[sr-dev] Problem with Registration on pcscf

[Paul Pankhurst]

I've noticed a problem with registrations on the pcscf when doing some 
testing with sipp

If I send in a REGISTER with SIPP followed by an INVITE calls go through 
my system no problem.
If I then stop the sipp script and run it again, I find that although 
the registration succeeds, subsequent INVITES are rejected telling me 
that I have not registered!
If I unregister at the end of my script everything is fine, and the 
problem goes away after the original REGISTRATION times out, so this led 
me to think that we had a problem with multiple registrations entries in 
the system.

The problem seems to be a result of the fact that sipp always places the 
same ip address and port number on the contact line when using tcp 
connections.

I've had a look through the code and believe that we are getting 
multiple entries in the usrloc hash table in this scenario, and 
ul_get_pcontact only ever returns the first one which causes 
pcscf_is_registered to incorrectly report that the UE is not registered.

Paul