Feature/dns client configuration (#563)

Added host configurators for Linux, Windows, and macOS.

The host configurator will update the peer system configuration
 directing DNS queries according to its capabilities.

Some Linux distributions don't support split (match) DNS or custom ports,
 and that will be reported to our management system in another PR

client/internal/dns/server_test.go

@@ -3,6 +3,7 @@ package dns
 import (
 	"context"
 	"fmt"
+	"github.com/miekg/dns"
 	nbdns "github.com/netbirdio/netbird/dns"
 	"net"
 	"net/netip"
@@ -74,12 +75,12 @@ func TestUpdateDNSServer(t *testing.T) {
 				},
 			},
 			expectedUpstreamMap: registrationMap{"netbird.io": struct{}{}, "netbird.cloud": struct{}{}, nbdns.RootZone: struct{}{}},
-			expectedLocalMap:    registrationMap{zoneRecords[0].Name: struct{}{}},
+			expectedLocalMap:    registrationMap{buildRecordKey(zoneRecords[0].Name, 1, 1): struct{}{}},
 		},
 		{
 			name:            "New Config Should Succeed",
 			initLocalMap:    registrationMap{"netbird.cloud": struct{}{}},
-			initUpstreamMap: registrationMap{zoneRecords[0].Name: struct{}{}},
+			initUpstreamMap: registrationMap{buildRecordKey(zoneRecords[0].Name, 1, 1): struct{}{}},
 			initSerial:      0,
 			inputSerial:     1,
 			inputUpdate: nbdns.Config{
@@ -98,7 +99,7 @@ func TestUpdateDNSServer(t *testing.T) {
 				},
 			},
 			expectedUpstreamMap: registrationMap{"netbird.io": struct{}{}, "netbird.cloud": struct{}{}},
-			expectedLocalMap:    registrationMap{zoneRecords[0].Name: struct{}{}},
+			expectedLocalMap:    registrationMap{buildRecordKey(zoneRecords[0].Name, 1, 1): struct{}{}},
 		},
 		{
 			name:            "Smaller Config Serial Should Be Skipped",
@@ -188,12 +189,14 @@ func TestUpdateDNSServer(t *testing.T) {
 
 	for _, testCase := range testCases {
 		t.Run(testCase.name, func(t *testing.T) {
-			ctx := context.Background()
-			dnsServer := NewDefaultServer(ctx)
+			dnsServer := getDefaultServerWithNoHostManager("127.0.0.1")
+
+			dnsServer.hostManager = newNoopHostMocker()
 
 			dnsServer.dnsMuxMap = testCase.initUpstreamMap
 			dnsServer.localResolver.registeredMap = testCase.initLocalMap
 			dnsServer.updateSerial = testCase.initSerial
+			// pretend we are running
 			dnsServer.listenerIsRunning = true
 
 			err := dnsServer.UpdateDNSServer(testCase.inputSerial, testCase.inputUpdate)
@@ -230,13 +233,15 @@ func TestUpdateDNSServer(t *testing.T) {
 }
 
 func TestDNSServerStartStop(t *testing.T) {
-	ctx := context.Background()
-	dnsServer := NewDefaultServer(ctx)
+	dnsServer := getDefaultServerWithNoHostManager("127.0.0.1")
+
 	if runtime.GOOS == "windows" && os.Getenv("CI") == "true" {
 		// todo review why this test is not working only on github actions workflows
 		t.Skip("skipping test in Windows CI workflows.")
 	}
 
+	dnsServer.hostManager = newNoopHostMocker()
+
 	dnsServer.Start()
 
 	err := dnsServer.localResolver.registerRecord(zoneRecords[0])
@@ -276,10 +281,40 @@ func TestDNSServerStartStop(t *testing.T) {
 	}
 
 	dnsServer.Stop()
-	ctx, cancel := context.WithTimeout(ctx, time.Second*1)
+	ctx, cancel := context.WithTimeout(context.TODO(), time.Second*1)
 	defer cancel()
 	_, err = resolver.LookupHost(ctx, zoneRecords[0].Name)
 	if err == nil {
 		t.Fatalf("we should encounter an error when querying a stopped server")
 	}
 }
+
+func getDefaultServerWithNoHostManager(ip string) *DefaultServer {
+	mux := dns.NewServeMux()
+	listenIP := defaultIP
+	if ip != "" {
+		listenIP = ip
+	}
+
+	dnsServer := &dns.Server{
+		Addr:    fmt.Sprintf("%s:%d", ip, port),
+		Net:     "udp",
+		Handler: mux,
+		UDPSize: 65535,
+	}
+
+	ctx, stop := context.WithCancel(context.TODO())
+
+	return &DefaultServer{
+		ctx:       ctx,
+		stop:      stop,
+		server:    dnsServer,
+		dnsMux:    mux,
+		dnsMuxMap: make(registrationMap),
+		localResolver: &localResolver{
+			registeredMap: make(registrationMap),
+		},
+		runtimePort: port,
+		runtimeIP:   listenIP,
+	}
+}