libnetfilter_queue 라이브러리에서 사용되는 중요한 구조체중 하나인 nfq_data 입니다.struct nfq_data { /* packet_hdr - it HAVE to be the same as struct nfqnl_msg_packet_hdr */ struct { uint32_t packet_id; /* unique ID of packet in queue in network order */ uint16_t hw_protocol; /* hw protocol in network order */ uint8_t hook; /* netfilter hook */ } packet_hdr; /* packet_hw - it HAVE to be ..