checkpt

overlay/tun_disabled.go

@@ -25,39 +25,21 @@ type disabledTun struct {
 	numReaders int
 }
 
-// disabledQueue is one tio.Queue view onto a shared disabledTun. Each queue
-// owns a private batchRet so concurrent Read calls from different reader
-// goroutines do not race on the returned slice.
-type disabledQueue struct {
-	parent   *disabledTun
-	batchRet [1]tio.Packet
-}
-
-func (q *disabledQueue) Read() ([]tio.Packet, error) {
-	r, ok := <-q.parent.read
+// Read hands the next queued packet to a reader, copying it into b. Reads
+// from concurrent queues are safe: the channel receive serializes them and
+// each queue copies into its own private scratch buffer.
+func (t *disabledTun) Read(b []byte) (int, error) {
+	r, ok := <-t.read
 	if !ok {
-		return nil, io.EOF
+		return 0, io.EOF
 	}
 
-	q.parent.tx.Inc(1)
-	if q.parent.l.Enabled(context.Background(), slog.LevelDebug) {
-		q.parent.l.Debug("Write payload", "raw", prettyPacket(r))
+	t.tx.Inc(1)
+	if t.l.Enabled(context.Background(), slog.LevelDebug) {
+		t.l.Debug("Write payload", "raw", prettyPacket(r))
 	}
 
-	q.batchRet[0] = tio.Packet{Bytes: r}
-	return q.batchRet[:], nil
-}
-
-// Write on a queue forwards to the underlying disabledTun. All queues share
-// one ICMP-handling/log path so this is a thin pass-through.
-func (q *disabledQueue) Write(b []byte) (int, error) {
-	return q.parent.Write(b)
-}
-
-// Close on a queue is a no-op. The shared channel and metrics are owned by
-// the disabledTun; Close on the device tears them down once for everybody.
-func (q *disabledQueue) Close() error {
-	return nil
+	return copy(b, r), nil
 }
 
 func newDisabledTun(vpnNetworks []netip.Prefix, queueLen int, metricsEnabled bool, l *slog.Logger) *disabledTun {
@@ -138,7 +120,9 @@ func (t *disabledTun) NewMultiQueueReader() error {
 func (t *disabledTun) Readers() []tio.Queue {
 	out := make([]tio.Queue, t.numReaders)
 	for i := range t.numReaders {
-		out[i] = &disabledQueue{parent: t}
+		// NoClose: the shared channel and metrics are owned by the
+		// disabledTun; Close on the device tears them down once for everybody.
+		out[i] = tio.NewSingleQueueNoClose(t, defaultBatchBufSize)
 	}
 	return out
 }