Function sa6_embedscope

freebsd/netinet6/scope6.c:317–343

* Validate the specified scope zone ID in the sin6_scope_id field. If the ID * is unspecified (=0), needs to be specified, and the default zone ID can be * used, the default value will be used. * This routine then generates the kernel-internal form: if the address scope * of is interface-local or link-local, embed the interface index in the * address. */

 * address.
 */
int
sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
{
	u_int32_t zoneid;

	if ((zoneid = sin6->sin6_scope_id) == 0 && defaultok)
		zoneid = scope6_addr2default(&sin6->sin6_addr);

	if (zoneid != 0 &&
	    (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr))) {
		/*
		 * At this moment, we only check interface-local and
		 * link-local scope IDs, and use interface indices as the
		 * zone IDs assuming a one-to-one mapping between interfaces
		 * and links.
		 */
		if (V_if_index < zoneid || ifnet_byindex(zoneid) == NULL)
			return (ENXIO);

		/* XXX assignment to 16bit from 32bit variable */
		sin6->sin6_addr.s6_addr16[1] = htons(zoneid & 0xffff);
		sin6->sin6_scope_id = 0;
	}

	return 0;
}

/*
 * generate standard sockaddr_in6 from embedded form.