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From: Jeff Garzik <jgarzik@pobox.com>
To: Dennis Cook <cook@sandgate.com>
Cc: linux-kernel@vger.kernel.org, kernelnewbies@nl.linux.org
Subject: Re: Deactivating TCP checksumming
Date: Thu, 03 Apr 2003 15:47:25 -0500	[thread overview]
Message-ID: <3E8C9DDD.3080205@pobox.com> (raw)
In-Reply-To: <b6i5t1$h0t$1@main.gmane.org>

Dennis Cook wrote:
> Based on various feedback, on my RH Linux 2.4.18 kernel I tried the
> following:
> 
> Set "features" bit NETIF_F_IP_CSUM set (the only feature bit set).
> In my network driver start-transmit check for "CHECKSUM_HW" in ip_summed.
> Using a small test program, use "sendfile" to copy a file to a network
> socket FD.
> Result is none of the packets presented to my network adapter driver have
> ip_summed set to CHECKSUM_HW, so the SW IP stack has already
> computed checksums.

CHECKSUM_HW is for receive, not transmit.  Read the comments at the top 
of include/linux/skbuff.h.


> Is this mechanism possibly broken on kernel 2.4?


it works quite well.

	Jeff



  reply	other threads:[~2003-04-03 20:35 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-04-01 12:12 Deactivating TCP checksumming shesha bhushan
2003-04-01 12:28 ` Matti Aarnio
2003-04-02 19:22   ` Dennis Cook
2003-04-02 20:36     ` Jeff Garzik
2003-04-02 20:47       ` Dennis Cook
2003-04-02 20:58         ` Jeff Garzik
2003-04-03 20:34           ` Dennis Cook
2003-04-03 20:47             ` Jeff Garzik [this message]
2003-04-03 20:57               ` Dennis Cook
2003-04-04 14:20                 ` Jeff Garzik
2003-04-04 14:08               ` Abhishek Agrawal
2003-04-04  4:41             ` Ion Badulescu
2003-04-02 21:03         ` Richard B. Johnson
2003-04-02 21:22           ` Dennis Cook
  -- strict thread matches above, loose matches on Subject: below --
2003-04-01  9:47 shesha bhushan
2003-04-01 10:58 ` Matti Aarnio

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