On Mon, Apr 28, 2014 at 03:57:58PM -0700, Jarno Rajahalme wrote: > > On Mar 20, 2014, at 10:05 AM, Ben Pfaff <b...@nicira.com> wrote: > > > On Fri, Mar 14, 2014 at 04:19:52PM +0900, Simon Horman wrote: > >> When creating a flow in the datapath as the result of an upcall > >> the match itself is the match supplied in the upcall while > >> the mask of the match, if supplied, is generated based on the > >> flow and mask composed during action translation. > >> > >> In the case of, for example a UDP packet, the match will include > >> of L2, L3 and L4 fields. However, if the flow is cleared in > >> flow_push_mpls() then the mask that is synthesised from it will > >> not include L3 and L4 fields. This seems incorrect and the kernel > >> datapath complains about this mismatch. > >> > >> Signed-off-by: Simon Horman <ho...@verge.net.au> > > > > The goal of clearing the fields is to ensure that later flow tables > > can't match on fields that aren't visible anymore. That's important for > > accurate OpenFlow implementation, so I'd rather not change it. On the > > other hand, I see the point you're making, but I don't immediately > > understand why it happens that way. After all, I can change fields with > > OpenFlow actions and the datapath flows work out OK, why doesn't this > > work out OK too? Do you understand the reason? > > As the flow?s dl_type is changed to an MPLS type, later non-MPLS rules > will not match on the modified flow. AFAIK, you can match on L3/L4 > fields only by also matching on the corresponding dl_type as a > prerequisite, no?
Yes, that's true. > If this holds, I?d rather not clear the fields so we can properly do a > set IPv4 action followed by an MPLS push action. Currently the the > MPLS action clears the flow values at the translation time set in the > preceding action, so that at the commit time the values intended for > set IPv4 action are lost. Are you sure? compose_mpls_push_action() call commit_odp_actions() to avoid this very problem. Assuming I'm right about that, at this point what I really want is an example of a situation that's broken in the current code and not broken with this patch applied, so that I can understand exactly what we're getting at here. Thanks, Ben. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
