feat(server): tcp fast open on direct outbounds

app/cmd/server.go

@@ -204,6 +204,7 @@ type serverConfigOutboundDirect struct {
 	BindIPv4   string `mapstructure:"bindIPv4"`
 	BindIPv6   string `mapstructure:"bindIPv6"`
 	BindDevice string `mapstructure:"bindDevice"`
+	FastOpen   bool   `mapstructure:"fastOpen"`
 }
 
 type serverConfigOutboundSOCKS5 struct {
@@ -518,18 +519,18 @@ func (c *serverConfig) fillQUICConfig(hyConfig *server.Config) error {
 }
 
 func serverConfigOutboundDirectToOutbound(c serverConfigOutboundDirect) (outbounds.PluggableOutbound, error) {
-	var mode outbounds.DirectOutboundMode
+	opts := outbounds.DirectOutboundOptions{}
 	switch strings.ToLower(c.Mode) {
 	case "", "auto":
-		mode = outbounds.DirectOutboundModeAuto
+		opts.Mode = outbounds.DirectOutboundModeAuto
 	case "64":
-		mode = outbounds.DirectOutboundMode64
+		opts.Mode = outbounds.DirectOutboundMode64
 	case "46":
-		mode = outbounds.DirectOutboundMode46
+		opts.Mode = outbounds.DirectOutboundMode46
 	case "6":
-		mode = outbounds.DirectOutboundMode6
+		opts.Mode = outbounds.DirectOutboundMode6
 	case "4":
-		mode = outbounds.DirectOutboundMode4
+		opts.Mode = outbounds.DirectOutboundMode4
 	default:
 		return nil, configError{Field: "outbounds.direct.mode", Err: errors.New("unsupported mode")}
 	}
@@ -546,12 +547,14 @@ func serverConfigOutboundDirectToOutbound(c serverConfigOutboundDirect) (outboun
 		if len(c.BindIPv6) > 0 && ip6 == nil {
 			return nil, configError{Field: "outbounds.direct.bindIPv6", Err: errors.New("invalid IPv6 address")}
 		}
-		return outbounds.NewDirectOutboundBindToIPs(mode, ip4, ip6)
+		opts.BindIP4 = ip4
+		opts.BindIP6 = ip6
 	}
 	if bindDevice {
-		return outbounds.NewDirectOutboundBindToDevice(mode, c.BindDevice)
+		opts.DeviceName = c.BindDevice
 	}
-	return outbounds.NewDirectOutboundSimple(mode), nil
+	opts.FastOpen = c.FastOpen
+	return outbounds.NewDirectOutboundWithOptions(opts)
 }
 
 func serverConfigOutboundSOCKS5ToOutbound(c serverConfigOutboundSOCKS5) (outbounds.PluggableOutbound, error) {

app/cmd/server_test.go

@@ -138,6 +138,7 @@ func TestServerConfig(t *testing.T) {
 					BindIPv4:   "2.4.6.8",
 					BindIPv6:   "0:0:0:0:0:ffff:0204:0608",
 					BindDevice: "eth233",
+					FastOpen:   true,
 				},
 			},
 			{

app/cmd/server_test.yaml

@@ -108,6 +108,7 @@ outbounds:
       bindIPv4: 2.4.6.8
       bindIPv6: 0:0:0:0:0:ffff:0204:0608
       bindDevice: eth233
+      fastOpen: true
   - name: badstuff
     type: socks5
     socks5:

app/go.mod

@@ -25,14 +25,16 @@ require (
 	github.com/txthinking/socks5 v0.0.0-20230325130024-4230056ae301
 	go.uber.org/zap v1.24.0
 	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842
-	golang.org/x/sys v0.23.0
+	golang.org/x/sys v0.25.0
 )
 
 require (
 	github.com/andybalholm/brotli v1.1.0 // indirect
 	github.com/apernet/quic-go v0.48.2-0.20241104191913-cb103fcecfe7 // indirect
 	github.com/babolivier/go-doh-client v0.0.0-20201028162107-a76cff4cb8b6 // indirect
 	github.com/cloudflare/circl v1.3.9 // indirect
+	github.com/database64128/netx-go v0.0.0-20240905055117-62795b8b054a // indirect
+	github.com/database64128/tfo-go/v2 v2.2.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/go-ole/go-ole v1.3.0 // indirect

