WIP snapshot

Next up: view support for maps, etc.

cmd/viewer/viewer.go

@@ -0,0 +1,216 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Viewer is a tool to automate the creation of a view type.
+//
+// The generated View method provides a readonly view of the struct.
+//
+// This tool makes lots of implicit assumptions about the types you feed it.
+// In particular, it can only write relatively "shallow" View methods.
+// That is, if a type contains another named struct type, viewer assumes that
+// named type will also have a View method.
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/types"
+	"log"
+	"os"
+	"strings"
+
+	"golang.org/x/tools/go/packages"
+	"tailscale.com/util/codegen"
+)
+
+var (
+	flagTypes     = flag.String("type", "", "comma-separated list of types; required")
+	flagOutput    = flag.String("output", "", "output file; required")
+	flagBuildTags = flag.String("tags", "", "compiler build tags to apply")
+)
+
+func main() {
+	log.SetFlags(0)
+	log.SetPrefix("viewer: ")
+	flag.Parse()
+	if len(*flagTypes) == 0 {
+		flag.Usage()
+		os.Exit(2)
+	}
+	typeNames := strings.Split(*flagTypes, ",")
+
+	cfg := &packages.Config{
+		Mode:  packages.NeedTypes | packages.NeedTypesInfo | packages.NeedSyntax | packages.NeedName,
+		Tests: false,
+	}
+	if *flagBuildTags != "" {
+		cfg.BuildFlags = []string{"-tags=" + *flagBuildTags}
+	}
+	pkgs, err := packages.Load(cfg, ".")
+	if err != nil {
+		log.Fatal(err)
+	}
+	if len(pkgs) != 1 {
+		log.Fatalf("wrong number of packages: %d", len(pkgs))
+	}
+	pkg := pkgs[0]
+	buf := new(bytes.Buffer)
+	imports := make(map[string]struct{})
+	namedTypes := codegen.NamedTypes(pkg)
+	for _, typeName := range typeNames {
+		typ, ok := namedTypes[typeName]
+		if !ok {
+			log.Fatalf("could not find type %s", typeName)
+		}
+		gen(buf, imports, typ, pkg.Types)
+	}
+
+	contents := new(bytes.Buffer)
+	fmt.Fprintf(contents, header, *flagTypes, pkg.Name)
+	fmt.Fprintf(contents, "import (\n")
+	for s := range imports {
+		fmt.Fprintf(contents, "\t%q\n", s)
+	}
+	fmt.Fprintf(contents, ")\n\n")
+	contents.Write(buf.Bytes())
+
+	output := *flagOutput
+	if output == "" {
+		flag.Usage()
+		os.Exit(2)
+	}
+	if err := codegen.WriteFormatted(contents.Bytes(), output); err != nil {
+		log.Fatal(err)
+	}
+}
+
+const header = `// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by the following command; DO NOT EDIT.
+//   tailscale.com/cmd/viewer -type %s
+
+package %s
+
+`
+
+func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisPkg *types.Package) {
+	pkgQual := func(pkg *types.Package) string {
+		if thisPkg == pkg {
+			return ""
+		}
+		imports[pkg.Path()] = struct{}{}
+		return pkg.Name()
+	}
+	importedName := func(t types.Type) string {
+		return types.TypeString(t, pkgQual)
+	}
+
+	t, ok := typ.Underlying().(*types.Struct)
+	if !ok {
+		return
+	}
+
+	name := typ.Obj().Name()
+	viewName := name + "View"
+	fmt.Fprintf(buf, "// View makes a readonly view of %s.\n", name)
+	fmt.Fprintf(buf, "func (src *%s) View() %s {\n", name, viewName)
+	fmt.Fprintf(buf, "	return %s{src}\n", viewName)
+	fmt.Fprintf(buf, "}\n")
+
+	fmt.Fprintf(buf, "// %s is a readonly view of %s.\n", viewName, name)
+	fmt.Fprintf(buf, "type %s struct{ ж *%s }\n", viewName, name)
+	fmt.Fprintf(buf, "func (v %s) Valid() bool { return v.ж != nil }\n", viewName)
+
+	for i := 0; i < t.NumFields(); i++ {
+		fname := t.Field(i).Name()
+		ft := t.Field(i).Type()
+		if !codegen.ContainsPointers(ft) {
+			fmt.Fprintf(buf, "func (v %s) %s() %s { return v.ж.%s }\n", viewName, fname, importedName(ft), fname)
+			continue
+		}
+		if named, _ := ft.(*types.Named); named != nil && !hasBasicUnderlying(ft) {
+			genViewCall(buf, viewName, fname, importedName(ft))
+			continue
+		}
+		switch ft := ft.Underlying().(type) {
+		case *types.Slice:
+			if !codegen.ContainsPointers(ft.Elem()) {
+				// OK to return the slice as-is, since they can't modify the contents.
+				fmt.Fprintf(buf, "func (v %s) %s() %s { return v.ж.%s }\n", viewName, fname, importedName(ft), fname)
+				continue
+			}
+
+			n := importedName(ft.Elem())
+			if ptrTyp, isPtr := ft.Elem().(*types.Pointer); isPtr {
+				n = importedName(ptrTyp.Elem())
+			}
+
+			// Generate slice view.
+			styp := fmt.Sprintf("_%s_%s", viewName, fname)
+			fmt.Fprintf(buf, "type %s []%s\n", styp, importedName(ft.Elem()))
+			fmt.Fprintf(buf, "func (s %s) Len() int { return len(s) }\n", styp)
+			fmt.Fprintf(buf, "func (s %s) At(i int) %sView { return s[i].View() }\n", styp, n)
+
+			fmt.Fprintf(buf, "func (v %s) %s() interface { Len() int; At(int) %sView } {\n", viewName, fname, n)
+			fmt.Fprintf(buf, "	return %s(v.ж.%s)\n", styp, fname)
+			fmt.Fprintf(buf, "}\n")
+		case *types.Pointer:
+			if named, _ := ft.Elem().(*types.Named); named != nil && codegen.ContainsPointers(ft.Elem()) {
+				genViewCall(buf, viewName, fname, importedName(named))
+				continue
+			}
+			if codegen.ContainsPointers(ft.Elem()) {
+				log.Fatalf("unhandled: pointers in pointers (%v)", ft)
+			}
+			n := importedName(ft.Elem())
+			fmt.Fprintf(buf, "func (v %s) %s() *%s {\n", viewName, fname, n)
+			fmt.Fprintf(buf, "	ptr := v.ж.%s\n", fname)
+			fmt.Fprintf(buf, "	if ptr == nil {\n")
+			fmt.Fprintf(buf, "		return nil\n")
+			fmt.Fprintf(buf, "	}\n")
+			fmt.Fprintf(buf, "	cp := *ptr\n")
+			fmt.Fprintf(buf, "	return &cp\n")
+			fmt.Fprintf(buf, "}\n")
+		case *types.Map:
+			// TODO: Generate map view, like the slice view.
+			// We need:
+			//   * Len() int
+			//   * Load(k) v
+			//   * LoadOK(k) (v, bool)
+			//   * Range(func(k, v) bool)
+			//
+			// Note that we need to handle a variety of elem types:
+			// basic types (float64), types with a View method,
+			// slices of the foregoing.
+			//
+			// This may require recursion to handle completely,
+			// or we can follow cloner's lead and just manually
+			// inline one level deep the code generation
+			// that we happen to need right now.
+			// (If we figure out recursion in this context,
+			// we might want to backport to cloner, too.)
+			log.Printf("TODO: Handle %s (%s)", name, ft)
+		default:
+			fmt.Fprintf(buf, `panic("TODO: %s (%T)")`, fname, ft)
+		}
+	}
+
+	buf.Write(codegen.AssertStructUnchanged(t, thisPkg, name, "View", imports))
+}
+
+func genViewCall(buf *bytes.Buffer, viewName, fieldName, importedName string) {
+	fmt.Fprintf(buf, "func (v %s) %s() %sView { return v.ж.%s.View() }\n", viewName, fieldName, importedName, fieldName)
+}
+
+func hasBasicUnderlying(typ types.Type) bool {
+	switch typ.Underlying().(type) {
+	case *types.Slice, *types.Map:
+		return true
+	default:
+		return false
+	}
+}

