UDP checksum broken, -head and releng_8

Daniel Eischen deischen at freebsd.org
Fri Jan 7 11:42:03 UTC 2011

On Fri, 7 Jan 2011, Daniel Eischen wrote:

> 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.

Backing this out seems to fix it.  I'll have to test it
more after I get some sleep ;-)

>> 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).


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