9cce4fd637
When we receive an inbound packet from the TUN device on the Gateway, we make a lookup in the NAT table to see if it needs to be translated back to a DNS proxy IP. At present, non-existence of such a NAT entry results in the packet being sent entirely unmodified because that is what needs to happen for CIDR resources. Whilst that is important, the same code path is currently being executed for DNS resources whose NAT session expired! Those packets should be dropped instead which is what we do with this PR. To differentiate between not having a NAT session at all or whether a previous one existed but is expired now, we keep around all previous "outside" tuples of NAT sessions around. Those are only very small in their memory-footprint. The entire NAT table is scoped to a connection to the given peer and will thus eventually freed once the peer disconnects. This allows us to reliably and cheaply detect, whether a packet is using an expired NAT session. This check must be cheap because all traffic of CIDR resources and the Internet resource needs to perform this check such that we know that they don't have to be translated. This might be the source of some of the "Source not allowed" errors we have been seeing in client logs.
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.