Bluetooth: CAP: Add ep conn check in unicast audio start

doc/releases/release-notes-4.3.rst

@@ -114,6 +114,7 @@ New APIs and options
     * :c:struct:`bt_bap_stream` now contains an ``iso`` field as a reference to the ISO channel
     * :c:func:`bt_bap_unicast_group_get_info`
     * :c:func:`bt_cap_unicast_group_get_info`
+    * :c:func:`bt_bap_ep_get_conn`
 
   * Host
 

include/zephyr/bluetooth/audio/bap.h

@@ -882,6 +882,21 @@ struct bt_bap_ep_info {
  */
 int bt_bap_ep_get_info(const struct bt_bap_ep *ep, struct bt_bap_ep_info *info);
 
+/**
+ * @brief Get the pointer to the ACL connection of an endpoint
+ *
+ * The caller gets a new reference to the connection object, if not NULL, which must be
+ * released with bt_conn_unref() once done using the object.
+ *
+ * @param ep The endpoint to get the ACL connection of
+ *
+ * @return The ACL connection pointer.
+ *         Will always be NULL for broadcast endpoints.
+ *         Will be NULL for Unicast Server endpoints if the endpoint is not configured by a client.
+ *         Will be NULL for Unicast Client endpoints if @p does not match a discovered endpoint.
+ */
+struct bt_conn *bt_bap_ep_get_conn(const struct bt_bap_ep *ep);
+
 /**
  * @brief Basic Audio Profile stream structure.
  *
@@ -1967,17 +1982,24 @@ struct bt_bap_unicast_client_cb {
 /**
  * @brief Register unicast client callbacks.
  *
- * Only one callback structure can be registered, and attempting to
- * registering more than one will result in an error.
- *
- * @param cb  Unicast client callback structure.
+ * @param cb  Unicast client callback structure to register.
  *
  * @retval 0 Success
  * @retval -EINVAL @p cb is NULL.
  * @retval -EEXIST @p cb is already registered.
  */
 int bt_bap_unicast_client_register_cb(struct bt_bap_unicast_client_cb *cb);
 
+/**
+ * @brief Unregister unicast client callbacks.
+ *
+ * @param cb  Unicast client callback structure to unregister.
+ *
+ * @retval 0 Success
+ * @retval -EINVAL @p cb is NULL or @p cb was not registered
+ */
+int bt_bap_unicast_client_unregister_cb(struct bt_bap_unicast_client_cb *cb);
+
 /**
  * @brief Discover remote capabilities and endpoints
  *

subsys/bluetooth/audio/ascs.c

@@ -3259,4 +3259,16 @@ int bt_ascs_unregister(void)
 	return err;
 }
 
+struct bt_conn *bt_ascs_ep_get_conn(const struct bt_bap_ep *ep)
+{
+	struct bt_ascs_ase *ase = CONTAINER_OF(ep, struct bt_ascs_ase, ep);
+
+	__ASSERT_NO_MSG(bt_ascs_has_ep(ep));
+
+	if (ase->conn == NULL) {
+		return NULL;
+	}
+
+	return bt_conn_ref(ase->conn);
+}
 #endif /* BT_BAP_UNICAST_SERVER */

subsys/bluetooth/audio/ascs_internal.h

@@ -364,5 +364,6 @@ void bt_ascs_foreach_ep(struct bt_conn *conn, bt_bap_ep_func_t func, void *user_
 
 int bt_ascs_register(uint8_t snk_cnt, uint8_t src_cnt);
 int bt_ascs_unregister(void);
+struct bt_conn *bt_ascs_ep_get_conn(const struct bt_bap_ep *ep);
 
 #endif /* BT_ASCS_INTERNAL_H */

subsys/bluetooth/audio/bap_internal.h

@@ -147,3 +147,5 @@ bool bt_bap_broadcast_sink_has_ep(const struct bt_bap_ep *ep);
 bool bt_bap_broadcast_source_has_ep(const struct bt_bap_ep *ep);
 bool bt_bap_unicast_client_has_ep(const struct bt_bap_ep *ep);
 bool bt_bap_unicast_server_has_ep(const struct bt_bap_ep *ep);
+struct bt_conn *bt_bap_unicast_client_ep_get_conn(const struct bt_bap_ep *ep);
+struct bt_conn *bt_bap_unicast_server_ep_get_conn(const struct bt_bap_ep *ep);

subsys/bluetooth/audio/bap_stream.c

@@ -173,6 +173,31 @@ int bt_bap_ep_get_info(const struct bt_bap_ep *ep, struct bt_bap_ep_info *info)
 	return 0;
 }
 
