Fix unexpected TTL clamp

app/dns/dnscommon.go

@@ -198,9 +198,14 @@ func parseResponse(payload []byte) (*IPRecord, error) {
 	ipRecord := &IPRecord{
 		ReqID:     h.ID,
 		RCode:     h.RCode,
-		Expire:    now.Add(time.Second * dns_feature.DefaultTTL),
 		RawHeader: &h,
 	}
+	defer func() {
+		// set to default TTL if no valid TTL is found
+		if ipRecord.Expire.IsZero() {
+			ipRecord.Expire = now.Add(time.Second * dns_feature.DefaultTTL)
+		}
+	}()
 
 L:
 	for {
@@ -217,7 +222,7 @@ L:
 			ttl = 1
 		}
 		expire := now.Add(time.Duration(ttl) * time.Second)
-		if ipRecord.Expire.After(expire) {
+		if ipRecord.Expire.IsZero() || ipRecord.Expire.After(expire) {
 			ipRecord.Expire = expire
 		}
 

core/core.go

@@ -20,7 +20,7 @@ import (
 var (
 	Version_x byte = 26
 	Version_y byte = 6
-	Version_z byte = 22
+	Version_z byte = 1
 )
 
 var (

go.mod

@@ -4,7 +4,7 @@ go 1.26
 
 require (
 	github.com/apernet/quic-go v0.59.1-0.20260425001925-6c6cc9bcb716
-	github.com/cloudflare/circl v1.6.4
+	github.com/cloudflare/circl v1.6.3
 	github.com/ghodss/yaml v1.0.1-0.20220118164431-d8423dcdf344
 	github.com/golang/mock v1.7.0-rc.1
 	github.com/google/go-cmp v0.7.0
@@ -12,7 +12,7 @@ require (
 	github.com/klauspost/cpuid/v2 v2.3.0
 	github.com/miekg/dns v1.1.72
 	github.com/pelletier/go-toml v1.9.5
-	github.com/pion/stun/v3 v3.1.6
+	github.com/pion/stun/v3 v3.1.5
 	github.com/pires/go-proxyproto v0.12.0
 	github.com/refraction-networking/utls v1.8.3-0.20260301010127-aa6edf4b11af
 	github.com/robfig/cron/v3 v3.0.1

go.sum

@@ -4,8 +4,8 @@ github.com/apernet/quic-go v0.59.1-0.20260425001925-6c6cc9bcb716 h1:J1O+xpLuJWkd
 github.com/apernet/quic-go v0.59.1-0.20260425001925-6c6cc9bcb716/go.mod h1:Npbg8qBtAZlsAB3FWmqwlVh5jtVG6a4DlYsOylUpvzA=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-github.com/cloudflare/circl v1.6.4 h1:pOXuDTCEYyzydgUpQ0CQz3LsinKjiSk6nNP5Lt5K64U=
-github.com/cloudflare/circl v1.6.4/go.mod h1:YxarevkLlbaHuWsxG6vmYNWBEsSp4pnp7j+4VljMavY=
+github.com/cloudflare/circl v1.6.3 h1:9GPOhQGF9MCYUeXyMYlqTR6a5gTrgR/fBLXvUgtVcg8=
+github.com/cloudflare/circl v1.6.3/go.mod h1:2eXP6Qfat4O/Yhh8BznvKnJ+uzEoTQ6jVKJRn81BiS4=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -49,8 +49,8 @@ github.com/pion/dtls/v3 v3.1.4 h1:QhvtMflMfu9Kf0RcDC5BJBle4caPskByrKQR6uuYqpY=
 github.com/pion/dtls/v3 v3.1.4/go.mod h1:cr/qotLISUw/9C1m83ZPNZtj9WnXkYLpfCptPqbkInc=
 github.com/pion/logging v0.2.4 h1:tTew+7cmQ+Mc1pTBLKH2puKsOvhm32dROumOZ655zB8=
 github.com/pion/logging v0.2.4/go.mod h1:DffhXTKYdNZU+KtJ5pyQDjvOAh/GsNSyv1lbkFbe3so=
-github.com/pion/stun/v3 v3.1.6 h1:WnhsD0eHCiwCfKNkVx0VJJwr2Y3eV4Ueih3KJ+dfZy8=
-github.com/pion/stun/v3 v3.1.6/go.mod h1:zRUghXSQU32Lx5orJsz3uYMkIihweXb3mu5gIns02fs=
+github.com/pion/stun/v3 v3.1.5 h1:Y1FHlhaI6+4UoC5i/zQf4F7JvdZtB24/05oyy/GF1x8=
+github.com/pion/stun/v3 v3.1.5/go.mod h1:zRUghXSQU32Lx5orJsz3uYMkIihweXb3mu5gIns02fs=
 github.com/pion/transport/v4 v4.0.2 h1:ifYlPqNwsy6aKQ9y8yzxXlHae5431ZrH2avkD/Rn6Tk=
 github.com/pion/transport/v4 v4.0.2/go.mod h1:06hFI+jCFcok2X2MekVufNZ/uzNZXivGBPfviSVcjgM=
 github.com/pires/go-proxyproto v0.12.0 h1:TTCxD66dU898tahivkqc3hoceZp7P44FnorWyo9d5vM=

