8d6793fd70
Attempt to load the xt_mark kernel module when it is not present. If the load fails, log error information. It may be tempting to promote this failure to an error once it has been in use for some time, so as to avoid reaching an error with the iptables invocation, however, there are conditions under which the two stages may disagree - this change adds more useful breadcrumbs. Example new output from tailscaled running under my WSL2: ``` router: ensure module xt_mark: "/usr/sbin/modprobe xt_mark" failed: exit status 1; modprobe: FATAL: Module xt_mark not found in directory /lib/modules/5.10.43.3-microsoft-standard-WSL2 ``` Background: There are two places to lookup modules, one is `/proc/modules` "old", the other is `/sys/module/` "new". There was query_modules(2) in linux <2.6, alas, it is gone. In a docker container in the default configuration, you would get /proc/modules and /sys/module/ both populated. lsmod may work file, modprobe will fail with EPERM at `finit_module()` for an unpriviliged container. In a priviliged container the load may *succeed*, if some conditions are met. This condition should be avoided, but the code landing in this change does not attempt to avoid this scenario as it is both difficult to detect, and has a very uncertain impact. In an nspawn container `/proc/modules` is populated, but `/sys/module` does not exist. Modern `lsmod` versions will fail to gather most module information, without sysfs being populated with module information. In WSL2 modules are likely missing, as the in-use kernel typically is not provided by the distribution filesystem, and WSL does not mount in a module filesystem of its own. Notably the WSL2 kernel supports iptables marks without listing the xt_mark module in /sys/module, and /proc/modules is empty. On a recent kernel, we can ask the capabilities system about SYS_MODULE, that will help to disambiguate between the non-privileged container case and just being root. On older kernels these calls may fail. Update #4329 Signed-off-by: James Tucker <james@tailscale.com>
Tailscale
Private WireGuard® networks made easy
Overview
This repository contains all the open source Tailscale client code and
the tailscaled daemon and tailscale CLI tool. The tailscaled
daemon runs on Linux, Windows and macOS, and to varying degrees on FreeBSD, OpenBSD, and Darwin. (The Tailscale iOS and Android apps use this repo's code, but this repo doesn't contain the mobile GUI code.)
The Android app is at https://github.com/tailscale/tailscale-android
The Synology package is at https://github.com/tailscale/tailscale-synology
Using
We serve packages for a variety of distros 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 that are not open source.
Building
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.
We only guarantee to support the latest Go release and any Go beta or release candidate builds (currently Go 1.18) in module mode. It might work in earlier Go versions or in GOPATH mode, but we're making no effort to keep those working.
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.
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.