/**
   * Attempts to log a client in using the authentication server. Authentication server needs to run
   * on the same host as the file server.
   *
   * @throws IOException Error reading from socket.
   */
  private void login() throws IOException {
    // set up required variables
    DatagramSocket clientSocket = new DatagramSocket();
    InetAddress authServerIP =
        InetAddress
            .getLocalHost(); // because authentication server runs on same host as file server
    byte[] dataToSend;
    byte[] receivedData = new byte[BUFFER_SIZE];

    // get username and password
    String userName = inFromClient.readLine().trim(); // get username
    String password = inFromClient.readLine().trim(); // get password
    dataToSend = new String(userName + " " + password).getBytes();

    // send the username and password for processing by authentication server
    DatagramPacket packetToSend =
        new DatagramPacket(dataToSend, dataToSend.length, authServerIP, AUTHENTICATION_PORT);
    clientSocket.send(packetToSend);

    // receive the response from the authentication server
    DatagramPacket receivedPacket = new DatagramPacket(receivedData, receivedData.length);
    clientSocket.receive(receivedPacket);
    String receivedString = new String(receivedPacket.getData()).trim();
    receivedData = receivedString.getBytes();
    if (receivedString.equals("yes")) {
      outToClient.writeBytes(receivedString); // successful login
    } else {
      outToClient.writeBytes("no"); // unsuccessful login
    }
  }
Exemple #2
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  /** @return */
  public static String getIPv4Address() {
    String ipv4address = null;

    try {
      final List<NetworkInterface> networkinterfaces =
          Collections.list(NetworkInterface.getNetworkInterfaces());
      for (final NetworkInterface networkinterface : networkinterfaces) {
        final List<InetAddress> addresses = Collections.list(networkinterface.getInetAddresses());
        for (final InetAddress address : addresses) {
          if ((address == null) || address.isLoopbackAddress()) {
            continue;
          }
          if (address instanceof Inet4Address) {
            ipv4address = address.getHostAddress().toString();
            break;
          }
        }
      }
    } catch (Exception x) {
      DBG.m(x);
    }

    return ipv4address;
  }