Add multi network dialing

common/dialer/default.go

@@ -10,66 +10,93 @@ import (
 	"github.com/sagernet/sing-box/common/conntrack"
 	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing/common/atomic"
 	"github.com/sagernet/sing/common/control"
 	E "github.com/sagernet/sing/common/exceptions"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
 )
 
-var _ WireGuardListener = (*DefaultDialer)(nil)
+var (
+	_ ParallelInterfaceDialer = (*DefaultDialer)(nil)
+	_ WireGuardListener       = (*DefaultDialer)(nil)
+)
 
 type DefaultDialer struct {
-	dialer4             tcpDialer
-	dialer6             tcpDialer
-	udpDialer4          net.Dialer
-	udpDialer6          net.Dialer
-	udpListener         net.ListenConfig
-	udpAddr4            string
-	udpAddr6            string
-	isWireGuardListener bool
+	dialer4              tcpDialer
+	dialer6              tcpDialer
+	udpDialer4           net.Dialer
+	udpDialer6           net.Dialer
+	udpListener          net.ListenConfig
+	udpAddr4             string
+	udpAddr6             string
+	isWireGuardListener  bool
+	networkManager       adapter.NetworkManager
+	networkStrategy      C.NetworkStrategy
+	networkFallbackDelay time.Duration
+	networkLastFallback  atomic.TypedValue[time.Time]
 }
 
