webrtc receivebin: Don't unblock pad until sender is unblocked

As ther OpenSSL session is created when the receiver goes into
playing, we have to wait for the ICE session to be connected before we
can start delivering packets to the DTLS element.

Fixes #1599

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2363>

1 files changed, 27 insertions, 2 deletions

diff --git a/ext/webrtc/transportreceivebin.c b/ext/webrtc/transportreceivebin.c
index 786b0c2ba..6f826030b 100644
--- a/ext/webrtc/transportreceivebin.c
+++ b/ext/webrtc/transportreceivebin.c
@@ -112,13 +112,29 @@ void
 transport_receive_bin_set_receive_state (TransportReceiveBin * receive,
     ReceiveState state)
 {
+  GstWebRTCICEConnectionState icestate;
 
   g_mutex_lock (&receive->pad_block_lock);
   if (receive->receive_state != state) {
-    GST_DEBUG_OBJECT (receive, "changing receive state to %s",
+    GST_DEBUG_OBJECT (receive, "Requested change of receive state to %s",
         _receive_state_to_string (state));
   }
 
+  receive->receive_state = state;
+
+  g_object_get (receive->stream->transport->transport, "state", &icestate,
+      NULL);
+  if (state == RECEIVE_STATE_PASS) {
+    if (icestate == GST_WEBRTC_ICE_CONNECTION_STATE_CONNECTED ||
+        icestate == GST_WEBRTC_ICE_CONNECTION_STATE_COMPLETED) {
+      GST_LOG_OBJECT (receive, "Unblocking nicesrc because ICE is connected.");
+    } else {
+      GST_LOG_OBJECT (receive, "Can't unblock nicesrc yet because ICE "
+          "is not connected, it is %d", icestate);
+      state = RECEIVE_STATE_BLOCK;
+    }
+  }
+
   if (state == RECEIVE_STATE_PASS) {
     if (receive->rtp_block)
       _free_pad_block (receive->rtp_block);
@@ -151,11 +167,17 @@ transport_receive_bin_set_receive_state (TransportReceiveBin * receive,
       }
     }
   }
-  receive->receive_state = state;
   g_mutex_unlock (&receive->pad_block_lock);
 }
 
 static void
+_on_notify_ice_connection_state (GstWebRTCICETransport * transport,
+    GParamSpec * pspec, TransportReceiveBin * receive)
+{
+  transport_receive_bin_set_receive_state (receive, receive->receive_state);
+}
+
+static void
 transport_receive_bin_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
@@ -331,6 +353,9 @@ transport_receive_bin_constructed (GObject * object)
   gst_element_add_pad (GST_ELEMENT (receive), ghost);
   gst_object_unref (pad);
 
+  g_signal_connect_after (receive->stream->transport->transport,
+      "notify::state", G_CALLBACK (_on_notify_ice_connection_state), receive);
+
   G_OBJECT_CLASS (parent_class)->constructed (object);
 }