package MV3500Cohort2018JanuaryMarch.homework3;
// package edu.nps.moves.examples; // copy example from OpenDIS distribution, modify to serve as template
import java.io.*;
import java.net.*;
import java.util.*;
import edu.nps.moves.dis.*; // OpenDIS version 4
import edu.nps.moves.disutil.DisTime;
/**
* Creates and sends ESPDUs in IEEE binary format.
*
* @author DMcG
*/
public class Sasala_OpenDisEspduSender1
{
/**
* Default constructor to silence javadoc warning
* @see <a href="https://stackoverflow.com/questions/4488716/java-default-constructor" target="_blank">StackOverflow: Java default constructor</a>
*/
public Sasala_OpenDisEspduSender1 ()
{
// default initializations
}
static final int NUMBER_TO_SEND = 5000;
/** Type of network connection */
public enum NetworkMode {
/** enumeration
* @see <a href="https://en.wikipedia.org/wiki/Unicast" target="_blank">https://en.wikipedia.org/wiki/Unicast</a> */
UNICAST,
/** enumeration
* @see <a href="https://en.wikipedia.org/wiki/Multicast" target="_blank">https://en.wikipedia.org/wiki/Multicast</a> */
MULTICAST,
/** enumeration
* @see <a href="https://en.wikipedia.org/wiki/Broadcasting_(networking)" target="_blank">https://en.wikipedia.org/wiki/Broadcasting_(networking)</a> */
BROADCAST
};
/** Default multicast group address we send on */
public static final String DEFAULT_MULTICAST_GROUP="239.1.2.3";
/** Default port we send on */
public static final int DIS_DESTINATION_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
*/
@SuppressWarnings("deprecation")
public static void main(String args[])
{
/** 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 radians = 0;
// Default settings. These are used if no system properties are set.
// If system properties are passed in, these are over ridden.
int port = DIS_DESTINATION_PORT;
NetworkMode mode = NetworkMode.BROADCAST;
InetAddress destinationIp = null; // must be initialized, even if null
try
{
destinationIp = InetAddress.getByName(DEFAULT_MULTICAST_GROUP);
}
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);
socket = new MulticastSocket(port);
// Where we send packets to, the destination IP address
if(destinationIpString != null)
{
destinationIp = InetAddress.getByName(destinationIpString);
}
// Type of transport: unicast, broadcast, or multicast
// TODO convert to String constants
if(networkModeString != null)
{
if(networkModeString.equalsIgnoreCase("unicast"))
mode = NetworkMode.UNICAST;
else if(networkModeString.equalsIgnoreCase("broadcast"))
mode = NetworkMode.BROADCAST;
else if(networkModeString.equalsIgnoreCase("multicast"))
{
mode = NetworkMode.MULTICAST;
if(!destinationIp.isMulticastAddress())
{
throw new RuntimeException("Sending to multicast address, but destination address " + destinationIp.toString() + "is not multicast");
}
socket.joinGroup(destinationIp);
}
} // end networkModeString
}
catch(IOException | RuntimeException e)
{
System.out.println("Unable to initialize networking. Exiting.");
System.out.println(e);
System.exit(-1);
}
// Initialize values in the Entity State PDU object. The exercise ID is
// a way to differentiate between different virtual worlds on one network.
// Note that some values (such as the PDU type and PDU family) are set
// automatically when you create the ESPDU.
espdu.setExerciseID((short)1);
// The EID is the unique identifier for objects in the world. This
// EID should match up with the ID for the object specified in the
// VMRL/x3d/virtual world.
EntityID entityID = espdu.getEntityID();
entityID.setSite(1); // 0 is apparently not a valid site number, per the spec
entityID.setApplication(1);
entityID.setEntity(2);
// Set the entity type. SISO has a big list of enumerations, so that by
// 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
// separate project elsehwhere in this project that implements DIS
// enumerations in C++ and Java, but to keep things simple we just use
// numbers here.
EntityType entityType = espdu.getEntityType();
entityType.setEntityKind((short)1); // Platform (vs lifeform, munition, sensor, etc.)
entityType.setCountry(225); // USA
entityType.setDomain((short)1); // Land (vs air, surface, subsurface, space)
entityType.setCategory((short)1); // Tank
entityType.setSubcategory((short)1); // M1 Abrams
entityType.setSpec((short)3); // M1A2 Abrams
Set<InetAddress> broadcastAddresses;
// Loop through sending N ESPDUs
try
{
System.out.println("Sending " + NUMBER_TO_SEND + " ESPDU packets to " + destinationIp.toString());
for(int idx = 0; idx < NUMBER_TO_SEND; idx++)
{
// DIS time is a pain in the ass. DIS time units are 2^31-1 units per
// hour, and time is set to DIS time units from the top of the hour.
