tailcfg: add Node.HasCap helpers

This makes a follow up change less noisy.

Updates #cleanup

Signed-off-by: Maisem Ali <maisem@tailscale.com>

cmd/tailscale/cli/funnel.go

@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"slices"
 	"strconv"
 	"strings"
 
@@ -147,15 +146,13 @@ func (e *serveEnv) runFunnel(ctx context.Context, args []string) error {
 //
 // verifyFunnelEnabled may refresh the local state and modify the st input.
 func (e *serveEnv) verifyFunnelEnabled(ctx context.Context, st *ipnstate.Status, port uint16) error {
-	hasFunnelAttrs := func(attrs []tailcfg.NodeCapability) bool {
-		hasHTTPS := slices.Contains(attrs, tailcfg.CapabilityHTTPS)
-		hasFunnel := slices.Contains(attrs, tailcfg.NodeAttrFunnel)
-		return hasHTTPS && hasFunnel
+	hasFunnelAttrs := func(selfNode *ipnstate.PeerStatus) bool {
+		return selfNode.HasCap(tailcfg.CapabilityHTTPS) && selfNode.HasCap(tailcfg.NodeAttrFunnel)
 	}
-	if hasFunnelAttrs(st.Self.Capabilities) {
+	if hasFunnelAttrs(st.Self) {
 		return nil // already enabled
 	}
-	enableErr := e.enableFeatureInteractive(ctx, "funnel", hasFunnelAttrs)
+	enableErr := e.enableFeatureInteractive(ctx, "funnel", tailcfg.CapabilityHTTPS, tailcfg.NodeAttrFunnel)
 	st, statusErr := e.getLocalClientStatusWithoutPeers(ctx) // get updated status; interactive flow may block
 	switch {
 	case statusErr != nil:

cmd/tailscale/cli/serve.go

@@ -18,7 +18,6 @@ import (
 	"path/filepath"
 	"reflect"
 	"runtime"
-	"slices"
 	"sort"
 	"strconv"
 	"strings"
@@ -269,9 +268,7 @@ func (e *serveEnv) runServe(ctx context.Context, args []string) error {
 		// on, enableFeatureInteractive will error. For now, we hide that
 		// error and maintain the previous behavior (prior to 2023-08-15)
 		// of letting them edit the serve config before enabling certs.
-		e.enableFeatureInteractive(ctx, "serve", func(caps []tailcfg.NodeCapability) bool {
-			return slices.Contains(caps, tailcfg.CapabilityHTTPS)
-		})
+		e.enableFeatureInteractive(ctx, "serve", tailcfg.CapabilityHTTPS)
 	}
 
 	srcPort, err := parseServePort(srcPortStr)
@@ -829,7 +826,7 @@ func parseServePort(s string) (uint16, error) {
 //
 // 2023-08-09: The only valid feature values are "serve" and "funnel".
 // This can be moved to some CLI lib when expanded past serve/funnel.
-func (e *serveEnv) enableFeatureInteractive(ctx context.Context, feature string, hasRequiredCapabilities func(caps []tailcfg.NodeCapability) bool) (err error) {
+func (e *serveEnv) enableFeatureInteractive(ctx context.Context, feature string, caps ...tailcfg.NodeCapability) (err error) {
 	info, err := e.lc.QueryFeature(ctx, feature)
 	if err != nil {
 		return err
@@ -875,7 +872,16 @@ func (e *serveEnv) enableFeatureInteractive(ctx context.Context, feature string,
 			return err
 		}
 		if nm := n.NetMap; nm != nil && nm.SelfNode.Valid() {
-			if hasRequiredCapabilities(nm.SelfNode.Capabilities().AsSlice()) {
+			gotAll := true
+			for _, c := range caps {
+				if !nm.SelfNode.HasCap(c) {
+					// The feature is not yet enabled.
+					// Continue blocking until it is.
+					gotAll = false
+					break
+				}
+			}
+			if gotAll {
 				e.lc.IncrementCounter(ctx, fmt.Sprintf("%s_enabled", feature), 1)
 				fmt.Fprintln(os.Stdout, "Success.")
 				return nil

