实例介绍
【实例简介】
【实例截图】
【实例截图】
【核心代码】
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 | package me.tanghai.com;import java.io.FileInputStream;import java.io.FileOutputStream;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.DatagramChannel;import android.app.AlertDialog.Builder;import android.app.PendingIntent;import android.content.Intent;import android.net.VpnService;import android.os.Handler;import android.os.Message;import android.os.ParcelFileDescriptor;import android.util.Log;import android.widget.Toast;public class ToyVpnService extends VpnService implements Handler.Callback, Runnable { private static final String TAG = "ToyVpnService"; private String mServerAddress; private String mServerPort; private byte[] mSharedSecret; private PendingIntent mConfigureIntent; private Handler mHandler; private Thread mThread; private ParcelFileDescriptor mInterface; private String mParameters; @Override public int onStartCommand(Intent intent, int flags, int startId) { // The handler is only used to show messages. if (mHandler == null) { mHandler = new Handler(this); } // Stop the previous session by interrupting the thread. if (mThread != null) { mThread.interrupt(); } // Extract information from the intent. String prefix = getPackageName(); mServerAddress = intent.getStringExtra(prefix ".ADDRESS"); mServerPort = intent.getStringExtra(prefix ".PORT"); mSharedSecret = intent.getStringExtra(prefix ".SECRET").getBytes(); // Start a new session by creating a new thread. mThread = new Thread(this, "ToyVpnThread"); mThread.start(); return START_STICKY; } @Override public void onDestroy() { if (mThread != null) { mThread.interrupt(); } } @Override public boolean handleMessage(Message message) { if (message != null) { Toast.makeText(this, message.what, Toast.LENGTH_SHORT).show(); } return true; } @Override public synchronized void run() { try { Log.i(TAG, "Starting"); // If anything needs to be obtained using the network, get it now. // This greatly reduces the complexity of seamless handover, which // tries to recreate the tunnel without shutting down everything. // In this demo, all we need to know is the server address. InetSocketAddress server = new InetSocketAddress( mServerAddress, Integer.parseInt(mServerPort)); // We try to create the tunnel for several times. The better way // is to work with ConnectivityManager, such as trying only when // the network is avaiable. Here we just use a counter to keep // things simple. for (int attempt = 0; attempt < 10; attempt) { mHandler.sendEmptyMessage(R.string.connecting); // Reset the counter if we were connected. if (run(server)) { attempt = 0; } // Sleep for a while. This also checks if we got interrupted. Thread.sleep(3000); } Log.i(TAG, "Giving up"); } catch (Exception e) { Log.e(TAG, "Got " e.toString()); } finally { try { mInterface.close(); } catch (Exception e) { // ignore } mInterface = null; mParameters = null; mHandler.sendEmptyMessage(R.string.disconnected); Log.i(TAG, "Exiting"); } } private boolean run(InetSocketAddress server) throws Exception { DatagramChannel tunnel = null; boolean connected = false; try { // Create a DatagramChannel as the VPN tunnel. tunnel = DatagramChannel.open(); // Protect the tunnel before connecting to avoid loopback. if (!protect(tunnel.socket())) { throw new IllegalStateException("Cannot protect the tunnel"); } // Connect to the server. tunnel.connect(server); // For simplicity, we use the same thread for both reading and // writing. Here we put the tunnel into non-blocking mode. tunnel.configureBlocking(false); // Authenticate and configure the virtual network interface. handshake(tunnel); // Now we are connected. Set the flag and show the message. connected = true; mHandler.sendEmptyMessage(R.string.connected); // Packets to be sent are queued in this input stream. FileInputStream in = new FileInputStream(mInterface.getFileDescriptor()); // Packets received need to be written to this output stream. FileOutputStream out = new FileOutputStream(mInterface.getFileDescriptor()); // Allocate the buffer for a single packet. ByteBuffer packet = ByteBuffer.allocate(32767); // We use a timer to determine the status of the