socket.joinGroup updated to include networkInterface

4f4e06cb · Brutzman, Don · 37b02730 · 4f4e06cb
Commit 4f4e06cb authored 3 years ago by Brutzman, Don
--- a/examples/src/OpenDis4Examples/EspduSender.java
+++ b/examples/src/OpenDis4Examples/EspduSender.java
 package OpenDis4Examples;
 import java.io.*;
 import java.net.*;
 import java.util.*;
 import edu.nps.moves.dis.*;
 import edu.nps.moves.disutil.CoordinateConversions;
 import edu.nps.moves.disutil.DisTime;
 /**
 * Creates and sends ESPDUs in IEEE binary format. Adapted from OpenDIS library
 * example package edu.nps.moves.examples
 *
 * @author DMcG
 */
 public class EspduSender {
    /** Defining number of packets to send is superior to infinite loops
      * which have possible hazard of unstoppably sending packets as a zombie process */
 	public static final int NUMBER_TO_SEND = 5000;
    /** Type of network connection */
 	public enum NetworkMode {
        /** @see <a href="https://en.wikipedia.org/wiki/Unicast">https://en.wikipedia.org/wiki/Unicast</a> */
 		UNICAST,
        /** @see <a href="https://en.wikipedia.org/wiki/Multicast">https://en.wikipedia.org/wiki/Multicast</a> */
        MULTICAST,
        /** @see <a href="https://en.wikipedia.org/wiki/Broadcasting_(networking)">https://en.wikipedia.org/wiki/Broadcasting_(networking)</a> */
        BROADCAST
 	};
 	/**
 	 * Default multicast group address we send on.
 	 */
 	public static final String DEFAULT_MULTICAST_ADDRESS = "239.1.2.3";
 	/**
 	 * Default multicast port used, matches Wireshark DIS capture default
     * @see <a href="https://en.wikipedia.org/wiki/Port_(computer_networking)">https://en.wikipedia.org/wiki/Port_(computer_networking)</a>
 	 */
 	public static final int DEFAULT_MULTICAST_PORT = 3000;
 	/**
 	 * Possible system properties, passed in via -Dattr=val networkMode:
 	 * unicast, broadcast, multicast destinationIp: where to send the packet. If
 	 * in multicast mode, this can be multicast. To determine broadcast
 	 * destination IP, use an online broadcast address calculator, for example
 	 * http://www.remotemonitoringsystems.ca/broadcast.php If in multicast mode,
 	 * a join() will be done on the multicast address. port: port used for both
 	 * source and destination.
 	 *
 	 * @param args command-line arguments
 	 */
 	public static void main(String args[])
 	{
 		System.out.println("OpenDis4Examples.EspduSender started... send " + NUMBER_TO_SEND + " ESPDUs, initial index=0");
 		/**
 		 * an entity state pdu
 		 */
 		EntityStatePdu espdu = new EntityStatePdu();
 		MulticastSocket socket = null; // must be initialized, even if null
 		DisTime disTime = DisTime.getInstance(); // TODO explain
 		int alternator = -1;
 		// ICBM coordinates for my office
 		double lat = 36.595517;
 		double lon = -121.877000;
 		// Default settings. These are used if no system properties are set. 
 		// If system properties are passed in, these are over ridden.
