/**
* Copies the properties of a specific <tt>DatagramPacket</tt> to another <tt>DatagramPacket</tt>.
* The property values are not cloned.
*
* @param src the <tt>DatagramPacket</tt> which is to have its properties copied to <tt>dest</tt>
* @param dest the <tt>DatagramPacket</tt> which is to have its properties set to the value of the
* respective properties of <tt>src</tt>
*/
public static void copy(DatagramPacket src, DatagramPacket dest) {
synchronized (dest) {
dest.setAddress(src.getAddress());
dest.setPort(src.getPort());
byte[] srcData = src.getData();
if (srcData == null) dest.setLength(0);
else {
byte[] destData = dest.getData();
if (destData == null) dest.setLength(0);
else {
int destOffset = dest.getOffset();
int destLength = destData.length - destOffset;
int srcLength = src.getLength();
if (destLength >= srcLength) destLength = srcLength;
else if (logger.isLoggable(Level.WARNING)) {
logger.log(Level.WARNING, "Truncating received DatagramPacket data!");
}
System.arraycopy(srcData, src.getOffset(), destData, destOffset, destLength);
dest.setLength(destLength);
}
}
}
}
/**
* Sends a datagram packet to the destination, with a TTL (time- to-live) other than the default
* for the socket. This method need only be used in instances where a particular TTL is desired;
* otherwise it is preferable to set a TTL once on the socket, and use that default TTL for all
* packets. This method does <B>not </B> alter the default TTL for the socket. Its behavior may be
* affected by {@code setInterface}.
*
* <p>If there is a security manager, this method first performs some security checks. First, if
* {@code p.getAddress().isMulticastAddress()} is true, this method calls the security manager's
* {@code checkMulticast} method with {@code p.getAddress()} and {@code ttl} as its arguments. If
* the evaluation of that expression is false, this method instead calls the security manager's
* {@code checkConnect} method with arguments {@code p.getAddress().getHostAddress()} and {@code
* p.getPort()}. Each call to a security manager method could result in a SecurityException if the
* operation is not allowed.
*
* @param p is the packet to be sent. The packet should contain the destination multicast ip
* address and the data to be sent. One does not need to be the member of the group to send
* packets to a destination multicast address.
* @param ttl optional time to live for multicast packet. default ttl is 1.
* @exception IOException is raised if an error occurs i.e error while setting ttl.
* @exception SecurityException if a security manager exists and its {@code checkMulticast} or
* {@code checkConnect} method doesn't allow the send.
* @deprecated Use the following code or its equivalent instead: ...... int ttl =
* mcastSocket.getTimeToLive(); mcastSocket.setTimeToLive(newttl); mcastSocket.send(p);
* mcastSocket.setTimeToLive(ttl); ......
* @see DatagramSocket#send
* @see DatagramSocket#receive
* @see SecurityManager#checkMulticast(java.net.InetAddress, byte)
* @see SecurityManager#checkConnect
*/
@Deprecated
public void send(DatagramPacket p, byte ttl) throws IOException {
if (isClosed()) throw new SocketException("Socket is closed");
checkAddress(p.getAddress(), "send");
synchronized (ttlLock) {
synchronized (p) {
if (connectState == ST_NOT_CONNECTED) {
// Security manager makes sure that the multicast address
// is allowed one and that the ttl used is less
// than the allowed maxttl.
SecurityManager security = System.getSecurityManager();
if (security != null) {
if (p.getAddress().isMulticastAddress()) {
security.checkMulticast(p.getAddress(), ttl);
} else {
security.checkConnect(p.getAddress().getHostAddress(), p.getPort());
}
}
} else {
// we're connected
InetAddress packetAddress = null;
packetAddress = p.getAddress();
if (packetAddress == null) {
p.setAddress(connectedAddress);
p.setPort(connectedPort);
} else if ((!packetAddress.equals(connectedAddress)) || p.getPort() != connectedPort) {
throw new SecurityException("connected address and packet address" + " differ");
}
}
byte dttl = getTTL();
try {
if (ttl != dttl) {
// set the ttl
getImpl().setTTL(ttl);
}
// call the datagram method to send
getImpl().send(p);
} finally {
// set it back to default
if (ttl != dttl) {
getImpl().setTTL(dttl);
}
}
} // synch p
} // synch ttl
} // method
/**
* {@collect.stats} {@description.open} Sends a datagram packet from this socket. The <code>
* DatagramPacket</code> includes information indicating the data to be sent, its length, the IP
* address of the remote host, and the port number on the remote host.
*
* <p>If there is a security manager, and the socket is not currently connected to a remote
* address, this method first performs some security checks. First, if <code>
* p.getAddress().isMulticastAddress()</code> is true, this method calls the security manager's
* <code>checkMulticast</code> method with <code>p.getAddress()</code> as its argument. If the
* evaluation of that expression is false, this method instead calls the security manager's <code>
* checkConnect</code> method with arguments <code>p.getAddress().getHostAddress()</code> and
* <code>p.getPort()</code>. Each call to a security manager method could result in a
* SecurityException if the operation is not allowed. {@description.close}
*
* @param p the <code>DatagramPacket</code> to be sent.