 func NewDefault(networkManager adapter.NetworkManager, options option.DialerOptions) (*DefaultDialer, error) {
-	var dialer net.Dialer
-	var listener net.ListenConfig
+	var (
+		dialer               net.Dialer
+		listener             net.ListenConfig
+		interfaceFinder      control.InterfaceFinder
+		networkStrategy      C.NetworkStrategy
+		networkFallbackDelay time.Duration
+	)
+	if networkManager != nil {
+		interfaceFinder = networkManager.InterfaceFinder()
+	} else {
+		interfaceFinder = control.NewDefaultInterfaceFinder()
+	}
 	if options.BindInterface != "" {
-		var interfaceFinder control.InterfaceFinder
-		if networkManager != nil {
-			interfaceFinder = networkManager.InterfaceFinder()
-		} else {
-			interfaceFinder = control.NewDefaultInterfaceFinder()
-		}
 		bindFunc := control.BindToInterface(interfaceFinder, options.BindInterface, -1)
 		dialer.Control = control.Append(dialer.Control, bindFunc)
 		listener.Control = control.Append(listener.Control, bindFunc)
-	} else if networkManager != nil && networkManager.AutoDetectInterface() {
-		bindFunc := networkManager.AutoDetectInterfaceFunc()
-		dialer.Control = control.Append(dialer.Control, bindFunc)
-		listener.Control = control.Append(listener.Control, bindFunc)
-	} else if networkManager != nil && networkManager.DefaultInterface() != "" {
-		bindFunc := control.BindToInterface(networkManager.InterfaceFinder(), networkManager.DefaultInterface(), -1)
-		dialer.Control = control.Append(dialer.Control, bindFunc)
-		listener.Control = control.Append(listener.Control, bindFunc)
-	}
-	var autoRedirectOutputMark uint32
-	if networkManager != nil {
-		autoRedirectOutputMark = networkManager.AutoRedirectOutputMark()
-	}
-	if autoRedirectOutputMark > 0 {
-		dialer.Control = control.Append(dialer.Control, control.RoutingMark(autoRedirectOutputMark))
-		listener.Control = control.Append(listener.Control, control.RoutingMark(autoRedirectOutputMark))
 	}
 	if options.RoutingMark > 0 {
 		dialer.Control = control.Append(dialer.Control, control.RoutingMark(options.RoutingMark))
 		listener.Control = control.Append(listener.Control, control.RoutingMark(options.RoutingMark))
+	}
+	if networkManager != nil {
+		autoRedirectOutputMark := networkManager.AutoRedirectOutputMark()
 		if autoRedirectOutputMark > 0 {
-			return nil, E.New("`auto_redirect` with `route_[_exclude]_address_set is conflict with `routing_mark`")
+			if options.RoutingMark > 0 {
+				return nil, E.New("`routing_mark` is conflict with `tun.auto_redirect` with `tun.route_[_exclude]_address_set")
+			}
+			dialer.Control = control.Append(dialer.Control, control.RoutingMark(autoRedirectOutputMark))
+			listener.Control = control.Append(listener.Control, control.RoutingMark(autoRedirectOutputMark))
 		}
-	} else if networkManager != nil && networkManager.DefaultMark() > 0 {
-		dialer.Control = control.Append(dialer.Control, control.RoutingMark(networkManager.DefaultMark()))
-		listener.Control = control.Append(listener.Control, control.RoutingMark(networkManager.DefaultMark()))
-		if autoRedirectOutputMark > 0 {
-			return nil, E.New("`auto_redirect` with `route_[_exclude]_address_set is conflict with `default_mark`")
+	}
+	if C.NetworkStrategy(options.NetworkStrategy) != C.NetworkStrategyDefault {
+		if options.BindInterface != "" || options.Inet4BindAddress != nil || options.Inet6BindAddress != nil {
+			return nil, E.New("`network_strategy` is conflict with `bind_interface`, `inet4_bind_address` and `inet6_bind_address`")
+		}
+		networkStrategy = C.NetworkStrategy(options.NetworkStrategy)
+		networkFallbackDelay = time.Duration(options.NetworkFallbackDelay)
+		if networkManager == nil || !networkManager.AutoDetectInterface() {
+			return nil, E.New("`route.auto_detect_interface` is require by `network_strategy`")
+		}
+	}
+	if networkManager != nil && options.BindInterface == "" && options.Inet4BindAddress == nil && options.Inet6BindAddress == nil {
+		defaultOptions := networkManager.DefaultOptions()
+		if defaultOptions.DefaultInterface != "" {
+			bindFunc := control.BindToInterface(networkManager.InterfaceFinder(), defaultOptions.DefaultInterface, -1)
+			dialer.Control = control.Append(dialer.Control, bindFunc)
+			listener.Control = control.Append(listener.Control, bindFunc)
+		} else if networkManager.AutoDetectInterface() {
+			if defaultOptions.DefaultNetworkStrategy != C.NetworkStrategyDefault && C.NetworkStrategy(options.NetworkStrategy) == C.NetworkStrategyDefault {
+				networkStrategy = defaultOptions.DefaultNetworkStrategy
+				networkFallbackDelay = defaultOptions.DefaultFallbackDelay
+				bindFunc := networkManager.ProtectFunc()
+				dialer.Control = control.Append(dialer.Control, bindFunc)
+				listener.Control = control.Append(listener.Control, bindFunc)
+			} else {
+				bindFunc := networkManager.AutoDetectInterfaceFunc()
+				dialer.Control = control.Append(dialer.Control, bindFunc)
+				listener.Control = control.Append(listener.Control, bindFunc)
+			}
 		}
 	}
 	if options.ReuseAddr {
@@ -130,6 +157,9 @@ func NewDefault(networkManager adapter.NetworkManager, options option.DialerOpti
 			listener.Control = control.Append(listener.Control, controlFn)
 		}
 	}
+	if networkStrategy != C.NetworkStrategyDefault && options.TCPFastOpen {
+		return nil, E.New("`tcp_fast_open` is conflict with `network_strategy` or `route.default_network_strategy`")
+	}
 	tcpDialer4, err := newTCPDialer(dialer4, options.TCPFastOpen)
 	if err != nil {
 		return nil, err
@@ -139,14 +169,17 @@ func NewDefault(networkManager adapter.NetworkManager, options option.DialerOpti
 		return nil, err
 	}
 	return &DefaultDialer{
-		tcpDialer4,
-		tcpDialer6,
-		udpDialer4,
-		udpDialer6,
-		listener,
-		udpAddr4,
-		udpAddr6,
-		options.IsWireGuardListener,
+		dialer4:              tcpDialer4,
+		dialer6:              tcpDialer6,
+		udpDialer4:           udpDialer4,
+		udpDialer6:           udpDialer6,
+		udpListener:          listener,
+		udpAddr4:             udpAddr4,
+		udpAddr6:             udpAddr6,
+		isWireGuardListener:  options.IsWireGuardListener,
+		networkManager:       networkManager,
+		networkStrategy:      networkStrategy,
+		networkFallbackDelay: networkFallbackDelay,
 	}, nil
 }
 
@@ -154,33 +187,88 @@ func (d *DefaultDialer) DialContext(ctx context.Context, network string, address
 	if !address.IsValid() {
 		return nil, E.New("invalid address")
 	}
-	switch N.NetworkName(network) {
-	case N.NetworkUDP:
-		if !address.IsIPv6() {
-			return trackConn(d.udpDialer4.DialContext(ctx, network, address.String()))
-		} else {
-			return trackConn(d.udpDialer6.DialContext(ctx, network, address.String()))
+	if d.networkStrategy == C.NetworkStrategyDefault {
+		switch N.NetworkName(network) {
+		case N.NetworkUDP:
+			if !address.IsIPv6() {
+				return trackConn(d.udpDialer4.DialContext(ctx, network, address.String()))
+			} else {
+				return trackConn(d.udpDialer6.DialContext(ctx, network, address.String()))
+			}
+		}
+		if !address.IsIPv6() {
+			return trackConn(DialSlowContext(&d.dialer4, ctx, network, address))
+		} else {
+			return trackConn(DialSlowContext(&d.dialer6, ctx, network, address))
 		}
-	}
-	if !address.IsIPv6() {
-		return trackConn(DialSlowContext(&d.dialer4, ctx, network, address))
 	} else {
-		return trackConn(DialSlowContext(&d.dialer6, ctx, network, address))
+		return d.DialParallelInterface(ctx, network, address, d.networkStrategy, d.networkFallbackDelay)
 	}
 }
 
