gprs: Use PURGE MS messages
When a subscriber entry is going to be deleted by SGSN and when the
subscriber info has been obtained from a remote peer via GSUP, the
peer should be informed before the entry is really deleted. For this
purpose, MAP defines the PURGE MS procedure (see GSM 09.02, 19.1.4).
This patch adds support for the PURGE_MS_REQ/_ERR/_RES messages and
invokes the procedure when the subscriber entry is going to be
removed. This only applies if GSUP is being used, the Update
Location procedure has been completed successfully, and the
subscriber has not been cancelled. The removal of the entry is
delayed until a PURGE_MS_RES or PURGE_MS_ERR message is received.
Note that GSM 09.02, 19.1.4.4 implies that the subscriber data is not
to be removed when the procedure fails which is not the way the
feature has been implemented.
Note that handling 'P-TMSI freezing' is not implemented.
Ticket: OW#1338
Sponsored-by: On-Waves ehf
4 files changed