[ovs-dev] [PATCH] ofproto-dpif: Treat zero MPLS post-decrement TTL as invalid.

[Ben Pfaff]

On Thu, Mar 07, 2013 at 06:13:06PM +0100, Simon Horman wrote:
> On Wed, Mar 06, 2013 at 02:57:59PM -0800, Ben Pfaff wrote:
> > RFC 3443 says that an outgoing MPLS TTL of zero is invalid, so we must send
> > packets that have such a TTL post-decrement to the controller rather than
> > allowing them to continue through the OpenFlow tables.
> > 
> > Here is the text from RFC 3443 that implies this behavior:
> > 
> >    oTTL: This is the TTL value used as the outgoing TTL value (see
> >    section 3.5 for exception).  It is always (iTTL - 1) unless otherwise
> >    stated.
> > 
> >    oTTL Check: Check if oTTL is greater than 0.  If the oTTL Check is
> >    false, then the packet is not forwarded.  Note that the oTTL check is
> >    performed only if any outgoing TTL (either IP or MPLS) is set to oTTL
> >    (see section 3.5 for exception).
> > 
> > That is, the output TTL is one less than the input TTL, and a packet with
> > an output TTL of 0 must not be forwarded.
> > 
> > CC: Bruce Davie <bsd at nicira.com>
> > Signed-off-by: Ben Pfaff <blp at nicira.com>
> 
> No objections here.
> 
> Reviewed-by: Simon Horman <horms at verge.net.au>

Thanks.  I applied this to master.