d718c5de8e
Unfortunately, it isn't very easy to detect whether a socket supports GSO on Linux. Hence, `quinn-udp` simply probes for its support by trying to send GSO batches and effectively disables GSO by setting the `max-gso-segments` state variable to 1 if it encounters either EINVAL (-22) or EIO (-5). For EINVAL, `quinn-udp` has an internal retry mechanism. For EIO, the `Transmit` which is passed to `quinn-udp` needs to be re-chunked and thus cannot be automatically retried. In order to avoid dropping packets, we therefore add a once-off retry step to sending a datagram whenever we hit EIO on Linux or Android. If the error was due to GSO not being supported, the 2nd attempt should be successful and going forward, even the first one should be until we roam the socket (where this state variable gets reset). These packet drops have been causing flakiness in CI ever since we merged the eBPF tests. Those disable checksum offloading which appears to trigger these errors.
Rust development guide
Firezone uses Rust for all data plane components. This directory contains the Linux and Windows clients, and low-level networking implementations related to STUN/TURN.
We target the last stable release of Rust using rust-toolchain.toml.
If you are using rustup, that is automatically handled for you.
Otherwise, ensure you have the latest stable version of Rust installed.
Reading Client logs
The Client logs are written as JSONL for machine-readability.
To make them more human-friendly, pipe them through jq like this:
cd path/to/logs # e.g. `$HOME/.cache/dev.firezone.client/data/logs` on Linux
cat *.log | jq -r '"\(.time) \(.severity) \(.message)"'
Resulting in, e.g.
2024-04-01T18:25:47.237661392Z INFO started log
2024-04-01T18:25:47.238193266Z INFO GIT_VERSION = 1.0.0-pre.11-35-gcc0d43531
2024-04-01T18:25:48.295243016Z INFO No token / actor_name on disk, starting in signed-out state
2024-04-01T18:25:48.295360641Z INFO null
Benchmarking on Linux
The recommended way for benchmarking any of the Rust components is Linux' perf utility.
For example, to attach to a running application, do:
- Ensure the binary you are profiling is compiled with the
releaseprofile. sudo perf record -g --freq 10000 --pid $(pgrep <your-binary>).- Run the speed test or whatever load-inducing task you want to measure.
sudo perf script > profile.perf- Open profiler.firefox.com and load
profile.perf
Instead of attaching to a process with --pid, you can also specify the path to executable directly.
That is useful if you want to capture perf data for a test or a micro-benchmark.