Function imo_match_group

freebsd/netinet/in_mcast.c:415–435

* Find an IPv4 multicast group entry for this ip_moptions instance * which matches the specified group, and optionally an interface. * Return its index into the array, or -1 if not found. */

 * Return its index into the array, or -1 if not found.
 */
static struct in_mfilter *
imo_match_group(const struct ip_moptions *imo, const struct ifnet *ifp,
    const struct sockaddr *group)
{
	const struct sockaddr_in *gsin;
	struct in_mfilter *imf;
	struct in_multi	*inm;

	gsin = (const struct sockaddr_in *)group;

	IP_MFILTER_FOREACH(imf, &imo->imo_head) {
		inm = imf->imf_inm;
		if (inm == NULL)
			continue;
		if ((ifp == NULL || (inm->inm_ifp == ifp)) &&
		    in_hosteq(inm->inm_addr, gsin->sin_addr)) {
			break;
		}
	}
	return (imf);
}

/*
 * Find an IPv4 multicast source entry for this imo which matches