tcp.c 94.1 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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int sysctl_tcp_fin_timeout __read_mostly = TCP_FIN_TIMEOUT;
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struct percpu_counter tcp_orphan_count;
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EXPORT_SYMBOL_GPL(tcp_orphan_count);

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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_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;

	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;

	/* TCP Cookie Transactions */
	if (sysctl_tcp_cookie_size > 0) {
		/* Default, cookies without s_data_payload. */
		tp->cookie_values =
			kzalloc(sizeof(*tp->cookie_values),
				sk->sk_allocation);
		if (tp->cookie_values != NULL)
			kref_init(&tp->cookie_values->kref);
	}
	/* Presumed zeroed, in order of appearance:
	 *	cookie_in_always, cookie_out_never,
	 *	s_data_constant, s_data_in, s_data_out
	 */
	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_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)) {
			if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
				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.
				 */
				if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
					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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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
539
	bool slow;
L
Linus Torvalds 已提交
540 541 542 543 544 545

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

E
Eric Dumazet 已提交
546
		slow = lock_sock_fast(sk);
L
Linus Torvalds 已提交
547 548 549 550 551 552
		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)) {
553

L
Linus Torvalds 已提交
554 555
			answ = tp->rcv_nxt - tp->copied_seq;

E
Eric Dumazet 已提交
556 557 558
			/* Subtract 1, if FIN was received */
			if (answ && sock_flag(sk, SOCK_DONE))
				answ--;
L
Linus Torvalds 已提交
559 560
		} else
			answ = tp->urg_seq - tp->copied_seq;
E
Eric Dumazet 已提交
561
		unlock_sock_fast(sk, slow);
L
Linus Torvalds 已提交
562 563 564 565 566 567 568 569 570 571 572 573 574
		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;
575 576 577 578 579 580 581 582 583
	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
584 585
	default:
		return -ENOIOCTLCMD;
586
	}
L
Linus Torvalds 已提交
587 588 589

	return put_user(answ, (int __user *)arg);
}
E
Eric Dumazet 已提交
590
EXPORT_SYMBOL(tcp_ioctl);
L
Linus Torvalds 已提交
591 592 593

static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
594
	TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
L
Linus Torvalds 已提交
595 596 597
	tp->pushed_seq = tp->write_seq;
}

E
Eric Dumazet 已提交
598
static inline bool forced_push(const struct tcp_sock *tp)
L
Linus Torvalds 已提交
599 600 601 602
{
	return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}

603
static inline void skb_entail(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
604
{
605
	struct tcp_sock *tp = tcp_sk(sk);
606 607 608 609
	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
610
	tcb->tcp_flags = TCPHDR_ACK;
611
	tcb->sacked  = 0;
L
Linus Torvalds 已提交
612
	skb_header_release(skb);
613
	tcp_add_write_queue_tail(sk, skb);
614 615
	sk->sk_wmem_queued += skb->truesize;
	sk_mem_charge(sk, skb->truesize);
616
	if (tp->nonagle & TCP_NAGLE_PUSH)
617
		tp->nonagle &= ~TCP_NAGLE_PUSH;
L
Linus Torvalds 已提交
618 619
}

620
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
L
Linus Torvalds 已提交
621
{
I
Ilpo Järvinen 已提交
622
	if (flags & MSG_OOB)
L
Linus Torvalds 已提交
623 624 625
		tp->snd_up = tp->write_seq;
}

626 627
static inline void tcp_push(struct sock *sk, int flags, int mss_now,
			    int nonagle)
L
Linus Torvalds 已提交
628
{
629
	if (tcp_send_head(sk)) {
630 631
		struct tcp_sock *tp = tcp_sk(sk);

L
Linus Torvalds 已提交
632
		if (!(flags & MSG_MORE) || forced_push(tp))
633 634 635
			tcp_mark_push(tp, tcp_write_queue_tail(sk));

		tcp_mark_urg(tp, flags);
636
		__tcp_push_pending_frames(sk, mss_now,
L
Linus Torvalds 已提交
637 638 639 640
					  (flags & MSG_MORE) ? TCP_NAGLE_CORK : nonagle);
	}
}

641 642
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
643 644
{
	struct tcp_splice_state *tss = rd_desc->arg.data;
645
	int ret;
J
Jens Axboe 已提交
646

647 648
	ret = skb_splice_bits(skb, offset, tss->pipe, min(rd_desc->count, len),
			      tss->flags);
649 650 651
	if (ret > 0)
		rd_desc->count -= ret;
	return ret;
J
Jens Axboe 已提交
652 653 654 655 656 657 658
}

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,
659
		.count	  = tss->len,
J
Jens Axboe 已提交
660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
	};

	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;

691
	sock_rps_record_flow(sk);
J
Jens Axboe 已提交
692 693 694 695 696 697 698 699 700 701
	/*
	 * We can't seek on a socket input
	 */
	if (unlikely(*ppos))
		return -ESPIPE;

	ret = spliced = 0;

	lock_sock(sk);

702
	timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
J
Jens Axboe 已提交
703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
	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;

741 742
		if (!timeo)
			break;
J
Jens Axboe 已提交
743 744 745 746
		release_sock(sk);
		lock_sock(sk);

		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
747
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
J
Jens Axboe 已提交
748 749 750 751 752 753 754 755 756 757 758
		    signal_pending(current))
			break;
	}

	release_sock(sk);

	if (spliced)
		return spliced;

	return ret;
}
E
Eric Dumazet 已提交
759
EXPORT_SYMBOL(tcp_splice_read);
J
Jens Axboe 已提交
760

761
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp)
762 763 764 765 766 767 768 769
{
	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) {
770
		if (sk_wmem_schedule(sk, skb->truesize)) {
771
			skb_reserve(skb, sk->sk_prot->max_header);
772 773 774 775
			/*
			 * Make sure that we have exactly size bytes
			 * available to the caller, no more, no less.
			 */
776
			skb->avail_size = size;
777 778 779 780
			return skb;
		}
		__kfree_skb(skb);
	} else {
781
		sk->sk_prot->enter_memory_pressure(sk);
782 783 784 785 786
		sk_stream_moderate_sndbuf(sk);
	}
	return NULL;
}

I
Ilpo Järvinen 已提交
787 788 789 790
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
				       int large_allowed)
{
	struct tcp_sock *tp = tcp_sk(sk);
791
	u32 xmit_size_goal, old_size_goal;
I
Ilpo Järvinen 已提交
792 793 794 795 796 797 798 799 800

	xmit_size_goal = mss_now;

	if (large_allowed && sk_can_gso(sk)) {
		xmit_size_goal = ((sk->sk_gso_max_size - 1) -
				  inet_csk(sk)->icsk_af_ops->net_header_len -
				  inet_csk(sk)->icsk_ext_hdr_len -
				  tp->tcp_header_len);

E
Eric Dumazet 已提交
801 802 803 804
		/* TSQ : try to have two TSO segments in flight */
		xmit_size_goal = min_t(u32, xmit_size_goal,
				       sysctl_tcp_limit_output_bytes >> 1);

I
Ilpo Järvinen 已提交
805
		xmit_size_goal = tcp_bound_to_half_wnd(tp, xmit_size_goal);
806 807 808 809 810 811 812 813

		/* 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 {
814 815 816
			tp->xmit_size_goal_segs =
				min_t(u16, xmit_size_goal / mss_now,
				      sk->sk_gso_max_segs);
817 818
			xmit_size_goal = tp->xmit_size_goal_segs * mss_now;
		}
I
Ilpo Järvinen 已提交
819 820
	}

821
	return max(xmit_size_goal, mss_now);
I
Ilpo Järvinen 已提交
822 823 824 825 826 827 828 829 830 831 832 833
}

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;
}

834 835
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
836 837
{
	struct tcp_sock *tp = tcp_sk(sk);
838
	int mss_now, size_goal;
L
Linus Torvalds 已提交
839 840 841 842
	int err;
	ssize_t copied;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

843 844 845 846 847 848
	/* 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
849 850
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
			goto out_err;
851
	}
L
Linus Torvalds 已提交
852 853 854

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

I
Ilpo Järvinen 已提交
855
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
856 857 858 859
	copied = 0;

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
860
		goto out_err;
L
Linus Torvalds 已提交
861

862
	while (size > 0) {
863
		struct sk_buff *skb = tcp_write_queue_tail(sk);
864 865
		int copy, i;
		bool can_coalesce;
L
Linus Torvalds 已提交
866

867
		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
L
Linus Torvalds 已提交
868 869 870 871
new_segment:
			if (!sk_stream_memory_free(sk))
				goto wait_for_sndbuf;

872
			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);
L
Linus Torvalds 已提交
873 874 875
			if (!skb)
				goto wait_for_memory;

876
			skb_entail(sk, skb);
877
			copy = size_goal;
L
Linus Torvalds 已提交
878 879 880 881 882 883 884 885 886 887 888
		}

		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;
		}
889
		if (!sk_wmem_schedule(sk, copy))
L
Linus Torvalds 已提交
890
			goto wait_for_memory;
891

L
Linus Torvalds 已提交
892
		if (can_coalesce) {
E
Eric Dumazet 已提交
893
			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
894 895 896 897 898 899 900 901 902
		} else {
			get_page(page);
			skb_fill_page_desc(skb, i, page, offset, copy);
		}

		skb->len += copy;
		skb->data_len += copy;
		skb->truesize += copy;
		sk->sk_wmem_queued += copy;
903
		sk_mem_charge(sk, copy);
904
		skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
905 906
		tp->write_seq += copy;
		TCP_SKB_CB(skb)->end_seq += copy;
907
		skb_shinfo(skb)->gso_segs = 0;
L
Linus Torvalds 已提交
908 909

		if (!copied)
E
Eric Dumazet 已提交
910
			TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
911 912

		copied += copy;
913 914
		offset += copy;
		if (!(size -= copy))
L
Linus Torvalds 已提交
915 916
			goto out;