infra/conf/transport_internet.go

@@ -1409,12 +1409,10 @@ func (c *HeaderCustomTCP) Build() (proto.Message, error) {
 }
 
 type FragmentMask struct {
-	Packets  string       `json:"packets"`
-	Length   Int32Range   `json:"length"`
-	Delay    Int32Range   `json:"delay"`
-	Lengths  []Int32Range `json:"lengths"`
-	Delays   []Int32Range `json:"delays"`
-	MaxSplit Int32Range   `json:"maxSplit"`
+	Packets  string     `json:"packets"`
+	Length   Int32Range `json:"length"`
+	Delay    Int32Range `json:"delay"`
+	MaxSplit Int32Range `json:"maxSplit"`
 }
 
 func (c *FragmentMask) Build() (proto.Message, error) {
@@ -1439,29 +1437,14 @@ func (c *FragmentMask) Build() (proto.Message, error) {
 		}
 	}
 
-	if len(c.Lengths) > 0 {
-		for _, r := range c.Lengths {
-			config.LengthsMin = append(config.LengthsMin, int64(r.From))
-			config.LengthsMax = append(config.LengthsMax, int64(r.To))
-		}
-	} else {
-		config.LengthsMin = append(config.LengthsMin, int64(c.Length.From))
-		config.LengthsMax = append(config.LengthsMax, int64(c.Length.To))
+	config.LengthMin = int64(c.Length.From)
+	config.LengthMax = int64(c.Length.To)
+	if config.LengthMin == 0 {
+		return nil, errors.New("LengthMin can't be 0")
 	}
 
-	if config.LengthsMin[len(config.LengthsMin)-1] == 0 {
-		return nil, errors.New("last lengths entry min can't be 0")
-	}
-
-	if len(c.Delays) > 0 {
-		for _, r := range c.Delays {
-			config.DelaysMin = append(config.DelaysMin, int64(r.From))
-			config.DelaysMax = append(config.DelaysMax, int64(r.To))
-		}
-	} else {
-		config.DelaysMin = append(config.DelaysMin, int64(c.Delay.From))
-		config.DelaysMax = append(config.DelaysMax, int64(c.Delay.To))
-	}
+	config.DelayMin = int64(c.Delay.From)
+	config.DelayMax = int64(c.Delay.To)
 
 	config.MaxSplitMin = int64(c.MaxSplit.From)
 	config.MaxSplitMax = int64(c.MaxSplit.To)

proxy/tun/handler.go

@@ -143,14 +143,7 @@ func (t *Handler) HandleConnection(conn net.Conn, destination net.Destination) {
 	defer cancel()
 	ctx = c.ContextWithID(ctx, session.NewID())
 
-	// if the connection is already closed, conn.RemoteAddr() will be nil
-	// due to gvisor weird behavior
-	remote := conn.RemoteAddr()
-	if remote == nil {
-		errors.LogInfo(t.ctx, "dropped quickly closed connection")
-		return
-	}
-	source := net.DestinationFromAddr(remote)
+	source := net.DestinationFromAddr(conn.RemoteAddr())
 	inbound := session.Inbound{
 		Name:          "tun",
 		Tag:           t.tag,

proxy/tun/tun_linux.go

@@ -4,11 +4,8 @@ package tun
 
 import (
 	"net"
-	"strconv"
 