app/go.sum

@@ -63,6 +63,10 @@ github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGX
 github.com/cncf/udpa/go v0.0.0-20200629203442-efcf912fb354/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/database64128/netx-go v0.0.0-20240905055117-62795b8b054a h1:t4SDi0pmNkryzKdM4QF3o5vqSP4GRjeZD/6j3nyxNP0=
+github.com/database64128/netx-go v0.0.0-20240905055117-62795b8b054a/go.mod h1:7K2NQKbabB5mBl41vF6YayYl5g7YpDwc4dQ5iMpP3Lg=
+github.com/database64128/tfo-go/v2 v2.2.2 h1:BxynF4qGF5ct3DpPLEG62uyJZ3LQhqaf0Ken+kyy7PM=
+github.com/database64128/tfo-go/v2 v2.2.2/go.mod h1:2IW8jppdBwdVMjA08uEyMNnqiAHKUlqAA+J8NrsfktY=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 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=
@@ -463,8 +467,8 @@ golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.23.0 h1:YfKFowiIMvtgl1UERQoTPPToxltDeZfbj4H7dVUCwmM=
-golang.org/x/sys v0.23.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.2.0/go.mod h1:TVmDHMZPmdnySmBfhjOoOdhjzdE1h4u1VwSiw2l1Nuc=

extras/go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/apernet/hysteria/core/v2 v2.0.0-00010101000000-000000000000
 	github.com/apernet/quic-go v0.48.2-0.20241104191913-cb103fcecfe7
 	github.com/babolivier/go-doh-client v0.0.0-20201028162107-a76cff4cb8b6
+	github.com/database64128/tfo-go/v2 v2.2.2
 	github.com/hashicorp/golang-lru/v2 v2.0.5
 	github.com/miekg/dns v1.1.59
 	github.com/refraction-networking/utls v1.6.6
@@ -21,6 +22,7 @@ require (
 require (
 	github.com/andybalholm/brotli v1.1.0 // indirect
 	github.com/cloudflare/circl v1.3.9 // indirect
+	github.com/database64128/netx-go v0.0.0-20240905055117-62795b8b054a // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 // indirect
 	github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38 // indirect
@@ -36,7 +38,7 @@ require (
 	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 // indirect
 	golang.org/x/mod v0.17.0 // indirect
 	golang.org/x/sync v0.8.0 // indirect
-	golang.org/x/sys v0.23.0 // indirect
+	golang.org/x/sys v0.25.0 // indirect
 	golang.org/x/text v0.17.0 // indirect
 	golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

extras/go.sum

@@ -10,6 +10,10 @@ github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMn
 github.com/cloudflare/circl v1.3.9 h1:QFrlgFYf2Qpi8bSpVPK1HBvWpx16v/1TZivyo7pGuBE=
 github.com/cloudflare/circl v1.3.9/go.mod h1:PDRU+oXvdD7KCtgKxW95M5Z8BpSCJXQORiZFnBQS5QU=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
+github.com/database64128/netx-go v0.0.0-20240905055117-62795b8b054a h1:t4SDi0pmNkryzKdM4QF3o5vqSP4GRjeZD/6j3nyxNP0=
+github.com/database64128/netx-go v0.0.0-20240905055117-62795b8b054a/go.mod h1:7K2NQKbabB5mBl41vF6YayYl5g7YpDwc4dQ5iMpP3Lg=
+github.com/database64128/tfo-go/v2 v2.2.2 h1:BxynF4qGF5ct3DpPLEG62uyJZ3LQhqaf0Ken+kyy7PM=
+github.com/database64128/tfo-go/v2 v2.2.2/go.mod h1:2IW8jppdBwdVMjA08uEyMNnqiAHKUlqAA+J8NrsfktY=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 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=
@@ -92,8 +96,8 @@ golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.23.0 h1:YfKFowiIMvtgl1UERQoTPPToxltDeZfbj4H7dVUCwmM=
-golang.org/x/sys v0.23.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.2.0/go.mod h1:TVmDHMZPmdnySmBfhjOoOdhjzdE1h4u1VwSiw2l1Nuc=