917
		if (skb->len < size_goal || (flags & MSG_OOB))
L
Linus Torvalds 已提交
918 919 920 921
			continue;

		if (forced_push(tp)) {
			tcp_mark_push(tp, skb);
922
			__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
923
		} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
924 925 926 927 928 929
			tcp_push_one(sk, mss_now);
		continue;

wait_for_sndbuf:
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
930
		tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
L
Linus Torvalds 已提交
931 932 933 934

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

I
Ilpo Järvinen 已提交
935
		mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
936 937 938
	}

out:
939
	if (copied && !(flags & MSG_SENDPAGE_NOTLAST))
940
		tcp_push(sk, flags, mss_now, tp->nonagle);
L
Linus Torvalds 已提交
941 942 943 944 945 946 947 948 949
	return copied;

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

950 951
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
L
Linus Torvalds 已提交
952 953 954 955
{
	ssize_t res;

	if (!(sk->sk_route_caps & NETIF_F_SG) ||
956
	    !(sk->sk_route_caps & NETIF_F_ALL_CSUM))
957 958
		return sock_no_sendpage(sk->sk_socket, page, offset, size,
					flags);
L
Linus Torvalds 已提交
959 960

	lock_sock(sk);
961
	res = do_tcp_sendpages(sk, page, offset, size, flags);
L
Linus Torvalds 已提交
962 963 964
	release_sock(sk);
	return res;
}
E
Eric Dumazet 已提交
965
EXPORT_SYMBOL(tcp_sendpage);
L
Linus Torvalds 已提交
966

967
static inline int select_size(const struct sock *sk, bool sg)
L
Linus Torvalds 已提交
968
{
969
	const struct tcp_sock *tp = tcp_sk(sk);
970
	int tmp = tp->mss_cache;
L
Linus Torvalds 已提交
971

K
Krishna Kumar 已提交
972
	if (sg) {
973 974 975 976 977 978
		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 {
979 980 981 982 983 984 985
			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
986 987 988 989

	return tmp;
}

990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
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;
}

1022
int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
L
Linus Torvalds 已提交
1023 1024 1025 1026 1027
		size_t size)
{
	struct iovec *iov;
	struct tcp_sock *tp = tcp_sk(sk);
	struct sk_buff *skb;
1028 1029
	int iovlen, flags, err, copied = 0;
	int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
1030
	bool sg;
L
Linus Torvalds 已提交
1031 1032 1033 1034 1035
	long timeo;

	lock_sock(sk);

	flags = msg->msg_flags;
1036 1037 1038 1039 1040 1041 1042 1043 1044
	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
1045 1046
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);

1047 1048 1049 1050 1051 1052
	/* 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
1053
		if ((err = sk_stream_wait_connect(sk, &timeo)) != 0)
1054
			goto do_error;
1055
	}
L
Linus Torvalds 已提交
1056

P
Pavel Emelyanov 已提交
1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
	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
1070 1071 1072
	/* This should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

I
Ilpo Järvinen 已提交
1073
	mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1074 1075 1076 1077 1078 1079 1080 1081

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

	err = -EPIPE;
	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
1082
		goto out_err;
L
Linus Torvalds 已提交
1083

1084
	sg = !!(sk->sk_route_caps & NETIF_F_SG);
K
Krishna Kumar 已提交
1085

L
Linus Torvalds 已提交
1086
	while (--iovlen >= 0) {
1087
		size_t seglen = iov->iov_len;
L
Linus Torvalds 已提交
1088 1089 1090
		unsigned char __user *from = iov->iov_base;

		iov++;
1091 1092 1093 1094 1095 1096 1097 1098 1099
		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
1100 1101

		while (seglen > 0) {
1102 1103
			int copy = 0;
			int max = size_goal;
L
Linus Torvalds 已提交
1104

1105
			skb = tcp_write_queue_tail(sk);
1106 1107 1108 1109 1110
			if (tcp_send_head(sk)) {
				if (skb->ip_summed == CHECKSUM_NONE)
					max = mss_now;
				copy = max - skb->len;
			}
L
Linus Torvalds 已提交
1111

1112
			if (copy <= 0) {
L
Linus Torvalds 已提交
1113 1114 1115 1116 1117 1118 1119
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
1120 1121 1122
				skb = sk_stream_alloc_skb(sk,
							  select_size(sk, sg),
							  sk->sk_allocation);
L
Linus Torvalds 已提交
1123 1124 1125 1126 1127 1128
				if (!skb)
					goto wait_for_memory;

				/*
				 * Check whether we can use HW checksum.
				 */
1129
				if (sk->sk_route_caps & NETIF_F_ALL_CSUM)
1130
					skb->ip_summed = CHECKSUM_PARTIAL;
L
Linus Torvalds 已提交
1131

1132
				skb_entail(sk, skb);
1133
				copy = size_goal;
1134
				max = size_goal;
L
Linus Torvalds 已提交
1135 1136 1137 1138 1139 1140 1141
			}

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

			/* Where to copy to? */
1142
			if (skb_availroom(skb) > 0) {
L
Linus Torvalds 已提交
1143
				/* We have some space in skb head. Superb! */
1144
				copy = min_t(int, copy, skb_availroom(skb));
1145 1146
				err = skb_add_data_nocache(sk, skb, from, copy);
				if (err)
L
Linus Torvalds 已提交
1147 1148
					goto do_fault;
			} else {
1149
				bool merge = true;
L
Linus Torvalds 已提交
1150
				int i = skb_shinfo(skb)->nr_frags;
1151 1152 1153 1154 1155 1156 1157 1158 1159 1160
				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
1161
					}
1162 1163
					merge = false;
				}
1164

1165
				copy = min_t(int, copy, pfrag->size - pfrag->offset);
1166

1167
				if (!sk_wmem_schedule(sk, copy))
1168
					goto wait_for_memory;
L
Linus Torvalds 已提交
1169

1170
				err = skb_copy_to_page_nocache(sk, from, skb,
1171 1172 1173 1174
							       pfrag->page,
							       pfrag->offset,
							       copy);
				if (err)
L
Linus Torvalds 已提交
1175 1176 1177 1178
					goto do_error;

				/* Update the skb. */
				if (merge) {
E
Eric Dumazet 已提交
1179
					skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
L
Linus Torvalds 已提交
1180
				} else {
1181 1182 1183
					skb_fill_page_desc(skb, i, pfrag->page,
							   pfrag->offset, copy);
					get_page(pfrag->page);
L
Linus Torvalds 已提交
1184
				}
1185
				pfrag->offset += copy;
L
Linus Torvalds 已提交
1186 1187 1188
			}

			if (!copied)
E
Eric Dumazet 已提交
1189
				TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
L
Linus Torvalds 已提交
1190 1191 1192

			tp->write_seq += copy;
			TCP_SKB_CB(skb)->end_seq += copy;
1193
			skb_shinfo(skb)->gso_segs = 0;
L
Linus Torvalds 已提交
1194 1195 1196 1197 1198 1199

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

P
Pavel Emelyanov 已提交
1200
			if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair))
L
Linus Torvalds 已提交
1201 1202 1203 1204
				continue;

			if (forced_push(tp)) {
				tcp_mark_push(tp, skb);
1205
				__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
1206
			} else if (skb == tcp_send_head(sk))
L
Linus Torvalds 已提交
1207 1208 1209 1210 1211 1212
				tcp_push_one(sk, mss_now);
			continue;

wait_for_sndbuf:
			set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
1213
			if (copied)
1214
				tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
L
Linus Torvalds 已提交
1215 1216 1217 1218

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

I
Ilpo Järvinen 已提交
1219
			mss_now = tcp_send_mss(sk, &size_goal, flags);
L
Linus Torvalds 已提交
1220 1221 1222 1223
		}
	}

out:
1224
	if (copied)
1225
		tcp_push(sk, flags, mss_now, tp->nonagle);
L
Linus Torvalds 已提交
1226
	release_sock(sk);
1227
	return copied + copied_syn;
L
Linus Torvalds 已提交
1228 1229 1230

do_fault:
	if (!skb->len) {
1231 1232 1233 1234 1235
		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);
1236
		sk_wmem_free_skb(sk, skb);
L
Linus Torvalds 已提交
1237 1238 1239
	}

do_error:
1240
	if (copied + copied_syn)
L
Linus Torvalds 已提交
1241 1242 1243 1244 1245 1246
		goto out;
out_err:
	err = sk_stream_error(sk, flags, err);
	release_sock(sk);
	return err;
}
E
Eric Dumazet 已提交
1247
EXPORT_SYMBOL(tcp_sendmsg);
L
Linus Torvalds 已提交
1248 1249 1250 1251 1252 1253

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

1254
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
L
Linus Torvalds 已提交
1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
{
	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
1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315
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
1316 1317 1318 1319 1320 1321
/* 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.
 */
1322
void tcp_cleanup_rbuf(struct sock *sk, int copied)
L
Linus Torvalds 已提交
1323 1324
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1325
	bool time_to_ack = false;
L
Linus Torvalds 已提交
1326 1327 1328

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

1329
	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
J
Joe Perches 已提交
1330
	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
1331
	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
L
Linus Torvalds 已提交
1332

1333 1334
	if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1335 1336
		   /* Delayed ACKs frequently hit locked sockets during bulk
		    * receive. */
1337
		if (icsk->icsk_ack.blocked ||
L
Linus Torvalds 已提交
1338
		    /* Once-per-two-segments ACK was not sent by tcp_input.c */
1339
		    tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
L
Linus Torvalds 已提交
1340 1341 1342 1343 1344 1345
		    /*
		     * 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.
		     */
1346 1347 1348 1349 1350
		    (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
1351
			time_to_ack = true;
L
Linus Torvalds 已提交
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
	}

	/* 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
1373
				time_to_ack = true;
L
Linus Torvalds 已提交
1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384
		}
	}
	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);

1385
	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
L
Linus Torvalds 已提交
1386 1387 1388 1389 1390

	/* 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
1391
		sk_backlog_rcv(sk, skb);
L
Linus Torvalds 已提交
1392 1393 1394 1395 1396 1397
	local_bh_enable();

