SMSCB: Send ETWS primary warning message via all dedicated channels

As soon as we have received an ETWS primary notification message from
the CBC, we should transmit it as "RR Application Information" to all
dedicated channels.

Change-Id: I913d0237cffdcb95037da8489acef5f32a7fc02e

1 files changed, 61 insertions, 2 deletions

diff --git a/src/osmo-bsc/smscb.c b/src/osmo-bsc/smscb.c
index 6b9608652..319ef21a7 100644
--- a/src/osmo-bsc/smscb.c
+++ b/src/osmo-bsc/smscb.c
@@ -25,10 +25,12 @@
 #include <osmocom/core/select.h>
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/talloc.h>
+#include <osmocom/core/byteswap.h>
 
 #include <osmocom/gsm/cbsp.h>
 #include <osmocom/gsm/protocol/gsm_23_041.h>
 #include <osmocom/gsm/protocol/gsm_48_049.h>
+#include <osmocom/gsm/protocol/gsm_03_41.h>
 
 #include <osmocom/netif/stream.h>
 
@@ -36,6 +38,8 @@
 #include <osmocom/bsc/gsm_data.h>
 #include <osmocom/bsc/smscb.h>
 #include <osmocom/bsc/vty.h>
+#include <osmocom/bsc/gsm_04_08_rr.h>
+#include <osmocom/bsc/lchan_fsm.h>
 
 /*********************************************************************************
  * Helper Functions
@@ -52,6 +56,26 @@ static void llist_replace_head(struct llist_head *new, struct llist_head *old)
 	INIT_LLIST_HEAD(old);
 }
 
+#define ETWS_PRIM_NOTIF_SIZE	56
+
+/* Build a ETWS Primary Notification message as per TS 23.041 9.4.1.3 */
+static int gen_etws_primary_notification(uint8_t *out, uint16_t serial_nr, uint16_t msg_id,
+					 uint16_t warn_type, const uint8_t *sec_info)
+{
+	struct gsm341_etws_message *etws = (struct gsm341_etws_message *)out;
+
+	memset(out, 0, ETWS_PRIM_NOTIF_SIZE);
+
+	osmo_store16be(serial_nr, out);
+	etws->msg_id = osmo_htons(msg_id);
+	etws->warning_type = osmo_htons(warn_type);
+
+	if (sec_info)
+		memcpy(etws->data, sec_info, ETWS_PRIM_NOTIF_SIZE - sizeof(*etws));
+
+	return ETWS_PRIM_NOTIF_SIZE;
+}
+
 /*! Obtain SMSCB Channel State for given BTS (basic or extended CBCH) */
 struct bts_smscb_chan_state *bts_get_smscb_chan(struct gsm_bts *bts, bool extended)
 {
@@ -437,6 +461,39 @@ static int tx_cbsp_keepalive_compl(struct bsc_cbc_link *cbc)
  * Per-BTS Processing of CBSP from CBC, called via cbsp_per_bts()
  *********************************************************************************/
 
+static void etws_primary_to_dedicated(struct gsm_bts *bts,
+				      const struct osmo_cbsp_write_replace *wrepl)
+{
+	uint8_t etws_primary[ETWS_PRIM_NOTIF_SIZE];
+	struct gsm_bts_trx *trx;
+	unsigned int count = 0;
+	int i, j;
+
+	gen_etws_primary_notification(etws_primary, wrepl->new_serial_nr, wrepl->msg_id,
+				      wrepl->u.emergency.warning_type,
+				      wrepl->u.emergency.warning_sec_info);
+
+	/* iterate over all lchan in each TS in each TRX of this BTS */
+	llist_for_each_entry(trx, &bts->trx_list, list) {
+		for (i = 0; i < ARRAY_SIZE(trx->ts); i++) {
+			struct gsm_bts_trx_ts *ts = &trx->ts[i];
+			for (j = 0; j < ARRAY_SIZE(ts->lchan); j++) {
+				struct gsm_lchan *lchan = &ts->lchan[j];
+				if (!lchan_may_receive_data(lchan))
+					continue;
+				gsm48_send_rr_app_info(lchan, 0x1, 0x0, etws_primary,
+							sizeof(etws_primary));
+				count++;
+			}
+		}
+	}
+
+	LOG_BTS(bts, DCBS, LOGL_NOTICE, "Sent ETWS Primary Notification via %u dedicated channels\n",
+		count);
+
+	/* FIXME: Notify BTS of primary ETWS notification via vendor-specific Abis message */
+}
+
 /*! Try to execute a write-replace operation; roll-back if it fails.
  *  \param[in] chan_state BTS CBCH channel state
  *  \param[in] extended_cbch Basic (false) or Extended (true) CBCH
@@ -506,8 +563,10 @@ static int bts_rx_write_replace(struct gsm_bts *bts, const struct osmo_cbsp_deco
 	int rc;
 
 	if (!wrepl->is_cbs) {
-		LOG_BTS(bts, DCBS, LOGL_ERROR, "(Primary) Emergency Message not supported\n");
-		return -CBSP_CAUSE_CB_NOT_SUPPORTED;
+		/* send through any active dedicated channels of this BTS */
+		etws_primary_to_dedicated(bts, wrepl);
+		/* TODO: send via RSL to BTS for transmission on PCH */
+		return 0;
 	}
 
 	/* check if cell has a CBCH at all */