feat(tcp, udp): implement stream state release after verdict and adjust flush interval logic

engine/worker.go

@@ -20,9 +20,18 @@ const (
 	defaultTCPTimeout                       = 10 * time.Minute
 	defaultUDPMaxStreams                    = 4096
 
-	tcpFlushInterval = 1 * time.Minute
+	// 超时 flush 的间隔范围。判定后的流走 connmark 旁路，FIN 到不了用户态，
+	// 只能靠定时 flush 把它们从连接池里清掉。间隔取超时的一半：
+	// 之前固定 1 分钟，30 秒的超时实际会让流在池里活到 90 秒。
+	tcpMaxFlushInterval = 1 * time.Minute
+	tcpMinFlushInterval = 1 * time.Second
 )
 
+// tcpFlushIntervalFor 返回给定 TCP 超时下的 flush 间隔
+func tcpFlushIntervalFor(timeout time.Duration) time.Duration {
+	return min(tcpMaxFlushInterval, max(timeout/2, tcpMinFlushInterval))
+}
+
 type workerPacket struct {
 	StreamID   uint32
 	Packet     gopacket.Packet
@@ -122,7 +131,7 @@ func (w *worker) Run(ctx context.Context) {
 	w.logger.WorkerStart(w.id)
 	defer w.logger.WorkerStop(w.id)
 
-	tcpFlushTicker := time.NewTicker(tcpFlushInterval)
+	tcpFlushTicker := time.NewTicker(tcpFlushIntervalFor(w.tcpTimeout))
 	defer tcpFlushTicker.Stop()
 
 	for {