802.3_layer2.dogma

dogma_v1 utf-8
- identifier  = 802.3_layer2
- description = IEEE 802.3 Ethernet frame, layer 2
- dogma       = https://github.com/kstenerud/dogma/blob/master/v1/dogma_v1.md
- note        = Words are byte-ordered big endian, but every octet is sent LSB first.

frame             = preamble
                  & frame_start
                  & dst_address
                  & src_address
                  & var(etype, ether_type)
                  & [
                      etype.type = 0x8100: dot1q_frame;
                      etype.type = 0x88a8: double_tag_frame;
                                         : payload_by_type(etype.type, 46);
                    ]
                  & frame_check
                  ;
preamble          = uint(8, 0b01010101){7};
frame_start       = uint(8, 0b11010101);
dst_address       = uint(48, ~);
src_address       = uint(48, ~);
ether_type        = uint(16, var(type, ~));
frame_check       = uint(32, ~);

dot1q_frame       = tag_control_info
                  & var(etype, ether_type)
                  & payload_by_type(etype.type, 42)
                  ;
double_tag_frame  = service_tag
                  & uint(16, 0x8100)
                  & customer_tag
                  & var(etype, ether_type)
                  & payload_by_type(etype.type, 38)
                  ;

tag_control_info  = priority & drop_eligible & vlan_id;
priority          = uint(3, ~);
drop_eligible     = uint(1, ~);
vlan_id           = uint(12, ~);
service_tag       = tag_control_info;
customer_tag      = tag_control_info;

payload_by_type(type, min_size) = [
                                    type >= min_size & type <= 1500: generic_payload(type);
                                    type = 0x0800                  : ipv4;
                                    type = 0x86dd                  : ipv6;
                                    # TODO: The rest of the payload types
                                  ];
generic_payload(length)         = uint(8,~){length};
ipv4: bits                      = """https://somewhere/ipv4.dogma""";
ipv6: bits                      = """https://somewhere/ipv6.dogma""";