// $Id: PacketCaptureBase.java,v 1.5 2004/05/05 23:14:44 pcharles Exp $
/***************************************************************************
* Copyright (C) 2001, Patrick Charles and Jonas Lehmann *
* Distributed under the Mozilla Public License *
* http://www.mozilla.org/NPL/MPL-1.1.txt *
***************************************************************************/
package net.sourceforge.jpcap.capture;
import net.sourceforge.jpcap.net.Packet;
import net.sourceforge.jpcap.net.PacketFactory;
import net.sourceforge.jpcap.net.RawPacket;
import net.sourceforge.jpcap.util.Timeval;
/**
* This class contains base functionality shared by
* both the simulator and the actual packet capture system.
* <p>
* Regardless of whether 'real' packets are being captured off a network
* or 'fake' packets are being generated by the simulator,
* the packet dispatch logic is the same.
* <p>
* This class is abstract because it is useless standalone. The
* packet capture system which inherits from this class must provide a
* way of feeding data to handlePacket() where it is then dispatched to
* listeners.
*
* @author Patrick Charles and Jonas Lehmann
* @version $Revision: 1.5 $
* @lastModifiedBy $Author: pcharles $
* @lastModifiedAt $Date: 2004/05/05 23:14:44 $
*/
public abstract class PacketCaptureBase
extends PacketDispatcher implements PacketHandler
{
// internal packet handling implementation
/**
* Handle arriving packets.
* <p>
* Arriving packets are dispatched to registered packet listeners.
* If caplen is smaller than length, then the packet was truncated
* because the amount of data on the wire exceeded the snapshot length
* specified when open() was called.
* <p>
* In the simulator case, fake packets are generated and this method
* called with the fabricated data. In the case of the capture system,
* the native library libjpcap calls the method back.
*
* @param length the length of the packet off of the wire.
* @param caplen the number of bytes actually captured.
* @param seconds the seconds component of the timestamp.
* @param useconds the microseconds component of the timestamp.
* @param data the contents of the captured packet.
*/
public void handlePacket(int length, int caplen,
int seconds, int useconds, byte [] data) {
// create a raw packet and abstract packet from the raw data
Timeval tv = new Timeval(seconds, useconds);
RawPacket rp = new RawPacket(tv, data,
length > caplen ? length - caplen : 0);
Packet p = PacketFactory.dataToPacket(linkType, data, tv);
// dispatch the raw packet to registered listeners..
dispatchRawPacket(rp);
// dispatch the packet to listeners interested in packet objects..
dispatchPacket(p);
}
/**
* The link-type code for the currently open network device.
* The type is queried and set in open() and then utilized when
* packets are received by handlePacket().
*/
public int linkType;
// the following are redundant with what's stored in CaptureStatistics.
// this is temporary storage enabling the native code's statistics function
// to manipulate the results directly in this class rather than trying
// to modify fields inside an object held by this object.
// figure out how to do this more elegantly.
public int receivedCount = 0;
public int droppedCount = 0;
private String _rcsid =
"$Id: PacketCaptureBase.java,v 1.5 2004/05/05 23:14:44 pcharles Exp $";
}