+struct bt_conn *bt_bap_ep_get_conn(const struct bt_bap_ep *ep)
+{
+	struct bt_conn *conn;
+
+	if (ep == NULL) {
+		LOG_DBG("ep is NULL");
+
+		return NULL;
+	}
+
+	if ((IS_ENABLED(CONFIG_BT_BAP_BROADCAST_SOURCE) && bt_bap_broadcast_source_has_ep(ep)) ||
+	    (IS_ENABLED(CONFIG_BT_BAP_BROADCAST_SINK) && bt_bap_broadcast_sink_has_ep(ep))) {
+		conn = NULL;
+	} else if (IS_ENABLED(CONFIG_BT_BAP_UNICAST_CLIENT) && bt_bap_unicast_client_has_ep(ep)) {
+		conn = bt_bap_unicast_client_ep_get_conn(ep);
+	} else if (IS_ENABLED(CONFIG_BT_BAP_UNICAST_SERVER) && bt_bap_unicast_server_has_ep(ep)) {
+		conn = bt_bap_unicast_server_ep_get_conn(ep);
+	} else {
+		LOG_DBG("Invalid endpoint %p", ep);
+		conn = NULL;
+	}
+
+	return conn;
+}
+
 enum bt_bap_ascs_reason bt_audio_verify_qos(const struct bt_bap_qos_cfg *qos)
 {
 	if (qos->interval < BT_ISO_SDU_INTERVAL_MIN ||

subsys/bluetooth/audio/bap_unicast_client.c

@@ -460,6 +460,41 @@ bool bt_bap_unicast_client_has_ep(const struct bt_bap_ep *ep)
 	return false;
 }
 
+struct bt_conn *bt_bap_unicast_client_ep_get_conn(const struct bt_bap_ep *ep)
+{
+	for (size_t i = 0U; i < ARRAY_SIZE(uni_cli_insts); i++) {
+#if CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SNK_COUNT > 0
+		if (PART_OF_ARRAY(uni_cli_insts[i].snks, ep)) {
+			ARRAY_FOR_EACH_PTR(uni_cli_insts[i].snks, client_ep) {
+				if (&client_ep->ep == ep) {
+					if (client_ep->handle == BAP_HANDLE_UNUSED) {
+						return NULL;
+					}
+
+					return bt_conn_lookup_index((uint8_t)i);
+				}
+			}
+		}
+#endif /* CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SNK_COUNT > 0 */
+
+#if CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SRC_COUNT > 0
+		if (PART_OF_ARRAY(uni_cli_insts[i].srcs, ep)) {
+			ARRAY_FOR_EACH_PTR(uni_cli_insts[i].srcs, client_ep) {
+				if (&client_ep->ep == ep) {
+					if (client_ep->handle == BAP_HANDLE_UNUSED) {
+						return NULL;
+					}
+
+					return bt_conn_lookup_index((uint8_t)i);
+				}
+			}
+		}
+#endif /* CONFIG_BT_BAP_UNICAST_CLIENT_ASE_SRC_COUNT > 0 */
+	}
+
+	return NULL;
+}
+
 static void unicast_client_ep_init(struct bt_bap_ep *ep, uint16_t handle, uint8_t dir)
 {
 	struct bt_bap_unicast_client_ep *client_ep;
@@ -4684,3 +4719,18 @@ int bt_bap_unicast_client_register_cb(struct bt_bap_unicast_client_cb *cb)
 
 	return 0;
 }
+
+int bt_bap_unicast_client_unregister_cb(struct bt_bap_unicast_client_cb *cb)
+{
+	if (cb == NULL) {
+		LOG_DBG("cb was NULL");
+		return -EINVAL;
+	}
+
+	if (!sys_slist_find_and_remove(&unicast_client_cbs, &cb->_node)) {
+		LOG_DBG("cb was not registered");
+		return -EALREADY;
+	}
+
+	return 0;
+}

subsys/bluetooth/audio/bap_unicast_server.c

@@ -227,3 +227,8 @@ bool bt_bap_unicast_server_has_ep(const struct bt_bap_ep *ep)
 {
 	return bt_ascs_has_ep(ep);
 }
+
+struct bt_conn *bt_bap_unicast_server_ep_get_conn(const struct bt_bap_ep *ep)
+{
+	return bt_ascs_ep_get_conn(ep);
+}

