ipn/ipnlocal, types/netmap: replace hasCapability with set lookup on NetworkMap

When node attributes were super rare, the O(n) slice scans looking for
node attributes was more acceptable. But now more code and more users
are using increasingly more node attributes. Time to make it a map.

Noticed while working on tailscale/corp#17879

Updates #cleanup

Change-Id: Ic17c80341f418421002fbceb47490729048756d2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

control/controlclient/map.go

@@ -31,6 +31,7 @@
 	"tailscale.com/types/views"
 	"tailscale.com/util/clientmetric"
 	"tailscale.com/util/mak"
+	"tailscale.com/util/set"
 	"tailscale.com/wgengine/filter"
 )
 
@@ -74,6 +75,7 @@ type mapSession struct {
 	// Fields storing state over the course of multiple MapResponses.
 	lastPrintMap           time.Time
 	lastNode               tailcfg.NodeView
+	lastCapSet             set.Set[tailcfg.NodeCapability]
 	peers                  map[tailcfg.NodeID]*tailcfg.NodeView // pointer to view (oddly). same pointers as sortedPeers.
 	sortedPeers            []*tailcfg.NodeView                  // same pointers as peers, but sorted by Node.ID
 	lastDNSConfig          *tailcfg.DNSConfig
@@ -239,6 +241,15 @@ func (ms *mapSession) updateStateFromResponse(resp *tailcfg.MapResponse) {
 
 	if resp.Node != nil {
 		ms.lastNode = resp.Node.View()
+
+		capSet := set.Set[tailcfg.NodeCapability]{}
+		for _, c := range resp.Node.Capabilities {
+			capSet.Add(c)
+		}
+		for c := range resp.Node.CapMap {
+			capSet.Add(c)
+		}
+		ms.lastCapSet = capSet
 	}
 
 	for _, up := range resp.UserProfiles {
@@ -803,6 +814,7 @@ func (ms *mapSession) netmap() *netmap.NetworkMap {
 		nm.SelfNode = node
 		nm.Expiry = node.KeyExpiry()
 		nm.Name = node.Name()
+		nm.AllCaps = ms.lastCapSet
 	}
 
 	ms.addUserProfile(nm, nm.User())

ipn/ipnlocal/local.go

@@ -1164,7 +1164,7 @@ func (b *LocalBackend) SetControlClientStatus(c controlclient.Client, st control
 
 	// Perform all reconfiguration based on the netmap here.
 	if st.NetMap != nil {
-		b.capTailnetLock = hasCapability(st.NetMap, tailcfg.CapabilityTailnetLock)
+		b.capTailnetLock = st.NetMap.HasCap(tailcfg.CapabilityTailnetLock)
 		b.setWebClientAtomicBoolLocked(st.NetMap)
 
 		b.mu.Unlock() // respect locking rules for tkaSyncIfNeeded
@@ -1201,7 +1201,7 @@ func (b *LocalBackend) SetControlClientStatus(c controlclient.Client, st control
 	}
 
 	if st.NetMap != nil {
-		if envknob.NoLogsNoSupport() && hasCapability(st.NetMap, tailcfg.CapabilityDataPlaneAuditLogs) {
+		if envknob.NoLogsNoSupport() && st.NetMap.HasCap(tailcfg.CapabilityDataPlaneAuditLogs) {
 			msg := "tailnet requires logging to be enabled. Remove --no-logs-no-support from tailscaled command line."
 			health.SetLocalLogConfigHealth(errors.New(msg))
 			// Connecting to this tailnet without logging is forbidden; boot us outta here.
@@ -3068,7 +3068,7 @@ func (b *LocalBackend) checkSSHPrefsLocked(p *ipn.Prefs) error {
 		return nil
 	}
 	if b.netMap != nil {
-		if !hasCapability(b.netMap, tailcfg.CapabilitySSH) {
+		if !b.netMap.HasCap(tailcfg.CapabilitySSH) {
 			if b.isDefaultServerLocked() {
 				return errors.New("Unable to enable local Tailscale SSH server; not enabled on Tailnet. See https://tailscale.com/s/ssh")
 			}
@@ -3093,9 +3093,8 @@ func (b *LocalBackend) sshOnButUnusableHealthCheckMessageLocked() (healthMessage
 		return ""
 	}
 	isDefault := b.isDefaultServerLocked()
-	isAdmin := hasCapability(nm, tailcfg.CapabilityAdmin)
 
