Add support for kTLS

Reference: https://gitlab.com/go-extension/tls

common/badtls/read_wait.go

@@ -1,18 +1,9 @@
-//go:build go1.21 && !without_badtls
+//go:build go1.25 && !without_badtls
 
 package badtls
 
 import (
-	"bytes"
-	"context"
-	"net"
-	"os"
-	"reflect"
-	"sync"
-	"unsafe"
-
 	"github.com/sagernet/sing/common/buf"
-	E "github.com/sagernet/sing/common/exceptions"
 	N "github.com/sagernet/sing/common/network"
 	"github.com/sagernet/sing/common/tls"
 )
@@ -21,63 +12,21 @@ var _ N.ReadWaiter = (*ReadWaitConn)(nil)
 
 type ReadWaitConn struct {
 	tls.Conn
-	halfAccess                    *sync.Mutex
-	rawInput                      *bytes.Buffer
-	input                         *bytes.Reader
-	hand                          *bytes.Buffer
-	readWaitOptions               N.ReadWaitOptions
-	tlsReadRecord                 func() error
-	tlsHandlePostHandshakeMessage func() error
+	rawConn         *RawConn
+	readWaitOptions N.ReadWaitOptions
 }
 
 func NewReadWaitConn(conn tls.Conn) (tls.Conn, error) {
-	var (
-		loaded                        bool
-		tlsReadRecord                 func() error
-		tlsHandlePostHandshakeMessage func() error
-	)
-	for _, tlsCreator := range tlsRegistry {
-		loaded, tlsReadRecord, tlsHandlePostHandshakeMessage = tlsCreator(conn)
-		if loaded {
-			break
-		}
+	if _, isReadWaitConn := conn.(N.ReadWaiter); isReadWaitConn {
+		return conn, nil
 	}
-	if !loaded {
-		return nil, os.ErrInvalid
+	rawConn, err := NewRawConn(conn)
+	if err != nil {
+		return nil, err
 	}
-	rawConn := reflect.Indirect(reflect.ValueOf(conn))
-	rawHalfConn := rawConn.FieldByName("in")
-	if !rawHalfConn.IsValid() || rawHalfConn.Kind() != reflect.Struct {
-		return nil, E.New("badtls: invalid half conn")
-	}
-	rawHalfMutex := rawHalfConn.FieldByName("Mutex")
-	if !rawHalfMutex.IsValid() || rawHalfMutex.Kind() != reflect.Struct {
-		return nil, E.New("badtls: invalid half mutex")
-	}
-	halfAccess := (*sync.Mutex)(unsafe.Pointer(rawHalfMutex.UnsafeAddr()))
-	rawRawInput := rawConn.FieldByName("rawInput")
-	if !rawRawInput.IsValid() || rawRawInput.Kind() != reflect.Struct {
-		return nil, E.New("badtls: invalid raw input")
-	}
-	rawInput := (*bytes.Buffer)(unsafe.Pointer(rawRawInput.UnsafeAddr()))
-	rawInput0 := rawConn.FieldByName("input")
-	if !rawInput0.IsValid() || rawInput0.Kind() != reflect.Struct {
-		return nil, E.New("badtls: invalid input")
-	}
-	input := (*bytes.Reader)(unsafe.Pointer(rawInput0.UnsafeAddr()))
-	rawHand := rawConn.FieldByName("hand")
-	if !rawHand.IsValid() || rawHand.Kind() != reflect.Struct {
-		return nil, E.New("badtls: invalid hand")
-	}
-	hand := (*bytes.Buffer)(unsafe.Pointer(rawHand.UnsafeAddr()))
 	return &ReadWaitConn{
-		Conn:                          conn,
-		halfAccess:                    halfAccess,
-		rawInput:                      rawInput,
-		input:                         input,
-		hand:                          hand,
-		tlsReadRecord:                 tlsReadRecord,
-		tlsHandlePostHandshakeMessage: tlsHandlePostHandshakeMessage,
+		Conn:    conn,
+		rawConn: rawConn,
 	}, nil
 }
 
@@ -87,36 +36,36 @@ func (c *ReadWaitConn) InitializeReadWaiter(options N.ReadWaitOptions) (needCopy
 }
 
 func (c *ReadWaitConn) WaitReadBuffer() (buffer *buf.Buffer, err error) {
-	err = c.HandshakeContext(context.Background())
-	if err != nil {
-		return
-	}
-	c.halfAccess.Lock()
-	defer c.halfAccess.Unlock()
-	for c.input.Len() == 0 {
-		err = c.tlsReadRecord()
+	//err = c.HandshakeContext(context.Background())
+	//if err != nil {
+	//	return
+	//}
+	c.rawConn.In.Lock()
+	defer c.rawConn.In.Unlock()
+	for c.rawConn.Input.Len() == 0 {
+		err = c.rawConn.ReadRecord()
 		if err != nil {
 			return
 		}
-		for c.hand.Len() > 0 {
-			err = c.tlsHandlePostHandshakeMessage()
+		for c.rawConn.Hand.Len() > 0 {
+			err = c.rawConn.HandlePostHandshakeMessage()
 			if err != nil {
 				return
 			}
 		}
 	}
 	buffer = c.readWaitOptions.NewBuffer()
-	n, err := c.input.Read(buffer.FreeBytes())
+	n, err := c.rawConn.Input.Read(buffer.FreeBytes())
 	if err != nil {
 		buffer.Release()
 		return
 	}
 	buffer.Truncate(n)
 
-	if n != 0 && c.input.Len() == 0 && c.rawInput.Len() > 0 &&
-		// recordType(c.rawInput.Bytes()[0]) == recordTypeAlert {
-		c.rawInput.Bytes()[0] == 21 {
-		_ = c.tlsReadRecord()
+	if n != 0 && c.rawConn.Input.Len() == 0 && c.rawConn.Input.Len() > 0 &&
+		// recordType(c.RawInput.Bytes()[0]) == recordTypeAlert {
+		c.rawConn.RawInput.Bytes()[0] == 21 {
+		_ = c.rawConn.ReadRecord()
 		// return n, err // will be io.EOF on closeNotify
 	}
 
@@ -131,25 +80,3 @@ func (c *ReadWaitConn) Upstream() any {
 func (c *ReadWaitConn) ReaderReplaceable() bool {
 	return true
 }
-
-var tlsRegistry []func(conn net.Conn) (loaded bool, tlsReadRecord func() error, tlsHandlePostHandshakeMessage func() error)
-
-func init() {
-	tlsRegistry = append(tlsRegistry, func(conn net.Conn) (loaded bool, tlsReadRecord func() error, tlsHandlePostHandshakeMessage func() error) {
-		tlsConn, loaded := conn.(*tls.STDConn)
-		if !loaded {
-			return
-		}
-		return true, func() error {
-				return stdTLSReadRecord(tlsConn)
-			}, func() error {
-				return stdTLSHandlePostHandshakeMessage(tlsConn)
-			}
-	})
-}
-
-//go:linkname stdTLSReadRecord crypto/tls.(*Conn).readRecord
-func stdTLSReadRecord(c *tls.STDConn) error
-
-//go:linkname stdTLSHandlePostHandshakeMessage crypto/tls.(*Conn).handlePostHandshakeMessage
-func stdTLSHandlePostHandshakeMessage(c *tls.STDConn) error