 	"github.com/vishvananda/netlink"
-	"github.com/xtls/xray-core/common/errors"
-	"github.com/xtls/xray-core/common/platform"
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/tcpip/link/fdbased"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
@@ -21,7 +18,6 @@ type LinuxTun struct {
 	tunFd   int
 	tunLink netlink.Link
 	options *Config
-	ownsTun bool
 }
 
 // LinuxTun implements Tun
@@ -29,24 +25,12 @@ var _ Tun = (*LinuxTun)(nil)
 
 // NewTun builds new tun interface handler (linux specific)
 func NewTun(options *Config) (Tun, error) {
-	tunFd, tunLink, fdProvided, err := openFromEnv(options.Name)
-	if err != nil {
-		return nil, err
-	}
-	if fdProvided {
-		return &LinuxTun{
-			tunFd:   tunFd,
-			tunLink: tunLink,
-			options: options,
-		}, nil
-	}
-
-	tunFd, err = open(options.Name)
+	tunFd, err := open(options.Name)
 	if err != nil {
 		return nil, err
 	}
 
-	tunLink, err = setup(options.Name, int(options.MTU))
+	tunLink, err := setup(options.Name, int(options.MTU))
 	if err != nil {
 		_ = unix.Close(tunFd)
 		return nil, err
@@ -56,59 +40,11 @@ func NewTun(options *Config) (Tun, error) {
 		tunFd:   tunFd,
 		tunLink: tunLink,
 		options: options,
-		ownsTun: true,
 	}
 
 	return linuxTun, nil
 }
 
-func openFromEnv(expectedName string) (int, netlink.Link, bool, error) {
-	fdStr := platform.NewEnvFlag(platform.TunFdKey).GetValue(func() string { return "" })
-	if fdStr == "" {
-		return -1, nil, false, nil
-	}
-
-	fd, err := strconv.Atoi(fdStr)
-	if err != nil {
-		return -1, nil, true, errors.New("invalid ", platform.TunFdKey).Base(err)
-	}
-	if fd < 3 {
-		return -1, nil, true, errors.New("invalid ", platform.TunFdKey, ": file descriptor must be >= 3")
-	}
-
-	ifr, err := unix.NewIfreq("")
-	if err != nil {
-		return -1, nil, true, err
-	}
-	if err = unix.IoctlIfreq(fd, unix.TUNGETIFF, ifr); err != nil {
-		return -1, nil, true, err
-	}
-
-	flags := ifr.Uint16()
-	if flags&unix.IFF_TUN == 0 {
-		return -1, nil, true, errors.New("invalid ", platform.TunFdKey, ": file descriptor is not a TUN device")
-	}
-	if flags&unix.IFF_NO_PI == 0 {
-		return -1, nil, true, errors.New("invalid ", platform.TunFdKey, ": TUN device must use IFF_NO_PI")
-	}
-
-	actualName := ifr.Name()
-	if expectedName != "" && actualName != expectedName {
-		return -1, nil, true, errors.New("invalid ", platform.TunFdKey, ": TUN device name ", actualName, " does not match configured name ", expectedName)
-	}
-
-	tunLink, err := netlink.LinkByName(actualName)
-	if err != nil {
-		return -1, nil, true, err
-	}
-
-	if err = unix.SetNonblock(fd, true); err != nil {
-		return -1, nil, true, err
-	}
-
-	return fd, tunLink, true, nil
-}
-
 // open the file that implements tun interface in the OS
 func open(name string) (int, error) {
 	fd, err := unix.Open("/dev/net/tun", unix.O_RDWR, 0)
@@ -157,10 +93,6 @@ func setup(name string, MTU int) (netlink.Link, error) {
 
 // Start is called by handler to bring tun interface to life
 func (t *LinuxTun) Start() error {
-	if !t.ownsTun {
-		return nil
-	}
-
 	err := netlink.LinkSetUp(t.tunLink)
 	if err != nil {
 		return err
@@ -171,9 +103,7 @@ func (t *LinuxTun) Start() error {
 