extras/outbounds/fastopen.go

@@ -0,0 +1,229 @@
+package outbounds
+
+import (
+	"net"
+	"sync"
+	"time"
+
+	"github.com/database64128/tfo-go/v2"
+)
+
+type fastOpenDialer struct {
+	dialer *tfo.Dialer
+}
+
+func newFastOpenDialer(netDialer *net.Dialer) *fastOpenDialer {
+	return &fastOpenDialer{
+		dialer: &tfo.Dialer{
+			Dialer: *netDialer,
+		},
+	}
+}
+
+// Dial returns immediately without actually establishing a connection.
+// The connection will be established by the first Write() call.
+func (d *fastOpenDialer) Dial(network, address string) (net.Conn, error) {
+	return &fastOpenConn{
+		dialer:    d.dialer,
+		network:   network,
+		address:   address,
+		readyChan: make(chan struct{}),
+	}, nil
+}
+
+type fastOpenConn struct {
+	dialer  *tfo.Dialer
+	network string
+	address string
+
+	conn      net.Conn
+	connLock  sync.RWMutex
+	readyChan chan struct{}
+
+	// States before connection ready
+	deadline      *time.Time
+	readDeadline  *time.Time
+	writeDeadline *time.Time
+}
+
+func (c *fastOpenConn) Read(b []byte) (n int, err error) {
+	c.connLock.RLock()
+	conn := c.conn
+	c.connLock.RUnlock()
+
+	if conn != nil {
+		return conn.Read(b)
+	}
+
+	// Wait until the connection is ready or closed
+	<-c.readyChan
+
+	if c.conn == nil {
+		// This is equivalent to isClosedBeforeReady() == true
+		return 0, net.ErrClosed
+	}
+
+	return c.conn.Read(b)
+}
+
+func (c *fastOpenConn) Write(b []byte) (n int, err error) {
+	c.connLock.RLock()
+	conn := c.conn
+	c.connLock.RUnlock()
+
+	if conn != nil {
+		return conn.Write(b)
+	}
+
+	c.connLock.RLock()
+	closed := c.isClosedBeforeReady()
+	c.connLock.RUnlock()
+
+	if closed {
+		return 0, net.ErrClosed
+	}
+
+	c.connLock.Lock()
+	defer c.connLock.Unlock()
+
+	if c.isClosedBeforeReady() {
+		// Closed by other goroutine
+		return 0, net.ErrClosed
+	}
+
+	conn = c.conn
+	if conn != nil {
+		// Established by other goroutine
+		return conn.Write(b)
+	}
+
+	conn, err = c.dialer.Dial(c.network, c.address, b)
+	if err != nil {
+		close(c.readyChan)
+		return 0, err
+	}
+
+	// Apply pre-set states
+	if c.deadline != nil {
+		_ = conn.SetDeadline(*c.deadline)
+	}
+	if c.readDeadline != nil {
+		_ = conn.SetReadDeadline(*c.readDeadline)
+	}
+	if c.writeDeadline != nil {
+		_ = conn.SetWriteDeadline(*c.writeDeadline)
+	}
+
+	c.conn = conn
+	close(c.readyChan)
+	return len(b), nil
+}
+
+func (c *fastOpenConn) Close() error {
+	c.connLock.RLock()
+	defer c.connLock.RUnlock()
+
+	if c.isClosedBeforeReady() {
+		return net.ErrClosed
+	}
+
+	if c.conn != nil {
+		return c.conn.Close()
+	}
+
+	close(c.readyChan)
+	return nil
+}
+
+// isClosedBeforeReady returns true if the connection is closed before the real connection is established.
+// This function should be called with connLock.RLock().
+func (c *fastOpenConn) isClosedBeforeReady() bool {
+	select {
+	case <-c.readyChan:
+		if c.conn == nil {
+			return true
+		}
+	default:
+	}
+	return false
+}
+
+func (c *fastOpenConn) LocalAddr() net.Addr {
+	c.connLock.RLock()
+	defer c.connLock.RUnlock()
+
+	if c.conn != nil {
+		return c.conn.LocalAddr()
+	}
+
+	return nil
+}
+
+func (c *fastOpenConn) RemoteAddr() net.Addr {
+	c.connLock.RLock()
+	conn := c.conn
+	c.connLock.RUnlock()
+
+	if conn != nil {
+		return conn.RemoteAddr()
+	}
+
+	addr, err := net.ResolveTCPAddr(c.network, c.address)
+	if err != nil {
+		return nil
+	}
+	return addr
+}
+
+func (c *fastOpenConn) SetDeadline(t time.Time) error {
+	c.connLock.RLock()
+	defer c.connLock.RUnlock()
+
+	c.deadline = &t
+
+	if c.conn != nil {
+		return c.conn.SetDeadline(t)
+	}
+
+	if c.isClosedBeforeReady() {
+		return net.ErrClosed
+	}
+
+	return nil
+}
+
+func (c *fastOpenConn) SetReadDeadline(t time.Time) error {
+	c.connLock.RLock()
+	defer c.connLock.RUnlock()
+
+	c.readDeadline = &t
+
+	if c.conn != nil {
+		return c.conn.SetReadDeadline(t)
+	}
+
+	if c.isClosedBeforeReady() {
+		return net.ErrClosed
+	}
+
+	return nil
+}
+
+func (c *fastOpenConn) SetWriteDeadline(t time.Time) error {
+	c.connLock.RLock()
+	defer c.connLock.RUnlock()
+
+	c.writeDeadline = &t
+
+	if c.conn != nil {
+		return c.conn.SetWriteDeadline(t)
+	}
+
+	if c.isClosedBeforeReady() {
+		return net.ErrClosed
+	}
+
+	return nil
+}
+
+var _ net.Conn = (*fastOpenConn)(nil)