fix: bound and configure tunnel quality probes (#533)

Closes #528 and #532.

go-backend/internal/http/handler/control_plane.go

@@ -59,6 +59,7 @@ type diagnosisWorkItem struct {
 type diagnosisExecOptions struct {
 	commandTimeout time.Duration
 	pingTimeoutMS  int
+	pingCount      int
 	timeoutMessage string
 }
 
@@ -1596,10 +1597,14 @@ func (h *Handler) tcpPingViaNode(nodeID int64, ip string, port int, options diag
 	if options.pingTimeoutMS <= 0 {
 		options.pingTimeoutMS = int(diagnosisCommandTimeout / time.Millisecond)
 	}
+	pingCount := options.pingCount
+	if pingCount <= 0 {
+		pingCount = 4
+	}
 	res, err := h.sendNodeCommandWithTimeout(nodeID, "TcpPing", map[string]interface{}{
 		"ip":      ip,
 		"port":    port,
-		"count":   4,
+		"count":   pingCount,
 		"timeout": options.pingTimeoutMS,
 	}, options.commandTimeout, false, false)
 	if err != nil {
@@ -1626,12 +1631,16 @@ func (h *Handler) tcpPingViaRemoteNode(node *nodeRecord, ip string, port int, op
 	if options.pingTimeoutMS <= 0 {
 		options.pingTimeoutMS = int(diagnosisCommandTimeout / time.Millisecond)
 	}
+	pingCount := options.pingCount
+	if pingCount <= 0 {
+		pingCount = 4
+	}
 
 	fc := client.NewFederationClientWithTimeout(options.commandTimeout)
 	return fc.Diagnose(remoteURL, remoteToken, h.federationLocalDomain(), client.RuntimeDiagnoseRequest{
 		IP:       strings.TrimSpace(ip),
 		Port:     port,
-		Count:    4,
+		Count:    pingCount,
 		Timeout:  options.pingTimeoutMS,
 		Protocol: "tcp",
 	})

go-backend/internal/http/handler/handler.go

@@ -1015,6 +1015,7 @@ func (h *Handler) updateConfigs(w http.ResponseWriter, r *http.Request) {
 			response.WriteJSON(w, response.Err(-2, err.Error()))
 			return
 		}
+		h.notifyTunnelQualityConfigChanged(key)
 	}
 
 	response.WriteJSON(w, response.OKEmpty())
@@ -1062,6 +1063,7 @@ func (h *Handler) updateSingleConfig(w http.ResponseWriter, r *http.Request) {
 		response.WriteJSON(w, response.Err(-2, err.Error()))
 		return
 	}
+	h.notifyTunnelQualityConfigChanged(name)
 
 	response.WriteJSON(w, response.OKEmpty())
 }
@@ -1110,11 +1112,23 @@ func normalizeAndValidateConfigValue(key, value string) (string, error) {
 		}
 	case monitoring.ConfigMonitorRetentionDays:
 		return monitoring.NormalizeMonitoringRetentionDays(value)
+	case monitoring.ConfigTunnelQualityProbeIntervalSec:
+		return monitoring.NormalizeTunnelQualityProbeIntervalSeconds(value)
 	default:
 		return value, nil
 	}
 }
 
+func (h *Handler) notifyTunnelQualityConfigChanged(key string) {
+	if h == nil || h.qualityProber == nil {
+		return
+	}
+	switch strings.TrimSpace(key) {
+	case monitorTunnelQualityEnabledConfigKey, monitoring.ConfigTunnelQualityProbeIntervalSec:
+		h.qualityProber.NotifyConfigChanged()
+	}
+}
+
 func (h *Handler) isTunnelQualityMonitoringEnabled() bool {
 	if h == nil || h.repo == nil {
 		return true

