Feature/permanent dns (netbirdio#967)

* Add DNS list argument for mobile client

* Write testable code

Many places are checked the wgInterface != nil condition.
It is doing it just because to avoid the real wgInterface creation for tests.
Instead of this involve a wgInterface interface what is moc-able.

* Refactor the DNS server internal code structure

With the fake resolver has been involved several
if-else statement and generated some unused
variables to distinguish the listener and fake
resolver solutions at running time. With this
commit the fake resolver and listener based
solution has been moved into two separated
structure. Name of this layer is the 'service'.
With this modification the unit test looks
simpler and open the option to add new logic for
the permanent DNS service usage for mobile
systems.



* Remove is running check in test

We can not ensure the state well so remove this
check. The test will fail if the server is not
running well.

client/android/client.go

@@ -7,6 +7,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	"github.com/netbirdio/netbird/client/internal"
+	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/routemanager"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
@@ -35,6 +36,11 @@ type RouteListener interface {
 	routemanager.RouteListener
 }
 
+// DnsReadyListener export internal dns ReadyListener for mobile
+type DnsReadyListener interface {
+	dns.ReadyListener
+}
+
 func init() {
 	formatter.SetLogcatFormatter(log.StandardLogger())
 }
@@ -49,6 +55,7 @@ type Client struct {
 	ctxCancelLock *sync.Mutex
 	deviceName    string
 	routeListener routemanager.RouteListener
+	onHostDnsFn   func([]string)
 }
 
 // NewClient instantiate a new Client
@@ -65,7 +72,7 @@ func NewClient(cfgFile, deviceName string, tunAdapter TunAdapter, iFaceDiscover
 }
 
 // Run start the internal client. It is a blocker function
-func (c *Client) Run(urlOpener URLOpener) error {
+func (c *Client) Run(urlOpener URLOpener, dns *DNSList, dnsReadyListener DnsReadyListener) error {
 	cfg, err := internal.UpdateOrCreateConfig(internal.ConfigInput{
 		ConfigPath: c.cfgFile,
 	})
@@ -90,7 +97,8 @@ func (c *Client) Run(urlOpener URLOpener) error {
 
 	// todo do not throw error in case of cancelled context
 	ctx = internal.CtxInitState(ctx)
-	return internal.RunClient(ctx, cfg, c.recorder, c.tunAdapter, c.iFaceDiscover, c.routeListener)
+	c.onHostDnsFn = func([]string) {}
+	return internal.RunClientMobile(ctx, cfg, c.recorder, c.tunAdapter, c.iFaceDiscover, c.routeListener, dns.items, dnsReadyListener)
 }
 
 // Stop the internal client and free the resources
@@ -126,6 +134,17 @@ func (c *Client) PeersList() *PeerInfoArray {
 	return &PeerInfoArray{items: peerInfos}
 }
 
+// OnUpdatedHostDNS update the DNS servers addresses for root zones
+func (c *Client) OnUpdatedHostDNS(list *DNSList) error {
+	dnsServer, err := dns.GetServerDns()
+	if err != nil {
+		return err
+	}
+
+	dnsServer.OnUpdatedHostDNSServer(list.items)
+	return nil
+}
+
 // SetConnectionListener set the network connection listener
 func (c *Client) SetConnectionListener(listener ConnectionListener) {
 	c.recorder.SetConnectionListener(listener)

client/android/dns_list.go

@@ -0,0 +1,26 @@
+package android
+
+import "fmt"
+
+// DNSList is a wrapper of []string
+type DNSList struct {
+	items []string
+}
+
+// Add new DNS address to the collection
+func (array *DNSList) Add(s string) {
+	array.items = append(array.items, s)
+}
+
+// Get return an element of the collection
+func (array *DNSList) Get(i int) (string, error) {
+	if i >= len(array.items) || i < 0 {
+		return "", fmt.Errorf("out of range")
+	}
+	return array.items[i], nil
+}
+
+// Size return with the size of the collection
+func (array *DNSList) Size() int {
+	return len(array.items)
+}

client/android/dns_list_test.go

@@ -0,0 +1,24 @@
+package android
+
+import "testing"
+
+func TestDNSList_Get(t *testing.T) {
+	l := DNSList{
+		items: make([]string, 1),
+	}
+
+	_, err := l.Get(0)
+	if err != nil {
+		t.Errorf("invalid error: %s", err)
+	}
+
+	_, err = l.Get(-1)
+	if err == nil {
+		t.Errorf("expected error but got nil")
+	}
+
+	_, err = l.Get(1)
+	if err == nil {
+		t.Errorf("expected error but got nil")
+	}
+}

client/cmd/up.go

@@ -104,7 +104,7 @@ func runInForegroundMode(ctx context.Context, cmd *cobra.Command) error {
 	var cancel context.CancelFunc
 	ctx, cancel = context.WithCancel(ctx)
 	SetupCloseHandler(ctx, cancel)
-	return internal.RunClient(ctx, config, peer.NewRecorder(config.ManagementURL.String()), nil, nil, nil)
+	return internal.RunClient(ctx, config, peer.NewRecorder(config.ManagementURL.String()))
 }
 
 func runInDaemonMode(ctx context.Context, cmd *cobra.Command) error {

client/internal/connect.go

@@ -12,6 +12,7 @@ import (
 	"google.golang.org/grpc/codes"
 	gstatus "google.golang.org/grpc/status"
 
+	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/routemanager"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
@@ -24,7 +25,24 @@ import (
 )
 
