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;
			}
		}

1782
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1783

1784
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1785 1786 1787 1788 1789 1790 1791 1792 1793
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
				tp->ucopy.iov = msg->msg_iov;
			}

			tp->ucopy.len = len;

1794 1795
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822

			/* 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.
			 */
1823
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1824 1825 1826 1827 1828
				goto do_prequeue;

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

1829
#ifdef CONFIG_NET_DMA
1830 1831 1832 1833 1834 1835
		if (tp->ucopy.dma_chan) {
			if (tp->rcv_wnd == 0 &&
			    !skb_queue_empty(&sk->sk_async_wait_queue)) {
				tcp_service_net_dma(sk, true);
				tcp_cleanup_rbuf(sk, copied);
			} else
1836
				dma_async_issue_pending(tp->ucopy.dma_chan);
1837
		}
1838
#endif
L
Linus Torvalds 已提交
1839 1840 1841 1842 1843 1844 1845
		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
		} else
			sk_wait_data(sk, &timeo);

C
Chris Leech 已提交
1846
#ifdef CONFIG_NET_DMA
1847
		tcp_service_net_dma(sk, false);  /* Don't block */
C
Chris Leech 已提交
1848 1849 1850
		tp->ucopy.wakeup = 0;
#endif

L
Linus Torvalds 已提交
1851 1852 1853 1854 1855 1856
		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

			if ((chunk = len - tp->ucopy.len) != 0) {
1857
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1858 1859 1860 1861 1862
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1863
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1864 1865 1866 1867
do_prequeue:
				tcp_prequeue_process(sk);

				if ((chunk = len - tp->ucopy.len) != 0) {
1868
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1869 1870 1871 1872 1873
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1874 1875
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1876 1877 1878
			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
1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895
			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
1896
						urg_hole++;
L
Linus Torvalds 已提交
1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
C
Chris Leech 已提交
1908 1909
#ifdef CONFIG_NET_DMA
			if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1910
				tp->ucopy.dma_chan = net_dma_find_channel();
C
Chris Leech 已提交
1911 1912 1913 1914 1915 1916 1917 1918 1919

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

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

1920 1921
					pr_alert("%s: dma_cookie < 0\n",
						 __func__);
C
Chris Leech 已提交
1922 1923 1924 1925 1926 1927

					/* Exception. Bailout! */
					if (!copied)
						copied = -EFAULT;
					break;
				}
1928

1929
				dma_async_issue_pending(tp->ucopy.dma_chan);
1930

C
Chris Leech 已提交
1931
				if ((offset + used) == skb->len)
E
Eric Dumazet 已提交
1932
					copied_early = true;
C
Chris Leech 已提交
1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944

			} else
#endif
			{
				err = skb_copy_datagram_iovec(skb, offset,
						msg->msg_iov, used);
				if (err) {
					/* Exception. Bailout! */
					if (!copied)
						copied = -EFAULT;
					break;
				}
L
Linus Torvalds 已提交
1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956
			}
		}

		*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;
1957
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1958 1959 1960 1961
		}
		if (used + offset < skb->len)
			continue;

1962
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1963
			goto found_fin_ok;
C
Chris Leech 已提交
1964 1965
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
E
Eric Dumazet 已提交
1966
			copied_early = false;
C
Chris Leech 已提交
1967
		}
L
Linus Torvalds 已提交
1968 1969 1970 1971 1972
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
C
Chris Leech 已提交
1973 1974
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
E
Eric Dumazet 已提交
1975
			copied_early = false;
C
Chris Leech 已提交
1976
		}
L
Linus Torvalds 已提交
1977 1978 1979 1980
		break;
	} while (len > 0);

	if (user_recv) {
1981
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1982 1983 1984 1985 1986 1987 1988
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1989
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1990 1991 1992 1993 1994 1995 1996 1997 1998
				len -= chunk;
				copied += chunk;
			}
		}

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

C
Chris Leech 已提交
1999
#ifdef CONFIG_NET_DMA
2000 2001
	tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
	tp->ucopy.dma_chan = NULL;
C
Chris Leech 已提交
2002 2003 2004 2005 2006 2007 2008

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

L
Linus Torvalds 已提交
2009 2010 2011 2012 2013
	/* 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. */
2014
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
2015 2016 2017 2018 2019 2020 2021 2022 2023

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
2024
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
2025
	goto out;
P
Pavel Emelyanov 已提交
2026 2027 2028 2029

