Making cancel_sending() API robust

features/lorawan/LoRaWANBase.h

@@ -493,6 +493,7 @@ class LoRaWANBase {
      *                      other negative error code if request failed:
      *                      LORAWAN_STATUS_NOT_INITIALIZED if system is not initialized with initialize(),
      *                      LORAWAN_STATUS_BUSY if the send cannot be canceled
+     *                      LORAWAN_STATUS_NO_OP if the operation cannot be completed (nothing to cancel)
      */
     virtual lorawan_status_t cancel_sending(void) = 0;
 };

features/lorawan/LoRaWANStack.cpp

@@ -272,15 +272,17 @@ lorawan_status_t LoRaWANStack::stop_sending(void)
         return LORAWAN_STATUS_NOT_INITIALIZED;
     }
 
-    if (_loramac.clear_tx_pipe() == LORAWAN_STATUS_OK) {
+    lorawan_status_t status = _loramac.clear_tx_pipe();
+
+    if (status == LORAWAN_STATUS_OK) {
         _ctrl_flags &= ~TX_DONE_FLAG;
         _ctrl_flags &= ~TX_ONGOING_FLAG;
         _loramac.set_tx_ongoing(false);
         _device_current_state = DEVICE_STATE_IDLE;
         return LORAWAN_STATUS_OK;
     }
 
-    return LORAWAN_STATUS_BUSY;
+    return status;
 }
 
 int16_t LoRaWANStack::handle_tx(const uint8_t port, const uint8_t *data,
@@ -294,11 +296,6 @@ int16_t LoRaWANStack::handle_tx(const uint8_t port, const uint8_t *data,
     if (!null_allowed && !data) {
         return LORAWAN_STATUS_PARAMETER_INVALID;
     }
-    // add a link check request with normal data, until the application
-    // explicitly removes it.
-    if (_link_check_requested) {
-        _loramac.setup_link_check_request();
-    }
 
     if (!_lw_session.active) {
         return LORAWAN_STATUS_NO_ACTIVE_SESSIONS;
@@ -308,6 +305,12 @@ int16_t LoRaWANStack::handle_tx(const uint8_t port, const uint8_t *data,
         return LORAWAN_STATUS_WOULD_BLOCK;
     }
 
+    // add a link check request with normal data, until the application
+    // explicitly removes it.
+    if (_link_check_requested) {
+        _loramac.setup_link_check_request();
+    }
+
     lorawan_status_t status;
 
     if (_loramac.nwk_joined() == false) {

features/lorawan/lorastack/mac/LoRaMac.cpp

@@ -77,6 +77,7 @@ LoRaMac::LoRaMac()
       _mlme_indication(),
       _mlme_confirmation(),
       _is_nwk_joined(false),
+      _can_cancel_tx(true),
       _continuous_rx2_window_open(false),
       _device_class(CLASS_A)
 {
@@ -1030,11 +1031,16 @@ int LoRaMac::get_backoff_timer_event_id(void)
 
 lorawan_status_t LoRaMac::clear_tx_pipe(void)
 {
+    if (!_can_cancel_tx) {
+        return LORAWAN_STATUS_BUSY;
+    }
+
     // check if the event is not already queued
     const int id = get_backoff_timer_event_id();
+
     if (id == 0) {
         // No queued send request
-        return LORAWAN_STATUS_OK;
+        return LORAWAN_STATUS_NO_OP;
     }
 
     if (_ev_queue->time_left(id) > 0) {
@@ -1092,6 +1098,7 @@ lorawan_status_t LoRaMac::schedule_tx()
         case LORAWAN_STATUS_DUTYCYCLE_RESTRICTED:
             if (backoff_time != 0) {
                 tr_debug("DC enforced: Transmitting in %lu ms", backoff_time);
+                _can_cancel_tx = true;
                 _lora_time.start(_params.timers.backoff_timer, backoff_time);
             }
             return LORAWAN_STATUS_OK;
@@ -1154,6 +1161,7 @@ lorawan_status_t LoRaMac::schedule_tx()
         _params.is_srv_ack_requested = false;
     }
 
+    _can_cancel_tx = false;
     return send_frame_on_channel(_params.channel);
 }
 
@@ -1238,6 +1246,7 @@ bool LoRaMac::tx_ongoing()
 
 void LoRaMac::set_tx_ongoing(bool ongoing)
 {
+    _can_cancel_tx = true;
     _ongoing_tx_msg.tx_ongoing = ongoing;
 }
 

features/lorawan/lorastack/mac/LoRaMac.h

@@ -669,6 +669,8 @@ class LoRaMac {
 
     bool _is_nwk_joined;
 
+    bool _can_cancel_tx;
+
     bool _continuous_rx2_window_open;
 
     device_class_t _device_class;

features/lorawan/lorawan_types.h

@@ -98,13 +98,9 @@ typedef enum lorawan_status {
     LORAWAN_STATUS_CRYPTO_FAIL = -1014,            /**< Service not started - crypto failure */
     LORAWAN_STATUS_PORT_INVALID = -1015,           /**< Invalid port */
     LORAWAN_STATUS_CONNECT_IN_PROGRESS = -1016,    /**< Services started - Connection in progress */
-    LORAWAN_STATUS_NO_ACTIVE_SESSIONS = -1017,            /**< Services not started - No active session */
+    LORAWAN_STATUS_NO_ACTIVE_SESSIONS = -1017,     /**< Services not started - No active session */
     LORAWAN_STATUS_IDLE = -1018,                   /**< Services started - Idle at the moment */
-#if defined(LORAWAN_COMPLIANCE_TEST)
-    //Deprecated - will replace the code -1019 with something
-    //else in future.
-    LORAWAN_STATUS_COMPLIANCE_TEST_ON = -1019,     /**< Compliance test - is on-going */
-#endif
+    LORAWAN_STATUS_NO_OP = -1019,                  /**< Cannot perform requested operation */
     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)*/