tcp.c 82.4 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();
529
				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;
L
Linus Torvalds 已提交
630 631
}

632
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
633
{
I
Ilpo Järvinen 已提交
634
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
635 636 637
		tp->snd_up = tp->write_seq;
}

E
Eric Dumazet 已提交
638
/* If a not yet filled skb is pushed, do not send it if
639
 * we have data packets in Qdisc or NIC queues :
E
Eric Dumazet 已提交
640 641 642 643
 * 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
644 645 646
 * 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
647 648 649
 */
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
				int size_goal)
L
Linus Torvalds 已提交
650
{
E
Eric Dumazet 已提交
651 652
	return skb->len < size_goal &&
	       sysctl_tcp_autocorking &&
653
	       skb != tcp_write_queue_head(sk) &&
E
Eric Dumazet 已提交
654 655 656 657 658 659 660 661
	       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;
662

E
Eric Dumazet 已提交
663 664
	if (!tcp_send_head(sk))
		return;
665

E
Eric Dumazet 已提交
666 667 668 669 670 671 672 673 674 675 676 677 678
	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);
		}
679 680 681 682 683
		/* 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
684
	}
E
Eric Dumazet 已提交
685 686 687 688 689

	if (flags & MSG_MORE)
		nonagle = TCP_NAGLE_CORK;

	__tcp_push_pending_frames(sk, mss_now, nonagle);
L
Linus Torvalds 已提交
690 691
}

692 693
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
694 695
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
696
	int ret;
J
Jens Axboe 已提交
697

698 699 700
	ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
			      min(rd_desc->count, len), tss->flags,
			      skb_socket_splice);
701 702 703
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
704 705 706 707 708 709 710
}

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,
711
		.count	  = tss->len,
J
Jens Axboe 已提交
712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742
	};

	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;

743
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
744 745 746 747 748 749 750 751 752 753
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

754
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792
	while (tss.len) {
		ret = __tcp_splice_read(sk, &tss);
		if (ret < 0)
			break;
		else if (!ret) {
			if (spliced)
				break;
			if (sock_flag(sk, SOCK_DONE))
				break;
			if (sk->sk_err) {
				ret = sock_error(sk);
				break;
			}
			if (sk->sk_shutdown & RCV_SHUTDOWN)
				break;
			if (sk->sk_state == TCP_CLOSE) {
				/*
				 * This occurs when user tries to read
				 * from never connected socket.
				 */
				if (!sock_flag(sk, SOCK_DONE))
					ret = -ENOTCONN;
				break;
			}
			if (!timeo) {
				ret = -EAGAIN;
				break;
			}
			sk_wait_data(sk, &timeo);
			if (signal_pending(current)) {
				ret = sock_intr_errno(timeo);
				break;
			}
			continue;
		}
		tss.len -= ret;
		spliced += ret;

793 794
		if (!timeo)
			break;
J
Jens Axboe 已提交
795 796 797 798
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
799
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
800 801 802 803 804 805 806 807 808 809 810
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
811
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
812

813 814
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
				    bool force_schedule)
815 816 817 818 819 820
{
	struct sk_buff *skb;

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

821 822 823
	if (unlikely(tcp_under_memory_pressure(sk)))
		sk_mem_reclaim_partial(sk);

824
	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
825
	if (likely(skb)) {
826
		bool mem_scheduled;
827

828 829
		if (force_schedule) {
			mem_scheduled = true;
830 831
			sk_forced_mem_schedule(sk, skb->truesize);
		} else {
832
			mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
833
		}
834
		if (likely(mem_scheduled)) {
835
			skb_reserve(skb, sk->sk_prot->max_header);
836 837 838 839
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
E
Eric Dumazet 已提交
840
			skb->reserved_tailroom = skb->end - skb->tail - size;
841 842 843 844
			return skb;
		}
		__kfree_skb(skb);
	} else {
845
		sk->sk_prot->enter_memory_pressure(sk);
846 847 848 849 850
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
851 852 853 854
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
855
	u32 new_size_goal, size_goal;
E
Eric Dumazet 已提交
856 857 858 859

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

860 861
	/* 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
862 863 864 865 866 867 868 869 870
	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
871 872
	}

E
Eric Dumazet 已提交
873
	return max(size_goal, mss_now);
I
Ilpo Järvinen 已提交
874 875 876 877 878 879 880 881 882 883 884 885
}

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;
}

886 887
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
888 889
{
	struct tcp_sock *tp = tcp_sk(sk);
890
	int mss_now, size_goal;
L
Linus Torvalds 已提交
891 892 893 894
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

895 896 897 898 899 900
	/* Wait for a connection to finish. One exception is TCP Fast Open
	 * (passive side) where data is allowed to be sent before a connection
	 * is fully established.
	 */
	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
	    !tcp_passive_fastopen(sk)) {
L
Linus Torvalds 已提交
901 902
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_err;
903
	}
L
Linus Torvalds 已提交
904 905 906

