Delete transaction if message is non-confirmable (ARMmbed#83)

* Delete transaction if message is non-confirmable

* Delete transaction if message is non-confirmable

After transaction is sent, delete transaction pointer if no response callback
is defined and message type is non-confirmable

source/coap_message_handler.c

@@ -337,6 +337,7 @@ uint16_t coap_message_handler_request_send(coap_msg_handler_t *handle, int8_t se
     transaction_ptr->options = options;
     memcpy(transaction_ptr->remote_address, destination_addr, 16);
     transaction_ptr->remote_port = destination_port;
+    transaction_ptr->req_msg_type = msg_type;
     memset(&request, 0, sizeof(request));
     dst_addr.addr_ptr = (uint8_t *) destination_addr; // Cast away const and trust that nsdl doesn't modify...
     dst_addr.addr_len  =  16;

source/coap_service_api.c

@@ -188,7 +188,7 @@ static uint8_t coap_tx_function(uint8_t *data_ptr, uint16_t data_len, sn_nsdl_ad
             memcpy(transaction_ptr->data_ptr, data_ptr, data_len);
             transaction_ptr->data_len = data_len;
         }
-    } else if ((ret_val == -1) || (transaction_ptr->resp_cb == NULL)) {
+    } else if ((ret_val == -1) || (!transaction_ptr->resp_cb && transaction_ptr->req_msg_type == COAP_MSG_TYPE_NON_CONFIRMABLE)) {
         transaction_delete(transaction_ptr);
     }
 
@@ -300,7 +300,7 @@ static void sec_done_cb(int8_t socket_id, uint8_t address[static 16], uint16_t p
         ns_dyn_mem_free(transaction_ptr->data_ptr);
         transaction_ptr->data_ptr = NULL;
         transaction_ptr->data_len = 0;
-        if (transaction_ptr->resp_cb == NULL) {
+        if (!transaction_ptr->resp_cb && transaction_ptr->req_msg_type == COAP_MSG_TYPE_NON_CONFIRMABLE) {
             transaction_delete(transaction_ptr);
         }
     }