Fix interface monitor for android

adapter/router.go

@@ -32,6 +32,7 @@ type Router interface {
 	LookupDefault(ctx context.Context, domain string) ([]netip.Addr, error)
 
 	InterfaceFinder() control.InterfaceFinder
+	UpdateInterfaces() error
 	DefaultInterface() string
 	AutoDetectInterface() bool
 	AutoDetectInterfaceFunc() control.Func

box.go

@@ -133,6 +133,12 @@ func New(options Options) (*Box, error) {
 	if err != nil {
 		return nil, err
 	}
+	if options.PlatformInterface != nil {
+		err = options.PlatformInterface.Initialize(ctx, router)
+		if err != nil {
+			return nil, E.Cause(err, "initialize platform interface")
+		}
+	}
 	preServices := make(map[string]adapter.Service)
 	postServices := make(map[string]adapter.Service)
 	if needClashAPI {

experimental/libbox/iterator.go

@@ -29,3 +29,19 @@ func (i *iterator[T]) Next() T {
 func (i *iterator[T]) HasNext() bool {
 	return len(i.values) > 0
 }
+
+type abstractIterator[T any] interface {
+	Next() T
+	HasNext() bool
+}
+
+func iteratorToArray[T any](iterator abstractIterator[T]) []T {
+	if iterator == nil {
+		return nil
+	}
+	var values []T
+	for iterator.HasNext() {
+		values = append(values, iterator.Next())
+	}
+	return values
+}

