ETHER_FRAME_START                := BUFFER

ETHER_FRAME_DEST_MAC             := ETHER_FRAME_START + $00
ETHER_FRAME_SRC_MAC              := ETHER_FRAME_START + $06
ETHER_FRAME_TYPE                 := ETHER_FRAME_START + $0C
ETHER_FRAME_END                  := ETHER_FRAME_START + $0E

IP_HEADER_START                  := ETHER_FRAME_END
IP_HEADER_HEADER_LEN             := IP_HEADER_START + $00
IP_HEADER_DIFF_SVC               := IP_HEADER_START + $01
IP_HEADER_TOTAL_LEN              := IP_HEADER_START + $02
IP_HEADER_ID                     := IP_HEADER_START + $04
IP_HEADER_FLAGS                  := IP_HEADER_START + $06
IP_HEADER_FRAG_OFFSET            := IP_HEADER_START + $07
IP_HEADER_TTL                    := IP_HEADER_START + $08
IP_HEADER_PROTOCOL               := IP_HEADER_START + $09
IP_HEADER_HEADER_CKSUM           := IP_HEADER_START + $0A
IP_HEADER_SRC_IP_ADDR            := IP_HEADER_START + $0C
IP_HEADER_DEST_IP_ADDR           := IP_HEADER_START + $10
IP_HEADER_END                    := IP_HEADER_START + $14

IP_PACKAGE_ICMP_START            := IP_HEADER_END
IP_PACKAGE_ICMP_TYPE             := IP_PACKAGE_ICMP_START + $00
IP_PACKAGE_ICMP_CODE             := IP_PACKAGE_ICMP_START + $01
IP_PACKAGE_ICMP_CHECKSUM         := IP_PACKAGE_ICMP_START + $02
IP_PACKAGE_ICMP_ECHO_ID          := IP_PACKAGE_ICMP_START + $04
IP_PACKAGE_ICMP_ECHO_SEQ_NUMBER  := IP_PACKAGE_ICMP_START + $06
IP_PACKAGE_ICMP_ECHO_PAYLOAD     := IP_PACKAGE_ICMP_START + $08

IP_PACKAGE_IGMP_START            := IP_HEADER_END

IP_PACKAGE_UDP_START             := IP_HEADER_END
IP_PACKAGE_UDP_SRC_PORT          := IP_PACKAGE_UDP_START + $00
IP_PACKAGE_UDP_DEST_PORT         := IP_PACKAGE_UDP_START + $02
IP_PACKAGE_UDP_LENGTH            := IP_PACKAGE_UDP_START + $04
IP_PACKAGE_UDP_CHECKSUM          := IP_PACKAGE_UDP_START + $06
IP_PACKAGE_UDP_PAYLOAD           := IP_PACKAGE_UDP_START + $08

PROTOCOL_ICMP                    := 1
PROTOCOL_IGMP                    := 2
PROTOCOL_UDP                     := 17