WebRTC DTLS handsake quick connection

src/gst-plugins/webrtcendpoint/kmswebrtcbundleconnection.c

@@ -92,7 +92,7 @@ kms_webrtc_bundle_connection_add (KmsIRtpConnection * base_rtp_conn,
   KmsWebRtcBundleConnectionPrivate *priv = self->priv;
   KmsWebRtcTransport *tr = priv->tr;
 
-  g_object_set (G_OBJECT (tr->sink->dtlssrtpenc), "is-client", active, NULL);
+  kms_webrtc_transport_sink_set_dtls_is_client (tr->sink, active);
 
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (tr->src)));
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (tr->sink)));

src/gst-plugins/webrtcendpoint/kmswebrtcconnection.c

@@ -79,7 +79,7 @@ kms_webrtc_connection_get_certificate_pem (KmsWebRtcBaseConnection * base_conn)
 static void
 add_tr (KmsWebRtcTransport * tr, GstBin * bin, gboolean is_client)
 {
-  g_object_set (G_OBJECT (tr->sink->dtlssrtpenc), "is-client", is_client, NULL);
+  kms_webrtc_transport_sink_set_dtls_is_client(tr->sink, is_client);
 
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (tr->src)));
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (tr->sink)));

src/gst-plugins/webrtcendpoint/kmswebrtcrtcpmuxconnection.c

@@ -87,7 +87,7 @@ kms_webrtc_rtcp_mux_connection_add (KmsIRtpConnection * base_rtp_conn,
   KmsWebRtcTransport *tr = priv->tr;
 
   /* srcs */
-  g_object_set (G_OBJECT (tr->sink->dtlssrtpenc), "is-client", active, NULL);
+  kms_webrtc_transport_sink_set_dtls_is_client(tr->sink, active);
 
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (tr->src)));
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (tr->sink)));

src/gst-plugins/webrtcendpoint/kmswebrtcsctpconnection.c

@@ -79,7 +79,7 @@ kms_webrtc_sctp_connection_add (KmsIRtpConnection * base_conn, GstBin * bin,
   KmsWebRtcSctpConnectionPrivate *priv = self->priv;
   KmsWebRtcTransport *tr = priv->tr;
 
-  g_object_set (G_OBJECT (tr->sink->dtlssrtpenc), "is-client", active, NULL);
+  kms_webrtc_transport_sink_set_dtls_is_client(tr->sink, active);
 
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (self->priv->tr->src)));
   gst_bin_add (bin, GST_ELEMENT (g_object_ref (self->priv->tr->sink)));

src/gst-plugins/webrtcendpoint/kmswebrtctransportsink.c

@@ -29,39 +29,83 @@ GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
 #define kms_webrtc_transport_sink_parent_class parent_class
 G_DEFINE_TYPE (KmsWebrtcTransportSink, kms_webrtc_transport_sink, GST_TYPE_BIN);
 
-#define FUNNEL_NAME "funnel"
-#define SRTPENC_NAME "srtp-encoder"
+#define FUNNEL_FACTORY_NAME "funnel"
+#define SRTPENC_FACTORY_NAME "srtpenc"
+#define DTLS_ENCODER_FACTORY_NAME "dtlsenc"
+
+
+
+static GstElement*
+kms_webrtc_transport_sink_get_element_in_dtlssrtpenc (KmsWebrtcTransportSink *self, const gchar *factory_name)
+{
+  GstIterator *iterator;
+  GValue item = G_VALUE_INIT;
+  GstElement *element;
+  GstElementFactory *factory;
+
+  factory = gst_element_factory_find (factory_name);
+
+  if (factory == NULL) {
+    GST_WARNING_OBJECT(self, "Factory %s not installed", factory_name);
+    return NULL;
+  }
+
+  // Until KMS is updated to GStreamer 1.18 and method https://gstreamer.freedesktop.org/documentation/gstreamer/gstbin.html#gst_bin_iterate_all_by_element_factory_name
+  // is available, this will do
+  iterator = gst_bin_iterate_elements (GST_BIN(self->dtlssrtpenc));
+  while (gst_iterator_next (iterator, &item) == GST_ITERATOR_OK) {
+    element = (GstElement *) g_value_get_object (&item);
+    if (factory == gst_element_get_factory (element)) {
+      break;
+    } else {
+      element = NULL;
+    }
+  }
+  gst_iterator_free (iterator);
+  g_object_unref (factory);
+  return element;
+}
 
