text: /**
   * \file      LoRaMac.h
   *
   * \brief     LoRa MAC layer implementation
   *
   * \copyright Revised BSD License, see LICENSE.TXT file include in the project
   *
   * \code
   *                ______                              _
   *               / _____)             _              | |
   *              ( (____  _____ ____ _| |_ _____  ____| |__
   *               \____ \| ___ |    (_   _) ___ |/ ___)  _ \
   *               _____) ) ____| | | || |_| ____( (___| | | |
   *              (______/|_____)_|_|_| \__)_____)\____)_| |_|
   *              (C)2013 Semtech
   *
   *               ___ _____ _   ___ _  _____ ___  ___  ___ ___
   *              / __|_   _/_\ / __| |/ / __/ _ \| _ \/ __| __|
   *              \__ \ | |/ _ \ (__| ' <| _| (_) |   / (__| _|
   *              |___/ |_/_/ \_\___|_|\_\_| \___/|_|_\\___|___|
   *              embedded.connectivity.solutions===============
   *
   * \endcode
   *
   * \author    Miguel Luis ( Semtech )
   *
   * \author    Gregory Cristian ( Semtech )
   *
   * \author    Daniel Jaeckle ( STACKFORCE )
   *
   * \defgroup  LORAMAC LoRa MAC layer implementation
   *            This module specifies the API implementation of the LoRaMAC layer.
   *            This is a placeholder for a detailed description of the LoRaMac
   *            layer and the supported features.
   *
   * Copyright (c) 2017, Arm Limited and affiliates.
   * SPDX-License-Identifier: BSD-3-Clause
   *
   */
  #ifndef MBED_LORAWAN_MAC_H__
  #define MBED_LORAWAN_MAC_H__
  
  #include "events/EventQueue.h"
  
  #include "lorastack/phy/LoRaPHY.h"
  
  #include "system/LoRaWANTimer.h"
  #include "system/lorawan_data_structures.h"
  
  #include "LoRaMacChannelPlan.h"
  #include "LoRaMacCommand.h"
  #include "LoRaMacCrypto.h"
  #if MBED_CONF_RTOS_PRESENT
  #include "rtos/Mutex.h"
  #endif
  
  #include "platform/ScopedLock.h"
  
  /** LoRaMac Class
   * Implementation of LoRaWAN MAC layer
   */
  class LoRaMac {
  
  public:
  
      /**
       * Constructor
       */
      LoRaMac();
  
      /**
       * Destructor
       */
      ~LoRaMac();
  
      /**
       * @brief   LoRaMAC layer initialization
       *
       * @details Initializes the LoRaMAC layer,
       *
       *
       * @param   queue [in]        A pointer to the application provided EventQueue.
       *
       * @param   scheduling_failure_handler    A callback to inform upper layer if a deferred
       *                                        transmission (after backoff or retry) fails to schedule.
       *
       * @return  `lorawan_status_t` The status of the operation. The possible values are:
       *          \ref LORAWAN_STATUS_OK
       *          \ref LORAWAN_STATUS_PARAMETER_INVALID
       */
      lorawan_status_t initialize(events::EventQueue *queue,
                                  mbed::Callback<void(void)>scheduling_failure_handler);
  
      /**
       * @brief   Disconnect LoRaMac layer
       *
       * @details Cancels all outstanding requests and sets LoRaMac's
       *          internal state to idle.
       */
      void disconnect(void);
  
      /**
       * @brief nwk_joined Checks if device has joined to network
       * @return True if joined to network, false otherwise
       */
      bool nwk_joined();
  
      /**
       * @brief   Adds a channel plan to the system.
       *
       * @details Adds a whole channel plan or a single new channel if the plan
       *          contains only one channel and 'plan.nb_channels' is set to 1.
       *          Please note that this functionality is not available in all regions.
       *          Information on the allowed ranges is available at the
       *          LoRaWAN Regional Parameters V1.0.2rB.
       *
       * @param   plan [in]    A reference to application provided channel plan.
       *
       * @return  `lorawan_status_t` The status of the operation. The possible values are:
       *          \ref LORAWAN_STATUS_OK
       *          \ref LORAWAN_STATUS_BUSY
       *          \ref LORAWAN_STATUS_PARAMETER_INVALID
       */
      lorawan_status_t add_channel_plan(const lorawan_channelplan_t &plan);
  
