tcp.c 82.9 KB
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/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Implementation of the Transmission Control Protocol(TCP).
 *
8
 * Authors:	Ross Biro
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 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Mark Evans, <evansmp@uhura.aston.ac.uk>
 *		Corey Minyard <wf-rch!minyard@relay.EU.net>
 *		Florian La Roche, <flla@stud.uni-sb.de>
 *		Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
 *		Linus Torvalds, <torvalds@cs.helsinki.fi>
 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 *		Matthew Dillon, <dillon@apollo.west.oic.com>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *		Jorge Cwik, <jorge@laser.satlink.net>
 *
 * Fixes:
 *		Alan Cox	:	Numerous verify_area() calls
 *		Alan Cox	:	Set the ACK bit on a reset
 *		Alan Cox	:	Stopped it crashing if it closed while
 *					sk->inuse=1 and was trying to connect
 *					(tcp_err()).
 *		Alan Cox	:	All icmp error handling was broken
 *					pointers passed where wrong and the
 *					socket was looked up backwards. Nobody
 *					tested any icmp error code obviously.
 *		Alan Cox	:	tcp_err() now handled properly. It
 *					wakes people on errors. poll
 *					behaves and the icmp error race
 *					has gone by moving it into sock.c
 *		Alan Cox	:	tcp_send_reset() fixed to work for
 *					everything not just packets for
 *					unknown sockets.
 *		Alan Cox	:	tcp option processing.
 *		Alan Cox	:	Reset tweaked (still not 100%) [Had
 *					syn rule wrong]
 *		Herp Rosmanith  :	More reset fixes
 *		Alan Cox	:	No longer acks invalid rst frames.
 *					Acking any kind of RST is right out.
 *		Alan Cox	:	Sets an ignore me flag on an rst
 *					receive otherwise odd bits of prattle
 *					escape still
 *		Alan Cox	:	Fixed another acking RST frame bug.
 *					Should stop LAN workplace lockups.
 *		Alan Cox	: 	Some tidyups using the new skb list
 *					facilities
 *		Alan Cox	:	sk->keepopen now seems to work
 *		Alan Cox	:	Pulls options out correctly on accepts
 *		Alan Cox	:	Fixed assorted sk->rqueue->next errors
 *		Alan Cox	:	PSH doesn't end a TCP read. Switched a
 *					bit to skb ops.
 *		Alan Cox	:	Tidied tcp_data to avoid a potential
 *					nasty.
 *		Alan Cox	:	Added some better commenting, as the
 *					tcp is hard to follow
 *		Alan Cox	:	Removed incorrect check for 20 * psh
 *	Michael O'Reilly	:	ack < copied bug fix.
 *	Johannes Stille		:	Misc tcp fixes (not all in yet).
 *		Alan Cox	:	FIN with no memory -> CRASH
 *		Alan Cox	:	Added socket option proto entries.
 *					Also added awareness of them to accept.
 *		Alan Cox	:	Added TCP options (SOL_TCP)
 *		Alan Cox	:	Switched wakeup calls to callbacks,
 *					so the kernel can layer network
 *					sockets.
 *		Alan Cox	:	Use ip_tos/ip_ttl settings.
 *		Alan Cox	:	Handle FIN (more) properly (we hope).
 *		Alan Cox	:	RST frames sent on unsynchronised
 *					state ack error.
 *		Alan Cox	:	Put in missing check for SYN bit.
 *		Alan Cox	:	Added tcp_select_window() aka NET2E
 *					window non shrink trick.
 *		Alan Cox	:	Added a couple of small NET2E timer
 *					fixes
 *		Charles Hedrick :	TCP fixes
 *		Toomas Tamm	:	TCP window fixes
 *		Alan Cox	:	Small URG fix to rlogin ^C ack fight
 *		Charles Hedrick	:	Rewrote most of it to actually work
 *		Linus		:	Rewrote tcp_read() and URG handling
 *					completely
 *		Gerhard Koerting:	Fixed some missing timer handling
 *		Matthew Dillon  :	Reworked TCP machine states as per RFC
 *		Gerhard Koerting:	PC/TCP workarounds
 *		Adam Caldwell	:	Assorted timer/timing errors
 *		Matthew Dillon	:	Fixed another RST bug
 *		Alan Cox	:	Move to kernel side addressing changes.
 *		Alan Cox	:	Beginning work on TCP fastpathing
 *					(not yet usable)
 *		Arnt Gulbrandsen:	Turbocharged tcp_check() routine.
 *		Alan Cox	:	TCP fast path debugging
 *		Alan Cox	:	Window clamping
 *		Michael Riepe	:	Bug in tcp_check()
 *		Matt Dillon	:	More TCP improvements and RST bug fixes
 *		Matt Dillon	:	Yet more small nasties remove from the
 *					TCP code (Be very nice to this man if
 *					tcp finally works 100%) 8)
 *		Alan Cox	:	BSD accept semantics.
 *		Alan Cox	:	Reset on closedown bug.
 *	Peter De Schrijver	:	ENOTCONN check missing in tcp_sendto().
 *		Michael Pall	:	Handle poll() after URG properly in
 *					all cases.
 *		Michael Pall	:	Undo the last fix in tcp_read_urg()
 *					(multi URG PUSH broke rlogin).
 *		Michael Pall	:	Fix the multi URG PUSH problem in
 *					tcp_readable(), poll() after URG
 *					works now.
 *		Michael Pall	:	recv(...,MSG_OOB) never blocks in the
 *					BSD api.
 *		Alan Cox	:	Changed the semantics of sk->socket to
 *					fix a race and a signal problem with
 *					accept() and async I/O.
 *		Alan Cox	:	Relaxed the rules on tcp_sendto().
 *		Yury Shevchuk	:	Really fixed accept() blocking problem.
 *		Craig I. Hagan  :	Allow for BSD compatible TIME_WAIT for
 *					clients/servers which listen in on
 *					fixed ports.
 *		Alan Cox	:	Cleaned the above up and shrank it to
 *					a sensible code size.
 *		Alan Cox	:	Self connect lockup fix.
 *		Alan Cox	:	No connect to multicast.
 *		Ross Biro	:	Close unaccepted children on master
 *					socket close.
 *		Alan Cox	:	Reset tracing code.
 *		Alan Cox	:	Spurious resets on shutdown.
 *		Alan Cox	:	Giant 15 minute/60 second timer error
 *		Alan Cox	:	Small whoops in polling before an
 *					accept.
 *		Alan Cox	:	Kept the state trace facility since
 *					it's handy for debugging.
 *		Alan Cox	:	More reset handler fixes.
 *		Alan Cox	:	Started rewriting the code based on
 *					the RFC's for other useful protocol
 *					references see: Comer, KA9Q NOS, and
 *					for a reference on the difference
 *					between specifications and how BSD
 *					works see the 4.4lite source.
 *		A.N.Kuznetsov	:	Don't time wait on completion of tidy
 *					close.
 *		Linus Torvalds	:	Fin/Shutdown & copied_seq changes.
 *		Linus Torvalds	:	Fixed BSD port reuse to work first syn
 *		Alan Cox	:	Reimplemented timers as per the RFC
 *					and using multiple timers for sanity.
 *		Alan Cox	:	Small bug fixes, and a lot of new
 *					comments.
 *		Alan Cox	:	Fixed dual reader crash by locking
 *					the buffers (much like datagram.c)
 *		Alan Cox	:	Fixed stuck sockets in probe. A probe
 *					now gets fed up of retrying without
 *					(even a no space) answer.
 *		Alan Cox	:	Extracted closing code better
 *		Alan Cox	:	Fixed the closing state machine to
 *					resemble the RFC.
 *		Alan Cox	:	More 'per spec' fixes.
 *		Jorge Cwik	:	Even faster checksumming.
 *		Alan Cox	:	tcp_data() doesn't ack illegal PSH
 *					only frames. At least one pc tcp stack
 *					generates them.
 *		Alan Cox	:	Cache last socket.
 *		Alan Cox	:	Per route irtt.
 *		Matt Day	:	poll()->select() match BSD precisely on error
 *		Alan Cox	:	New buffers
 *		Marc Tamsky	:	Various sk->prot->retransmits and
 *					sk->retransmits misupdating fixed.
 *					Fixed tcp_write_timeout: stuck close,
 *					and TCP syn retries gets used now.
 *		Mark Yarvis	:	In tcp_read_wakeup(), don't send an
 *					ack if state is TCP_CLOSED.
 *		Alan Cox	:	Look up device on a retransmit - routes may
 *					change. Doesn't yet cope with MSS shrink right
 *					but it's a start!
 *		Marc Tamsky	:	Closing in closing fixes.
 *		Mike Shaver	:	RFC1122 verifications.
 *		Alan Cox	:	rcv_saddr errors.
 *		Alan Cox	:	Block double connect().
 *		Alan Cox	:	Small hooks for enSKIP.
 *		Alexey Kuznetsov:	Path MTU discovery.
 *		Alan Cox	:	Support soft errors.
 *		Alan Cox	:	Fix MTU discovery pathological case
 *					when the remote claims no mtu!
 *		Marc Tamsky	:	TCP_CLOSE fix.
 *		Colin (G3TNE)	:	Send a reset on syn ack replies in
 *					window but wrong (fixes NT lpd problems)
 *		Pedro Roque	:	Better TCP window handling, delayed ack.
 *		Joerg Reuter	:	No modification of locked buffers in
 *					tcp_do_retransmit()
 *		Eric Schenk	:	Changed receiver side silly window
 *					avoidance algorithm to BSD style
 *					algorithm. This doubles throughput
 *					against machines running Solaris,
 *					and seems to result in general
 *					improvement.
 *	Stefan Magdalinski	:	adjusted tcp_readable() to fix FIONREAD
 *	Willy Konynenberg	:	Transparent proxying support.
 *	Mike McLagan		:	Routing by source
 *		Keith Owens	:	Do proper merging with partial SKB's in
 *					tcp_do_sendmsg to avoid burstiness.
 *		Eric Schenk	:	Fix fast close down bug with
 *					shutdown() followed by close().
 *		Andi Kleen 	:	Make poll agree with SIGIO
 *	Salvatore Sanfilippo	:	Support SO_LINGER with linger == 1 and
 *					lingertime == 0 (RFC 793 ABORT Call)
 *	Hirokazu Takahashi	:	Use copy_from_user() instead of
 *					csum_and_copy_from_user() if possible.
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or(at your option) any later version.
 *
 * Description of States:
 *
 *	TCP_SYN_SENT		sent a connection request, waiting for ack
 *
 *	TCP_SYN_RECV		received a connection request, sent ack,
 *				waiting for final ack in three-way handshake.
 *
 *	TCP_ESTABLISHED		connection established
 *
 *	TCP_FIN_WAIT1		our side has shutdown, waiting to complete
 *				transmission of remaining buffered data
 *
 *	TCP_FIN_WAIT2		all buffered data sent, waiting for remote
 *				to shutdown
 *
 *	TCP_CLOSING		both sides have shutdown but we still have
 *				data we have to finish sending
 *
 *	TCP_TIME_WAIT		timeout to catch resent junk before entering
 *				closed, can only be entered from FIN_WAIT2
 *				or CLOSING.  Required because the other end
 *				may not have gotten our last ACK causing it
 *				to retransmit the data packet (which we ignore)
 *
 *	TCP_CLOSE_WAIT		remote side has shutdown and is waiting for
 *				us to finish writing our data and to shutdown
 *				(we have to close() to move on to LAST_ACK)
 *
 *	TCP_LAST_ACK		out side has shutdown after remote has
 *				shutdown.  There may still be data in our
 *				buffer that we have to finish sending
 *
 *	TCP_CLOSE		socket is finished
 */

