bluetooth: services: Support aborted procedures/subevents in RAS

1. When a subevent in a procedure is aborted:
- Encode ranging data in RRSP such that num_steps_reported is 0 if a
  subevent was aborted
  -> if some steps in the subevent were successful, these will still be
     discarded.
  -> subsequent subevents in the procedure will no longer be dropped.
- Update parser API in RREQ to continue parsing subevent headers if a
  subevent header with num_steps_reported=0 is seen
- Update sample to make use of these extra steps.
  Note that this doesn't impact the behavior of the sample because
  the subevent length is currently large enough to fit the entire
  procedure.

2. When procedure_done_status is 0xF:
- Notify RREQ subscribers with RD Ready.
  -> this is important because some subevents in the procedure may
     have successfully performed some steps

Signed-off-by: Olivier Lesage <[email protected]>

Author: olivier-le-sage

samples/bluetooth/channel_sounding_ras_initiator/src/main.c

@@ -56,19 +56,13 @@ static void subevent_result_cb(struct bt_conn *conn, struct bt_conn_le_cs_subeve
 {
 	LOG_INF("Subevent result callback %d", result->header.procedure_counter);
 
-	if (result->header.subevent_done_status == BT_CONN_LE_CS_SUBEVENT_ABORTED) {
-		/* If this subevent was aborted, drop the entire procedure for now. */
-		LOG_WRN("Subevent aborted");
-		dropped_ranging_counter = result->header.procedure_counter;
-		net_buf_simple_reset(&latest_local_steps);
-		return;
-	}
-
 	if (dropped_ranging_counter == result->header.procedure_counter) {
 		return;
 	}
 
-	if (result->step_data_buf) {
+	if (result->header.subevent_done_status == BT_CONN_LE_CS_SUBEVENT_ABORTED) {
+		/* The steps from this subevent will not be used. */
+	} else if (result->step_data_buf) {
 		if (result->step_data_buf->len <= net_buf_simple_tailroom(&latest_local_steps)) {
 			uint16_t len = result->step_data_buf->len;
 			uint8_t *step_data = net_buf_simple_pull_mem(result->step_data_buf, len);
@@ -91,7 +85,7 @@ static void subevent_result_cb(struct bt_conn *conn, struct bt_conn_le_cs_subeve
 		most_recent_local_ranging_counter = result->header.procedure_counter;
 		k_sem_give(&sem_procedure_done);
 	} else if (result->header.procedure_done_status == BT_CONN_LE_CS_PROCEDURE_ABORTED) {
-		LOG_WRN("Procedure aborted");
+		LOG_WRN("Procedure %u aborted", result->header.procedure_counter);
 		net_buf_simple_reset(&latest_local_steps);
 	}
 }

subsys/bluetooth/services/ras/rreq/ras_rreq.c

@@ -977,7 +977,10 @@ void bt_ras_rreq_rd_subevent_data_parse(struct net_buf_simple *peer_ranging_data
 					bt_ras_rreq_subevent_header_cb_t subevent_header_cb,
 					bt_ras_rreq_step_data_cb_t step_data_cb, void *user_data)
 {
-	if (!peer_ranging_data_buf || !local_step_data_buf) {
+	if (!peer_ranging_data_buf
+		|| !local_step_data_buf
+		|| peer_ranging_data_buf->len == 0
+		|| local_step_data_buf->len == 0) {
 		LOG_ERR("Tried to parse empty step data.");
 		return;
 	}
@@ -994,8 +997,13 @@ void bt_ras_rreq_rd_subevent_data_parse(struct net_buf_simple *peer_ranging_data
 			return;
 		}
 
-		if (peer_subevent_header_data->num_steps_reported == 0 ||
-		    peer_ranging_data_buf->len == 0) {
+		if (peer_subevent_header_data->num_steps_reported == 0) {
+			LOG_DBG("Skipping subevent with no steps.");
+			continue;
+		}
+
+		if (peer_ranging_data_buf->len == 0) {
+			LOG_WRN("Empty peer step data buf where steps were expected.");
 			return;
 		}
 

subsys/bluetooth/services/ras/rrsp/ras_rd_buffer.c

@@ -200,14 +200,14 @@ static void subevent_data_available(struct bt_conn *conn,
 	__ASSERT_NO_MSG(conn_index < ARRAY_SIZE(tx_power_cache));
 	__ASSERT_NO_MSG(conn_index < ARRAY_SIZE(drop_procedure_counter));
 
-	if (result->header.subevent_done_status == BT_CONN_LE_CS_SUBEVENT_ABORTED) {
-		/* If this subevent was aborted, drop the entire procedure for now. */
+	if (result->header.procedure_done_status == BT_CONN_LE_CS_PROCEDURE_ABORTED) {
+		LOG_DBG("Procedure was aborted.");
 		drop_procedure_counter[conn_index] = result->header.procedure_counter;
 	}
 
 	if (drop_procedure_counter[conn_index] == result->header.procedure_counter) {
 		/* This procedure will not be sent to the peer, so ignore all data. */
-		LOG_WRN("Dropping subevent data for procedure %u",
+		LOG_DBG("Dropping subevent data for procedure %u",
 			result->header.procedure_counter);
 
 		if (buf) {
@@ -261,10 +261,17 @@ static void subevent_data_available(struct bt_conn *conn,
 	hdr->ranging_abort_reason = result->header.procedure_abort_reason;
 	hdr->subevent_abort_reason = result->header.subevent_abort_reason;
 	hdr->ref_power_level = result->header.reference_power_level;
-	hdr->num_steps_reported = result->header.num_steps_reported;
 
-	if (result->step_data_buf) {
-		bt_le_cs_step_data_parse(result->step_data_buf, process_step_data, buf);
+	if (result->header.subevent_done_status == BT_CONN_LE_CS_SUBEVENT_ABORTED) {
+		hdr->num_steps_reported = 0;
+		LOG_DBG("Discarding %u steps in aborted subevent",
+			result->header.num_steps_reported);
+	} else {
+		hdr->num_steps_reported = result->header.num_steps_reported;
+
+		if (result->step_data_buf) {
+			bt_le_cs_step_data_parse(result->step_data_buf, process_step_data, buf);
+		}
 	}
 
 	/* process_step_data might have requested dropping this procedure. */
@@ -275,7 +282,8 @@ static void subevent_data_available(struct bt_conn *conn,
 		return;
 	}
 
-	if (hdr->ranging_done_status == BT_CONN_LE_CS_PROCEDURE_COMPLETE) {
+	if (hdr->ranging_done_status == BT_CONN_LE_CS_PROCEDURE_COMPLETE ||
+	    hdr->ranging_done_status == BT_CONN_LE_CS_PROCEDURE_ABORTED) {
 		buf->ready = true;
 		buf->busy = false;
 		notify_new_rd_stored(conn, result->header.procedure_counter);