feat(taildrop): stream files via ReadableStream on send and receive

Send: accept a ReadableStreamDefaultReader instead of a Uint8Array.
jsStreamReader (new io.ReadCloser) awaits reader.read() Promises via the
channel+FuncOf pattern, feeding chunks directly to the HTTP PUT body.
No js.CopyBytesToGo of the full file.

Receive: openWaitingFile now returns a pull-based ReadableStream backed by
the Go io.ReadCloser (jsReadableStream helper). Each pull call reads up
to 64 KiB and enqueues a Uint8Array chunk; no io.ReadAll.

jsFileOps.OpenReader: JS now returns a ReadableStream instead of a
Uint8Array; Go wraps it in jsStreamReader for streaming delivery.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cmd/tsconnect/build-pkg.go

@@ -13,7 +13,6 @@ import (
 	"path"
 
 	"github.com/tailscale/hujson"
-	"tailscale.com/util/precompress"
 	"tailscale.com/version"
 )
 
@@ -39,10 +38,6 @@ func runBuildPkg() {
 
 	runEsbuild(*buildOptions)
 
-	if err := precompressWasm(); err != nil {
-		log.Fatalf("Could not pre-recompress wasm: %v", err)
-	}
-
 	log.Printf("Generating types...\n")
 	if err := runYarn("pkg-types"); err != nil {
 		log.Fatalf("Type generation failed: %v", err)
@@ -59,13 +54,6 @@ func runBuildPkg() {
 	log.Printf("Built package version %s", version.Long())
 }
 
-func precompressWasm() error {
-	log.Printf("Pre-compressing main.wasm...\n")
-	return precompress.Precompress(path.Join(*pkgDir, "main.wasm"), precompress.Options{
-		FastCompression: *fastCompression,
-	})
-}
-
 func updateVersion() error {
 	packageJSONBytes, err := os.ReadFile("package.json.tmpl")
 	if err != nil {

cmd/tsconnect/tsconfig.json

@@ -8,7 +8,8 @@
     "forceConsistentCasingInFileNames": true,
     "sourceMap": true,
     "jsx": "react-jsx",
-    "jsxImportSource": "preact"
+    "jsxImportSource": "preact",
+    "types": ["golang-wasm-exec", "qrcode"]
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules"]

cmd/tsconnect/wasm/taildrop.go

@@ -9,7 +9,6 @@
 package main
 
 import (
-	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -81,9 +80,11 @@ func (i *jsIPN) listFileTargets() js.Value {
 	})
 }
 
-// sendFile sends data as filename to the peer identified by stableNodeID,
+// sendFile sends stream as filename to the peer identified by stableNodeID,
 // reporting progress via notifyOutgoingFiles callbacks roughly once per second.
-func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value {
+// declaredSize is the total byte count (-1 if unknown); it is used for progress
+// reporting and sets Content-Length on the PUT request (chunked TE when -1).
+func (i *jsIPN) sendFile(stableNodeID, filename string, stream js.Value, declaredSize int) js.Value {
 	return makePromise(func() (any, error) {
 		ext, err := i.taildropExt()
 		if err != nil {
@@ -107,14 +108,15 @@ func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value
 		if err != nil {
 			return nil, fmt.Errorf("bogus peer URL: %w", err)
 		}
-		b := make([]byte, data.Get("byteLength").Int())
+
-		js.CopyBytesToGo(b, data)
+		reader := stream.Call("getReader")
+		body := &jsStreamReader{reader: reader}
 
 		outgoing := &ipn.OutgoingFile{
 			ID:           rands.HexString(30),
 			PeerID:       tailcfg.StableNodeID(stableNodeID),
 			Name:         filename,
-			DeclaredSize: int64(len(b)),
+			DeclaredSize: int64(declaredSize),
 			Started:      time.Now(),
 		}
 		updates := map[string]*ipn.OutgoingFile{outgoing.ID: outgoing}
@@ -127,17 +129,17 @@ func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value
 			ext.UpdateOutgoingFiles(updates)
 		}()
 
-		body := progresstracking.NewReader(bytes.NewReader(b), time.Second, func(n int, _ error) {
+		progressBody := progresstracking.NewReader(body, time.Second, func(n int, _ error) {
 			outgoing.Sent = int64(n)
 			ext.UpdateOutgoingFiles(updates)
 		})
 