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#define pr_fmt(fmt) "TCP: " fmt

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

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int sysctl_tcp_autocorking __read_mostly = 1;

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struct percpu_counter tcp_orphan_count;
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EXPORT_SYMBOL_GPL(tcp_orphan_count);

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

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

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

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

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

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

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

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

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

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

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

	skb_queue_head_init(&tp->out_of_order_queue);
	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;
	tp->mdev = TCP_TIMEOUT_INIT;

	/* So many TCP implementations out there (incorrectly) count the
	 * initial SYN frame in their delayed-ACK and congestion control
	 * algorithms that we must have the following bandaid to talk
	 * efficiently to them.  -DaveM
	 */
	tp->snd_cwnd = TCP_INIT_CWND;

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

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

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	tp->tsoffset = 0;

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	sk->sk_state = TCP_CLOSE;

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

	icsk->icsk_sync_mss = tcp_sync_mss;

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

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

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

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

	mask = 0;

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

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

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

				/* Race breaker. If space is freed after
				 * wspace test but before the flags are set,
				 * IO signal will be lost.
				 */
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				if (sk_stream_is_writeable(sk))
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					mask |= POLLOUT | POLLWRNORM;
			}
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		} else
			mask |= POLLOUT | POLLWRNORM;
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		if (tp->urg_data & TCP_URG_VALID)
			mask |= POLLPRI;
	}
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	/* This barrier is coupled with smp_wmb() in tcp_reset() */
	smp_rmb();
	if (sk->sk_err)
		mask |= POLLERR;

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	return mask;
}
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EXPORT_SYMBOL(tcp_poll);
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Linus Torvalds 已提交
532 533 534 535 536

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
537
	bool slow;
L
Linus Torvalds 已提交
538 539 540 541 542 543

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

E
Eric Dumazet 已提交
544
		slow = lock_sock_fast(sk);
L
Linus Torvalds 已提交
545 546 547 548 549 550
		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)) {
551

L
Linus Torvalds 已提交
552 553
			answ = tp->rcv_nxt - tp->copied_seq;

E
Eric Dumazet 已提交
554 555 556
			/* Subtract 1, if FIN was received */
			if (answ && sock_flag(sk, SOCK_DONE))
				answ--;
L
Linus Torvalds 已提交
557 558
		} else
			answ = tp->urg_seq - tp->copied_seq;
E
Eric Dumazet 已提交
559
		unlock_sock_fast(sk, slow);
L
Linus Torvalds 已提交
560 561 562 563 564 565 566 567 568 569 570 571 572
		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;
573 574 575 576 577 578 579 580 581
	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
582 583
	default:
		return -ENOIOCTLCMD;
584
	}
L
Linus Torvalds 已提交
585 586 587

	return put_user(answ, (int __user *)arg);
}
E
Eric Dumazet 已提交
588
EXPORT_SYMBOL(tcp_ioctl);
L
Linus Torvalds 已提交
589 590 591

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
592
	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
L
Linus Torvalds 已提交
593 594 595
	tp->pushed_seq = tp->write_seq;
}

