[3.11.y.z extended stable] Patch "l2tp: take PMTU from tunnel UDP socket" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    l2tp: take PMTU from tunnel UDP socket

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 6298c30c2e0f3c934aa3558c4f7d56f1c99c9c00 Mon Sep 17 00:00:00 2001
From: Dmitry Petukhov <dmgenp at gmail.com>
Date: Wed, 9 Apr 2014 02:23:20 +0600
Subject: l2tp: take PMTU from tunnel UDP socket

commit f34c4a35d87949fbb0e0f31eba3c054e9f8199ba upstream.

When l2tp driver tries to get PMTU for the tunnel destination, it uses
the pointer to struct sock that represents PPPoX socket, while it
should use the pointer that represents UDP socket of the tunnel.

Signed-off-by: Dmitry Petukhov <dmgenp at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/l2tp/l2tp_ppp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 44441c0c5037..9a0e5874e73e 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -754,9 +754,9 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	session->deref = pppol2tp_session_sock_put;

 	/* If PMTU discovery was enabled, use the MTU that was discovered */
-	dst = sk_dst_get(sk);
+	dst = sk_dst_get(tunnel->sock);
 	if (dst != NULL) {
-		u32 pmtu = dst_mtu(__sk_dst_get(sk));
+		u32 pmtu = dst_mtu(__sk_dst_get(tunnel->sock));
 		if (pmtu != 0)
 			session->mtu = session->mru = pmtu -
 				PPPOL2TP_HEADER_OVERHEAD;
--
1.9.1