/*
* ProActive Parallel Suite(TM):
* The Open Source library for parallel and distributed
* Workflows & Scheduling, Orchestration, Cloud Automation
* and Big Data Analysis on Enterprise Grids & Clouds.
*
* Copyright (c) 2007 - 2017 ActiveEon
* Contact: contact@activeeon.com
*
* This library is free software: you can redistribute it and/or
* modify it under the terms of the GNU Affero General Public License
* as published by the Free Software Foundation: version 3 of
* the License.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* If needed, contact us to obtain a release under GPL Version 2 or 3
* or a different license than the AGPL.
*/
package org.ow2.proactive.resourcemanager.utils;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InterfaceAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Enumeration;
import org.apache.log4j.Logger;
public class BroadcastDiscoveryClient {
public static final String BROADCAST_ENCODING = "UTF-8";
private static final Logger logger = Logger.getLogger(BroadcastDiscoveryClient.class);
private static final int URL_MAX_LENGTH = 1024;
private int port;
public BroadcastDiscoveryClient(int port) {
this.port = port;
}
public String discover(int timeoutInMs) throws IOException {
DatagramSocket broadcastSocket = null;
try {
broadcastSocket = new DatagramSocket();
broadcastSocket.setBroadcast(true);
broadcastToDefaultInterface(broadcastSocket);
broadcastToAllInterfaces(broadcastSocket);
return readBroadcastReply(broadcastSocket, timeoutInMs);
} catch (IOException e) {
logger.warn("Could not retrieve URL using broadcast discovery", e);
throw e;
} finally {
if (broadcastSocket != null) {
broadcastSocket.close();
}
}
}
private String readBroadcastReply(DatagramSocket broadcastSocket, int timeoutInMs) throws IOException {
byte[] replyBuffer = new byte[URL_MAX_LENGTH];
DatagramPacket replyPacket = new DatagramPacket(replyBuffer, replyBuffer.length);
broadcastSocket.setSoTimeout(timeoutInMs);
broadcastSocket.receive(replyPacket);
if (replyPacket.getLength() > 0) {
return new String(replyPacket.getData(), 0, replyPacket.getLength(), BROADCAST_ENCODING);
} else {
throw new IllegalStateException("Could not retrieve URL using broadcast discovery, received a malformed packet from " +
replyPacket.getAddress());
}
}
private void broadcastToDefaultInterface(DatagramSocket broadcastSocket) {
try {
DatagramPacket sendPacket = new DatagramPacket(new byte[0],
0,
InetAddress.getByName("255.255.255.255"),
port);
broadcastSocket.send(sendPacket);
} catch (Exception e) {
logger.warn("Could not broadcast to default interface", e);
}
}
private void broadcastToAllInterfaces(DatagramSocket c) {
try {
Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
while (interfaces.hasMoreElements()) {
NetworkInterface networkInterface = interfaces.nextElement();
if (isLoopBack(networkInterface)) {
continue;
}
for (InterfaceAddress interfaceAddress : networkInterface.getInterfaceAddresses()) {
InetAddress broadcast = interfaceAddress.getBroadcast();
if (broadcast == null) {
continue;
}
try {
DatagramPacket sendPacket = new DatagramPacket(new byte[0], 0, broadcast, port);
c.send(sendPacket);
} catch (Exception e) {
logger.warn("Could not broadcast to interface " + networkInterface.getName(), e);
}
}
}
} catch (SocketException e) {
logger.warn("Could not broadcast to all interfaces", e);
}
}
private boolean isLoopBack(NetworkInterface networkInterface) {
try {
return networkInterface.isLoopback() || !networkInterface.isUp();
} catch (SocketException e) {
return false;
}
}
}