 		int port = DEFAULT_MULTICAST_PORT;
 		NetworkMode mode = NetworkMode.BROADCAST;
 		InetAddress destinationIp = null; // must be initialized, even if null
 		try {
 			destinationIp = InetAddress.getByName(DEFAULT_MULTICAST_ADDRESS);
 		} catch (UnknownHostException e) {
 			System.out.println(e + " Cannot create multicast address");
 			System.exit(0);
 		}
 		// All system properties, passed in on the command line via -Dattribute=value
 		Properties systemProperties = System.getProperties();
 		// IP address we send to
 		String destinationIpString = systemProperties.getProperty("destinationIp");
 		// Port we send to, and local port we open the socket on
 		String portString = systemProperties.getProperty("port");
 		// Network mode: unicast, multicast, broadcast
 		String networkModeString = systemProperties.getProperty("networkMode"); // unicast or multicast or broadcast
 		// Set up a socket to send information
 		try {
 			// Port we send to
 			if (portString != null) 
 			{
-				port = Integer.parseInt(portString);
+			    System.out.println("Using systemProperties port=" + portString);
-			}
+				port = Integer.parseInt(portString);
+			}
-			socket = new MulticastSocket(port);
+			socket = new MulticastSocket(port);
-			// Where we send packets to, the destination IP address
-			if (destinationIpString != null) 
+			// Where we send packets to, the destination IP address
-			{
+			if (destinationIpString != null) 
-				destinationIp = InetAddress.getByName(destinationIpString);
+			{
-			}
+				destinationIp = InetAddress.getByName(destinationIpString);
+			}
-			// Type of transport: unicast, broadcast, or multicast
-			// TODO convert to String constants
+			// Type of transport: unicast, broadcast, or multicast
-			if (networkModeString != null) {
+			// TODO convert to String constants
-				if (networkModeString.equalsIgnoreCase("unicast")) 
+			if (networkModeString != null) {
-				{
+				if (networkModeString.equalsIgnoreCase("unicast")) 
-					mode = NetworkMode.UNICAST;
+				{
-				} 
+					mode = NetworkMode.UNICAST;
-				else if (networkModeString.equalsIgnoreCase("broadcast")) {
+				} 
-					mode = NetworkMode.BROADCAST;
+				else if (networkModeString.equalsIgnoreCase("broadcast")) {
-				} 
+					mode = NetworkMode.BROADCAST;
-				else if (networkModeString.equalsIgnoreCase("multicast")) {
+				} 
-					mode = NetworkMode.MULTICAST;
+				else if (networkModeString.equalsIgnoreCase("multicast")) {
-					if (!destinationIp.isMulticastAddress())
+					mode = NetworkMode.MULTICAST;
-					{
+					if (!destinationIp.isMulticastAddress())
-						throw new RuntimeException("Sending to multicast address, but destination address " + destinationIp.toString() + "is not multicast");
+					{
-					}
+						throw new RuntimeException("Sending to multicast address, but destination address " + destinationIp.toString() + "is not multicast");
-					socket.joinGroup(destinationIp);
+					}
-				}
+//					socket.joinGroup(destinationIp); // deprecated, TODO select correct NetworkInterface
-			} // end networkModeString
+                    // =======================================================================
-		}
+                    // updated approach using NetworkInterface
-		catch (IOException | RuntimeException e)
+                    NetworkInterface networkInterface = NetworkInterface.getByInetAddress(destinationIp);
-		{
+                    if (networkInterface != null)
-			System.out.println("Unable to initialize networking. Exiting.");
+                        System.out.println("networkInterface=" + networkInterface.getDisplayName()); // typically null if loopback
-			System.out.println(e);
+                    SocketAddress localMulticastSocketAddress = new InetSocketAddress(destinationIp, DEFAULT_MULTICAST_PORT);
-			System.exit(-1);
+                    MulticastSocket multicastSocket = new MulticastSocket(DEFAULT_MULTICAST_PORT);
-		}
+                    multicastSocket.joinGroup(localMulticastSocketAddress, networkInterface);
+                    // =======================================================================
-		// Initialize values in the Entity State PDU object. The exercise ID is 
+				}
-		// a way to differentiate between different virtual worlds on one network.
+			} // end networkModeString
-		// Note that some values (such as the PDU type and PDU family) are set
+		}
-		// automatically when you create the ESPDU.
+		catch (IOException | RuntimeException e)
-		espdu.setExerciseID((short) 1);
+		{
+			System.out.println("Unable to initialize networking. Exiting.");
-		// The EID is the unique identifier for objects in the world. This 
+			System.out.println(e);
-		// EID should match up with the ID for the object specified in the 
+			System.exit(-1);
-		// VMRL/x3d/virtual world.
+		}
-		EntityID entityID = espdu.getEntityID();
-		entityID.setSite(1);  // 0 is apparently not a valid site number, per the spec
+		// Initialize values in the Entity State PDU object. The exercise ID is 
-		entityID.setApplication(1);
+		// a way to differentiate between different virtual worlds on one network.
-		entityID.setEntity(2);
+		// Note that some values (such as the PDU type and PDU family) are set
+		// automatically when you create the ESPDU.
