/*
    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 module base class
    ///
    /// Provides basic services to EAP methods.
    ///
    class module;

    ///
    /// EAP peer base class
    ///
    /// A group of methods all EAP peers must or should implement.
    ///
    template <class _Tmeth, class _Tcred, class _Tint, class _Tintres> class peer_base;

    ///
    /// EAP peer base class
    ///
    /// A group of methods all EAP peers must or should implement.
    ///
    template <class _Tmeth, class _Tcred, class _Tint, class _Tintres> class peer;
}

#pragma once

#include "EAP.h"

#include <WinStd/Crypt.h>
#include <WinStd/ETW.h>
#include <WinStd/Win.h>

#include <Windows.h>
#include <eaptypes.h> // Must include after <Windows.h>
#include <sal.h>
#include <tchar.h>

#include <EventsETW.h> // Must include after <Windows.h>


namespace eap
{
    class module
    {
    public:
        ///
        /// Constructs a module for the given EAP type
        ///
        /// \param[in] eap_method  EAP method type ID
        ///
        module(_In_ winstd::eap_type_t eap_method = winstd::eap_type_undefined);

        ///
        /// Destructs the module
        ///
        virtual ~module();

        /// \name Memory management
        /// @{

        ///
        /// Allocate a EAP_ERROR and fill it according to dwErrorCode
        ///
        EAP_ERROR* make_error(_In_ DWORD dwErrorCode, _In_opt_z_ LPCWSTR pszRootCauseString = NULL, _In_opt_z_ LPCWSTR pszRepairString = NULL, _In_opt_ DWORD dwReasonCode = 0, _In_opt_ LPCGUID pRootCauseGuid = NULL, _In_opt_ LPCGUID pRepairGuid = NULL, _In_opt_ LPCGUID pHelpLinkGuid = NULL) const;

        ///
        /// Allocate BLOB
        ///
        BYTE* alloc_memory(_In_ size_t size);

        ///
        /// Free BLOB allocated with this peer
        ///
        void free_memory(_In_ BYTE *ptr);

        ///
        /// Free EAP_ERROR allocated with `make_error()` method
        ///
        void free_error_memory(_In_ EAP_ERROR *err);

        ///
        /// Makes a new method config for the given method type
        ///
        virtual config_method* make_config_method();

        /// @}

        /// \name Logging
        /// @{

        ///
        /// Writes EAPMETHOD_TRACE_EVT_FN_CALL and returns auto event writer class
        ///
        /// \param[in] pszFnName  Function name
        ///
        /// \returns A new auto event writer that writes EAPMETHOD_TRACE_EVT_FN_RETURN event on destruction
        ///
        inline winstd::event_fn_auto get_event_fn_auto(_In_z_ LPCSTR pszFnName) const
        {
            return winstd::event_fn_auto(m_ep, &EAPMETHOD_TRACE_EVT_FN_CALL, &EAPMETHOD_TRACE_EVT_FN_RETURN, pszFnName);
        }

        ///
        /// Writes EAPMETHOD_TRACE_EVT_FN_CALL and returns auto event writer class
        ///
        /// \param[in] pszFnName  Function name
        ///
        /// \returns A new auto event writer that writes EAPMETHOD_TRACE_EVT_FN_RETURN_DWORD event on destruction
        ///
        inline winstd::event_fn_auto_ret<DWORD> get_event_fn_auto(_In_z_ LPCSTR pszFnName, _In_ DWORD &result) const
        {
            return winstd::event_fn_auto_ret<DWORD>(m_ep, &EAPMETHOD_TRACE_EVT_FN_CALL, &EAPMETHOD_TRACE_EVT_FN_RETURN_DWORD, pszFnName, result);
        }

        ///
        /// Logs error
        ///
        void log_error(_In_ const EAP_ERROR *err) const;

        ///
        /// Logs Unicode string config value
        ///
        inline void log_config(_In_z_ LPCWSTR name, _In_z_ LPCWSTR value) const
        {
            m_ep.write(&EAPMETHOD_TRACE_EVT_CFG_VALUE_UNICODE_STRING, winstd::event_data(name), winstd::event_data(value), winstd::event_data::blank);
        }

