Commit Graph

55 Commits (c2a7f17f2b378897f4545ad6f43891f150423487)

Author SHA1 Message Date
Nick Hill c2144c44a3 net/dns/resolver: update (*forwarder).forwardWithDestChan to always return an error unless it sends a response to responseChan
We currently have two executions paths where (*forwarder).forwardWithDestChan
returns nil, rather than an error, without sending a DNS response to responseChan.

These paths are accompanied by a comment that reads:
// Returning an error will cause an internal retry, there is
// nothing we can do if parsing failed. Just drop the packet.
But it is not (or no longer longer) accurate: returning an error from forwardWithDestChan
does not currently cause a retry.

Moreover, although these paths are currently unreachable due to implementation details,
if (*forwarder).forwardWithDestChan were to return nil without sending a response to
responseChan, it would cause a deadlock at one call site and a panic at another.

Therefore, we update (*forwarder).forwardWithDestChan to return errors in those two paths
and remove comments that were no longer accurate and misleading.

Updates #cleanup
Updates #13571

Signed-off-by: Nick Hill <mykola.khyl@gmail.com>
2 months ago
Jonathan Nobels 19b0c8a024
net/dns, health: raise health warning for failing forwarded DNS queries (#12888)
updates tailscale/corp#21823

Misconfigured, broken, or blocked DNS will often present as
"internet is broken'" to the end user.  This  plumbs the health tracker
into the dns manager and forwarder and adds a health warning
with a 5 second delay that is raised on failures in the forwarder and
lowered on successes.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>
4 months ago
Nick Khyl 4cdc4ed7db net/dns/resolver: return an empty successful response instead of NXDomain when resolving A records for 4via6 domains
As quad-100 is an authoritative server for 4via6 domains, it should always return responses
with a response code of 0 (indicating no error) when resolving records for these domains.
If there's no resource record of the specified type (e.g. A), it should return a response
with an empty answer section rather than NXDomain. Such a response indicates that there
is at least one RR of a different type (e.g., AAAA), suggesting the Windows stub resolver
to look for it.

Fixes tailscale/corp#20767

Signed-off-by: Nick Khyl <nickk@tailscale.com>
6 months ago
Andrea Gottardo dd77111462
xcode/iOS: set MatchDomains when no route requires a custom DNS resolver (#10576)
Updates https://github.com/tailscale/corp/issues/15802.

On iOS exclusively, this PR adds logic to use a split DNS configuration in more cases, with the goal of improving battery life. Acting as the global DNS resolver on iOS should be avoided, as it leads to frequent wakes of IPNExtension.

We try to determine if we can have Tailscale only handle DNS queries for resources inside the tailnet, that is, all routes in the DNS configuration do not require a custom resolver (this is the case for app connectors, for instance).

If so, we set all Routes as MatchDomains. This enables a split DNS configuration which will help preserve battery life. Effectively, for the average Tailscale user who only relies on MagicDNS to resolve *.ts.net domains, this means that Tailscale DNS will only be used for those domains.

This PR doesn't affect users with Override Local DNS enabled. For these users, there should be no difference and Tailscale will continue acting as a global DNS resolver.

Signed-off-by: Andrea Gottardo <andrea@tailscale.com>
6 months ago
Brad Fitzpatrick 3672f29a4e net/netns, net/dns/resolver, etc: make netmon required in most places
The goal is to move more network state accessors to netmon.Monitor
where they can be cheaper/cached. But first (this change and others)
we need to make sure the one netmon.Monitor is plumbed everywhere.

Some notable bits:

* tsdial.NewDialer is added, taking a now-required netmon

* because a tsdial.Dialer always has a netmon, anything taking both
  a Dialer and a NetMon is now redundant; take only the Dialer and
  get the NetMon from that if/when needed.

* netmon.NewStatic is added, primarily for tests

Updates tailscale/corp#10910
Updates tailscale/corp#18960
Updates #7967
Updates #3299

Change-Id: I877f9cb87618c4eb037cee098241d18da9c01691
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 7c1d6e35a5 all: use Go 1.22 range-over-int
Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Andrew Lytvynov 2716250ee8
all: cleanup unused code, part 2 (#10670)
And enable U1000 check in staticcheck.

