Commit Graph

98 Commits

Author SHA1 Message Date
Dave Anderson
144c68b80b
net/dns: avoid using NetworkManager as much as possible. (#1945)
Addresses #1699 as best as possible.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-06-10 10:46:08 -04:00
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>
2021-06-08 19:29:12 -04:00
David Anderson
7fab244614 net/dns/resolver: don't spam logs on EHOSTUNREACH.
Fixes #1719.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-06-07 10:45:29 -07:00
David Anderson
e2dcf63420 net/dns: replace AuthoritativeSuffixes with nil Route entries.
This leads to a cleaner separation of intent vs. implementation
(Routes is now the only place specifying who handles DNS requests),
and allows for cleaner expression of a configuration that creates
MagicDNS records without serving them to the OS.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-05-18 14:15:17 -07:00
David Anderson
6690f86ef4 net/dns: always offer MagicDNS records at 100.100.100.100.
Fixes #1886.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-05-18 14:15:17 -07:00
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>
2021-05-16 14:52:00 -07:00
David Anderson
cfde997699 net/dns: don't use interfaces.Tailscale to find the tailscale interface index.
interfaces.Tailscale only returns an interface if it has at least one Tailscale
IP assigned to it. In the resolved DNS manager, when we're called upon to tear
down DNS config, the interface no longer has IPs.

Instead, look up the interface index on construction and reuse it throughout
the daemon lifecycle.

Fixes #1892.

Signed-off-by: David Anderson <dave@natulte.net>
2021-05-10 15:24:42 -07:00
David Anderson
3c8e230ee1 Revert "net/dns: set IPv4 auto mode in NM, so it lets us set DNS."
This reverts commit 7d16c8228b.

I have no idea how I ended up here. The bug I was fixing with this change
fails to reproduce on Ubuntu 18.04 now, and this change definitely does
break 20.04, 20.10, and Debian Buster. So, until we can reliably reproduce
the problem this was meant to fix, reverting.

Part of #1875

Signed-off-by: David Anderson <dave@natulte.net>
2021-05-06 22:31:54 -07:00
David Anderson
5bd38b10b4 net/dns: log the correct error when NM Reapply fails.
Found while debugging #1870.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-05-06 16:02:09 -07:00
David Anderson
7d16c8228b net/dns: set IPv4 auto mode in NM, so it lets us set DNS.
Part of #1870.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-05-06 16:02:09 -07:00
David Anderson
77e2375501 net/dns: don't try to configure LLMNR or mdns in NetworkManager.
Fixes #1870.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-05-06 16:02:09 -07:00
Josh Bleecher Snyder
20e04418ff net/dns: add GOOS build tags
Fixes #1786

Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
2021-04-29 21:34:55 -07:00
David Anderson
bf9ef1ca27 net/dns: stop NetworkManager breaking v6 connectivity when setting DNS.
Tentative fix for #1699

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-29 12:25:47 -07:00
David Anderson
44c2b7dc79 net/dns: on windows, skip site-local v6 resolvers.
Further refinement for tailscale/corp#1662.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-27 18:24:54 -07:00
David Anderson
97d2fa2f56 net/dns: work around WSL DNS implementation flaws.
Fixes tailscale/corp#1662

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-26 16:54:50 -07:00
David Anderson
f6b7d08aea net/dns: work around new NetworkManager in other selection paths.
Further bits of #1788

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-23 22:09:00 -07:00
David Anderson
25ce9885a2 net/dns: don't use NM+resolved for NM >=1.26.6.
NetworkManager fixed the bug that forced us to use NetworkManager
if it's programming systemd-resolved, and in the same release also
made NetworkManager ignore DNS settings provided for unmanaged
interfaces... Which breaks what we used to do. So, with versions
1.26.6 and above, we MUST NOT use NetworkManager to indirectly
program systemd-resolved, but thankfully we can talk to resolved
directly and get the right outcome.

