Use UDPConn wrapper instead of connected UDP

Fixes #270

association.go

@@ -264,6 +264,7 @@ func createClientWithContext(ctx context.Context, config Config) (*Association,
 	select {
 	case <-ctx.Done():
 		a.log.Errorf("[%s] client handshake canceled: state=%s", a.name, getAssociationStateString(a.getState()))
+		a.Close() // nolint:errcheck,gosec
 		return nil, ctx.Err()
 	case err := <-a.handshakeCompletedCh:
 		if err != nil {

association_test.go

@@ -2564,37 +2564,81 @@ func TestAssocMaxMessageSize(t *testing.T) {
 	})
 }
 
+// udpConnWrapper wraps a *net.UDPConn and implements net.Conn interface.
+type udpConnWrapper struct {
+	conn       *net.UDPConn
+	remoteAddr net.Addr
+}
+
+func newUDPConnWrapper(conn *net.UDPConn, remoteAddr net.Addr) net.Conn {
+	return &udpConnWrapper{
+		conn:       conn,
+		remoteAddr: remoteAddr,
+	}
+}
+
+// Implement the net.Conn interface methods
+func (w *udpConnWrapper) Read(b []byte) (n int, err error) {
+	// w.conn.ReadFrom(b)
+	n, _, err = w.conn.ReadFrom(b)
+	return n, err
+}
+
+func (w *udpConnWrapper) Write(b []byte) (n int, err error) {
+	return w.conn.WriteTo(b, w.remoteAddr)
+}
+
+func (w *udpConnWrapper) Close() error {
+	return w.conn.Close()
+}
+
+func (w *udpConnWrapper) LocalAddr() net.Addr {
+	return w.conn.LocalAddr()
+}
+
+func (w *udpConnWrapper) RemoteAddr() net.Addr {
+	return w.remoteAddr
+}
+
+func (w *udpConnWrapper) SetDeadline(t time.Time) error {
+	return w.conn.SetDeadline(t)
+}
+
+func (w *udpConnWrapper) SetReadDeadline(t time.Time) error {
+	return w.conn.SetReadDeadline(t)
+}
+
+func (w *udpConnWrapper) SetWriteDeadline(t time.Time) error {
+	return w.conn.SetWriteDeadline(t)
+}
+
 // crateUDPConnPair creates a pair of net.UDPConn objects that are connected with each other
-func createUDPConnPair(t *testing.T) (*net.UDPConn, *net.UDPConn, error) {
+func createUDPConnPair(t *testing.T) (net.Conn, net.Conn, error) {
 	udp1, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
 	if err != nil {
 		return nil, nil, err
 	}
 	addr1, ok := udp1.LocalAddr().(*net.UDPAddr)
 	require.True(t, ok)
-	err = udp1.Close()
-	require.NoError(t, err)
 
 	udp2, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.ParseIP("127.0.0.1")})
 	if err != nil {
 		return nil, nil, err
 	}
 	addr2, ok := udp2.LocalAddr().(*net.UDPAddr)
 	require.True(t, ok)
-	err = udp2.Close()
-	require.NoError(t, err)
 
-	udp1, err = net.DialUDP("udp", addr1, addr2)
+	conn1 := newUDPConnWrapper(udp1, addr2)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	udp2, err = net.DialUDP("udp", addr2, addr1)
+	conn2 := newUDPConnWrapper(udp2, addr1)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	return udp1, udp2, nil
+	return conn1, conn2, nil
 }
 
 func createAssocs(t *testing.T) (*Association, *Association, error) {
@@ -2952,3 +2996,64 @@ func TestAssociation_Abort(t *testing.T) {
 	assert.Equal(t, i, 0, "expected no data read")
 	assert.Error(t, err, "User Initiated Abort: 1234", "expected abort reason")
 }
+
+// TestAssociation_createClientWithContext tests that the client is closed when the context is canceled.
+func TestAssociation_createClientWithContext(t *testing.T) {
+	checkGoroutineLeaks(t)
+
+	udp1, udp2, err := createUDPConnPair(t)
+	require.NoError(t, err)
+
+	loggerFactory := logging.NewDefaultLoggerFactory()
+
+	errCh1 := make(chan error)
+	errCh2 := make(chan error)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+
+	go func() {
+		_, err2 := createClientWithContext(ctx, Config{
+			NetConn:       udp1,
+			LoggerFactory: loggerFactory,
+		})
+		if err2 != nil {
+			errCh1 <- err2
+		} else {
+			errCh1 <- nil
+		}
+	}()
+
+	go func() {
+		_, err2 := createClientWithContext(ctx, Config{
+			NetConn:       udp2,
+			LoggerFactory: loggerFactory,
+		})
+		if err2 != nil {
+			errCh2 <- err2
+		} else {
+			errCh2 <- nil
+		}
+	}()
+
+	// Cancel the context immediately
+	cancel()
+
+	var err1 error
+	var err2 error
+loop:
+	for {
+		select {
+		case err1 = <-errCh1:
+			if err1 != nil && err2 != nil {
+				break loop
+			}
+		case err2 = <-errCh2:
+			if err1 != nil && err2 != nil {
+				break loop
+			}
+		}
+	}
+
+	assert.Error(t, err1, "context canceled")
+	assert.Error(t, err2, "context canceled")
+}