tcp.c 82.3 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>
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#include <linux/inet_diag.h>
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#include <linux/init.h>
#include <linux/fs.h>
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#include <linux/skbuff.h>
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#include <linux/scatterlist.h>
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#include <linux/splice.h>
#include <linux/net.h>
#include <linux/socket.h>
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#include <linux/random.h>
#include <linux/bootmem.h>
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#include <linux/highmem.h>
#include <linux/swap.h>
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#include <linux/cache.h>
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#include <linux/err.h>
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#include <linux/crypto.h>
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#include <linux/time.h>
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#include <linux/slab.h>
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#include <net/icmp.h>
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#include <net/inet_common.h>
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#include <net/tcp.h>
#include <net/xfrm.h>
#include <net/ip.h>
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#include <net/sock.h>
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#include <asm/uaccess.h>
#include <asm/ioctls.h>
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#include <net/busy_poll.h>
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int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
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int sysctl_tcp_min_tso_segs __read_mostly = 2;

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int sysctl_tcp_autocorking __read_mostly = 1;

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struct percpu_counter tcp_orphan_count;
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EXPORT_SYMBOL_GPL(tcp_orphan_count);

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

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

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

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

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

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

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

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

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

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

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

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

	/* See draft-stevens-tcpca-spec-01 for discussion of the
	 * initialization of these values.
	 */
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
	tp->snd_cwnd_clamp = ~0;
	tp->mss_cache = TCP_MSS_DEFAULT;
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	u64_stats_init(&tp->syncp);
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	tp->reordering = sysctl_tcp_reordering;
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	tcp_enable_early_retrans(tp);
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	tcp_assign_congestion_control(sk);
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	tp->tsoffset = 0;

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	sk->sk_state = TCP_CLOSE;

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

	icsk->icsk_sync_mss = tcp_sync_mss;

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

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

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

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

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

	mask = 0;

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

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

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

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

		if (tp->urg_data & TCP_URG_VALID)
			mask |= POLLPRI;
	}
T
Tom Marshall 已提交
538 539
	/* This barrier is coupled with smp_wmb() in tcp_reset() */
	smp_rmb();
540
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
T
Tom Marshall 已提交
541 542
		mask |= POLLERR;

L
Linus Torvalds 已提交
543 544
	return mask;
}
E
Eric Dumazet 已提交
545
EXPORT_SYMBOL(tcp_poll);
L
Linus Torvalds 已提交
546 547 548 549 550

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
551
	bool slow;
L
Linus Torvalds 已提交
552 553 554 555 556 557

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

E
Eric Dumazet 已提交
558
		slow = lock_sock_fast(sk);
L
Linus Torvalds 已提交
559 560 561 562 563 564
		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)) {
565

L
Linus Torvalds 已提交
566 567
			answ = tp->rcv_nxt - tp->copied_seq;

E
Eric Dumazet 已提交
568 569 570
			/* Subtract 1, if FIN was received */
			if (answ && sock_flag(sk, SOCK_DONE))
				answ--;
L
Linus Torvalds 已提交
571 572
		} else
			answ = tp->urg_seq - tp->copied_seq;
E
Eric Dumazet 已提交
573
		unlock_sock_fast(sk, slow);
L
Linus Torvalds 已提交
574 575 576 577 578 579 580 581 582 583 584 585 586
		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;
587 588 589 590 591 592 593 594 595
	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
596 597
	default:
		return -ENOIOCTLCMD;
598
	}
L
Linus Torvalds 已提交
599 600 601

	return put_user(answ, (int __user *)arg);
}
E
Eric Dumazet 已提交
602
EXPORT_SYMBOL(tcp_ioctl);
L
Linus Torvalds 已提交
603 604 605

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
606
	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
L
Linus Torvalds 已提交
607 608 609
	tp->pushed_seq = tp->write_seq;
}

E
Eric Dumazet 已提交
610
static inline bool forced_push(const struct tcp_sock *tp)
L
Linus Torvalds 已提交
611 612 613 614
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

615
static void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
616
{
617
	struct tcp_sock *tp = tcp_sk(sk);
618 619 620 621
	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
622
	tcb->tcp_flags = TCPHDR_ACK;
623
	tcb->sacked  = 0;
624
	__skb_header_release(skb);
625
	tcp_add_write_queue_tail(sk, skb);
626 627
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
628
	if (tp->nonagle & TCP_NAGLE_PUSH)
629
		tp->nonagle &= ~TCP_NAGLE_PUSH;
630 631

	tcp_slow_start_after_idle_check(sk);
L
Linus Torvalds 已提交
632 633
}

634
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
635
{
I
Ilpo Järvinen 已提交
636
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
637 638 639
		tp->snd_up = tp->write_seq;
}

E
Eric Dumazet 已提交
640
/* If a not yet filled skb is pushed, do not send it if
641
 * we have data packets in Qdisc or NIC queues :
E
Eric Dumazet 已提交
642 643 644 645
 * 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
646 647 648
 * 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
649 650 651
 */
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
				int size_goal)
L
Linus Torvalds 已提交
652
{
E
Eric Dumazet 已提交
653 654
	return skb->len < size_goal &&
	       sysctl_tcp_autocorking &&
655
	       skb != tcp_write_queue_head(sk) &&
E
Eric Dumazet 已提交
656 657 658 659 660 661 662 663
	       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;
664

E
Eric Dumazet 已提交
665 666
	if (!tcp_send_head(sk))
		return;
667

E
Eric Dumazet 已提交
668 669 670 671 672 673 674 675 676 677 678 679 680
	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);
		}
681 682 683 684 685
		/* 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
686
	}
E
Eric Dumazet 已提交
687 688 689 690 691

	if (flags & MSG_MORE)
		nonagle = TCP_NAGLE_CORK;

	__tcp_push_pending_frames(sk, mss_now, nonagle);
L
Linus Torvalds 已提交
692 693
}

694 695
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
696 697
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
698
	int ret;
J
Jens Axboe 已提交
699

