fixed RPL statistics bug and added parent switch stats

core/net/rpl/rpl-dag.c

@@ -358,6 +358,7 @@ rpl_select_parent(rpl_dag_t *dag)
     rpl_reset_dio_timer(dag, 1);
     PRINTF("RPL: New preferred parent, rank changed from %u to %u\n",
 	   (unsigned)dag->rank, dag->of->calculate_rank(best, 0));
+    RPL_STAT(rpl_stats.parent_switch++);
   }
 
   /* Update the DAG rank, since link-layer information may have changed

core/net/rpl/rpl-icmp6.c

@@ -571,7 +571,7 @@ dao_input(void)
 
   rep = rpl_add_route(dag, &prefix, prefixlen, &dao_sender_addr);
   if(rep == NULL) {
-    RPL_STAT(rpl_stats.memory_overflows++);
+    RPL_STAT(rpl_stats.mem_overflows++);
     PRINTF("RPL: Could not add a route after receiving a DAO\n");
     return;
   } else {

core/net/rpl/rpl-private.h

@@ -218,6 +218,7 @@ struct rpl_stats {
   uint16_t global_repairs;
   uint16_t malformed_msgs;
   uint16_t resets;
+  uint16_t parent_switch;
 };
 typedef struct rpl_stats rpl_stats_t;