source *and* destination port and/or both the source *and* destination
address passed to "find_conversation()", because the packet for which
you're trying to find the conversation may be going in the opposite
direction to the packet for which the conversation was originally
created.
Create different hash tables for wildcarded conversations, to reduce the
number of "is this a wildcard?" tests done when doing hash lookups.
This is sufficient to allow the TFTP dissector to use conversations
rather than being special-cased in the UDP dissector, and may also be
sufficient to handle a similar problem with SMTP (request goes from
client IP X port Y to server IP Z's well-known port, reply comes back
from some other port on server Z to client IP X port Y), but further use
may reveal other changes that should be made.
svn path=/trunk/; revision=2525