experimental/libbox/monitor.go

@@ -0,0 +1,183 @@
+package libbox
+
+import (
+	"context"
+	"net"
+	"net/netip"
+	"sync"
+
+	"github.com/sagernet/sing-tun"
+	"github.com/sagernet/sing/common"
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+	"github.com/sagernet/sing/common/x/list"
+)
+
+var (
+	_ tun.DefaultInterfaceMonitor = (*platformDefaultInterfaceMonitor)(nil)
+	_ InterfaceUpdateListener     = (*platformDefaultInterfaceMonitor)(nil)
+)
+
+type platformDefaultInterfaceMonitor struct {
+	*platformInterfaceWrapper
+	errorHandler          E.Handler
+	networkAddresses      []networkAddress
+	defaultInterfaceName  string
+	defaultInterfaceIndex int
+	element               *list.Element[tun.NetworkUpdateCallback]
+	access                sync.Mutex
+	callbacks             list.List[tun.DefaultInterfaceUpdateCallback]
+}
+
+type networkAddress struct {
+	interfaceName  string
+	interfaceIndex int
+	addresses      []netip.Prefix
+}
+
+func (m *platformDefaultInterfaceMonitor) Start() error {
+	return m.iif.StartDefaultInterfaceMonitor(m)
+}
+
+func (m *platformDefaultInterfaceMonitor) Close() error {
+	return m.iif.CloseDefaultInterfaceMonitor(m)
+}
+
+func (m *platformDefaultInterfaceMonitor) DefaultInterfaceName(destination netip.Addr) string {
+	for _, address := range m.networkAddresses {
+		for _, prefix := range address.addresses {
+			if prefix.Contains(destination) {
+				return address.interfaceName
+			}
+		}
+	}
+	return m.defaultInterfaceName
+}
+
+func (m *platformDefaultInterfaceMonitor) DefaultInterfaceIndex(destination netip.Addr) int {
+	for _, address := range m.networkAddresses {
+		for _, prefix := range address.addresses {
+			if prefix.Contains(destination) {
+				return address.interfaceIndex
+			}
+		}
+	}
+	return m.defaultInterfaceIndex
+}
+
+func (m *platformDefaultInterfaceMonitor) OverrideAndroidVPN() bool {
+	return false
+}
+
+func (m *platformDefaultInterfaceMonitor) AndroidVPNEnabled() bool {
+	return false
+}
+
+func (m *platformDefaultInterfaceMonitor) RegisterCallback(callback tun.DefaultInterfaceUpdateCallback) *list.Element[tun.DefaultInterfaceUpdateCallback] {
+	m.access.Lock()
+	defer m.access.Unlock()
+	return m.callbacks.PushBack(callback)
+}
+
+func (m *platformDefaultInterfaceMonitor) UnregisterCallback(element *list.Element[tun.DefaultInterfaceUpdateCallback]) {
+	m.access.Lock()
+	defer m.access.Unlock()
+	m.callbacks.Remove(element)
+}
+
+func (m *platformDefaultInterfaceMonitor) UpdateDefaultInterface(interfaceName string, interfaceIndex32 int32) {
+	var err error
+	if m.iif.UsePlatformInterfaceGetter() {
+		err = m.updateInterfacesPlatform()
+	} else {
+		err = m.updateInterfaces()
+	}
+	if err == nil {
+		err = m.router.UpdateInterfaces()
+	}
+	if err != nil {
+		m.errorHandler.NewError(context.Background(), E.Cause(err, "update interfaces"))
+	}
+	interfaceIndex := int(interfaceIndex32)
+	if interfaceName == "" {
+		for _, netIf := range m.networkAddresses {
+			if netIf.interfaceIndex == interfaceIndex {
+				interfaceName = netIf.interfaceName
+				break
+			}
+		}
+	} else if interfaceIndex == -1 {
+		for _, netIf := range m.networkAddresses {
+			if netIf.interfaceName == interfaceName {
+				interfaceIndex = netIf.interfaceIndex
+				break
+			}
+		}
+	}
+	if interfaceName == "" {
+		m.errorHandler.NewError(context.Background(), E.New("invalid interface name for ", interfaceIndex))
+		return
+	} else if interfaceIndex == -1 {
+		m.errorHandler.NewError(context.Background(), E.New("invalid interface index for ", interfaceName))
+		return
+	}
+	if m.defaultInterfaceName == interfaceName && m.defaultInterfaceIndex == interfaceIndex {
+		return
+	}
+	m.defaultInterfaceName = interfaceName
+	m.defaultInterfaceIndex = interfaceIndex
+	m.access.Lock()
+	callbacks := m.callbacks.Array()
+	m.access.Unlock()
+	for _, callback := range callbacks {
+		err = callback(tun.EventInterfaceUpdate)
+		if err != nil {
+			m.errorHandler.NewError(context.Background(), err)
+		}
+	}
+}
+
+func (m *platformDefaultInterfaceMonitor) updateInterfaces() error {
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		return err
+	}
+	var addresses []networkAddress
+	for _, iif := range interfaces {
+		var netAddresses []net.Addr
+		netAddresses, err = iif.Addrs()
+		if err != nil {
+			return err
+		}
+		var address networkAddress
+		address.interfaceName = iif.Name
+		address.interfaceIndex = iif.Index
+		address.addresses = common.Map(common.FilterIsInstance(netAddresses, func(it net.Addr) (*net.IPNet, bool) {
+			value, loaded := it.(*net.IPNet)
+			return value, loaded
+		}), func(it *net.IPNet) netip.Prefix {
+			bits, _ := it.Mask.Size()
+			return netip.PrefixFrom(M.AddrFromIP(it.IP), bits)
+		})
+		addresses = append(addresses, address)
+	}
+	m.networkAddresses = addresses
+	return nil
+}
+
+func (m *platformDefaultInterfaceMonitor) updateInterfacesPlatform() error {
+	interfaces, err := m.Interfaces()
+	if err != nil {
+		return err
+	}
+	var addresses []networkAddress
+	for _, iif := range interfaces {
+		var address networkAddress
+		address.interfaceName = iif.Name
+		address.interfaceIndex = iif.Index
+		// address.addresses = common.Map(iif.Addresses, netip.MustParsePrefix)
+		addresses = append(addresses, address)
+	}
+	m.networkAddresses = addresses
+	return nil
+}

experimental/libbox/platform.go

@@ -1,6 +1,8 @@
 package libbox
 
-import "github.com/sagernet/sing-box/option"
+import (
+	"github.com/sagernet/sing-box/option"
+)
 
 type PlatformInterface interface {
 	AutoDetectInterfaceControl(fd int32) error
@@ -10,6 +12,11 @@ type PlatformInterface interface {
 	FindConnectionOwner(ipProtocol int32, sourceAddress string, sourcePort int32, destinationAddress string, destinationPort int32) (int32, error)
 	PackageNameByUid(uid int32) (string, error)
 	UIDByPackageName(packageName string) (int32, error)
+	UsePlatformDefaultInterfaceMonitor() bool
+	StartDefaultInterfaceMonitor(listener InterfaceUpdateListener) error
+	CloseDefaultInterfaceMonitor(listener InterfaceUpdateListener) error
+	UsePlatformInterfaceGetter() bool
+	GetInterfaces() (NetworkInterfaceIterator, error)
 }
 
 type TunInterface interface {
@@ -17,8 +24,19 @@ type TunInterface interface {
 	Close() error
 }
 
