Thomas Eizinger 194eebd164 fix(connlib): de-prioritise timeout handling (#6077)
`connlib`'s event loop performs work in a very particular order:

1. Local buffers like IP, UDP and DNS packets are emptied.
2. Time-sensitive tasks, if any, are performed.
3. New UDP packets are processed.
4. New IP packets (from the TUN device) are processed.

This priority ensures we don't accept more work (i.e. new packets) until
we have finished processing existing work. As a result, we can keep
local buffers small and processing latencies low.

I am not completely confident on the issue of #6067 but if the busy-loop
originates from a bad timer, then the above priority means we never get
to the part where we read new UDP or IP packets and components such a
`PhoenixChannel` - which operate outside of `connlib'`s event loop -
don't get any CPU time.

A naive fix for this problem is to just de-prioritise the polling of the
timer within `Io::poll`. I say naive because without additional changes,
this could delay the processing of time-sensitive tasks on a very busy
client / gateway where packets are constantly arriving and thus we
never[^1] reach the part where the timer gets polled.

To fix this, we make two distinct changes:

1. We pro-actively break from `connlib'`s event loop every 5000
iterations. This ensures that even on a very busy system, other
components like the `PhoenixChannel` get a chance to do _some_ work once
in a while.
2. In case we force-yield from the event loop, we call `handle_timeout`
and immediately schedule a new wake-up. This ensures time does advance
in regular intervals as well and we don't get wrongly suspended by the
runtime.

These changes don't prevent any timer-loops by themselves. With a
timer-loop, we still busy-loop for 5000 iterations and thus
unnecessarily burn through some CPU cycles. The important bit however is
that we stay operational and can accept packets and portal messages. Any
of them might change the state such that the timer value changes, thus
allowing `connlib` to self-heal from this loop.

Fixes: #6067.

[^1]: This is an assumption based on the possible control flow. In
practise, I believe that reading from the sockets or the TUN device is a
much slower operation than processing the packets. Thus, we should
eventually hit the the timer path too.
2024-07-29 22:16:10 +00:00
2024-07-26 13:22:55 -06:00
2024-02-27 23:56:46 +00:00
2024-02-27 23:56:46 +00:00

firezone logo

A modern alternative to legacy VPNs.


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Note: The main branch tracks Firezone 1.x. See the legacy branch if you're looking for Firezone 0.7.

Read the 1.0 announcement for more.


Overview

Firezone is an open source platform to securely manage remote access for any-sized organization. Unlike most VPNs, Firezone takes a granular, least-privileged approach to access management with group-based policies that control access to individual applications, entire subnets, and everything in between.

architecture

Features

Firezone is:

  • Fast: Built on WireGuard® to be 3-4 times faster than OpenVPN.
  • Scalable: Deploy two or more gateways for automatic load balancing and failover.
  • Private: Peer-to-peer, end-to-end encrypted tunnels prevent packets from routing through our infrastructure.
  • Secure: Zero attack surface thanks to Firezone's holepunching tech which establishes tunnels on-the-fly at the time of access.
  • Open: Our entire product is open-source, allowing anyone to audit the codebase.
  • Flexible: Authenticate users via email, Google Workspace, Okta, Entra ID, or OIDC and sync users and groups automatically.
  • Simple: Deploy gateways and configure access in minutes with a snappy admin UI.

Firezone is not:

  • A tool for creating bi-directional mesh networks
  • A full-featured router or firewall
  • An IPSec or OpenVPN server

Contents of this repository

This is a monorepo containing the full Firezone product, marketing website, and product documentation, organized as follows:

Quickstart

The quickest way to get started with Firezone is to sign up for an account at https://app.firezone.dev/sign_up.

Once you've signed up, follow the instructions in the welcome email to get started.

Frequently asked questions (FAQ)

Can I self-host Firezone?

Our license won't stop you from self-hosting the entire Firezone product top to bottom, but our internal APIs are changing rapidly so we can't meaningfully support self-hosting Firezone in production at this time.

If you're feeling especially adventurous and want to self-host Firezone for educational or hobby purposes, follow the instructions to spin up a local development environment in CONTRIBUTING.md.

The latest published clients (on App Stores and on releases) are only guaranteed to work with the managed version of Firezone and may not work with a self-hosted portal built from this repository. This is because Apple and Google can sometimes delay updates to their app stores, and so the latest published version may not be compatible with the tip of main from this repository.

Therefore, if you're experimenting with self-hosting Firezone, you will probably want to use clients you build and distribute yourself as well.

See the READMEs in the following directories for more information on building each client:

How long will 0.7 be supported until?

Firezone 0.7 is currently end-of-life and has stopped receiving updates as of January 31st, 2024. It will continue to be available indefinitely from the legacy branch of this repo under the Apache 2.0 license.

How much does it cost?

We offer flexible per-seat monthly and annual plans for the cloud-managed version of Firezone, with optional invoicing for larger organizations. See our pricing page for more details.

Those experimenting with self-hosting can use Firezone for free without feature or seat limitations, but we can't provide support for self-hosted installations at this time.

Documentation

Additional documentation on general usage, troubleshooting, and configuration can be found at https://www.firezone.dev/kb.

Get Help

If you're looking for help installing, configuring, or using Firezone, check our community support options:

  1. Discussion Forums: Ask questions, report bugs, and suggest features.
  2. Join our Discord Server: Join live discussions, meet other users, and chat with the Firezone team.
  3. Open a PR: Contribute a bugfix or make a contribution to Firezone.

If you need help deploying or maintaining Firezone for your business, consider contacting our sales team to speak with a Firezone expert.

Star History

Star History Chart

Developing and Contributing

See CONTRIBUTING.md.

Security

See SECURITY.md.

License

Portions of this software are licensed as follows:

  • All content residing under the "elixir/" directory of this repository, if that directory exists, is licensed under the "Elastic License 2.0" license defined in "elixir/LICENSE".
  • All third party components incorporated into the Firezone Software are licensed under the original license provided by the owner of the applicable component.
  • Content outside of the above mentioned directories or restrictions above is available under the "Apache 2.0 License" license as defined in "LICENSE".

WireGuard® is a registered trademark of Jason A. Donenfeld.

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