dln2_header
struct dln2_header *hdr = urb->transfer_buffer;
if (urb->actual_length < sizeof(struct dln2_header)) {
data = urb->transfer_buffer + sizeof(struct dln2_header);
len = urb->actual_length - sizeof(struct dln2_header);
struct dln2_header *hdr;
struct dln2_header hdr;
hdr = (struct dln2_header *)buf;