Messages in this thread | | | Date | Thu, 12 Jan 2006 01:04:06 +0000 | From | Pavel Machek <> | Subject | Re: ntohs/ntohl and bitops |
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On Wed 11-01-06 00:00:20, David S. Miller wrote: > From: Ulrich Drepper <drepper@redhat.com> > Date: Tue, 10 Jan 2006 14:02:52 -0800 > > > 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) > > The first suggestion isn't considered ugly, and the best form is: > > if (ih->frag_off & __constant_htons(IP_OFFSET)) > > I'll fix that up when I get a chance, thanks for catching it Uli.
Could you possibly #define IP_OFFSET htons(1234) ?
Noone should need it in native endianity, no?
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