add: if (invert) exit_error(PARAMETER_PROBLEM, "multiport does not support invert");
context: parse(int c, char **argv, int invert, unsigned int *flags,      const struct ipt_entry *entry,      unsigned int *nfcache,      struct ipt_entry_match **match){	const char *proto;	struct ipt_multiport *multiinfo		= (struct ipt_multiport *)(*match)->data;	switch (c) {	case '1':		proto = check_proto(entry);		multiinfo->count = parse_multi_ports(argv[optind-1],						     multiinfo->ports, proto);		multiinfo->flags = IPT_MULTIPORT_SOURCE;		*nfcache |= NFC_IP_SRC_PT;		break;	case '2':		proto = check_proto(entry);		multiinfo->count = parse_multi_ports(argv[optind-1],						     multiinfo->ports, proto);		multiinfo->flags = IPT_MULTIPORT_DESTINATION;		*nfcache |= NFC_IP_DST_PT;		break;	case '3':		proto = check_proto(entry);		multiinfo->count = parse_multi_ports(argv[optind-1],						     multiinfo->ports, proto);		multiinfo->flags = IPT_MULTIPORT_EITHER;		*nfcache |= NFC_IP_SRC_PT | NFC_IP_DST_PT;		break;	default:		return 0;	}	if (*flags)		exit_error(PARAMETER_PROBLEM,			   "multiport can only have one option");	*flags = 1;	return 1;}