 // RunClient with main logic.
-func RunClient(ctx context.Context, config *Config, statusRecorder *peer.Status, tunAdapter iface.TunAdapter, iFaceDiscover stdnet.ExternalIFaceDiscover, routeListener routemanager.RouteListener) error {
+func RunClient(ctx context.Context, config *Config, statusRecorder *peer.Status) error {
+	return runClient(ctx, config, statusRecorder, MobileDependency{})
+}
+
+// RunClientMobile with main logic on mobile system
+func RunClientMobile(ctx context.Context, config *Config, statusRecorder *peer.Status, tunAdapter iface.TunAdapter, iFaceDiscover stdnet.ExternalIFaceDiscover, routeListener routemanager.RouteListener, dnsAddresses []string, dnsReadyListener dns.ReadyListener) error {
+	// in case of non Android os these variables will be nil
+	mobileDependency := MobileDependency{
+		TunAdapter:       tunAdapter,
+		IFaceDiscover:    iFaceDiscover,
+		RouteListener:    routeListener,
+		HostDNSAddresses: dnsAddresses,
+		DnsReadyListener: dnsReadyListener,
+	}
+	return runClient(ctx, config, statusRecorder, mobileDependency)
+}
+
+func runClient(ctx context.Context, config *Config, statusRecorder *peer.Status, mobileDependency MobileDependency) error {
 	backOff := &backoff.ExponentialBackOff{
 		InitialInterval:     time.Second,
 		RandomizationFactor: 1,
@@ -151,14 +169,7 @@ func RunClient(ctx context.Context, config *Config, statusRecorder *peer.Status,
 			return wrapErr(err)
 		}
 
-		// in case of non Android os these variables will be nil
-		md := MobileDependency{
-			TunAdapter:    tunAdapter,
-			IFaceDiscover: iFaceDiscover,
-			RouteListener: routeListener,
-		}
-
-		engine := NewEngine(engineCtx, cancel, signalClient, mgmClient, engineConfig, md, statusRecorder)
+		engine := NewEngine(engineCtx, cancel, signalClient, mgmClient, engineConfig, mobileDependency, statusRecorder)
 		err = engine.Start()
 		if err != nil {
 			log.Errorf("error while starting Netbird Connection Engine: %s", err)

client/internal/dns/host_android.go

@@ -1,13 +1,9 @@
 package dns
 
-import (
-	"github.com/netbirdio/netbird/iface"
-)
-
 type androidHostManager struct {
 }
 
-func newHostManager(wgInterface *iface.WGIface) (hostManager, error) {
+func newHostManager(wgInterface WGIface) (hostManager, error) {
 	return &androidHostManager{}, nil
 }
 

client/internal/dns/host_darwin.go

@@ -9,8 +9,6 @@ import (
 	"strings"
 
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const (
@@ -34,7 +32,7 @@ type systemConfigurator struct {
 	createdKeys      map[string]struct{}
 }
 
-func newHostManager(_ *iface.WGIface) (hostManager, error) {
+func newHostManager(_ WGIface) (hostManager, error) {
 	return &systemConfigurator{
 		createdKeys: make(map[string]struct{}),
 	}, nil

client/internal/dns/host_linux.go

@@ -5,10 +5,10 @@ package dns
 import (
 	"bufio"
 	"fmt"
-	"github.com/netbirdio/netbird/iface"
-	log "github.com/sirupsen/logrus"
 	"os"
 	"strings"
+
+	log "github.com/sirupsen/logrus"
 )
 
 const (
@@ -25,7 +25,7 @@ const (
 
 type osManagerType int
 
-func newHostManager(wgInterface *iface.WGIface) (hostManager, error) {
+func newHostManager(wgInterface WGIface) (hostManager, error) {
 	osManager, err := getOSDNSManagerType()
 	if err != nil {
 		return nil, err

client/internal/dns/host_windows.go

@@ -6,8 +6,6 @@ import (
 
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sys/windows/registry"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const (
@@ -33,7 +31,7 @@ type registryConfigurator struct {
 	existingSearchDomains []string
 }
 
-func newHostManager(wgInterface *iface.WGIface) (hostManager, error) {
+func newHostManager(wgInterface WGIface) (hostManager, error) {
 	guid, err := wgInterface.GetInterfaceGUIDString()
 	if err != nil {
 		return nil, err

client/internal/dns/mockServer.go

@@ -31,6 +31,11 @@ func (m *MockServer) DnsIP() string {
 	return ""
 }
 
+func (m *MockServer) OnUpdatedHostDNSServer(strings []string) {
+	//TODO implement me
+	panic("implement me")
+}
+
 // UpdateDNSServer mock implementation of UpdateDNSServer from Server interface
 func (m *MockServer) UpdateDNSServer(serial uint64, update nbdns.Config) error {
 	if m.UpdateDNSServerFunc != nil {

client/internal/dns/network_manager_linux.go

@@ -14,8 +14,6 @@ import (
 	"github.com/hashicorp/go-version"
 	"github.com/miekg/dns"
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const (
@@ -72,7 +70,7 @@ func (s networkManagerConnSettings) cleanDeprecatedSettings() {
 	}
 }
 
-func newNetworkManagerDbusConfigurator(wgInterface *iface.WGIface) (hostManager, error) {
+func newNetworkManagerDbusConfigurator(wgInterface WGIface) (hostManager, error) {
 	obj, closeConn, err := getDbusObject(networkManagerDest, networkManagerDbusObjectNode)
 	if err != nil {
 		return nil, err

client/internal/dns/resolvconf_linux.go

@@ -8,8 +8,6 @@ import (
 	"strings"
 
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/iface"
 )
 
 const resolvconfCommand = "resolvconf"
@@ -18,7 +16,7 @@ type resolvconf struct {
 	ifaceName string
 }
 
-func newResolvConfConfigurator(wgInterface *iface.WGIface) (hostManager, error) {
+func newResolvConfConfigurator(wgInterface WGIface) (hostManager, error) {
 	return &resolvconf{
 		ifaceName: wgInterface.Name(),
 	}, nil