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
2030
}
E
Eric Dumazet 已提交
2031
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
2032

I
Ilpo Järvinen 已提交
2033 2034 2035 2036 2037 2038 2039
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
2040
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
2041 2042 2043 2044
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
2045
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
2046 2047 2048 2049

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2050
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
2051 2052
		/* fall through */
	default:
2053
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
2054
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
2055 2056 2057 2058 2059 2060 2061 2062
	}

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

#ifdef STATE_TRACE
2063
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
2064 2065 2066 2067
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
2068 2069 2070 2071 2072 2073 2074
/*
 *	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.
 */

2075
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102
  /* current state:        new state:      action:	*/
  /* (Invalid)		*/ TCP_CLOSE,
  /* TCP_ESTABLISHED	*/ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  /* TCP_SYN_SENT	*/ TCP_CLOSE,
  /* TCP_SYN_RECV	*/ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  /* TCP_FIN_WAIT1	*/ TCP_FIN_WAIT1,
  /* TCP_FIN_WAIT2	*/ TCP_FIN_WAIT2,
  /* TCP_TIME_WAIT	*/ TCP_CLOSE,
  /* TCP_CLOSE		*/ TCP_CLOSE,
  /* TCP_CLOSE_WAIT	*/ TCP_LAST_ACK  | TCP_ACTION_FIN,
  /* TCP_LAST_ACK	*/ TCP_LAST_ACK,
  /* TCP_LISTEN		*/ TCP_CLOSE,
  /* TCP_CLOSING	*/ TCP_CLOSING,
};

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

	tcp_set_state(sk, ns);

	return next & TCP_ACTION_FIN;
}

/*
 *	Shutdown the sending side of a connection. Much like close except
2103
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123
 */

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
2124
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
2125

A
Arun Sharma 已提交
2126 2127 2128 2129 2130 2131 2132
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);

2133 2134 2135 2136
	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
2137 2138 2139
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
2140 2141 2142 2143
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
2144
	int state;
L
Linus Torvalds 已提交
2145 2146 2147 2148 2149 2150 2151 2152

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

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

		/* Special case. */
2153
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2154 2155 2156 2157 2158 2159 2160 2161 2162

		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) {
2163 2164 2165 2166
		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
2167 2168 2169 2170
		data_was_unread += len;
		__kfree_skb(skb);
	}

2171
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2172

2173 2174 2175 2176
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2177 2178 2179 2180 2181 2182
	/* 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
2183
	 */
P
Pavel Emelyanov 已提交
2184 2185 2186
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2187
		/* Unread data was tossed, zap the connection. */
2188
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2189
		tcp_set_state(sk, TCP_CLOSE);
2190
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2191 2192 2193
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2194
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
	} 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
2220 2221 2222 2223
		 * 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
2224 2225 2226 2227 2228 2229 2230
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2231 2232 2233 2234
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2235 2236 2237 2238 2239 2240 2241 2242 2243
	/* 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);
2244
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2245

H
Herbert Xu 已提交
2246 2247
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2248 2249 2250
	/* 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
2251 2252 2253 2254

	/*	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.
2255
	 *	We use a 1 minute timeout (about the same as BSD) then kill
L
Linus Torvalds 已提交
2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270
	 *	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);
2271 2272
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2273
		} else {
2274
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2275 2276

			if (tmo > TCP_TIMEWAIT_LEN) {
2277 2278
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2279 2280 2281 2282 2283 2284 2285
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2286
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2287
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2288 2289
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2290 2291
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2292 2293 2294
		}
	}

2295 2296 2297 2298 2299 2300 2301 2302
	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.
		 */
		if (req != NULL)
			reqsk_fastopen_remove(sk, req, false);
2303
		inet_csk_destroy_sock(sk);
2304
	}
L
Linus Torvalds 已提交
2305 2306 2307 2308 2309 2310 2311
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2312
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2313 2314 2315

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

E
Eric Dumazet 已提交
2316
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2317 2318 2319 2320 2321 2322 2323 2324 2325
{
	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);
2326
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2327 2328 2329 2330 2331 2332 2333 2334 2335
	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) {
2336
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2337 2338
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2339 2340 2341
	} 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
2342
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2343 2344 2345 2346 2347 2348 2349 2350 2351
		 * 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);
2352
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2353
	__skb_queue_purge(&tp->out_of_order_queue);
C
Chris Leech 已提交
2354 2355 2356
#ifdef CONFIG_NET_DMA
	__skb_queue_purge(&sk->sk_async_wait_queue);
#endif
L
Linus Torvalds 已提交
2357

