CatM1: allow retry if connection fails

examples/ConnectionHandlerDemo/ConnectionHandlerDemo.ino

@@ -130,7 +130,53 @@ void loop() {
    * which might not guarantee the correct functioning of the ConnectionHandler
    * object.
    */
-  conMan.check();
+  if (conMan.check() != NetworkConnectionState::CONNECTED) {
+    return;
+  }
+
+#if !defined(BOARD_HAS_LORA)
+  Client &client = conMan.getClient();
+  /* arduino.tips */
+  IPAddress ip = IPAddress(104, 21, 62, 246);
+  int port = 80;
+
+  Serial.println("\nStarting connection to server...");
+  /* if you get a connection, report back via serial: */
+  if (!client.connect(ip, port)) {
+    Serial.println("unable to connect to server");
+    return;
+  }
+
+  Serial.println("connected to server");
+  /* Make a HTTP request: */
+  size_t w = client.println("GET /asciilogo.txt HTTP/1.1");
+  w += client.println("Host: arduino.tips");
+  w += client.println("User-Agent: Arduino");
+  w += client.println("Connection: close");
+  w += client.println();
+  Serial.print("Write size is ");
+  Serial.println(w);
+
+  /* if there are incoming bytes available  from the server,
+   * read them and print them:
+   */
+  while (client.connected()) {
+    size_t len = client.available();
+    if (len) {
+      uint8_t buff[len];
+      client.read(buff, len);
+      Serial.write(buff, len);
+    }
+    delay(0);
+  }
+
+  /* if the server's disconnected, stop the client: */
+  Serial.println();
+  Serial.println("disconnecting from server.");
+  client.stop();
+  delay(1000);
+#endif
+
 }
 
 void onNetworkConnect() {

src/CatM1ConnectionHandler.cpp

@@ -36,6 +36,7 @@ CatM1ConnectionHandler::CatM1ConnectionHandler(const char * pin, const char * ap
 , _pass(pass)
 , _rat(rat)
 , _band(band)
+, _reset(false)
 {
 
 }
@@ -46,7 +47,10 @@ CatM1ConnectionHandler::CatM1ConnectionHandler(const char * pin, const char * ap
 
 unsigned long CatM1ConnectionHandler::getTime()
 {
-  return GSM.getTime();
+  /* It is not safe to call GSM.getTime() since we don't know if modem internal
+   * RTC is in sync with current time.
+   */
+  return 0;
 }
 
 /******************************************************************************
@@ -56,28 +60,52 @@ unsigned long CatM1ConnectionHandler::getTime()
 NetworkConnectionState CatM1ConnectionHandler::update_handleInit()
 {
 #if defined (ARDUINO_EDGE_CONTROL)
+  /* Power on module */
   pinMode(ON_MKR2, OUTPUT);
   digitalWrite(ON_MKR2, HIGH);
 #endif
+
+  if(!GSM.begin(_pin, _apn, _login, _pass, _rat, _band, _reset))
+  {
+    Debug.print(DBG_ERROR, F("The board was not able to register to the network..."));
+    _reset = true;
+    return NetworkConnectionState::DISCONNECTED;
+  }
+  _reset = false;
   return NetworkConnectionState::CONNECTING;
 }
 
 NetworkConnectionState CatM1ConnectionHandler::update_handleConnecting()
 {
-  if(!GSM.begin(_pin, _apn, _login, _pass, _rat, _band))
+  int const is_gsm_access_alive = GSM.isConnected();
+  if (is_gsm_access_alive != 1)
   {
-    Debug.print(DBG_ERROR, F("The board was not able to register to the network..."));
-    return NetworkConnectionState::ERROR;
+    Debug.print(DBG_ERROR, F("GSM connection not alive... disconnecting"));
+    return NetworkConnectionState::DISCONNECTED;
+  }
+
+  Debug.print(DBG_INFO, F("Sending PING to outer space..."));
+  int const ping_result = GSM.ping("time.arduino.cc");
+  Debug.print(DBG_INFO, F("GSM.ping(): %d"), ping_result);
+  if (ping_result < 0)
+  {
+    Debug.print(DBG_ERROR, F("PING failed"));
+    Debug.print(DBG_INFO, F("Retrying in  \"%d\" milliseconds"), 2 * CHECK_INTERVAL_TABLE[static_cast<unsigned int>(NetworkConnectionState::CONNECTING)]);
+    return NetworkConnectionState::CONNECTING;
+  }
+  else
+  {
+    Debug.print(DBG_INFO, F("Connected to Network"));
+    return NetworkConnectionState::CONNECTED;
   }
-  Debug.print(DBG_INFO, F("Connected to Network"));
-  return NetworkConnectionState::CONNECTED;
 }
 
 NetworkConnectionState CatM1ConnectionHandler::update_handleConnected()
 {
   int const is_gsm_access_alive = GSM.isConnected();
   if (is_gsm_access_alive != 1)
   {
+    Debug.print(DBG_ERROR, F("GSM connection not alive... disconnecting"));
     return NetworkConnectionState::DISCONNECTED;
   }
   return NetworkConnectionState::CONNECTED;
@@ -91,6 +119,7 @@ NetworkConnectionState CatM1ConnectionHandler::update_handleDisconnecting()
 
 NetworkConnectionState CatM1ConnectionHandler::update_handleDisconnected()
 {
+  GSM.end();
   if (_keep_alive)
   {
     return NetworkConnectionState::INIT;

src/CatM1ConnectionHandler.h

@@ -66,6 +66,7 @@ class CatM1ConnectionHandler : public ConnectionHandler
 
     RadioAccessTechnologyType _rat;
     uint32_t _band;
+    bool _reset;
 
     GSMUDP _gsm_udp;
     GSMClient _gsm_client;