-		// Set the entity type. SISO has a big list of enumerations, so that by
+		espdu.setExerciseID((short) 1);
-		// specifying various numbers we can say this is an M1A2 American tank,
-		// the USS Enterprise, and so on. We'll make this a tank. There is a 
+		// The EID is the unique identifier for objects in the world. This 
-		// separate project elsehwhere in this project that implements DIS 
+		// EID should match up with the ID for the object specified in the 
-		// enumerations in C++ and Java, but to keep things simple we just use
+		// VMRL/x3d/virtual world.
-		// numbers here.
+		EntityID entityID = espdu.getEntityID();
-		EntityType entityType = espdu.getEntityType();
+		entityID.setSite(1);  // 0 is apparently not a valid site number, per the spec
-		entityType.setEntityKind((short) 1);      // Platform (vs lifeform, munition, sensor, etc.)
+		entityID.setApplication(1);
-		entityType.setCountry(225);              // USA
+		entityID.setEntity(2);
-		entityType.setDomain((short) 1);          // Land (vs air, surface, subsurface, space)
-		entityType.setCategory((short) 1);        // Tank
+		// Set the entity type. SISO has a big list of enumerations, so that by
-		entityType.setSubcategory((short) 1);     // M1 Abrams
+		// specifying various numbers we can say this is an M1A2 American tank,
-		entityType.setSpec((short) 3);            // M1A2 Abrams
+		// the USS Enterprise, and so on. We'll make this a tank. There is a 
+		// separate project elsehwhere in this project that implements DIS 
-		Set<InetAddress> broadcastAddresses;
+		// enumerations in C++ and Java, but to keep things simple we just use
-		// Loop through sending N ESPDUs
+		// numbers here.
-		try
+		EntityType entityType = espdu.getEntityType();
-		{
+		entityType.setEntityKind((short) 1);      // Platform (vs lifeform, munition, sensor, etc.)
-			System.out.println("Sending " + NUMBER_TO_SEND + " ESPDU packets to " + destinationIp.toString());
+		entityType.setCountry(225);              // USA
+		entityType.setDomain((short) 1);          // Land (vs air, surface, subsurface, space)
-			for (int index = 0; index < NUMBER_TO_SEND; index++) {
+		entityType.setCategory((short) 1);        // Tank
-				// DIS time is a pain in the uh, neck. DIS time units are 2^31-1 units per
+		entityType.setSubcategory((short) 1);     // M1 Abrams
-				// hour, and time is set to DIS time units from the top of the hour. 
+		entityType.setSpec((short) 3);            // M1A2 Abrams
-				// This means that if you start sending just before the top of the hour
-				// the time units can roll over to zero as you are sending. The receivers
+		Set<InetAddress> broadcastAddresses;
-				// (escpecially homegrown ones) are often not able to detect rollover
+		// Loop through sending N ESPDUs
-				// and may start discarding packets as dupes or out of order. We use
+		try
-				// an NPS timestamp here, hundredths of a second since the start of the
+		{
-				// year. The DIS standard for time is often ignored in the wild; I've seen
+			System.out.println("Sending " + NUMBER_TO_SEND + " ESPDU packets to " + destinationIp.toString());
-				// people use Unix time (seconds since 1970) and more. Or you can
-				// just stuff idx into the timestamp field to get something that is monotonically
+			for (int index = 0; index < NUMBER_TO_SEND; index++) {
-				// increasing.
+				// DIS time is a pain in the uh, neck. DIS time units are 2^31-1 units per
+				// hour, and time is set to DIS time units from the top of the hour. 
-				// Note that timestamp is used to detect duplicate and out of order packets. 
+				// This means that if you start sending just before the top of the hour
-				// That means if you DON'T change the timestamp, many implementations will simply
+				// the time units can roll over to zero as you are sending. The receivers
-				// discard subsequent packets that have an identical timestamp. Also, if they
+				// (escpecially homegrown ones) are often not able to detect rollover
-				// receive a PDU with an timestamp lower than the last one they received, they
+				// and may start discarding packets as dupes or out of order. We use
-				// may discard it as an earlier, out-of-order PDU. So it is a good idea to
+				// an NPS timestamp here, hundredths of a second since the start of the
-				// update the timestamp on ALL packets sent.
+				// year. The DIS standard for time is often ignored in the wild; I've seen
-				// An alterative approach: actually follow the standard. It's a crazy concept,
+				// people use Unix time (seconds since 1970) and more. Or you can
-				// but it might just work.
