PPL_HDR_RESERVED
memset(pplhdr->reserved, 0xff, PPL_HDR_RESERVED);
memset(pplhdr->reserved, 0xff, PPL_HDR_RESERVED);
(PPL_HEADER_SIZE - PPL_HDR_RESERVED - 4 * sizeof(__le32) - sizeof(__le64))
__u8 reserved[PPL_HDR_RESERVED];/* reserved space, fill with 0xff */