tsnet: add Dial method to allow dialing out to the tailnet.

Maisem Ali · maisem · commit 44937b59e70a · 2021-12-28T10:19:36.000-08:00
Signed-off-by: Maisem Ali &lt;maisem@tailscale.com&gt;
diff --git a/tsnet/tsnet.go b/tsnet/tsnet.go
@@ -63,6 +63,15 @@ type Server struct {
 
 	mu        sync.Mutex
 	listeners map[listenKey]*listener
+	dialer    *tsdial.Dialer
+}
+
+// Dial connects to the address on the tailnet.
+func (s *Server) Dial(ctx context.Context, network, address string) (net.Conn, error) {
+	if err := s.init(); err != nil {
+		return nil, err
+	}
+	return s.dialer.UserDial(ctx, network, address)
 }
 
 func (s *Server) doInit() {
@@ -71,6 +80,11 @@ func (s *Server) doInit() {
 	}
 }
 
+func (s *Server) init() error {
+	s.initOnce.Do(s.doInit)
+	return s.initErr
+}
+
 func (s *Server) start() error {
 	if v, _ := strconv.ParseBool(os.Getenv("TAILSCALE_USE_WIP_CODE")); !v {
 		return errors.New("code disabled without environment variable TAILSCALE_USE_WIP_CODE set true")
@@ -117,11 +131,11 @@ func (s *Server) start() error {
 		return err
 	}
 
-	dialer := new(tsdial.Dialer) // mutated below (before used)
+	s.dialer = new(tsdial.Dialer) // mutated below (before used)
 	eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
 		ListenPort:  0,
 		LinkMonitor: linkMon,
-		Dialer:      dialer,
+		Dialer:      s.dialer,
 	})
 	if err != nil {
 		return err
@@ -132,7 +146,7 @@ func (s *Server) start() error {
 		return fmt.Errorf("%T is not a wgengine.InternalsGetter", eng)
 	}
 
-	ns, err := netstack.Create(logf, tunDev, eng, magicConn, dialer)
+	ns, err := netstack.Create(logf, tunDev, eng, magicConn, s.dialer)
 	if err != nil {
 		return fmt.Errorf("netstack.Create: %w", err)
 	}
@@ -141,11 +155,11 @@ func (s *Server) start() error {
 	if err := ns.Start(); err != nil {
 		return fmt.Errorf("failed to start netstack: %w", err)
 	}
-	dialer.UseNetstackForIP = func(ip netaddr.IP) bool {
+	s.dialer.UseNetstackForIP = func(ip netaddr.IP) bool {
 		_, ok := eng.PeerForIP(ip)
 		return ok
 	}
-	dialer.NetstackDialTCP = func(ctx context.Context, dst netaddr.IPPort) (net.Conn, error) {
+	s.dialer.NetstackDialTCP = func(ctx context.Context, dst netaddr.IPPort) (net.Conn, error) {
 		return ns.DialContextTCP(ctx, dst)
 	}
 
@@ -156,7 +170,7 @@ func (s *Server) start() error {
 	}
 	logid := "tslib-TODO"
 
-	lb, err := ipnlocal.NewLocalBackend(logf, logid, store, dialer, eng)
+	lb, err := ipnlocal.NewLocalBackend(logf, logid, store, s.dialer, eng)
 	if err != nil {
 		return fmt.Errorf("NewLocalBackend: %v", err)
 	}
@@ -217,15 +231,15 @@ func (s *Server) forwardTCP(c net.Conn, port uint16) {
 	}
 }
 
+// Listen announces only on the Tailscale network.
 func (s *Server) Listen(network, addr string) (net.Listener, error) {
 	host, port, err := net.SplitHostPort(addr)
 	if err != nil {
 		return nil, fmt.Errorf("tsnet: %w", err)
 	}
 
-	s.initOnce.Do(s.doInit)
-	if s.initErr != nil {
-		return nil, s.initErr
+	if err := s.init(); err != nil {
+		return nil, err
 	}
 
