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Date: Mon, 24 Oct 2005 11:51:01 +0200
From: Simon 'corecode' Schubert <corecode@fs.ei.tum.de>
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To: kamal kc <kamal_ckk@yahoo.com>
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Cc: Giorgos Keramidas <keramida@ceid.upatras.gr>,
	freebsd <freebsd-hackers@freebsd.org>, freebsd <freebsd-net@freebsd.org>
Subject: Re: in_cksum() for ip packets with multiple mbufs
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kamal kc wrote:
>    -  final thing does this makes any difference
>      (calling the htons() twice):
> 
>       ip->ip_id=htons(ip->ip_id);
>       ip->ip_id=htons(ip->ip_id);

on little endian machines: yes.  on big endian machines:  no.  So don't 
do it. :)

freebsd has several fields of the ip headerin host byte order to speed 
up access.  they get converted to network byte order at a very late 
stage of the ip output path.

cheers
   simon

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