| /* |
| * Copyright (C) 2019 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. |
| */ |
| package com.android.car.trust; |
| |
| import static android.bluetooth.BluetoothProfile.GATT_SERVER; |
| |
| import android.bluetooth.BluetoothAdapter; |
| import android.bluetooth.BluetoothDevice; |
| import android.bluetooth.BluetoothGatt; |
| import android.bluetooth.BluetoothGattCallback; |
| import android.bluetooth.BluetoothGattCharacteristic; |
| import android.bluetooth.BluetoothGattServer; |
| import android.bluetooth.BluetoothGattServerCallback; |
| import android.bluetooth.BluetoothGattService; |
| import android.bluetooth.BluetoothManager; |
| import android.bluetooth.BluetoothProfile; |
| import android.bluetooth.le.AdvertiseCallback; |
| import android.bluetooth.le.AdvertiseData; |
| import android.bluetooth.le.AdvertiseSettings; |
| import android.bluetooth.le.BluetoothLeAdvertiser; |
| import android.content.Context; |
| import android.content.pm.PackageManager; |
| import android.os.Handler; |
| import android.util.Log; |
| |
| import androidx.annotation.Nullable; |
| |
| import com.android.car.Utils; |
| |
| import java.util.UUID; |
| |
| /** |
| * A generic class that manages BLE operations like start/stop advertising, notifying connects/ |
| * disconnects and reading/writing values to GATT characteristics. |
| * |
| * TODO(b/123248433) This could move to a separate comms library. |
| */ |
| public abstract class BleManager { |
| private static final String TAG = BleManager.class.getSimpleName(); |
| |
| private static final int BLE_RETRY_LIMIT = 5; |
| private static final int BLE_RETRY_INTERVAL_MS = 1000; |
| |
| // https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth |
| // .service.generic_access.xml |
| private static final UUID GENERIC_ACCESS_PROFILE_UUID = |
| UUID.fromString("00001800-0000-1000-8000-00805f9b34fb"); |
| //https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth |
| // .characteristic.gap.device_name.xml |
| private static final UUID DEVICE_NAME_UUID = |
| UUID.fromString("00002a00-0000-1000-8000-00805f9b34fb"); |
| |
| private final Handler mHandler = new Handler(); |
| |
| private final Context mContext; |
| private BluetoothManager mBluetoothManager; |
| private BluetoothLeAdvertiser mAdvertiser; |
| private BluetoothGattServer mGattServer; |
| private BluetoothGatt mBluetoothGatt; |
| private int mAdvertiserStartCount; |
| |
| BleManager(Context context) { |
| mContext = context; |
| } |
| |
| /** |
| * Starts the GATT server with the given {@link BluetoothGattService} and begins |
| * advertising. |
| * |
| * <p>It is possible that BLE service is still in TURNING_ON state when this method is invoked. |
| * Therefore, several retries will be made to ensure advertising is started. |
| * |
| * @param service {@link BluetoothGattService} that will be discovered by clients |
| * @param data {@link AdvertiseData} data to advertise |
| * @param advertiseCallback {@link AdvertiseCallback} callback for advertiser |
| */ |
| protected void startAdvertising(BluetoothGattService service, AdvertiseData data, |
| AdvertiseCallback advertiseCallback) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "startAdvertising: " + service.getUuid().toString()); |
| } |
| if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) { |
| Log.e(TAG, "System does not support BLE"); |
| return; |
| } |
| |
| // Only open one Gatt server. |
| if (mGattServer == null) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "Opening a new GATT Server"); |
| } |
| mBluetoothManager = (BluetoothManager) mContext.getSystemService( |
| Context.BLUETOOTH_SERVICE); |
| mGattServer = mBluetoothManager.openGattServer(mContext, mGattServerCallback); |
| |
| if (mGattServer == null) { |
| Log.e(TAG, "Gatt Server not created"); |
| return; |
| } |
| } |
| |
| mGattServer.clearServices(); |
| mGattServer.addService(service); |
| |
| AdvertiseSettings settings = new AdvertiseSettings.Builder() |
| .setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY) |
| .setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_HIGH) |
| .setConnectable(true) |
| .build(); |
| |
| mAdvertiserStartCount = 0; |
| startAdvertisingInternally(settings, data, advertiseCallback); |
| } |
| |