700 701 702
	ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
			      min(rd_desc->count, len), tss->flags,
			      skb_socket_splice);
703 704 705
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
706 707 708 709 710 711 712
}

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,
713
		.count	  = tss->len,
J
Jens Axboe 已提交
714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744
	};

	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;

745
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
746 747 748 749 750 751 752 753 754 755
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

756
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
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
	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;
			}
785
			sk_wait_data(sk, &timeo, NULL);
J
Jens Axboe 已提交
786 787 788 789 790 791 792 793 794
			if (signal_pending(current)) {
				ret = sock_intr_errno(timeo);
				break;
			}
			continue;
		}
		tss.len -= ret;
		spliced += ret;

795 796
		if (!timeo)
			break;
J
Jens Axboe 已提交
797 798 799 800
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
801
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
802 803 804 805 806 807 808 809 810 811 812
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
813
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
814

815 816
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
				    bool force_schedule)
817 818 819 820 821 822
{
	struct sk_buff *skb;

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

823 824 825
	if (unlikely(tcp_under_memory_pressure(sk)))
		sk_mem_reclaim_partial(sk);

826
	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
827
	if (likely(skb)) {
828
		bool mem_scheduled;
829

830 831
		if (force_schedule) {
			mem_scheduled = true;
832 833
			sk_forced_mem_schedule(sk, skb->truesize);
		} else {
834
			mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
835
		}
836
		if (likely(mem_scheduled)) {
837
			skb_reserve(skb, sk->sk_prot->max_header);
838 839 840 841
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
E
Eric Dumazet 已提交
842
			skb->reserved_tailroom = skb->end - skb->tail - size;
843 844 845 846
			return skb;
		}
		__kfree_skb(skb);
	} else {
847
		sk->sk_prot->enter_memory_pressure(sk);
848 849 850 851 852
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
853 854 855 856
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
857
	u32 new_size_goal, size_goal;
E
Eric Dumazet 已提交
858 859 860 861

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

862 863
	/* Note : tcp_tso_autosize() will eventually split this later */
	new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
E
Eric Dumazet 已提交
864 865 866 867 868 869 870 871 872
	new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);

	/* We try hard to avoid divides here */
	size_goal = tp->gso_segs * mss_now;
	if (unlikely(new_size_goal < size_goal ||
		     new_size_goal >= size_goal + mss_now)) {
		tp->gso_segs = min_t(u16, new_size_goal / mss_now,
				     sk->sk_gso_max_segs);
		size_goal = tp->gso_segs * mss_now;
I
Ilpo Järvinen 已提交
873 874
	}

E
Eric Dumazet 已提交
875
	return max(size_goal, mss_now);
I
Ilpo Järvinen 已提交
876 877 878 879 880 881 882 883 884 885 886 887
}

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;
}

888 889
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
890 891
{
	struct tcp_sock *tp = tcp_sk(sk);
892
	int mss_now, size_goal;
L
Linus Torvalds 已提交
893 894 895 896
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

897 898 899 900 901 902
	/* 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)) {
903 904
		err = sk_stream_wait_connect(sk, &timeo);
		if (err != 0)
L
Linus Torvalds 已提交
905
			goto out_err;
906
	}
L
Linus Torvalds 已提交
907 908 909

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

I
Ilpo Järvinen 已提交
910
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
911 912 913 914
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
915
		goto out_err;
L
Linus Torvalds 已提交
916

917
	while (size > 0) {
918
		struct sk_buff *skb = tcp_write_queue_tail(sk);
919 920
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
921

922
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
923 924 925 926
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

927 928
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
L
Linus Torvalds 已提交
929 930 931
			if (!skb)
				goto wait_for_memory;

932
			skb_entail(sk, skb);
933
			copy = size_goal;
L
Linus Torvalds 已提交
934 935 936 937 938 939 940 941 942 943 944
		}

		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;
		}
945
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
946
			goto wait_for_memory;
947

L
Linus Torvalds 已提交
948
		if (can_coalesce) {
E
Eric Dumazet 已提交
949
			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
950 951 952 953
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}
954
		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
955

L
Linus Torvalds 已提交
956 957 958 959
		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
960
		sk_mem_charge(sk, copy);
961
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
962 963
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
964
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
965 966

		if (!copied)
E
Eric Dumazet 已提交
967
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
968 969

		copied += copy;
970
		offset += copy;
971 972
		size -= copy;
		if (!size) {
973
			tcp_tx_timestamp(sk, skb);
L
Linus Torvalds 已提交
974
			goto out;
975
		}
L
Linus Torvalds 已提交
976

977
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
978 979 980 981
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
982
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
983
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
984 985 986 987 988 989
			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
990 991
		tcp_push(sk, flags & ~MSG_MORE, mss_now,
			 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
992

993 994
		err = sk_stream_wait_memory(sk, &timeo);
		if (err != 0)
L
Linus Torvalds 已提交
995 996
			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
	return copied;

do_error:
	if (copied)
		goto out;
out_err:
1009 1010 1011
	/* make sure we wake any epoll edge trigger waiter */
	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
		sk->sk_write_space(sk);
L
Linus Torvalds 已提交
1012 1013 1014
	return sk_stream_error(sk, flags, err);
}

1015 1016
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
1017 1018 1019 1020
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
1021
	    !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
1022 1023
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
1024 1025

	lock_sock(sk);
1026
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
1027 1028 1029
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
1030
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
1031

1032
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
1033
{
1034
	const struct tcp_sock *tp = tcp_sk(sk);
1035
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
1036

K
Krishna Kumar 已提交
1037
	if (sg) {
1038 1039 1040 1041 1042 1043
		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 {
1044 1045 1046 1047 1048 1049 1050
			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
1051 1052 1053 1054

	return tmp;
}

1055 1056
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
1057
	if (tp->fastopen_req) {
1058 1059 1060 1061 1062
		kfree(tp->fastopen_req);
		tp->fastopen_req = NULL;
	}
}

