net/tsdial: also plumb TUN name and monitor into tsdial.Dialer

In prep for moving stuff out of LocalBackend.

Change-Id: I9725aa9c3ebc7275f8c40e040b326483c0340127
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/tailscaled/tailscaled.go

@@ -308,6 +308,8 @@ func run() error {
 	socksListener, httpProxyListener := mustStartProxyListeners(args.socksAddr, args.httpProxyAddr)
 
 	dialer := new(tsdial.Dialer) // mutated below (before used)
+	dialer.SetLinkMonitor(linkMon)
+
 	e, useNetstack, err := createEngine(logf, linkMon, dialer)
 	if err != nil {
 		logf("wgengine.New: %v", err)

cmd/tailscaled/tailscaled_windows.go

@@ -39,6 +39,7 @@
 	"tailscale.com/version"
 	"tailscale.com/wf"
 	"tailscale.com/wgengine"
+	"tailscale.com/wgengine/monitor"
 	"tailscale.com/wgengine/netstack"
 	"tailscale.com/wgengine/router"
 )
@@ -177,6 +178,11 @@ func beFirewallKillswitch() bool {
 func startIPNServer(ctx context.Context, logid string) error {
 	var logf logger.Logf = log.Printf
 
+	linkMon, err := monitor.New(logf)
+	if err != nil {
+		return err
+	}
+
 	getEngineRaw := func() (wgengine.Engine, error) {
 		dev, devName, err := tstun.New(logf, "Tailscale")
 		if err != nil {
@@ -197,10 +203,11 @@ func startIPNServer(ctx context.Context, logid string) error {
 			return nil, fmt.Errorf("DNS: %w", err)
 		}
 		eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
-			Tun:        dev,
-			Router:     r,
-			DNS:        d,
-			ListenPort: 41641,
+			Tun:         dev,
+			Router:      r,
+			DNS:         d,
+			ListenPort:  41641,
+			LinkMonitor: linkMon,
 		})
 		if err != nil {
 			r.Close()
@@ -287,7 +294,7 @@ type engineOrError struct {
 		return fmt.Errorf("safesocket.Listen: %v", err)
 	}
 
-	err = ipnserver.Run(ctx, logf, ln, store, logid, getEngine, ipnServerOpts())
+	err = ipnserver.Run(ctx, logf, ln, store, linkMon, logid, getEngine, ipnServerOpts())
 	if err != nil {
 		logf("ipnserver.Run: %v", err)
 	}

ipn/ipnlocal/local.go

@@ -2185,17 +2185,9 @@ func (b *LocalBackend) initPeerAPIListener() {
 		return
 	}
 
-	var tunName string
-	if ge, ok := b.e.(wgengine.InternalsGetter); ok {
-		if tunWrap, _, ok := ge.GetInternals(); ok {
-			tunName, _ = tunWrap.Name()
-		}
-	}
-
 	ps := &peerAPIServer{
 		b:              b,
 		rootDir:        fileRoot,
-		tunName:        tunName,
 		selfNode:       selfNode,
 		directFileMode: b.directFileRoot != "",
 	}

ipn/ipnlocal/peerapi.go

@@ -49,7 +49,6 @@
 type peerAPIServer struct {
 	b          *LocalBackend
 	rootDir    string
-	tunName    string
 	selfNode   *tailcfg.Node
 	knownEmpty syncs.AtomicBool
 	resolver   *resolver.Resolver
@@ -363,7 +362,7 @@ func (s *peerAPIServer) listen(ip netaddr.IP, ifState *interfaces.State) (ln net
 		// On iOS/macOS, this sets the lc.Control hook to
 		// setsockopt the interface index to bind to, to get
 		// out of the network sandbox.
-		if err := initListenConfig(&lc, ip, ifState, s.tunName); err != nil {
+		if err := initListenConfig(&lc, ip, ifState, s.b.dialer.TUNName()); err != nil {
 			return nil, err
 		}
 		if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {

ipn/ipnserver/server.go

@@ -50,6 +50,7 @@
 	"tailscale.com/version"
 	"tailscale.com/version/distro"
 	"tailscale.com/wgengine"
+	"tailscale.com/wgengine/monitor"
 )
 
