/*
    Copyright 2015-2016 Amebis
    Copyright 2016 GÉANT

    This file is part of GÉANTLink.

    GÉANTLink is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    GÉANTLink is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with GÉANTLink. If not, see <http://www.gnu.org/licenses/>.
*/

namespace eap
{
    ///
    /// EAP-TLS method
    ///
    class method_tls;
}

#pragma once

#include "../include/Config.h"
#include "../include/Credentials.h"

#include "../../EAPBase/include/Method.h"

#include <WinStd/Crypt.h>

#include <list>
#include <vector>


namespace eap
{
    class method_tls : public method
    {
    public:
        ///
        /// EAP-TLS request packet flags
        ///
        /// \sa [The EAP-TLS Authentication Protocol (Chapter: 3.1 EAP-TLS Request Packet)](https://tools.ietf.org/html/rfc5216#section-3.1)
        ///
        enum flags_req_t {
            flags_req_length_incl = 0x80,   ///< Length included
            flags_req_more_frag   = 0x40,   ///< More fragments
            flags_req_start       = 0x20,   ///< Start
        };

        ///
        /// EAP-TLS response packet flags
        ///
        /// \sa [The EAP-TLS Authentication Protocol (Chapter: 3.2 EAP-TLS Response Packet)](https://tools.ietf.org/html/rfc5216#section-3.2)
        ///
        enum flags_res_t {
            flags_res_length_incl = 0x80,   ///< Length included
            flags_res_more_frag   = 0x40,   ///< More fragments
        };

        ///
        /// TLS packet type
        ///
        /// \sa [The Transport Layer Security (TLS) Protocol Version 1.2 (Chapter: A.1. Record Layer](https://tools.ietf.org/html/rfc5246#appendix-A.1)
        ///
        enum message_type_t  {
            message_type_change_cipher_spec = 20,
            message_type_alert              = 21,
            message_type_handshake          = 22,
            message_type_application_data   = 23,
        };

        ///
        /// TLS handshake type
        ///
        /// \sa [The Transport Layer Security (TLS) Protocol Version 1.2 (Chapter: A.4. Handshake Protocol](https://tools.ietf.org/html/rfc5246#appendix-A.4)
        ///
        enum handshake_type_t {
            hello_request       =  0,
            client_hello        =  1,
            server_hello        =  2,
            certificate         = 11,
            server_key_exchange = 12,
            certificate_request = 13,
            server_hello_done   = 14,
            certificate_verify  = 15,
            client_key_exchange = 16,
            finished            = 20
        };

        ///
        /// EAP-TLS packet (data)
        ///
        class packet
        {
        public:
            ///
            /// Constructs an empty packet
            ///
            packet();

            ///
            /// Copies a packet
            ///
            /// \param[in] other  Packet to copy from
            ///
            packet(_In_ const packet &other);

            ///
            /// Moves a packet
            ///
            /// \param[in] other  Packet to move from
            ///
            packet(_Inout_ packet &&other);

            ///
            /// Copies a packet
            ///
            /// \param[in] other  Packet to copy from
            ///
            /// \returns Reference to this object
            ///
            packet& operator=(_In_ const packet &other);

            ///
            /// Moves a packet
            ///
            /// \param[in] other  Packet to move from
            ///
            /// \returns Reference to this object
            ///
            packet& operator=(_Inout_ packet &&other);

            ///
            /// Empty the packet
            ///
            void clear();

        public:
            EapCode m_code;                             ///< Packet code
            unsigned char m_id;                         ///< Packet ID
            unsigned char m_flags;                      ///< Packet flags
            std::vector<unsigned char> m_data;          ///< Packet data
        };

#pragma pack(push)
#pragma pack(1)
        ///
        /// TLS client/server random
        ///
        struct random
        {
            __time32_t time;        ///< Unix time-stamp
            unsigned char data[28]; ///< Randomness

            ///
            /// Constructs a all-zero random
            ///
            random();

            ///
            /// Copies a random
            ///
            /// \param[in] other  Random to copy from
            ///
            random(_In_ const random &other);

            ///
            /// Destructor
            ///
            ~random();

            ///
            /// Copies a random
            ///
            /// \param[in] other  Random to copy from
            ///
            /// \returns Reference to this object
            ///
            random& operator=(_In_ const random &other);

            ///
            /// Empty the random
            ///
            void clear();
        };
#pragma pack(pop)

