Pull request: 2280 dns timeout

Updates #2280.

Squashed commit of the following:

commit d8c6aacb664361a13dde8522de2470dd137bed00
Merge: 84df492b 12f1e4ed
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Jun 15 17:21:41 2021 +0300

    Merge branch 'master' into 2280-dns-timeout

commit 84df492b0134e88e031f586333437f503b90b7ae
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Jun 15 16:49:41 2021 +0300

    home: fix docs & naming

commit af44a86a60ea815ca7100edc34db8acbdcc2cccf
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Jun 15 15:55:12 2021 +0300

    all: imp docs & tests

commit 6ed6599fa0024cc7d14dc7c75ddda62e5179fe00
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Jun 15 15:26:22 2021 +0300

    home: imp duration tests

commit 8fe7cb099dccfce3f9329d7207ef48f488f07e83
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Tue Jun 15 15:04:16 2021 +0300

    all: imp code, docs & tests

commit a989e8a5a6acede0063141cdbfc103b150b33d97
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Sat Jun 12 19:02:23 2021 +0300

    WIP

commit b0362e22040a1d38f81dcc775c5ef6f7d1e94eee
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Sat Jun 12 18:58:09 2021 +0300

    all: imp docs & tests

commit 64b00fd0854f3ddcb0189f3c93f3ffa2a31a98be
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Sat Jun 12 03:44:29 2021 +0300

    home: introduce marshalable duration

commit bfb1a5706c37fcd27bccce4a5aec37dca3cf238b
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Sat Jun 12 01:56:10 2021 +0300

    all: add upstream timeout setting

internal/dnsforward/config.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"sort"
 	"strings"
+	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
 	"github.com/AdguardTeam/AdGuardHome/internal/aghstrings"
@@ -142,6 +143,9 @@ type ServerConfig struct {
 	DNSCryptConfig
 	TLSAllowUnencryptedDOH bool
 
+	// UpstreamTimeout is the timeout for querying upstream servers.
+	UpstreamTimeout time.Duration
+
 	TLSv12Roots *x509.CertPool // list of root CAs for TLSv1.2
 	TLSCiphers  []uint16       // list of TLS ciphers to use
 
@@ -261,6 +265,10 @@ func (s *Server) initDefaultSettings() {
 	if len(s.conf.BlockedHosts) == 0 {
 		s.conf.BlockedHosts = defaultBlockedHosts
 	}
+
+	if s.conf.UpstreamTimeout == 0 {
+		s.conf.UpstreamTimeout = DefaultTimeout
+	}
 }
 
 // prepareUpstreamSettings - prepares upstream DNS server settings
@@ -299,7 +307,7 @@ func (s *Server) prepareUpstreamSettings() error {
 		upstreams,
 		upstream.Options{
 			Bootstrap: s.conf.BootstrapDNS,
-			Timeout:   DefaultTimeout,
+			Timeout:   s.conf.UpstreamTimeout,
 		},
 	)
 	if err != nil {
@@ -313,7 +321,7 @@ func (s *Server) prepareUpstreamSettings() error {
 			defaultDNS,
 			upstream.Options{
 				Bootstrap: s.conf.BootstrapDNS,
-				Timeout:   DefaultTimeout,
+				Timeout:   s.conf.UpstreamTimeout,
 			},
 		)
 		if err != nil {

internal/dnsforward/dnsforward_test.go

@@ -279,6 +279,34 @@ func TestServer(t *testing.T) {
 	}
 }
 
+func TestServer_timeout(t *testing.T) {
+	const timeout time.Duration = time.Second
+
+	t.Run("custom", func(t *testing.T) {
+		srvConf := &ServerConfig{
+			UpstreamTimeout: timeout,
+		}
+
+		s, err := NewServer(DNSCreateParams{})
+		require.NoError(t, err)
+
+		err = s.Prepare(srvConf)
+		require.NoError(t, err)
+
+		assert.Equal(t, timeout, s.conf.UpstreamTimeout)
+	})
+
+	t.Run("default", func(t *testing.T) {
+		s, err := NewServer(DNSCreateParams{})
+		require.NoError(t, err)
+
+		err = s.Prepare(nil)
+		require.NoError(t, err)
+
+		assert.Equal(t, DefaultTimeout, s.conf.UpstreamTimeout)
+	})
+}
+
 func TestServerWithProtectionDisabled(t *testing.T) {
 	s := createTestServer(t, &filtering.Config{}, ServerConfig{
 		UDPListenAddrs: []*net.UDPAddr{{}},

internal/dnsforward/http.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
 	"github.com/AdguardTeam/AdGuardHome/internal/aghstrings"
@@ -529,7 +530,7 @@ func checkPrivateUpstreamExc(u upstream.Upstream) (err error) {
 	return nil
 }
 
-func checkDNS(input string, bootstrap []string, ef excFunc) (err error) {
+func checkDNS(input string, bootstrap []string, timeout time.Duration, ef excFunc) (err error) {
 	if aghstrings.IsCommentOrEmpty(input) {
 		return nil
 	}
@@ -557,7 +558,7 @@ func checkDNS(input string, bootstrap []string, ef excFunc) (err error) {
 	var u upstream.Upstream
 	u, err = upstream.AddressToUpstream(input, upstream.Options{
 		Bootstrap: bootstrap,
-		Timeout:   DefaultTimeout,
+		Timeout:   timeout,
 	})
 	if err != nil {
 		return fmt.Errorf("failed to choose upstream for %q: %w", input, err)
@@ -584,8 +585,9 @@ func (s *Server) handleTestUpstreamDNS(w http.ResponseWriter, r *http.Request) {
 	result := map[string]string{}
 	bootstraps := req.BootstrapDNS
 
+	timeout := s.conf.UpstreamTimeout
 	for _, host := range req.Upstreams {
-		err = checkDNS(host, bootstraps, checkDNSUpstreamExc)
+		err = checkDNS(host, bootstraps, timeout, checkDNSUpstreamExc)
 		if err != nil {
 			log.Info("%v", err)
 			result[host] = err.Error()
@@ -597,7 +599,7 @@ func (s *Server) handleTestUpstreamDNS(w http.ResponseWriter, r *http.Request) {
 	}
 
 	for _, host := range req.PrivateUpstreams {
-		err = checkDNS(host, bootstraps, checkPrivateUpstreamExc)
+		err = checkDNS(host, bootstraps, timeout, checkPrivateUpstreamExc)
 		if err != nil {
 			log.Info("%v", err)
 			// TODO(e.burkov): If passed upstream have already

internal/dnsforward/http_test.go

@@ -18,7 +18,8 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// fakeSystemResolvers is a mock aghnet.SystemResolvers implementation for tests.
+// fakeSystemResolvers is a mock aghnet.SystemResolvers implementation for
+// tests.
 type fakeSystemResolvers struct {
 	// SystemResolvers is embedded here simply to make *fakeSystemResolvers
 	// an aghnet.SystemResolvers without actually implementing all methods.