refactor(tsconnect/wasm): drop the unreachable LocalAPI socket

jsIPN.localAPI serves localapi.Handler in-process through an
httptest.ResponseRecorder, so nothing ever dialled the safesocket
listener that run() opened. The other in-tree callers of
safesocket.ConnectContext do not apply either: driveimpl's
FileSystemForRemote is replaced by jsFileSystemForRemote in this build,
and logpolicy's fallback is behind version.IsWindowsGUI.

Remove the listener, and with it ipnserver, whose only remaining use was
serving that listener. ipnserver.New builds a struct and SetLocalBackend
stores a pointer, so dropping both leaves LocalBackend untouched. Two
behaviours go with it: srv.Run's deferred lb.Shutdown, which made
shutdown call lb.Shutdown twice, and its localapi.Shutdown bus
subscription, which nothing in this build emits.

safesocket's generated per-listener name existed so several IPNs could
share one runtime. Each runtime has its own Go heap and its own memconn
registry, so the fixed name never conflicted between runtimes, and there
is now at most one IPN in each. Restoring the fixed name returns
safesocket_js.go to its upstream contents.

Co-Authored-By: claude-opus-5 <noreply@anthropic.com>

cmd/tsconnect/wasm/wasm_js.go

@@ -44,7 +44,6 @@ import (
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnauth"
 	"tailscale.com/ipn/ipnlocal"
-	"tailscale.com/ipn/ipnserver"
 	"tailscale.com/ipn/localapi"
 	"tailscale.com/ipn/store/mem"
 	"tailscale.com/logpolicy"
@@ -53,7 +52,6 @@ import (
 	"tailscale.com/net/netns"
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/net/tsdial"
-	"tailscale.com/safesocket"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsd"
 	"tailscale.com/types/logid"
@@ -205,7 +203,6 @@ func newIPN(jsConfig js.Value, shutdownCh chan struct{}) (map[string]any, error)
 	// initDriveForRemote must be called before NewLocalBackend (SubSystem is set-once).
 	driveFS := initDriveForRemote(sys)
 
-	srv := ipnserver.New(logf, logid, sys.Bus.Get(), sys.NetMon.Get())
 	lb, err := ipnlocal.NewLocalBackend(logf, logid, sys, controlclient.LoginEphemeral)
 	if err != nil {
 		return nil, fmt.Errorf("ipnlocal.NewLocalBackend: %w", err)
@@ -214,11 +211,9 @@ func newIPN(jsConfig js.Value, shutdownCh chan struct{}) (map[string]any, error)
 		return nil, fmt.Errorf("starting netstack: %w", err)
 	}
 	wireTaildropFileOps(lb, jsConfig.Get("fileOps"))
-	srv.SetLocalBackend(lb)
 
 	jsIPN := &jsIPN{
 		dialer:      dialer,
-		srv:         srv,
 		lb:          lb,
 		ns:          ns,
 		controlURL:  controlURL,
@@ -411,7 +406,6 @@ func newIPN(jsConfig js.Value, shutdownCh chan struct{}) (map[string]any, error)
 
 type jsIPN struct {
 	dialer     *tsdial.Dialer
-	srv        *ipnserver.Server
 	lb         *ipnlocal.LocalBackend
 	ns         *netstack.Impl
 	controlURL string
@@ -422,9 +416,6 @@ type jsIPN struct {
 	funnelMu    sync.Mutex
 	funnelPorts map[uint16]*funnelListenerEntry
 
-	// ln is the safesocket listener created by run(); stored here so shutdown
-	// can close it and unblock srv.Run.
-	ln           net.Listener
 	shutdownCh   chan struct{} // closed by shutdown() to unblock main()
 	shutdownOnce sync.Once
 }
@@ -617,18 +608,6 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 		}
 	}()
 
-	ln, err := safesocket.Listen("")
-	if err != nil {
-		log.Fatalf("safesocket.Listen: %v", err)
-	}
-	i.ln = ln
-
-	go func() {
-		err := i.srv.Run(context.Background(), ln)
-		if err != nil && !errors.Is(err, net.ErrClosed) {
-			log.Fatalf("ipnserver.Run exited: %v", err)
-		}
-	}()
 }
 
 func (i *jsIPN) login() {
@@ -652,9 +631,6 @@ func (i *jsIPN) shutdown() js.Value {
 			if i.lb != nil {
 				i.lb.Shutdown()
 			}
-			if i.ln != nil {
-				i.ln.Close()
-			}
 			close(i.shutdownCh)
 		})
 		return nil, nil

safesocket/safesocket_js.go

@@ -5,22 +5,15 @@ package safesocket
 
 import (
 	"context"
-	"fmt"
 	"net"
-	"sync/atomic"
 
 	"github.com/akutz/memconn"
 )
 
 const memName = "Tailscale-IPN"
 
-// memSeq ensures each IPN instance in the same WASM process gets a distinct
-// memconn address, so concurrent instances do not conflict on the registry.
-var memSeq atomic.Int64
-
 func listen(path string) (net.Listener, error) {
-	name := fmt.Sprintf("%s-%d", memName, memSeq.Add(1))
-	return memconn.Listen("memu", name)
+	return memconn.Listen("memu", memName)
 }
 
 func connect(ctx context.Context, _ string) (net.Conn, error) {