Bug 203289

Summary:	Kernel will drop any IGMPv3 "Group-Specific Queries" if the source IP is 0.0.0.0
Product:	Networking	Reporter:	Mal (mal.hubert)
Component:	IPV4	Assignee:	Stephen Hemminger (stephen)
Status:	NEW ---
Severity:	normal
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	< 5	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	Example of an IGMP GSQ dropped by kernel

Description Mal 2019-04-12 13:53:58 UTC

Kernel drops any IGMPv3 Membership Queries of type 'Group-Specific' if the source IP is 0.0.0.0.

Membership Queries of type 'General Query' are not dropped.

This behaviour is not documented as a desired behaviour anywhere in the igmp rfcs.

Comment 1 Mal 2019-04-12 14:42:09 UTC

In fact:

RFC 3376 says that an IGMP report with a 0.0.0.0 source can be used by the system that is yet to acquire an IP address and it must be accepted by the router receiving it.

RFC 4541 also mentions a special case where the switch does IGMP query proxying and sends a query with a source IP address of 0.0.0.0. It further states that such query messages must not be rejected because of the source IP address of 0.0.0.0.

Comment 2 Mal 2019-04-16 11:33:50 UTC

Created attachment 282347 [details]
Example of an IGMP GSQ dropped by kernel