New feature: Happy Eyeballs (RFC 8305)

infra/conf/transport_internet.go

@@ -699,6 +699,14 @@ type CustomSockoptConfig struct {
 	Type    string `json:"type"`
 }
 
+type HappyEyeballsConfig struct {
+	Enabled          bool   `json:"enabled"`
+	PrioritizeIPv6   bool   `json:"prioritizeIPv6"`
+	TryDelayMs       uint64 `json:"tryDelayMs"`
+	Interleave       uint32 `json:"interleave"`
+	MaxConcurrentTry uint32 `json:"maxConcurrentTry"`
+}
+
 type SocketConfig struct {
 	Mark                  int32                  `json:"mark"`
 	TFO                   interface{}            `json:"tcpFastOpen"`
@@ -718,6 +726,7 @@ type SocketConfig struct {
 	TcpMptcp              bool                   `json:"tcpMptcp"`
 	CustomSockopt         []*CustomSockoptConfig `json:"customSockopt"`
 	AddressPortStrategy   string                 `json:"addressPortStrategy"`
+	HappyEyeballsSettings *HappyEyeballsConfig   `json:"happyEyeballs"`
 }
 
 // Build implements Buildable.
@@ -809,6 +818,21 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 		return nil, errors.New("unsupported address and port strategy: ", c.AddressPortStrategy)
 	}
 
+	var happyEyeballs = &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, PrioritizeIpv6: false, TryDelayMs: 250, MaxConcurrentTry: 4}
+	if c.HappyEyeballsSettings != nil {
+		happyEyeballs.Enabled = c.HappyEyeballsSettings.Enabled
+		happyEyeballs.PrioritizeIpv6 = c.HappyEyeballsSettings.PrioritizeIPv6
+		if c.HappyEyeballsSettings.Interleave > 0 {
+			happyEyeballs.Interleave = c.HappyEyeballsSettings.Interleave
+		}
+		if c.HappyEyeballsSettings.TryDelayMs > 0 {
+			happyEyeballs.TryDelayMs = c.HappyEyeballsSettings.TryDelayMs
+		}
+		if c.HappyEyeballsSettings.MaxConcurrentTry > 0 {
+			happyEyeballs.MaxConcurrentTry = c.HappyEyeballsSettings.MaxConcurrentTry
+		}
+	}
+
 	return &internet.SocketConfig{
 		Mark:                 c.Mark,
 		Tfo:                  tfo,
@@ -828,6 +852,7 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 		TcpMptcp:             c.TcpMptcp,
 		CustomSockopt:        customSockopts,
 		AddressPortStrategy:  addressPortStrategy,
+		HappyEyeballs:        happyEyeballs,
 	}, nil
 }
 

infra/conf/transport_test.go

@@ -26,6 +26,7 @@ func TestSocketConfig(t *testing.T) {
 		Tfo:            256,
 		DomainStrategy: internet.DomainStrategy_USE_IP,
 		DialerProxy:    "tag",
+		HappyEyeballs:  &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, TryDelayMs: 250, PrioritizeIpv6: false, MaxConcurrentTry: 4},
 	}
 	runMultiTestCase(t, []TestCase{
 		{
@@ -47,6 +48,7 @@ func TestSocketConfig(t *testing.T) {
 	expectedOutput = &internet.SocketConfig{
 		Mark:          0,
 		Tfo:           -1,
+		HappyEyeballs: &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, TryDelayMs: 250, PrioritizeIpv6: false, MaxConcurrentTry: 4},
 	}
 	runMultiTestCase(t, []TestCase{
 		{
@@ -65,6 +67,7 @@ func TestSocketConfig(t *testing.T) {
 	expectedOutput = &internet.SocketConfig{
 		Mark:          0,
 		Tfo:           65535,
+		HappyEyeballs: &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, TryDelayMs: 250, PrioritizeIpv6: false, MaxConcurrentTry: 4},
 	}
 	runMultiTestCase(t, []TestCase{
 		{
@@ -83,6 +86,7 @@ func TestSocketConfig(t *testing.T) {
 	expectedOutput = &internet.SocketConfig{
 		Mark:          0,
 		Tfo:           -65535,
+		HappyEyeballs: &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, TryDelayMs: 250, PrioritizeIpv6: false, MaxConcurrentTry: 4},
 	}
 	runMultiTestCase(t, []TestCase{
 		{
@@ -101,6 +105,7 @@ func TestSocketConfig(t *testing.T) {
 	expectedOutput = &internet.SocketConfig{
 		Mark:          0,
 		Tfo:           0,
+		HappyEyeballs: &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, TryDelayMs: 250, PrioritizeIpv6: false, MaxConcurrentTry: 4},
 	}
 	runMultiTestCase(t, []TestCase{
 		{
@@ -119,6 +124,7 @@ func TestSocketConfig(t *testing.T) {
 	expectedOutput = &internet.SocketConfig{
 		Mark:          0,
 		Tfo:           0,
+		HappyEyeballs: &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, TryDelayMs: 250, PrioritizeIpv6: false, MaxConcurrentTry: 4},
 	}
 	runMultiTestCase(t, []TestCase{
 		{
@@ -135,6 +141,7 @@ func TestSocketConfig(t *testing.T) {
 	expectedOutput = &internet.SocketConfig{
 		Mark:          0,
 		Tfo:           0,
+		HappyEyeballs: &internet.HappyEyeballsConfig{Enabled: false, Interleave: 1, TryDelayMs: 250, PrioritizeIpv6: false, MaxConcurrentTry: 4},
 	}
 	runMultiTestCase(t, []TestCase{
 		{