control/controlclient/auto.go

@@ -285,7 +285,7 @@ func (c *Auto) authRoutine() {
 			// don't send status updates for context errors,
 			// since context cancelation is always on purpose.
 			if ctx.Err() == nil {
-				c.sendStatus("authRoutine-report", err, "", nil)
+				c.sendStatus("authRoutine-report", err, "", netmap.NetworkMapView{})
 			}
 		}
 
@@ -313,7 +313,7 @@ func (c *Auto) authRoutine() {
 			c.synced = false
 			c.mu.Unlock()
 
-			c.sendStatus("authRoutine-wantout", nil, "", nil)
+			c.sendStatus("authRoutine-wantout", nil, "", netmap.NetworkMapView{})
 			bo.BackOff(ctx, nil)
 		} else { // ie. goal.wantLoggedIn
 			c.mu.Lock()
@@ -355,7 +355,7 @@ func (c *Auto) authRoutine() {
 				c.synced = false
 				c.mu.Unlock()
 
-				c.sendStatus("authRoutine-url", err, url, nil)
+				c.sendStatus("authRoutine-url", err, url, netmap.NetworkMapView{})
 				bo.BackOff(ctx, err)
 				continue
 			}
@@ -367,7 +367,7 @@ func (c *Auto) authRoutine() {
 			c.state = StateAuthenticated
 			c.mu.Unlock()
 
-			c.sendStatus("authRoutine-success", nil, "", nil)
+			c.sendStatus("authRoutine-success", nil, "", netmap.NetworkMapView{})
 			c.cancelMapSafely()
 			bo.BackOff(ctx, nil)
 		}
@@ -435,7 +435,7 @@ func (c *Auto) mapRoutine() {
 			// don't send status updates for context errors,
 			// since context cancelation is always on purpose.
 			if ctx.Err() == nil {
-				c.sendStatus("mapRoutine1", err, "", nil)
+				c.sendStatus("mapRoutine1", err, "", netmap.NetworkMapView{})
 			}
 		}
 
@@ -461,7 +461,7 @@ func (c *Auto) mapRoutine() {
 			c.mu.Unlock()
 			health.SetInPollNetMap(false)
 
-			err := c.direct.PollNetMap(ctx, -1, func(nm *netmap.NetworkMap) {
+			err := c.direct.PollNetMap(ctx, -1, func(nm netmap.NetworkMapView) {
 				health.SetInPollNetMap(true)
 				c.mu.Lock()
 
@@ -482,7 +482,7 @@ func (c *Auto) mapRoutine() {
 				if c.loggedIn {
 					c.state = StateSynchronized
 				}
-				exp := nm.Expiry
+				exp := nm.Expiry()
 				c.expiry = &exp
 				stillAuthed := c.loggedIn
 				state := c.state
@@ -563,7 +563,7 @@ func (c *Auto) SetNetInfo(ni *tailcfg.NetInfo) {
 	c.sendNewMapRequest()
 }
 
