net.sourceforge.jpcap.net
Class IPv4.Packet

java.lang.Object
  net.sourceforge.jpcap.net.Packet
      net.sourceforge.jpcap.net.EthernetPacket
          net.sourceforge.jpcap.net.IP.Packet
              net.sourceforge.jpcap.net.IPv4.Packet

All Implemented Interfaces:

Serializable, EthernetFields, IPFields

Direct Known Subclasses:

IPPacket, IPv4.TCP.Packet, IPv4.UDP.Packet

Enclosing interface:

IPv4

public abstract static class IPv4.Packet
extends IP.Packet
implements IPFields

Base IPv4 packet class.

Since:

2.0.0.

Version:

$Revision: 1.1 $

Author:

Esmond Pitt

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sourceforge.jpcap.net.IP.Packet

_ipHeaderLength, _ipOffset

Fields inherited from class net.sourceforge.jpcap.net.EthernetPacket

_byteBuffer, _bytes, _ethOffset, _timeval

Fields inherited from interface net.sourceforge.jpcap.net.IPFields

IP_CODE_LEN, IP_CODE_POS, IP_CSUM_LEN, IP_CSUM_POS, IP_DST_POS, IP_FRAG_LEN, IP_FRAG_POS, IP_HEADER_LEN, IP_ID_LEN, IP_ID_POS, IP_LEN_LEN, IP_LEN_POS, IP_SRC_POS, IP_TOS_LEN, IP_TOS_POS, IP_TTL_LEN, IP_TTL_POS, IP_VER_LEN, IP_VER_POS

Fields inherited from interface net.sourceforge.jpcap.net.EthernetFields

ETH_CODE_LEN, ETH_CODE_POS, ETH_DST_POS, ETH_HEADER_LEN, ETH_SRC_POS

Constructor Summary

IPv4.Packet(int lLen, byte[] bytes)

IPv4.Packet(int lLen, byte[] bytes, Timeval tv)

IPv4.Packet(int lLen, ByteBuffer bb, Timeval tv)

Method Summary

protected int	computeReceiverChecksum(int start, int len)
protected int	computeReceiverIPChecksum()
protected int	computeSenderChecksum(int start, int len, int csumPos)
protected int	computeSenderIPChecksum()
int	getChecksum() Return the actual packet checksum as received.
InetAddress	getDestinationInetAddress() Fetch the destination IP address.
int	getFragmentFlags() Fetch fragmentation flags.
int	getFragmentOffset() Fetch fragment offset.
int	getId() Fetch the unique ID of this IP packet.
int	getIPChecksum() Fetch the IP checksum.
byte[]	getIPData() Fetch the IP data as a byte array.
byte[]	getIPHeader() Fetch the IP header as a byte array.
int	getIPHeaderLength() Fetch the IP header length in bytes.
int	getIPProtocol() Fetch the code indicating the type of protocol embedded in the IP packet.
int	getLength() Fetch the IP payload length in bytes.
int	getProtocol() Return the protocol. This is overridden by derived classes: for example: EthernetPacket.getProtocol() returns the Ethernet protocol word. getProtocol() returns the IP protocol word
InetAddress	getSourceInetAddress() Fetch the source IP address.
int	getTimeToLive() Fetch the time to live.
int	getTypeOfService() Fetch the type of service.
int	getVersion() Get the IP version code.
boolean	isValidChecksum() Return true iff all the checksums in the packet are valid, otherwise false.
boolean	isValidIPChecksum() Check if the IP packet is valid, checksum-wise.
void	setChecksums() Set all the checksums in this packet prior to sending. Calling this method sets all the IP, ICMP, IGMP, TCP, UDP etc checksums as appropriate. It is called automatically by PacketOutputStream.writePacket(Packet). Derived classes must override this abstract method, and must call super.setChecksums(), after setting their own checksums (unless super.setChecksums() is abstract, i.e. this method). Otherwise the lower-level checksums will not be correct.
void	setDestinationInetAddress(InetAddress address) Set the destination address.
void	setSourceInetAddress(InetAddress address) Set the source address.
String	toColoredVerboseString(boolean colored) Convert this IP packet to a more verbose string.

Methods inherited from class net.sourceforge.jpcap.net.IP.Packet

getColor, getData, getHeader, getHeaderLength, toColoredString

Methods inherited from class net.sourceforge.jpcap.net.EthernetPacket

equals, getDestinationHwAddress, getDestinationMACAddress, getEthernetCRC32, getEthernetData, getEthernetHeader, getEthernetHeaderLength, getEthernetProtocol, getPacketData, getPacketLength, getSourceHwAddress, getSourceMACAddress, getTimeval, hashCode, setDestinationMACAddress, setEthernetProtocol, setSourceMACAddress, toByteArray, toString

Methods inherited from class net.sourceforge.jpcap.net.Packet

ipChecksum

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

IPv4.Packet

public IPv4.Packet(int lLen,
                   byte[] bytes)

IPv4.Packet

public IPv4.Packet(int lLen,
                   byte[] bytes,
                   Timeval tv)

IPv4.Packet

public IPv4.Packet(int lLen,
                   ByteBuffer bb,
                   Timeval tv)

Method Detail

getVersion

public int getVersion()

Description copied from class: IP.Packet

Get the IP version code.