Updates #cleanup

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
11 months ago
Andrew Dunham 286c6ce27c
net/dns/resolver: race UDP and TCP queries (#9544)
Instead of just falling back to making a TCP query to an upstream DNS
server when the UDP query returns a truncated query, also start a TCP
query in parallel with the UDP query after a given race timeout. This
ensures that if the upstream DNS server does not reply over UDP (or if
the response packet is blocked, or there's an error), we can still make
queries if the server replies to TCP queries.

This also adds a new package, util/race, to contain the logic required for
racing two different functions and returning the first non-error answer.

Updates tailscale/corp#14809

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I4311702016c1093b1beaa31b135da1def6d86316
1 year ago
Andrew Dunham 530aaa52f1 net/dns: retry forwarder requests over TCP
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
1 year ago
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>
2 years ago
Mihai Parparita 4722f7e322 all: move network monitoring from wgengine/monitor to net/netmon
We're using it in more and more places, and it's not really specific to
our use of Wireguard (and does more just link/interface monitoring).

Also removes the separate interface we had for it in sockstats -- it's
a small enough package (we already pull in all of its dependencies
via other paths) that it's not worth the extra complexity.

Updates #7621
Updates #7850

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2 years ago
Andrew Dunham f85dc6f97c
ci: add more lints (#7909)
This is a follow-up to #7905 that adds two more linters and fixes the corresponding findings. As per the previous PR, this only flags things that are "obviously" wrong, and fixes the issues found.

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I8739bdb7bc4f75666a7385a7a26d56ec13741b7c
2 years ago
Maisem Ali 1a30b2d73f all: use tstest.Replace more
Signed-off-by: Maisem Ali <maisem@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
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 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 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
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
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
Maisem Ali fd99c54e10 tailcfg,all: change structs to []*dnstype.Resolver
Signed-off-by: Maisem Ali <maisem@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 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
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
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
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 486059589b all: gofmt -w -s (simplify) tests
And it updates the build tag style on a couple files.

Change-Id: I84478d822c8de3f84b56fa1176c99d2ea5083237
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick cced414c7d net/dns/resolver: add Windows ExitDNS service support, using net package
Updates #1713
Updates #835

Change-Id: Ia71e96d0632c2d617b401695ad68301b07c1c2ec
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick c37af58ea4 net/tsdial: move more weirdo dialing into new tsdial package, plumb
Not done yet, but this move more of the outbound dial special casing
from random packages into tsdial, which aspires to be the one unified
place for all outbound dialing shenanigans.

Then this plumbs it all around, so everybody is ultimately
holding on to the same dialer.

As of this commit, macOS/iOS using an exit node should be able to
reach to the exit node's DoH DNS proxy over peerapi, doing the sockopt
to stay within the Network Extension.

A number of steps remain, including but limited to:

* move a bunch more random dialing stuff

* make netstack-mode tailscaled be able to use exit node's DNS proxy,
  teaching tsdial's resolver to use it when an exit node is in use.

Updates #1713

Change-Id: I1e8ee378f125421c2b816f47bc2c6d913ddcd2f5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Josh Bleecher Snyder 94fb42d4b2 all: use testingutil.MinAllocsPerRun
There are a few remaining uses of testing.AllocsPerRun:
Two in which we only log the number of allocations,
and one in which dynamically calculate the allocations
target based on a different AllocsPerRun run.

This also allows us to tighten the "no allocs"
test in wgengine/filter.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Brad Fitzpatrick 676fb458c3 net/dns/resolver: make hasRDNSBonjourPrefix match shorter queries too
Fixes tailscale/corp#2886
Updates tailscale/corp#2820
Updates #2442

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
David Crawshaw 9502b515f1 net/dns: replace resolver IPs with type for DoH
We currently plumb full URLs for DNS resolvers from the control server
down to the client. But when we pass the values into the net/dns
package, we throw away any URL that isn't a bare IP. This commit
continues the plumbing, and gets the URL all the way to the built in
forwarder. (It stops before plumbing URLs into the OS configurations
that can handle them.)

For #2596

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
3 years ago
David Anderson 39748e9562 net/dns/resolver: authoritatively return NXDOMAIN for reverse zones we own.
Fixes #2774

Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Emmanuel T Odeke 0daa32943e all: add (*testing.B).ReportAllocs() to every benchmark
This ensures that we can properly track and catch allocation
slippages that could otherwise have been missed.