// 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
// (escpecially homegrown ones) are often not able to detect rollover
// and may start discarding packets as dupes or out of order. We use
// 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
// 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
// increasing.
// Note that timestamp is used to detect duplicate and out of order packets.
// That means if you DON'T change the timestamp, many implementations will simply
// discard subsequent packets that have an identical timestamp. Also, if they
// receive a PDU with an timestamp lower than the last one they received, they
// may discard it as an earlier, out-of-order PDU. So it is a good idea to
// update the timestamp on ALL packets sent.
// An alterative approach: actually follow the standard. It's a crazy concept,
// but it might just work.
int timestamp = disTime.getDisAbsoluteTimestamp();
espdu.setTimestamp(timestamp);
// Set the position of the entity in the world. DIS uses a cartesian
// coordinate system with the origin at the center of the earth, the x
// axis out at the equator and prime meridian, y out at the equator and
// 90 deg east, and z up and out the north pole. To place an object on
// the earth's surface you also need a model for the shape of the earth
// (it's not a sphere.) All the fancy math necessary to do this is in
// the SEDRIS SRM package. There are also some one-off formulas for
// doing conversions from, for example, lat/lon/altitude to DIS coordinates.
// Here we use those one-off formulas.
radians = (radians + (Math.PI/6)) % (2*Math.PI);
Vector3Double location = espdu.getEntityLocation();
location.setX(Math.cos(radians)*1000);
location.setY(Math.sin(radians)*1000);
location.setZ(250);
// Optionally, we can do some rotation of the entity
Orientation orientation = espdu.getEntityOrientation();
orientation.setTheta((float)(radians + (Math.PI/2))%(float)(Math.PI *2));
// You can set other ESPDU values here, such as the velocity, acceleration,
// and so on.
// Marshal out the espdu object to a byte array, then send a datagram
// packet with that data in it.
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(baos);
espdu.marshal(dos);
FirePdu fire = new FirePdu();
byte[] fireArray = fire.marshal();
// The byte array here is the packet in DIS format. We put that into a
// datagram and send it.
byte[] data = baos.toByteArray();
broadcastAddresses = getBroadcastAddresses();
Iterator it = broadcastAddresses.iterator();
while(it.hasNext())
{
InetAddress broadcast = (InetAddress)it.next();
System.out.println("Sending broadcast datagram packet to " + broadcast);
DatagramPacket packet = new DatagramPacket(data, data.length, broadcast, 3000);
socket.send(packet);
// TODO experiment with these! 8)
packet = new DatagramPacket(fireArray, fireArray.length, broadcast, 3000); // alternate
socket.send(packet);
}
// Send every 1 sec. Otherwise this will be all over in a fraction of a second.
Thread.sleep(3000);
location = espdu.getEntityLocation();
System.out.println("Espdu #" + idx + " EID=[" + entityID.getSite() + "," + entityID.getApplication() + "," + entityID.getEntity() + "]");
System.out.println(" DIS coordinates location=[" + location.getX() + "," + location.getY() + "," + location.getZ() + "]");
System.out.println(" Orientation: " + orientation.getTheta());
//System.out.println(" Location (lat/lon/alt): [" + lat + ", " + lla[1] + ", " + lla[2] + "]");
}
}
catch(IOException | InterruptedException e)
{
System.out.println(e);
}
}
/**
* 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 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
* some VMs running on your host this will pick up the addresses for those
* as well--eg 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
*/
public static Set<InetAddress> getBroadcastAddresses()
{
Set<InetAddress> broadcastAddresses = new HashSet<>();
Enumeration interfaces;
try
{
interfaces = NetworkInterface.getNetworkInterfaces();
while(interfaces.hasMoreElements())
{
NetworkInterface anInterface = (NetworkInterface)interfaces.nextElement();
if(anInterface.isUp())
{
Iterator it = anInterface.getInterfaceAddresses().iterator();
while(it.hasNext())
{
InterfaceAddress anAddress = (InterfaceAddress)it.next();
if((anAddress == null || anAddress.getAddress().isLinkLocalAddress()))
continue;
//System.out.println("Getting broadcast address for " + anAddress);
InetAddress broadcastAddress = anAddress.getBroadcast();
if(broadcastAddress != null)
broadcastAddresses.add(broadcastAddress);
}
}
}
}
catch(SocketException e)
{
e.printStackTrace();
System.out.println(e);
}
return broadcastAddresses;
}
}