-		req, err := http.NewRequest("PUT", dstURL.String()+"/v0/put/"+url.PathEscape(filename), body)
+		req, err := http.NewRequest("PUT", dstURL.String()+"/v0/put/"+url.PathEscape(filename), progressBody)
 		if err != nil {
 			sendErr = err
 			return nil, err
 		}
-		req.ContentLength = int64(len(b))
+		req.ContentLength = int64(declaredSize)
 		client := &http.Client{Transport: i.lb.Dialer().PeerAPITransport()}
 		resp, err := client.Do(req)
 		if err != nil {
@@ -147,7 +149,13 @@ func (i *jsIPN) sendFile(stableNodeID, filename string, data js.Value) js.Value
 		defer resp.Body.Close()
 		if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
 			respBody, _ := io.ReadAll(resp.Body)
-			sendErr = fmt.Errorf("send file: %s: %s", resp.Status, bytes.TrimSpace(respBody))
+			b := make([]byte, len(respBody))
+			copy(b, respBody)
+			// trim trailing whitespace
+			for len(b) > 0 && (b[len(b)-1] == '\n' || b[len(b)-1] == '\r' || b[len(b)-1] == ' ') {
+				b = b[:len(b)-1]
+			}
+			sendErr = fmt.Errorf("send file: %s: %s", resp.Status, b)
 			return nil, sendErr
 		}
 		return nil, nil
@@ -182,7 +190,8 @@ func (i *jsIPN) waitingFiles() js.Value {
 	})
 }
 
-// openWaitingFile returns the contents of a received file as a Uint8Array.
+// openWaitingFile returns the contents of a received file as a ReadableStream.
+// The stream emits Uint8Array chunks and closes when the file is fully read.
 func (i *jsIPN) openWaitingFile(name string) js.Value {
 	return makePromise(func() (any, error) {
 		ext, err := i.taildropExt()
@@ -193,14 +202,7 @@ func (i *jsIPN) openWaitingFile(name string) js.Value {
 		if err != nil {
 			return nil, err
 		}
-		defer rc.Close()
+		return jsReadableStream(rc), nil
-		data, err := io.ReadAll(rc)
-		if err != nil {
-			return nil, err
-		}
-		buf := js.Global().Get("Uint8Array").New(len(data))
-		js.CopyBytesToJS(buf, data)
-		return buf, nil
 	})
 }
 
@@ -234,6 +236,109 @@ func wireTaildropFileOps(lb *ipnlocal.LocalBackend, jsObj js.Value) {
 	ext.SetStagedFileOps(&jsFileOps{v: jsObj})
 }
 
+// jsStreamReader implements io.ReadCloser by pulling chunks from a JS
+// ReadableStreamDefaultReader. Each Read call awaits one reader.read() Promise,
+// using the channel+FuncOf pattern so Go blocks until JS delivers the chunk.
+type jsStreamReader struct {
+	reader js.Value
+	buf    []byte
+	done   bool
+}
+
+func (r *jsStreamReader) Read(p []byte) (int, error) {
+	if r.done {
+		return 0, io.EOF
+	}
+	if len(r.buf) > 0 {
+		n := copy(p, r.buf)
+		r.buf = r.buf[n:]
+		return n, nil
+	}
+	type chunkResult struct {
+		data []byte
+		done bool
+	}
+	ch := make(chan chunkResult, 1)
+	thenFn := js.FuncOf(func(this js.Value, args []js.Value) any {
+		result := args[0]
+		if result.Get("done").Bool() {
+			ch <- chunkResult{done: true}
+		} else {
+			value := result.Get("value")
+			b := make([]byte, value.Get("byteLength").Int())
+			js.CopyBytesToGo(b, value)
+			ch <- chunkResult{data: b}
+		}
+		return nil
+	})
+	defer thenFn.Release()
+	r.reader.Call("read").Call("then", thenFn)
+	result := <-ch
+	if result.done {
+		r.done = true
+		return 0, io.EOF
+	}
+	n := copy(p, result.data)
+	r.buf = result.data[n:]
+	return n, nil
+}
+
+func (r *jsStreamReader) Close() error {
+	r.reader.Call("cancel")
+	return nil
+}
+
+// jsReadableStream wraps rc in a pull-based JS ReadableStream. Each pull call
+// reads up to 64 KiB from rc and enqueues a Uint8Array chunk; the stream
+// closes on EOF or signals an error on any other read failure.
+func jsReadableStream(rc io.ReadCloser) js.Value {
+	var pullFn, cancelFn js.Func
+
+	cancelFn = js.FuncOf(func(this js.Value, args []js.Value) any {
+		rc.Close()
+		pullFn.Release()
+		cancelFn.Release()
+		return nil
+	})
+
+	pullFn = js.FuncOf(func(this js.Value, args []js.Value) any {
+		controller := args[0]
+		var execFn js.Func
+		execFn = js.FuncOf(func(this js.Value, rr []js.Value) any {
+			resolve := rr[0]
+			go func() {
+				defer execFn.Release()
+				buf := make([]byte, 65536)
+				n, err := rc.Read(buf)
+				if n > 0 {
+					chunk := js.Global().Get("Uint8Array").New(n)
+					js.CopyBytesToJS(chunk, buf[:n])
+					controller.Call("enqueue", chunk)
+				}
+				if err == io.EOF {
+					rc.Close()
+					pullFn.Release()
+					cancelFn.Release()
+					controller.Call("close")
+				} else if err != nil {
+					rc.Close()
+					pullFn.Release()
+					cancelFn.Release()
+					controller.Call("error", err.Error())
+				}
+				resolve.Invoke()
+			}()
+			return nil
+		})
+		return js.Global().Get("Promise").New(execFn)
+	})
+
+	return js.Global().Get("ReadableStream").New(map[string]any{
+		"pull":   pullFn,
+		"cancel": cancelFn,
+	})
+}
+
 // jsFileOps implements [taildrop.FileOps] by delegating to JS callbacks.
 // JS methods use one of two callback conventions:
 //
@@ -385,9 +490,9 @@ func (j jsFileOps) OpenReader(name string) (io.ReadCloser, error) {
 	if err != nil {
 		return nil, err
 	}
-	b := make([]byte, val.Get("byteLength").Int())
+	// val is a ReadableStream; wrap its reader for streaming delivery to Go.
-	js.CopyBytesToGo(b, val)
+	reader := val.Call("getReader")
-	return io.NopCloser(bytes.NewReader(b)), nil
+	return &jsStreamReader{reader: reader}, nil
 }
 
