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From: ebiederm@xmission.com (Eric W. Biederman)
To: David Miller <davem@davemloft.net>
Cc: <netdev@vger.kernel.org>
Subject: [PATCH net-next 4/6] mpls: Correct the ttl decrement.
Date: Sat, 07 Mar 2015 16:23:23 -0600	[thread overview]
Message-ID: <87a8zo4fc4.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <874mpw5u3x.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Sat, 07 Mar 2015 16:18:58 -0600")


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>
---
 net/mpls/af_mpls.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 5c99e3fc1b72..e120074157de 100644
--- 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;
 
-- 
2.2.1

  parent reply	other threads:[~2015-03-07 22:27 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-07 22:18 [PATCH net-next 0/6] mpls: Minor fixes and cleanups Eric W. Biederman
2015-03-07 22:19 ` [PATCH net-next 1/6] mpls: Fix the kzalloc argument order in mpls_rt_alloc Eric W. Biederman
2015-03-07 22:21 ` [PATCH net-next 2/6] mpls: Cleanup the rcu usage in the code Eric W. Biederman
2015-03-07 22:22 ` [PATCH net-next 3/6] mpls: Better error code for unsupported option Eric W. Biederman
2015-03-07 22:23 ` Eric W. Biederman [this message]
2015-03-07 22:24 ` [PATCH net-next 5/6] mpls: Fix the openvswitch select of NET_MPLS_GSO Eric W. Biederman
2015-03-08  9:09   ` Simon Horman
2015-03-07 22:25 ` [PATCH net-next 6/6] neigh: Use neigh table index for neigh_packet_xmit Eric W. Biederman
2015-03-08 23:33 ` [PATCH net-next 0/6] mpls: Minor fixes and cleanups David Miller

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