[ovs-dev] [PATCH 4/4] tests: Add MPLS push on MPLS test.

Simon Horman horms at verge.net.au
Wed Feb 12 01:38:16 UTC 2014


On Tue, Feb 11, 2014 at 05:06:53PM -0800, Joe Stringer wrote:
> On 11 February 2014 16:53, Simon Horman <horms at verge.net.au> wrote:
> >
> > I believe that the reason you are seeing a VLAN tagged packet come out is
> > that you are sending a VLAN tagged packet in. This is because of
> > eth_type(0x8100), which I believe should be eth_type(0x8847).
> 
> 
> I see, that makes sense.
> 
> 
> > The packet dump below starts with "40 45" after the MPLS label stack, but
> > I believe it and all the data after it should be zero. This is because the
> > input packet only has an L2 header followed by an MPLS LSE. This will be
> > padded to 64 bytes with zeroes by OVS when it is received.
> >
> 
> Right, this is the type of thing that I knew was wrong.
> 
> >
> > In the course of looking at this I realised there is a bug which can be
> > exercised by a variant of this patch. The bug is that push_mpls() only
> > updates the ethertype if the input packet is not MPLS.  But this does not
> > take into account that there are two MPLS ethertypes and an MPLS push may
> > change a packet from one to another.
> >
> > I will post a patch that fixes that problem and adds a test-case for it.
> >
> 
> Glad that the patch had the intended effect, even if it was trivially
> wrong. Thanks for picking this up.

Thanks, it seems to have worked out quite nicely :)




More information about the dev mailing list