Control sends ExitNodeDNSResolvers when configured for IsWireGuardOnly
nodes that are to be used as the default resolver with a lower
precedence than split DNS, and a lower precedence than "Override local
DNS", but otherwise before local DNS is used when the exit node is in
use.
Neither of the below changes were problematic, but appeared so alongside
a number of other client and external changes. See tailscale/corp#14809.
Reland ea9dd8fabc.
Reland d52ab181c3.
Updates #9377
Updates tailscale/corp#14809
Signed-off-by: James Tucker <james@tailscale.com>
We weren't correctly retrying truncated requests to an upstream DNS
server with TCP. Instead, we'd return a truncated request to the user,
even if the user was querying us over TCP and thus able to handle a
large response.
Also, add an envknob and controlknob to allow users/us to disable this
behaviour if it turns out to be buggy (✨ DNS ✨).
Updates #9264
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ifb04b563839a9614c0ba03e9c564e8924c1a2bfd
This PR plumbs through awareness of an IPv6 SNAT/masquerade address from the wire protocol
through to the low-level (tstun / wgengine). This PR is the first in two PRs for implementing
IPv6 NAT support to/from peers.
A subsequent PR will implement the data-plane changes to implement IPv6 NAT - this is just plumbing.
Signed-off-by: Tom DNetto <tom@tailscale.com>
Updates ENG-991
Like PeerCapMap, add a field to `tailcfg.Node` which provides
a map of Capability to raw JSON messages which are deferred to be
parsed later by the application code which cares about the specific
capabilities. This effectively allows us to prototype new behavior
without having to commit to a schema in tailcfg, and it also opens up
the possibilities to develop custom behavior in tsnet applications w/o
having to plumb through application specific data in the MapResponse.
Updates #4217
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This adds a new RawMessage type backed by string instead of the
json.RawMessage which is backed by []byte. The byte slice makes
the generated views be a lot more defensive than the need to be
which we can get around by using a string instead.
Updates #cleanup
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Tailscale exit nodes provide DNS service over the peer API, however
IsWireGuardOnly nodes do not have a peer API, and instead need client
DNS parameters passed in their node description.
For Mullvad nodes this will contain the in network 10.64.0.1 address.
Updates #9377
Signed-off-by: James Tucker <james@tailscale.com>
tailcfg.Node zero-value clone equality checks failed when I added a
[]*foo to the structure, as the zero value and it's clone contained a
different slice header.
Updates #9377
Updates #9408
Signed-off-by: James Tucker <james@tailscale.com>
Currently only the top four most popular changes: endpoints, DERP
home, online, and LastSeen.
Updates #1909
Change-Id: I03152da176b2b95232b56acabfb55dcdfaa16b79
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
It's been implicitly enabled (based on capver) for years.
Updates #cleanup
Change-Id: I8ff1ab844f9ed75c97e866e778dfc0b56cfa98a2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Cache the last `ClientVersion` value that was received from coordination
server and pass it in the localapi `/status` response.
When running `tailscale status`, print a message if `RunningAsLatest` is
`false`.
Updates #6907
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
Log some progress info to make updates more debuggable. Also, track
whether an active update is already started and return an error if
a concurrent update is attempted.
Some planned future PRs:
* add JSON output to `tailscale update`
* use JSON output from `tailscale update` to provide a more detailed
status of in-progress update (stage, download progress, etc)
Updates #6907
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
This eventually allows encoding packages that may respect
the proposed encoding.TextAppender interface.
The performance gains from this is between 10-30%.
Updates tailscale/corp#14379
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
Actually fixed in 77ff705545 but that was cherry-picked to a branch
and we don't bump capver in branches.
This tells the control plane that UPnP should be re-enabled going
forward.
Updates #8992
Change-Id: I5c4743eb52fdee94175668c368c0f712536dc26b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
In b987b2ab18 (2021-01-12) when we introduced sharing we mapped
the sharer to the userid at a low layer, mostly to fix the display of
"tailscale status" and the client UIs, but also some tests.
The commit earlier today, 7dec09d169, removed the 2.5yo option
to let clients disable that automatic mapping, as clearly we were never
getting around to it.
This plumbs the Sharer UserID all the way to ipnstatus so the CLI
itself can choose to print out the Sharer's identity over the node's
original owner.
Then we stop mangling Node.User and let clients decide how they want
to render things.
To ease the migration for the Windows GUI (which currently operates on
tailcfg.Node via the NetMap from WatchIPNBus, instead of PeerStatus),
a new method Node.SharerOrUser is added to do the mapping of
Sharer-else-User.
Updates #1909
Updates tailscale/corp#1183
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
It had a custom Clone func with a TODO to replace with cloner, resolve
that todo. Had to pull out the embedded Auth struct into a named struct.
Updates #cleanup
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Make it just a views.Slice[netip.Prefix] instead of its own named type.
Having the special case led to circular dependencies in another WIP PR
of mine.
Updates #8948
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Now a nodeAttr: ForceBackgroundSTUN, DERPRoute, TrimWGConfig,
DisableSubnetsIfPAC, DisableUPnP.
Kept support for, but also now a NodeAttr: RandomizeClientPort.
Removed: SetForceBackgroundSTUN, SetRandomizeClientPort (both never
used, sadly... never got around to them. But nodeAttrs are better
anyway), EnableSilentDisco (will be a nodeAttr later when that effort
resumes).
Updates #8923
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This PR adds DNSFilterURL to the DNSConfig type to be used by
control changes to add DNS filtering logic
Fixes #cleanup
Signed-off-by: Richard Castro <richard@tailscale.com>
To record wether user is using iptables or nftables after we add support to nftables on linux, we
are adding a field FirewallMode to NetInfo in HostInfo to reflect what firewall mode the host is
running, and form metrics. The information is gained from a global constant in hostinfo.go. We
set it when selection heuristic made the decision, and magicsock reports this to control.
Updates: tailscale/corp#13943
Signed-off-by: KevinLiang10 <kevinliang@tailscale.com>
Instead of having updates replace the map polls, create
a third goroutine which is solely responsible for making
sure that control is aware of the latest client state.
This also makes it so that the streaming map polls are only
broken when there are auth changes, or the client is paused.
Updates tailscale/corp#5761
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Define PeerCapabilty and PeerCapMap as the new way of sending down
inter-peer capability information.
Previously, this was unstructured and you could only send down strings
which got too limiting for certain usecases. Instead add the ability
to send down raw JSON messages that are opaque to Tailscale but provide
the applications to define them however they wish.
Also update accessors to use the new values.
Updates #4217
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This allows providing additional information to the client about how to
select a home DERP region, such as preferring a given DERP region over
all others.
Updates #8603
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I7c4a270f31d8585112fab5408799ffba5b75266f
We were storing a lot of "ExitNodeFilteredSet":null in the database.
Updates tailscale/corp#1818 (found in the process)
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
The server hasn't sent it in ages.
Updates #cleanup
Change-Id: I9695ab0f074ec6fb006e11faf3cdfc5ca049fbf8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This change updates the documentation for the fields on the location
struct.
Updates tailscale/corp#12146
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This change adds Location field to HostInfo.
Location contains the option for a Country, CountryCode, City, CityCode
and a Priority. Neither of these fields are populated by default.
The Priority field is used to determine the priority an exit
node should be given for use, if the field is set. The higher the value
set, the higher priority the node should be given for use.
Updates tailscale/corp#12146
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This basically allows running services on the SSH client and reaching
them from the SSH server during the session.
Updates #6575
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This change introduces a SSHSessionRecordingFailed event type
that is used when a session recording fails to start or fails during a
session, and the on failure indicates that it should fail open.
Updates tailscale/corp#9967
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This change bumps the capability version to 62, after support for
sending SSHEventNotificationRequests to control via noise for failure
events was introduced.
Updates tailscale/corp#9967
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This change adds a ConnectionID field to both SSHEventNotifyRequest and
CastHeader that identifies the ID of a connection to the SSH server.
