org.jnetpcap.winpcap
Class WinPcapSendQueue

java.lang.Object
  org.jnetpcap.winpcap.WinPcapSendQueue

public class WinPcapSendQueue
extends java.lang.Object

Class peered with native pcap_send_queue structure. A queue of raw packets that will be sent to the network with WinPcap.sendqueueTransmit(). The class peers with native C pcap_send_queue structure and allows direct control. The structure can be allocated using WinPcap.sendQueueAlloc method or can be directly instantiated using one o the public constructors.

Author:

Mark Bednarczyk, Sly Technologies, Inc.

Field Summary

static int

DEFAULT_QUEUE_SIZE Constant used to determine the default queue size which is 64Kb (1024 * 64).

Constructor Summary

WinPcapSendQueue()
Allocates default size buffer for use as a send queue.

WinPcapSendQueue(byte[] data)
Creates a sendqueue by allocating a buffer to hold the supplied data.

WinPcapSendQueue(java.nio.ByteBuffer buffer)
The queue uses the supplied byte buffer which holds the buffers contents.

WinPcapSendQueue(int size)
Allocates specific queue size

Method Summary

java.nio.ByteBuffer	getBuffer() Gets the buffer containing the packets to be sent.
int	getLen() Gets the current size of the queue, in bytes.
int	getMaxLen() Gets the maximum size of the the queue, in bytes.
int	queue(PcapPktHdr hdr, byte[] data) Add a packet to a send queue.
int	queue(PcapPktHdr hdr, java.nio.ByteBuffer data) Add a packet to a send queue.
void	setLen(int len) Sets the peered pcap_send_queue.len field which specifies the urrent size of the queue, in bytes.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_QUEUE_SIZE

public static final int DEFAULT_QUEUE_SIZE

Constant used to determine the default queue size which is 64Kb (1024 * 64).

See Also:

Constant Field Values

Constructor Detail

WinPcapSendQueue

public WinPcapSendQueue()

Allocates default size buffer for use as a send queue.

WinPcapSendQueue

public WinPcapSendQueue(int size)

Allocates specific queue size

Parameters:

size - size of the queue in bytes

WinPcapSendQueue

public WinPcapSendQueue(java.nio.ByteBuffer buffer)

The queue uses the supplied byte buffer which holds the buffers contents. The buffer must a direct buffer, array based buffers will be rejected and an exception thrown. The properties of the buffer are used as follows. The start of the buffer is always with index 0, and end of queue content at current buffer's limit property (comparible to pcap_send_queue.len). The capacity property (comparible to pcap_send_queue.maxlen) determines maximum amount of data that can be further stored in the buffer.

Note that changing properties of the buffer after creating this queue object, will have immediate effect up on the queue. You do not have to use the queue's provided methods to change the limit property. This should allow of external addition of the

Parameters:

buffer - a direct buffer containing the data to be send

WinPcapSendQueue

public WinPcapSendQueue(byte[] data)

Creates a sendqueue by allocating a buffer to hold the supplied data. The data array is copied into the buffer.

Parameters:

data - data to be copied into the queue

Method Detail

setLen

public void setLen(int len)

Sets the peered pcap_send_queue.len field which specifies the urrent size of the queue, in bytes.

Parameters:

len - current size of the queue, in bytes

getLen

public int getLen()

Gets the current size of the queue, in bytes.

Returns:

current size of the queue, in bytes

getMaxLen

public int getMaxLen()

Gets the maximum size of the the queue, in bytes. This variable contains the size of the buffer field.

Returns:

maximum size of the the queue, in bytes

getBuffer

public java.nio.ByteBuffer getBuffer()

Gets the buffer containing the packets to be sent.

Returns:

buffer containing the packets to be sent

queue

public int queue(PcapPktHdr hdr,
                 java.nio.ByteBuffer data)

Add a packet to a send queue. This method adds a packet at the end of the send queue pointed by the queue parameter. hdr points to a PcapPktHdr structure with the timestamp and the length of the packet, data points to a buffer with the data of the packet. The PcapPktHdr structure is the same used by WinPcap and libpcap to store the packets in a file, therefore sending a capture file is straightforward. 'Raw packet' means that the sending application will have to include the protocol headers, since every packet is sent to the network 'as is'. The CRC of the packets needs not to be calculated, because it will be transparently added by the network interface.

Parameters:

hdr - all fields need to be initialized as they are all used

data - Buffer containing packet data. The buffer's position and limit properties determine the area of the buffer to be copied into the queue. The length of the data must much what is in the header. Also the queue has to be large enough to hold all of the data, or an exception will be thrown.

Returns:

0 on success; exception thrown on failure

Throws:

java.lang.IllegalArgumentException - if amount of data in the buffer (limit - position) does match the hdr.getCaplen() value

java.nio.BufferUnderflowException - if the queues buffer capacity is too small to hold all of the data

queue

public int queue(PcapPktHdr hdr,
                 byte[] data)

Add a packet to a send queue. This method adds a packet at the end of the send queue pointed by the queue parameter. hdr points to a PcapPktHdr structure with the timestamp and the length of the packet, data points to a buffer with the data of the packet. The PcapPktHdr structure is the same used by WinPcap and libpcap to store the packets in a file, therefore sending a capture file is straightforward. 'Raw packet' means that the sending application will have to include the protocol headers, since every packet is sent to the network 'as is'. The CRC of the packets needs not to be calculated, because it will be transparently added by the network interface.

Parameters:

hdr - all fields need to be initialized as they are all used

data - Buffer containing packet data. The length of the data must much what is in the header. Also the queue has to be large enough to hold all of the data, or an exception will be thrown.

Returns:

0 on success; exception thrown on failure

Throws:

java.lang.IllegalArgumentException - if amount of data does match the hdr.getCaplen() value

java.nio.BufferUnderflowException - if the queues buffer capacity is too small to hold all of the data