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

I
Ilpo Järvinen 已提交
907
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
908 909 910 911
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
912
		goto out_err;
L
Linus Torvalds 已提交
913

914
	while (size > 0) {
915
		struct sk_buff *skb = tcp_write_queue_tail(sk);
916 917
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
918

919
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
920 921 922 923
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

924 925
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
L
Linus Torvalds 已提交
926 927 928
			if (!skb)
				goto wait_for_memory;

929
			skb_entail(sk, skb);
930
			copy = size_goal;
L
Linus Torvalds 已提交
931 932 933 934 935 936 937 938 939 940 941
		}

		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;
		}
942
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
943
			goto wait_for_memory;
944

L
Linus Torvalds 已提交
945
		if (can_coalesce) {
E
Eric Dumazet 已提交
946
			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
947 948 949 950
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}
951
		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
952

L
Linus Torvalds 已提交
953 954 955 956
		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
957
		sk_mem_charge(sk, copy);
958
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
959 960
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
961
		tcp_skb_pcount_set(skb, 0);
L
Linus Torvalds 已提交
962 963

		if (!copied)
E
Eric Dumazet 已提交
964
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
965 966

		copied += copy;
967
		offset += copy;
968 969
		if (!(size -= copy)) {
			tcp_tx_timestamp(sk, skb);
L
Linus Torvalds 已提交
970
			goto out;
971
		}
L
Linus Torvalds 已提交
972

973
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
974 975 976 977
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
978
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
979
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
980 981 982 983 984 985
			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
986 987
		tcp_push(sk, flags & ~MSG_MORE, mss_now,
			 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
988 989 990 991

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

I
Ilpo Järvinen 已提交
992
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
993 994 995
	}

out:
996
	if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
E
Eric Dumazet 已提交
997
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
L
Linus Torvalds 已提交
998 999 1000 1001 1002 1003
	return copied;

do_error:
	if (copied)
		goto out;
out_err:
1004 1005 1006
	/* 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
1007 1008 1009
	return sk_stream_error(sk, flags, err);
}

1010 1011
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
1012 1013 1014 1015
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
1016
	    !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
1017 1018
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
1019 1020

	lock_sock(sk);
1021
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
1022 1023 1024
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
1025
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
1026

1027
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
1028
{
1029
	const struct tcp_sock *tp = tcp_sk(sk);
1030
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
1031

K
Krishna Kumar 已提交
1032
	if (sg) {
1033 1034 1035 1036 1037 1038
		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 {
1039 1040 1041 1042 1043 1044 1045
			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
1046 1047 1048 1049

	return tmp;
}

1050 1051
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
1052
	if (tp->fastopen_req) {
1053 1054 1055 1056 1057
		kfree(tp->fastopen_req);
		tp->fastopen_req = NULL;
	}
}

1058 1059
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
				int *copied, size_t size)
1060 1061 1062 1063 1064 1065
{
	struct tcp_sock *tp = tcp_sk(sk);
	int err, flags;

	if (!(sysctl_tcp_fastopen & TFO_CLIENT_ENABLE))
		return -EOPNOTSUPP;
1066
	if (tp->fastopen_req)
1067 1068 1069 1070
		return -EALREADY; /* Another Fast Open is in progress */

	tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
				   sk->sk_allocation);
1071
	if (unlikely(!tp->fastopen_req))
1072 1073
		return -ENOBUFS;
	tp->fastopen_req->data = msg;
1074
	tp->fastopen_req->size = size;
1075 1076 1077 1078

	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
	err = __inet_stream_connect(sk->sk_socket, msg->msg_name,
				    msg->msg_namelen, flags);
1079
	*copied = tp->fastopen_req->copied;
1080 1081 1082 1083
	tcp_free_fastopen_req(tp);
	return err;
}

1084
int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
L
Linus Torvalds 已提交
1085 1086 1087
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1088 1089
	int flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0;
1090
	bool sg;
L
Linus Torvalds 已提交
1091 1092 1093 1094 1095
	long timeo;

	lock_sock(sk);

	flags = msg->msg_flags;
1096
	if (flags & MSG_FASTOPEN) {
1097
		err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
1098 1099 1100 1101 1102 1103
		if (err == -EINPROGRESS && copied_syn > 0)
			goto out;
		else if (err)
			goto out_err;
	}

L
Linus Torvalds 已提交
1104 1105
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

1106 1107 1108 1109 1110 1111
	/* Wait for a connection to finish. One exception is TCP Fast Open
	 * (passive side) where data is allowed to be sent before a connection
	 * is fully established.
	 */
	if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
	    !tcp_passive_fastopen(sk)) {
L
Linus Torvalds 已提交
1112
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1113
			goto do_error;
1114
	}
L
Linus Torvalds 已提交
1115

P
Pavel Emelyanov 已提交
1116 1117 1118
	if (unlikely(tp->repair)) {
		if (tp->repair_queue == TCP_RECV_QUEUE) {
			copied = tcp_send_rcvq(sk, msg, size);
1119
			goto out_nopush;
P
Pavel Emelyanov 已提交
1120 1121 1122 1123 1124 1125 1126 1127 1128
		}

