domo/doc/proto.md

13 KiB

Version: 1
Authored by: Raine <raine@ixvd.net>
Status: planning

Prelude

Version 1 has zero security on itself. This can be changed with something like TLS but that's up to the implementer.

Structure

Packets are sent in big endian.

offset size name description example
0x00 1 byte version This describes the version of the packet 0x01
0x01 4 bytes dest This describes who the packet is for a.k.a. destination device id 0xAABBCCDD
0x05 4 bytes src This describes who sent the packet a.k.a. source device id 0xAABBCCDD
0x09 4 bytes packet_id This is the unique identifier of the packet 0xFAB1B39D
0x0D 4 bytes reply_to This describes what this packet is replying to, if initial message, value is 0x0 0x00000000
0x11 1 byte command This describes what kind of command is sent 0x00
0x12 2 bytes data_length This describes the length of the data in bytes 0x0001
0x14 <0x11-0x12:data_length> data This is the data of the command 0x0000
0x14 + <0x11-0x12:data_length> 4 bytes checksum This is the CRC32 checksum of the packet without the checksum. 0x00000000

Packets in practice

Statuses

When an error occurs the response should be a 0x0E (error command).
This can contain error data.

To mark a success, you should just send back the expected response.

Reserved fields

The "reserved" column (if present) will state what should be filled in by each side.

  • "no": this should be filled in by both sides. (default)
  • "request": this should only be filled in the request.
  • "response": this should only be filled in the response.

Error checking

If the CRC32 doesn't match up the receiver will send a 0x0E (error) packet to the probable source.
The error code 0x01/net_broken_packet should be used. The metadata may contain some textual info on what went wrong.
The master will not track the broken packet's packet_id, so the slave can send it again.

Data types

Domo has a data framework reliant on data types. These define what kind of data the property holds.

data_type physical type (rust types) size virtual type description
0x0* Meta
0x00 None 0 bytes Nothing Nothing, mostly used internally or as example.
0x01 Vec<DataType> 2+ bytes Array An array of DataTypes. first two bytes is the u16 length
0x1* Simple
0x10 bool 1 byte Switch A simple switch with two states. 0x00 = off, 0x01 = on, 0x02 = toggle
0x11 u8 1 byte Slider A simple slider with u8 precision.
0x12 [u8; 256] 256 bytes Text A simple bit of text.
0x2* Cosmetic
0x20 [u8; 3] 3 bytes Color An RGB value.
0x9* Time & Space
0x90 u64 8 bytes Seconds A simple value that is in seconds.
0xF* Domo types
0xF0 [u8; 4] 4 bytes Domo node reference A reference to a node.

Dynamic data (dynamic_data)

Dynamic data is a data snippet with a prop_data_type byte and the data next to it.

Note

: this section uses relative offset

offset size name description example
0x00 1 byte prop_data_type Describes the data type 0x00
0x01 depending on prop_data_type data The data

Commands

These are the default commands. All Domo nodes should support these.

Note: all offsets are absolute.

0x0* - Node management

These are commands specifically for management of the nodes.

0x00 - Ping

Check to see if a node is up.

Command data

there is no command data.

0x01 - Register node

This command will register a node.

You can try to register as a node with a specific device_id but this might result in an error 0x03.
Leave 0 to get a random id.

Command data

offset size name description reserved example
0x14 4 bytes device_id the device identifier. leave 0x00000000 to get random id no 0x00000000

0x02 - Remove node

Remove node from network

Command data

there is no extra data required.

0x03 - Register property

Command data

offset size name description reserved example
0x14 32 bytes property_name The name of the property as a UTF-8 string. no "Power"
0x34 1 byte data_type The type of data; see "Data types". no 0x01
0x35 1 byte read_only Whether the property is readonly.
(0x00 = no, 0x01 = yes)
no 0x00

0x04 - Remove property

Command data

offset size name description reserved example
0x14 32 bytes property_name The name of the property as a UTF-8 string. no "Power"

0x0E - Error

Send a packet to state an error occurred.

Command data

offset size name description example
0x14 1 byte error_code error code; check 'Error codes' 0x00
0x15 2 bytes metadata_length metadata length 0x0000
0x17 <0x14-0x15:metadata_length> metadata metadata

Error codes

status_code name description recoverable
0x1* net_* Network errors
0x00 net_duplicate_packet reply_to packet is invalid because another packet was sent recently with same packet_id. resend with different packet_id
0x01 net_broken_packet recent packet was broken. resend packet
0x02 net_invalid_packet the packet sent is not valid send packet with proper values
0x03 net_addr_in_use the addr requested is in use already register with another id or 0
0x04 net_dest_unreachable the destination could not be reached no
0x1* errc_* Client errors
0x10 errc_not_registered client is not registered register client
0x2* errs_* Server errors
0x20 errs_not_delivered server could not deliver packet. depends on situation

0x1* - Properties control

0x10 - Get property

Get a properties value

Command data

offset size name description reserved example
0x14 32 bytes property_name The name of the property as a UTF-8 string. no "Power"
0x34 dynamic dynamic_data Dynamic data snippet response 0x0100

0x11 - Set property

Command data

offset size name description reserved example
0x14 32 bytes property_name The name of the property as a UTF-8 string. no "Power"
0x34 dynamic dynamic_data Dynamic data snippet no 0x0100

0x12 - Reset property

Command data

offset size name description reserved example
0x14 32 bytes property_name The name of the property as a UTF-8 string. no "Power"

0x1A - Subscribe to property

offset size name description reserved example
0x14 4 bytes device_id Who's property? no 0x00000000
0x18 32 bytes property_name The name of the property as a UTF-8 string. no "Power"

0x1A - Unsubscribe to property

offset size name description reserved example
0x14 4 bytes device_id Who's property? no 0x00000000
0x18 32 bytes property_name The name of the property as a UTF-8 string. no "Power"