webrtcbin: an element that handles the transport aspects of webrtc connections

SDP's are generated and consumed according to the W3C PeerConnection API
available from https://www.w3.org/TR/webrtc/

The SDP is either created initially from the connected
sink pads/attached transceivers as in the case of generating an offer or
intersected with the connected sink pads/attached transceivers as in
the case for creating an answer.  In both cases, the rtp payloaded streams
sent by the peer are exposed as separate src pads.

The implementation supports trickle ICE, RTCP muxing, reduced size RTCP.

With contributions from:
Nirbheek Chauhan <nirbheek@centricular.com>
Mathieu Duponchelle <mathieu@centricular.com>
Edward Hervey <edward@centricular.com>

https://bugzilla.gnome.org/show_bug.cgi?id=792523

1 files changed, 887 insertions, 0 deletions

diff --git a/ext/webrtc/gstwebrtcice.c b/ext/webrtc/gstwebrtcice.c
new file mode 100644
index 000000000..ce30d3b44
--- /dev/null
+++ b/ext/webrtc/gstwebrtcice.c
@@ -0,0 +1,887 @@
+/* GStreamer
+ * Copyright (C) 2017 Matthew Waters <matthew@centricular.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include "gstwebrtcice.h"
+/* libnice */
+#include <agent.h>
+#include "icestream.h"
+#include "nicetransport.h"
+
+/* XXX:
+ *
+ * - are locally generated remote candidates meant to be readded to libnice?
+ */
+
+#define GST_CAT_DEFAULT gst_webrtc_ice_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+#define gst_webrtc_ice_parent_class parent_class
+G_DEFINE_TYPE_WITH_CODE (GstWebRTCICE, gst_webrtc_ice,
+    GST_TYPE_OBJECT,
+    GST_DEBUG_CATEGORY_INIT (gst_webrtc_ice_debug, "webrtcice", 0, "webrtcice");
+    );
+
+GQuark
+gst_webrtc_ice_error_quark (void)
+{
+  return g_quark_from_static_string ("gst-webrtc-ice-error-quark");
+}
+
+enum
+{
+  SIGNAL_0,
+  ON_ICE_CANDIDATE_SIGNAL,
+  ON_ICE_GATHERING_STATE_CHANGE_SIGNAL,
+  LAST_SIGNAL,
+};
+
+enum
+{
+  PROP_0,
+  PROP_ICE_GATHERING_STATE,
+  PROP_STUN_SERVER,
+  PROP_TURN_SERVER,
+  PROP_CONTROLLER,
+  PROP_AGENT,
+};
+
+static guint gst_webrtc_ice_signals[LAST_SIGNAL] = { 0 };
+
+struct _GstWebRTCICEPrivate
+{
+  NiceAgent *nice_agent;
+
+  GArray *nice_stream_map;
+
+  GThread *thread;
+  GMainContext *main_context;
+  GMainLoop *loop;
+  GMutex lock;
+  GCond cond;
+};
+
+static gboolean
+_unlock_pc_thread (GMutex * lock)
+{
+  g_mutex_unlock (lock);
+  return G_SOURCE_REMOVE;
+}
+
+static gpointer
+_gst_nice_thread (GstWebRTCICE * ice)
+{
+  g_mutex_lock (&ice->priv->lock);
+  ice->priv->main_context = g_main_context_new ();
+  ice->priv->loop = g_main_loop_new (ice->priv->main_context, FALSE);
+
+  g_cond_broadcast (&ice->priv->cond);
+  g_main_context_invoke (ice->priv->main_context,
+      (GSourceFunc) _unlock_pc_thread, &ice->priv->lock);
+
+  g_main_loop_run (ice->priv->loop);
+
+  g_mutex_lock (&ice->priv->lock);
+  g_main_context_unref (ice->priv->main_context);
+  ice->priv->main_context = NULL;
+  g_main_loop_unref (ice->priv->loop);
+  ice->priv->loop = NULL;
+  g_cond_broadcast (&ice->priv->cond);
+  g_mutex_unlock (&ice->priv->lock);
+
+  return NULL;
+}
+
+static void
+_start_thread (GstWebRTCICE * ice)
+{
+  g_mutex_lock (&ice->priv->lock);
+  ice->priv->thread = g_thread_new ("gst-nice-ops",
+      (GThreadFunc) _gst_nice_thread, ice);
