Create storage class

include/controller.h

@@ -3,18 +3,22 @@
 #include "server.h"
 #include "servo.h"
 #include "message.h"
+#include "storage.h"
 #include <ESPAsyncWebServer.h>
 
 class SesameController: public ServerConnectionCallbacks {
 
 public:
-    SesameController(ServerConnection* server, ServoController* servo, AsyncWebServer* local);
+    SesameController(ServerConnection* server, ServoController* servo, AsyncWebServer* local, uint8_t remoteDeviceCount);
+
+    void configure();
 
 private:
 
     ServerConnection* server;
     ServoController* servo;
     AsyncWebServer* local;
+    Storage storage;
 
     // The buffer to hold a received message while it is read
     uint8_t receivedMessageBuffer[AUTHENTICATED_MESSAGE_SIZE];
@@ -37,6 +41,5 @@ private:
 
     uint16_t prepareResponseBuffer(SesameEvent event, uint8_t deviceId = 0);
     void sendPreparedLocalResponse(AsyncWebServerRequest *request);
-    void sendLocalResponse(AsyncWebServerRequest *request, SesameEvent event, uint8_t deviceId = 0);
     void sendPreparedServerResponse();
 };

include/fresh.h

@@ -3,11 +3,6 @@
 #include <stdint.h>
 #include "config.h"
 
-/**
- * @brief The size of the message counter in bytes (uint32_t)
- */
-#define MESSAGE_COUNTER_SIZE sizeof(uint32_t)
-
 /**
  * @brief Configure an NTP server to get the current time
  * 
@@ -55,63 +50,3 @@ void setMessageTimeAllowedOffset(uint32_t offset);
  * @return false The message time is invalid
  */
 bool isMessageTimeAcceptable(uint32_t messageTime);
-
-/**
- * @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 prepareMessageCounterUsage();
-
-/**
- * @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();
-
-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 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();

include/message.h

@@ -53,6 +53,8 @@ typedef struct {
 
 } Message;
 
+constexpr size_t messageCounterSize = sizeof(uint32_t);
+
 /**
  * @brief An authenticated message by the mobile device to command unlocking.
  * 

include/storage.h

@@ -0,0 +1,83 @@
+#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);
+};

src/controller.cpp

@@ -3,11 +3,17 @@
 #include "fresh.h"
 #include "crypto.h"
 
-SesameController::SesameController(ServerConnection* server, ServoController* servo, AsyncWebServer* local) : 
+SesameController::SesameController(ServerConnection* server, ServoController* servo, AsyncWebServer* local, uint8_t remoteDeviceCount) : 
-server(server), servo(servo), local(local) {
+    server(server), servo(servo), local(local), storage(remoteDeviceCount) {
+    
     // Set up response buffer
     responseStatus = (SesameEvent*) responseBuffer;
     responseMessage = (AuthenticatedMessage*) (responseBuffer + 1);
+}
+
+void SesameController::configure() {
+    // Prepare EEPROM for reading and writing
+    storage.configure();
     
     // Direct messages and errors over the websocket to the controller
     server->setCallbackHandler(this);
@@ -17,6 +23,9 @@ server(server), servo(servo), local(local) {
         this->handleLocalMessage(request); 
         this->sendPreparedLocalResponse(request);
     });
+
+    //storage.resetMessageCounters();
+    storage.printMessageCounters();
 }
 
 // MARK: Local
@@ -84,17 +93,17 @@ SesameEvent SesameController::verifyAndProcessReceivedMessage(AuthenticatedMessa
     if (!isAuthenticMessage(message, remoteKey, keySize)) {
         return SesameEvent::MessageAuthenticationFailed;
     }
-    if (!isDeviceIdValid(message->message.device)) {
+    if (!storage.isDeviceIdValid(message->message.device)) {
         return SesameEvent::MessageDeviceInvalid;
     }
-    if (!isMessageCounterValid(message->message.id, message->message.device)) {
+    if (!storage.isMessageCounterValid(message->message.id, message->message.device)) {
         return SesameEvent::MessageCounterInvalid;
     }
     if (!isMessageTimeAcceptable(message->message.time)) {
         return SesameEvent::MessageTimeMismatch;
     }
 
-    didUseMessageCounter(message->message.id, message->message.device);
+    storage.didUseMessageCounter(message->message.id, message->message.device);
     // Move servo
     servo->pressButton();
     Serial.printf("[Info] Accepted message %d\n", message->message.id);
@@ -119,7 +128,7 @@ uint16_t SesameController::prepareResponseBuffer(SesameEvent event, uint8_t devi
         return 1;
     }
     responseMessage->message.time = getEpochTime();
-    responseMessage->message.id = getNextMessageCounter(deviceId);
+    responseMessage->message.id = storage.getNextMessageCounter(deviceId);
     responseMessage->message.device = deviceId;
     if (!authenticateMessage(responseMessage, localKey, keySize)) {
         *responseStatus = SesameEvent::InvalidResponseAuthentication;

src/fresh.cpp

@@ -2,7 +2,6 @@
 
 #include <Arduino.h>
 #include <time.h>
-#include <EEPROM.h>
 
 /**
  * @brief The allowed discrepancy between the time of a received message
@@ -56,53 +55,3 @@ bool isMessageTimeAcceptable(uint32_t t) {
     }
     return true;
 }
-
-void prepareMessageCounterUsage() {
-    EEPROM.begin(MESSAGE_COUNTER_SIZE * remoteDeviceCount);
-}
-
-uint32_t getNextMessageCounter(uint8_t deviceId) {
-    int offset = deviceId * MESSAGE_COUNTER_SIZE;
-    uint32_t counter = (uint32_t) EEPROM.read(offset + 0) << 24;
-    counter         += (uint32_t) EEPROM.read(offset + 1) << 16;
-    counter         += (uint32_t) EEPROM.read(offset + 2) << 8;
-    counter         += (uint32_t) EEPROM.read(offset + 3);
-    return counter;
-}
-
-void printMessageCounters() {
-    Serial.print("[INFO] Next message numbers:");
-    for (uint8_t i = 0; i < remoteDeviceCount; i += 1) {
-        Serial.printf(" %u", getNextMessageCounter(i));
-    }
-    Serial.println("");
-}
-
-bool isDeviceIdValid(uint8_t deviceId) {
-    return deviceId < remoteDeviceCount;
-}
-
-bool isMessageCounterValid(uint32_t counter, uint8_t deviceId) {
-    return counter >= getNextMessageCounter(deviceId);
-}
-
-void setMessageCounter(uint32_t counter, uint8_t deviceId) {
-    int offset = deviceId * MESSAGE_COUNTER_SIZE;
-    EEPROM.write(offset + 0, (counter >> 24) & 0xFF);
-    EEPROM.write(offset + 1, (counter >> 16) & 0xFF);
-    EEPROM.write(offset + 2, (counter >>  8) & 0xFF);
-    EEPROM.write(offset + 3,  counter        & 0xFF);
-    EEPROM.commit();
-}
-
-void didUseMessageCounter(uint32_t counter, uint8_t deviceId) {
-    // Store the next counter, so that resetting starts at 0
-    setMessageCounter(counter+1, deviceId);
-}
-
-void resetMessageCounters() {
-    for (uint8_t i = 0; i < remoteDeviceCount; i += 1) {
-        setMessageCounter(0, i);
-    }
-    Serial.println("[WARN] Message counters reset");
-}

src/main.cpp

@@ -25,7 +25,7 @@ ServoController servo(pwmTimer, servoFrequency, servoPin);
 
 AsyncWebServer local(localPort);
 
-SesameController controller(&server, &servo, &local);
+SesameController controller(&server, &servo, &local, remoteDeviceCount);
 
 // Forward declare monitoring functions
 void ensureWiFiConnection(uint32_t time);
@@ -41,9 +41,7 @@ void setup() {
     servo.configure(lockOpeningDuration, servoPressedState, servoReleasedState);
     Serial.println("[INFO] Servo configured");
 
-    prepareMessageCounterUsage();
+    controller.configure();
-    //resetMessageCounters();
-    printMessageCounters();
 }
 
 void loop() {

src/storage.cpp

@@ -0,0 +1,53 @@
+#include "storage.h"
+#include "message.h"
+#include <EEPROM.h>
+
+void Storage::configure() {
+    EEPROM.begin(messageCounterSize * remoteDeviceCount);
+}
+
+bool Storage::isDeviceIdValid(uint8_t deviceId) {
+    return deviceId < remoteDeviceCount;
+}
+
+bool Storage::isMessageCounterValid(uint32_t counter, uint8_t deviceId) {
+    return counter >= getNextMessageCounter(deviceId);
+}
+
+void Storage::didUseMessageCounter(uint32_t counter, uint8_t deviceId) {
+    // Store the next counter, so that resetting starts at 0
+    setMessageCounter(counter+1, deviceId);
+}
+
+void Storage::setMessageCounter(uint32_t counter, uint8_t deviceId) {
+    int offset = deviceId * messageCounterSize;
+    EEPROM.write(offset + 0, (counter >> 24) & 0xFF);
+    EEPROM.write(offset + 1, (counter >> 16) & 0xFF);
+    EEPROM.write(offset + 2, (counter >>  8) & 0xFF);
+    EEPROM.write(offset + 3,  counter        & 0xFF);
+    EEPROM.commit();
+}
+
+uint32_t Storage::getNextMessageCounter(uint8_t deviceId) {
+    int offset = deviceId * messageCounterSize;
+    uint32_t counter = (uint32_t) EEPROM.read(offset + 0) << 24;
+    counter         += (uint32_t) EEPROM.read(offset + 1) << 16;
+    counter         += (uint32_t) EEPROM.read(offset + 2) << 8;
+    counter         += (uint32_t) EEPROM.read(offset + 3);
+    return counter;
+}
+
+void Storage::printMessageCounters() {
+    Serial.print("[INFO] Next message numbers:");
+    for (uint8_t i = 0; i < remoteDeviceCount; i += 1) {
+        Serial.printf(" %u", getNextMessageCounter(i));
+    }
+    Serial.println("");
+}
+
+void Storage::resetMessageCounters() {
+    for (uint8_t i = 0; i < remoteDeviceCount; i += 1) {
+        setMessageCounter(0, i);
+    }
+    Serial.println("[WARN] Message counters reset");
+}