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/*
* Copyright (c) 2019, 2024, Oracle and/or its affiliates. All rights reserved.
* 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
* published by the Free Software Foundation.
*
* 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.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/**
* @test
* @run testng/othervm -Djava.security.manager=allow -Dsun.net.maxDatagramSockets=32 UdpSocket
* @summary Basic test for a Socket to a UDP socket
*/
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.security.Permission;
import java.util.Arrays;
import java.util.ArrayDeque;
import java.util.Deque;
import java.net.BindException;
import org.testng.annotations.Test;
import static org.testng.Assert.*;
@Test
public class UdpSocket {
private static final int MAX_RETRIES = 3;
/**
* Test using the Socket API to send/receive datagrams
*/
public void testSendReceive() throws IOException {
final String MESSAGE = "hello";
try (DatagramChannel dc = DatagramChannel.open()) {
var loopback = InetAddress.getLoopbackAddress();
dc.bind(new InetSocketAddress(loopback, 0));
int port = ((InetSocketAddress) dc.getLocalAddress()).getPort();
try (Socket s = new Socket(loopback, port, false)) {
// send datagram with socket output stream
byte[] array1 = MESSAGE.getBytes("UTF-8");
s.getOutputStream().write(array1);
// receive the datagram
var buf = ByteBuffer.allocate(100);
SocketAddress remote = dc.receive(buf);
buf.flip();
assertTrue(buf.remaining() == MESSAGE.length(), "Unexpected size");
// echo the datagram
dc.send(buf, remote);
// receive datagram with the socket input stream
byte[] array2 = new byte[100];
int n = s.getInputStream().read(array2);
assertTrue(n == MESSAGE.length(), "Unexpected size");
assertEquals(Arrays.copyOf(array1, n), Arrays.copyOf(array2, n),
"Unexpected contents");
}
}
}
/**
* Test that the number of UDP sockets is limited when running with a
* security manager.
*/
public void testMaxSockets() throws Exception {
int limit = Integer.getInteger("sun.net.maxDatagramSockets");
// security manager grants all permissions
var securityManager = new SecurityManager() {
@Override public void checkPermission(Permission perm) { }
};
System.setSecurityManager(securityManager);
Deque<Socket> sockets = new ArrayDeque<>();
try {
// create the maximum number of sockets
for (int i=0; i<limit; i++) {
sockets.offer(newUdpSocket());
}
// try to create another socket - should fail
try {
Socket s = newUdpSocket();
s.close();
assertTrue(false);
} catch (IOException expected) { }
// close one socket
sockets.pop().close();
// try to create another socket - should succeed
Socket s = newUdpSocket();
// unreference the socket and wait for it to be closed by the cleaner
var ref = new WeakReference<>(s);
s = null;
while (ref.get() != null) {
System.gc();
Thread.sleep(100);
}
// try to create another socket - should succeed
s = newUdpSocket();
s.close();
} finally {
closeAll(sockets);
System.setSecurityManager(null);
}
}
private Socket newUdpSocket() throws IOException, InterruptedException {
BindException unexpected = null;
for (int i=0; i < MAX_RETRIES; i++) {
try {
return new Socket(InetAddress.getLoopbackAddress(), 8000, false);
} catch (BindException be) {
unexpected = be;
if (i != MAX_RETRIES - 1) {
System.out.printf("BindException caught: retry Socket creation [%s/%s]%n",
i + 1, MAX_RETRIES);
Thread.sleep(10 + 10 * i);
}
}
}
throw unexpected;
}
private void closeAll(Deque<Socket> sockets) throws IOException {
Socket s;
while ((s = sockets.poll()) != null) {
s.close();
}
}
}
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