ipn/ipnlocal: use ServerConfig views internally

Updates tailscale/corp#7515

Change-Id: Ica2bc44b92d281d5ce16cee55b7ca51c7910145c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/ipnlocal/local.go

@@ -199,7 +199,7 @@ type LocalBackend struct {
 
 	// ServeConfig fields. (also guarded by mu)
 	lastServeConfJSON mem.RO              // last JSON that was parsed into serveConfig
-	serveConfig       ipn.ServeConfig // only replaced wholesale; don't mutate in-place
+	serveConfig       ipn.ServeConfigView // or !Valid if none
 
 	// statusLock must be held before calling statusChanged.Wait() or
 	// statusChanged.Broadcast().
@@ -3514,13 +3514,18 @@ func (b *LocalBackend) setTCPPortsInterceptedFromNetmapAndPrefsLocked() {
 				var conf ipn.ServeConfig
 				if err := json.Unmarshal(confj, &conf); err != nil {
 					b.logf("invalid ServeConfig %q in StateStore: %v", confKey, err)
+					b.serveConfig = ipn.ServeConfigView{}
+				} else {
+					b.serveConfig = conf.View()
 				}
-				b.serveConfig = conf
 			}
-			for p := range b.serveConfig.TCP {
+			if b.serveConfig.Valid() {
-				if p > 0 && p <= math.MaxUint16 {
+				b.serveConfig.TCP().Range(func(port int, _ ipn.TCPPortHandlerView) bool {
-					handlePorts = append(handlePorts, uint16(p))
+					if port > 0 && port <= math.MaxUint16 {
+						handlePorts = append(handlePorts, uint16(port))
 					}
+					return true
+				})
 			}
 		}
 	}

ipn/ipnlocal/serve.go

@@ -38,9 +38,11 @@ func (b *LocalBackend) HandleInterceptedTCPConn(c net.Conn) {
 	hs.ServeTLS(netutil.NewOneConnListener(c, nil), "", "")
 }
 
-func (b *LocalBackend) getServeHandler(r *http.Request) (_ *ipn.HTTPHandler, ok bool) {
+func (b *LocalBackend) getServeHandler(r *http.Request) (_ ipn.HTTPHandlerView, ok bool) {
+	var z ipn.HTTPHandlerView // zero value
+
 	if r.TLS == nil {
-		return nil, false
+		return z, false
 	}
 
 	sni := r.TLS.ServerName
@@ -50,17 +52,21 @@ func (b *LocalBackend) getServeHandler(r *http.Request) (_ *ipn.HTTPHandler, ok
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
-	wsc, ok := b.serveConfig.Web[key]
+	if !b.serveConfig.Valid() {
+		return z, false
+	}
+
+	wsc, ok := b.serveConfig.Web().GetOk(key)
 	if !ok {
-		return nil, false
+		return z, false
 	}
 	path := r.URL.Path
 	for {
-		if h, ok := wsc.Handlers[path]; ok {
+		if h, ok := wsc.Handlers().GetOk(path); ok {
 			return h, true
 		}
 		if path == "/" {
-			return nil, false
+			return z, false
 		}
 		path = pathpkg.Dir(path)
 	}
@@ -72,16 +78,16 @@ func (b *LocalBackend) serveWebHandler(w http.ResponseWriter, r *http.Request) {
 		http.NotFound(w, r)
 		return
 	}
-	if s := h.Text; s != "" {
+	if s := h.Text(); s != "" {
 		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 		io.WriteString(w, s)
 		return
 	}
-	if v := h.Path; v != "" {
+	if v := h.Path(); v != "" {
 		io.WriteString(w, "TODO(bradfitz): serve file")
 		return
 	}
-	if v := h.Proxy; v != "" {
+	if v := h.Proxy(); v != "" {
 		io.WriteString(w, "TODO(bradfitz): proxy")
 		return
 	}