Fixes #2748
3 years ago
Adrian Dewhurst 8bdf878832 net/dns/resolver: use forwarded dns txid directly
Previously, we hashed the question and combined it with the original
txid which was useful when concurrent queries were multiplexed on a
single local source port. We encountered some situations where the DNS
server canonicalizes the question in the response (uppercase converted
to lowercase in this case), which resulted in responses that we couldn't
match to the original request due to hash mismatches. This includes a
new test to cover that situation.

Fixes #2597

Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
3 years ago
Josh Bleecher Snyder 881bb8bcdc net/dns/resolver: allow an extra alloc for go closure allocation
Go 1.17 switches to a register ABI on amd64 platforms.
Part of that switch is that go and defer calls use an argument-less
closure, which allocates. This means that we have an extra
alloc in some DNS work. That's unfortunate but not a showstopper,
and I don't see a clear path to fixing it.
The other performance benefits from the register ABI will all
but certainly outweigh this extra alloc.

Fixes #2545

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Adrian Dewhurst bcaae3e074 net/dns/resolver: clamp EDNS size
This change (subject to some limitations) looks for the EDNS OPT record
in queries and responses, clamping the size field to fit within our DNS
receive buffer. If the size field is smaller than the DNS receive buffer
then it is left unchanged.

I think we will eventually need to transition to fully processing the
DNS queries to handle all situations, but this should cover the most
common case.

Mostly fixes #2066

Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
3 years ago
Brad Fitzpatrick 45e64f2e1a net/dns{,/resolver}: refactor DNS forwarder, send out of right link on macOS/iOS
Fixes #2224
Fixes tailscale/corp#2045

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick 733d52827b net/dns/resolver: skip test on macOS
Fixes #2229

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Adrian Dewhurst 8b11937eaf net/dns/resolver: permit larger max responses, signal truncation
This raises the maximum DNS response message size from 512 to 4095. This
should be large enough for almost all situations that do not need TCP.
We still do not recognize EDNS, so we will still forward requests that
claim support for a larger response size than 4095 (that will be solved
later). For now, when a response comes back that is too large to fit in
our receive buffer, we now set the truncation flag in the DNS header,
which is an improvement from before but will prompt attempts to use TCP
which isn't supported yet.

On Windows, WSARecvFrom into a buffer that's too small returns an error
in addition to the data. On other OSes, the extra data is silently
discarded. In this case, we prefer the latter so need to catch the error
on Windows.

Partially addresses #1123

Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
4 years ago
Josh Bleecher Snyder 25df067dd0 all: adapt to opaque netaddr types
This commit is a mishmash of automated edits using gofmt:

gofmt -r 'netaddr.IPPort{IP: a, Port: b} -> netaddr.IPPortFrom(a, b)' -w .
gofmt -r 'netaddr.IPPrefix{IP: a, Port: b} -> netaddr.IPPrefixFrom(a, b)' -w .

gofmt -r 'a.IP.Is4 -> a.IP().Is4' -w .
gofmt -r 'a.IP.As16 -> a.IP().As16' -w .
gofmt -r 'a.IP.Is6 -> a.IP().Is6' -w .
gofmt -r 'a.IP.As4 -> a.IP().As4' -w .
gofmt -r 'a.IP.String -> a.IP().String' -w .

And regexps:

\w*(.*)\.Port = (.*)  ->  $1 = $1.WithPort($2)
\w*(.*)\.IP = (.*)  ->  $1 = $1.WithIP($2)

And lots of manual fixups.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
4 years ago
David Anderson 1a371b93be util/dnsname: add FQDN type, use throughout codebase.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 1bf91c8123 net/dns/resolver: remove unused err return value.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 9f105d3968 net/dns/resolver: teach the forwarder to do per-domain routing.
Given a DNS route map, the forwarder selects the right set of
upstreams for a given name.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 90f82b6946 net/dns/resolver: add live reconfig, plumb through to ipnlocal.
The resolver still only supports a single upstream config, and
ipn/wgengine still have to split up the DNS config, but this moves
closer to unifying the DNS configs.

As a handy side-effect of the refactor, IPv6 MagicDNS records exist
now.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson dbe4f6f42d net/dns/resolver: unexport Resolve and ResolveReverse.
They're only used internally and in tests, and have surprising
semantics in that they only resolve MagicDNS names, not upstream
resolver queries.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago