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Date: Fri, 3 Feb 2006 15:07:03 +0300
From: Gleb Smirnoff <glebius@FreeBSD.org>
To: kamal kc <kamal_ckk@yahoo.com>
Message-ID: <20060203120703.GT60276@FreeBSD.org>
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Cc: freebsd-net@FreeBSD.org
Subject: Re: offloading ip checksum calculation to the NIC
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On Fri, Feb 03, 2006 at 02:30:54AM -0800, kamal kc wrote:
k> so what do i need to do if i don't want to calculate 
k> the ip checksum myself ?
k> 
k> right now i am taking off packet from the kernel 
k> and modifying some of the data content, and 
k> outputting to the IFQ_HANDOFF myself. and i 
k> am calculating the checksum myself. 
k> 
k> i guess if xl would support the 
k> hardware checksumming i could use that 
k> feature. 
k> 
k> i am just a beginner and i am not getting
k> the clear picture. 

If interfaces has enabled capabilities for checksum offloading, then
the kernel skips checksum calculation.

See http://people.freebsd.org/~jlemon/csum.txt

-- 
Totus tuus, Glebius.
GLEBIUS-RIPN GLEB-RIPE