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net/dns: schedule DoH upgrade explicitly, fix Resolver.Addr confusion

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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>
This commit is contained in:
Brad Fitzpatrick
2022-04-18 21:58:00 -07:00
committed by Brad Fitzpatrick
parent e3a4952527
commit cc575fe4d6
10 changed files with 161 additions and 168 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
ipn/ipnlocal/dnsconfig_test.go
View File

@@ -259,10 +259,10 @@ func TestDNSConfigForNetmap(t *testing.T) {
want: &dns.Config{
Hosts: map[dnsname.FQDN][]netaddr.IP{},
DefaultResolvers: []dnstype.Resolver{
{Addr: "8.8.8.8:53"},
{Addr: "8.8.8.8"},
},
Routes: map[dnsname.FQDN][]dnstype.Resolver{
"foo.com.": {{Addr: "1.2.3.4:53"}},
"foo.com.": {{Addr: "1.2.3.4"}},
},
},
},
@@ -283,7 +283,7 @@ func TestDNSConfigForNetmap(t *testing.T) {
Hosts: map[dnsname.FQDN][]netaddr.IP{},
Routes: map[dnsname.FQDN][]dnstype.Resolver{},
DefaultResolvers: []dnstype.Resolver{
{Addr: "8.8.4.4:53"},
{Addr: "8.8.4.4"},
},
},
},

14
ipn/ipnlocal/local.go
View File

@@ -2207,7 +2207,7 @@ func dnsConfigForNetmap(nm *netmap.NetworkMap, prefs *ipn.Prefs, logf logger.Log
addDefault := func(resolvers []dnstype.Resolver) {
for _, r := range resolvers {
dcfg.DefaultResolvers = append(dcfg.DefaultResolvers, normalizeResolver(r))
dcfg.DefaultResolvers = append(dcfg.DefaultResolvers, r)
}
}
@@ -2236,7 +2236,7 @@ func dnsConfigForNetmap(nm *netmap.NetworkMap, prefs *ipn.Prefs, logf logger.Log
dcfg.Routes[fqdn] = make([]dnstype.Resolver, 0, len(resolvers))
for _, r := range resolvers {
dcfg.Routes[fqdn] = append(dcfg.Routes[fqdn], normalizeResolver(r))
dcfg.Routes[fqdn] = append(dcfg.Routes[fqdn], r)
}
}
@@ -2267,16 +2267,6 @@ func dnsConfigForNetmap(nm *netmap.NetworkMap, prefs *ipn.Prefs, logf logger.Log
return dcfg
}
func normalizeResolver(cfg dnstype.Resolver) dnstype.Resolver {
if ip, err := netaddr.ParseIP(cfg.Addr); err == nil {
// Add 53 here for bare IPs for consistency with previous data type.
return dnstype.Resolver{
Addr: netaddr.IPPortFrom(ip, 53).String(),
}
}
return cfg
}
// SetVarRoot sets the root directory of Tailscale's writable
// storage area . (e.g. "/var/lib/tailscale")
//