state: consolidate route-election and node helpers

hscontrol/state/debug.go

@@ -62,51 +62,23 @@ type DebugStringInfo struct {
 
 // DebugOverview returns a comprehensive overview of the current state for debugging.
 func (s *State) DebugOverview() string {
-	allNodes := s.nodeStore.ListNodes()
-	users, _ := s.ListAllUsers()
+	info := s.DebugOverviewJSON()
 
 	var sb strings.Builder
 
 	sb.WriteString("=== Headscale State Overview ===\n\n")
 
 	// Node statistics
-	fmt.Fprintf(&sb, "Nodes: %d total\n", allNodes.Len())
-
-	userNodeCounts := make(map[string]int)
-	onlineCount := 0
-	expiredCount := 0
-	ephemeralCount := 0
-
-	now := time.Now()
-
-	for _, node := range allNodes.All() {
-		if node.Valid() {
-			userName := node.Owner().Name()
-			userNodeCounts[userName]++
-
-			if node.IsOnline().Valid() && node.IsOnline().Get() {
-				onlineCount++
-			}
-
-			if node.Expiry().Valid() && node.Expiry().Get().Before(now) {
-				expiredCount++
-			}
-
-			if node.AuthKey().Valid() && node.AuthKey().Ephemeral() {
-				ephemeralCount++
-			}
-		}
-	}
-
-	fmt.Fprintf(&sb, "  - Online: %d\n", onlineCount)
-	fmt.Fprintf(&sb, "  - Expired: %d\n", expiredCount)
-	fmt.Fprintf(&sb, "  - Ephemeral: %d\n", ephemeralCount)
+	fmt.Fprintf(&sb, "Nodes: %d total\n", info.Nodes.Total)
+	fmt.Fprintf(&sb, "  - Online: %d\n", info.Nodes.Online)
+	fmt.Fprintf(&sb, "  - Expired: %d\n", info.Nodes.Expired)
+	fmt.Fprintf(&sb, "  - Ephemeral: %d\n", info.Nodes.Ephemeral)
 	sb.WriteString("\n")
 
 	// User statistics
-	fmt.Fprintf(&sb, "Users: %d total\n", len(users))
+	fmt.Fprintf(&sb, "Users: %d total\n", info.TotalUsers)
 
-	for userName, nodeCount := range userNodeCounts {
+	for userName, nodeCount := range info.Users {
 		fmt.Fprintf(&sb, "  - %s: %d nodes\n", userName, nodeCount)
 	}
 
@@ -114,18 +86,17 @@ func (s *State) DebugOverview() string {
 
 	// Policy information
 	sb.WriteString("Policy:\n")
-	fmt.Fprintf(&sb, "  - Mode: %s\n", s.cfg.Policy.Mode)
+	fmt.Fprintf(&sb, "  - Mode: %s\n", info.Policy.Mode)
 
-	if s.cfg.Policy.Mode == types.PolicyModeFile {
-		fmt.Fprintf(&sb, "  - Path: %s\n", s.cfg.Policy.Path)
+	if info.Policy.Mode == string(types.PolicyModeFile) {
+		fmt.Fprintf(&sb, "  - Path: %s\n", info.Policy.Path)
 	}
 
 	sb.WriteString("\n")
 
 	// DERP information
-	derpMap := s.derpMap.Load()
-	if derpMap != nil {
-		fmt.Fprintf(&sb, "DERP: %d regions configured\n", len(derpMap.Regions))
+	if info.DERP.Configured {
+		fmt.Fprintf(&sb, "DERP: %d regions configured\n", info.DERP.Regions)
 	} else {
 		sb.WriteString("DERP: not configured\n")
 	}
@@ -133,14 +104,7 @@ func (s *State) DebugOverview() string {
 	sb.WriteString("\n")
 
 	// Route information
-	primaryStr := s.PrimaryRoutesString()
-
-	routeCount := len(strings.Split(strings.TrimSpace(primaryStr), "\n"))
-	if primaryStr == "" {
-		routeCount = 0
-	}
-
-	fmt.Fprintf(&sb, "Primary Routes: %d active\n", routeCount)
+	fmt.Fprintf(&sb, "Primary Routes: %d active\n", info.PrimaryRoutes)
 	sb.WriteString("\n")
 
 	// Registration cache
@@ -371,14 +335,7 @@ func (s *State) DebugOverviewJSON() DebugOverviewInfo {
 	}
 