+func (d *DefaultDialer) DialParallelInterface(ctx context.Context, network string, address M.Socksaddr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.Conn, error) {
+	if strategy == C.NetworkStrategyDefault {
+		return d.DialContext(ctx, network, address)
+	}
+	if !d.networkManager.AutoDetectInterface() {
+		return nil, E.New("`route.auto_detect_interface` is require by `network_strategy`")
+	}
+	var dialer net.Dialer
+	if N.NetworkName(network) == N.NetworkTCP {
+		dialer = dialerFromTCPDialer(d.dialer4)
+	} else {
+		dialer = d.udpDialer4
+	}
+	fastFallback := time.Now().Sub(d.networkLastFallback.Load()) < C.TCPTimeout
+	var (
+		conn      net.Conn
+		isPrimary bool
+		err       error
+	)
+	if !fastFallback {
+		conn, isPrimary, err = d.dialParallelInterface(ctx, dialer, network, address.String(), strategy, fallbackDelay)
+	} else {
+		conn, isPrimary, err = d.dialParallelInterfaceFastFallback(ctx, dialer, network, address.String(), strategy, fallbackDelay, d.networkLastFallback.Store)
+	}
+	if err != nil {
+		return nil, err
+	}
+	if !fastFallback && !isPrimary {
+		d.networkLastFallback.Store(time.Now())
+	}
+	return trackConn(conn, nil)
+}
+
 func (d *DefaultDialer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
-	if destination.IsIPv6() {
-		return trackPacketConn(d.udpListener.ListenPacket(ctx, N.NetworkUDP, d.udpAddr6))
-	} else if destination.IsIPv4() && !destination.Addr.IsUnspecified() {
-		return trackPacketConn(d.udpListener.ListenPacket(ctx, N.NetworkUDP+"4", d.udpAddr4))
+	if d.networkStrategy == C.NetworkStrategyDefault {
+		if destination.IsIPv6() {
+			return trackPacketConn(d.udpListener.ListenPacket(ctx, N.NetworkUDP, d.udpAddr6))
+		} else if destination.IsIPv4() && !destination.Addr.IsUnspecified() {
+			return trackPacketConn(d.udpListener.ListenPacket(ctx, N.NetworkUDP+"4", d.udpAddr4))
+		} else {
+			return trackPacketConn(d.udpListener.ListenPacket(ctx, N.NetworkUDP, d.udpAddr4))
+		}
 	} else {
-		return trackPacketConn(d.udpListener.ListenPacket(ctx, N.NetworkUDP, d.udpAddr4))
+		return d.ListenSerialInterfacePacket(ctx, destination, d.networkStrategy, d.networkFallbackDelay)
 	}
 }
 
+func (d *DefaultDialer) ListenSerialInterfacePacket(ctx context.Context, destination M.Socksaddr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.PacketConn, error) {
+	if strategy == C.NetworkStrategyDefault {
+		return d.ListenPacket(ctx, destination)
+	}
+	if !d.networkManager.AutoDetectInterface() {
+		return nil, E.New("`route.auto_detect_interface` is require by `network_strategy`")
+	}
+	network := N.NetworkUDP
+	if destination.IsIPv4() && !destination.Addr.IsUnspecified() {
+		network += "4"
+	}
+	return trackPacketConn(d.listenSerialInterfacePacket(ctx, d.udpListener, network, "", strategy, fallbackDelay))
+}
+
 func (d *DefaultDialer) ListenPacketCompat(network, address string) (net.PacketConn, error) {
-	return trackPacketConn(d.udpListener.ListenPacket(context.Background(), network, address))
+	return trackPacketConn(d.listenSerialInterfacePacket(context.Background(), d.udpListener, network, address, d.networkStrategy, d.networkFallbackDelay))
 }
 
