io.pkts.packet

Interface IPv4Packet

All Superinterfaces:

Cloneable, IPPacket, Packet

All Known Implementing Classes:

IPv4PacketImpl

public interface IPv4Packet
extends IPPacket

Represents a packet from the Network Layer (layer 3). Actually, to be completely honest, the model implemented (at least so far) is more geared towards what is commonly referred to as the Internet Layer and is strictly speaking not quite the same as the Network Layer as specified by the OSI model. However, until it becomes an issue this little "issue" is going to be ignored and for now the Network Layer is equal to the Internet Layer. The current version of pkts.io is focused on IP anyway so...

Author:

jonas@jonasborjesson.com

Method Summary

Modifier and Type	Method and Description
IPv4Packet	clone()
short	getDSCP()
short	getECN()
short	getFragmentOffset() The fragment offset field, measured in units of eight-byte blocks, is 13 bits long and specifies the offset of a particular fragment relative to the beginning of the original unfragmented IP datagram.
int	getIpChecksum() The checksum of the IP-packet.
int	getTimeToLive()
boolean	isDontFragmentSet() The DF flag is part of the three-bit flag field and those flags are: (in order, from high order to low order):
boolean	isFragmented()
boolean	isMoreFragmentsSet() The MF flag is part of the three-bit flag field and those flags are: (in order, from high order to low order):
boolean	isReservedFlagSet() The Reserved flag is part of the three-bit flag field and those flags are: (in order, from high order to low order):
void	reCalculateChecksum() After you change anything in an IP packet (apart from the payload) you should re-calculate the checksum.
void	setDestinationIP(byte a, byte b, byte c, byte d)
void	setDestinationIP(int a, int b, int c, int d) Setting an IPv4 address the fast way! Specify each part separately.
void	setDestinationIP(String destinationIP) Set the destination IP of this IPv4Packet.
void	setSourceIP(byte a, byte b, byte c, byte d) Setting an IPv4 address the fast(est?) way! Specify each part separately.
void	setSourceIP(int a, int b, int c, int d) Setting an IPv4 address the fast way! Specify each part separately.
void	setSourceIP(String sourceIp) Set the source IP of this IPv4Packet.
boolean	verifyIpChecksum()

Methods inherited from interface io.pkts.packet.IPPacket

getDestinationIP, getHeaderLength, getIdentification, getRawDestinationIP, getRawSourceIP, getSourceIP, getTotalIPLength, getVersion

Methods inherited from interface io.pkts.packet.Packet

getArrivalTime, getName, getNextPacket, getPacket, getParentPacket, getPayload, getProtocol, hasProtocol, verify, write, write

Method Detail

setSourceIP

void setSourceIP(int a,
                 int b,
                 int c,
                 int d)

Setting an IPv4 address the fast way! Specify each part separately. E.g., setting 192.168.0.100 would be accomplished like so: #setSourceIP(192, 168, 0, 100)

Parameters:

a - the first part of the IPv4 address, e.g. 192

b - the second part of the IPv4 address, e.g. 168

c - the third part of the IPv4 address, e.g. 0

d - the fourth part of the IPv4 address, e.g. 100

setSourceIP

void setSourceIP(byte a,
                 byte b,
                 byte c,
                 byte d)

Setting an IPv4 address the fast(est?) way! Specify each part separately. E.g., setting 192.168.0.100 would be accomplished like so:

Parameters:

rawIp -

setSourceIP

void setSourceIP(String sourceIp)

Set the source IP of this IPv4Packet. Note, using setSourceIP(int, int, int, int) will be must faster so try and use it instead.

