generic network protocols parser ?

[gnn at freebsd.org]

At Fri, 4 Mar 2005 11:07:34 -0500,
Aziz KEZZOU wrote:
> 
> Hi all,
> I am wondering if any one knows  about a generic parser which takes a
> packet (mbuf) of a certain protocol (e.g RSVP ) as input and generates
> some data structre representing the packet ?
> 
> I've been searching for a while and found that ethereal and tcpdump
> for example use specific data structres and functions to dissect each
> protocol packets. Is this the only approach possible ?
> 
> My supervisor suggested using a TLV (Type/Length/Value) approach
> instead. Any opinions about that?
> 
> If no such a parser exists is there any practical reason why ?
> 

You might want to look at libnet and libnet-ng.  Start here:

http://www.packetfactory.net/libnet/

Perhaps not exactly what you want but the beginnings are there.

Later,
George