offloading ip checksum calculation to the NIC

[Yar Tikhiy]

On Fri, Feb 03, 2006 at 03:07:03PM +0300, Gleb Smirnoff wrote:
> 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

FWIW, the details of hardware-assisted checksumming are also
documented on the mbuf(9) and ifnet(9) manpages.

-- 
Yar