      /**
       * @brief   Removes a channel plan from the system.
       *
       * @details Removes the whole active channel plan except the 'Default Channels'.
       *          Please note that this functionality is not available in all regions.
       *          Information on the allowed ranges is available at the
       *          LoRaWAN Regional Parameters V1.0.2rB.
       *
       * @return  `lorawan_status_t` The status of the operation. The possible values are:
       *          \ref LORAWAN_STATUS_OK
       *          \ref LORAWAN_STATUS_BUSY
       *          \ref LORAWAN_STATUS_PARAMETER_INVALID
       */
      lorawan_status_t remove_channel_plan();
  
      /**
       * @brief   Access active channel plan.
       *
       * @details Provides access to the current active channel plan.
       *
       * @param   plan [out]    A reference to application provided channel plan data
       *                        structure which will be filled in with active channel
       *                        plan.
       *
       * @return  `lorawan_status_t` The status of the operation. The possible values are:
       *          \ref LORAWAN_STATUS_OK
       *          \ref LORAWAN_STATUS_BUSY
       *          \ref LORAWAN_STATUS_PARAMETER_INVALID
       */
      lorawan_status_t get_channel_plan(lorawan_channelplan_t &plan);
  
      /**
       * @brief   Remove a given channel from the active plan.
       *
       * @details Deactivates the given channel.
       *
       * @param id    Id of the channel.
       *
       * @return  `lorawan_status_t` The status of the operation. The possible values are:
       *          \ref LORAWAN_STATUS_OK
       *          \ref LORAWAN_STATUS_BUSY
       *          \ref LORAWAN_STATUS_PARAMETER_INVALID
       */
      lorawan_status_t remove_single_channel(uint8_t id);
  
      /**
       * @brief   LoRaMAC multicast channel link service.
       *
       * @details Links a multicast channel into the linked list.
       *
       * @param [in] channel_param    The multicast channel parameters to link.
       *
       * @return  `lorawan_status_t` The  status of the operation. The possible values are:
       *          \ref LORAWAN_STATUS_OK
       *          \ref LORAWAN_STATUS_BUSY
       *          \ref LORAWAN_STATUS_PARAMETER_INVALID
       */
      lorawan_status_t multicast_channel_link(multicast_params_t *channel_param);
  
      /**
       * @brief   LoRaMAC multicast channel unlink service.
       *
       * @details Unlinks a multicast channel from the linked list.
       *
       * @param [in] channel_param    The multicast channel parameters to unlink.
       *
       * @return  `lorawan_status_t` The status of the operation. The possible values are:
       *          \ref LORAWAN_STATUS_OK
       *          \ref LORAWAN_STATUS_BUSY
       *          \ref LORAWAN_STATUS_PARAMETER_INVALID
       */
      lorawan_status_t multicast_channel_unlink(multicast_params_t *channel_param);
  
      /** Binds phy layer to MAC.
       *
       * @param phy   LoRaPHY object
       */
      void bind_phy(LoRaPHY &phy);
  
      /**
       * @brief Schedules the frame for sending.
       *
       * @details Prepares a full MAC frame and schedules it for physical
       *          transmission.
       *
       * @param [in] mac_hdr      MAC frame header field
       * @param [in] fport        Payload port
       * @param [in] fbuffer      MAC frame data buffer to be sent
       * @param [in] fbuffer_size MAC frame data buffer size
       *
       * @return status          Status of the operation. LORAWAN_STATUS_OK in case
       *                         of success and a negative error code in case of
       *                         failure.
       */
      lorawan_status_t send(loramac_mhdr_t *mac_hdr, const uint8_t fport,
                            const void *fbuffer, uint16_t fbuffer_size);
  
      /**
       * @brief get_default_tx_datarate Gets the default TX datarate
       * @return default TX datarate.
       */
      uint8_t get_default_tx_datarate();
  
      /**
       * @brief enable_adaptive_datarate Enables or disables adaptive datarate.
       * @param adr_enabled Flag indicating is adr enabled or disabled.
       */
      void enable_adaptive_datarate(bool adr_enabled);
  
      /** Sets up the data rate.
       *
       * `set_datarate()` first verifies whether the data rate given is valid or not.
       * If it is valid, the system sets the given data rate to the channel.
       *
       * @param data_rate   The intended data rate, for example DR_0 or DR_1.
       *                    Note that the macro DR_* can mean different
       *                    things in different regions.
       *
       * @return            LORAWAN_STATUS_OK if everything goes well, otherwise
       *                    a negative error code.
       */
      lorawan_status_t set_channel_data_rate(uint8_t data_rate);
  
      /**
       * @brief tx_ongoing Check whether a prepare is done or not.
       * @return True if prepare_ongoing_tx is called, false otherwise.
       */
      bool tx_ongoing();
  
