extern uword unformat_ip_address_family (unformat_input_t * input,
va_list * args);
extern u8 *format_ip_address_family (u8 * s, va_list * args);
extern uword unformat_ip_address_family (unformat_input_t * input,
va_list * args);
extern u8 *format_ip_address_family (u8 * s, va_list * args);