pcpp::TelnetLayer Class Reference

Class for representing the Telnet Layer. More...

#include <TelnetLayer.h>

Inheritance diagram for pcpp::TelnetLayer:

Public Types
enum class	TelnetCommand : int {   TelnetCommandEndOfPacket = -1 , EndOfFile = 236 , Suspend , Abort ,   EndOfRecordCommand , SubnegotiationEnd , NoOperation , DataMark ,   Break , InterruptProcess , AbortOutput , AreYouThere ,   EraseCharacter , EraseLine , GoAhead , Subnegotiation ,   WillPerform , WontPerform , DoPerform , DontPerform ,   InterpretAsCommand }
	Telnet Command Indicator. More...
enum class	TelnetOption : int {   TelnetOptionNoOption = -1 , TransmitBinary = 0 , Echo , Reconnection ,   SuppressGoAhead , ApproxMsgSizeNegotiation , Status , TimingMark ,   RemoteControlledTransAndEcho , OutputLineWidth , OutputPageSize , OutputCarriageReturnDisposition ,   OutputHorizontalTabStops , OutputHorizontalTabDisposition , OutputFormfeedDisposition , OutputVerticalTabStops ,   OutputVerticalTabDisposition , OutputLinefeedDisposition , ExtendedASCII , Logout ,   ByteMacro , DataEntryTerminal , SUPDUP , SUPDUPOutput ,   SendLocation , TerminalType , EndOfRecordOption , TACACSUserIdentification ,   OutputMarking , TerminalLocationNumber , Telnet3270Regime , X3Pad ,   NegotiateAboutWindowSize , TerminalSpeed , RemoteFlowControl , Linemode ,   XDisplayLocation , EnvironmentOption , AuthenticationOption , EncryptionOption ,   NewEnvironmentOption , TN3270E , XAuth , Charset ,   TelnetRemoteSerialPort , ComPortControlOption , TelnetSuppressLocalEcho , TelnetStartTLS ,   Kermit , SendURL , ForwardX , TelOptPragmaLogon = 138 ,   TelOptSSPILogon , TelOptPragmaHeartbeat , ExtendedOptions = 255 }
	Telnet Options. More...

Public Member Functions
	TelnetLayer (uint8_t *data, size_t dataLen, Layer *prevLayer, Packet *packet)
std::string	getDataAsString (bool removeEscapeCharacters=true)
size_t	getTotalNumberOfCommands ()
size_t	getNumberOfCommands (TelnetCommand command)
TelnetCommand	getFirstCommand ()
TelnetCommand	getNextCommand ()
TelnetOption	getOption ()
TelnetOption	getOption (TelnetCommand command)
uint8_t *	getOptionData (size_t &length)
uint8_t *	getOptionData (TelnetCommand command, size_t &length)
void	parseNextLayer () override
	Parses the next layer. Telnet is the always last so does nothing for this layer.
size_t	getHeaderLen () const override
void	computeCalculateFields () override
	Does nothing for this layer.
OsiModelLayer	getOsiModelLayer () const override
std::string	toString () 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 std::string	getTelnetCommandAsString (TelnetCommand val)
static std::string	getTelnetOptionAsString (TelnetOption val)
static bool	isTelnetPort (uint16_t port)
static bool	isDataValid (const uint8_t *data, size_t dataSize)

Additional Inherited Members
Protected Member Functions inherited from pcpp::Layer
template<typename T , typename... Args>
Layer *	constructNextLayer (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, Packet *packet, Args &&... extraArgs)
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

Class for representing the Telnet Layer.

Member Enumeration Documentation

TelnetCommand

enum pcpp::TelnetLayer::TelnetCommand : int

strong

Telnet Command Indicator.

Enumerator
TelnetCommandEndOfPacket	Indicator to parser reached end of packet.
EndOfFile	End of file.
Suspend	Suspend current process.
Abort	Abort Process.
EndOfRecordCommand	End of Record.
SubnegotiationEnd	Marks the end of a Telnet option subnegotiation, used with the SB code to specify more specific option parameters.
NoOperation	Null command; does nothing.
DataMark	Used to mark the end of a sequence of data that the recipient should scan for urgent Telnet commands.
Break	Represents the pressing of the “break” or “attention” key on the terminal.
InterruptProcess	Tells the recipient to interrupt, abort, suspend or terminate the process currently in use.
AbortOutput	Instructs the remote host to continue running the current process, but discard all remaining output from it. This may be needed if a program starts to send unexpectedly large amounts of data to the user.
AreYouThere	May be used to check that the remote host is still “alive”. When this character is sent the remote host returns some type of output to indicate that it is still functioning.
EraseCharacter	Instructs the recipient to delete the last undeleted character from the data stream. Used to “undo” the sending of a character.
EraseLine	Tells the recipient to delete all characters from the data stream back to (but not including) the last end of line (CR+LF) sequence.
GoAhead	Used in Telnet half-duplex mode to signal the other device that it may transmit.
Subnegotiation	Marks the beginning of a Telnet option subnegotiation, used when an option requires the client and server to exchange parameters.
WillPerform	Indicates that the device sending this code is willing to perform or continue performing a particular option.
WontPerform	Indicates that the device sending this code is either not willing to perform a particular option, or is now refusing to continue to perform it.
DoPerform	Requests that the other device perform a particular option or confirms the expectation that the other device will perform that option.
DontPerform	Specifies that the other party not perform an option, or confirms a device’s expectation that the other party not perform an option.
InterpretAsCommand	Precedes command values 240 through 254 as described above. A pair of IAC bytes in a row represents the data value 255.

