Ram Periathiruvadi | de0ca08 | 2019-03-20 11:16:44 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2019 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package com.android.car.trust; |
| 17 | |
| 18 | import static android.bluetooth.BluetoothProfile.GATT_SERVER; |
| 19 | |
| 20 | import android.bluetooth.BluetoothAdapter; |
| 21 | import android.bluetooth.BluetoothDevice; |
| 22 | import android.bluetooth.BluetoothGatt; |
| 23 | import android.bluetooth.BluetoothGattCharacteristic; |
| 24 | import android.bluetooth.BluetoothGattServer; |
| 25 | import android.bluetooth.BluetoothGattServerCallback; |
| 26 | import android.bluetooth.BluetoothGattService; |
| 27 | import android.bluetooth.BluetoothManager; |
| 28 | import android.bluetooth.BluetoothProfile; |
| 29 | import android.bluetooth.le.AdvertiseCallback; |
| 30 | import android.bluetooth.le.AdvertiseData; |
| 31 | import android.bluetooth.le.AdvertiseSettings; |
| 32 | import android.bluetooth.le.BluetoothLeAdvertiser; |
| 33 | import android.content.Context; |
| 34 | import android.content.pm.PackageManager; |
| 35 | import android.os.Handler; |
| 36 | import android.os.ParcelUuid; |
| 37 | import android.util.Log; |
| 38 | |
| 39 | import com.android.car.Utils; |
| 40 | |
| 41 | /** |
| 42 | * A generic class that manages BLE operations like start/stop advertising, notifying connects/ |
| 43 | * disconnects and reading/writing values to GATT characteristics. |
| 44 | * |
| 45 | * TODO(b/123248433) This could move to a separate comms library. |
| 46 | */ |
| 47 | public abstract class BleManager { |
| 48 | private static final String TAG = BleManager.class.getSimpleName(); |
| 49 | |
| 50 | private static final int BLE_RETRY_LIMIT = 5; |
| 51 | private static final int BLE_RETRY_INTERVAL_MS = 1000; |
| 52 | |
| 53 | private final Handler mHandler = new Handler(); |
| 54 | |
| 55 | private final Context mContext; |
| 56 | private BluetoothManager mBluetoothManager; |
| 57 | private BluetoothLeAdvertiser mAdvertiser; |
| 58 | private BluetoothGattServer mGattServer; |
| 59 | private int mAdvertiserStartCount; |
| 60 | |
| 61 | BleManager(Context context) { |
| 62 | mContext = context; |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * Starts the GATT server with the given {@link BluetoothGattService} and begins |
| 67 | * advertising. |
| 68 | * |
| 69 | * <p>It is possible that BLE service is still in TURNING_ON state when this method is invoked. |
| 70 | * Therefore, several retries will be made to ensure advertising is started. |
| 71 | * |
| 72 | * @param service {@link BluetoothGattService} that will be discovered by clients |
| 73 | */ |
| 74 | protected void startAdvertising(BluetoothGattService service, |
| 75 | AdvertiseCallback advertiseCallback) { |
| 76 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 77 | Log.d(TAG, "startAdvertising: " + service.getUuid().toString()); |
| 78 | } |
| 79 | if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) { |
| 80 | Log.e(TAG, "System does not support BLE"); |
| 81 | return; |
| 82 | } |
| 83 | |
| 84 | // Only open one Gatt server. |
| 85 | if (mGattServer == null) { |
| 86 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 87 | Log.d(TAG, "Opening a new GATT Server"); |
| 88 | } |
| 89 | mBluetoothManager = (BluetoothManager) mContext.getSystemService( |
| 90 | Context.BLUETOOTH_SERVICE); |
| 91 | mGattServer = mBluetoothManager.openGattServer(mContext, mGattServerCallback); |
| 92 | |
| 93 | if (mGattServer == null) { |
| 94 | Log.e(TAG, "Gatt Server not created"); |
| 95 | return; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | mGattServer.clearServices(); |
| 100 | mGattServer.addService(service); |
| 101 | |
| 102 | AdvertiseSettings settings = new AdvertiseSettings.Builder() |
| 103 | .setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY) |