-type OnDemandRuleIterator interface {
+type InterfaceUpdateListener interface {
-	Next() OnDemandRule
+	UpdateDefaultInterface(interfaceName string, interfaceIndex int32)
+}
+
+type NetworkInterface struct {
+	Index     int32
+	MTU       int32
+	Name      string
+	Addresses StringIterator
+}
+
+type NetworkInterfaceIterator interface {
+	Next() *NetworkInterface
 	HasNext() bool
 }
 
@@ -31,6 +49,11 @@ type OnDemandRule interface {
 	ProbeURL() string
 }
 
+type OnDemandRuleIterator interface {
+	Next() OnDemandRule
+	HasNext() bool
+}
+
 type onDemandRule struct {
 	option.OnDemandRule
 }

experimental/libbox/platform/interface.go

@@ -1,17 +1,33 @@
 package platform
 
 import (
+	"context"
 	"io"
+	"net/netip"
 
+	"github.com/sagernet/sing-box/adapter"
 	"github.com/sagernet/sing-box/common/process"
 	"github.com/sagernet/sing-box/option"
 	"github.com/sagernet/sing-tun"
 	"github.com/sagernet/sing/common/control"
+	E "github.com/sagernet/sing/common/exceptions"
 )
 
 type Interface interface {
+	Initialize(ctx context.Context, router adapter.Router) error
 	AutoDetectInterfaceControl() control.Func
 	OpenTun(options *tun.Options, platformOptions option.TunPlatformOptions) (tun.Tun, error)
+	UsePlatformDefaultInterfaceMonitor() bool
+	CreateDefaultInterfaceMonitor(errorHandler E.Handler) tun.DefaultInterfaceMonitor
+	UsePlatformInterfaceGetter() bool
+	Interfaces() ([]NetworkInterface, error)
 	process.Searcher
 	io.Writer
 }
+
+type NetworkInterface struct {
+	Index     int
+	MTU       int
+	Name      string
+	Addresses []netip.Prefix
+}

experimental/libbox/service.go

@@ -6,11 +6,13 @@ import (
 	"syscall"
 
 	"github.com/sagernet/sing-box"
+	"github.com/sagernet/sing-box/adapter"
 	"github.com/sagernet/sing-box/common/process"
 	"github.com/sagernet/sing-box/experimental/libbox/internal/procfs"
 	"github.com/sagernet/sing-box/experimental/libbox/platform"
 	"github.com/sagernet/sing-box/option"
 	"github.com/sagernet/sing-tun"
+	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/control"
 	E "github.com/sagernet/sing/common/exceptions"
 	N "github.com/sagernet/sing/common/network"
@@ -31,7 +33,7 @@ func NewService(configContent string, platformInterface PlatformInterface) (*Box
 	instance, err := box.New(box.Options{
 		Context:           ctx,
 		Options:           options,
-		PlatformInterface: &platformInterfaceWrapper{platformInterface, platformInterface.UseProcFS()},
+		PlatformInterface: &platformInterfaceWrapper{iif: platformInterface, useProcFS: platformInterface.UseProcFS()},
 	})
 	if err != nil {
 		cancel()
@@ -58,6 +60,12 @@ var _ platform.Interface = (*platformInterfaceWrapper)(nil)
 type platformInterfaceWrapper struct {
 	iif       PlatformInterface
 	useProcFS bool
+	router    adapter.Router
+}
+
+func (w *platformInterfaceWrapper) Initialize(ctx context.Context, router adapter.Router) error {
+	w.router = router
+	return nil
 }
 
 func (w *platformInterfaceWrapper) AutoDetectInterfaceControl() control.Func {
@@ -122,3 +130,36 @@ func (w *platformInterfaceWrapper) FindProcessInfo(ctx context.Context, network
 	packageName, _ := w.iif.PackageNameByUid(uid)
 	return &process.Info{UserId: uid, PackageName: packageName}, nil
 }
+
+func (w *platformInterfaceWrapper) UsePlatformDefaultInterfaceMonitor() bool {
+	return w.iif.UsePlatformDefaultInterfaceMonitor()
+}
+
+func (w *platformInterfaceWrapper) CreateDefaultInterfaceMonitor(errorHandler E.Handler) tun.DefaultInterfaceMonitor {
+	return &platformDefaultInterfaceMonitor{
+		platformInterfaceWrapper: w,
+		errorHandler:             errorHandler,
+		defaultInterfaceIndex:    -1,
+	}
+}
+
+func (w *platformInterfaceWrapper) UsePlatformInterfaceGetter() bool {
+	return w.iif.UsePlatformInterfaceGetter()
+}
+
+func (w *platformInterfaceWrapper) Interfaces() ([]platform.NetworkInterface, error) {
+	interfaceIterator, err := w.iif.GetInterfaces()
+	if err != nil {
+		return nil, err
+	}
+	var interfaces []platform.NetworkInterface
+	for _, netInterface := range iteratorToArray[*NetworkInterface](interfaceIterator) {
+		interfaces = append(interfaces, platform.NetworkInterface{
+			Index:     int(netInterface.Index),
+			MTU:       int(netInterface.MTU),
+			Name:      netInterface.Name,
+			Addresses: common.Map(iteratorToArray[string](netInterface.Addresses), netip.MustParsePrefix),
+		})
+	}
+	return interfaces, nil
+}

route/interface_finder.go

@@ -9,7 +9,7 @@ import (
 var _ control.InterfaceFinder = (*myInterfaceFinder)(nil)
 
 type myInterfaceFinder struct {
-	ifs []net.Interface
+	interfaces []net.Interface
 }
 
 func (f *myInterfaceFinder) update() error {
@@ -17,12 +17,16 @@ func (f *myInterfaceFinder) update() error {
 	if err != nil {
 		return err
 	}
-	f.ifs = ifs
+	f.interfaces = ifs
 	return nil
 }
 
+func (f *myInterfaceFinder) updateInterfaces(interfaces []net.Interface) {
+	f.interfaces = interfaces
+}
+
 func (f *myInterfaceFinder) InterfaceIndexByName(name string) (interfaceIndex int, err error) {
-	for _, netInterface := range f.ifs {
+	for _, netInterface := range f.interfaces {
 		if netInterface.Name == name {
 			return netInterface.Index, nil
 		}
@@ -36,7 +40,7 @@ func (f *myInterfaceFinder) InterfaceIndexByName(name string) (interfaceIndex in
 }
 
 func (f *myInterfaceFinder) InterfaceNameByIndex(index int) (interfaceName string, err error) {
-	for _, netInterface := range f.ifs {
+	for _, netInterface := range f.interfaces {
 		if netInterface.Index == index {
 			return netInterface.Name, nil
 		}

route/router.go

@@ -269,29 +269,33 @@ func NewRouter(
 	router.transportMap = transportMap
 	router.transportDomainStrategy = transportDomainStrategy
 
+	usePlatformDefaultInterfaceMonitor := platformInterface != nil && platformInterface.UsePlatformDefaultInterfaceMonitor()
 	needInterfaceMonitor := options.AutoDetectInterface || common.Any(inbounds, func(inbound option.Inbound) bool {
 		return inbound.HTTPOptions.SetSystemProxy || inbound.MixedOptions.SetSystemProxy || inbound.TunOptions.AutoRoute
 	})
 
 	if needInterfaceMonitor {
-		networkMonitor, err := tun.NewNetworkUpdateMonitor(router)
+		if !usePlatformDefaultInterfaceMonitor {
-		if err == nil {
+			networkMonitor, err := tun.NewNetworkUpdateMonitor(router)
-			router.networkMonitor = networkMonitor
+			if err == nil {
-			networkMonitor.RegisterCallback(router.interfaceFinder.update)
+				router.networkMonitor = networkMonitor
+				networkMonitor.RegisterCallback(router.interfaceFinder.update)
+			}
+			interfaceMonitor, err := tun.NewDefaultInterfaceMonitor(router.networkMonitor, tun.DefaultInterfaceMonitorOptions{
+				OverrideAndroidVPN: options.OverrideAndroidVPN,
+			})
+			if err != nil {
+				return nil, E.New("auto_detect_interface unsupported on current platform")
+			}
+			interfaceMonitor.RegisterCallback(router.notifyNetworkUpdate)
+			router.interfaceMonitor = interfaceMonitor
+		} else {
+			interfaceMonitor := platformInterface.CreateDefaultInterfaceMonitor(router)
+			interfaceMonitor.RegisterCallback(router.notifyNetworkUpdate)
+			router.interfaceMonitor = interfaceMonitor
 		}
 	}
 