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

		/* 'common' sending to sendq */
	}

L
Linus Torvalds 已提交
1129 1130 1131
	/* This should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

I
Ilpo Järvinen 已提交
1132
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1133 1134 1135 1136 1137 1138

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

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1139
		goto out_err;
L
Linus Torvalds 已提交
1140

1141
	sg = !!(sk->sk_route_caps & NETIF_F_SG);
K
Krishna Kumar 已提交
1142

A
Al Viro 已提交
1143
	while (msg_data_left(msg)) {
1144 1145
		int copy = 0;
		int max = size_goal;
L
Linus Torvalds 已提交
1146

1147 1148 1149 1150 1151
		skb = tcp_write_queue_tail(sk);
		if (tcp_send_head(sk)) {
			if (skb->ip_summed == CHECKSUM_NONE)
				max = mss_now;
			copy = max - skb->len;
1152
		}
L
Linus Torvalds 已提交
1153

1154
		if (copy <= 0) {
L
Linus Torvalds 已提交
1155
new_segment:
1156 1157 1158 1159 1160
			/* 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
1161

1162 1163
			skb = sk_stream_alloc_skb(sk,
						  select_size(sk, sg),
1164 1165
						  sk->sk_allocation,
						  skb_queue_empty(&sk->sk_write_queue));
1166 1167
			if (!skb)
				goto wait_for_memory;
L
Linus Torvalds 已提交
1168

1169 1170 1171 1172 1173
			/*
			 * 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
1174

1175 1176 1177
			skb_entail(sk, skb);
			copy = size_goal;
			max = size_goal;
1178

1179 1180 1181 1182 1183 1184 1185
			/* 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
1186

1187
		/* Try to append data to the end of skb. */
A
Al Viro 已提交
1188 1189
		if (copy > msg_data_left(msg))
			copy = msg_data_left(msg);
1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204

		/* 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;
1205

1206 1207 1208 1209 1210
			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
1211
				}
1212
				merge = false;
L
Linus Torvalds 已提交
1213 1214
			}

1215 1216 1217 1218
			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
1219

1220 1221 1222 1223 1224 1225
			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
1226

1227 1228 1229 1230 1231 1232 1233
			/* 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);
1234
			}
1235 1236 1237 1238 1239 1240 1241 1242 1243
			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
1244

1245
		copied += copy;
A
Al Viro 已提交
1246
		if (!msg_data_left(msg)) {
1247 1248 1249
			tcp_tx_timestamp(sk, skb);
			goto out;
		}
L
Linus Torvalds 已提交
1250

1251
		if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1252 1253
			continue;

1254 1255 1256 1257 1258 1259 1260
		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
1261
wait_for_sndbuf:
1262
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
L
Linus Torvalds 已提交
1263
wait_for_memory:
1264 1265 1266
		if (copied)
			tcp_push(sk, flags & ~MSG_MORE, mss_now,
				 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
1267

1268 1269
		if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
			goto do_error;
L
Linus Torvalds 已提交
1270

1271
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1272 1273 1274
	}

out:
1275
	if (copied)
E
Eric Dumazet 已提交
1276
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
1277
out_nopush:
L
Linus Torvalds 已提交
1278
	release_sock(sk);
1279
	return copied + copied_syn;
L
Linus Torvalds 已提交
1280 1281 1282

do_fault:
	if (!skb->len) {
1283 1284 1285 1286 1287
		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);
1288
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1289 1290 1291
	}

do_error:
1292
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1293 1294 1295
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
1296 1297 1298
	/* 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
1299 1300 1301
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1302
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1303 1304 1305 1306 1307 1308

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

1309
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332
{
	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
1333
				err = memcpy_to_msg(msg, &c, 1);
L
Linus Torvalds 已提交
1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352
			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
1353 1354 1355 1356 1357 1358 1359 1360
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) {
1361
		err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
P
Pavel Emelyanov 已提交
1362 1363 1364 1365 1366 1367 1368 1369 1370
		if (err)
			break;

		copied += skb->len;
	}

	return err ?: copied;
}

L
Linus Torvalds 已提交
1371 1372 1373 1374 1375 1376
/* 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.
 */
1377
static void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1378 1379
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1380
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1381 1382 1383

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

1384
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1385
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1386
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1387

1388 1389
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1390 1391
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1392
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1393
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1394
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1395 1396 1397 1398 1399 1400
		    /*
		     * 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.
		     */
1401 1402 1403 1404 1405
		    (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
1406
			time_to_ack = true;
L
Linus Torvalds 已提交
1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427
	}

	/* 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
1428
				time_to_ack = true;
L
Linus Torvalds 已提交
1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439
		}
	}
	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);

1440
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1441 1442 1443 1444 1445

	/* 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
1446
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1447 1448 1449 1450 1451 1452
	local_bh_enable();