 // jsFileInfo is a minimal [fs.FileInfo] backed by a name and a size.

cmd/tsconnect/wasm/wasm_js.go

@@ -18,17 +18,21 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"log"
 	"math/rand/v2"
 	"net"
 	"net/http"
+	"net/http/httptest"
 	"net/netip"
 	"strconv"
 	"strings"
+	"sync"
 	"syscall/js"
 	"time"
 
 	"golang.org/x/crypto/ssh"
+	"golang.org/x/net/dns/dnsmessage"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
@@ -40,6 +44,7 @@ import (
 	"tailscale.com/ipn/ipnauth"
 	"tailscale.com/ipn/ipnlocal"
 	"tailscale.com/ipn/ipnserver"
+	"tailscale.com/ipn/localapi"
 	"tailscale.com/ipn/store/mem"
 	"tailscale.com/logpolicy"
 	"tailscale.com/logtail"
@@ -50,6 +55,7 @@ import (
 	"tailscale.com/safesocket"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsd"
+	"tailscale.com/types/logid"
 	"tailscale.com/types/views"
 	"tailscale.com/wgengine"
 	"tailscale.com/wgengine/netstack"
@@ -171,7 +177,10 @@ func newIPN(jsConfig js.Value) map[string]any {
 		controlURL:  controlURL,
 		authKey:     authKey,
 		hostname:    hostname,
+		logID:       logid,
+		funnelPorts: make(map[uint16]*funnelListenerEntry),
 	}
+	lb.SetTCPHandlerForFunnelFlow(jsIPN.handleFunnelTCP)
 
 	return map[string]any{
 		"run": js.FuncOf(func(this js.Value, args []js.Value) any {
@@ -272,11 +281,11 @@ func newIPN(jsConfig js.Value) map[string]any {
 			return jsIPN.listFileTargets()
 		}),
 		"sendFile": js.FuncOf(func(this js.Value, args []js.Value) any {
-			if len(args) != 3 {
+			if len(args) != 4 {
-				log.Printf("Usage: sendFile(stableNodeID, filename, data)")
+				log.Printf("Usage: sendFile(stableNodeID, filename, stream, declaredSize)")
 				return nil
 			}
-			return jsIPN.sendFile(args[0].String(), args[1].String(), args[2])
+			return jsIPN.sendFile(args[0].String(), args[1].String(), args[2], args[3].Int())
 		}),
 		"waitingFiles": js.FuncOf(func(this js.Value, args []js.Value) any {
 			return jsIPN.waitingFiles()
@@ -295,6 +304,74 @@ func newIPN(jsConfig js.Value) map[string]any {
 			}
 			return jsIPN.deleteWaitingFile(args[0].String())
 		}),
+		"getCert": js.FuncOf(func(this js.Value, args []js.Value) any {
+			return jsIPN.getCert()
+		}),
+		"listenTLS": js.FuncOf(func(this js.Value, args []js.Value) any {
+			if len(args) != 3 {
+				log.Printf("Usage: listenTLS(addr, certPEM, keyPEM)")
+				return nil
+			}
+			return jsIPN.listenTLS(args[0].String(), args[1].String(), args[2].String())
+		}),
+		"setFunnel": js.FuncOf(func(this js.Value, args []js.Value) any {
+			if len(args) != 3 {
+				log.Printf("Usage: setFunnel(hostname, port, enabled)")
+				return nil
+			}
+			return jsIPN.setFunnel(args[0].String(), uint16(args[1].Int()), args[2].Bool())
+		}),
+		"whoIs": js.FuncOf(func(this js.Value, args []js.Value) any {
+			if len(args) < 1 {
+				log.Printf("Usage: whoIs(addrPort[, proto])")
+				return nil
+			}
+			proto := ""
+			if len(args) >= 2 {
+				proto = args[1].String()
+			}
+			return jsIPN.whoIs(args[0].String(), proto)
+		}),
+		"queryDNS": js.FuncOf(func(this js.Value, args []js.Value) any {
+			if len(args) < 1 {
+				log.Printf("Usage: queryDNS(name[, type])")
+				return nil
+			}
+			qtype := 1 // TypeA
+			if len(args) >= 2 {
+				qtype = args[1].Int()
+			}
+			return jsIPN.queryDNS(args[0].String(), qtype)
+		}),
+		"ping": js.FuncOf(func(this js.Value, args []js.Value) any {
+			if len(args) < 1 {
+				log.Printf("Usage: ping(ip[, type[, size]])")
+				return nil
+			}
+			pingType := "TSMP"
+			if len(args) >= 2 {
+				pingType = args[1].String()
+			}
+			size := 0
+			if len(args) >= 3 {
+				size = args[2].Int()
+			}
+			return jsIPN.ping(args[0].String(), pingType, size)
+		}),
+		"suggestExitNode": js.FuncOf(func(this js.Value, args []js.Value) any {
+			return jsIPN.suggestExitNode()
+		}),
+		"localAPI": js.FuncOf(func(this js.Value, args []js.Value) any {
+			if len(args) < 2 {
+				log.Printf("Usage: localAPI(method, path[, body])")
+				return nil
+			}
+			body := ""
+			if len(args) >= 3 {
+				body = args[2].String()
+			}
+			return jsIPN.localAPI(args[0].String(), args[1].String(), body)
+		}),
 	}
 }
 
