Bug 1935180 - [4.7z] IGMP/MLD packets being dropped
Summary: [4.7z] IGMP/MLD packets being dropped
Alias: None
Product: OpenShift Container Platform
Classification: Red Hat
Component: Networking
Version: 4.7
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
: 4.7.z
Assignee: Victor Pickard
QA Contact: Weibin Liang
Depends On: 1935155
TreeView+ depends on / blocked
Reported: 2021-03-04 13:52 UTC by Tim Rozet
Modified: 2021-04-05 13:56 UTC (History)
3 users (show)

Fixed In Version:
Doc Type: No Doc Update
Doc Text:
Clone Of: 1935155
Last Closed: 2021-04-05 13:55:43 UTC
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Github openshift ovn-kubernetes pull 468 0 None open Bug 1935180: Backport Fix mcast querier 2021-03-16 14:51:04 UTC
Red Hat Product Errata RHSA-2021:1005 0 None None None 2021-04-05 13:56:03 UTC

Description Tim Rozet 2021-03-04 13:52:33 UTC
+++ This bug was initially created as a clone of Bug #1935155 +++

Description of problem:

Ovn-k8s multicast allow acls should allow IGMP/MLD pkts regardless of source address.

IPv6 MLD packets are being dropped.

Version-Release number of selected component (if applicable):

How reproducible:


Steps to Reproduce

There is a detailed slack conversation regarding this issue here:


I have an ipv4 single stack cluster with ovn-kubernetes cni.
I see that after few minutes ~5, the join (igmp) request is expired.
I'm following the steps in the openshift "enable multicast" guide.

If I run

oc exec mlistener -i -t -- \
    socat UDP4-RECVFROM:30102,ip-add-membership=$POD_IP,fork EXEC:hostname

then I run

oc exec msender -i -t -- \
    /bin/bash -c "echo | socat STDIO UDP4-DATAGRAM:,range=$CIDR,ip-multicast-ttl=64"

It works as expected.

But if I run the send request again after ~5 min, it doesn't work. I need the "listener" to re-join the multicast group to make it work again.

Actual results:

Expected results:

Additional info:

Comment 2 Weibin Liang 2021-03-25 16:31:41 UTC
Tested and verified in 4.7.0-0.nightly-2021-03-25-091845

Comment 5 errata-xmlrpc 2021-04-05 13:55:43 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: OpenShift Container Platform 4.7.5 security and bug fix update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


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