Update tfo-go usage

common/dialer/default.go

@@ -15,7 +15,7 @@ import (
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
 
-	"github.com/database64128/tfo-go"
+	"github.com/database64128/tfo-go/v2"
 )
 
 var warnBindInterfaceOnUnsupportedPlatform = warning.New(
@@ -146,7 +146,7 @@ func (d *DefaultDialer) DialContext(ctx context.Context, network string, address
 	case N.NetworkUDP:
 		return d.udpDialer.DialContext(ctx, network, address.String())
 	}
-	return d.dialer.DialContext(ctx, network, address.String())
+	return DialSlowContext(&d.dialer, ctx, network, address)
 }
 
 func (d *DefaultDialer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {

common/dialer/tfo.go

@@ -0,0 +1,135 @@
+package dialer
+
+import (
+	"context"
+	"io"
+	"net"
+	"os"
+	"time"
+
+	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/bufio"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+
+	"github.com/database64128/tfo-go/v2"
+)
+
+type slowOpenConn struct {
+	dialer      *tfo.Dialer
+	ctx         context.Context
+	network     string
+	destination M.Socksaddr
+	conn        net.Conn
+	create      chan struct{}
+	err         error
+}
+
+func DialSlowContext(dialer *tfo.Dialer, ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	if dialer.DisableTFO || N.NetworkName(network) != N.NetworkTCP {
+		return dialer.DialContext(ctx, network, destination.String(), nil)
+	}
+	return &slowOpenConn{
+		dialer:      dialer,
+		ctx:         ctx,
+		network:     network,
+		destination: destination,
+		create:      make(chan struct{}),
+	}, nil
+}
+
+func (c *slowOpenConn) Read(b []byte) (n int, err error) {
+	if c.conn == nil {
+		select {
+		case <-c.create:
+			if c.err != nil {
+				return 0, c.err
+			}
+		case <-c.ctx.Done():
+			return 0, c.ctx.Err()
+		}
+	}
+	return c.conn.Read(b)
+}
+
+func (c *slowOpenConn) Write(b []byte) (n int, err error) {
+	if c.conn == nil {
+		c.conn, err = c.dialer.DialContext(c.ctx, c.network, c.destination.String(), b)
+		c.err = err
+		close(c.create)
+		return
+	}
+	return c.conn.Write(b)
+}
+
+func (c *slowOpenConn) Close() error {
+	return common.Close(c.conn)
+}
+
+func (c *slowOpenConn) LocalAddr() net.Addr {
+	if c.conn == nil {
+		return M.Socksaddr{}
+	}
+	return c.conn.LocalAddr()
+}
+
+func (c *slowOpenConn) RemoteAddr() net.Addr {
+	if c.conn == nil {
+		return M.Socksaddr{}
+	}
+	return c.conn.RemoteAddr()
+}
+
+func (c *slowOpenConn) SetDeadline(t time.Time) error {
+	if c.conn == nil {
+		return os.ErrInvalid
+	}
+	return c.conn.SetDeadline(t)
+}
+
+func (c *slowOpenConn) SetReadDeadline(t time.Time) error {
+	if c.conn == nil {
+		return os.ErrInvalid
+	}
+	return c.conn.SetReadDeadline(t)
+}
+
+func (c *slowOpenConn) SetWriteDeadline(t time.Time) error {
+	if c.conn == nil {
+		return os.ErrInvalid
+	}
+	return c.conn.SetWriteDeadline(t)
+}
+
+func (c *slowOpenConn) Upstream() any {
+	return c.conn
+}
+
+func (c *slowOpenConn) ReaderReplaceable() bool {
+	return c.conn != nil
+}
+
+func (c *slowOpenConn) WriterReplaceable() bool {
+	return c.conn != nil
+}
+
+func (c *slowOpenConn) ReadFrom(r io.Reader) (n int64, err error) {
+	if c.conn != nil {
+		return bufio.Copy(c.conn, r)
+	}
+	return bufio.ReadFrom0(c, r)
+}
+
+func (c *slowOpenConn) WriteTo(w io.Writer) (n int64, err error) {
+	if c.conn == nil {
+		select {
+		case <-c.create:
+			if c.err != nil {
+				return 0, c.err
+			}
+		case <-c.ctx.Done():
+			return 0, c.ctx.Err()
+		}
+	}
+	return bufio.Copy(w, c.conn)
+}