ipv4: Don't create nh exeption when the device mtu is smaller than the reported pmtu
When a local tool like tracepath tries to send packets bigger than
the device mtu, we create a nh exeption and set the pmtu to device
mtu. The device mtu does not expire, so check if the device mtu is
smaller than the reported pmtu and don't crerate a nh exeption in
that case.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 90ba835..741df67a 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -909,6 +909,9 @@
struct dst_entry *dst = &rt->dst;
struct fib_result res;
+ if (dst->dev->mtu < mtu)
+ return;
+
if (mtu < ip_rt_min_pmtu)
mtu = ip_rt_min_pmtu;