Need Info on Checksum Offloading

Need Info on Checksum Offloading

[harish.vasudeva]

Hi All,

 Could any1 pls direct me wherein i could find some documentation about implementing checksum offloading for my ethernet LAN driver?

thanx
HARISH V

Re: Need Info on Checksum Offloading

[Jeff Garzik]

harish.vasudeva@amd.com wrote:
> 
> Hi All,
> 
>  Could any1 pls direct me wherein i could find some documentation about implementing checksum offloading for my ethernet LAN driver?


There is not good documentation.  Feel free to ask me questions, I am
the Linux network driver maintainer.

First, search the source code in linux/drivers/net/* for
NETIF_F_IP_CSUM, NETIF_F_HW_CSUM, skb->csum, and nr_frags.

Can I expect an ethernet driver submitted to me, soon?

	Jeff

-- 
Jeff Garzik      | Only so many songs can be sung
Building 1024    | with two lips, two lungs, and one tongue.
MandrakeSoft     |         - nomeansno

Re: Need Info on Checksum Offloading

[Andi Kleen]

harish.vasudeva@amd.com writes:

> Hi All,
> 
>  Could any1 pls direct me wherein i could find some documentation about implementing checksum offloading for my ethernet LAN driver?

include/linux/skbuff.h has a big fat comment describing checksums handling.
Just read it.

For RX checksums you just set ip_summed of the incoming skb 
to CHECKSUM_UNNCESSARY (you did a complete check of the checksum;
not recommended as you're unlikely to support all weird protocols) or 
CHECKSUM_HW (you put a checksum of the TCP/UDP data area minus pseudo header
and ip header into skb->csum) or CHECKSUM_NONE for sw checksum.

-Andi