Updates tailscale/corp#9967
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This change renames SSHFailureNotifyRequest to SSHEventNotifyRequest
to better reflect the additional events we could add in the future.
This change also adds an EventType used to catagories the events.
Updates tailscale/corp#9967
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This adds support to try dialing out to multiple recorders each
with a 5s timeout and an overall 30s timeout. It also starts respecting
the actions `OnRecordingFailure` field if set, if it is not set
it fails open.
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This allows control to specify how to handle situations where the recorder
isn't available.
Updates tailscale/corp#9967
Signed-off-by: Maisem Ali <maisem@tailscale.com>
A follow-up PR will start using this field after we set it in our
production DERPMap.
Updates #7925
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Idb41b79e6055dddb8944f79d91ad4a186ace98c7
This makes `omitempty` actually work, and saves bytes in each map response.
Updates tailscale/corp#8020
Signed-off-by: Maisem Ali <maisem@tailscale.com>
A peer can have IsWireGuardOnly, which means it will not support DERP or
Disco, and it must have Endpoints filled in order to be usable.
In the present implementation only the first Endpoint will be used as
the bestAddr.
Updates tailscale/corp#10351
Co-authored-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
Co-authored-by: James Tucker <james@tailscale.com>
Signed-off-by: James Tucker <james@tailscale.com>
This only adds the field, to be used in a future commit.
Updates tailscale/corp#8020
Co-authored-by: Melanie Warrick <warrick@tailscale.com>
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This change introduces the Recorders field to the SSHRule struct. The
field is used to store and define addresses where the ssh recorder is
located.
Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This allows us to differentiate between the various tsnet apps that
we have like `golinks` and `k8s-operator`.
Signed-off-by: Maisem Ali <maisem@tailscale.com>
These RPCs will be used to power the future 'tailscale lock remove' default behavior
of resigning signatures for which trust is about to be removed.
Signed-off-by: Tom DNetto <tom@tailscale.com>
With #6566 we started to more aggressively bind to the default interface
on Darwin. We are seeing some reports of the wrong cellular interface
being chosen on iOS. To help with the investigation, this adds to knobs
to control the behavior changes:
- CapabilityDebugDisableAlternateDefaultRouteInterface disables the
alternate function that we use to get the default interface on macOS
and iOS (implemented in tailscale/corp#8201). We still log what it
would have returned so we can see if it gets things wrong.
- CapabilityDebugDisableBindConnToInterface is a bigger hammer that
disables binding of connections to the default interface altogether.
Updates #7184
Updates #7188
Signed-off-by: Mihai Parparita <mihai@tailscale.com>
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>
When turned on via environment variable (off by default), this will use
the BSD routing APIs to query what interface index a socket should be
bound to, rather than binding to the default interface in all cases.
Updates #5719
Updates #5940
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ib4c919471f377b7a08cd3413f8e8caacb29fee0b
This allows users to temporarily enable/disable dnscache logging via a
new node capability, to aid in debugging strange connectivity issues.
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I46cf2596a8ae4c1913880a78d0033f8b668edc08
For detecting a non-ideal binary running on the current CPU.
And for helping detect the best Synology package to update to.
Updates #6995
Change-Id: I722f806675b60ce95364471b11c388150c0d4aea
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Add `tailscale version --json` JSON output mode. This will be used
later for a double-opt-in (per node consent like Tailscale SSH +
control config) to let admins do remote upgrades via `tailscale
update` via a c2n call, which would then need to verify the
cmd/tailscale found on disk for running tailscale update corresponds
to the running tailscaled, refusing if anything looks amiss.
Plus JSON output modes are just nice to have, rather than parsing
unstable/fragile/obscure text formats.
Updates #6995
Updates #6907
Change-Id: I7821ab7fbea4612f4b9b7bdc1be1ad1095aca71b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Nodes that are expired, taking into account the time delta calculated
from MapResponse.ControlTime have the newly-added Expired boolean set.
For additional defense-in-depth, also replicate what control does and
clear the Endpoints and DERP fields, and additionally set the node key
to a bogus value.
Updates #6932
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ia2bd6b56064416feee28aef5699ca7090940662a
Previously, `TAILSCALE_USE_WIP_CODE` was needed to hit a bunch of the TKA paths. With
this change:
- Enablement codepaths (NetworkLockInit) and initialization codepaths (tkaBootstrapFromGenesisLocked via tkaSyncIfNeeded)
require either the WIP envknob or CapabilityTailnetLockAlpha.
- Normal operation codepaths (tkaSyncIfNeeded, tkaFilterNetmapLocked) require TKA to be initialized, or either-or the
envknob / capability.
- Auxillary commands (ie: changing tka keys) require TKA to be initialized.
The end result is that it shouldn't be possible to initialize TKA (or subsequently use any of its features) without being
sent the capability or setting the envknob on tailscaled yourself.
I've also pulled out a bunch of unnecessary checks for CanSupportNetworkLock().
Signed-off-by: Tom DNetto <tom@tailscale.com>
There are three specific requirements for Funnel to work:
1) They must accept an invite.
2) They must enable HTTPS.
3) The "funnel" node attribute must be appropriately set up in the ACLs.
Signed-off-by: Shayne Sweeney <shayne@tailscale.com>
* Plumb disablement values through some of the internals of TKA enablement.
* Transmit the node's TKA hash at the end of sync so the control plane understands each node's head.
* Implement /machine/tka/disable RPC to actuate disablement on the control plane.
There is a partner PR for the control server I'll send shortly.
Signed-off-by: Tom DNetto <tom@tailscale.com>
It does nothing and never did and I don't think anybody remembers what
the original goal for it was.
Updates #5229 (fixes, but need to clean it up in another repo too)
Change-Id: I81cc6ff44d6d2888bc43e9145437f4c407907ea6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
We had previously added this to the netcheck report in #5087 but never
copied it into the NetInfo struct. Additionally, add it to log lines so
it's visible to support.
Change-Id: Ib6266f7c6aeb2eb2a28922aeafd950fe1bf5627e
Signed-off-by: Andrew Dunham <andrew@tailscale.com>
And add a CLI/localapi and c2n mechanism to enable it for a fixed
amount of time.
Updates #1548
Change-Id: I71674aaf959a9c6761ff33bbf4a417ffd42195a7
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
* and move goroutine scrubbing code to its own package for reuse
* bump capver to 45
Change-Id: I9b4dfa5af44d2ecada6cc044cd1b5674ee427575
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
At some point we started restarting map polls on health change, but we
don't remember why. Maybe it was a desperate workaround for something.
I'm not sure it ever worked.
Rather than have a haunted graveyard, remove it.
In its place, though, and somewhat as a safety backup, send those
updates over the HTTP/2 noise channel if we have one open. Then if
there was a reason that a map poll restart would help we could do it
server-side. But mostly we can gather error stats and show
machine-level health info for debugging.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
* tailcfg, control/controlhttp, control/controlclient: add ControlDialPlan field
This field allows the control server to provide explicit information
about how to connect to it; useful if the client's link status can
change after the initial connection, or if the DNS settings pushed by
the control server break future connections.
Change-Id: I720afe6289ec27d40a41b3dcb310ec45bd7e5f3e
Signed-off-by: Andrew Dunham <andrew@tailscale.com>
We're adding two log IDs to facilitate data-plane audit logging: a node-specific
log ID, and a domain-specific log ID.
Updated util/deephash/deephash_test.go with revised expectations for tailcfg.Node.
Updates https://github.com/tailscale/corp/issues/6991
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
It was checking if the sshServer was initialized as a proxy, but that
could either not have been initialized yet or Tailscale SSH could have
been disabled after intialized.
Also bump tailcfg.CurrentCapabilityVersion
Signed-off-by: Maisem Ali <maisem@tailscale.com>
For control to fetch a list of Tailscale SSH username candidates to
filter against the Tailnet's SSH policy to present some valid
candidates to a user.
Updates #3802
Updates tailscale/corp#7007
Change-Id: I3dce57b7a35e66891d5e5572e13ae6ef3c898498
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Baby steps towards turning off heartbeat pings entirely as per #540.
This doesn't change any current magicsock functionality and requires additional
changes to send/disco paths before the flag can be turned on.
Updates #540
Change-Id: Idc9a72748e74145b068d67e6dd4a4ffe3932efd0
Signed-off-by: Jenny Zhang <jz@tailscale.com>
Signed-off-by: Jenny Zhang <jz@tailscale.com>
As noted in #5617, our documented method of blocking log.tailscale.io
DNS no longer works due to bootstrap DNS.
Instead, provide an explicit flag (--no-logs-no-support) and/or env
variable (TS_NO_LOGS_NO_SUPPORT=true) to explicitly disable logcatcher
uploads. It also sets a bit on Hostinfo to say that the node is in that
mode so we can end any support tickets from such nodes more quickly.
This does not yet provide an easy mechanism for users on some
platforms (such as Windows, macOS, Synology) to set flags/env. On
Linux you'd used /etc/default/tailscaled typically. Making it easier
to set flags for other platforms is tracked in #5114.
Fixes#5617Fixestailscale/corp#1475
Change-Id: I72404e1789f9e56ec47f9b7021b44c025f7a373a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
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>
Fix broken build from 255c0472fb
"Oh, that's safe to commit because most tests are passing and it's
just a comment change!", I thought, forgetting I'd added a test that
parses its comments.
Change-Id: Iae93d595e06fec48831215a98adbb270f3bfda05
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
gofmt in 1.19 is now opinionated about structured text formatting in
comments. It did not like our style and kept fighting us whenever we
changed these lines. Give up the fight and be a bulleted list for it.
See:
* https://go.dev/doc/go1.19#go-doc and
* https://go.dev/doc/comment
Updates #4872
Change-Id: Ifae431218471217168c003ab3b4e03c394ca8105
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
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>
This lets the control plane can make HTTP requests to nodes.
Then we can use this for future things rather than slapping more stuff
into MapResponse, etc.
Change-Id: Ic802078c50d33653ae1f79d1e5257e7ade4408fd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
So next time something like #5340 happens we can identify all affected
nodes and have the control plane send them health warnings.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Needed to identify the node. A serverside-check the machine key (used
to authenticate the noise session) is that of the specified NodeID
ensures the authenticity of the request.
Signed-off-by: Tom DNetto <tom@tailscale.com>
We're going to want to enable audit logging on a per-Tailnet basis. When this
happens, we want control to inform the Tailnet's clients of this capability.
Signed-off-by: Aaron Klotz <aaron@tailscale.com>
I documented capver 37 in 4ee64681a but forgot to bump the actual
constant. I've done this previously too, so add a test to prevent
it from happening again.
Change-Id: I6f7659db1243d30672121a384beb386d9f9f5b98
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
- A network-lock key is generated if it doesn't already exist, and stored in the StateStore. The public component is communicated to control during registration.
- If TKA state exists on the filesystem, a tailnet key authority is initialized (but nothing is done with it for now).
Signed-off-by: Tom DNetto <tom@tailscale.com>
This adds the inverse to CapabilityFileSharingSend so that senders can
identify who they can Taildrop to.
Updates #2101
Signed-off-by: Maisem Ali <maisem@tailscale.com>
This adds a lighter mechanism for endpoint updates from control.
Change-Id: If169c26becb76d683e9877dc48cfb35f90cc5f24
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
The control plane server doesn't send these to modern clients so we
don't need them in the tree. The server has its own serialization code
to generate legacy MapResponses when needed.
Change-Id: Idd1e5d96ddf9d4306f2da550d20b77f0c252817a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This lets us distinguish "no IPv6 because the device's ISP doesn't
offer IPv6" from "IPv6 is unavailable/disabled in the OS".
Signed-off-by: David Anderson <danderson@tailscale.com>
