From 3cdaa5be9e81a914e633a6be7b7d2ef75b528562 Mon Sep 17 00:00:00 2001 From: Li Wei Date: Thu, 29 Jan 2015 16:09:03 +0800 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/ipv4/route.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index d58dd0ec3e53..52e1f2bf0ca2 100644 --- 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; -- 2.11.0