bluetooth: add aidl hal

* Copy from hardware/interfaces/bluetooth/aidl/default
  at 488942f82bd1bc9ad1cb65a02c71421dc3a6a3d6.

bluetooth/net_bluetooth_mgmt.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <unistd.h>
+
+namespace aidl::android::hardware::bluetooth::impl {
+
+class NetBluetoothMgmt {
+ public:
+  NetBluetoothMgmt() {}
+  ~NetBluetoothMgmt() {
+    ::close(rfkill_fd_);
+    ::close(bt_fd_);
+  }
+
+  int openHci(int hci_interface = 0);
+  void closeHci();
+
+ private:
+  int waitHciDev(int hci_interface);
+  int openRfkill();
+  int rfkill(int block);
+
+  // Index of the first rfkill device of type bluetooth.
+  int rfkill_bt_index_{-1};
+  // File descriptor opened to /dev/rfkill.
+  int rfkill_fd_{-1};
+  // File descriptor opened to the bluetooth user channel.
+  int bt_fd_{-1};
+};
+
+}  // namespace aidl::android::hardware::bluetooth::impl