route: Use ipv4_mtu instead of raw rt_pmtu
The commit 3cdaa5be9e81a914e633a6be7b7d2ef75b528562 ("ipv4: Don't
increase PMTU with Datagram Too Big message") broke PMTU in cases
where the rt_pmtu value has expired but is smaller than the new
PMTU value.
This obsolete rt_pmtu then prevents the new PMTU value from being
installed.
Fixes: 3cdaa5be9e81 ("ipv4: Don't increase PMTU with Datagram Too Big message")
Reported-by: Gerd v. Egidy <gerd.von.egidy@intra2net.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a78540f..bff62fc 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -962,10 +962,7 @@
if (dst_metric_locked(dst, RTAX_MTU))
return;
- if (dst->dev->mtu < mtu)
- return;
-
- if (rt->rt_pmtu && rt->rt_pmtu < mtu)
+ if (ipv4_mtu(dst) < mtu)
return;
if (mtu < ip_rt_min_pmtu)