From owner-freebsd-net@FreeBSD.ORG  Tue Apr 27 14:16:41 2004
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Date: Tue, 27 Apr 2004 23:16:39 +0200
From: Mark Santcroos <marks@ripe.net>
To: Ruslan Ermilov <ru@freebsd.org>
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cc: net@freebsd.org
Subject: Re: udp checksum on raw sockets
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Hi,

On Tue, Apr 27, 2004 at 10:05:43PM +0300, Ruslan Ermilov wrote:
> Have the raw IP code set csum_flags |= CSUM_UDP (and set csum_data
> correctly) in m->m_pkthdr, if ip_p == IPPROTO_UDP && uh_csum == 0.
> Do the same thing for IPPROTO_TCP.

Like I said, I'm willing to tackle this in the kernel, but for now I also 
need a userland-only solution.

I guess I can fetch the IP address from the first ethernet iface and use
that as the src address for the IP packet.

Then I have enough information to calculate the UDP checksum in userland,
don't I?

Thanks

Mark