Judge loss by arrival order and a deadline, one tx ring per stream

rx.go

@@ -116,7 +116,6 @@ type rxWorker struct {
 	spec   *frameSpec
 	stats  *rxStats
 	loss   *lossWindow
-	masked *atomic.Bool
 	ready  *sync.WaitGroup
 }
 
@@ -133,10 +132,6 @@ func (w *rxWorker) run(done *atomic.Bool) {
 	w.ready.Done()
 
 	for !done.Load() {
-		// The worker just counts; the mask gate above decides what a masked
-		// tick's counts are worth. One flag load covers the batch for the loss
-		// window, whose gap charges outlive the tick they happened in.
-		masked := w.masked.Load()
 		n, err := recvmmsg(w.fd, hdrs, unix.MSG_WAITFORONE)
 		if n <= 0 {
 			if err != nil && err != unix.EAGAIN && err != unix.EINTR {
@@ -161,12 +156,12 @@ func (w *rxWorker) run(done *atomic.Bool) {
 			bytes += uint64(len(buf))
 
 			// The ethertype this socket is bound to already says which stream the
-			// frame belongs to, so a header naming another one is damaged, as is a
-			// sequence number the sender never reached.
-			if p.stream != w.stream || !w.loss.observe(p.seq, masked) {
+			// frame belongs to, so a header naming another one is damaged.
+			if p.stream != w.stream {
 				w.stats.badHdr.Add(1)
 				continue
 			}
+			w.loss.observe(p.seq)
 
 			want, ok := w.spec.expectedCRC(p.patIdx, p.payLen)
 			if !ok {