 func trackConn(conn net.Conn, err error) (net.Conn, error) {

common/dialer/default_go1.20.go

@@ -13,3 +13,7 @@ type tcpDialer = tfo.Dialer
 func newTCPDialer(dialer net.Dialer, tfoEnabled bool) (tcpDialer, error) {
 	return tfo.Dialer{Dialer: dialer, DisableTFO: !tfoEnabled}, nil
 }
+
+func dialerFromTCPDialer(dialer tcpDialer) net.Dialer {
+	return dialer.Dialer
+}

common/dialer/default_nongo1.20.go

@@ -16,3 +16,7 @@ func newTCPDialer(dialer net.Dialer, tfoEnabled bool) (tcpDialer, error) {
 	}
 	return dialer, nil
 }
+
+func dialerFromTCPDialer(dialer tcpDialer) net.Dialer {
+	return dialer
+}

common/dialer/default_parallel_interface.go

@@ -0,0 +1,241 @@
+package dialer
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing/common/control"
+	E "github.com/sagernet/sing/common/exceptions"
+	F "github.com/sagernet/sing/common/format"
+	N "github.com/sagernet/sing/common/network"
+)
+
+func (d *DefaultDialer) dialParallelInterface(ctx context.Context, dialer net.Dialer, network string, addr string, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.Conn, bool, error) {
+	primaryInterfaces, fallbackInterfaces := selectInterfaces(d.networkManager, strategy)
+	if len(primaryInterfaces)+len(fallbackInterfaces) == 0 {
+		return nil, false, E.New("no available network interface")
+	}
+	if fallbackDelay == 0 {
+		fallbackDelay = N.DefaultFallbackDelay
+	}
+	returned := make(chan struct{})
+	defer close(returned)
+	type dialResult struct {
+		net.Conn
+		error
+		primary bool
+	}
+	results := make(chan dialResult) // unbuffered
+	startRacer := func(ctx context.Context, primary bool, iif adapter.NetworkInterface) {
+		perNetDialer := dialer
+		perNetDialer.Control = control.Append(perNetDialer.Control, control.BindToInterface(nil, iif.Name, iif.Index))
+		conn, err := perNetDialer.DialContext(ctx, network, addr)
+		if err != nil {
+			select {
+			case results <- dialResult{error: E.Cause(err, "dial ", iif.Name, " (", iif.Name, ")"), primary: primary}:
+			case <-returned:
+			}
+		} else {
+			select {
+			case results <- dialResult{Conn: conn}:
+			case <-returned:
+				conn.Close()
+			}
+		}
+	}
+	primaryCtx, primaryCancel := context.WithCancel(ctx)
+	defer primaryCancel()
+	for _, iif := range primaryInterfaces {
+		go startRacer(primaryCtx, true, iif)
+	}
+	var (
+		fallbackTimer *time.Timer
+		fallbackChan  <-chan time.Time
+	)
+	if len(fallbackInterfaces) > 0 {
+		fallbackTimer = time.NewTimer(fallbackDelay)
+		defer fallbackTimer.Stop()
+		fallbackChan = fallbackTimer.C
+	}
+	var errors []error
+	for {
+		select {
+		case <-fallbackChan:
+			fallbackCtx, fallbackCancel := context.WithCancel(ctx)
+			defer fallbackCancel()
+			for _, iif := range fallbackInterfaces {
+				go startRacer(fallbackCtx, false, iif)
+			}
+		case res := <-results:
+			if res.error == nil {
+				return res.Conn, res.primary, nil
+			}
+			errors = append(errors, res.error)
+			if len(errors) == len(primaryInterfaces)+len(fallbackInterfaces) {
+				return nil, false, E.Errors(errors...)
+			}
+			if res.primary && fallbackTimer != nil && fallbackTimer.Stop() {
+				fallbackTimer.Reset(0)
+			}
+		}
+	}
+}
+
+func (d *DefaultDialer) dialParallelInterfaceFastFallback(ctx context.Context, dialer net.Dialer, network string, addr string, strategy C.NetworkStrategy, fallbackDelay time.Duration, resetFastFallback func(time.Time)) (net.Conn, bool, error) {
+	primaryInterfaces, fallbackInterfaces := selectInterfaces(d.networkManager, strategy)
+	if len(primaryInterfaces)+len(fallbackInterfaces) == 0 {
+		return nil, false, E.New("no available network interface")
+	}
+	if fallbackDelay == 0 {
+		fallbackDelay = N.DefaultFallbackDelay
+	}
+	returned := make(chan struct{})
+	defer close(returned)
+	type dialResult struct {
+		net.Conn
+		error
+		primary bool
+	}
+	startAt := time.Now()
+	results := make(chan dialResult) // unbuffered
+	startRacer := func(ctx context.Context, primary bool, iif adapter.NetworkInterface) {
+		perNetDialer := dialer
+		perNetDialer.Control = control.Append(perNetDialer.Control, control.BindToInterface(nil, iif.Name, iif.Index))
+		conn, err := perNetDialer.DialContext(ctx, network, addr)
+		if err != nil {
+			select {
+			case results <- dialResult{error: E.Cause(err, "dial ", iif.Name, " (", iif.Name, ")"), primary: primary}:
+			case <-returned:
+			}
+		} else {
+			select {