-func (c *Auto) sendStatus(who string, err error, url string, nm *netmap.NetworkMap) {
+func (c *Auto) sendStatus(who string, err error, url string, nm netmap.NetworkMapView) {
 	c.mu.Lock()
 	state := c.state
 	loggedIn := c.loggedIn
@@ -583,13 +583,13 @@ func (c *Auto) sendStatus(who string, err error, url string, nm *netmap.NetworkM
 	if state == StateNotAuthenticated {
 		logoutFin = new(empty.Message)
 	}
-	if nm != nil && loggedIn && synced {
+	if nm.Valid() && loggedIn && synced {
 		pp := c.direct.GetPersist()
 		p = &pp
 	} else {
 		// don't send netmap status, as it's misleading when we're
 		// not logged in.
-		nm = nil
+		nm = netmap.NetworkMapView{}
 	}
 	new := Status{
 		LoginFinished:  loginFin,

control/controlclient/direct.go

@@ -535,7 +535,7 @@ func inTest() bool { return flag.Lookup("test.v") != nil }
 //
 // maxPolls is how many network maps to download; common values are 1
 // or -1 (to keep a long-poll query open to the server).
-func (c *Direct) PollNetMap(ctx context.Context, maxPolls int, cb func(*netmap.NetworkMap)) error {
+func (c *Direct) PollNetMap(ctx context.Context, maxPolls int, cb func(netmap.NetworkMapView)) error {
 	return c.sendMapRequest(ctx, maxPolls, cb)
 }
 
@@ -552,7 +552,7 @@ func (c *Direct) SendLiteMapUpdate(ctx context.Context) error {
 const pollTimeout = 120 * time.Second
 
 // cb nil means to omit peers.
-func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netmap.NetworkMap)) error {
+func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(netmap.NetworkMapView)) error {
 	c.mu.Lock()
 	persist := c.persist
 	serverURL := c.serverURL
@@ -822,7 +822,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 		c.expiry = &nm.Expiry
 		c.mu.Unlock()
 
-		cb(nm)
+		cb(nm.View())
 	}
 	if ctx.Err() != nil {
 		return ctx.Err()

control/controlclient/map.go

@@ -139,7 +139,7 @@ func (ms *mapSession) netmapForResponse(resp *tailcfg.MapResponse) *netmap.Netwo
 	}
 
 	ms.addUserProfile(nm.User)
-	magicDNSSuffix := nm.MagicDNSSuffix()
+	magicDNSSuffix := nm.View().MagicDNSSuffix()
 	if nm.SelfNode != nil {
 		nm.SelfNode.InitDisplayNames(magicDNSSuffix)
 	}

control/controlclient/status.go

@@ -69,7 +69,7 @@ type Status struct {
 	LogoutFinished *empty.Message // nonempty when logout finishes
 	Err            string
 	URL            string                // interactive URL to visit to finish logging in
-	NetMap         *netmap.NetworkMap // server-pushed configuration
+	NetMap         netmap.NetworkMapView // server-pushed configuration
 
 	// The internal state should not be exposed outside this
 	// package, but we have some automated tests elsewhere that need to

ipn/ipnlocal/local.go

@@ -115,8 +115,7 @@ type LocalBackend struct {
 	capFileSharing bool // whether netMap contains the file sharing capability
 	// hostinfo is mutated in-place while mu is held.
 	hostinfo         *tailcfg.Hostinfo
-	// netMap is not mutated in-place once set.
+	netMap           netmap.NetworkMapView
-	netMap           *netmap.NetworkMap
 	nodeByAddr       map[netaddr.IP]*tailcfg.Node
 	activeLogin      string // last logged LoginName from netMap
 	engineStatus     ipn.EngineStatus
@@ -224,7 +223,7 @@ func (b *LocalBackend) maybePauseControlClientLocked() {
 		return
 	}
 	networkUp := b.prevIfState.AnyInterfaceUp()
-	b.cc.SetPaused((b.state == ipn.Stopped && b.netMap != nil) || !networkUp)
+	b.cc.SetPaused((b.state == ipn.Stopped && b.netMap.Valid()) || !networkUp)
 }
 
 // linkChange is our link monitor callback, called whenever the network changes.
@@ -253,8 +252,8 @@ func (b *LocalBackend) linkChange(major bool, ifst *interfaces.State) {
 	// need updating to tweak default routes.
 	b.updateFilter(b.netMap, b.prefs)
 
-	if peerAPIListenAsync && b.netMap != nil && b.state == ipn.Running {
+	if peerAPIListenAsync && b.netMap.Valid() && b.state == ipn.Running {
-		want := len(b.netMap.Addresses)
+		want := len(b.netMap.Addresses())
 		if len(b.peerAPIListeners) < want {
 			b.logf("linkChange: peerAPIListeners too low; trying again")
 			go b.initPeerAPIListener()
@@ -343,14 +342,14 @@ func (b *LocalBackend) updateStatus(sb *ipnstate.StatusBuilder, extraLocked func
 				s.Health = append(s.Health, err.Error())
 			}
 		}
-		if b.netMap != nil {
+		if b.netMap.Valid() {
 			s.MagicDNSSuffix = b.netMap.MagicDNSSuffix()
-			s.CertDomains = append([]string(nil), b.netMap.DNS.CertDomains...)
+			s.CertDomains = append([]string(nil), b.netMap.DNS().CertDomains()...)
 		}
 	})
 	sb.MutateSelfStatus(func(ss *ipnstate.PeerStatus) {
-		if b.netMap != nil && b.netMap.SelfNode != nil {
+		if b.netMap.Valid() && b.netMap.SelfNode != nil {
-			ss.ID = b.netMap.SelfNode.StableID
+			ss.ID = b.netMap.SelfNode().StableID()
 		}
 		for _, pln := range b.peerAPIListeners {
 			ss.PeerAPIURL = append(ss.PeerAPIURL, pln.urlStr)
@@ -365,20 +364,21 @@ func (b *LocalBackend) updateStatus(sb *ipnstate.StatusBuilder, extraLocked func
 }
 
