Well, i dont know you skills on programming and O.S. but....

Since this a security forum what about a script, program, whatever that get an Netfilter (a.k.a. Iptables) set of rules as input and create a flow diagram of all rules? As an enhancement, you can supply some packet caracteristcs (or even a packet) and script will show you which rules will be hit....

Kinda dunb, uh?