lime_impl.hpp

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/*
    lime_impl.hpp
    @author Johan Pascal
    @copyright  Copyright (C) 2017  Belledonne Communications SARL

    This program 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.

    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef lime_impl_hpp
#define lime_impl_hpp

#include <memory>
#include <vector>
#include <unordered_map>
#include <queue>
#include <mutex>

#include "lime/lime.hpp"
#include "lime_lime.hpp"
#include "lime_crypto_primitives.hpp"
#include "lime_localStorage.hpp"
#include "lime_double_ratchet.hpp"
#include "lime_x3dh.hpp"
#include "lime_x3dh_protocol.hpp"

namespace lime {
    // an enum used by network state engine to manage sequence packet sending(at user creation)
    enum class network_state : uint8_t {done=0x00, sendSPk=0x01, sendOPk=0x02};

    struct callbackUserData;

    template <typename Curve>
    class Lime : public LimeGeneric, public std::enable_shared_from_this<Lime<Curve>> {
        private:
            /*** data members ***/
            /* general purpose */
            std::shared_ptr<RNG> m_RNG; // Random Number Generator context
            std::string m_selfDeviceId; // self device Id, shall be the GRUU
            std::mutex m_mutex; // a mutex to lock own thread sensitive ressources (m_DR_sessions_cache, encryption_queue)

            /* X3DH engine */
            std::shared_ptr<X3DH> m_X3DH; // manage X3DH operations

            /* local storage related */
            std::shared_ptr<lime::Db> m_localStorage; // shared pointer would be used/stored in Double Ratchet Sessions
            long int m_db_Uid; // the Uid in database, retrieved at creation/load, used for faster access

            /* Double ratchet related */
            std::unordered_map<std::string, std::shared_ptr<DR>> m_DR_sessions_cache; // store already loaded DR session

            /* encryption queue: encryption requesting asynchronous operation(connection to X3DH server) are queued to avoid repeating a request to server */
            std::shared_ptr<callbackUserData> m_ongoing_encryption;
            std::queue<std::shared_ptr<callbackUserData>> m_encryption_queue;

            /*** Private functions ***/
            void cache_DR_sessions(std::vector<RecipientInfos> &internal_recipients, std::vector<std::string> &missing_devices); // loop on internal recipient an try to load in DR session cache the one which have no session attached 
            void get_DRSessions(const std::string &senderDeviceId, const long int ignoreThisDRSessionId, std::vector<std::shared_ptr<DR>> &DRSessions); // load from local storage in DRSessions all DR session matching the peerDeviceId, ignore the one picked by id in 2nd arg

        public: /* Implement API defined in lime_lime.hpp in LimeGeneric abstract class */
            Lime(std::shared_ptr<lime::Db> localStorage, const std::string &deviceId, const std::string &url, const limeX3DHServerPostData &X3DH_post_data, const long int Uid = 0);
            ~Lime();
            Lime(Lime<Curve> &a) = delete; // can't copy a session, force usage of shared pointers
            Lime<Curve> &operator=(Lime<Curve> &a) = delete; // can't copy a session

            void publish_user(const std::shared_ptr<limeCallback> callback, const uint16_t OPkInitialBatchSize) override;
            void delete_user(const std::shared_ptr<limeCallback> callback) override;
            void delete_peerDevice(const std::string &peerDeviceId) override;
            void update_SPk(const std::shared_ptr<limeCallback> callback) override;
            void update_OPk(const std::shared_ptr<limeCallback> callback, uint16_t OPkServerLowLimit, uint16_t OPkBatchSize) override;
            void get_Ik(std::vector<uint8_t> &Ik) override;
            void encrypt(std::shared_ptr<lime::EncryptionContext> encryptionContext, const std::shared_ptr<limeCallback> callback, const std::shared_ptr<limeRandomSeedCallback> randomSeedCallback) override;
            lime::PeerDeviceStatus decrypt(const std::vector<uint8_t> &recipientUserId, const std::string &senderDeviceId, const std::vector<uint8_t> &DRmessage, const std::vector<uint8_t> &cipherMessage, std::vector<uint8_t> &plainMessage) override;
            void set_x3dhServerUrl(const std::string &x3dhServerUrl) override;
            std::string get_x3dhServerUrl() override;
            void stale_sessions(const std::string &peerDeviceId) override;
            void processEncryptionQueue(void) override;
            void DRcache_delete(const std::string &deviceId) override;
            void DRcache_insert(const std::string &deviceId, std::shared_ptr<DR> DRsession) override;
            std::shared_ptr<X3DH> get_X3DH(void) override {return m_X3DH;}
            std::unique_lock<std::mutex> lock(void) override {return std::unique_lock<std::mutex>(m_mutex);}
    };

    struct callbackUserData {
        std::weak_ptr<LimeGeneric> limeObj;
        const std::shared_ptr<limeCallback> callback;
        const std::shared_ptr<limeRandomSeedCallback> randomSeedCallback;
        std::shared_ptr<lime::EncryptionContext> encryptionContext;
        uint16_t OPkServerLowLimit;
        uint16_t OPkBatchSize;

        callbackUserData(std::weak_ptr<LimeGeneric> thiz, const std::shared_ptr<limeCallback> callback, uint16_t OPkInitialBatchSize=lime::settings::OPk_initialBatchSize)
            : limeObj{thiz}, callback{callback}, randomSeedCallback{nullptr},
            encryptionContext{nullptr}, OPkServerLowLimit(0), OPkBatchSize(OPkInitialBatchSize) {};

        callbackUserData(std::weak_ptr<LimeGeneric> thiz, const std::shared_ptr<limeCallback> callback, uint16_t OPkServerLowLimit, uint16_t OPkBatchSize)
            : limeObj{thiz}, callback{callback}, randomSeedCallback{nullptr},
            encryptionContext{nullptr}, OPkServerLowLimit{OPkServerLowLimit}, OPkBatchSize{OPkBatchSize} {};

        callbackUserData(std::weak_ptr<LimeGeneric> thiz, const std::shared_ptr<limeCallback> callback, const std::shared_ptr<limeRandomSeedCallback> randomSeedCallback,
                std::shared_ptr<lime::EncryptionContext> encryptionContext)
            : limeObj{thiz}, callback{callback}, randomSeedCallback{randomSeedCallback},
            encryptionContext{encryptionContext}, OPkServerLowLimit(0), OPkBatchSize(0) {};

        callbackUserData(callbackUserData &a) = delete;
        callbackUserData operator=(callbackUserData &a) = delete;
    };


/* this template is intanciated in lime.cpp, do not re-instanciate it anywhere else */
#ifdef EC25519_ENABLED
    extern template class Lime<C255>;
#endif

#ifdef EC448_ENABLED
    extern template class Lime<C448>;
#endif
#ifdef HAVE_BCTBXPQ
#ifdef EC25519_ENABLED
    extern template class Lime<C255K512>;
    extern template class Lime<C255MLK512>;
#endif
#ifdef EC448_ENABLED
    extern template class Lime<C448MLK1024>;
#endif
#endif

}
#endif /* lime_impl_hpp */