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

1453
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
L
Linus Torvalds 已提交
1454 1455 1456 1457
{
	struct sk_buff *skb;
	u32 offset;

1458
	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
L
Linus Torvalds 已提交
1459
		offset = seq - TCP_SKB_CB(skb)->seq;
1460
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1461
			offset--;
1462
		if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
L
Linus Torvalds 已提交
1463 1464 1465
			*off = offset;
			return skb;
		}
1466 1467 1468 1469
		/* 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
1470
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498
	}
	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) {
1499 1500
			int used;
			size_t len;
L
Linus Torvalds 已提交
1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511

			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);
1512
			if (used <= 0) {
1513 1514 1515 1516
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1517 1518 1519 1520
				seq += used;
				copied += used;
				offset += used;
			}
1521
			/* If recv_actor drops the lock (e.g. TCP splice
1522 1523 1524 1525
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1526 1527
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1528
				break;
1529 1530 1531 1532 1533
			/* 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
1534
		}
1535
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
D
Dan Williams 已提交
1536
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1537 1538 1539
			++seq;
			break;
		}
D
Dan Williams 已提交
1540
		sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1541 1542
		if (!desc->count)
			break;
1543
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1544 1545 1546 1547 1548 1549
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1550 1551
	if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
1552
		tcp_cleanup_rbuf(sk, copied);
1553
	}
L
Linus Torvalds 已提交
1554 1555
	return copied;
}
E
Eric Dumazet 已提交
1556
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1557 1558 1559 1560 1561 1562 1563 1564 1565

/*
 *	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.
 */

1566 1567
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
1568 1569 1570 1571 1572 1573 1574 1575 1576 1577
{
	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;
1578
	struct sk_buff *skb;
I
Ilpo Järvinen 已提交
1579
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1580

1581
	if (unlikely(flags & MSG_ERRQUEUE))
1582
		return inet_recv_error(sk, msg, len, addr_len);
1583

1584 1585 1586
	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
	    (sk->sk_state == TCP_ESTABLISHED))
		sk_busy_loop(sk, nonblock);
1587

L
Linus Torvalds 已提交
1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
	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
1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614
	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
1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637
	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. */

1638
		skb_queue_walk(&sk->sk_receive_queue, skb) {
L
Linus Torvalds 已提交
1639 1640 1641
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1642
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1643 1644 1645
				 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
				 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
				 flags))
L
Linus Torvalds 已提交
1646
				break;
1647

L
Linus Torvalds 已提交
1648
			offset = *seq - TCP_SKB_CB(skb)->seq;
1649
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
L
Linus Torvalds 已提交
1650 1651 1652
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1653
			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1654
				goto found_fin_ok;
J
Joe Perches 已提交
1655 1656 1657
			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);
1658
		}
L
Linus Torvalds 已提交
1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669

		/* 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 ||
1670
			    signal_pending(current))
L
Linus Torvalds 已提交
1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705
				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;
			}
		}

1706
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1707

1708
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1709 1710 1711 1712
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
1713
				tp->ucopy.msg = msg;
L
Linus Torvalds 已提交
1714 1715 1716 1717
			}

			tp->ucopy.len = len;

1718 1719
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746

			/* 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.
			 */
1747
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1748 1749 1750 1751 1752 1753 1754 1755 1756 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);
		} else
			sk_wait_data(sk, &timeo);

		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

			if ((chunk = len - tp->ucopy.len) != 0) {
1766
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1767 1768 1769 1770 1771
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1772
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1773 1774 1775 1776
do_prequeue:
				tcp_prequeue_process(sk);

				if ((chunk = len - tp->ucopy.len) != 0) {
1777
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1778 1779 1780 1781 1782
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1783 1784
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1785 1786 1787
			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
1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804
			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
1805
						urg_hole++;
L
Linus Torvalds 已提交
1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
1817
			err = skb_copy_datagram_msg(skb, offset, msg, used);
D
Dan Williams 已提交
1818 1819 1820 1821 1822
			if (err) {
				/* Exception. Bailout! */
				if (!copied)
					copied = -EFAULT;
				break;
L
Linus Torvalds 已提交
1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834
			}
		}

		*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;
1835
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1836 1837 1838 1839
		}
		if (used + offset < skb->len)
			continue;

1840
		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
L
Linus Torvalds 已提交
1841
			goto found_fin_ok;
D
Dan Williams 已提交
1842 1843
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1844 1845 1846 1847 1848
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
D
Dan Williams 已提交
1849 1850
		if (!(flags & MSG_PEEK))
			sk_eat_skb(sk, skb);
L
Linus Torvalds 已提交
1851 1852 1853 1854
		break;
	} while (len > 0);

	if (user_recv) {
1855
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1856 1857 1858 1859 1860 1861 1862
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1863
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877
				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. */
1878
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1879 1880 1881 1882 1883 1884 1885 1886 1887

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
1888
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1889
	goto out;
P
Pavel Emelyanov 已提交
1890 1891 1892 1893