 func (b *LocalBackend) populatePeerStatusLocked(sb *ipnstate.StatusBuilder) {
-	if b.netMap == nil {
+	if !b.netMap.Valid() {
 		return
 	}
-	for id, up := range b.netMap.UserProfiles {
+	for _, id := range b.netMap.UserIDs() {
+		up := b.netMap.UserProfile(id)
 		sb.AddUser(id, up)
 	}
-	for _, p := range b.netMap.Peers {
+	for _, p := range b.netMap.Peers() {
 		var lastSeen time.Time
-		if p.LastSeen != nil {
+		if p.LastSeen() != nil {
-			lastSeen = *p.LastSeen
+			lastSeen = *p.LastSeen()
 		}
 		var tailAddr4 string
-		var tailscaleIPs = make([]netaddr.IP, 0, len(p.Addresses))
+		var tailscaleIPs = make([]netaddr.IP, 0, len(p.Addresses()))
-		for _, addr := range p.Addresses {
+		for _, addr := range p.Addresses() {
 			if addr.IsSingleIP() && tsaddr.IsTailscaleIP(addr.IP()) {
 				if addr.IP().Is4() && tailAddr4 == "" {
 					// The peer struct previously only allowed a single
@@ -389,20 +389,20 @@ func (b *LocalBackend) populatePeerStatusLocked(sb *ipnstate.StatusBuilder) {
 				tailscaleIPs = append(tailscaleIPs, addr.IP())
 			}
 		}
-		sb.AddPeer(key.Public(p.Key), &ipnstate.PeerStatus{
+		sb.AddPeer(key.Public(p.Key()), &ipnstate.PeerStatus{
 			InNetworkMap:       true,
-			ID:                 p.StableID,
+			ID:                 p.StableID(),
-			UserID:             p.User,
+			UserID:             p.User(),
 			TailAddrDeprecated: tailAddr4,
 			TailscaleIPs:       tailscaleIPs,
-			HostName:           p.Hostinfo.Hostname,
+			HostName:           p.Hostinfo().Hostname(),
-			DNSName:            p.Name,
+			DNSName:            p.Name(),
-			OS:                 p.Hostinfo.OS,
+			OS:                 p.Hostinfo().OS(),
-			KeepAlive:          p.KeepAlive,
+			KeepAlive:          p.KeepAlive(),
-			Created:            p.Created,
+			Created:            p.Created(),
 			LastSeen:           lastSeen,
-			ShareeNode:         p.Hostinfo.ShareeNode,
+			ShareeNode:         p.Hostinfo().ShareeNode(),
-			ExitNode:           p.StableID != "" && p.StableID == b.prefs.ExitNodeID,
+			ExitNode:           p.StableID() != "" && p.StableID() == b.prefs.ExitNodeID,
 		})
 	}
 }
@@ -478,7 +478,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 		// Since we're logged out now, our netmap cache is invalid.
 		// Since st.NetMap==nil means "netmap is unchanged", there is
 		// no other way to represent this change.
-		b.setNetMapLocked(nil)
+		b.setNetMapLocked(netmap.NetworkMapView{})
 	}
 
 	prefs := b.prefs
@@ -501,7 +501,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 			b.prefs.Persist = st.Persist.Clone()
 		}
 	}
-	if st.NetMap != nil {
+	if st.NetMap.Valid() {
 		if b.findExitNodeIDLocked(st.NetMap) {
 			prefsChanged = true
 		}
@@ -537,8 +537,8 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 		}
 		b.send(ipn.Notify{Prefs: prefs})
 	}
-	if st.NetMap != nil {
+	if st.NetMap.Valid() {
-		if netMap != nil {
+		if netMap.Valid() {
 			diff := st.NetMap.ConciseDiffFrom(netMap)
 			if strings.TrimSpace(diff) == "" {
 				b.logf("[v1] netmap diff: (none)")
@@ -567,7 +567,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 
 // findExitNodeIDLocked updates b.prefs to reference an exit node by ID,
 // rather than by IP. It returns whether prefs was mutated.
-func (b *LocalBackend) findExitNodeIDLocked(nm *netmap.NetworkMap) (prefsChanged bool) {
+func (b *LocalBackend) findExitNodeIDLocked(nm netmap.NetworkMapView) (prefsChanged bool) {
 	// If we have a desired IP on file, try to find the corresponding
 	// node.
 	if b.prefs.ExitNodeIP.IsZero() {
@@ -580,14 +580,16 @@ func (b *LocalBackend) findExitNodeIDLocked(nm *netmap.NetworkMap) (prefsChanged
 		prefsChanged = true
 	}
 
-	for _, peer := range nm.Peers {
+	peers := nm.Peers()
-		for _, addr := range peer.Addresses {
+	for i := 0; i < peers.Len(); i++ {
+		peer := peers.At(i)
+		for _, addr := range peer.Addresses() {
 			if !addr.IsSingleIP() || addr.IP() != b.prefs.ExitNodeIP {
 				continue
 			}
 			// Found the node being referenced, upgrade prefs to
 			// reference it directly for next time.
-			b.prefs.ExitNodeID = peer.StableID
+			b.prefs.ExitNodeID = peer.StableID()
 			b.prefs.ExitNodeIP = netaddr.IP{}
 			return true
 		}
@@ -922,14 +924,14 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 
 // updateFilter updates the packet filter in wgengine based on the
 // given netMap and user preferences.
-func (b *LocalBackend) updateFilter(netMap *netmap.NetworkMap, prefs *ipn.Prefs) {
+func (b *LocalBackend) updateFilter(netMap netmap.NetworkMapView, prefs *ipn.Prefs) {
 	// NOTE(danderson): keep change detection as the first thing in
 	// this function. Don't try to optimize by returning early, more
 	// likely than not you'll just end up breaking the change
 	// detection and end up with the wrong filter installed. This is
 	// quite hard to debug, so save yourself the trouble.
 	var (
-		haveNetmap   = netMap != nil
+		haveNetmap   = netMap.Valid()
 		addrs        []netaddr.IPPrefix
 		packetFilter []filter.Match
 		localNetsB   netaddr.IPSetBuilder
@@ -941,7 +943,7 @@ func (b *LocalBackend) updateFilter(netMap *netmap.NetworkMap, prefs *ipn.Prefs)
 	logNetsB.AddPrefix(tsaddr.TailscaleULARange())
 	logNetsB.RemovePrefix(tsaddr.ChromeOSVMRange())
 	if haveNetmap {
-		addrs = netMap.Addresses
+		addrs = netMap.Addresses()
 		for _, p := range addrs {
 			localNetsB.AddPrefix(p)
 		}
@@ -2533,10 +2535,10 @@ func hasCapability(nm *netmap.NetworkMap, cap string) bool {
 	return false
 }
 
-func (b *LocalBackend) setNetMapLocked(nm *netmap.NetworkMap) {
+func (b *LocalBackend) setNetMapLocked(nm netmap.NetworkMapView) {
 	var login string
-	if nm != nil {
+	if nm.Valid() {
-		login = nm.UserProfiles[nm.User].LoginName
+		login = nm.UserProfile(nm.User()).LoginName
 		if login == "" {
 			login = "<missing-profile>"
 		}

tailcfg/tailcfg.go

@@ -5,6 +5,7 @@
 package tailcfg
 
 //go:generate go run tailscale.com/cmd/cloner --type=User,Node,Hostinfo,NetInfo,Login,DNSConfig,RegisterResponse,DERPRegion,DERPMap,DERPNode --clonefunc=true --output=tailcfg_clone.go
+//go:generate go run tailscale.com/cmd/viewer --type=Node,Hostinfo,DNSConfig,NetInfo,DERPMap --output=tailcfg_view.go
 
 import (
 	"encoding/hex"