 // Close is called to shut down the tun interface
 func (t *LinuxTun) Close() error {
-	if t.ownsTun {
-		_ = netlink.LinkSetDown(t.tunLink)
-	}
+	_ = netlink.LinkSetDown(t.tunLink)
 	_ = unix.Close(t.tunFd)
 
 	return nil

transport/internet/finalmask/fragment/config.pb.go

@@ -25,12 +25,12 @@ type Config struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	PacketsFrom   int64                  `protobuf:"varint,1,opt,name=packets_from,json=packetsFrom,proto3" json:"packets_from,omitempty"`
 	PacketsTo     int64                  `protobuf:"varint,2,opt,name=packets_to,json=packetsTo,proto3" json:"packets_to,omitempty"`
+	LengthMin     int64                  `protobuf:"varint,3,opt,name=length_min,json=lengthMin,proto3" json:"length_min,omitempty"`
+	LengthMax     int64                  `protobuf:"varint,4,opt,name=length_max,json=lengthMax,proto3" json:"length_max,omitempty"`
+	DelayMin      int64                  `protobuf:"varint,5,opt,name=delay_min,json=delayMin,proto3" json:"delay_min,omitempty"`
+	DelayMax      int64                  `protobuf:"varint,6,opt,name=delay_max,json=delayMax,proto3" json:"delay_max,omitempty"`
 	MaxSplitMin   int64                  `protobuf:"varint,7,opt,name=max_split_min,json=maxSplitMin,proto3" json:"max_split_min,omitempty"`
 	MaxSplitMax   int64                  `protobuf:"varint,8,opt,name=max_split_max,json=maxSplitMax,proto3" json:"max_split_max,omitempty"`
-	LengthsMin    []int64                `protobuf:"varint,9,rep,packed,name=lengths_min,json=lengthsMin,proto3" json:"lengths_min,omitempty"`
-	LengthsMax    []int64                `protobuf:"varint,10,rep,packed,name=lengths_max,json=lengthsMax,proto3" json:"lengths_max,omitempty"`
-	DelaysMin     []int64                `protobuf:"varint,11,rep,packed,name=delays_min,json=delaysMin,proto3" json:"delays_min,omitempty"`
-	DelaysMax     []int64                `protobuf:"varint,12,rep,packed,name=delays_max,json=delaysMax,proto3" json:"delays_max,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
@@ -79,6 +79,34 @@ func (x *Config) GetPacketsTo() int64 {
 	return 0
 }
 
+func (x *Config) GetLengthMin() int64 {
+	if x != nil {
+		return x.LengthMin
+	}
+	return 0
+}
+
+func (x *Config) GetLengthMax() int64 {
+	if x != nil {
+		return x.LengthMax
+	}
+	return 0
+}
+
+func (x *Config) GetDelayMin() int64 {
+	if x != nil {
+		return x.DelayMin
+	}
+	return 0
+}
+
+func (x *Config) GetDelayMax() int64 {
+	if x != nil {
+		return x.DelayMax
+	}
+	return 0
+}
+
 func (x *Config) GetMaxSplitMin() int64 {
 	if x != nil {
 		return x.MaxSplitMin
@@ -93,54 +121,23 @@ func (x *Config) GetMaxSplitMax() int64 {
 	return 0
 }
 
-func (x *Config) GetLengthsMin() []int64 {
-	if x != nil {
-		return x.LengthsMin
-	}
-	return nil
-}
-
-func (x *Config) GetLengthsMax() []int64 {
-	if x != nil {
-		return x.LengthsMax
-	}
-	return nil
-}
-
-func (x *Config) GetDelaysMin() []int64 {
-	if x != nil {
-		return x.DelaysMin
-	}
-	return nil
-}
-
-func (x *Config) GetDelaysMax() []int64 {
-	if x != nil {
-		return x.DelaysMax
-	}
-	return nil
-}
-
 var File_transport_internet_finalmask_fragment_config_proto protoreflect.FileDescriptor
 
