SLIP_HDRLEN
default_print((u_char *)ip, caplen - SLIP_HDRLEN);
if (caplen < SLIP_HDRLEN) {
length -= SLIP_HDRLEN;
ip = (struct ip *)(p + SLIP_HDRLEN);
default_print((u_char *)ip, caplen - SLIP_HDRLEN);
printf("ip %d: ", length + SLIP_HDRLEN);
if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
length -= SLIP_HDRLEN;
ip = (struct ip *)(p + SLIP_HDRLEN);