pass a conn that can be type asserted to a net.UDPConn to quic-go

p2p/transport/quic/listener.go

@@ -16,6 +16,8 @@ import (
 	ma "github.com/multiformats/go-multiaddr"
 )
 
+var quicListen = quic.Listen // so we can mock it in tests
+
 // A listener listens for QUIC connections.
 type listener struct {
 	quicListener   quic.Listener
@@ -38,7 +40,7 @@ func newListener(rconn *reuseConn, t *transport, localPeer peer.ID, key ic.PrivK
 		conf, _ := identity.ConfigForAny()
 		return conf, nil
 	}
-	ln, err := quic.Listen(rconn, &tlsConf, t.serverConfig)
+	ln, err := quicListen(rconn, &tlsConf, t.serverConfig)
 	if err != nil {
 		return nil, err
 	}

p2p/transport/quic/listener_test.go

@@ -3,18 +3,29 @@ package libp2pquic
 import (
 	"crypto/rand"
 	"crypto/rsa"
+	"crypto/tls"
 	"crypto/x509"
+	"errors"
 	"fmt"
 	"net"
+	"syscall"
 
 	ic "github.com/libp2p/go-libp2p-core/crypto"
 	tpt "github.com/libp2p/go-libp2p-core/transport"
+	quic "github.com/lucas-clemente/quic-go"
 
 	ma "github.com/multiformats/go-multiaddr"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 )
 
+// interface containing some methods defined on the net.UDPConn, but not the net.PacketConn
+type udpConn interface {
+	ReadFromUDP(b []byte) (int, *net.UDPAddr, error)
+	SetReadBuffer(bytes int) error
+	SyscallConn() (syscall.RawConn, error)
+}
+
 var _ = Describe("Listener", func() {
 	var t tpt.Transport
 
@@ -27,6 +38,25 @@ var _ = Describe("Listener", func() {
 		Expect(err).ToNot(HaveOccurred())
 	})
 
+	It("uses a conn that can interface assert to a UDPConn for listening", func() {
+		origQuicListen := quicListen
+		defer func() { quicListen = origQuicListen }()
+
+		var conn net.PacketConn
+		quicListen = func(c net.PacketConn, _ *tls.Config, _ *quic.Config) (quic.Listener, error) {
+			conn = c
+			return nil, errors.New("listen error")
+		}
+		localAddr, err := ma.NewMultiaddr("/ip4/127.0.0.1/udp/0/quic")
+		Expect(err).ToNot(HaveOccurred())
+		_, err = t.Listen(localAddr)
+		Expect(err).To(MatchError("listen error"))
+		Expect(conn).ToNot(BeNil())
+		defer conn.Close()
+		_, ok := conn.(udpConn)
+		Expect(ok).To(BeTrue())
+	})
+
 	Context("listening on the right address", func() {
 		It("returns the address it is listening on", func() {
 			localAddr, err := ma.NewMultiaddr("/ip4/127.0.0.1/udp/0/quic")

p2p/transport/quic/reuse.go

@@ -17,15 +17,15 @@ var (
 )
 
 type reuseConn struct {
-	net.PacketConn
+	*net.UDPConn
 
 	mutex       sync.Mutex
 	refCount    int
 	unusedSince time.Time
 }
 
-func newReuseConn(conn net.PacketConn, gater connmgr.ConnectionGater) *reuseConn {
-	return &reuseConn{PacketConn: conn}
+func newReuseConn(conn *net.UDPConn, gater connmgr.ConnectionGater) *reuseConn {
+	return &reuseConn{UDPConn: conn}
 }
 
 func (c *reuseConn) IncreaseCount() {

p2p/transport/quic/transport.go

@@ -27,6 +27,8 @@ import (
 
 var log = logging.Logger("quic-transport")
 
+var quicDialContext = quic.DialContext // so we can mock it in tests
+
 var quicConfig = &quic.Config{
 	MaxIncomingStreams:                    1000,
 	MaxIncomingUniStreams:                 -1,             // disable unidirectional streams
@@ -157,7 +159,7 @@ func (t *transport) Dial(ctx context.Context, raddr ma.Multiaddr, p peer.ID) (tp
 	if err != nil {
 		return nil, err
 	}
-	sess, err := quic.DialContext(ctx, pconn, addr, host, tlsConf, t.clientConfig)
+	sess, err := quicDialContext(ctx, pconn, addr, host, tlsConf, t.clientConfig)
 	if err != nil {
 		pconn.DecreaseCount()
 		return nil, err

p2p/transport/quic/transport_test.go

@@ -1,7 +1,17 @@
 package libp2pquic
 
 import (
+	"context"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"net"
+
+	ic "github.com/libp2p/go-libp2p-core/crypto"
 	tpt "github.com/libp2p/go-libp2p-core/transport"
+	quic "github.com/lucas-clemente/quic-go"
 	ma "github.com/multiformats/go-multiaddr"
 
 	. "github.com/onsi/ginkgo"
@@ -12,7 +22,12 @@ var _ = Describe("Transport", func() {
 	var t tpt.Transport
 
 	BeforeEach(func() {
-		t = &transport{}
+		rsaKey, err := rsa.GenerateKey(rand.Reader, 2048)
+		Expect(err).ToNot(HaveOccurred())
+		key, err := ic.UnmarshalRsaPrivateKey(x509.MarshalPKCS1PrivateKey(rsaKey))
+		Expect(err).ToNot(HaveOccurred())
+		t, err = NewTransport(key, nil, nil)
+		Expect(err).ToNot(HaveOccurred())
 	})
 
 	It("says if it can dial an address", func() {
@@ -35,4 +50,23 @@ var _ = Describe("Transport", func() {
 		Expect(protocols).To(HaveLen(1))
 		Expect(protocols[0]).To(Equal(ma.P_QUIC))
 	})
+
+	It("uses a conn that can interface assert to a UDPConn for dialing", func() {
+		origQuicDialContext := quicDialContext
+		defer func() { quicDialContext = origQuicDialContext }()
+
+		var conn net.PacketConn
+		quicDialContext = func(_ context.Context, c net.PacketConn, _ net.Addr, _ string, _ *tls.Config, _ *quic.Config) (quic.Session, error) {
+			conn = c
+			return nil, errors.New("listen error")
+		}
+		remoteAddr, err := ma.NewMultiaddr("/ip4/127.0.0.1/udp/0/quic")
+		Expect(err).ToNot(HaveOccurred())
+		_, err = t.Dial(context.Background(), remoteAddr, "remote peer id")
+		Expect(err).To(MatchError("listen error"))
+		Expect(conn).ToNot(BeNil())
+		defer conn.Close()
+		_, ok := conn.(udpConn)
+		Expect(ok).To(BeTrue())
+	})
 })