On Mon, Sep 22, 2008 at 01:12:45PM -0700, David Miller wrote:
> From: Nickolay Vinogradov <nickolay@xxxxxxxxx>
> Date: Mon, 22 Sep 2008 19:58:26 +0400
>
> CC:'ing correct mailing lists...
>
> > SCTP checksum calculation fix for BigEndian.
> > ntohl() doesn't do anything on BigEndian.
> >
> > diff --git a/Makefile b/Makefile
> > diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
> > index ba75c67..2f0ed64 100644
> > --- a/include/net/sctp/checksum.h
> > +++ b/include/net/sctp/checksum.h
> > @@ -74,5 +74,19 @@ static inline __u32 sctp_update_cksum(__u8 *buffer, __u16 length, __u32 crc32)
> >
> > static inline __u32 sctp_end_cksum(__u32 crc32)
> > {
> > - return ntohl(~crc32);
> > + __u32 result;
> > + __u8 byte0, byte1, byte2, byte3;
> > +
> > + result = ~crc32;
> > +
> > + byte0 = result & 0xff;
> > + byte1 = (result>>8) & 0xff;
> > + byte2 = (result>>16) & 0xff;
> > + byte3 = (result>>24) & 0xff;
> > +
> > + crc32 = ((byte0 << 24) |
> > + (byte1 << 16) |
> > + (byte2 << 8) |
> > + byte3);
> > + return crc32;
> > }
Nickolay,
you should use swab32(~crc32) instead. It will make use of arch-specific
optimisations when available (eg: bswap on x86).
Willy
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