+
+  while (!ice->priv->loop)
+    g_cond_wait (&ice->priv->cond, &ice->priv->lock);
+  g_mutex_unlock (&ice->priv->lock);
+}
+
+static void
+_stop_thread (GstWebRTCICE * ice)
+{
+  g_mutex_lock (&ice->priv->lock);
+  g_main_loop_quit (ice->priv->loop);
+  while (ice->priv->loop)
+    g_cond_wait (&ice->priv->cond, &ice->priv->lock);
+  g_mutex_unlock (&ice->priv->lock);
+
+  g_thread_unref (ice->priv->thread);
+}
+
+#if 0
+static NiceComponentType
+_webrtc_component_to_nice (GstWebRTCICEComponent comp)
+{
+  switch (comp) {
+    case GST_WEBRTC_ICE_COMPONENT_RTP:
+      return NICE_COMPONENT_TYPE_RTP;
+    case GST_WEBRTC_ICE_COMPONENT_RTCP:
+      return NICE_COMPONENT_TYPE_RTCP;
+    default:
+      g_assert_not_reached ();
+      return 0;
+  }
+}
+
+static GstWebRTCICEComponent
+_nice_component_to_webrtc (NiceComponentType comp)
+{
+  switch (comp) {
+    case NICE_COMPONENT_TYPE_RTP:
+      return GST_WEBRTC_ICE_COMPONENT_RTP;
+    case NICE_COMPONENT_TYPE_RTCP:
+      return GST_WEBRTC_ICE_COMPONENT_RTCP;
+    default:
+      g_assert_not_reached ();
+      return 0;
+  }
+}
+#endif
+struct NiceStreamItem
+{
+  guint session_id;
+  guint nice_stream_id;
+  GstWebRTCICEStream *stream;
+};
+
+/* TRUE to continue, FALSE to stop */
+typedef gboolean (*NiceStreamItemForeachFunc) (struct NiceStreamItem * item,
+    gpointer user_data);
+
+static void
+_nice_stream_item_foreach (GstWebRTCICE * ice, NiceStreamItemForeachFunc func,
+    gpointer data)
+{
+  int i, len;
+
+  len = ice->priv->nice_stream_map->len;
+  for (i = 0; i < len; i++) {
+    struct NiceStreamItem *item =
+        &g_array_index (ice->priv->nice_stream_map, struct NiceStreamItem,
+        i);
+
+    if (!func (item, data))
+      break;
+  }
+}
+
+/* TRUE for match, FALSE otherwise */
+typedef gboolean (*NiceStreamItemFindFunc) (struct NiceStreamItem * item,
+    gpointer user_data);
+
+struct nice_find
+{
+  NiceStreamItemFindFunc func;
+  gpointer data;
+  struct NiceStreamItem *ret;
+};
+
+static gboolean
+_find_nice_item (struct NiceStreamItem *item, gpointer user_data)
+{
+  struct nice_find *f = user_data;
+  if (f->func (item, f->data)) {
+    f->ret = item;
+    return FALSE;
+  }
+  return TRUE;
+}
+
+static struct NiceStreamItem *
+_nice_stream_item_find (GstWebRTCICE * ice, NiceStreamItemFindFunc func,
+    gpointer data)
+{
+  struct nice_find f;
+
+  f.func = func;
+  f.data = data;
+  f.ret = NULL;
+
+  _nice_stream_item_foreach (ice, _find_nice_item, &f);
+
+  return f.ret;
+}
+
+#define NICE_MATCH_INIT { -1, -1, NULL }
+
+static gboolean
+_match (struct NiceStreamItem *item, struct NiceStreamItem *m)
+{
+  if (m->session_id != -1 && m->session_id != item->session_id)
+    return FALSE;
+  if (m->nice_stream_id != -1 && m->nice_stream_id != item->nice_stream_id)
+    return FALSE;
+  if (m->stream != NULL && m->stream != item->stream)
+    return FALSE;
+
+  return TRUE;
+}
+
+static struct NiceStreamItem *
+_find_item (GstWebRTCICE * ice, guint session_id, guint nice_stream_id,
+    GstWebRTCICEStream * stream)
+{
+  struct NiceStreamItem m = NICE_MATCH_INIT;
+
+  m.session_id = session_id;
+  m.nice_stream_id = nice_stream_id;
+  m.stream = stream;
+
+  return _nice_stream_item_find (ice, (NiceStreamItemFindFunc) _match, &m);
+}
+
+static struct NiceStreamItem *