tailcfg/tailcfg_view.go

@@ -0,0 +1,239 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by the following command; DO NOT EDIT.
+//   tailscale.com/cmd/viewer -type Node,Hostinfo,DNSConfig,NetInfo,DERPMap
+
+package tailcfg
+
+import (
+	"inet.af/netaddr"
+	"tailscale.com/types/dnstype"
+	"tailscale.com/types/key"
+	"tailscale.com/types/opt"
+	"time"
+)
+
+// View makes a readonly view of Node.
+func (src *Node) View() NodeView {
+	return NodeView{src}
+}
+
+// NodeView is a readonly view of Node.
+type NodeView struct{ ж *Node }
+
+func (v NodeView) Valid() bool                       { return v.ж != nil }
+func (v NodeView) ID() NodeID                        { return v.ж.ID }
+func (v NodeView) StableID() StableNodeID            { return v.ж.StableID }
+func (v NodeView) Name() string                      { return v.ж.Name }
+func (v NodeView) User() UserID                      { return v.ж.User }
+func (v NodeView) Sharer() UserID                    { return v.ж.Sharer }
+func (v NodeView) Key() NodeKey                      { return v.ж.Key }
+func (v NodeView) KeyExpiry() time.Time              { return v.ж.KeyExpiry }
+func (v NodeView) Machine() key.MachinePublic        { return v.ж.Machine }
+func (v NodeView) DiscoKey() DiscoKey                { return v.ж.DiscoKey }
+func (v NodeView) Addresses() []netaddr.IPPrefix     { return v.ж.Addresses }
+func (v NodeView) AllowedIPs() []netaddr.IPPrefix    { return v.ж.AllowedIPs }
+func (v NodeView) Endpoints() []string               { return v.ж.Endpoints }
+func (v NodeView) DERP() string                      { return v.ж.DERP }
+func (v NodeView) Hostinfo() HostinfoView            { return v.ж.Hostinfo.View() }
+func (v NodeView) Created() time.Time                { return v.ж.Created }
+func (v NodeView) PrimaryRoutes() []netaddr.IPPrefix { return v.ж.PrimaryRoutes }
+func (v NodeView) LastSeen() *time.Time {
+	ptr := v.ж.LastSeen
+	if ptr == nil {
+		return nil
+	}
+	cp := *ptr
+	return &cp
+}
+func (v NodeView) Online() *bool {
+	ptr := v.ж.Online
+	if ptr == nil {
+		return nil
+	}
+	cp := *ptr
+	return &cp
+}
+func (v NodeView) KeepAlive() bool                 { return v.ж.KeepAlive }
+func (v NodeView) MachineAuthorized() bool         { return v.ж.MachineAuthorized }
+func (v NodeView) Capabilities() []string          { return v.ж.Capabilities }
+func (v NodeView) ComputedName() string            { return v.ж.ComputedName }
+func (v NodeView) computedHostIfDifferent() string { return v.ж.computedHostIfDifferent }
+func (v NodeView) ComputedNameWithHost() string    { return v.ж.ComputedNameWithHost }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _NodeViewNeedsRegeneration = Node(struct {
+	ID                      NodeID
+	StableID                StableNodeID
+	Name                    string
+	User                    UserID
+	Sharer                  UserID
+	Key                     NodeKey
+	KeyExpiry               time.Time
+	Machine                 key.MachinePublic
+	DiscoKey                DiscoKey
+	Addresses               []netaddr.IPPrefix
+	AllowedIPs              []netaddr.IPPrefix
+	Endpoints               []string
+	DERP                    string
+	Hostinfo                Hostinfo
+	Created                 time.Time
+	PrimaryRoutes           []netaddr.IPPrefix
+	LastSeen                *time.Time
+	Online                  *bool
+	KeepAlive               bool
+	MachineAuthorized       bool
+	Capabilities            []string
+	ComputedName            string
+	computedHostIfDifferent string
+	ComputedNameWithHost    string
+}{})
+
+// View makes a readonly view of Hostinfo.
+func (src *Hostinfo) View() HostinfoView {
+	return HostinfoView{src}
+}
+
+// HostinfoView is a readonly view of Hostinfo.
+type HostinfoView struct{ ж *Hostinfo }
+
+func (v HostinfoView) Valid() bool                     { return v.ж != nil }
+func (v HostinfoView) IPNVersion() string              { return v.ж.IPNVersion }
+func (v HostinfoView) FrontendLogID() string           { return v.ж.FrontendLogID }
+func (v HostinfoView) BackendLogID() string            { return v.ж.BackendLogID }
+func (v HostinfoView) OS() string                      { return v.ж.OS }
+func (v HostinfoView) OSVersion() string               { return v.ж.OSVersion }
+func (v HostinfoView) Package() string                 { return v.ж.Package }
+func (v HostinfoView) DeviceModel() string             { return v.ж.DeviceModel }
+func (v HostinfoView) Hostname() string                { return v.ж.Hostname }
+func (v HostinfoView) ShieldsUp() bool                 { return v.ж.ShieldsUp }
+func (v HostinfoView) ShareeNode() bool                { return v.ж.ShareeNode }
+func (v HostinfoView) GoArch() string                  { return v.ж.GoArch }
+func (v HostinfoView) RoutableIPs() []netaddr.IPPrefix { return v.ж.RoutableIPs }
+func (v HostinfoView) RequestTags() []string           { return v.ж.RequestTags }
+func (v HostinfoView) Services() []Service             { return v.ж.Services }
+func (v HostinfoView) NetInfo() NetInfoView            { return v.ж.NetInfo.View() }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _HostinfoViewNeedsRegeneration = Hostinfo(struct {
+	IPNVersion    string
+	FrontendLogID string
+	BackendLogID  string
+	OS            string
+	OSVersion     string
+	Package       string
+	DeviceModel   string
+	Hostname      string
+	ShieldsUp     bool
+	ShareeNode    bool
+	GoArch        string
+	RoutableIPs   []netaddr.IPPrefix
+	RequestTags   []string
+	Services      []Service
+	NetInfo       *NetInfo
+}{})
+
+// View makes a readonly view of DNSConfig.
+func (src *DNSConfig) View() DNSConfigView {
+	return DNSConfigView{src}
+}
+
+// DNSConfigView is a readonly view of DNSConfig.
+type DNSConfigView struct{ ж *DNSConfig }
+
+func (v DNSConfigView) Valid() bool { return v.ж != nil }
+
+type _DNSConfigView_Resolvers []dnstype.Resolver
+
+func (s _DNSConfigView_Resolvers) Len() int                      { return len(s) }
+func (s _DNSConfigView_Resolvers) At(i int) dnstype.ResolverView { return s[i].View() }
+func (v DNSConfigView) Resolvers() interface {
+	Len() int
+	At(int) dnstype.ResolverView
+} {
+	return _DNSConfigView_Resolvers(v.ж.Resolvers)
+}
+
+type _DNSConfigView_FallbackResolvers []dnstype.Resolver
+
+func (s _DNSConfigView_FallbackResolvers) Len() int                      { return len(s) }
+func (s _DNSConfigView_FallbackResolvers) At(i int) dnstype.ResolverView { return s[i].View() }
+func (v DNSConfigView) FallbackResolvers() interface {
+	Len() int
+	At(int) dnstype.ResolverView
+} {
+	return _DNSConfigView_FallbackResolvers(v.ж.FallbackResolvers)
+}
+func (v DNSConfigView) Domains() []string         { return v.ж.Domains }
+func (v DNSConfigView) Proxied() bool             { return v.ж.Proxied }
+func (v DNSConfigView) Nameservers() []netaddr.IP { return v.ж.Nameservers }
+func (v DNSConfigView) PerDomain() bool           { return v.ж.PerDomain }
+func (v DNSConfigView) CertDomains() []string     { return v.ж.CertDomains }
+func (v DNSConfigView) ExtraRecords() []DNSRecord { return v.ж.ExtraRecords }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _DNSConfigViewNeedsRegeneration = DNSConfig(struct {
+	Resolvers         []dnstype.Resolver
+	Routes            map[string][]dnstype.Resolver
+	FallbackResolvers []dnstype.Resolver
+	Domains           []string
+	Proxied           bool
+	Nameservers       []netaddr.IP
+	PerDomain         bool
+	CertDomains       []string
+	ExtraRecords      []DNSRecord
+}{})
+
+// View makes a readonly view of NetInfo.
+func (src *NetInfo) View() NetInfoView {
+	return NetInfoView{src}
+}
+
+// NetInfoView is a readonly view of NetInfo.
+type NetInfoView struct{ ж *NetInfo }
+
+func (v NetInfoView) Valid() bool                     { return v.ж != nil }
+func (v NetInfoView) MappingVariesByDestIP() opt.Bool { return v.ж.MappingVariesByDestIP }
+func (v NetInfoView) HairPinning() opt.Bool           { return v.ж.HairPinning }
+func (v NetInfoView) WorkingIPv6() opt.Bool           { return v.ж.WorkingIPv6 }
+func (v NetInfoView) WorkingUDP() opt.Bool            { return v.ж.WorkingUDP }
+func (v NetInfoView) HavePortMap() bool               { return v.ж.HavePortMap }
+func (v NetInfoView) UPnP() opt.Bool                  { return v.ж.UPnP }
+func (v NetInfoView) PMP() opt.Bool                   { return v.ж.PMP }
+func (v NetInfoView) PCP() opt.Bool                   { return v.ж.PCP }
+func (v NetInfoView) PreferredDERP() int              { return v.ж.PreferredDERP }
+func (v NetInfoView) LinkType() string                { return v.ж.LinkType }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _NetInfoViewNeedsRegeneration = NetInfo(struct {
+	MappingVariesByDestIP opt.Bool
+	HairPinning           opt.Bool
+	WorkingIPv6           opt.Bool
+	WorkingUDP            opt.Bool
+	HavePortMap           bool
+	UPnP                  opt.Bool
+	PMP                   opt.Bool
+	PCP                   opt.Bool
+	PreferredDERP         int
+	LinkType              string
+	DERPLatency           map[string]float64
+}{})
+
+// View makes a readonly view of DERPMap.
+func (src *DERPMap) View() DERPMapView {
+	return DERPMapView{src}
+}
+
+// DERPMapView is a readonly view of DERPMap.
+type DERPMapView struct{ ж *DERPMap }
+
+func (v DERPMapView) Valid() bool              { return v.ж != nil }
+func (v DERPMapView) OmitDefaultRegions() bool { return v.ж.OmitDefaultRegions }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _DERPMapViewNeedsRegeneration = DERPMap(struct {
+	Regions            map[int]*DERPRegion
+	OmitDefaultRegions bool
+}{})

types/dnstype/dnstype.go

@@ -6,6 +6,7 @@
 package dnstype
 
 //go:generate go run tailscale.com/cmd/cloner --type=Resolver --clonefunc=true --output=dnstype_clone.go
+//go:generate go run tailscale.com/cmd/viewer --type=Resolver --output=dnstype_view.go
 
 import "inet.af/netaddr"
 

types/dnstype/dnstype_view.go

@@ -0,0 +1,30 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by the following command; DO NOT EDIT.
+//   tailscale.com/cmd/viewer -type Resolver
+
+package dnstype
+
+import (
+	"inet.af/netaddr"
+)
+
+// View makes a readonly view of Resolver.
+func (src *Resolver) View() ResolverView {
+	return ResolverView{src}
+}
+
+// ResolverView is a readonly view of Resolver.
+type ResolverView struct{ ж *Resolver }
+
+func (v ResolverView) Valid() bool                       { return v.ж != nil }
+func (v ResolverView) Addr() string                      { return v.ж.Addr }
+func (v ResolverView) BootstrapResolution() []netaddr.IP { return v.ж.BootstrapResolution }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _ResolverViewNeedsRegeneration = Resolver(struct {
+	Addr                string
+	BootstrapResolution []netaddr.IP
+}{})

types/netmap/netmap.go

@@ -5,6 +5,8 @@
 // Package netmap contains the netmap.NetworkMap type.
 package netmap
 
+//go:generate go run tailscale.com/cmd/viewer --type=NetworkMap --output=netmap_view.go
+
 import (
 	"encoding/json"
 	"fmt"
@@ -66,8 +68,8 @@ type NetworkMap struct {
 // MagicDNS isn't necessarily in use).
 //
 // It will neither start nor end with a period.
-func (nm *NetworkMap) MagicDNSSuffix() string {
+func (nm NetworkMapView) MagicDNSSuffix() string {
-	name := strings.Trim(nm.Name, ".")
+	name := strings.Trim(nm.Name(), ".")
 	if i := strings.Index(name, "."); i != -1 {
 		name = name[i+1:]
 	}

types/netmap/netmap_view.go

@@ -0,0 +1,95 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by the following command; DO NOT EDIT.
+//   tailscale.com/cmd/viewer -type NetworkMap
+
+package netmap
+
+import (
+	"inet.af/netaddr"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/key"
+	"tailscale.com/types/wgkey"
+	"tailscale.com/wgengine/filter"
+	"time"
+)
+
+// View makes a readonly view of NetworkMap.
+func (src *NetworkMap) View() NetworkMapView {
+	return NetworkMapView{src}
+}
+
+// NetworkMapView is a readonly view of NetworkMap.
+type NetworkMapView struct{ ж *NetworkMap }
+
+func (v NetworkMapView) Valid() bool                          { return v.ж != nil }
+func (v NetworkMapView) SelfNode() tailcfg.NodeView           { return v.ж.SelfNode.View() }
+func (v NetworkMapView) NodeKey() tailcfg.NodeKey             { return v.ж.NodeKey }
+func (v NetworkMapView) PrivateKey() wgkey.Private            { return v.ж.PrivateKey }
+func (v NetworkMapView) Expiry() time.Time                    { return v.ж.Expiry }
+func (v NetworkMapView) Name() string                         { return v.ж.Name }
+func (v NetworkMapView) Addresses() []netaddr.IPPrefix        { return v.ж.Addresses }
+func (v NetworkMapView) LocalPort() uint16                    { return v.ж.LocalPort }
+func (v NetworkMapView) MachineStatus() tailcfg.MachineStatus { return v.ж.MachineStatus }
+func (v NetworkMapView) MachineKey() key.MachinePublic        { return v.ж.MachineKey }
+
+type _NetworkMapView_Peers []*tailcfg.Node
+
+func (s _NetworkMapView_Peers) Len() int                  { return len(s) }
+func (s _NetworkMapView_Peers) At(i int) tailcfg.NodeView { return s[i].View() }
+func (v NetworkMapView) Peers() interface {
+	Len() int
+	At(int) tailcfg.NodeView
+} {
+	return _NetworkMapView_Peers(v.ж.Peers)
+}
+func (v NetworkMapView) DNS() tailcfg.DNSConfigView     { return v.ж.DNS.View() }
+func (v NetworkMapView) Hostinfo() tailcfg.HostinfoView { return v.ж.Hostinfo.View() }
+
+type _NetworkMapView_PacketFilter []filter.Match
+
+func (s _NetworkMapView_PacketFilter) Len() int                  { return len(s) }
+func (s _NetworkMapView_PacketFilter) At(i int) filter.MatchView { return s[i].View() }
+func (v NetworkMapView) PacketFilter() interface {
+	Len() int
+	At(int) filter.MatchView
+} {
+	return _NetworkMapView_PacketFilter(v.ж.PacketFilter)
+}
+func (v NetworkMapView) CollectServices() bool        { return v.ж.CollectServices }
+func (v NetworkMapView) DERPMap() tailcfg.DERPMapView { return v.ж.DERPMap.View() }
+func (v NetworkMapView) Debug() *tailcfg.Debug {
+	ptr := v.ж.Debug
+	if ptr == nil {
+		return nil
+	}
+	cp := *ptr
+	return &cp
+}
+func (v NetworkMapView) User() tailcfg.UserID { return v.ж.User }
+func (v NetworkMapView) Domain() string       { return v.ж.Domain }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _NetworkMapViewNeedsRegeneration = NetworkMap(struct {
+	SelfNode        *tailcfg.Node
+	NodeKey         tailcfg.NodeKey
+	PrivateKey      wgkey.Private
+	Expiry          time.Time
+	Name            string
+	Addresses       []netaddr.IPPrefix
+	LocalPort       uint16
+	MachineStatus   tailcfg.MachineStatus
+	MachineKey      key.MachinePublic
+	Peers           []*tailcfg.Node
+	DNS             tailcfg.DNSConfig
+	Hostinfo        tailcfg.Hostinfo
+	PacketFilter    []filter.Match
+	CollectServices bool
+	DERPMap         *tailcfg.DERPMap
+	Debug           *tailcfg.Debug
+	User            tailcfg.UserID
+	Domain          string
+	UserProfiles    map[tailcfg.UserID]tailcfg.UserProfile
+}{})

wgengine/filter/match.go

@@ -14,6 +14,7 @@ import (
 )
 
 //go:generate go run tailscale.com/cmd/cloner --type=Match --output=match_clone.go
+//go:generate go run tailscale.com/cmd/viewer --type=Match --output=match_view.go
 
 // PortRange is a range of TCP and UDP ports.
 type PortRange struct {

wgengine/filter/match_view.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by the following command; DO NOT EDIT.
+//   tailscale.com/cmd/viewer -type Match
+
+package filter
+
+import (
+	"inet.af/netaddr"
+	"tailscale.com/types/ipproto"
+)
+
+// View makes a readonly view of Match.
+func (src *Match) View() MatchView {
+	return MatchView{src}
+}
+
+// MatchView is a readonly view of Match.
+type MatchView struct{ ж *Match }
+
+func (v MatchView) Valid() bool              { return v.ж != nil }
+func (v MatchView) IPProto() []ipproto.Proto { return v.ж.IPProto }
+func (v MatchView) Dsts() []NetPortRange     { return v.ж.Dsts }
+func (v MatchView) Srcs() []netaddr.IPPrefix { return v.ж.Srcs }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _MatchViewNeedsRegeneration = Match(struct {
+	IPProto []ipproto.Proto
+	Dsts    []NetPortRange
+	Srcs    []netaddr.IPPrefix
+}{})

wgengine/netstack/netstack.go

@@ -176,7 +176,7 @@ type DNSMap map[string]netaddr.IP
 
 func DNSMapFromNetworkMap(nm *netmap.NetworkMap) DNSMap {
 	ret := make(DNSMap)
-	suffix := nm.MagicDNSSuffix()
+	suffix := nm.View().MagicDNSSuffix()
 	have4 := false
 	if nm.Name != "" && len(nm.Addresses) > 0 {
 		ip := nm.Addresses[0].IP()