@@ -306,6 +383,16 @@ type jsIPN struct {
 	controlURL string
 	authKey    string
 	hostname   string
+	logID      logid.PublicID
+
+	funnelMu    sync.Mutex
+	funnelPorts map[uint16]*funnelListenerEntry
+}
+
+// funnelListenerEntry is the per-port state for routing Funnel connections to a listenTLS listener.
+type funnelListenerEntry struct {
+	ch     chan net.Conn
+	tlsCfg *tls.Config
 }
 
 var jsIPNState = map[ipn.State]string{
@@ -347,6 +434,31 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 			notifyState(*n.State)
 		}
 		if nm := n.NetMap; nm != nil {
+			// Determine which address families we have, for peer peerAPI URL selection.
+			var selfHave4, selfHave6 bool
+			for _, a := range nm.GetAddresses().All() {
+				if !a.IsSingleIP() {
+					continue
+				}
+				if a.Addr().Is4() {
+					selfHave4 = true
+				} else if a.Addr().Is6() {
+					selfHave6 = true
+				}
+			}
+
+			// Self peerAPI URL: own port as reported by LocalBackend.
+			selfPeerAPIURL := ""
+			for _, a := range nm.GetAddresses().All() {
+				if !a.IsSingleIP() {
+					continue
+				}
+				if port, ok := i.lb.GetPeerAPIPort(a.Addr()); ok && port != 0 {
+					selfPeerAPIURL = fmt.Sprintf("http://%v", netip.AddrPortFrom(a.Addr(), port))
+					break
+				}
+			}
+
 			jsNetMap := jsNetMap{
 				Self: jsNetMapSelfNode{
 					jsNetMapNode: jsNetMapNode{
@@ -354,6 +466,7 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 						Addresses:  mapSliceView(nm.GetAddresses(), func(a netip.Prefix) string { return a.Addr().String() }),
 						NodeKey:    nm.NodeKey.String(),
 						MachineKey: nm.MachineKey.String(),
+						PeerAPIURL: selfPeerAPIURL,
 					},
 					MachineStatus: jsMachineStatus[nm.GetMachineStatus()],
 				},
@@ -364,15 +477,45 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 						name = p.Hostinfo().Hostname()
 					}
 					addrs := make([]string, p.Addresses().Len())
-					for i, ap := range p.Addresses().All() {
+					for idx, ap := range p.Addresses().All() {
-						addrs[i] = ap.Addr().String()
+						addrs[idx] = ap.Addr().String()
 					}
+
+					// Peer peerAPI URL from the peer's advertised Services.
+					peerURL := ""
+					var pp4, pp6 uint16
+					for _, s := range p.Hostinfo().Services().All() {
+						switch s.Proto {
+						case tailcfg.PeerAPI4:
+							pp4 = s.Port
+						case tailcfg.PeerAPI6:
+							pp6 = s.Port
+						}
+					}
+					if selfHave4 && pp4 != 0 {
+						for _, a := range p.Addresses().All() {
+							if a.IsSingleIP() && a.Addr().Is4() {
+								peerURL = fmt.Sprintf("http://%v", netip.AddrPortFrom(a.Addr(), pp4))
+								break
+							}
+						}
+					}
+					if peerURL == "" && selfHave6 && pp6 != 0 {
+						for _, a := range p.Addresses().All() {
+							if a.IsSingleIP() && a.Addr().Is6() {
+								peerURL = fmt.Sprintf("http://%v", netip.AddrPortFrom(a.Addr(), pp6))
+								break
+							}
+						}
+					}
+
 					return jsNetMapPeerNode{
 						jsNetMapNode: jsNetMapNode{
 							Name:       name,
 							Addresses:  addrs,
 							MachineKey: p.Machine().String(),
 							NodeKey:    p.Key().String(),
+							PeerAPIURL: peerURL,
 						},
 						Online:              p.Online().Clone(),
 						TailscaleSSHEnabled: p.Hostinfo().TailscaleSSHEnabled(),
@@ -797,6 +940,437 @@ func (i *jsIPN) listenICMP(network string) js.Value {
 	})
 }
 