1063 1064
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
				int *copied, size_t size)
1065 1066 1067 1068 1069 1070
{
	struct tcp_sock *tp = tcp_sk(sk);
	int err, flags;

	if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
		return -EOPNOTSUPP;
1071
	if (tp->fastopen_req)
1072 1073 1074 1075
		return -EALREADY; /* Another Fast Open is in progress */

	tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
				   sk->sk_allocation);
1076
	if (unlikely(!tp->fastopen_req))
1077 1078
		return -ENOBUFS;
	tp->fastopen_req->data = msg;
1079
	tp->fastopen_req->size = size;
1080 1081 1082 1083

	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
	err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
				    msg->msg_namelen, flags);
1084
	*copied = tp->fastopen_req->copied;
1085 1086 1087 1088
	tcp_free_fastopen_req(tp);
	return err;
}

1089
int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
L
Linus Torvalds 已提交
1090 1091 1092
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1093 1094
	int flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0;
1095
	bool sg;
L
Linus Torvalds 已提交
1096 1097 1098 1099 1100
	long timeo;

	lock_sock(sk);

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

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)) {
1117 1118
		err = sk_stream_wait_connect(sk, &timeo);
		if (err != 0)
1119
			goto do_error;
1120
	}
L
Linus Torvalds 已提交
1121

P
Pavel Emelyanov 已提交
1122 1123 1124
	if (unlikely(tp->repair)) {
		if (tp->repair_queue == TCP_RECV_QUEUE) {
			copied = tcp_send_rcvq(sk, msg, size);
1125
			goto out_nopush;
P
Pavel Emelyanov 已提交
1126 1127 1128 1129 1130 1131 1132 1133 1134
		}

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

		/* 'common' sending to sendq */
	}

L
Linus Torvalds 已提交
1135 1136 1137
	/* This should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

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

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

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1145
		goto out_err;
L
Linus Torvalds 已提交
1146

1147
	sg = !!(sk->sk_route_caps & NETIF_F_SG);
K
Krishna Kumar 已提交
1148

A
Al Viro 已提交
1149
	while (msg_data_left(msg)) {
1150 1151
		int copy = 0;
		int max = size_goal;
L
Linus Torvalds 已提交
1152

1153 1154 1155 1156 1157
		skb = tcp_write_queue_tail(sk);
		if (tcp_send_head(sk)) {
			if (skb->ip_summed == CHECKSUM_NONE)
				max = mss_now;
			copy = max - skb->len;
1158
		}
L
Linus Torvalds 已提交
1159

1160
		if (copy <= 0) {
L
Linus Torvalds 已提交
1161
new_segment:
1162 1163 1164 1165 1166
			/* Allocate new segment. If the interface is SG,
			 * allocate skb fitting to single page.
			 */
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;
L
Linus Torvalds 已提交
1167

1168 1169
			skb = sk_stream_alloc_skb(sk,
						  select_size(sk, sg),
1170 1171
						  sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
1172 1173
			if (!skb)
				goto wait_for_memory;
L
Linus Torvalds 已提交
1174

1175 1176 1177 1178 1179
			/*
			 * Check whether we can use HW checksum.
			 */
			if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
				skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
1180

1181 1182 1183
			skb_entail(sk, skb);
			copy = size_goal;
			max = size_goal;
1184

1185 1186 1187 1188 1189 1190 1191
			/* 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
1192

1193
		/* Try to append data to the end of skb. */
A
Al Viro 已提交
1194 1195
		if (copy > msg_data_left(msg))
			copy = msg_data_left(msg);
1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210

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

			if (!sk_page_frag_refill(sk, pfrag))
				goto wait_for_memory;
1211

1212 1213 1214 1215 1216
			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
1217
				}
1218
				merge = false;
L
Linus Torvalds 已提交
1219 1220
			}

1221 1222 1223 1224
			copy = min_t(int, copy, pfrag->size - pfrag->offset);

			if (!sk_wmem_schedule(sk, copy))
				goto wait_for_memory;
L
Linus Torvalds 已提交
1225

1226 1227 1228 1229 1230 1231
			err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
						       pfrag->page,
						       pfrag->offset,
						       copy);
			if (err)
				goto do_error;
L
Linus Torvalds 已提交
1232

1233 1234 1235 1236 1237 1238 1239
			/* Update the skb. */
			if (merge) {
				skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
			} else {
				skb_fill_page_desc(skb, i, pfrag->page,
						   pfrag->offset, copy);
				get_page(pfrag->page);
1240
			}
1241 1242 1243 1244 1245 1246 1247 1248 1249
			pfrag->offset += copy;
		}

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

		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
1250

1251
		copied += copy;
A
Al Viro 已提交
1252
		if (!msg_data_left(msg)) {
1253 1254 1255
			tcp_tx_timestamp(sk, skb);
			goto out;
		}
L
Linus Torvalds 已提交
1256

1257
		if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1258 1259
			continue;

1260 1261 1262 1263 1264 1265 1266
		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
		} else if (skb == tcp_send_head(sk))
			tcp_push_one(sk, mss_now);
		continue;

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

1274 1275
		err = sk_stream_wait_memory(sk, &timeo);
		if (err != 0)
1276
			goto do_error;
L
Linus Torvalds 已提交
1277

1278
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1279 1280 1281
	}

out:
1282
	if (copied)
E
Eric Dumazet 已提交
1283
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1284
out_nopush:
L
Linus Torvalds 已提交
1285
	release_sock(sk);
1286
	return copied + copied_syn;
L
Linus Torvalds 已提交
1287 1288 1289

do_fault:
	if (!skb->len) {
1290 1291 1292 1293 1294
		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);
1295
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1296 1297 1298
	}

do_error:
1299
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1300 1301 1302
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
1303 1304 1305
	/* make sure we wake any epoll edge trigger waiter */
	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
		sk->sk_write_space(sk);
L
Linus Torvalds 已提交
1306 1307 1308
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1309
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1310 1311 1312 1313 1314 1315

