net/tstun: add inner loop to poll
This avoids re-enqueuing to t.bufferConsumed,
which makes the code a bit clearer.
@@ -181,6 +181,16 @@ func (t *Wrapper) Close() error {
return err
}
+// isClosed reports whether t is closed.
+func (t *Wrapper) isClosed() bool {
+ select {
+ case <-t.closed:
+ return true
+ default:
+ return false
+ }
+}
+
// pumpEvents copies events from t.tdev to t.eventsUpDown and t.eventsOther.
// pumpEvents exits when t.tdev.events or t.closed is closed.
// pumpEvents closes t.eventsUpDown and t.eventsOther when it exits.
@@ -266,28 +276,24 @@ func allowSendOnClosedChannel() {
// so packets may be stuck in t.outbound if t.Read called t.tdev.Read directly.
func (t *Wrapper) poll() {
defer allowSendOnClosedChannel() // for send to t.outbound
- for {
- <-t.bufferConsumed
-
+ for range t.bufferConsumed {
+ var n int
+ var err error
// Read may use memory in t.buffer before PacketStartOffset for mandatory headers.
// This is the rationale behind the tun.Wrapper.{Read,Write} interfaces
// and the reason t.buffer has size MaxMessageSize and not MaxContentSize.
- n, err := t.tdev.Read(t.buffer[:], PacketStartOffset)
- if err != nil {
- t.outbound <- tunReadResult{err: err}
// In principle, read errors are not fatal (but wireguard-go disagrees).
- t.bufferConsumed <- struct{}{}
- continue
+ // We loop here until we get a non-empty (or failed) read.
+ // We don't need this loop for correctness,
+ // but wireguard-go will skip an empty read,
+ // so we might as well avoid the send through t.outbound.
+ for n == 0 && err == nil {
+ if t.isClosed() {
+ return
}
-
- // Wireguard will skip an empty read,
- // so we might as well do it here to avoid the send through t.outbound.
- if n == 0 {
- t.bufferConsumed <- struct{}{}
- continue
+ n, err = t.tdev.Read(t.buffer[:], PacketStartOffset)
}
-
- t.outbound <- tunReadResult{data: t.buffer[PacketStartOffset : PacketStartOffset+n]}
+ t.outbound <- tunReadResult{data: t.buffer[PacketStartOffset : PacketStartOffset+n], err: err}
}
}