#pragma pack(push)
#pragma pack(1)
        ///
        /// TLS message
        ///
        struct message
        {
            unsigned char type;         ///< Message type (one of `message_type_t` constants)
            struct {
                unsigned char major;    ///< Major version
                unsigned char minor;    ///< Minor version
            } version;                  ///< SSL/TLS version
            unsigned char length[2];    ///< Message length (in network byte order)
            unsigned char data[1];      ///< Message data
        };
#pragma pack(pop)

    public:
        ///
        /// Constructs an EAP method
        ///
        /// \param[in] mod  EAP module to use for global services
        /// \param[in] cfg  Method configuration
        ///
        method_tls(_In_ module &module, _In_ config_method_tls &cfg, _In_ credentials_tls &cred);

        ///
        /// Copies an EAP method
        ///
        /// \param[in] other  EAP method to copy from
        ///
        method_tls(_In_ const method_tls &other);

        ///
        /// Moves an EAP method
        ///
        /// \param[in] other  EAP method to move from
        ///
        method_tls(_Inout_ method_tls &&other);

        ///
        /// Copies an EAP method
        ///
        /// \param[in] other  EAP method to copy from
        ///
        /// \returns Reference to this object
        ///
        method_tls& operator=(_In_ const method_tls &other);

        ///
        /// Moves an EAP method
        ///
        /// \param[in] other  EAP method to move from
        ///
        /// \returns Reference to this object
        ///
        method_tls& operator=(_Inout_ method_tls &&other);

        /// \name Packet processing
        /// @{

        ///
        /// Starts an EAP authentication session on the peer EAPHost using the EAP method.
        ///
        /// \sa [EapPeerBeginSession function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363600.aspx)
        ///
        virtual void begin_session(
            _In_        DWORD         dwFlags,
            _In_  const EapAttributes *pAttributeArray,
            _In_        HANDLE        hTokenImpersonateUser,
            _In_        DWORD         dwMaxSendPacketSize);

        ///
        /// Processes a packet received by EAPHost from a supplicant.
        ///
        /// \sa [EapPeerProcessRequestPacket function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363621.aspx)
        ///
        virtual void process_request_packet(
            _In_bytecount_(dwReceivedPacketSize) const EapPacket           *pReceivedPacket,
            _In_                                       DWORD               dwReceivedPacketSize,
            _Inout_                                    EapPeerMethodOutput *pEapOutput);

        ///
        /// Obtains a response packet from the EAP method.
        ///
        /// \sa [EapPeerGetResponsePacket function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363610.aspx)
        ///
        virtual void get_response_packet(
            _Inout_bytecap_(*dwSendPacketSize) EapPacket *pSendPacket,
            _Inout_                            DWORD     *pdwSendPacketSize);

        ///
        /// Obtains the result of an authentication session from the EAP method.
        ///
        /// \sa [EapPeerGetResult function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363611.aspx)
        ///
        virtual void get_result(
            _In_    EapPeerMethodResultReason reason,
            _Inout_ EapPeerMethodResult       *ppResult);

        /// @}

    protected:
        ///
        /// Makes a TLS client hello message
        ///
        /// \sa [The Transport Layer Security (TLS) Protocol Version 1.2 (Chapter 7.4.1.2. Client Hello)](https://tools.ietf.org/html/rfc5246#section-7.4.1.2)
        ///
        /// \returns Client Hello message
        ///
        sanitizing_blob make_client_hello() const;

        ///
        /// Makes a TLS handshake
        ///
        /// \sa [The Transport Layer Security (TLS) Protocol Version 1.2 (Chapter A.1. Record Layer)](https://tools.ietf.org/html/rfc5246#appendix-A.1)
        ///
        /// \param[in]  msg         Handshake data contents
        ///
        /// \returns TLS handshake message
        ///
        static eap::sanitizing_blob make_handshake(_In_ const sanitizing_blob &msg);

        ///
        /// Processes a TLS handshake
        ///
        /// \sa [The Transport Layer Security (TLS) Protocol Version 1.2 (Chapter A.1. Record Layer)](https://tools.ietf.org/html/rfc5246#appendix-A.1)
        ///
        /// \param[in] msg      TLS handshake message data
        /// \param[in] msg_size TLS handshake message data size
        ///
        void process_handshake(_In_bytecount_(msg_size) const void *msg, _In_ size_t msg_size);

        ///
        /// Encrypt TLS message
        ///
        /// \param[inout] msg         TLS message to encrypt
        ///
        void encrypt_message(_Inout_ sanitizing_blob &msg);

