+/* Initialising trees */
+
+void init_subnets(void)
+{
+cp
+ subnet_tree = avl_alloc_tree((avl_compare_t)subnet_compare, (avl_action_t)free_subnet);
+cp
+}
+
+void exit_subnets(void)
+{
+cp
+ avl_delete_tree(subnet_tree);
+cp
+}
+
+avl_tree_t *new_subnet_tree(void)
+{
+cp
+ return avl_alloc_tree((avl_compare_t)subnet_compare, NULL);
+cp
+}
+
+void free_subnet_tree(avl_tree_t *subnet_tree)
+{
+cp
+ avl_delete_tree(subnet_tree);
+cp
+}
+