On Mar 16, 2009, at 3:45 PM, Joerg Mayer wrote:
> On Mon, Mar 16, 2009 at 09:40:03PM +0000, [email protected] wrote:
>> http://anonsvn.wireshark.org/viewvc/viewvc.cgi?
>> view=rev&revision=27748
>> crc16 algorithm copied from Linux sources (GPL V2 only!)
>
> So far the wireshark sources are v2 or later - so adding a gplv2
> only file
> is not something that should be done without asking *first*, because
> it
> has effects for all of Wireshark. Or maybe there already were files
> that
> are v2 only and I missed that?
Is the only difference between the CRC16 in PROFINET and the ITU-T
CRC16 implemented in epan/crc16.c the polynomial? It looks as if the
algorithm is the same in the PROFINET CRC16 and the "reflected" ITU-T
CRC16:
crc = initial value;
for (all bytes in the buffer)
crc = (crc >> 8) ^ table[(crc ^ byte from buffer) & 0xff];
return crc;
so it might just be the table. If so, could we just generate the
appropriate table for the PROFINET polynomial, have epan/crc16.c
export crc16_reflected(), and have the PROFINET CRC16 routine use
crc16_reflected() and the appropriate table?
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