[ovs-dev] [PATCH 2/2] OXM: Allow masking of IPv6 Flow Label

Simon Horman horms at verge.net.au
Fri Jul 13 00:44:31 UTC 2012


On Thu, Jul 12, 2012 at 08:58:20AM -0700, Ben Pfaff wrote:
> On Thu, Jul 12, 2012 at 09:12:10AM +0900, Simon Horman wrote:
> > One thing that I do have a problem with is the correct treatment of the CFI
> > bit in the value and mask when decoded from an OXMi VLAN_VID match.  So far
> > I have come up with four possible solutions.
> > 
> > 1. Require it to always be set except in the case of OFPVID12_NONE
> > 2. Require it to always be clear except in the case of OFPVID12_PRESENT
> >    - I believe that this is how things need to be handled internally
> > 3. Ignore the CFI bit except in the case of OFPVID12_NONE and OFPVID12_PRESENT.
> > 4. Honour the CFI bit.
> 
> You raise a good question.  I think that option #4 is most flexible.  It
> would allow a controller, for example, to match bits 0-11 against
> all-zeros and wildcard bit 12 (the CFI bit), which would presumably
> match both packets without a VLAN tag and packets with a VLAN tag for
> VLAN 0.

Ok, I will see about making that so.
I think it is also the easiest to implement in conjunction with the current
VLAN TCI handling code.

> 
> I didn't understand your comment on option #2, but I didn't think about
> it for too long.

I now think that my point isn't entirely true.



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