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

1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
#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;
	dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);

	do {
		if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
					      last_issued, &done,
					      &used) == DMA_SUCCESS) {
			/* 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,
						      used) == DMA_SUCCESS)) {
				__skb_dequeue(&sk->sk_async_wait_queue);
				kfree_skb(skb);
			}
		}
	} while (wait);
}
#endif

L
Linus Torvalds 已提交
1431 1432 1433 1434 1435 1436 1437
static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
{
	struct sk_buff *skb;
	u32 offset;

	skb_queue_walk(&sk->sk_receive_queue, skb) {
		offset = seq - TCP_SKB_CB(skb)->seq;
1438
		if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1439
			offset--;
1440
		if (offset < skb->len || tcp_hdr(skb)->fin) {
L
Linus Torvalds 已提交
1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471
			*off = offset;
			return skb;
		}
	}
	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) {
1472 1473
			int used;
			size_t len;
L
Linus Torvalds 已提交
1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484

			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);
1485 1486 1487 1488 1489
			if (used < 0) {
				if (!copied)
					copied = used;
				break;
			} else if (used <= len) {
L
Linus Torvalds 已提交
1490 1491 1492 1493
				seq += used;
				copied += used;
				offset += used;
			}
1494
			/* If recv_actor drops the lock (e.g. TCP splice
1495 1496 1497 1498
			 * receive) the skb pointer might be invalid when
			 * getting here: tcp_collapse might have deleted it
			 * while aggregating skbs from the socket queue.
			 */
1499 1500
			skb = tcp_recv_skb(sk, seq - 1, &offset);
			if (!skb)
L
Linus Torvalds 已提交
1501
				break;
1502 1503 1504 1505 1506
			/* 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
1507
		}
1508
		if (tcp_hdr(skb)->fin) {
E
Eric Dumazet 已提交
1509
			sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1510 1511 1512
			++seq;
			break;
		}
E
Eric Dumazet 已提交
1513
		sk_eat_skb(sk, skb, false);
L
Linus Torvalds 已提交
1514 1515
		if (!desc->count)
			break;
1516
		tp->copied_seq = seq;
L
Linus Torvalds 已提交
1517 1518 1519 1520 1521 1522
	}
	tp->copied_seq = seq;

	tcp_rcv_space_adjust(sk);

	/* Clean up data we have read: This will do ACK frames. */
1523
	if (copied > 0)
1524
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1525 1526
	return copied;
}
E
Eric Dumazet 已提交
1527
EXPORT_SYMBOL(tcp_read_sock);
L
Linus Torvalds 已提交
1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548

/*
 *	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
1549
	bool copied_early = false;
1550
	struct sk_buff *skb;
I
Ilpo Järvinen 已提交
1551
	u32 urg_hole = 0;
L
Linus Torvalds 已提交
1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564

	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
1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
	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
1580 1581 1582 1583 1584 1585 1586 1587
	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
1588 1589 1590
#ifdef CONFIG_NET_DMA
	tp->ucopy.dma_chan = NULL;
	preempt_disable();
1591
	skb = skb_peek_tail(&sk->sk_receive_queue);
A
Andrew Morton 已提交
1592 1593 1594 1595 1596 1597 1598 1599
	{
		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 &&
1600
		    net_dma_find_channel()) {
A
Andrew Morton 已提交
1601 1602 1603 1604 1605 1606 1607
			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
1608 1609
#endif

L
Linus Torvalds 已提交
1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624
	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. */

1625
		skb_queue_walk(&sk->sk_receive_queue, skb) {
L
Linus Torvalds 已提交
1626 1627 1628
			/* Now that we have two receive queues this
			 * shouldn't happen.
			 */
1629
			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
J
Joe Perches 已提交
1630 1631 1632
				 "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
1633
				break;
1634

L
Linus Torvalds 已提交
1635
			offset = *seq - TCP_SKB_CB(skb)->seq;
1636
			if (tcp_hdr(skb)->syn)
L
Linus Torvalds 已提交
1637 1638 1639
				offset--;
			if (offset < skb->len)
				goto found_ok_skb;
1640
			if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1641
				goto found_fin_ok;
J
Joe Perches 已提交
1642 1643 1644
			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);
1645
		}
L
Linus Torvalds 已提交
1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656

		/* 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 ||
1657
			    signal_pending(current))
L
Linus Torvalds 已提交
1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692
				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;
			}
		}

1693
		tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1694

1695
		if (!sysctl_tcp_low_latency && tp->ucopy.task == user_recv) {
L
Linus Torvalds 已提交
1696 1697 1698 1699 1700 1701 1702 1703 1704
			/* 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;

1705 1706
			WARN_ON(tp->copied_seq != tp->rcv_nxt &&
				!(flags & (MSG_PEEK | MSG_TRUNC)));
L
Linus Torvalds 已提交
1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733

			/* 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.
			 */
1734
			if (!skb_queue_empty(&tp->ucopy.prequeue))
L
Linus Torvalds 已提交
1735 1736 1737 1738 1739
				goto do_prequeue;

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

1740
#ifdef CONFIG_NET_DMA
1741 1742 1743 1744 1745 1746 1747 1748
		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
				dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
		}
1749
#endif
L
Linus Torvalds 已提交
1750 1751 1752 1753 1754 1755 1756
		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
1757
#ifdef CONFIG_NET_DMA
1758
		tcp_service_net_dma(sk, false);  /* Don't block */
C
Chris Leech 已提交
1759 1760 1761
		tp->ucopy.wakeup = 0;
#endif

L
Linus Torvalds 已提交
1762 1763 1764 1765 1766 1767
		if (user_recv) {
			int chunk;

			/* __ Restore normal policy in scheduler __ */

			if ((chunk = len - tp->ucopy.len) != 0) {
1768
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
L
Linus Torvalds 已提交
1769 1770 1771 1772 1773
				len -= chunk;
				copied += chunk;
			}

			if (tp->rcv_nxt == tp->copied_seq &&
1774
			    !skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1775 1776 1777 1778
do_prequeue:
				tcp_prequeue_process(sk);

				if ((chunk = len - tp->ucopy.len) != 0) {
1779
					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1780 1781 1782 1783 1784
					len -= chunk;
					copied += chunk;
				}
			}
		}
I
Ilpo Järvinen 已提交
1785 1786
		if ((flags & MSG_PEEK) &&
		    (peek_seq - copied - urg_hole != tp->copied_seq)) {
1787 1788 1789
			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
1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806
			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
1807
						urg_hole++;
L
Linus Torvalds 已提交
1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818
						offset++;
						used--;
						if (!used)
							goto skip_copy;
					}
				} else
					used = urg_offset;
			}
		}

		if (!(flags & MSG_TRUNC)) {
C
Chris Leech 已提交
1819 1820
#ifdef CONFIG_NET_DMA
			if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1821
				tp->ucopy.dma_chan = net_dma_find_channel();
C
Chris Leech 已提交
1822 1823 1824 1825 1826 1827 1828 1829 1830

			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) {

1831 1832
					pr_alert("%s: dma_cookie < 0\n",
						 __func__);
C
Chris Leech 已提交
1833 1834 1835 1836 1837 1838

					/* Exception. Bailout! */
					if (!copied)
						copied = -EFAULT;
					break;
				}
1839 1840 1841

				dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);

C
Chris Leech 已提交
1842
				if ((offset + used) == skb->len)
E
Eric Dumazet 已提交
1843
					copied_early = true;
C
Chris Leech 已提交
1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855

			} 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
1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867
			}
		}

		*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;
1868
			tcp_fast_path_check(sk);
L
Linus Torvalds 已提交
1869 1870 1871 1872
		}
		if (used + offset < skb->len)
			continue;

1873
		if (tcp_hdr(skb)->fin)
L
Linus Torvalds 已提交
1874
			goto found_fin_ok;
C
Chris Leech 已提交
1875 1876
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
E
Eric Dumazet 已提交
1877
			copied_early = false;
C
Chris Leech 已提交
1878
		}
L
Linus Torvalds 已提交
1879 1880 1881 1882 1883
		continue;

	found_fin_ok:
		/* Process the FIN. */
		++*seq;
C
Chris Leech 已提交
1884 1885
		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, copied_early);
E
Eric Dumazet 已提交
1886
			copied_early = false;
C
Chris Leech 已提交
1887
		}
L
Linus Torvalds 已提交
1888 1889 1890 1891
		break;
	} while (len > 0);

	if (user_recv) {
1892
		if (!skb_queue_empty(&tp->ucopy.prequeue)) {
L
Linus Torvalds 已提交
1893 1894 1895 1896 1897 1898 1899
			int chunk;

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

			tcp_prequeue_process(sk);

			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
1900
				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
L
Linus Torvalds 已提交
1901 1902 1903 1904 1905 1906 1907 1908 1909
				len -= chunk;
				copied += chunk;
			}
		}

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

C
Chris Leech 已提交
1910
#ifdef CONFIG_NET_DMA
1911 1912
	tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
	tp->ucopy.dma_chan = NULL;
C
Chris Leech 已提交
1913 1914 1915 1916 1917 1918 1919

	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
1920 1921 1922 1923 1924
	/* 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. */
1925
	tcp_cleanup_rbuf(sk, copied);
L
Linus Torvalds 已提交
1926 1927 1928 1929 1930 1931 1932 1933 1934

	release_sock(sk);
	return copied;

out:
	release_sock(sk);
	return err;

recv_urg:
1935
	err = tcp_recv_urg(sk, msg, len, flags);
L
Linus Torvalds 已提交
1936
	goto out;
P
Pavel Emelyanov 已提交
1937 1938 1939 1940

recv_sndq:
	err = tcp_peek_sndq(sk, msg, len);
	goto out;
L
Linus Torvalds 已提交
1941
}
E
Eric Dumazet 已提交
1942
EXPORT_SYMBOL(tcp_recvmsg);
L
Linus Torvalds 已提交
1943

