Wireshark · Wireshark-dev: [Wireshark-dev] best practice questions - a tn3270 dissector

[Robert Hogan <robert@xxxxxxxxxxxxxxx>]

I'm most of the way (I hope) through a tn3270 dissector. However I'm not 
sure of the most acceptable way of doing a couple of things:

- Should I just make TN3270 a sub-dissector of telnet? So users 
select 'decode as telnet' and get the tn3270 dissected implicitly? Or 
should it have a separate 'decode as' entry? If the latter, I'm not sure 
how I can call telnet as a 'super-dissector' or alternatively, avoid 
duplicating code.

- The best way of recognizing a tn3270 session is through the 'terminal 
type' telnet option at session negotiation. Browsing through other 
dissector code I can't find a canonical way of storing information about a 
given stream, other than possibly misusing the conversation api. I'm sure 
I'm missing a trick. What is the standard way of recognizing that a packet 
is from a stream previously identified as requiring a specific 
sub-dissector?

Thanks!
Robert