https://github.com/opencyphal/libudpard

A compact implementation of the Cyphal/UDP protocol in C for high-integrity real-time embedded systems
https://github.com/opencyphal/libudpard

Last synced: about 2 months ago
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A compact implementation of the Cyphal/UDP protocol in C for high-integrity real-time embedded systems

• Host: GitHub
• URL: https://github.com/opencyphal/libudpard
• Owner: OpenCyphal
• License: mit
• Created: 2022-08-05T17:03:43.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2024-08-16T14:20:16.000Z (5 months ago)
• Last Synced: 2024-11-26T01:31:03.862Z (2 months ago)
• Language: C
• Homepage:
• Size: 327 KB
• Stars: 11
• Watchers: 11
• Forks: 8
• Open Issues: 9
• Metadata Files:
  • Readme: README.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE

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README

        
# Compact Cyphal/UDP in C

[![Main Workflow](https://github.com/OpenCyphal-Garage/libudpard/actions/workflows/main.yml/badge.svg)](https://github.com/OpenCyphal-Garage/libudpard/actions/workflows/main.yml)

[![Reliability Rating](https://sonarcloud.io/api/project_badges/measure?project=libudpard&metric=reliability_rating)](https://sonarcloud.io/summary?id=libudpard)

[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=libudpard&metric=coverage)](https://sonarcloud.io/summary?id=libudpard)

[![Forum](https://img.shields.io/discourse/users.svg?server=https%3A%2F%2Fforum.opencyphal.org&color=1700b3)](https://forum.opencyphal.org)

LibUDPard is a compact implementation of the Cyphal/UDP protocol in C99/C11 for high-integrity real-time

embedded systems.

[Cyphal](https://opencyphal.org) is an open lightweight data bus standard designed for reliable intravehicular

communication in aerospace and robotic applications via CAN bus, UDP, and other robust transports.

We pronounce LibUDPard as *lib-you-dee-pee-ard*.

## Features

Some of the features listed here are intrinsic properties of Cyphal.

- Full branch coverage and extensive static analysis.

- Compliance with automatically enforceable MISRA C rules (reach out to https://forum.opencyphal.org for details).

- Detailed time complexity and memory requirement models for the benefit of real-time high-integrity applications.

- Purely reactive time-deterministic API without the need for background servicing.

- Zero-copy data pipeline on reception --

  payload is moved from the underlying NIC driver all the way to the application without copying.

- Support for redundant network interfaces with seamless interface aggregation and no fail-over delay.

- Out-of-order multi-frame transfer reassembly, including cross-transfer interleaved frames.

- Support for repetition-coding forward error correction (FEC) for lossy links (e.g., wireless)

  transparent to the application.

- No dependency on heap memory; the library can be used with fixed-size block pool allocators.

- Compatibility with all conventional 8/16/32/64-bit platforms.

- Compatibility with extremely resource-constrained baremetal environments starting from 64K ROM and 64K RAM.

- Implemented in ≈2000 lines of code.

## Usage

The library implements the Cyphal/UDP protocol, which is a transport-layer entity.

An application using this library will need to implement the presentation layer above the library,

perhaps with the help of the [Nunavut transpiler](https://github.com/OpenCyphal/nunavut),

and the network layer below the library using a third-party UDP/IP stack implementation with multicast/IGMP support

(TCP and ARP are not needed).

In the most straightforward case, the network layer can be based on the standard Berkeley socket API

or a lightweight embedded stack such as LwIP.

```mermaid

%%{init: {"fontFamily": "Ubuntu Mono, monospace", "flowchart": {"curve": "basis"}}}%%

flowchart TD

    classDef OpenCyphal color:#00DAC6,fill:#1700b3,stroke:#00DAC6,stroke-width:2px,font-weight:600

    Application <-->|messages,\nrequests,\nresponses| LibUDPard[fa:fa-code LibUDPard]

    class LibUDPard OpenCyphal

    LibUDPard <-->|multicast datagrams| UDP

    subgraph domain_udpip["3rd-party UDP/IP+IGMP stack"]

        UDP <--> IP["IPv4, IGMPv1+"] <--> MAC

    end

    MAC <--> PHY

```

To integrate the library into your application, simply copy the files under `libudpard/` into your project tree,

or add this entire repository as a submodule.

The library contains only one translation unit named `udpard.c`;

no special compiler options are needed to build it.

The library should be compatible with all conventional computer architectures where a standards-compliant C99 compiler

is available.

**Read the API docs in [`libudpard/udpard.h`](libudpard/udpard.h).**

For complete usage examples, please refer to .

## Revisions

### v1.0

Initial release.