E
Eric Dumazet 已提交
2358
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2359 2360 2361 2362 2363 2364

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

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
2365
	tp->srtt_us = 0;
L
Linus Torvalds 已提交
2366 2367
	if ((tp->write_seq += tp->max_window + 2) == 0)
		tp->write_seq = 1;
2368
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2369
	tp->snd_cwnd = 2;
2370
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2371
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2372
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2373
	tp->snd_cwnd_cnt = 0;
2374
	tp->window_clamp = 0;
2375
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2376
	tcp_clear_retrans(tp);
2377
	inet_csk_delack_init(sk);
2378
	tcp_init_send_head(sk);
2379
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2380 2381
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2382
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2383 2384 2385 2386

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2387
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2388

2389 2390 2391 2392 2393 2394 2395
void tcp_sock_destruct(struct sock *sk)
{
	inet_sock_destruct(sk);

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

E
Eric Dumazet 已提交
2396
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2397
{
2398
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2399 2400 2401
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2402 2403
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2404
{
2405
	struct tcp_repair_opt opt;
2406

2407 2408
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2409 2410 2411
			return -EFAULT;

		optbuf++;
2412
		len -= sizeof(opt);
2413

2414 2415 2416
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2417
			break;
2418
		case TCPOPT_WINDOW:
2419 2420 2421 2422 2423 2424
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2425

2426 2427 2428 2429
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2430 2431
			break;
		case TCPOPT_SACK_PERM:
2432 2433 2434
			if (opt.opt_val != 0)
				return -EINVAL;

2435 2436 2437 2438 2439
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2440 2441 2442
			if (opt.opt_val != 0)
				return -EINVAL;

2443 2444 2445 2446 2447 2448 2449 2450
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

L
Linus Torvalds 已提交
2451 2452 2453
/*
 *	Socket option code for TCP.
 */
2454
static int do_tcp_setsockopt(struct sock *sk, int level,
2455
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2456 2457
{
	struct tcp_sock *tp = tcp_sk(sk);
2458
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2459 2460 2461
	int val;
	int err = 0;

2462 2463 2464
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2465 2466 2467 2468 2469 2470
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2471
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2472 2473 2474 2475 2476
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2477
		err = tcp_set_congestion_control(sk, name);
2478 2479 2480
		release_sock(sk);
		return err;
	}
2481 2482 2483
	default:
		/* fallthru */
		break;
2484
	}
2485

L
Linus Torvalds 已提交
2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498
	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 */
2499
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516
			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;
2517
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2518 2519 2520 2521 2522
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2523 2524 2525 2526 2527 2528 2529
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2530 2531 2532
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
2533
		else {
A
Andreas Petlund 已提交
2534
			tp->thin_dupack = val;
Y
Yuchung Cheng 已提交
2535 2536
			if (tp->thin_dupack)
				tcp_disable_early_retrans(tp);
2537
		}
A
Andreas Petlund 已提交
2538 2539
		break;

P
Pavel Emelyanov 已提交
2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575
	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;

2576 2577 2578 2579
	case TCP_REPAIR_OPTIONS:
		if (!tp->repair)
			err = -EINVAL;
		else if (sk->sk_state == TCP_ESTABLISHED)
2580 2581 2582
			err = tcp_repair_options_est(tp,
					(struct tcp_repair_opt __user *)optval,
					optlen);
2583 2584 2585 2586
		else
			err = -EPERM;
		break;

L
Linus Torvalds 已提交
2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604
	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;
2605
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616
		}
		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))) {
2617
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2618 2619 2620 2621
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2622
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641
			}
		}
		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
2642
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654
		break;

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

	case TCP_DEFER_ACCEPT:
2655 2656 2657 2658
		/* 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
2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674
		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) {
2675
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2676
		} else {
2677
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2678 2679
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2680 2681
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2682
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2683
				if (!(val & 1))
2684
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2685 2686 2687 2688
			}
		}
		break;