      /**
       * @brief set_tx_ongoing Changes the ongoing status for prepared message.
       * @param ongoing The value indicating the status.
       */
      void set_tx_ongoing(bool ongoing);
  
      /**
       * @brief reset_ongoing_tx Resets _ongoing_tx_msg.
       * @param reset_pending If true resets pending size also.
       */
      void reset_ongoing_tx(bool reset_pending = false);
  
      /**
       * @brief prepare_ongoing_tx This will prepare (and override) ongoing_tx_msg.
       * @param port                          The application port number.
       *
       * @param data                          A pointer to the data being sent. The ownership of the
       *                                      buffer is not transferred.
       *
       * @param length                        The size of data in bytes.
       *
       * @param flags                         A flag used to determine what type of
       *                                      message is being sent.
       *
       * @param num_retries                   Number of retries for a confirmed type message
       *
       * @return The number of bytes prepared for sending.
       */
      int16_t prepare_ongoing_tx(const uint8_t port, const uint8_t *data,
                                 uint16_t length, uint8_t flags, uint8_t num_retries);
  
      /**
       * @brief send_ongoing_tx Sends the ongoing_tx_msg
       * @return LORAWAN_STATUS_OK or a negative error code on failure.
       */
      lorawan_status_t send_ongoing_tx(void);
  
      /**
       * @brief device_class Returns active device class
       * @return Device class in use.
       */
      device_class_t get_device_class() const;
  
      /**
       * @brief set_device_class Sets active device class.
       * @param device_class Device class to use.
       * @param rx2_would_be_closure_handler callback function to inform about
       *        would be closure of RX2 window
       */
      void set_device_class(const device_class_t &device_class,
                            mbed::Callback<void(void)>rx2_would_be_closure_handler);
  
      /**
       * @brief setup_link_check_request Adds link check request command
       * to be put on next outgoing message (when it fits)
       */
      void setup_link_check_request();
  
      /**
       * @brief prepare_join prepares arguments to be ready for join() call.
       * @param params Join parameters to use, if NULL, the default will be used.
       * @param is_otaa True if joining is to be done using OTAA, false for ABP.
       *
       * @return LORAWAN_STATUS_OK or a negative error code on failure.
       */
      lorawan_status_t prepare_join(const lorawan_connect_t *params, bool is_otaa);
  
      /**
       * @brief join Joins the network.
       * @param is_otaa True if joining is to be done using OTAA, false for ABP.
       * @return LORAWAN_STATUS_OK or a negative error code on failure.
       */
      lorawan_status_t join(bool is_otaa);
  
      /**
       * MAC operations upon successful transmission
       */
      void on_radio_tx_done(lorawan_time_t timestamp);
  
      /**
       * MAC operations upon reception
       */
      void on_radio_rx_done(const uint8_t *const payload, uint16_t size,
                            int16_t rssi, int8_t snr);
  
      /**
       * MAC operations upon transmission timeout
       */
      void on_radio_tx_timeout(void);
  
      /**
       * MAC operations upon empty reception slots
       *
       * @param is_timeout false when radio encountered an error
       *                   true when the an RX slot went empty
       *
       * @return current RX slot
       */
      void on_radio_rx_timeout(bool is_timeout);
  
      /**
       * Handles retransmissions of Join requests if an Accept
       * was not received.
       *
       * @returns true if a retry will be made
       */
      bool continue_joining_process(void);
  
      /**
       * Checks if the CONFIRMED data can be sent again or not.
       */
      bool continue_sending_process(void);
  
      /**
       * Read-only access to MAC primitive blocks
       */
      const loramac_mcps_confirm_t *get_mcps_confirmation() const;
      const loramac_mcps_indication_t *get_mcps_indication() const;
      const loramac_mlme_confirm_t *get_mlme_confirmation() const;
      const loramac_mlme_indication_t *get_mlme_indication() const;
  
      /**
       * Post processing steps in response to actions carried out
       * by controller layer and Mac
       */
      void post_process_mcps_req(void);
      void post_process_mcps_ind(void);
      void post_process_mlme_request(void);
      void post_process_mlme_ind(void);
  
      /**
       * Set battery level query callback
       */
      void set_batterylevel_callback(mbed::Callback<uint8_t(void)> battery_level);
  
      /**
       * Returns the event ID of backoff timer.
       */
      int get_backoff_timer_event_id(void);
  
      /**
       * Clears out the TX pipe by discarding any outgoing message if the backoff
       * timer is still running.
       */
      lorawan_status_t clear_tx_pipe(void);
  
      /**
       * Gets the current time
       */
      lorawan_time_t get_current_time(void);
  
      /**
       * Gets the current receive slot
       */
      rx_slot_t get_current_slot(void);
  
