On Thu, Nov 05, 2020 at 12:39:38PM +0000, ythomas1....@orange.com wrote: > I’m currently working on OVN to add MPLS logical fields (such as > 'mpls_label', 'mpls_bos') to support BGP/MPLS technology. > > As indicated in 'mf_field' struct in meta-flow.h, most OVS meta-flow > fields have n_bytes * 8 == n_bits size but there are few exceptions > such as 'mpls_label', 'mpls_bos', etc… > > In OVN case, when calling 'mf_mask_subfield' method from meta-flow.c, > for example for 'mpls_label' OVS meta-flow field which has 20 useful > bits over 32 bits, the 'mask' value parsed in OVN is set to 0xffff00ff > (which seems correct).
OVN doesn't use that function much. I see one use in constrain_match(). I don't understand where 0xffff00ff comes from. The mask should not be discontiguous like that. > The problem is that in 'mf_set' method, 'mpls_label' OVS meta-flow > field is supposed to only have a NULL, all-1-bits or all-0-bits 'mask' > value to be set, as shown below: [...] > However, as mentioned in 'mf_set' method comment, “The caller is > responsible for ensuring that 'match' meets 'mf''s prerequisites”. > > So, since the 'mpls_label' OVS meta-flow field is indicated as not > maskable in meta-flow.h, shouldn't OVN ensure that 'mask' is set to > NULL when calling 'mf_mask_subfield' ? The mask isn't a prerequisite. The prerequisite for mpls_label is that the flow is an MPLS flow, that is, it has an MPLS ethertype. See mf_are_prereqs_ok(). _______________________________________________ discuss mailing list disc...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
