Streamlining connect() API with posix like retcodes

For ABP: First call to connect() or connect(params) will return LORAWAN_STATUS_OK
         and a CONNECTED event will be sent. Any subsequent call will return
         LORAWAN_STATUS_ALREADY_CONNECTED (posix EISCONN) and no event is generated.

FOR OTAA: First call to connect() or connect(params) will return LORAWAN_STATUS_CONNECT_IN_PROGRESS
          and a CONNECTED event will be sent whenever the JoinAccept is received. If the application
          calls connect again before receiving the CONNECTED event, LORAWAN_STATUS_BUSY will be returned.
          After the CONNECTED event is dispatched, any subsequent call to connect() or connect(params) API
          will be returned with LORWAN_STATUS_ALREADY_CONNECTED.

No new parameters are accepted after the first call. The application must disconnect before making
a connect() call with new parameters.

Author: Hasnain Virk

features/lorawan/LoRaWANBase.h

@@ -41,14 +41,14 @@ class LoRaWANBase {
      * Connect by Over The Air Activation or Activation By Personalization.
      * The connection type is selected at the setup.
      *
-     * @return         For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
-     *                           a 'CONNECTED' event. Otherwise a negative error code.
-     *                           Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
-     *
-     *                 For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned followed by
-     *                           a 'CONNECTED' event when the JoinAccept is received. Otherwise a negative error code
-     *                           is returned. Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no
-     *                           event follows.
+     * @return    For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
+     *                      a 'CONNECTED' event. Otherwise a negative error code is returned.
+     *                      Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
+     *
+     *            For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned for the first call.
+     *                      Any subsequent call will return either LORAWAN_STATUS_BUSY (if the previous request for connection
+     *                      is still underway) or LORAWAN_STATUS_ALREADY_CONNECTED (if a network was already joined successfully).
+     *                      A 'CONNECTED' event is sent to the application when the JoinAccept is received.
      */
     virtual lorawan_status_t connect() = 0;
 
@@ -60,14 +60,14 @@ class LoRaWANBase {
      *
      * @param connect       Options how end-device will connect to gateway
      *
-     * @return         For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
-     *                           a 'CONNECTED' event. Otherwise a negative error code.
-     *                           Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
+     * @return    For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
+     *                      a 'CONNECTED' event. Otherwise a negative error code is returned.
+     *                      Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
      *
-     *                 For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned followed by
-     *                           a 'CONNECTED' event when the JoinAccept is received. Otherwise a negative error code
-     *                           is returned. Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no
-     *                           event follows.
+     *            For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned for the first call.
+     *                      Any subsequent call will return either LORAWAN_STATUS_BUSY (if the previous request for connection
+     *                      is still underway) or LORAWAN_STATUS_ALREADY_CONNECTED (if a network was already joined successfully).
+     *                      A 'CONNECTED' event is sent to the application when the JoinAccept is received.
      */
     virtual lorawan_status_t connect(const lorawan_connect_t &connect) = 0;
 

features/lorawan/LoRaWANInterface.h

@@ -79,14 +79,14 @@ class LoRaWANInterface: public LoRaWANBase {
      * is important, at least for ABP. That's why we try to restore frame counters from
      * session information after a disconnection.
      *
-     * @return         For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
-     *                           a 'CONNECTED' event. Otherwise a negative error code.
-     *                           Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
-     *
-     *                 For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned followed by
-     *                           a 'CONNECTED' event when the JoinAccept is received. Otherwise a negative error code
-     *                           is returned. Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no
-     *                           event follows.
+     * @return    For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
+     *                      a 'CONNECTED' event. Otherwise a negative error code is returned.
+     *                      Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
+     *
+     *            For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned for the first call.
+     *                      Any subsequent call will return either LORAWAN_STATUS_BUSY (if the previous request for connection
+     *                      is still underway) or LORAWAN_STATUS_ALREADY_CONNECTED (if a network was already joined successfully).
+     *                      A 'CONNECTED' event is sent to the application when the JoinAccept is received.
      */
     virtual lorawan_status_t connect();
 
@@ -124,14 +124,14 @@ class LoRaWANInterface: public LoRaWANBase {
      *
      * @param connect  Options for an end device connection to the gateway.
      *
-     * @return         For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
-     *                           a 'CONNECTED' event. Otherwise a negative error code.
-     *                           Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
+     * @return    For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
+     *                      a 'CONNECTED' event. Otherwise a negative error code is returned.
+     *                      Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
      *
-     *                 For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned followed by
-     *                           a 'CONNECTED' event when the JoinAccept is received. Otherwise a negative error code
-     *                           is returned. Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no
-     *                           event follows.
+     *            For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned for the first call.
+     *                      Any subsequent call will return either LORAWAN_STATUS_BUSY (if the previous request for connection
+     *                      is still underway) or LORAWAN_STATUS_ALREADY_CONNECTED (if a network was already joined successfully).
+     *                      A 'CONNECTED' event is sent to the application when the JoinAccept is received.
      */
     virtual lorawan_status_t connect(const lorawan_connect_t &connect);
 

features/lorawan/LoRaWANStack.cpp

@@ -44,6 +44,7 @@ SPDX-License-Identifier: BSD-3-Clause
 #define CONNECTED_FLAG              0x00000004
 #define USING_OTAA_FLAG             0x00000008
 #define TX_DONE_FLAG                0x00000010
+#define CONN_IN_PROGRESS_FLAG       0x00000020
 
 using namespace mbed;
 using namespace events;
@@ -155,7 +156,11 @@ lorawan_status_t LoRaWANStack::connect()
         return LORAWAN_STATUS_NOT_INITIALIZED;
     }
 