go-backend/internal/http/handler/tunnel_best_exit.go

@@ -152,7 +152,11 @@ func evaluateBestExitOwner(owner chainNodeRecord, exits []chainNodeRecord, nodes
 	ownerNode := nodes[owner.NodeID]
 	for _, exit := range exits {
 		exitNode := nodes[exit.NodeID]
-		if exitNode == nil {
+		if !isTunnelProbeNodeOnline(ownerNode) {
+			scores = append(scores, failedBestExitCandidate(owner.NodeID, exit, "owner node offline"))
+			continue
+		}
+		if !isTunnelProbeNodeOnline(exitNode) {
 			scores = append(scores, failedBestExitCandidate(owner.NodeID, exit, "exit node unavailable"))
 			continue
 		}

go-backend/internal/http/handler/tunnel_best_exit_test.go

@@ -358,9 +358,9 @@ func TestEvaluateBestExitOwnerScoresAllCandidates(t *testing.T) {
 		{NodeID: 31, NodeName: "exit-b", Port: 30031},
 	}
 	nodes := map[int64]*nodeRecord{
-		10: {ID: 10, ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10", TCPListenAddr: "[::]"},
-		30: {ID: 30, ServerIP: "10.0.0.30", ServerIPv4: "10.0.0.30", TCPListenAddr: "[::]"},
-		31: {ID: 31, ServerIP: "10.0.0.31", ServerIPv4: "10.0.0.31", TCPListenAddr: "[::]"},
+		10: {ID: 10, Status: 1, ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10", TCPListenAddr: "[::]"},
+		30: {ID: 30, Status: 1, ServerIP: "10.0.0.30", ServerIPv4: "10.0.0.30", TCPListenAddr: "[::]"},
+		31: {ID: 31, Status: 1, ServerIP: "10.0.0.31", ServerIPv4: "10.0.0.31", TCPListenAddr: "[::]"},
 	}
 	pinger := func(nodeID int64, ip string, port int, _ diagnosisExecOptions) (float64, float64, error) {
 		switch {
@@ -387,12 +387,30 @@ func TestEvaluateBestExitOwnerScoresAllCandidates(t *testing.T) {
 	}
 }
 
+func TestEvaluateBestExitOwnerSkipsOfflineCandidate(t *testing.T) {
+	owner := chainNodeRecord{NodeID: 10, NodeName: "entry"}
+	exits := []chainNodeRecord{{NodeID: 30, NodeName: "exit-a", Port: 30030}}
+	nodes := map[int64]*nodeRecord{
+		10: {ID: 10, Status: 1, ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10"},
+		30: {ID: 30, Status: 0, ServerIP: "10.0.0.30", ServerIPv4: "10.0.0.30"},
+	}
+	ping := func(nodeID int64, ip string, port int, options diagnosisExecOptions) (float64, float64, error) {
+		t.Fatalf("offline best-exit candidate should not be probed: node=%d target=%s:%d", nodeID, ip, port)
+		return 0, 100, nil
+	}
+
+	scores := evaluateBestExitOwner(owner, exits, nodes, "", diagnosisExecOptions{}, defaultTunnelProbeTarget(), ping)
+	if len(scores) != 1 || scores[0].Success {
+		t.Fatalf("expected one failed offline candidate, got %+v", scores)
+	}
+}
+
 func TestEvaluateBestExitOwnerUsesConfiguredPublicProbeTarget(t *testing.T) {
 	owner := chainNodeRecord{NodeID: 10, NodeName: "entry-a"}
 	exits := []chainNodeRecord{{NodeID: 30, NodeName: "exit-a", Port: 30001}}
 	nodes := map[int64]*nodeRecord{
-		10: {ID: 10, Name: "entry-a", ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10"},
-		30: {ID: 30, Name: "exit-a", ServerIP: "10.0.0.30", ServerIPv4: "10.0.0.30"},
+		10: {ID: 10, Name: "entry-a", Status: 1, ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10"},
+		30: {ID: 30, Name: "exit-a", Status: 1, ServerIP: "10.0.0.30", ServerIPv4: "10.0.0.30"},
 	}
 	target := tunnelProbeTarget{Host: "speed.example.com", Port: 8443}
 	var calls []string
@@ -419,8 +437,8 @@ func TestEvaluateBestExitOwnerMarksCandidateFailedWhenOwnerToExitFails(t *testin
 	owner := chainNodeRecord{NodeID: 10, NodeName: "entry"}
 	exits := []chainNodeRecord{{NodeID: 30, NodeName: "exit-a", Port: 30030}}
 	nodes := map[int64]*nodeRecord{
-		10: {ID: 10, ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10", TCPListenAddr: "[::]"},
-		30: {ID: 30, ServerIP: "10.0.0.30", ServerIPv4: "10.0.0.30", TCPListenAddr: "[::]"},
+		10: {ID: 10, Status: 1, ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10", TCPListenAddr: "[::]"},
+		30: {ID: 30, Status: 1, ServerIP: "10.0.0.30", ServerIPv4: "10.0.0.30", TCPListenAddr: "[::]"},
 	}
 	pinger := func(nodeID int64, ip string, port int, _ diagnosisExecOptions) (float64, float64, error) {
 		return 0, 100, errBestExitProbeForTest
@@ -436,8 +454,8 @@ func TestEvaluateBestExitOwnerMarksCandidateFailedWhenTargetResolutionFails(t *t
 	owner := chainNodeRecord{NodeID: 10, NodeName: "entry"}
 	exits := []chainNodeRecord{{NodeID: 30, NodeName: "exit-v6", Port: 30030}}
 	nodes := map[int64]*nodeRecord{
-		10: {ID: 10, Name: "entry", ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10", TCPListenAddr: "[::]"},
-		30: {ID: 30, Name: "exit-v6", ServerIP: "2001:db8::30", ServerIPv6: "2001:db8::30", TCPListenAddr: "[::]"},
+		10: {ID: 10, Name: "entry", Status: 1, ServerIP: "10.0.0.10", ServerIPv4: "10.0.0.10", TCPListenAddr: "[::]"},
+		30: {ID: 30, Name: "exit-v6", Status: 1, ServerIP: "2001:db8::30", ServerIPv6: "2001:db8::30", TCPListenAddr: "[::]"},
 	}
 	pinger := func(nodeID int64, ip string, port int, _ diagnosisExecOptions) (float64, float64, error) {
 		t.Fatalf("ping should not be called when target resolution fails: node=%d ip=%s port=%d", nodeID, ip, port)

