/* * +-multicast/broadcast * | +-rx_ok * | | ++-----L3_type (1:ipv4, 0/2:ipv6) * pkt_len(13) | | ||+ ++-L4_type(0: icmp, 1: UDP, 4: TCP) * |765|43210 76543210|7654 3210 7654 3210| * |+-Drop_err |+-L4_err |+-L4_CSUM_ERR * +--crc_err +--L3_err +--L3_CSUM_ERR * * ex) pkt_hdr 0x00680820 * drop_err, crc_err: none * pkt_length = 104 byte * 0x0820 = 0000 1000 0010 0000 => ipv4 icmp * * ex) pkt_hdr 0x004c8800 * drop_err, crc_err: none * pkt_length = 76 byte * 0x8800 = 1000 1000 0000 0000 => ipv6 mcast icmp * * [memo] * 0x0820: ipv4 icmp 0000 1000 0010 0000 * 0x8820: ipv4 icmp (broadcast) 1000 1000 0010 0000 * 0x0824: ipv4 udp (nping) 0000 1000 0010 0100 * 0x0830: ipv4 tcp (ssh) 0000 1000 0011 0000 * * 0x0800: ipv6 icmp 0000 1000 0000 0000 * 0x8800: ipv6 icmp (multicast) 1000 1000 0000 0000 * 0x8844: ipv6 UDP/MDNS mcast 1000 1000 0100 0100 * 0x0850: ipv6 tcp (ssh) 0000 1000 0101 0000 */