Commit Graph

65 Commits

Author SHA1 Message Date
Aaron Klotz
47019ce1f1 cmd/tailscaled: pre-load wintun.dll using a fully-qualified path
In corp PR #14970 I updated the installer to set a security mitigation that
always forces system32 to the front of the Windows dynamic linker's search
path.

Unfortunately there are other products out there that, partying like it's
1995, drop their own, older version of wintun.dll into system32. Since we
look there first, we end up loading that old version.

We can fix this by preloading wintun using a fully-qualified path. When
wintun-go then loads wintun, the dynamic linker will hand it the module
that was previously loaded by us.

Fixes #10023, #10025, #10052

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2023-11-02 09:47:21 -06:00
Claire Wang
a56e58c244
util/syspolicy: add read boolean setting (#9592) 2023-09-29 21:27:04 -04:00
Claire Wang
e3d6236606
winutil: refactor methods to get values from registry to also return (#9536)
errors
Updates tailscale/corp#14879

Signed-off-by: Claire Wang <claire@tailscale.com>
2023-09-26 13:15:11 -04:00
Aaron Klotz
37925b3e7a go.mod, cmd/tailscaled, ipn/localapi, util/osdiag, util/winutil, util/winutil/authenticode: add Windows module list to OS-specific logs that are written upon bugreport
* We update wingoes to pick up new version information functionality
  (See pe/version.go in the https://github.com/dblohm7/wingoes repo);
* We move the existing LogSupportInfo code (including necessary syscall
  stubs) out of util/winutil into a new package, util/osdiag, and implement
  the public LogSupportInfo function may be implemented for other platforms
  as needed;
* We add a new reason argument to LogSupportInfo and wire that into
  localapi's bugreport implementation;
* We add module information to the Windows implementation of LogSupportInfo
  when reason indicates a bugreport. We enumerate all loaded modules in our
  process, and for each one we gather debug, authenticode signature, and
  version information.

Fixes #7802

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2023-08-03 11:33:14 -06:00
Aaron Klotz
2aa8299c37 cmd/tailscaled, util/winutil: log our registry keys during tailscaled startup
In order to improve our ability to understand the state of policies and
registry settings when troubleshooting, we enumerate all values in all subkeys.
x/sys/windows does not already offer this, so we need to call RegEnumValue
directly.

For now we're just logging this during startup, however in a future PR I plan to
also trigger this code during a bugreport. I also want to log more than just
registry.

Fixes #8141

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2023-06-01 13:39:17 -06:00
Brad Fitzpatrick
6e967446e4 tsd: add package with System type to unify subsystem init, discovery
This is part of an effort to clean up tailscaled initialization between
tailscaled, tailscaled Windows service, tsnet, and the mac GUI.

Updates #8036

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2023-05-04 14:21:59 -07:00
Mihai Parparita
7330aa593e all: avoid repeated default interface lookups
On some platforms (notably macOS and iOS) we look up the default
interface to bind outgoing connections to. This is both duplicated
work and results in logspam when the default interface is not available
(i.e. when a phone has no connectivity, we log an error and thus cause
more things that we will try to upload and fail).

Fixed by passing around a netmon.Monitor to more places, so that we can
use its cached interface state.

Fixes #7850
Updates #7621

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2023-04-20 15:46:01 -07:00
Will Norris
57a008a1e1 all: pass log IDs as the proper type rather than strings
This change focuses on the backend log ID, which is the mostly commonly
used in the client.  Tests which don't seem to make use of the log ID
just use the zero value.

Signed-off-by: Will Norris <will@tailscale.com>
2023-03-23 11:26:55 -07:00
David Anderson
8b2ae47c31 version: unexport all vars, turn Short/Long into funcs
The other formerly exported values aren't used outside the package,
so just unexport them.

Signed-off-by: David Anderson <danderson@tailscale.com>
2023-02-11 07:29:55 +00:00
Will Norris
71029cea2d all: update copyright and license headers
This updates all source files to use a new standard header for copyright
and license declaration.  Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.

This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.

Updates #6865

Signed-off-by: Will Norris <will@tailscale.com>
2023-01-27 15:36:29 -08:00
Aaron Klotz
53e2010b8a cmd/tailscaled: change Windows implementation to shut down subprocess via closing its stdin
We've been doing a hard kill of the subprocess, which is only safe as long as
both the cli and gui are not running and the subprocess has had the opportunity
to clean up DNS settings etc. If unattended mode is turned on, this is definitely
unsafe.

I changed babysitProc to close the subprocess's stdin to make it shut down, and
then I plumbed a cancel function into the stdin reader on the subprocess side.

Fixes https://github.com/tailscale/corp/issues/5621

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-12-12 12:02:26 -06:00
Jordan Whited
ea5ee6f87c
all: update golang.zx2c4.com/wireguard to github.com/tailscale/wireguard-go (#6692)
This is temporary while we work to upstream performance work in
https://github.com/WireGuard/wireguard-go/pull/64. A replace directive
is less ideal as it breaks dependent code without duplication of the
directive.

Signed-off-by: Jordan Whited <jordan@tailscale.com>
2022-12-09 15:12:20 -08:00
Aaron Klotz
98f21354c6 cmd/tailscaled: add a special command to tailscaled's Windows service for removing WinTun
WinTun is installed lazily by tailscaled while it is running as LocalSystem.
Based upon what we're seeing in bug reports and support requests, removing
WinTun as a lesser user may fail under certain Windows versions, even when that
user is an Administrator.

By adding a user-defined command code to tailscaled, we can ask the service to
do the removal on our behalf while it is still running as LocalSystem.

* The uninstall code is basically the same as it is in corp;
* The command code will be sent as a service control request and is protected by
  the SERVICE_USER_DEFINED_CONTROL access right, which requires Administrator.

I'll be adding follow-up patches in corp to engage this functionality.

Updates https://github.com/tailscale/tailscale/issues/6433

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-12-07 12:12:02 -06:00
Brad Fitzpatrick
3b0de97e07 cmd/tailscaled: unify the two Windows paths + separate IPN server path
tailscaled on Windows had two entirely separate start-up paths for running
as a service vs in the foreground. It's been causing problems for ages.
This unifies the two paths, making them be the same as the path used
for every other platform.

Also, it uses the new async LocalBackend support in ipnserver.Server
so the Server can start serving HTTP immediately, even if tun takes
awhile to come up.

Updates #6535

Change-Id: Icc8c4f96d4887b54a024d7ac15ad11096b5a58cf
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-11-28 13:31:49 -08:00
Brad Fitzpatrick
e8cc78b1af ipn/ipnserver: change Server to let LocalBackend be supplied async
This is step 1 of de-special-casing of Windows and letting the
LocalAPI HTTP server start serving immediately, even while the rest of
the world (notably the Engine and its TUN device) are being created,
which can take a few to dozens of seconds on Windows.

With this change, the ipnserver.New function changes to not take an
Engine and to return immediately, not returning an error, and let its
Run run immediately. If its ServeHTTP is called when it doesn't yet
have a LocalBackend, it returns an error. A TODO in there shows where
a future handler will serve status before an engine is available.

Future changes will:

* delete a bunch of tailscaled_windows.go code and use this new API
* add the ipnserver.Server ServerHTTP handler to await the engine
  being available
* use that handler in the Windows GUI client

Updates #6522

Change-Id: Iae94e68c235e850b112a72ea24ad0e0959b568ee
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-11-28 09:48:33 -08:00
Brad Fitzpatrick
f45106d47c ipn/ipnserver: move Windows-specific code to tailscaled_windows.go
We'll eventually remove it entirely, but for now move get it out of ipnserver
where it's distracting and move it to its sole caller.

Updates #6522

Change-Id: I9c6f6a91bf9a8e3c5ea997952b7c08c81723d447
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-11-26 15:51:22 -08:00
Brad Fitzpatrick
f3ba268a96 ipn/ipnserver: move BabysitProc to tailscaled_windows.go
It's only used by Windows. No need for it to be in ipn/ipnserver,
which we're trying to trim down.

Change-Id: Idf923ac8b6cdae8b5338ec26c16fb8b5ea548071
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-11-25 12:26:38 -08:00
Aaron Klotz
033bd94d4c cmd/tailscaled, wgengine/router: use wingoes/com for COM initialization instead of go-ole
This patch removes the crappy, half-backed COM initialization used by `go-ole`
and replaces that with the `StartRuntime` function from `wingoes`, a library I
have started which, among other things, initializes COM properly.

In particular, we should always be initializing COM to use the multithreaded
apartment. Every single OS thread in the process becomes implicitly initialized
as part of the MTA, so we do not need to concern ourselves as to whether or not
any particular OS thread has initialized COM. Furthermore, we no longer need to
lock the OS thread when calling methods on COM interfaces.

Single-threaded apartments are designed solely for working with Win32 threads
that have a message pump; any other use of the STA is invalid.

