TelnetLayer.h

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#ifndef PACKETPP_TELNET_LAYER
#define PACKETPP_TELNET_LAYER

#include "Layer.h"


namespace pcpp
{

class TelnetLayer : public Layer
{
  private:
    // Position iterator for next command
    size_t lastPositionOffset;

    // Checks if position is a data field
    bool isDataField(uint8_t *pos) const;
    // Checks if position is a command field
    bool isCommandField(uint8_t *pos) const;
    // Returns distance to next IAC
    size_t distanceToNextIAC(uint8_t *startPos, size_t maxLength);
    // Returns length of provided field
    size_t getFieldLen(uint8_t *startPos, size_t maxLength);
    // Get position of next data field
    uint8_t *getNextDataField(uint8_t *pos, size_t len);
    // Get position of next command field
    uint8_t *getNextCommandField(uint8_t *pos, size_t len);
    // Get options of provided field
    int16_t getSubCommand(uint8_t *pos, size_t len);
    // Get data of provided field
    uint8_t *getCommandData(uint8_t *pos, size_t &slen);

  public:
    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
    };

    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
    };

    TelnetLayer(uint8_t *data, size_t dataLen, Layer *prevLayer, Packet *packet) : Layer(data, dataLen, prevLayer, packet)
    {
        m_Protocol = Telnet;
        lastPositionOffset = SIZE_MAX;
    };

    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);

    static std::string getTelnetCommandAsString(TelnetCommand val);

    static std::string getTelnetOptionAsString(TelnetOption val);

    static bool isTelnetPort(uint16_t port) { return port == 23; }

    static bool isDataValid(const uint8_t *data, size_t dataSize) { return data && dataSize; }

    // overridden methods

    void parseNextLayer() {}

    size_t getHeaderLen() const { return m_DataLen; }

    void computeCalculateFields() {}

    OsiModelLayer getOsiModelLayer() const { return OsiModelApplicationLayer; }

    std::string toString() const;
};

} // namespace pcpp

#endif /* PACKETPP_TELNET_LAYER */