E
Eric Dumazet 已提交
596
static inline bool forced_push(const struct tcp_sock *tp)
L
Linus Torvalds 已提交
597 598 599 600
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

601
static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
602
{
603
	struct tcp_sock *tp = tcp_sk(sk);
604 605 606 607
	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
608
	tcb->tcp_flags = TCPHDR_ACK;
609
	tcb->sacked  = 0;
L
Linus Torvalds 已提交
610
	skb_header_release(skb);
611
	tcp_add_write_queue_tail(sk, skb);
612 613
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
614
	if (tp->nonagle & TCP_NAGLE_PUSH)
615
		tp->nonagle &= ~TCP_NAGLE_PUSH;
L
Linus Torvalds 已提交
616 617
}

618
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
619
{
I
Ilpo Järvinen 已提交
620
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
621 622 623
		tp->snd_up = tp->write_seq;
}

E
Eric Dumazet 已提交
624
/* If a not yet filled skb is pushed, do not send it if
625
 * we have data packets in Qdisc or NIC queues :
E
Eric Dumazet 已提交
626 627 628 629
 * 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
630 631 632
 * 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
633 634 635
 */
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
				int size_goal)
L
Linus Torvalds 已提交
636
{
E
Eric Dumazet 已提交
637 638
	return skb->len < size_goal &&
	       sysctl_tcp_autocorking &&
639
	       skb != tcp_write_queue_head(sk) &&
E
Eric Dumazet 已提交
640 641 642 643 644 645 646 647
	       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;
648

E
Eric Dumazet 已提交
649 650
	if (!tcp_send_head(sk))
		return;
651

E
Eric Dumazet 已提交
652 653 654 655 656 657 658 659 660 661 662 663 664
	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);
		}
665 666 667 668 669
		/* 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
670
	}
E
Eric Dumazet 已提交
671 672 673 674 675

	if (flags & MSG_MORE)
		nonagle = TCP_NAGLE_CORK;

	__tcp_push_pending_frames(sk, mss_now, nonagle);
L
Linus Torvalds 已提交
676 677
}

678 679
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
680 681
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
682
	int ret;
J
Jens Axboe 已提交
683

684 685
	ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
			      tss->flags);
686 687 688
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
689 690 691 692 693 694 695
}

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,
696
		.count	  = tss->len,
J
Jens Axboe 已提交
697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
	};

	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;

728
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
729 730 731 732 733 734 735 736 737 738
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

739
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777
	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;

778 779
		if (!timeo)
			break;
J
Jens Axboe 已提交
780 781 782 783
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
784
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
785 786 787 788 789 790 791 792 793 794 795
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
796
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
797

798
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
799 800 801 802 803 804 805 806
{
	struct sk_buff *skb;

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

	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
	if (skb) {
807
		if (sk_wmem_schedule(sk, skb->truesize)) {
808
			skb_reserve(skb, sk->sk_prot->max_header);
809 810 811 812
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
E
Eric Dumazet 已提交
813
			skb->reserved_tailroom = skb->end - skb->tail - size;
814 815 816 817
			return skb;
		}
		__kfree_skb(skb);
	} else {
818
		sk->sk_prot->enter_memory_pressure(sk);
819 820 821 822 823
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
824 825 826 827
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
828
	u32 xmit_size_goal, old_size_goal;
I
Ilpo Järvinen 已提交
829 830 831 832

	xmit_size_goal = mss_now;

	if (large_allowed && sk_can_gso(sk)) {
E
Eric Dumazet 已提交
833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851
		u32 gso_size, hlen;

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

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

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

I
Ilpo Järvinen 已提交
852
		xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
853 854 855 856 857 858 859 860

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

		if (likely(old_size_goal <= xmit_size_goal &&
			   old_size_goal + mss_now > xmit_size_goal)) {
			xmit_size_goal = old_size_goal;
		} else {
861 862 863
			tp->xmit_size_goal_segs =
				min_t(u16, xmit_size_goal / mss_now,
				      sk->sk_gso_max_segs);
864 865
			xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
		}
I
Ilpo Järvinen 已提交
866 867
	}

868
	return max(xmit_size_goal, mss_now);
I
Ilpo Järvinen 已提交
869 870 871 872 873 874 875 876 877 878 879 880
}

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;
}

881 882
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
883 884
{
	struct tcp_sock *tp = tcp_sk(sk);
885
	int mss_now, size_goal;
L
Linus Torvalds 已提交
886 887 888 889
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

890 891 892 893 894 895
	/* 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
896 897
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_err;
898
	}
L
Linus Torvalds 已提交
899 900 901

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

I
Ilpo Järvinen 已提交
902
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
903 904 905 906
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
907
		goto out_err;
L
Linus Torvalds 已提交
908

909
	while (size > 0) {
910
		struct sk_buff *skb = tcp_write_queue_tail(sk);
911 912
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
913

914
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
915 916 917 918
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

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

923
			skb_entail(sk, skb);
924
			copy = size_goal;
L
Linus Torvalds 已提交
925 926 927 928 929 930 931 932 933 934 935
		}

		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;
		}
936
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
937
			goto wait_for_memory;
938

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

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

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

		copied += copy;
961 962
		offset += copy;
		if (!(size -= copy))
L
Linus Torvalds 已提交
963 964
			goto out;

965
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
966 967 968 969
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
970
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
971
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
972 973 974 975 976 977
			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
978 979
		tcp_push(sk, flags & ~MSG_MORE, mss_now,
			 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
980 981 982 983

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

I
Ilpo Järvinen 已提交
984
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
985 986 987
	}

out:
988
	if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
E
Eric Dumazet 已提交
989
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
L
Linus Torvalds 已提交
990 991 992 993 994 995 996 997 998
	return copied;

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

999 1000
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
1001 1002 1003 1004
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
1005
	    !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
1006 1007
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
1008 1009

	lock_sock(sk);
1010
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
1011 1012 1013
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
1014
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
1015

1016
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
1017
{
1018
	const struct tcp_sock *tp = tcp_sk(sk);
1019
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
1020

K
Krishna Kumar 已提交
1021
	if (sg) {
1022 1023 1024 1025 1026 1027
		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 {
1028 1029 1030 1031 1032 1033 1034
			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
1035 1036 1037 1038

	return tmp;
}

1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
	if (tp->fastopen_req != NULL) {
		kfree(tp->fastopen_req);
		tp->fastopen_req = NULL;
	}
}

static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *size)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int err, flags;

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

	tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
				   sk->sk_allocation);
	if (unlikely(tp->fastopen_req == NULL))
		return -ENOBUFS;
	tp->fastopen_req->data = msg;

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

1071
int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
L
Linus Torvalds 已提交
1072 1073 1074 1075 1076
		size_t size)
{
	struct iovec *iov;
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1077 1078
	int iovlen, flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
1079
	bool sg;
L
Linus Torvalds 已提交
1080 1081 1082 1083 1084
	long timeo;

	lock_sock(sk);

	flags = msg->msg_flags;
1085 1086 1087 1088 1089 1090 1091 1092 1093
	if (flags & MSG_FASTOPEN) {
		err = tcp_sendmsg_fastopen(sk, msg, &copied_syn);
		if (err == -EINPROGRESS && copied_syn > 0)
			goto out;
		else if (err)
			goto out_err;
		offset = copied_syn;
	}

L
Linus Torvalds 已提交
1094 1095
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

1096 1097 1098 1099 1100 1101
	/* 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
1102
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1103
			goto do_error;
1104
	}
L
Linus Torvalds 已提交
1105

