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1 /*
2  * Copyright (C) 2011 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 
17 package com.example.android.toyvpn;
18 
19 import android.app.Notification;
20 import android.app.NotificationChannel;
21 import android.app.NotificationManager;
22 import android.app.PendingIntent;
23 import android.content.Intent;
24 import android.content.SharedPreferences;
25 import android.net.VpnService;
26 import android.os.Handler;
27 import android.os.Message;
28 import android.os.ParcelFileDescriptor;
29 import android.util.Log;
30 import android.util.Pair;
31 import android.widget.Toast;
32 
33 import java.io.IOException;
34 import java.util.Collections;
35 import java.util.Set;
36 import java.util.concurrent.atomic.AtomicInteger;
37 import java.util.concurrent.atomic.AtomicReference;
38 
39 public class ToyVpnService extends VpnService implements Handler.Callback {
40     private static final String TAG = ToyVpnService.class.getSimpleName();
41 
42     public static final String ACTION_CONNECT = "com.example.android.toyvpn.START";
43     public static final String ACTION_DISCONNECT = "com.example.android.toyvpn.STOP";
44 
45     private Handler mHandler;
46 
47     private static class Connection extends Pair<Thread, ParcelFileDescriptor> {
Connection(Thread thread, ParcelFileDescriptor pfd)48         public Connection(Thread thread, ParcelFileDescriptor pfd) {
49             super(thread, pfd);
50         }
51     }
52 
53     private final AtomicReference<Thread> mConnectingThread = new AtomicReference<>();
54     private final AtomicReference<Connection> mConnection = new AtomicReference<>();
55 
56     private AtomicInteger mNextConnectionId = new AtomicInteger(1);
57 
58     private PendingIntent mConfigureIntent;
59 
60     @Override
onCreate()61     public void onCreate() {
62         // The handler is only used to show messages.
63         if (mHandler == null) {
64             mHandler = new Handler(this);
65         }
66 
67         // Create the intent to "configure" the connection (just start ToyVpnClient).
68         mConfigureIntent = PendingIntent.getActivity(this, 0, new Intent(this, ToyVpnClient.class),
69                 PendingIntent.FLAG_UPDATE_CURRENT);
70     }
71 
72     @Override
onStartCommand(Intent intent, int flags, int startId)73     public int onStartCommand(Intent intent, int flags, int startId) {
74         if (intent != null && ACTION_DISCONNECT.equals(intent.getAction())) {
75             disconnect();
76             return START_NOT_STICKY;
77         } else {
78             connect();
79             return START_STICKY;
80         }
81     }
82 
83     @Override
onDestroy()84     public void onDestroy() {
85         disconnect();
86     }
87 
88     @Override
handleMessage(Message message)89     public boolean handleMessage(Message message) {
90         Toast.makeText(this, message.what, Toast.LENGTH_SHORT).show();
91         if (message.what != R.string.disconnected) {
92             updateForegroundNotification(message.what);
93         }
94         return true;
95     }
96 
connect()97     private void connect() {
98         // Become a foreground service. Background services can be VPN services too, but they can
99         // be killed by background check before getting a chance to receive onRevoke().
100         updateForegroundNotification(R.string.connecting);
101         mHandler.sendEmptyMessage(R.string.connecting);
102 
103         // Extract information from the shared preferences.
104         final SharedPreferences prefs = getSharedPreferences(ToyVpnClient.Prefs.NAME, MODE_PRIVATE);
105         final String server = prefs.getString(ToyVpnClient.Prefs.SERVER_ADDRESS, "");
106         final byte[] secret = prefs.getString(ToyVpnClient.Prefs.SHARED_SECRET, "").getBytes();
107         final boolean allow = prefs.getBoolean(ToyVpnClient.Prefs.ALLOW, true);
108         final Set<String> packages =
109                 prefs.getStringSet(ToyVpnClient.Prefs.PACKAGES, Collections.emptySet());
110         final int port = prefs.getInt(ToyVpnClient.Prefs.SERVER_PORT, 0);
111         final String proxyHost = prefs.getString(ToyVpnClient.Prefs.PROXY_HOSTNAME, "");
112         final int proxyPort = prefs.getInt(ToyVpnClient.Prefs.PROXY_PORT, 0);
113         startConnection(new ToyVpnConnection(
114                 this, mNextConnectionId.getAndIncrement(), server, port, secret,
115                 proxyHost, proxyPort, allow, packages));
116     }
117 
startConnection(final ToyVpnConnection connection)118     private void startConnection(final ToyVpnConnection connection) {
119         // Replace any existing connecting thread with the  new one.
120         final Thread thread = new Thread(connection, "ToyVpnThread");
121         setConnectingThread(thread);
122 
123         // Handler to mark as connected once onEstablish is called.
124         connection.setConfigureIntent(mConfigureIntent);
125         connection.setOnEstablishListener(tunInterface -> {
126             mHandler.sendEmptyMessage(R.string.connected);
127 
128             mConnectingThread.compareAndSet(thread, null);
129             setConnection(new Connection(thread, tunInterface));
130         });
131         thread.start();
132     }
133 
setConnectingThread(final Thread thread)134     private void setConnectingThread(final Thread thread) {
135         final Thread oldThread = mConnectingThread.getAndSet(thread);
136         if (oldThread != null) {
137             oldThread.interrupt();
138         }
139     }
140 
setConnection(final Connection connection)141     private void setConnection(final Connection connection) {
142         final Connection oldConnection = mConnection.getAndSet(connection);
143         if (oldConnection != null) {
144             try {
145                 oldConnection.first.interrupt();
146                 oldConnection.second.close();
147             } catch (IOException e) {
148                 Log.e(TAG, "Closing VPN interface", e);
149             }
150         }
151     }
152 
disconnect()153     private void disconnect() {
154         mHandler.sendEmptyMessage(R.string.disconnected);
155         setConnectingThread(null);
156         setConnection(null);
157         stopForeground(true);
158     }
159 
updateForegroundNotification(final int message)160     private void updateForegroundNotification(final int message) {
161         final String NOTIFICATION_CHANNEL_ID = "ToyVpn";
162         NotificationManager mNotificationManager = (NotificationManager) getSystemService(
163                 NOTIFICATION_SERVICE);
164         mNotificationManager.createNotificationChannel(new NotificationChannel(
165                 NOTIFICATION_CHANNEL_ID, NOTIFICATION_CHANNEL_ID,
166                 NotificationManager.IMPORTANCE_DEFAULT));
167         startForeground(1, new Notification.Builder(this, NOTIFICATION_CHANNEL_ID)
168                 .setSmallIcon(R.drawable.ic_vpn)
169                 .setContentText(getString(message))
170                 .setContentIntent(mConfigureIntent)
171                 .build());
172     }
173 }
174