Bluetooth: BAP: Improve handling of ASCS notification error

If the num_ase == 0xff then it is a special case that needs to be
handled like if num_ase == 0x01.

If there is an error with ase_id = 0x00 then the error cannot
be translated to a specific stream, so the callbacks may now get
NULL for the stream object.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>

include/zephyr/bluetooth/audio/bap.h

@@ -1126,7 +1126,8 @@ struct bt_bap_unicast_client_cb {
 	 * This will be called for each stream in the group that was being QoS
 	 * configured.
 	 *
-	 * @param stream   Stream the operation was performed on.
+	 * @param stream   Stream the operation was performed on. May be NULL if there is no stream
+	 *                 associated with the ASE ID sent by the server.
 	 * @param rsp_code Response code.
 	 * @param reason   Reason code.
 	 */
@@ -1138,7 +1139,8 @@ struct bt_bap_unicast_client_cb {
 	 *
 	 * Called when the enable operation is completed on the server.
 	 *
-	 * @param stream   Stream the operation was performed on.
+	 * @param stream   Stream the operation was performed on. May be NULL if there is no stream
+	 *                 associated with the ASE ID sent by the server.
 	 * @param rsp_code Response code.
 	 * @param reason   Reason code.
 	 */
@@ -1152,7 +1154,8 @@ struct bt_bap_unicast_client_cb {
 	 * only be called if the stream supplied to bt_bap_stream_start() is
 	 * for a @ref BT_AUDIO_DIR_SOURCE endpoint.
 	 *
-	 * @param stream   Stream the operation was performed on.
+	 * @param stream   Stream the operation was performed on. May be NULL if there is no stream
+	 *                 associated with the ASE ID sent by the server.
 	 * @param rsp_code Response code.
 	 * @param reason   Reason code.
 	 */
@@ -1166,7 +1169,8 @@ struct bt_bap_unicast_client_cb {
 	 * only be called if the stream supplied to bt_bap_stream_stop() is
 	 * for a @ref BT_AUDIO_DIR_SOURCE endpoint.
 	 *
-	 * @param stream   Stream the operation was performed on.
+	 * @param stream   Stream the operation was performed on. May be NULL if there is no stream
+	 *                 associated with the ASE ID sent by the server.
 	 * @param rsp_code Response code.
 	 * @param reason   Reason code.
 	 */
@@ -1178,7 +1182,8 @@ struct bt_bap_unicast_client_cb {
 	 *
 	 * Called when the disable operation is completed on the server.
 	 *
-	 * @param stream   Stream the operation was performed on.
+	 * @param stream   Stream the operation was performed on. May be NULL if there is no stream
+	 *                 associated with the ASE ID sent by the server.
 	 * @param rsp_code Response code.
 	 * @param reason   Reason code.
 	 */
@@ -1190,7 +1195,8 @@ struct bt_bap_unicast_client_cb {
 	 *
 	 * Called when the metadata operation is completed on the server.
 	 *
-	 * @param stream   Stream the operation was performed on.
+	 * @param stream   Stream the operation was performed on. May be NULL if there is no stream
+	 *                 associated with the ASE ID sent by the server.
 	 * @param rsp_code Response code.
 	 * @param reason   Reason code.
 	 */
@@ -1202,7 +1208,8 @@ struct bt_bap_unicast_client_cb {
 	 *
 	 * Called when the release operation is completed on the server.
 	 *
-	 * @param stream   Stream the operation was performed on.
+	 * @param stream   Stream the operation was performed on. May be NULL if there is no stream
+	 *                 associated with the ASE ID sent by the server.
 	 * @param rsp_code Response code.
 	 * @param reason   Reason code.
 	 */

subsys/bluetooth/audio/ascs.c

@@ -891,7 +891,7 @@ static void ascs_cp_rsp_add(uint8_t id, uint8_t code, uint8_t reason)
 	 */
 	case BT_BAP_ASCS_RSP_CODE_NOT_SUPPORTED:
 	case BT_BAP_ASCS_RSP_CODE_INVALID_LENGTH:
-		rsp->num_ase = 0xff;
+		rsp->num_ase = BT_ASCS_UNSUPP_OR_LENGTH_ERR_NUM_ASE;
 		break;
 	default:
 		rsp->num_ase++;

subsys/bluetooth/audio/ascs_internal.h

@@ -9,6 +9,11 @@
 
 #define BT_ASCS_ASE_ID_NONE              0x00
 
+/* The number of ASEs in the notification when the opcode is unsupported or the length of the
+ * control point write request is incorrect
+ */
+#define BT_ASCS_UNSUPP_OR_LENGTH_ERR_NUM_ASE 0xFFU
+
 /* Transport QoS Packing */
 #define BT_ASCS_QOS_PACKING_SEQ          0x00
 #define BT_ASCS_QOS_PACKING_INT          0x01

subsys/bluetooth/audio/bap_unicast_client.c

@@ -1330,6 +1330,13 @@ static uint8_t unicast_client_cp_notify(struct bt_conn *conn,
 
 	rsp = net_buf_simple_pull_mem(&buf, sizeof(*rsp));
 
+	if (rsp->num_ase == BT_ASCS_UNSUPP_OR_LENGTH_ERR_NUM_ASE) {
+		/* This is a special case where num_ase == BT_ASCS_UNSUPP_OR_LENGTH_ERR_NUM_ASE
+		 * but really there is only one ASE response
+		 */
+		rsp->num_ase = 1U;
+	}
+
 	for (uint8_t i = 0U; i < rsp->num_ase; i++) {
 		struct bt_bap_unicast_client_ep *client_ep;
 		struct bt_ascs_cp_ase_rsp *ase_rsp;
@@ -1355,11 +1362,8 @@ static uint8_t unicast_client_cp_notify(struct bt_conn *conn,
 		stream = audio_stream_by_ep_id(conn, ase_rsp->id);
 		if (stream == NULL) {
 			LOG_DBG("Could not find stream by id %u", ase_rsp->id);
-			continue;
 		}
 
-		client_ep = CONTAINER_OF(stream->ep, struct bt_bap_unicast_client_ep, ep);
-
 		switch (rsp->op) {
 		case BT_ASCS_CONFIG_OP:
 			if (unicast_client_cbs->config != NULL) {
@@ -1398,9 +1402,14 @@ static uint8_t unicast_client_cp_notify(struct bt_conn *conn,
 			}
 			break;
 		case BT_ASCS_RELEASE_OP:
-			if (client_ep->release_requested) {
-				/* Set to false to only handle the callback here */
-				client_ep->release_requested = false;
+			if (stream != NULL) {
+				client_ep = CONTAINER_OF(stream->ep,
+							 struct bt_bap_unicast_client_ep, ep);
+
+				if (client_ep->release_requested) {
+					/* Set to false to only handle the callback here */
+					client_ep->release_requested = false;
+				}
 			}
 
 			if (unicast_client_cbs->release != NULL) {