From: Li Wei <l...@cn.fujitsu.com>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 3cdaa5be9e81a914e633a6be7b7d2ef75b528562 upstream.
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 <l...@cn.fujitsu.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Jiri Slaby <jsl...@suse.cz>
---
net/ipv4/route.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index bd5f3461d1ce..fe0c761a8fce 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -988,6 +988,9 @@ 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;
--
2.7.0
