#pragma once

#include "EthLayer.h"

#include "Layer.h"

/// @file

/// @namespace pcpp

/// @brief The main namespace for the PcapPlusPlus lib

namespace pcpp

{

  /// @struct tpkthdr

  /// Represents a TPKT protocol header

#pragma pack(push, 1)

  struct tpkthdr

  {

    /// message version

    uint8_t version;

    /// message reserved

    uint8_t reserved;

    /// message length

    uint16_t length;

  };

#pragma pack(pop)

  static_assert(sizeof(tpkthdr) == 4, "tpkthdr size is not 4 bytes");

  /// @class TpktLayer

  /// Represents a TPKT (Transport Service on top of the TCP) protocol layer

  class TpktLayer : public Layer

  {

  public:

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

    /// @param[in] data A pointer to the raw data (will be casted to @ref tpkthdr)

    /// @param[in] dataLen Size of the data in bytes

    /// @param[in] prevLayer A pointer to the previous layer

    /// @param[in] packet A pointer to the Packet instance where layer will be stored in

    TpktLayer(uint8_t* data, size_t dataLen, Layer* prevLayer, Packet* packet)

        : Layer(data, dataLen, prevLayer, packet, TPKT)

    {}

    /// A constructor that allocates a new TPKT header

    /// @param[in] version Protocol version number

    /// @param[in] length Packet length

    TpktLayer(uint8_t version, uint16_t length);

    ~TpktLayer() override = default;

    /// @return TPKT reserved

    uint8_t getReserved() const;

    /// @return TPKT version

    uint8_t getVersion() const;

    /// @return TPKT length

    uint16_t getLength() const;

    /// Set the value of the version

    /// @param[in] version The value of the version

    void setVersion(uint8_t version) const;

    /// Set the value of the length

    /// @param[in] length The value of the length

    void setLength(uint16_t length) const;

    /// @return Size of @ref tpkthdr

    size_t getHeaderLen() const override

    {

      return sizeof(tpkthdr);

    }

    /// Does nothing for this layer

    void computeCalculateFields() override

    {}

    /// Currently parses the rest of the packet as a COTP protocol or generic payload (PayloadLayer)

    void parseNextLayer() override;

    /// A static method that checks whether a source or dest port match those associated with the TPKT protocol

    /// @param[in] portSrc Source port number to check

    /// @param[in] portDst Dest port number to check

    /// @return True if the source or dest port match those associated with the TPKT protocol

    static bool isTpktPort(uint16_t portSrc, uint16_t portDst)

    {

      return portSrc == 102 || portDst == 102;

    }

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

    /// @param[in] data A byte array

    /// @param[in] dataSize The byte array size (in bytes)

    /// @return True if the data size is greater or equal than the size of tpkthdr

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

    {

      return canReinterpretAs<tpkthdr>(data, dataSize);

    }

    std::string toString() const override;

    OsiModelLayer getOsiModelLayer() const override

    {

      return OsiModelTransportLayer;

    }

  private:

    /// Get a pointer to the TPKT header. Data can be retrieved through the

    /// other methods of this layer. Notice the return value points directly to the data, so every change will

    /// change the actual packet data

    /// @return A pointer to the @ref tpkthdr

    tpkthdr* getTpktHeader() const

    {

      return reinterpret_cast<tpkthdr*>(m_Data);

    }

  };

}  // namespace pcpp