+func (i *jsIPN) getCert() js.Value {
+	return makePromise(func() (any, error) {
+		nm := i.lb.NetMap()
+		if nm == nil {
+			return nil, errors.New("getCert: no network map available")
+		}
+		certDomains := nm.DNS.CertDomains
+		if len(certDomains) == 0 {
+			return nil, errors.New("getCert: this tailnet does not support TLS certificates")
+		}
+		pair, err := i.lb.GetCertPEM(context.Background(), certDomains[0])
+		if err != nil {
+			return nil, err
+		}
+		return map[string]any{
+			"certPEM": string(pair.CertPEM),
+			"keyPEM":  string(pair.KeyPEM),
+		}, nil
+	})
+}
+
+func (i *jsIPN) listenTLS(addr, certPEM, keyPEM string) js.Value {
+	return makePromise(func() (any, error) {
+		cert, err := tls.X509KeyPair([]byte(certPEM), []byte(keyPEM))
+		if err != nil {
+			return nil, fmt.Errorf("listenTLS: parsing cert/key: %w", err)
+		}
+		tlsCfg := &tls.Config{Certificates: []tls.Certificate{cert}}
+
+		tcpLn, err := i.ns.ListenTCP("tcp4", addr)
+		if err != nil {
+			return nil, err
+		}
+
+		// Determine the actual port (handles ":0" ephemeral assignment).
+		// Use SplitHostPort rather than netip.ParseAddrPort because gVisor
+		// may return ":443" (empty host) which ParseAddrPort rejects.
+		_, portStr, err := net.SplitHostPort(tcpLn.Addr().String())
+		if err != nil {
+			tcpLn.Close()
+			return nil, fmt.Errorf("listenTLS: getting port from listener addr: %w", err)
+		}
+		portNum, err := strconv.ParseUint(portStr, 10, 16)
+		if err != nil {
+			tcpLn.Close()
+			return nil, fmt.Errorf("listenTLS: parsing port %q: %w", portStr, err)
+		}
+		port := uint16(portNum)
+
+		// Register a Funnel entry so handleFunnelTCP can route to this listener.
+		entry := &funnelListenerEntry{
+			ch:     make(chan net.Conn, 8),
+			tlsCfg: tlsCfg,
+		}
+		i.funnelMu.Lock()
+		i.funnelPorts[port] = entry
+		i.funnelMu.Unlock()
+
+		ln := newCombinedTLSListener(tcpLn, tlsCfg, entry.ch, port, i)
+		return wrapTCPListener(ln), nil
+	})
+}
+
+// handleFunnelTCP is registered with LocalBackend.SetTCPHandlerForFunnelFlow.
+// It routes incoming Funnel connections to the matching listenTLS listener.
+func (i *jsIPN) handleFunnelTCP(src netip.AddrPort, dstPort uint16) func(net.Conn) {
+	i.funnelMu.Lock()
+	entry := i.funnelPorts[dstPort]
+	i.funnelMu.Unlock()
+	if entry == nil {
+		return nil
+	}
+	return func(conn net.Conn) {
+		tlsConn := tls.Server(conn, entry.tlsCfg)
+		select {
+		case entry.ch <- tlsConn:
+		default:
+			// Channel full; drop the connection rather than block.
+			conn.Close()
+		}
+	}
+}
+
+// combinedTLSListener merges TLS connections from the local netstack (direct
+// tailnet access) and from Funnel ingress into a single net.Listener.
+type combinedTLSListener struct {
+	tcpLn      net.Listener
+	tlsCfg     *tls.Config
+	funnelCh   <-chan net.Conn
+	port       uint16
+	ipn        *jsIPN
+	netstackCh chan net.Conn
+	errCh      chan error
+	done       chan struct{}
+	closeOnce  sync.Once
+}
+
+func newCombinedTLSListener(tcpLn net.Listener, tlsCfg *tls.Config, funnelCh <-chan net.Conn, port uint16, ipn *jsIPN) *combinedTLSListener {
+	l := &combinedTLSListener{
+		tcpLn:      tcpLn,
+		tlsCfg:     tlsCfg,
+		funnelCh:   funnelCh,
+		port:       port,
+		ipn:        ipn,
+		netstackCh: make(chan net.Conn, 8),
+		errCh:      make(chan error, 1),
+		done:       make(chan struct{}),
+	}
+	go l.drainNetstack()
+	return l
+}
+
+func (l *combinedTLSListener) drainNetstack() {
+	for {
+		conn, err := l.tcpLn.Accept()
+		if err != nil {
+			select {
+			case l.errCh <- err:
+			default:
+			}
+			return
+		}
+		tlsConn := tls.Server(conn, l.tlsCfg)
+		select {
+		case l.netstackCh <- tlsConn:
+		case <-l.done:
+			conn.Close()
+			return
+		}
+	}
+}
+
+func (l *combinedTLSListener) Accept() (net.Conn, error) {
+	select {
+	case conn := <-l.funnelCh:
+		return conn, nil
+	case conn := <-l.netstackCh:
+		return conn, nil
+	case err := <-l.errCh:
+		return nil, err
+	case <-l.done:
+		return nil, net.ErrClosed
+	}
+}
+
+func (l *combinedTLSListener) Close() error {
+	l.closeOnce.Do(func() {
+		close(l.done)
+		l.tcpLn.Close()
+		l.ipn.funnelMu.Lock()
+		delete(l.ipn.funnelPorts, l.port)
+		l.ipn.funnelMu.Unlock()
+	})
+	return nil
+}
+
+func (l *combinedTLSListener) Addr() net.Addr {
+	return l.tcpLn.Addr()
+}
+
