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From: Ulrich Drepper <drepper@redhat.com>
To: Linux Kernel <linux-kernel@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Subject: ntohs/ntohl and bitops
Date: Tue, 10 Jan 2006 14:02:52 -0800	[thread overview]
Message-ID: <43C42F0C.10008@redhat.com> (raw)

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I just saw this in a patch:

+               if (ntohs(ih->frag_off) & IP_OFFSET)
+                       return EBT_NOMATCH;

This isn't optimal, it requires a byte switch little endian machines.
The compiler isn't smart enough.  It would be better to use

     if (ih->frag_off & ntohs(IP_OFFSET))

where the byte-swap can be done at compile time.  This is kind of ugly,
I guess, so maybe a dedicate macro

    net_host_bit_p(ih->frag_off, IP_OFFSET)

??

-- 
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖


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             reply	other threads:[~2006-01-10 22:03 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-10 22:02 Ulrich Drepper [this message]
2006-01-11  8:00 ` ntohs/ntohl and bitops David S. Miller
2006-01-11  8:13   ` Arjan van de Ven
2006-01-11  8:36     ` David S. Miller
2006-01-11  8:36     ` Ulrich Drepper
2006-01-11  8:44       ` David S. Miller
2006-01-11  9:48         ` Jakub Jelinek
2006-01-11 18:35           ` Jan Engelhardt
2006-01-11 18:45             ` Ulrich Drepper
2006-01-11 20:19               ` David S. Miller
2006-01-12  1:04   ` Pavel Machek
2006-01-14  9:52     ` YOSHIFUJI Hideaki / 吉藤英明
2006-01-15  1:46     ` David S. Miller

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