[ovs-dev] [PATCH] datapath: Add basic MPLS support to kernel

Simon Horman horms at verge.net.au
Fri Oct 5 00:00:48 UTC 2012


On Thu, Oct 04, 2012 at 08:52:52AM -0700, Jesse Gross wrote:
> On Thu, Oct 4, 2012 at 1:58 AM, Simon Horman <horms at verge.net.au> wrote:
> > On Wed, Oct 03, 2012 at 12:17:16PM -0700, Jesse Gross wrote:
> >> From: Leo Alterman <lalterman at nicira.com>
> >>
> >> Allow datapath to recognize and extract MPLS labels into flow keys
> >> and execute actions which push, pop, and set labels on packets.
> >>
> >> Signed-off-by: Leo Alterman <lalterman at nicira.com>
> >
> >
> > Hi,
> >
> > As a method of reviewing this I've been reworking Ravi's user-space
> > datapath and non-datapath code to match up with this kernel datapath
> > implementation.
> >
> > That part seems to be working out well, though I'd like to clean
> > up my efforts a little before posting.
> >
> >
> > One thing that am curious about is if OVS_ACTION_ATTR_SET_MPLS is needed.
> >
> > I believe that setting the label value (the top 20 bits), tc and bos can be
> > handled using set-field actions for OF1.2+ (OXM) and load actions for NXM.
> >
> > And I believe that manipulation of the TTL can be handled by TTL-specific
> > actions that are not part of this datapath implementation but presumably
> > will be added later.
> >
> > I believe that the above would be is in keeping with the OF1.2 and OF1.3
> > specifications wile also providing an NX extension mechanism.
> 
> I'm not sure that I really understand the question.
> OVS_ACTION_ATTR_SET_MPLS would be the mechanism that set-field, etc.
> use to actually implement their behavior at the kernel level.

Thanks, that answers the question that I should have asked.

> I don't want to add any TTL-specific actions to the kernel such
> decrement, copy-in/out, etc.  When we do support that it should be
> using set and some form of resubmit if necessary (as we do for IP).
> However, the cases requiring resubmit are more complex, which is why
> they're not implemented for the time being.

Understood, that is fine by me in all respects.



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