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Date:      Fri, 7 Jan 2011 06:17:47 -0500 (EST)
From:      Daniel Eischen <deischen@freebsd.org>
To:        "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net>
Cc:        freebsd-current@freebsd.org
Subject:   Re: UDP checksum broken, -head and releng_8
Message-ID:  <Pine.GSO.4.64.1101070613200.20933@sea.ntplx.net>
In-Reply-To: <20110107103837.E14966@maildrop.int.zabbadoz.net>
References:  <Pine.GSO.4.64.1101070412140.19838@sea.ntplx.net> <20110107103837.E14966@maildrop.int.zabbadoz.net>

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On Fri, 7 Jan 2011, Bjoern A. Zeeb wrote:

> On Fri, 7 Jan 2011, Daniel Eischen wrote:
>
>> When sending multicast packets to a socket that is _not_
>> bound to the multicast address, this generates bad UDP
>> checksums.  This use to work and was broke sometime between
>> the middle of October and late December as far as I can
>> tell.
>
> My very best guess would be: r215110

It doesn't look very harmful, but I'll try backing it out.

> Otherwise the usual questions apply though I am almost certain you got
> that right:
>
> - dumps taken on the receiver side not the sender as

Yes, dumps were taken on both receiving Solaris 10
and FreeBSD hosts.

> - NIC offload capabilities might confuse tcpdump and you might
>  want to turn them off and test as well w/o them

Disabling checksum offloading makes no difference, and the
problem occurs on all interfaces I have tested (sis, bfe,
wpi).

-- 
DE



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