I
Ilpo Järvinen 已提交
1944 1945 1946 1947 1948 1949 1950
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
1951
			TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1952 1953 1954 1955
		break;

	case TCP_CLOSE:
		if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1956
			TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
I
Ilpo Järvinen 已提交
1957 1958 1959 1960

		sk->sk_prot->unhash(sk);
		if (inet_csk(sk)->icsk_bind_hash &&
		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1961
			inet_put_port(sk);
I
Ilpo Järvinen 已提交
1962 1963
		/* fall through */
	default:
1964
		if (oldstate == TCP_ESTABLISHED)
P
Pavel Emelyanov 已提交
1965
			TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
I
Ilpo Järvinen 已提交
1966 1967 1968 1969 1970 1971 1972 1973
	}

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

#ifdef STATE_TRACE
1974
	SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n", sk, statename[oldstate], statename[state]);
I
Ilpo Järvinen 已提交
1975 1976 1977 1978
#endif
}
EXPORT_SYMBOL_GPL(tcp_set_state);

L
Linus Torvalds 已提交
1979 1980 1981 1982 1983 1984 1985
/*
 *	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.
 */

1986
static const unsigned char new_state[16] = {
L
Linus Torvalds 已提交
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
  /* 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
2014
 *	that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
L
Linus Torvalds 已提交
2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034
 */

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
2035
EXPORT_SYMBOL(tcp_shutdown);
L
Linus Torvalds 已提交
2036

A
Arun Sharma 已提交
2037 2038 2039 2040 2041 2042 2043
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);

2044 2045 2046 2047
	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
2048 2049 2050
	return too_many_orphans || out_of_socket_memory;
}

L
Linus Torvalds 已提交
2051 2052 2053 2054
void tcp_close(struct sock *sk, long timeout)
{
	struct sk_buff *skb;
	int data_was_unread = 0;
H
Herbert Xu 已提交
2055
	int state;
L
Linus Torvalds 已提交
2056 2057 2058 2059 2060 2061 2062 2063

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

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

		/* Special case. */
2064
		inet_csk_listen_stop(sk);
L
Linus Torvalds 已提交
2065 2066 2067 2068 2069 2070 2071 2072 2073 2074

		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 -
2075
			  tcp_hdr(skb)->fin;
L
Linus Torvalds 已提交
2076 2077 2078 2079
		data_was_unread += len;
		__kfree_skb(skb);
	}

2080
	sk_mem_reclaim(sk);
L
Linus Torvalds 已提交
2081

2082 2083 2084 2085
	/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
	if (sk->sk_state == TCP_CLOSE)
		goto adjudge_to_death;

2086 2087 2088 2089 2090 2091
	/* 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
2092
	 */
P
Pavel Emelyanov 已提交
2093 2094 2095
	if (unlikely(tcp_sk(sk)->repair)) {
		sk->sk_prot->disconnect(sk, 0);
	} else if (data_was_unread) {
L
Linus Torvalds 已提交
2096
		/* Unread data was tossed, zap the connection. */
2097
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
L
Linus Torvalds 已提交
2098
		tcp_set_state(sk, TCP_CLOSE);
2099
		tcp_send_active_reset(sk, sk->sk_allocation);
L
Linus Torvalds 已提交
2100 2101 2102
	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
		/* Check zero linger _after_ checking for unread data. */
		sk->sk_prot->disconnect(sk, 0);
2103
		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
L
Linus Torvalds 已提交
2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128
	} 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
2129 2130 2131 2132
		 * 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
2133 2134 2135 2136 2137 2138 2139
		 */
		tcp_send_fin(sk);
	}

	sk_stream_wait_close(sk, timeout);

adjudge_to_death:
H
Herbert Xu 已提交
2140 2141 2142 2143
	state = sk->sk_state;
	sock_hold(sk);
	sock_orphan(sk);

L
Linus Torvalds 已提交
2144 2145 2146 2147 2148 2149 2150 2151 2152
	/* 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);
2153
	WARN_ON(sock_owned_by_user(sk));
L
Linus Torvalds 已提交
2154

H
Herbert Xu 已提交
2155 2156
	percpu_counter_inc(sk->sk_prot->orphan_count);

H
Herbert Xu 已提交
2157 2158 2159
	/* 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
2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179

	/*	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);
2180 2181
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONLINGER);
L
Linus Torvalds 已提交
2182
		} else {
2183
			const int tmo = tcp_fin_time(sk);
L
Linus Torvalds 已提交
2184 2185

			if (tmo > TCP_TIMEWAIT_LEN) {
2186 2187
				inet_csk_reset_keepalive_timer(sk,
						tmo - TCP_TIMEWAIT_LEN);
L
Linus Torvalds 已提交
2188 2189 2190 2191 2192 2193 2194
			} else {
				tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
				goto out;
			}
		}
	}
	if (sk->sk_state != TCP_CLOSE) {
2195
		sk_mem_reclaim(sk);
A
Arun Sharma 已提交
2196
		if (tcp_check_oom(sk, 0)) {
L
Linus Torvalds 已提交
2197 2198
			tcp_set_state(sk, TCP_CLOSE);
			tcp_send_active_reset(sk, GFP_ATOMIC);
2199 2200
			NET_INC_STATS_BH(sock_net(sk),
					LINUX_MIB_TCPABORTONMEMORY);
L
Linus Torvalds 已提交
2201 2202 2203
		}
	}

2204 2205 2206 2207 2208 2209 2210 2211
	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);
2212
		inet_csk_destroy_sock(sk);
2213
	}
L
Linus Torvalds 已提交
2214 2215 2216 2217 2218 2219 2220
	/* Otherwise, socket is reprieved until protocol close. */

out:
	bh_unlock_sock(sk);
	local_bh_enable();
	sock_put(sk);
}
E
Eric Dumazet 已提交
2221
EXPORT_SYMBOL(tcp_close);
L
Linus Torvalds 已提交
2222 2223 2224

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

E
Eric Dumazet 已提交
2225
static inline bool tcp_need_reset(int state)
L
Linus Torvalds 已提交
2226 2227 2228 2229 2230 2231 2232 2233 2234
{
	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);
2235
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2236 2237 2238 2239 2240 2241 2242 2243 2244
	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) {
2245
		inet_csk_listen_stop(sk);
P
Pavel Emelyanov 已提交
2246 2247
	} else if (unlikely(tp->repair)) {
		sk->sk_err = ECONNABORTED;
L
Linus Torvalds 已提交
2248 2249 2250
	} 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
2251
		/* The last check adjusts for discrepancy of Linux wrt. RFC
L
Linus Torvalds 已提交
2252 2253 2254 2255 2256 2257 2258 2259 2260
		 * 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);
2261
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
2262
	__skb_queue_purge(&tp->out_of_order_queue);
C
Chris Leech 已提交
2263 2264 2265
#ifdef CONFIG_NET_DMA
	__skb_queue_purge(&sk->sk_async_wait_queue);
#endif
L
Linus Torvalds 已提交
2266

E
Eric Dumazet 已提交
2267
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
2268 2269 2270 2271 2272 2273 2274 2275 2276

	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;
2277
	icsk->icsk_backoff = 0;
L
Linus Torvalds 已提交
2278
	tp->snd_cwnd = 2;
2279
	icsk->icsk_probes_out = 0;
L
Linus Torvalds 已提交
2280
	tp->packets_out = 0;
I
Ilpo Järvinen 已提交
2281
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
2282
	tp->snd_cwnd_cnt = 0;
2283
	tp->bytes_acked = 0;
2284
	tp->window_clamp = 0;
2285
	tcp_set_ca_state(sk, TCP_CA_Open);
L
Linus Torvalds 已提交
2286
	tcp_clear_retrans(tp);
2287
	inet_csk_delack_init(sk);
2288
	tcp_init_send_head(sk);
2289
	memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
L
Linus Torvalds 已提交
2290 2291
	__sk_dst_reset(sk);

E
Eric Dumazet 已提交
2292
	WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
L
Linus Torvalds 已提交
2293 2294 2295 2296

	sk->sk_error_report(sk);
	return err;
}
E
Eric Dumazet 已提交
2297
EXPORT_SYMBOL(tcp_disconnect);
L
Linus Torvalds 已提交
2298

2299 2300 2301 2302 2303 2304 2305
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
2306
static inline bool tcp_can_repair_sock(const struct sock *sk)
P
Pavel Emelyanov 已提交
2307
{
2308
	return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
P
Pavel Emelyanov 已提交
2309 2310 2311
		((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}

2312 2313
static int tcp_repair_options_est(struct tcp_sock *tp,
		struct tcp_repair_opt __user *optbuf, unsigned int len)
2314
{
2315
	struct tcp_repair_opt opt;
2316

2317 2318
	while (len >= sizeof(opt)) {
		if (copy_from_user(&opt, optbuf, sizeof(opt)))
2319 2320 2321
			return -EFAULT;

		optbuf++;
2322
		len -= sizeof(opt);
2323

2324 2325 2326
		switch (opt.opt_code) {
		case TCPOPT_MSS:
			tp->rx_opt.mss_clamp = opt.opt_val;
2327
			break;
2328
		case TCPOPT_WINDOW:
2329 2330 2331 2332 2333 2334
			{
				u16 snd_wscale = opt.opt_val & 0xFFFF;
				u16 rcv_wscale = opt.opt_val >> 16;

				if (snd_wscale > 14 || rcv_wscale > 14)
					return -EFBIG;
2335

2336 2337 2338 2339
				tp->rx_opt.snd_wscale = snd_wscale;
				tp->rx_opt.rcv_wscale = rcv_wscale;
				tp->rx_opt.wscale_ok = 1;
			}
2340 2341
			break;
		case TCPOPT_SACK_PERM:
2342 2343 2344
			if (opt.opt_val != 0)
				return -EINVAL;

2345 2346 2347 2348 2349
			tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
			if (sysctl_tcp_fack)
				tcp_enable_fack(tp);
			break;
		case TCPOPT_TIMESTAMP:
2350 2351 2352
			if (opt.opt_val != 0)
				return -EINVAL;