P
Pavel Emelyanov 已提交
1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118
	if (unlikely(tp->repair)) {
		if (tp->repair_queue == TCP_RECV_QUEUE) {
			copied = tcp_send_rcvq(sk, msg, size);
			goto out;
		}

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

		/* 'common' sending to sendq */
	}

L
Linus Torvalds 已提交
1119 1120 1121
	/* This should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

I
Ilpo Järvinen 已提交
1122
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1123 1124 1125 1126 1127 1128 1129 1130

	/* Ok commence sending. */
	iovlen = msg->msg_iovlen;
	iov = msg->msg_iov;
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1131
		goto out_err;
L
Linus Torvalds 已提交
1132

1133
	sg = !!(sk->sk_route_caps & NETIF_F_SG);
K
Krishna Kumar 已提交
1134

L
Linus Torvalds 已提交
1135
	while (--iovlen >= 0) {
1136
		size_t seglen = iov->iov_len;
L
Linus Torvalds 已提交
1137 1138 1139
		unsigned char __user *from = iov->iov_base;

		iov++;
1140 1141 1142 1143 1144 1145 1146 1147 1148
		if (unlikely(offset > 0)) {  /* Skip bytes copied in SYN */
			if (offset >= seglen) {
				offset -= seglen;
				continue;
			}
			seglen -= offset;
			from += offset;
			offset = 0;
		}
L
Linus Torvalds 已提交
1149 1150

		while (seglen > 0) {
1151 1152
			int copy = 0;
			int max = size_goal;
L
Linus Torvalds 已提交
1153

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

1161
			if (copy <= 0) {
L
Linus Torvalds 已提交
1162 1163 1164 1165 1166 1167 1168
new_segment:
				/* Allocate new segment. If the interface is SG,
				 * allocate skb fitting to single page.
				 */
				if (!sk_stream_memory_free(sk))
					goto wait_for_sndbuf;

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

1175 1176 1177 1178 1179 1180 1181
				/*
				 * All packets are restored as if they have
				 * already been sent.
				 */
				if (tp->repair)
					TCP_SKB_CB(skb)->when = tcp_time_stamp;

L
Linus Torvalds 已提交
1182 1183 1184
				/*
				 * Check whether we can use HW checksum.
				 */
1185
				if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1186
					skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
1187

1188
				skb_entail(sk, skb);
1189
				copy = size_goal;
1190
				max = size_goal;
L
Linus Torvalds 已提交
1191 1192 1193 1194 1195 1196 1197
			}

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

			/* Where to copy to? */
1198
			if (skb_availroom(skb) > 0) {
L
Linus Torvalds 已提交
1199
				/* We have some space in skb head. Superb! */
1200
				copy = min_t(int, copy, skb_availroom(skb));
1201 1202
				err = skb_add_data_nocache(sk, skb, from, copy);
				if (err)
L
Linus Torvalds 已提交
1203 1204
					goto do_fault;
			} else {
1205
				bool merge = true;
L
Linus Torvalds 已提交
1206
				int i = skb_shinfo(skb)->nr_frags;
1207 1208 1209 1210 1211 1212 1213 1214 1215 1216
				struct page_frag *pfrag = sk_page_frag(sk);

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

				if (!skb_can_coalesce(skb, i, pfrag->page,
						      pfrag->offset)) {
					if (i == MAX_SKB_FRAGS || !sg) {
						tcp_mark_push(tp, skb);
						goto new_segment;
L
Linus Torvalds 已提交
1217
					}
1218 1219
					merge = false;
				}
1220

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

1223
				if (!sk_wmem_schedule(sk, copy))
1224
					goto wait_for_memory;
L
Linus Torvalds 已提交
1225

1226
				err = skb_copy_to_page_nocache(sk, from, skb,
1227 1228 1229 1230
							       pfrag->page,
							       pfrag->offset,
							       copy);
				if (err)
L
Linus Torvalds 已提交
1231 1232 1233 1234
					goto do_error;

				/* Update the skb. */
				if (merge) {
E
Eric Dumazet 已提交
1235
					skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
1236
				} else {
1237 1238 1239
					skb_fill_page_desc(skb, i, pfrag->page,
							   pfrag->offset, copy);
					get_page(pfrag->page);
L
Linus Torvalds 已提交
1240
				}
1241
				pfrag->offset += copy;
L
Linus Torvalds 已提交
1242 1243 1244
			}

			if (!copied)
E
Eric Dumazet 已提交
1245
				TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
1246 1247 1248

			tp->write_seq += copy;
			TCP_SKB_CB(skb)->end_seq += copy;
1249
			skb_shinfo(skb)->gso_segs = 0;
L
Linus Torvalds 已提交
1250 1251 1252 1253 1254 1255

			from += copy;
			copied += copy;
			if ((seglen -= copy) == 0 && iovlen == 0)
				goto out;

P
Pavel Emelyanov 已提交
1256
			if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1257 1258 1259 1260
				continue;

			if (forced_push(tp)) {
				tcp_mark_push(tp, skb);
1261
				__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1262
			} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
1263 1264 1265 1266 1267 1268
				tcp_push_one(sk, mss_now);
			continue;

wait_for_sndbuf:
			set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
1269
			if (copied)
E
Eric Dumazet 已提交
1270 1271
				tcp_push(sk, flags & ~MSG_MORE, mss_now,
					 TCP_NAGLE_PUSH, size_goal);
L
Linus Torvalds 已提交
1272 1273 1274 1275

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

I
Ilpo Järvinen 已提交
1276
			mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1277 1278 1279 1280
		}
	}

out:
1281
	if (copied)
E
Eric Dumazet 已提交
1282
		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
L
Linus Torvalds 已提交
1283
	release_sock(sk);
1284
	return copied + copied_syn;
L
Linus Torvalds 已提交
1285 1286 1287

do_fault:
	if (!skb->len) {
1288 1289 1290 1291 1292
		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);
1293
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1294 1295 1296
	}

do_error:
1297
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1298 1299 1300 1301 1302 1303
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1304
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1305 1306 1307 1308 1309 1310

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

1311
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
{
	struct tcp_sock *tp = tcp_sk(sk);

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

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

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

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

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

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

		return err ? -EFAULT : len;
	}

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

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

P
Pavel Emelyanov 已提交
1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
{
	struct sk_buff *skb;
	int copied = 0, err = 0;

	/* XXX -- need to support SO_PEEK_OFF */

	skb_queue_walk(&sk->sk_write_queue, skb) {
		err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, skb->len);
		if (err)
			break;

		copied += skb->len;
	}

	return err ?: copied;
}

L
Linus Torvalds 已提交
1373 1374 1375 1376 1377 1378
/* 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.
 */
1379
void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1380 1381
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1382
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1383 1384 1385

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

1386
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1387
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1388
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1389

1390 1391
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1392 1393
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1394
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1395
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1396
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1397 1398 1399 1400 1401 1402
		    /*
		     * 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.
		     */
1403 1404 1405 1406 1407
		    (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
1408
			time_to_ack = true;
L
Linus Torvalds 已提交
1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429
	}

	/* 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
1430
				time_to_ack = true;
L
Linus Torvalds 已提交
1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441
		}
	}
	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);

1442
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1443 1444 1445 1446 1447

	/* 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
1448
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1449 1450 1451 1452 1453 1454
	local_bh_enable();

