+void interface_update_ipv6(struct ifaddrs *ifap, const char *if_name);
+void ipv6_duplicated_address(const char * if_name, const struct in6_addr * addr,
+ int hw_len, const void * hw_addr);
+void nat64_prefix_request(const char *if_name);
+void ipv6_router_expired(const char *if_name);