+extern subnet_t *new_subnet(void);
+extern void free_subnet(subnet_t *);
+extern void init_subnets(void);
+extern void exit_subnets(void);
+extern avl_tree_t *new_subnet_tree(void);
+extern void free_subnet_tree(avl_tree_t *);
+extern void subnet_add(struct node_t *, subnet_t *);
+extern void subnet_del(struct node_t *, subnet_t *);
+extern char *net2str(subnet_t *);
+extern subnet_t *str2net(char *);
+extern subnet_t *lookup_subnet(struct node_t *, subnet_t *);
+extern subnet_t *lookup_subnet_mac(mac_t *);
+extern subnet_t *lookup_subnet_ipv4(ipv4_t *);
+extern subnet_t *lookup_subnet_ipv6(ipv6_t *);
+extern void dump_subnets(void);