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  1. Fast Datapath Product
  2. FDP-1568

Do not call check_pkt_larger for ARP packets

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    • Do not call check_pkt_larger for ARP packets
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      Please mark each item below with ( / ) if completed or ( x ) if incomplete:

      ( ) The acceptance criteria defined below are met.

      Given a logical topology with IPv4/IPv6 and ARP traffic,

      When OVN compiles logical flows to OpenFlow,

      Then no flows involving ARP should use the check_pkt_len() or set the REGBIT_PKT_LARGER register.


      ( ) The epics work is available in a downstream build (nightly/Async or other)


      ( ) All cards under the epic have been moved to Done

      Show
      Please mark each item below with ( / ) if completed or ( x ) if incomplete: ( ) The acceptance criteria defined below are met. Given a logical topology with IPv4/IPv6 and ARP traffic, When OVN compiles logical flows to OpenFlow, Then no flows involving ARP should use the check_pkt_len() or set the REGBIT_PKT_LARGER register. ( ) The epics work is available in a downstream build (nightly/Async or other) ( ) All cards under the epic have been moved to Done
    • rhel-9
    • rhel-net-ovn
    • 91% To Do, 0% In Progress, 9% Done
    • ssg_networking

      This epic tracks all the effort needed to deliver the solution related to the bug described below.

       Problem Description: Clearly explain the issue.

      FDP-1538 identified some OVS issues when using flows such as

      meter(),pop_vlan,check_pkt_len(size=1456,gt(meter(),set(eth),set(arp)2),le(meter(),set(eth),set(arp),2).

      Such flows are somehow unexpected as both branches of gt() are the same.

      OVN is responsible of building the openflows which get translated by OVS in such flows. 

      OVN should not create those un-optimal flows.

       Impact Assessment: Describe the severity and impact (e.g., network down,availability of a workaround, etc.).

      Low as it does not seem that fixing this would workaround all cases hit by FDP-1538.

       Software Versions: Specify the exact versions in use (e.g.,openvswitch3.1-3.1.0-147.el8fdp).

      Reproduced on main.

        Issue Type: Indicate whether this is a new issue or a regression (if a regression, state the last known working version).

      Not a regression.

       Reproducibility: Confirm if the issue can be reproduced consistently. If not, describe how often it occurs.

      Can be reproduced consistently.

       Reproduction Steps: Provide detailed steps or scripts to replicate the issue.

      No easy steps, but using db from FDP-1538 (using gateway_mtu) and simulating arp_request towards arp_tpa=10.25.21.245

       Expected Behavior: Describe what should happen under normal circumstances.

      • No check_pkt_len flows for ARP packets
      • Flows with check_pkt_len should have different actions for both paths.

       Observed Behavior: Explain what actually happens.

      Un-optimal flow created. Such flow then hits FDP-1538 issue.

       Troubleshooting Actions: Outline the steps taken to diagnose or resolve the issue so far.

      Flows checking REGBIT_PKT_LARGER bit are matching on ip4 or ip6. Hence, there is no need to set this bit for ARP (it is not checked anyhow).

       Logs: If you collected logs please provide them (e.g. sos report, /var/log/openvswitch/* , testpmd console)

              ovnteam@redhat.com OVN Team
              xsimonar@redhat.com Xavier Simonart
              Jianlin Shi Jianlin Shi
              OVN
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                Created:
                Updated: