LoRaWAN: Handling re-joining when already Joined

This is a remedy for the issue #7230.
While the device is joining, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned.
However, if the device is already joined, we will return LORAWAN_STATUS_ALREADY_CONNECTED.

Author: Hasnain Virk

features/lorawan/LoRaWANStack.cpp

@@ -155,6 +155,10 @@ lorawan_status_t LoRaWANStack::connect()
         return LORAWAN_STATUS_NOT_INITIALIZED;
     }
 
+    if (_loramac.nwk_joined()) {
+        return LORAWAN_STATUS_ALREADY_CONNECTED;
+    }
+
     lorawan_status_t status = _loramac.prepare_join(NULL, MBED_CONF_LORA_OVER_THE_AIR_ACTIVATION);
 
     if (LORAWAN_STATUS_OK != status) {
@@ -170,6 +174,10 @@ lorawan_status_t LoRaWANStack::connect(const lorawan_connect_t &connect)
         return LORAWAN_STATUS_NOT_INITIALIZED;
     }
 
+    if (_loramac.nwk_joined()) {
+        return LORAWAN_STATUS_ALREADY_CONNECTED;
+    }
+
     if (!(connect.connect_type == LORAWAN_CONNECTION_OTAA)
             && !(connect.connect_type == LORAWAN_CONNECTION_ABP)) {
         return LORAWAN_STATUS_PARAMETER_INVALID;
@@ -1170,7 +1178,7 @@ void LoRaWANStack::process_connecting_state(lorawan_status_t &op_status)
 
     if (_ctrl_flags & CONNECTED_FLAG) {
         tr_debug("Already connected");
-        op_status = LORAWAN_STATUS_OK;
+        op_status = LORAWAN_STATUS_ALREADY_CONNECTED;
         return;
     }
 

features/lorawan/lorastack/mac/LoRaMac.cpp

@@ -814,9 +814,11 @@ lorawan_status_t LoRaMac::send_join_request()
     status = prepare_frame(&mac_hdr, &fctrl, 0, NULL, 0);
 
     if (status == LORAWAN_STATUS_OK) {
-        status = schedule_tx();
+        if (schedule_tx() == LORAWAN_STATUS_OK) {
+            status = LORAWAN_STATUS_CONNECT_IN_PROGRESS;
+        }
     } else {
-        tr_error("Retransmission: error %d", status);
+        tr_error("Couldn't send a JoinRequest: error %d", status);
     }
 
     return status;

features/lorawan/lorawan_types.h

@@ -98,10 +98,11 @@ typedef enum lorawan_status {
 #if defined(LORAWAN_COMPLIANCE_TEST)
     LORAWAN_STATUS_COMPLIANCE_TEST_ON = -1019,     /**< Compliance test - is on-going */
 #endif
-    LORAWAN_STATUS_DUTYCYCLE_RESTRICTED = -1020,
-    LORAWAN_STATUS_NO_CHANNEL_FOUND = -1021,
-    LORAWAN_STATUS_NO_FREE_CHANNEL_FOUND = -1022,
-    LORAWAN_STATUS_METADATA_NOT_AVAILABLE = -1023
+    LORAWAN_STATUS_DUTYCYCLE_RESTRICTED = -1020,   /**< Transmission will continue after duty cycle backoff*/
+    LORAWAN_STATUS_NO_CHANNEL_FOUND = -1021,       /**< None of the channels is enabled at the moment*/
+    LORAWAN_STATUS_NO_FREE_CHANNEL_FOUND = -1022,  /**< None of the enabled channels is ready for another TX (duty cycle limited)*/
+    LORAWAN_STATUS_METADATA_NOT_AVAILABLE = -1023, /**< Meta-data after an RX or TX is stale*/
+    LORAWAN_STATUS_ALREADY_CONNECTED = -1024              /**< The device has already joined a network*/
 } lorawan_status_t;
 
 /** The lorawan_connect_otaa structure.