Currently the authorization of an IMSI is done by checking ACLs
synchronously which is not feasible when the subscriber data has to
be retrieved from an external source.
This patch changes this by using a callback when the information is
available. This is also done when only ACL are checked, in this case
the callback is invoked from within sgsn_auth_request(). The callback
function sgsn_update_subscriber_data calls sgsn_auth_update which
in turn calls either gsm0408_gprs_access_granted or
gsm0408_gprs_access_denied. gsm48_gmm_authorize is extended by a call
to sgsn_auth_request when IMSI and IMEI are available but the
auth_state is unknown.
The change has been successfully tested with single phones (E71 and
IPhone 5c).
Sponsored-by: On-Waves ehf
423f8bfa02