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From: Rask Ingemann Lambertsen <rask@sygehus.dk>
To: francois donzet <fdonzet@yahoo.fr>
Cc: netdev@oss.sgi.com
Subject: Re: problem in driver network code
Date: Fri, 7 Nov 2003 18:15:12 +0100	[thread overview]
Message-ID: <20031107181508.A1102@sygehus.dk> (raw)
In-Reply-To: <20031107083844.74787.qmail@web25202.mail.ukl.yahoo.com>; from fdonzet@yahoo.fr on Fri, Nov 07, 2003 at 09:38:44AM +0100

On Fri, Nov 07, 2003 at 09:38:44AM +0100, francois donzet wrote:
> 
> It seems to me that there is a problem ;). If i store
> in skb->csum a sum of all words of the packet data, it
>  will be unusable by tcp (the skb->csum doesn't
> contain the checksum of tcpheader plus data only, as
> the ipheader is part of the packet when the sum is
> computed)

That can be accounted for by the TCP code because the IP header is known to
the TCP code. IIRC, the pseudoheader is similiar to a real IP header, so it
may take just a few lines of code to make up for the difference, but I
haven't checked that.

What do you do with an IEEE 802.1q (VLAN) or 802.2 (LLC) packet? The VLAN
code in vlan_skb_recv() does not adjust skb->csum or skb->ip_summed. Neither
does the 802.2 code.

-- 
Regards,
Rask Ingemann Lambertsen

  reply	other threads:[~2003-11-07 17:15 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-11-07  8:38 problem in driver network code francois donzet
2003-11-07 17:15 ` Rask Ingemann Lambertsen [this message]
2003-11-10  8:14   ` francois donzet
2003-11-13 21:48     ` hw checksum acceleration (Was: problem in driver network code) Rask Ingemann Lambertsen

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