go-backend/internal/http/handler/tunnel_quality_prober.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"log"
 	"sync"
 	"sync/atomic"
@@ -13,7 +14,6 @@ import (
 )
 
 const (
-	tunnelQualityProbeInterval  = 1 * time.Second
 	tunnelQualityProbeTimeout   = 8 * time.Second
 	tunnelQualityPingTimeoutMs  = 5000
 	tunnelQualityPruneInterval  = 10 * time.Minute
@@ -56,7 +56,7 @@ type tunnelQualityProber struct {
 	cache     sync.Map // tunnelID (int64) → *tunnelQualitySnapshot
 	ctx       context.Context
 	cancel    context.CancelFunc
-	interval  time.Duration
+	wake      chan struct{}
 	lastPrune int64
 	probing   int32 // atomic flag: 1 = probeAll running, 0 = idle
 	probeNode bestExitProbeFunc
@@ -65,8 +65,8 @@ type tunnelQualityProber struct {
 // newTunnelQualityProber creates a new prober (not yet running).
 func newTunnelQualityProber(h *Handler) *tunnelQualityProber {
 	return &tunnelQualityProber{
-		handler:  h,
-		interval: tunnelQualityProbeInterval,
+		handler: h,
+		wake:    make(chan struct{}, 1),
 	}
 }
 
@@ -86,6 +86,16 @@ func (p *tunnelQualityProber) Stop() {
 	p.cancel()
 }
 
+func (p *tunnelQualityProber) NotifyConfigChanged() {
+	if p == nil || p.wake == nil {
+		return
+	}
+	select {
+	case p.wake <- struct{}{}:
+	default:
+	}
+}
+
 // GetAll returns all cached quality snapshots (latest per tunnel).
 func (p *tunnelQualityProber) GetAll() []tunnelQualitySnapshot {
 	var items []tunnelQualitySnapshot
@@ -109,20 +119,44 @@ func (p *tunnelQualityProber) loop() {
 	// Run once immediately
 	p.probeAll()
 
