Brad Fitzpatrick
94884d27ff
A utun is a kernel control socket, and recvmsg_x and sendmsg_x work on it just as on UDP sockets. Two things prevented batching by default: xnu's utun driver queues only one packet on the control socket at a time (utun_max_pending_packets defaults to 1), so a batched read could never return more than one, and wireguard-go's Darwin tun.Device reads and writes one packet per call. Wrap the utun device in tstun.New with one that raises the queue depth via the UTUN_OPT_MAX_PENDING_PACKETS socket option and reads and writes batches of up to 128 packets through net/msgx, when msgx is available. Any unexpected error disables the batched path for the life of the device and falls back to the wrapped one. With this, the kernel's TCP stack fills the utun queue under load, wireguard-go encrypts batches, and the connected per-peer sockets send them with one sendmsg_x each. Measured between two M5 Pro Mac minis on a 10 Gbps LAN (iperf3 over Tailscale, 10 second runs, tailscaled CPU seconds per side): before (connected sockets + msgx, per-packet utun) 1.45 Gbps 24.5s / 9.3s with batched utun 4.85 Gbps 25.4s / 25.5s No retransmits in any run. The sender profile is now 19% crypto and most of the rest kernel time in sendmsg_x doing real work; scheduler churn drops from about half of CPU to about a fifth. TS_DEBUG_TUN_BATCH=0 disables it for evaluation. Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com> Change-Id: I2c7e5a9f1b4d8306e7a2c9d5f1b3e8a6c4d7f2b1
Tailscale
Private WireGuard® networks made easy
Overview
This repository contains the majority of Tailscale's open source code.
Notably, it includes the tailscaled daemon and
the tailscale CLI tool. The tailscaled daemon runs on Linux, Windows,
macOS, and to varying degrees
on FreeBSD and OpenBSD. The Tailscale iOS and Android apps use this repo's
code, but this repo doesn't contain the mobile GUI code.
Other Tailscale repos of note:
- the Android app is at https://github.com/tailscale/tailscale-android
- the Synology package is at https://github.com/tailscale/tailscale-synology
- the QNAP package is at https://github.com/tailscale/tailscale-qpkg
- the Chocolatey packaging is at https://github.com/tailscale/tailscale-chocolatey
For background on which parts of Tailscale are open source and why, see https://tailscale.com/opensource/.
Using
We serve packages for a variety of distros and platforms at https://pkgs.tailscale.com.
Other clients
The macOS, iOS, and Windows clients use the code in this repository but additionally include small GUI wrappers. The GUI wrappers on non-open source platforms are themselves not open source.
Building
We always require the latest Go release, currently Go 1.27. (While we build releases with our Go fork, its use is not required.)
go install tailscale.com/cmd/tailscale{,d}
If you're packaging Tailscale for distribution, use build_dist.sh
instead, to burn commit IDs and version info into the binaries:
./build_dist.sh tailscale.com/cmd/tailscale
./build_dist.sh tailscale.com/cmd/tailscaled
If your distro has conventions that preclude the use of
build_dist.sh, please do the equivalent of what it does in your
distro's way, so that bug reports contain useful version information.
Bugs
Please file any issues about this code or the hosted service on the issue tracker.
Contributing
PRs welcome! But please file bugs. Commit messages should reference bugs.
We require Developer Certificate of
Origin
Signed-off-by lines in commits.
See commit-messages.md (or skim git log) for our commit message style.
About Us
Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:
- https://github.com/tailscale/tailscale/graphs/contributors
- https://github.com/tailscale/tailscale-android/graphs/contributors
Legal
WireGuard is a registered trademark of Jason A. Donenfeld.