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  1. Fast Datapath Product
  2. FDP-2117

Packet too big and IPv4 multicast

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      Please mark each item below with ( / ) if completed or ( x ) if incomplete:

      ( ) The acceptance criteria defined below are met.

      Given an IPv4 packet larger than the MTU that is destined to a broadcast or multicast address,

      When an OVN logical router processes this packet,

      Then it drops the packet locally without sending it to ovn-controller to generate an ICMP "Packet Too Big" response.

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

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

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      Please mark each item below with ( / ) if completed or ( x ) if incomplete: ( ) The acceptance criteria defined below are met. Given an IPv4 packet larger than the MTU that is destined to a broadcast or multicast address, When an OVN logical router processes this packet, Then it drops the packet locally without sending it to ovn-controller to generate an ICMP "Packet Too Big" response. ( ) The epics work is available in a downstream build (nightly/Async or other) ( ) All cards under the epic have been moved to Done
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    • ssg_networking

      RFC1812 (4.3.2.7) mandate that "An ICMP error message MUST NOT be sent as the result of receiving... a packet destined to an IP broadcast or IP multicast address."

      As of now, OVN checks packet len and, if too big, sends the packet to ovn-controller to generate an ICMP error, even for broadcast/multicast packets.

      As a side effect of fixing this issue, the action in the generated flow for those multicast/broadcast packets will be much smaller, becoming something similar to

      check_pkt_len(size=1514,gt(drop),le(action))

      instead of

      check_pkt_len(size=1514,gt(userspace(pid=4269294687,controller(reason=1,dont_send=0,continuation=0,recirc_id=1121,rule_cookie=0xb42a1191,controller_id=0,max_len=65535))),le(action)).

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