[ovs-dev] [PATCH 6/8] ofproto-dpif-xlate: Do not add more MPLS LSEs than the datapath can handle

[Simon Horman]

On Thu, Jan 16, 2014 at 04:35:24PM -0800, Ben Pfaff wrote:
> On Fri, Jan 17, 2014 at 09:28:29AM +0900, Simon Horman wrote:
> > On Thu, Jan 16, 2014 at 04:10:43PM -0800, Ben Pfaff wrote:
> > > On Wed, Jan 15, 2014 at 04:13:23PM +0900, Simon Horman wrote:
> > > > This is an proposed enhancement to
> > > > "Implement OpenFlow support for MPLS, for up to 3 labels."
> > > > 
> > > > This makes the conservative assumption that the datapath should
> > > > not be asked to apply MPLS push actions such that the resulting
> > > > packet will have an MPLS label stack depth greater than the
> > > > datapath can accept in a match.
> > > > 
> > > > In future it may be possible to use recirculation to handle
> > > > such cases.
> > > > 
> > > > Signed-off-by: Simon Horman <horms at verge.net.au>
> > > 
> > > I think that we can handle these in userspace with SLOW_ACTION, so I
> > > changed this patch to just the following:
> > 
> > Does this approach work in the case where
> > n < ctx->xbridge->max_mpls_depth && n >= ARRAY_SIZE(flow->mpls_lse) ?
> 
> I don't understand why we'd ever bother with max_mpls_depth >
> ARRAY_SIZE(flow->mpls_lse).  I don't think the probing code, as
> written, would ever report such a maximum depth.

Good point.