+_create_nice_stream_item (GstWebRTCICE * ice, guint session_id)
+{
+  struct NiceStreamItem item;
+
+  item.session_id = session_id;
+  item.nice_stream_id = nice_agent_add_stream (ice->priv->nice_agent, 2);
+  item.stream = gst_webrtc_ice_stream_new (ice, item.nice_stream_id);
+  g_array_append_val (ice->priv->nice_stream_map, item);
+
+  return _find_item (ice, item.session_id, item.nice_stream_id, item.stream);
+}
+
+static void
+_parse_userinfo (const gchar * userinfo, gchar ** user, gchar ** pass)
+{
+  const gchar *colon;
+
+  if (!userinfo) {
+    *user = NULL;
+    *pass = NULL;
+    return;
+  }
+
+  colon = g_strstr_len (userinfo, -1, ":");
+  if (!colon) {
+    *user = g_strdup (userinfo);
+    *pass = NULL;
+    return;
+  }
+
+  *user = g_strndup (userinfo, colon - userinfo);
+  *pass = g_strdup (&colon[1]);
+}
+
+GstWebRTCICEStream *
+gst_webrtc_ice_add_stream (GstWebRTCICE * ice, guint session_id)
+{
+  struct NiceStreamItem m = NICE_MATCH_INIT;
+  struct NiceStreamItem *item;
+
+  m.session_id = session_id;
+  item = _nice_stream_item_find (ice, (NiceStreamItemFindFunc) _match, &m);
+  if (item) {
+    GST_ERROR_OBJECT (ice, "stream already added with session_id=%u",
+        session_id);
+    return 0;
+  }
+
+  item = _create_nice_stream_item (ice, session_id);
+
+  if (ice->turn_server) {
+    gboolean ret;
+    gchar *user, *pass;
+    const gchar *userinfo, *transport, *scheme;
+    NiceRelayType relays[4] = { 0, };
+    int i, relay_n = 0;
+
+    scheme = gst_uri_get_scheme (ice->turn_server);
+    transport = gst_uri_get_query_value (ice->turn_server, "transport");
+    userinfo = gst_uri_get_userinfo (ice->turn_server);
+    _parse_userinfo (userinfo, &user, &pass);
+
+    if (g_strcmp0 (scheme, "turns") == 0) {
+      relays[relay_n++] = NICE_RELAY_TYPE_TURN_TLS;
+    } else if (g_strcmp0 (scheme, "turn") == 0) {
+      if (!transport || g_strcmp0 (transport, "udp") == 0)
+        relays[relay_n++] = NICE_RELAY_TYPE_TURN_UDP;
+      if (!transport || g_strcmp0 (transport, "tcp") == 0)
+        relays[relay_n++] = NICE_RELAY_TYPE_TURN_TCP;
+    }
+    g_assert (relay_n < G_N_ELEMENTS (relays));
+
+    for (i = 0; i < relay_n; i++) {
+      ret = nice_agent_set_relay_info (ice->priv->nice_agent,
+          item->nice_stream_id, NICE_COMPONENT_TYPE_RTP,
+          gst_uri_get_host (ice->turn_server),
+          gst_uri_get_port (ice->turn_server), user, pass, relays[i]);
+      if (!ret) {
+        gchar *uri = gst_uri_to_string (ice->turn_server);
+        GST_ERROR_OBJECT (ice, "Failed to set TURN server '%s'", uri);
+        g_free (uri);
+        break;
+      }
+      ret = nice_agent_set_relay_info (ice->priv->nice_agent,
+          item->nice_stream_id, NICE_COMPONENT_TYPE_RTCP,
+          gst_uri_get_host (ice->turn_server),
+          gst_uri_get_port (ice->turn_server), user, pass, relays[i]);
+      if (!ret) {
+        gchar *uri = gst_uri_to_string (ice->turn_server);
+        GST_ERROR_OBJECT (ice, "Failed to set TURN server '%s'", uri);
+        g_free (uri);
+        break;
+      }
+    }
+    g_free (user);
+    g_free (pass);
+  }
+
+  return item->stream;
+}
+
+static void
+_on_new_candidate (NiceAgent * agent, NiceCandidate * candidate,
+    GstWebRTCICE * ice)
+{
+  struct NiceStreamItem *item;