-    if (_loramac.nwk_joined()) {
+    if (_ctrl_flags & CONN_IN_PROGRESS_FLAG) {
+        return LORAWAN_STATUS_BUSY;
+    }
+
+    if (_ctrl_flags & CONNECTED_FLAG) {
         return LORAWAN_STATUS_ALREADY_CONNECTED;
     }
 
@@ -174,7 +179,11 @@ lorawan_status_t LoRaWANStack::connect(const lorawan_connect_t &connect)
         return LORAWAN_STATUS_NOT_INITIALIZED;
     }
 
-    if (_loramac.nwk_joined()) {
+    if (_ctrl_flags & CONN_IN_PROGRESS_FLAG) {
+        return LORAWAN_STATUS_BUSY;
+    }
+
+    if (_ctrl_flags & CONNECTED_FLAG) {
         return LORAWAN_STATUS_ALREADY_CONNECTED;
     }
 
@@ -832,6 +841,8 @@ int LoRaWANStack::convert_to_msg_flag(const mcps_type_t type)
 
 lorawan_status_t LoRaWANStack::handle_connect(bool is_otaa)
 {
+    _ctrl_flags |= CONN_IN_PROGRESS_FLAG;
+
     if (is_otaa) {
         tr_debug("Initiating OTAA");
 
@@ -1157,30 +1168,23 @@ void LoRaWANStack::process_joining_state(lorawan_status_t &op_status)
 
 void LoRaWANStack::process_connected_state()
 {
+    _ctrl_flags |= CONNECTED_FLAG;
+    _ctrl_flags &= ~CONN_IN_PROGRESS_FLAG;
+
     if (_ctrl_flags & USING_OTAA_FLAG) {
         tr_debug("OTAA Connection OK!");
     }
 
     _lw_session.active = true;
     send_event_to_application(CONNECTED);
-    _ctrl_flags |= CONNECTED_FLAG;
 
     _device_current_state = DEVICE_STATE_IDLE;
 }
 
 void LoRaWANStack::process_connecting_state(lorawan_status_t &op_status)
 {
-    if (_device_current_state != DEVICE_STATE_IDLE
-            && _device_current_state != DEVICE_STATE_SHUTDOWN) {
-        op_status = LORAWAN_STATUS_BUSY;
-        return;
-    }
-
-    if (_ctrl_flags & CONNECTED_FLAG) {
-        tr_debug("Already connected");
-        op_status = LORAWAN_STATUS_ALREADY_CONNECTED;
-        return;
-    }
+    MBED_ASSERT(_device_current_state == DEVICE_STATE_IDLE ||
+                _device_current_state == DEVICE_STATE_SHUTDOWN);
 
     _device_current_state = DEVICE_STATE_CONNECTING;
 

features/lorawan/LoRaWANStack.h

@@ -84,29 +84,29 @@ class LoRaWANStack: private mbed::NonCopyable<LoRaWANStack> {
 
     /** Connect OTAA or ABP using Mbed-OS config system
      *
-     * @return         For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
-     *                           a 'CONNECTED' event. Otherwise a negative error code.
-     *                           Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
+     * @return    For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
+     *                      a 'CONNECTED' event. Otherwise a negative error code is returned.
+     *                      Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
      *
-     *                 For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned followed by
-     *                           a 'CONNECTED' event when the JoinAccept is received. Otherwise a negative error code
-     *                           is returned. Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no
-     *                           event follows.
+     *            For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned for the first call.
+     *                      Any subsequent call will return either LORAWAN_STATUS_BUSY (if the previous request for connection
+     *                      is still underway) or LORAWAN_STATUS_ALREADY_CONNECTED (if a network was already joined successfully).
+     *                      A 'CONNECTED' event is sent to the application when the JoinAccept is received.
      */
     lorawan_status_t connect();
 
     /** Connect OTAA or ABP with parameters
      *
      * @param connect  Options for an end device connection to the gateway.
      *
-     * @return         For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
-     *                           a 'CONNECTED' event. Otherwise a negative error code.
-     *                           Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
+     * @return    For ABP:  If everything goes well, LORAWAN_STATUS_OK is returned for first call followed by
+     *                      a 'CONNECTED' event. Otherwise a negative error code is returned.
+     *                      Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no event follows.
      *
-     *                 For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned followed by
-     *                           a 'CONNECTED' event when the JoinAccept is received. Otherwise a negative error code
-     *                           is returned. Any subsequent call will return LORAWAN_STATUS_ALREADY_CONNECTED and no
-     *                           event follows.
+     *            For OTAA: When a JoinRequest is sent, LORAWAN_STATUS_CONNECT_IN_PROGRESS is returned for the first call.
+     *                      Any subsequent call will return either LORAWAN_STATUS_BUSY (if the previous request for connection
+     *                      is still underway) or LORAWAN_STATUS_ALREADY_CONNECTED (if a network was already joined successfully).
+     *                      A 'CONNECTED' event is sent to the application when the JoinAccept is received.
      */
     lorawan_status_t connect(const lorawan_connect_t &connect);