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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/* @test
 * @bug 7132924 8285515
 * @library /test/lib
 * @key intermittent
 * @summary Test DatagramChannel.disconnect when DatagramChannel is connected to an IPv4 socket
 * @run main Disconnect
 * @run main/othervm -Djava.net.preferIPv4Stack=true Disconnect
 */

import java.net.*;
import java.nio.*;
import java.nio.channels.*;
import java.io.IOException;

import jdk.test.lib.net.IPSupport;

public class Disconnect {
    public static void main(String[] args) throws IOException {
        IPSupport.throwSkippedExceptionIfNonOperational();

        // test with default protocol family
        try (DatagramChannel dc = DatagramChannel.open()) {
            InetAddress lo = InetAddress.getLoopbackAddress();
            System.out.println("Testing with default family and " + lo);
            test(dc, lo);
            test(dc, lo);
        }

        if (IPSupport.hasIPv4()) {
            // test with IPv4 only
            try (DatagramChannel dc = DatagramChannel.open(StandardProtocolFamily.INET)) {
                InetAddress lo4 = InetAddress.ofLiteral("127.0.0.1");
                System.out.println("Testing with INET family and " + lo4);
                test(dc, lo4);
                test(dc, lo4);
            }
        }

        if (IPSupport.hasIPv6()) {
            // test with IPv6 only
            try (DatagramChannel dc = DatagramChannel.open(StandardProtocolFamily.INET6)) {
                InetAddress lo6 = InetAddress.ofLiteral("::1");
                System.out.println("Testing with INET6 family and " + lo6);
                test(dc, lo6);
                test(dc, lo6);
            }
        }
    }

    static int getLocalPort(DatagramChannel ch) throws IOException {
        return ((InetSocketAddress) ch.getLocalAddress()).getPort();
    }

    /**
     * Connect DatagramChannel to a server, write a datagram and disconnect. Invoke
     * a second or subsequent time with the same DatagramChannel instance to check
     * that disconnect works as expected.
     */
    static void test(DatagramChannel dc, InetAddress lo) throws IOException {
        try (DatagramChannel server = DatagramChannel.open()) {
            server.bind(new InetSocketAddress(lo, 0));

            SocketAddress dcbound = dc.getLocalAddress();
            dc.connect(new InetSocketAddress(lo, server.socket().getLocalPort()));
            System.out.println("dc bound to " + dcbound + " and connected from " +
                    dc.getLocalAddress() + " to " + dc.getRemoteAddress());

            dc.write(ByteBuffer.wrap("hello".getBytes()));

            if (getLocalPort(dc) != getLocalPort(server)) {
                ByteBuffer bb = ByteBuffer.allocate(100);
                server.receive(bb);
            } else {
                // some systems may allow dc and server to bind to the same port.
                // when that happen the datagram may never be received
                System.out.println("Server and clients are bound to the same port: skipping receive");
            }

            dc.disconnect();

            try {
                dc.write(ByteBuffer.wrap("another message".getBytes()));
                throw new RuntimeException("write should fail, not connected");
            } catch (NotYetConnectedException expected) {
            }
        }
    }
}