Unified Diagnostics Services (UDS) Protocol

This crate offers an ergonomic, no_std-friendly implementation of the UDS (ISO 14229) protocol codec in Rust. It targets embedded ECU diagnostics and desktop tooling alike: encoding and decoding UDS protocol messages — and custom data types — with no required allocator and no async runtime. It is not in a complete state yet, please check back soon!

This library provides serialization and deserialization of UDS messages. It is based on the ISO 14229-1:2020 standard.

Service Name	Request SID	Response SID	Support
DiagnosticSessionControl	0x10	0x50	✓
EcuReset	0x11	0x51	✓
ClearDiagnosticInformation	0x14	0x54	✓
ReadDTCInformation	0x19	0x59	Partial
ReadDataByIdentifier	0x22	0x62	✓
ReadMemoryByAddress	0x23	0x63
ReadScalingDataByIdentifier	0x24	0x64
SecurityAccess	0x27	0x67	✓
CommunicationControl	0x28	0x68	✓
Authentication	0x29	0x69
ReadDataByPeriodicIdentifier	0x2A	0x6A
DynamicallyDefineDataIdentifier	0x2C	0x6C
WriteDataByIdentifier	0x2E	0x6E	✓
InputOutputControlByIdentifier	0x2F	0x6F
RoutineControl	0x31	0x71	✓
RequestDownload	0x34	0x74	✓
RequestUpload	0x35	0x75	✓
TransferData	0x36	0x76	✓
RequestTransferExit	0x37	0x77	✓
RequestFileTransfer	0x38	0x78	✓
WriteMemoryByAddress	0x3D	0x7D
TesterPresent	0x3E	0x7E	✓
AccessTimingParameters1	0x83	0xC3
SecuredDataTransmission	0x84	0xC4
ControlDtcSetting	0x85	0xC5	✓
ResponseOnEvent	0x86	0xC6
LinkControl	0x87	0xC7

Features

Default is std. The crate is no_std and allocation-free at its core; everything below is additive.

Feature	Implies	What it gives you
std (default)	alloc	std::error::Error for [Error], and embedded_io's std layer. Turn it off for bare metal.
alloc	—	The alloc-only conveniences. Nothing in the wire codec needs it; encoding and decoding work with borrowed slices alone.
serde	—	Serialize/Deserialize on the request, response and parameter types. The only optional integration usable on a bare-metal target: it is wired as a core-only dependency and picks up serde's alloc/std layers only when this crate's own are on.
utoipa	std, serde	ToSchema for OpenAPI generation.
clap	std	ValueEnum on the sub-function enums, for building a CLI tester.

Two implications are worth knowing about:

• utoipa implies serde because a ToSchema here describes the serde representation. Several types serialize as a single protocol byte rather than as their Rust shape — a DataFormatIdentifier is 33, not {"compression_method":2,"encryption_method":1} — and the schemas are written to match. Without serde the schema would describe a wire format that build cannot produce.
• utoipa and clap imply std because their derive macros expand to std::, String and Vec paths inside this crate, which cannot compile under #![no_std].

With serde enabled, the types that carry a range invariant deserialize through the same classifier the wire decoder uses, so a hand-written payload cannot construct a value that would encode to an illegal byte.

Integration

uds_protocol is a synchronous, allocation-free codec. It owns no sockets, buffers, or async runtime. To use it over any transport (DoIP, UDSonIP, ISO-TP, …):

• Decode an inbound frame from the &[u8] you received.
• Encode an outbound frame into any embedded_io::Write (or a caller-owned buffer sized with encoded_size()).

Drive the I/O loop from your own sync or async layer — the crate never blocks or awaits.

Encode (build a request)

use uds_protocol::{Encode, TesterPresentRequest};

let req = TesterPresentRequest::new(false);
let mut buf = [0u8; 8];
let mut writer = buf.as_mut_slice();
let written = Encode::encode(&req, &mut writer).unwrap();
// `buf[..written]` is the wire frame, ready to hand to your transport.

Decode (parse a response)

use uds_protocol::{Decode, Response};

// `frame` is the &[u8] your transport handed you.
let frame = [0x7E, 0x00];
let (response, _rest) = Response::decode(&frame).unwrap();

The decoded value borrows from frame: it points into that buffer (like a struct overlaid on a char buf[]) and is valid only while frame lives. Copy out any fields you need to keep before the buffer is reused.

Service coverage

These services decode into typed [Request]/[Response] variants: DiagnosticSessionControl, EcuReset, SecurityAccess, CommunicationControl, TesterPresent, ControlDtcSetting, ReadDataByIdentifier, WriteDataByIdentifier, ClearDiagnosticInfo, ReadDtcInfo, RoutineControl, RequestDownload, RequestUpload, TransferData, RequestTransferExit, RequestFileTransfer, and NegativeResponse.

All other services enumerated in [UdsServiceType] (e.g. Authentication, ReadMemoryByAddress, ResponseOnEvent) are not individually modeled. Frames for them decode into [Request::Other] / [Response::Other], carrying the service type and raw payload bytes for pass-through.

Wire codec dependency

uds_protocol builds its byte-level decoding on top of the automotive-wire-codec crate, and re-exports its Incomplete, TrailingBytes and InvalidWidth types and its codec traits (Encode, Decode, DecodeIter) at the crate root. These types are intentionally part of uds_protocol's public API: they are shared across the Luminar automotive protocol crates so that callers handling multiple protocols see one consistent short-read/trailing-data error shape. Because of this, a semver-major release of automotive-wire-codec is a breaking change for uds_protocol as well.

Footnotes

1. AccessTimingParameters (0x83) was defined in ISO 14229-1:2013 and removed in the 2020 edition. UdsServiceType still names it so a 2013-era service byte round-trips rather than becoming an unrecognized Other, but it is not part of the standard this crate targets. ↩