transport/internet/config.pb.go

@@ -529,6 +529,7 @@ type SocketConfig struct {
 	TcpMptcp                   bool                 `protobuf:"varint,19,opt,name=tcp_mptcp,json=tcpMptcp,proto3" json:"tcp_mptcp,omitempty"`
 	CustomSockopt              []*CustomSockopt     `protobuf:"bytes,20,rep,name=customSockopt,proto3" json:"customSockopt,omitempty"`
 	AddressPortStrategy        AddressPortStrategy  `protobuf:"varint,21,opt,name=address_port_strategy,json=addressPortStrategy,proto3,enum=xray.transport.internet.AddressPortStrategy" json:"address_port_strategy,omitempty"`
+	HappyEyeballs              *HappyEyeballsConfig `protobuf:"bytes,22,opt,name=happy_eyeballs,json=happyEyeballs,proto3" json:"happy_eyeballs,omitempty"`
 }
 
 func (x *SocketConfig) Reset() {
@@ -708,6 +709,90 @@ func (x *SocketConfig) GetAddressPortStrategy() AddressPortStrategy {
 	return AddressPortStrategy_None
 }
 
+func (x *SocketConfig) GetHappyEyeballs() *HappyEyeballsConfig {
+	if x != nil {
+		return x.HappyEyeballs
+	}
+	return nil
+}
+
+type HappyEyeballsConfig struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Enabled          bool   `protobuf:"varint,1,opt,name=enabled,proto3" json:"enabled,omitempty"`
+	PrioritizeIpv6   bool   `protobuf:"varint,2,opt,name=prioritize_ipv6,json=prioritizeIpv6,proto3" json:"prioritize_ipv6,omitempty"`
+	Interleave       uint32 `protobuf:"varint,3,opt,name=interleave,proto3" json:"interleave,omitempty"`
+	TryDelayMs       uint64 `protobuf:"varint,4,opt,name=try_delayMs,json=tryDelayMs,proto3" json:"try_delayMs,omitempty"`
+	MaxConcurrentTry uint32 `protobuf:"varint,5,opt,name=max_concurrent_try,json=maxConcurrentTry,proto3" json:"max_concurrent_try,omitempty"`
+}
+
+func (x *HappyEyeballsConfig) Reset() {
+	*x = HappyEyeballsConfig{}
+	mi := &file_transport_internet_config_proto_msgTypes[5]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *HappyEyeballsConfig) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*HappyEyeballsConfig) ProtoMessage() {}
+
+func (x *HappyEyeballsConfig) ProtoReflect() protoreflect.Message {
+	mi := &file_transport_internet_config_proto_msgTypes[5]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use HappyEyeballsConfig.ProtoReflect.Descriptor instead.
+func (*HappyEyeballsConfig) Descriptor() ([]byte, []int) {
+	return file_transport_internet_config_proto_rawDescGZIP(), []int{5}
+}
+
+func (x *HappyEyeballsConfig) GetEnabled() bool {
+	if x != nil {
+		return x.Enabled
+	}
+	return false
+}
+
+func (x *HappyEyeballsConfig) GetPrioritizeIpv6() bool {
+	if x != nil {
+		return x.PrioritizeIpv6
+	}
+	return false
+}
+
+func (x *HappyEyeballsConfig) GetInterleave() uint32 {
+	if x != nil {
+		return x.Interleave
+	}
+	return 0
+}
+
+func (x *HappyEyeballsConfig) GetTryDelayMs() uint64 {
+	if x != nil {
+		return x.TryDelayMs
+	}
+	return 0
+}
+
+func (x *HappyEyeballsConfig) GetMaxConcurrentTry() uint32 {
+	if x != nil {
+		return x.MaxConcurrentTry
+	}
+	return 0
+}
+
 var File_transport_internet_config_proto protoreflect.FileDescriptor
 
