net.sourceforge.jpcap.capture
Interface PacketCaptureCapable

All Known Implementing Classes:

PacketCapture, PacketCaptureSimulator

public interface PacketCaptureCapable

This is the packet capture interface. It is implemented by both the packet capture system (PacketCapture) and the simulator (PacketCaptureSimulator).

The interface has two major components: methods that a client uses to register for packet events and methods that a client calls in order to setup and initiate packet capture.

Field Summary

static int	DEFAULT_SNAPLEN Snapshot length.
static int	DEFAULT_TIMEOUT Default capture timeout in milliseconds.

Method Summary

void	addPacketListener(PacketListener objListener) Register a packet object listener with this capture system.
void	addRawPacketListener(RawPacketListener rawListener) Register a raw packet listener with this capture system.
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.
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	removePacketListener(PacketListener objListener) Deregister a packet object listener from this capture system.
void	removeRawPacketListener(RawPacketListener rawListener) Deregister a raw packet listener from this capture system.
void	setFilter(java.lang.String filterExpression, boolean optimize) Create, compile and activate a filter from a filter expression.

Field Detail

DEFAULT_SNAPLEN

public static final int DEFAULT_SNAPLEN

Snapshot length. Maximum number of bytes per packet to capture. For IPv4, 96 bytes guarantees that at least the headers of most packet types and protocols will get captured. For IPv6, 68 is a better value?

See Also:

Constant Field Values

DEFAULT_TIMEOUT

public static final int DEFAULT_TIMEOUT

Default capture timeout in milliseconds.

See Also:

Constant Field Values

Method Detail

open

public void open(java.lang.String device,
                 boolean promiscuous)
          throws CaptureDeviceOpenException

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.

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.

Throws:

CaptureDeviceOpenException

open

public void open(java.lang.String device,
                 int snaplen,
                 boolean promiscuous,
                 int timeout)
          throws CaptureDeviceOpenException

Open a network device for data capture.

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.

Throws:

CaptureDeviceOpenException

openOffline

public void openOffline(java.lang.String fileName)
                 throws CaptureFileOpenException

Open a tcpdump-formatted savefile.

Parameters:

fileName - the name of the savefile.

Throws:

CaptureFileOpenException

setFilter

public void setFilter(java.lang.String filterExpression,
                      boolean optimize)
               throws InvalidFilterException

Create, compile and activate a filter from a filter expression.

Parameters:

filterExpression - the filter expression. For example, the expression "host techno" would filter only packets sent or arriving at the host named techno.

optimize - whether or not the resulting bpf code is optimized internally by libpcap.

Throws:

InvalidFilterException

capture

public void capture(int count)
             throws CapturePacketException

Capture packets.

Parameters:

count - the number of packets to capture. If count is negative, capture will block forever, unless an exception is thrown.

Throws:

CapturePacketException

getStatistics

public CaptureStatistics getStatistics()

Fetch statistics on captured packets. This method should not be called unless capture() was previously called.

Returns:

packet capture statistics.

close

public void close()

Close the capture device.

findDevice

public java.lang.String findDevice()
                            throws CaptureDeviceNotFoundException

Detect a network device suitable for packet capture.

Returns:

a string describing the network device. if no device can be found, null is returned.

Throws:

CaptureDeviceNotFoundException

getNetwork

public int getNetwork(java.lang.String device)
               throws CaptureConfigurationException

Fetch the network number for the specified device.

Parameters:

device - the name of the network device.

Returns:

the network address

Throws:

CaptureConfigurationException

getNetmask

public int getNetmask(java.lang.String device)
               throws CaptureConfigurationException

Fetch the network mask for the specified device.

Parameters:

device - the name of the network device.

Returns:

the netmask address

Throws:

CaptureConfigurationException

getLinkLayerType

public int getLinkLayerType()
                     throws CaptureConfigurationException

Fetch the link layer type for the specified device.

Returns:

the link layer type code.

Throws:

CaptureConfigurationException

getSnapshotLength

public int getSnapshotLength()

Get the snapshot length given that network device is open.

Returns:

the packet snapshot length.

addRawPacketListener

public void addRawPacketListener(RawPacketListener rawListener)

Register a raw packet listener with this capture system.

Parameters:

rawListener - the raw packet listener to add to the notification list.

removeRawPacketListener

public void removeRawPacketListener(RawPacketListener rawListener)

Deregister a raw packet listener from this capture system.

Parameters:

rawListener - the raw packet listener to remove from the notification list.

addPacketListener

public void addPacketListener(PacketListener objListener)

Register a packet object listener with this capture system.

Parameters:

objListener - the packet listener to add to the notification list.

removePacketListener

public void removePacketListener(PacketListener objListener)

Deregister a packet object listener from this capture system.

Parameters:

objListener - the packet listener to remove from the notification list.