net.sourceforge.jpcap.capture
Class PacketCapture

java.lang.Object
  |
  +--net.sourceforge.jpcap.capture.PacketDispatcher
        |
        +--net.sourceforge.jpcap.capture.PacketCaptureBase
              |
              +--net.sourceforge.jpcap.capture.PacketCapture
All Implemented Interfaces:
PacketCaptureCapable, PacketDispatchCapable, net.sourceforge.jpcap.capture.PacketHandler

public class PacketCapture
extends PacketCaptureBase
implements PacketCaptureCapable

This class is the core of packet capture in jpcap. It provides a high-level interface for capturing network packets by encapsulating libpcap.

If you want to capture network packets, implement PacketListener and register with an instance of this class. When packets arrive, the object will call you back via packetArrived().

Examples can be found in net.sourceforge.jpcap.tutorial.

For more documentation on this class's methods, see PacketCaptureCapable; Javadoc is 'inherited' from this interface.


Field Summary
protected static java.lang.String LIB_PCAP_WRAPPER
          Name of the java-enabled wrapper around libpcap.
 
Fields inherited from class net.sourceforge.jpcap.capture.PacketCaptureBase
droppedCount, linkType, receivedCount
 
Fields inherited from interface net.sourceforge.jpcap.capture.PacketCaptureCapable
DEFAULT_SNAPLEN, DEFAULT_TIMEOUT
 
Constructor Summary
PacketCapture()
           
 
Method Summary
 void capture(int count)
          Capture packets.
 void close()
          Close the capture device.
 java.lang.String findDevice()
          Detect a network device suitable for packet capture.
 int getLinkLayerType()
          Fetch the link layer type for the specified device.
 int getNetmask(java.lang.String device)
          Fetch the network mask for the specified device.
 int getNetwork(java.lang.String device)
          Fetch the network number for the specified device.
 int getSnapshotLength()
          Get the snapshot length given that network device is open.
 CaptureStatistics getStatistics()
          Fetch statistics on captured packets.
static java.lang.String[] lookupDevices()
          Get Interface List
 void open(java.lang.String device, boolean promiscuous)
          Open a network device for data capture.
 void open(java.lang.String device, int snaplen, boolean promiscuous, int timeout)
          Open a network device for data capture.
 void openOffline(java.lang.String fileName)
          Open a tcpdump-formatted savefile.
 void setFilter(java.lang.String filterExpression, boolean optimize)
          Create, compile and activate a filter from a filter expression.
 
Methods inherited from class net.sourceforge.jpcap.capture.PacketCaptureBase
handlePacket
 
Methods inherited from class net.sourceforge.jpcap.capture.PacketDispatcher
addPacketListener, addRawPacketListener, dispatchPacket, dispatchRawPacket, removePacketListener, removeRawPacketListener
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface net.sourceforge.jpcap.capture.PacketCaptureCapable
addPacketListener, addRawPacketListener, removePacketListener, removeRawPacketListener
 

Field Detail

LIB_PCAP_WRAPPER

protected static java.lang.String LIB_PCAP_WRAPPER
Name of the java-enabled wrapper around libpcap.
Constructor Detail

PacketCapture

public PacketCapture()
Method Detail

open

public void open(java.lang.String device,
                 boolean promiscuous)
          throws CaptureDeviceOpenException
Description copied from interface: PacketCaptureCapable
Open a network device for data capture. Throws an exception if the device name specified is invalid. Uses default values for the capture timeout and snaplen.
Specified by:
open in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Parameters:
device - the name of the network device. Examples of valid network devices on linux are 'eth0' and 'ppp0'.
promiscuous - whether or not the device should be opened in promiscuous mode.
Returns:
a string describing the network device. if no device can be found, null is returned.

open

public void open(java.lang.String device,
                 int snaplen,
                 boolean promiscuous,
                 int timeout)
          throws CaptureDeviceOpenException
Description copied from interface: PacketCaptureCapable
Open a network device for data capture.
Specified by:
open in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Parameters:
device - the name of the network device. Examples of valid network devices on linux are 'eth0' and 'ppp0'.
snaplen - the 'snapshot' length. Defines the maximum number of bytes to save from each captured packet.
promiscuous - whether or not the device should be opened in promiscuous mode.
timeout - the packet capture timeout in milliseconds.
Returns:
a string describing the network device. if no device can be found, null is returned.

openOffline

public void openOffline(java.lang.String fileName)
                 throws CaptureFileOpenException
Description copied from interface: PacketCaptureCapable
Open a tcpdump-formatted savefile.
Specified by:
openOffline in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Parameters:
fileName - the name of the savefile.

setFilter

public void setFilter(java.lang.String filterExpression,
                      boolean optimize)
               throws InvalidFilterException
Description copied from interface: PacketCaptureCapable
Create, compile and activate a filter from a filter expression.
Specified by:
setFilter in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Parameters:
filterExpression - the filter expression. For example, the expression "host techno" would filter only packets sent or arriving at the host named techno.

capture

public void capture(int count)
             throws CapturePacketException
Description copied from interface: PacketCaptureCapable
Capture packets.
Specified by:
capture in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Parameters:
count - the number of packets to capture. If count is negative, capture will block forever, unless an exception is thrown.

getStatistics

public CaptureStatistics getStatistics()
Description copied from interface: PacketCaptureCapable
Fetch statistics on captured packets. This method should not be called unless capture() was previously called.
Specified by:
getStatistics in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Returns:
packet capture statistics.

close

public void close()
Description copied from interface: PacketCaptureCapable
Close the capture device.
Specified by:
close in interface PacketCaptureCapable

lookupDevices

public static java.lang.String[] lookupDevices()
                                        throws CaptureDeviceLookupException
Get Interface List
Returns:
Network device interface names.

findDevice

public java.lang.String findDevice()
                            throws CaptureDeviceNotFoundException
Description copied from interface: PacketCaptureCapable
Detect a network device suitable for packet capture.
Specified by:
findDevice in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Returns:
a string describing the network device. if no device can be found, null is returned.

getNetwork

public int getNetwork(java.lang.String device)
               throws CaptureConfigurationException
Description copied from interface: PacketCaptureCapable
Fetch the network number for the specified device.
Specified by:
getNetwork in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Parameters:
device - the name of the network device.
Returns:
the network address

getNetmask

public int getNetmask(java.lang.String device)
               throws CaptureConfigurationException
Description copied from interface: PacketCaptureCapable
Fetch the network mask for the specified device.
Specified by:
getNetmask in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Parameters:
device - the name of the network device.
Returns:
the netmask address

getLinkLayerType

public int getLinkLayerType()
                     throws CaptureConfigurationException
Description copied from interface: PacketCaptureCapable
Fetch the link layer type for the specified device.
Specified by:
getLinkLayerType in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Returns:
the link layer type code.

getSnapshotLength

public int getSnapshotLength()
Description copied from interface: PacketCaptureCapable
Get the snapshot length given that network device is open.
Specified by:
getSnapshotLength in interface PacketCaptureCapable
Following copied from interface: net.sourceforge.jpcap.capture.PacketCaptureCapable
Returns:
the packet snapshot length.