TelnetOption

enum pcpp::TelnetLayer::TelnetOption : int

strong

Telnet Options.

Enumerator
TelnetOptionNoOption	Internal return for no option detected.
TransmitBinary	Binary Transmission RFC856 https://www.iana.org/go/rfc856.
Echo	Echo RFC857 https://www.iana.org/go/rfc857.
Reconnection	Reconnection.
SuppressGoAhead	Suppress Go Ahead RFC858 https://www.iana.org/go/rfc858.
ApproxMsgSizeNegotiation	Negotiate approximate message size.
Status	Status RFC859 https://www.iana.org/go/rfc859.
TimingMark	Timing Mark RFC860 https://www.iana.org/go/rfc860.
RemoteControlledTransAndEcho	RCTE, Remote Controlled Transmission and Echo RFC726 https://www.iana.org/go/rfc726.
OutputLineWidth	Output Line Width.
OutputPageSize	Output Page Size.
OutputCarriageReturnDisposition	NAOCRD, Negotiate About Output Carriage-Return Disposition RFC652 https://www.iana.org/go/rfc652.
OutputHorizontalTabStops	NAOHTS, Negotiate About Output Horizontal Tabstops RFC653 https://www.iana.org/go/rfc653.
OutputHorizontalTabDisposition	NAOHTD, Negotiate About Output Horizontal Tab Disposition RFC654 https://www.iana.org/go/rfc654.
OutputFormfeedDisposition	NAOFFD, Negotiate About Output Formfeed Disposition RFC655 https://www.iana.org/go/rfc655.
OutputVerticalTabStops	NAOVTS, Negotiate About Vertical Tabstops RFC656 https://www.iana.org/go/rfc656.
OutputVerticalTabDisposition	NAOVTD, Negotiate About Output Vertcial Tab Disposition RFC657 https://www.iana.org/go/rfc657.
OutputLinefeedDisposition	NAOLFD, Negotiate About Output Linefeed Disposition RFC658 https://www.iana.org/go/rfc658.
ExtendedASCII	Extended ASCII RFC698 https://www.iana.org/go/rfc698.
Logout	Logout RFC727 https://www.iana.org/go/rfc727.
ByteMacro	BM, Byte Macro RFC735 https://www.iana.org/go/rfc735.
DataEntryTerminal	Data Entry Terminal RFC1043 - RFC732 https://www.iana.org/go/rfc1043 https://www.iana.org/go/rfc732.
SUPDUP	SUPDUP RFC736 - RFC734 https://www.iana.org/go/rfc736 https://www.iana.org/go/rfc734.
SUPDUPOutput	SUPDUP Output RFC749 https://www.iana.org/go/rfc749.
SendLocation	Send Location RFC779 https://www.iana.org/go/rfc779.
TerminalType	Terminal Type RFC1091 https://www.iana.org/go/rfc1091.
EndOfRecordOption	End of record RFC885 https://www.iana.org/go/rfc885.
TACACSUserIdentification	TUID, TACACS User Identification RFC927 https://www.iana.org/go/rfc927.
OutputMarking	OUTMRK, Output Marking RFC933 https://www.iana.org/go/rfc933.
TerminalLocationNumber	TTYLOC, Terminal Location Number RFC946 https://www.iana.org/go/rfc946.
Telnet3270Regime	Telnet 3270 Regime RFC1041 https://www.iana.org/go/rfc1041.
X3Pad	X.3 PAD RFC1053 https://www.iana.org/go/rfc1053.
NegotiateAboutWindowSize	NAWS, Negotiate About Window Size RFC1073 https://www.iana.org/go/rfc1073.
TerminalSpeed	Terminal Speed RFC1079 https://www.iana.org/go/rfc1079.
RemoteFlowControl	Remote Flow Control RFC1372 https://www.iana.org/go/rfc1372.
Linemode	Line Mode RFC1184 https://www.iana.org/go/rfc1184.
XDisplayLocation	X Display Location RFC1096 https://www.iana.org/go/rfc1096.
EnvironmentOption	Environment Option RFC1408 https://www.iana.org/go/rfc1408.
AuthenticationOption	Authentication Option RFC2941 https://www.iana.org/go/rfc2941.
EncryptionOption	Encryption Option RFC2946 https://www.iana.org/go/rfc2946.
NewEnvironmentOption	New Environment Option RFC1572 https://www.iana.org/go/rfc1572.
TN3270E	TN3270E RFC2355 https://www.iana.org/go/rfc2355.
XAuth	X Server Authentication.
Charset	Charset RFC2066 https://www.iana.org/go/rfc2066.
TelnetRemoteSerialPort	RSP, Telnet Remote Serial Port.
ComPortControlOption	Com Port Control Option RFC2217 https://www.iana.org/go/rfc2217.
TelnetSuppressLocalEcho	Telnet Suppress Local Echo.
TelnetStartTLS	Telnet Start TLS.
Kermit	Kermit RFC2840 https://www.iana.org/go/rfc2840.
SendURL	Send URL.
ForwardX	Forward X Server.
TelOptPragmaLogon	Telnet Option Pragma Logon.
TelOptSSPILogon	Telnet Option SSPI Logon.
TelOptPragmaHeartbeat	Telnet Option Pragma Heartbeat.
ExtendedOptions	Extended option list.

