I have made a jNetPcap project for which the code is below:
When I try executing the program I got this as result in the console tag:
"Can't read list of devices, error is"
and since jNetPcap depends on Libpcap C library which requires root privileges, it's obvious that's the reason why my program could not run. Could someone help me on that problem?
Note: I have tried to create .jar file in the src folder and create an .exe from this .jar file, but it throws the following errors:
Exception in thread "main" java.lang.NoClassDefFoundError: org/jnetpcap/packet/PcapPacketHandler
Caused by: java.lang.ClassNotFoundException: org.jnetpcap.packet.PcapPacketHandler
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Could not find the main class: Pcap_capture. Program will exit.
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.jnetpcap.Pcap;
import org.jnetpcap.PcapIf;
import org.jnetpcap.packet.PcapPacket;
import org.jnetpcap.packet.PcapPacketHandler;
/**
* Here is the output generated by this example :
*
* Network devices found:
* #0: \Device\NPF_{BC81C4FC-242F-4F1C-9DAD-EA9523CC992D} [Intel(R) PRO/100 VE]
* #1: \Device\NPF_{E048DA7F-D007-4EEF-909D-4238F6344971} [VMware Virtual Ethernet Adapter]
* #2: \Device\NPF_{5B62B373-3EC1-460D-8C71-54AA0BF761C7} [VMware Virtual Ethernet Adapter]
* #3: \Device\NPF_GenericDialupAdapter [Adapter for generic dialup and VPN capture]
*
* Choosing 'Intel(R) PRO/100 VE) ' on your behalf:
* Received packet at Tue Nov 03 18:52:42 EST 2009 caplen=1362 len=1362 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=82 len=82 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=145 len=145 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=62 len=62 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=164 len=164 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=62 len=62 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=54 len=54 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=1073 len=1073 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=1514 len=1514 jNetPcap rocks!
* Received packet at Tue Nov 03 18:52:45 EST 2009 caplen=279 len=279 jNetPcap rocks!
*/
public class Pcap_capture {
/**
* Main startup method
*
* @param args
* ignored
* @throws IOException
*/
public static void main(String[] args) throws IOException {
List<PcapIf> alldevs = new ArrayList<PcapIf>(); // Will be filled with NICs
StringBuilder errbuf = new StringBuilder(); // For any error msgs
boolean retval = false;
/***************************************************************************
* First get a list of devices on this system
**************************************************************************/
Process suprocess = Runtime.getRuntime().exec("su");
DataOutputStream os = new DataOutputStream(suprocess.getOutputStream());
DataInputStream is = new DataInputStream(suprocess.getInputStream());
if (null != os && null != is)
{
// Getting the id of the current user to check if this is root
os.writeBytes("id\n");
os.flush();
String currUid = is.readLine();
boolean exitSu = false;
if (null == currUid)
{
retval = false;
exitSu = false;
}
else if (true == currUid.contains("uid=0"))
{
retval = true;
exitSu = true;
}
else
{
retval = false;
exitSu = true;
}
if (exitSu)
{
os.writeBytes("exit\n");
os.flush();
}
}
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;
}
System.out.println("Network devices found:");
int i = 0;
for (PcapIf device : alldevs) {
String description =
(device.getDescription() != null) ? device.getDescription()
: "No description available";
System.out.printf("#%d: %s [%s]\n", i++, device.getName(), description);
}
PcapIf device = alldevs.get(0); // We know we have atleast 1 device
System.out
.printf("\nChoosing '%s' on your behalf:\n",
(device.getDescription() != null) ? device.getDescription()
: device.getName());
/***************************************************************************
* Second we open up the selected device
**************************************************************************/
int snaplen = 64 * 1024; // Capture all packets, no trucation
int flags = Pcap.MODE_PROMISCUOUS; // capture all packets
int timeout = 10 * 1000; // 10 seconds in millis
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;
}
/***************************************************************************
* Third we create a packet handler which will receive packets from the
* libpcap loop.
**************************************************************************/
PcapPacketHandler<String> jpacketHandler = new PcapPacketHandler<String>() {
public void nextPacket(PcapPacket packet, String user) {
System.out.printf("Received packet at %s caplen=%-4d len=%-4d %s\n",
new Date(packet.getCaptureHeader().timestampInMillis()),
packet.getCaptureHeader().caplen(), // Length actually captured
packet.getCaptureHeader().wirelen(), // Original length
user // User supplied object
);
}
};
/***************************************************************************
* Fourth we enter the loop and tell it to capture 10 packets. The loop
* method does a mapping of pcap.datalink() DLT value to JProtocol ID, which
* is needed by JScanner. The scanner scans the packet buffer and decodes
* the headers. The mapping is done automatically, although a variation on
* the loop method exists that allows the programmer to sepecify exactly
* which protocol ID to use as the data link type for this pcap interface.
**************************************************************************/
pcap.loop(10, jpacketHandler, "jNetPcap rocks!");
/***************************************************************************
* Last thing to do is close the pcap handle
**************************************************************************/
pcap.close();
}
}
I'm not sure if you want help with (1) "Can't read list of devices" error or with (2) "Exception in Thread...." error.
Error message (2) means it cannot find the file specified(specified in the error message).
Extract the "com" and "org" folders from the jnetpcap.jar file and place them in the .jar file of your program. For example if the .jar file of your program is called "test.jar", place the above folders in test.jar You can remove or put files/folders in a .jar file by using any compression program such as 7-zip.