 const file_transport_internet_finalmask_fragment_config_proto_rawDesc = "" +
 	"\n" +
-	"2transport/internet/finalmask/fragment/config.proto\x12*xray.transport.internet.finalmask.fragment\"\x92\x02\n" +
+	"2transport/internet/finalmask/fragment/config.proto\x12*xray.transport.internet.finalmask.fragment\"\x8a\x02\n" +
 	"\x06Config\x12!\n" +
 	"\fpackets_from\x18\x01 \x01(\x03R\vpacketsFrom\x12\x1d\n" +
 	"\n" +
-	"packets_to\x18\x02 \x01(\x03R\tpacketsTo\x12\"\n" +
+	"packets_to\x18\x02 \x01(\x03R\tpacketsTo\x12\x1d\n" +
+	"\n" +
+	"length_min\x18\x03 \x01(\x03R\tlengthMin\x12\x1d\n" +
+	"\n" +
+	"length_max\x18\x04 \x01(\x03R\tlengthMax\x12\x1b\n" +
+	"\tdelay_min\x18\x05 \x01(\x03R\bdelayMin\x12\x1b\n" +
+	"\tdelay_max\x18\x06 \x01(\x03R\bdelayMax\x12\"\n" +
 	"\rmax_split_min\x18\a \x01(\x03R\vmaxSplitMin\x12\"\n" +
-	"\rmax_split_max\x18\b \x01(\x03R\vmaxSplitMax\x12\x1f\n" +
-	"\vlengths_min\x18\t \x03(\x03R\n" +
-	"lengthsMin\x12\x1f\n" +
-	"\vlengths_max\x18\n" +
-	" \x03(\x03R\n" +
-	"lengthsMax\x12\x1d\n" +
-	"\n" +
-	"delays_min\x18\v \x03(\x03R\tdelaysMin\x12\x1d\n" +
-	"\n" +
-	"delays_max\x18\f \x03(\x03R\tdelaysMaxB\xa0\x01\n" +
+	"\rmax_split_max\x18\b \x01(\x03R\vmaxSplitMaxB\xa0\x01\n" +
 	".com.xray.transport.internet.finalmask.fragmentP\x01Z?github.com/xtls/xray-core/transport/internet/finalmask/fragment\xaa\x02*Xray.Transport.Internet.Finalmask.Fragmentb\x06proto3"
 
 var (

transport/internet/finalmask/fragment/config.proto

@@ -9,10 +9,10 @@ option java_multiple_files = true;
 message Config {
   int64 packets_from = 1;
   int64 packets_to = 2;
+  int64 length_min = 3;
+  int64 length_max = 4;
+  int64 delay_min = 5;
+  int64 delay_max = 6;
   int64 max_split_min = 7;
   int64 max_split_max = 8;
-  repeated int64 lengths_min = 9;
-  repeated int64 lengths_max = 10;
-  repeated int64 delays_min = 11;
-  repeated int64 delays_max = 12;
 }

transport/internet/finalmask/fragment/conn.go

@@ -43,29 +43,6 @@ func (c *fragmentConn) Splice() bool {
 	return true
 }
 
-// lengthForSegment returns the length range (min, max) for the given segment index (0-based).
-// Clamps to the last entry when the index exceeds the list length.
-func (c *fragmentConn) lengthForSegment(segIdx int) (int64, int64) {
-	if segIdx >= len(c.config.LengthsMin) {
-		segIdx = len(c.config.LengthsMin) - 1
-	}
-	return c.config.LengthsMin[segIdx], c.config.LengthsMax[segIdx]
-}
-
-// delayForSegment returns the delay range (min, max) for the given segment index (0-based).
-// Clamps to the last entry when the index exceeds the list length.
-func (c *fragmentConn) delayForSegment(segIdx int) (int64, int64) {
-	if segIdx >= len(c.config.DelaysMin) {
-		segIdx = len(c.config.DelaysMin) - 1
-	}
-	return c.config.DelaysMin[segIdx], c.config.DelaysMax[segIdx]
-}
-
-// mergeTlsHelloSegments returns true only when delays has exactly one zero entry.
-func (c *fragmentConn) mergeTlsHelloSegments() bool {
-	return len(c.config.DelaysMax) == 1 && c.config.DelaysMax[0] == 0
-}
-
 func (c *fragmentConn) Write(p []byte) (n int, err error) {
 	c.count++
 
