Wireshark · Wireshark-dev: Re: [Wireshark-dev] [Wireshark-commits] rev 27748:/trunk/plugins/profinet/ /trunk/plugins/profinet/:

[Guy Harris <guy@xxxxxxxxxxxx>]

On Mar 16, 2009, at 4:33 PM, Ulf Lamping wrote:

> I'm not an expert on this stuff, so it might be easy to rewrite the
> existing CRC stuff - but I'm really not an expert on this ...

I'm not, either, but I updated the comment in epan/crc16.c to point to  
Ross Williams' Web site, where he has links to a text and an HTML  
version of his paper.  It has a copy of the algorithm used to generate  
the CRC16 tables for a given polynomial; if you can use it to generate  
the table for the PROFINET CRC16 (so that the numbers are the same as  
the ones in the plugins/profinet/crc16.c file), and make the changes  
to epan/crc16.c to expose the CRC16 routine that takes a table as an  
argument, that should let you use the libwireshark CRC16 routine.

(In addition, reading the paper would make you more of an expert on it  
- more of an expert than me, at least. :-))