ipv4: Don't increase PMTU with Datagram Too Big message.

RFC 1191 said, "a host MUST not increase its estimate of the Path MTU in response to the contents of a Datagram Too Big message." Signed-off-by: Li Wei <[email protected]> Signed-off-by: David S. Miller <[email protected]>
laijs · Jan 29, 2015 · 3cdaa5b · 3cdaa5b
1 parent a1a0b55
commit 3cdaa5b
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
@@ -966,6 +966,9 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 	if (dst->dev->mtu < mtu)
 		return;
 
+	if (rt->rt_pmtu && rt->rt_pmtu < mtu)
+		return;
+
 	if (mtu < ip_rt_min_pmtu)
 		mtu = ip_rt_min_pmtu;