 	// Route information
-	primaryStr := s.PrimaryRoutesString()
-
-	routeCount := len(strings.Split(strings.TrimSpace(primaryStr), "\n"))
-	if primaryStr == "" {
-		routeCount = 0
-	}
-
-	info.PrimaryRoutes = routeCount
+	info.PrimaryRoutes = len(s.nodeStore.PrimaryRoutes())
 
 	return info
 }

hscontrol/state/ha_health.go

@@ -74,16 +74,24 @@ func (p *HAHealthProber) ProbeOnce(
 ) {
 	haNodes := p.state.nodeStore.HANodes()
 
-	// Drop stable-session entries for nodes that are no longer HA
-	// candidates so a future reappearance starts fresh.
+	// Build the deduplicated node-ID set and slice in one pass.
+	var nodeIDs []types.NodeID
+
 	seen := make(set.Set[types.NodeID])
 
 	for _, nodes := range haNodes {
 		for _, id := range nodes {
+			if seen.Contains(id) {
+				continue
+			}
+
 			seen.Add(id)
+			nodeIDs = append(nodeIDs, id)
 		}
 	}
 
+	// Drop stable-session entries for nodes that are no longer HA
+	// candidates so a future reappearance starts fresh.
 	p.lastStableSession.Range(func(id types.NodeID, _ uint64) bool {
 		if !seen.Contains(id) {
 			p.lastStableSession.Delete(id)
@@ -96,20 +104,6 @@ func (p *HAHealthProber) ProbeOnce(
 		return
 	}
 
-	// Deduplicate node IDs across prefixes.
-	var nodeIDs []types.NodeID
-
-	dedup := make(set.Set[types.NodeID])
-
-	for _, nodes := range haNodes {
-		for _, id := range nodes {
-			if !dedup.Contains(id) {
-				dedup.Add(id)
-				nodeIDs = append(nodeIDs, id)
-			}
-		}
-	}
-
 	log.Debug().
 		Int("haNodes", len(nodeIDs)).
 		Msg("HA health prober starting probe cycle")

hscontrol/state/node_store.go

@@ -527,33 +527,24 @@ func (s *NodeStore) applyBatch(batch []work) {
 	// Update node count gauge
 	nodeStoreNodesCount.Set(float64(len(nodes)))
 
-	// Send the resulting nodes to all work items that requested them
+	// Send the resulting nodes to all work items that requested them.
+	// A zero-value NodeView{} reports Valid()==false, matching node.View()
+	// for a node that was deleted or never existed.
 	for nodeID, workItems := range nodeResultRequests {
+		var nodeView types.NodeView
 		if node, exists := nodes[nodeID]; exists {
-			nodeView := node.View()
-			for _, w := range workItems {
-				w.nodeResult <- nodeView
+			nodeView = node.View()
+		}
 
-				close(w.nodeResult)
+		for _, w := range workItems {
+			w.nodeResult <- nodeView
 
-				if w.errResult != nil {
-					w.errResult <- setErrResults[w]
+			close(w.nodeResult)
 
-					close(w.errResult)
-				}
-			}
-		} else {
-			// Node was deleted or doesn't exist
-			for _, w := range workItems {
-				w.nodeResult <- types.NodeView{} // Send invalid view
+			if w.errResult != nil {
+				w.errResult <- setErrResults[w]
 
-				close(w.nodeResult)
-
-				if w.errResult != nil {
-					w.errResult <- setErrResults[w]
-
-					close(w.errResult)
-				}
+				close(w.errResult)
 			}
 		}
 	}
@@ -669,26 +660,13 @@ func snapshotFromNodes(
 	return newSnap
 }
 
-// electPrimaryRoutes picks the primary advertiser for each non-exit
-// prefix. Inputs are restricted to online nodes that advertise the
-// prefix. The previous primary is preserved when it is still online
-// and healthy (anti-flap); otherwise the lowest-NodeID healthy
-// advertiser wins. When every advertiser is unhealthy the previous
-// primary is preserved only if still a candidate — falling back to
-// any other candidate would point peers at a node the prober has
-// already declared unreachable, so leaving the prefix unmapped is
-// preferred until a probe cycle finds one that responds.
-func electPrimaryRoutes(
+// onlineAdvertisers maps each non-exit prefix to the IDs of online nodes
+// that approve it. Nodes are visited in the order of ids, so the per-prefix
+// slices preserve that order.
+func onlineAdvertisers(
 	nodes map[types.NodeID]types.Node,
-	prev map[netip.Prefix]types.NodeID,
-) (map[netip.Prefix]types.NodeID, map[types.NodeID]bool) {
-	ids := make([]types.NodeID, 0, len(nodes))
-	for id := range nodes {
-		ids = append(ids, id)
-	}
-
-	slices.Sort(ids)
-
+	ids []types.NodeID,
+) map[netip.Prefix][]types.NodeID {
 	advertisers := make(map[netip.Prefix][]types.NodeID)
 