 static void
 kms_webrtc_transport_sink_init (KmsWebrtcTransportSink * self)
 {
+  GstElement *dtls_encoder;
+
   self->dtlssrtpenc = gst_element_factory_make ("dtlssrtpenc", NULL);
+  dtls_encoder = kms_webrtc_transport_sink_get_element_in_dtlssrtpenc (self, DTLS_ENCODER_FACTORY_NAME);
+  if (dtls_encoder != NULL) {
+    gst_element_set_locked_state (dtls_encoder, TRUE);
+    g_object_unref (dtls_encoder);
+  } else  {
+    GST_WARNING_OBJECT (self, "Cannot get DTLS encoder");
+  }
 }
 
 void
-kms_webrtc_transport_sink_connect_elements (KmsWebrtcTransportSink * self)
+kms_webrtc_transport_sink_connect_elements (KmsWebrtcTransportSink *self)
 {
   GstElement *funnel, *srtpenc;
 
   gst_bin_add_many (GST_BIN (self), self->dtlssrtpenc, self->sink, NULL);
   gst_element_link (self->dtlssrtpenc, self->sink);
 
-  funnel = gst_bin_get_by_name (GST_BIN (self->dtlssrtpenc), FUNNEL_NAME);
+  funnel = kms_webrtc_transport_sink_get_element_in_dtlssrtpenc (self, FUNNEL_FACTORY_NAME);
   if (funnel != NULL) {
     g_object_set (funnel, "forward-sticky-events-mode", 0 /* never */ , NULL);
     g_object_unref (funnel);
   } else {
-    GST_WARNING ("Cannot get funnel with name %s", FUNNEL_NAME);
+    GST_WARNING ("Cannot get funnel with factory %s", FUNNEL_FACTORY_NAME);
   }
 
-  srtpenc = gst_bin_get_by_name (GST_BIN (self->dtlssrtpenc), SRTPENC_NAME);
+  srtpenc = kms_webrtc_transport_sink_get_element_in_dtlssrtpenc (self, SRTPENC_FACTORY_NAME);
   if (srtpenc != NULL) {
     g_object_set (srtpenc, "allow-repeat-tx", TRUE, "replay-window-size",
         RTP_RTX_SIZE, NULL);
     g_object_unref (srtpenc);
   } else {
-    GST_WARNING ("Cannot get srtpenc with name %s", SRTPENC_NAME);
+    GST_WARNING ("Cannot get srtpenc with factory %s", SRTPENC_FACTORY_NAME);
   }
+
 }
 
 void
@@ -77,6 +121,18 @@ kms_webrtc_transport_sink_configure_default (KmsWebrtcTransportSink * self,
   }
 }
 
+void
+kms_webrtc_transport_sink_set_dtls_is_client_default (KmsWebrtcTransportSink * self,
+    gboolean is_client)
+{
+  g_object_set (G_OBJECT (self->dtlssrtpenc), "is-client", is_client, NULL);
+  if (is_client) {
+    GST_DEBUG_OBJECT(self, "Set as DTLS client (handshake initiator)");
+  } else {
+    GST_DEBUG_OBJECT(self, "Set as DTLS server (wait for handshake)");
+  }
+}
+
 void
 kms_webrtc_transport_sink_configure (KmsWebrtcTransportSink * self,
     KmsIceBaseAgent * agent, const char *stream_id, guint component_id)
@@ -87,12 +143,23 @@ kms_webrtc_transport_sink_configure (KmsWebrtcTransportSink * self,
   klass->configure (self, agent, stream_id, component_id);
 }
 
+void
+kms_webrtc_transport_sink_set_dtls_is_client (KmsWebrtcTransportSink * self,
+    gboolean is_client)
+{
+  KmsWebrtcTransportSinkClass *klass =
+      KMS_WEBRTC_TRANSPORT_SINK_CLASS (G_OBJECT_GET_CLASS (self));
+
+  klass->set_dtls_is_client (self, is_client);
+}
+
 static void
 kms_webrtc_transport_sink_class_init (KmsWebrtcTransportSinkClass * klass)
 {
   GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
 
   klass->configure = kms_webrtc_transport_sink_configure_default;
+  klass->set_dtls_is_client = kms_webrtc_transport_sink_set_dtls_is_client_default;
 
   GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, GST_DEFAULT_NAME, 0,
       GST_DEFAULT_NAME);
@@ -104,6 +171,24 @@ kms_webrtc_transport_sink_class_init (KmsWebrtcTransportSinkClass * klass)
       "Miguel París Díaz <mparisdiaz@gmail.com>");
 }
 
