Hi,
Jnetpcap is java library built using libpcap/winpcap. I provides libpcap functionalities using JNI. Sample program are available across internet who capture a certain number of packet. Here is java program who capture packet for certain predefined time interval.
/**
* Copyright (C) 2008 Sly Technologies, Inc. This library is free software; you
* can redistribute it and/or modify it under the terms of the GNU Lesser
* General Public License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version. This
* library is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details. You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package jnetpcap;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import org.jnetpcap.JBufferHandler;
import org.jnetpcap.Pcap;
import org.jnetpcap.PcapDumper;
import org.jnetpcap.PcapHeader;
import org.jnetpcap.PcapIf;
import org.jnetpcap.nio.JBuffer;
import org.jnetpcap.packet.PcapPacketHandler;
import java.util.Date;
import org.jnetpcap.packet.PcapPacket;
import org.jnetpcap.protocol.JProtocol;
/**
* This example is uses pcap library to capture live packets and dump them to console.Similar progam can be written to dump the packet to a file. Packets are captured for a certain amount of time and dumped to cosole. After the time interval expires pcap closes
*
* @author Mark Bednarczyk
* @author Sly Technologies, Inc.
*/
public class CapturePacketForCertainTimeInterval {
public static final int CAPTURE_INTERVAL = 60 * 1000; // 60 seconds in
public static void main(String[] args) {
List
alldevs = new ArrayList(); // Will be filled with
// NICs
StringBuilder errbuf = new StringBuilder(); // For any error msgs
/***************************************************************************
* First get a list of devices on this system
**************************************************************************/
int r = Pcap.findAllDevs(alldevs, errbuf);
if (r == Pcap.NOT_OK || alldevs.isEmpty()) {
System.err.printf("Can't read list of devices, error is %s", errbuf
.toString());
return;
}
PcapIf device = alldevs.get(0); // We know we have at least 1 device
/***************************************************************************
* Second we open up the selected device
**************************************************************************/
int snaplen = 64 * 1024; // Capture all packets, no truncation
int flags = Pcap.MODE_PROMISCUOUS; // capture all packets
int timeout = 10*1000; // No timeout, non-interactive traffic
Pcap pcap = Pcap.openLive(device.getName(), snaplen, flags, timeout,
errbuf);
if (pcap == null) {
System.err.printf("Error while opening device for capture: "
+ errbuf.toString());
return;
}
final long interval = System.currentTimeMillis() + CAPTURE_INTERVAL;
System.out.printf("Dump packet for "+(CAPTURE_INTERVAL/1000)+" Secs\n");
/***************************************************************************
* third we create a packet hander which receive packets and break the pcap to end capture after predefined time interval **************************************************************************/
PcapPacketHandler jpacketHandler = new PcapPacketHandler() {
public void nextPacket(PcapPacket packet, Pcap pcap) {
System.out.printf("Received packet at %s caplen=%-4d len=%-4d\n",
new Date(packet.getCaptureHeader().timestampInMillis()),
packet.getCaptureHeader().caplen(), // Length actually captured
packet.getCaptureHeader().wirelen() // Original length
);
if (System.currentTimeMillis() > interval) {
pcap.breakloop();
pcap.close();
}
}
};
/***************************************************************************
* Fourth we enter the loop. **************************************************************************/
pcap.dispatch(Pcap.LOOP_INFINITE,JProtocol.IP4_ID, jpacketHandler, pcap);
//dumper.close(); // close out the dumper and flush any unwritten packets
}
}
Note:- pcap.dispatch function may vary depending on OS implementation. I have run this code on Window XP SP3 using Netbean IDE
please feel free to contact me for any doubt. thanks
