From b9dfe1b310eaa7f0e2d02bb928447d05ccfd6c94 Mon Sep 17 00:00:00 2001
From: aler9 <46489434+aler9@users.noreply.github.com>
Date: Wed, 20 Jan 2021 23:23:35 +0100
Subject: [PATCH] client: support servers which don't provide UDP ports (#21)

---
 clientconf.go      | 13 +++++++++----
 clientconf_test.go | 37 +++++++++++++++++++++++++++++++++++--
 clientconn.go      |  8 +++++---
 clientconnudpl.go  |  2 +-
 4 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/clientconf.go b/clientconf.go
index 1a35f3b8..751a06e2 100644
--- a/clientconf.go
+++ b/clientconf.go
@@ -39,6 +39,15 @@ type ClientConf struct {
 	// It defaults to &tls.Config{InsecureSkipVerify:true}
 	TLSConfig *tls.Config
 
+	// disable being redirected to other servers, that can happen during Describe().
+	// It defaults to false.
+	RedirectDisable bool
+
+	// enable communication with servers which don't provide server ports.
+	// this can be a security issue.
+	// It defaults to false.
+	AnyPortEnable bool
+
 	// timeout of read operations.
 	// It defaults to 10 seconds.
 	ReadTimeout time.Duration
@@ -47,10 +56,6 @@ type ClientConf struct {
 	// It defaults to 10 seconds.
 	WriteTimeout time.Duration
 
-	// disable being redirected to other servers, that can happen during Describe().
-	// It defaults to false.
-	RedirectDisable bool
-
 	// read buffer count.
 	// If greater than 1, allows to pass buffers to routines different than the one
 	// that is reading frames.
diff --git a/clientconf_test.go b/clientconf_test.go
index 02d58919..1c36197b 100644
--- a/clientconf_test.go
+++ b/clientconf_test.go
@@ -220,10 +220,43 @@ func TestClientDialReadZeroServerPorts(t *testing.T) {
 			},
 		}.Write(bconn.Writer)
 		require.NoError(t, err)
+
+		err = req.Read(bconn.Reader)
+		require.NoError(t, err)
+		require.Equal(t, base.Play, req.Method)
+
+		err = base.Response{
+			StatusCode: base.StatusOK,
+		}.Write(bconn.Writer)
+		require.NoError(t, err)
+
+		time.Sleep(1 * time.Second)
+
+		l1, err := net.ListenPacket("udp", "localhost:0")
+		require.NoError(t, err)
+		defer l1.Close()
+
+		l1.WriteTo([]byte("\x00\x00\x00\x00"), &net.UDPAddr{
+			IP:   net.ParseIP("127.0.0.1"),
+			Port: th.ClientPorts[0],
+		})
 	}()
 
-	_, err = DialRead("rtsp://localhost:8554/teststream")
-	require.Equal(t, "server ports are zero", err.Error())
+	conf := ClientConf{
+		AnyPortEnable: true,
+	}
+
+	conn, err := conf.DialRead("rtsp://localhost:8554/teststream")
+	require.NoError(t, err)
+
+	frameRecv := make(chan struct{})
+	done := conn.ReadFrames(func(id int, typ StreamType, payload []byte) {
+		close(frameRecv)
+	})
+
+	<-frameRecv
+	conn.Close()
+	<-done
 }
 
 func TestClientDialReadAutomaticProtocol(t *testing.T) {
diff --git a/clientconn.go b/clientconn.go
index 5c1868f3..745bac7f 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -578,7 +578,7 @@ func (c *ClientConn) Setup(mode headers.TransportMode, track *Track,
 		if thRes.ServerPorts == nil {
 			rtpListener.close()
 			rtcpListener.close()
-			return nil, fmt.Errorf("server ports not provided")
+			return nil, fmt.Errorf("server ports have not been provided. Use AnyPortEnable to communicate with this server")
 		}
 
 		if (thRes.ServerPorts[0] == 0 && thRes.ServerPorts[1] != 0) ||
@@ -588,8 +588,10 @@ func (c *ClientConn) Setup(mode headers.TransportMode, track *Track,
 			return nil, fmt.Errorf("server ports must be both zero or both not zero")
 		}
 
-		if thRes.ServerPorts[0] == 0 && thRes.ServerPorts[1] == 0 {
-			return nil, fmt.Errorf("server ports are zero")
+		if !c.conf.AnyPortEnable {
+			if thRes.ServerPorts[0] == 0 && thRes.ServerPorts[1] == 0 {
+				return nil, fmt.Errorf("server ports have not been provided. Use AnyPortEnable to communicate with this server")
+			}
 		}
 
 	} else {
diff --git a/clientconnudpl.go b/clientconnudpl.go
index 559a4118..84e63fd4 100644
--- a/clientconnudpl.go
+++ b/clientconnudpl.go
@@ -79,7 +79,7 @@ func (l *clientConnUDPListener) run() {
 
 		uaddr := addr.(*net.UDPAddr)
 
-		if !l.remoteIP.Equal(uaddr.IP) || l.remotePort != uaddr.Port {
+		if !l.remoteIP.Equal(uaddr.IP) || (l.remotePort != 0 && l.remotePort != uaddr.Port) {
 			continue
 		}