-	ticker := time.NewTicker(p.interval)
-	defer ticker.Stop()
-
 	for {
+		timer := time.NewTimer(p.probeInterval())
 		select {
 		case <-p.ctx.Done():
+			stopAndDrainTunnelQualityTimer(timer)
 			return
-		case <-ticker.C:
+		case <-p.wake:
+			stopAndDrainTunnelQualityTimer(timer)
+			continue
+		case <-timer.C:
 			p.probeAll()
 			p.maybePrune()
 		}
 	}
 }
 
+func stopAndDrainTunnelQualityTimer(timer *time.Timer) {
+	if timer == nil || timer.Stop() {
+		return
+	}
+	select {
+	case <-timer.C:
+	default:
+	}
+}
+
+func (p *tunnelQualityProber) probeInterval() time.Duration {
+	if p == nil || p.handler == nil || p.handler.repo == nil {
+		return time.Duration(monitoring.DefaultTunnelQualityProbeIntervalSec) * time.Second
+	}
+	cfg, err := p.handler.repo.GetConfigsByNames([]string{monitoring.ConfigTunnelQualityProbeIntervalSec})
+	if err != nil {
+		return time.Duration(monitoring.DefaultTunnelQualityProbeIntervalSec) * time.Second
+	}
+	seconds := monitoring.TunnelQualityProbeIntervalSecondsFromConfigMap(cfg)
+	return time.Duration(seconds) * time.Second
+}
+
 func (p *tunnelQualityProber) isEnabled() bool {
 	if p == nil || p.handler == nil {
 		return true
@@ -246,15 +280,19 @@ func (p *tunnelQualityProber) probeTunnel(tunnelID int64) {
 	options := diagnosisExecOptions{
 		commandTimeout: tunnelQualityProbeTimeout,
 		pingTimeoutMS:  tunnelQualityPingTimeoutMs,
+		pingCount:      1,
 		timeoutMessage: "探测超时",
 	}
 	p.probeBestExitOwners(tunnelID, inNodes, midNodesGrouped, outNodes, ipPreference, options, probeTarget)
 
+	entry, _, entryOnline := p.firstOnlineChainNode(inNodes)
+	exit, _, exitOnline := p.firstOnlineChainNode(outNodes)
+
 	switch tunnel.Type {
 	case 1:
 		// Port forwarding: entry → public probe target only.
-		if len(inNodes) > 0 {
-			lat, loss, err := p.pingNode(inNodes[0].NodeID, probeTarget.Host, probeTarget.Port, options)
+		if entryOnline {
+			lat, loss, err := p.pingNode(entry.NodeID, probeTarget.Host, probeTarget.Port, options)
 			if err == nil {
 				snap.ExitToBingLatency = lat
 				snap.ExitToBingLoss = loss
@@ -262,24 +300,42 @@ func (p *tunnelQualityProber) probeTunnel(tunnelID int64) {
 			} else {
 				snap.ErrorMessage = err.Error()
 			}
+		} else {
+			snap.ErrorMessage = "入口节点均不在线"
 		}
 	case 2:
 		// Tunnel forwarding: entry → exit + exit → Bing
 		probeOK := true
 
-		if len(inNodes) > 0 && len(outNodes) > 0 {
+		if !entryOnline {
+			probeOK = false
+			snap.ErrorMessage = "入口节点均不在线"
+			snap.EntryToExitLatency = -1
+			snap.EntryToExitLoss = 100
+		} else if !exitOnline {
+			probeOK = false
+			snap.ErrorMessage = "出口节点均不在线"
+			snap.EntryToExitLatency = -1
+			snap.EntryToExitLoss = 100
+		} else {
 			var hops []TunnelQualityHop
 			var totalLat float64
 			remainingSuccessProb := 1.0
 
