Fix interface monitor for android

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 {
-	Next() OnDemandRule
+type InterfaceUpdateListener interface {
+	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
+}