[ 69/85] ipv4: Dont create nh exeption when the device mtu is smaller than the reported pmtu

[Greg Kroah-Hartman]

3.6-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>

[ Upstream commit 7f92d334ba19a0d8e96f8f8f092219553367d921 ]

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@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv4/route.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -909,6 +909,9 @@ static void __ip_rt_update_pmtu(struct r
 	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;
 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/