pcu_interface: Forward ETWS Primary Notification to PCU

All MS/UE must be notified of ETWS Primary Notifiations.

Depending on their state, the notification goes different paths:
* CS dedicated mode: BSC sends it as L3 message over LAPDm / DCCH
* CS/PS idle mode: BTS sends paging messages on PCH
* PS TBF active: PCU send Packet Application Info

This enables the last of the three methods by passing any
ETWS Primary Notifications received over RSL via the PCU socket into
the PCU.

Change-Id: Ic0b3f38b400a0ca7e4089061ceb6548b0695faa6
Related: OS#4047, OS#4048

4 files changed, 36 insertions, 0 deletions

diff --git a/include/osmo-bts/pcu_if.h b/include/osmo-bts/pcu_if.h
index 6253c84c..114f87d1 100644
--- a/include/osmo-bts/pcu_if.h
+++ b/include/osmo-bts/pcu_if.h
@@ -5,6 +5,7 @@ extern int pcu_direct;
 
 int pcu_tx_info_ind(void);
 int pcu_tx_si13(const struct gsm_bts *bts, bool enable);
+int pcu_tx_app_info_req(struct gsm_bts *bts, uint8_t app_type, uint8_t len, const uint8_t *app_data);
 int pcu_tx_rts_req(struct gsm_bts_trx_ts *ts, uint8_t is_ptcch, uint32_t fn,
 	uint16_t arfcn, uint8_t block_nr);
 int pcu_tx_data_ind(struct gsm_bts_trx_ts *ts, uint8_t is_ptcch, uint32_t fn,
diff --git a/include/osmo-bts/pcuif_proto.h b/include/osmo-bts/pcuif_proto.h
index 144fba68..2d24c434 100644
--- a/include/osmo-bts/pcuif_proto.h
+++ b/include/osmo-bts/pcuif_proto.h
@@ -13,6 +13,7 @@
 #define PCU_IF_MSG_DATA_CNF	0x01	/* confirm (e.g. transmission on PCH) */
 #define PCU_IF_MSG_DATA_IND	0x02	/* receive data from given channel */
 #define PCU_IF_MSG_SUSP_REQ	0x03	/* BTS forwards GPRS SUSP REQ to PCU */
+#define PCU_IF_MSG_APP_INFO_REQ	0x04	/* BTS asks PCU to tranmit APP INFO via PACCH */
 #define PCU_IF_MSG_RTS_REQ	0x10	/* ready to send request */
 #define PCU_IF_MSG_DATA_CNF_DT	0x11	/* confirm (with direct tlli) */
 #define PCU_IF_MSG_RACH_IND	0x22	/* receive RACH */
@@ -172,6 +173,13 @@ struct gsm_pcu_if_pag_req {
 	uint8_t		identity_lv[9];
 } __attribute__ ((packed));
 
+/* BTS tells PCU to [once] send given application data via PACCH to all UE with active TBF */
+struct gsm_pcu_if_app_info_req {
+	uint8_t		application_type; /* 4bit field, see TS 44.060 11.2.47 */
+	uint8_t		len;		  /* length of data */
+	uint8_t		data[162];	  /* random size choice; ETWS needs 56 bytes */
+} __attribute__ ((packed));
+
 /* BTS tells PCU about a GPRS SUSPENSION REQUEST received on DCCH */
 struct gsm_pcu_if_susp_req {
 	uint32_t	tlli;
@@ -198,6 +206,7 @@ struct gsm_pcu_if {
 		struct gsm_pcu_if_act_req	act_req;
 		struct gsm_pcu_if_time_ind	time_ind;
 		struct gsm_pcu_if_pag_req	pag_req;
+		struct gsm_pcu_if_app_info_req	app_info_req;
 	} u;
 } __attribute__ ((packed));
 
diff --git a/src/common/pcu_sock.c b/src/common/pcu_sock.c
index 84a98f5e..ba9e1721 100644
--- a/src/common/pcu_sock.c
+++ b/src/common/pcu_sock.c
@@ -290,6 +290,27 @@ static int pcu_if_signal_cb(unsigned int subsys, unsigned int signal,
 	return 0;
 }
 
+int pcu_tx_app_info_req(struct gsm_bts *bts, uint8_t app_type, uint8_t len, const uint8_t *app_data)
+{
+	struct gsm_pcu_if_app_info_req *ai_req;
+	struct gsm_pcu_if *pcu_prim;
+	struct msgb *msg;
+
+	if (app_type & 0xF0 || len > sizeof(ai_req->data))
+		return -EINVAL;
+
+	msg = pcu_msgb_alloc(PCU_IF_MSG_APP_INFO_REQ, bts->nr);
+	if (!msg)
+		return -ENOMEM;
+	pcu_prim = (struct gsm_pcu_if *) msg->data;
+	ai_req = &pcu_prim->u.app_info_req;
+
+	ai_req->application_type = app_type;
+	ai_req->len = len;
+	memcpy(ai_req->data, app_data, ai_req->len);
+
+	return pcu_sock_send(&bts_gsmnet, msg);
+}
 
 int pcu_tx_rts_req(struct gsm_bts_trx_ts *ts, uint8_t is_ptcch, uint32_t fn,
 	uint16_t arfcn, uint8_t block_nr)
diff --git a/src/common/rsl.c b/src/common/rsl.c
index 0bcad4c0..056c16d8 100644
--- a/src/common/rsl.c
+++ b/src/common/rsl.c
@@ -558,6 +558,11 @@ static int rsl_rx_osmo_etws_cmd(struct gsm_bts_trx *trx, struct msgb *msg)
 
 		/* toggle the PNI to allow phones to distinguish new from old primary notification */
 		bts->etws.pni = !bts->etws.pni;
+
+		/* forward the request to the PCU, so the PCU can send it over any active TBF
+		 * to phones which currently don't listen to the paging channel */
+		pcu_tx_app_info_req(bts, 0, TLVP_LEN(&tp, RSL_IE_SMSCB_MSG),
+				    TLVP_VAL(&tp, RSL_IE_SMSCB_MSG));
 	}
 	return 0;
 }