Changed the rate limiting function to calculate the values runtime

This allows changing of memory after calling packet drop threshold

Author: Mika Tervonen

source/MAC/IEEE802_15_4/mac_mcps_sap.c

@@ -74,7 +74,7 @@ static void mac_pd_data_confirm_failure_handle(protocol_interface_rf_mac_setup_s
 
 static int8_t mac_tasklet_event_handler = -1;
 
-static ns_mem_heap_size_t ns_dyn_mem_rate_limiting_threshold = 0xFFFFFFFF;
+static uint8_t ns_dyn_mem_rate_limiting_threshold_percentage = 0;
 
 /**
  * Get PHY time stamp.
@@ -2127,8 +2127,12 @@ mac_pre_parsed_frame_t *mcps_sap_pre_parsed_frame_buffer_get(const uint8_t *data
 {
     // check that system has enough space to handle the new packet
     const mem_stat_t *ns_dyn_mem_stat = ns_dyn_mem_get_mem_stat();
-    if (ns_dyn_mem_stat && ns_dyn_mem_stat->heap_sector_allocated_bytes > ns_dyn_mem_rate_limiting_threshold) {
-        return NULL;
+
+    if (ns_dyn_mem_stat && ns_dyn_mem_rate_limiting_threshold_percentage) {
+        if (ns_dyn_mem_stat->heap_sector_allocated_bytes > ns_dyn_mem_stat->heap_sector_size / 100 * (100 - ns_dyn_mem_rate_limiting_threshold_percentage)) {
+            // Packet is dropped from radio interface because there is not enough memory to handle incoming packets.
+            return NULL;
+        }
     }
 
     mac_pre_parsed_frame_t *buffer = ns_dyn_mem_temporary_alloc(sizeof(mac_pre_parsed_frame_t) + frame_length);
@@ -2365,10 +2369,8 @@ uint8_t mcps_sap_purge_reg_handler(protocol_interface_rf_mac_setup_s *rf_mac_set
 
 int mcps_packet_ingress_rate_limit_by_memory(uint8_t free_heap_percentage)
 {
-    const mem_stat_t *ns_dyn_mem_stat = ns_dyn_mem_get_mem_stat();
-
-    if (ns_dyn_mem_stat && free_heap_percentage < 100) {
-        ns_dyn_mem_rate_limiting_threshold = ns_dyn_mem_stat->heap_sector_size / 100 * (100 - free_heap_percentage);
+    if (free_heap_percentage < 100) {
+        ns_dyn_mem_rate_limiting_threshold_percentage = free_heap_percentage;
         return 0;
     }