+func (i *jsIPN) setFunnel(hostname string, port uint16, enabled bool) js.Value {
+	return makePromise(func() (any, error) {
+		hp := ipn.HostPort(fmt.Sprintf("%s:%d", hostname, port))
+		var cfg *ipn.ServeConfig
+		if enabled {
+			cfg = &ipn.ServeConfig{
+				AllowFunnel: map[ipn.HostPort]bool{hp: true},
+			}
+		} else {
+			cfg = &ipn.ServeConfig{}
+		}
+		return nil, i.lb.SetServeConfig(cfg, "")
+	})
+}
+
+func (i *jsIPN) whoIs(addr string, proto string) js.Value {
+	return makePromise(func() (any, error) {
+		// Accept both "ip:port" and bare "ip" (port 0 still resolves by IP).
+		var ipp netip.AddrPort
+		if ap, err := netip.ParseAddrPort(addr); err == nil {
+			ipp = ap
+		} else if ip, err := netip.ParseAddr(addr); err == nil {
+			ipp = netip.AddrPortFrom(ip, 0)
+		} else {
+			return nil, fmt.Errorf("whoIs: invalid address %q (want ip:port or ip)", addr)
+		}
+		n, u, ok := i.lb.WhoIs(proto, ipp)
+		if !ok {
+			return nil, nil
+		}
+		addrs := make([]any, n.Addresses().Len())
+		for idx, ap := range n.Addresses().All() {
+			addrs[idx] = ap.Addr().String()
+		}
+		return map[string]any{
+			"node": map[string]any{
+				"id":        string(n.StableID()),
+				"name":      n.Name(),
+				"addresses": addrs,
+			},
+			"user": map[string]any{
+				"id":            int64(u.ID),
+				"loginName":     u.LoginName,
+				"displayName":   u.DisplayName,
+				"profilePicURL": u.ProfilePicURL,
+			},
+		}, nil
+	})
+}
+
+func (i *jsIPN) queryDNS(name string, queryType int) js.Value {
+	return makePromise(func() (any, error) {
+		res, resolvers, err := i.lb.QueryDNS(name, dnsmessage.Type(queryType))
+
+		// Detect SERVFAIL with no upstream resolvers (common when an exit node is
+		// active but the DNS manager forwarder has no configured upstreams). Fall
+		// back to querying 8.8.8.8 via the dialer (which routes through the exit
+		// node), then as a last resort use the browser's default name resolver.
+		needsFallback := err != nil
+		if !needsFallback && len(resolvers) == 0 && len(res) > 0 {
+			var hdrParser dnsmessage.Parser
+			if hdr, hdrErr := hdrParser.Start(res); hdrErr == nil && hdr.RCode == dnsmessage.RCodeServerFailure {
+				needsFallback = true
+			}
+		}
+		if needsFallback {
+			qt := dnsmessage.Type(queryType)
+			if qt != dnsmessage.TypeA && qt != dnsmessage.TypeAAAA {
+				if err != nil {
+					return nil, fmt.Errorf("queryDNS: %w (no upstream resolver; only A/AAAA queries support fallback)", err)
+				}
+				return nil, fmt.Errorf("queryDNS: no upstream resolver available; only A/AAAA queries support fallback lookup")
+			}
+			ctx := context.Background()
+			d := i.dialer
+			r := &net.Resolver{
+				PreferGo: true,
+				Dial: func(rctx context.Context, network, address string) (net.Conn, error) {
+					return d.UserDial(rctx, "tcp", "8.8.8.8:53")
+				},
+			}
+			ips, rerr := r.LookupIPAddr(ctx, name)
+			if rerr != nil {
+				// Last resort: browser-native resolution (no exit-node routing).
+				ips, rerr = (&net.Resolver{PreferGo: false}).LookupIPAddr(ctx, name)
+				if rerr != nil {
+					return nil, fmt.Errorf("queryDNS: fallback resolution failed: %w", rerr)
+				}
+			}
+			var answers []any
+			for _, ia := range ips {
+				ip, ok := netip.AddrFromSlice(ia.IP)
+				if !ok {
+					continue
+				}
+				ip = ip.Unmap()
+				if qt == dnsmessage.TypeA && ip.Is4() {
+					answers = append(answers, ip.String())
+				} else if qt == dnsmessage.TypeAAAA && ip.Is6() {
+					answers = append(answers, ip.String())
+				}
+			}
+			return map[string]any{
+				"answers":   answers,
+				"resolvers": []any{},
+			}, nil
+		}
+
+		var p dnsmessage.Parser
+		if _, err := p.Start(res); err != nil {
+			return nil, fmt.Errorf("queryDNS: parsing response: %w", err)
+		}
+		if err := p.SkipAllQuestions(); err != nil {
+			return nil, fmt.Errorf("queryDNS: skipping questions: %w", err)
+		}
+		var answers []any
+		for {
+			h, err := p.AnswerHeader()
+			if err == dnsmessage.ErrSectionDone {
+				break
+			}
+			if err != nil {
+				return nil, fmt.Errorf("queryDNS: reading answer: %w", err)
+			}
+			switch h.Type {
+			case dnsmessage.TypeA:
+				r, err := p.AResource()
+				if err != nil {
+					return nil, fmt.Errorf("queryDNS: reading A record: %w", err)
+				}
+				answers = append(answers, netip.AddrFrom4(r.A).String())
+			case dnsmessage.TypeAAAA:
+				r, err := p.AAAAResource()
+				if err != nil {
+					return nil, fmt.Errorf("queryDNS: reading AAAA record: %w", err)
+				}
+				answers = append(answers, netip.AddrFrom16(r.AAAA).String())
+			case dnsmessage.TypeCNAME:
+				r, err := p.CNAMEResource()
+				if err != nil {
+					return nil, fmt.Errorf("queryDNS: reading CNAME record: %w", err)
+				}
+				answers = append(answers, r.CNAME.String())
+			case dnsmessage.TypeTXT:
+				r, err := p.TXTResource()
+				if err != nil {
+					return nil, fmt.Errorf("queryDNS: reading TXT record: %w", err)
+				}
+				for _, s := range r.TXT {
+					answers = append(answers, s)
+				}
+			default:
+				if err := p.SkipAnswer(); err != nil {
+					return nil, fmt.Errorf("queryDNS: skipping unknown answer: %w", err)
+				}
+			}
+		}
+		resolverAddrs := make([]any, len(resolvers))
+		for idx, r := range resolvers {
+			resolverAddrs[idx] = r.Addr
+		}
+		return map[string]any{
+			"answers":   answers,
+			"resolvers": resolverAddrs,
+		}, nil
+	})
+}
+
+func (i *jsIPN) ping(ip string, pingType string, size int) js.Value {
+	return makePromise(func() (any, error) {
+		addr, err := netip.ParseAddr(ip)
+		if err != nil {
+			return nil, fmt.Errorf("ping: invalid IP %q: %w", ip, err)
+		}
+		switch tailcfg.PingType(pingType) {
+		case tailcfg.PingDisco, tailcfg.PingTSMP, tailcfg.PingICMP, tailcfg.PingPeerAPI:
+			// valid
+		default:
+			return nil, fmt.Errorf("ping: unknown type %q, must be one of: disco, TSMP, ICMP, peerapi", pingType)
+		}
+		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+		defer cancel()
+		pr, err := i.lb.Ping(ctx, addr, tailcfg.PingType(pingType), size)
+		if err != nil {
+			return nil, err
+		}
+		result := map[string]any{
+			"ip":             pr.IP,
+			"nodeIP":         pr.NodeIP,
+			"nodeName":       pr.NodeName,
+			"latencySeconds": pr.LatencySeconds,
+			"endpoint":       pr.Endpoint,
+			"derpRegionID":   pr.DERPRegionID,
+			"derpRegionCode": pr.DERPRegionCode,
+			"peerAPIURL":     pr.PeerAPIURL,
+			"isLocalIP":      pr.IsLocalIP,
+		}
+		if pr.Err != "" {
+			result["err"] = pr.Err
+		}
+		return result, nil
+	})
+}
+
+func (i *jsIPN) suggestExitNode() js.Value {
+	return makePromise(func() (any, error) {
+		resp, err := i.lb.SuggestExitNode()
+		if err != nil {
+			return nil, err
+		}
+		result := map[string]any{
+			"id":   string(resp.ID),
+			"name": resp.Name,
+		}
+		if l := resp.Location; l.Valid() {
+			result["location"] = map[string]any{
+				"country":     l.Country(),
+				"countryCode": l.CountryCode(),
+				"city":        l.City(),
+				"cityCode":    l.CityCode(),
+				"latitude":    l.Latitude(),
+				"longitude":   l.Longitude(),
+			}
+		}
+		return result, nil
+	})
+}
+
+func (i *jsIPN) localAPI(method, path, body string) js.Value {
+	return makePromise(func() (any, error) {
+		h := localapi.NewHandler(localapi.HandlerConfig{
+			Actor: &ipnauth.TestActor{
+				Name:       "wasm",
+				LocalAdmin: true,
+			},
+			Backend:  i.lb,
+			Logf:     log.Printf,
+			LogID:    i.logID,
+			EventBus: i.lb.Sys().Bus.Get(),
+		})
+		h.PermitRead = true
+		h.PermitWrite = true
+		h.PermitCert = true
+
+		var bodyReader io.Reader
+		if body != "" {
+			bodyReader = strings.NewReader(body)
+		}
+		req, err := http.NewRequest(method, "http://local-tailscaled.sock"+path, bodyReader)
+		if err != nil {
+			return nil, fmt.Errorf("localAPI: %w", err)
+		}
+		// Empty Host passes the validHost check in the LocalAPI handler.
+		req.Host = ""
+		if body != "" {
+			req.Header.Set("Content-Type", "application/json")
+		}
+		w := httptest.NewRecorder()
+		h.ServeHTTP(w, req)
+		resp := w.Result()
+		respBody, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return nil, fmt.Errorf("localAPI: reading response: %w", err)
+		}
+		return map[string]any{
+			"status": resp.StatusCode,
+			"body":   string(respBody),
+		}, nil
+	})
+}
+
 // wrapConn exposes a net.Conn to JavaScript with binary (Uint8Array) I/O.
 func wrapConn(conn net.Conn) map[string]any {
 	return map[string]any{
@@ -995,6 +1569,7 @@ type jsNetMapNode struct {
 	Addresses   []string `json:"addresses"`
 	MachineKey  string   `json:"machineKey"`
 	NodeKey     string   `json:"nodeKey"`
+	PeerAPIURL  string   `json:"peerAPIURL,omitempty"`
 }
 