        ///
        /// Logs string list config value
        ///
        template<class _Traits, class _Ax, class _Ax_list>
        inline void log_config(_In_z_ LPCWSTR name, _In_z_ const std::list<std::basic_string<char, _Traits, _Ax>, _Ax_list> &value) const
        {
            // Prepare a table of event data descriptors.
            std::vector<EVENT_DATA_DESCRIPTOR> desc;
            size_t count = value.size();
            desc.reserve(count + 2);
            desc.push_back(winstd::event_data(              name ));
            desc.push_back(winstd::event_data((unsigned int)count));
            for (std::list<std::basic_string<char, _Traits, _Ax>, _Ax_list>::const_iterator v = value.cbegin(), v_end = value.cend(); v != v_end; ++v)
                desc.push_back(winstd::event_data(*v));

            m_ep.write(&EAPMETHOD_TRACE_EVT_CFG_VALUE_ANSI_STRING_ARRAY, (ULONG)desc.size(), desc.data());
        }

        ///
        /// Logs Unicode string list config value
        ///
        template<class _Traits, class _Ax, class _Ax_list>
        inline void log_config(_In_z_ LPCWSTR name, _In_z_ const std::list<std::basic_string<wchar_t, _Traits, _Ax>, _Ax_list> &value) const
        {
            // Prepare a table of event data descriptors.
            std::vector<EVENT_DATA_DESCRIPTOR> desc;
            size_t count = value.size();
            desc.reserve(count + 2);
            desc.push_back(winstd::event_data(              name ));
            desc.push_back(winstd::event_data((unsigned int)count));
            for (std::list<std::basic_string<wchar_t, _Traits, _Ax>, _Ax_list>::const_iterator v = value.cbegin(), v_end = value.cend(); v != v_end; ++v)
                desc.push_back(winstd::event_data(*v));

            m_ep.write(&EAPMETHOD_TRACE_EVT_CFG_VALUE_UNICODE_STRING_ARRAY, (ULONG)desc.size(), desc.data());
        }

        ///
        /// Logs boolean config value
        ///
        inline void log_config(_In_z_ LPCWSTR name, _In_ bool value) const
        {
            m_ep.write(&EAPMETHOD_TRACE_EVT_CFG_VALUE_BOOL, winstd::event_data(name), winstd::event_data((int)value), winstd::event_data::blank);
        }

        ///
        /// Logs event
        ///
        inline void log_event(_In_ PCEVENT_DESCRIPTOR EventDescriptor, ...) const
        {
            va_list arg;
            va_start(arg, EventDescriptor);
            m_ep.write(EventDescriptor, arg);
            va_end(arg);
        }

        /// @}

        /// \name Encryption
        /// @{

        ///
        /// Encrypts data
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data to encrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] enc         Encrypted data
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        /// \param[out] hHash       Handle of hashing object
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        bool encrypt(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::vector<unsigned char> &enc, _Out_ EAP_ERROR **ppEapError, _Out_opt_ HCRYPTHASH hHash = NULL) const;


        ///
        /// Encrypts a string
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] val         String to encrypt
        /// \param[out] enc         Encrypted data
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        /// \param[out] hHash       Handle of hashing object
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Elem, class _Traits, class _Ax>
        bool encrypt(_In_ HCRYPTPROV hProv, _In_ const std::basic_string<_Elem, _Traits, _Ax> &val, _Out_ std::vector<unsigned char> &enc, _Out_ EAP_ERROR **ppEapError, _Out_opt_ HCRYPTHASH hHash = NULL) const
        {
            return encrypt(hProv, val.c_str(), val.length()*sizeof(_Elem), enc, ppEapError, hHash);
        }


        ///
        /// Encrypts a wide string
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] val         String to encrypt
        /// \param[out] enc         Encrypted data
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        /// \param[out] hHash       Handle of hashing object
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Traits, class _Ax>
        bool encrypt(_In_ HCRYPTPROV hProv, _In_ const std::basic_string<wchar_t, _Traits, _Ax> &val, _Out_ std::vector<unsigned char> &enc, _Out_ EAP_ERROR **ppEapError, _Out_opt_ HCRYPTHASH hHash = NULL) const
        {
            winstd::sanitizing_string val_utf8;
            WideCharToMultiByte(CP_UTF8, 0, val.c_str(), (int)val.length(), val_utf8, NULL, NULL);
            return encrypt(hProv, val_utf8, enc, ppEapError, hHash);
        }


        ///
        /// Encrypts data and add MD5 hash for integrity check
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data to encrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] enc         Encrypted data with 16B MD5 hash appended
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        bool encrypt_md5(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::vector<unsigned char> &enc, _Out_ EAP_ERROR **ppEapError) const;