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

1316
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
{
	struct tcp_sock *tp = tcp_sk(sk);

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

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

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

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

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

		if (len > 0) {
			if (!(flags & MSG_TRUNC))
A
Al Viro 已提交
1340
				err = memcpy_to_msg(msg, &c, 1);
L
Linus Torvalds 已提交
1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359
			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
1360 1361 1362 1363 1364 1365 1366 1367
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) {
1368
		err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
P
Pavel Emelyanov 已提交
1369 1370 1371 1372 1373 1374 1375 1376 1377
		if (err)
			break;

		copied += skb->len;
	}

	return err ?: copied;
}

L
Linus Torvalds 已提交
1378 1379 1380 1381 1382 1383
/* 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.
 */
1384
static void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1385 1386
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1387
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1388 1389 1390

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

1391
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1392
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1393
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1394

1395 1396
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1397 1398
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1399
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1400
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1401
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1402 1403 1404 1405 1406 1407
		    /*
		     * 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.
		     */
1408 1409 1410 1411 1412
		    (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
1413
			time_to_ack = true;
L
Linus Torvalds 已提交
1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434
	}

	/* 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
1435
				time_to_ack = true;
L
Linus Torvalds 已提交
1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446
		}
	}
	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);

1447
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1448 1449 1450 1451 1452

	/* 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
1453
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1454 1455 1456 1457 1458 1459
	local_bh_enable();

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

1460
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
L
Linus Torvalds 已提交
1461 1462 1463 1464
{
	struct sk_buff *skb;
	u32 offset;

1465
	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
L
Linus Torvalds 已提交
1466
		offset = seq - TCP_SKB_CB(skb)->seq;
1467
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1468
			offset--;
1469
		if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
L
Linus Torvalds 已提交
1470 1471 1472
			*off = offset;
			return skb;
		}
1473 1474 1475 1476
		/* This looks weird, but this can happen if TCP collapsing
		 * splitted a fat GRO packet, while we released socket lock
		 * in skb_splice_bits()
		 */
D
Dan Williams 已提交
1477
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505
	}
	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) {
1506 1507
			int used;
			size_t len;
L
Linus Torvalds 已提交
1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518

			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);
1519
			if (used <= 0) {
1520 1521 1522 1523
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1524 1525 1526 1527
				seq += used;
				copied += used;
				offset += used;
			}
1528
			/* If recv_actor drops the lock (e.g. TCP splice
1529 1530 1531 1532
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1533 1534
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1535
				break;
1536 1537 1538 1539 1540
			/* 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
1541
		}
1542
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
D
Dan Williams 已提交
1543
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1544 1545 1546
			++seq;
			break;
		}
D
Dan Williams 已提交
1547
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1548 1549
		if (!desc->count)
			break;
1550
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1551 1552 1553 1554 1555 1556
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1557 1558
	if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
1559
		tcp_cleanup_rbuf(sk, copied);
1560
	}
L
Linus Torvalds 已提交
1561 1562
	return copied;
}
E
Eric Dumazet 已提交
1563
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1564 1565 1566 1567 1568 1569 1570 1571 1572

/*
 *	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.
 */

1573 1574
int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
		int flags, int *addr_len)
L
Linus Torvalds 已提交
1575 1576 1577 1578 1579 1580 1581 1582 1583 1584
{
	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;
1585
	struct sk_buff *skb, *last;
I
Ilpo Järvinen 已提交
1586
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1587

1588
	if (unlikely(flags & MSG_ERRQUEUE))
1589
		return inet_recv_error(sk, msg, len, addr_len);
1590

1591 1592 1593
	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
	    (sk->sk_state == TCP_ESTABLISHED))
		sk_busy_loop(sk, nonblock);
1594

L
Linus Torvalds 已提交
1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606
	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
1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621
	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
1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644
	seq = &tp->copied_seq;
	if (flags & MSG_PEEK) {
		peek_seq = tp->copied_seq;
		seq = &peek_seq;
	}

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

	do {
		u32 offset;

		/* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
		if (tp->urg_data && tp->urg_seq == *seq) {
			if (copied)
				break;
			if (signal_pending(current)) {
				copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
				break;
			}
		}

		/* Next get a buffer. */

1645
		last = skb_peek_tail(&sk->sk_receive_queue);
1646
		skb_queue_walk(&sk->sk_receive_queue, skb) {
1647
			last = skb;
L
Linus Torvalds 已提交
1648 1649 1650
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1651
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1652 1653 1654
				 "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
1655
				break;
1656

L
Linus Torvalds 已提交
1657
			offset = *seq - TCP_SKB_CB(skb)->seq;
1658
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1659 1660 1661
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1662
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1663
				goto found_fin_ok;
J
Joe Perches 已提交
1664 1665 1666
			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);
1667
		}
L
Linus Torvalds 已提交
1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678

		/* 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 ||
1679
			    signal_pending(current))
L
Linus Torvalds 已提交
1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714
				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;
			}
		}

1715
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1716

1717
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1718 1719 1720 1721
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
1722
				tp->ucopy.msg = msg;
L
Linus Torvalds 已提交
1723 1724 1725 1726
			}

			tp->ucopy.len = len;

1727 1728
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755

			/* 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.
			 */
1756
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1757 1758 1759 1760 1761 1762 1763 1764 1765
				goto do_prequeue;

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

		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
1766 1767 1768
		} else {
			sk_wait_data(sk, &timeo, last);
		}
L
Linus Torvalds 已提交
1769 1770 1771 1772 1773 1774

		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

1775 1776
			chunk = len - tp->ucopy.len;
			if (chunk != 0) {
1777
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1778 1779 1780 1781 1782
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1783
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1784 1785 1786
do_prequeue:
				tcp_prequeue_process(sk);