+			case results <- dialResult{Conn: conn}:
+			case <-returned:
+				if primary && time.Since(startAt) <= fallbackDelay {
+					resetFastFallback(time.Time{})
+				}
+				conn.Close()
+			}
+		}
+	}
+	for _, iif := range primaryInterfaces {
+		go startRacer(ctx, true, iif)
+	}
+	fallbackCtx, fallbackCancel := context.WithCancel(ctx)
+	defer fallbackCancel()
+	for _, iif := range fallbackInterfaces {
+		go startRacer(fallbackCtx, false, iif)
+	}
+	var errors []error
+	for {
+		select {
+		case res := <-results:
+			if res.error == nil {
+				return res.Conn, res.primary, nil
+			}
+			errors = append(errors, res.error)
+			if len(errors) == len(primaryInterfaces)+len(fallbackInterfaces) {
+				return nil, false, E.Errors(errors...)
+			}
+		}
+	}
+}
+
+func (d *DefaultDialer) listenSerialInterfacePacket(ctx context.Context, listener net.ListenConfig, network string, addr string, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.PacketConn, error) {
+	primaryInterfaces, fallbackInterfaces := selectInterfaces(d.networkManager, strategy)
+	if len(primaryInterfaces)+len(fallbackInterfaces) == 0 {
+		return nil, E.New("no available network interface")
+	}
+	if fallbackDelay == 0 {
+		fallbackDelay = N.DefaultFallbackDelay
+	}
+	var errors []error
+	for _, primaryInterface := range primaryInterfaces {
+		perNetListener := listener
+		perNetListener.Control = control.Append(perNetListener.Control, control.BindToInterface(nil, primaryInterface.Name, primaryInterface.Index))
+		conn, err := perNetListener.ListenPacket(ctx, network, addr)
+		if err == nil {
+			return conn, nil
+		}
+		errors = append(errors, E.Cause(err, "listen ", primaryInterface.Name, " (", primaryInterface.Name, ")"))
+	}
+	for _, fallbackInterface := range fallbackInterfaces {
+		perNetListener := listener
+		perNetListener.Control = control.Append(perNetListener.Control, control.BindToInterface(nil, fallbackInterface.Name, fallbackInterface.Index))
+		conn, err := perNetListener.ListenPacket(ctx, network, addr)
+		if err == nil {
+			return conn, nil
+		}
+		errors = append(errors, E.Cause(err, "listen ", fallbackInterface.Name, " (", fallbackInterface.Name, ")"))
+	}
+	return nil, E.Errors(errors...)
+}
+
+func selectInterfaces(networkManager adapter.NetworkManager, strategy C.NetworkStrategy) (primaryInterfaces []adapter.NetworkInterface, fallbackInterfaces []adapter.NetworkInterface) {
+	interfaces := networkManager.NetworkInterfaces()
+	switch strategy {
+	case C.NetworkStrategyFallback:
+		defaultIf := networkManager.InterfaceMonitor().DefaultInterface()
+		if defaultIf != nil {
+			for _, iif := range interfaces {
+				if iif.Index == defaultIf.Index {
+					primaryInterfaces = append(primaryInterfaces, iif)
+				} else {
+					fallbackInterfaces = append(fallbackInterfaces, iif)
+				}
+			}
+		} else {
+			primaryInterfaces = interfaces
+		}
+	case C.NetworkStrategyHybrid:
+		primaryInterfaces = interfaces
+	case C.NetworkStrategyWIFI:
+		for _, iif := range interfaces {
+			if iif.Type == C.InterfaceTypeWIFI {
+				primaryInterfaces = append(primaryInterfaces, iif)
+			} else {
+				fallbackInterfaces = append(fallbackInterfaces, iif)
+			}
+		}
+	case C.NetworkStrategyCellular:
+		for _, iif := range interfaces {
+			if iif.Type == C.InterfaceTypeCellular {
+				primaryInterfaces = append(primaryInterfaces, iif)
+			} else {
+				fallbackInterfaces = append(fallbackInterfaces, iif)
+			}
+		}
+	case C.NetworkStrategyEthernet:
+		for _, iif := range interfaces {
+			if iif.Type == C.InterfaceTypeEthernet {
+				primaryInterfaces = append(primaryInterfaces, iif)
+			} else {
+				fallbackInterfaces = append(fallbackInterfaces, iif)
+			}
+		}
+	case C.NetworkStrategyWIFIOnly:
+		for _, iif := range interfaces {
+			if iif.Type == C.InterfaceTypeWIFI {
+				primaryInterfaces = append(primaryInterfaces, iif)
+			}
+		}
+	case C.NetworkStrategyCellularOnly:
+		for _, iif := range interfaces {
+			if iif.Type == C.InterfaceTypeCellular {
+				primaryInterfaces = append(primaryInterfaces, iif)
+			}
+		}
+	case C.NetworkStrategyEthernetOnly:
+		for _, iif := range interfaces {
+			if iif.Type == C.InterfaceTypeEthernet {
+				primaryInterfaces = append(primaryInterfaces, iif)
+			}
+		}
+	default:
+		panic(F.ToString("unknown network strategy: ", strategy))
+	}
+	return primaryInterfaces, fallbackInterfaces
+}

