org.jnetpcap.packet
Class JPacket.State

java.lang.Object
  org.jnetpcap.nio.JMemory
      org.jnetpcap.nio.JStruct
          org.jnetpcap.packet.JPacket.State

Enclosing class:

JPacket

public static class JPacket.State
extends JStruct

Class maintains the decoded packet state. The class is peered with struct packet_state_t

 typedef struct packet_state_t {
        uint64_t pkt_header_map; // bit map of presence of headers
        char *pkt_data; // packet data buffer
        int32_t pkt_header_count; // total number of headers found
 
        // Keep track of how many instances of each header we have
        uint8_t pkt_instance_counts[MAX_ID_COUNT];
        header_t pkt_headers[]; // One per header + 1 more for payload
 } packet_t;
 

and struct header_t

 typedef struct header_t {
        int32_t hdr_id; // header ID
        uint32_t hdr_offset; // offset into the packet_t->data buffer
        int32_t hdr_length; // length of the header in packet_t->data buffer
 } header_t;
 
 

The methods in this State provide 3 sets of functions. Looking up global state of the packet found in packet_state_t structure, looking up header information in struct header_t by header ID retrieved from JRegistry and instance numbers, looking up header information by direct indexes into native maps and arrays. Instance numbers specify which instance of the header, if more than 1 exists in a packet. For example if there is a packet with 2 Ip4 headers such as

 Ethernet->Ip4->Snmp->Ip4 
 or 
 Ethernet->Ip4->Ip4 (IP tunneled IP)
 

the first Ip4 header is instance 0 and the second Ip4 header is instance 2. You can use the method getInstanceCount(int) to learn how many instance headers exists. That information is stored in the packet_state_t structure for efficiency.

Author:

Mark Bednarczyk, Sly Technologies, Inc.

Nested Class Summary

Nested classes/interfaces inherited from class org.jnetpcap.nio.JMemory

JMemory.Type

Field Summary

static int	FLAG_TRUNCATED Flag which is set when the packet that was decoded was truncated and not the original length seen on the wire.
static java.lang.String	STRUCT_NAME The Constant STRUCT_NAME.

Fields inherited from class org.jnetpcap.nio.JMemory

JNETPCAP_LIBRARY_NAME, MAX_DIRECT_MEMORY_DEFAULT, POINTER

Constructor Summary

JPacket.State(int size)
Instantiates a new state.

JPacket.State(JMemory.Type type)
Instantiates a new state.

Method Summary

void	cleanup() Cleanup.
int	findHeaderIndex(int id) Find header index.
int	findHeaderIndex(int id, int instance) Find header index.
long	get64BitHeaderMap(int index) Gets the 64 bit header map.
int	getFlags() Gets the 32-bit counter that contains packet's flags in packet_state_t structure.
JFlowKey	getFlowKey() Gets the flow key.
long	getFrameNumber() The frame number is assigned by the scanner at the time of the scan.
int	getHeaderCount() Gets the header count.
int	getHeaderIdByIndex(int index) Gets the header id by index.
int	getHeaderLengthByIndex(int index) A convenience method that gets the length in the packet buffer of the header at specified index.
int	getHeaderOffsetByIndex(int index) A convenience method that gets the offset into the packet buffer of the header at specified index.
int	getInstanceCount(int id) Gets the instance count.
int	getWirelen() Gets the packet's wire length.
int	peer(java.nio.ByteBuffer peer) Peer.
int	peer(JBuffer peer) Peer.
int	peer(JBuffer peer, int offset, int length) Peer.
int	peer(JMemory memory, int offset) Peer.
int	peer(JMemoryPool.Block peer, int offset, int length) Peer.
int	peer(JPacket.State peer) Peer.
int	peerHeaderById(int id, int instance, JHeader.State dst) Peer header by id.
int	peerHeaderByIndex(int index, JHeader.State dst) Peer header by index.
int	peerTo(JBuffer buffer, int offset) Peers this packet's state to buffer.
int	peerTo(JBuffer buffer, int offset, int size) Peers this packet's state to buffer.
int	peerTo(JPacket.State state, int offset) Peer to.
void	setFlags(int flags) Sets the 32-bit counter with packet flags.
void	setWirelen(int length) Sets the packet's wire length.
static int	sizeof(int count) Sizeof.
java.lang.String	toDebugString() Dump packet_state_t structure and its sub structures to textual debug output
int	transferTo(byte[] dst, int dstOffset) Transfer to.
int	transferTo(byte[] dst, int srcOffset, int length, int dstOffset) Transfer to.
int	transferTo(JBuffer dst, int srcOffset, int length, int dstOffset) Transfer to.
int	transferTo(JPacket.State dst) Transfer to.

