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      1 /*
      2  * Copyright (C) 2017 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 android.bluetooth.BluetoothDevice;
     19 import android.bluetooth.BluetoothGatt;
     20 import android.bluetooth.BluetoothGattCharacteristic;
     21 import android.bluetooth.BluetoothGattService;
     22 import android.content.Context;
     23 import android.content.SharedPreferences;
     24 import android.os.Handler;
     25 import android.os.ParcelUuid;
     26 import android.preference.PreferenceManager;
     27 import android.util.Base64;
     28 import android.util.Log;
     29 import android.view.View;
     30 import android.widget.Button;
     31 import android.widget.TextView;
     32 import com.android.car.trust.comms.SimpleBleClient;
     33 
     34 import java.util.UUID;
     35 
     36 /**
     37  * A controller that sets up a {@link SimpleBleClient} to connect to the BLE unlock service.
     38  */
     39 public class PhoneUnlockController {
     40     private static final String TAG = "PhoneUnlockController";
     41 
     42     private String mTokenHandleKey;
     43     private String mEscrowTokenKey;
     44 
     45     // BLE characteristics associated with the enrolment/add escrow token service.
     46     private BluetoothGattCharacteristic mUnlockTokenHandle;
     47     private BluetoothGattCharacteristic mUnlockEscrowToken;
     48 
     49     private ParcelUuid mUnlockServiceUuid;
     50 
     51     private SimpleBleClient mClient;
     52     private Context mContext;
     53 
     54     private TextView mTextView;
     55     private Handler mHandler;
     56 
     57     private Button mScanButton;
     58     private Button mUnlockButton;
     59 
     60     public PhoneUnlockController(Context context) {
     61         mContext = context;
     62 
     63         mTokenHandleKey = context.getString(R.string.pref_key_token_handle);
     64         mEscrowTokenKey = context.getString(R.string.pref_key_escrow_token);
     65 
     66         mClient = new SimpleBleClient(context);
     67         mUnlockServiceUuid = new ParcelUuid(
     68                 UUID.fromString(mContext.getString(R.string.unlock_service_uuid)));
     69         mClient.addCallback(mCallback /* callback */);
     70 
     71         mHandler = new Handler(mContext.getMainLooper());
     72     }
     73 
     74     /**
     75      * Binds the views to the actions that can be performed by this controller.
     76      *
     77      * @param textView    A text view used to display results from various BLE actions
     78      * @param scanButton  Button used to start scanning for available BLE devices.
     79      * @param enrolButton Button used to send new escrow token to remote device.
     80      */
     81     public void bind(TextView textView, Button scanButton, Button enrolButton) {
     82         mTextView = textView;
     83         mScanButton = scanButton;
     84         mUnlockButton = enrolButton;
     85 
     86         mScanButton.setOnClickListener(new View.OnClickListener() {
     87             @Override
     88             public void onClick(View v) {
     89                 mClient.start(mUnlockServiceUuid);
     90             }
     91         });
     92 
     93         mUnlockButton.setEnabled(false);
     94         mUnlockButton.setAlpha(0.3f);
     95         mUnlockButton.setOnClickListener(new View.OnClickListener() {
     96             @Override
     97             public void onClick(View v) {
     98                 appendOutputText("Sending unlock token and handle to remote device");
     99                 sendUnlockRequest();
    100             }
    101         });
    102     }
    103 
    104     private void sendUnlockRequest() {
    105         // Retrieve stored token and handle and write to remote device.
    106         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
    107         long handle = prefs.getLong(mTokenHandleKey, -1);
    108         byte[] token = Base64.decode(prefs.getString(mEscrowTokenKey, null), Base64.DEFAULT);
    109 
    110         mUnlockEscrowToken.setValue(token);
    111         mUnlockTokenHandle.setValue(Utils.getBytes(handle));
    112 
    113         mClient.writeCharacteristic(mUnlockEscrowToken);
    114         mClient.writeCharacteristic(mUnlockTokenHandle);
    115     }
    116 
    117     private SimpleBleClient.ClientCallback mCallback = new SimpleBleClient.ClientCallback() {
    118         @Override
    119         public void onDeviceConnected(BluetoothDevice device) {
    120             appendOutputText("Device connected: " + device.getName()
    121                     + " addr: " + device.getAddress());
    122         }
    123 
    124         @Override
    125         public void onDeviceDisconnected() {
    126             appendOutputText("Device disconnected");
    127         }
    128 
    129         @Override
    130         public void onCharacteristicChanged(BluetoothGatt gatt,
    131                 BluetoothGattCharacteristic characteristic) {
    132             // Not expecting any characteristics changes for the unlocking client.
    133         }
    134 
    135         @Override
    136         public void onServiceDiscovered(BluetoothGattService service) {
    137             if (!service.getUuid().equals(mUnlockServiceUuid.getUuid())) {
    138                 if (Log.isLoggable(TAG, Log.DEBUG)) {
    139                     Log.d(TAG, "Service UUID: " + service.getUuid()
    140                         + " does not match Enrolment UUID " + mUnlockServiceUuid.getUuid());
    141                 }
    142                 return;
    143             }
    144 
    145             if (Log.isLoggable(TAG, Log.DEBUG)) {
    146                 Log.d(TAG, "Unlock Service # characteristics: "
    147                         + service.getCharacteristics().size());
    148             }
    149             mUnlockEscrowToken
    150                     = Utils.getCharacteristic(R.string.unlock_escrow_token_uiid, service, mContext);
    151             mUnlockTokenHandle
    152                     = Utils.getCharacteristic(R.string.unlock_handle_uiid, service, mContext);
    153             appendOutputText("Unlock BLE client successfully connected");
    154 
    155             mHandler.post(new Runnable() {
    156                 @Override
    157                 public void run() {
    158                     // Services are now set up, allow users to enrol new escrow tokens.
    159                     mUnlockButton.setEnabled(true);
    160                     mUnlockButton.setAlpha(1.0f);
    161                 }
    162             });
    163         }
    164     };
    165 
    166     private void appendOutputText(final String text) {
    167         mHandler.post(new Runnable() {
    168             @Override
    169             public void run() {
    170                 mTextView.append("\n" + text);
    171             }
    172         });
    173     }
    174 }
    175