+				// just stuff idx into the timestamp field to get something that is monotonically
-				int timestamp = disTime.getDisAbsoluteTimestamp();
+				// increasing.
-				espdu.setTimestamp(timestamp);
+				// Note that timestamp is used to detect duplicate and out of order packets. 
-				// Set the position of the entity in the world. DIS uses a cartesian 
+				// That means if you DON'T change the timestamp, many implementations will simply
-				// coordinate system with the origin at the center of the earth, the x
+				// discard subsequent packets that have an identical timestamp. Also, if they
-				// axis out at the equator and prime meridian, y out at the equator and
+				// receive a PDU with an timestamp lower than the last one they received, they
-				// 90 deg east, and z up and out the north pole. To place an object on
+				// may discard it as an earlier, out-of-order PDU. So it is a good idea to
-				// the earth's surface you also need a model for the shape of the earth
+				// update the timestamp on ALL packets sent.
-				// (it's not a sphere.) All the fancy math necessary to do this is in
+				// An alterative approach: actually follow the standard. It's a crazy concept,
-				// the SEDRIS SRM package. There are also some one-off formulas for 
+				// but it might just work.
-				// doing conversions from, for example, lat/lon/altitude to DIS coordinates.
+				int timestamp = disTime.getDisAbsoluteTimestamp();
-				// Here we use those one-off formulas.
+				espdu.setTimestamp(timestamp);
-				// Modify the position of the object. This will send the object a little
-				// due east by adding some to the longitude every iteration. Since we
+				// Set the position of the entity in the world. DIS uses a cartesian 
-				// are on the Pacific coast, this sends the object east. Assume we are
+				// coordinate system with the origin at the center of the earth, the x
-				// at zero altitude. In other worlds you'd use DTED to determine the
+				// axis out at the equator and prime meridian, y out at the equator and
-				// local ground altitude at that lat/lon, or you'd just use ground clamping.
+				// 90 deg east, and z up and out the north pole. To place an object on
-				// The x and y values will change, but the z value should not.
+				// the earth's surface you also need a model for the shape of the earth
-				//lon = lon + (double)((double)idx / 100000.0);
+				// (it's not a sphere.) All the fancy math necessary to do this is in
-				//System.out.println("lla=" + lat + "," + lon + ", 0.0");
+				// the SEDRIS SRM package. There are also some one-off formulas for 
-				double direction = Math.pow((double) (-1.0), (double) (index));
+				// doing conversions from, for example, lat/lon/altitude to DIS coordinates.
-				lon = lon + (direction * 0.00006);
+				// Here we use those one-off formulas.
-				System.out.println(lon);
+				// Modify the position of the object. This will send the object a little
+				// due east by adding some to the longitude every iteration. Since we
-				double disCoordinates[] = CoordinateConversions.getXYZfromLatLonDegrees(lat, lon, 1.0);
+				// are on the Pacific coast, this sends the object east. Assume we are
-				Vector3Double location = espdu.getEntityLocation();
+				// at zero altitude. In other worlds you'd use DTED to determine the
-				location.setX(disCoordinates[0]);
+				// local ground altitude at that lat/lon, or you'd just use ground clamping.
-				location.setY(disCoordinates[1]);
+				// The x and y values will change, but the z value should not.
-				location.setZ(disCoordinates[2]);
+				//lon = lon + (double)((double)idx / 100000.0);
-				System.out.println("lat, lon:" + lat + ", " + lon);
+				//System.out.println("lla=" + lat + "," + lon + ", 0.0");
-				System.out.println("DIS coord:" + disCoordinates[0] + ", " + disCoordinates[1] + ", " + disCoordinates[2]);
+				double direction = Math.pow((double) (-1.0), (double) (index));
+				lon = lon + (direction * 0.00006);
-				// Optionally, we can do some rotation of the entity
+				System.out.println(lon);
-				/*
-            Orientation orientation = espdu.getEntityOrientation();
+				double disCoordinates[] = CoordinateConversions.getXYZfromLatLonDegrees(lat, lon, 1.0);
-            float psi = orientation.getPsi();
+				Vector3Double location = espdu.getEntityLocation();
-            psi = psi + idx;
+				location.setX(disCoordinates[0]);
-            orientation.setPsi(psi);
+				location.setY(disCoordinates[1]);
-            orientation.setTheta((float)(orientation.getTheta() + idx /2.0));
+				location.setZ(disCoordinates[2]);
-				 */
+				System.out.println("lat, lon:" + lat + ", " + lon);
-				// You can set other ESPDU values here, such as the velocity, acceleration,
+				System.out.println("DIS coord:" + disCoordinates[0] + ", " + disCoordinates[1] + ", " + disCoordinates[2]);
-				// and so on.