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

1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465
#ifdef CONFIG_NET_DMA
static void tcp_service_net_dma(struct sock *sk, bool wait)
{
	dma_cookie_t done, used;
	dma_cookie_t last_issued;
	struct tcp_sock *tp = tcp_sk(sk);

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

	last_issued = tp->ucopy.dma_cookie;
1466
	dma_async_issue_pending(tp->ucopy.dma_chan);
1467 1468

	do {
1469
		if (dma_async_is_tx_complete(tp->ucopy.dma_chan,
1470
					      last_issued, &done,
1471
					      &used) == DMA_COMPLETE) {
1472 1473 1474 1475 1476 1477 1478
			/* Safe to free early-copied skbs now */
			__skb_queue_purge(&sk->sk_async_wait_queue);
			break;
		} else {
			struct sk_buff *skb;
			while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
			       (dma_async_is_complete(skb->dma_cookie, done,
1479
						      used) == DMA_COMPLETE)) {
1480 1481 1482 1483 1484 1485 1486 1487
				__skb_dequeue(&sk->sk_async_wait_queue);
				kfree_skb(skb);
			}
		}
	} while (wait);
}
#endif

1488
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
L
Linus Torvalds 已提交
1489 1490 1491 1492
{
	struct sk_buff *skb;
	u32 offset;

1493
	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
L
Linus Torvalds 已提交
1494
		offset = seq - TCP_SKB_CB(skb)->seq;
1495
		if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1496
			offset--;
1497
		if (offset < skb->len || tcp_hdr(skb)->fin) {
L
Linus Torvalds 已提交
1498 1499 1500
			*off = offset;
			return skb;
		}
1501 1502 1503 1504 1505
		/* This looks weird, but this can happen if TCP collapsing
		 * splitted a fat GRO packet, while we released socket lock
		 * in skb_splice_bits()
		 */
		sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533
	}
	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) {
1534 1535
			int used;
			size_t len;
L
Linus Torvalds 已提交
1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546

			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);
1547
			if (used <= 0) {
1548 1549 1550 1551
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1552 1553 1554 1555
				seq += used;
				copied += used;
				offset += used;
			}
1556
			/* If recv_actor drops the lock (e.g. TCP splice
1557 1558 1559 1560
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1561 1562
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1563
				break;
1564 1565 1566 1567 1568
			/* 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
1569
		}
1570
		if (tcp_hdr(skb)->fin) {
E
Eric Dumazet 已提交
1571
			sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1572 1573 1574
			++seq;
			break;
		}
E
Eric Dumazet 已提交
1575
		sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1576 1577
		if (!desc->count)
			break;
1578
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1579 1580 1581 1582 1583 1584
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1585 1586
	if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
1587
		tcp_cleanup_rbuf(sk, copied);
1588
	}
L
Linus Torvalds 已提交
1589 1590
	return copied;
}
E
Eric Dumazet 已提交
1591
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612

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

int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len, int nonblock, int flags, int *addr_len)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int copied = 0;
	u32 peek_seq;
	u32 *seq;
	unsigned long used;
	int err;
	int target;		/* Read at least this many bytes */
	long timeo;
	struct task_struct *user_recv = NULL;
E
Eric Dumazet 已提交
1613
	bool copied_early = false;
1614
	struct sk_buff *skb;
I
Ilpo Järvinen 已提交
1615
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1616

1617 1618 1619
	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
	    (sk->sk_state == TCP_ESTABLISHED))
		sk_busy_loop(sk, nonblock);
1620

L
Linus Torvalds 已提交
1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632
	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
1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647
	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
1648 1649 1650 1651 1652 1653 1654 1655
	seq = &tp->copied_seq;
	if (flags & MSG_PEEK) {
		peek_seq = tp->copied_seq;
		seq = &peek_seq;
	}

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

C
Chris Leech 已提交
1656 1657 1658
#ifdef CONFIG_NET_DMA
	tp->ucopy.dma_chan = NULL;
	preempt_disable();
1659
	skb = skb_peek_tail(&sk->sk_receive_queue);
A
Andrew Morton 已提交
1660 1661 1662 1663 1664 1665 1666 1667
	{
		int available = 0;

		if (skb)
			available = TCP_SKB_CB(skb)->seq + skb->len - (*seq);
		if ((available < target) &&
		    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
		    !sysctl_tcp_low_latency &&
1668
		    net_dma_find_channel()) {
A
Andrew Morton 已提交
1669 1670 1671 1672 1673 1674 1675
			preempt_enable_no_resched();
			tp->ucopy.pinned_list =
					dma_pin_iovec_pages(msg->msg_iov, len);
		} else {
			preempt_enable_no_resched();
		}
	}
C
Chris Leech 已提交
1676 1677
#endif

L
Linus Torvalds 已提交
1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692
	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. */

1693
		skb_queue_walk(&sk->sk_receive_queue, skb) {
L
Linus Torvalds 已提交
1694 1695 1696
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1697
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1698 1699 1700
				 "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
1701
				break;
1702

L
Linus Torvalds 已提交
1703
			offset = *seq - TCP_SKB_CB(skb)->seq;
1704
			if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1705 1706 1707
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1708
			if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1709
				goto found_fin_ok;
J
Joe Perches 已提交
1710 1711 1712
			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);
1713
		}
L
Linus Torvalds 已提交
1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724

		/* 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 ||
1725
			    signal_pending(current))
L
Linus Torvalds 已提交
1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760
				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;
			}
		}

1761
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1762

1763
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1764 1765 1766 1767 1768 1769 1770 1771 1772
			/* Install new reader */
			if (!user_recv && !(flags & (MSG_TRUNC | MSG_PEEK))) {
				user_recv = current;
				tp->ucopy.task = user_recv;
				tp->ucopy.iov = msg->msg_iov;
			}

			tp->ucopy.len = len;

1773 1774
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801

			/* 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.
			 */
1802
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1803 1804 1805 1806 1807
				goto do_prequeue;

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

1808
#ifdef CONFIG_NET_DMA
1809 1810 1811 1812 1813 1814
		if (tp->ucopy.dma_chan) {
			if (tp->rcv_wnd == 0 &&
			    !skb_queue_empty(&sk->sk_async_wait_queue)) {
				tcp_service_net_dma(sk, true);
				tcp_cleanup_rbuf(sk, copied);
			} else
1815
				dma_async_issue_pending(tp->ucopy.dma_chan);
1816
		}
1817
#endif
L
Linus Torvalds 已提交
1818 1819 1820 1821 1822 1823 1824
		if (copied >= target) {
			/* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
		} else
			sk_wait_data(sk, &timeo);

C
Chris Leech 已提交
1825
#ifdef CONFIG_NET_DMA
1826
		tcp_service_net_dma(sk, false);  /* Don't block */
C
Chris Leech 已提交
1827 1828 1829
		tp->ucopy.wakeup = 0;
#endif

L
Linus Torvalds 已提交
1830 1831 1832 1833 1834 1835
		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

			if ((chunk = len - tp->ucopy.len) != 0) {
1836
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1837 1838 1839 1840 1841
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1842
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1843 1844 1845 1846
do_prequeue:
				tcp_prequeue_process(sk);

				if ((chunk = len - tp->ucopy.len) != 0) {
1847
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1848 1849 1850 1851 1852
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1853 1854
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1855 1856 1857
			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
1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874
			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
1875
						urg_hole++;
L
Linus Torvalds 已提交
1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
C
Chris Leech 已提交
1887 1888
#ifdef CONFIG_NET_DMA
			if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1889
				tp->ucopy.dma_chan = net_dma_find_channel();
C
Chris Leech 已提交
1890 1891 1892 1893 1894 1895 1896 1897 1898

