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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * 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();
    }

}