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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

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 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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 */

/**

 * @test

 * @bug 4361783

 * @key intermittent

 * @summary  Test to see if ICMP Port Unreachable on non-connected

 *           DatagramSocket causes a SocketException "socket closed"

 *           exception on Windows 2000.

 */

import java.net.BindException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

import java.net.InetSocketAddress;

public class PortUnreachable {

    DatagramSocket clientSock;

    int serverPort;

    int clientPort;

    public void serverSend() {

        try {

            InetAddress addr = InetAddress.getLocalHost();

            Thread.sleep(1000);

            // send a delayed packet which should mean a delayed icmp

            // port unreachable

            byte b[] = "A late msg".getBytes();

            DatagramPacket packet = new DatagramPacket(b, b.length, addr,

                                                       serverPort);

            clientSock.send(packet);

            DatagramSocket sock = recreateServerSocket(serverPort);

            b = "Greetings from the server".getBytes();

            packet = new DatagramPacket(b, b.length, addr, clientPort);

            sock.send(packet);

            sock.close();

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    DatagramSocket recreateServerSocket (int serverPort) throws Exception {

        DatagramSocket serverSocket = null;

        int retryCount = 0;

        long sleeptime = 0;

        System.out.println("Attempting to recreate server socket with port: " +

                serverPort);

        // it's possible that this method intermittently fails, if some other

        // process running on the machine grabs the port we want before us,

        // and doesn't release it before the 5 * 500 ms are elapsed...

        while (serverSocket == null) {

            try {

                serverSocket = new DatagramSocket(serverPort, InetAddress.getLocalHost());

            } catch (BindException bEx) {

                if (retryCount++ < 5) {

                   sleeptime += sleepAtLeast(500);

                } else {

                    System.out.println("Give up after 5 retries and " + sleeptime(sleeptime));

                    System.out.println("Has some other process grabbed port " + serverPort + "?");

                    throw bEx;

                }

            }

        }

        System.out.println("PortUnreachableTest.recreateServerSocket: returning socket == "

                + serverSocket.getLocalAddress() + ":" + serverSocket.getLocalPort()

                + " obtained at " + attempt(retryCount) + " attempt with " + sleeptime(sleeptime));

        return serverSocket;

    }

    long sleepAtLeast(long millis) throws Exception {

        long start = System.nanoTime();

        long ms = millis;

        while (ms > 0) {

            assert ms < Long.MAX_VALUE/1000_000L;

            Thread.sleep(ms);

            long elapsedms = (System.nanoTime() - start)/1000_000L;

            ms = millis - elapsedms;

        }

        return millis - ms;

    }

    String attempt(int retry) {

        switch (retry) {

            case 0: return "first";

            case 1: return "second";

            case 2: return "third";

            default: return retry + "th";

        }

    }

    String sleeptime(long millis) {

        if (millis == 0) return "no sleep";

        long sec = millis / 1000L;

        long ms =  millis % 1000L;

        String sleeptime = "";

        if (millis > 0) {

           if (sec > 0) {

               sleeptime = "" + sec + " s" +

                   (ms > 0 ? " " : "");

            }

            if (ms > 0 ) {

                sleeptime += ms + " ms";

            }

        } else sleeptime = millis + " ms"; // should not happen

        return sleeptime + " of sleep time";

    }

    PortUnreachable() throws Exception {

        clientSock = new DatagramSocket(new InetSocketAddress(InetAddress.getLocalHost(), 0));

        clientPort = clientSock.getLocalPort();

    }

    void execute () throws Exception{

        // pick a port for the server

        DatagramSocket sock2 = new DatagramSocket(new InetSocketAddress(InetAddress.getLocalHost(), 0));

        serverPort = sock2.getLocalPort();

        // send a burst of packets to the unbound port - we should get back

        // icmp port unreachable messages

        //

        InetAddress addr = InetAddress.getLocalHost();

        byte b[] = "Hello me".getBytes();

        DatagramPacket packet = new DatagramPacket(b, b.length, addr,

                                                   serverPort);

        //close just before sending

        sock2.close();

        for (int i=0; i<100; i++)

            clientSock.send(packet);

        serverSend();

        // try to receive

        b = new byte[25];

        packet = new DatagramPacket(b, b.length, addr, serverPort);

        clientSock.setSoTimeout(10000);

        clientSock.receive(packet);

        System.out.println("client received data packet " + new String(packet.getData()));

        // done

        clientSock.close();

    }

    public static void main(String[] args) throws Exception {

        PortUnreachable test = new PortUnreachable();

        test.execute();

    }

}