        ///
        /// Encrypts a string and add MD5 hash for integrity check
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] val         String to encrypt
        /// \param[out] enc         Encrypted data with 16B MD5 hash appended
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Elem, class _Traits, class _Ax>
        bool encrypt_md5(_In_ HCRYPTPROV hProv, _In_ const std::basic_string<_Elem, _Traits, _Ax> &val, _Out_ std::vector<unsigned char> &enc, _Out_ EAP_ERROR **ppEapError) const
        {
            return encrypt_md5(hProv, val.c_str(), val.length()*sizeof(_Elem), enc, ppEapError);
        }


        ///
        /// Encrypts a wide string and add MD5 hash for integrity check
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] val         String to encrypt
        /// \param[out] enc         Encrypted data with 16B MD5 hash appended
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Traits, class _Ax>
        bool encrypt_md5(_In_ HCRYPTPROV hProv, _In_ const std::basic_string<wchar_t, _Traits, _Ax> &val, _Out_ std::vector<unsigned char> &enc, _Out_ EAP_ERROR **ppEapError) const
        {
            winstd::sanitizing_string val_utf8;
            WideCharToMultiByte(CP_UTF8, 0, val.c_str(), (int)val.length(), val_utf8, NULL, NULL);
            return encrypt_md5(hProv, val_utf8, enc, ppEapError);
        }


        ///
        /// Decrypts data
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data to decrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] dec         Decrypted data
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        /// \param[out] hHash       Handle of hashing object
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Ty, class _Ax>
        bool decrypt(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::vector<_Ty, _Ax> &dec, _Out_ EAP_ERROR **ppEapError, _Out_opt_ HCRYPTHASH hHash = NULL) const
        {
            assert(ppEapError);

            // Import the private RSA key.
            HRSRC res = FindResource(m_instance, MAKEINTRESOURCE(IDR_EAP_KEY_PRIVATE), RT_RCDATA);
            assert(res);
            HGLOBAL res_handle = LoadResource(m_instance, res);
            assert(res_handle);
            crypt_key key_rsa;
            unique_ptr<unsigned char[], LocalFree_delete<unsigned char[]> > keyinfo_data;
            DWORD keyinfo_size = 0;
            if (!CryptDecodeObjectEx(X509_ASN_ENCODING, PKCS_RSA_PRIVATE_KEY, (const BYTE*)::LockResource(res_handle), ::SizeofResource(m_instance, res), CRYPT_DECODE_ALLOC_FLAG, NULL, &keyinfo_data, &keyinfo_size)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" CryptDecodeObjectEx failed."));
                return false;
            }
            if (!key_rsa.import(hProv, keyinfo_data.get(), keyinfo_size, NULL, 0)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" Private key import failed."));
                return false;
            }

            // Import the 256-bit AES session key.
            crypt_key key_aes;
            if (!CryptImportKey(hProv, (LPCBYTE)data, 268, key_rsa, 0, &key_aes)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" CryptImportKey failed."));
                return false;
            }

            // Decrypt the data using AES session key.
            vector<unsigned char, sanitizing_allocator<unsigned char> > buf;
            buf.assign((const unsigned char*)data + 268, (const unsigned char*)data + size);
            if (!CryptDecrypt(key_aes, hHash, TRUE, 0, buf)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" CryptDecrypt failed."));
                return false;
            }
            dec.assign(buf.begin(), buf.end());

            return true;
        }


        ///
        /// Decrypts a string
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data to decrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] dec         Decrypted string
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        /// \param[out] hHash       Handle of hashing object
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Elem, class _Traits, class _Ax>
        bool decrypt(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::basic_string<_Elem, _Traits, _Ax> &dec, _Out_ EAP_ERROR **ppEapError, _Out_opt_ HCRYPTHASH hHash = NULL) const
        {
            std::vector<_Elem, sanitizing_allocator<_Elem> > buf;
            if (!decrypt(hProv, data, size, buf, ppEapError, hHash))
                return false;
            dec.assign(buf.data(), buf.size());