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
1894
}
E
Eric Dumazet 已提交
1895
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
1896

I
Ilpo Järvinen 已提交
1897 1898 1899 1900 1901 1902 1903
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
1904
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1905 1906 1907 1908
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1909
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1910 1911 1912 1913

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1914
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1915 1916
		/* fall through */
	default:
1917
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1918
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1919 1920 1921 1922 1923 1924 1925 1926
	}

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

#ifdef STATE_TRACE
1927
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1928 1929 1930 1931
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1932 1933 1934 1935 1936 1937 1938
/*
 *	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.
 */

1939
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1940
  /* current state:        new state:      action:	*/
1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953
  [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
1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967
};

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
1968
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
 */

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
1989
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
1990

A
Arun Sharma 已提交
1991 1992 1993 1994 1995 1996 1997
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);

1998 1999 2000 2001
	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
2002 2003 2004
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
2005 2006 2007 2008
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
2009
	int state;
L
Linus Torvalds 已提交
2010 2011 2012 2013 2014 2015 2016 2017

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

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

		/* Special case. */
2018
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2019 2020 2021 2022 2023 2024 2025 2026 2027

		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) {
2028 2029 2030 2031
		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
2032 2033 2034 2035
		data_was_unread += len;
		__kfree_skb(skb);
	}

2036
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2037

2038 2039 2040 2041
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2042 2043 2044 2045 2046 2047
	/* 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
2048
	 */
P
Pavel Emelyanov 已提交
2049 2050 2051
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2052
		/* Unread data was tossed, zap the connection. */
2053
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2054
		tcp_set_state(sk, TCP_CLOSE);
2055
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2056 2057 2058
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2059
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084
	} 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
2085 2086 2087 2088
		 * 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
2089 2090 2091 2092 2093 2094 2095
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2096 2097 2098 2099
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2100 2101 2102 2103 2104 2105 2106 2107 2108
	/* 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);
2109
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2110

H
Herbert Xu 已提交
2111 2112
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2113 2114 2115
	/* 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
2116 2117 2118 2119

	/*	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.
2120
	 *	We use a 1 minute timeout (about the same as BSD) then kill
L
Linus Torvalds 已提交
2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135
	 *	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);
2136 2137
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2138
		} else {
2139
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2140 2141

			if (tmo > TCP_TIMEWAIT_LEN) {
2142 2143
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2144 2145 2146 2147 2148 2149 2150
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2151
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2152
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2153 2154
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2155 2156
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2157 2158 2159
		}
	}

2160 2161 2162 2163 2164 2165
	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.
		 */
2166
		if (req)
2167
			reqsk_fastopen_remove(sk, req, false);
2168
		inet_csk_destroy_sock(sk);
2169
	}
L
Linus Torvalds 已提交
2170 2171 2172 2173 2174 2175 2176
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2177
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2178 2179 2180

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

E
Eric Dumazet 已提交
2181
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2182 2183 2184 2185 2186 2187 2188 2189 2190
{
	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);
2191
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2192 2193 2194 2195 2196 2197 2198 2199 2200
	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) {
2201
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2202 2203
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2204 2205 2206
	} 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
2207
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2208 2209 2210 2211 2212 2213 2214 2215 2216
		 * 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);
2217
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2218 2219
	__skb_queue_purge(&tp->out_of_order_queue);

E
Eric Dumazet 已提交
2220
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2221 2222 2223 2224 2225 2226

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

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
2227
	tp->srtt_us = 0;
L
Linus Torvalds 已提交
2228 2229
	if ((tp->write_seq += tp->max_window + 2) == 0)
		tp->write_seq = 1;
2230
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2231
	tp->snd_cwnd = 2;
2232
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2233
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2234
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2235
	tp->snd_cwnd_cnt = 0;
2236
	tp->window_clamp = 0;
2237
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2238
	tcp_clear_retrans(tp);
2239
	inet_csk_delack_init(sk);
2240
	tcp_init_send_head(sk);
2241
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2242 2243
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2244
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2245 2246 2247 2248

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2249
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2250

2251 2252 2253 2254 2255 2256 2257
void tcp_sock_destruct(struct sock *sk)
{
	inet_sock_destruct(sk);

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

E
Eric Dumazet 已提交
2258
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2259
{
2260
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2261 2262 2263
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2264 2265
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2266
{
2267
	struct tcp_repair_opt opt;
2268

2269 2270
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2271 2272 2273
			return -EFAULT;

		optbuf++;
2274
		len -= sizeof(opt);
2275

2276 2277 2278
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2279
			break;
2280
		case TCPOPT_WINDOW:
2281 2282 2283 2284 2285 2286
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2287

2288 2289 2290 2291
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2292 2293
			break;
		case TCPOPT_SACK_PERM:
2294 2295 2296
			if (opt.opt_val != 0)
				return -EINVAL;

2297 2298 2299 2300 2301
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2302 2303 2304
			if (opt.opt_val != 0)
				return -EINVAL;

