Commit Graph

341 Commits (048cb61dd07ec2bbf7fafb28a605fce5dd61234d)

Author SHA1 Message Date
Aaron Klotz 9687f3700d net/dns: deal with Windows wsl.exe hangs
Despite the fact that WSL configuration is still disabled by default, we
continue to log the machine's list of WSL distros as a diagnostic measure.

Unfortunately I have seen the "wsl.exe -l" command hang indefinitely. This patch
adds a (more than reasonable) 10s timeout to ensure that tailscaled does not get
stuck while executing this operation.

I also modified the Windows implementation of NewOSConfigurator to do the
logging asynchronously, since that information is not required in order to
continue starting up.

Fixes #7476

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2 years ago
Maisem Ali 1a30b2d73f all: use tstest.Replace more
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Mihai Parparita 9cb332f0e2 sockstats: instrument networking code paths
Uses the hooks added by tailscale/go#45 to instrument the reads and
writes on the major code paths that do network I/O in the client. The
convention is to use "<package>.<type>:<label>" as the annotation for
the responsible code path.

Enabled on iOS, macOS and Android only, since mobile platforms are the
ones we're most interested in, and we are less sensitive to any
throughput degradation due to the per-I/O callback overhead (macOS is
also enabled for ease of testing during development).

For now just exposed as counters on a /v0/sockstats PeerAPI endpoint.

We also keep track of the current interface so that we can break out
the stats by interface.

Updates tailscale/corp#9230
Updates #3363

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
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>
2 years ago
Mihai Parparita 0e3fb91a39 net/dns/resolver: remove maxDoHInFlight
It was originally added to control memory use on iOS (#2490), but then
was relaxed conditionally when running on iOS 15 (#3098). Now that we
require iOS 15, there's no need for the limit at all, so simplify back
to the original state.

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Andrew Dunham 880a41bfcc net/dns/resolver: add envknob to debug exit node DNS queries on on Windows
Add the envknob TS_DEBUG_EXIT_NODE_DNS_NET_PKG, which enables more
verbose debug logging when calling the handleExitNodeDNSQueryWithNetPkg
function. This function is currently only called on Windows and Android.

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ieb3ca7b98837d7dc69cd9ca47609c1c52e3afd7b
2 years ago
Brad Fitzpatrick b1248442c3 all: update to Go 1.20, use strings.CutPrefix/Suffix instead of our fork
Updates #7123
Updates #5309

Change-Id: I90bcd87a2fb85a91834a0dd4be6e03db08438672
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
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>
2 years ago
Brad Fitzpatrick 3addcacfe9 net/dns: fix recently added URL scheme from http to https
I typoed/brainoed in the earlier 3582628691

Change-Id: Ic198a6f9911f195d9da9fc5259b5784a4b15e5e3
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 3582628691 net/dns/resolvconffile: link to FAQ about resolv.conf being overwritten
Add link to new http://tailscale.com/s/resolvconf-overwrite page,
added in tailscale/tailscale-www#2243

Change-Id: I9718399487f2ed18bf1a112581fd168aea30f232
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Tom DNetto 673b3d8dbd net/dns,userspace: remove unused DNS paths, normalize query limit on iOS
With a42a594bb3, iOS uses netstack and
hence there are no longer any platforms which use the legacy MagicDNS path. As such, we remove it.

We also normalize the limit for max in-flight DNS queries on iOS (it was 64, now its 256 as per other platforms).
It was 64 for the sake of being cautious about memory, but now we have 50Mb (iOS-15 and greater) instead of 15Mb
so we have the spare headroom.

Signed-off-by: Tom DNetto <tom@tailscale.com>
2 years ago
Brad Fitzpatrick ea70aa3d98 net/dns/resolvconffile: fix handling of multiple search domains
Fixes #6875

Change-Id: I57eb9312c9a1c81792ce2b5a0a0f254213b05df2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Andrew Dunham 0372e14d79 net/dns: bump DNS-over-TCP size limit to 4k
We saw a few cases where we hit this limit; bumping to 4k seems
relatively uncontroversial.

Change-Id: I218fee3bc0d2fa5fde16eddc36497a73ebd7cbda
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
2 years ago
Andrew Dunham 3f4d51c588 net/dns: don't send on closed channel when message too large
Previously, if a DNS-over-TCP message was received while there were
existing queries in-flight, and it was over the size limit, we'd close
the 'responses' channel. This would cause those in-flight queries to
send on the closed channel and panic.

Instead, don't close the channel at all and rely on s.ctx being
canceled, which will ensure that in-flight queries don't hang.

Fixes #6725

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I8267728ac37ed7ae38ddd09ce2633a5824320097
2 years ago
Brad Fitzpatrick ca08e316af util/endian: delete package; use updated josharian/native instead
See josharian/native#3

Updates golang/go#57237

Change-Id: I238c04c6654e5b9e7d9cfb81a7bbc5e1043a84a2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali 99aa335923 net/dns: [linux] log and add metric for dnsMode
I couldn't find any logs that indicated which mode it was running in so adding that.
Also added a gauge metric for dnsMode.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Andrew Dunham ec790e58df net/dns: retry overwriting hosts file on Windows
Updates #5753

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I60f81bd3325d5ba5383b947c7a7aaa5b14e460f6
2 years ago
Mihai Parparita 33520920c3 all: use strs.CutPrefix and strs.CutSuffix more
Updates places where we use HasPrefix + TrimPrefix to use the combined
function.

Updates #5309

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Aaron Klotz 41e1d336cc net/dns: change windows DNS manager to use pointer receiver
This is safer given that we need to close the NRPT database.

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2 years ago
Brad Fitzpatrick 90bd74fc05 net/dns: add a health warning when Linux /etc/resolv.conf is overwritten
Change-Id: I925b4d904bc7ed920bc5afee11e6dcb2ffc2fbfd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 001f482aca net/dns: make "direct" mode on Linux warn on resolv.conf fights
Run an inotify goroutine and watch if another program takes over
/etc/inotify.conf. Log if so.

For now this only logs. In the future I want to wire it up into the
health system to warn (visible in "tailscale status", etc) about the
situation, with a short URL to more info about how you should really
be using systemd-resolved if you want programs to not fight over your
DNS files on Linux.

Updates #4254 etc etc

Change-Id: I86ad9125717d266d0e3822d4d847d88da6a0daaa
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 66b4a363bd net/dns/resolver: add yet another 4via6 DNS form that's hopefully more robust
$ dig +short @100.100.100.100 aaaa 10-2-5-3-via-7.foo-bar.ts.net
fd7a:115c:a1e0:b1a:0:7:a02:503

$ dig +short @100.100.100.100 aaaa 10-2-5-3-via-7
fd7a:115c:a1e0:b1a:0:7:a02:503

$ ping 10-2-5-3-via-7
PING 10-2-5-3-via-7(fd7a:115c:a1e0:b1a:0:7:a02:503 (fd7a:115c:a1e0:b1a:0:7:a02:503)) 56 data bytes
...

Change-Id: Ice8f954518a6a2fca8b2c04da7f31f61d78cdec4
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
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>
2 years ago
Anton Tolchanov e25ab75795 net/dns: getting base DNS config is not supported on macOS
Instead of returning a custom error, use ErrGetBaseConfigNotSupported
that seems to be intended for this use case. This fixes DNS resolution
on macOS clients compiled from source.

Signed-off-by: Anton Tolchanov <anton@tailscale.com>
2 years ago
Andrew Dunham e966f024b0 net/dns: print systemd-resolved ResolvConfMode
The ResolvConfMode property is documented to return how systemd-resolved
is currently managing /etc/resolv.conf. Include that information in the
debug line, when available, to assist in debugging DNS issues.

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I1ae3a257df1d318d0193a8c7f135c458ec45093e
2 years ago
Maisem Ali 3555a49518 net/dns: always attempt to read the OS config on macOS/iOS
Also reconfigure DNS on iOS/macOS on link changes.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
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>
2 years ago
Josh Soref d4811f11a0 all: fix spelling mistakes
Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>
2 years ago
Brad Fitzpatrick bb7be74756 net/dns/publicdns: permit more NextDNS profile bits in its IPv6 suffix
I brain-o'ed the math earlier. The NextDNS prefix is /32 (actually
/33, but will guarantee last bit is 0), so we have 128-32 = 96 bits
(12 bytes) of config/profile ID that we can extract. NextDNS doesn't
currently use all those, but might.

Updates #2452

Change-Id: I249bd28500c781e45425fd00fd3f46893ae226a2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Andrew Dunham a5fab23e8f
net/dns: format OSConfig correctly with no pointers (#5766)
Fixes tailscale/tailscale#5669

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
2 years ago
Eng Zer Jun f0347e841f refactor: move from io/ioutil to io and os packages
The io/ioutil package has been deprecated as of Go 1.16 [1]. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.

Reference: https://golang.org/doc/go1.16#ioutil
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
2 years ago
Brad Fitzpatrick 74674b110d envknob: support changing envknobs post-init
Updates #5114

Change-Id: Ia423fc7486e1b3f3180a26308278be0086fae49b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Mihai Parparita 82e82d9b7a net/dns/resolver: remove unused responseTimeout constant
Timeout is now enforced elsewhere, see discussion in https://github.com/tailscale/tailscale/pull/4408#discussion_r970092333.

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
nyghtowl 0f16640546 net/dns: fix fmt error on Revert print
Fixes #5619

Signed-off-by: nyghtowl <warrick@tailscale.com>
2 years ago
Brad Fitzpatrick 708b7bff3d net/dns/publicdns: also support NextDNS DoH query parameters
The plan has changed. Doing query parameters rather than path +
heades. NextDNS added support for query parameters.

Updates #2452

Change-Id: I4783c0a06d6af90756d9c80a7512644ba702388c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick e7376aca25 net/dns/resolver: set DNS-over-HTTPS Accept and User-Agent header on requests
Change-Id: I14b821771681e70405a507f43229c694159265ff
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick c14361e70e net/dns/publicdns: support NextDNS DoH URLs with path parameters
Updates #2452

Change-Id: I0f1c34cc1672e87e7efd0adfe4088724dd0de3ed
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 2aade349fc net/dns, types/dnstypes: update some comments, tests for DoH
Clarify & verify that some DoH URLs can be sent over tailcfg
in some limited cases.

Updates #2452

Change-Id: Ibb25db77788629c315dc26285a1059a763989e24
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 58abae1f83 net/dns/{publicdns,resolver}: add NextDNS DoH support
NextDNS is unique in that users create accounts and then get
user-specific DNS IPs & DoH URLs.

For DoH, the customer ID is in the URL path.

For IPv6, the IP address includes the customer ID in the lower bits.

For IPv4, there's a fragile "IP linking" mechanism to associate your
public IPv4 with an assigned NextDNS IPv4 and that tuple maps to your
customer ID.

We don't use the IP linking mechanism.

Instead, NextDNS is DoH-only. Which means using NextDNS necessarily
shunts all DNS traffic through 100.100.100.100 (programming the OS to
use 100.100.100.100 as the global resolver) because operating systems
can't usually do DoH themselves.

Once it's in Tailscale's DoH client, we then connect out to the known
NextDNS IPv4/IPv6 anycast addresses.

If the control plane sends the client a NextDNS IPv6 address, we then
map it to the corresponding NextDNS DoH with the same client ID, and
we dial that DoH server using the combination of v4/v6 anycast IPs.

Updates #2452

Change-Id: I3439d798d21d5fc9df5a2701839910f5bef85463
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 9bd9f37d29 go.mod: bump wireguard/windows, which moves to using net/netip
Updates #5162

Change-Id: If99a3f0000bce0c01bdf44da1d513f236fd7cdf8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 9f6c8517e0 net/dns: set OS DNS to 100.100.100.100 for route-less ExtraRecords [cap 41]
If ExtraRecords (Hosts) are specified without a corresponding split
DNS route and global DNS is specified, then program the host OS DNS to
use 100.100.100.100 so it can blend in those ExtraRecords.

Updates #1543

Change-Id: If49014a5ecc8e38978ff26e54d1f74fe8dbbb9bc
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Maisem Ali 68d9d161f4 net/dns: [win] fix regression in disableDynamicUpdate
Somehow I accidentally set the wrong registry value here.
It should be DisableDynamicUpdate=1 and not EnableDNSUpdate=0.

This is a regression from 545639e.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Nahum Shalman 214242ff62 net/dns/publicdns: Add Mullvad DoH
See https://mullvad.net/en/help/dns-over-https-and-dns-over-tls/

The Mullvad DoH servers appear to only speak HTTP/2 and
the use of a non-nil DialContext in the http.Transport
means that ForceAttemptHTTP2 must be set to true to be
able to use them.

Signed-off-by: Nahum Shalman <nahamu@gmail.com>
2 years ago
Maisem Ali 9197dd14cc net/dns: [win] add MagicDNS entries to etc/hosts
This works around the 2.3s delay in short name lookups when SNR is
enabled.
C:\Windows\System32\drivers\etc\hosts file. We only add known hosts that
match the search domains, and we populate the list in order of
Search Domains so that our matching algorithm mimics what Windows would
otherwise do itself if SNR was off.

Updates #1659

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 25865f81ee net/dns: disable NetBIOS on Tailscale interfaces
Like LLMNR, NetBIOS also adds resolution delays and we don't support it
anyway so just disable it on the interface.

Updates #1659

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 545639ee44 util/winutil: consolidate interface specific registry keys
Code movement to allow reuse in a follow up PR.

Updates #1659

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 1cff719015 net/dns: [win] respond with SERVFAIL queries when no resolvers
Currently we forward unmatched queries to the default resolver on
Windows. This results in duplicate queries being issued to the same
resolver which is just wasted.

Updates #1659

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 3bb57504af net/dns/resolver: add comments clarifying nil error returns
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 4497bb0b81 net/dns/resolver: return SERVFAIL when no upstream resolvers set
Otherwise we just keep looping over the same thing again and again.

```
dns udp query: upstream nameservers not set
dns udp query: upstream nameservers not set
dns udp query: upstream nameservers not set
```

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali a9f6cd41fd all: use syncs.AtomicValue
Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Maisem Ali 9bb5a038e5 all: use atomic.Pointer
Also add some missing docs.

Signed-off-by: Maisem Ali <maisem@tailscale.com>
2 years ago
Brad Fitzpatrick 8725b14056 all: migrate more code code to net/netip directly
Instead of going through the tailscale.com/net/netaddr transitional
wrappers.

Updates #5162

Change-Id: I3dafd1c2effa1a6caa9b7151ecf6edd1a3fda3dd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 116f55ff66 all: gofmt for Go 1.19
Updates #5210

Change-Id: Ib02cd5e43d0a8db60c1f09755a8ac7b140b670be
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
nyghtowl e6e1976c3a net/dns: remove systemd-resolved ping
Ping only needed to ensure system awak otherwise utilizing resolvConf to set dns mode.

Signed-off-by: nyghtowl <warrick@tailscale.com>
2 years ago
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>
2 years ago
Brad Fitzpatrick 6a396731eb all: use various net/netip parse funcs directly
Mechanical change with perl+goimports.

Changed {Must,}Parse{IP,IPPrefix,IPPort} to their netip variants, then
goimports -d .

Finally, removed the net/netaddr wrappers, to prevent future use.

Updates #5162

Change-Id: I59c0e38b5fbca5a935d701645789cddf3d7863ad
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
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>
2 years ago
Aaron Klotz 1cae618b03 net/dns: add Windows group policy notifications to the NRPT rule manager
As discussed in previous PRs, we can register for notifications when group
policies are updated and act accordingly.

This patch changes nrptRuleDatabase to receive notifications that group policy
has changed and automatically move our NRPT rules between the local and
group policy subkeys as needed.

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
2 years ago
Melanie Warrick f17873e0f4
net/dns: handle D-Bus restarts in resolved manager (#5026)
When dbus restarts it can cause the tailscaled to crash because the nil
signal was not handled in resolved.Fixing so the nil signal leads to a
connection reset and tailscaled stays connected to systemd when dbus restarted.

Fixes #4645

Co-authored-by: James Tucker <james@tailscale.com>
Signed-off-by: nyghtowl <warrick@tailscale.com>

Co-authored-by: James Tucker <james@tailscale.com>
2 years ago
Andrew Dunham c7993d2b88
net/dns/resolver: add fuzz/unit test for #2533 (#5018)
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
2 years ago
Tom DNetto d6817d0f22 net/dns/resolver: respond with SERVFAIL if all upstreams fail
Fixes #4722

Signed-off-by: Tom DNetto <tom@tailscale.com>
2 years ago
Brad Fitzpatrick aa37aece9c ipn/ipnlocal, net/dns*, util/cloudenv: add AWS DNS support
And remove the GCP special-casing from ipn/ipnlocal; do it only in the
forwarder for *.internal.

Fixes #4980
Fixes #4981

Change-Id: I5c481e96d91f3d51d274a80fbd37c38f16dfa5cb
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 88c2afd1e3 ipn/ipnlocal, net/dns*, util/cloudenv: specialize DNS config on Google Cloud
This does three things:

* If you're on GCP, it adds a *.internal DNS split route to the
  metadata server, so we never break GCP DNS names. This lets people
  have some Tailscale nodes on GCP and some not (e.g. laptops at home)
  without having to add a Tailnet-wide *.internal DNS route.
  If you already have such a route, though, it won't overwrite it.

* If the 100.100.100.100 DNS forwarder has nowhere to forward to,
  it forwards it to the GCP metadata IP, which forwards to 8.8.8.8.
  This means there are never errNoUpstreams ("upstream nameservers not set")
  errors on GCP due to e.g. mangled /etc/resolv.conf (GCP default VMs
  don't have systemd-resolved, so it's likely a DNS supremacy fight)

* makes the DNS fallback mechanism use the GCP metadata IP as a
  fallback before our hosted HTTP-based fallbacks

I created a default GCP VM from their web wizard. It has no
systemd-resolved.

I then made its /etc/resolv.conf be empty and deleted its GCP
hostnames in /etc/hosts.

I then logged in to a tailnet with no global DNS settings.

With this, tailscaled writes /etc/resolv.conf (direct mode, as no
systemd-resolved) and sets it to 100.100.100.100, which then has
regular DNS via the metadata IP and *.internal DNS via the metadata IP
as well. If the tailnet configures explicit DNS servers, those are used
instead, except for *.internal.

This also adds a new util/cloudenv package based on version/distro
where the cloud type is only detected once. We'll likely expand it in
the future for other clouds, doing variants of this change for other
popular cloud environments.

Fixes #4911

RELNOTES=Google Cloud DNS improvements

Change-Id: I19f3c2075983669b2b2c0f29a548da8de373c7cf
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
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>
2 years ago
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>
2 years ago
Maisem Ali 80157f3f37 net/dns/resolver: add support for <IPv4>.via-<site-id>
Currently we only support "via-<site-id>.<IPv4>", however that does not
work with Google Chrome which parses `http://via-1.10.0.0.1` as a search
string and not as a URL. This commit introduces "<IPv4>.via-<site-id>"
(`http://10.0.0.1.via-1`) which is parsed correctly by Chrome.

Updates #3616

Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
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>
3 years ago
Tom acfe5bd33b
net/dns{., resolver}: time out DNS queries after 10 seconds (#4690)
Fixes https://github.com/tailscale/corp/issues/5198

The upstream forwarder will block indefinitely on `udpconn.ReadFrom` if no
reply is recieved, due to the lack of deadline on the connection object.

There still isn't a deadline on the connection object, but the automatic closing
of the context on deadline expiry will close the connection via `closeOnCtxDone`,
unblocking the read and resulting in a normal teardown.

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Maisem Ali fd99c54e10 tailcfg,all: change structs to []*dnstype.Resolver
Signed-off-by: Maisem Ali <maisem@tailscale.com>
3 years ago
Tom d1d6ab068e
net/dns, wgengine: implement DNS over TCP (#4598)
* net/dns, wgengine: implement DNS over TCP

Signed-off-by: Tom DNetto <tom@tailscale.com>

* wgengine/netstack: intercept only relevant port/protocols to quad-100

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Tom DNetto 2a0b5c21d2 net/dns/{., resolver}, wgengine: fix goroutine leak on shutdown
Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Tom DNetto 7f45734663 assorted: documentation and readability fixes
This were intended to be pushed to #4408, but in my excitement I
forgot to git push :/ better late than never.

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Tom DNetto 5b85f848dd net/dns,net/dns/resolver: refactor channels/magicDNS out of Resolver
Moves magicDNS-specific handling out of Resolver & into dns.Manager. This
greatly simplifies the Resolver to solely issuing queries and returning
responses, without channels.

Enforcement of max number of in-flight magicDNS queries, assembly of
synthetic UDP datagrams, and integration with wgengine for
recieving/responding to magicDNS traffic is now entirely in Manager.
This path is being kept around, but ultimately aims to be deleted and
replaced with a netstack-based path.

This commit is part of a series to implement magicDNS using netstack.

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Tom DNetto 5fb8e01a8b net/dns/resolver: add metric for number of truncated dns packets
Updates #2067

This should help us determine if more robust control of edns parameters
+ implementing answer truncation is warranted, given its likely complexity.

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Brad Fitzpatrick e97209c6bf net/dns: add tailscaled-on-macOS DNS OSConfigurator
This populates DNS suffixes ("ts.net", etc) in /etc/resolver/* files
to point to 100.100.100.100 so MagicDNS works.

It also sets search domains.

Updates #4276

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Tom DNetto 78fededaa5 net/dns/resolver: support magic resolution of via-<siteid>.<ip4> domains
Updates #3616

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Tom DNetto df26c63793 net/dns/resolver, net/tsaddr: fix reverse lookups in 4to6 IP range
Fixes #4439

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Brad Fitzpatrick cc575fe4d6 net/dns: schedule DoH upgrade explicitly, fix Resolver.Addr confusion
Two changes in one:

* make DoH upgrades an explicitly scheduled send earlier, when we come
  up with the resolvers-and-delay send plan. Previously we were
  getting e.g.  four Google DNS IPs and then spreading them out in
  time (for back when we only did UDP) but then later we added DoH
  upgrading at the UDP packet layer, which resulted in sometimes
  multiple DoH queries to the same provider running (each doing happy
  eyeballs dialing to 4x IPs themselves) for each of the 4 source IPs.
  Instead, take those 4 Google/Cloudflare IPs and schedule 5 things:
  first the DoH query (which can use all 4 IPs), and then each of the
  4 IPs as UDP later.

* clean up the dnstype.Resolver.Addr confusion; half the code was
  using it as an IP string (as documented) as half was using it as
  an IP:port (from some prior type we used), primarily for tests.
  Instead, document it was being primarily an IP string but also
  accepting an IP:port for tests, then add an accessor method on it
  to get the IPPort and use that consistently everywhere.

Change-Id: Ifdd72b9e45433a5b9c029194d50db2b9f9217b53
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick e3a4952527 net/dns/resolver: count errors when racing DNS queries, fail earlier
If all N queries failed, we waited until context timeout (in 5
seconds) to return.

This makes (*forwarder).forward fail fast when the network's
unavailable.

Change-Id: Ibbb3efea7ed34acd3f3b29b5fee00ba8c7492569
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick d9efbd97cb net/dns: remove an unused function
Change-Id: I7c920c76223ffac37954ef2a18754afc52177598
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick ecea6cb994 net/dns/resolver: make DoH dialer use existing dnscache happy eyeball dialer
Simplify the ability to reason about the DoH dialing code by reusing the
dnscache's dialer we already have.

Also, reduce the scope of the "ip" variable we don't want to close over.

This necessarily adds a new field to dnscache.Resolver:
SingleHostStaticResult, for when the caller already knows the IPs to be
returned.

Change-Id: I9f2aef7926f649137a5a3e63eebad6a3fffa48c0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
phirework 52d32c94d8
net/dns/publicdns: add missing call to sync.Once.Do (#4410)
Signed-off-by: Jenny Zhang <jz@tailscale.com>
3 years ago
phirework 83c734a6e0
net/dns, util/publicdns: extract public DNS mapping into own package (#4405)
This extracts DOH mapping of known public DNS providers in
forwarder.go into its own package, to be consumed by other repos

Signed-off-by: Jenny Zhang <jz@tailscale.com>
3 years ago
Tom 24bdcbe5c7
net/dns, net/dns/resolver, wgengine: refactor DNS request path (#4364)
* net/dns, net/dns/resolver, wgengine: refactor DNS request path

Previously, method calls into the DNS manager/resolver types handled DNS
requests rather than DNS packets. This is fine for UDP as one packet
corresponds to one request or response, however will not suit an
implementation that supports DNS over TCP.

To support PRs implementing this in the future, wgengine delegates
all handling/construction of packets to the magic DNS endpoint, to
the DNS types themselves. Handling IP packets at this level enables
future support for both UDP and TCP.

Signed-off-by: Tom DNetto <tom@tailscale.com>
3 years ago
Tom 6be7931eb4
net/dns/resolver: return symbolic PTR records for TS service IPs (#4361)
Fixes #1233

Signed-off-by: Tom DNetto <tom@tailscale.com>

Co-authored-by: Tom DNetto <tom@tailscale.com>
3 years ago
Brad Fitzpatrick f2041c9088 all: use strings.Cut even more
Change-Id: I943ce72c6f339589235bddbe10d07799c4e37979
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Josh Bleecher Snyder 0868329936 all: use any instead of interface{}
My favorite part of generics.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Brad Fitzpatrick 61ee72940c all: use Go 1.18's strings.Cut
More remain.

Change-Id: I6ec562cc1f687600758deae1c9d7dbd0d04004cb
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Josh Bleecher Snyder 0ef74f37a5 net/dns/resolver: remove closure allocation explanation
As of Go 1.18, the register ABI list includes arm64, amd64,
ppc64, and ppc64le. This is a large enough percentage of the
architectures that it's not worth explaining.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Brad Fitzpatrick 7d897229d9 net/dns: ignore permission errors on Synology DSM7 for now
Updates #4017

Change-Id: Ia7fd4df47588c010dea8e63d88f397cc8eb748e5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 2ff481ff10 net/dns: add health check for particular broken-ish Linux DNS config
Updates #3937 (need to write docs before closing)

Change-Id: I1df7244cfbb0303481e2621ee750d21358bd67c6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick c988bd6ed1 net/dns/resolvconffile: unify three /etc/resolv.conf parsers into new package
Change-Id: I2120893ca802d12f1bd0407d49077d3672627d33
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 21358cf2f5 net/dns: slightly optimize dbusPing for non-dbus case [Linux]
Avoid some work when D-Bus isn't running.

Change-Id: I6f89bb75fdb24c13f61be9b400610772756db1ef
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 37e7a387ff net/dns: remove some unused code for detecting systemd-resolved [Linux]
Change-Id: I19c5fd2cdacfb9e5b688ccd9b4336ae4edffc445
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 15599323a1 net/dns: fix systemd-resolved detection race at boot
If systemd-resolved is enabled but not running (or not yet running,
such as early boot) and resolv.conf is old/dangling, we weren't
detecting systemd-resolved.

This moves its ping earlier, which will trigger it to start up and
write its file.

Updates #3362 (likely fixes)
Updates #3531 (likely fixes)

Change-Id: I6392944ac59f600571c43b8f7a677df224f2beed
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Denton Gentry dbea8217ac net/dns: add NetworkManager regression test
Use the exact /etc/resolv.conf file from a user report.
Updates https://github.com/tailscale/tailscale/issues/3531

Signed-off-by: Denton Gentry <dgentry@tailscale.com>
3 years ago
Aaron Bieber e5cd765e00 net/dns/resolvd: properly handle not having "search" entries
This prevents adding an empty "search" line when no search domains are set.

Signed-off-by: Aaron Bieber <aaron@bolddaemon.com>
3 years ago
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>
3 years ago
Brad Fitzpatrick 6feb8f4c51 net/dns: log why resolved does not look like it's on use [Linux]
Updates #3742
Updates #3531

Change-Id: I9fc7fa0f4bcab1cf8001ba92408c660a5b25f105
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Aaron Bieber 411c6c316c net/dns/resolvd: store nameservers
Currently only search domains are stored. This was an oversight
(under?) on my part.

As things are now, when MagicDNS is on and "Override local DNS" is
off, the dns forwarder has to timeout before names resolve. This
introduces a pretty annoying lang that makes everything feel
extremely slow. You will also see an error: "upstream nameservers
not set".

I tested with "Override local DNS" on and off. In both situations
things seem to function as expected (and quickly).

Signed-off-by: Aaron Bieber <aaron@bolddaemon.com>
3 years ago