2689 2690 2691 2692 2693 2694
#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
2695 2696 2697 2698
	case TCP_USER_TIMEOUT:
		/* Cap the max timeout in ms TCP will retry/retrans
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2699 2700 2701 2702
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2703
		break;
2704 2705 2706 2707 2708 2709 2710 2711

	case TCP_FASTOPEN:
		if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
		    TCPF_LISTEN)))
			err = fastopen_init_queue(sk, val);
		else
			err = -EINVAL;
		break;
2712 2713 2714 2715 2716 2717
	case TCP_TIMESTAMP:
		if (!tp->repair)
			err = -EPERM;
		else
			tp->tsoffset = val - tcp_time_stamp;
		break;
2718 2719 2720 2721
	case TCP_NOTSENT_LOWAT:
		tp->notsent_lowat = val;
		sk->sk_write_space(sk);
		break;
L
Linus Torvalds 已提交
2722 2723 2724
	default:
		err = -ENOPROTOOPT;
		break;
2725 2726
	}

L
Linus Torvalds 已提交
2727 2728 2729 2730
	release_sock(sk);
	return err;
}

2731
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2732
		   unsigned int optlen)
2733
{
2734
	const struct inet_connection_sock *icsk = inet_csk(sk);
2735 2736 2737 2738 2739 2740

	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
2741
EXPORT_SYMBOL(tcp_setsockopt);
2742 2743

#ifdef CONFIG_COMPAT
2744
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2745
			  char __user *optval, unsigned int optlen)
2746
{
2747 2748 2749
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2750 2751
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2752
EXPORT_SYMBOL(compat_tcp_setsockopt);
2753 2754
#endif

L
Linus Torvalds 已提交
2755
/* Return information about state of tcp endpoint in API format. */
2756
void tcp_get_info(const struct sock *sk, struct tcp_info *info)
L
Linus Torvalds 已提交
2757
{
2758
	const struct tcp_sock *tp = tcp_sk(sk);
2759
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2760 2761 2762 2763 2764
	u32 now = tcp_time_stamp;

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

	info->tcpi_state = sk->sk_state;
2765
	info->tcpi_ca_state = icsk->icsk_ca_state;
2766
	info->tcpi_retransmits = icsk->icsk_retransmits;
2767
	info->tcpi_probes = icsk->icsk_probes_out;
2768
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2769 2770 2771

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2772
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2773 2774 2775 2776 2777
		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;
2778
	}
L
Linus Torvalds 已提交
2779

E
Eric Dumazet 已提交
2780
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2781
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2782 2783
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2784 2785
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2786

2787 2788
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2789
	info->tcpi_snd_mss = tp->mss_cache;
2790
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2791

2792 2793 2794 2795 2796 2797 2798
	if (sk->sk_state == TCP_LISTEN) {
		info->tcpi_unacked = sk->sk_ack_backlog;
		info->tcpi_sacked = sk->sk_max_ack_backlog;
	} else {
		info->tcpi_unacked = tp->packets_out;
		info->tcpi_sacked = tp->sacked_out;
	}
L
Linus Torvalds 已提交
2799 2800 2801 2802 2803
	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);
2804
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2805 2806
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2807
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2808
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2809 2810
	info->tcpi_rtt = tp->srtt_us >> 3;
	info->tcpi_rttvar = tp->mdev_us >> 2;
L
Linus Torvalds 已提交
2811 2812 2813 2814 2815 2816 2817 2818 2819
	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;
2820 2821 2822 2823 2824

	info->tcpi_pacing_rate = sk->sk_pacing_rate != ~0U ?
					sk->sk_pacing_rate : ~0ULL;
	info->tcpi_max_pacing_rate = sk->sk_max_pacing_rate != ~0U ?
					sk->sk_max_pacing_rate : ~0ULL;
L
Linus Torvalds 已提交
2825 2826 2827
}
EXPORT_SYMBOL_GPL(tcp_get_info);

2828 2829
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2830
{
2831
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844
	struct tcp_sock *tp = tcp_sk(sk);
	int val, len;

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

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

	if (len < 0)
		return -EINVAL;

	switch (optname) {
	case TCP_MAXSEG:
2845
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2846 2847
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2848 2849
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2850 2851 2852 2853 2854 2855 2856 2857
		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
2858
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2859 2860
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2861
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2862 2863
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2864
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2865 2866
		break;
	case TCP_SYNCNT:
2867
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2868 2869 2870 2871 2872 2873 2874
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2875 2876
		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
2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896
		break;
	case TCP_WINDOW_CLAMP:
		val = tp->window_clamp;
		break;
	case TCP_INFO: {
		struct tcp_info info;

