Update tfo-go

common/dialer/default.go

@@ -13,12 +13,11 @@ import (
 	E "github.com/sagernet/sing/common/exceptions"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
-	"github.com/sagernet/tfo-go"
 )
 
 type DefaultDialer struct {
-	dialer4     tfo.Dialer
-	dialer6     tfo.Dialer
+	dialer4     tcpDialer
+	dialer6     tcpDialer
 	udpDialer4  net.Dialer
 	udpDialer6  net.Dialer
 	udpListener net.ListenConfig
@@ -94,14 +93,22 @@ func NewDefault(router adapter.Router, options option.DialerOptions) (*DefaultDi
 		udpAddr6 = M.SocksaddrFrom(bindAddr, 0).String()
 	}
 	if options.TCPMultiPath {
-		if !multipathTCPAvailable {
+		if !go121Available {
 			return nil, E.New("MultiPath TCP requires go1.21, please recompile your binary.")
 		}
 		setMultiPathTCP(&dialer4)
 	}
+	tcpDialer4, err := newTCPDialer(dialer4, options.TCPFastOpen)
+	if err != nil {
+		return nil, err
+	}
+	tcpDialer6, err := newTCPDialer(dialer6, options.TCPFastOpen)
+	if err != nil {
+		return nil, err
+	}
 	return &DefaultDialer{
-		tfo.Dialer{Dialer: dialer4, DisableTFO: !options.TCPFastOpen},
-		tfo.Dialer{Dialer: dialer6, DisableTFO: !options.TCPFastOpen},
+		tcpDialer4,
+		tcpDialer6,
 		udpDialer4,
 		udpDialer6,
 		listener,

common/dialer/default_go1.20.go

@@ -0,0 +1,15 @@
+//go:build go1.20
+
+package dialer
+
+import (
+	"net"
+
+	"github.com/sagernet/tfo-go"
+)
+
+type tcpDialer = tfo.Dialer
+
+func newTCPDialer(dialer net.Dialer, tfoEnabled bool) (tcpDialer, error) {
+	return tfo.Dialer{Dialer: dialer, DisableTFO: !tfoEnabled}, nil
+}

common/dialer/default_go1.21.go

@@ -4,7 +4,7 @@ package dialer
 
 import "net"
 
-const multipathTCPAvailable = true
+const go121Available = true
 
 func setMultiPathTCP(dialer *net.Dialer) {
 	dialer.SetMultipathTCP(true)

common/dialer/default_nongo1.20.go

@@ -0,0 +1,18 @@
+//go:build !go1.20
+
+package dialer
+
+import (
+	"net"
+
+	E "github.com/sagernet/sing/common/exceptions"
+)
+
+type tcpDialer = net.Dialer
+
+func newTCPDialer(dialer net.Dialer, tfoEnabled bool) (tcpDialer, error) {
+	if tfoEnabled {
+		return dialer, E.New("TCP Fast Open requires go1.20, please recompile your binary.")
+	}
+	return dialer, nil
+}

common/dialer/default_nongo1.21.go

@@ -6,7 +6,7 @@ import (
 	"net"
 )
 
-const multipathTCPAvailable = false
+const go121Available = false
 
 func setMultiPathTCP(dialer *net.Dialer) {
 }

common/dialer/tfo.go

@@ -1,3 +1,5 @@
+//go:build go1.20
+
 package dialer
 
 import (
@@ -25,7 +27,7 @@ type slowOpenConn struct {
 	err         error
 }
 
-func DialSlowContext(dialer *tfo.Dialer, ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+func DialSlowContext(dialer *tcpDialer, ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
 	if dialer.DisableTFO || N.NetworkName(network) != N.NetworkTCP {
 		switch N.NetworkName(network) {
 		case N.NetworkTCP, N.NetworkUDP:
@@ -61,6 +63,7 @@ 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)
 		if err != nil {
+			c.conn = nil
 			c.err = E.Cause(err, "dial tcp fast open")
 		}
 		close(c.create)

common/dialer/tfo_stub.go

@@ -0,0 +1,20 @@
+//go:build !go1.20
+
+package dialer
+
+import (
+	"context"
+	"net"
+
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+func DialSlowContext(dialer *tcpDialer, ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	switch N.NetworkName(network) {
+	case N.NetworkTCP, N.NetworkUDP:
+		return dialer.DialContext(ctx, network, destination.String())
+	default:
+		return dialer.DialContext(ctx, network, destination.AddrString())
+	}
+}