all: use buildfeatures consts in a few more places

Saves ~25 KB.

Updates #12614

Change-Id: I7b976e57819a0d2692824d779c8cc98033df0d30
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

client/local/local.go

@@ -752,6 +752,9 @@ func (lc *Client) PushFile(ctx context.Context, target tailcfg.StableNodeID, siz
 // machine is properly configured to forward IP packets as a subnet router
 // or exit node.
 func (lc *Client) CheckIPForwarding(ctx context.Context) error {
+	if !buildfeatures.HasAdvertiseRoutes {
+		return nil
+	}
 	body, err := lc.get200(ctx, "/localapi/v0/check-ip-forwarding")
 	if err != nil {
 		return err

cmd/tailscale/cli/up.go

@@ -24,6 +24,7 @@ import (
 	shellquote "github.com/kballard/go-shellquote"
 	"github.com/peterbourgon/ff/v3/ffcli"
 	qrcode "github.com/skip2/go-qrcode"
+	"tailscale.com/feature/buildfeatures"
 	_ "tailscale.com/feature/condregister/oauthkey"
 	"tailscale.com/health/healthmsg"
 	"tailscale.com/internal/client/tailscale"
@@ -1136,7 +1137,8 @@ func exitNodeIP(p *ipn.Prefs, st *ipnstate.Status) (ip netip.Addr) {
 }
 
 func warnOnAdvertiseRoutes(ctx context.Context, prefs *ipn.Prefs) {
-	if len(prefs.AdvertiseRoutes) > 0 || prefs.AppConnector.Advertise {
+	if buildfeatures.HasAdvertiseRoutes && len(prefs.AdvertiseRoutes) > 0 ||
+		buildfeatures.HasAppConnectors && prefs.AppConnector.Advertise {
 		// TODO(jwhited): compress CheckIPForwarding and CheckUDPGROForwarding
 		//  into a single HTTP req.
 		if err := localClient.CheckIPForwarding(ctx); err != nil {

control/controlclient/direct.go

@@ -945,7 +945,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, isStreaming bool, nu Netmap
 		ConnectionHandleForTest: connectionHandleForTest,
 	}
 	var extraDebugFlags []string
-	if hi != nil && c.netMon != nil && !c.skipIPForwardingCheck &&
+	if buildfeatures.HasAdvertiseRoutes && hi != nil && c.netMon != nil && !c.skipIPForwardingCheck &&
 		ipForwardingBroken(hi.RoutableIPs, c.netMon.InterfaceState()) {
 		extraDebugFlags = append(extraDebugFlags, "warn-ip-forwarding-off")
 	}

ipn/ipnlocal/local.go

@@ -586,7 +586,12 @@ func NewLocalBackend(logf logger.Logf, logID logid.PublicID, sys *tsd.System, lo
 func (b *LocalBackend) consumeEventbusTopics(ec *eventbus.Client) func(*eventbus.Client) {
 	clientVersionSub := eventbus.Subscribe[tailcfg.ClientVersion](ec)
 	autoUpdateSub := eventbus.Subscribe[controlclient.AutoUpdate](ec)
+
+	var healthChange <-chan health.Change
+	if buildfeatures.HasHealth {
 		healthChangeSub := eventbus.Subscribe[health.Change](ec)
+		healthChange = healthChangeSub.Events()
+	}
 	changeDeltaSub := eventbus.Subscribe[netmon.ChangeDelta](ec)
 
 	var portlist <-chan PortlistServices
@@ -604,7 +609,7 @@ func (b *LocalBackend) consumeEventbusTopics(ec *eventbus.Client) func(*eventbus
 				b.onClientVersion(&clientVersion)
 			case au := <-autoUpdateSub.Events():
 				b.onTailnetDefaultAutoUpdate(au.Value)
-			case change := <-healthChangeSub.Events():
+			case change := <-healthChange:
 				b.onHealthChange(change)
 			case changeDelta := <-changeDeltaSub.Events():
 				b.linkChange(&changeDelta)
@@ -996,6 +1001,9 @@ var (
 )
 
 func (b *LocalBackend) onHealthChange(change health.Change) {
+	if !buildfeatures.HasHealth {
+		return
+	}
 	if change.WarnableChanged {
 		w := change.Warnable
 		us := change.UnhealthyState
@@ -6025,10 +6033,10 @@ func (b *LocalBackend) resolveExitNode() (changed bool) {
 //
 // b.mu must be held.
 func (b *LocalBackend) reconcilePrefsLocked(prefs *ipn.Prefs) (changed bool) {
-	if b.applySysPolicyLocked(prefs) {
+	if buildfeatures.HasSystemPolicy && b.applySysPolicyLocked(prefs) {
 		changed = true
 	}
-	if b.resolveExitNodeInPrefsLocked(prefs) {
+	if buildfeatures.HasUseExitNode && b.resolveExitNodeInPrefsLocked(prefs) {
 		changed = true
 	}
 	if changed {
@@ -6043,6 +6051,9 @@ func (b *LocalBackend) reconcilePrefsLocked(prefs *ipn.Prefs) (changed bool) {
 //
 // b.mu must be held.
 func (b *LocalBackend) resolveExitNodeInPrefsLocked(prefs *ipn.Prefs) (changed bool) {
+	if !buildfeatures.HasUseExitNode {
+		return false
+	}
 	if b.resolveAutoExitNodeLocked(prefs) {
 		changed = true
 	}
@@ -6338,6 +6349,9 @@ func peerAPIPorts(peer tailcfg.NodeView) (p4, p6 uint16) {
 }
 