-				// Marshal out the espdu object to a byte array, then send a datagram
+				// Optionally, we can do some rotation of the entity
-				// packet with that data in it.
+				/*
-				ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            Orientation orientation = espdu.getEntityOrientation();
-				DataOutputStream dos = new DataOutputStream(baos);
+            float psi = orientation.getPsi();
-				espdu.marshal(dos);
+            psi = psi + idx;
+            orientation.setPsi(psi);
-				FirePdu fire = new FirePdu();
+            orientation.setTheta((float)(orientation.getTheta() + idx /2.0));
-				byte[] fireArray = fire.marshal();
+				 */
+				// You can set other ESPDU values here, such as the velocity, acceleration,
-				// The byte array here is the packet in DIS format. We put that into a 
+				// and so on.
-				// datagram and send it.
+				// Marshal out the espdu object to a byte array, then send a datagram
-				byte[] data = baos.toByteArray();
+				// packet with that data in it.
+				ByteArrayOutputStream baos = new ByteArrayOutputStream();
-				broadcastAddresses = getBroadcastAddresses();
+				DataOutputStream dos = new DataOutputStream(baos);
-				Iterator iterator = broadcastAddresses.iterator();
+				espdu.marshal(dos);
-				while (iterator.hasNext())
-				{
+				FirePdu fire = new FirePdu();
-					InetAddress broadcast = (InetAddress) iterator.next();
+				byte[] fireArray = fire.marshal();
-					System.out.println("Sending broadcast datagram packet to " + broadcast);
-					DatagramPacket packet = new DatagramPacket(data, data.length, broadcast, port);
+				// The byte array here is the packet in DIS format. We put that into a 
-					socket.send(packet);
+				// datagram and send it.
-					// TODO experiment with these!  8)
+				byte[] data = baos.toByteArray();
-					packet = new DatagramPacket(fireArray, fireArray.length, broadcast, port); // alternate
-					socket.send(packet);
+				broadcastAddresses = getBroadcastAddresses();
-				}
+				Iterator iterator = broadcastAddresses.iterator();
+				while (iterator.hasNext())
-				// Send every 1 sec. Otherwise all this will be all over in a fraction of a second.
+				{
-				Thread.sleep(1000); // msec
+					InetAddress broadcast = (InetAddress) iterator.next();
+					System.out.println("Sending broadcast datagram packet to " + broadcast);
-				location = espdu.getEntityLocation();
+					DatagramPacket packet = new DatagramPacket(data, data.length, broadcast, port);
+					socket.send(packet);
-				System.out.println("Espdu #" + index + " EID=[" + entityID.getSite() + "," + entityID.getApplication() + "," + entityID.getEntity() + "]");
+					// TODO experiment with these!  8)
-				System.out.println(" DIS coordinates location=[" + location.getX() + "," + location.getY() + "," + location.getZ() + "]");
+					packet = new DatagramPacket(fireArray, fireArray.length, broadcast, port); // alternate
-				double c[] = {location.getX(), location.getY(), location.getZ()};
+					socket.send(packet);
-				double lla[] = CoordinateConversions.xyzToLatLonDegrees(c);
+				}
-// debug:		System.out.println(" Location (lat/lon/alt): [" + lla[0] + ", " + lla[1] + ", " + lla[2] + "]");
-			}
+				// Send every 1 sec. Otherwise all this will be all over in a fraction of a second.
