Date: Tue, 08 Dec 2009 09:40:00 +0000 From: Bruce Simpson <bms@incunabulum.net> To: Andriy Syrovenko <andriys@gmail.com> Cc: freebsd-net@freebsd.org, flo@smeets.im Subject: Re: kern/138666: [multicast] [panic] not working multicast through igmpproxy Message-ID: <4B1E1EF0.8040503@incunabulum.net> In-Reply-To: <3e2b8dd90912080114x31d962acqf2c8a360e7b5a83d@mail.gmail.com> References: <200912071020.nB7AK77I023054@freefall.freebsd.org> <4B1CDEE5.6080507@incunabulum.net> <3e2b8dd90912070305t6ffc08a6gf7acd8890d028854@mail.gmail.com> <4B1D07C3.6090005@incunabulum.net> <3e2b8dd90912080114x31d962acqf2c8a360e7b5a83d@mail.gmail.com>
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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
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