SLIP_MAGIC
if (!sl || sl->magic != SLIP_MAGIC)
if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {
if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
sl->magic = SLIP_MAGIC;
if (sl && sl->magic == SLIP_MAGIC)
if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)