Pull request: all: custom autohost tlds

Updates #2393.

Squashed commit of the following:

commit 87034134e240480938cdeec14d6b44294bf6442c
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Mar 25 15:48:46 2021 +0300

    dnsforward: fix

commit abf3a1ce8ed7a148d1cc631007fb0422f6da4ae6
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Mar 25 15:21:11 2021 +0300

    dnsforward: imp code, validation

commit fac389bdafc093ce17a7e0831166b89293b550be
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Mar 25 14:54:45 2021 +0300

    all: add validation, imp docs, tests

commit 21b4532afe59f3b89383cb330c9a7d49ec124b6e
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Mar 24 19:09:43 2021 +0300

    all: custom autohost tlds

internal/home/config.go

@@ -93,6 +93,11 @@ type dnsConfig struct {
 	FilteringEnabled           bool             `yaml:"filtering_enabled"`       // whether or not use filter lists
 	FiltersUpdateIntervalHours uint32           `yaml:"filters_update_interval"` // time period to update filters (in hours)
 	DnsfilterConf              dnsfilter.Config `yaml:",inline"`
+
+	// AutohostTLD is the top-level domain used for known internal hosts.
+	// For example, a machine called "myhost" can be addressed as
+	// "myhost.lan" when AutohostTLD is "lan".
+	AutohostTLD string `yaml:"autohost_tld"`
 }
 
 type tlsConfigSettings struct {
@@ -144,6 +149,7 @@ var config = configuration{
 		},
 		FilteringEnabled:           true, // whether or not use filter lists
 		FiltersUpdateIntervalHours: 24,
+		AutohostTLD:                "lan",
 	},
 	TLS: tlsConfigSettings{
 		PortHTTPS:       443,

internal/home/dns.go

@@ -61,18 +61,27 @@ func initDNSServer() error {
 	Context.dnsFilter = dnsfilter.New(&filterConf, nil)
 
 	p := dnsforward.DNSCreateParams{
-		DNSFilter: Context.dnsFilter,
-		Stats:     Context.stats,
-		QueryLog:  Context.queryLog,
+		DNSFilter:   Context.dnsFilter,
+		Stats:       Context.stats,
+		QueryLog:    Context.queryLog,
+		AutohostTLD: config.DNS.AutohostTLD,
 	}
 	if Context.dhcpServer != nil {
 		p.DHCPServer = Context.dhcpServer
 	}
-	Context.dnsServer = dnsforward.NewServer(p)
+
+	Context.dnsServer, err = dnsforward.NewServer(p)
+	if err != nil {
+		closeDNSServer()
+
+		return fmt.Errorf("dnsforward.NewServer: %w", err)
+	}
+
 	Context.clients.dnsServer = Context.dnsServer
 	dnsConfig, err := generateServerConfig()
 	if err != nil {
 		closeDNSServer()
+
 		return fmt.Errorf("generateServerConfig: %w", err)
 	}
 

internal/home/whois_test.go

@@ -6,15 +6,23 @@ import (
 
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
-func prepareTestDNSServer() error {
+func prepareTestDNSServer(t *testing.T) {
+	t.Helper()
+
 	config.DNS.Port = 1234
-	Context.dnsServer = dnsforward.NewServer(dnsforward.DNSCreateParams{})
+
+	var err error
+	Context.dnsServer, err = dnsforward.NewServer(dnsforward.DNSCreateParams{})
+	require.NoError(t, err)
+
 	conf := &dnsforward.ServerConfig{}
 	conf.UpstreamDNS = []string{"8.8.8.8"}
 
-	return Context.dnsServer.Prepare(conf)
+	err = Context.dnsServer.Prepare(conf)
+	require.NoError(t, err)
 }
 
 // TODO(e.burkov): It's kind of complicated to get rid of network access in this
@@ -22,12 +30,15 @@ func prepareTestDNSServer() error {
 // the server, so it becomes hard to simulate handling of request from test even
 // with substituted upstream.  However, it must be done.
 func TestWhois(t *testing.T) {
-	assert.Nil(t, prepareTestDNSServer())
+	prepareTestDNSServer(t)
 
 	w := Whois{timeoutMsec: 5000}
 	resp, err := w.queryAll(context.Background(), "8.8.8.8")
-	assert.Nil(t, err)
+	assert.NoError(t, err)
+
 	m := whoisParse(resp)
+	require.NotEmpty(t, m)
+
 	assert.Equal(t, "Google LLC", m["orgname"])
 	assert.Equal(t, "US", m["country"])
 	assert.Equal(t, "Mountain View", m["city"])