Problem Description:

The fix for FDP-906 broke hashing and comparison of MAC binding entries for the timestamp update purposes, because entries in the hash map have sbrec pointers set, while data entries created from OpenFlow statistics dump do not have this information. Since UUID is part of the hash and also required for comparison in mac_binding_data_equals, it is actually impossible for ovn-controller to find the entries using OpenFlow stats nodes in order to refresh them.

 Impact Assessment:

This is causing active MAC binding entries to expire, leading to packets being sent to ovn-controller for ARP resolution and being dropped on CoPP meter.

 Software Versions:

ovn24.03-24.03.4-9.el9fdp

  Issue Type:

Regression, worked in FDP 24.G with OVN 24.03.

 Reproducibility:

100%

 Reproduction Steps:

Create a setup with a GW router where MAC binding entries are being learned. Continuously send traffic to a directly reachable destination for which MAC binding entry will be created. See the entry expire after MAC binding aging threshold despite the traffic flowing.

 Expected Behavior:

Active MAC binding entries should not expire.

 Observed Behavior:

MAC binding entry for an active triffic expires after the aging threshold time.