pcpp::GREv1Layer Class Reference

#include <GreLayer.h>

Inheritance diagram for pcpp::GREv1Layer:

Public Member Functions
	GREv1Layer (uint8_t *data, size_t dataLen, Layer *prevLayer, Packet *packet)
	GREv1Layer (uint16_t callID)
gre1_header *	getGreHeader () const
bool	getAcknowledgmentNum (uint32_t &ackNum) const
bool	setAcknowledgmentNum (uint32_t ackNum)
bool	unsetAcknowledgmentNum ()
void	computeCalculateFields () override
std::string	toString () const override
Public Member Functions inherited from pcpp::GreLayer
bool	getSequenceNumber (uint32_t &seqNumber) const
bool	setSequenceNumber (uint32_t seqNumber)
bool	unsetSequenceNumber ()
void	parseNextLayer () override
size_t	getHeaderLen () 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

Static Public Member Functions
static bool	isDataValid (const uint8_t *data, size_t dataLen)
Static Public Member Functions inherited from pcpp::GreLayer
static ProtocolType	getGREVersion (uint8_t *greData, size_t greDataLen)

Detailed Description

Represents a GRE version 1 protocol

Constructor & Destructor Documentation

GREv1Layer() [1/2]

pcpp::GREv1Layer::GREv1Layer ( 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

GREv1Layer() [2/2]

pcpp::GREv1Layer::GREv1Layer ( uint16_t  callID )

explicit

A constructor that creates a new GREv1 header and allocates the data

Parameters

[in]

callID

The call ID to set

Member Function Documentation

computeCalculateFields()

void pcpp::GREv1Layer::computeCalculateFields ( )

overridevirtual

Calculate the following fields:

• gre1_header::payloadLength
• gre_basic_header::protocol

Implements pcpp::Layer.

getAcknowledgmentNum()

bool pcpp::GREv1Layer::getAcknowledgmentNum

(

uint32_t &

ackNum

)

const

Get acknowledgment (ack) number value if field exists in layer

Parameters

[out]

ackNum

The returned ack number value if exists in layer. Else remain unchanged

Returns

True if ack number field exists in layer. In this case ackNum will be filled with the value. Or false if ack number field doesn't exist in layer

getGreHeader()

gre1_header* pcpp::GREv1Layer::getGreHeader ( ) const

inline

Get a pointer to the basic GREv1 header containing all non-optional fields. Notice this points directly to the data, so every change will change the actual packet data. Also please notice that changing the set bits (gre_basic_header::strictSourceRouteBit, gre_basic_header::sequenceNumBit, gre_basic_header::keyBit, gre_basic_header::routingBit, gre_basic_header::checksumBit, gre_basic_header::ackSequenceNumBit) without using the proper set or unset methods (such as setAcknowledgmentNum(), unsetSequenceNumber(), etc.) may result to wrong calculation of header length or illegal GREv1 packet and to some really weird bugs. Please avoid doing so

Returns

A pointer to the gre1_header

isDataValid()

static bool pcpp::GREv1Layer::isDataValid ( const uint8_t *  data, size_t  dataLen  )

inlinestatic

A static method that validates the input data

Parameters

[in]	data	The pointer to the beginning of a byte stream of an GREv1 layer
[in]	dataLen	The length of the byte stream

Returns

True if the data is valid and can represent an GREv1 layer

setAcknowledgmentNum()

bool pcpp::GREv1Layer::setAcknowledgmentNum

(

uint32_t

ackNum

)

Set acknowledgment (ack) number value. If field already exists (gre_basic_header::ackSequenceNumBit is set) then only the new value is set. If field doesn't exist it will be added to the layer, gre_basic_header::ackSequenceNumBit will be set and the new value will be set

Parameters

[in]

ackNum

The ack number value to set

Returns

True if managed to set the value successfully, or false otherwise (if couldn't extend the layer)

toString()

std::string pcpp::GREv1Layer::toString ( ) const

overridevirtual

Returns

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

Implements pcpp::Layer.

unsetAcknowledgmentNum()

bool pcpp::GREv1Layer::unsetAcknowledgmentNum

(

)

Unset acknowledgment (ack) number and remove it from the layer

Returns

True if managed to unset successfully or false (and error log) if ack number wasn't set in the first place or if didn't manage to remove it from the layer