netdev - Re: [PATCH] lro: IP fragment checking

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Message-ID: <493423D7.5030203@myri.com>
Date:	Mon, 01 Dec 2008 12:50:15 -0500
From:	Andrew Gallatin <gallatin@...i.com>
To:	Jan-Bernd Themann <ossthema@...ibm.com>
CC:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
	linux-kernel <linux-kernel@...r.kernel.org>, tklein@...ibm.com,
	Christoph Raisch <raisch@...ibm.com>, jb.billaud@...il.com,
	hering2@...ibm.com
Subject: Re: [PATCH] lro: IP fragment checking

Jan-Bernd Themann wrote:
> This patch prevents that ip fragmented TCP packets are considered vaild
> for aggregation

<...>

> +	if (iph->frag_off & IP_MF)
> +		return -1;
> +

I think there is an endian bug, and that you should also check
IP_OFFSET.  What about:

	if (iph->frag_off & htons(IP_MF|IP_OFFSET))

As to whether or not to do it in the drivers/hardware or in the
LRO code, I favor doing it in the LRO code just so that it is not
missed in some driver.

Drew
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