1787 1788
				chunk = len - tp->ucopy.len;
				if (chunk != 0) {
1789
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1790 1791 1792 1793 1794
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1795 1796
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1797 1798 1799
			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
1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816
			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
1817
						urg_hole++;
L
Linus Torvalds 已提交
1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
1829
			err = skb_copy_datagram_msg(skb, offset, msg, used);
D
Dan Williams 已提交
1830 1831 1832 1833 1834
			if (err) {
				/* Exception. Bailout! */
				if (!copied)
					copied = -EFAULT;
				break;
L
Linus Torvalds 已提交
1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846
			}
		}

		*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;
1847
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1848 1849 1850 1851
		}
		if (used + offset < skb->len)
			continue;

1852
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1853
			goto found_fin_ok;
D
Dan Williams 已提交
1854 1855
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1856 1857 1858 1859 1860
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
D
Dan Williams 已提交
1861 1862
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1863 1864 1865 1866
		break;
	} while (len > 0);

	if (user_recv) {
1867
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1868 1869 1870 1871 1872 1873 1874
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1875
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889
				len -= chunk;
				copied += chunk;
			}
		}

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

	/* According to UNIX98, msg_name/msg_namelen are ignored
	 * on connected socket. I was just happy when found this 8) --ANK
	 */

	/* Clean up data we have read: This will do ACK frames. */
1890
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1891 1892 1893 1894 1895 1896 1897 1898 1899

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
1900
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1901
	goto out;
P
Pavel Emelyanov 已提交
1902 1903 1904 1905

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
1906
}
E
Eric Dumazet 已提交
1907
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
1908

I
Ilpo Järvinen 已提交
1909 1910 1911 1912 1913 1914 1915
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
1916
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1917 1918 1919 1920
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1921
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1922 1923 1924 1925

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1926
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1927 1928
		/* fall through */
	default:
1929
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1930
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1931 1932 1933 1934 1935 1936 1937 1938
	}

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

#ifdef STATE_TRACE
1939
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1940 1941 1942 1943
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1944 1945 1946 1947 1948 1949 1950
/*
 *	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.
 */

1951
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1952
  /* current state:        new state:      action:	*/
1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965
  [0 /* (Invalid) */]	= TCP_CLOSE,
  [TCP_ESTABLISHED]	= TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  [TCP_SYN_SENT]	= TCP_CLOSE,
  [TCP_SYN_RECV]	= TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  [TCP_FIN_WAIT1]	= TCP_FIN_WAIT1,
  [TCP_FIN_WAIT2]	= TCP_FIN_WAIT2,
  [TCP_TIME_WAIT]	= TCP_CLOSE,
  [TCP_CLOSE]		= TCP_CLOSE,
  [TCP_CLOSE_WAIT]	= TCP_LAST_ACK  | TCP_ACTION_FIN,
  [TCP_LAST_ACK]	= TCP_LAST_ACK,
  [TCP_LISTEN]		= TCP_CLOSE,
  [TCP_CLOSING]		= TCP_CLOSING,
  [TCP_NEW_SYN_RECV]	= TCP_CLOSE,	/* should not happen ! */
L
Linus Torvalds 已提交
1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979
};

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
1980
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
 */

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
2001
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
2002

A
Arun Sharma 已提交
2003 2004 2005 2006 2007 2008 2009
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);

2010 2011 2012 2013
	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
2014 2015 2016
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
2017 2018 2019 2020
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
2021
	int state;
L
Linus Torvalds 已提交
2022 2023 2024 2025 2026 2027 2028 2029

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

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

		/* Special case. */
2030
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2031 2032 2033 2034 2035 2036 2037 2038 2039

		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) {
2040 2041 2042 2043
		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
2044 2045 2046 2047
		data_was_unread += len;
		__kfree_skb(skb);
	}

2048
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2049

2050 2051 2052 2053
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2054 2055 2056 2057 2058 2059
	/* 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
2060
	 */
P
Pavel Emelyanov 已提交
2061 2062 2063
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2064
		/* Unread data was tossed, zap the connection. */
2065
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2066
		tcp_set_state(sk, TCP_CLOSE);
2067
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2068 2069 2070
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2071
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096
	} 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
2097 2098 2099 2100
		 * 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
2101 2102 2103 2104 2105 2106 2107
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2108 2109 2110 2111
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2112 2113 2114 2115 2116 2117 2118 2119 2120
	/* 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);
2121
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2122

H
Herbert Xu 已提交
2123 2124
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2125 2126 2127
	/* 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
2128 2129 2130 2131

	/*	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.
2132
	 *	We use a 1 minute timeout (about the same as BSD) then kill
L
Linus Torvalds 已提交
2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147
	 *	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);
2148 2149
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2150
		} else {
2151
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2152 2153

			if (tmo > TCP_TIMEWAIT_LEN) {
2154 2155
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2156 2157 2158 2159 2160 2161 2162
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2163
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2164
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2165 2166
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2167 2168
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2169 2170 2171
		}
	}

2172 2173 2174 2175 2176 2177
	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.
		 */
2178
		if (req)
2179
			reqsk_fastopen_remove(sk, req, false);
2180
		inet_csk_destroy_sock(sk);
2181
	}
L
Linus Torvalds 已提交
2182 2183 2184 2185 2186 2187 2188
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2189
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2190 2191 2192

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

E
Eric Dumazet 已提交
2193
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2194 2195 2196 2197 2198 2199 2200 2201 2202
{
	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);
2203
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2204 2205 2206 2207 2208 2209 2210 2211 2212
	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) {
2213
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2214 2215
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2216 2217 2218
	} 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
2219
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2220 2221 2222 2223 2224 2225 2226 2227 2228
		 * 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);
2229
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2230 2231
	__skb_queue_purge(&tp->out_of_order_queue);

