Fix utp sniffer

Bumps [actions/setup-go](https://github.com/actions/setup-go) from 6 to 7.
- [Release notes](https://github.com/actions/setup-go/releases)
- [Commits](https://github.com/actions/setup-go/compare/v6...v7)

---
updated-dependencies:
- dependency-name: actions/setup-go
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/release-win7.yml

@@ -92,7 +92,7 @@ jobs:
           echo "ASSET_NAME=$_NAME" >> $GITHUB_ENV
 
       - name: Set up Go
-        uses: actions/setup-go@v6
+        uses: actions/setup-go@v7
         with:
           go-version-file: go.mod
           check-latest: true

.github/workflows/release.yml

@@ -193,7 +193,7 @@ jobs:
           echo "ASSET_NAME=$_NAME" >> $GITHUB_ENV
 
       - name: Set up Go
-        uses: actions/setup-go@v6
+        uses: actions/setup-go@v7
         with:
           go-version-file: go.mod
           check-latest: true

.github/workflows/test.yml

@@ -61,7 +61,7 @@ jobs:
       - name: Checkout codebase
         uses: actions/checkout@v7
       - name: Set up Go
-        uses: actions/setup-go@v6
+        uses: actions/setup-go@v7
         with:
           go-version-file: go.mod
           check-latest: true
@@ -85,7 +85,7 @@ jobs:
       - name: Checkout codebase
         uses: actions/checkout@v7
       - name: Set up Go
-        uses: actions/setup-go@v6
+        uses: actions/setup-go@v7
         with:
           go-version-file: go.mod
           check-latest: true

common/protocol/bittorrent/bittorrent.go

@@ -3,11 +3,8 @@ package bittorrent
 import (
 	"encoding/binary"
 	"errors"
-	"math"
-	"time"
 
 	"github.com/xtls/xray-core/common"
-	"github.com/xtls/xray-core/common/buf"
 )
 
 type SniffHeader struct{}
@@ -39,50 +36,44 @@ func SniffUTP(b []byte) (*SniffHeader, error) {
 		return nil, common.ErrNoClue
 	}
 
-	buffer := buf.FromBytes(b)
-
-	var typeAndVersion uint8
-
-	if binary.Read(buffer, binary.BigEndian, &typeAndVersion) != nil {
-		return nil, common.ErrNoClue
-	} else if b[0]>>4&0xF > 4 || b[0]&0xF != 1 {
+	// type 4 (ST_SYN), version 1
+	if b[0] != 0x41 {
 		return nil, errNotBittorrent
 	}
 
-	var extension uint8
-
-	if binary.Read(buffer, binary.BigEndian, &extension) != nil {
-		return nil, common.ErrNoClue
-	} else if extension != 0 && extension != 1 {
+	// timestamp_difference is always 0 in new connections
+	if binary.BigEndian.Uint32(b[8:12]) != 0 {
 		return nil, errNotBittorrent
 	}
 
+	// Walk the extension chain. Selective ack (1) and extension bits (2)
+	extension, offset := b[1], 20
 	for extension != 0 {
-		if extension != 1 {
+		if len(b) < offset+2 {
 			return nil, errNotBittorrent
 		}
-		if binary.Read(buffer, binary.BigEndian, &extension) != nil {
-			return nil, common.ErrNoClue
+		length := int(b[offset+1])
+		switch extension {
+		case 1: // selective ack
+			if length < 4 || length%4 != 0 {
+				return nil, errNotBittorrent
+			}
+		case 2: // extension bits: fixed 8 bytes, sent in ST_SYN by µTorrent
+			if length != 8 {
+				return nil, errNotBittorrent
+			}
+		default:
+			return nil, errNotBittorrent
 		}
-
-		var length uint8
-		if err := binary.Read(buffer, binary.BigEndian, &length); err != nil {
-			return nil, common.ErrNoClue
-		}
-		if common.Error2(buffer.ReadBytes(int32(length))) != nil {
-			return nil, common.ErrNoClue
+		if len(b) < offset+2+length {
+			return nil, errNotBittorrent
 		}
+		extension = b[offset]
+		offset += 2 + length
 	}
 
