Fix connection success cache cleanup

Pass the cleanup interval through as the time.Duration supplied by callers. Multiplying it by time.Second overflows realistic duration values and prevents expired destination attempts from being removed from memory.\n\nAdd coverage for physical cache eviction so logical expiration cannot hide retained entries.

Committed-By-Agent: codex
Co-authored-by: codex <noreply@openai.com>

Author: shubh-stripe

pkg/smokescreen/conntrack/conn_tracker.go

@@ -65,7 +65,7 @@ type ConnSuccessRateStats struct {
 // - cleanupInterval is how often expired items (e.g., items older than the calculationWindow) will be deleted from memory.
 func StartNewConnSuccessRateTracker(calculationInterval time.Duration, calculationWindow time.Duration, cleanupInterval time.Duration, statsc metrics.MetricsClientInterface) *ConnSuccessRateTracker {
 	newSuccessTracker := &ConnSuccessRateTracker{
-		ConnAttempts: cache.New(calculationWindow, time.Second*cleanupInterval),
+		ConnAttempts: cache.New(calculationWindow, cleanupInterval),
 	}
 	newSuccessTracker.ConnSuccessRateStats.Store(ConnSuccessRateStats{CalculatedAt: time.Now(), ConnSuccessRate: 100, TotalConns: 0})
 

pkg/smokescreen/conntrack/conn_tracker_test.go

@@ -113,6 +113,29 @@ func TestConnSuccessRateTracker(t *testing.T) {
 	}
 }
 
+func TestConnSuccessRateTrackerDeletesExpiredAttempts(t *testing.T) {
+	sd := atomic.Value{}
+	sd.Store(false)
+	tracker := NewTracker(
+		time.Second,
+		metrics.NewNoOpMetricsClient(),
+		logrus.New(),
+		sd,
+		StartNewConnSuccessRateTracker(
+			time.Hour,
+			50*time.Millisecond,
+			10*time.Millisecond,
+			metrics.NewNoOpMetricsClient(),
+		),
+	)
+
+	tracker.RecordAttempt("example.com", true)
+	assert.Equal(t, 1, tracker.SuccessRateTracker.ConnAttempts.ItemCount())
+	assert.Eventually(t, func() bool {
+		return tracker.SuccessRateTracker.ConnAttempts.ItemCount() == 0
+	}, time.Second, 10*time.Millisecond)
+}
+
 func TestNoConnSuccessRateTracker(t *testing.T) {
 	assert := assert.New(t)
 	tracker := NewTestTracker(time.Second)