E
Eric Dumazet 已提交
2232
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2233 2234 2235 2236 2237 2238

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

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
2239
	tp->srtt_us = 0;
2240 2241
	tp->write_seq += tp->max_window + 2;
	if (tp->write_seq == 0)
L
Linus Torvalds 已提交
2242
		tp->write_seq = 1;
2243
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2244
	tp->snd_cwnd = 2;
2245
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2246
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2247
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2248
	tp->snd_cwnd_cnt = 0;
2249
	tp->window_clamp = 0;
2250
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2251
	tcp_clear_retrans(tp);
2252
	inet_csk_delack_init(sk);
2253
	tcp_init_send_head(sk);
2254
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2255 2256
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2257
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2258 2259 2260 2261

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2262
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2263

E
Eric Dumazet 已提交
2264
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2265
{
2266
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2267 2268 2269
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2270 2271
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2272
{
2273
	struct tcp_repair_opt opt;
2274

2275 2276
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2277 2278 2279
			return -EFAULT;

		optbuf++;
2280
		len -= sizeof(opt);
2281

2282 2283 2284
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2285
			break;
2286
		case TCPOPT_WINDOW:
2287 2288 2289 2290 2291 2292
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2293

2294 2295 2296 2297
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2298 2299
			break;
		case TCPOPT_SACK_PERM:
2300 2301 2302
			if (opt.opt_val != 0)
				return -EINVAL;

2303 2304 2305 2306 2307
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2308 2309 2310
			if (opt.opt_val != 0)
				return -EINVAL;

2311 2312 2313 2314 2315 2316 2317 2318
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

L
Linus Torvalds 已提交
2319 2320 2321
/*
 *	Socket option code for TCP.
 */
2322
static int do_tcp_setsockopt(struct sock *sk, int level,
2323
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2324 2325
{
	struct tcp_sock *tp = tcp_sk(sk);
2326
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2327 2328 2329
	int val;
	int err = 0;

2330 2331 2332
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2333 2334 2335 2336 2337 2338
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2339
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2340 2341 2342 2343 2344
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2345
		err = tcp_set_congestion_control(sk, name);
2346 2347 2348
		release_sock(sk);
		return err;
	}
2349 2350 2351
	default:
		/* fallthru */
		break;
2352
	}
2353

L
Linus Torvalds 已提交
2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366
	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 */
2367
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384
			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;
2385
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2386 2387 2388 2389 2390
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2391 2392 2393 2394 2395 2396 2397
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2398 2399 2400
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
2401
		else {
A
Andreas Petlund 已提交
2402
			tp->thin_dupack = val;
Y
Yuchung Cheng 已提交
2403 2404
			if (tp->thin_dupack)
				tcp_disable_early_retrans(tp);
2405
		}
A
Andreas Petlund 已提交
2406 2407
		break;

P
Pavel Emelyanov 已提交
2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443
	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;

2444 2445 2446 2447
	case TCP_REPAIR_OPTIONS:
		if (!tp->repair)
			err = -EINVAL;
		else if (sk->sk_state == TCP_ESTABLISHED)
2448 2449 2450
			err = tcp_repair_options_est(tp,
					(struct tcp_repair_opt __user *)optval,
					optlen);
2451 2452 2453 2454
		else
			err = -EPERM;
		break;

L
Linus Torvalds 已提交
2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472
	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;
2473
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484
		}
		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))) {
2485
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2486 2487 2488 2489
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2490
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509
			}
		}
		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
2510
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2511 2512
		break;

2513 2514 2515 2516 2517 2518 2519
	case TCP_SAVE_SYN:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->save_syn = val;
		break;

L
Linus Torvalds 已提交
2520 2521 2522 2523 2524 2525 2526 2527 2528 2529
	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:
2530 2531 2532 2533
		/* 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
2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549
		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) {
2550
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2551
		} else {
2552
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2553 2554
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2555 2556
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2557
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2558
				if (!(val & 1))
2559
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2560 2561 2562 2563
			}
		}
		break;

2564 2565 2566 2567 2568 2569
#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
2570
	case TCP_USER_TIMEOUT:
2571
		/* Cap the max time in ms TCP will retry or probe the window
2572 2573
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2574 2575 2576 2577
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2578
		break;
2579 2580 2581

	case TCP_FASTOPEN:
		if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
2582 2583 2584
		    TCPF_LISTEN))) {
			tcp_fastopen_init_key_once(true);

2585
			fastopen_queue_tune(sk, val);
2586
		} else {
2587
			err = -EINVAL;
2588
		}
2589
		break;
2590 2591 2592 2593 2594 2595
	case TCP_TIMESTAMP:
		if (!tp->repair)
			err = -EPERM;
		else
			tp->tsoffset = val - tcp_time_stamp;
		break;
2596 2597 2598 2599
	case TCP_NOTSENT_LOWAT:
		tp->notsent_lowat = val;
		sk->sk_write_space(sk);
		break;
L
Linus Torvalds 已提交
2600 2601 2602
	default:
		err = -ENOPROTOOPT;
		break;
2603 2604
	}

L
Linus Torvalds 已提交
2605 2606 2607 2608
	release_sock(sk);
	return err;
}

2609
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2610
		   unsigned int optlen)
2611
{
2612
	const struct inet_connection_sock *icsk = inet_csk(sk);
2613 2614 2615 2616 2617 2618

	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
2619
EXPORT_SYMBOL(tcp_setsockopt);
2620 2621

#ifdef CONFIG_COMPAT
2622
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2623
			  char __user *optval, unsigned int optlen)
2624
{
2625 2626 2627
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2628 2629
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2630
EXPORT_SYMBOL(compat_tcp_setsockopt);
2631 2632
#endif