 	for _, id := range ids {
@@ -706,6 +684,24 @@ func electPrimaryRoutes(
 		}
 	}
 
+	return advertisers
+}
+
+// electPrimaryRoutes picks the primary advertiser for each non-exit
+// prefix. Inputs are restricted to online nodes that advertise the
+// prefix. The previous primary is preserved when it is still online
+// and healthy (anti-flap); otherwise the lowest-NodeID healthy
+// advertiser wins. When every advertiser is unhealthy the previous
+// primary is preserved only if still a candidate — falling back to
+// any other candidate would point peers at a node the prober has
+// already declared unreachable, so leaving the prefix unmapped is
+// preferred until a probe cycle finds one that responds.
+func electPrimaryRoutes(
+	nodes map[types.NodeID]types.Node,
+	prev map[netip.Prefix]types.NodeID,
+) (map[netip.Prefix]types.NodeID, map[types.NodeID]bool) {
+	advertisers := onlineAdvertisers(nodes, slices.Sorted(maps.Keys(nodes)))
+
 	routes := make(map[netip.Prefix]types.NodeID, len(advertisers))
 	for prefix, candidates := range advertisers {
 		if cur, ok := prev[prefix]; ok &&
@@ -734,7 +730,7 @@ func electPrimaryRoutes(
 		// would point peers at a node the prober has already declared
 		// unreachable; leaving the prefix unmapped is honest until a
 		// probe cycle picks one that responds.
-		if !found && len(candidates) >= 1 {
+		if !found {
 			if cur, ok := prev[prefix]; ok && slices.Contains(candidates, cur) {
 				selected = cur
 				found = true
@@ -919,21 +915,10 @@ func (s *NodeStore) PrimaryRoutesForNode(id types.NodeID) []netip.Prefix {
 func (s *NodeStore) HANodes() map[netip.Prefix][]types.NodeID {
 	snap := s.data.Load()
 
-	advertisers := make(map[netip.Prefix][]types.NodeID)
-
-	for id, n := range snap.nodesByID {
-		if n.IsOnline == nil || !*n.IsOnline {
-			continue
-		}
-
-		for _, p := range n.AllApprovedRoutes() {
-			if tsaddr.IsExitRoute(p) {
-				continue
-			}
-
-			advertisers[p] = append(advertisers[p], id)
-		}
-	}
+	advertisers := onlineAdvertisers(
+		snap.nodesByID,
+		slices.Sorted(maps.Keys(snap.nodesByID)),
+	)
 
 	out := make(map[netip.Prefix][]types.NodeID)
 
@@ -942,7 +927,6 @@ func (s *NodeStore) HANodes() map[netip.Prefix][]types.NodeID {
 			continue
 		}
 
-		slices.Sort(ids)
 		out[p] = ids
 	}
 

hscontrol/state/state.go

@@ -771,6 +771,16 @@ func (s *State) ResolveNode(query string) (types.NodeView, bool) {
 		return s.GetNodeByID(id)
 	}
 
+	// keepLowest returns whichever node has the lower ID, so repeated
+	// calls resolve deterministically across snapshot iterations.
+	keepLowest := func(cur, cand types.NodeView) types.NodeView {
+		if !cur.Valid() || cand.ID() < cur.ID() {
+			return cand
+		}
+
+		return cur
+	}
+
 	// Try IP address.
 	addr, addrErr := netip.ParseAddr(query)
 	if addrErr == nil {
@@ -781,9 +791,7 @@ func (s *State) ResolveNode(query string) (types.NodeView, bool) {
 				continue
 			}
 
-			if !match.Valid() || n.ID() < match.ID() {
-				match = n
-			}
+			match = keepLowest(match, n)
 		}
 
 		return match, match.Valid()
@@ -795,13 +803,9 @@ func (s *State) ResolveNode(query string) (types.NodeView, bool) {
 
 	for _, n := range s.ListNodes().All() {
 		if n.GivenName() == query {
-			if !givenMatch.Valid() || n.ID() < givenMatch.ID() {
-				givenMatch = n
-			}
+			givenMatch = keepLowest(givenMatch, n)
 		} else if n.Hostname() == query {
-			if !hostMatch.Valid() || n.ID() < hostMatch.ID() {
-				hostMatch = n
-			}
+			hostMatch = keepLowest(hostMatch, n)
 		}
 	}