bluetooth: host: Allow concurrent advertising with multiple ids

include/bluetooth/bluetooth.h

@@ -537,9 +537,6 @@ struct bt_le_adv_param {
 	 *       enabled or not supported by the controller it is not possible
 	 *       to scan and advertise simultaneously using two different
 	 *       random addresses.
-	 *
-	 * @note It is not possible to have multiple connectable advertising
-	 *       sets advertising simultaneously using different identities.
 	 */
 	uint8_t  id;
 

subsys/bluetooth/host/adv.c

@@ -1553,6 +1553,26 @@ void bt_hci_le_adv_set_terminated(struct net_buf *buf)
 	adv = bt_adv_lookup_handle(evt->adv_handle);
 	conn_handle = sys_le16_to_cpu(evt->conn_handle);
 
+#if (CONFIG_BT_ID_MAX > 1) && (CONFIG_BT_EXT_ADV_MAX_ADV_SET > 1)
+	bt_dev.adv_conn_id = adv->id;
+	for (int i = 0; i < ARRAY_SIZE(bt_dev.cached_conn_complete); i++) {
+		if (bt_dev.cached_conn_complete[i].valid &&
+		    bt_dev.cached_conn_complete[i].evt.handle == evt->conn_handle) {
+			if (atomic_test_bit(adv->flags, BT_ADV_ENABLED)) {
+				/* Process the cached connection complete event
+				 * now that the corresponding advertising set is known.
+				 *
+				 * If the advertiser has been stopped before the connection
+				 * complete event has been raised to the application, we
+				 * discard the event.
+				 */
+				bt_hci_le_enh_conn_complete(&bt_dev.cached_conn_complete[i].evt);
+			}
+			bt_dev.cached_conn_complete[i].valid = false;
+		}
+	}
+#endif
+
 	BT_DBG("status 0x%02x adv_handle %u conn_handle 0x%02x num %u",
 	       evt->status, evt->adv_handle, conn_handle,
 	       evt->num_completed_ext_adv_evts);

subsys/bluetooth/host/hci_core.c

@@ -1042,6 +1042,37 @@ static void le_conn_complete_adv_timeout(void)
 }
 
 static void enh_conn_complete(struct bt_hci_evt_le_enh_conn_complete *evt)
+{
+#if (CONFIG_BT_ID_MAX > 1) && (CONFIG_BT_EXT_ADV_MAX_ADV_SET > 1)
+	if (IS_ENABLED(CONFIG_BT_PERIPHERAL) &&
+		evt->role == BT_HCI_ROLE_SLAVE &&
+		evt->status == BT_HCI_ERR_SUCCESS &&
+		(IS_ENABLED(CONFIG_BT_EXT_ADV) &&
+				BT_FEAT_LE_EXT_ADV(bt_dev.le.features))) {
+
+		/* Cache the connection complete event. Process it later.
+		 * See bt_dev.cached_conn_complete.
+		 */
+		for (int i = 0; i < ARRAY_SIZE(bt_dev.cached_conn_complete); i++) {
+			if (!bt_dev.cached_conn_complete[i].valid) {
+				(void)memcpy(&bt_dev.cached_conn_complete[i].evt,
+					evt,
+					sizeof(struct bt_hci_evt_le_enh_conn_complete));
+				bt_dev.cached_conn_complete[i].valid = true;
+				return;
+			}
+		}
+
+		__ASSERT(false, "No more cache entries available."
+				"This should not happen by design");
+
+		return;
+	}
+#endif
+	bt_hci_le_enh_conn_complete(evt);
+}
+
+void bt_hci_le_enh_conn_complete(struct bt_hci_evt_le_enh_conn_complete *evt)
 {
 	uint16_t handle = sys_le16_to_cpu(evt->handle);
 	bt_addr_le_t peer_addr, id_addr;

subsys/bluetooth/host/hci_core.h

@@ -244,6 +244,22 @@ struct bt_dev {
 #else
 	/* Pointer to reserved advertising set */
 	struct bt_le_ext_adv    *adv;
+#if (CONFIG_BT_ID_MAX > 1) && (CONFIG_BT_EXT_ADV_MAX_ADV_SET > 1)
+	/* When supporting multiple concurrent connectable advertising sets
+	 * with multiple identities, we need to know the identity of
+	 * the terminating advertising set to identify the connection object.
+	 * The identity of the advertising set is determined by its
+	 * advertising handle, which is part of the
+	 * LE Set Advertising Set Terminated event which is always sent
+	 * _after_ the LE Enhanced Connection complete event.
+	 * Therefore we need cache this event until its identity is known.
+	 */
+	struct {
+		bool valid;
+		struct bt_hci_evt_le_enh_conn_complete evt;
+	} cached_conn_complete[MIN(CONFIG_BT_MAX_CONN,
+				CONFIG_BT_EXT_ADV_MAX_ADV_SET)];
+#endif
 #endif
 	/* Current local Random Address */
 	bt_addr_le_t            random_addr;
@@ -386,6 +402,9 @@ void bt_hci_auth_complete(struct net_buf *buf);
 void bt_hci_evt_le_pkey_complete(struct net_buf *buf);
 void bt_hci_evt_le_dhkey_complete(struct net_buf *buf);
 
+/* Common HCI event handlers */
+void bt_hci_le_enh_conn_complete(struct bt_hci_evt_le_enh_conn_complete *evt);
+
 /* Scan HCI event handlers */
 void bt_hci_le_adv_report(struct net_buf *buf);
 void bt_hci_le_scan_timeout(struct net_buf *buf);

tests/bluetooth/bsim_bt/bsim_test_advx/prj.conf

@@ -11,3 +11,6 @@ CONFIG_BT_PER_ADV_SYNC=y
 CONFIG_BT_CTLR_ADV_EXT=y
 CONFIG_BT_CTLR_ADV_PERIODIC=y
 CONFIG_BT_CTLR_SYNC_PERIODIC=y
+
+CONFIG_BT_ID_MAX=2
+CONFIG_BT_EXT_ADV_MAX_ADV_SET=2