add log for debugging

p2p/test/basichost/basic_host_test.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"strings"
-	"sync"
 	"testing"
 	"time"
 
@@ -235,6 +234,7 @@ func TestWebRTCWithQUICManyConnections(t *testing.T) {
 		libp2p.Transport(libp2pwebrtc.New),
 		libp2p.ListenAddrStrings("/ip4/0.0.0.0/udp/0/quic-v1"),
 		libp2p.ListenAddrStrings("/ip4/0.0.0.0/udp/0/webrtc-direct"),
+		libp2p.ResourceManager(&network.NullResourceManager{}),
 	)
 	require.NoError(t, err)
 	defer h.Close()
@@ -252,24 +252,15 @@ func TestWebRTCWithQUICManyConnections(t *testing.T) {
 	require.NoError(t, err)
 	defer d.Close()
 
-	startDial := make(chan struct{})
-	var wg sync.WaitGroup
-	wg.Add(N)
 	for i := 0; i < N; i++ {
-		go func() {
-			defer wg.Done()
-			<-startDial
-			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-			defer cancel()
-			// With happy eyeballs these dialers will connect over only /quic-v1
-			// and not stall the /webrtc-direct handshake goroutines.
-			// it is fine if the dial fails, we just want to ensure that there's space
-			// in the /webrtc-direct listen queue
-			_ = dialers[i].Connect(ctx, peer.AddrInfo{ID: h.ID(), Addrs: h.Addrs()})
-		}()
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		// With happy eyeballs these dialers will connect over only /quic-v1
+		// and not stall the /webrtc-direct handshake goroutines.
+		// it is fine if the dial fails, we just want to ensure that there's space
+		// in the /webrtc-direct listen queue
+		_ = dialers[i].Connect(ctx, peer.AddrInfo{ID: h.ID(), Addrs: h.Addrs()})
 	}
-	close(startDial)
-	wg.Wait()
 
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()

p2p/transport/webrtc/listener.go

@@ -38,7 +38,7 @@ const (
 	// sending the initial connection request message(STUN Binding request). Such peers take up a goroutine
 	// till connection timeout. As the number of handshakes in parallel is still guarded by the resource
 	// manager, this higher number is okay.
-	DefaultMaxInFlightConnections = 128
+	DefaultMaxInFlightConnections = 10
 )
 
 type listener struct {
@@ -126,7 +126,7 @@ func (l *listener) listen() {
 			}
 			return
 		}
-
+		fmt.Println("pending handshakes", len(inFlightSemaphore))
 		go func() {
 			defer func() { <-inFlightSemaphore }()
 

p2p/transport/webrtc/transport.go

@@ -293,6 +293,8 @@ func (t *WebRTCTransport) dial(ctx context.Context, scope network.ConnManagement
 		return nil, fmt.Errorf("resolve udp address: %w", err)
 	}
 
+	fmt.Println("dialing", remoteMultiaddr)
+
 	// Instead of encoding the local fingerprint we
 	// generate a random UUID as the connection ufrag.
 	// The only requirement here is that the ufrag and password