 func (b *LocalBackend) CheckIPForwarding() error {
+	if !buildfeatures.HasAdvertiseRoutes {
+		return nil
+	}
 	if b.sys.IsNetstackRouter() {
 		return nil
 	}

ipn/localapi/localapi.go

@@ -72,15 +72,12 @@ var handler = map[string]LocalAPIHandler{
 	// The other /localapi/v0/NAME handlers are exact matches and contain only NAME
 	// without a trailing slash:
 	"alpha-set-device-attrs":       (*Handler).serveSetDeviceAttrs, // see tailscale/corp#24690
-	"check-ip-forwarding":          (*Handler).serveCheckIPForwarding,
 	"check-prefs":                  (*Handler).serveCheckPrefs,
 	"check-reverse-path-filtering": (*Handler).serveCheckReversePathFiltering,
 	"check-udp-gro-forwarding":     (*Handler).serveCheckUDPGROForwarding,
 	"derpmap":                      (*Handler).serveDERPMap,
 	"dial":                         (*Handler).serveDial,
 	"disconnect-control":           (*Handler).disconnectControl,
-	"dns-osconfig":                 (*Handler).serveDNSOSConfig,
-	"dns-query":                    (*Handler).serveDNSQuery,
 	"goroutines":                   (*Handler).serveGoroutines,
 	"handle-push-message":          (*Handler).serveHandlePushMessage,
 	"id-token":                     (*Handler).serveIDToken,
@@ -111,6 +108,9 @@ func init() {
 	if buildfeatures.HasAppConnectors {
 		Register("appc-route-info", (*Handler).serveGetAppcRouteInfo)
 	}
+	if buildfeatures.HasAdvertiseRoutes {
+		Register("check-ip-forwarding", (*Handler).serveCheckIPForwarding)
+	}
 	if buildfeatures.HasUseExitNode {
 		Register("suggest-exit-node", (*Handler).serveSuggestExitNode)
 		Register("set-use-exit-node-enabled", (*Handler).serveSetUseExitNodeEnabled)
@@ -122,6 +122,10 @@ func init() {
 		Register("bugreport", (*Handler).serveBugReport)
 		Register("pprof", (*Handler).servePprof)
 	}
+	if buildfeatures.HasDNS {
+		Register("dns-osconfig", (*Handler).serveDNSOSConfig)
+		Register("dns-query", (*Handler).serveDNSQuery)
+	}
 }
 
 // Register registers a new LocalAPI handler for the given name.

ipn/prefs.go

@@ -532,12 +532,16 @@ func (p *Prefs) Pretty() string { return p.pretty(runtime.GOOS) }
 func (p *Prefs) pretty(goos string) string {
 	var sb strings.Builder
 	sb.WriteString("Prefs{")
+	if buildfeatures.HasUseRoutes {
 		fmt.Fprintf(&sb, "ra=%v ", p.RouteAll)
+	}
+	if buildfeatures.HasDNS {
 		fmt.Fprintf(&sb, "dns=%v want=%v ", p.CorpDNS, p.WantRunning)
-	if p.RunSSH {
+	}
+	if buildfeatures.HasSSH && p.RunSSH {
 		sb.WriteString("ssh=true ")
 	}
-	if p.RunWebClient {
+	if buildfeatures.HasWebClient && p.RunWebClient {
 		sb.WriteString("webclient=true ")
 	}
 	if p.LoggedOut {
@@ -552,6 +556,7 @@ func (p *Prefs) pretty(goos string) string {
 	if p.ShieldsUp {
 		sb.WriteString("shields=true ")
 	}
+	if buildfeatures.HasUseExitNode {
 		if p.ExitNodeIP.IsValid() {
 			fmt.Fprintf(&sb, "exit=%v lan=%t ", p.ExitNodeIP, p.ExitNodeAllowLANAccess)
 		} else if !p.ExitNodeID.IsZero() {
@@ -560,6 +565,8 @@ func (p *Prefs) pretty(goos string) string {
 		if p.AutoExitNode.IsSet() {
 			fmt.Fprintf(&sb, "auto=%v ", p.AutoExitNode)
 		}
+	}
+	if buildfeatures.HasAdvertiseRoutes {
 		if len(p.AdvertiseRoutes) > 0 || goos == "linux" {
 			fmt.Fprintf(&sb, "routes=%v ", p.AdvertiseRoutes)
 		}
@@ -573,6 +580,7 @@ func (p *Prefs) pretty(goos string) string {
 			bb, _ := p.NoStatefulFiltering.Get()
 			fmt.Fprintf(&sb, "statefulFiltering=%v ", !bb)
 		}
+	}
 	if len(p.AdvertiseTags) > 0 {
 		fmt.Fprintf(&sb, "tags=%s ", strings.Join(p.AdvertiseTags, ","))
 	}
@@ -594,9 +602,13 @@ func (p *Prefs) pretty(goos string) string {
 	if p.NetfilterKind != "" {
 		fmt.Fprintf(&sb, "netfilterKind=%s ", p.NetfilterKind)
 	}
+	if buildfeatures.HasClientUpdate {
 		sb.WriteString(p.AutoUpdate.Pretty())
+	}
+	if buildfeatures.HasAppConnectors {
 		sb.WriteString(p.AppConnector.Pretty())
-	if p.RelayServerPort != nil {
+	}
+	if buildfeatures.HasRelayServer && p.RelayServerPort != nil {
 		fmt.Fprintf(&sb, "relayServerPort=%d ", *p.RelayServerPort)
 	}
 	if p.Persist != nil {