get_u64(const void *vp)
{
	const u_char *p = (const u_char *)vp;
	u_int64_t v;

	v  = (u_int64_t)p[0] << 56;
	v |= (u_int64_t)p[1] << 48;
	v |= (u_int64_t)p[2] << 40;
	v |= (u_int64_t)p[3] << 32;
	v |= (u_int64_t)p[4] << 24;
	v |= (u_int64_t)p[5] << 16;
	v |= (u_int64_t)p[6] << 8;
	v |= (u_int64_t)p[7];

	return (v);
}