This module is able to match a SCCP message against a given
Destination-GT prefix and checks if the message contains an
Invoke(SRI-for-SM). If both conditions are true, it alters the TT from
whatever it may currently be to 3.
This is used for SMS special routing cases at the STP.
When the MSC responds with a SRI-SM-Response, we match against a
user-supplied list of IMSs. If there is a match, we replace the
known prefix of the IMSI with a new known prefix.
This allows us to use the osmo_ss7_gtt module for matching Sccp
addresses including GT ranges.
The eunit tests have been extended to test the new code.