Sesame-Device/include/storage.h
2023-08-09 13:13:38 +02:00

83 lines
2.2 KiB
C++

#pragma once
#include <stdint.h>
class Storage {
public:
Storage(uint8_t remoteDeviceCount) : remoteDeviceCount(remoteDeviceCount) { };
/**
* @brief Initialize the use of the message counter API
*
* The message counter is stored in EEPROM, which must be initialized before use.
*
* @note The ESP32 does not have a true EEPROM,
* which is emulated using a section of the flash memory.
*/
void configure();
/**
* @brief Check if a device ID is allowed
*
* @param deviceId The ID to check
* @return true The id is valid
* @return false The id is invalid
*/
bool isDeviceIdValid(uint8_t deviceId);
/**
* @brief Check if a received counter is valid
*
* The counter is valid if it is larger than the previous counter
* (larger or equal to the next expected counter).
*
* @param counter The counter to check
* @return true The counter is valid
* @return false The counter belongs to an old message
*/
bool isMessageCounterValid(uint32_t counter, uint8_t deviceId);
/**
* @brief Mark a counter of a message as used.
*
* The counter value is stored in EEPROM to persist across restarts.
*
* All messages with counters lower than the given one will become invalid.
*
* @param counter The counter used in the last message.
*/
void didUseMessageCounter(uint32_t counter, uint8_t deviceId);
/**
* @brief Get the expected count for the next message.
*
* The counter is stored in EEPROM to persist across restarts
*
* @return The next counter to use by the remote
*/
uint32_t getNextMessageCounter(uint8_t deviceId);
/**
* @brief Print info about the current message counter to the serial output
*
*/
void printMessageCounters();
/**
* @brief Reset the message counter.
*
* @warning The counter should never be reset in production environments,
* and only together with a new secret key. Otherwise old messages may be
* used for replay attacks.
*
*/
void resetMessageCounters();
private:
uint8_t remoteDeviceCount;
void setMessageCounter(uint32_t counter, uint8_t deviceId);
};