 			nodesInPath := make([]chainNodeRecord, 0, 2+len(midNodesGrouped))
-			nodesInPath = append(nodesInPath, inNodes[0])
+			nodesInPath = append(nodesInPath, entry)
 			for _, midGroup := range midNodesGrouped {
-				if len(midGroup) > 0 {
-					nodesInPath = append(nodesInPath, midGroup[0])
+				mid, _, online := p.firstOnlineChainNode(midGroup)
+				if !online {
+					probeOK = false
+					snap.ErrorMessage = "中间节点组均不在线"
+					break
 				}
+				nodesInPath = append(nodesInPath, mid)
+			}
+			if probeOK {
+				nodesInPath = append(nodesInPath, exit)
 			}
-			nodesInPath = append(nodesInPath, outNodes[0])
 
 			for i := 0; i < len(nodesInPath)-1; i++ {
 				source := nodesInPath[i]
@@ -293,7 +349,7 @@ func (p *tunnelQualityProber) probeTunnel(tunnelID int64) {
 				}
 
 				targetNode, nodeErr := h.getNodeRecord(target.NodeID)
-				if nodeErr != nil || targetNode == nil {
+				if nodeErr != nil || !isTunnelProbeNodeOnline(targetNode) {
 					snap.ErrorMessage = "节点 " + target.NodeName + " 不可用"
 					probeOK = false
 					hop.Latency = -1
@@ -351,8 +407,8 @@ func (p *tunnelQualityProber) probeTunnel(tunnelID int64) {
 		}
 
 		// Exit → Bing
-		if len(outNodes) > 0 {
-			lat, loss, err := p.pingNode(outNodes[0].NodeID, probeTarget.Host, probeTarget.Port, options)
+		if exitOnline {
+			lat, loss, err := p.pingNode(exit.NodeID, probeTarget.Host, probeTarget.Port, options)
 			if err == nil {
 				snap.ExitToBingLatency = lat
 				snap.ExitToBingLoss = loss
@@ -367,8 +423,8 @@ func (p *tunnelQualityProber) probeTunnel(tunnelID int64) {
 		snap.Success = probeOK
 	default:
 		// Unknown type: entry → public probe target.
-		if len(inNodes) > 0 {
-			lat, loss, err := p.pingNode(inNodes[0].NodeID, probeTarget.Host, probeTarget.Port, options)
+		if entryOnline {
+			lat, loss, err := p.pingNode(entry.NodeID, probeTarget.Host, probeTarget.Port, options)
 			if err == nil {
 				snap.ExitToBingLatency = lat
 				snap.ExitToBingLoss = loss
@@ -376,12 +432,31 @@ func (p *tunnelQualityProber) probeTunnel(tunnelID int64) {
 			} else {
 				snap.ErrorMessage = err.Error()
 			}
+		} else {
+			snap.ErrorMessage = "入口节点均不在线"
 		}
 	}
 
 	p.storeResult(snap)
 }
 
+func isTunnelProbeNodeOnline(node *nodeRecord) bool {
+	return node != nil && (node.IsRemote == 1 || node.Status == 1)
+}
+
+func (p *tunnelQualityProber) firstOnlineChainNode(nodes []chainNodeRecord) (chainNodeRecord, *nodeRecord, bool) {
+	if p == nil || p.handler == nil {
+		return chainNodeRecord{}, nil, false
+	}
+	for _, candidate := range nodes {
+		node, err := p.handler.getNodeRecord(candidate.NodeID)
+		if err == nil && isTunnelProbeNodeOnline(node) {
+			return candidate, node, true
+		}
+	}
+	return chainNodeRecord{}, nil, false
+}
+
 func (p *tunnelQualityProber) probeBestExitOwners(tunnelID int64, inNodes []chainNodeRecord, chainHops [][]chainNodeRecord, outNodes []chainNodeRecord, ipPreference string, options diagnosisExecOptions, probeTarget tunnelProbeTarget) {
 	if p == nil || p.handler == nil || p.handler.bestExit == nil || len(outNodes) <= 1 {
 		return
@@ -444,6 +519,9 @@ func (p *tunnelQualityProber) tcpPingNode(nodeID int64, ip string, port int, opt
 	if nodeErr != nil {
 		return 0, 100, nodeErr
 	}
+	if !isTunnelProbeNodeOnline(node) {
+		return 0, 100, errors.New("节点不在线")
+	}
 
