Commit Graph

24 Commits

Author SHA1 Message Date
Aaron Klotz
4baf34cf25 net/dns: set appropriate Windows registry values to prevent it from sending DNS changes concerning our interface to AD domain controllers.
We do this unconditionally inside SetDNS such that the values are always set
before we make any other changes to DNS configurations.

It should not be harmful for the settings to remain even when other DNS
settings are cleared out (since they only affect our network interface).

See https://docs.microsoft.com/en-us/troubleshoot/windows-server/networking/configure-dns-dynamic-updates-windows-server-2003 for details about the registry value.

Fixes https://github.com/tailscale/tailscale/issues/4829

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-06-24 11:41:33 -06:00
Aaron Klotz
8cdfd12977 net/dns: update Windows split DNS settings to work alongside other NRPT entries set by group policy.
When there are group policy entries for the NRPT that do not belong to Tailscale,
we recognize that we need to add ourselves to group policy and use that registry
key instead of the local one. We also refresh the group policy settings as
necessary to ensure that our changes take effect immediately.

Fixes https://github.com/tailscale/tailscale/issues/4607

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-06-23 15:42:22 -06:00
Aaron Klotz
b005b79236 net/dns, paths, util/winutil: change net/dns/windowsManager NRPT management to support more than 50 domains.
AFAICT this isn't documented on MSDN, but based on the issue referenced below,
NRPT rules are not working when a rule specifies > 50 domains.

This patch modifies our NRPT rule generator to split the list of domains
into chunks as necessary, and write a separate rule for each chunk.

For compatibility reasons, we continue to use the hard-coded rule ID, but
as additional rules are required, we generate new GUIDs. Those GUIDs are
stored under the Tailscale registry path so that we know which rules are ours.

I made some changes to winutils to add additional helper functions in support
of both the code and its test: I added additional registry accessors, and also
moved some token accessors from paths to util/winutil.

Fixes https://github.com/tailscale/coral/issues/63

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-05-27 14:56:09 -06:00
Brad Fitzpatrick
41fd4eab5c envknob: add new package for all the strconv.ParseBool(os.Getenv(..))
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>
2022-01-24 11:51:23 -08:00
Brad Fitzpatrick
8df3fa4638 net/dns: make WSL network configuration opt-in for now
Tailscale seems to be breaking WSL configurations lately.  Until we
understand what changed, turn off Tailscale's involvement by default
and make it opt-in.

Updates #2815

Change-Id: I9977801f8debec7d489d97761f74000a4a33f71b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-01-11 10:10:21 -08:00
Denton Gentry
260b85458c net/dns: correct log message.
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
2021-08-03 13:58:29 -07:00
David Crawshaw
6b9f8208f4 net/dns: do not run wsl.exe as LocalSystem
It doesn't work. It needs to run as the user.

	https://github.com/microsoft/WSL/issues/4803

The mechanism for doing this was extracted from:

	https://web.archive.org/web/20101009012531/http://blogs.msdn.com/b/winsdk/archive/2009/07/14/launching-an-interactive-process-from-windows-service-in-windows-vista-and-later.aspx

While here, we also reclaculate WSL distro set on SetDNS.
This accounts for:

	1. potential inability to access wsl.exe on startup
	2. WSL being installed while Tailscale is running
	3. A new WSL distrobution being installed

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
2021-06-30 10:11:33 -07:00
David Crawshaw
1147c7fd4f net/dns: set WSL /etc/resolv.conf
We also have to make a one-off change to /etc/wsl.conf to stop every
invocation of wsl.exe clobbering the /etc/resolv.conf. This appears to
be a safe change to make permanently, as even though the resolv.conf is
constantly clobbered, it is always the same stable internal IP that is
set as a nameserver. (I believe the resolv.conf clobbering predates the
MS stub resolver.)

Tested on WSL2, should work for WSL1 too.

Fixes #775

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
2021-06-28 14:18:15 -07:00
David Anderson
084d48d22d net/dns: always proxy through quad-100 on windows 8.1.
Windows 8.1 incorrectly handles search paths on an interface with no
associated resolver, so we have to provide a full primary DNS config
rather than use Windows 8.1's nascent-but-present NRPT functionality.

Fixes #2237.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-06-23 17:50:19 -07:00
David Anderson
44c2b7dc79 net/dns: on windows, skip site-local v6 resolvers.
Further refinement for tailscale/corp#1662.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-27 18:24:54 -07:00
David Anderson
854d5d36a1 net/dns: return error from NewOSManager, use it to initialize NM.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-12 15:51:37 -07:00
David Anderson
1a371b93be util/dnsname: add FQDN type, use throughout codebase.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 17:58:13 -07:00
David Anderson
4a64d2a603 net/dns: some post-review cleanups.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-07 15:40:31 -07:00
David Anderson
68f76e9aa1 net/dns: add GetBaseConfig to OSConfigurator interface.
Part of #953, required to make split DNS work on more basic
platforms.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-07 15:40:31 -07:00
David Anderson
e0e677a8f6 net/dns: split out search domains and match domains in OSConfig.
It seems that all the setups that support split DNS understand
this distinction, and it's an important one when translating
high-level configuration.

Part of #953.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-06 15:27:09 -07:00
David Anderson
a8dcda9c9a net/dns: start of compat hacks for Windows 7.
Correctly reports that Win7 cannot do split DNS, and has a helper to
discover the "base" resolvers for the system.

Part of #953

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-06 15:27:09 -07:00
David Anderson
3e915ac783 net/dns: implement OS-level split DNS for Windows.
Part of #953.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-05 22:53:10 -07:00
David Anderson
de6dc4c510 net/dns: add a Primary field to OSConfig.
Currently ignored.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-05 13:05:47 -07:00
David Anderson
b2a597b288 net/dns: rename Set to SetDNS in OSConfigurator.
wgengine/router.CallbackRouter needs to support both the Router
and OSConfigurator interfaces, so the setters can't both be called
Set.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-05 10:55:35 -07:00
David Anderson
4c61ebacf4 wgengine: move DNS configuration out of wgengine/router.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-05 10:55:35 -07:00
David Anderson
befd8e4e68 net/dns: replace managerImpl with OSConfigurator in code.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-02 02:34:40 -07:00
David Anderson
8af9d770cf net/dns: rename Config to OSConfig.
Making way for a new higher level config struct.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-02 00:59:44 -07:00
David Anderson
fcfc0d3a08 net/dns: remove ManagerConfig, pass relevant args directly.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-01 23:26:52 -07:00
David Anderson
9f7f2af008 wgengine/router/dns: move to net/dns.
Preparation for merging the APIs and whatnot.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-03-25 16:25:30 -07:00