pcpp::PacketTrailerLayer Class Reference

#include <PacketTrailerLayer.h>

Inheritance diagram for pcpp::PacketTrailerLayer:

Public Member Functions
	PacketTrailerLayer (uint8_t *data, size_t dataLen, Layer *prevLayer, Packet *packet)
uint8_t *	getTrailerData () const
std::string	getTrailerDataAsHexString () const
size_t	getTrailerLen () const
void	parseNextLayer () override
	Does nothing for this layer (PacketTrailerLayer is always last)
size_t	getHeaderLen () const override
void	computeCalculateFields () override
	Does nothing for this layer.
std::string	toString () const override
OsiModelLayer	getOsiModelLayer () const override
Public Member Functions inherited from pcpp::Layer
	~Layer () override
Layer *	getNextLayer () const
Layer *	getPrevLayer () const
ProtocolType	getProtocol () const
bool	isMemberOfProtocolFamily (ProtocolTypeFamily protocolTypeFamily) const
uint8_t *	getData () const
size_t	getDataLen () const
uint8_t *	getLayerPayload () const
size_t	getLayerPayloadSize () const
bool	isAllocatedToPacket () const
void	copyData (uint8_t *toArr) const
uint8_t *	getDataPtr (size_t offset=0) const override

Additional Inherited Members
Protected Member Functions inherited from pcpp::Layer
Packet *	getAttachedPacket ()
	Get a pointer to the Packet this layer is attached to (if any). More...
Packet const *	getAttachedPacket () const
	Get a pointer to the Packet this layer is attached to (if any). More...
template<typename T , typename... Args>
Layer *	constructNextLayer (uint8_t *data, size_t dataLen, Args &&... extraArgs)
	Construct the next layer in the protocol stack. No validation is performed on the data. More...
template<typename T , typename... Args>
Layer *	constructNextLayer (uint8_t *data, size_t dataLen, Packet *packet, Args &&... extraArgs)
template<typename TFactory , typename... Args>
Layer *	constructNextLayerFromFactory (TFactory factoryFn, uint8_t *data, size_t dataLen, Args &&... extraArgs)
	Construct the next layer in the protocol stack using a factory functor. More...
template<typename TFactory , typename... Args>
Layer *	constructNextLayerFromFactory (TFactory factoryFn, uint8_t *data, size_t dataLen, Packet *packet, Args &&... extraArgs)
	Construct the next layer in the protocol stack using a factory functor. More...
template<typename T , typename... Args>
Layer *	tryConstructNextLayer (uint8_t *data, size_t dataLen, Args &&... extraArgs)
template<typename T , typename... Args>
Layer *	tryConstructNextLayer (uint8_t *data, size_t dataLen, Packet *packet, Args &&... extraArgs)
template<typename T , typename TFallback , typename... Args>
Layer *	tryConstructNextLayerWithFallback (uint8_t *data, size_t dataLen, Args &&... extraArgs)
	Try to construct the next layer in the protocol stack with a fallback option. More...
template<typename T , typename TFallback , typename... Args>
Layer *	tryConstructNextLayerWithFallback (uint8_t *data, size_t dataLen, Packet *packet, Args &&... extraArgs)
template<typename TFallback , typename TFactory , typename... Args>
Layer *	tryConstructNextLayerFromFactoryWithFallback (TFactory factoryFn, uint8_t *data, size_t dataLen, Args &&... extraArgs)
	Try to construct the next layer in the protocol stack using a factory functor with a fallback option. More...
template<typename TFallback , typename TFactory , typename... Args>
Layer *	tryConstructNextLayerFromFactoryWithFallback (TFactory factoryFn, uint8_t *data, size_t dataLen, Packet *packet, Args &&... extraArgs)
	Try to construct the next layer in the protocol stack using a factory functor with a fallback option. More...
Static Protected Member Functions inherited from pcpp::Layer
template<typename T >
static bool	canReinterpretAs (const uint8_t *data, size_t dataLen)
	Check if the data is large enough to reinterpret as a type. More...

Detailed Description

A class for representing packet trailer (a.k.a footer or padding) which refers to supplemental data placed at the end of a block of data being stored or transmitted, which may contain information for the handling of the data block, or just mark its end (taken from Wikipedia: https://en.wikipedia.org/wiki/Trailer_(computing) )

There are various reasons for adding a packet trailer, one of the most famous is FCS (Frame check sequence) which refers to the extra error-detecting code added to a frame. Another usage is padding which means adding data to reach a minimum required packet length.

Although this layer inherits from the Layer class, it is not a standard layer in the sense that it can't be constructed by the user. This layer may be only be constructed in the Packet class, in the process of parsing the packet and creating the layers; if at the end of the parsing process there is data left that is not allocated to any layer, it's assumed to be the packet trailer and an instance of this class is created. This means this layer can only exist as the last layer in a packet, if a packet trailer indeed exists.

No layer can be added by the user after this layer (trying to do that will result with an error).

This layer can be removed by the user or extended/shortened, as any layer.

It also contains method to extract the trailer data

Constructor & Destructor Documentation

PacketTrailerLayer()

pcpp::PacketTrailerLayer::PacketTrailerLayer ( uint8_t *  data, size_t  dataLen, Layer *  prevLayer, Packet *  packet  )

inline

A constructor that creates the layer from an existing packet raw data

Parameters

[in]	data	A pointer to the raw data
[in]	dataLen	Size of the data in bytes
[in]	prevLayer	A pointer to the previous layer
[in]	packet	A pointer to the Packet instance where layer will be stored in

Member Function Documentation

getHeaderLen()

size_t pcpp::PacketTrailerLayer::getHeaderLen ( ) const

inlineoverridevirtual

Returns

trailer data length in bytes

Implements pcpp::Layer.

getOsiModelLayer()

OsiModelLayer pcpp::PacketTrailerLayer::getOsiModelLayer ( ) const

inlineoverridevirtual

Returns

The OSI Model layer this protocol belongs to

Implements pcpp::Layer.

getTrailerData()

uint8_t* pcpp::PacketTrailerLayer::getTrailerData ( ) const

inline

Get a pointer to the trailer data

Returns

A pointer to the trailer data

getTrailerDataAsHexString()

std::string pcpp::PacketTrailerLayer::getTrailerDataAsHexString

(

)

const

Returns

Trailer data as hex string

getTrailerLen()

size_t pcpp::PacketTrailerLayer::getTrailerLen ( ) const

inline

Get the trailer data length

Returns

The trailer data length in bytes

toString()

std::string pcpp::PacketTrailerLayer::toString ( ) const

overridevirtual

Returns

A string representation of the layer most important data (should look like the layer description in Wireshark)

Implements pcpp::Layer.