At present, the TCP DNS server we use in `connlib` exposes an opaque `SocketHandle` with each received query. This handle refers to the socket that the query was received on. The response needs to be sent back on the same socket because it effectively refers to the TCP stream that was established. We need to track this `SocketHandle` all the way through to our user-space DNS client in `connlib` which actually resolves queries with a DNS server. In order to be able to reuse this DNS client on the Gateway where we receive DNS queries using a user-space socket (and thus don't have such a `SocketHandle`), we need to remove this abstraction from the public API of the TCP DNS server. A TCP stream is effectively identified by the source and destination socket address: A given 4-tuple (source IP, source port, destination IP, destination port) can only ever hold a single TCP connection. As such, returning the local and remote `SocketAddr` with the query is sufficient to uniquely identify the socket.
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.