 var file_transport_internet_config_proto_rawDesc = []byte{
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@@ -827,37 +912,55 @@ var file_transport_internet_config_proto_rawDesc = []byte{
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-	0x6e, 0x65, 0x74, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
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+	0x74, 0x41, 0x6e, 0x64, 0x41, 0x64, 0x64, 0x72, 0x65, 0x73, 0x73, 0x10, 0x03, 0x12, 0x0f, 0x0a,
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+	0x10, 0x05, 0x12, 0x15, 0x0a, 0x11, 0x54, 0x78, 0x74, 0x50, 0x6f, 0x72, 0x74, 0x41, 0x6e, 0x64,
+	0x41, 0x64, 0x64, 0x72, 0x65, 0x73, 0x73, 0x10, 0x06, 0x42, 0x67, 0x0a, 0x1b, 0x63, 0x6f, 0x6d,
+	0x2e, 0x78, 0x72, 0x61, 0x79, 0x2e, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2e,
+	0x69, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x50, 0x01, 0x5a, 0x2c, 0x67, 0x69, 0x74, 0x68,
+	0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x78, 0x74, 0x6c, 0x73, 0x2f, 0x78, 0x72, 0x61, 0x79,
+	0x2d, 0x63, 0x6f, 0x72, 0x65, 0x2f, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2f,
+	0x69, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0xaa, 0x02, 0x17, 0x58, 0x72, 0x61, 0x79, 0x2e,
+	0x54, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2e, 0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e,
+	0x65, 0x74, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (
@@ -873,7 +976,7 @@ func file_transport_internet_config_proto_rawDescGZIP() []byte {
 }
 
 var file_transport_internet_config_proto_enumTypes = make([]protoimpl.EnumInfo, 3)
-var file_transport_internet_config_proto_msgTypes = make([]protoimpl.MessageInfo, 5)
+var file_transport_internet_config_proto_msgTypes = make([]protoimpl.MessageInfo, 6)
 var file_transport_internet_config_proto_goTypes = []any{
 	(DomainStrategy)(0),          // 0: xray.transport.internet.DomainStrategy
 	(AddressPortStrategy)(0),     // 1: xray.transport.internet.AddressPortStrategy
@@ -883,24 +986,26 @@ var file_transport_internet_config_proto_goTypes = []any{
 	(*ProxyConfig)(nil),          // 5: xray.transport.internet.ProxyConfig
 	(*CustomSockopt)(nil),        // 6: xray.transport.internet.CustomSockopt
 	(*SocketConfig)(nil),         // 7: xray.transport.internet.SocketConfig
-	(*serial.TypedMessage)(nil),  // 8: xray.common.serial.TypedMessage
+	(*HappyEyeballsConfig)(nil),  // 8: xray.transport.internet.HappyEyeballsConfig
-	(*net.IPOrDomain)(nil),       // 9: xray.common.net.IPOrDomain
+	(*serial.TypedMessage)(nil),  // 9: xray.common.serial.TypedMessage
+	(*net.IPOrDomain)(nil),       // 10: xray.common.net.IPOrDomain
 }
 var file_transport_internet_config_proto_depIdxs = []int32{
-	8, // 0: xray.transport.internet.TransportConfig.settings:type_name -> xray.common.serial.TypedMessage
+	9,  // 0: xray.transport.internet.TransportConfig.settings:type_name -> xray.common.serial.TypedMessage
-	9, // 1: xray.transport.internet.StreamConfig.address:type_name -> xray.common.net.IPOrDomain
+	10, // 1: xray.transport.internet.StreamConfig.address:type_name -> xray.common.net.IPOrDomain
 	3,  // 2: xray.transport.internet.StreamConfig.transport_settings:type_name -> xray.transport.internet.TransportConfig
-	8, // 3: xray.transport.internet.StreamConfig.security_settings:type_name -> xray.common.serial.TypedMessage
+	9,  // 3: xray.transport.internet.StreamConfig.security_settings:type_name -> xray.common.serial.TypedMessage
 	7,  // 4: xray.transport.internet.StreamConfig.socket_settings:type_name -> xray.transport.internet.SocketConfig
 	2,  // 5: xray.transport.internet.SocketConfig.tproxy:type_name -> xray.transport.internet.SocketConfig.TProxyMode
 	0,  // 6: xray.transport.internet.SocketConfig.domain_strategy:type_name -> xray.transport.internet.DomainStrategy
 	6,  // 7: xray.transport.internet.SocketConfig.customSockopt:type_name -> xray.transport.internet.CustomSockopt
 	1,  // 8: xray.transport.internet.SocketConfig.address_port_strategy:type_name -> xray.transport.internet.AddressPortStrategy
-	9, // [9:9] is the sub-list for method output_type
+	8,  // 9: xray.transport.internet.SocketConfig.happy_eyeballs:type_name -> xray.transport.internet.HappyEyeballsConfig
-	9, // [9:9] is the sub-list for method input_type
+	10, // [10:10] is the sub-list for method output_type
-	9, // [9:9] is the sub-list for extension type_name
+	10, // [10:10] is the sub-list for method input_type
-	9, // [9:9] is the sub-list for extension extendee
+	10, // [10:10] is the sub-list for extension type_name
-	0, // [0:9] is the sub-list for field type_name
+	10, // [10:10] is the sub-list for extension extendee
+	0,  // [0:10] is the sub-list for field type_name
 }
 
