[client] Refactor/iface pkg (#2646)

Refactor the flat code structure

client/iface/iface_darwin.go

@@ -0,0 +1,67 @@
+//go:build !ios
+
+package iface
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/cenkalti/backoff/v4"
+	"github.com/pion/transport/v3"
+
+	"github.com/netbirdio/netbird/client/iface/bind"
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/netstack"
+)
+
+// NewWGIFace Creates a new WireGuard interface instance
+func NewWGIFace(iFaceName string, address string, wgPort int, wgPrivKey string, mtu int, transportNet transport.Net, _ *device.MobileIFaceArguments, filterFn bind.FilterFn) (*WGIface, error) {
+	wgAddress, err := device.ParseWGAddress(address)
+	if err != nil {
+		return nil, err
+	}
+
+	wgIFace := &WGIface{
+		userspaceBind: true,
+	}
+
+	if netstack.IsEnabled() {
+		wgIFace.tun = device.NewNetstackDevice(iFaceName, wgAddress, wgPort, wgPrivKey, mtu, transportNet, netstack.ListenAddr(), filterFn)
+		return wgIFace, nil
+	}
+
+	wgIFace.tun = device.NewTunDevice(iFaceName, wgAddress, wgPort, wgPrivKey, mtu, transportNet, filterFn)
+
+	return wgIFace, nil
+}
+
+// CreateOnAndroid this function make sense on mobile only
+func (w *WGIface) CreateOnAndroid([]string, string, []string) error {
+	return fmt.Errorf("this function has not implemented on this platform")
+}
+
+// Create creates a new Wireguard interface, sets a given IP and brings it up.
+// Will reuse an existing one.
+// this function is different on Android
+func (w *WGIface) Create() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	backOff := &backoff.ExponentialBackOff{
+		InitialInterval: 20 * time.Millisecond,
+		MaxElapsedTime:  500 * time.Millisecond,
+		Stop:            backoff.Stop,
+		Clock:           backoff.SystemClock,
+	}
+
+	operation := func() error {
+		cfgr, err := w.tun.Create()
+		if err != nil {
+			return err
+		}
+		w.configurer = cfgr
+		return nil
+	}
+
+	return backoff.Retry(operation, backOff)
+}