+  gchar *attr;
+
+  item = _find_item (ice, -1, candidate->stream_id, NULL);
+  if (!item) {
+    GST_WARNING_OBJECT (ice, "received signal for non-existent stream %u",
+        candidate->stream_id);
+    return;
+  }
+
+  if (!candidate->username || !candidate->password) {
+    gboolean got_credentials;
+    gchar *ufrag, *password;
+
+    got_credentials = nice_agent_get_local_credentials (ice->priv->nice_agent,
+        candidate->stream_id, &ufrag, &password);
+    g_warn_if_fail (got_credentials);
+
+    if (!candidate->username)
+      candidate->username = ufrag;
+    else
+      g_free (ufrag);
+
+    if (!candidate->password)
+      candidate->password = password;
+    else
+      g_free (password);
+  }
+
+  attr = nice_agent_generate_local_candidate_sdp (agent, candidate);
+  g_signal_emit (ice, gst_webrtc_ice_signals[ON_ICE_CANDIDATE_SIGNAL],
+      0, item->session_id, attr);
+  g_free (attr);
+}
+
+GstWebRTCICETransport *
+gst_webrtc_ice_find_transport (GstWebRTCICE * ice, GstWebRTCICEStream * stream,
+    GstWebRTCICEComponent component)
+{
+  struct NiceStreamItem *item;
+
+  item = _find_item (ice, -1, -1, stream);
+  g_return_val_if_fail (item != NULL, NULL);
+
+  return gst_webrtc_ice_stream_find_transport (item->stream, component);
+}
+
+#if 0
+/* TODO don't rely on libnice to (de)serialize candidates */
+static NiceCandidateType
+_candidate_type_from_string (const gchar * s)
+{
+  if (g_strcmp0 (s, "host") == 0) {
+    return NICE_CANDIDATE_TYPE_HOST;
+  } else if (g_strcmp0 (s, "srflx") == 0) {
+    return NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE;
+  } else if (g_strcmp0 (s, "prflx") == 0) {     /* FIXME: is the right string? */
+    return NICE_CANDIDATE_TYPE_PEER_REFLEXIVE;
+  } else if (g_strcmp0 (s, "relay") == 0) {
+    return NICE_CANDIDATE_TYPE_RELAY;
+  } else {
+    g_assert_not_reached ();
+    return 0;
+  }
+}
+
+static const gchar *
+_candidate_type_to_string (NiceCandidateType type)
+{
+  switch (type) {
+    case NICE_CANDIDATE_TYPE_HOST:
+      return "host";
+    case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE:
+      return "srflx";
+    case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:
+      return "prflx";
+    case NICE_CANDIDATE_TYPE_RELAY:
+      return "relay";
+    default:
+      g_assert_not_reached ();
+      return NULL;
+  }
+}
+
+static NiceCandidateTransport
+_candidate_transport_from_string (const gchar * s)
+{
+  if (g_strcmp0 (s, "UDP") == 0) {
+    return NICE_CANDIDATE_TRANSPORT_UDP;
+  } else if (g_strcmp0 (s, "TCP tcptype") == 0) {
+    return NICE_CANDIDATE_TRANSPORT_TCP_ACTIVE;
+  } else if (g_strcmp0 (s, "tcp-passive") == 0) {       /* FIXME: is the right string? */
+    return NICE_CANDIDATE_TRANSPORT_TCP_PASSIVE;
+  } else if (g_strcmp0 (s, "tcp-so") == 0) {
+    return NICE_CANDIDATE_TRANSPORT_TCP_SO;
+  } else {
+    g_assert_not_reached ();
+    return 0;
+  }
+}
+
+static const gchar *
+_candidate_type_to_string (NiceCandidateType type)
+{
+  switch (type) {
+    case NICE_CANDIDATE_TYPE_HOST:
+      return "host";
+    case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE:
+      return "srflx";
+    case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:
+      return "prflx";
+    case NICE_CANDIDATE_TYPE_RELAY:
+      return "relay";