L
Linus Torvalds 已提交
2633
/* Return information about state of tcp endpoint in API format. */
2634
void tcp_get_info(struct sock *sk, struct tcp_info *info)
L
Linus Torvalds 已提交
2635
{
2636
	const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
2637
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2638
	u32 now = tcp_time_stamp;
2639
	unsigned int start;
2640
	u32 rate;
L
Linus Torvalds 已提交
2641 2642

	memset(info, 0, sizeof(*info));
2643 2644
	if (sk->sk_type != SOCK_STREAM)
		return;
L
Linus Torvalds 已提交
2645 2646

	info->tcpi_state = sk->sk_state;
2647
	info->tcpi_ca_state = icsk->icsk_ca_state;
2648
	info->tcpi_retransmits = icsk->icsk_retransmits;
2649
	info->tcpi_probes = icsk->icsk_probes_out;
2650
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2651 2652 2653

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2654
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2655 2656 2657 2658 2659
		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;
2660
	}
L
Linus Torvalds 已提交
2661

E
Eric Dumazet 已提交
2662
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2663
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2664 2665
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2666 2667
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2668

2669 2670
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2671
	info->tcpi_snd_mss = tp->mss_cache;
2672
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2673

2674 2675 2676 2677 2678 2679 2680
	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
2681 2682 2683 2684 2685
	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);
2686
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2687 2688
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2689
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2690
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2691 2692
	info->tcpi_rtt = tp->srtt_us >> 3;
	info->tcpi_rttvar = tp->mdev_us >> 2;
L
Linus Torvalds 已提交
2693 2694 2695 2696 2697 2698 2699 2700 2701
	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;
2702

2703 2704 2705 2706 2707
	rate = READ_ONCE(sk->sk_pacing_rate);
	info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL;

	rate = READ_ONCE(sk->sk_max_pacing_rate);
	info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL;
2708

2709 2710 2711 2712 2713
	do {
		start = u64_stats_fetch_begin_irq(&tp->syncp);
		info->tcpi_bytes_acked = tp->bytes_acked;
		info->tcpi_bytes_received = tp->bytes_received;
	} while (u64_stats_fetch_retry_irq(&tp->syncp, start));
2714 2715
	info->tcpi_segs_out = tp->segs_out;
	info->tcpi_segs_in = tp->segs_in;
L
Linus Torvalds 已提交
2716 2717 2718
}
EXPORT_SYMBOL_GPL(tcp_get_info);

2719 2720
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2721
{
2722
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735
	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:
2736
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2737 2738
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2739 2740
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2741 2742 2743 2744 2745 2746 2747 2748
		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
2749
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2750 2751
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2752
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2753 2754
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2755
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2756 2757
		break;
	case TCP_SYNCNT:
2758
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2759 2760 2761 2762 2763 2764 2765
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2766 2767
		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
2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786
		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;
	}
2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806
	case TCP_CC_INFO: {
		const struct tcp_congestion_ops *ca_ops;
		union tcp_cc_info info;
		size_t sz = 0;
		int attr;

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

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

		len = min_t(unsigned int, len, sz);
		if (put_user(len, optlen))
			return -EFAULT;
		if (copy_to_user(optval, &info, len))
			return -EFAULT;
		return 0;
	}
L
Linus Torvalds 已提交
2807
	case TCP_QUICKACK:
2808
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2809
		break;
2810 2811 2812 2813 2814 2815 2816

	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;
2817
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2818 2819
			return -EFAULT;
		return 0;
2820

2821 2822 2823 2824 2825 2826
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2827

P
Pavel Emelyanov 已提交
2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847
	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;

2848 2849 2850
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
2851 2852

	case TCP_FASTOPEN:
2853
		val = icsk->icsk_accept_queue.fastopenq.max_qlen;
2854 2855
		break;

2856 2857 2858
	case TCP_TIMESTAMP:
		val = tcp_time_stamp + tp->tsoffset;
		break;
2859 2860 2861
	case TCP_NOTSENT_LOWAT:
		val = tp->notsent_lowat;
		break;
2862 2863 2864 2865 2866 2867 2868 2869 2870
	case TCP_SAVE_SYN:
		val = tp->save_syn;
		break;
	case TCP_SAVED_SYN: {
		if (get_user(len, optlen))
			return -EFAULT;

		lock_sock(sk);
		if (tp->saved_syn) {
2871 2872 2873 2874 2875 2876 2877 2878 2879
			if (len < tp->saved_syn[0]) {
				if (put_user(tp->saved_syn[0], optlen)) {
					release_sock(sk);
					return -EFAULT;
				}
				release_sock(sk);
				return -EINVAL;
			}
			len = tp->saved_syn[0];
2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897
			if (put_user(len, optlen)) {
				release_sock(sk);
				return -EFAULT;
			}
			if (copy_to_user(optval, tp->saved_syn + 1, len)) {
				release_sock(sk);
				return -EFAULT;
			}
			tcp_saved_syn_free(tp);
			release_sock(sk);
		} else {
			release_sock(sk);
			len = 0;
			if (put_user(len, optlen))
				return -EFAULT;
		}
		return 0;
	}
L
Linus Torvalds 已提交
2898 2899
	default:
		return -ENOPROTOOPT;
2900
	}
L
Linus Torvalds 已提交
2901 2902 2903 2904 2905 2906 2907 2908

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

2909 2910 2911 2912 2913 2914 2915 2916 2917 2918
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
2919
EXPORT_SYMBOL(tcp_getsockopt);
2920 2921

#ifdef CONFIG_COMPAT
2922 2923
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2924
{
2925 2926 2927
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2928 2929
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2930
EXPORT_SYMBOL(compat_tcp_getsockopt);
2931
#endif
L
Linus Torvalds 已提交
2932

2933
#ifdef CONFIG_TCP_MD5SIG
E
Eric Dumazet 已提交
2934
static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2935
static DEFINE_MUTEX(tcp_md5sig_mutex);
E
Eric Dumazet 已提交
2936
static bool tcp_md5sig_pool_populated = false;
2937

