[SR-Users] unregister user when kamailio looses TCP connection.

Hello, I've made a patch to kamailio-4.0.3 which removes stale registration when kamailio looses an incoming tcp connection. Of course this patch needs more work. Since the are no direct references between user location contacts and tcp connections callback function uses linear search through the whole location table using received field as a key. Can anybody more experienced in kamailio internals check if I chose the right place to get information about lost tcp connections ? Another thing I wanted to ask is maybe somebody can suggest a better way to tie a tcp connection to the user location information without complicating "usrloc" module by any heavy data structures. If anybody else except me need this It would be great to fix known problems and add it to kamailio.