cmd/tailscale/cli/serve_dev.go

@@ -15,7 +15,6 @@ import (
 	"os/signal"
 	"path"
 	"path/filepath"
-	"slices"
 	"sort"
 	"strconv"
 	"strings"
@@ -233,9 +232,7 @@ func (e *serveEnv) runServeCombined(subcmd serveMode) execFunc {
 			// on, enableFeatureInteractive will error. For now, we hide that
 			// error and maintain the previous behavior (prior to 2023-08-15)
 			// of letting them edit the serve config before enabling certs.
-			if err := e.enableFeatureInteractive(ctx, "serve", func(caps []tailcfg.NodeCapability) bool {
-				return slices.Contains(caps, tailcfg.CapabilityHTTPS)
-			}); err != nil {
+			if err := e.enableFeatureInteractive(ctx, "serve", tailcfg.CapabilityHTTPS); err != nil {
 				return fmt.Errorf("error enabling https feature: %w", err)
 			}
 		}

ipn/ipnlocal/local.go

@@ -4094,8 +4094,8 @@ func (b *LocalBackend) setNetInfo(ni *tailcfg.NetInfo) {
 }
 
 func hasCapability(nm *netmap.NetworkMap, cap tailcfg.NodeCapability) bool {
-	if nm != nil && nm.SelfNode.Valid() {
-		return views.SliceContains(nm.SelfNode.Capabilities(), cap)
+	if nm != nil {
+		return nm.SelfNode.HasCap(cap)
 	}
 	return false
 }

ipn/ipnlocal/peerapi.go

@@ -1035,7 +1035,7 @@ func (h *peerAPIHandler) canPutFile() bool {
 // canDebug reports whether h can debug this node (goroutines, metrics,
 // magicsock internal state, etc).
 func (h *peerAPIHandler) canDebug() bool {
-	if !views.SliceContains(h.selfNode.Capabilities(), tailcfg.CapabilityDebug) {
+	if !h.selfNode.HasCap(tailcfg.CapabilityDebug) {
 		// This node does not expose debug info.
 		return false
 	}

ipn/ipnstate/ipnstate.go

@@ -291,6 +291,11 @@ type PeerStatus struct {
 	Location *tailcfg.Location `json:",omitempty"`
 }
 
+// HasCap reports whether ps has the given capability.
+func (ps *PeerStatus) HasCap(cap tailcfg.NodeCapability) bool {
+	return slices.Contains(ps.Capabilities, cap)
+}
+
 // StatusBuilder is a request to construct a Status. A new StatusBuilder is
 // passed to various subsystems which then call methods on it to populate state.
 // Call its Status method to return the final constructed Status.

tailcfg/tailcfg.go

@@ -368,6 +368,16 @@ type Node struct {
 	ExitNodeDNSResolvers []*dnstype.Resolver `json:",omitempty"`
 }
 
+// HasCap reports whether the node has the given capability.
+func (v NodeView) HasCap(cap NodeCapability) bool {
+	return v.ж.HasCap(cap)
+}
+
+// HasCap reports whether the node has the given capability.
+func (v *Node) HasCap(cap NodeCapability) bool {
+	return v != nil && slices.Contains(v.Capabilities, cap)
+}
+
 // DisplayName returns the user-facing name for a node which should
 // be shown in client UIs.
 //

wgengine/wgcfg/nmcfg/nmcfg.go

@@ -15,7 +15,6 @@ import (
 	"tailscale.com/types/logger"
 	"tailscale.com/types/logid"
 	"tailscale.com/types/netmap"
-	"tailscale.com/types/views"
 	"tailscale.com/wgengine/wgcfg"
 )
 
@@ -63,7 +62,7 @@ func WGCfg(nm *netmap.NetworkMap, logf logger.Logf, flags netmap.WGConfigFlags,
 	// Setup log IDs for data plane audit logging.
 	if nm.SelfNode.Valid() {
 		cfg.NodeID = nm.SelfNode.StableID()
-		canNetworkLog := views.SliceContains(nm.SelfNode.Capabilities(), tailcfg.CapabilityDataPlaneAuditLogs)
+		canNetworkLog := nm.SelfNode.HasCap(tailcfg.CapabilityDataPlaneAuditLogs)
 		if canNetworkLog && nm.SelfNode.DataPlaneAuditLogID() != "" && nm.DomainAuditLogID != "" {
 			nodeID, errNode := logid.ParsePrivateID(nm.SelfNode.DataPlaneAuditLogID())
 			if errNode != nil {