2305 2306 2307 2308 2309 2310 2311 2312
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

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

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

		if (optlen < 1)
			return -EINVAL;

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

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

L
Linus Torvalds 已提交
2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360
	if (optlen < sizeof(int))
		return -EINVAL;

	if (get_user(val, (int __user *)optval))
		return -EFAULT;

	lock_sock(sk);

	switch (optname) {
	case TCP_MAXSEG:
		/* Values greater than interface MTU won't take effect. However
		 * at the point when this call is done we typically don't yet
		 * know which interface is going to be used */
2361
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378
			err = -EINVAL;
			break;
		}
		tp->rx_opt.user_mss = val;
		break;

	case TCP_NODELAY:
		if (val) {
			/* TCP_NODELAY is weaker than TCP_CORK, so that
			 * this option on corked socket is remembered, but
			 * it is not activated until cork is cleared.
			 *
			 * However, when TCP_NODELAY is set we make
			 * an explicit push, which overrides even TCP_CORK
			 * for currently queued segments.
			 */
			tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
2379
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2380 2381 2382 2383 2384
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

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

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

P
Pavel Emelyanov 已提交
2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437
	case TCP_REPAIR:
		if (!tcp_can_repair_sock(sk))
			err = -EPERM;
		else if (val == 1) {
			tp->repair = 1;
			sk->sk_reuse = SK_FORCE_REUSE;
			tp->repair_queue = TCP_NO_QUEUE;
		} else if (val == 0) {
			tp->repair = 0;
			sk->sk_reuse = SK_NO_REUSE;
			tcp_send_window_probe(sk);
		} else
			err = -EINVAL;

		break;

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

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

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

L
Linus Torvalds 已提交
2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466
	case TCP_CORK:
		/* When set indicates to always queue non-full frames.
		 * Later the user clears this option and we transmit
		 * any pending partial frames in the queue.  This is
		 * meant to be used alongside sendfile() to get properly
		 * filled frames when the user (for example) must write
		 * out headers with a write() call first and then use
		 * sendfile to send out the data parts.
		 *
		 * TCP_CORK can be set together with TCP_NODELAY and it is
		 * stronger than TCP_NODELAY.
		 */
		if (val) {
			tp->nonagle |= TCP_NAGLE_CORK;
		} else {
			tp->nonagle &= ~TCP_NAGLE_CORK;
			if (tp->nonagle&TCP_NAGLE_OFF)
				tp->nonagle |= TCP_NAGLE_PUSH;
2467
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478
		}
		break;

	case TCP_KEEPIDLE:
		if (val < 1 || val > MAX_TCP_KEEPIDLE)
			err = -EINVAL;
		else {
			tp->keepalive_time = val * HZ;
			if (sock_flag(sk, SOCK_KEEPOPEN) &&
			    !((1 << sk->sk_state) &
			      (TCPF_CLOSE | TCPF_LISTEN))) {
2479
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2480 2481 2482 2483
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2484
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503
			}
		}
		break;
	case TCP_KEEPINTVL:
		if (val < 1 || val > MAX_TCP_KEEPINTVL)
			err = -EINVAL;
		else
			tp->keepalive_intvl = val * HZ;
		break;
	case TCP_KEEPCNT:
		if (val < 1 || val > MAX_TCP_KEEPCNT)
			err = -EINVAL;
		else
			tp->keepalive_probes = val;
		break;
	case TCP_SYNCNT:
		if (val < 1 || val > MAX_TCP_SYNCNT)
			err = -EINVAL;
		else
2504
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2505 2506
		break;

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

L
Linus Torvalds 已提交
2514 2515 2516 2517 2518 2519 2520 2521 2522 2523
	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:
2524 2525 2526 2527
		/* Translate value in seconds to number of retransmits */
		icsk->icsk_accept_queue.rskq_defer_accept =
			secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
					TCP_RTO_MAX / HZ);
L
Linus Torvalds 已提交
2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543
		break;

	case TCP_WINDOW_CLAMP:
		if (!val) {
			if (sk->sk_state != TCP_CLOSE) {
				err = -EINVAL;
				break;
			}
			tp->window_clamp = 0;
		} else
			tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
						SOCK_MIN_RCVBUF / 2 : val;
		break;

	case TCP_QUICKACK:
		if (!val) {
2544
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2545
		} else {
2546
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2547 2548
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2549 2550
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2551
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2552
				if (!(val & 1))
2553
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2554 2555 2556 2557
			}
		}
		break;

2558 2559 2560 2561 2562 2563
#ifdef CONFIG_TCP_MD5SIG
	case TCP_MD5SIG:
		/* Read the IP->Key mappings from userspace */
		err = tp->af_specific->md5_parse(sk, optval, optlen);
		break;
#endif
2564
	case TCP_USER_TIMEOUT:
2565
		/* Cap the max time in ms TCP will retry or probe the window
2566 2567
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2568 2569 2570 2571
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2572
		break;
2573 2574 2575

