Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/server/middleware/ingress_reject_access_sampler.go

@@ -0,0 +1,58 @@
+package middleware
+
+import (
+	"sync"
+	"time"
+)
+
+const (
+	ingressRejectAccessLogLimit       = 20
+	ingressRejectAccessLogWindow      = time.Second
+	ingressRejectDroppedSummaryPeriod = 30 * time.Second
+)
+
+type ingressRejectAccessSampler struct {
+	mu            sync.Mutex
+	limit         int
+	window        time.Duration
+	summaryPeriod time.Duration
+	windowStart   time.Time
+	emitted       int
+	dropped       uint64
+	lastSummary   time.Time
+}
+
+func newIngressRejectAccessSampler(limit int, window, summaryPeriod time.Duration) *ingressRejectAccessSampler {
+	return &ingressRejectAccessSampler{limit: limit, window: window, summaryPeriod: summaryPeriod}
+}
+
+// allow applies one process-wide fixed-window budget. It stores no attacker
+// dimensions, so memory remains constant even for rotating keys and addresses.
+func (s *ingressRejectAccessSampler) allow(now time.Time) (allowed bool, droppedSummary uint64) {
+	if s == nil || s.limit <= 0 || s.window <= 0 {
+		return false, 0
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.windowStart.IsZero() || now.Sub(s.windowStart) >= s.window || now.Before(s.windowStart) {
+		s.windowStart = now
+		s.emitted = 0
+	}
+	if s.emitted < s.limit {
+		s.emitted++
+		return true, 0
+	}
+	s.dropped++
+	if s.summaryPeriod > 0 && (s.lastSummary.IsZero() || now.Sub(s.lastSummary) >= s.summaryPeriod) {
+		droppedSummary = s.dropped
+		s.dropped = 0
+		s.lastSummary = now
+	}
+	return false, droppedSummary
+}
+
+var globalIngressRejectAccessSampler = newIngressRejectAccessSampler(
+	ingressRejectAccessLogLimit,
+	ingressRejectAccessLogWindow,
+	ingressRejectDroppedSummaryPeriod,
+)