 // Options is the configuration of the Tailscale node agent.
@@ -653,7 +654,7 @@ func StateStore(path string, logf logger.Logf) (ipn.StateStore, error) {
 // The getEngine func is called repeatedly, once per connection, until it returns an engine successfully.
 //
 // Deprecated: use New and Server.Run instead.
-func Run(ctx context.Context, logf logger.Logf, ln net.Listener, store ipn.StateStore, logid string, getEngine func() (wgengine.Engine, error), opts Options) error {
+func Run(ctx context.Context, logf logger.Logf, ln net.Listener, store ipn.StateStore, linkMon *monitor.Mon, logid string, getEngine func() (wgengine.Engine, error), opts Options) error {
 	getEngine = getEngineUntilItWorksWrapper(getEngine)
 	runDone := make(chan struct{})
 	defer close(runDone)
@@ -738,6 +739,7 @@ func Run(ctx context.Context, logf logger.Logf, ln net.Listener, store ipn.State
 	}
 
 	dialer := new(tsdial.Dialer)
+	dialer.SetLinkMonitor(linkMon)
 	eng.AddNetworkMapCallback(func(nm *netmap.NetworkMap) {
 		dialer.SetDNSMap(tsdial.DNSMapFromNetworkMap(nm))
 	})

ipn/ipnserver/server_test.go

@@ -72,6 +72,6 @@ func TestRunMultipleAccepts(t *testing.T) {
 	}
 	defer ln.Close()
 
-	err = ipnserver.Run(ctx, logTriggerTestf, ln, store, "dummy_logid", ipnserver.FixedEngine(eng), opts)
+	err = ipnserver.Run(ctx, logTriggerTestf, ln, store, nil /* mon */, "dummy_logid", ipnserver.FixedEngine(eng), opts)
 	t.Logf("ipnserver.Run = %v", err)
 }

net/tsdial/tsdial.go

@@ -17,6 +17,7 @@
 
 	"inet.af/netaddr"
 	"tailscale.com/net/netknob"
+	"tailscale.com/wgengine/monitor"
 )
 
 // Dialer dials out of tailscaled, while taking care of details while
@@ -37,8 +38,33 @@ type Dialer struct {
 	peerClientOnce sync.Once
 	peerClient     *http.Client
 
-	mu  sync.Mutex
-	dns DNSMap
+	mu      sync.Mutex
+	dns     DNSMap
+	tunName string // tun device name
+	linkMon *monitor.Mon
+}
+
+// SetTUNName sets the name of the tun device in use ("tailscale0", "utun6",
+// etc). This is needed on some platforms to set sockopts to bind
+// to the same interface index.
+func (d *Dialer) SetTUNName(name string) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.tunName = name
+}
+
+// TUNName returns the name of the tun device in use, if any.
+// Example format ("tailscale0", "utun6").
+func (d *Dialer) TUNName() string {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	return d.tunName
+}
+
+func (d *Dialer) SetLinkMonitor(mon *monitor.Mon) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.linkMon = mon
 }
 
 // PeerDialControlFunc returns a function

wgengine/userspace.go

@@ -318,6 +318,7 @@ func NewUserspaceEngine(logf logger.Logf, conf Config) (_ Engine, reterr error)
 	}
 
 	tunName, _ := conf.Tun.Name()
+	conf.Dialer.SetTUNName(tunName)
 	e.dns = dns.NewManager(logf, conf.DNS, e.linkMon, conf.Dialer, fwdDNSLinkSelector{e, tunName})
 
 	logf("link state: %+v", e.linkMon.InterfaceState())