 	var pingData map[string]interface{}
 	var pingErr error

go-backend/internal/http/handler/tunnel_quality_prober_test.go

@@ -26,6 +26,9 @@ func TestTunnelQualityProberUsesConfiguredProbeTarget(t *testing.T) {
 	p := newTunnelQualityProber(h)
 	var calls []string
 	p.probeNode = func(nodeID int64, ip string, port int, options diagnosisExecOptions) (float64, float64, error) {
+		if options.pingCount != 1 {
+			t.Fatalf("expected real-time quality probe count 1, got %d", options.pingCount)
+		}
 		calls = append(calls, fmt.Sprintf("%d|%s|%d", nodeID, ip, port))
 		return 10, 0, nil
 	}
@@ -46,6 +49,63 @@ func TestTunnelQualityProberUsesConfiguredProbeTarget(t *testing.T) {
 	}
 }
 
+func TestTunnelQualityProberSkipsAllOfflineExits(t *testing.T) {
+	h := setupProbeTargetTunnelHandler(t)
+	seedQualityForwardTunnel(t, h, 81, []int{0, 0, 0})
+
+	p := newTunnelQualityProber(h)
+	probeCalls := 0
+	p.probeNode = func(nodeID int64, ip string, port int, options diagnosisExecOptions) (float64, float64, error) {
+		probeCalls++
+		return 0, 100, fmt.Errorf("unexpected probe node=%d target=%s:%d", nodeID, ip, port)
+	}
+	p.probeTunnel(81)
+
+	if probeCalls != 0 {
+		t.Fatalf("expected no TCP probes when all exits are offline, got %d", probeCalls)
+	}
+	snaps := p.GetAll()
+	if len(snaps) != 1 {
+		t.Fatalf("expected one quality snapshot, got %+v", snaps)
+	}
+	if snaps[0].Success || snaps[0].ErrorMessage != "出口节点均不在线" {
+		t.Fatalf("expected offline exit snapshot, got %+v", snaps[0])
+	}
+	if snaps[0].EntryToExitLoss != 100 {
+		t.Fatalf("expected 100%% entry-to-exit loss, got %+v", snaps[0])
+	}
+}
+
+func TestTunnelQualityProberUsesOnlineBackupExit(t *testing.T) {
+	h := setupProbeTargetTunnelHandler(t)
+	seedQualityForwardTunnel(t, h, 82, []int{0, 1})
+
+	p := newTunnelQualityProber(h)
+	var calls []string
+	p.probeNode = func(nodeID int64, ip string, port int, options diagnosisExecOptions) (float64, float64, error) {
+		if options.pingCount != 1 {
+			t.Fatalf("expected real-time quality probe count 1, got %d", options.pingCount)
+		}
+		calls = append(calls, fmt.Sprintf("%d|%s|%d", nodeID, ip, port))
+		return 10, 0, nil
+	}
+	p.probeTunnel(82)
+
+	if slices.Contains(calls, "10|10.0.0.30|30030") {
+		t.Fatalf("did not expect probe to offline primary exit, calls=%+v", calls)
+	}
+	if !slices.Contains(calls, "10|10.0.0.31|30031") {
+		t.Fatalf("expected entry probe to online backup exit, calls=%+v", calls)
+	}
+	if !slices.Contains(calls, "31|www.bing.com|443") {
+		t.Fatalf("expected public probe from online backup exit, calls=%+v", calls)
+	}
+	snaps := p.GetAll()
+	if len(snaps) != 1 || !snaps[0].Success {
+		t.Fatalf("expected successful backup exit snapshot, got %+v", snaps)
+	}
+}
+
 func TestTunnelQualityProberStoresProbeTargetWhenChainIncomplete(t *testing.T) {
 	h := setupProbeTargetTunnelHandler(t)
 	seedProbeTargetTunnel(t, h, 78, "quality-target-incomplete", "speed.example.com", 8443)
