Bug 203289 - Kernel will drop any IGMPv3 "Group-Specific Queries" if the source IP is 0.0.0.0
Summary: Kernel will drop any IGMPv3 "Group-Specific Queries" if the source IP is 0.0.0.0
Status: NEW
Alias: None
Product: Networking
Classification: Unclassified
Component: IPV4 (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Stephen Hemminger
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-04-12 13:53 UTC by Mal
Modified: 2019-04-16 11:33 UTC (History)
0 users

See Also:
Kernel Version: < 5
Subsystem:
Regression: No
Bisected commit-id:

Attachments
Example of an IGMP GSQ dropped by kernel (100 bytes, application/vnd.tcpdump.pcap)
2019-04-16 11:33 UTC, Mal 		Details
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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
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