2938
static void __tcp_alloc_md5sig_pool(void)
2939 2940 2941 2942
{
	int cpu;

	for_each_possible_cpu(cpu) {
E
Eric Dumazet 已提交
2943 2944
		if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
			struct crypto_hash *hash;
2945

E
Eric Dumazet 已提交
2946 2947 2948 2949 2950
			hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
			if (IS_ERR_OR_NULL(hash))
				return;
			per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm = hash;
		}
2951
	}
E
Eric Dumazet 已提交
2952 2953
	/* before setting tcp_md5sig_pool_populated, we must commit all writes
	 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2954 2955
	 */
	smp_wmb();
E
Eric Dumazet 已提交
2956
	tcp_md5sig_pool_populated = true;
2957 2958
}

2959
bool tcp_alloc_md5sig_pool(void)
2960
{
E
Eric Dumazet 已提交
2961
	if (unlikely(!tcp_md5sig_pool_populated)) {
2962 2963
		mutex_lock(&tcp_md5sig_mutex);

E
Eric Dumazet 已提交
2964
		if (!tcp_md5sig_pool_populated)
2965 2966 2967
			__tcp_alloc_md5sig_pool();

		mutex_unlock(&tcp_md5sig_mutex);
2968
	}
E
Eric Dumazet 已提交
2969
	return tcp_md5sig_pool_populated;
2970 2971 2972
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
2973 2974 2975 2976 2977 2978 2979 2980 2981

/**
 *	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)
2982
{
E
Eric Dumazet 已提交
2983
	local_bh_disable();
2984

E
Eric Dumazet 已提交
2985 2986 2987 2988 2989
	if (tcp_md5sig_pool_populated) {
		/* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
		smp_rmb();
		return this_cpu_ptr(&tcp_md5sig_pool);
	}
E
Eric Dumazet 已提交
2990 2991 2992 2993
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
2994

2995
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2996
			const struct tcphdr *th)
2997 2998
{
	struct scatterlist sg;
2999
	struct tcphdr hdr;
3000 3001
	int err;

3002 3003 3004 3005
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

3006
	/* options aren't included in the hash */
3007 3008
	sg_init_one(&sg, &hdr, sizeof(hdr));
	err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3009 3010 3011 3012 3013
	return err;
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3014
			  const struct sk_buff *skb, unsigned int header_len)
3015 3016 3017 3018
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
	struct hash_desc *desc = &hp->md5_desc;
3019 3020 3021
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
3022
	const struct skb_shared_info *shi = skb_shinfo(skb);
3023
	struct sk_buff *frag_iter;
3024 3025 3026 3027 3028 3029 3030 3031 3032

	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
3033 3034 3035 3036 3037
		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
3038
		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3039 3040 3041
			return 1;
	}

3042 3043 3044 3045
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3046 3047 3048 3049
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

3050
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3051 3052 3053 3054 3055 3056 3057 3058
{
	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);

3059 3060
#endif

A
Andi Kleen 已提交
3061 3062
void tcp_done(struct sock *sk)
{
3063 3064
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

3065
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3066
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3067 3068 3069

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
3070
	if (req)
3071
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
3072 3073 3074 3075 3076 3077 3078 3079 3080 3081

	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);

3082
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3083 3084 3085 3086

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
3087 3088
	ssize_t ret;

L
Linus Torvalds 已提交
3089 3090
	if (!str)
		return 0;
3091 3092 3093 3094 3095

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

L
Linus Torvalds 已提交
3096 3097 3098 3099
	return 1;
}
__setup("thash_entries=", set_thash_entries);

F
Fabian Frederick 已提交
3100
static void __init tcp_init_mem(void)
3101
{
E
Eric Dumazet 已提交
3102 3103
	unsigned long limit = nr_free_buffer_pages() / 16;

3104
	limit = max(limit, 128UL);
E
Eric Dumazet 已提交
3105 3106 3107
	sysctl_tcp_mem[0] = limit / 4 * 3;		/* 4.68 % */
	sysctl_tcp_mem[1] = limit;			/* 6.25 % */
	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;	/* 9.37 % */
3108 3109
}

L
Linus Torvalds 已提交
3110 3111
void __init tcp_init(void)
{
3112
	unsigned long limit;
3113
	int max_rshare, max_wshare, cnt;
3114
	unsigned int i;
L
Linus Torvalds 已提交
3115

3116
	sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
L
Linus Torvalds 已提交
3117

3118 3119
	percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
	percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3120 3121 3122
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3123
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3124 3125 3126 3127 3128 3129

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3130
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3131
		alloc_large_system_hash("TCP established",
3132
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3133
					thash_entries,
E
Eric Dumazet 已提交
3134
					17, /* one slot per 128 KB of memory */
3135
					0,
L
Linus Torvalds 已提交
3136
					NULL,
3137
					&tcp_hashinfo.ehash_mask,
3138
					0,
3139
					thash_entries ? 0 : 512 * 1024);
E
Eric Dumazet 已提交
3140
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3141
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
E
Eric Dumazet 已提交
3142

3143 3144
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3145
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3146
		alloc_large_system_hash("TCP bind",
3147
					sizeof(struct inet_bind_hashbucket),
3148
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3149
					17, /* one slot per 128 KB of memory */
3150
					0,
3151
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3152
					NULL,
3153
					0,
L
Linus Torvalds 已提交
3154
					64 * 1024);
3155
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3156 3157 3158
	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
3159 3160
	}

E
Eric Dumazet 已提交
3161 3162 3163 3164 3165 3166

	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
3167

3168
	tcp_init_mem();
3169
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3170
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3171 3172
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3173

3174
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3175
	sysctl_tcp_wmem[1] = 16*1024;
3176
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3177

3178
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3179
	sysctl_tcp_rmem[1] = 87380;
3180
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3181

3182
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3183
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3184

3185
	tcp_metrics_init();
3186
	BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
E
Eric Dumazet 已提交
3187
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3188
}