common/dialer/default_parallel_network.go

@@ -0,0 +1,122 @@
+package dialer
+
+import (
+	"context"
+	"net"
+	"net/netip"
+	"time"
+
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing/common"
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+func DialSerialNetwork(ctx context.Context, dialer ParallelInterfaceDialer, network string, destination M.Socksaddr, destinationAddresses []netip.Addr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.Conn, error) {
+	if parallelDialer, isParallel := dialer.(ParallelNetworkDialer); isParallel {
+		return parallelDialer.DialParallelNetwork(ctx, network, destination, destinationAddresses, strategy, fallbackDelay)
+	}
+	var errors []error
+	for _, address := range destinationAddresses {
+		conn, err := dialer.DialParallelInterface(ctx, network, M.SocksaddrFrom(address, destination.Port), strategy, fallbackDelay)
+		if err == nil {
+			return conn, nil
+		}
+		errors = append(errors, err)
+	}
+	return nil, E.Errors(errors...)
+}
+
+func DialParallelNetwork(ctx context.Context, dialer ParallelInterfaceDialer, network string, destination M.Socksaddr, destinationAddresses []netip.Addr, preferIPv6 bool, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.Conn, error) {
+	if fallbackDelay == 0 {
+		fallbackDelay = N.DefaultFallbackDelay
+	}
+
+	returned := make(chan struct{})
+	defer close(returned)
+
+	addresses4 := common.Filter(destinationAddresses, func(address netip.Addr) bool {
+		return address.Is4() || address.Is4In6()
+	})
+	addresses6 := common.Filter(destinationAddresses, func(address netip.Addr) bool {
+		return address.Is6() && !address.Is4In6()
+	})
+	if len(addresses4) == 0 || len(addresses6) == 0 {
+		return DialSerialNetwork(ctx, dialer, network, destination, destinationAddresses, strategy, fallbackDelay)
+	}
+	var primaries, fallbacks []netip.Addr
+	if preferIPv6 {
+		primaries = addresses6
+		fallbacks = addresses4
+	} else {
+		primaries = addresses4
+		fallbacks = addresses6
+	}
+	type dialResult struct {
+		net.Conn
+		error
+		primary bool
+		done    bool
+	}
+	results := make(chan dialResult) // unbuffered
+	startRacer := func(ctx context.Context, primary bool) {
+		ras := primaries
+		if !primary {
+			ras = fallbacks
+		}
+		c, err := DialSerialNetwork(ctx, dialer, network, destination, ras, strategy, fallbackDelay)
+		select {
+		case results <- dialResult{Conn: c, error: err, primary: primary, done: true}:
+		case <-returned:
+			if c != nil {
+				c.Close()
+			}
+		}
+	}
+	var primary, fallback dialResult
+	primaryCtx, primaryCancel := context.WithCancel(ctx)
+	defer primaryCancel()
+	go startRacer(primaryCtx, true)
+	fallbackTimer := time.NewTimer(fallbackDelay)
+	defer fallbackTimer.Stop()
+	for {
+		select {
+		case <-fallbackTimer.C:
+			fallbackCtx, fallbackCancel := context.WithCancel(ctx)
+			defer fallbackCancel()
+			go startRacer(fallbackCtx, false)
+
+		case res := <-results:
+			if res.error == nil {
+				return res.Conn, nil
+			}
+			if res.primary {
+				primary = res
+			} else {
+				fallback = res
+			}
+			if primary.done && fallback.done {
+				return nil, primary.error
+			}
+			if res.primary && fallbackTimer.Stop() {
+				fallbackTimer.Reset(0)
+			}
+		}
+	}
+}
+
+func ListenSerialNetworkPacket(ctx context.Context, dialer ParallelInterfaceDialer, destination M.Socksaddr, destinationAddresses []netip.Addr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.PacketConn, netip.Addr, error) {
+	if parallelDialer, isParallel := dialer.(ParallelNetworkDialer); isParallel {
+		return parallelDialer.ListenSerialNetworkPacket(ctx, destination, destinationAddresses, strategy, fallbackDelay)
+	}
+	var errors []error
+	for _, address := range destinationAddresses {
+		conn, err := dialer.ListenSerialInterfacePacket(ctx, M.SocksaddrFrom(address, destination.Port), strategy, fallbackDelay)
+		if err == nil {
+			return conn, address, nil
+		}
+		errors = append(errors, err)
+	}
+	return nil, netip.Addr{}, E.Errors(errors...)
+}

