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>
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>
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>
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>
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>
And remove the GCP special-casing from ipn/ipnlocal; do it only in the
forwarder for *.internal.
Fixes#4980Fixes#4981
Change-Id: I5c481e96d91f3d51d274a80fbd37c38f16dfa5cb
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
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>
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>
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>
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>
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>
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>
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>
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>
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>
* 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>
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>
On Synology, the /etc/resolv.conf has tabs in it, which this
resolv.conf parser (we have two, sigh) didn't handle.
Updates #3710
Change-Id: I86f8e09ad1867ee32fa211e85c382a27191418ea
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Fixes#3660
RELNOTE=MagicDNS now works over IPv6 when CGNAT IPv4 is disabled.
Change-Id: I001e983df5feeb65289abe5012dedd177b841b45
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
And delete the unused code in net/dns/resolver/neterr_*.go.
Change-Id: Ibe62c486bacce2733eb9968c96a98cbbdb2758bd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Don't just ignore them. See if this makes them calm down.
Updates #3363
Change-Id: Id1d66308e26660d26719b2538b577522a1e36b63
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
To convince me it's not as alloc-y as it looks.
Change-Id: I503a0cc267268a23d2973dfde9833c420be4e868
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
And it updates the build tag style on a couple files.
Change-Id: I84478d822c8de3f84b56fa1176c99d2ea5083237
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
