USBPF_HDR_LEN
bpfattach(ifp, DLT_USB, USBPF_HDR_LEN);
totlen = USBPF_HDR_LEN + (USBPF_FRAME_HDR_LEN * nframes);
ptr += USBPF_HDR_LEN;
(sizeof(struct usbpf_pkthdr) == USBPF_HDR_LEN) ? 1 : -1];
ptr += USBPF_HDR_LEN;
ptr_len -= USBPF_HDR_LEN;
memcpy(&up_temp, ptr - USBPF_HDR_LEN, sizeof(up_temp));
(int)(up->up_totlen - USBPF_HDR_LEN -
for ( ; v >= USBPF_HDR_LEN; v >>= 1) {