-	if common.Error2(buffer.ReadBytes(2)) != nil {
-		return nil, common.ErrNoClue
-	}
-
-	var timestamp uint32
-	if err := binary.Read(buffer, binary.BigEndian, &timestamp); err != nil {
-		return nil, common.ErrNoClue
-	}
-	if math.Abs(float64(time.Now().UnixMicro()-int64(timestamp))) > float64(24*time.Hour) {
+	// extensions should consume all ST_SYN payload
+	if len(b) != offset {
 		return nil, errNotBittorrent
 	}
 

common/protocol/bittorrent/bittorrent_test.go

@@ -0,0 +1,67 @@
+package bittorrent
+
+import (
+	"encoding/binary"
+	"testing"
+
+	"github.com/xtls/xray-core/common"
+)
+
+// utpPacket builds the fixed 20-byte header defined by BEP 29.
+func utpPacket(packetType, extension byte, tsDiff uint32, payload ...byte) []byte {
+	b := make([]byte, 20)
+	b[0] = packetType<<4 | 1
+	b[1] = extension
+	binary.BigEndian.PutUint16(b[2:4], 0x4a3f)     // connection_id, random
+	binary.BigEndian.PutUint32(b[4:8], 0x8c3a91d2) // timestamp_microseconds, sender's clock
+	binary.BigEndian.PutUint32(b[8:12], tsDiff)
+	binary.BigEndian.PutUint32(b[12:16], 0x00100000) // wnd_size
+	binary.BigEndian.PutUint16(b[16:18], 0x71ee)     // seq_nr, random in libutp/libtorrent
+	binary.BigEndian.PutUint16(b[18:20], 0x0000)     // ack_nr
+	return append(b, payload...)
+}
+
+func TestSniffUTP(t *testing.T) {
+	selectiveAck := []byte{0, 4, 0xff, 0x00, 0xff, 0x00}
+	wrongVersion := utpPacket(4, 0, 0)
+	wrongVersion[0] = 4<<4 | 2
+
+	cases := []struct {
+		name    string
+		payload []byte
+		err     error
+	}{
+		{"syn", utpPacket(4, 0, 0), nil},
+		{"syn with selective ack", append(utpPacket(4, 1, 0), selectiveAck...), nil},
+		{"syn with extension bits", append(utpPacket(4, 2, 0), 0, 8, 1, 2, 3, 4, 5, 6, 7, 8), nil},
+		{"extension bits with wrong length", append(utpPacket(4, 2, 0), 0, 4, 1, 2, 3, 4), errNotBittorrent},
+		{"syn with nonzero timestamp_difference", utpPacket(4, 0, 0x1234), errNotBittorrent},
+		{"syn with trailing payload", utpPacket(4, 0, 0, 'x'), errNotBittorrent},
+		// txid 0x4100, no EDNS0: the worst case colliding with the uTP header
+		{"dns query", []byte{
+			0x41, 0x00, 0x01, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			0x01, 'a', 0x02, 'c', 'o', 0x00, 0x00, 0x01, 0x00, 0x01,
+		}, errNotBittorrent},
+		{"established connection packets", utpPacket(0, 0, 0x5678, 'x', 'y', 'z'), errNotBittorrent},
+		{"state", utpPacket(2, 0, 0x5678), errNotBittorrent},
+		{"fin", utpPacket(1, 0, 0x5678), errNotBittorrent},
+		{"wrong version", wrongVersion, errNotBittorrent},
+		{"unknown packet type", utpPacket(5, 0, 0), errNotBittorrent},
+		{"unknown extension", utpPacket(4, 2, 0), errNotBittorrent},
+		{"extension chain past the datagram", utpPacket(4, 1, 0, 0, 8, 0xff), errNotBittorrent},
+		{"selective ack not in multiples of 4", append(utpPacket(4, 1, 0), 0, 3, 0xff, 0x00, 0xff), errNotBittorrent},
+		{"shorter than the header", utpPacket(4, 0, 0)[:19], common.ErrNoClue},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			h, err := SniffUTP(c.payload)
+			if err != c.err {
+				t.Fatalf("expected error %v, got %v", c.err, err)
+			}
+			if err == nil && h == nil {
+				t.Fatal("expected a sniff header, got nil")
+			}
+		})
+	}
+}