            return true;
        }


        ///
        /// Decrypts a wide string
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data to decrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] dec         Decrypted string
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        /// \param[out] hHash       Handle of hashing object
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Traits, class _Ax>
        bool decrypt(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::basic_string<wchar_t, _Traits, _Ax> &dec, _Out_ EAP_ERROR **ppEapError, _Out_opt_ HCRYPTHASH hHash = NULL) const
        {
            winstd::sanitizing_string buf;
            if (!decrypt(hProv, data, size, buf, ppEapError, hHash))
                return false;
            MultiByteToWideChar(CP_UTF8, 0, buf.data(), (int)buf.size(), dec);

            return true;
        }


        ///
        /// Decrypts data with MD5 integrity check
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data with 16B MD5 hash appended to decrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] dec         Decrypted data
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Ty, class _Ax>
        bool decrypt_md5(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::vector<_Ty, _Ax> &dec, _Out_ EAP_ERROR **ppEapError) const
        {
            // Create hash.
            crypt_hash hash;
            if (!hash.create(hProv, CALG_MD5)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" Creating MD5 hash failed."));
                return false;
            }
            DWORD dwHashSize, dwHashSizeSize = sizeof(dwHashSize);
            CryptGetHashParam(hash, HP_HASHSIZE, (LPBYTE)&dwHashSize, &dwHashSizeSize, 0);
            if (size < dwHashSize) {
                *ppEapError = make_error(ERROR_INVALID_DATA, _T(__FUNCTION__) _T(" Encrypted data too short."));
                return false;
            }
            size_t enc_size = size - dwHashSize;

            // Decrypt data.
            if (!decrypt(hProv, data, enc_size, dec, ppEapError, hash))
                return false;

            // Calculate MD5 hash and verify it.
            vector<unsigned char> hash_bin;
            if (!CryptGetHashParam(hash, HP_HASHVAL, hash_bin, 0)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" Calculating MD5 hash failed."));
                return false;
            }
            if (memcmp((unsigned char*)data + enc_size, hash_bin.data(), dwHashSize) != 0) {
                *ppEapError = make_error(ERROR_INVALID_DATA, _T(__FUNCTION__) _T(" Invalid encrypted data."));
                return false;
            }

            return true;
        }


        ///
        /// Decrypts a string with MD5 integrity check
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data with 16B MD5 hash appended to decrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] dec         Decrypted string
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Elem, class _Traits, class _Ax>
        bool decrypt_md5(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::basic_string<_Elem, _Traits, _Ax> &dec, _Out_ EAP_ERROR **ppEapError) const
        {
            std::vector<_Elem, sanitizing_allocator<_Elem> > buf;
            if (!decrypt_md5(hProv, data, size, buf, ppEapError))
                return false;
            dec.assign(buf.data(), buf.size());

            return true;
        }


        ///
        /// Decrypts a wide string with MD5 integrity check
        ///
        /// \param[in ] hProv       Handle of cryptographics provider
        /// \param[in ] data        Pointer to data with 16B MD5 hash appended to decrypt
        /// \param[in ] size        Size of \p data in bytes
        /// \param[out] dec         Decrypted string
        /// \param[out] ppEapError  Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class _Traits, class _Ax>
        bool decrypt_md5(_In_ HCRYPTPROV hProv, _In_bytecount_(size) const void *data, _In_ size_t size, _Out_ std::basic_string<wchar_t, _Traits, _Ax> &dec, _Out_ EAP_ERROR **ppEapError) const
        {
            winstd::sanitizing_string buf;
            if (!decrypt_md5(hProv, data, size, buf, ppEapError))
                return false;
            MultiByteToWideChar(CP_UTF8, 0, buf.data(), (int)buf.size(), dec);

            return true;
        }

        /// @}

        /// \name BLOB management
        /// @{

        ///
        /// Unencrypts and unpacks the BLOB
        ///
        /// \param[inout] record        Object to unpack to
        /// \param[in   ] pDataIn       Pointer to encrypted BLOB
        /// \param[in   ] dwDataInSize  Size of \p pDataIn
        /// \param[out  ] ppEapError    Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class T>
        bool unpack(
            _Inout_                        T     &record,
            _In_count_(dwDataInSize) const BYTE  *pDataIn,
            _In_                           DWORD dwDataInSize,
            _Out_                          EAP_ERROR **ppEapError)
        {
#if EAP_ENCRYPT_BLOBS
            // Prepare cryptographics provider.
            winstd::crypt_prov cp;
            if (!cp.create(NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" CryptAcquireContext failed."));
                return false;
            }