Methods inherited from class org.jnetpcap.nio.JStruct

getStructName, toString

Methods inherited from class org.jnetpcap.nio.JMemory

availableDirectMemory, check, createReference, isInitialized, isJMemoryBasedOwner, isOwner, maxDirectMemory, peer, peer, reservedDirectMemory, setSize, size, softDirectMemory, toHexdump, toHexdump, totalActiveAllocated, totalAllocateCalls, totalAllocated, totalAllocatedSegments0To255Bytes, totalAllocatedSegments256OrAbove, totalDeAllocateCalls, totalDeAllocated, transferFrom, transferFrom, transferFrom, transferFrom, transferFromDirect, transferOwnership, transferTo, transferTo, transferTo, transferTo, transferTo, transferTo0

Methods inherited from class java.lang.Object

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

Field Detail

FLAG_TRUNCATED

public static final int FLAG_TRUNCATED

Flag which is set when the packet that was decoded was truncated and not the original length seen on the wire.

See Also:

Constant Field Values

STRUCT_NAME

public static final java.lang.String STRUCT_NAME

The Constant STRUCT_NAME.

See Also:

Constant Field Values

Constructor Detail

JPacket.State

public JPacket.State(int size)

Instantiates a new state.

Parameters:

size - the size

JPacket.State

public JPacket.State(JMemory.Type type)

Instantiates a new state.

Parameters:

type - the type

Method Detail

sizeof

public static int sizeof(int count)

Sizeof.

Parameters:

count - header counter, number of headers to calaculate in

Returns:

size in bytes

cleanup

public void cleanup()

Cleanup.

Overrides:

cleanup in class JMemory

See Also:

JMemory.cleanup()

findHeaderIndex

public int findHeaderIndex(int id)

Find header index.

Parameters:

id - the id

Returns:

the int

findHeaderIndex

public int findHeaderIndex(int id,
                           int instance)

Find header index.

Parameters:

id - the id

instance - the instance

Returns:

the int

get64BitHeaderMap

public long get64BitHeaderMap(int index)

Gets the 64 bit header map.

Parameters:

index - TODO: remove index, its no longer used natively

Returns:

the 64 bit header map

getFlags

public int getFlags()

Gets the 32-bit counter that contains packet's flags in packet_state_t structure.

Returns:

bit flags for this packet

getFlowKey

public JFlowKey getFlowKey()

Gets the flow key.

Returns:

the flow key

getFrameNumber

public long getFrameNumber()

The frame number is assigned by the scanner at the time of the scan. Therefore number is only unique within the same scanner.

Returns:

frame number

getHeaderCount

public int getHeaderCount()

Gets the header count.

Returns:

the header count

getHeaderIdByIndex

public int getHeaderIdByIndex(int index)

Gets the header id by index.

Parameters:

index - the index

Returns:

the header id by index

getHeaderLengthByIndex

public int getHeaderLengthByIndex(int index)

A convenience method that gets the length in the packet buffer of the header at specified index. Typically header information is retrieved using JHeader.State structure which can access all available header information.

Parameters:

index - header index

Returns:

length in bytes of the header

getHeaderOffsetByIndex

public int getHeaderOffsetByIndex(int index)

A convenience method that gets the offset into the packet buffer of the header at specified index. Typically header information is retrieved using JHeader.State structure which can access all available header information.

Parameters:

index - header index

Returns:

offset in bytes of the start of the header

getInstanceCount

public int getInstanceCount(int id)

Gets the instance count.

Parameters:

id - the id

Returns:

the instance count

getWirelen

public int getWirelen()

Gets the packet's wire length.

Returns:

original length of the packet

peer

public int peer(java.nio.ByteBuffer peer)
         throws PeeringException

Peer.

Overrides:

peer in class JMemory

Parameters:

peer - the peer

Returns:

the int

Throws:

PeeringException - the peering exception

See Also:

JMemory.peer(java.nio.ByteBuffer)

peer

public int peer(JBuffer peer)

Peer.

Parameters:

peer - the peer

Returns:

the int

peer

public int peer(JBuffer peer,
                int offset,
                int length)
         throws java.lang.IndexOutOfBoundsException

Peer.

Parameters:

peer - the peer

offset - the offset

length - the length

Returns:

the int

Throws:

java.lang.IndexOutOfBoundsException - the index out of bounds exception

peer

public int peer(JMemory memory,
                int offset)

Peer.

