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KeyedServerUnlock.javaAPI DocExample2220Tue Jan 25 10:45:14 GMT 2000None

KeyedServerUnlock

public class KeyedServerUnlock extends HttpServlet

Fields Summary
Constructors Summary
Methods Summary
public voiddoGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)

    PrintWriter out = res.getWriter();

    // Get the host and port
    String host = req.getParameter("host");
    String port = req.getParameter("port");

    // Convert the port to an integer
    int numericPort;
    try {
      numericPort = Integer.parseInt(port);
    }
    catch (NumberFormatException e) {
      numericPort = 80;  // default
    }

    // Generate and print the key
    // Any KeyGenerationException is caught and displayed
    try {
      long key = generateKey(host, numericPort);
      out.println(host + ":" + numericPort + " has the key " + key);
    }
    catch (KeyGenerationException e) {
      out.println("Could not generate key: " + e.getMessage());
    }
private longgenerateKey(java.lang.String host, int port)


    // The key must be a 64-bit number equal to the logical not (~) 
    // of the 32-bit IP address concatenated by the 32-bit port number.

    byte hostIP[];
    try {
      hostIP = InetAddress.getByName(host).getAddress();
    }
    catch (UnknownHostException e) {
      throw new KeyGenerationException(e.getMessage());
    }

    // Get the 32-bit IP address
    long servercode = 0;
    for (int i = 0; i < 4; i++) {
      servercode <<= 8;
      servercode |= (hostIP[i] & 255);
    }

    // Concatentate the 32-bit port number
    servercode <<= 32;
    servercode |= port;

    // The key is the logical not
    return ~servercode;