| private void startAdvertisingInternally(AdvertiseSettings settings, AdvertiseData data, |
| AdvertiseCallback advertiseCallback) { |
| if (BluetoothAdapter.getDefaultAdapter() != null) { |
| mAdvertiser = BluetoothAdapter.getDefaultAdapter().getBluetoothLeAdvertiser(); |
| } |
| |
| if (mAdvertiser != null) { |
| mAdvertiser.startAdvertising(settings, data, advertiseCallback); |
| mAdvertiserStartCount = 0; |
| } else if (mAdvertiserStartCount < BLE_RETRY_LIMIT) { |
| mHandler.postDelayed( |
| () -> startAdvertisingInternally(settings, data, advertiseCallback), |
| BLE_RETRY_INTERVAL_MS); |
| mAdvertiserStartCount += 1; |
| } else { |
| Log.e(TAG, "Cannot start BLE Advertisement. BT Adapter: " |
| + BluetoothAdapter.getDefaultAdapter() + " Advertise Retry count: " |
| + mAdvertiserStartCount); |
| } |
| } |
| |
| protected void stopAdvertising(AdvertiseCallback advertiseCallback) { |
| if (mAdvertiser != null) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "stopAdvertising: "); |
| } |
| mAdvertiser.stopAdvertising(advertiseCallback); |
| } |
| } |
| |
| /** |
| * Notifies the characteristic change via {@link BluetoothGattServer} |
| */ |
| protected void notifyCharacteristicChanged(BluetoothDevice device, |
| BluetoothGattCharacteristic characteristic, boolean confirm) { |
| if (mGattServer != null) { |
| mGattServer.notifyCharacteristicChanged(device, characteristic, confirm); |
| } |
| } |
| |
| /** |
| * Connect the Gatt server of the remote device to retrieve device name. |
| */ |
| protected final void retrieveDeviceName(BluetoothDevice device) { |
| mBluetoothGatt = device.connectGatt(getContext(), false, mGattCallback); |
| } |
| |
| protected Context getContext() { |
| return mContext; |
| } |
| |
| /** |
| * Cleans up the BLE GATT server state. |
| */ |
| void cleanup() { |
| // Stops the advertiser and GATT server. This needs to be done to avoid leaks |
| if (mAdvertiser != null) { |
| mAdvertiser.cleanup(); |
| } |
| |
| if (mGattServer != null) { |
| mGattServer.clearServices(); |
| try { |
| for (BluetoothDevice d : mBluetoothManager.getConnectedDevices(GATT_SERVER)) { |
| mGattServer.cancelConnection(d); |
| } |
| } catch (UnsupportedOperationException e) { |
| Log.e(TAG, "Error getting connected devices", e); |
| } finally { |
| stopGattServer(); |
| } |
| } |
| } |
| |
| /** |
| * Close the GATT Server |
| */ |
| void stopGattServer() { |
| if (mGattServer == null) { |
| return; |
| } |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "stopGattServer"); |
| } |
| if (mBluetoothGatt != null) { |
| mBluetoothGatt.disconnect(); |
| } |
| mGattServer.close(); |
| mGattServer = null; |
| } |
| |
| /** |
| * Triggered when the name of the remote device is retrieved. |
| * |
| * @param deviceName Name of the remote device. |
| */ |
| protected void onDeviceNameRetrieved(@Nullable String deviceName) { |
| } |
| |
| /** |
| * Triggered if a remote client has requested to change the MTU for a given connection. |
| * |
| * @param size The new MTU size. |
| */ |
| protected void onMtuSizeChanged(int size) { |
| } |
| |
| /** |
| * Triggered when a device (GATT client) connected. |
| * |
| * @param device Remote device that connected on BLE. |
| */ |
| protected void onRemoteDeviceConnected(BluetoothDevice device) { |
| } |
| |
| /** |
| * Triggered when a device (GATT client) disconnected. |
| * |
| * @param device Remote device that disconnected on BLE. |
| */ |
| protected void onRemoteDeviceDisconnected(BluetoothDevice device) { |
| } |
| |
| /** |
| * Triggered when this BleManager receives a write request from a remote |
| * device. Sub-classes should implement how to handle requests. |
| * <p> |
| * |
| * @see BluetoothGattServerCallback#onCharacteristicWriteRequest(BluetoothDevice, int, |
| * BluetoothGattCharacteristic, boolean, boolean, int, byte[]) |
| */ |
| protected abstract void onCharacteristicWrite(BluetoothDevice device, int requestId, |
| BluetoothGattCharacteristic characteristic, boolean preparedWrite, boolean |
| responseNeeded, int offset, byte[] value); |
| |
| /** |
| * Triggered when this BleManager receives a read request from a remote device. |
| * <p> |
| * |
| * @see BluetoothGattServerCallback#onCharacteristicReadRequest(BluetoothDevice, int, int, |
