Bluetooth: BAP: SD: Remove address lookups

Remove lookups in the Scan Delegator that relates to
the advertiser address. The reason for this, is that the
address is not considered a unique value for receive states,
since the address may change over time in the case of (N)RPAs.
Instead we shall rely exclusively on the address type, the sid
and the broadcast ID.

The implementation of the Scan Delegator and Broadcast Sink
has been updated to not use addresses for lookups anymore,
and there has been a minor API modification to set the
PA sync state as part of bt_bap_scan_delegator_add_src
as the higher layers are better suited to handle the
PA Sync state.

Signed-off-by: Emil Gydesen <[email protected]>

Author: Thalley

include/zephyr/bluetooth/audio/bap.h

@@ -2661,8 +2661,6 @@ int bt_bap_scan_delegator_unregister(void);
  *
  * @param src_id    The source id used to identify the receive state.
  * @param pa_state  The Periodic Advertising sync state to set.
- *                  BT_BAP_PA_STATE_NOT_SYNCED and BT_BAP_PA_STATE_SYNCED is
- *                  not necessary to provide, as they are handled internally.
  *
  * @return int    Error value. 0 on success, errno on fail.
  */
@@ -2688,6 +2686,14 @@ struct bt_bap_scan_delegator_add_src_param {
 	/** Advertiser SID */
 	uint8_t sid;
 
+	/**
+	 * @brief Periodic Advertising sync state
+	 *
+	 * This will typically be either @ref BT_BAP_PA_STATE_NOT_SYNCED or
+	 * @ref BT_BAP_PA_STATE_SYNCED.
+	 */
+	enum bt_bap_pa_state pa_state;
+
 	/** The broadcast isochronous group encryption state */
 	enum bt_bap_big_enc_state encrypt_state;
 

subsys/bluetooth/audio/bap_broadcast_sink.c

@@ -70,8 +70,8 @@ static struct bt_bap_scan_delegator_mod_src_param mod_src_param;
 
 static void broadcast_sink_cleanup(struct bt_bap_broadcast_sink *sink);
 
-static bool find_recv_state_by_sink_cb(const struct bt_bap_scan_delegator_recv_state *recv_state,
-				       void *user_data)
+static bool find_recv_state_by_src_id_cb(const struct bt_bap_scan_delegator_recv_state *recv_state,
+					 void *user_data)
 {
 	const struct bt_bap_broadcast_sink *sink = user_data;
 
@@ -83,34 +83,35 @@ static bool find_recv_state_by_sink_cb(const struct bt_bap_scan_delegator_recv_s
 	return false;
 }
 
-static bool find_recv_state_by_pa_sync_cb(const struct bt_bap_scan_delegator_recv_state *recv_state,
-					  void *user_data)
+static bool
+find_recv_state_by_sink_fields_cb(const struct bt_bap_scan_delegator_recv_state *recv_state,
+				  void *user_data)
 {
-	struct bt_le_per_adv_sync *sync = user_data;
+	const struct bt_bap_broadcast_sink *sink = user_data;
 	struct bt_le_per_adv_sync_info sync_info;
 	int err;
 
-	err = bt_le_per_adv_sync_get_info(sync, &sync_info);
+	err = bt_le_per_adv_sync_get_info(sink->pa_sync, &sync_info);
 	if (err != 0) {
 		LOG_DBG("Failed to get sync info: %d", err);
 
 		return false;
 	}
 
-	if (bt_addr_le_eq(&recv_state->addr, &sync_info.addr) &&
-	    recv_state->adv_sid == sync_info.sid) {
-		return true;
-	}
-
-	return false;
+	/* BAP 6.5.4 states that the combined Source_Address_Type, Source_Adv_SID, and Broadcast_ID
+	 * fields are what makes a receive state unique.
+	 */
+	return recv_state->addr.type == sync_info.addr.type &&
+	       recv_state->adv_sid == sync_info.sid &&
+	       recv_state->broadcast_id == sink->broadcast_id;
 };
 
 static void update_recv_state_big_synced(const struct bt_bap_broadcast_sink *sink)
 {
 	const struct bt_bap_scan_delegator_recv_state *recv_state;
 	int err;
 
-	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_sink_cb, (void *)sink);
+	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_src_id_cb, (void *)sink);
 	if (recv_state == NULL) {
 		LOG_WRN("Failed to find receive state for sink %p", sink);
 
@@ -156,7 +157,7 @@ static void update_recv_state_big_cleared(const struct bt_bap_broadcast_sink *si
 	bool sink_is_streaming = false;
 	int err;
 