Parameters:

memory - the memory

offset - the offset

Returns:

the int

peer

public int peer(JMemoryPool.Block peer,
                int offset,
                int length)
         throws java.lang.IndexOutOfBoundsException

Peer.

Parameters:

peer - the peer

offset - the offset

length - the length

Returns:

the int

Throws:

java.lang.IndexOutOfBoundsException - the index out of bounds exception

peer

public int peer(JPacket.State peer)

Peer.

Parameters:

peer - the peer

Returns:

the int

peerHeaderById

public int peerHeaderById(int id,
                          int instance,
                          JHeader.State dst)

Peer header by id.

Parameters:

id - the id

instance - the instance

dst - the dst

Returns:

the int

peerHeaderByIndex

public int peerHeaderByIndex(int index,
                             JHeader.State dst)
                      throws java.lang.IndexOutOfBoundsException

Peer header by index.

Parameters:

index - the index

dst - the dst

Returns:

the int

Throws:

java.lang.IndexOutOfBoundsException - the index out of bounds exception

peerTo

public int peerTo(JBuffer buffer,
                  int offset)

Peers this packet's state to buffer.

Parameters:

buffer - source buffer

offset - offset into the buffer

Returns:

number of bytes peered

peerTo

public int peerTo(JBuffer buffer,
                  int offset,
                  int size)

Peers this packet's state to buffer.

Parameters:

buffer - source buffer

offset - offset into the buffer

size - specifies the number of bytes to peer

Returns:

number of bytes peered

peerTo

public int peerTo(JPacket.State state,
                  int offset)

Peer to.

Parameters:

state - the state

offset - the offset

Returns:

the int

setFlags

public void setFlags(int flags)

Sets the 32-bit counter with packet flags.

Parameters:

flags - bit flags for this packet

setWirelen

public void setWirelen(int length)

Sets the packet's wire length.

Parameters:

length - the original length of the packet before truncation

toDebugString

public java.lang.String toDebugString()

Dump packet_state_t structure and its sub structures to textual debug output

Explanation:

 sizeof(packet_state_t)=16
 sizeof(header_t)=8 and *4=32
 pkt_header_map=0x1007         // bitmap, each bit represets a header
 pkt_header_count=4            // how many header found
 // per header information (4 header found in this example)
 pkt_headers[0]=<hdr_id=1  ETHERNET ,hdr_offset=0  ,hdr_length=14>
 pkt_headers[1]=<hdr_id=2  IP4      ,hdr_offset=14 ,hdr_length=60>
 pkt_headers[2]=<hdr_id=12 ICMP     ,hdr_offset=74 ,hdr_length=2>
 pkt_headers[3]=<hdr_id=0  PAYLOAD  ,hdr_offset=76 ,hdr_length=62>
 
 // hdr_id = numerical ID of the header, asssigned by JRegistry
 // hdr_offset = offset in bytes into the packet buffer
 // hdr_length = length in bytes of the entire header
 

Packet state is made up of 2 structures: packet_stat_t and an array of header_t, one per header. Total size in bytes is all of the header structures combined, that is 16 + 32 = 48 bytes. Each bit in the header_map represents the presence of that header type. The index of the bit is the numerical ID of the header. If 2 headers of the same type are present, they are both represented by a single bit in the bitmap. This way the implementation JPacket.hasHeader(int id) is a simple bit operation to test if the header is present or not.

Overrides:

toDebugString in class JMemory

Returns:

multiline string containing dump of the entire structure

transferTo

public int transferTo(byte[] dst,
                      int dstOffset)

Transfer to.

Parameters:

dst - the dst

dstOffset - the dst offset

Returns:

the int

transferTo

public int transferTo(byte[] dst,
                      int srcOffset,
                      int length,
                      int dstOffset)

Transfer to.

Overrides:

transferTo in class JMemory

Parameters:

dst - the dst

srcOffset - the src offset

length - the length

dstOffset - the dst offset

Returns:

the int

See Also:

JMemory.transferTo(byte[], int, int, int)

transferTo

public int transferTo(JBuffer dst,
                      int srcOffset,
                      int length,
                      int dstOffset)

Transfer to.

Overrides:

transferTo in class JMemory

Parameters:

dst - the dst

srcOffset - the src offset

length - the length

dstOffset - the dst offset

Returns:

the int

See Also:

JMemory.transferTo(org.jnetpcap.nio.JBuffer, int, int, int)

transferTo

public int transferTo(JPacket.State dst)

Transfer to.

Parameters:

dst - the dst

Returns:

the int