From b8291bbfa392773abe54aed10e6c5553d8cde8b3 Mon Sep 17 00:00:00 2001
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Wed, 16 Jan 2013 20:58:10 +0000
Subject: ipv4: Don't update the pmtu on mtu locked routes

[ Upstream commit fa1e492aa3cbafba9f8fc6d05e5b08a3091daf4a ]

Routes with locked mtu should not use learned pmtu informations,
so do not update the pmtu on these routes.

Reported-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/route.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'net')

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 11d28e3ff0d7..0660d6f1a1cb 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -912,6 +912,9 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 	struct dst_entry *dst = &rt->dst;
 	struct fib_result res;
 
+	if (dst_metric_locked(dst, RTAX_MTU))
+		return;
+
 	if (dst->dev->mtu < mtu)
 		return;
 
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