Link-local addresses on the Tailscale interface are not routable.
Ideally they would be removed, however, a concern exists that the
operating system will attempt to re-add them which would lead to
thrashing.
Setting SkipAsSource attempts to avoid production of packets using the
address as a source in any default behaviors.
Before, in powershell: `ping (hostname)` would ping the link-local
address of the Tailscale interface, and fail.
After: `ping (hostname)` now pings the link-local address on the next
highest priority metric local interface.
Fixes#4647
Signed-off-by: James Tucker <james@tailscale.com>
Fixes#4647
It seems that Windows creates a link-local address for the TUN driver, seemingly
based on the (fixed) adapter GUID. This results in a fixed MAC address, which
for some reason doesn't handle loopback correctly. Given the derived link-local
address is preferred for lookups (thanks LLMNR), traffic which addresses the
current node by hostname uses this broken address and never works.
To address this, we remove the broken link-local address from the wintun adapter.
Signed-off-by: Tom DNetto <tom@tailscale.com>
This reverts commit 8d6793fd70.
Reason: breaks Android build (cgo/pthreads addition)
We can try again next cycle.
Change-Id: I5e7e1730a8bf399a8acfce546a6d22e11fb835d5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
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>
This was just cleanup for an ancient version of Tailscale. Any such machines
have upgraded since then.
Change-Id: Iadcde05b37c2b867f92e02ec5d2b18bf2b8f653a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
A new package can also later record/report which knobs are checked and
set. It also makes the code cleaner & easier to grep for env knobs.
Change-Id: Id8a123ab7539f1fadbd27e0cbeac79c2e4f09751
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
on error.
While debugging a customer issue where the firewallTweaker was failing
the only message we have is `router: firewall: error adding
Tailscale-Process rule: exit status 1` which is not really helpful.
This will help diagnose firewall tweaking failures.
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Allow users of CallbackRouter to supply a GetBaseConfig
implementation. This is expected to be used on Android,
which currently lacks both a) platform support for
Split-DNS and b) a way to retrieve the current DNS
servers.
iOS/macOS also use the CallbackRouter but have platform
support for SplitDNS, so don't need getBaseConfig.
Updates https://github.com/tailscale/tailscale/issues/2116
Updates https://github.com/tailscale/tailscale/issues/988
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
Tailscale 1.18 uses netlink instead of the "ip" command to program the
Linux kernel.
The old way was kept primarily for tests, but this also adds a
TS_DEBUG_USE_IP_COMMAND environment knob to force the old way
temporarily for debugging anybody who might have problems with the
new way in 1.18.
Updates #391
Change-Id: I0236fbfda6c9c05dcb3554fcc27ec0c86456efd9
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
github.com/go-multierror/multierror served us well.
But we need a few feature from it (implement Is),
and it's not worth maintaining a fork of such a small module.
Instead, I did a clean room implementation inspired by its API.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Using temporary netlink fork in github.com/tailscale/netlink until we
get the necessary changes upstream in either vishvananda/netlink
or jsimonetti/rtnetlink.
Updates #391
Change-Id: I6e1de96cf0750ccba53dabff670aca0c56dffb7c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Pull out the list of policy routing rules to a data structure
now shared between the add & delete paths, but to also be shared
by the netlink paths in a future change.
Updates #391
Change-Id: I119ab1c246f141d639006c808b61c585c3d67924
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Anybody using that one old, unreleased version of Tailscale from over
a year ago should've rebooted their machine by now to get various
non-Tailscale security updates. :)
Change-Id: If9e043cb008b20fcd6ddfd03756b3b23a9d7aeb5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This log is quite verbose, it was only to be left in for one
unstable build to help debug a user issue.
This reverts commit 1dd2552032.
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
Intended to help in resolving customer issue with
DNS caching.
We currently exec `ipconfig /flushdns` from two
places:
- SetDNS(), which logs before invoking
- here in router_windows, which doesn't
We'd like to see a positive indication in logs that flushdns
is being run.
As this log is expected to be spammy, it is proposed to
leave this in just long enough to do an unstable 1.13.x build
and then revert it. They won't run an unsigned image that
I build.
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
Prep for #1591 which will need to make Linux's router react to changes
that the link monitor observes.
The router package already depended on the monitor package
transitively. Now it's explicit.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
The route creation for the `tun` device was augmented in #1469 but
didn't account for adding IPv4 vs. IPv6 routes. There are 2 primary
changes as a result:
* Ensure that either `-inet` or `-inet6` was used in the
[`route(8)`](https://man.openbsd.org/route) command
* Use either the `localAddr4` or `localAddr6` for the gateway argument
depending which destination network is being added
The basis for the approach is based on the implementation from
`router_userspace_bsd.go`, including the `inet()` helper function.
Fixes#2048
References #1469
Signed-off-by: Fletcher Nichol <fnichol@nichol.ca>
Pull in the latest version of wireguard-windows.
Switch to upstream wireguard-go.
This requires reverting all of our import paths.
Unfortunately, this has to happen at the same time.
The wireguard-go change is very low risk,
as that commit matches our fork almost exactly.
(The only changes are import paths, CI files, and a go.mod entry.)
So if there are issues as a result of this commit,
the first place to look is wireguard-windows changes.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
On FreeBSD, we add the interface IP as a /48 to work around a kernel
bug, so we mustn't then try to add a /48 route to the Tailscale ULA,
since that will fail as a dupe.
Signed-off-by: David Anderson <danderson@tailscale.com>
