diff --git a/common/bufio/copy.go b/common/bufio/copy.go
index e48677650..914865a65 100644
--- a/common/bufio/copy.go
+++ b/common/bufio/copy.go
@@ -45,7 +45,7 @@ func Copy(destination io.Writer, source io.Reader) (n int64, err error) {
 		dstSyscallConn, dstIsSyscall := destination.(syscall.Conn)
 		if srcIsSyscall && dstIsSyscall {
 			var handled bool
-			handled, n, err = CopyDirect(srcSyscallConn, dstSyscallConn, readCounters, writeCounters)
+			handled, n, err = copyDirect(srcSyscallConn, dstSyscallConn, readCounters, writeCounters)
 			if handled {
 				return
 			}
diff --git a/common/bufio/copy_direct.go b/common/bufio/copy_direct.go
index 1648c03be..f34d3844a 100644
--- a/common/bufio/copy_direct.go
+++ b/common/bufio/copy_direct.go
@@ -1,12 +1,16 @@
 package bufio
 
 import (
+	"errors"
+	"io"
 	"syscall"
 
+	"github.com/sagernet/sing/common/buf"
+	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
 )
 
-func CopyDirect(source syscall.Conn, destination syscall.Conn, readCounters []N.CountFunc, writeCounters []N.CountFunc) (handed bool, n int64, err error) {
+func copyDirect(source syscall.Conn, destination syscall.Conn, readCounters []N.CountFunc, writeCounters []N.CountFunc) (handed bool, n int64, err error) {
 	rawSource, err := source.SyscallConn()
 	if err != nil {
 		return
@@ -18,3 +22,69 @@ func CopyDirect(source syscall.Conn, destination syscall.Conn, readCounters []N.
 	handed, n, err = splice(rawSource, rawDestination, readCounters, writeCounters)
 	return
 }
+
+func copyWaitWithPool(originSource io.Reader, destination N.ExtendedWriter, source N.ReadWaiter, readCounters []N.CountFunc, writeCounters []N.CountFunc) (handled bool, n int64, err error) {
+	handled = true
+	var (
+		buffer       *buf.Buffer
+		notFirstTime bool
+	)
+	for {
+		buffer, err = source.WaitReadBuffer()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				err = nil
+				return
+			}
+			return
+		}
+		dataLen := buffer.Len()
+		err = destination.WriteBuffer(buffer)
+		if err != nil {
+			buffer.Leak()
+			if !notFirstTime {
+				err = N.ReportHandshakeFailure(originSource, err)
+			}
+			return
+		}
+		n += int64(dataLen)
+		for _, counter := range readCounters {
+			counter(int64(dataLen))
+		}
+		for _, counter := range writeCounters {
+			counter(int64(dataLen))
+		}
+		notFirstTime = true
+	}
+}
+
+func copyPacketWaitWithPool(originSource N.PacketReader, destinationConn N.PacketWriter, source N.PacketReadWaiter, readCounters []N.CountFunc, writeCounters []N.CountFunc, notFirstTime bool) (handled bool, n int64, err error) {
+	handled = true
+	var (
+		buffer      *buf.Buffer
+		destination M.Socksaddr
+	)
+	for {
+		buffer, destination, err = source.WaitReadPacket()
+		if err != nil {
+			return
+		}
+		dataLen := buffer.Len()
+		err = destinationConn.WritePacket(buffer, destination)
+		if err != nil {
+			buffer.Leak()
+			if !notFirstTime {
+				err = N.ReportHandshakeFailure(originSource, err)
+			}
+			return
+		}
+		n += int64(dataLen)
+		for _, counter := range readCounters {
+			counter(int64(dataLen))
+		}
+		for _, counter := range writeCounters {
+			counter(int64(dataLen))
+		}
+		notFirstTime = true
+	}
+}
diff --git a/common/bufio/copy_direct_posix.go b/common/bufio/copy_direct_posix.go
index ce3d3c3a8..f24d53b9e 100644
--- a/common/bufio/copy_direct_posix.go
+++ b/common/bufio/copy_direct_posix.go
@@ -3,7 +3,6 @@
 package bufio
 
 import (
-	"errors"
 	"io"
 	"net/netip"
 	"os"
@@ -15,72 +14,6 @@ import (
 	N "github.com/sagernet/sing/common/network"
 )
 
-func copyWaitWithPool(originSource io.Reader, destination N.ExtendedWriter, source N.ReadWaiter, readCounters []N.CountFunc, writeCounters []N.CountFunc) (handled bool, n int64, err error) {
-	handled = true
-	var (
-		buffer       *buf.Buffer
-		notFirstTime bool
-	)
-	for {
-		buffer, err = source.WaitReadBuffer()
-		if err != nil {
-			if errors.Is(err, io.EOF) {
-				err = nil
-				return
-			}
-			return
-		}
-		dataLen := buffer.Len()
-		err = destination.WriteBuffer(buffer)
-		if err != nil {
-			buffer.Leak()
-			if !notFirstTime {
-				err = N.ReportHandshakeFailure(originSource, err)
-			}
-			return
-		}
-		n += int64(dataLen)
-		for _, counter := range readCounters {
-			counter(int64(dataLen))
-		}
-		for _, counter := range writeCounters {
-			counter(int64(dataLen))
-		}
-		notFirstTime = true
-	}
-}
-
-func copyPacketWaitWithPool(originSource N.PacketReader, destinationConn N.PacketWriter, source N.PacketReadWaiter, readCounters []N.CountFunc, writeCounters []N.CountFunc, notFirstTime bool) (handled bool, n int64, err error) {
-	handled = true
-	var (
-		buffer      *buf.Buffer
-		destination M.Socksaddr
-	)
-	for {
-		buffer, destination, err = source.WaitReadPacket()
-		if err != nil {
-			return
-		}
-		dataLen := buffer.Len()
-		err = destinationConn.WritePacket(buffer, destination)
-		if err != nil {
-			buffer.Leak()
-			if !notFirstTime {
-				err = N.ReportHandshakeFailure(originSource, err)
-			}
-			return
-		}
-		n += int64(dataLen)
-		for _, counter := range readCounters {
-			counter(int64(dataLen))
-		}
-		for _, counter := range writeCounters {
-			counter(int64(dataLen))
-		}
-		notFirstTime = true
-	}
-}
-
 var _ N.ReadWaiter = (*syscallReadWaiter)(nil)
 
 type syscallReadWaiter struct {
diff --git a/common/bufio/copy_direct_windows.go b/common/bufio/copy_direct_windows.go
index 22a2de095..b6317aad5 100644
--- a/common/bufio/copy_direct_windows.go
+++ b/common/bufio/copy_direct_windows.go
@@ -1,19 +1,9 @@
 package bufio
 
 import (
-	"io"
-
 	N "github.com/sagernet/sing/common/network"
 )
 
-func copyWaitWithPool(originSource io.Reader, destination N.ExtendedWriter, source N.ReadWaiter, readCounters []N.CountFunc, writeCounters []N.CountFunc) (handled bool, n int64, err error) {
-	return
-}
-
-func copyPacketWaitWithPool(originSource N.PacketReader, destinationConn N.PacketWriter, source N.PacketReadWaiter, readCounters []N.CountFunc, writeCounters []N.CountFunc, notFirstTime bool) (handled bool, n int64, err error) {
-	return
-}
-
 func createSyscallReadWaiter(reader any) (N.ReadWaiter, bool) {
 	return nil, false
 }