common/dialer/dialer.go

@@ -2,12 +2,16 @@ package dialer
 
 import (
 	"context"
+	"net"
+	"net/netip"
 	"time"
 
 	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/option"
 	"github.com/sagernet/sing-dns"
 	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
 	"github.com/sagernet/sing/service"
 )
@@ -49,3 +53,35 @@ func New(ctx context.Context, options option.DialerOptions) (N.Dialer, error) {
 	}
 	return dialer, nil
 }
+
+func NewDirect(ctx context.Context, options option.DialerOptions) (ParallelInterfaceDialer, error) {
+	if options.Detour != "" {
+		return nil, E.New("`detour` is not supported in direct context")
+	}
+	networkManager := service.FromContext[adapter.NetworkManager](ctx)
+	if options.IsWireGuardListener {
+		return NewDefault(networkManager, options)
+	}
+	dialer, err := NewDefault(networkManager, options)
+	if err != nil {
+		return nil, err
+	}
+	return NewResolveParallelInterfaceDialer(
+		service.FromContext[adapter.Router](ctx),
+		dialer,
+		true,
+		dns.DomainStrategy(options.DomainStrategy),
+		time.Duration(options.FallbackDelay),
+	), nil
+}
+
+type ParallelInterfaceDialer interface {
+	N.Dialer
+	DialParallelInterface(ctx context.Context, network string, destination M.Socksaddr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.Conn, error)
+	ListenSerialInterfacePacket(ctx context.Context, destination M.Socksaddr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.PacketConn, error)
+}
+
+type ParallelNetworkDialer interface {
+	DialParallelNetwork(ctx context.Context, network string, destination M.Socksaddr, destinationAddresses []netip.Addr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.Conn, error)
+	ListenSerialNetworkPacket(ctx context.Context, destination M.Socksaddr, destinationAddresses []netip.Addr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.PacketConn, netip.Addr, error)
+}

common/dialer/resolve.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/log"
 	"github.com/sagernet/sing-dns"
 	"github.com/sagernet/sing/common/bufio"
@@ -14,7 +15,12 @@ import (
 	N "github.com/sagernet/sing/common/network"
 )
 
-type ResolveDialer struct {
+var (
+	_ N.Dialer                = (*resolveDialer)(nil)
+	_ ParallelInterfaceDialer = (*resolveParallelNetworkDialer)(nil)
+)
+
+type resolveDialer struct {
 	dialer        N.Dialer
 	parallel      bool
 	router        adapter.Router
@@ -22,8 +28,8 @@ type ResolveDialer struct {
 	fallbackDelay time.Duration
 }
 
-func NewResolveDialer(router adapter.Router, dialer N.Dialer, parallel bool, strategy dns.DomainStrategy, fallbackDelay time.Duration) *ResolveDialer {
-	return &ResolveDialer{
+func NewResolveDialer(router adapter.Router, dialer N.Dialer, parallel bool, strategy dns.DomainStrategy, fallbackDelay time.Duration) N.Dialer {
+	return &resolveDialer{
 		dialer,
 		parallel,
 		router,
@@ -32,7 +38,25 @@ func NewResolveDialer(router adapter.Router, dialer N.Dialer, parallel bool, str
 	}
 }
 
-func (d *ResolveDialer) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+type resolveParallelNetworkDialer struct {
+	resolveDialer
+	dialer ParallelInterfaceDialer
+}
+
+func NewResolveParallelInterfaceDialer(router adapter.Router, dialer ParallelInterfaceDialer, parallel bool, strategy dns.DomainStrategy, fallbackDelay time.Duration) ParallelInterfaceDialer {
+	return &resolveParallelNetworkDialer{
+		resolveDialer{
+			dialer,
+			parallel,
+			router,
+			strategy,
+			fallbackDelay,
+		},
+		dialer,
+	}
+}
+
+func (d *resolveDialer) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
 	if !destination.IsFqdn() {
 		return d.dialer.DialContext(ctx, network, destination)
 	}
@@ -57,7 +81,7 @@ func (d *ResolveDialer) DialContext(ctx context.Context, network string, destina
 	}
 }
 
