[client] Add embeddable library (#3239)

client/iface/iface.go

@@ -9,6 +9,7 @@ import (
 	"github.com/hashicorp/go-multierror"
 	"github.com/pion/transport/v3"
 	log "github.com/sirupsen/logrus"
+	"golang.zx2c4.com/wireguard/tun/netstack"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 
 	wgdevice "golang.zx2c4.com/wireguard/device"
@@ -241,3 +242,11 @@ func (w *WGIface) waitUntilRemoved() error {
 		}
 	}
 }
+
+// GetNet returns the netstack.Net for the netstack device
+func (w *WGIface) GetNet() *netstack.Net {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	return w.tun.GetNet()
+}