-	if !isAdmin {
+	if !nm.HasCap(tailcfg.CapabilityAdmin) {
 		return healthmsg.TailscaleSSHOnBut + "access controls don't allow anyone to access this device. Ask your admin to update your tailnet's ACLs to allow access."
 	}
 	if !isDefault {
@@ -3565,7 +3564,7 @@ func (b *LocalBackend) authReconfig() {
 	prefs := b.pm.CurrentPrefs()
 	nm := b.netMap
 	hasPAC := b.prevIfState.HasPAC()
-	disableSubnetsIfPAC := hasCapability(nm, tailcfg.NodeAttrDisableSubnetsIfPAC)
+	disableSubnetsIfPAC := nm.HasCap(tailcfg.NodeAttrDisableSubnetsIfPAC)
 	dohURL, dohURLOK := exitNodeCanProxyDNS(nm, b.peers, prefs.ExitNodeID())
 	dcfg := dnsConfigForNetmap(nm, b.peers, prefs, b.logf, version.OS())
 	// If the current node is an app connector, ensure the app connector machine is started
@@ -4533,7 +4532,7 @@ func (b *LocalBackend) ShouldExposeRemoteWebClient() bool {
 //
 // b.mu must be held.
 func (b *LocalBackend) setWebClientAtomicBoolLocked(nm *netmap.NetworkMap) {
-	shouldRun := !hasCapability(nm, tailcfg.NodeAttrDisableWebClient)
+	shouldRun := !nm.HasCap(tailcfg.NodeAttrDisableWebClient)
 	wasRunning := b.webClientAtomicBool.Swap(shouldRun)
 	if wasRunning && !shouldRun {
 		go b.webClientShutdown() // stop web client
@@ -4630,13 +4629,6 @@ func (b *LocalBackend) setNetInfo(ni *tailcfg.NetInfo) {
 	cc.SetNetInfo(ni)
 }
 
-func hasCapability(nm *netmap.NetworkMap, cap tailcfg.NodeCapability) bool {
-	if nm != nil {
-		return nm.SelfNode.HasCap(cap)
-	}
-	return false
-}
-
 // setNetMapLocked updates the LocalBackend state to reflect the newly
 // received nm. If nm is nil, it resets all configuration as though
 // Tailscale is turned off.
@@ -4665,15 +4657,15 @@ func (b *LocalBackend) setNetMapLocked(nm *netmap.NetworkMap) {
 	}
 
 	// Determine if file sharing is enabled
-	fs := hasCapability(nm, tailcfg.CapabilityFileSharing)
+	fs := nm.HasCap(tailcfg.CapabilityFileSharing)
 	if fs != b.capFileSharing {
 		osshare.SetFileSharingEnabled(fs, b.logf)
 	}
 	b.capFileSharing = fs
 
-	if hasCapability(nm, tailcfg.NodeAttrLinuxMustUseIPTables) {
+	if nm.HasCap(tailcfg.NodeAttrLinuxMustUseIPTables) {
 		b.capForcedNetfilter = "iptables"
-	} else if hasCapability(nm, tailcfg.NodeAttrLinuxMustUseNfTables) {
+	} else if nm.HasCap(tailcfg.NodeAttrLinuxMustUseNfTables) {
 		b.capForcedNetfilter = "nftables"
 	} else {
 		b.capForcedNetfilter = "" // empty string means client can auto-detect
@@ -4685,8 +4677,8 @@ func (b *LocalBackend) setNetMapLocked(nm *netmap.NetworkMap) {
 	b.setDebugLogsByCapabilityLocked(nm)
 
 	// See the netns package for documentation on what this capability does.
-	netns.SetBindToInterfaceByRoute(hasCapability(nm, tailcfg.CapabilityBindToInterfaceByRoute))
+	netns.SetBindToInterfaceByRoute(nm.HasCap(tailcfg.CapabilityBindToInterfaceByRoute))
-	netns.SetDisableBindConnToInterface(hasCapability(nm, tailcfg.CapabilityDebugDisableBindConnToInterface))
+	netns.SetDisableBindConnToInterface(nm.HasCap(tailcfg.CapabilityDebugDisableBindConnToInterface))
 
 	b.setTCPPortsInterceptedFromNetmapAndPrefsLocked(b.pm.CurrentPrefs())
 	if nm == nil {
@@ -4777,7 +4769,7 @@ func (t *tailFSTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 func (b *LocalBackend) setDebugLogsByCapabilityLocked(nm *netmap.NetworkMap) {
 	// These are sufficiently cheap (atomic bools) that we don't need to
 	// store state and compare.
-	if hasCapability(nm, tailcfg.CapabilityDebugTSDNSResolution) {
+	if nm.HasCap(tailcfg.CapabilityDebugTSDNSResolution) {
 		dnscache.SetDebugLoggingEnabled(true)
 	} else {
 		dnscache.SetDebugLoggingEnabled(false)

types/netmap/netmap.go

@@ -17,6 +17,7 @@
 	"tailscale.com/tka"
 	"tailscale.com/types/key"
 	"tailscale.com/types/views"
+	"tailscale.com/util/set"
 	"tailscale.com/wgengine/filter"
 )
 
@@ -26,6 +27,7 @@
 // alias parts of previous NetworkMap values.
 type NetworkMap struct {
 	SelfNode   tailcfg.NodeView
+	AllCaps    set.Set[tailcfg.NodeCapability] // set version of SelfNode.Capabilities + SelfNode.CapMap
 	NodeKey    key.NodePublic
 	PrivateKey key.NodePrivate
 	Expiry     time.Time
@@ -120,6 +122,11 @@ func (nm *NetworkMap) GetMachineStatus() tailcfg.MachineStatus {
 	return tailcfg.MachineUnauthorized
 }
 
+// HasCap reports whether nm is non-nil and nm.AllCaps contains c.
+func (nm *NetworkMap) HasCap(c tailcfg.NodeCapability) bool {
+	return nm != nil && nm.AllCaps.Contains(c)
+}
+
 // PeerByTailscaleIP returns a peer's Node based on its Tailscale IP.
 //
 // If nm is nil or no peer is found, ok is false.