MLPIPHDRLEN
#if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
MLPIPHDRLEN, M_DEVBUF, M_WAITOK);
sc->sc_ifbuf = malloc(ifr->ifr_mtu + MLPIPHDRLEN, M_DEVBUF,
if (len > ifp->if_mtu + MLPIPHDRLEN)