union sockaddru {
	struct sockaddr		sa;
	struct sockaddr_in	sin;
	struct sockaddr_in6	sin6;
};

unsigned parse_scope(char *str)
{
	int sockfd = socket(AF_INET, SOCK_STREAM, 0);
	struct ifreq ifr;

	memset(&ifr, 0, sizeof(ifr));
	strncpy(ifr.ifr_name, str, sizeof(ifr.ifr_name));
	if (0 == ioctl(sockfd, SIOCGIFINDEX, &ifr)) {
		close(sockfd);
		return ifr.ifr_ifindex;
	}
	printf("ioctl(sockfd, SIOCGIFINDEX, '%s'): %s\n", str, strerror(errno));
	exit(2);
}

union sockaddru *parse_sockaddru(char *_str)
{
	char *str = strdup(_str);
	union sockaddru *sau = calloc(1, sizeof(*sau));
	char *percent = strchr(str, '%');
	char *at = strchr(str, '@');
	int port = 1701;

	if (at) {
		port = atoi(at + 1);
		if ((port < 0) || (port > 65535)) {
			printf("Invalid port number: %d\n", port);
			exit(1);
		}
		*at = 0;
	}

	if (strchr(str, ':')) {
		sau->sin6.sin6_family = AF_INET6;
		sau->sin6.sin6_port = htons(port);
		if (percent)
			*percent = 0;
		if (!inet_pton(AF_INET6, str, &sau->sin6.sin6_addr)) {
			printf("Could not parse '%s' as IPv6\n", str);
			exit(1);
		}
		if (percent)
			sau->sin6.sin6_scope_id = parse_scope(percent + 1);
printf("port = %u\n", (unsigned)(ntohs(sau->sin6.sin6_port)));
	} else {
		if (percent) {
			printf("scope not supported in IPv4 address\n");
			exit(1);
		}
		sau->sin.sin_family = AF_INET;
		sau->sin.sin_port = htons(port);
printf("port = %u\n", (unsigned)(ntohs(sau->sin.sin_port)));
		if (!inet_pton(AF_INET, str, &sau->sin.sin_addr)) {
			printf("Could not parse '%s' as IPv4\n", str);
			exit(1);
		}
	}

	return sau;
}

char *format_su(union sockaddru *su, char *tmp, size_t tmp_len)
{
	const char *scope = "";
	const char *a;
	char t2[64], t3[16];
	unsigned short port;

	if (su->sa.sa_family == AF_INET) {
		a = inet_ntop(AF_INET, &su->sin.sin_addr, t2, sizeof t2);
		port = ntohs(su->sin.sin_port);
	} else if (su->sa.sa_family == AF_INET6) {
		a = inet_ntop(AF_INET6, &su->sin6.sin6_addr, t2, sizeof t2);
		port = ntohs(su->sin6.sin6_port);
		if (su->sin6.sin6_scope_id) {
			snprintf(t3, sizeof(t3), "%%%u",
				su->sin6.sin6_scope_id);
			scope = t3;
		}
	} else
		return NULL;

	snprintf(tmp, tmp_len, "%s%s %d", a, scope, port);
	return tmp;
}

#if 0
void print_p_sa_u(union pppol2tp_sa_union *p_sa_u, int len)
{
	char tmp[64];

	if (len == sizeof(p_sa_u->sa4))
		printf( "sa4 {\n"
			"	sa_family   = %u\n"
			"	sa_protocol = %u\n"
			"	.pid        = %d\n"
			"	.fd         = %d\n"
			"	.addr       = %s\n"
			"	.s_tunnel   = %u\n"
			"	.s_session  = %u\n"
			"	.d_tunnel   = %u\n"
			"	.d_session  = %u\n}\n",
			(unsigned)p_sa_u->sa4.sa_family,
			(unsigned)p_sa_u->sa4.sa_protocol,
			(int)p_sa_u->sa4.pppol2tp.pid,
			(int)p_sa_u->sa4.pppol2tp.fd,
			format_su((void *)&p_sa_u->sa4.pppol2tp.addr, tmp, sizeof(tmp)),
			(unsigned)p_sa_u->sa4.pppol2tp.s_tunnel,
			(unsigned)p_sa_u->sa4.pppol2tp.s_session,
			(unsigned)p_sa_u->sa4.pppol2tp.d_tunnel,
			(unsigned)p_sa_u->sa4.pppol2tp.d_session);
	else if (len == sizeof(p_sa_u->sa6))
		printf( "sa6 {\n"
			"	sa_family   = %u\n"
			"	sa_protocol = %u\n"
			"	.pid        = %d\n"
			"	.fd         = %d\n"
			"	.addr       = %s\n"
			"	.s_tunnel   = %u\n"
			"	.s_session  = %u\n"
			"	.d_tunnel   = %u\n"
			"	.d_session  = %u\n}\n",
			(unsigned)p_sa_u->sa6.sa_family,
			(unsigned)p_sa_u->sa6.sa_protocol,
			(int)p_sa_u->sa6.pppol2tp.pid,
			(int)p_sa_u->sa6.pppol2tp.fd,
			format_su((void *)&p_sa_u->sa6.pppol2tp.addr, tmp, sizeof(tmp)),
			(unsigned)p_sa_u->sa6.pppol2tp.s_tunnel,
			(unsigned)p_sa_u->sa6.pppol2tp.s_session,
			(unsigned)p_sa_u->sa6.pppol2tp.d_tunnel,
			(unsigned)p_sa_u->sa6.pppol2tp.d_session);
	else if (len == sizeof(p_sa_u->sa4_v3))
		;
	else if (len == sizeof(p_sa_u->sa6_v3))
		;
	else {
		fprintf(stderr, "print_p_sa_u: unknown len(%d)!\n", len);
		exit(2);
	}
}
#endif