mirror of https://github.com/outbackdingo/firezone.git synced 2026-01-27 10:18:54 +00:00

Files

Thomas Eizinger 301d2137e5 refactor(windows): share src IP cache across UDP sockets (#9976 )

When looking through customer logs, we see a lot of "Resolved best route
outside of tunnel" messages. Those get logged every time we need to
rerun our re-implementation of Windows' weighting algorithm as to which
source interface / IP a packet should be sent from.

Currently, this gets cached in every socket instance so for the
peer-to-peer socket, this is only computed once per destination IP.
However, for DNS queries, we make a new socket for every query. Using a
new source port DNS queries is recommended to avoid fingerprinting of
DNS queries. Using a new socket also means that we need to re-run this
algorithm every time we make a DNS query which is why we see this log so
often.

To fix this, we need to share this cache across all UDP sockets. Cache
invalidation is one of the hardest problems in computer science and this
instance is no different. This cache needs to be reset every time we
roam as that changes the weighting of which source interface to use.

To achieve this, we extend the `SocketFactory` trait with a `reset`
method. This method is called whenever we roam and can then reset a
shared cache inside the `UdpSocketFactory`. The "source IP resolver"
function that is passed to the UDP socket now simply accesses this
shared cache and inserts a new entry when it needs to resolve the IP.

As an added benefit, this may speed up DNS queries on Windows a bit
(although I haven't benchmarked it). It should certainly drastically
reduce the amount of syscalls we make on Windows.

2025-07-24 01:36:53 +00:00

docs

refactor(linux-client): replace client-tunnel with headless-client which is the same thing (#4516 )

2024-04-10 22:01:55 +00:00

src

refactor(windows): share src IP cache across UDP sockets (#9976 )

2025-07-24 01:36:53 +00:00

Cargo.toml

ci: publish headless 1.5.1 (#9791 )

2025-07-05 08:18:14 +00:00

README.md

fix(docs): use sha256sum over sha256 (#9690 )

2025-06-27 20:08:41 +00:00

README.md

headless-client

This crate acts as the CLI / headless Client, and the privileged tunnel service for the GUI Client, for both Linux and Windows.

It is built as:

headless-client to act as the Linux / Windows headless Client
firezone-headless-client to act as the Linux tunnel service, Windows headless Client, or Windows tunnel service

In general, the brand name should be part of the file name, but the OS name should not be.

Running

To run the headless Client:

Generate a new Service account token from the "Actors -> Service Accounts" section of the admin portal and save it in your secrets manager. The Firezone Linux client requires a service account at this time.
Ensure /etc/dev.firezone.client/token is only readable by root (i.e. chmod 400)
Ensure /etc/dev.firezone.client/token contains the Service account token. The Client needs this before it can start
Set FIREZONE_ID to a unique string to identify this client in the portal, e.g. export FIREZONE_ID=$(head -c 32 /dev/urandom | sha256sum | cut -d' ' -f1). The client requires this variable at startup. We recommend this to be a 64 character hex string.

Set LOG_DIR to a suitable directory for writing logs

export LOG_DIR=/tmp/firezone-logs
mkdir $LOG_DIR

Now, you can start the client with:

./firezone-headless-client standalone

If you're running as an unprivileged user, you'll need the CAP_NET_ADMIN capability to open /dev/net/tun. You can add this to the client binary with:

sudo setcap 'cap_net_admin+eip' /path/to/firezone-headless-client

Building

Assuming you have Rust installed, you can build the headless Client with:

cargo build --release -p firezone-headless-client

The binary will be in target/release/firezone-headless-client

The release on Github are built with musl. To build this way, use:

rustup target add x86_64-unknown-linux-musl
sudo apt-get install musl-tools
cargo build --release -p headless-client --target x86_64-unknown-linux-musl

Files

/etc/dev.firezone.client/token - The service account token, provided by the human administrator. Must be owned by root and have 600 permissions (r/w by owner, nobody else can read) If present, the tunnel will ignore any GUI Client and run as a headless Client. If absent, the tunnel will wait for commands from a GUI Client
/usr/bin/firezone-headless-client - The tunnel binary. This must run as root so it can modify the system's DNS settings. If DNS is not needed, it only needs CAP_NET_ADMIN.
/usr/lib/systemd/system/firezone-headless-client.service - A systemd service unit, installed by the deb package.
/var/lib/dev.firezone.client/config/firezone-id - The device ID, unique across an organization. The tunnel will generate this if it's not present.