* @exception IOException if an I/O error occurs.
* @exception SecurityException if a security manager exists and its <code>checkMulticast</code>
* or <code>checkConnect</code> method doesn't allow the send.
* @exception PortUnreachableException may be thrown if the socket is connected to a currently
* unreachable destination. Note, there is no guarantee that the exception will be thrown.
* @exception java.nio.channels.IllegalBlockingModeException if this socket has an associated
* channel, and the channel is in non-blocking mode.
* @see java.net.DatagramPacket
* @see SecurityManager#checkMulticast(InetAddress)
* @see SecurityManager#checkConnect
* @revised 1.4
* @spec JSR-51
*/
public void send(DatagramPacket p) throws IOException {
InetAddress packetAddress = null;
synchronized (p) {
if (isClosed()) throw new SocketException("Socket is closed");
checkAddress(p.getAddress(), "send");
if (connectState == ST_NOT_CONNECTED) {
// check the address is ok wiht the security manager on every send.
SecurityManager security = System.getSecurityManager();
// The reason you want to synchronize on datagram packet
// is because you dont want an applet to change the address
// while you are trying to send the packet for example
// after the security check but before the send.
if (security != null) {
if (p.getAddress().isMulticastAddress()) {
security.checkMulticast(p.getAddress());
} else {
security.checkConnect(p.getAddress().getHostAddress(), p.getPort());
}
}
} else {
// we're connected
packetAddress = p.getAddress();
if (packetAddress == null) {
p.setAddress(connectedAddress);
p.setPort(connectedPort);
} else if ((!packetAddress.equals(connectedAddress)) || p.getPort() != connectedPort) {
throw new IllegalArgumentException(
"connected address " + "and packet address" + " differ");
}
}
// Check whether the socket is bound
if (!isBound()) bind(new InetSocketAddress(0));
// call the method to send
getImpl().send(p);
}
}
/**
* Set the received address and port in the packet. We do this when the Datagram socket is
* connected at the native level and the recvConnnectedDatagramImpl does not update the packet
* with address from which the packet was received
*
* @param packet the packet to be updated
*/
private void updatePacketRecvAddress(DatagramPacket packet) {
packet.setAddress(connectedAddress);
packet.setPort(connectedPort);
}
private void setSendPacketAddress(DatagramPacket sendPacket, DatagramPacket receivePacket) {
// Tell the client to send more data
sendPacket.setAddress(receivePacket.getAddress());
sendPacket.setPort(receivePacket.getPort());
}
public static void main(String args[]) throws Exception {
DatagramSocket r_clients = null, s_clients = null;
MulticastSocket servers = null, b_clients = null;
local = Integer.parseInt(args[1]);
rec = Integer.parseInt(args[0]);
System.out.println("Recieving arp on port " + rec + "...");
System.out.println("Recieving reply arp on port " + (rec + 1) + "...");
System.out.println("\nEmulating gateway on port " + local + "\nWaiting...");
try {
r_clients = new DatagramSocket(rec);
s_clients = new DatagramSocket(rec + 1);
b_clients = new MulticastSocket(local);
b_clients.joinGroup(InetAddress.getByName(group));
servers = new MulticastSocket(serv_port);
servers.joinGroup(InetAddress.getByName(group));
servers.setSoTimeout(10);
s_clients.setSoTimeout(10);
b_clients.setSoTimeout(10);
r_clients.setSoTimeout(10);
} catch (Exception e) {
System.out.println("error: " + e.toString());
System.exit(1);
}
byte arp_buf[] = new byte[28];
DatagramPacket arp_packet = new DatagramPacket(arp_buf, arp_buf.length);
while (true) {
try {
servers.receive(arp_packet);
System.out.println("\nGot arp from servers");
System.out.println("Sending arp to local computers");
arp_packet.setAddress(InetAddress.getByName(group));
arp_packet.setPort(local);
try {
b_clients.send(arp_packet, (byte) 255);
} catch (Exception e3) {
}
} catch (Exception e) {
try {
r_clients.receive(arp_packet);
System.out.println("\nGot arp from client");
System.out.println("Sending ARP");
arp_packet.setAddress(InetAddress.getByName(group));
arp_packet.setPort(serv_port);
try {
servers.send(arp_packet, (byte) 255);
} catch (Exception e3) {
}
} catch (Exception e2) {
try {
s_clients.receive(arp_packet);
System.out.println("\nGot reply arp from client");
arp_packet.setAddress(InetAddress.getByName(group));
arp_packet.setPort(2500);
try {
s_clients.send(arp_packet);
} catch (Exception e3) {
}
} catch (Exception e4) {
}
}
}
}
}