Specified by:

getVersion in class IP.Packet

Returns:

the IP version (4 or 6).

getIPHeaderLength

public int getIPHeaderLength()

Description copied from class: IP.Packet

Fetch the IP header length in bytes.

Specified by:

getIPHeaderLength in class IP.Packet

Returns:

the IP header length in bytes

getTypeOfService

public int getTypeOfService()

Fetch the type of service. For more information refer to the TypesOfService interface.

Returns:

the type of service.

See Also:

TypesOfService

getLength

public int getLength()

Description copied from class: IP.Packet

Fetch the IP payload length in bytes.

Specified by:

getLength in class IP.Packet

Returns:

the IP payload length in bytes.

getId

public int getId()

Fetch the unique ID of this IP packet. The ID normally increments by one each time a packet is sent by a host.

Returns:

the unique packet ID

getFragmentFlags

public int getFragmentFlags()

Fetch fragmentation flags.

Returns:

the fragmentation flags

getFragmentOffset

public int getFragmentOffset()

Fetch fragment offset.

Returns:

the fragment offset

getTimeToLive

public int getTimeToLive()

Fetch the time to live. TTL sets the upper limit on the number of routers through which this IP datagram is allowed to pass.

Returns:

the TTL

getIPProtocol

public int getIPProtocol()

Description copied from class: IP.Packet

Fetch the code indicating the type of protocol embedded in the IP packet.

Specified by:

getIPProtocol in class IP.Packet

Returns:

the IP protocol identifier.

See Also:

IPProtocols

getProtocol

public int getProtocol()

Return the protocol. This is overridden by derived classes: for example:

• EthernetPacket.getProtocol() returns the Ethernet protocol word.
• getProtocol() returns the IP protocol word

Overrides:

getProtocol in class EthernetPacket

Returns:

the protocol word.

getIPChecksum

public int getIPChecksum()

Fetch the IP checksum.

Returns:

the IP checksum

getChecksum

public int getChecksum()

Return the actual packet checksum as received. Derived classes override this to return the most specific checksum, e.g.:

• getChecksum() returns the IP checksum
• TCPPacket.getChecksum() returns the TCP checksum

The implementation in Packet.getChecksum() returns zero.

Overrides:

getChecksum in class Packet

getSourceInetAddress

public InetAddress getSourceInetAddress()

Description copied from class: IP.Packet

Fetch the source IP address.

Specified by:

getSourceInetAddress in class IP.Packet

Returns:

the source IP address

setSourceInetAddress

public void setSourceInetAddress(InetAddress address)

Description copied from class: IP.Packet

Set the source address.

Specified by:

setSourceInetAddress in class IP.Packet

Parameters:

address - Source address.

getDestinationInetAddress

public InetAddress getDestinationInetAddress()

Description copied from class: IP.Packet

Fetch the destination IP address.

Specified by:

getDestinationInetAddress in class IP.Packet

Returns:

the destination IP address

setDestinationInetAddress

public void setDestinationInetAddress(InetAddress address)

Description copied from class: IP.Packet

Set the destination address.

Specified by:

setDestinationInetAddress in class IP.Packet

Parameters:

address - Destination address.

getIPHeader

public byte[] getIPHeader()

Description copied from class: IP.Packet

Fetch the IP header as a byte array.

Specified by:

getIPHeader in class IP.Packet

Returns:

the IP header

getIPData

public byte[] getIPData()

Description copied from class: IP.Packet

Fetch the IP data as a byte array.

Specified by:

getIPData in class IP.Packet

Returns:

the IP payload

isValidChecksum

public boolean isValidChecksum()

Return true iff all the checksums in the packet are valid, otherwise false. Derived classes with checksums should override, and should call super.isValidChecksum() to check the validity of base class checksums. The Packet.isValidChecksum() implementation just returns true.

Overrides:

isValidChecksum in class Packet

Returns:

true iff all the checksums in the packet are valid.

isValidIPChecksum

public boolean isValidIPChecksum()

Check if the IP packet is valid, checksum-wise.

Returns:

true iff the IP checksum is valid.

computeReceiverIPChecksum

protected int computeReceiverIPChecksum()

computeReceiverChecksum

protected int computeReceiverChecksum(int start,
                                      int len)

computeSenderIPChecksum

protected int computeSenderIPChecksum()

computeSenderChecksum

protected int computeSenderChecksum(int start,
                                    int len,
                                    int csumPos)

setChecksums

public void setChecksums()

Set all the checksums in this packet prior to sending. Calling this method sets all the IP, ICMP, IGMP, TCP, UDP etc checksums as appropriate. It is called automatically by PacketOutputStream.writePacket(Packet). Derived classes must override this abstract method, and must call super.setChecksums(), after setting their own checksums (unless super.setChecksums() is abstract, i.e. this method). Otherwise the lower-level checksums will not be correct.

After calling this method the EthernetPacket.hashCode() of this object will probably change.

Overrides:

setChecksums in class EthernetPacket

toColoredVerboseString

public String toColoredVerboseString(boolean colored)

Description copied from class: IP.Packet

Convert this IP packet to a more verbose string.

Specified by:

toColoredVerboseString in class IP.Packet