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

		tcp_get_info(sk, &info);

		len = min_t(unsigned int, len, sizeof(info));
		if (put_user(len, optlen))
			return -EFAULT;
		if (copy_to_user(optval, &info, len))
			return -EFAULT;
		return 0;
	}
	case TCP_QUICKACK:
2897
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2898
		break;
2899 2900 2901 2902 2903 2904 2905

	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;
2906
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2907 2908
			return -EFAULT;
		return 0;
2909

2910 2911 2912 2913 2914 2915
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2916

P
Pavel Emelyanov 已提交
2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936
	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;

2937 2938 2939
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
2940 2941 2942 2943 2944 2945 2946 2947

	case TCP_FASTOPEN:
		if (icsk->icsk_accept_queue.fastopenq != NULL)
			val = icsk->icsk_accept_queue.fastopenq->max_qlen;
		else
			val = 0;
		break;

2948 2949 2950
	case TCP_TIMESTAMP:
		val = tcp_time_stamp + tp->tsoffset;
		break;
2951 2952 2953
	case TCP_NOTSENT_LOWAT:
		val = tp->notsent_lowat;
		break;
L
Linus Torvalds 已提交
2954 2955
	default:
		return -ENOPROTOOPT;
2956
	}
L
Linus Torvalds 已提交
2957 2958 2959 2960 2961 2962 2963 2964

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

2965 2966 2967 2968 2969 2970 2971 2972 2973 2974
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
2975
EXPORT_SYMBOL(tcp_getsockopt);
2976 2977

#ifdef CONFIG_COMPAT
2978 2979
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2980
{
2981 2982 2983
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2984 2985
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2986
EXPORT_SYMBOL(compat_tcp_getsockopt);
2987
#endif
L
Linus Torvalds 已提交
2988

2989
#ifdef CONFIG_TCP_MD5SIG
2990 2991
static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool __read_mostly;
static DEFINE_MUTEX(tcp_md5sig_mutex);
2992

2993
static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
2994 2995
{
	int cpu;
2996

2997
	for_each_possible_cpu(cpu) {
2998 2999 3000 3001
		struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);

		if (p->md5_desc.tfm)
			crypto_free_hash(p->md5_desc.tfm);
3002 3003 3004 3005
	}
	free_percpu(pool);
}

3006
static void __tcp_alloc_md5sig_pool(void)
3007 3008
{
	int cpu;
3009
	struct tcp_md5sig_pool __percpu *pool;
3010

3011
	pool = alloc_percpu(struct tcp_md5sig_pool);
3012
	if (!pool)
3013
		return;
3014 3015 3016 3017 3018

	for_each_possible_cpu(cpu) {
		struct crypto_hash *hash;

		hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
3019
		if (IS_ERR_OR_NULL(hash))
3020 3021
			goto out_free;

3022
		per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
3023
	}
3024 3025 3026 3027 3028 3029
	/* before setting tcp_md5sig_pool, we must commit all writes
	 * to memory. See ACCESS_ONCE() in tcp_get_md5sig_pool()
	 */
	smp_wmb();
	tcp_md5sig_pool = pool;
	return;
3030 3031 3032 3033
out_free:
	__tcp_free_md5sig_pool(pool);
}

3034
bool tcp_alloc_md5sig_pool(void)
3035
{
3036 3037 3038 3039 3040 3041 3042
	if (unlikely(!tcp_md5sig_pool)) {
		mutex_lock(&tcp_md5sig_mutex);

		if (!tcp_md5sig_pool)
			__tcp_alloc_md5sig_pool();

		mutex_unlock(&tcp_md5sig_mutex);
3043
	}
3044
	return tcp_md5sig_pool != NULL;
3045 3046 3047
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
3048 3049 3050 3051 3052 3053 3054 3055 3056

/**
 *	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)
3057
{
3058
	struct tcp_md5sig_pool __percpu *p;
E
Eric Dumazet 已提交
3059 3060

	local_bh_disable();
3061
	p = ACCESS_ONCE(tcp_md5sig_pool);
E
Eric Dumazet 已提交
3062
	if (p)
3063
		return __this_cpu_ptr(p);
3064

E
Eric Dumazet 已提交
3065 3066 3067 3068
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
3069

3070
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3071
			const struct tcphdr *th)
3072 3073
{
	struct scatterlist sg;
3074
	struct tcphdr hdr;
3075 3076
	int err;