-	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_sink_cb, (void *)sink);
+	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_src_id_cb, (void *)sink);
 	if (recv_state == NULL) {
 		/* This is likely due to the receive state being removed while we are BIG synced */
 		LOG_DBG("Could not find receive state for sink %p", sink);
@@ -489,6 +490,8 @@ static void broadcast_sink_add_src(struct bt_bap_broadcast_sink *sink)
 
 	bt_addr_le_copy(&add_src_param.addr, &sync_info.addr);
 	add_src_param.sid = sync_info.sid;
+	/* When a broadcast sink is created we always assume the PA sync provided is synced */
+	add_src_param.pa_state = BT_BAP_PA_STATE_SYNCED;
 	add_src_param.broadcast_id = sink->broadcast_id;
 	/* Will be updated when we receive the BASE */
 	add_src_param.encrypt_state = BT_BAP_BIG_ENC_STATE_NO_ENC;
@@ -542,7 +545,7 @@ static void update_recv_state_base(const struct bt_bap_broadcast_sink *sink,
 	const struct bt_bap_scan_delegator_recv_state *recv_state;
 	int err;
 
-	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_sink_cb, (void *)sink);
+	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_src_id_cb, (void *)sink);
 	if (recv_state == NULL) {
 		LOG_WRN("Failed to find receive state for sink %p", sink);
 
@@ -745,12 +748,23 @@ static void pa_recv(struct bt_le_per_adv_sync *sync,
 	bt_data_parse(buf, pa_decode_base, (void *)sink);
 }
 
+static void pa_synced_cb(struct bt_le_per_adv_sync *sync,
+			 struct bt_le_per_adv_sync_synced_info *info)
+{
+	struct bt_bap_broadcast_sink *sink = broadcast_sink_get_by_pa(sync);
+
+	if (sink != NULL) {
+		bt_bap_scan_delegator_set_pa_state(sink->bass_src_id, BT_BAP_PA_STATE_SYNCED);
+	}
+}
+
 static void pa_term_cb(struct bt_le_per_adv_sync *sync,
 		       const struct bt_le_per_adv_sync_term_info *info)
 {
 	struct bt_bap_broadcast_sink *sink = broadcast_sink_get_by_pa(sync);
 
 	if (sink != NULL) {
+		bt_bap_scan_delegator_set_pa_state(sink->bass_src_id, BT_BAP_PA_STATE_NOT_SYNCED);
 		sink->pa_sync = NULL;
 		sink->base_size = 0U;
 	}
@@ -763,7 +777,7 @@ static void update_recv_state_encryption(const struct bt_bap_broadcast_sink *sin
 
 	__ASSERT(sink->big == NULL, "Encryption state shall not be updated while synced");
 
-	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_sink_cb, (void *)sink);
+	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_src_id_cb, (void *)sink);
 	if (recv_state == NULL) {
 		LOG_WRN("Failed to find receive state for sink %p", sink);
 
@@ -1044,6 +1058,7 @@ int bt_bap_broadcast_sink_create(struct bt_le_per_adv_sync *pa_sync, uint32_t br
 {
 	const struct bt_bap_scan_delegator_recv_state *recv_state;
 	struct bt_bap_broadcast_sink *sink;
+	int err;
 
 	CHECKIF(pa_sync == NULL) {
 		LOG_DBG("pa_sync is NULL");
@@ -1073,8 +1088,8 @@ int bt_bap_broadcast_sink_create(struct bt_le_per_adv_sync *pa_sync, uint32_t br
 	sink->broadcast_id = broadcast_id;
 	sink->pa_sync = pa_sync;
 
-	recv_state = bt_bap_scan_delegator_find_state(find_recv_state_by_pa_sync_cb,
-						      (void *)pa_sync);
+	recv_state =
+		bt_bap_scan_delegator_find_state(find_recv_state_by_sink_fields_cb, (void *)sink);
 	if (recv_state == NULL) {
 		broadcast_sink_add_src(sink);
 	} else {
@@ -1088,8 +1103,24 @@ int bt_bap_broadcast_sink_create(struct bt_le_per_adv_sync *pa_sync, uint32_t br
 		}
 
 		sink->bass_src_id = recv_state->src_id;
+		if (recv_state->pa_sync_state != BT_BAP_PA_STATE_SYNCED) {
+			/* When a broadcast sink is created we always assume the PA sync provided is
+			 * synced
+			 */
+			err = bt_bap_scan_delegator_set_pa_state(sink->bass_src_id,
+								 BT_BAP_PA_STATE_SYNCED);
+			if (err != 0) {
+				LOG_DBG("Failed to set PA state: %d", err);
+
+				broadcast_sink_cleanup(sink);
+
+				return err;
+			}
+		}
+
 		atomic_set_bit(sink->flags, BT_BAP_BROADCAST_SINK_FLAG_SRC_ID_VALID);
 	}
+
 	atomic_set_bit(sink->flags, BT_BAP_BROADCAST_SINK_FLAG_INITIALIZED);
 
 	*out_sink = sink;
@@ -1432,6 +1463,7 @@ int bt_bap_broadcast_sink_delete(struct bt_bap_broadcast_sink *sink)
 static int broadcast_sink_init(void)
 {
 	static struct bt_le_per_adv_sync_cb cb = {
+		.synced = pa_synced_cb,
 		.recv = pa_recv,
 		.biginfo = biginfo_recv,
 		.term = pa_term_cb,