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

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

1899 1900
					pr_alert("%s: dma_cookie < 0\n",
						 __func__);
C
Chris Leech 已提交
1901 1902 1903 1904 1905 1906

					/* Exception. Bailout! */
					if (!copied)
						copied = -EFAULT;
					break;
				}
1907

1908
				dma_async_issue_pending(tp->ucopy.dma_chan);
1909

C
Chris Leech 已提交
1910
				if ((offset + used) == skb->len)
E
Eric Dumazet 已提交
1911
					copied_early = true;
C
Chris Leech 已提交
1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923

			} else
#endif
			{
				err = skb_copy_datagram_iovec(skb, offset,
						msg->msg_iov, used);
				if (err) {
					/* Exception. Bailout! */
					if (!copied)
						copied = -EFAULT;
					break;
				}
L
Linus Torvalds 已提交
1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935
			}
		}

		*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;
1936
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1937 1938 1939 1940
		}
		if (used + offset < skb->len)
			continue;

1941
		if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1942
			goto found_fin_ok;
C
Chris Leech 已提交
1943 1944
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
E
Eric Dumazet 已提交
1945
			copied_early = false;
C
Chris Leech 已提交
1946
		}
L
Linus Torvalds 已提交
1947 1948 1949 1950 1951
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
C
Chris Leech 已提交
1952 1953
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
E
Eric Dumazet 已提交
1954
			copied_early = false;
C
Chris Leech 已提交
1955
		}
L
Linus Torvalds 已提交
1956 1957 1958 1959
		break;
	} while (len > 0);

	if (user_recv) {
1960
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1961 1962 1963 1964 1965 1966 1967
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1968
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1969 1970 1971 1972 1973 1974 1975 1976 1977
				len -= chunk;
				copied += chunk;
			}
		}

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

C
Chris Leech 已提交
1978
#ifdef CONFIG_NET_DMA
1979 1980
	tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
	tp->ucopy.dma_chan = NULL;
C
Chris Leech 已提交
1981 1982 1983 1984 1985 1986 1987

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

L
Linus Torvalds 已提交
1988 1989 1990 1991 1992
	/* 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. */
1993
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1994 1995 1996 1997 1998 1999 2000 2001 2002

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
2003
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
2004
	goto out;
P
Pavel Emelyanov 已提交
2005 2006 2007 2008

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
2009
}
E
Eric Dumazet 已提交
2010
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
2011

I
Ilpo Järvinen 已提交
2012 2013 2014 2015 2016 2017 2018
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
2019
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
2020 2021 2022 2023
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
2024
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
2025 2026 2027 2028

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2029
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
2030 2031
		/* fall through */
	default:
2032
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
2033
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
2034 2035 2036 2037 2038 2039 2040 2041
	}

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

#ifdef STATE_TRACE
2042
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
2043 2044 2045 2046
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
2047 2048 2049 2050 2051 2052 2053
/*
 *	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.
 */

2054
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081
  /* current state:        new state:      action:	*/
  /* (Invalid)		*/ TCP_CLOSE,
  /* TCP_ESTABLISHED	*/ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  /* TCP_SYN_SENT	*/ TCP_CLOSE,
  /* TCP_SYN_RECV	*/ TCP_FIN_WAIT1 | TCP_ACTION_FIN,
  /* TCP_FIN_WAIT1	*/ TCP_FIN_WAIT1,
  /* TCP_FIN_WAIT2	*/ TCP_FIN_WAIT2,
  /* TCP_TIME_WAIT	*/ TCP_CLOSE,
  /* TCP_CLOSE		*/ TCP_CLOSE,
  /* TCP_CLOSE_WAIT	*/ TCP_LAST_ACK  | TCP_ACTION_FIN,
  /* TCP_LAST_ACK	*/ TCP_LAST_ACK,
  /* TCP_LISTEN		*/ TCP_CLOSE,
  /* TCP_CLOSING	*/ TCP_CLOSING,
};

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

	tcp_set_state(sk, ns);

	return next & TCP_ACTION_FIN;
}

/*
 *	Shutdown the sending side of a connection. Much like close except
2082
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102
 */

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
2103
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
2104

A
Arun Sharma 已提交
2105 2106 2107 2108 2109 2110 2111
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);

2112 2113 2114 2115
	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
2116 2117 2118
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
2119 2120 2121 2122
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
2123
	int state;
L
Linus Torvalds 已提交
2124 2125 2126 2127 2128 2129 2130 2131

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

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

		/* Special case. */
2132
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2133 2134 2135 2136 2137 2138 2139 2140 2141 2142

		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) {
		u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq -
2143
			  tcp_hdr(skb)->fin;
L
Linus Torvalds 已提交
2144 2145 2146 2147
		data_was_unread += len;
		__kfree_skb(skb);
	}

2148
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2149

2150 2151 2152 2153
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2154 2155 2156 2157 2158 2159
	/* 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
2160
	 */
P
Pavel Emelyanov 已提交
2161 2162 2163
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2164
		/* Unread data was tossed, zap the connection. */
2165
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2166
		tcp_set_state(sk, TCP_CLOSE);
2167
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2168 2169 2170
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2171
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196
	} 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
2197 2198 2199 2200
		 * 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
2201 2202 2203 2204 2205 2206 2207
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2208 2209 2210 2211
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2212 2213 2214 2215 2216 2217 2218 2219 2220
	/* 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);
2221
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2222

H
Herbert Xu 已提交
2223 2224
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2225 2226 2227
	/* 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
2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247

	/*	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.
	 *	We use a 3 minute timeout (about the same as BSD) then kill
	 *	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);
2248 2249
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2250
		} else {
2251
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2252 2253

			if (tmo > TCP_TIMEWAIT_LEN) {
2254 2255
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2256 2257 2258 2259 2260 2261 2262
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2263
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2264
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2265 2266
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2267 2268
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2269 2270 2271
		}
	}

2272 2273 2274 2275 2276 2277 2278 2279
	if (sk->sk_state == TCP_CLOSE) {
		struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
		/* We could get here with a non-NULL req if the socket is
		 * aborted (e.g., closed with unread data) before 3WHS
		 * finishes.
		 */
		if (req != NULL)
			reqsk_fastopen_remove(sk, req, false);
2280
		inet_csk_destroy_sock(sk);
2281
	}
L
Linus Torvalds 已提交
2282 2283 2284 2285 2286 2287 2288
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2289
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2290 2291 2292

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

E
Eric Dumazet 已提交
2293
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2294 2295 2296 2297 2298 2299 2300 2301 2302
{
	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);
2303
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2304 2305 2306 2307 2308 2309 2310 2311 2312
	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) {
2313
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2314 2315
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2316 2317 2318
	} 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
2319
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2320 2321 2322 2323 2324 2325 2326 2327 2328
		 * 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);
2329
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2330
	__skb_queue_purge(&tp->out_of_order_queue);
C
Chris Leech 已提交
2331 2332 2333
#ifdef CONFIG_NET_DMA
	__skb_queue_purge(&sk->sk_async_wait_queue);
#endif
L
Linus Torvalds 已提交
2334

E
Eric Dumazet 已提交
2335
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2336 2337 2338 2339 2340 2341 2342 2343 2344