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

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

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

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

	if (level != SOL_TCP)
		return icsk->icsk_af_ops->setsockopt(sk, level, optname,
						     optval, optlen);
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
E
Eric Dumazet 已提交
2613
EXPORT_SYMBOL(tcp_setsockopt);
2614 2615

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

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

	memset(info, 0, sizeof(*info));
2637 2638
	if (sk->sk_type != SOCK_STREAM)
		return;
L
Linus Torvalds 已提交
2639 2640

	info->tcpi_state = sk->sk_state;
2641
	info->tcpi_ca_state = icsk->icsk_ca_state;
2642
	info->tcpi_retransmits = icsk->icsk_retransmits;
2643
	info->tcpi_probes = icsk->icsk_probes_out;
2644
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2645 2646 2647

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2648
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2649 2650 2651 2652 2653
		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;
2654
	}
L
Linus Torvalds 已提交
2655

E
Eric Dumazet 已提交
2656
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2657
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2658 2659
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2660 2661
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2662

2663 2664
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2665
	info->tcpi_snd_mss = tp->mss_cache;
2666
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2667

2668 2669 2670 2671 2672 2673 2674
	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
2675 2676 2677 2678 2679
	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);
2680
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2681 2682
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2683
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2684
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
2685 2686
	info->tcpi_rtt = tp->srtt_us >> 3;
	info->tcpi_rttvar = tp->mdev_us >> 2;
L
Linus Torvalds 已提交
2687 2688 2689 2690 2691 2692 2693 2694 2695
	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;
2696

2697 2698 2699 2700 2701
	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;
2702

2703 2704 2705 2706 2707
	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));
2708 2709
	info->tcpi_segs_out = tp->segs_out;
	info->tcpi_segs_in = tp->segs_in;
L
Linus Torvalds 已提交
2710 2711 2712
}
EXPORT_SYMBOL_GPL(tcp_get_info);

2713 2714
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2715
{
2716
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729
	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:
2730
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2731 2732
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2733 2734
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2735 2736 2737 2738 2739 2740 2741 2742
		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
2743
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2744 2745
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2746
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2747 2748
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2749
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2750 2751
		break;
	case TCP_SYNCNT:
2752
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2753 2754 2755 2756 2757 2758 2759
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2760 2761
		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
2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780
		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;
	}
2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800
	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
2801
	case TCP_QUICKACK:
2802
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2803
		break;
2804 2805 2806 2807 2808 2809 2810

	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;
2811
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2812 2813
			return -EFAULT;
		return 0;
2814

2815 2816 2817 2818 2819 2820
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2821

P
Pavel Emelyanov 已提交
2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841
	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;

2842 2843 2844
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
2845 2846

	case TCP_FASTOPEN:
2847
		if (icsk->icsk_accept_queue.fastopenq)
2848 2849 2850 2851 2852
			val = icsk->icsk_accept_queue.fastopenq->max_qlen;
		else
			val = 0;
		break;

2853 2854 2855
	case TCP_TIMESTAMP:
		val = tcp_time_stamp + tp->tsoffset;
		break;
2856 2857 2858
	case TCP_NOTSENT_LOWAT:
		val = tp->notsent_lowat;
		break;
2859 2860 2861 2862 2863 2864 2865 2866 2867
	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) {
2868 2869 2870 2871 2872 2873 2874 2875 2876
			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];
2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894
			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
2895 2896
	default:
		return -ENOPROTOOPT;
2897
	}
L
Linus Torvalds 已提交
2898 2899 2900 2901 2902 2903 2904 2905

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

2906 2907 2908 2909 2910 2911 2912 2913 2914 2915
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
2916
EXPORT_SYMBOL(tcp_getsockopt);
2917 2918

#ifdef CONFIG_COMPAT
2919 2920
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2921
{
2922 2923 2924
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2925 2926
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2927
EXPORT_SYMBOL(compat_tcp_getsockopt);
2928
#endif
L
Linus Torvalds 已提交
2929

2930
#ifdef CONFIG_TCP_MD5SIG
E
Eric Dumazet 已提交
2931
static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
2932
static DEFINE_MUTEX(tcp_md5sig_mutex);
E
Eric Dumazet 已提交
2933
static bool tcp_md5sig_pool_populated = false;
2934

2935
static void __tcp_alloc_md5sig_pool(void)
2936 2937 2938 2939
{
	int cpu;

	for_each_possible_cpu(cpu) {
E
Eric Dumazet 已提交
2940 2941
		if (!per_cpu(tcp_md5sig_pool, cpu).md5_desc.tfm) {
			struct crypto_hash *hash;
2942

E
Eric Dumazet 已提交
2943 2944 2945 2946 2947
			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;
		}
2948
	}
E
Eric Dumazet 已提交
2949 2950
	/* before setting tcp_md5sig_pool_populated, we must commit all writes
	 * to memory. See smp_rmb() in tcp_get_md5sig_pool()
2951 2952
	 */
	smp_wmb();
E
Eric Dumazet 已提交
2953
	tcp_md5sig_pool_populated = true;
2954 2955
}

