rustls VS embassy

The RustTLS project is currently setting up their own CI benchmarking workflow, so I think that you could find some inspiration there: https://github.com/rustls/rustls/issues/1385 and https://github.com/rustls/rustls/issues/1205.

I also studied this question on FFI several weeks ago in terms of "rewrite part of the system in Rust". Unexpected results could be semantic issues (e.g., different error handling methods) or security issues (FFI could be a soundness hole). I suggest going through the issues of libraries that have started rewriting work such as rust-openssl or rustls (This is the one trying to rewrite in whole rust rather than using FFI; however, you will not be able to find the mapping function in the C version and compare them). I hope this helps!

Now for rust implementation of tls. Certificates can be loaded in two ways. * Finds and loads certificates using OS specific tools3 * Uses a rust implementation of webpki4 for loading with certificates5

> Ring is mostly C/Assembly

Crypto needs to be written in Assembly to ensure that operations take a constant time, regardless of input. Writing it in a high level language like C or Rust opens you up to the compiler "optimising" routines and making them no longer constant time.

But you already knew this. And you also knew that the security audit (https://github.com/rustls/rustls/blob/master/audit/TLS-01-re...) of ring was favourable

> No issues were found with regards to the cryptographic engineering of rustls or its underlying ring library. A recommendation is provided in TLS-01-001 to optionally supplement the already solid cryptographic library with another cryptographic provider (EverCrypt) with an added benefit of formally verified cryptographic primitives. Overall, it is very clear that the developers of rustls have an extensive knowledge on how to correctly implement the TLS stack whilst avoiding the common pitfalls that surround the TLS ecosystem. This knowledge has translated reliably into an implementation of exceptional quality.

You said

> a standard library with feature flags and editions would make rust ridiculously much more productive

What's the difference between opting into a library with a feature flag and opting in with a line in Cargo.toml? Let's say you want to use the de-facto regex library. Would it really be ridiculously productive if you said you wanted the "regex" feature flag instead of the "regex" crate?

I do agree that the standard library does need a versioning story so they can remove long deprecated functions. Where it gets complicated is if a new method is reintroduced using the same name in a later edition.

I used the commands listed in the .sh file here: https://github.com/rustls/rustls/tree/main/test-ca to generate keys/certs for a server and a client (with IP.1 records for SANs). I have added the local root CA to the trust store of each VM.

This is great news, this was our single biggest annoyance with rustls. One of our cloud providers choses to issue their hosted postgres instances with TLS certificates with IP addresses. Unusual, but valid per the spec, so why not. Apparently a practise that's also popular in kubernetes settings, so I'm somewhat surprised it took 5 years to close the issue, but now I can finally recommend people to use rustls without mentioning any gotchas.

I believe it is more relevant than you think: servers running in containers, web assembler tasks running in browsers, embedded devices and kernels with total control of the system, all have the ability to do something more sensible than plain out SIGABRT or similar, and in many the case is not that the complete system is falling down. For example RustTLS is looking into allowing fallible allocators and as a pretty general-purpose library that seems like a nice feature. I do wish ulimit -v worked in a sensible manner with applications.

thanks. looked that up. for the curious: https://embassy.dev/

Running the Embassy RP2040 USB CDC ACM serial example takes about 5 seconds on a Pico.

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

Async solves different problems, you can, for instance, have just a single-threaded CPU and still have a nice API if you have async-await. It might not be so cool at a higher level as Go's approach of channels and threads, but it's cool in embedded, read this:

https://github.com/embassy-rs/embassy?tab=readme-ov-file#rus...

"Rust's async/await allows for unprecedently easy and efficient multitasking in embedded systems. Tasks get transformed at compile time into state machines that get run cooperatively. It requires no dynamic memory allocation, and runs on a single stack, so no per-task stack size tuning is required. It obsoletes the need for a traditional RTOS with kernel context switching, and is faster and smaller than one!"

I'm just toying with Raspberry Pi Pico and it's pretty nice.

Go and Rust have different use cases, the async-await is nice at a low level.

I have not yet dipped by toes in the Rust waters, but reading about the embassy project is actually what piqued my curiosity about using C++ coroutines in embedded. Are you familiar with the project or have you found it lacking?

I think I get the basics (shoutout to the Rust Embedded Working Group!), and I've started looking for the stack I'd be using. I think Embassy is really amazing, as well as the work of the ESP team -- hats off.

> }

And this is how to do it using embassy, which is an async framework for embedded in rust:

https://github.com/embassy-rs/embassy/blob/main/examples/rp/...

> not good for embedded

embassy begs to differ

https://embassy.dev/

async/await is really just a syntax for building state machines in a way that resembles regular code. It's compiled down to the same code that you would write by hand anyway (early on it had some bloat in state size but I think it's all fixed now).

And embedded has a lot of state machines!

You can run multiple executors at different interrupt priority levels (with multiple tasks per executor), which allows tasks on the higher priority executor to interrupt other tasks. Here's an example https://github.com/embassy-rs/embassy/blob/main/examples/nrf...