mpls: Correct the ttl decrement.

According to RFC3032 section 2.4.2  packets with an outgoing
ttl of 0 MUST NOT be forwarded.  According to section 2.4.1
an outgoing TTL of 0 comes from an incomming TTL <= 1.

Therefore any packets that is received with a ttl <= 1 should
not have it's ttl decremented and forwarded.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 5c99e3fc1b72fd676844e9b4559a17e46defa0d2..e120074157deb95faf989f0fc70de28ceddee67b 100644 (file)
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -162,7 +162,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
        skb_forward_csum(skb);
 
        /* Verify ttl is valid */
-       if (dec.ttl <= 2)
+       if (dec.ttl <= 1)
                goto drop;
        dec.ttl -= 1;