| 104 | .setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_HIGH) |
| 105 | .setConnectable(true) |
| 106 | .build(); |
| 107 | |
| 108 | AdvertiseData data = new AdvertiseData.Builder() |
| 109 | .setIncludeDeviceName(true) |
| 110 | .addServiceUuid(new ParcelUuid(service.getUuid())) |
| 111 | .build(); |
| 112 | |
| 113 | mAdvertiserStartCount = 0; |
| 114 | startAdvertisingInternally(settings, data, advertiseCallback); |
| 115 | } |
| 116 | |
| 117 | private void startAdvertisingInternally(AdvertiseSettings settings, AdvertiseData data, |
| 118 | AdvertiseCallback advertiseCallback) { |
Ram Periathiruvadi | f9eef49 | 2019-03-28 18:09:39 -0700 | [diff] [blame] | 119 | if (BluetoothAdapter.getDefaultAdapter() != null) { |
| 120 | mAdvertiser = BluetoothAdapter.getDefaultAdapter().getBluetoothLeAdvertiser(); |
| 121 | } |
| 122 | |
| 123 | if (mAdvertiser != null) { |
| 124 | mAdvertiser.startAdvertising(settings, data, advertiseCallback); |
| 125 | mAdvertiserStartCount = 0; |
| 126 | } else if (mAdvertiserStartCount < BLE_RETRY_LIMIT) { |
Ram Periathiruvadi | de0ca08 | 2019-03-20 11:16:44 -0700 | [diff] [blame] | 127 | mHandler.postDelayed( |
| 128 | () -> startAdvertisingInternally(settings, data, advertiseCallback), |
| 129 | BLE_RETRY_INTERVAL_MS); |
| 130 | mAdvertiserStartCount += 1; |
| 131 | } else { |
Ram Periathiruvadi | f9eef49 | 2019-03-28 18:09:39 -0700 | [diff] [blame] | 132 | Log.e(TAG, "Cannot start BLE Advertisement. BT Adapter: " |
| 133 | + BluetoothAdapter.getDefaultAdapter() + " Advertise Retry count: " |
| 134 | + mAdvertiserStartCount); |
Ram Periathiruvadi | de0ca08 | 2019-03-20 11:16:44 -0700 | [diff] [blame] | 135 | } |
| 136 | } |
| 137 | |
| 138 | protected void stopAdvertising(AdvertiseCallback advertiseCallback) { |
| 139 | if (mAdvertiser != null) { |
| 140 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 141 | Log.d(TAG, "stopAdvertising: "); |
| 142 | } |
| 143 | mAdvertiser.stopAdvertising(advertiseCallback); |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * Notifies the characteristic change via {@link BluetoothGattServer} |
| 149 | */ |
| 150 | protected void notifyCharacteristicChanged(BluetoothDevice device, |
| 151 | BluetoothGattCharacteristic characteristic, boolean confirm) { |
| 152 | if (mGattServer != null) { |
| 153 | mGattServer.notifyCharacteristicChanged(device, characteristic, confirm); |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | protected Context getContext() { |
| 158 | return mContext; |
| 159 | } |
| 160 | |
| 161 | /** |
| 162 | * Cleans up the BLE GATT server state. |
| 163 | */ |
| 164 | void cleanup() { |
| 165 | // Stops the advertiser and GATT server. This needs to be done to avoid leaks |
| 166 | if (mAdvertiser != null) { |
| 167 | mAdvertiser.cleanup(); |
| 168 | } |
| 169 | |
| 170 | if (mGattServer != null) { |
| 171 | mGattServer.clearServices(); |
| 172 | try { |
| 173 | for (BluetoothDevice d : mBluetoothManager.getConnectedDevices(GATT_SERVER)) { |
| 174 | mGattServer.cancelConnection(d); |
| 175 | } |
| 176 | } catch (UnsupportedOperationException e) { |
| 177 | Log.e(TAG, "Error getting connected devices", e); |
| 178 | } finally { |
| 179 | stopGattServer(); |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Close the GATT Server |
| 186 | */ |
| 187 | void stopGattServer() { |
| 188 | if (mGattServer == null) { |
| 189 | return; |
| 190 | } |
| 191 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 192 | Log.d(TAG, "stopGattServer"); |
| 193 | } |
| 194 | mGattServer.close(); |
| 195 | mGattServer = null; |
| 196 | } |
| 197 | |
| 198 | /** |
| 199 | * Triggered when a device (GATT client) connected. |
| 200 | * |
| 201 | * @param device Remote device that connected on BLE. |
| 202 | */ |
