SLMAX
if ((ifr->ifr_mtu < 3) || (ifr->ifr_mtu > SLMAX)) {
#define SLBUFSIZE (SLMAX + BUFOFFSET)
if (tp->t_outq.c_cn < 2 * SLMAX + 2) {
error = clalloc(&tp->t_outq, 2 * SLMAX + 2, 0);