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Date: Fri, 29 Aug 2008 15:16:58 -0400
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From: gnn@freebsd.org
To: Luigi Rizzo <rizzo@iet.unipi.it>
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Cc: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net>,
	Sam Leffler <sam@freebsd.org>, net@freebsd.org
Subject: Re: Small patch to multicast code...
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At Fri, 29 Aug 2008 18:28:53 +0200,
Luigi Rizzo wrote:
> 
> and to be more explicit - the result of m_pullup is that
> the number of bytes specified as m_pullup argument are in
> a private piece of memory -- the 'data' region within the mbuf -- so
> you can freely play with them without trouble.
> 
> That is why i suggested to just increase the argument to m_pullup
> by the size of the udp header so one can overwrite the checksum
> within the mbuf without touching the shared part in the cluster
> (if any).

I tried various versions of that, but then I noticed that I also had
to save out the pkthdr structure as well.  Did you come up with a
faster workable patch?

For now I'm going to commit the patch I sent originally.

Best,
George