webrtc: allow setting local IP addresses

If a local IP address is specified, ICE gathering can be much faster
in environments where there are multiple IP addreses but only some are
usable (for example, if you are running docker on the machine).

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1223>

ext/webrtc/gstwebrtcbin.c

@@ -325,8 +325,7 @@ gst_webrtc_bin_pad_new (const gchar * name, GstPadDirection direction)
 G_DEFINE_TYPE_WITH_CODE (GstWebRTCBin, gst_webrtc_bin, GST_TYPE_BIN,
     G_ADD_PRIVATE (GstWebRTCBin)
     GST_DEBUG_CATEGORY_INIT (gst_webrtc_bin_debug, "webrtcbin", 0,
-        "webrtcbin element");
-    );
+        "webrtcbin element"););
 
 static GstPad *_connect_input_stream (GstWebRTCBin * webrtc,
     GstWebRTCBinPad * pad);
@@ -349,6 +348,7 @@ enum
   ADD_TURN_SERVER_SIGNAL,
   CREATE_DATA_CHANNEL_SIGNAL,
   ON_DATA_CHANNEL_SIGNAL,
+  ADD_LOCAL_IP_ADDRESS_SIGNAL,
   LAST_SIGNAL,
 };
 
@@ -5025,6 +5025,18 @@ gst_webrtc_bin_add_turn_server (GstWebRTCBin * webrtc, const gchar * uri)
   return gst_webrtc_ice_add_turn_server (webrtc->priv->ice, uri);
 }
 
+static gboolean
+gst_webrtc_bin_add_local_ip_address (GstWebRTCBin * webrtc,
+    const gchar * address)
+{
+  g_return_val_if_fail (GST_IS_WEBRTC_BIN (webrtc), FALSE);
+  g_return_val_if_fail (address != NULL, FALSE);
+
+  GST_DEBUG_OBJECT (webrtc, "Adding local IP address: %s", address);
+
+  return gst_webrtc_ice_add_local_ip_address (webrtc->priv->ice, address);
+}
+
 static gboolean
 copy_sticky_events (GstPad * pad, GstEvent ** event, gpointer user_data)
 {
@@ -6426,6 +6438,20 @@ gst_webrtc_bin_class_init (GstWebRTCBinClass * klass)
       G_CALLBACK (gst_webrtc_bin_add_turn_server), NULL, NULL, NULL,
       G_TYPE_BOOLEAN, 1, G_TYPE_STRING);
 
+  /**
+   * GstWebRTCBin::add-local-ip-address:
+   * @object: the #GstWebRtcBin
+   * @address: The local IP address
+   *
+   * Add a local IP address to use for ICE candidate gathering.  If none
+   * are supplied, they will be discovered automatically
+   */
+  gst_webrtc_bin_signals[ADD_LOCAL_IP_ADDRESS_SIGNAL] =
+      g_signal_new_class_handler ("add-local-ip-address",
+      G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+      G_CALLBACK (gst_webrtc_bin_add_local_ip_address), NULL, NULL,
+      g_cclosure_marshal_generic, G_TYPE_BOOLEAN, 1, G_TYPE_STRING);
+
   /*
    * GstWebRTCBin::create-data-channel:
    * @object: the #GstWebRTCBin

ext/webrtc/gstwebrtcice.c

@@ -82,8 +82,8 @@ struct _GstWebRTCICEPrivate
 #define gst_webrtc_ice_parent_class parent_class
 G_DEFINE_TYPE_WITH_CODE (GstWebRTCICE, gst_webrtc_ice,
     GST_TYPE_OBJECT, G_ADD_PRIVATE (GstWebRTCICE)
-    GST_DEBUG_CATEGORY_INIT (gst_webrtc_ice_debug, "webrtcice", 0, "webrtcice");
-    );
+    GST_DEBUG_CATEGORY_INIT (gst_webrtc_ice_debug, "webrtcice", 0,
+        "webrtcice"););
 
 static gboolean
 _unlock_pc_thread (GMutex * lock)
@@ -670,6 +670,28 @@ done:
   return ret;
 }
 
+gboolean
+gst_webrtc_ice_add_local_ip_address (GstWebRTCICE * ice, const gchar * address)
+{
+  gboolean ret = FALSE;
+  NiceAddress nice_addr;
+
+  nice_address_init (&nice_addr);
+
+  ret = nice_address_set_from_string (&nice_addr, address);
+
+  if (ret) {
+    ret = nice_agent_add_local_address (ice->priv->nice_agent, &nice_addr);
+    if (!ret) {
+      GST_ERROR_OBJECT (ice, "Failed to add local address to NiceAgent");
+    }
+  } else {
+    GST_ERROR_OBJECT (ice, "Failed to initialize NiceAddress [%s]", address);
+  }
+
+  return ret;
+}
+
 gboolean
 gst_webrtc_ice_set_local_credentials (GstWebRTCICE * ice,
     GstWebRTCICEStream * stream, gchar * ufrag, gchar * pwd)

ext/webrtc/gstwebrtcice.h

@@ -81,7 +81,8 @@ gboolean                    gst_webrtc_ice_set_remote_credentials   (GstWebRTCIC
                                                                      gchar * pwd);
 gboolean                    gst_webrtc_ice_add_turn_server          (GstWebRTCICE * ice,
                                                                      const gchar * uri);
-
+gboolean                    gst_webrtc_ice_add_local_ip_address     (GstWebRTCICE * ice,
+                                                                     const gchar * address);
 G_END_DECLS
 
 #endif /* __GST_WEBRTC_ICE_H__ */