            // Decrypt data.
            vector<unsigned char, sanitizing_allocator<unsigned char> > data;
            if (!decrypt_md5(cp, pDataIn, dwDataInSize, data, ppEapError))
                return false;

            cursor_in cursor = { data.data(), data.data() + data.size() };
#else
            UNREFERENCED_PARAMETER(ppEapError);

            cursor_in cursor = { pDataIn, pDataIn + dwDataInSize };
#endif
            cursor >> record;
            assert(cursor.ptr == cursor.ptr_end);

            return true;
        }


        ///
        /// Packs and encrypts to the BLOB
        ///
        /// \param[in ] record          Object to pack
        /// \param[out] ppDataOut       Pointer to pointer to receive encrypted BLOB. Pointer must be freed using `module::free_memory()`.
        /// \param[out] pdwDataOutSize  Pointer to \p ppDataOut size
        /// \param[out] ppEapError      Pointer to error descriptor in case of failure. Free using `module::free_error_memory()`.
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        template<class T>
        bool pack(
            _In_  const T         &record,
            _Out_       BYTE      **ppDataOut,
            _Out_       DWORD     *pdwDataOutSize,
            _Out_       EAP_ERROR **ppEapError)
        {
            assert(ppDataOut);
            assert(pdwDataOutSize);

#if EAP_ENCRYPT_BLOBS
            // Allocate BLOB.
            std::vector<unsigned char, winstd::sanitizing_allocator<unsigned char> > data;
            data.resize(pksizeof(record));

            // Pack to BLOB.
            cursor_out cursor = { data.data(), data.data() + data.size() };
            cursor << record;
            assert(cursor.ptr == cursor.ptr_end);

            // Prepare cryptographics provider.
            winstd::crypt_prov cp;
            if (!cp.create(NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT)) {
                *ppEapError = make_error(GetLastError(), _T(__FUNCTION__) _T(" CryptAcquireContext failed."));
                return false;
            }

            // Encrypt BLOB.
            std::vector<unsigned char> data_enc;
            if (!encrypt_md5(cp, data.data(), data.size(), data_enc, ppEapError))
                return false;

            // Copy encrypted BLOB to output.
            *pdwDataOutSize = (DWORD)data_enc.size();
            *ppDataOut = alloc_memory(*pdwDataOutSize);
            if (!*ppDataOut) {
                log_error(*ppEapError = g_peer.make_error(ERROR_OUTOFMEMORY, wstring_printf(_T(__FUNCTION__) _T(" Error allocating memory for BLOB (%uB)."), *pdwDataOutSize).c_str()));
                return false;
            }
            memcpy(*ppDataOut, data_enc.data(), *pdwDataOutSize);
#else
            // Allocate BLOB.
            *pdwDataOutSize = (DWORD)pksizeof(record);
            *ppDataOut = alloc_memory(*pdwDataOutSize);
            if (!*ppDataOut) {
                log_error(*ppEapError = g_peer.make_error(ERROR_OUTOFMEMORY, wstring_printf(_T(__FUNCTION__) _T(" Error allocating memory for BLOB (%uB)."), *pdwDataOutSize).c_str()));
                return false;
            }

            // Pack to BLOB.
            cursor_out cursor = { *ppDataOut, *ppDataOut + *pdwDataOutSize };
            cursor << record;
            assert(cursor.ptr == cursor.ptr_end);
            *pdwDataOutSize = cursor.ptr - *ppDataOut;
#endif

            return true;
        }

        /// @}

    public:
        HINSTANCE m_instance;                   ///< Windows module instance
        const winstd::eap_type_t m_eap_method;  ///< EAP method type

    protected:
        winstd::heap m_heap;                    ///< Heap
        mutable winstd::event_provider m_ep;    ///< Event Provider
    };


    template <class _Tmeth, class _Tcred, class _Tint, class _Tintres>
    class peer_base : public module
    {
    public:
        ///
        /// Method configuration data type
        ///
        typedef _Tmeth config_method_type;

        ///
        /// Credentials data type
        ///
        typedef _Tcred credentials_type;

        ///
        /// Interactive request data type
        ///
        typedef _Tint interactive_request_type;

        ///
        /// Interactive response data type
        ///
        typedef _Tintres interactive_response_type;

    public:
        ///
        /// Constructs a EAP peer module for the given EAP type
        ///
        /// \param[in] eap_method  EAP method type ID
        ///
        peer_base(_In_ winstd::eap_type_t eap_method) : module(eap_method) {}