2956
bool tcp_alloc_md5sig_pool(void)
2957
{
E
Eric Dumazet 已提交
2958
	if (unlikely(!tcp_md5sig_pool_populated)) {
2959 2960
		mutex_lock(&tcp_md5sig_mutex);

E
Eric Dumazet 已提交
2961
		if (!tcp_md5sig_pool_populated)
2962 2963 2964
			__tcp_alloc_md5sig_pool();

		mutex_unlock(&tcp_md5sig_mutex);
2965
	}
E
Eric Dumazet 已提交
2966
	return tcp_md5sig_pool_populated;
2967 2968 2969
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
2970 2971 2972 2973 2974 2975 2976 2977 2978

/**
 *	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)
2979
{
E
Eric Dumazet 已提交
2980
	local_bh_disable();
2981

E
Eric Dumazet 已提交
2982 2983 2984 2985 2986
	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
2987 2988 2989 2990
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
2991

2992
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
2993
			const struct tcphdr *th)
2994 2995
{
	struct scatterlist sg;
2996
	struct tcphdr hdr;
2997 2998
	int err;

2999 3000 3001 3002
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

3003
	/* options aren't included in the hash */
3004 3005
	sg_init_one(&sg, &hdr, sizeof(hdr));
	err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3006 3007 3008 3009 3010
	return err;
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3011
			  const struct sk_buff *skb, unsigned int header_len)
3012 3013 3014 3015
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
	struct hash_desc *desc = &hp->md5_desc;
3016 3017 3018
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
3019
	const struct skb_shared_info *shi = skb_shinfo(skb);
3020
	struct sk_buff *frag_iter;
3021 3022 3023 3024 3025 3026 3027 3028 3029

	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
3030 3031 3032 3033 3034
		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
3035
		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3036 3037 3038
			return 1;
	}

3039 3040 3041 3042
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3043 3044 3045 3046
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

3047
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3048 3049 3050 3051 3052 3053 3054 3055
{
	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);

3056 3057
#endif

A
Andi Kleen 已提交
3058 3059
void tcp_done(struct sock *sk)
{
3060 3061
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

3062
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3063
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3064 3065 3066

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
3067
	if (req)
3068
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
3069 3070 3071 3072 3073 3074 3075 3076 3077 3078

	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);

3079
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3080 3081 3082 3083

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
3084 3085
	ssize_t ret;

L
Linus Torvalds 已提交
3086 3087
	if (!str)
		return 0;
3088 3089 3090 3091 3092

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

L
Linus Torvalds 已提交
3093 3094 3095 3096
	return 1;
}
__setup("thash_entries=", set_thash_entries);

F
Fabian Frederick 已提交
3097
static void __init tcp_init_mem(void)
3098
{
E
Eric Dumazet 已提交
3099 3100
	unsigned long limit = nr_free_buffer_pages() / 16;

3101
	limit = max(limit, 128UL);
E
Eric Dumazet 已提交
3102 3103 3104
	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 % */
3105 3106
}

L
Linus Torvalds 已提交
3107 3108
void __init tcp_init(void)
{
3109
	unsigned long limit;
3110
	int max_rshare, max_wshare, cnt;
3111
	unsigned int i;
L
Linus Torvalds 已提交
3112

3113
	sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
L
Linus Torvalds 已提交
3114

3115 3116
	percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
	percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
3117 3118 3119
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3120
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3121 3122 3123 3124 3125 3126

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3127
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3128
		alloc_large_system_hash("TCP established",
3129
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3130
					thash_entries,
E
Eric Dumazet 已提交
3131
					17, /* one slot per 128 KB of memory */
3132
					0,
L
Linus Torvalds 已提交
3133
					NULL,
3134
					&tcp_hashinfo.ehash_mask,
3135
					0,
3136
					thash_entries ? 0 : 512 * 1024);
E
Eric Dumazet 已提交
3137
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3138
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
E
Eric Dumazet 已提交
3139

3140 3141
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3142
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3143
		alloc_large_system_hash("TCP bind",
3144
					sizeof(struct inet_bind_hashbucket),
3145
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3146
					17, /* one slot per 128 KB of memory */
3147
					0,
3148
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3149
					NULL,
3150
					0,
L
Linus Torvalds 已提交
3151
					64 * 1024);
3152
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3153 3154 3155
	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
3156 3157
	}

E
Eric Dumazet 已提交
3158 3159 3160 3161 3162 3163

	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
3164

3165
	tcp_init_mem();
3166
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3167
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3168 3169
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3170

3171
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3172
	sysctl_tcp_wmem[1] = 16*1024;
3173
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3174

3175
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3176
	sysctl_tcp_rmem[1] = 87380;
3177
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3178

3179
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3180
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3181

3182
	tcp_metrics_init();
3183
	BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
E
Eric Dumazet 已提交
3184
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3185
}