        ///
        /// Decrypt TLS message
        ///
        /// \param[inout] msg  TLS message to decrypt
        ///
        void decrypt_message(_Inout_ sanitizing_blob &msg);

        ///
        /// Calculates pseudo-random P_hash data defined in RFC 5246
        ///
        /// \sa [The Transport Layer Security (TLS) Protocol Version 1.2 (Chapter: 5. HMAC and the Pseudorandom Function)](https://tools.ietf.org/html/rfc5246#section-5)
        ///
        /// \param[in]  alg          Hashing algorithm to use (CALG_MD5 or CALG_SHA1)
        /// \param[in]  secret       Hashing secret key
        /// \param[in]  size_secret  \p secret size
        /// \param[in]  seed         Hashing seed
        /// \param[in]  size_seed    \p seed size
        /// \param[in]  size         Minimum number of bytes of pseudo-random data required
        ///
        /// \returns Generated pseudo-random data (\p size or longer)
        ///
        std::vector<unsigned char> p_hash(
            _In_                              ALG_ID alg,
            _In_bytecount_(size_secret) const void   *secret,
            _In_                              size_t size_secret,
            _In_bytecount_(size_seed)   const void   *seed,
            _In_                              size_t size_seed,
            _In_                              size_t size);

        ///
        /// HMAC symmetric key generation
        ///
        /// \param[in]  alg          Hashing algorithm to use (CALG_MD5 or CALG_SHA1)
        /// \param[in]  secret       Hashing secret key
        /// \param[in]  size_secret  \p secret size
        ///
        /// \returns Key
        ///
        inline HCRYPTKEY derive_hmac_key(
            _In_                              ALG_ID alg,
            _In_bytecount_(size_secret) const void   *secret,
            _In_                              size_t size_secret)
        {
            winstd::crypt_hash hash;
            if (!hash.create(m_cp, alg, 0, 0))
                throw winstd::win_runtime_error(__FUNCTION__ " Error creating key hash.");
            if (!CryptHashData(hash, (const BYTE*)secret, (DWORD)size_secret, 0))
                throw winstd::win_runtime_error(__FUNCTION__ " Error hashing secret.");
            winstd::crypt_key key;
            key.derive(m_cp, CALG_RC4, hash, 0);
            return key.detach();
        }

        ///
        /// Creates HMAC hash
        ///
        /// \param[in] key   HMAC key
        /// \param[in] info  Additional HMAC parameters
        ///
        /// \returns Hash
        ///
        inline HCRYPTHASH create_hmac_hash(
            _In_       HCRYPTKEY key,
            _In_ const HMAC_INFO info)
        {
            winstd::crypt_hash hash;
            if (!hash.create(m_cp, CALG_HMAC, key, 0))
                throw winstd::win_runtime_error(__FUNCTION__ " Error creating HMAC hash.");
            if (!CryptSetHashParam(hash, HP_HMAC_INFO, (const BYTE*)&info, 0))
                throw winstd::win_runtime_error(__FUNCTION__ " Error setting HMAC hash parameters.");
            return hash.detach();
        }

    public:
        enum phase_t {
            phase_unknown      = -1,
            phase_client_hello =  0,
            phase_server_hello =  1,
        } m_phase;                                              ///< Session phase

        packet m_packet_req;                                    ///< Request packet
        packet m_packet_res;                                    ///< Response packet

        winstd::crypt_prov m_cp;                                ///< Cryptography provider
        winstd::crypt_key m_key_hmac;                           ///< Symmetric key for HMAC calculation

        winstd::crypt_key m_key_encrypt;                        ///< Key for encrypting messages
        winstd::crypt_key m_key_decrypt;                        ///< Key for decrypting messages

        random m_random_client;                                 ///< Client random
        random m_random_server;                                 ///< Server random

        sanitizing_blob m_session_id;                           ///< TLS session ID

        std::list<winstd::cert_context> m_server_cert_chain;    ///< Server certificate chain

        bool m_send_client_cert;                                ///< Did server request client certificate?

        winstd::crypt_hash m_hash_handshake_msgs_md5;           ///< Running MD5 hash of handshake messages sent
        winstd::crypt_hash m_hash_handshake_msgs_sha1;          ///< Running SHA-1 hash of handshake messages sent

    protected:
        unsigned __int64 m_seq_num;                             ///< Sequence number for encryption
    };
}