tunnel. It // works on both sides. A positive value means sending, and // any other means receiving. We start with receiving. int timer = 0; // We keep forwarding packets till something goes wrong. while (true) { // Assume that we did not make any progress in this iteration. boolean idle = true; // Read the outgoing packet from the input stream. int length = in.read(packet.array()); if (length > 0) { // Write the outgoing packet to the tunnel. packet.limit(length); tunnel.write(packet); packet.clear(); // There might be more outgoing packets. idle = false; // If we were receiving, switch to sending. if (timer < 1) { timer = 1; } } // Read the incoming packet from the tunnel. length = tunnel.read(packet); if (length > 0) { // Ignore control messages, which start with zero. if (packet.get(0) != 0) { // Write the incoming packet to the output stream. out.write(packet.array(), 0, length); } packet.clear(); // There might be more incoming packets. idle = false; // If we were sending, switch to receiving. if (timer > 0) { timer = 0; } } // If we are idle or waiting for the network, sleep for a // fraction of time to avoid busy looping. if (idle) { Thread.sleep(100); // Increase the timer. This is inaccurate but good enough, // since everything is operated in non-blocking mode. timer = (timer > 0) ? 100 : -100; // We are receiving for a long time but not sending. if (timer < -15000) { // Send empty control messages. packet.put((byte) 0).limit(1); for (int i = 0; i < 3; i) { packet.position(0); tunnel.write(packet); } packet.clear(); // Switch to sending. timer = 1; } // We are sending for a long time but not receiving. if (timer > 20000) { throw new IllegalStateException("Timed out"); } } } } catch (InterruptedException e) { throw e; } catch (Exception e) { Log.e(TAG, "Got " e.toString()); } finally { try { tunnel.close(); } catch (Exception e) { // ignore } } return connected; } private void handshake(DatagramChannel tunnel) throws Exception { // To build a secured tunnel, we should perform mutual authentication // and exchange session keys for encryption. To keep things simple in // this demo, we just send the shared secret in plaintext and wait // for the server to send the parameters. // Allocate the buffer for handshaking. ByteBuffer packet = ByteBuffer.allocate(1024); // Control messages always start with zero. packet.put((byte) 0).put(mSharedSecret).flip(); // Send the secret several times in case of packet loss. for (int i = 0; i < 3; i) { packet.position(0); tunnel.write(packet); } packet.clear(); // Wait for the parameters within a limited time. for (int i = 0; i < 50; i) { Thread.sleep(100); // Normally we should not receive random packets. int length = tunnel.read(packet); if (length > 0 && packet.get(0) == 0) { configure(new String(packet.array(), 1, length - 1).trim()); return; } } throw new IllegalStateException("Timed out"); } private void configure(String parameters) throws Exception { // If the old interface has exactly the same parameters, use it! if (mInterface != null && parameters.equals(mParameters)) { Log.i(TAG, "Using the previous interface"); return; } // Configure a builder while parsing the parameters. Builder builder = new Builder(); for (String parameter : parameters.split(" ")) { String[] fields = parameter.split(","); try { switch (fields[0].charAt(0)) { case 'm': builder.setMtu(Short.parseShort(fields[1])); break; case 'a': builder.addAddress(fields[1], Integer.parseInt(fields[2])); break; case 'r': builder.addRoute(fields[1], Integer.parseInt(fields[2])); break; case 'd': builder.addDnsServer(fields[1]); break; case 's': builder.addSearchDomain(fields[1]); break; } } catch (Exception e) { throw new IllegalArgumentException("Bad parameter: " parameter); } } // Close the old interface since the parameters have been changed. try { mInterface.close(); } catch (Exception e) { // ignore } // Create a new interface using the builder and save the parameters. mInterface = builder.setSession(mServerAddress) .setConfigureIntent(mConfigureIntent) .establish(); mParameters = parameters; Log.i(TAG, "New interface: " parameters); }} |
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