      /**
       * Indicates what level of QOS is set by network server. QOS level is set
       * in response to a LinkADRReq for UNCONFIRMED messages
       */
      uint8_t get_QOS_level(void);
  
      /**
       *Indicates level of QOS used for the previous outgoing message
       */
      uint8_t get_prev_QOS_level(void);
  
      /**
       * These locks trample through to the upper layers and make
       * the stack thread safe.
       */
  #if MBED_CONF_RTOS_PRESENT
      void lock(void)
      {
          _mutex.lock();
      }
      void unlock(void)
      {
          _mutex.unlock();
      }
  #else
      void lock(void) { }
      void unlock(void) { }
  #endif
  
  private:
      /**
       * @brief   Queries the LoRaMAC the maximum possible FRMPayload size to send.
       *          The LoRaMAC takes the scheduled MAC commands into account and returns
       *          corresponding value.
       *
       * @param   fopts_len     [in]    Number of mac commands in the queue pending.
       *
       * @return  Size of the biggest packet that can be sent.
       *          Please note that if the size of the MAC commands in the queue do
       *          not fit into the payload size on the related datarate, the LoRaMAC will
       *          omit the MAC commands.
       */
      uint8_t get_max_possible_tx_size(uint8_t fopts_len);
  
      /**
       * @brief set_nwk_joined This is used for ABP mode for which real joining does not happen
       * @param joined True if device has joined in network, false otherwise
       */
      void set_nwk_joined(bool joined);
  
      /**
       * @brief Configures the events to trigger an MLME-Indication with
       *        a MLME type of MLME_SCHEDULE_UPLINK.
       */
      void set_mlme_schedule_ul_indication(void);
  
      /**
       * @brief Resets MAC specific parameters to default
       */
      void reset_mac_parameters(void);
  
      /**
       * Handles a Join Accept frame
       */
      void handle_join_accept_frame(const uint8_t *payload, uint16_t size);
  
      /**
       * Handles data frames
       */
      void handle_data_frame(const uint8_t *payload,  uint16_t size, uint8_t ptr_pos,
                             uint8_t msg_type, int16_t rssi, int8_t snr);
  
      /**
       * Send a Join Request
       */
      lorawan_status_t send_join_request();
  
      /**
       * Handles retransmissions
       */
      lorawan_status_t handle_retransmission();
  
      /**
       * Checks if the frame is valid
       */
      void check_frame_size(uint16_t size);
  
      /**
       * Performs MIC
       */
      bool message_integrity_check(const uint8_t *payload, uint16_t size,
                                   uint8_t *ptr_pos, uint32_t address,
                                   uint32_t *downlink_counter, const uint8_t *nwk_skey);
  
      /**
       * Decrypts and extracts data and MAC commands from the received encrypted
       * payload
       */
      void extract_data_and_mac_commands(const uint8_t *payload, uint16_t size,
                                         uint8_t fopts_len, uint8_t *nwk_skey,
                                         uint8_t *app_skey, uint32_t address,
                                         uint32_t downlink_frame_counter,
                                         int16_t rssi, int8_t snr);
      /**
       * Decrypts and extracts MAC commands from the received encrypted
       * payload if there is no data
       */
      void extract_mac_commands_only(const uint8_t *payload, int8_t snr, uint8_t fopts_len);
  
      /**
       * Callback function to be executed when the DC backoff timer expires
       */
      void on_backoff_timer_expiry(void);
  
      /**
       * At the end of an RX1 window timer, an RX1 window is opened using this method.
       */
      void open_rx1_window(void);
  
      /**
       * At the end of an RX2 window timer, an RX2 window is opened using this method.
       */
      void open_rx2_window(void);
  
      /**
       * A method to retry a CONFIRMED message after a particular time period
       * (ACK_TIMEOUT = TIME_IN_MS) if the ack was not received
       */
      void on_ack_timeout_timer_event(void);
  
      /*!
       * \brief Check if the OnAckTimeoutTimer has do be disabled. If so, the
       *        function disables it.
       *
       * \param [in] node_ack_requested Set to true, if the node has requested an ACK
       * \param [in] dev_class The device class
       * \param [in] ack_received Set to true, if the node has received an ACK
       * \param [in] ack_timeout_retries_counter Retries counter for confirmed uplinks
       * \param [in] ack_timeout_retries Maximum retries for confirmed uplinks
       */
      void check_to_disable_ack_timeout(bool node_ack_requested,
                                        device_class_t dev_class,
                                        bool ack_received,
                                        uint8_t ack_timeout_retries_counter,
                                        uint8_t ack_timeout_retries);
  
