Remove recursion from MAC layer (ARMmbed#1826)

Failing MCPS write request is calling callback function directly and
a caller would then trigger a new MCPS write request. This recursion
can cause stack overflow in some conditions.

Change failing data request to use event queue when returning status
back to caller.

Author: Arto Kinnunen

source/MAC/IEEE802_15_4/mac_defines.h

@@ -39,6 +39,7 @@ typedef enum mac_event_t {
     MAC_TX_FAIL,
     MAC_TX_TIMEOUT,
     MAC_UNKNOWN_DESTINATION,
+    MAC_TX_PRECOND_FAIL
 } mac_event_t;
 
 typedef enum mac_tx_status_type_t {

source/MAC/IEEE802_15_4/mac_mcps_sap.c

@@ -145,7 +145,6 @@ static void mac_data_poll_radio_disable_check(protocol_interface_rf_mac_setup_s
 
 static void mcps_data_confirm_cb(protocol_interface_rf_mac_setup_s *rf_mac_setup, mcps_data_conf_t *confirm, mac_pre_parsed_frame_t *ack_buf)
 {
-
     mac_data_poll_radio_disable_check(rf_mac_setup);
 
     if( get_sw_mac_api(rf_mac_setup) ) {
@@ -1123,8 +1122,8 @@ static int8_t mac_ack_sap_rx_handler(mac_pre_parsed_frame_t *buf, protocol_inter
     return 0;
 }
 
-static void mac_pd_data_confirm_handle(protocol_interface_rf_mac_setup_s *rf_mac_setup) {
-
+static void mac_pd_data_confirm_handle(protocol_interface_rf_mac_setup_s *rf_mac_setup)
+{
     if (rf_mac_setup->active_pd_data_request) {
         mac_pre_build_frame_t *buffer = rf_mac_setup->active_pd_data_request;
         if (mac_data_request_confirmation_finnish(rf_mac_setup, buffer) ) {
@@ -1146,8 +1145,8 @@ static void mac_pd_data_confirm_handle(protocol_interface_rf_mac_setup_s *rf_mac
 }
 
 
-static void mac_pd_data_ack_handler(mac_pre_parsed_frame_t *buf) {
-
+static void mac_pd_data_ack_handler(mac_pre_parsed_frame_t *buf)
+{
     protocol_interface_rf_mac_setup_s *rf_mac_setup = buf->mac_class_ptr;
 
     if (!rf_mac_setup->active_pd_data_request) {
@@ -1357,7 +1356,9 @@ static void mac_common_data_confirmation_handle (protocol_interface_rf_mac_setup
             buf->status = MLME_TRANSACTION_EXPIRED;
         } else if (m_event == MAC_UNKNOWN_DESTINATION) {
             buf->status = MLME_UNAVAILABLE_KEY;
-        }
+        }/** else if (m_event == MAC_TX_PRECOND_FAIL) {
+           * Nothing to do, status already set to buf->status.
+        }**/
     }
 }
 
@@ -1904,17 +1905,9 @@ void mcps_sap_pd_req_queue_write(protocol_interface_rf_mac_setup_s *rf_mac_setup
         //Start TX process immediately
         mac_data_request_init(rf_mac_setup, buffer);
         if (mcps_pd_data_request(rf_mac_setup, buffer) != 0) {
-            rf_mac_setup->active_pd_data_request = NULL;
-            mcps_data_conf_t confirm;
-            memset(&confirm, 0, sizeof(mcps_data_conf_t));
-            confirm.msduHandle = buffer->msduHandle;
-            confirm.status = buffer->status;
-            bool requested_from_up = buffer->upper_layer_request;
-            mcps_sap_prebuild_frame_buffer_free(buffer);
-            if (requested_from_up) {
-                mcps_data_confirm_cb(rf_mac_setup, &confirm, NULL);
-            }
-            //Call
+            rf_mac_setup->mac_tx_result = MAC_TX_PRECOND_FAIL;
+            rf_mac_setup->macTxRequestAck = false;
+            mcps_sap_pd_confirm(rf_mac_setup);
         }
 
         return;

test/nanostack/unittest/mac/mac_mcps_sap/test_mac_mcps_sap.c

@@ -2463,11 +2463,11 @@ bool test_mcps_sap_data_req_handler()
     nsdynmemlib_stub.returnCounter = 1;
     data_req.msduHandle = msdu_handle++;
     mcps_sap_data_req_handler(rf_mac_setup, &data_req);
-    if (rf_mac_setup->active_pd_data_request || !data_confirm_valid) {
+    /* async callback is not called, active_pd_data_request available in rf_mac_setup */
+    if (!rf_mac_setup->active_pd_data_request || data_confirm_valid) {
         return false;
     }
 
-
     //Test with unknow neighbor
     mac_security_mib_stub.key_ptr = &key_description;
 
@@ -2477,7 +2477,8 @@ bool test_mcps_sap_data_req_handler()
     data_req.TxAckReq = true;
     mcps_sap_data_req_handler(rf_mac_setup, &data_req);
     data_req.msduHandle = msdu_handle++;
-    if (rf_mac_setup->active_pd_data_request || !data_confirm_valid) {
+    /* async callback is not called, active_pd_data_request available in rf_mac_setup */
+    if (!rf_mac_setup->active_pd_data_request || data_confirm_valid) {
         return false;
     }