feat: add session restoration

src/lora.cpp

@@ -9,6 +9,7 @@ SX1276 radio = new Module(LORA_NSS, LORA_DIO0, LORA_RST, LORA_DIO1);
 LoRaWANNode node(&radio, &EU868);
 
 uint8_t noncesBuffer[RADIOLIB_LORAWAN_NONCES_BUF_SIZE];
+RTC_DATA_ATTR uint8_t LWsession[RADIOLIB_LORAWAN_SESSION_BUF_SIZE];
 
 void loraReset()
 {
@@ -24,7 +25,7 @@ void loraInit()
     loraReset();
     SPI.begin(LORA_SCK, LORA_MISO, LORA_MOSI, LORA_NSS);
 
-    Serial.print("[LoRa] Init... ");
+    Serial.print("[LoRaWAN] Init... ");
     int state = radio.begin();
     if (state != RADIOLIB_ERR_NONE)
     {
@@ -40,9 +41,7 @@ void loraInit()
 void loraRestoreDevNonce()
 {
     prefs.begin("lorawan");
-    size_t len = prefs.getBytesLength("nonces");
-
-    if (len == RADIOLIB_LORAWAN_NONCES_BUF_SIZE)
+    if (prefs.isKey("nonces"))
     {
         prefs.getBytes("nonces", noncesBuffer, RADIOLIB_LORAWAN_NONCES_BUF_SIZE);
     }
@@ -68,24 +67,62 @@ void loraPersistDevNonce()
     prefs.end();
 }
 
-void loraJoin()
+int16_t loraRestoreSession()
+{
+    Serial.print("[LoRaWAN] Tentative de restaurer la session...");
+
+    int16_t state = node.setBufferSession(LWsession);
+    if (state == RADIOLIB_ERR_NONE)
+    {
+        state = node.activateOTAA();
+    }
+    else {
+        Serial.println("Echec");
+    }
+    return state;
+}
+
+void loraSaveSession()
+{
+    uint8_t *session = node.getBufferSession();
+    memcpy(LWsession, session, RADIOLIB_LORAWAN_SESSION_BUF_SIZE);
+    Serial.println("[RTC] Session sauvegardée");
+}
+
+int16_t loraFullJoin()
 {
     node.beginOTAA(joinEUI, devEUI, nwkKey, appKey);
     loraRestoreDevNonce();
 
-    Serial.print("[LoRaWAN] Join... ");
-    int state = node.activateOTAA();
+    int16_t state = node.activateOTAA();
+
     loraPersistDevNonce();
-    if (state != RADIOLIB_LORAWAN_NEW_SESSION)
+    return state;
+}
+
+void loraJoin()
+{
+    int16_t state = RADIOLIB_ERR_NETWORK_NOT_JOINED;
+
+    node.beginOTAA(joinEUI, devEUI, nwkKey, appKey);
+    loraRestoreDevNonce();
+    if (loraRestoreSession() != RADIOLIB_LORAWAN_SESSION_RESTORED)
     {
-        Serial.printf("Echec : %d\n", state);
-        while (true)
+        Serial.print("[LoRaWAN] Join complet...");
+        int16_t state = loraFullJoin();
+
+        if (state != RADIOLIB_LORAWAN_NEW_SESSION)
         {
-            delay(1000);
+            Serial.printf("Echec : %d\n", state);
+            while (true)
+            {
+                delay(1000);
+            }
         }
     }
 
-    Serial.println("Join OK !");
+    Serial.println("OK");
+    loraSaveSession();
 }
 
 void loraSend(uint8_t payload[], size_t size)
@@ -99,4 +136,5 @@ void loraSend(uint8_t payload[], size_t size)
     {
         Serial.printf("[TX] Erreur : %d\n", state);
     }
+    loraSaveSession();
 }

src/lora.h

@@ -9,5 +9,7 @@ void loraJoin();
 void loraSend(uint8_t payload[], size_t size);
 void loraPersistDevNonce();
 void loraSaveDevNonce();
+void loraRestoreSession();
+void loraSaveSession();
 
 #endif

src/main.cpp

@@ -6,10 +6,11 @@ void setup() {
     
     loraInit();
     loraJoin();
+    uint8_t payload[] = { 0x01, 0x02, 0x03 };
+    loraSend(payload, sizeof(payload));
+    Serial.flush();
+    esp_deep_sleep(60000000);
 }
 
 void loop() {
-    uint8_t payload[] = { 0x01, 0x02, 0x03 };
-    loraSend(payload, sizeof(payload));
-    delay(60000);
 }