@@ -80,13 +57,12 @@ func (c *fragmentConn) Write(p []byte) (n int, err error) {
 		data := p[5:recordLen]
 		buff := make([]byte, 2048)
 		var hello []byte
-		mergeHello := c.mergeTlsHelloSegments()
 		maxSplit := crypto.RandBetween(c.config.MaxSplitMin, c.config.MaxSplitMax)
 		var splitNum int64
 		for from := 0; ; {
-			lengthMin, lengthMax := c.lengthForSegment(int(splitNum))
-			to := from + int(crypto.RandBetween(lengthMin, lengthMax))
-			if to > len(data) || (maxSplit > 0 && splitNum+1 >= maxSplit) {
+			to := from + int(crypto.RandBetween(c.config.LengthMin, c.config.LengthMax))
+			splitNum++
+			if to > len(data) || (maxSplit > 0 && splitNum >= maxSplit) {
 				to = len(data)
 			}
 			l := to - from
@@ -98,19 +74,15 @@ func (c *fragmentConn) Write(p []byte) (n int, err error) {
 			from = to
 			buff[3] = byte(l >> 8)
 			buff[4] = byte(l)
-			if mergeHello {
+			if c.config.DelayMax == 0 {
 				hello = append(hello, buff[:5+l]...)
 			} else {
-				delayMin, delayMax := c.delayForSegment(int(splitNum))
 				_, err := c.Conn.Write(buff[:5+l])
-				if delayMax > 0 {
-					time.Sleep(time.Duration(crypto.RandBetween(delayMin, delayMax)) * time.Millisecond)
-				}
+				time.Sleep(time.Duration(crypto.RandBetween(c.config.DelayMin, c.config.DelayMax)) * time.Millisecond)
 				if err != nil {
 					return 0, err
 				}
 			}
-			splitNum++
 			if from == len(data) {
 				if len(hello) > 0 {
 					_, err := c.Conn.Write(hello)
@@ -135,9 +107,9 @@ func (c *fragmentConn) Write(p []byte) (n int, err error) {
 	maxSplit := crypto.RandBetween(c.config.MaxSplitMin, c.config.MaxSplitMax)
 	var splitNum int64
 	for from := 0; ; {
-		lengthMin, lengthMax := c.lengthForSegment(int(splitNum))
-		to := from + int(crypto.RandBetween(lengthMin, lengthMax))
-		if to > len(p) || (maxSplit > 0 && splitNum+1 >= maxSplit) {
+		to := from + int(crypto.RandBetween(c.config.LengthMin, c.config.LengthMax))
+		splitNum++
+		if to > len(p) || (maxSplit > 0 && splitNum >= maxSplit) {
 			to = len(p)
 		}
 		n, err := c.Conn.Write(p[from:to])
@@ -145,11 +117,7 @@ func (c *fragmentConn) Write(p []byte) (n int, err error) {
 		if err != nil {
 			return from, err
 		}
-		delayMin, delayMax := c.delayForSegment(int(splitNum))
-		if delayMax > 0 {
-			time.Sleep(time.Duration(crypto.RandBetween(delayMin, delayMax)) * time.Millisecond)
-		}
-		splitNum++
+		time.Sleep(time.Duration(crypto.RandBetween(c.config.DelayMin, c.config.DelayMax)) * time.Millisecond)
 		if from >= len(p) {
 			return from, nil
 		}

transport/internet/splithttp/hub.go

@@ -146,7 +146,6 @@ func (h *requestHandler) ServeHTTP(writer http.ResponseWriter, request *http.Req
 		writer.WriteHeader(http.StatusBadRequest)
 		return
 	}
-	obfsPaddingAccepted := h.config.XPaddingObfsMode && paddingValue != ""
 
 	sessionId, seqStr := h.config.ExtractMetaFromRequest(request, h.path)
 
@@ -216,8 +215,8 @@ func (h *requestHandler) ServeHTTP(writer http.ResponseWriter, request *http.Req
 				writer.Header().Set("Cache-Control", "no-store")
 				writer.WriteHeader(http.StatusOK)
 				scStreamUpServerSecs := h.config.GetNormalizedScStreamUpServerSecs()
-				hasLegacyRefererCompatMarker := request.Header.Get("Referer") != ""
-				if (hasLegacyRefererCompatMarker || obfsPaddingAccepted) && scStreamUpServerSecs.To > 0 {
+				referrer := request.Header.Get("Referer")
+				if referrer != "" && scStreamUpServerSecs.To > 0 {
 					go func() {
 						for {
 							_, err := httpSC.Write(bytes.Repeat([]byte{'X'}, int(h.config.GetNormalizedXPaddingBytes().rand())))