subsys/bluetooth/audio/cap_initiator.c

@@ -1158,9 +1158,11 @@ bool bt_cap_initiator_valid_unicast_audio_start_param(
 		const union bt_cap_set_member *member = &stream_param->member;
 		const struct bt_cap_stream *cap_stream = stream_param->stream;
 		const struct bt_audio_codec_cfg *codec_cfg = stream_param->codec_cfg;
+		const struct bt_bap_ep *ep = stream_param->ep;
 		const struct bt_bap_stream *bap_stream;
 		const struct bt_conn *member_conn =
 			bt_cap_common_get_member_conn(param->type, member);
+		struct bt_conn *ep_conn;
 
 		if (member == NULL) {
 			LOG_DBG("param->members[%zu] is NULL", i);
@@ -1182,11 +1184,26 @@ bool bt_cap_initiator_valid_unicast_audio_start_param(
 			return false;
 		}
 
-		CHECKIF(stream_param->ep == NULL) {
+		if (ep == NULL) {
 			LOG_DBG("param->stream_params[%zu].ep is NULL", i);
 			return false;
 		}
 
+		ep_conn = bt_bap_ep_get_conn(ep);
+		if (ep_conn == NULL) {
+			LOG_DBG("param->stream_params[%zu].ep is invalid", i);
+			return false;
+		}
+		if (ep_conn != member_conn) {
+			LOG_DBG("param->stream_params[%zu].ep conn %p does not match "
+				"param->members[%zu] %p",
+				i, ep_conn, i, member_conn);
+			bt_conn_unref(ep_conn);
+
+			return false;
+		}
+		bt_conn_unref(ep_conn);
+
 		CHECKIF(member == NULL) {
 			LOG_DBG("param->stream_params[%zu].member is NULL", i);
 			return false;

tests/bluetooth/audio/cap_initiator/include/test_common.h

@@ -1,10 +1,11 @@
 /* test_common.h */
 
 /*
- * Copyright (c) 2024 Nordic Semiconductor ASA
+ * Copyright (c) 2024-2025 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
+#include <stdint.h>
 
 #include <zephyr/bluetooth/audio/bap.h>
 #include <zephyr/bluetooth/audio/bap_lc3_preset.h>
@@ -14,7 +15,7 @@
 void test_mocks_init(void);
 void test_mocks_cleanup(void);
 
-void test_conn_init(struct bt_conn *conn);
+void test_conn_init(struct bt_conn *conn, uint8_t index);
 
 void test_unicast_set_state(struct bt_cap_stream *cap_stream, struct bt_conn *conn,
 			    struct bt_bap_ep *ep, struct bt_bap_lc3_preset *preset,

tests/bluetooth/audio/cap_initiator/src/main.c

@@ -43,7 +43,7 @@ struct cap_initiator_test_suite_fixture {
 static void cap_initiator_test_suite_fixture_init(struct cap_initiator_test_suite_fixture *fixture)
 {
 	for (size_t i = 0; i < ARRAY_SIZE(fixture->conns); i++) {
-		test_conn_init(&fixture->conns[i]);
+		test_conn_init(&fixture->conns[i], i);
 	}
 }
 

tests/bluetooth/audio/cap_initiator/src/test_common.c

@@ -1,11 +1,13 @@
 /* test_common.c - common procedures for unit test of CAP initiator */
 
 /*
- * Copyright (c) 2024 Nordic Semiconductor ASA
+ * Copyright (c) 2024-2025 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <stdint.h>
+
 #include <zephyr/bluetooth/audio/bap.h>
 #include <zephyr/bluetooth/audio/bap_lc3_preset.h>
 #include <zephyr/bluetooth/audio/cap.h>
@@ -32,9 +34,9 @@ void test_mocks_cleanup(void)
 	mock_cap_initiator_cleanup();
 }
 
-void test_conn_init(struct bt_conn *conn)
+void test_conn_init(struct bt_conn *conn, uint8_t index)
 {
-	conn->index = 0;
+	conn->index = index;
 	conn->info.type = BT_CONN_TYPE_LE;
 	conn->info.role = BT_CONN_ROLE_CENTRAL;
 	conn->info.state = BT_CONN_STATE_CONNECTED;