[GPRS] BSSGP/SGSN: Implement Gb-Interface Paging

We now have a function that generates BSSGP PS and CS paging request.

It is called from the libgtp code when we receive a GTP packet from
the GGSN for a MM context that is in SUSPEND state.  We then issue
a PS paging request to the Cell with the BVCI where the last RA update
was being performed.

TODO: We still don't enqueue the GTP packet (and transmit it on paging
complete), and we don't rate-limit the paging requests, i.e. every GTP packet
will trigger another paging request.

We probably also need some kind of logic that marks the phone as UNREGISTERED
if it doesn't respond to paging requests for some time.

1 files changed, 27 insertions, 0 deletions

diff --git a/openbsc/include/openbsc/gprs_bssgp.h b/openbsc/include/openbsc/gprs_bssgp.h
index 9eaf989af..e432cf750 100644
--- a/openbsc/include/openbsc/gprs_bssgp.h
+++ b/openbsc/include/openbsc/gprs_bssgp.h
@@ -199,6 +199,33 @@ static inline int bssgp_tlv_parse(struct tlv_parsed *tp, uint8_t *buf, int len)
 	return tlv_parse(tp, &tvlv_att_def, buf, len, 0, 0);
 }
 
+enum bssgp_paging_mode {
+	BSSGP_PAGING_PS,
+	BSSGP_PAGING_CS,
+};
+
+enum bssgp_paging_scope {
+	BSSGP_PAGING_BSS_AREA,		/* all cells in BSS */
+	BSSGP_PAGING_LOCATION_AREA,	/* all cells in LA */
+	BSSGP_PAGING_ROUTEING_AREA,	/* all cells in RA */
+	BSSGP_PAGING_BVCI,		/* one cell */
+};
+
+struct bssgp_paging_info {
+	enum bssgp_paging_mode mode;
+	enum bssgp_paging_scope scope;
+	struct gprs_ra_id raid;
+	uint16_t bvci;
+	const char *imsi;
+	uint32_t *ptmsi;
+	uint16_t drx_params;
+	uint8_t qos[3];
+};
+
+/* Send a single GMM-PAGING.req to a given NSEI/NS-BVCI */
+int gprs_bssgp_tx_paging(uint16_t nsei, uint16_t ns_bvci,
+			 struct bssgp_paging_info *pinfo);
+
 /* gprs_bssgp_vty.c */
 int gprs_bssgp_vty_init(void);