Specified by:

setSourceIP in interface IPPacket

Parameters:

sourceIp -

setDestinationIP

void setDestinationIP(int a,
                      int b,
                      int c,
                      int d)

Setting an IPv4 address the fast way! Specify each part separately. E.g., setting 192.168.0.100 would be accomplished like so: #setSourceIP(192, 168, 0, 100)

Parameters:

a - the first part of the IPv4 address, e.g. 192

b - the second part of the IPv4 address, e.g. 168

c - the third part of the IPv4 address, e.g. 0

d - the fourth part of the IPv4 address, e.g. 100

setDestinationIP

void setDestinationIP(byte a,
                      byte b,
                      byte c,
                      byte d)

setDestinationIP

void setDestinationIP(String destinationIP)

Set the destination IP of this IPv4Packet. Note, using setDestinationIP(int, int, int, int) will be must faster so try and use it instead.

Specified by:

setDestinationIP in interface IPPacket

Parameters:

sourceIp -

getIpChecksum

int getIpChecksum()

The checksum of the IP-packet. The checksum in an IP-packet is a 16 bit checksum of the header bytes (which the checksum set to zero) and is returned as a unsigned short (hence an int) Checkout

Returns:

reCalculateChecksum

void reCalculateChecksum()

After you change anything in an IP packet (apart from the payload) you should re-calculate the checksum. If you don't, if this then is written to a pcap and later opened in e.g. wireshark, then all packets will be flagged as bad checksums.

verifyIpChecksum

boolean verifyIpChecksum()

getTimeToLive

int getTimeToLive()

getDSCP

short getDSCP()

getECN

short getECN()

clone

IPv4Packet clone()

Specified by:

clone in interface IPPacket

Specified by:

clone in interface Packet

isFragmented

boolean isFragmented()

Specified by:

isFragmented in interface IPPacket

Returns:

isReservedFlagSet

boolean isReservedFlagSet()

The Reserved flag is part of the three-bit flag field and those flags are: (in order, from high order to low order):

 bit 0: Reserved; must be zero.
 bit 1: Don't Fragment (DF)
 bit 2: More Fragments (MF)
 

(source http://en.wikipedia.org/wiki/IPv4)

Returns:

should always return false

isDontFragmentSet

boolean isDontFragmentSet()

The DF flag is part of the three-bit flag field and those flags are: (in order, from high order to low order):

 bit 0: Reserved; must be zero.
 bit 1: Don't Fragment (DF)
 bit 2: More Fragments (MF)
 

If the DF flag is set, and fragmentation is required to route the packet, then the packet is dropped. This can be used when sending packets to a host that does not have sufficient resources to handle fragmentation. It can also be used for Path MTU Discovery, either automatically by the host IP software, or manually using diagnostic tools such as ping or traceroute. For unfragmented packets, the MF flag is cleared. For fragmented packets, all fragments except the last have the MF flag set. The last fragment has a non-zero Fragment Offset field, differentiating it from an unfragmented packet. (source http://en.wikipedia.org/wiki/IPv4)

Returns:

isMoreFragmentsSet

boolean isMoreFragmentsSet()

The MF flag is part of the three-bit flag field and those flags are: (in order, from high order to low order):

 bit 0: Reserved; must be zero.
 bit 1: Don't Fragment (DF)
 bit 2: More Fragments (MF)
 

If the DF flag is set, and fragmentation is required to route the packet, then the packet is dropped. This can be used when sending packets to a host that does not have sufficient resources to handle fragmentation. It can also be used for Path MTU Discovery, either automatically by the host IP software, or manually using diagnostic tools such as ping or traceroute. For unfragmented packets, the MF flag is cleared. For fragmented packets, all fragments except the last have the MF flag set. The last fragment has a non-zero Fragment Offset field, differentiating it from an unfragmented packet. (source http://en.wikipedia.org/wiki/IPv4)

Returns:

getFragmentOffset

short getFragmentOffset()

The fragment offset field, measured in units of eight-byte blocks, is 13 bits long and specifies the offset of a particular fragment relative to the beginning of the original unfragmented IP datagram. The first fragment has an offset of zero. This allows a maximum offset of (213 – 1) × 8 = 65,528 bytes, which would exceed the maximum IP packet length of 65,535 bytes with the header length included (65,528 + 20 = 65,548 bytes). (source http://en.wikipedia.org/wiki/IPv4)

Specified by:

getFragmentOffset in interface IPPacket

Returns: