#pragma once

#include "DeprecationUtils.h"

#include "Layer.h"

#include "TLVData.h"

#include <string.h>

#define PCPP_DEPRECATED_TCP_OPTION_TYPE                                                                                \

  PCPP_DEPRECATED("enum TcpOptionType is deprecated; Use enum class TcpOptionEnumType instead")

/// @file

/// @namespace pcpp

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

namespace pcpp

{

  /// @struct tcphdr

  /// Represents an TCP protocol header

#pragma pack(push, 1)

  struct tcphdr

  {

    /// Source TCP port

    uint16_t portSrc;

    /// Destination TCP port

    uint16_t portDst;

    /// Sequence number

    uint32_t sequenceNumber;

    /// Acknowledgment number

    uint32_t ackNumber;

#if (BYTE_ORDER == LITTLE_ENDIAN)

    /// Accurate ECN flag

    uint16_t accurateEcnFlag : 1;

    /// Reserved bits

    uint16_t reserved : 3;

    /// Specifies the size of the TCP header in 32-bit words

    uint16_t dataOffset : 4;

    /// FIN flag

    uint16_t finFlag : 1;

    /// SYN flag

    uint16_t synFlag : 1;

    /// RST flag

    uint16_t rstFlag : 1;

    /// PSH flag

    uint16_t pshFlag : 1;

    /// ACK flag

    uint16_t ackFlag : 1;

    /// URG flag

    uint16_t urgFlag : 1;

    /// ECE flag

    uint16_t eceFlag : 1;

    /// CWR flag

    uint16_t cwrFlag : 1;

#elif (BYTE_ORDER == BIG_ENDIAN)

    /// Specifies the size of the TCP header in 32-bit words

    uint16_t dataOffset : 4;

    /// Reserved

    uint16_t reserved : 3;

    /// Accurate ECN flag

    uint16_t accurateEcnFlag : 1;

    /// CWR flag

    uint16_t cwrFlag : 1;

    /// ECE flag

    uint16_t eceFlag : 1;

    /// URG flag

    uint16_t urgFlag : 1;

    /// ACK flag

    uint16_t ackFlag : 1;

    /// PSH flag

    uint16_t pshFlag : 1;

    /// RST flag

    uint16_t rstFlag : 1;

    /// SYN flag

    uint16_t synFlag : 1;

    /// FIN flag

    uint16_t finFlag : 1;

#else

# error "Endian is not LE nor BE..."

#endif

    /// The size of the receive window, which specifies the number of window size units (by default, bytes)

    uint16_t windowSize;

    /// The 16-bit checksum field is used for error-checking of the header and data

    uint16_t headerChecksum;

    /// If the URG flag (@ref tcphdr#urgFlag) is set, then this 16-bit field is an offset from the sequence number

    /// indicating the last urgent data byte

    uint16_t urgentPointer;

  };

#pragma pack(pop)

  static_assert(sizeof(tcphdr) == 20, "tcphdr size is not 20 bytes");

  /// TCP options types

  enum TcpOptionType : uint8_t

  {

    /// Padding

    PCPP_TCPOPT_NOP = 1,

    /// End of options

    PCPP_TCPOPT_EOL = 0,

    /// Segment size negotiating

    TCPOPT_MSS = 2,

    /// Window scaling

    PCPP_TCPOPT_WINDOW = 3,

    /// SACK Permitted

    TCPOPT_SACK_PERM = 4,

    /// SACK Block

    PCPP_TCPOPT_SACK = 5,

    /// Echo (obsoleted by option TcpOptionType::PCPP_TCPOPT_TIMESTAMP)

    TCPOPT_ECHO = 6,

    /// Echo Reply (obsoleted by option TcpOptionType::PCPP_TCPOPT_TIMESTAMP)

    TCPOPT_ECHOREPLY = 7,

    /// TCP Timestamps

    PCPP_TCPOPT_TIMESTAMP = 8,

    /// CC (obsolete)

    TCPOPT_CC = 11,

    /// CC.NEW (obsolete)

    TCPOPT_CCNEW = 12,

    /// CC.ECHO(obsolete)

    TCPOPT_CCECHO = 13,

    /// MD5 Signature Option

    TCPOPT_MD5 = 19,

    /// Multipath TCP

    TCPOPT_MPTCP = 0x1e,

    /// SCPS Capabilities

    TCPOPT_SCPS = 20,

    /// SCPS SNACK

    TCPOPT_SNACK = 21,

    /// SCPS Record Boundary

    TCPOPT_RECBOUND = 22,

    /// SCPS Corruption Experienced

    TCPOPT_CORREXP = 23,

    /// Quick-Start Response

    TCPOPT_QS = 27,

    /// User Timeout Option (also, other known unauthorized use)

    TCPOPT_USER_TO = 28,

    /// RFC3692-style Experiment 1 (also improperly used for shipping products)

    TCPOPT_EXP_FD = 0xfd,

    /// RFC3692-style Experiment 2 (also improperly used for shipping products)

    TCPOPT_EXP_FE = 0xfe,

    /// Riverbed probe option, non IANA registered option number

    TCPOPT_RVBD_PROBE = 76,

    /// Riverbed transparency option, non IANA registered option number

    TCPOPT_RVBD_TRPY = 78,

    /// Unknown option

    TCPOPT_Unknown = 255

  };

  /// TCP options types

  enum class TcpOptionEnumType : uint8_t

  {

    /// Padding

    Nop = 1,

    /// End of options

    Eol = 0,

    /// Segment size negotiating

    Mss = 2,

    /// Window scaling

    Window = 3,

    /// SACK Permitted

    SackPerm = 4,

    /// SACK Block

    Sack = 5,

    /// Echo (obsoleted by option TcpOptionEnumType::Timestamp)

    Echo = 6,

    /// Echo Reply (obsoleted by option TcpOptionEnumType::Timestamp)

    EchoReply = 7,

    /// TCP Timestamps

    Timestamp = 8,

    /// CC (obsolete)

    Cc = 11,

    /// CC.NEW (obsolete)

    CcNew = 12,

    /// CC.ECHO(obsolete)

    CcEcho = 13,

    /// MD5 Signature Option

    Md5 = 19,

    /// Multipath TCP

    MpTcp = 0x1e,

    /// SCPS Capabilities

    Scps = 20,

    /// SCPS SNACK

    Snack = 21,

    /// SCPS Record Boundary

    RecBound = 22,

    /// SCPS Corruption Experienced

    CorrExp = 23,

    /// Quick-Start Response

    Qs = 27,

    /// User Timeout Option (also, other known unauthorized use)

    UserTo = 28,

    /// RFC3692-style Experiment 1 (also improperly used for shipping products)

    ExpFd = 0xfd,

    /// RFC3692-style Experiment 2 (also improperly used for shipping products)

    ExpFe = 0xfe,

    /// Riverbed probe option, non IANA registered option number

    RvbdProbe = 76,

    /// Riverbed transparency option, non IANA registered option number

    RvbdTrpy = 78,

    /// Unknown option

    Unknown = 255

  };

  // TCP option lengths

  /// pcpp::TcpOptionEnumType::Nop length

#define PCPP_TCPOLEN_NOP 1

  /// pcpp::TcpOptionEnumType::Eol length

#define PCPP_TCPOLEN_EOL 1

  /// pcpp::TcpOptionEnumType::Mss length

#define PCPP_TCPOLEN_MSS 4

  /// pcpp::TcpOptionEnumType::Window length

#define PCPP_TCPOLEN_WINDOW 3

  /// pcpp::TcpOptionEnumType::SackPerm length

#define PCPP_TCPOLEN_SACK_PERM 2

  /// pcpp::TcpOptionEnumType::Sack length

#define PCPP_TCPOLEN_SACK_MIN 2

  /// pcpp::TcpOptionEnumType::Echo length

#define PCPP_TCPOLEN_ECHO 6

  /// pcpp::TcpOptionEnumType::EchoReply length

#define PCPP_TCPOLEN_ECHOREPLY 6

  /// pcpp::TcpOptionEnumType::Timestamp length

#define PCPP_TCPOLEN_TIMESTAMP 10

  /// pcpp::TcpOptionEnumType::Cc length

#define PCPP_TCPOLEN_CC 6

  /// pcpp::TcpOptionEnumType::CcNew length

#define PCPP_TCPOLEN_CCNEW 6

  /// pcpp::TcpOptionEnumType::CcEcho length

#define PCPP_TCPOLEN_CCECHO 6

  /// pcpp::TcpOptionEnumType::Md5 length

#define PCPP_TCPOLEN_MD5 18

  /// pcpp::TcpOptionEnumType::MpTcp length

#define PCPP_TCPOLEN_MPTCP_MIN 8

  /// pcpp::TcpOptionEnumType::Scps length

#define PCPP_TCPOLEN_SCPS 4

  /// pcpp::TcpOptionEnumType::Snack length

#define PCPP_TCPOLEN_SNACK 6

  /// pcpp::TcpOptionEnumType::RecBound length

#define PCPP_TCPOLEN_RECBOUND 2

  /// pcpp::TcpOptionEnumType::CorrExp length

#define PCPP_TCPOLEN_CORREXP 2

  /// pcpp::TcpOptionEnumType::Qs length

#define PCPP_TCPOLEN_QS 8

  /// pcpp::TcpOptionEnumType::UserTo length

#define PCPP_TCPOLEN_USER_TO 4

  /// pcpp::TcpOptionEnumType::RvbdProbe length

#define PCPP_TCPOLEN_RVBD_PROBE_MIN 3

  /// pcpp::TcpOptionEnumType::RvbdTrpy length

#define PCPP_TCPOLEN_RVBD_TRPY_MIN 16

  /// pcpp::TcpOptionEnumType::ExpFd and pcpp::TcpOptionEnumType::ExpFe length

#define PCPP_TCPOLEN_EXP_MIN 2

  /// @class TcpOption

  /// A wrapper class for TCP options. This class does not create or modify TCP option records, but rather

  /// serves as a wrapper and provides useful methods for retrieving data from them

  class TcpOption : public TLVRecord<uint8_t, uint8_t>

  {

  public:

    /// A c'tor for this class that gets a pointer to the option raw data (byte array)

    /// @param[in] optionRawData A pointer to the TCP option raw data

    explicit TcpOption(uint8_t* optionRawData) : TLVRecord(optionRawData)

    {}

    /// A d'tor for this class, currently does nothing

    ~TcpOption() override = default;

    /// @deprecated This method is deprecated, please use getTcpOptionEnumType()

    PCPP_DEPRECATED("Use getTcpOptionEnumType instead")

    TcpOptionType getTcpOptionType() const

    {

      return getTcpOptionType(m_Data);

    }

    /// @return TCP option type casted as pcpp::TcpOptionEnumType enum. If the data is null a value

    /// of TcpOptionEnumType::Unknown is returned

    TcpOptionEnumType getTcpOptionEnumType() const

    {

      return getTcpOptionEnumType(m_Data);

    }

    /// Check if a pointer can be assigned to the TLV record data

    /// @param[in] recordRawData A pointer to the TLV record raw data

    /// @param[in] tlvDataLen The size of the TLV record raw data

    /// @return True if data is valid and can be assigned

    static bool canAssign(const uint8_t* recordRawData, size_t tlvDataLen)

    {

      const auto* data = reinterpret_cast<const TLVRawData*>(recordRawData);

      if (data == nullptr)

        return false;

      if (tlvDataLen < sizeof(TLVRawData::recordType))

        return false;

      const auto recordType = getTcpOptionEnumType(data);

      if (recordType == TcpOptionEnumType::Nop || recordType == TcpOptionEnumType::Eol)

        return true;

      return TLVRecord<uint8_t, uint8_t>::canAssign(recordRawData, tlvDataLen);

    }

    // implement abstract methods

    size_t getTotalSize() const override

    {

      if (m_Data == nullptr)

        return 0;

      const auto recordType = getTcpOptionEnumType(m_Data);

      if (recordType == TcpOptionEnumType::Nop || recordType == TcpOptionEnumType::Eol)

        return sizeof(uint8_t);

      return static_cast<size_t>(m_Data->recordLen);

    }

    size_t getDataSize() const override

    {

      if (m_Data == nullptr)

        return 0;

      const auto recordType = getTcpOptionEnumType(m_Data);

      if (recordType == TcpOptionEnumType::Nop || recordType == TcpOptionEnumType::Eol)

        return 0;

      return static_cast<size_t>(m_Data->recordLen) - (2 * sizeof(uint8_t));

    }

  private:

    static TcpOptionType getTcpOptionType(const TLVRawData* optionRawData)

    {

      if (optionRawData == nullptr)

        return TcpOptionType::TCPOPT_Unknown;

      return static_cast<TcpOptionType>(optionRawData->recordType);

    }

    static TcpOptionEnumType getTcpOptionEnumType(const TLVRawData* optionRawData)

    {

      if (optionRawData == nullptr)

        return TcpOptionEnumType::Unknown;

      return static_cast<TcpOptionEnumType>(optionRawData->recordType);

    }

  };

  /// @class TcpOptionBuilder

  /// A class for building TCP option records. This builder receives the TCP option parameters in its c'tor,

  /// builds the TCP option raw buffer and provides a build() method to get a TcpOption object out of it

  class TcpOptionBuilder : public TLVRecordBuilder

  {

  public:

    /// An enum to describe NOP and EOL TCP options. Used in one of this class's c'tors

    enum NopEolOptionTypes : uint8_t

    {

      /// NOP TCP option

      NOP,

      /// EOL TCP option

      EOL

    };

    /// An enum to describe NOP and EOL TCP options. Used in one of this class's c'tors

    enum class NopEolOptionEnumType : uint8_t

    {

      /// NOP TCP option

      Nop,

      /// EOL TCP option

      Eol

    };

    /// @deprecated This method is deprecated, please use constructor with TcpOptionEnumType

    PCPP_DEPRECATED_TCP_OPTION_TYPE

    TcpOptionBuilder(TcpOptionType optionType, const uint8_t* optionValue, uint8_t optionValueLen)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue, optionValueLen)

    {}

    /// A c'tor for building TCP options which their value is a byte array. The TcpOption object can be later

    /// retrieved by calling build()

    /// @param[in] optionType TCP option type

    /// @param[in] optionValue A buffer containing the option value. This buffer is read-only and isn't modified in

    /// any way.

    /// @param[in] optionValueLen Option value length in bytes

    TcpOptionBuilder(TcpOptionEnumType optionType, const uint8_t* optionValue, uint8_t optionValueLen)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue, optionValueLen)

    {}

    /// @deprecated This method is deprecated, please use constructor with TcpOptionEnumType

    PCPP_DEPRECATED_TCP_OPTION_TYPE

    TcpOptionBuilder(TcpOptionType optionType, uint8_t optionValue)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue)

    {}

    /// A c'tor for building TCP options which have a 1-byte value. The TcpOption object can be later retrieved

    /// by calling build()

    /// @param[in] optionType TCP option type

    /// @param[in] optionValue A 1-byte option value

    TcpOptionBuilder(TcpOptionEnumType optionType, uint8_t optionValue)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue)

    {}

    /// @deprecated This method is deprecated, please use constructor with TcpOptionEnumType

    PCPP_DEPRECATED_TCP_OPTION_TYPE

    TcpOptionBuilder(TcpOptionType optionType, uint16_t optionValue)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue)

    {}

    /// A c'tor for building TCP options which have a 2-byte value. The TcpOption object can be later retrieved

    /// by calling build()

    /// @param[in] optionType TCP option type

    /// @param[in] optionValue A 2-byte option value

    TcpOptionBuilder(TcpOptionEnumType optionType, uint16_t optionValue)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue)

    {}

    /// @deprecated This method is deprecated, please use constructor with TcpOptionEnumType

    PCPP_DEPRECATED_TCP_OPTION_TYPE

    TcpOptionBuilder(TcpOptionType optionType, uint32_t optionValue)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue)

    {}

    /// A c'tor for building TCP options which have a 4-byte value. The TcpOption object can be later retrieved

    /// by calling build()

    /// @param[in] optionType TCP option type

    /// @param[in] optionValue A 4-byte option value

    TcpOptionBuilder(TcpOptionEnumType optionType, uint32_t optionValue)

        : TLVRecordBuilder(static_cast<uint8_t>(optionType), optionValue)

    {}

    /// @deprecated This method is deprecated, please use constructor with NopEolOptionEnumType

    PCPP_DEPRECATED("enum NopEolOptionTypes is deprecated; Use enum class NopEolOptionEnumType instead")

    explicit TcpOptionBuilder(NopEolOptionTypes optionType);

    /// A c'tor for building TCP NOP and EOL options. These option types are special in that they contain only 1

    /// byte which is the TCP option type (NOP or EOL). The TcpOption object can be later retrieved by calling

    /// build()

    /// @param[in] optionType An enum value indicating which option type to build (NOP or EOL)

    explicit TcpOptionBuilder(NopEolOptionEnumType optionType);

    /// Build the TcpOption object out of the parameters defined in the c'tor

    /// @return The TcpOption object

    TcpOption build() const;

  };

  /// @class TcpLayer

  /// Represents a TCP (Transmission Control Protocol) protocol layer

  class TcpLayer : 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 tcphdr)

    /// @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

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

    /// A constructor that allocates a new TCP header with zero TCP options

    TcpLayer();

    /// A constructor that allocates a new TCP header with source port and destination port and zero TCP options

    /// @param[in] portSrc Source port

    /// @param[in] portDst Destination port

    TcpLayer(uint16_t portSrc, uint16_t portDst);

    ~TcpLayer() override = default;

    /// A copy constructor that copy the entire header from the other TcpLayer (including TCP options)

    TcpLayer(const TcpLayer& other);

    /// An assignment operator that first delete all data from current layer and then copy the entire header from

    /// the other TcpLayer (including TCP options)

    TcpLayer& operator=(const TcpLayer& other);

    /// Get a pointer to the TCP header. Notice this points directly to the data, so every change will change the

    /// actual packet data

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

    tcphdr* getTcpHeader() const

    {

      return reinterpret_cast<tcphdr*>(m_Data);

    }

    /// @return TCP source port

    uint16_t getSrcPort() const;

    /// @return TCP destination port

    uint16_t getDstPort() const;

    /// @deprecated This method is deprecated, please use getTcpOption(TcpOptionEnumType option)

    PCPP_DEPRECATED_TCP_OPTION_TYPE

    TcpOption getTcpOption(TcpOptionType option) const;

    /// Get a TCP option by type

    /// @param[in] option TCP option type to retrieve

    /// @return An TcpOption object that contains the first option that matches this type, or logical null

    /// (TcpOption#isNull() == true) if no such option found

    TcpOption getTcpOption(TcpOptionEnumType option) const;

    /// @return The first TCP option in the packet. If the current layer contains no options the returned value will

    /// contain a logical null (TcpOption#isNull() == true)

    TcpOption getFirstTcpOption() const;

    /// Get the TCP option that comes after a given option. If the given option was the last one, the

    /// returned value will contain a logical null (TcpOption#isNull() == true)

    /// @param[in] tcpOption A TCP option object that exists in the current layer

    /// @return A TcpOption object that contains the TCP option data that comes next, or logical null if the given

    /// TCP option: (1) was the last one; or (2) contains a logical null; or (3) doesn't belong to this packet

    TcpOption getNextTcpOption(TcpOption& tcpOption) const;

    /// @return The number of TCP options in this layer

    size_t getTcpOptionCount() const;

    /// Add a new TCP option at the end of the layer (after the last TCP option)

    /// @param[in] optionBuilder A TcpOptionBuilder object that contains the TCP option data to be added

    /// @return A TcpOption object that contains the newly added TCP option data or logical null

    /// (TcpOption#isNull() == true) if addition failed. In case of a failure a corresponding error message will be

    /// printed to log

    TcpOption addTcpOption(const TcpOptionBuilder& optionBuilder);

    /// @deprecated This method is deprecated, please use insertTcpOptionAfter(const TcpOptionBuilder&

    /// optionBuilder, TcpOptionEnumType prevOptionType = TcpOptionEnumType::Unknown)

    PCPP_DEPRECATED("Use insertTcpOptionAfter instead")

    TcpOption addTcpOptionAfter(const TcpOptionBuilder& optionBuilder,

                                TcpOptionType prevOptionType = TcpOptionType::TCPOPT_Unknown);

    /// Insert a new TCP option after an existing one

    /// @param[in] optionBuilder A TcpOptionBuilder object that contains the requested TCP option data to be

    /// inserted

    /// @param[in] prevOptionType The TCP option which the newly inserted option should come after. This is an

    /// optional parameter which gets a default value of TcpOptionType::Unknown if omitted, which means the new

    /// option will be inserted as the first option in the layer

    /// @return A TcpOption object containing the newly inserted TCP option data or logical null

    /// (TcpOption#isNull() == true) if insertion failed. In case of a failure a corresponding error message will be

    /// printed to log

    TcpOption insertTcpOptionAfter(const TcpOptionBuilder& optionBuilder,

                                   TcpOptionEnumType prevOptionType = TcpOptionEnumType::Unknown);

    /// @deprecated This method is deprecated, please use removeTcpOption(TcpOptionEnumType)

    PCPP_DEPRECATED_TCP_OPTION_TYPE

    bool removeTcpOption(TcpOptionType optionType);

    /// Remove an existing TCP option from the layer. TCP option is found by type

    /// @param[in] optionType The TCP option type to remove

    /// @return True if TCP option was removed or false if type wasn't found or if removal failed (in each case a

    /// proper error will be written to log)

    bool removeTcpOption(TcpOptionEnumType optionType);

    /// Remove all TCP options in this layer

    /// @return True if all TCP options were successfully removed or false if removal failed for some reason

    /// (a proper error will be written to log)

    bool removeAllTcpOptions();

    /// Calculate the checksum from header and data and possibly write the result to @ref tcphdr#headerChecksum

    /// @param[in] writeResultToPacket If set to true then checksum result will be written to @ref

    /// tcphdr#headerChecksum

    /// @return The checksum result

    uint16_t calculateChecksum(bool writeResultToPacket);

    /// The static method makes validation of input data

    /// @param[in] data The pointer to the beginning of byte stream of TCP packet

    /// @param[in] dataLen The length of byte stream

    /// @return True if the data is valid and can represent a TCP packet

    static inline bool isDataValid(const uint8_t* data, size_t dataLen);

    // implement abstract methods

    /// Currently identifies the following next layers: HttpRequestLayer, HttpResponseLayer. Otherwise sets

    /// PayloadLayer

    void parseNextLayer() override;

    /// @return Size of @ref tcphdr + all TCP options

    size_t getHeaderLen() const override

    {

      return getTcpHeader()->dataOffset * 4;

    }

    /// Calculate @ref tcphdr#headerChecksum field

    void computeCalculateFields() override;

    std::string toString() const override;

    OsiModelLayer getOsiModelLayer() const override

    {

      return OsiModelTransportLayer;

    }

  private:

    TLVRecordReader<TcpOption> m_OptionReader;

    int m_NumOfTrailingBytes;

    void initLayer();

    uint8_t* getOptionsBasePtr() const

    {

      return m_Data + sizeof(tcphdr);

    }

    TcpOption addTcpOptionAt(const TcpOptionBuilder& optionBuilder, int offset);

    void adjustTcpOptionTrailer(size_t totalOptSize);

    void copyLayerData(const TcpLayer& other);

  };

  // implementation of inline methods

  bool TcpLayer::isDataValid(const uint8_t* data, size_t dataLen)

  {

    const tcphdr* hdr = reinterpret_cast<const tcphdr*>(data);

    return dataLen >= sizeof(tcphdr) && hdr->dataOffset >= 5 /* the minimum TCP header size */

           && dataLen >= hdr->dataOffset * sizeof(uint32_t);

  }

}  // namespace pcpp

#undef PCPP_DEPRECATED_TCP_OPTION_TYPE