netdev - Re: [PATCH] net: Do not include padding in TCP GRO checksum

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Date:	Thu, 14 Nov 2013 21:34:14 -0800
From:	Alexander Duyck <alexander.duyck@...il.com>
To:	David Miller <davem@...emloft.net>, alexander.h.duyck@...el.com
CC:	netdev@...r.kernel.org, edumazet@...gle.com,
	herbert@...dor.apana.org
Subject: Re: [PATCH] net: Do not include padding in TCP GRO checksum

On 11/14/2013 08:08 PM, David Miller wrote:
> From: Alexander Duyck <alexander.h.duyck@...el.com>
> Date: Thu, 14 Nov 2013 17:18:18 -0800
> 
>> I haven't had a chance to test this much yet and I am not that familiar
> 
> As Eric mentioned, unless you tested on big endian, chances are you
> didn't test this at all. :-)
> 

Actually I had tested it very breifly, but with Rx checksum offloads
still enabled.

> You're accessing the IPv4/IPv6 length fields without converting it
> to CPU endian.

Yeah, I realized that after I hit the BUG_ON in skb_checksum.

I'll be submitting a v2 in the morning with some tested code.  The only
difficult part is that I don't have any devices that generate
CHECKSUM_COMPLETE.  I think if there is padding I will probably just
fall back to the CHECKSUM_NONE case since that seems to be what
IPv4/IPv6 does in their receive calls when they call pskb_trim_rcsum on
padded frames.

Thanks,

Alex
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