| * BluetoothGattCharacteristic) |
| */ |
| protected abstract void onCharacteristicRead(BluetoothDevice device, |
| int requestId, int offset, BluetoothGattCharacteristic characteristic); |
| |
| private final BluetoothGattServerCallback mGattServerCallback = |
| new BluetoothGattServerCallback() { |
| @Override |
| public void onConnectionStateChange(BluetoothDevice device, int status, |
| int newState) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "BLE Connection State Change: " + newState); |
| } |
| switch (newState) { |
| case BluetoothProfile.STATE_CONNECTED: |
| onRemoteDeviceConnected(device); |
| break; |
| case BluetoothProfile.STATE_DISCONNECTED: |
| onRemoteDeviceDisconnected(device); |
| break; |
| default: |
| Log.w(TAG, |
| "Connection state not connecting or disconnecting; ignoring: " |
| + newState); |
| } |
| } |
| |
| @Override |
| public void onServiceAdded(int status, BluetoothGattService service) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, |
| "Service added status: " + status + " uuid: " + service.getUuid()); |
| } |
| } |
| |
| @Override |
| public void onCharacteristicReadRequest(BluetoothDevice device, int requestId, |
| int offset, BluetoothGattCharacteristic characteristic) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "Read request for characteristic: " + characteristic.getUuid()); |
| } |
| |
| mGattServer.sendResponse(device, requestId, |
| BluetoothGatt.GATT_SUCCESS, offset, characteristic.getValue()); |
| onCharacteristicRead(device, requestId, offset, characteristic); |
| } |
| |
| @Override |
| public void onCharacteristicWriteRequest(BluetoothDevice device, int requestId, |
| BluetoothGattCharacteristic characteristic, boolean preparedWrite, |
| boolean responseNeeded, int offset, byte[] value) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "Write request for characteristic: " + characteristic.getUuid() |
| + "value: " + Utils.byteArrayToHexString(value)); |
| } |
| |
| mGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, |
| offset, value); |
| onCharacteristicWrite(device, requestId, characteristic, |
| preparedWrite, responseNeeded, offset, value); |
| } |
| |
| @Override |
| public void onMtuChanged(BluetoothDevice device, int mtu) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "onMtuChanged: " + mtu + " for device " + device.getAddress()); |
| } |
| onMtuSizeChanged(mtu); |
| } |
| |
| }; |
| |
| private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() { |
| @Override |
| public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "Gatt Connection State Change: " + newState); |
| } |
| switch (newState) { |
| case BluetoothProfile.STATE_CONNECTED: |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "Gatt connected"); |
| } |
| mBluetoothGatt.discoverServices(); |
| break; |
| case BluetoothProfile.STATE_DISCONNECTED: |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "Gatt Disconnected"); |
| } |
| break; |
| default: |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, |
| "Connection state not connecting or disconnecting; ignoring: " |
| + newState); |
| } |
| } |
| } |
| |
| @Override |
| public void onServicesDiscovered(BluetoothGatt gatt, int status) { |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "Gatt Services Discovered"); |
| } |
| BluetoothGattService gapService = mBluetoothGatt.getService( |
| GENERIC_ACCESS_PROFILE_UUID); |
| if (gapService == null) { |
| Log.e(TAG, "Generic Access Service is Null"); |
| return; |
| } |
| BluetoothGattCharacteristic deviceNameCharacteristic = gapService.getCharacteristic( |
| DEVICE_NAME_UUID); |
| if (deviceNameCharacteristic == null) { |
| Log.e(TAG, "Device Name Characteristic is Null"); |
| return; |
| } |
| mBluetoothGatt.readCharacteristic(deviceNameCharacteristic); |
| } |
| |
| @Override |
| public void onCharacteristicRead(BluetoothGatt gatt, |
| BluetoothGattCharacteristic characteristic, int status) { |
| if (status == BluetoothGatt.GATT_SUCCESS) { |
| String deviceName = characteristic.getStringValue(0); |
| if (Log.isLoggable(TAG, Log.DEBUG)) { |
| Log.d(TAG, "BLE Device Name: " + deviceName); |
| } |
| onDeviceNameRetrieved(deviceName); |
| } else { |
| Log.e(TAG, "Reading GAP Failed: " + status); |
| } |
| } |
| }; |
| } |