Close transport or listener just once

p2p/net/swarm/swarm.go

@@ -237,8 +237,14 @@ func (s *Swarm) close() {
 	s.transports.m = nil
 	s.transports.Unlock()
 
-	var wg sync.WaitGroup
+	// Dedup transports that may be listening on multiple protocols
+	transportsToClose := make(map[transport.Transport]struct{}, len(transports))
 	for _, t := range transports {
+		transportsToClose[t] = struct{}{}
+	}
+
+	var wg sync.WaitGroup
+	for t := range transportsToClose {
 		if closer, ok := t.(io.Closer); ok {
 			wg.Add(1)
 			go func(c io.Closer) {

p2p/net/swarm/swarm_listen.go

@@ -43,7 +43,7 @@ func (s *Swarm) Listen(addrs ...ma.Multiaddr) error {
 // and address with `/quic`, then the QUIC listener will close and also close
 // any `/quic-v1` address.
 func (s *Swarm) ListenClose(addrs ...ma.Multiaddr) {
-	var listenersToClose []transport.Listener
+	listenersToClose := make(map[transport.Listener]struct{}, len(addrs))
 
 	s.listeners.Lock()
 	for l := range s.listeners.m {
@@ -52,12 +52,12 @@ func (s *Swarm) ListenClose(addrs ...ma.Multiaddr) {
 		}
 
 		delete(s.listeners.m, l)
-		listenersToClose = append(listenersToClose, l)
+		listenersToClose[l] = struct{}{}
 	}
 	s.listeners.cacheEOL = time.Time{}
 	s.listeners.Unlock()
 
-	for _, l := range listenersToClose {
+	for l := range listenersToClose {
 		l.Close()
 	}
 }

p2p/transport/quic/transport.go

@@ -153,8 +153,6 @@ type transport struct {
 
 	connMx sync.Mutex
 	conns  map[quic.Connection]*conn
-
-	closeOnce sync.Once
 }
 
 var _ tpt.Transport = &transport{}
@@ -489,9 +487,5 @@ func (t *transport) String() string {
 }
 
 func (t *transport) Close() error {
-	// We may register multiple protocols, but they are all the same transport, so only support getting closed once.
-	t.closeOnce.Do(func() {
-		_ = t.connManager.Close()
-	})
-	return nil
+	return t.connManager.Close()
 }