Fixes #1788

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-23 21:13:19 -07:00
David Anderson
30f5d706a1 net/dns/resolver: remove unnecessary/racy WaitGroup.
Fixes #1663

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-22 19:17:37 -07:00
David Anderson
89c81c26c5 net/dns: fix resolved match domains when no nameservers are provided.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-20 17:10:39 -07:00
David Anderson
4be26b269f net/dns: correctly capture all traffic in non-split configs.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-20 16:57:46 -07:00
David Anderson
ca283ac899 net/dns: remove config in openresolv when given an empty DNS config.
Part of #1720.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-20 16:19:34 -07:00
David Anderson
53213114ec net/dns: make debian_resolvconf correctly clear DNS configs.
More of #1720.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-20 15:51:14 -07:00
David Anderson
3b1ab78954 net/dns: restore resolv.conf when given an empty config in directManager.
Fixes #1720.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-20 15:14:40 -07:00
David Anderson
158328ba24 net/dns: remove ForceSplitDNSForTesting.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-20 12:50:08 -07:00
David Anderson
bb0710d51d net/dns: add debugging traces to DNS manager selection on linux.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-14 15:52:41 -07:00
David Anderson
4b70c7b717 net/dns: fix inverted test for NetworkManager.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-14 15:52:22 -07:00
David Anderson
4849a4d3c8 net/dns: error out on linux if /etc/resolv.conf can't be read.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-14 15:35:32 -07:00
David Anderson
1f9b73a531 net/dns: fix freebsd DNS manager selection.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-14 15:34:59 -07:00
Brad Fitzpatrick
c2ca2ac8c4 net/dns: fix FreeBSD build
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-04-13 17:38:17 -07:00
David Anderson
84bd50329a net/dns: fix staticheck.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-13 17:28:37 -07:00
David Anderson
d6bb11b5bf net/dns: implement correct manager detection on linux.
Part of #953.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-13 17:19:00 -07:00
David Anderson
9ef932517b net/dns: fix NM's GetBaseConfig when no configs exist.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-13 17:19:00 -07:00
David Anderson
fe3b1ab747 net/dns: refactor dbus connection setup in resolved manager.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-13 17:19:00 -07:00
David Anderson
854d5d36a1 net/dns: return error from NewOSManager, use it to initialize NM.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-12 15:51:37 -07:00
David Anderson
9aa33b43e6 net/dns: support split and unsplit DNS in NetworkManager.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-12 14:34:08 -07:00
David Anderson
87eb8384f5 net/dns: fix up NetworkManager configurator a bit.
Clear LLMNR and mdns flags, update reasoning for our settings,
and set our override priority harder than before when we want
to be primary resolver.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-11 23:19:50 -07:00
David Anderson
3d81e6260b net/dns: set resolved DefaultRoute setting according to split-dns mode.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-11 20:53:28 -07:00
David Anderson
cca230cc23 net/dns: fix staticcheck errors.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-11 20:53:28 -07:00
Brad Fitzpatrick
4b47393e0c net/dns: pacify staticcheck for now
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2021-04-11 20:43:15 -07:00
David Anderson
a7340c2015 net/dns: support split DNS in systemd-resolved.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-11 18:14:23 -07:00
David Anderson
84430cdfa1 net/dns: improve NetworkManager detection, using more DBus.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-11 15:22:06 -07:00
David Anderson
9a48bac8ad net/dns: rename resolvconf.go to debian_resolvconf.go.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 23:31:14 -07:00
David Anderson
9831f1b183 net/dns: also include 'tail' and 'base' files when fixing up resolv.conf.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 23:01:11 -07:00
David Anderson
e43afe9140 net/dns: implement prior config reading for debian resolvconf.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 22:37:13 -07:00
David Anderson
143e5dd087 net/dns: rename script variable.
Debian resolvconf is not legacy, it's alive and well,
just historically before the other implementations.

Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 21:28:27 -07:00
David Anderson
55b39fa945 net/dns: add documentation to openresolv's config fetch.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 20:21:05 -07:00
David Anderson
61b361bac0 net/dns: teach the openresolv manager to read DNS config.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 19:37:11 -07:00
David Anderson
58760f7b82 net/dns: split resolvconfManager into a debian and an openresolv manager.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 18:55:05 -07:00
David Anderson
5480189313 net/dns: implement a DNS override workaround for legacy resolvconf.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 17:58:13 -07:00
David Anderson
1a371b93be util/dnsname: add FQDN type, use throughout codebase.
Signed-off-by: David Anderson <danderson@tailscale.com>
2021-04-10 17:58:13 -07:00