Hi Greg,
Please consider backporting the following bridge multicast fix series
to all applicable stable kernels:
726fa7da2d8c ("ipv4: igmp: get rid of IGMPV3_{QQIC,MRC} and simplify
calculation")
12cfb4ecc471 ("ipv6: mld: rename mldv2_mrc() and add mldv2_qqi()")
95bfd196f0dc ("ipv4: igmp: encode multicast exponential fields")
e51560f4220a ("ipv6: mld: encode multicast exponential fields")
529dbe762de0 ("selftests: net: bridge: add MRC and QQIC field encoding tests")
This series was merged via: db314398f618 ("net: bridge: mcast: support
exponential field encoding")
History: The multicast stack currently supports decoding of IGMPv3 and
MLDv2 exponential timer field encodings, but lacks the corresponding
encoding logic when generating multicast query packets. As a result,
query intervals and response codes exceeding the linear encoding range
can be transmitted incorrectly. This can cause multicast queriers and
listeners to interpret different timing values, resulting in protocol
interoperability issues, membership timeouts, and premature multicast
group expiration.
Testing: The series adds the missing encoding support for both IGMPv3
and MLDv2 and includes selftests that validate the behavior.
I backported the series to v6.6.123.2 and verified the accompanying
selftests. The selftests fail on the unpatched kernel and pass after
applying the series, demonstrating both the bug and the effectiveness
of the fix.
Given that this is a protocol correctness issue affecting multicast
query generation, please consider backporting the complete series to
all applicable stable kernels.
Thanks,
Ujjal
