FHSS: Calculate hop count using RPL rank

Author: Jarkko Paso

source/6LoWPAN/ws/ws_bootstrap.c

@@ -78,6 +78,8 @@ static bool ws_bootstrap_state_wait_rpl(struct protocol_interface_info_entry *cu
 static int8_t ws_bootsrap_event_trig(ws_bootsrap_event_type_e event_type, int8_t interface_id, arm_library_event_priority_e priority, void *event_data);
 
 static bool ws_bootstrap_neighbor_info_request(struct protocol_interface_info_entry *interface, const uint8_t *mac_64, llc_neighbour_req_t * neighbor_buffer, bool request_new);
+static uint16_t ws_bootstrap_route_cost_calculate(protocol_interface_info_entry_t *cur);
+static uint16_t ws_bootstrap_get_min_rank_inc(protocol_interface_info_entry_t *cur);
 
 mac_neighbor_table_entry_t * ws_bootstrap_mac_neighbor_add(struct protocol_interface_info_entry *interface, const uint8_t *src64)
 {
@@ -208,6 +210,9 @@ static int8_t ws_enable_fhss(protocol_interface_info_entry_t *cur)
     if (ns_fhss_set_neighbor_info_fp(fhss_api, &ws_get_neighbor_info)) {
         return -1;
     }
+    if (cur->bootsrap_mode == ARM_NWK_BOOTSRAP_MODE_6LoWPAN_BORDER_ROUTER) {
+        ns_fhss_ws_set_hop_count(fhss_api, 0);
+    }
     cur->ws_info->fhss_api = fhss_api;
     return 0;
 }
@@ -979,6 +984,15 @@ static void ws_bootstrap_rpl_callback(rpl_event_t event, void *handle)
     if (event == RPL_EVENT_DAO_DONE) {
         // Trigger statemachine check
         cur->bootsrap_state_machine_cnt = 1;
+        uint16_t own_rank = ws_bootstrap_route_cost_calculate(cur);
+        uint16_t rank_inc = ws_bootstrap_get_min_rank_inc(cur);
+        if (own_rank == 0xffff || rank_inc == 0xffff) {
+            return;
+        }
+        // Calculate own hop count. This method gets inaccurate when hop count increases.
+        uint8_t own_hop = (own_rank - rank_inc) / rank_inc;
+        ns_fhss_ws_set_hop_count(cur->ws_info->fhss_api, own_hop);
+
     } else if(event == RPL_EVENT_LOCAL_REPAIR_NO_MORE_DIS) {
         /*
          * RPL goes to passive mode, but does not require any extra changed
@@ -1158,20 +1172,40 @@ static void ws_bootstrap_pan_config_solicit(protocol_interface_info_entry_t *cur
 
     ws_llc_asynch_request(cur, &async_req);
 }
-static uint16_t ws_bootstrap_route_cost_calculate(protocol_interface_info_entry_t *cur)
-{
-    // Find selected parent from RPL
 
+static struct rpl_instance *ws_get_rpl_instance(protocol_interface_info_entry_t *cur)
+{
+    if (!cur || !cur->rpl_domain) {
+        return NULL;
+    }
     struct rpl_instance *best_instance = NULL;
-
     ns_list_foreach(struct rpl_instance, instance, &cur->rpl_domain->instances) {
         best_instance = instance;
         // Select best grounded and lowest rank? But there should be only one really
     }
-    if (!best_instance) {
+    return best_instance;
+}
+
+static uint16_t ws_bootstrap_route_cost_calculate(protocol_interface_info_entry_t *cur)
+{
+    struct rpl_instance *rpl_instance = ws_get_rpl_instance(cur);
+    if (!rpl_instance) {
+        return 0xffff;
+    }
+    return rpl_control_current_rank(rpl_instance);
+}
+
+static uint16_t ws_bootstrap_get_min_rank_inc(protocol_interface_info_entry_t *cur)
+{
+    struct rpl_instance *rpl_instance = ws_get_rpl_instance(cur);
+    if (!rpl_instance) {
+        return 0xffff;
+    }
+    struct rpl_dodag_info_t dodag_info;
+    if (!rpl_control_read_dodag_info(rpl_instance, &dodag_info)) {
         return 0xffff;
     }
-    return rpl_control_current_rank(best_instance);
+    return dodag_info.dag_min_hop_rank_inc;
 }
 
 static void ws_bootstrap_pan_advert(protocol_interface_info_entry_t *cur)