 func init() { file_transport_internet_config_proto_init() }
@@ -914,7 +1019,7 @@ func file_transport_internet_config_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_transport_internet_config_proto_rawDesc,
 			NumEnums:      3,
-			NumMessages:   5,
+			NumMessages:   6,
 			NumExtensions: 0,
 			NumServices:   0,
 		},

transport/internet/config.proto

@@ -130,4 +130,14 @@ message SocketConfig {
   repeated CustomSockopt customSockopt = 20;
 
   AddressPortStrategy address_port_strategy = 21;
+
+  HappyEyeballsConfig happy_eyeballs = 22;
+}
+
+message HappyEyeballsConfig {
+  bool enabled = 1;
+  bool prioritize_ipv6 = 2;
+  uint32 interleave = 3;
+  uint64 try_delayMs = 4;
+  uint32 max_concurrent_try = 5;
 }

transport/internet/dialer.go

@@ -255,9 +255,11 @@ func DialSystem(ctx context.Context, dest net.Destination, sockopt *SocketConfig
 			if sockopt.DomainStrategy.forceIP() {
 				return nil, err
 			}
-		} else {
+		} else if !sockopt.HappyEyeballs.Enabled || len(ips) < 2 || len(sockopt.DialerProxy) > 0 || dest.Network != net.Network_TCP {
 			dest.Address = net.IPAddress(ips[dice.Roll(len(ips))])
 			errors.LogInfo(ctx, "replace destination with "+dest.String())
+		} else {
+			return TcpRaceDial(ctx, src, ips, dest.Port, sockopt)
 		}
 	}
 

