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From: Gerrit Renker <gerrit@erg.abdn.ac.uk>
To: Chris Lalancette <clalance@redhat.com>
Cc: netdev@vger.kernel.org
Subject: Re: Zero checksum in netconsole/netdump packets
Date: Tue, 7 Nov 2006 10:09:02 +0000	[thread overview]
Message-ID: <200611071009.02424@strip-the-willow> (raw)
In-Reply-To: <454FC80B.9090001@redhat.com>

Quoting Chris Lalancette:
|  Hello,
|       I realized that all of the packets that go from the crashing machine to the netdump server have a zero checksum. 
<snip>
|       Assuming that this is just an oversight, attached is a simple patch to compute the UDP checksum in netpoll_send_udp.
|  
|  Signed-off-by: Chris Lalancette <clalance@redhat.com>
|  
RFC 768 allows to not compute the checksum by leaving uh->check at 0 - hence it is not illegal.
But without David's suggestion the code is not valid, since otherwise there is no way of 
distinguishing a computed `0' from an ignored `0' field:
 if ( udph->check == 0 )
	udph->check = -1;

  parent reply	other threads:[~2006-11-07 10:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-06 23:40 Zero checksum in netconsole/netdump packets Chris Lalancette
2006-11-07  7:16 ` David Miller
2006-11-07 13:33   ` Chris Lalancette
2006-11-07 22:56     ` David Miller
2006-11-07 10:09 ` Gerrit Renker [this message]
2006-11-07 11:35   ` Krzysztof Oledzki

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