2008/9/10 Maynard, Chris
<Christopher.Maynard@xxxxxxxxx>
Should we ever see instances where conversation_new() is called without
a preceding find_conversation()?
I have found 3 such dissectors, and the code seems suspicious to me.
The 3 are:
packet-bittorrent.c
packet-dtpt.c
packet-quake.c
- Chris
In the case of packet-bittorrent.c there should really be a call to find_conversation preceeding the call to conversation_new although I can see the reason for why the implementor did not do this (if there is some thought behind it and not just a slip).
Since the call to conversation_new is (only) part of the heuristic dissection, this means that packet-bittorrent attempts to find bittorrent traffic on (especially) other ports than the pre-defined ones. When such a port is found it is very unlikely that the 4-tuple that defines the connection (src and dest IP addresses and ports) will already have been seen by the dissector before. Hence, it is very unlikely that a second conversation_new would occur for the same 4-tuple that has been used in packet-bittorrent's conversation_new before, but not impossible of course.
There should definately be a call to find_conversation preceeding the call to conversation_new in packet-quake.c.
Regards, Peter