-func (d *ResolveDialer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
+func (d *resolveDialer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
 	if !destination.IsFqdn() {
 		return d.dialer.ListenPacket(ctx, destination)
 	}
@@ -82,6 +106,59 @@ func (d *ResolveDialer) ListenPacket(ctx context.Context, destination M.Socksadd
 	return bufio.NewNATPacketConn(bufio.NewPacketConn(conn), M.SocksaddrFrom(destinationAddress, destination.Port), destination), nil
 }
 
-func (d *ResolveDialer) Upstream() any {
+func (d *resolveParallelNetworkDialer) DialParallelInterface(ctx context.Context, network string, destination M.Socksaddr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.Conn, error) {
+	if !destination.IsFqdn() {
+		return d.dialer.DialContext(ctx, network, destination)
+	}
+	ctx, metadata := adapter.ExtendContext(ctx)
+	ctx = log.ContextWithOverrideLevel(ctx, log.LevelDebug)
+	metadata.Destination = destination
+	metadata.Domain = ""
+	var addresses []netip.Addr
+	var err error
+	if d.strategy == dns.DomainStrategyAsIS {
+		addresses, err = d.router.LookupDefault(ctx, destination.Fqdn)
+	} else {
+		addresses, err = d.router.Lookup(ctx, destination.Fqdn, d.strategy)
+	}
+	if err != nil {
+		return nil, err
+	}
+	if fallbackDelay == 0 {
+		fallbackDelay = d.fallbackDelay
+	}
+	if d.parallel {
+		return DialParallelNetwork(ctx, d.dialer, network, destination, addresses, d.strategy == dns.DomainStrategyPreferIPv6, strategy, fallbackDelay)
+	} else {
+		return DialSerialNetwork(ctx, d.dialer, network, destination, addresses, strategy, fallbackDelay)
+	}
+}
+
+func (d *resolveParallelNetworkDialer) ListenSerialInterfacePacket(ctx context.Context, destination M.Socksaddr, strategy C.NetworkStrategy, fallbackDelay time.Duration) (net.PacketConn, error) {
+	if !destination.IsFqdn() {
+		return d.dialer.ListenPacket(ctx, destination)
+	}
+	ctx, metadata := adapter.ExtendContext(ctx)
+	ctx = log.ContextWithOverrideLevel(ctx, log.LevelDebug)
+	metadata.Destination = destination
+	metadata.Domain = ""
+	var addresses []netip.Addr
+	var err error
+	if d.strategy == dns.DomainStrategyAsIS {
+		addresses, err = d.router.LookupDefault(ctx, destination.Fqdn)
+	} else {
+		addresses, err = d.router.Lookup(ctx, destination.Fqdn, d.strategy)
+	}
+	if err != nil {
+		return nil, err
+	}
+	conn, destinationAddress, err := ListenSerialNetworkPacket(ctx, d.dialer, destination, addresses, strategy, fallbackDelay)
+	if err != nil {
+		return nil, err
+	}
+	return bufio.NewNATPacketConn(bufio.NewPacketConn(conn), M.SocksaddrFrom(destinationAddress, destination.Port), destination), nil
+}
+
+func (d *resolveDialer) Upstream() any {
 	return d.dialer
 }

common/settings/proxy_darwin.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/sagernet/sing-box/adapter"
 	"github.com/sagernet/sing-tun"
+	"github.com/sagernet/sing/common/control"
 	E "github.com/sagernet/sing/common/exceptions"
 	M "github.com/sagernet/sing/common/metadata"
 	"github.com/sagernet/sing/common/shell"
@@ -33,7 +34,7 @@ func NewSystemProxy(ctx context.Context, serverAddr M.Socksaddr, supportSOCKS bo
 		serverAddr:   serverAddr,
 		supportSOCKS: supportSOCKS,
 	}
-	proxy.element = interfaceMonitor.RegisterCallback(proxy.update)
+	proxy.element = interfaceMonitor.RegisterCallback(proxy.routeUpdate)
 	return proxy, nil
 }
 
@@ -65,11 +66,8 @@ func (p *DarwinSystemProxy) Disable() error {
 	return err
 }
 
-func (p *DarwinSystemProxy) update(event int) {
-	if event&tun.EventInterfaceUpdate == 0 {
-		return
-	}
-	if !p.isEnabled {
+func (p *DarwinSystemProxy) routeUpdate(defaultInterface *control.Interface, flags int) {
+	if !p.isEnabled || defaultInterface == nil {
 		return
 	}
 	_ = p.update0()