go.mod

@@ -31,7 +31,7 @@ require (
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2
 	golang.zx2c4.com/wireguard v0.0.0-20250521234502-f333402bd9cb
 	golang.zx2c4.com/wireguard/windows v1.0.1
-	google.golang.org/grpc v1.82.0
+	google.golang.org/grpc v1.82.1
 	google.golang.org/protobuf v1.36.11
 	gvisor.dev/gvisor v0.0.0-20260122175437-89a5d21be8f0
 	h12.io/socks v1.0.3

go.sum

@@ -149,8 +149,8 @@ gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
 gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478 h1:RmoJA1ujG+/lRGNfUnOMfhCy5EipVMyvUE+KNbPbTlw=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
-google.golang.org/grpc v1.82.0 h1:vguDnZUPjE26w09A63VoxZPnvPjB5Riyc0mkXPFmAIU=
-google.golang.org/grpc v1.82.0/go.mod h1:yzTZ1TB1Z3SG+LIYaI+WiE8D5+PZ3ArnrSp8zF3+/ZA=
+google.golang.org/grpc v1.82.1 h1:NnAxzGRA0677vCa4BUkOAnO5+FfQqVl9iUXeD0IqcGE=
+google.golang.org/grpc v1.82.1/go.mod h1:yzTZ1TB1Z3SG+LIYaI+WiE8D5+PZ3ArnrSp8zF3+/ZA=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
 google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

infra/conf/transport_security.go

@@ -113,8 +113,10 @@ func (c *REALITYConfig) Build() (proto.Message, error) {
 					config.MinClientVer[i] = byte(u)
 				}
 			}
+			errors.LogWarning(context.Background(), `REALITY: Changing "minClientVer" will increase the likelihood of your server's IP being blocked by the GFW`)
 		} else {
-			config.MinClientVer = []byte{26, 3, 27} // change it at your own risk: https://github.com/XTLS/Xray-core/pull/6181#issuecomment-4567373533
+			config.MinClientVer = []byte{26, 3, 27} // change it at your own risk: https://github.com/XTLS/Xray-core/commit/af7eb68028732a8ee3c0e5d6ab2b8a657bb2e770
+			errors.LogWarning(context.Background(), `REALITY: The default minimal client version is Xray-core v26.3.27, other clients may be refused to connect`)
 		}
 		if c.MaxClientVer != "" {
 			config.MaxClientVer = make([]byte, 3)
@@ -159,8 +161,10 @@ func (c *REALITYConfig) Build() (proto.Message, error) {
 		}
 
 		for _, sn := range config.ServerNames {
-			if strings.Contains(sn, "apple") || strings.Contains(sn, "icloud") {
-				errors.LogWarning(context.Background(), `REALITY: Choosing apple, icloud, etc. as the target may get your IP blocked by the GFW`)
+			sn = strings.ToLower(sn)
+			if strings.HasSuffix(sn, ".ru") || strings.HasSuffix(sn, ".ir") || strings.HasSuffix(sn, ".cn") ||
+				strings.Contains(sn, "apple") || strings.Contains(sn, "icloud") || strings.Contains(sn, "microsoft") {
+				errors.LogWarning(context.Background(), `REALITY: Choosing "`, sn, `" as the target will increase the likelihood of your server's IP being blocked by the GFW`)
 			}
 		}
 

infra/conf/tun.go

@@ -1,12 +1,19 @@
 package conf
 
 import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+	"net"
+	"strconv"
+
 	"github.com/xtls/xray-core/proxy/tun"
 	"google.golang.org/protobuf/proto"
 )
 