3077 3078 3079 3080
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

3081
	/* options aren't included in the hash */
3082 3083
	sg_init_one(&sg, &hdr, sizeof(hdr));
	err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3084 3085 3086 3087 3088
	return err;
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3089
			  const struct sk_buff *skb, unsigned int header_len)
3090 3091 3092 3093
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
	struct hash_desc *desc = &hp->md5_desc;
3094 3095 3096
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
3097
	const struct skb_shared_info *shi = skb_shinfo(skb);
3098
	struct sk_buff *frag_iter;
3099 3100 3101 3102 3103 3104 3105 3106 3107

	sg_init_table(&sg, 1);

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

	for (i = 0; i < shi->nr_frags; ++i) {
		const struct skb_frag_struct *f = &shi->frags[i];
E
Eric Dumazet 已提交
3108 3109 3110 3111 3112
		unsigned int offset = f->page_offset;
		struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);

		sg_set_page(&sg, page, skb_frag_size(f),
			    offset_in_page(offset));
E
Eric Dumazet 已提交
3113
		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3114 3115 3116
			return 1;
	}

3117 3118 3119 3120
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3121 3122 3123 3124
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

3125
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3126 3127 3128 3129 3130 3131 3132 3133
{
	struct scatterlist sg;

	sg_init_one(&sg, key->key, key->keylen);
	return crypto_hash_update(&hp->md5_desc, &sg, key->keylen);
}
EXPORT_SYMBOL(tcp_md5_hash_key);

3134 3135
#endif

A
Andi Kleen 已提交
3136 3137
void tcp_done(struct sock *sk)
{
3138 3139
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

3140
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3141
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3142 3143 3144

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
3145 3146
	if (req != NULL)
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
3147 3148 3149 3150 3151 3152 3153 3154 3155 3156

	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);

3157
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3158 3159 3160 3161

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
3162 3163
	ssize_t ret;

L
Linus Torvalds 已提交
3164 3165
	if (!str)
		return 0;
3166 3167 3168 3169 3170

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

L
Linus Torvalds 已提交
3171 3172 3173 3174
	return 1;
}
__setup("thash_entries=", set_thash_entries);

3175
static void tcp_init_mem(void)
3176 3177 3178
{
	unsigned long limit = nr_free_buffer_pages() / 8;
	limit = max(limit, 128UL);
3179 3180 3181
	sysctl_tcp_mem[0] = limit / 4 * 3;
	sysctl_tcp_mem[1] = limit;
	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3182 3183
}

L
Linus Torvalds 已提交
3184 3185 3186
void __init tcp_init(void)
{
	struct sk_buff *skb = NULL;
3187
	unsigned long limit;
3188
	int max_rshare, max_wshare, cnt;
3189
	unsigned int i;
L
Linus Torvalds 已提交
3190

3191
	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
L
Linus Torvalds 已提交
3192

3193
	percpu_counter_init(&tcp_sockets_allocated, 0);
3194
	percpu_counter_init(&tcp_orphan_count, 0);
3195 3196 3197
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3198
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3199 3200 3201 3202 3203 3204

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3205
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3206
		alloc_large_system_hash("TCP established",
3207
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3208
					thash_entries,
E
Eric Dumazet 已提交
3209
					17, /* one slot per 128 KB of memory */
3210
					0,
L
Linus Torvalds 已提交
3211
					NULL,
3212
					&tcp_hashinfo.ehash_mask,
3213
					0,
3214
					thash_entries ? 0 : 512 * 1024);
E
Eric Dumazet 已提交
3215
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3216
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
E
Eric Dumazet 已提交
3217

3218 3219
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3220
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3221
		alloc_large_system_hash("TCP bind",
3222
					sizeof(struct inet_bind_hashbucket),
3223
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3224
					17, /* one slot per 128 KB of memory */
3225
					0,
3226
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3227
					NULL,
3228
					0,
L
Linus Torvalds 已提交
3229
					64 * 1024);
3230
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3231 3232 3233
	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
3234 3235
	}

E
Eric Dumazet 已提交
3236 3237 3238 3239 3240 3241

	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
3242

3243
	tcp_init_mem();
3244
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3245
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3246 3247
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3248

3249
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3250
	sysctl_tcp_wmem[1] = 16*1024;
3251
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3252

3253
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3254
	sysctl_tcp_rmem[1] = 87380;
3255
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3256

3257
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3258
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3259

3260 3261
	tcp_metrics_init();

3262
	tcp_register_congestion_control(&tcp_reno);
3263

E
Eric Dumazet 已提交
3264
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3265
}