-	if router.networkMonitor != nil && needInterfaceMonitor {
-		interfaceMonitor, err := tun.NewDefaultInterfaceMonitor(router.networkMonitor, tun.DefaultInterfaceMonitorOptions{
-			OverrideAndroidVPN: options.OverrideAndroidVPN,
-		})
-		if err != nil {
-			return nil, E.New("auto_detect_interface unsupported on current platform")
-		}
-		interfaceMonitor.RegisterCallback(router.notifyNetworkUpdate)
-		router.interfaceMonitor = interfaceMonitor
-	}
-
 	needFindProcess := hasRule(options.Rules, isProcessRule) || hasDNSRule(dnsOptions.Rules, isProcessDNSRule) || options.FindProcess
 	needPackageManager := C.IsAndroid && platformInterface == nil && (needFindProcess || common.Any(inbounds, func(inbound option.Inbound) bool {
 		return len(inbound.TunOptions.IncludePackage) > 0 || len(inbound.TunOptions.ExcludePackage) > 0
@@ -824,6 +828,25 @@ func (r *Router) InterfaceFinder() control.InterfaceFinder {
 	return &r.interfaceFinder
 }
 
+func (r *Router) UpdateInterfaces() error {
+	if r.platformInterface == nil || !r.platformInterface.UsePlatformInterfaceGetter() {
+		return r.interfaceFinder.update()
+	} else {
+		interfaces, err := r.platformInterface.Interfaces()
+		if err != nil {
+			return err
+		}
+		r.interfaceFinder.updateInterfaces(common.Map(interfaces, func(it platform.NetworkInterface) net.Interface {
+			return net.Interface{
+				Name:  it.Name,
+				Index: it.Index,
+				MTU:   it.MTU,
+			}
+		}))
+		return nil
+	}
+}
+
 func (r *Router) AutoDetectInterface() bool {
 	return r.autoDetectInterface
 }
@@ -1137,7 +1160,7 @@ func (r *Router) NewError(ctx context.Context, err error) {
 }
 
 func (r *Router) notifyNetworkUpdate(int) error {
-	if C.IsAndroid {
+	if C.IsAndroid && r.platformInterface == nil {
 		var vpnStatus string
 		if r.interfaceMonitor.AndroidVPNEnabled() {
 			vpnStatus = "enabled"
@@ -1149,6 +1172,10 @@ func (r *Router) notifyNetworkUpdate(int) error {
 		r.logger.Info("updated default interface ", r.interfaceMonitor.DefaultInterfaceName(netip.IPv4Unspecified()), ", index ", r.interfaceMonitor.DefaultInterfaceIndex(netip.IPv4Unspecified()))
 	}
 
+	if conntrack.Enabled {
+		conntrack.Close()
+	}
+
 	for _, outbound := range r.outbounds {
 		listener, isListener := outbound.(adapter.InterfaceUpdateListener)
 		if isListener {
@@ -1158,9 +1185,5 @@ func (r *Router) notifyNetworkUpdate(int) error {
 			}
 		}
 	}
-
-	if conntrack.Enabled {
-		conntrack.Close()
-	}
 	return nil
 }

transport/dhcp/server.go

@@ -119,7 +119,7 @@ func (t *Transport) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg,
 func (t *Transport) fetchInterface() (*net.Interface, error) {
 	interfaceName := t.interfaceName
 	if t.autoInterface {
-		if t.router.NetworkMonitor() == nil {
+		if t.router.InterfaceMonitor() == nil {
 			return nil, E.New("missing monitor for auto DHCP, set route.auto_detect_interface")
 		}
 		interfaceName = t.router.InterfaceMonitor().DefaultInterfaceName(netip.Addr{})