274cc86557
This brings us one step closer to completing #6140. In Firezone, users can define custom upstream DNS servers that take priority over system-defined DNS servers. The IPs of these servers could also be resources, meaning the DNS queries must be sent through the WireGuard tunnel to the gateway. For UDP DNS queries, that is easy because each query is only a single packet. For TCP DNS queries, we need to have a dedicated TCP-capable DNS server that parses all incoming queries. If they are required to be forwarded to the gateway, we then need a TCP-capable DNS client that can send them to the actual upstream DNS server. This PR implements such a DNS client. The design is tailored for what we need in `connlib`: We maintain a permanent TCP connection to each upstream DNS server and send queries to them. Most likely, users will only have a handful of DNS servers defined. TCP requires a three-way handshake before any application data can be sent, maintaining a connection should therefore greatly improve DNS resolution latency. DNS resolvers are encouraged to keep TCP connections open but may close them if they run out of resources. We only re-connect once we have more queries to send in order to not spam the resolver with connections. Resolves: #7000. --------- Signed-off-by: Thomas Eizinger <thomas@eizinger.io>
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
benchprofile. sudo perf 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.