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package fr.dgac.ivy ;
import java.lang.Thread;
import java.net.*;
import java.io.*;
import java.util.StringTokenizer;
import gnu.regexp.*;
import java.util.Vector;
/**
* A private Class for the Ivy rendezvous
*
* @author François-Régis Colin
* @author Yannick Jestin
* @author <a href="http://www.tls.cena.fr/products/ivy/">http://www.tls.cena.fr/products/ivy/</a>
*
* right now, the rendez vous is on a UDP socket. The watcher will answer to
* each peer advertising its arrival on the bus. The intrinsics of Unix are so
* that the broadcast is done using the same socket, which is not a good
* thing.
*/
class IvyWatcher implements Runnable {
private static boolean debug = (System.getProperty("IVY_DEBUG")!=null);
private Vector domainaddrList;
private boolean watcherrunning = false;
private boolean isMulticastAddress = false;
private Thread broadcastListener ;
private Ivy bus; /* master bus controler */
private DatagramSocket broadcast; /* supervision socket */
// it can also be a MulticastSocket, which inherits from the previous
/**
* creates an Ivy watcher.
* @param bus the bus
*/
IvyWatcher(Ivy bus) throws IvyException {
this.bus = bus;
domainaddrList = new Vector();
}
/**
* the behaviour of the thread watching the UDP socket.
* this thread will stop either when the bus stops or when the
* watcherrunning will be set to false
*/
public void run() {
traceDebug("IvyWatcher waiting for Broadcast");
while( watcherrunning && bus.ivyRunning ) try {
byte buf[] = new byte[256];
DatagramPacket packet=new DatagramPacket(buf, 256);
int port;
broadcast.receive(packet);
String msg = new String(packet.getData()) ;
InetAddress remotehost = packet.getAddress();
traceDebug("BUSWATCHER Receive Broadcast from "+
remotehost.getHostName()+":"+packet.getPort());
// check if remoteaddr is in our broadcast domain list
// otherwise we ignore the broadcast
if ( !isInDomain( remotehost ) ) continue;
StringTokenizer st = new StringTokenizer(msg);
if ( !st.hasMoreTokens()) {
System.err.println("Bad format "+msg);
continue;
}
int version = Integer.parseInt( st.nextToken() );
if ( version != bus.PROCOCOLVERSION ) {
System.err.println("Ignoring bad protocol version broadcast");
continue;
}
if ( ! st.hasMoreTokens()) {
System.err.println("Bad format "+msg);
continue;
}
port = Integer.parseInt( st.nextToken() );
if ( (bus.applicationPort == port) ) continue;
traceDebug("BUSWATCHER Broadcast de "
+packet.getAddress().getHostName()
+":"+packet.getPort()+" port "+port+" version "+version);
try {
Socket socket = new Socket( remotehost, port );
bus.addClient(socket,false);
} catch ( UnknownHostException e ) {
System.err.println("Unkonwn host "+remotehost + e.getMessage());
} catch ( IOException e) {
System.err.println("can't connect to "+remotehost+" port "+
port+e.getMessage());
}
} catch ( IOException e ) {
watcherrunning=false;
traceDebug("broadcast listener crashed " + e.getMessage());
}
broadcast.close();
traceDebug("broadcast listener normal shutdown");
}
/**
* stops the thread waiting on the broadcast socket
*/
void stop() { watcherrunning=false; }
private void sendBroadcast(String data, String net) throws IvyException {
try {
// simple trick to expand to 255 (Alex Bustico)
net += ".255.255.255";
RE exp = new RE( "^(\\d+\\.\\d+\\.\\d+\\.\\d+).*");
net = exp.substitute( net , "$1" );
} catch ( REException e ){
throw new IvyException("Bad broascat addr");
}
try {
InetAddress iaddr = InetAddress.getByName(net);
domainaddrList.addElement(iaddr);
DatagramPacket packet = new DatagramPacket(
data.getBytes(),
data.length(),
iaddr,
broadcast.getLocalPort() );
broadcast.send(packet);
} catch ( UnknownHostException e ) {
throw new IvyException("Broadcast sent on unknown network "+
e.getMessage());
} catch ( IOException e ) {
throw new IvyException("Broadcast error " + e.getMessage() );
}
}
void start(String domain) throws IvyException {
String domainaddr;
// parse Domain to get port number
int port;
int sep_index = domain.lastIndexOf( ":" );
if ( sep_index == -1 ) {
port = bus.DEFAULT_PORT;
domainaddr = domain;
} else {
port = Integer.parseInt( domain.substring( sep_index +1 ));
domainaddr = domain.substring(0,sep_index);
}
// Handling of multicast address
try {
InetAddress group = InetAddress.getByName(domainaddr);
if (group.isMulticastAddress()) {
isMulticastAddress = true;
broadcast = new MulticastSocket(port ); // create the UDP socket
((MulticastSocket)broadcast).joinGroup(group);
} else {
broadcast = new MulticastSocket(port ); // create the UDP socket
}
} catch ( IOException e ) {
throw new IvyException("IvyWatcher I/O error" + e );
}
// starts a Thread listening on the socket
watcherrunning=true;
broadcastListener = new Thread(this);
broadcastListener.start();
// notifies our arrival on each domain: protocol version + port
String hello = bus.PROCOCOLVERSION + " " + bus.applicationPort + "\n";
StringTokenizer st = new StringTokenizer(domainaddr," \t:,");
while ( st.hasMoreTokens()) { sendBroadcast( hello, st.nextToken() ); }
}
private boolean isInDomain( InetAddress host ){
byte rem_addr[] = host.getAddress();
for ( int i = 0 ; i < domainaddrList.size(); i++ ) {
byte addr[] = ((InetAddress)domainaddrList.elementAt(i)).getAddress();
int j ;
for ( j = 0 ; j < 4 ; j++ )
if ( (addr[j] != -1) && (addr[j] != rem_addr[j]) ) break;
if ( j == 4 ) {
traceDebug( "host " + host + " is in domain\n" );
return true;
}
}
traceDebug( "host " + host + " Not in domain\n" );
return false;
}
private void traceDebug(String s){
if (debug) System.out.println("-->ivywatcher<-- "+s);
}
} // class IvyWatcher
/* EOF */
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