transport/internet/happy_eyeballs.go

@@ -0,0 +1,165 @@
+package internet
+
+import (
+	"context"
+	"github.com/xtls/xray-core/common/net"
+	"time"
+)
+
+type result struct {
+	err   error
+	conn  net.Conn
+	index int
+}
+
+func TcpRaceDial(ctx context.Context, src net.Address, ips []net.IP, port net.Port, sockopt *SocketConfig) (net.Conn, error) {
+	if len(ips) < 2 {
+		panic("at least 2 ips is required to race dial")
+	}
+	ips = sortIPs(ips, sockopt.HappyEyeballs.PrioritizeIpv6, sockopt.HappyEyeballs.Interleave)
+	newCtx, cancel := context.WithCancel(ctx)
+	defer cancel()
+	var resultCh = make(chan *result, len(ips))
+	nextTryIndex := 0
+	activeNum := uint32(0)
+	waitTime := time.Duration(0)
+	var winConn net.Conn
+	for {
+		select {
+		case r := <-resultCh:
+			activeNum--
+			select {
+			case <-ctx.Done():
+				cancel()
+				waitTime = 100 * time.Hour
+				if winConn != nil {
+					winConn.Close()
+				}
+				if r.conn != nil {
+					r.conn.Close()
+				}
+				if activeNum == 0 {
+					return nil, ctx.Err()
+				}
+				continue
+			default:
+				if r.conn != nil {
+					cancel()
+					waitTime = 100 * time.Hour
+					if winConn == nil {
+						winConn = r.conn
+					} else {
+						r.conn.Close()
+					}
+				}
+				if winConn != nil && activeNum == 0 {
+					return winConn, nil
+				}
+				if winConn != nil {
+					continue
+				}
+				if nextTryIndex < len(ips) {
+					waitTime = time.Duration(0)
+					continue
+				}
+				if activeNum == 0 {
+					return nil, r.err
+				}
+				waitTime = 100 * time.Hour
+				continue
+			}
+
+		case <-time.After(waitTime):
+			if nextTryIndex == len(ips) || activeNum == sockopt.HappyEyeballs.MaxConcurrentTry {
+				panic("impossible situation")
+			}
+			go tcpTryDial(newCtx, src, sockopt, ips[nextTryIndex], port, nextTryIndex, resultCh)
+			activeNum++
+			nextTryIndex++
+			if nextTryIndex == len(ips) || activeNum == sockopt.HappyEyeballs.MaxConcurrentTry {
+				waitTime = 100 * time.Hour
+			} else {
+				waitTime = time.Duration(sockopt.HappyEyeballs.TryDelayMs) * time.Millisecond
+			}
+			continue
+		}
+	}
+}
+
+// sortIPs sort IPs according to rfc 8305.
+func sortIPs(ips []net.IP, priorIPv6 bool, interleave uint32) []net.IP {
+	if len(ips) == 0 {
+		return ips
+	}
+	var ip4 = make([]net.IP, 0, len(ips))
+	var ip6 = make([]net.IP, 0, len(ips))
+	for _, ip := range ips {
+		parsedIp := net.IPAddress(ip).IP()
+		if len(parsedIp) == net.IPv4len {
+			ip4 = append(ip4, parsedIp)
+		} else {
+			ip6 = append(ip6, parsedIp)
+		}
+	}
+
+	if len(ip4) == 0 || len(ip6) == 0 {
+		return ips
+	}
+
+	var newIPs = make([]net.IP, 0, len(ips))
+	consumeIP4 := 0
+	consumeIP6 := 0
+	consumeTurn := uint32(0)
+	ip4turn := true
+	if priorIPv6 {
+		ip4turn = false
+	}
+	for {
+		if ip4turn {
+			newIPs = append(newIPs, ip4[consumeIP4])
+			consumeIP4++
+			if consumeIP4 == len(ip4) {
+				newIPs = append(newIPs, ip6[consumeIP6:]...)
+				break
+			}
+			consumeTurn++
+			if consumeTurn == interleave {
+				ip4turn = false
+				consumeTurn = uint32(0)
+			}
+		} else {
+			newIPs = append(newIPs, ip6[consumeIP6])
+			consumeIP6++
+			if consumeIP6 == len(ip6) {
+				newIPs = append(newIPs, ip4[consumeIP4:]...)
+				break
+			}
+			consumeTurn++
+			if consumeTurn == interleave {
+				ip4turn = true
+				consumeTurn = uint32(0)
+			}
+		}
+	}
+
+	return newIPs
+}
+
+func tcpTryDial(ctx context.Context, src net.Address, sockopt *SocketConfig, ip net.IP, port net.Port, index int, resultCh chan<- *result) {
+	conn, err := effectiveSystemDialer.Dial(ctx, src, net.Destination{Address: net.IPAddress(ip), Network: net.Network_TCP, Port: port}, sockopt)
+	select {
+	case <-ctx.Done():
+		if conn != nil {
+			conn.Close()
+		}
+		resultCh <- &result{err: ctx.Err(), index: index}
+		return
+	default:
+		if err != nil {
+			resultCh <- &result{err: err, index: index}
+			return
+		}
+		resultCh <- &result{conn: conn, index: index}
+		return
+	}
+}