@@ -67,3 +127,69 @@ func TestTunnelQualityProberStoresProbeTargetWhenChainIncomplete(t *testing.T) {
 		t.Fatalf("unexpected snapshot target metadata: %+v", snaps[0])
 	}
 }
+
+func TestTunnelQualityProberUsesConfiguredInterval(t *testing.T) {
+	h := setupProbeTargetTunnelHandler(t)
+	if err := h.repo.UpsertConfig("monitor_tunnel_quality_interval_sec", "15", time.Now().UnixMilli()); err != nil {
+		t.Fatalf("upsert interval config: %v", err)
+	}
+
+	p := newTunnelQualityProber(h)
+	if got := p.probeInterval(); got != 15*time.Second {
+		t.Fatalf("probe interval = %s, want 15s", got)
+	}
+}
+
+func TestTunnelQualityProberConfigNotificationIsCoalesced(t *testing.T) {
+	p := newTunnelQualityProber(nil)
+	p.NotifyConfigChanged()
+	p.NotifyConfigChanged()
+
+	if got := len(p.wake); got != 1 {
+		t.Fatalf("wake notifications = %d, want 1", got)
+	}
+}
+
+func TestNormalizeTunnelQualityProbeIntervalConfigValue(t *testing.T) {
+	got, err := normalizeAndValidateConfigValue("monitor_tunnel_quality_interval_sec", " 15 ")
+	if err != nil || got != "15" {
+		t.Fatalf("normalize interval = %q, %v", got, err)
+	}
+	if _, err := normalizeAndValidateConfigValue("monitor_tunnel_quality_interval_sec", "0"); err == nil {
+		t.Fatalf("expected invalid interval to be rejected")
+	}
+}
+
+func seedQualityForwardTunnel(t *testing.T, h *Handler, tunnelID int64, exitStatuses []int) {
+	t.Helper()
+	now := time.Now().UnixMilli()
+	if err := h.repo.DB().Exec(`
+		INSERT INTO tunnel(id, name, traffic_ratio, type, protocol, flow, created_time, updated_time, status, inx, ip_preference, probe_target_host, probe_target_port)
+		VALUES(?, ?, 1, 2, 'tls', 1, ?, ?, 1, ?, '', '', 0)
+	`, tunnelID, fmt.Sprintf("quality-forward-%d", tunnelID), now, now, tunnelID).Error; err != nil {
+		t.Fatalf("insert forwarding tunnel: %v", err)
+	}
+	if err := h.repo.DB().Exec(`
+		INSERT INTO chain_tunnel(tunnel_id, chain_type, node_id, port, strategy, inx, protocol)
+		VALUES(?, '1', 10, 30001, 'fifo', 1, 'tls')
+	`, tunnelID).Error; err != nil {
+		t.Fatalf("insert entry chain: %v", err)
+	}
+	for i, status := range exitStatuses {
+		nodeID := int64(30 + i)
+		port := 30030 + i
+		ip := fmt.Sprintf("10.0.0.%d", nodeID)
+		if err := h.repo.DB().Exec(`
+			INSERT INTO node(id, name, secret, server_ip, server_ip_v4, server_ip_v6, port, interface_name, version, http, tls, socks, created_time, updated_time, status, tcp_listen_addr, udp_listen_addr, inx)
+			VALUES(?, ?, ?, ?, ?, '', '30000-30100', '', 'v1', 1, 1, 1, ?, ?, ?, '[::]', '[::]', 0)
+		`, nodeID, fmt.Sprintf("exit-%d", i+1), fmt.Sprintf("exit-secret-%d", i+1), ip, ip, now, now, status).Error; err != nil {
+			t.Fatalf("insert exit node %d: %v", nodeID, err)
+		}
+		if err := h.repo.DB().Exec(`
+			INSERT INTO chain_tunnel(tunnel_id, chain_type, node_id, port, strategy, inx, protocol)
+			VALUES(?, '3', ?, ?, 'fifo', ?, 'tls')
+		`, tunnelID, nodeID, port, i+1).Error; err != nil {
+			t.Fatalf("insert exit chain %d: %v", nodeID, err)
+		}
+	}
+}