Function if_delmulti

freebsd/net/if.c:3590–3613

* Delete a multicast group membership by network-layer group address. * * Returns ENOENT if the entry could not be found. If ifp no longer * exists, results are undefined. This entry point should only be used * from subsystems which do appropriate locking to hold ifp for the * duration of the call. * Network-layer protocol domains must use if_delmulti_ifma(). */

 * Network-layer protocol domains must use if_delmulti_ifma().
 */
int
if_delmulti(struct ifnet *ifp, struct sockaddr *sa)
{
	struct ifmultiaddr *ifma;
	int lastref;

	KASSERT(ifp, ("%s: NULL ifp", __func__));

	IF_ADDR_WLOCK(ifp);
	lastref = 0;
	ifma = if_findmulti(ifp, sa);
	if (ifma != NULL)
		lastref = if_delmulti_locked(ifp, ifma, 0);
	IF_ADDR_WUNLOCK(ifp);

	if (ifma == NULL)
		return (ENOENT);

	if (lastref && ifp->if_ioctl != NULL) {
		(void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, 0);
	}

	return (0);
}

/*
 * Delete all multicast group membership for an interface.