usbpf_framehdr
struct usbpf_framehdr *uf;
uf = (struct usbpf_framehdr *)ptr;
(sizeof(struct usbpf_framehdr) == USBPF_FRAME_HDR_LEN) ? 1 : -1];
const struct usbpf_framehdr *uf;
uf = (const struct usbpf_framehdr *)ptr;