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

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);
	tp->srtt = 0;
	if ((tp->write_seq += tp->max_window + 2) == 0)
		tp->write_seq = 1;
2345
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2346
	tp->snd_cwnd = 2;
2347
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2348
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2349
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2350
	tp->snd_cwnd_cnt = 0;
2351
	tp->window_clamp = 0;
2352
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2353
	tcp_clear_retrans(tp);
2354
	inet_csk_delack_init(sk);
2355
	tcp_init_send_head(sk);
2356
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2357 2358
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2359
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2360 2361 2362 2363

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2364
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2365

2366 2367 2368 2369 2370 2371 2372
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
2373
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2374
{
2375
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2376 2377 2378
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2379 2380
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2381
{
2382
	struct tcp_repair_opt opt;
2383

2384 2385
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2386 2387 2388
			return -EFAULT;

		optbuf++;
2389
		len -= sizeof(opt);
2390

2391 2392 2393
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2394
			break;
2395
		case TCPOPT_WINDOW:
2396 2397 2398 2399 2400 2401
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2402

2403 2404 2405 2406
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2407 2408
			break;
		case TCPOPT_SACK_PERM:
2409 2410 2411
			if (opt.opt_val != 0)
				return -EINVAL;

2412 2413 2414 2415 2416
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2417 2418 2419
			if (opt.opt_val != 0)
				return -EINVAL;

2420 2421 2422 2423 2424 2425 2426 2427
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

L
Linus Torvalds 已提交
2428 2429 2430
/*
 *	Socket option code for TCP.
 */
2431
static int do_tcp_setsockopt(struct sock *sk, int level,
2432
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2433 2434
{
	struct tcp_sock *tp = tcp_sk(sk);
2435
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2436 2437 2438
	int val;
	int err = 0;

2439 2440 2441
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2442 2443 2444 2445 2446 2447
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2448
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2449 2450 2451 2452 2453
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2454
		err = tcp_set_congestion_control(sk, name);
2455 2456 2457
		release_sock(sk);
		return err;
	}
2458 2459 2460
	default:
		/* fallthru */
		break;
2461
	}
2462

L
Linus Torvalds 已提交
2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475
	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 */
2476
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493
			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;
2494
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2495 2496 2497 2498 2499
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2500 2501 2502 2503 2504 2505 2506
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2507 2508 2509
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
2510
		else {
A
Andreas Petlund 已提交
2511
			tp->thin_dupack = val;
Y
Yuchung Cheng 已提交
2512 2513
			if (tp->thin_dupack)
				tcp_disable_early_retrans(tp);
2514
		}
A
Andreas Petlund 已提交
2515 2516
		break;

P
Pavel Emelyanov 已提交
2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552
	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;

2553 2554 2555 2556
	case TCP_REPAIR_OPTIONS:
		if (!tp->repair)
			err = -EINVAL;
		else if (sk->sk_state == TCP_ESTABLISHED)
2557 2558 2559
			err = tcp_repair_options_est(tp,
					(struct tcp_repair_opt __user *)optval,
					optlen);
2560 2561 2562 2563
		else
			err = -EPERM;
		break;

L
Linus Torvalds 已提交
2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581
	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;
2582
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593
		}
		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))) {
2594
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2595 2596 2597 2598
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2599
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
			}
		}
		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
2619
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631
		break;

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

	case TCP_DEFER_ACCEPT:
2632 2633 2634 2635
		/* 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
2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651
		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) {
2652
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2653
		} else {
2654
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2655 2656
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2657 2658
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2659
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2660
				if (!(val & 1))
2661
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2662 2663 2664 2665
			}
		}
		break;

2666 2667 2668 2669 2670 2671
#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
2672 2673 2674 2675
	case TCP_USER_TIMEOUT:
		/* Cap the max timeout in ms TCP will retry/retrans
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2676 2677 2678 2679
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2680
		break;
2681 2682 2683 2684 2685 2686 2687 2688

	case TCP_FASTOPEN:
		if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
		    TCPF_LISTEN)))
			err = fastopen_init_queue(sk, val);
		else
			err = -EINVAL;
		break;
2689 2690 2691 2692 2693 2694
	case TCP_TIMESTAMP:
		if (!tp->repair)
			err = -EPERM;
		else
			tp->tsoffset = val - tcp_time_stamp;
		break;
2695 2696 2697 2698
	case TCP_NOTSENT_LOWAT:
		tp->notsent_lowat = val;
		sk->sk_write_space(sk);
		break;
L
Linus Torvalds 已提交
2699 2700 2701
	default:
		err = -ENOPROTOOPT;
		break;
2702 2703
	}

L
Linus Torvalds 已提交
2704 2705 2706 2707
	release_sock(sk);
	return err;
}

2708
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2709
		   unsigned int optlen)
2710
{
2711
	const struct inet_connection_sock *icsk = inet_csk(sk);
2712 2713 2714 2715 2716 2717

	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
2718
EXPORT_SYMBOL(tcp_setsockopt);
2719 2720

#ifdef CONFIG_COMPAT
2721
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2722
			  char __user *optval, unsigned int optlen)
2723
{
2724 2725 2726
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2727 2728
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2729
EXPORT_SYMBOL(compat_tcp_setsockopt);
2730 2731
#endif

L
Linus Torvalds 已提交
2732
/* Return information about state of tcp endpoint in API format. */
2733
void tcp_get_info(const struct sock *sk, struct tcp_info *info)
L
Linus Torvalds 已提交
2734
{
2735
	const struct tcp_sock *tp = tcp_sk(sk);
2736
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2737 2738 2739 2740 2741
	u32 now = tcp_time_stamp;

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

	info->tcpi_state = sk->sk_state;
2742
	info->tcpi_ca_state = icsk->icsk_ca_state;
2743
	info->tcpi_retransmits = icsk->icsk_retransmits;
2744
	info->tcpi_probes = icsk->icsk_probes_out;
2745
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2746 2747 2748

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2749
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2750 2751 2752 2753 2754
		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;
2755
	}
L
Linus Torvalds 已提交
2756

E
Eric Dumazet 已提交
2757
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2758
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2759 2760
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2761 2762
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2763

2764 2765
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2766
	info->tcpi_snd_mss = tp->mss_cache;
2767
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2768

2769 2770 2771 2772 2773 2774 2775
	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
2776 2777 2778 2779 2780
	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);
2781
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2782 2783
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2784
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799
	info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
	info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
	info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
	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;
}
EXPORT_SYMBOL_GPL(tcp_get_info);

2800 2801
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2802
{
2803
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816
	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:
2817
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2818 2819
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2820 2821
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2822 2823 2824 2825 2826 2827 2828 2829
		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
2830
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2831 2832
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2833
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2834 2835
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2836
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2837 2838
		break;
	case TCP_SYNCNT:
2839
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2840 2841 2842 2843 2844 2845 2846
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2847 2848
		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
2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868
		break;
	case TCP_WINDOW_CLAMP:
		val = tp->window_clamp;
		break;
	case TCP_INFO: {
		struct tcp_info info;

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

		tcp_get_info(sk, &info);

		len = min_t(unsigned int, len, sizeof(info));
		if (put_user(len, optlen))
			return -EFAULT;
		if (copy_to_user(optval, &info, len))
			return -EFAULT;
		return 0;
	}
	case TCP_QUICKACK:
2869
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2870
		break;
2871 2872 2873 2874 2875 2876 2877

	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;
2878
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2879 2880
			return -EFAULT;
		return 0;
2881

2882 2883 2884 2885 2886 2887
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2888

P
Pavel Emelyanov 已提交
2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908
	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;

2909 2910 2911
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
2912 2913 2914
	case TCP_TIMESTAMP:
		val = tcp_time_stamp + tp->tsoffset;
		break;
2915 2916 2917
	case TCP_NOTSENT_LOWAT:
		val = tp->notsent_lowat;
		break;
L
Linus Torvalds 已提交
2918 2919
	default:
		return -ENOPROTOOPT;
2920
	}
L
Linus Torvalds 已提交
2921 2922 2923 2924 2925 2926 2927 2928

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

2929 2930 2931 2932 2933 2934 2935 2936 2937 2938
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
2939
EXPORT_SYMBOL(tcp_getsockopt);
2940 2941

#ifdef CONFIG_COMPAT
2942 2943
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2944
{
2945 2946 2947
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2948 2949
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2950
EXPORT_SYMBOL(compat_tcp_getsockopt);
2951
#endif
L
Linus Torvalds 已提交
2952

2953
#ifdef CONFIG_TCP_MD5SIG
2954 2955
static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool __read_mostly;
static DEFINE_MUTEX(tcp_md5sig_mutex);
2956

2957
static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
2958 2959
{
	int cpu;
2960

2961
	for_each_possible_cpu(cpu) {
2962 2963 2964 2965
		struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);

		if (p->md5_desc.tfm)
			crypto_free_hash(p->md5_desc.tfm);
2966 2967 2968 2969
	}
	free_percpu(pool);
}

2970
static void __tcp_alloc_md5sig_pool(void)
2971 2972
{
	int cpu;
2973
	struct tcp_md5sig_pool __percpu *pool;
2974

2975
	pool = alloc_percpu(struct tcp_md5sig_pool);
2976
	if (!pool)
2977
		return;
2978 2979 2980 2981 2982

	for_each_possible_cpu(cpu) {
		struct crypto_hash *hash;

		hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
2983
		if (IS_ERR_OR_NULL(hash))
2984 2985
			goto out_free;

2986
		per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
2987
	}
2988 2989 2990 2991 2992 2993
	/* before setting tcp_md5sig_pool, we must commit all writes
	 * to memory. See ACCESS_ONCE() in tcp_get_md5sig_pool()
	 */
	smp_wmb();
	tcp_md5sig_pool = pool;
	return;
2994 2995 2996 2997
out_free:
	__tcp_free_md5sig_pool(pool);
}

2998
bool tcp_alloc_md5sig_pool(void)
2999
{
3000 3001 3002 3003 3004 3005 3006
	if (unlikely(!tcp_md5sig_pool)) {
		mutex_lock(&tcp_md5sig_mutex);

		if (!tcp_md5sig_pool)
			__tcp_alloc_md5sig_pool();

		mutex_unlock(&tcp_md5sig_mutex);
3007
	}
3008
	return tcp_md5sig_pool != NULL;
3009 3010 3011
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
3012 3013 3014 3015 3016 3017 3018 3019 3020

/**
 *	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)
3021
{
3022
	struct tcp_md5sig_pool __percpu *p;
E
Eric Dumazet 已提交
3023 3024

	local_bh_disable();
3025
	p = ACCESS_ONCE(tcp_md5sig_pool);
E
Eric Dumazet 已提交
3026
	if (p)
3027
		return __this_cpu_ptr(p);
3028

E
Eric Dumazet 已提交
3029 3030 3031 3032
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
3033

3034
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3035
			const struct tcphdr *th)
3036 3037
{
	struct scatterlist sg;
3038
	struct tcphdr hdr;
3039 3040
	int err;

3041 3042 3043 3044
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

3045
	/* options aren't included in the hash */
3046 3047
	sg_init_one(&sg, &hdr, sizeof(hdr));
	err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3048 3049 3050 3051 3052
	return err;
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3053
			  const struct sk_buff *skb, unsigned int header_len)
3054 3055 3056 3057
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
	struct hash_desc *desc = &hp->md5_desc;
3058 3059 3060
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
3061
	const struct skb_shared_info *shi = skb_shinfo(skb);
3062
	struct sk_buff *frag_iter;
3063 3064 3065 3066 3067 3068 3069 3070 3071

	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
3072 3073 3074 3075 3076
		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
3077
		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3078 3079 3080
			return 1;
	}

3081 3082 3083 3084
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3085 3086 3087 3088
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

3089
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3090 3091 3092 3093 3094 3095 3096 3097
{
	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);

3098 3099
#endif

A
Andi Kleen 已提交
3100 3101
void tcp_done(struct sock *sk)
{
3102 3103
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

3104
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3105
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3106 3107 3108

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
3109 3110
	if (req != NULL)
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
3111 3112 3113 3114 3115 3116 3117 3118 3119 3120

	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);

3121
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3122 3123 3124 3125

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
3126 3127
	ssize_t ret;

L
Linus Torvalds 已提交
3128 3129
	if (!str)
		return 0;
3130 3131 3132 3133 3134

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

L
Linus Torvalds 已提交
3135 3136 3137 3138
	return 1;
}
__setup("thash_entries=", set_thash_entries);

3139
static void tcp_init_mem(void)
3140 3141 3142
{
	unsigned long limit = nr_free_buffer_pages() / 8;
	limit = max(limit, 128UL);
3143 3144 3145
	sysctl_tcp_mem[0] = limit / 4 * 3;
	sysctl_tcp_mem[1] = limit;
	sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
3146 3147
}

L
Linus Torvalds 已提交
3148 3149 3150
void __init tcp_init(void)
{
	struct sk_buff *skb = NULL;
3151
	unsigned long limit;
3152
	int max_rshare, max_wshare, cnt;
3153
	unsigned int i;
L
Linus Torvalds 已提交
3154

3155
	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
L
Linus Torvalds 已提交
3156

3157
	percpu_counter_init(&tcp_sockets_allocated, 0);
3158
	percpu_counter_init(&tcp_orphan_count, 0);
3159 3160 3161
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3162
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3163 3164 3165 3166 3167 3168

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3169
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3170
		alloc_large_system_hash("TCP established",
3171
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3172
					thash_entries,
E
Eric Dumazet 已提交
3173
					17, /* one slot per 128 KB of memory */
3174
					0,
L
Linus Torvalds 已提交
3175
					NULL,
3176
					&tcp_hashinfo.ehash_mask,
3177
					0,
3178
					thash_entries ? 0 : 512 * 1024);
E
Eric Dumazet 已提交
3179
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
3180
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
E
Eric Dumazet 已提交
3181

3182 3183
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3184
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3185
		alloc_large_system_hash("TCP bind",
3186
					sizeof(struct inet_bind_hashbucket),
3187
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3188
					17, /* one slot per 128 KB of memory */
3189
					0,
3190
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3191
					NULL,
3192
					0,
L
Linus Torvalds 已提交
3193
					64 * 1024);
3194
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3195 3196 3197
	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
3198 3199
	}

E
Eric Dumazet 已提交
3200 3201 3202 3203 3204 3205

	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
3206

3207
	tcp_init_mem();
3208
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3209
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3210 3211
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3212

3213
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3214
	sysctl_tcp_wmem[1] = 16*1024;
3215
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3216

3217
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3218
	sysctl_tcp_rmem[1] = 87380;
3219
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3220

3221
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3222
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3223

3224 3225
	tcp_metrics_init();

3226
	tcp_register_congestion_control(&tcp_reno);
3227

E
Eric Dumazet 已提交
3228
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3229
}