Subject: Re: [patch for 2.6.27? 4/5] forcedeth: fix checksum flag

From: Jeff Garzik <[email-masked]>
Date: Wed, 27 Aug 2008 05:57:23 -0400

[email-masked] wrote:
> From: Ayaz Abdulla <[email-masked]>
> 
> Fix the checksum feature advertised in device flags.  The hardware support
> TCP/UDP over IPv4 and TCP/UDP over IPv6 (without IPv6 extension headers). 
> However, the kernel feature flags do not distinguish IPv6 with/without
> extension headers.
> 
> Therefore, the driver needs to use NETIF_F_IP_CSUM instead of
> NETIF_F_HW_CSUM since the latter includes all IPv6 packets.
> 
> A future patch can be created to check for extension headers and perform
> software checksum calculation.
> 
> Signed-off-by: Ayaz Abdulla <[email-masked]>
> Cc: Jeff Garzik <[email-masked]>
> Cc: Manfred Spraul <[email-masked]
> Cc: <[email-masked]>		[2.6.25.x, 2.6.26.x]
> Signed-off-by: Andrew Morton <[email-masked]>

applied, although for future reference, read the top of 
include/linux/skbuff.h, most notably:

  *          NOTE: Even if device supports only some protocols, but
  *          is able to produce some skb->csum, it MUST use COMPLETE,
  *          not UNNECESSARY.