 type TunConfig struct {
 	Name                   string   `json:"name"`
+	Desc                   string   `json:"desc"`
 	MTU                    uint32   `json:"mtu"`
 	Gateway                []string `json:"gateway"`
 	DNS                    []string `json:"dns"`
@@ -18,6 +25,7 @@ type TunConfig struct {
 func (v *TunConfig) Build() (proto.Message, error) {
 	config := &tun.Config{
 		Name:                   v.Name,
+		Desc:                   v.Desc,
 		MTU:                    v.MTU,
 		Gateway:                v.Gateway,
 		DNS:                    v.DNS,
@@ -32,10 +40,71 @@ func (v *TunConfig) Build() (proto.Message, error) {
 	}
 
 	if config.Name == "" {
-		config.Name = "xray0"
+		name, err := GetAvailableTunName()
+		if err != nil {
+			return nil, err
+		}
+		config.Name = name
+	}
+	if config.Desc == "" {
+		config.Desc = "Wintun"
 	}
 	if config.MTU == 0 {
 		config.MTU = 1500
 	}
 	return config, nil
 }
+
+const (
+	tunNamePrefix = "utun"
+	minTunIndex   = 10
+	maxTunIndex   = 1024
+)
+
+func GetAvailableTunName() (string, error) {
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		return "", fmt.Errorf("fail to get system interface information: %w", err)
+	}
+
+	usedNames := make(map[string]struct{}, len(interfaces))
+	for _, iface := range interfaces {
+		usedNames[iface.Name] = struct{}{}
+	}
+
+	startIndex, err := randomInt(minTunIndex, maxTunIndex)
+	if err != nil {
+		return "", fmt.Errorf("fail to generate valid tun name: %w", err)
+	}
+
+	rangeSize := maxTunIndex - minTunIndex + 1
+
+	for offset := 0; offset < rangeSize; offset++ {
+		index := minTunIndex + (startIndex-minTunIndex+offset)%rangeSize
+		name := tunNamePrefix + strconv.Itoa(index)
+
+		if _, exists := usedNames[name]; !exists {
+			return name, nil
+		}
+	}
+
+	return "", fmt.Errorf(
+		"no available TUN interface name in range %s%d-%s%d",
+		tunNamePrefix,
+		minTunIndex,
+		tunNamePrefix,
+		maxTunIndex,
+	)
+}
+
+func randomInt(min, max int) (int, error) {
+	value, err := rand.Int(
+		rand.Reader,
+		big.NewInt(int64(max-min+1)),
+	)
+	if err != nil {
+		return 0, err
+	}
+
+	return min + int(value.Int64()), nil
+}

infra/conf/xray.go

@@ -176,7 +176,7 @@ func (c *InboundDetourConfig) Build() (*core.InboundHandlerConfig, error) {
 		receiverSettings.StreamSettings = ss
 		if strings.Contains(ss.SecurityType, "reality") && (receiverSettings.PortList == nil ||
 			len(receiverSettings.PortList.Ports()) != 1 || receiverSettings.PortList.Ports()[0] != 443) {
-			errors.LogWarning(context.Background(), `REALITY: Listening on non-443 ports may get your IP blocked by the GFW`)
+			errors.LogWarning(context.Background(), `REALITY: Listening on non-443 ports will increase the likelihood of your server's IP being blocked by the GFW`)
 		}
 	}
 	if c.SniffingConfig != nil {