-		}
+				Thread.sleep(1000); // msec
-		catch (IOException | InterruptedException e)
-		{
+				location = espdu.getEntityLocation();
-            System.out.println("Problem with OpenDis4Examples.EspduSender, see exception trace:");
-			System.out.println(e);
+				System.out.println("Espdu #" + index + " EID=[" + entityID.getSite() + "," + entityID.getApplication() + "," + entityID.getEntity() + "]");
-		}
+				System.out.println(" DIS coordinates location=[" + location.getX() + "," + location.getY() + "," + location.getZ() + "]");
-	}
+				double c[] = {location.getX(), location.getY(), location.getZ()};
+				double lla[] = CoordinateConversions.xyzToLatLonDegrees(c);
-	/**
+// debug:		System.out.println(" Location (lat/lon/alt): [" + lla[0] + ", " + lla[1] + ", " + lla[2] + "]");
-	 * A number of sites get all snippy about using 255.255.255.255 for a
+			}
-	 * broadcast address; it trips their security software and they kick you off
+		}
-	 * their network. (Comcast, NPS.) This determines the broadcast address for
+		catch (IOException | InterruptedException e)
-	 * all connected interfaces, based on the IP and subnet mask. If you have a
+		{
-	 * dual-homed host it will return a broadcast address for both. If you have
+            System.out.println("Problem with OpenDis4Examples.EspduSender, see exception trace:");
-	 * some VMs running on your host this will pick up the addresses for those
+			System.out.println(e);
-	 * as well--e.g. running VMWare on your laptop with a local IP this will also
+		}
-	 * pick up a 192.168 address assigned to the VM by the host OS.
+	}
-	 *
-	 * @return set of all broadcast addresses
+	/**
-	 */
+	 * A number of sites get all snippy about using 255.255.255.255 for a
-	public static Set<InetAddress> getBroadcastAddresses()
+	 * broadcast address; it trips their security software and they kick you off
-	{
+	 * their network. (Comcast, NPS.) This determines the broadcast address for
-		Set<InetAddress> broadcastAddresses = new HashSet<>();
+	 * all connected interfaces, based on the IP and subnet mask. If you have a
-		Enumeration interfaces;
+	 * dual-homed host it will return a broadcast address for both. If you have
+	 * some VMs running on your host this will pick up the addresses for those
-		try {
+	 * as well--e.g. running VMWare on your laptop with a local IP this will also
-			interfaces = NetworkInterface.getNetworkInterfaces();
+	 * pick up a 192.168 address assigned to the VM by the host OS.
+	 *
-			while (interfaces.hasMoreElements())
+	 * @return set of all broadcast addresses
-			{
+	 */
-				NetworkInterface anInterface = (NetworkInterface) interfaces.nextElement();
+	public static Set<InetAddress> getBroadcastAddresses()
+	{
-				if (anInterface.isUp())
+		Set<InetAddress> broadcastAddresses = new HashSet<>();
-				{
+		Enumeration interfaces;
-					Iterator iterator = anInterface.getInterfaceAddresses().iterator();
-					while (iterator.hasNext())
+		try {
-					{
+			interfaces = NetworkInterface.getNetworkInterfaces();
-						InterfaceAddress anAddress = (InterfaceAddress) iterator.next();
-						if ((anAddress == null || anAddress.getAddress().isLinkLocalAddress()))
+			while (interfaces.hasMoreElements())
-						{
+			{
-							continue;
+				NetworkInterface anInterface = (NetworkInterface) interfaces.nextElement();
-						}
+				if (anInterface.isUp())
-						//System.out.println("Getting broadcast address for " + anAddress);
+				{
-						InetAddress broadcastAddress = anAddress.getBroadcast();
+					Iterator iterator = anInterface.getInterfaceAddresses().iterator();
-						if (broadcastAddress != null)
+					while (iterator.hasNext())
-						{
+					{
-							broadcastAddresses.add(broadcastAddress);
+						InterfaceAddress anAddress = (InterfaceAddress) iterator.next();
-						}
+						if ((anAddress == null || anAddress.getAddress().isLinkLocalAddress()))
-					}
+						{
-				}
+							continue;
-			}
+						}
-		}
-		catch (SocketException e) 
+						//System.out.println("Getting broadcast address for " + anAddress);
-		{
+						InetAddress broadcastAddress = anAddress.getBroadcast();
-            System.out.println("Problem with OpenDis4Examples.EspduSender.getBroadcastAddresses(), see exception trace:");
+						if (broadcastAddress != null)
-			System.out.println(e);
+						{
-		}
+							broadcastAddresses.add(broadcastAddress);
-		return broadcastAddresses;
+						}
-	}
+					}
-}
+				}
+			}
+		}
+		catch (SocketException e) 
+		{
+            System.out.println("Problem with OpenDis4Examples.EspduSender.getBroadcastAddresses(), see exception trace:");
+			System.out.println(e);
+		}
+		return broadcastAddresses;
+	}
+}