        ///
        /// Makes a new method config for the given method type
        ///
        virtual config_method* make_config_method()
        {
            return new config_method_type(this);
        }
    };


    template <class _Tmeth, class _Tcred, class _Tint, class _Tintres>
    class peer : public peer_base<_Tmeth, _Tcred, _Tint, _Tintres>
    {
    public:
        ///
        /// Constructs a EAP peer module for the given EAP type
        ///
        /// \param[in] eap_method  EAP method type ID
        ///
        peer(_In_ winstd::eap_type_t eap_method) : peer_base<_Tmeth, _Tcred, _Tint, _Tintres>(eap_method) {}

        ///
        /// Initializes an EAP peer method for EAPHost.
        ///
        /// \sa [EapPeerGetInfo function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363613.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool initialize(_Out_ EAP_ERROR **ppEapError) = 0;

        ///
        /// Shuts down the EAP method and prepares to unload its corresponding DLL.
        ///
        /// \sa [EapPeerShutdown function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363627.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool shutdown(_Out_ EAP_ERROR **ppEapError) = 0;

        ///
        /// Returns the user data and user identity after being called by EAPHost.
        ///
        /// \sa [EapPeerGetIdentity function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363607.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool get_identity(
            _In_           DWORD            dwFlags,
            _In_     const config_providers &cfg,
            _In_opt_ const credentials_type *cred_in,
            _Inout_        credentials_type &cred_out,
            _In_           HANDLE           hTokenImpersonateUser,
            _Out_          BOOL             *pfInvokeUI,
            _Out_          WCHAR            **ppwszIdentity,
            _Out_          EAP_ERROR        **ppEapError) = 0;

        ///
        /// Defines the implementation of an EAP method-specific function that retrieves the properties of an EAP method given the connection and user data.
        ///
        /// \sa [EapPeerGetMethodProperties function](https://msdn.microsoft.com/en-us/library/windows/desktop/hh706636.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool get_method_properties(
            _In_        DWORD                     dwVersion,
            _In_        DWORD                     dwFlags,
            _In_        HANDLE                    hUserImpersonationToken,
            _In_  const config_providers          &cfg,
            _In_  const credentials_type          &cred,
            _Out_       EAP_METHOD_PROPERTY_ARRAY *pMethodPropertyArray,
            _Out_       EAP_ERROR                 **ppEapError) = 0;

        ///
        /// Defines the implementation of an EAP method-specific function that obtains the EAP Single-Sign-On (SSO) credential input fields for an EAP method.
        ///
        /// \sa [EapPeerQueryCredentialInputFields function](https://msdn.microsoft.com/en-us/library/windows/desktop/aa363622.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool query_credential_input_fields(
            _In_                                HANDLE                       hUserImpersonationToken,
            _In_                                DWORD                        dwFlags,
            _In_                                DWORD                        dwEapConnDataSize,
            _In_count_(dwEapConnDataSize) const BYTE                         *pEapConnData,
            _Out_                               EAP_CONFIG_INPUT_FIELD_ARRAY *pEapConfigInputFieldsArray,
            _Out_                               EAP_ERROR                    **ppEapError) const
        {
            UNREFERENCED_PARAMETER(hUserImpersonationToken);
            UNREFERENCED_PARAMETER(dwFlags);
            UNREFERENCED_PARAMETER(dwEapConnDataSize);
            UNREFERENCED_PARAMETER(pEapConnData);
            UNREFERENCED_PARAMETER(pEapConfigInputFieldsArray);
            UNREFERENCED_PARAMETER(ppEapError);

            *ppEapError = make_error(ERROR_NOT_SUPPORTED, _T(__FUNCTION__) _T(" Not supported."));
            return false;
        }