proxy/tun/README.md

@@ -31,13 +31,17 @@ Here is simple Xray config snippet to enable the inbound:
       "port": 0,
       "protocol": "tun",
       "settings": {
-        "name": "xray0",
-        "MTU": 1492
+        "name": "utun10",
+        "desc": "Wintun",
+        "mtu": 1500
       }
     }
   ],
 ```
 
+`desc` sets the Windows Wintun adapter tunnel type and defaults to `Wintun`.
+It is ignored on other platforms.
+
 ## SUPPORTED FEATURES
 
 - IPv4 and IPv6

proxy/tun/config.pb.go

@@ -7,11 +7,12 @@
 package tun
 
 import (
-	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
-	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
 	reflect "reflect"
 	sync "sync"
 	unsafe "unsafe"
+
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
 )
 
 const (
@@ -30,6 +31,7 @@ type Config struct {
 	UserLevel              uint32                 `protobuf:"varint,5,opt,name=user_level,json=userLevel,proto3" json:"user_level,omitempty"`
 	AutoSystemRoutingTable []string               `protobuf:"bytes,6,rep,name=auto_system_routing_table,json=autoSystemRoutingTable,proto3" json:"auto_system_routing_table,omitempty"`
 	AutoOutboundsInterface string                 `protobuf:"bytes,7,opt,name=auto_outbounds_interface,json=autoOutboundsInterface,proto3" json:"auto_outbounds_interface,omitempty"`
+	Desc                   string                 `protobuf:"bytes,8,opt,name=desc,proto3" json:"desc,omitempty"`
 	unknownFields          protoimpl.UnknownFields
 	sizeCache              protoimpl.SizeCache
 }
@@ -113,11 +115,18 @@ func (x *Config) GetAutoOutboundsInterface() string {
 	return ""
 }
 
+func (x *Config) GetDesc() string {
+	if x != nil {
+		return x.Desc
+	}
+	return ""
+}
+
 var File_proxy_tun_config_proto protoreflect.FileDescriptor
 
 const file_proxy_tun_config_proto_rawDesc = "" +
 	"\n" +
-	"\x16proxy/tun/config.proto\x12\x0exray.proxy.tun\"\xee\x01\n" +
+	"\x16proxy/tun/config.proto\x12\x0exray.proxy.tun\"\x82\x02\n" +
 	"\x06Config\x12\x12\n" +
 	"\x04name\x18\x01 \x01(\tR\x04name\x12\x10\n" +
 	"\x03MTU\x18\x02 \x01(\rR\x03MTU\x12\x18\n" +
@@ -126,7 +135,8 @@ const file_proxy_tun_config_proto_rawDesc = "" +
 	"\n" +
 	"user_level\x18\x05 \x01(\rR\tuserLevel\x129\n" +
 	"\x19auto_system_routing_table\x18\x06 \x03(\tR\x16autoSystemRoutingTable\x128\n" +
-	"\x18auto_outbounds_interface\x18\a \x01(\tR\x16autoOutboundsInterfaceBL\n" +
+	"\x18auto_outbounds_interface\x18\a \x01(\tR\x16autoOutboundsInterface\x12\x12\n" +
+	"\x04desc\x18\b \x01(\tR\x04descBL\n" +
 	"\x12com.xray.proxy.tunP\x01Z#github.com/xtls/xray-core/proxy/tun\xaa\x02\x0eXray.Proxy.Tunb\x06proto3"
 
 var (

proxy/tun/config.proto

@@ -14,4 +14,5 @@ message Config {
   uint32 user_level = 5;
   repeated string auto_system_routing_table = 6;
   string auto_outbounds_interface = 7;
+  string desc = 8;
 }

proxy/tun/tun_windows.go

@@ -50,7 +50,7 @@ var _ GVisorDevice = (*WindowsTun)(nil)
 // interface with the same name exist, it tried to be reused.
 func NewTun(options *Config) (Tun, error) {
 	// instantiate wintun adapter
-	adapter, err := open(options.Name)
+	adapter, err := open(options.Name, options.Desc)
 	if err != nil {
 		return nil, err
 	}
@@ -73,12 +73,12 @@ func NewTun(options *Config) (Tun, error) {
 	return tun, nil
 }
 
-func open(name string) (*wintun.Adapter, error) {
+func open(name, desc string) (*wintun.Adapter, error) {
 	// generate a deterministic GUID from the adapter name
 	id := md5.Sum([]byte(name))
 	guid := (*windows.GUID)(unsafe.Pointer(&id[0]))
 	// try to create adapter anew
-	adapter, err := wintun.CreateAdapter(name, "Xray", guid)
+	adapter, err := wintun.CreateAdapter(name, desc, guid)
 	if err == nil {
 		return adapter, nil
 	}