Fixes https://github.com/tailscale/tailscale/issues/3137

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-11-24 14:52:23 -06:00
Brad Fitzpatrick
da8def8e13 all: remove old +build tags
The //go:build syntax was introduced in Go 1.17:

https://go.dev/doc/go1.17#build-lines

gofmt has kept the +build and go:build lines in sync since
then, but enough time has passed. Time to remove them.

Done with:

    perl -i -npe 's,^// \+build.*\n,,' $(git grep -l -F '+build')

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-11-04 07:25:42 -07:00
Mihai Parparita
8343b243e7 all: consistently initialize Logf when creating tsdial.Dialers
Most visible when using tsnet.Server, but could have resulted in dropped
messages in a few other places too.

Fixes #5743

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2022-09-30 14:40:56 -07:00
Josh Soref
d4811f11a0 all: fix spelling mistakes
Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>
2022-09-29 13:36:13 -07:00
Aaron Klotz
44f13d32d7 cmd/tailscaled, util/winutil: log Windows service diagnostics when the wintun device fails to install
I added new functions to winutil to obtain the state of a service and all
its depedencies, serialize them to JSON, and write them to a Logf.

When tstun.New returns a wrapped ERROR_DEVICE_NOT_AVAILABLE, we know that wintun
installation failed. We then log the service graph rooted at "NetSetupSvc".
We are interested in that specific service because network devices will not
install if that service is not running.

Updates https://github.com/tailscale/tailscale/issues/5531

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-09-28 16:09:10 -06:00
Brad Fitzpatrick
3562b5bdfa envknob, health: support Synology, show parse errors in status
Updates #5114

Change-Id: I8ac7a22a511f5a7d0dcb8cac470d4a403aa8c817
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-09-17 08:42:41 -07:00
Brad Fitzpatrick
65c24b6334 envknob: generalize Windows tailscaled-env.txt support
ipnserver previously had support for a Windows-only environment
variable mechanism that further only worked when Windows was running
as a service, not from a console.

But we want it to work from tailscaed too, and we want it to work on
macOS and Synology. So move it to envknob, now that envknob can change
values at runtime post-init.

A future change will wire this up for more platforms, and do something
more for CLI flags like --port, which the bug was originally about.

Updates #5114

Change-Id: I9fd69a9a91bb0f308fc264d4a6c33e0cbe352d71
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-09-16 15:30:19 -07:00
Brad Fitzpatrick
74674b110d envknob: support changing envknobs post-init
Updates #5114

Change-Id: Ia423fc7486e1b3f3180a26308278be0086fae49b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-09-15 15:04:02 -07:00
Brad Fitzpatrick
e1309e1323 all: require Go 1.19
Updates #5210

Change-Id: I2e950b4776636b4ea89b6566b60e4a87596a3a43
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-08-02 11:49:01 -07:00
Brad Fitzpatrick
a12aad6b47 all: convert more code to use net/netip directly
perl -i -npe 's,netaddr.IPPrefixFrom,netip.PrefixFrom,' $(git grep -l -F netaddr.)
    perl -i -npe 's,netaddr.IPPortFrom,netip.AddrPortFrom,' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPrefix,netip.Prefix,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPort,netip.AddrPort,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IP\b,netip.Addr,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPv6Raw\b,netip.AddrFrom16,g' $(git grep -l -F netaddr. )
    goimports -w .

Then delete some stuff from the net/netaddr shim package which is no
longer neeed.

Updates #5162

Change-Id: Ia7a86893fe21c7e3ee1ec823e8aba288d4566cd8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-07-25 21:53:49 -07:00
Brad Fitzpatrick
7eaf5e509f net/netaddr: start migrating to net/netip via new netaddr adapter package
Updates #5162

Change-Id: Id7bdec303b25471f69d542f8ce43805328d56c12
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-07-25 16:20:43 -07:00
Brad Fitzpatrick
a9b4bf1535 ipn/ipnserver, cmd/tailscaled: fix peerapi on Windows
We weren't wiring up netstack.Impl to the LocalBackend in some cases
on Windows. This fixes Windows 7 when run as a service.

Updates #4750 (fixes after pull in to corp repo)

Change-Id: I9ce51b797710f2bedfa90545776b7628c7528e99
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-06-03 12:24:47 -07:00
James Tucker
3f686688a6 cmd/tailscaled: fix state path for windows svc
Signed-off-by: James Tucker <james@tailscale.com>
2022-05-26 17:59:50 -07:00
Aaron Klotz
d915e0054c cmd/tailscaled: change Windows service shutdown and add optional event logging
Once a stop request is received and the service updates its status to `svc.StopPending`,
it should continue running *until the shutdown sequence is complete*, and then
return out of `(*ipnService).Execute`, which automatically sends a `svc.Stopped`
notification to Windows.

To make this happen, I changed the loop so that it runs until `doneCh` is
closed, and then returns. I also removed a spurious `svc.StopPending` notification
that the Windows Service Control Manager might be interpreting as a request for
more time to shut down.

Finally, I added some optional logging that sends a record of service notifications
to the Windows event log, allowing us to more easily correlate with any Service
Control Manager errors that are sent to the same log.

Change-Id: I5b596122e5e89c4c655fe747a612a52cb4e8f1e0
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-04-29 15:13:11 -07:00
Brad Fitzpatrick
1db46919ab cmd/tailscaled: make build fail nicely on older Go versions
Due to a bug in Go (golang/go#51778), cmd/go doesn't warn about your
Go version being older than the go.mod's declared Go version in that
case that package loading fails before the build starts, such as when
you use packages that are only in the current version of Go, like our
use of net/netip.

This change works around that Go bug by adding build tags and a
pre-Go1.18-only file that will cause Go 1.17 and earlier to fail like:

    $ ~/sdk/go1.17/bin/go install ./cmd/tailscaled
    # tailscale.com/cmd/tailscaled
    ./required_version.go:11:2: undefined: you_need_Go_1_18_to_compile_Tailscale
    note: module requires Go 1.18

Change-Id: I39f5820de646703e19dde448dd86a7022252f75c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-03-18 08:25:51 -07:00
Maisem Ali
497324ddf6 ipn/store: add common package for instantiating ipn.StateStores
Also move KubeStore and MemStore into their own package.

RELNOTE: tsnet now supports providing a custom ipn.StateStore.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2022-02-28 13:23:33 -08:00
Aaron Klotz
3a74f2d2d7 cmd/tailscaled, util/winutil: add accessor functions for Windows system policies.
This patch adds new functions to be used when accessing system policies,
and revises callers to use the new functions. They first attempt the new
registry path for policies, and if that fails, attempt to fall back to the
legacy path.

We keep non-policy variants of these functions because we should be able to
retain the ability to read settings from locations that are not exposed to
sysadmins for group policy edits.

The remaining changes will be done in corp.

Updates https://github.com/tailscale/tailscale/issues/3584

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2022-02-09 14:58:51 -07:00
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
689426d6bc cmd/tailscaled: log Windows service change requests
And add a little comment.

Change-Id: If0bedf8aefd8d528149548fba829e7a9a8b2e114
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-12-16 12:24:05 -08:00
Brad Fitzpatrick
59f4f33f60 cmd/tailscaled: fix windows logtail integration
I broke it in 1.17.x sometime while rewiring some logs stuff,
mostly in 0653efb092 (but with a handful
of logs-related changes around that time)

Fixes tailscale/corp#3265

Change-Id: Icb5c07412dc6d55f1d9244c5d0b51dceca6a7e34
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-12-14 15:03:37 -08:00
Brad Fitzpatrick
adc5997592 net/tsdial: give netstack a Dialer, start refactoring name resolution
This starts to refactor tsdial.Dialer's name resolution to have
different stages: in-memory MagicDNS vs system resolution. A future
change will plug in ExitDNS resolution.

This also plumbs a Dialer into netstack and unexports the dnsMap
internals.

And it removes some of the async AddNetworkMapCallback usage and
replaces it with synchronous updates of the Dialer's netmap
from LocalBackend, since the LocalBackend has the Dialer too.

Updates #3475

Change-Id: Idcb7b1169878c74f0522f5151031ccbc49fe4cb4
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-12-02 11:33:13 -08:00
Brad Fitzpatrick
c7fb26acdb net/tsdial: also plumb TUN name and monitor into tsdial.Dialer
In prep for moving stuff out of LocalBackend.

Change-Id: I9725aa9c3ebc7275f8c40e040b326483c0340127
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-12-01 10:36:55 -08:00
Brad Fitzpatrick
0653efb092 cmd/tailscaled: remove a redundant date prefix on Windows logs
Change-Id: I28e122d4384697f51a748d67829409276c00b11e
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-11-18 10:23:41 -08:00
Brad Fitzpatrick
e6fbc0cd54 cmd/tailscaled, ipn/ipnserver: refactor ipnserver
More work towards removing the massive ipnserver.Run and ipnserver.Options
and making composable pieces.

Work remains. (The getEngine retry loop on Windows complicates things.)
For now some duplicate code exists. Once the Windows side is fixed
to either not need the retry loop or to move the retry loop into a
custom wgengine.Engine wrapper, then we can unify tailscaled_windows.go
too.

Change-Id: If84d16e3cd15b54ead3c3bb301f27ae78d055f80
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-11-05 15:00:02 -07:00
Brad Fitzpatrick
5dc5bd8d20 cmd/tailscaled, wgengine/netstack: always wire up netstack
Even if not in use. We plan to use it for more stuff later.

(not for iOS or macOS-GUIs yet; only tailscaled)

Change-Id: Idaef719d2a009be6a39f158fd8f57f8cca68e0ee
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-11-01 14:11:30 -07:00
Aaron Klotz
df7899759d cmd/tailscaled: set the correct flag for receiving Windows session change events
This feature wasn't working until I realized that we also need to opt into
the events. MSDN wasn't so generous as to make this easy to deduce.

Updates #2956

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2021-10-06 10:23:55 -06:00
Aaron Klotz
e016eaf410 cmd/tailscaled: conditionally flush Windows DNS cache on SessionChange
For the service, all we need to do is handle the `svc.SessionChange` command.
Upon receipt of a `windows.WTS_SESSION_UNLOCK` event, we fire off a goroutine to flush the DNS cache.
(Windows expects responses to service requests to be quick, so we don't want to do that synchronously.)

This is gated on an integral registry value named `FlushDNSOnSessionUnlock`,
whose value we obtain during service initialization.

(See [this link](https://docs.microsoft.com/en-us/windows/win32/api/winsvc/nc-winsvc-lphandler_function_ex) for information re: handling `SERVICE_CONTROL_SESSIONCHANGE`.)

Fixes #2956

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2021-09-29 09:43:22 -06:00
Brad Fitzpatrick
ed8587f90d wgengine/router: take a link monitor
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>
2021-07-20 13:43:40 -07:00
Brad Fitzpatrick
7f7a81e5ae cmd/tailscaled: add func to create ipnserver.Opts
To unify the Windows service and non-service/non-Windows paths a bit.

And provides a way to make Linux act like Windows for testing.
(notably, for testing the fix to #2137)

One perhaps visible change of this is that tailscaled.exe when run in
cmd.exe/powershell (not as a Windows Service) no longer uses the
"_daemon" autostart key. But in addition to being naturally what falls
out of this change, that's also what Windows users would likely want,
as otherwise the unattended mode user is ignored when the "_daemon"
autostart key is specified. Notably, this would let people debug what
their normally-run-as-a-service tailscaled is doing, even when they're
running in Unattended Mode.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-07-19 15:52:47 -07:00
Maisem Ali
ec52760a3d wgengine/router_windows: support toggling local lan access when using
exit nodes.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2021-06-29 09:22:10 -07:00
Maisem Ali
234cc87f48 cmd/tailscaled: use the wf package instead of wireguard-windows/firewall
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2021-05-17 13:07:25 -07:00
Josh Bleecher Snyder
9360f36ebd all: use lower-case letters at the start of error message
Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
2021-05-04 08:54:50 -07:00
Brad Fitzpatrick
91c9c33036 cmd/tailscaled: don't block ipnserver startup behind engine init on Windows
With this change, the ipnserver's safesocket.Listen (the localhost
tcp.Listen) happens right away, before any synchronous
TUN/DNS/Engine/etc setup work, which might be slow, especially on
early boot on Windows.

Because the safesocket.Listen starts up early, that means localhost
TCP dials (the safesocket.Connect from the GUI) complete successfully
and thus the GUI avoids the MessageBox error. (I verified that
pacifies it, even without a Listener.Accept; I'd feared that Windows
localhost was maybe special and avoided the normal listener backlog).

Once the GUI can then connect immediately without errors, the various
timeouts then matter less, because the backend is no longer trying to
race against the GUI's timeout. So keep retrying on errors for a
minute, or 10 minutes if the system just booted in the past 10
minutes.

This should fix the problem with Windows 10 desktops auto-logging in
and starting the Tailscale frontend which was then showing a
MessageBox error about failing to connect to tailscaled, which was
slow coming up because the Windows networking stack wasn't up
yet. Fingers crossed.

Fixes #1313 (previously #1187, etc)

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-04-20 22:26:27 -07:00