        ///
        /// Defines the implementation of an EAP method function that obtains the user BLOB data provided in an interactive Single-Sign-On (SSO) UI raised on the supplicant.
        ///
        /// \sa [EapPeerQueryUserBlobFromCredentialInputFields function](https://msdn.microsoft.com/en-us/library/windows/desktop/bb204697.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool query_user_blob_from_credential_input_fields(
            _In_                                HANDLE                       hUserImpersonationToken,
            _In_                                DWORD                        dwFlags,
            _In_                                DWORD                        dwEapConnDataSize,
            _In_count_(dwEapConnDataSize) const BYTE                         *pEapConnData,
            _In_                          const EAP_CONFIG_INPUT_FIELD_ARRAY *pEapConfigInputFieldArray,
            _Inout_                             DWORD                        *pdwUsersBlobSize,
            _Inout_                             BYTE                         **ppUserBlob,
            _Out_                               EAP_ERROR                    **ppEapError) const
        {
            UNREFERENCED_PARAMETER(hUserImpersonationToken);
            UNREFERENCED_PARAMETER(dwFlags);
            UNREFERENCED_PARAMETER(dwEapConnDataSize);
            UNREFERENCED_PARAMETER(pEapConnData);
            UNREFERENCED_PARAMETER(pEapConfigInputFieldArray);
            UNREFERENCED_PARAMETER(pdwUsersBlobSize);
            UNREFERENCED_PARAMETER(ppUserBlob);
            UNREFERENCED_PARAMETER(ppEapError);

            *ppEapError = make_error(ERROR_NOT_SUPPORTED, _T(__FUNCTION__) _T(" Not supported."));
            return false;
        }

        ///
        /// Defines the implementation of an EAP method API that provides the input fields for interactive UI components to be raised on the supplicant.
        ///
        /// \sa [EapPeerQueryInteractiveUIInputFields function](https://msdn.microsoft.com/en-us/library/windows/desktop/bb204695.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool query_interactive_ui_input_fields(
            _In_                                  DWORD                   dwVersion,
            _In_                                  DWORD                   dwFlags,
            _In_                                  DWORD                   dwUIContextDataSize,
            _In_count_(dwUIContextDataSize) const BYTE                    *pUIContextData,
            _Out_                                 EAP_INTERACTIVE_UI_DATA *pEapInteractiveUIData,
            _Out_                                 EAP_ERROR               **ppEapError,
            _Inout_                               LPVOID                  *pvReserved) const
        {
            UNREFERENCED_PARAMETER(dwVersion);
            UNREFERENCED_PARAMETER(dwFlags);
            UNREFERENCED_PARAMETER(dwUIContextDataSize);
            UNREFERENCED_PARAMETER(pUIContextData);
            UNREFERENCED_PARAMETER(pEapInteractiveUIData);
            UNREFERENCED_PARAMETER(ppEapError);
            UNREFERENCED_PARAMETER(pvReserved);

            *ppEapError = make_error(ERROR_NOT_SUPPORTED, _T(__FUNCTION__) _T(" Not supported."));
            return false;
        }

        ///
        /// Converts user information into a user BLOB that can be consumed by EAPHost run-time functions.
        ///
        /// \sa [EapPeerQueryUIBlobFromInteractiveUIInputFields function](https://msdn.microsoft.com/en-us/library/windows/desktop/bb204696.aspx)
        ///
        /// \returns
        /// - \c true if succeeded
        /// - \c false otherwise. See \p ppEapError for details.
        ///
        virtual bool query_ui_blob_from_interactive_ui_input_fields(
            _In_                                  DWORD                   dwVersion,
            _In_                                  DWORD                   dwFlags,
            _In_                                  DWORD                   dwUIContextDataSize,
            _In_count_(dwUIContextDataSize) const BYTE                    *pUIContextData,
            _In_                            const EAP_INTERACTIVE_UI_DATA *pEapInteractiveUIData,
            _Out_                                 DWORD                   *pdwDataFromInteractiveUISize,
            _Out_                                 BYTE                    **ppDataFromInteractiveUI,
            _Out_                                 EAP_ERROR               **ppEapError,
            _Inout_                               LPVOID                  *ppvReserved) const
        {
            UNREFERENCED_PARAMETER(dwVersion);
            UNREFERENCED_PARAMETER(dwFlags);
            UNREFERENCED_PARAMETER(dwUIContextDataSize);
            UNREFERENCED_PARAMETER(pUIContextData);
            UNREFERENCED_PARAMETER(pEapInteractiveUIData);
            UNREFERENCED_PARAMETER(pdwDataFromInteractiveUISize);
            UNREFERENCED_PARAMETER(ppDataFromInteractiveUI);
            UNREFERENCED_PARAMETER(ppEapError);
            UNREFERENCED_PARAMETER(ppvReserved);

            *ppEapError = make_error(ERROR_NOT_SUPPORTED, _T(__FUNCTION__) _T(" Not supported."));
            return false;
        }
    };
}