| 203 | protected void onRemoteDeviceConnected(BluetoothDevice device) { |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * Triggered when a device (GATT client) disconnected. |
| 208 | * |
| 209 | * @param device Remote device that disconnected on BLE. |
| 210 | */ |
| 211 | protected void onRemoteDeviceDisconnected(BluetoothDevice device) { |
| 212 | } |
| 213 | |
| 214 | /** |
| 215 | * Triggered when this BleManager receives a write request from a remote |
| 216 | * device. Sub-classes should implement how to handle requests. |
| 217 | * <p> |
| 218 | * |
| 219 | * @see BluetoothGattServerCallback#onCharacteristicWriteRequest(BluetoothDevice, int, |
| 220 | * BluetoothGattCharacteristic, boolean, boolean, int, byte[]) |
| 221 | */ |
| 222 | protected abstract void onCharacteristicWrite(BluetoothDevice device, int requestId, |
| 223 | BluetoothGattCharacteristic characteristic, boolean preparedWrite, boolean |
| 224 | responseNeeded, int offset, byte[] value); |
| 225 | |
| 226 | /** |
| 227 | * Triggered when this BleManager receives a read request from a remote device. |
| 228 | * <p> |
| 229 | * |
| 230 | * @see BluetoothGattServerCallback#onCharacteristicReadRequest(BluetoothDevice, int, int, |
| 231 | * BluetoothGattCharacteristic) |
| 232 | */ |
| 233 | protected abstract void onCharacteristicRead(BluetoothDevice device, |
| 234 | int requestId, int offset, BluetoothGattCharacteristic characteristic); |
| 235 | |
| 236 | private final BluetoothGattServerCallback mGattServerCallback = |
| 237 | new BluetoothGattServerCallback() { |
| 238 | @Override |
| 239 | public void onConnectionStateChange(BluetoothDevice device, int status, |
| 240 | int newState) { |
| 241 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 242 | Log.d(TAG, "BLE Connection State Change: " + newState); |
| 243 | } |
| 244 | switch (newState) { |
| 245 | case BluetoothProfile.STATE_CONNECTED: |
| 246 | onRemoteDeviceConnected(device); |
| 247 | break; |
| 248 | case BluetoothProfile.STATE_DISCONNECTED: |
| 249 | onRemoteDeviceDisconnected(device); |
| 250 | break; |
| 251 | default: |
| 252 | Log.w(TAG, |
| 253 | "Connection state not connecting or disconnecting; ignoring: " |
| 254 | + newState); |
| 255 | } |
| 256 | } |
| 257 | |
| 258 | @Override |
| 259 | public void onServiceAdded(int status, BluetoothGattService service) { |
| 260 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 261 | Log.d(TAG, |
| 262 | "Service added status: " + status + " uuid: " + service.getUuid()); |
| 263 | } |
| 264 | } |
| 265 | |
| 266 | @Override |
| 267 | public void onCharacteristicReadRequest(BluetoothDevice device, int requestId, |
| 268 | int offset, BluetoothGattCharacteristic characteristic) { |
| 269 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 270 | Log.d(TAG, "Read request for characteristic: " + characteristic.getUuid()); |
| 271 | } |
| 272 | |
| 273 | mGattServer.sendResponse(device, requestId, |
| 274 | BluetoothGatt.GATT_SUCCESS, offset, characteristic.getValue()); |
| 275 | onCharacteristicRead(device, requestId, offset, characteristic); |
| 276 | } |
| 277 | |
| 278 | @Override |
| 279 | public void onCharacteristicWriteRequest(BluetoothDevice device, int requestId, |
| 280 | BluetoothGattCharacteristic characteristic, boolean preparedWrite, |
| 281 | boolean responseNeeded, int offset, byte[] value) { |
| 282 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 283 | Log.d(TAG, "Write request for characteristic: " + characteristic.getUuid() |
| 284 | + "value: " + Utils.byteArrayToHexString(value)); |
| 285 | } |
| 286 | |
| 287 | mGattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, |
| 288 | offset, value); |
| 289 | onCharacteristicWrite(device, requestId, characteristic, |
| 290 | preparedWrite, responseNeeded, offset, value); |
| 291 | } |
| 292 | }; |
| 293 | } |