Update contrib/mobile for the latest iOS build

contrib/mobile/build

@@ -37,7 +37,7 @@ if [ $IOS ]; then
   echo "Building framework for iOS"
   go get golang.org/x/mobile/bind
   gomobile bind \
-    -target ios -tags mobile -o Yggdrasil.xcframework \
+    -target ios,macos -tags mobile -o Yggdrasil.xcframework \
     -ldflags="$LDFLAGS $STRIP" -gcflags="$GCFLAGS" \
     ./contrib/mobile ./src/config;
 fi

contrib/mobile/mobile.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 	"regexp"
+	"runtime/debug"
 
 	"github.com/gologme/log"
 
@@ -15,6 +16,7 @@ import (
 	"github.com/yggdrasil-network/yggdrasil-go/src/defaults"
 	"github.com/yggdrasil-network/yggdrasil-go/src/ipv6rwc"
 	"github.com/yggdrasil-network/yggdrasil-go/src/multicast"
+	"github.com/yggdrasil-network/yggdrasil-go/src/tun"
 	"github.com/yggdrasil-network/yggdrasil-go/src/version"
 
 	_ "golang.org/x/mobile/bind"
@@ -30,7 +32,9 @@ type Yggdrasil struct {
 	iprwc     *ipv6rwc.ReadWriteCloser
 	config    *config.NodeConfig
 	multicast *multicast.Multicast
+	tun       *tun.TunAdapter // optional
 	log       MobileLogger
+	logger    *log.Logger
 }
 
 // StartAutoconfigure starts a node with a randomly generated config
@@ -41,10 +45,12 @@ func (m *Yggdrasil) StartAutoconfigure() error {
 // StartJSON starts a node with the given JSON config. You can get JSON config
 // (rather than HJSON) by using the GenerateConfigJSON() function
 func (m *Yggdrasil) StartJSON(configjson []byte) error {
-	logger := log.New(m.log, "", 0)
-	logger.EnableLevel("error")
-	logger.EnableLevel("warn")
-	logger.EnableLevel("info")
+	debug.SetMemoryLimit(1024 * 1024 * 40)
+
+	m.logger = log.New(m.log, "", 0)
+	m.logger.EnableLevel("error")
+	m.logger.EnableLevel("warn")
+	m.logger.EnableLevel("info")
 	m.config = defaults.GenerateConfig()
 	if err := json.Unmarshal(configjson, &m.config); err != nil {
 		return err
@@ -71,7 +77,7 @@ func (m *Yggdrasil) StartJSON(configjson []byte) error {
 			}
 			options = append(options, core.AllowedPublicKey(k[:]))
 		}
-		m.core, err = core.New(sk[:], logger, options...)
+		m.core, err = core.New(sk[:], m.logger, options...)
 		if err != nil {
 			panic(err)
 		}
@@ -90,9 +96,9 @@ func (m *Yggdrasil) StartJSON(configjson []byte) error {
 				Priority: uint8(intf.Priority),
 			})
 		}
-		m.multicast, err = multicast.New(m.core, logger, options...)
+		m.multicast, err = multicast.New(m.core, m.logger, options...)
 		if err != nil {
-			logger.Errorln("An error occurred starting multicast:", err)
+			m.logger.Errorln("An error occurred starting multicast:", err)
 		}
 	}
 
@@ -155,6 +161,11 @@ func (m *Yggdrasil) Stop() error {
 	if err := m.multicast.Stop(); err != nil {
 		return err
 	}
+	if m.tun != nil {
+		if err := m.tun.Stop(); err != nil {
+			return err
+		}
+	}
 	m.core.Stop()
 	return nil
 }

contrib/mobile/mobile_ios.go

@@ -15,6 +15,8 @@ void Log(const char *text) {
 import "C"
 import (
 	"unsafe"
+
+	"github.com/yggdrasil-network/yggdrasil-go/src/tun"
 )
 
 type MobileLogger struct {
@@ -26,3 +28,13 @@ func (nsl MobileLogger) Write(p []byte) (n int, err error) {
 	C.Log(cstr)
 	return len(p), nil
 }
+
+func (m *Yggdrasil) TakeOverTUN(fd int32) error {
+	options := []tun.SetupOption{
+		tun.FileDescriptor(fd),
+		tun.InterfaceMTU(m.iprwc.MTU()),
+	}
+	var err error
+	m.tun, err = tun.New(m.iprwc, m.logger, options...)
+	return err
+}

src/tun/options.go

@@ -6,6 +6,8 @@ func (m *TunAdapter) _applyOption(opt SetupOption) {
 		m.config.name = v
 	case InterfaceMTU:
 		m.config.mtu = v
+	case FileDescriptor:
+		m.config.fd = int32(v)
 	}
 }
 
@@ -15,6 +17,8 @@ type SetupOption interface {
 
 type InterfaceName string
 type InterfaceMTU uint64
+type FileDescriptor int32
 
 func (a InterfaceName) isSetupOption()  {}
 func (a InterfaceMTU) isSetupOption()   {}
+func (a FileDescriptor) isSetupOption() {}

src/tun/tun.go

@@ -37,6 +37,7 @@ type TunAdapter struct {
 	isOpen    bool
 	isEnabled bool // Used by the writer to drop sessionTraffic if not enabled
 	config    struct {
+		fd   int32
 		name InterfaceName
 		mtu  InterfaceMTU
 	}
@@ -119,7 +120,13 @@ func (tun *TunAdapter) _start() error {
 	if tun.rwc.MaxMTU() < mtu {
 		mtu = tun.rwc.MaxMTU()
 	}
-	if err := tun.setup(string(tun.config.name), addr, mtu); err != nil {
+	var err error
+	if tun.config.fd > 0 {
+		err = tun.setupFD(tun.config.fd, addr, mtu)
+	} else {
+		err = tun.setup(string(tun.config.name), addr, mtu)
+	}
+	if err != nil {
 		return err
 	}
 	if tun.MTU() != mtu {

src/tun/tun_darwin.go

@@ -1,5 +1,5 @@
-//go:build !mobile
-// +build !mobile
+//go:build darwin || ios
+// +build darwin ios
 
 package tun
 
@@ -7,6 +7,7 @@ package tun
 
 import (
 	"encoding/binary"
+	"os"
 	"strconv"
 	"strings"
 	"unsafe"
@@ -34,6 +35,31 @@ func (tun *TunAdapter) setup(ifname string, addr string, mtu uint64) error {
 	return tun.setupAddress(addr)
 }
 
+// Configures the "utun" adapter from an existing file descriptor.
+func (tun *TunAdapter) setupFD(fd int32, addr string, mtu uint64) error {
+	dfd, err := unix.Dup(int(fd))
+	if err != nil {
+		return err
+	}
+	err = unix.SetNonblock(dfd, true)
+	if err != nil {
+		unix.Close(dfd)
+		return err
+	}
+	iface, err := wgtun.CreateTUNFromFile(os.NewFile(uintptr(dfd), "/dev/tun"), 0)
+	if err != nil {
+		unix.Close(dfd)
+		return err
+	}
+	tun.iface = iface
+	if m, err := iface.MTU(); err == nil {
+		tun.mtu = getSupportedMTU(uint64(m))
+	} else {
+		tun.mtu = 0
+	}
+	return nil // tun.setupAddress(addr)
+}
+
 const (
 	darwin_SIOCAIFADDR_IN6       = 2155899162 // netinet6/in6_var.h
 	darwin_IN6_IFF_NODAD         = 0x0020     // netinet6/in6_var.h