2353 2354 2355 2356 2357 2358 2359 2360
			tp->rx_opt.tstamp_ok = 1;
			break;
		}
	}

	return 0;
}

L
Linus Torvalds 已提交
2361 2362 2363
/*
 *	Socket option code for TCP.
 */
2364
static int do_tcp_setsockopt(struct sock *sk, int level,
2365
		int optname, char __user *optval, unsigned int optlen)
L
Linus Torvalds 已提交
2366 2367
{
	struct tcp_sock *tp = tcp_sk(sk);
2368
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2369 2370 2371
	int val;
	int err = 0;

2372 2373 2374
	/* These are data/string values, all the others are ints */
	switch (optname) {
	case TCP_CONGESTION: {
2375 2376 2377 2378 2379 2380
		char name[TCP_CA_NAME_MAX];

		if (optlen < 1)
			return -EINVAL;

		val = strncpy_from_user(name, optval,
2381
					min_t(long, TCP_CA_NAME_MAX-1, optlen));
2382 2383 2384 2385 2386
		if (val < 0)
			return -EFAULT;
		name[val] = 0;

		lock_sock(sk);
2387
		err = tcp_set_congestion_control(sk, name);
2388 2389 2390
		release_sock(sk);
		return err;
	}
2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436
	case TCP_COOKIE_TRANSACTIONS: {
		struct tcp_cookie_transactions ctd;
		struct tcp_cookie_values *cvp = NULL;

		if (sizeof(ctd) > optlen)
			return -EINVAL;
		if (copy_from_user(&ctd, optval, sizeof(ctd)))
			return -EFAULT;

		if (ctd.tcpct_used > sizeof(ctd.tcpct_value) ||
		    ctd.tcpct_s_data_desired > TCP_MSS_DESIRED)
			return -EINVAL;

		if (ctd.tcpct_cookie_desired == 0) {
			/* default to global value */
		} else if ((0x1 & ctd.tcpct_cookie_desired) ||
			   ctd.tcpct_cookie_desired > TCP_COOKIE_MAX ||
			   ctd.tcpct_cookie_desired < TCP_COOKIE_MIN) {
			return -EINVAL;
		}

		if (TCP_COOKIE_OUT_NEVER & ctd.tcpct_flags) {
			/* Supercedes all other values */
			lock_sock(sk);
			if (tp->cookie_values != NULL) {
				kref_put(&tp->cookie_values->kref,
					 tcp_cookie_values_release);
				tp->cookie_values = NULL;
			}
			tp->rx_opt.cookie_in_always = 0; /* false */
			tp->rx_opt.cookie_out_never = 1; /* true */
			release_sock(sk);
			return err;
		}

		/* Allocate ancillary memory before locking.
		 */
		if (ctd.tcpct_used > 0 ||
		    (tp->cookie_values == NULL &&
		     (sysctl_tcp_cookie_size > 0 ||
		      ctd.tcpct_cookie_desired > 0 ||
		      ctd.tcpct_s_data_desired > 0))) {
			cvp = kzalloc(sizeof(*cvp) + ctd.tcpct_used,
				      GFP_KERNEL);
			if (cvp == NULL)
				return -ENOMEM;
2437 2438

			kref_init(&cvp->kref);
2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456
		}
		lock_sock(sk);
		tp->rx_opt.cookie_in_always =
			(TCP_COOKIE_IN_ALWAYS & ctd.tcpct_flags);
		tp->rx_opt.cookie_out_never = 0; /* false */

		if (tp->cookie_values != NULL) {
			if (cvp != NULL) {
				/* Changed values are recorded by a changed
				 * pointer, ensuring the cookie will differ,
				 * without separately hashing each value later.
				 */
				kref_put(&tp->cookie_values->kref,
					 tcp_cookie_values_release);
			} else {
				cvp = tp->cookie_values;
			}
		}
2457

2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470
		if (cvp != NULL) {
			cvp->cookie_desired = ctd.tcpct_cookie_desired;

			if (ctd.tcpct_used > 0) {
				memcpy(cvp->s_data_payload, ctd.tcpct_value,
				       ctd.tcpct_used);
				cvp->s_data_desired = ctd.tcpct_used;
				cvp->s_data_constant = 1; /* true */
			} else {
				/* No constant payload data. */
				cvp->s_data_desired = ctd.tcpct_s_data_desired;
				cvp->s_data_constant = 0; /* false */
			}
2471 2472

			tp->cookie_values = cvp;
2473 2474 2475 2476 2477 2478 2479
		}
		release_sock(sk);
		return err;
	}
	default:
		/* fallthru */
		break;
2480
	}
2481

L
Linus Torvalds 已提交
2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494
	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 */
2495
		if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
L
Linus Torvalds 已提交
2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512
			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;
2513
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2514 2515 2516 2517 2518
		} else {
			tp->nonagle &= ~TCP_NAGLE_OFF;
		}
		break;

A
Andreas Petlund 已提交
2519 2520 2521 2522 2523 2524 2525
	case TCP_THIN_LINEAR_TIMEOUTS:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_lto = val;
		break;

A
Andreas Petlund 已提交
2526 2527 2528 2529 2530
	case TCP_THIN_DUPACK:
		if (val < 0 || val > 1)
			err = -EINVAL;
		else
			tp->thin_dupack = val;
Y
Yuchung Cheng 已提交
2531 2532
			if (tp->thin_dupack)
				tcp_disable_early_retrans(tp);
A
Andreas Petlund 已提交
2533 2534
		break;

P
Pavel Emelyanov 已提交
2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570
	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;

2571 2572 2573 2574
	case TCP_REPAIR_OPTIONS:
		if (!tp->repair)
			err = -EINVAL;
		else if (sk->sk_state == TCP_ESTABLISHED)
2575 2576 2577
			err = tcp_repair_options_est(tp,
					(struct tcp_repair_opt __user *)optval,
					optlen);
2578 2579 2580 2581
		else
			err = -EPERM;
		break;

L
Linus Torvalds 已提交
2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599
	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;
2600
			tcp_push_pending_frames(sk);
L
Linus Torvalds 已提交
2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611
		}
		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))) {
2612
				u32 elapsed = keepalive_time_elapsed(tp);
L
Linus Torvalds 已提交
2613 2614 2615 2616
				if (tp->keepalive_time > elapsed)
					elapsed = tp->keepalive_time - elapsed;
				else
					elapsed = 0;
2617
				inet_csk_reset_keepalive_timer(sk, elapsed);
L
Linus Torvalds 已提交
2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636
			}
		}
		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
2637
			icsk->icsk_syn_retries = val;
L
Linus Torvalds 已提交
2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649
		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:
2650 2651 2652 2653
		/* 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
2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669
		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) {
2670
			icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2671
		} else {
2672
			icsk->icsk_ack.pingpong = 0;
L
Linus Torvalds 已提交
2673 2674
			if ((1 << sk->sk_state) &
			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
2675 2676
			    inet_csk_ack_scheduled(sk)) {
				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
2677
				tcp_cleanup_rbuf(sk, 1);
L
Linus Torvalds 已提交
2678
				if (!(val & 1))
2679
					icsk->icsk_ack.pingpong = 1;
L
Linus Torvalds 已提交
2680 2681 2682 2683
			}
		}
		break;

2684 2685 2686 2687 2688 2689
#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
2690 2691 2692 2693
	case TCP_USER_TIMEOUT:
		/* Cap the max timeout in ms TCP will retry/retrans
		 * before giving up and aborting (ETIMEDOUT) a connection.
		 */
2694 2695 2696 2697
		if (val < 0)
			err = -EINVAL;
		else
			icsk->icsk_user_timeout = msecs_to_jiffies(val);
2698
		break;
2699 2700 2701 2702 2703 2704 2705 2706

	case TCP_FASTOPEN:
		if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
		    TCPF_LISTEN)))
			err = fastopen_init_queue(sk, val);
		else
			err = -EINVAL;
		break;
L
Linus Torvalds 已提交
2707 2708 2709
	default:
		err = -ENOPROTOOPT;
		break;
2710 2711
	}

L
Linus Torvalds 已提交
2712 2713 2714 2715
	release_sock(sk);
	return err;
}

2716
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
2717
		   unsigned int optlen)
2718
{
2719
	const struct inet_connection_sock *icsk = inet_csk(sk);
2720 2721 2722 2723 2724 2725

	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
2726
EXPORT_SYMBOL(tcp_setsockopt);
2727 2728

#ifdef CONFIG_COMPAT
2729
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
2730
			  char __user *optval, unsigned int optlen)
2731
{
2732 2733 2734
	if (level != SOL_TCP)
		return inet_csk_compat_setsockopt(sk, level, optname,
						  optval, optlen);
2735 2736
	return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
2737
EXPORT_SYMBOL(compat_tcp_setsockopt);
2738 2739
#endif

L
Linus Torvalds 已提交
2740
/* Return information about state of tcp endpoint in API format. */
2741
void tcp_get_info(const struct sock *sk, struct tcp_info *info)
L
Linus Torvalds 已提交
2742
{
2743
	const struct tcp_sock *tp = tcp_sk(sk);
2744
	const struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2745 2746 2747 2748 2749
	u32 now = tcp_time_stamp;

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

	info->tcpi_state = sk->sk_state;
2750
	info->tcpi_ca_state = icsk->icsk_ca_state;
2751
	info->tcpi_retransmits = icsk->icsk_retransmits;
2752
	info->tcpi_probes = icsk->icsk_probes_out;
2753
	info->tcpi_backoff = icsk->icsk_backoff;
L
Linus Torvalds 已提交
2754 2755 2756

	if (tp->rx_opt.tstamp_ok)
		info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
2757
	if (tcp_is_sack(tp))
L
Linus Torvalds 已提交
2758 2759 2760 2761 2762
		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;
2763
	}
L
Linus Torvalds 已提交
2764

E
Eric Dumazet 已提交
2765
	if (tp->ecn_flags & TCP_ECN_OK)
L
Linus Torvalds 已提交
2766
		info->tcpi_options |= TCPI_OPT_ECN;
E
Eric Dumazet 已提交
2767 2768
	if (tp->ecn_flags & TCP_ECN_SEEN)
		info->tcpi_options |= TCPI_OPT_ECN_SEEN;
Y
Yuchung Cheng 已提交
2769 2770
	if (tp->syn_data_acked)
		info->tcpi_options |= TCPI_OPT_SYN_DATA;
L
Linus Torvalds 已提交
2771

2772 2773
	info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
2774
	info->tcpi_snd_mss = tp->mss_cache;
2775
	info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
L
Linus Torvalds 已提交
2776

2777 2778 2779 2780 2781 2782 2783
	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
2784 2785 2786 2787 2788
	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);
2789
	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
L
Linus Torvalds 已提交
2790 2791
	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);

2792
	info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
L
Linus Torvalds 已提交
2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807
	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);

2808 2809
static int do_tcp_getsockopt(struct sock *sk, int level,
		int optname, char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
2810
{
2811
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824
	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:
2825
		val = tp->mss_cache;
L
Linus Torvalds 已提交
2826 2827
		if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
			val = tp->rx_opt.user_mss;
2828 2829
		if (tp->repair)
			val = tp->rx_opt.mss_clamp;
L
Linus Torvalds 已提交
2830 2831 2832 2833 2834 2835 2836 2837
		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
2838
		val = keepalive_time_when(tp) / HZ;
L
Linus Torvalds 已提交
2839 2840
		break;
	case TCP_KEEPINTVL:
E
Eric Dumazet 已提交
2841
		val = keepalive_intvl_when(tp) / HZ;
L
Linus Torvalds 已提交
2842 2843
		break;
	case TCP_KEEPCNT:
E
Eric Dumazet 已提交
2844
		val = keepalive_probes(tp);
L
Linus Torvalds 已提交
2845 2846
		break;
	case TCP_SYNCNT:
2847
		val = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
L
Linus Torvalds 已提交
2848 2849 2850 2851 2852 2853 2854
		break;
	case TCP_LINGER2:
		val = tp->linger2;
		if (val >= 0)
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;
		break;
	case TCP_DEFER_ACCEPT:
2855 2856
		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
2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876
		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:
2877
		val = !icsk->icsk_ack.pingpong;
L
Linus Torvalds 已提交
2878
		break;
2879 2880 2881 2882 2883 2884 2885

	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;
2886
		if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
2887 2888
			return -EFAULT;
		return 0;
2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924

	case TCP_COOKIE_TRANSACTIONS: {
		struct tcp_cookie_transactions ctd;
		struct tcp_cookie_values *cvp = tp->cookie_values;

		if (get_user(len, optlen))
			return -EFAULT;
		if (len < sizeof(ctd))
			return -EINVAL;

		memset(&ctd, 0, sizeof(ctd));
		ctd.tcpct_flags = (tp->rx_opt.cookie_in_always ?
				   TCP_COOKIE_IN_ALWAYS : 0)
				| (tp->rx_opt.cookie_out_never ?
				   TCP_COOKIE_OUT_NEVER : 0);

		if (cvp != NULL) {
			ctd.tcpct_flags |= (cvp->s_data_in ?
					    TCP_S_DATA_IN : 0)
					 | (cvp->s_data_out ?
					    TCP_S_DATA_OUT : 0);

			ctd.tcpct_cookie_desired = cvp->cookie_desired;
			ctd.tcpct_s_data_desired = cvp->s_data_desired;

			memcpy(&ctd.tcpct_value[0], &cvp->cookie_pair[0],
			       cvp->cookie_pair_size);
			ctd.tcpct_used = cvp->cookie_pair_size;
		}

		if (put_user(sizeof(ctd), optlen))
			return -EFAULT;
		if (copy_to_user(optval, &ctd, sizeof(ctd)))
			return -EFAULT;
		return 0;
	}
2925 2926 2927 2928 2929 2930
	case TCP_THIN_LINEAR_TIMEOUTS:
		val = tp->thin_lto;
		break;
	case TCP_THIN_DUPACK:
		val = tp->thin_dupack;
		break;
2931

P
Pavel Emelyanov 已提交
2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951
	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;

2952 2953 2954
	case TCP_USER_TIMEOUT:
		val = jiffies_to_msecs(icsk->icsk_user_timeout);
		break;
L
Linus Torvalds 已提交
2955 2956
	default:
		return -ENOPROTOOPT;
2957
	}
L
Linus Torvalds 已提交
2958 2959 2960 2961 2962 2963 2964 2965

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

2966 2967 2968 2969 2970 2971 2972 2973 2974 2975
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
2976
EXPORT_SYMBOL(tcp_getsockopt);
2977 2978

#ifdef CONFIG_COMPAT
2979 2980
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
			  char __user *optval, int __user *optlen)
2981
{
2982 2983 2984
	if (level != SOL_TCP)
		return inet_csk_compat_getsockopt(sk, level, optname,
						  optval, optlen);
2985 2986
	return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
2987
EXPORT_SYMBOL(compat_tcp_getsockopt);
2988
#endif
L
Linus Torvalds 已提交
2989

2990 2991
struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
	netdev_features_t features)
H
Herbert Xu 已提交
2992 2993 2994
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	struct tcphdr *th;
2995
	unsigned int thlen;
H
Herbert Xu 已提交
2996
	unsigned int seq;
2997
	__be32 delta;
H
Herbert Xu 已提交
2998
	unsigned int oldlen;
2999
	unsigned int mss;
H
Herbert Xu 已提交
3000 3001 3002 3003

	if (!pskb_may_pull(skb, sizeof(*th)))
		goto out;

3004
	th = tcp_hdr(skb);
H
Herbert Xu 已提交
3005 3006 3007 3008 3009 3010 3011
	thlen = th->doff * 4;
	if (thlen < sizeof(*th))
		goto out;

	if (!pskb_may_pull(skb, thlen))
		goto out;

3012
	oldlen = (u16)~skb->len;
H
Herbert Xu 已提交
3013 3014
	__skb_pull(skb, thlen);

3015 3016 3017 3018
	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

3019 3020
	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */
3021 3022 3023 3024 3025 3026 3027 3028 3029 3030
		int type = skb_shinfo(skb)->gso_type;

		if (unlikely(type &
			     ~(SKB_GSO_TCPV4 |
			       SKB_GSO_DODGY |
			       SKB_GSO_TCP_ECN |
			       SKB_GSO_TCPV6 |
			       0) ||
			     !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
			goto out;
3031

3032
		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
3033 3034 3035 3036 3037

		segs = NULL;
		goto out;
	}

3038
	segs = skb_segment(skb, features);
H
Herbert Xu 已提交
3039 3040 3041
	if (IS_ERR(segs))
		goto out;

3042
	delta = htonl(oldlen + (thlen + mss));
H
Herbert Xu 已提交
3043 3044

	skb = segs;
3045
	th = tcp_hdr(skb);
H
Herbert Xu 已提交
3046 3047 3048 3049 3050
	seq = ntohl(th->seq);

	do {
		th->fin = th->psh = 0;

3051 3052
		th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
				       (__force u32)delta));
3053
		if (skb->ip_summed != CHECKSUM_PARTIAL)
3054 3055 3056
			th->check =
			     csum_fold(csum_partial(skb_transport_header(skb),
						    thlen, skb->csum));
H
Herbert Xu 已提交
3057

3058
		seq += mss;
H
Herbert Xu 已提交
3059
		skb = skb->next;
3060
		th = tcp_hdr(skb);
H
Herbert Xu 已提交
3061 3062 3063 3064 3065

		th->seq = htonl(seq);
		th->cwr = 0;
	} while (skb->next);

3066
	delta = htonl(oldlen + (skb->tail - skb->transport_header) +
3067
		      skb->data_len);
3068 3069
	th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
				(__force u32)delta));
3070
	if (skb->ip_summed != CHECKSUM_PARTIAL)
3071 3072
		th->check = csum_fold(csum_partial(skb_transport_header(skb),
						   thlen, skb->csum));
H
Herbert Xu 已提交
3073 3074 3075 3076

out:
	return segs;
}
H
Herbert Xu 已提交
3077
EXPORT_SYMBOL(tcp_tso_segment);
H
Herbert Xu 已提交
3078

H
Herbert Xu 已提交
3079 3080 3081 3082 3083 3084
struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
{
	struct sk_buff **pp = NULL;
	struct sk_buff *p;
	struct tcphdr *th;
	struct tcphdr *th2;
3085
	unsigned int len;
H
Herbert Xu 已提交
3086
	unsigned int thlen;
3087
	__be32 flags;
H
Herbert Xu 已提交
3088
	unsigned int mss = 1;
3089 3090
	unsigned int hlen;
	unsigned int off;
H
Herbert Xu 已提交
3091
	int flush = 1;
H
Herbert Xu 已提交
3092
	int i;
H
Herbert Xu 已提交
3093

3094 3095 3096 3097 3098 3099 3100 3101
	off = skb_gro_offset(skb);
	hlen = off + sizeof(*th);
	th = skb_gro_header_fast(skb, off);
	if (skb_gro_header_hard(skb, hlen)) {
		th = skb_gro_header_slow(skb, hlen, off);
		if (unlikely(!th))
			goto out;
	}
H
Herbert Xu 已提交
3102 3103 3104 3105 3106

	thlen = th->doff * 4;
	if (thlen < sizeof(*th))
		goto out;

3107 3108 3109 3110 3111 3112
	hlen = off + thlen;
	if (skb_gro_header_hard(skb, hlen)) {
		th = skb_gro_header_slow(skb, hlen, off);
		if (unlikely(!th))
			goto out;
	}
H
Herbert Xu 已提交
3113

3114
	skb_gro_pull(skb, thlen);
H
Herbert Xu 已提交
3115

3116
	len = skb_gro_len(skb);
H
Herbert Xu 已提交
3117 3118 3119 3120 3121 3122 3123 3124
	flags = tcp_flag_word(th);

	for (; (p = *head); head = &p->next) {
		if (!NAPI_GRO_CB(p)->same_flow)
			continue;

		th2 = tcp_hdr(p);

H
Herbert Xu 已提交
3125
		if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
H
Herbert Xu 已提交
3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}

		goto found;
	}

	goto out_check_final;

found:
	flush = NAPI_GRO_CB(p)->flush;
3137 3138 3139 3140
	flush |= (__force int)(flags & TCP_FLAG_CWR);
	flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
		  ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
	flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
3141
	for (i = sizeof(*th); i < thlen; i += 4)
H
Herbert Xu 已提交
3142 3143
		flush |= *(u32 *)((u8 *)th + i) ^
			 *(u32 *)((u8 *)th2 + i);
H
Herbert Xu 已提交
3144

H
Herbert Xu 已提交
3145
	mss = skb_shinfo(p)->gso_size;
H
Herbert Xu 已提交
3146

H
Herbert Xu 已提交
3147
	flush |= (len - 1) >= mss;
H
Herbert Xu 已提交
3148
	flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
H
Herbert Xu 已提交
3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159

	if (flush || skb_gro_receive(head, skb)) {
		mss = 1;
		goto out_check_final;
	}

	p = *head;
	th2 = tcp_hdr(p);
	tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);

out_check_final:
3160
	flush = len < mss;
3161 3162 3163
	flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
					TCP_FLAG_RST | TCP_FLAG_SYN |
					TCP_FLAG_FIN));
H
Herbert Xu 已提交
3164 3165 3166 3167 3168 3169 3170 3171 3172

	if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
		pp = head;

out:
	NAPI_GRO_CB(skb)->flush |= flush;

	return pp;
}
H
Herbert Xu 已提交
3173
EXPORT_SYMBOL(tcp_gro_receive);
H
Herbert Xu 已提交
3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189

int tcp_gro_complete(struct sk_buff *skb)
{
	struct tcphdr *th = tcp_hdr(skb);

	skb->csum_start = skb_transport_header(skb) - skb->head;
	skb->csum_offset = offsetof(struct tcphdr, check);
	skb->ip_summed = CHECKSUM_PARTIAL;

	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;

	if (th->cwr)
		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;

	return 0;
}
H
Herbert Xu 已提交
3190
EXPORT_SYMBOL(tcp_gro_complete);
H
Herbert Xu 已提交
3191

3192 3193
#ifdef CONFIG_TCP_MD5SIG
static unsigned long tcp_md5sig_users;
3194
static struct tcp_md5sig_pool __percpu *tcp_md5sig_pool;
3195 3196
static DEFINE_SPINLOCK(tcp_md5sig_pool_lock);

3197
static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool __percpu *pool)
3198 3199
{
	int cpu;
3200

3201
	for_each_possible_cpu(cpu) {
3202 3203 3204 3205
		struct tcp_md5sig_pool *p = per_cpu_ptr(pool, cpu);

		if (p->md5_desc.tfm)
			crypto_free_hash(p->md5_desc.tfm);
3206 3207 3208 3209 3210 3211
	}
	free_percpu(pool);
}

void tcp_free_md5sig_pool(void)
{
3212
	struct tcp_md5sig_pool __percpu *pool = NULL;
3213

3214
	spin_lock_bh(&tcp_md5sig_pool_lock);
3215 3216 3217 3218
	if (--tcp_md5sig_users == 0) {
		pool = tcp_md5sig_pool;
		tcp_md5sig_pool = NULL;
	}
3219
	spin_unlock_bh(&tcp_md5sig_pool_lock);
3220 3221 3222 3223 3224
	if (pool)
		__tcp_free_md5sig_pool(pool);
}
EXPORT_SYMBOL(tcp_free_md5sig_pool);

3225
static struct tcp_md5sig_pool __percpu *
3226
__tcp_alloc_md5sig_pool(struct sock *sk)
3227 3228
{
	int cpu;
3229
	struct tcp_md5sig_pool __percpu *pool;
3230

3231
	pool = alloc_percpu(struct tcp_md5sig_pool);
3232 3233 3234 3235 3236 3237 3238 3239 3240 3241
	if (!pool)
		return NULL;

	for_each_possible_cpu(cpu) {
		struct crypto_hash *hash;

		hash = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
		if (!hash || IS_ERR(hash))
			goto out_free;

3242
		per_cpu_ptr(pool, cpu)->md5_desc.tfm = hash;
3243 3244 3245 3246 3247 3248 3249
	}
	return pool;
out_free:
	__tcp_free_md5sig_pool(pool);
	return NULL;
}

3250
struct tcp_md5sig_pool __percpu *tcp_alloc_md5sig_pool(struct sock *sk)
3251
{
3252
	struct tcp_md5sig_pool __percpu *pool;
E
Eric Dumazet 已提交
3253
	bool alloc = false;
3254 3255

retry:
3256
	spin_lock_bh(&tcp_md5sig_pool_lock);
3257 3258
	pool = tcp_md5sig_pool;
	if (tcp_md5sig_users++ == 0) {
E
Eric Dumazet 已提交
3259
		alloc = true;
3260
		spin_unlock_bh(&tcp_md5sig_pool_lock);
3261 3262
	} else if (!pool) {
		tcp_md5sig_users--;
3263
		spin_unlock_bh(&tcp_md5sig_pool_lock);
3264 3265 3266
		cpu_relax();
		goto retry;
	} else
3267
		spin_unlock_bh(&tcp_md5sig_pool_lock);
3268 3269 3270

	if (alloc) {
		/* we cannot hold spinlock here because this may sleep. */
3271
		struct tcp_md5sig_pool __percpu *p;
3272 3273

		p = __tcp_alloc_md5sig_pool(sk);
3274
		spin_lock_bh(&tcp_md5sig_pool_lock);
3275 3276
		if (!p) {
			tcp_md5sig_users--;
3277
			spin_unlock_bh(&tcp_md5sig_pool_lock);
3278 3279 3280 3281 3282
			return NULL;
		}
		pool = tcp_md5sig_pool;
		if (pool) {
			/* oops, it has already been assigned. */
3283
			spin_unlock_bh(&tcp_md5sig_pool_lock);
3284 3285 3286
			__tcp_free_md5sig_pool(p);
		} else {
			tcp_md5sig_pool = pool = p;
3287
			spin_unlock_bh(&tcp_md5sig_pool_lock);
3288 3289 3290 3291 3292 3293
		}
	}
	return pool;
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);

E
Eric Dumazet 已提交
3294 3295 3296 3297 3298 3299 3300 3301 3302

/**
 *	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)
3303
{
3304
	struct tcp_md5sig_pool __percpu *p;
E
Eric Dumazet 已提交
3305 3306 3307 3308

	local_bh_disable();

	spin_lock(&tcp_md5sig_pool_lock);
3309 3310 3311
	p = tcp_md5sig_pool;
	if (p)
		tcp_md5sig_users++;
E
Eric Dumazet 已提交
3312 3313 3314
	spin_unlock(&tcp_md5sig_pool_lock);

	if (p)
3315
		return this_cpu_ptr(p);
3316

E
Eric Dumazet 已提交
3317 3318 3319 3320
	local_bh_enable();
	return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
3321

E
Eric Dumazet 已提交
3322
void tcp_put_md5sig_pool(void)
3323
{
E
Eric Dumazet 已提交
3324
	local_bh_enable();
3325
	tcp_free_md5sig_pool();
3326
}
E
Eric Dumazet 已提交
3327
EXPORT_SYMBOL(tcp_put_md5sig_pool);
3328 3329

int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
3330
			const struct tcphdr *th)
3331 3332
{
	struct scatterlist sg;
3333
	struct tcphdr hdr;
3334 3335
	int err;

3336 3337 3338 3339
	/* We are not allowed to change tcphdr, make a local copy */
	memcpy(&hdr, th, sizeof(hdr));
	hdr.check = 0;

3340
	/* options aren't included in the hash */
3341 3342
	sg_init_one(&sg, &hdr, sizeof(hdr));
	err = crypto_hash_update(&hp->md5_desc, &sg, sizeof(hdr));
3343 3344 3345 3346 3347
	return err;
}
EXPORT_SYMBOL(tcp_md5_hash_header);

int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
3348
			  const struct sk_buff *skb, unsigned int header_len)
3349 3350 3351 3352
{
	struct scatterlist sg;
	const struct tcphdr *tp = tcp_hdr(skb);
	struct hash_desc *desc = &hp->md5_desc;
3353 3354 3355
	unsigned int i;
	const unsigned int head_data_len = skb_headlen(skb) > header_len ?
					   skb_headlen(skb) - header_len : 0;
3356
	const struct skb_shared_info *shi = skb_shinfo(skb);
3357
	struct sk_buff *frag_iter;
3358 3359 3360 3361 3362 3363 3364 3365 3366

	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];
3367
		struct page *page = skb_frag_page(f);
E
Eric Dumazet 已提交
3368 3369
		sg_set_page(&sg, page, skb_frag_size(f), f->page_offset);
		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
3370 3371 3372
			return 1;
	}

3373 3374 3375 3376
	skb_walk_frags(skb, frag_iter)
		if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
			return 1;

3377 3378 3379 3380
	return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);

3381
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
3382 3383 3384 3385 3386 3387 3388 3389
{
	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);

3390 3391
#endif

3392
/* Each Responder maintains up to two secret values concurrently for
3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519
 * efficient secret rollover.  Each secret value has 4 states:
 *
 * Generating.  (tcp_secret_generating != tcp_secret_primary)
 *    Generates new Responder-Cookies, but not yet used for primary
 *    verification.  This is a short-term state, typically lasting only
 *    one round trip time (RTT).
 *
 * Primary.  (tcp_secret_generating == tcp_secret_primary)
 *    Used both for generation and primary verification.
 *
 * Retiring.  (tcp_secret_retiring != tcp_secret_secondary)
 *    Used for verification, until the first failure that can be
 *    verified by the newer Generating secret.  At that time, this
 *    cookie's state is changed to Secondary, and the Generating
 *    cookie's state is changed to Primary.  This is a short-term state,
 *    typically lasting only one round trip time (RTT).
 *
 * Secondary.  (tcp_secret_retiring == tcp_secret_secondary)
 *    Used for secondary verification, after primary verification
 *    failures.  This state lasts no more than twice the Maximum Segment
 *    Lifetime (2MSL).  Then, the secret is discarded.
 */
struct tcp_cookie_secret {
	/* The secret is divided into two parts.  The digest part is the
	 * equivalent of previously hashing a secret and saving the state,
	 * and serves as an initialization vector (IV).  The message part
	 * serves as the trailing secret.
	 */
	u32				secrets[COOKIE_WORKSPACE_WORDS];
	unsigned long			expires;
};

#define TCP_SECRET_1MSL (HZ * TCP_PAWS_MSL)
#define TCP_SECRET_2MSL (HZ * TCP_PAWS_MSL * 2)
#define TCP_SECRET_LIFE (HZ * 600)

static struct tcp_cookie_secret tcp_secret_one;
static struct tcp_cookie_secret tcp_secret_two;

/* Essentially a circular list, without dynamic allocation. */
static struct tcp_cookie_secret *tcp_secret_generating;
static struct tcp_cookie_secret *tcp_secret_primary;
static struct tcp_cookie_secret *tcp_secret_retiring;
static struct tcp_cookie_secret *tcp_secret_secondary;

static DEFINE_SPINLOCK(tcp_secret_locker);

/* Select a pseudo-random word in the cookie workspace.
 */
static inline u32 tcp_cookie_work(const u32 *ws, const int n)
{
	return ws[COOKIE_DIGEST_WORDS + ((COOKIE_MESSAGE_WORDS-1) & ws[n])];
}

/* Fill bakery[COOKIE_WORKSPACE_WORDS] with generator, updating as needed.
 * Called in softirq context.
 * Returns: 0 for success.
 */
int tcp_cookie_generator(u32 *bakery)
{
	unsigned long jiffy = jiffies;

	if (unlikely(time_after_eq(jiffy, tcp_secret_generating->expires))) {
		spin_lock_bh(&tcp_secret_locker);
		if (!time_after_eq(jiffy, tcp_secret_generating->expires)) {
			/* refreshed by another */
			memcpy(bakery,
			       &tcp_secret_generating->secrets[0],
			       COOKIE_WORKSPACE_WORDS);
		} else {
			/* still needs refreshing */
			get_random_bytes(bakery, COOKIE_WORKSPACE_WORDS);

			/* The first time, paranoia assumes that the
			 * randomization function isn't as strong.  But,
			 * this secret initialization is delayed until
			 * the last possible moment (packet arrival).
			 * Although that time is observable, it is
			 * unpredictably variable.  Mash in the most
			 * volatile clock bits available, and expire the
			 * secret extra quickly.
			 */
			if (unlikely(tcp_secret_primary->expires ==
				     tcp_secret_secondary->expires)) {
				struct timespec tv;

				getnstimeofday(&tv);
				bakery[COOKIE_DIGEST_WORDS+0] ^=
					(u32)tv.tv_nsec;

				tcp_secret_secondary->expires = jiffy
					+ TCP_SECRET_1MSL
					+ (0x0f & tcp_cookie_work(bakery, 0));
			} else {
				tcp_secret_secondary->expires = jiffy
					+ TCP_SECRET_LIFE
					+ (0xff & tcp_cookie_work(bakery, 1));
				tcp_secret_primary->expires = jiffy
					+ TCP_SECRET_2MSL
					+ (0x1f & tcp_cookie_work(bakery, 2));
			}
			memcpy(&tcp_secret_secondary->secrets[0],
			       bakery, COOKIE_WORKSPACE_WORDS);

			rcu_assign_pointer(tcp_secret_generating,
					   tcp_secret_secondary);
			rcu_assign_pointer(tcp_secret_retiring,
					   tcp_secret_primary);
			/*
			 * Neither call_rcu() nor synchronize_rcu() needed.
			 * Retiring data is not freed.  It is replaced after
			 * further (locked) pointer updates, and a quiet time
			 * (minimum 1MSL, maximum LIFE - 2MSL).
			 */
		}
		spin_unlock_bh(&tcp_secret_locker);
	} else {
		rcu_read_lock_bh();
		memcpy(bakery,
		       &rcu_dereference(tcp_secret_generating)->secrets[0],
		       COOKIE_WORKSPACE_WORDS);
		rcu_read_unlock_bh();
	}
	return 0;
}
EXPORT_SYMBOL(tcp_cookie_generator);

A
Andi Kleen 已提交
3520 3521
void tcp_done(struct sock *sk)
{
3522 3523
	struct request_sock *req = tcp_sk(sk)->fastopen_rsk;

3524
	if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
3525
		TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
A
Andi Kleen 已提交
3526 3527 3528

	tcp_set_state(sk, TCP_CLOSE);
	tcp_clear_xmit_timers(sk);
3529 3530
	if (req != NULL)
		reqsk_fastopen_remove(sk, req, false);
A
Andi Kleen 已提交
3531 3532 3533 3534 3535 3536 3537 3538 3539 3540

	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);

3541
extern struct tcp_congestion_ops tcp_reno;
L
Linus Torvalds 已提交
3542 3543 3544 3545

static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
3546 3547
	ssize_t ret;

L
Linus Torvalds 已提交
3548 3549
	if (!str)
		return 0;
3550 3551 3552 3553 3554

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

L
Linus Torvalds 已提交
3555 3556 3557 3558
	return 1;
}
__setup("thash_entries=", set_thash_entries);

3559 3560 3561 3562 3563 3564 3565 3566 3567
void tcp_init_mem(struct net *net)
{
	unsigned long limit = nr_free_buffer_pages() / 8;
	limit = max(limit, 128UL);
	net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
	net->ipv4.sysctl_tcp_mem[1] = limit;
	net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
}

L
Linus Torvalds 已提交
3568 3569 3570
void __init tcp_init(void)
{
	struct sk_buff *skb = NULL;
3571
	unsigned long limit;
3572
	int max_rshare, max_wshare, cnt;
3573
	unsigned int i;
3574
	unsigned long jiffy = jiffies;
L
Linus Torvalds 已提交
3575

3576
	BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
L
Linus Torvalds 已提交
3577

3578
	percpu_counter_init(&tcp_sockets_allocated, 0);
3579
	percpu_counter_init(&tcp_orphan_count, 0);
3580 3581 3582
	tcp_hashinfo.bind_bucket_cachep =
		kmem_cache_create("tcp_bind_bucket",
				  sizeof(struct inet_bind_bucket), 0,
3583
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3584 3585 3586 3587 3588 3589

	/* Size and allocate the main established and bind bucket
	 * hash tables.
	 *
	 * The methodology is similar to that of the buffer cache.
	 */
3590
	tcp_hashinfo.ehash =
L
Linus Torvalds 已提交
3591
		alloc_large_system_hash("TCP established",
3592
					sizeof(struct inet_ehash_bucket),
L
Linus Torvalds 已提交
3593
					thash_entries,
E
Eric Dumazet 已提交
3594
					17, /* one slot per 128 KB of memory */
3595
					0,
L
Linus Torvalds 已提交
3596
					NULL,
3597
					&tcp_hashinfo.ehash_mask,
3598
					0,
3599
					thash_entries ? 0 : 512 * 1024);
3600
	for (i = 0; i <= tcp_hashinfo.ehash_mask; i++) {
3601 3602
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
L
Linus Torvalds 已提交
3603
	}
3604 3605
	if (inet_ehash_locks_alloc(&tcp_hashinfo))
		panic("TCP: failed to alloc ehash_locks");
3606
	tcp_hashinfo.bhash =
L
Linus Torvalds 已提交
3607
		alloc_large_system_hash("TCP bind",
3608
					sizeof(struct inet_bind_hashbucket),
3609
					tcp_hashinfo.ehash_mask + 1,
E
Eric Dumazet 已提交
3610
					17, /* one slot per 128 KB of memory */
3611
					0,
3612
					&tcp_hashinfo.bhash_size,
L
Linus Torvalds 已提交
3613
					NULL,
3614
					0,
L
Linus Torvalds 已提交
3615
					64 * 1024);
3616
	tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
3617 3618 3619
	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
3620 3621
	}

E
Eric Dumazet 已提交
3622 3623 3624 3625 3626 3627

	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
3628

3629
	tcp_init_mem(&init_net);
3630
	/* Set per-socket limits to no more than 1/128 the pressure threshold */
E
Eric Dumazet 已提交
3631
	limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
3632 3633
	max_wshare = min(4UL*1024*1024, limit);
	max_rshare = min(6UL*1024*1024, limit);
3634

3635
	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
3636
	sysctl_tcp_wmem[1] = 16*1024;
3637
	sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
3638

3639
	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
3640
	sysctl_tcp_rmem[1] = 87380;
3641
	sysctl_tcp_rmem[2] = max(87380, max_rshare);
L
Linus Torvalds 已提交
3642

3643
	pr_info("Hash tables configured (established %u bind %u)\n",
J
Joe Perches 已提交
3644
		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
3645

3646 3647
	tcp_metrics_init();

3648
	tcp_register_congestion_control(&tcp_reno);
3649 3650 3651 3652 3653 3654 3655 3656 3657

	memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));
	memset(&tcp_secret_two.secrets[0], 0, sizeof(tcp_secret_two.secrets));
	tcp_secret_one.expires = jiffy; /* past due */
	tcp_secret_two.expires = jiffy; /* past due */
	tcp_secret_generating = &tcp_secret_one;
	tcp_secret_primary = &tcp_secret_one;
	tcp_secret_retiring = &tcp_secret_two;
	tcp_secret_secondary = &tcp_secret_two;
E
Eric Dumazet 已提交
3658
	tcp_tasklet_init();
L
Linus Torvalds 已提交
3659
}