 	key := listenKey{network, host, port}

Original file line number	Diff line number	Diff line change
`@@ -63,6 +63,15 @@ type Server struct {`
`63`	`63`
`64`	`64`	`mu sync.Mutex`
`65`	`65`	`listeners map[listenKey]*listener`
	`66`	`+ dialer *tsdial.Dialer`
	`67`	`+}`
	`68`	`+`
	`69`	`+// Dial connects to the address on the tailnet.`
	`70`	`+func (s *Server) Dial(ctx context.Context, network, address string) (net.Conn, error) {`
	`71`	`+ if err := s.init(); err != nil {`
	`72`	`+ return nil, err`
	`73`	`+ }`
	`74`	`+ return s.dialer.UserDial(ctx, network, address)`
`66`	`75`	`}`
`67`	`76`
`68`	`77`	`func (s *Server) doInit() {`
`@@ -71,6 +80,11 @@ func (s *Server) doInit() {`
`71`	`80`	`}`
`72`	`81`	`}`
`73`	`82`
	`83`	`+func (s *Server) init() error {`
	`84`	`+ s.initOnce.Do(s.doInit)`
	`85`	`+ return s.initErr`
	`86`	`+}`
	`87`	`+`
`74`	`88`	`func (s *Server) start() error {`
`75`	`89`	`if v, _ := strconv.ParseBool(os.Getenv("TAILSCALE_USE_WIP_CODE")); !v {`
`76`	`90`	`return errors.New("code disabled without environment variable TAILSCALE_USE_WIP_CODE set true")`
`@@ -117,11 +131,11 @@ func (s *Server) start() error {`
`117`	`131`	`return err`
`118`	`132`	`}`
`119`	`133`
`120`		`- dialer := new(tsdial.Dialer) // mutated below (before used)`
	`134`	`+ s.dialer = new(tsdial.Dialer) // mutated below (before used)`
`121`	`135`	`eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{`
`122`	`136`	`ListenPort: 0,`
`123`	`137`	`LinkMonitor: linkMon,`
`124`		`- Dialer: dialer,`
	`138`	`+ Dialer: s.dialer,`
`125`	`139`	`})`
`126`	`140`	`if err != nil {`
`127`	`141`	`return err`
`@@ -132,7 +146,7 @@ func (s *Server) start() error {`
`132`	`146`	`return fmt.Errorf("%T is not a wgengine.InternalsGetter", eng)`
`133`	`147`	`}`
`134`	`148`
`135`		`- ns, err := netstack.Create(logf, tunDev, eng, magicConn, dialer)`
	`149`	`+ ns, err := netstack.Create(logf, tunDev, eng, magicConn, s.dialer)`
`136`	`150`	`if err != nil {`
`137`	`151`	`return fmt.Errorf("netstack.Create: %w", err)`
`138`	`152`	`}`
`@@ -141,11 +155,11 @@ func (s *Server) start() error {`
`141`	`155`	`if err := ns.Start(); err != nil {`
`142`	`156`	`return fmt.Errorf("failed to start netstack: %w", err)`
`143`	`157`	`}`
`144`		`- dialer.UseNetstackForIP = func(ip netaddr.IP) bool {`
	`158`	`+ s.dialer.UseNetstackForIP = func(ip netaddr.IP) bool {`
`145`	`159`	`_, ok := eng.PeerForIP(ip)`
`146`	`160`	`return ok`
`147`	`161`	`}`
`148`		`- dialer.NetstackDialTCP = func(ctx context.Context, dst netaddr.IPPort) (net.Conn, error) {`
	`162`	`+ s.dialer.NetstackDialTCP = func(ctx context.Context, dst netaddr.IPPort) (net.Conn, error) {`
`149`	`163`	`return ns.DialContextTCP(ctx, dst)`
`150`	`164`	`}`
`151`	`165`
`@@ -156,7 +170,7 @@ func (s *Server) start() error {`
`156`	`170`	`}`
`157`	`171`	`logid := "tslib-TODO"`
`158`	`172`
`159`		`- lb, err := ipnlocal.NewLocalBackend(logf, logid, store, dialer, eng)`
	`173`	`+ lb, err := ipnlocal.NewLocalBackend(logf, logid, store, s.dialer, eng)`
`160`	`174`	`if err != nil {`
`161`	`175`	`return fmt.Errorf("NewLocalBackend: %v", err)`
`162`	`176`	`}`
`@@ -217,15 +231,15 @@ func (s *Server) forwardTCP(c net.Conn, port uint16) {`
`217`	`231`	`}`
`218`	`232`	`}`
`219`	`233`
	`234`	`+// Listen announces only on the Tailscale network.`
`220`	`235`	`func (s *Server) Listen(network, addr string) (net.Listener, error) {`
`221`	`236`	`host, port, err := net.SplitHostPort(addr)`
`222`	`237`	`if err != nil {`
`223`	`238`	`return nil, fmt.Errorf("tsnet: %w", err)`
`224`	`239`	`}`
`225`	`240`
`226`		`- s.initOnce.Do(s.doInit)`
`227`		`- if s.initErr != nil {`
`228`		`- return nil, s.initErr`
	`241`	`+ if err := s.init(); err != nil {`
	`242`	`+ return nil, err`
`229`	`243`	`}`
`230`	`244`
`231`	`245`	`key := listenKey{network, host, port}`