rem: if (check_inverse(optarg, &invert)) optind++;
add: check_inverse(optarg, &invert, &optind, 0);
context: parse(int c, char **argv, int invert, unsigned int *flags,      const struct ip6t_entry *entry,      unsigned int *nfcache,      struct ip6t_entry_match **match){	struct ip6t_tcp *tcpinfo = (struct ip6t_tcp *)(*match)->data;	switch (c) {	case '1':		if (*flags & TCP_SRC_PORTS)			exit_error(PARAMETER_PROBLEM,				   "Only one `--source-port' allowed");		if (check_inverse(optarg, &invert))			optind++;		parse_tcp_ports(argv[optind-1], tcpinfo->spts);		if (invert)			tcpinfo->invflags |= IP6T_TCP_INV_SRCPT;		*flags |= TCP_SRC_PORTS;		*nfcache |= NFC_IP6_SRC_PT;		break;	case '2':		if (*flags & TCP_DST_PORTS)			exit_error(PARAMETER_PROBLEM,				   "Only one `--destination-port' allowed");		if (check_inverse(optarg, &invert))			optind++;		parse_tcp_ports(argv[optind-1], tcpinfo->dpts);		if (invert)			tcpinfo->invflags |= IP6T_TCP_INV_DSTPT;		*flags |= TCP_DST_PORTS;		*nfcache |= NFC_IP6_DST_PT;		break;	case '3':		if (*flags & TCP_FLAGS)			exit_error(PARAMETER_PROBLEM,				   "Only one of `--syn' or `--tcp-flags' "				   " allowed");		parse_tcp_flags(tcpinfo, "SYN,RST,ACK", "SYN", invert);		*flags |= TCP_FLAGS;		*nfcache |= NFC_IP6_TCPFLAGS;		break;	case '4':		if (*flags & TCP_FLAGS)			exit_error(PARAMETER_PROBLEM,				   "Only one of `--syn' or `--tcp-flags' "				   " allowed");		if (check_inverse(optarg, &invert))			optind++;		if (!argv[optind]		    || argv[optind][0] == '-' || argv[optind][0] == '!')			exit_error(PARAMETER_PROBLEM,				   "--tcp-flags requires two args.");		parse_tcp_flags(tcpinfo, optarg, argv[optind++], invert);		*flags |= TCP_FLAGS;		*nfcache |= NFC_IP6_TCPFLAGS;		break;	case '5':		if (*flags & TCP_OPTION)			exit_error(PARAMETER_PROBLEM,				   "Only one `--tcp-option' allowed");		if (check_inverse(optarg, &invert))			optind++;		parse_tcp_option(argv[optind-1], &tcpinfo->option);		if (invert)			tcpinfo->invflags |= IP6T_TCP_INV_OPTION;		*flags |= TCP_OPTION;		*nfcache |= NFC_IP6_PROTO_UNKNOWN;		break;	default:		return 0;	}	return 1;}