kern/138666: [multicast] [panic] not working multicast through igmpproxy

[Bruce Simpson]

Andriy Syrovenko wrote:
> I have switched to 8-STABLE. Kernel does not seem to crash anymore,
> however IGMP still does not work. tcpdump complains that outgoing IGMP
> report and leave packets have incorrect checksum- it is always 0.
> Though I'm not sure weather it is IGMP checksum or IP checksum that is
> incorrect.
>   

This just sounds like a fairly normal artefact of tcpdump/bpf with 
checksum offload, as I get the exactly same thing on my desktop w/ re(4).

You need to confirm the checksums at the wire to be sure, or disable 
rxcsum/txcsum:
    # ifconfig re0 -txcsum -rxcsum

Nothing has changed in the behaviour of the code which computes IGMP 
checksums; it does not depend on the outer IP header, and isn't touched 
by IP checksum offload, unless your network card (or its driver) is 
doing something it shouldn't be doing.

Perhaps Florian can shed some light on your IGMP issue? igmpproxy only 
understands IGMPv2, afaik.

thanks,
BMS