Constructor & Destructor Documentation

TelnetLayer()

pcpp::TelnetLayer::TelnetLayer ( 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

getDataAsString()

std::string pcpp::TelnetLayer::getDataAsString

(

bool

removeEscapeCharacters = true

)

Get the Telnet data as readable string

Parameters

[in]

removeEscapeCharacters

Whether non-alphanumerical characters should be removed or not

Returns

Full payload as readable string, empty if Telnet packet contains control commands/options.

getFirstCommand()

TelnetCommand pcpp::TelnetLayer::getFirstCommand

(

)

Returns the first command of packet

Returns

TelnetCommand First detected command value, TelnetCommandEndOfPacket if there is no command field

getHeaderLen()

size_t pcpp::TelnetLayer::getHeaderLen ( ) const

inlineoverridevirtual

Returns

Get the size of the layer

Implements pcpp::Layer.

getNextCommand()

TelnetCommand pcpp::TelnetLayer::getNextCommand

(

)

Returns the next command of packet. Uses an internal iterator. The iterator resets when reached end of packet.

Returns

TelnetCommand Detected command value, TelnetCommandEndOfPacket if reached the end of packet.

getNumberOfCommands()

size_t pcpp::TelnetLayer::getNumberOfCommands

(

TelnetCommand

command

)

Returns the number of occurrences of provided command

Parameters

[in]

command

Telnet command to count

Returns

size_t Number of occurrences of command

getOption() [1/2]

TelnetOption pcpp::TelnetLayer::getOption

(

)

Returns the option of current command. Uses an internal iterator. Iterator can be moved with getNextCommand

Returns

TelnetOption Option of current command

getOption() [2/2]

TelnetOption pcpp::TelnetLayer::getOption

(

TelnetCommand

command

)

Returns the option of provided command. It will return option of first occurrence of the command

Parameters

[in]

command

Telnet command to search

Returns

TelnetOption Option of the command. Returns TelnetOptionNoOption if the provided command not found.

getOptionData() [1/2]

uint8_t* pcpp::TelnetLayer::getOptionData

(

size_t &

length

)

Returns the data of current command. Uses an internal iterator. Iterator can be moved with getNextCommand

Parameters

[out]

length

Length of the data of current command

Returns

uint8_t* Pointer to the data of current command. nullptr if there is no data for this command.

getOptionData() [2/2]

uint8_t* pcpp::TelnetLayer::getOptionData	(	TelnetCommand	command,
		size_t &	length
	)

Returns the data of provided command. It will return data of first occurrence of the command

Parameters

[in]	command	Telnet command to search
[out]	length	Length of the data of current command

Returns

uint8_t* Pointer to the data of current command. nullptr if there is no data for this command or if can't find the command.

getOsiModelLayer()

OsiModelLayer pcpp::TelnetLayer::getOsiModelLayer ( ) const

inlineoverridevirtual

Returns

The OSI layer level of Telnet (Application Layer).

Implements pcpp::Layer.

getTelnetCommandAsString()

static std::string pcpp::TelnetLayer::getTelnetCommandAsString ( TelnetCommand  val )

static

Convert the Telnet Command to readable string

Parameters

[in]

val

Value of the command

Returns

The Telnet Command as readable string

getTelnetOptionAsString()

static std::string pcpp::TelnetLayer::getTelnetOptionAsString ( TelnetOption  val )

static

Convert the Telnet option to readable string

Parameters

[in]

val

Value of the option

Returns

The Telnet Option as readable string

getTotalNumberOfCommands()

size_t pcpp::TelnetLayer::getTotalNumberOfCommands

(

)

Get the total number of detected Telnet commands

Returns

size_t The number of Telnet commands

isDataValid()

static bool pcpp::TelnetLayer::isDataValid ( const uint8_t *  data, size_t  dataSize  )

inlinestatic

A static method that takes a byte array and detects whether it is a Telnet message

Parameters

[in]	data	A byte array
[in]	dataSize	The byte array size (in bytes)

Returns

True if the data is identified as Telnet message

isTelnetPort()

static bool pcpp::TelnetLayer::isTelnetPort ( uint16_t  port )

inlinestatic

A static method that checks whether the port is considered as Telnet

Parameters

[in]

port

The port number to be checked

toString()

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

overridevirtual

Returns

Returns the protocol info as readable string

Implements pcpp::Layer.