Pull request: AG-28771 conf upstream mode

Squashed commit of the following:

commit afb5a0d8a499bccf7761baea40910f39c92b8a20
Merge: 09ac43c85 abf20c6de
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Mon Dec 25 12:55:45 2023 +0200

    Merge remote-tracking branch 'origin/master' into conf-ups-mode

commit 09ac43c859ef8cbd3bb0488d1a945589cd59ca19
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Fri Dec 22 14:36:07 2023 +0200

    openapi: imp docs

commit d0fbd4349e4bddde73c6e92f75854acfc481ac0d
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Fri Dec 22 11:47:10 2023 +0200

    all: changelog

commit 105f9c50738733b0736a768fb9ee09d2e7fbf42e
Merge: 62a2cf12d 4bc5c346a
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Fri Dec 22 11:27:21 2023 +0200

    Merge remote-tracking branch 'origin/master' into conf-ups-mode

    # Conflicts:
    #	openapi/CHANGELOG.md

commit 62a2cf12df694611888e840a5041a9c517cdfddb
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Fri Dec 22 10:52:59 2023 +0200

    openapi: imp docs

commit 87956c49240da44b216489920feff69996e3502b
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Thu Dec 21 12:08:07 2023 +0200

    dnsforward: imp code

commit bf74d67ad112735d557be3d8fac75964cd99e375
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Wed Dec 20 15:46:38 2023 +0200

    dnsforward: imp code

commit 3a98dee88809a25118a14a1f07eeecbfccb14cd9
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Wed Dec 20 15:41:06 2023 +0200

    dnsforward: imp code

commit 1499da1fa0319ac3ad914171e807446f2c4d2fdb
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Wed Dec 20 13:36:28 2023 +0200

    dnsforward: imp code

commit 228c61a5a0f73cc13655cef8bdaa1995b3f7fced
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Wed Dec 20 13:06:11 2023 +0200

    dnsforward: imp code

commit 069ee22c6d904db4e983135ce87a9fe8d12b7e9a
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Tue Dec 19 12:39:25 2023 +0200

    dnsforward: imp code

commit 90919f99a975862dcb07ac82fb740e4404e48bae
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Tue Dec 19 12:10:43 2023 +0200

    confmigrate: fix

commit a8c329950423b59098d1f2b16d1da7100dd54f8d
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Tue Dec 19 12:08:05 2023 +0200

    dnsforward: imp code

commit 58b53ccd97d353fab0df29f13425b5e341c8fdeb
Author: Dimitry Kolyshev <dkolyshev@adguard.com>
Date:   Mon Dec 18 15:10:01 2023 +0200

    all: conf upstream mode

internal/dnsforward/dnsforward_test.go

@@ -177,6 +177,7 @@ func createTestTLS(t *testing.T, tlsConf TLSConfig) (s *Server, certPem []byte)
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode:     UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{Enabled: false},
 		},
 		ServePlainDNS: true,
@@ -305,6 +306,7 @@ func TestServer(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode:     UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{Enabled: false},
 		},
 		ServePlainDNS: true,
@@ -344,6 +346,7 @@ func TestServer_timeout(t *testing.T) {
 		srvConf := &ServerConfig{
 			UpstreamTimeout: testTimeout,
 			Config: Config{
+				UpstreamMode:     UpstreamModeLoadBalance,
 				EDNSClientSubnet: &EDNSClientSubnet{Enabled: false},
 			},
 			ServePlainDNS: true,
@@ -362,6 +365,7 @@ func TestServer_timeout(t *testing.T) {
 		s, err := NewServer(DNSCreateParams{DNSFilter: createTestDNSFilter(t)})
 		require.NoError(t, err)
 
+		s.conf.Config.UpstreamMode = UpstreamModeLoadBalance
 		s.conf.Config.EDNSClientSubnet = &EDNSClientSubnet{
 			Enabled: false,
 		}
@@ -379,6 +383,7 @@ func TestServer_Prepare_fallbacks(t *testing.T) {
 				"#tls://1.1.1.1",
 				"8.8.8.8",
 			},
+			UpstreamMode:     UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{Enabled: false},
 		},
 		ServePlainDNS: true,
@@ -401,6 +406,7 @@ func TestServerWithProtectionDisabled(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode:     UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{Enabled: false},
 		},
 		ServePlainDNS: true,
@@ -478,7 +484,8 @@ func TestServerRace(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
-			UpstreamDNS: []string{"8.8.8.8:53", "8.8.4.4:53"},
+			UpstreamMode: UpstreamModeLoadBalance,
+			UpstreamDNS:  []string{"8.8.8.8:53", "8.8.4.4:53"},
 		},
 		ConfigModified: func() {},
 		ServePlainDNS:  true,
@@ -531,6 +538,7 @@ func TestSafeSearch(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -614,6 +622,7 @@ func TestInvalidRequest(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -643,6 +652,7 @@ func TestBlockedRequest(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -678,7 +688,8 @@ func TestServerCustomClientUpstream(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
-			CacheSize: defaultCacheSize,
+			CacheSize:    defaultCacheSize,
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -756,6 +767,7 @@ func TestBlockCNAMEProtectionEnabled(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -789,6 +801,7 @@ func TestBlockCNAME(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -864,6 +877,7 @@ func TestClientRulesForCNAMEMatching(t *testing.T) {
 			FilterHandler: func(_ netip.Addr, _ string, settings *filtering.Settings) {
 				settings.FilteringEnabled = false
 			},
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -909,6 +923,7 @@ func TestNullBlockedRequest(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -974,7 +989,8 @@ func TestBlockedCustomIP(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
-			UpstreamDNS: []string{"8.8.8.8:53", "8.8.4.4:53"},
+			UpstreamDNS:  []string{"8.8.8.8:53", "8.8.4.4:53"},
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -1027,6 +1043,7 @@ func TestBlockedByHosts(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -1078,6 +1095,7 @@ func TestBlockedBySafeBrowsing(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -1136,7 +1154,8 @@ func TestRewrite(t *testing.T) {
 		UDPListenAddrs: []*net.UDPAddr{{}},
 		TCPListenAddrs: []*net.TCPAddr{{}},
 		Config: Config{
-			UpstreamDNS: []string{"8.8.8.8:53"},
+			UpstreamDNS:  []string{"8.8.8.8:53"},
+			UpstreamMode: UpstreamModeLoadBalance,
 			EDNSClientSubnet: &EDNSClientSubnet{
 				Enabled: false,
 			},
@@ -1265,6 +1284,7 @@ func TestPTRResponseFromDHCPLeases(t *testing.T) {
 	s.conf.TCPListenAddrs = []*net.TCPAddr{{}}
 	s.conf.UpstreamDNS = []string{"127.0.0.1:53"}
 	s.conf.Config.EDNSClientSubnet = &EDNSClientSubnet{Enabled: false}
+	s.conf.Config.UpstreamMode = UpstreamModeLoadBalance
 
 	err = s.Prepare(&s.conf)
 	require.NoError(t, err)
@@ -1347,6 +1367,7 @@ func TestPTRResponseFromHosts(t *testing.T) {
 	s.conf.TCPListenAddrs = []*net.TCPAddr{{}}
 	s.conf.UpstreamDNS = []string{"127.0.0.1:53"}
 	s.conf.Config.EDNSClientSubnet = &EDNSClientSubnet{Enabled: false}
+	s.conf.Config.UpstreamMode = UpstreamModeLoadBalance
 
 	err = s.Prepare(&s.conf)
 	require.NoError(t, err)