/*
 *	X.25 Packet Layer release 002
 *
 *	This is ALPHA test software. This code may break your machine,
 *	randomly fail to work with new releases, misbehave and/or generally
 *	screw up. It might even work.
 *
 *	This code REQUIRES 2.1.15 or higher
 *
 *	This module:
 *		This module 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.
 *
 *	History
 *	X.25 001	Jonathan Naylor	Started coding.
 *	X.25 002	Jonathan Naylor	New timer architecture.
 *					Centralised disconnection processing.
 */

#include <linux/errno.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/x25.h>

static void x25_heartbeat_expiry(unsigned long);
static void x25_timer_expiry(unsigned long);

void x25_init_timers(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	setup_timer(&x25->timer, x25_timer_expiry, (unsigned long)sk);

	/* initialized by sock_init_data */
	sk->sk_timer.data     = (unsigned long)sk;
	sk->sk_timer.function = &x25_heartbeat_expiry;
}

void x25_start_heartbeat(struct sock *sk)
{
	mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
}

void x25_stop_heartbeat(struct sock *sk)
{
	del_timer(&sk->sk_timer);
}

void x25_start_t2timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t2);
}

void x25_start_t21timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t21);
}

void x25_start_t22timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t22);
}

void x25_start_t23timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	mod_timer(&x25->timer, jiffies + x25->t23);
}

void x25_stop_timer(struct sock *sk)
{
	del_timer(&x25_sk(sk)->timer);
}

unsigned long x25_display_timer(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	if (!timer_pending(&x25->timer))
		return 0;

	return x25->timer.expires - jiffies;
}

static void x25_heartbeat_expiry(unsigned long param)
{
	struct sock *sk = (struct sock *)param;

	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
		goto restart_heartbeat;

	switch (x25_sk(sk)->state) {

		case X25_STATE_0:
			/*
			 * Magic here: If we listen() and a new link dies
			 * before it is accepted() it isn't 'dead' so doesn't
			 * get removed.
			 */
			if (sock_flag(sk, SOCK_DESTROY) ||
			    (sk->sk_state == TCP_LISTEN &&
			     sock_flag(sk, SOCK_DEAD))) {
				bh_unlock_sock(sk);
				x25_destroy_socket_from_timer(sk);
				return;
			}
			break;

		case X25_STATE_3:
			/*
			 * Check for the state of the receive buffer.
			 */
			x25_check_rbuf(sk);
			break;
	}
restart_heartbeat:
	x25_start_heartbeat(sk);
	bh_unlock_sock(sk);
}

/*
 *	Timer has expired, it may have been T2, T21, T22, or T23. We can tell
 *	by the state machine state.
 */
static inline void x25_do_timer_expiry(struct sock * sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	switch (x25->state) {

		case X25_STATE_3:	/* T2 */
			if (x25->condition & X25_COND_ACK_PENDING) {
				x25->condition &= ~X25_COND_ACK_PENDING;
				x25_enquiry_response(sk);
			}
			break;

		case X25_STATE_1:	/* T21 */
		case X25_STATE_4:	/* T22 */
			x25_write_internal(sk, X25_CLEAR_REQUEST);
			x25->state = X25_STATE_2;
			x25_start_t23timer(sk);
			break;

		case X25_STATE_2:	/* T23 */
			x25_disconnect(sk, ETIMEDOUT, 0, 0);
			break;
	}
}

static void x25_timer_expiry(unsigned long param)
{
	struct sock *sk = (struct sock *)param;

	bh_lock_sock(sk);
	if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
		if (x25_sk(sk)->state == X25_STATE_3)
			x25_start_t2timer(sk);
	} else
		x25_do_timer_expiry(sk);
	bh_unlock_sock(sk);
}
d></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>David S. Miller &lt;davem@davemloft.net&gt;</td><td class='right'>2017-02-07 13:07:56 -0500</td></tr>
<tr><th>committer</th><td>David S. Miller &lt;davem@davemloft.net&gt;</td><td class='right'>2017-02-07 13:07:56 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/core?id=29ba6e7400a317725bdfb86a725d1824447dbcd7'>29ba6e7400a317725bdfb86a725d1824447dbcd7</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/core?id=29ba6e7400a317725bdfb86a725d1824447dbcd7'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=29ba6e7400a317725bdfb86a725d1824447dbcd7'>b009850c5a2e7c633a94eeacb71a25f91b4b64f0</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/core?id=29ba6e7400a317725bdfb86a725d1824447dbcd7'>net/core</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/core?id=b08d46b01e995dd7b653b22d35bd1d958d6ee9b4'>b08d46b01e995dd7b653b22d35bd1d958d6ee9b4</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/core?id=29ba6e7400a317725bdfb86a725d1824447dbcd7&amp;id2=b08d46b01e995dd7b653b22d35bd1d958d6ee9b4'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/core?id=51ce8bd4d17a761e1a90a34a1b5c9b762cce7553'>51ce8bd4d17a761e1a90a34a1b5c9b762cce7553</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/core?id=29ba6e7400a317725bdfb86a725d1824447dbcd7&amp;id2=51ce8bd4d17a761e1a90a34a1b5c9b762cce7553'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge branch 'replace-dst_confirm'</div><div class='commit-msg'>Julian Anastasov says:

====================
net: dst_confirm replacement

	This patchset addresses the problem of neighbour
confirmation where received replies from one nexthop
can cause confirmation of different nexthop when using
the same dst. Thanks to YueHaibing &lt;yuehaibing@huawei.com&gt;
for tracking the dst-&gt;pending_confirm problem.

	Sockets can obtain cached output route. Such
routes can be to known nexthop (rt_gateway=IP) or to be
used simultaneously for different nexthop IPs by different
subnet prefixes (nh-&gt;nh_scope = RT_SCOPE_HOST, rt_gateway=0).

	At first look, there are more problems:

- dst_confirm() sets flag on dst and not on dst-&gt;path,
as result, indication is lost when XFRM is used

- DNAT can change the nexthop, so the really used nexthop is
not confirmed

	So, the following solution is to avoid using
dst-&gt;pending_confirm.

	The current dst_confirm() usage is as follows:

Protocols confirming dst on received packets:
- TCP (1 dst per socket)
- SCTP (1 dst per transport)
- CXGB*

Protocols supporting sendmsg with MSG_CONFIRM [ | MSG_PROBE ] to
confirm neighbour:
- UDP IPv4/IPv6
- ICMPv4 PING
- RAW IPv4/IPv6
- L2TP/IPv6

MSG_CONFIRM for other purposes (fix not needed):
- CAN

Sending without locking the socket:
- UDP (when no cork)
- RAW (when hdrincl=1)

Redirects from old to new GW:
- rt6_do_redirect

	The patchset includes the following changes:

1. sock: add sk_dst_pending_confirm flag

- used only by TCP with patch 4 to remember the received
indication in sk-&gt;sk_dst_pending_confirm

2. net: add dst_pending_confirm flag to skbuff

- skb-&gt;dst_pending_confirm will be used by all protocols
in following patches, via skb_{set,get}_dst_pending_confirm

3. sctp: add dst_pending_confirm flag

- SCTP uses per-transport dsts and can not use
sk-&gt;sk_dst_pending_confirm like TCP

4. tcp: replace dst_confirm with sk_dst_confirm

5. net: add confirm_neigh method to dst_ops

- IPv4 and IPv6 provision for slow neigh lookups for MSG_PROBE users.
I decided to use neigh lookup only for this case because on
MSG_PROBE the skb may pass MTU checks but it does not reach
the neigh confirmation code. This patch will be used from patch 6.

- xfrm_confirm_neigh: we use the last tunnel address, if present.
When there are only transports, the original dest address is used.

6. net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP

- dst_confirm conversion for UDP, RAW, ICMP and L2TP/IPv6

- these protocols use MSG_CONFIRM propagated by ip*_append_data
to skb-&gt;dst_pending_confirm. sk-&gt;sk_dst_pending_confirm is not
used because some sending paths do not lock the socket. For
MSG_PROBE we use the slow lookup (dst_confirm_neigh).

- there are also 2 cases that need the slow lookup:
__ip6_rt_update_pmtu and rt6_do_redirect. I hope
&amp;ipv6_hdr(skb)-&gt;saddr is the correct nexthop address to use here.

7. net: pending_confirm is not used anymore

- I failed to understand the CXGB* code, I see dst_confirm()
calls but I'm not sure dst_neigh_output() was called. For now
I just removed the dst-&gt;pending_confirm flag and left all
dst_confirm() calls there. Any better idea?

- Now may be old function neigh_output() should be restored
instead of dst_neigh_output?
====================

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=29ba6e7400a317725bdfb86a725d1824447dbcd7'>Diffstat</a> (limited to 'net/core')</div><table summary='diffstat' class='diffstat'><tr><td class='mode'>-rw-r--r--</td><td class='upd'><a href='/cgit.cgi/linux/net-next.git/diff/net/core/dst.c?id=29ba6e7400a317725bdfb86a725d1824447dbcd7'>net/core/dst.c</a></td><td class='right'>1</td><td class='graph'><table summary='file diffstat' width='2%'><tr><td class='add' style='width: 0.0%;'/><td class='rem' style='width: 50.0%;'/><td class='none' style='width: 50.0%;'/></tr></table></td></tr>
<tr><td class='mode'>-rw-r--r--</td><td class='upd'><a href='/cgit.cgi/linux/net-next.git/diff/net/core/sock.c?id=29ba6e7400a317725bdfb86a725d1824447dbcd7'>net/core/sock.c</a></td><td class='right'>2</td><td class='graph'><table summary='file diffstat' width='2%'><tr><td class='add' style='width: 100.0%;'/><td class='rem' style='width: 0.0%;'/><td class='none' style='width: 0.0%;'/></tr></table></td></tr>
</table><div class='diffstat-summary'>2 files changed, 2 insertions, 1 deletions</div><table summary='diff' class='diff'><tr><td><div class='head'>diff --git a/net/core/dst.c b/net/core/dst.c