 type jsNetMapSelfNode struct {

ipn/ipnlocal/cert.go

@@ -1,7 +1,7 @@
 // Copyright (c) Tailscale Inc & contributors
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build !js && !ts_omit_acme
+//go:build !ts_omit_acme
 
 package ipnlocal
 
@@ -302,6 +302,9 @@ var errCertExpired = errors.New("cert expired")
 var testX509Roots *x509.CertPool // set non-nil by tests
 
 func (b *LocalBackend) getCertStore() (certStore, error) {
+	if runtime.GOOS == "js" {
+		return certStateStore{StateStore: b.store}, nil
+	}
 	switch b.store.(type) {
 	case *store.FileStore:
 	case *mem.Store:
@@ -333,6 +336,16 @@ func (b *LocalBackend) ConfigureCertsForTest(getCert func(hostname string) (*TLS
 	b.mu.Unlock()
 }
 
+// SetACMEHTTPClient sets a custom HTTP client for ACME certificate operations.
+// On js/wasm, this can be used to route requests through the Tailscale network
+// stack to bypass browser CORS if Let's Encrypt endpoints fail preflight.
+// A nil value (the default) uses the standard http.DefaultClient.
+func (b *LocalBackend) SetACMEHTTPClient(c *http.Client) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	b.acmeHTTPClient = c
+}
+
 // certFileStore implements certStore by storing the cert & key files in the named directory.
 type certFileStore struct {
 	dir string
@@ -550,6 +563,9 @@ var getCertPEM = func(ctx context.Context, b *LocalBackend, cs certStore, logf l
 	if err != nil {
 		return nil, err
 	}
+	b.mu.Lock()
+	ac.HTTPClient = b.acmeHTTPClient
+	b.mu.Unlock()
 
 	if !isDefaultDirectoryURL(ac.DirectoryURL) {
 		logf("acme: using Directory URL %q", ac.DirectoryURL)

ipn/ipnlocal/cert_disabled.go

@@ -1,7 +1,7 @@
 // Copyright (c) Tailscale Inc & contributors
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build js || ts_omit_acme
+//go:build ts_omit_acme
 
 package ipnlocal
 

ipn/ipnlocal/local.go

@@ -412,6 +412,10 @@ type LocalBackend struct {
 	// See [LocalBackend.ConfigureCertsForTest].
 	getCertForTest func(hostname string) (*TLSCertKeyPair, error)
 
+	// acmeHTTPClient, if non-nil, is used for all ACME HTTP requests instead
+	// of http.DefaultClient. Set via SetACMEHTTPClient before first cert use.
+	acmeHTTPClient *http.Client
+
 	// existsPendingAuthReconfig tracks if a goroutine is waiting to
 	// acquire [LocalBackend]'s mutex inside of [LocalBackend.AuthReconfig].
 	// It is used to prevent goroutines from piling up to do the same

ipn/ipnlocal/serve.go

@@ -393,6 +393,11 @@ func (b *LocalBackend) setServeConfigLocked(config *ipn.ServeConfig, etag string
 		}
 	}
 
+	// Notify the control plane immediately so that changes to IngressEnabled /
+	// WireIngress (required for Funnel DNS provisioning) are not delayed until
+	// the next periodic heartbeat.
+	b.authReconfigLocked()
+
 	return nil
 }