+void 
+kms_webrtc_transport_sink_start_dtls (KmsWebrtcTransportSink * self)
+{
+  GstElement *dtls_encoder;
+
+  dtls_encoder = kms_webrtc_transport_sink_get_element_in_dtlssrtpenc (self, DTLS_ENCODER_FACTORY_NAME);
+  if (dtls_encoder != NULL) {
+    gst_element_set_locked_state (dtls_encoder, FALSE);
+    gst_element_sync_state_with_parent (dtls_encoder);
+    GST_DEBUG_OBJECT(self, "Starting DTLS");
+
+    g_object_unref (dtls_encoder);
+  } else  {
+    GST_WARNING_OBJECT ("Cannot get DTLS encoder with factory %s", DTLS_ENCODER_FACTORY_NAME);
+  }
+}
+
+
 KmsWebrtcTransportSink *
 kms_webrtc_transport_sink_new ()
 {

src/gst-plugins/webrtcendpoint/kmswebrtctransportsink.h

@@ -55,6 +55,9 @@ struct _KmsWebrtcTransportSinkClass
                           KmsIceBaseAgent *agent,
                           const char *stream_id,
                           guint component_id);
+
+  void (*set_dtls_is_client) (KmsWebrtcTransportSink * self,
+                          gboolean is_client);
 };
 
 GType kms_webrtc_transport_sink_get_type (void);
@@ -65,5 +68,9 @@ void kms_webrtc_transport_sink_configure (KmsWebrtcTransportSink * self,
                                               KmsIceBaseAgent *agent,
                                               const char *stream_id,
                                               guint component_id);
+void kms_webrtc_transport_sink_set_dtls_is_client (KmsWebrtcTransportSink * self,
+                                              gboolean is_client);
+void kms_webrtc_transport_sink_start_dtls (KmsWebrtcTransportSink * self);
+
 G_END_DECLS
 #endif /* __KMS_WEBRTC_TRANSPORT_SINK_H__ */

src/gst-plugins/webrtcendpoint/kmswebrtctransportsinknice.c

@@ -42,6 +42,25 @@ kms_webrtc_transport_sink_nice_init (KmsWebrtcTransportSinkNice * self)
   kms_webrtc_transport_sink_connect_elements (parent);
 }
 
+static void
+kms_webrtc_transport_sink_nice_component_state_changed (KmsIceBaseAgent * agent,
+    char *stream_id, guint component_id, IceState state,
+    KmsWebrtcTransportSink * self)
+{
+  gboolean is_client;
+
+  GST_LOG_OBJECT (self,
+      "[IceComponentStateChanged] state: %s, stream_id: %s, component_id: %u",
+      kms_ice_base_agent_state_to_string (state), stream_id, component_id);
+
+  g_object_get (G_OBJECT (self->dtlssrtpenc), "is-client",
+          &is_client, NULL);
+
+  if ((state == ICE_STATE_CONNECTED) && is_client) {
+    kms_webrtc_transport_sink_start_dtls (self);
+  }
+}
+
 void
 kms_webrtc_transport_sink_nice_configure (KmsWebrtcTransportSink * self,
     KmsIceBaseAgent * agent, const char *stream_id, guint component_id)
@@ -53,6 +72,26 @@ kms_webrtc_transport_sink_nice_configure (KmsWebrtcTransportSink * self,
       "agent", kms_ice_nice_agent_get_agent (nice_agent),
       "stream", id, "component", component_id,
       "sync", FALSE, "async", FALSE, NULL);
+
+  g_signal_connect (nice_agent, "on-ice-component-state-changed",
+      G_CALLBACK (kms_webrtc_transport_sink_nice_component_state_changed), self);
+}
+
+void
+kms_webrtc_transport_sink_nice_set_dtls_is_client (KmsWebrtcTransportSink * self,
+    gboolean is_client)
+{
+  KmsWebrtcTransportSinkNiceClass *klass =
+      KMS_WEBRTC_TRANSPORT_SINK_NICE_CLASS (G_OBJECT_GET_CLASS (self));
+  KmsWebrtcTransportSinkClass *parent_klass =
+      KMS_WEBRTC_TRANSPORT_SINK_CLASS  (g_type_class_peek_parent(klass));
+
+  parent_klass->set_dtls_is_client (self, is_client);
+
+  if (!is_client) {
+    kms_webrtc_transport_sink_start_dtls (self);
+  }
+
 }
 
 static void
@@ -64,6 +103,7 @@ kms_webrtc_transport_sink_nice_class_init (KmsWebrtcTransportSinkNiceClass *
 
   base_class = KMS_WEBRTC_TRANSPORT_SINK_CLASS (klass);
   base_class->configure = kms_webrtc_transport_sink_nice_configure;
+  base_class->set_dtls_is_client = kms_webrtc_transport_sink_nice_set_dtls_is_client;
 
   GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, GST_DEFAULT_NAME, 0,
       GST_DEFAULT_NAME);

tests/check/element/webrtcendpoint.c

@@ -1744,6 +1744,7 @@ test_data_channels (gboolean bundle)
 
   GST_WARNING ("Finishing test");
 
+  g_usleep (500000);
   gst_element_set_state (pipeline, GST_STATE_NULL);
   gst_bus_remove_signal_watch (bus);
   g_object_unref (bus);