0 /* * XEN_NETIF_EXTRA_TYPE_MCAST_{ADD,DEL}: * Backend advertises availability via 'feature-multicast-control' * xenbus node containing value '1'. * Frontend requests this feature by advertising * 'request-multicast-control' xenbus node containing value '1'. * If multicast control is requested then multicast flooding is * disabled and the frontend must explicitly register its interest * in multicast groups using dummy transmit requests containing * MCAST_{ADD,DEL} extra-info fragments. */