March 2009

I have recently started on a multi-platform project, Linux, Windows & Mac and decided to try and add Mac support to jnetpcap. Below is an initial patch. It has not been tested thoroughly but the unit tests and the "Classic libpcap" example work. I will be giving it a more thorough shakeout over the next several months. For now, if anyone else is interested, please have a look.

Index: Mac OS X.properties
===================================================================
--- Mac OS X.properties (revision 0)
+++ Mac OS X.properties (revision 0)
@@ -0,0 +1,51 @@
+################################################################################
+#
+#    Copyright (C) 2007 Sly Technologies, Inc.
+#
+#    This program is free software; you can redistribute it and/or
+#    modify it under the terms of the GNU General Public License
+#    as published by the Free Software Foundation; either version 2
+#    of the License, or (at your option) any later version.
+#
+#    This program 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 General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program; if not, write to the Free Software
+#    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+################################################################################
+
+# Singleton
+platform.darwin                        = true
+platform.arch                  = ${os.arch}
+platform.os.name               = ${os}
+
+# Top level 
+rpm.src.dir                    = ${src.dir}/rpm
+rpm.build.dir                  = ${build.dir}/rpm
+rpm.buildroot.dir              = ${basedir}/${rpm.build.dir}/INSTALL
+
+#
+lib.pcap.basename              = jnetpcap

I am trying to reconstruct a PcapPacket from a byte[] but I am getting the exception "java.lang.IllegalArgumentException: Invalid [offset,offset + length) range." being thrown.

Stack trace.

org.jnetpcap.nio.JMemory.peer(JMemory.java:383)
org.jnetpcap.packet.JPacket$State.peerTo(JPacket.java:274)
org.jnetpcap.packet.PcapPacket.peerStateAndData(PcapPacket.java:645)
org.jnetpcap.packet.PcapPacket.transferStateAndDataFrom(PcapPacket.java:679)
org.jnetpcap.packet.PcapPacket.(PcapPacket.java:382)
com.kindsight.qa.utils.rpcap.TestServer.main(TestServer.java:40)

Here is my sample code.

final byte[] tmp = ... initialized outside of the scope of this example
								
PcapPacket tmpP = new PcapPacket(tmp);

System.out.println("Packet : \n" + tmpP.toHexdump());

Any ideas what I'm doing wrong?

I have a pretty basic application which simply dumps out some packets from the network. I am however having a problem with my program not exiting after it breaks out of the pcap loop. Debugging the app indicates that the thread out_queue_pump is still running even though the main thread has been destroyed. What am I doing wrong?

Sample Code:

	public static void main(String[] args) throws Exception {		
		StringBuilder errbuf = new StringBuilder();
		pcap = Pcap.openLive("eth0", 64 * 1024, Pcap.MODE_NON_PROMISCUOUS,
				60 * 1000, errbuf);

		if (pcap == null) {
			System.err.printf("Error while opening device for capture: %s\n",
					errbuf.toString());
			return;
		}

		PcapPacketHandler dumpHandler = new PcapPacketHandler() {

			@Override
			public void nextPacket(PcapPacket packet, PcapDumper user) {
				System.out.println(packet.toHexdump());
			}
		};

		PcapDumper user = new PcapDumper();
		pcap.loop(10, dumpHandler, user);
		System.out.println("Trying to shutdown");
		pcap.close();		
	}

Hi!

I don't have much technical feedback yet, except that I think fragment reassembly should be part of the API somehow, maybe in PcapPacketSupport.

I have some license feedback though; it appears that examples / tutorials also are LGPL in the same way that the library is. Technically/legally this makes it problematic to use the examples as a basis for commercial code since LGPL "works" differently for integrated code and dynamically linked libraries (such as the main jNetPcap library.

Therefore I suggest that you use a free'er license for the examples, for instance Apache 2.0 (considering it is a widely used Java license). If not, I would have to ask for variance on the fragment reassembly example