      /**
       * Validates if the payload fits into the frame, taking the datarate
       * into account.
       *
       * Please Refer to chapter 4.3.2 of the LoRaWAN specification, v1.0.2
       */
      bool validate_payload_length(uint16_t length, int8_t datarate, uint8_t fopts_len);
  
      /**
       * Prepares MAC frame on the behest of send() API.
       */
      lorawan_status_t prepare_frame(loramac_mhdr_t *mac_hdr,
                                     loramac_frame_ctrl_t *fctrl, const uint8_t fport,
                                     const void *fbuffer, uint16_t fbuffer_size);
  
      /**
       * Schedules a transmission on the behest of send() API.
       */
      lorawan_status_t schedule_tx();
  
      /**
       * Calculates the back-off time for the band of a channel.
       * Takes in the last used channel id as a parameter.
       */
      void calculate_backOff(uint8_t channel_id);
  
      /**
       * Hands over the MAC frame to PHY layer.
       */
      lorawan_status_t send_frame_on_channel(uint8_t channel);
  
      /**
       * Resets MAC primitive blocks
       */
      void reset_mcps_confirmation(void);
      void reset_mlme_confirmation(void);
      void reset_mcps_indication(void);
  
      /**
       * @brief set_tx_continuous_wave Puts the system in continuous transmission mode
       * @param [in] channel A Channel to use
       * @param [in] datarate A datarate to use
       * @param [in] tx_power A RF output power to use
       * @param [in] max_eirp A maximum possible EIRP to use
       * @param [in] antenna_gain Antenna gain to use
       * @param [in] timeout Time in seconds while the radio is kept in continuous wave mode
       */
      void set_tx_continuous_wave(uint8_t channel, int8_t datarate, int8_t tx_power,
                                  float max_eirp, float antenna_gain, uint16_t timeout);
  
  private:
      typedef mbed::ScopedLock<LoRaMac> Lock;
  #if MBED_CONF_RTOS_PRESENT
      rtos::Mutex _mutex;
  #endif
  
      /**
       * Timer subsystem handle
       */
      LoRaWANTimeHandler _lora_time;
  
      /**
       * LoRa PHY layer object storage
       */
      LoRaPHY *_lora_phy;
  
      /**
       * MAC command handle
       */
      LoRaMacCommand _mac_commands;
  
      /**
       * Channel planning subsystem
       */
      LoRaMacChannelPlan _channel_plan;
  
      /**
       * Crypto handling subsystem
       */
      LoRaMacCrypto _lora_crypto;
  
      /**
       * Central MAC layer data storage
       */
      loramac_protocol_params _params;
  
      /**
       * EventQueue object storage
       */
      events::EventQueue *_ev_queue;
  
      /**
       * Class C doesn't timeout in RX2 window as it is a continuous window.
       * We use this callback to inform the LoRaWANStack controller that we did
       * not receive a downlink in a time equal to normal Class A type RX2
       * window timeout. This marks a 'would-be' closure for RX2, actual RX2 is
       * not closed. Mostly network servers will send right at the beginning of
       * RX2 window if they have something to send. So if we didn't receive anything
       * in the time period equal to would be RX2 delay (which is a function of
       * uplink message length and data rate), we will invoke this callback to let
       * the upper layer know.
       */
      mbed::Callback<void(void)> _rx2_would_be_closure_for_class_c;
  
      /**
       * Transmission is async, i.e., a call to schedule_tx() may be deferred to
       * a time after a certain back off. We use this callback to inform the
       * controller layer that a specific TX transaction failed to schedule after
       * backoff or retry.
       */
      mbed::Callback<void(void)> _scheduling_failure_handler;
  
      timer_event_t _rx2_closure_timer_for_class_c;
  
      /**
       * Structure to hold MCPS indication data.
       */
      loramac_mcps_indication_t _mcps_indication;
  
      /**
       * Structure to hold MCPS confirm data.
       */
      loramac_mcps_confirm_t _mcps_confirmation;
  
      /**
       * Structure to hold MLME indication data.
       */
      loramac_mlme_indication_t _mlme_indication;
  
      /**
       * Structure to hold MLME confirm data.
       */
      loramac_mlme_confirm_t _mlme_confirmation;
  
      loramac_tx_message_t _ongoing_tx_msg;
  
      bool _is_nwk_joined;
  
      bool _can_cancel_tx;
  
      bool _continuous_rx2_window_open;
  
      device_class_t _device_class;
  
      uint8_t _prev_qos_level;
  
      bool _demod_ongoing;
  };
  
  #endif // MBED_LORAWAN_MAC_H__
  