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From: Rick Jones <rick.jones2@hp.com>
To: Gaurav Aggarwal <grv.aggarwal@gmail.com>
Cc: netfilter-devel@vger.kernel.org, netdev@vger.kernel.org,
	linux-net@vger.kernel.org, linux-kernel@vger.kernel.org,
	davidsen@tmr.com
Subject: Re: Bad TCP checksum error
Date: Fri, 26 Oct 2007 09:59:16 -0700	[thread overview]
Message-ID: <47221CE4.70103@hp.com> (raw)
In-Reply-To: <1a41e0840710260903w33516f62kc53e5eb56e424d69@mail.gmail.com>

Checksum Offload on the NIC(s) can complicate things.  First, if you are tracing 
on the sender, the tracepoint is before the NIC has computed the full checksum. 
  IIRC only a partial checksum is passed-down to the NIC when CKO is in use.

So, making certain your trace is from the "wire" or the receiver rather than the 
sender would be a good thing, and trying again with CKO disabled on the 
interface(s) (via ethtool) might be something worth looking at.  Ultimately, 
doing the partial checksum modificiations in a CKO-friendly manner might be a 
good thing.

rick jones

      reply	other threads:[~2007-10-26 16:59 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-26  7:41 Bad TCP checksum error Gaurav Aggarwal
2007-10-26 16:03 ` Gaurav Aggarwal
2007-10-26 16:59   ` Rick Jones [this message]

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