+    default:
+      g_assert_not_reached ();
+      return NULL;
+  }
+}
+#endif
+
+/* must start with "a=candidate:" */
+void
+gst_webrtc_ice_add_candidate (GstWebRTCICE * ice, GstWebRTCICEStream * stream,
+    const gchar * candidate)
+{
+  struct NiceStreamItem *item;
+  NiceCandidate *cand;
+  GSList *candidates = NULL;
+
+  item = _find_item (ice, -1, -1, stream);
+  g_return_if_fail (item != NULL);
+
+  cand =
+      nice_agent_parse_remote_candidate_sdp (ice->priv->nice_agent,
+      item->nice_stream_id, candidate);
+  if (!cand) {
+    GST_WARNING_OBJECT (ice, "Could not parse candidate \'%s\'", candidate);
+    return;
+  }
+
+  candidates = g_slist_append (candidates, cand);
+
+  nice_agent_set_remote_candidates (ice->priv->nice_agent, item->nice_stream_id,
+      cand->component_id, candidates);
+
+  g_slist_free (candidates);
+  nice_candidate_free (cand);
+}
+
+gboolean
+gst_webrtc_ice_set_remote_credentials (GstWebRTCICE * ice,
+    GstWebRTCICEStream * stream, gchar * ufrag, gchar * pwd)
+{
+  struct NiceStreamItem *item;
+
+  g_return_val_if_fail (ufrag != NULL, FALSE);
+  g_return_val_if_fail (pwd != NULL, FALSE);
+  item = _find_item (ice, -1, -1, stream);
+  g_return_val_if_fail (item != NULL, FALSE);
+
+  GST_DEBUG_OBJECT (ice, "Setting remote ICE credentials on "
+      "ICE stream %u ufrag:%s pwd:%s", item->nice_stream_id, ufrag, pwd);
+
+  nice_agent_set_remote_credentials (ice->priv->nice_agent,
+      item->nice_stream_id, ufrag, pwd);
+
+  return TRUE;
+}
+
+gboolean
+gst_webrtc_ice_set_local_credentials (GstWebRTCICE * ice,
+    GstWebRTCICEStream * stream, gchar * ufrag, gchar * pwd)
+{
+  struct NiceStreamItem *item;
+
+  g_return_val_if_fail (ufrag != NULL, FALSE);
+  g_return_val_if_fail (pwd != NULL, FALSE);
+  item = _find_item (ice, -1, -1, stream);
+  g_return_val_if_fail (item != NULL, FALSE);
+
+  GST_DEBUG_OBJECT (ice, "Setting local ICE credentials on "
+      "ICE stream %u ufrag:%s pwd:%s", item->nice_stream_id, ufrag, pwd);
+
+  nice_agent_set_local_credentials (ice->priv->nice_agent, item->nice_stream_id,
+      ufrag, pwd);
+
+  return TRUE;
+}
+
+gboolean
+gst_webrtc_ice_gather_candidates (GstWebRTCICE * ice,
+    GstWebRTCICEStream * stream)
+{
+  struct NiceStreamItem *item;
+
+  item = _find_item (ice, -1, -1, stream);
+  g_return_val_if_fail (item != NULL, FALSE);
+
+  GST_DEBUG_OBJECT (ice, "gather candidates for stream %u",
+      item->nice_stream_id);
+
+  return gst_webrtc_ice_stream_gather_candidates (stream);
+}
+
+static void
+_clear_ice_stream (struct NiceStreamItem *item)
+{
+  if (!item)
+    return;
+
+  if (item->stream) {
+    g_signal_handlers_disconnect_by_data (item->stream->ice->priv->nice_agent,
+        item->stream);
+    gst_object_unref (item->stream);
+  }
+}
+
+static gchar *
+_resolve_host (const gchar * host)
+{
+  GResolver *resolver = g_resolver_get_default ();
+  GError *error = NULL;
+  GInetAddress *addr;
+  GList *addresses;
+
+  if (!(addresses = g_resolver_lookup_by_name (resolver, host, NULL, &error))) {
+    GST_ERROR ("%s", error->message);
+    g_clear_error (&error);
+    return NULL;
+  }
+
+  /* XXX: only the first address is used */
+  addr = addresses->data;
+
+  return g_inet_address_to_string (addr);
+}
+
+static void
+_set_turn_server (GstWebRTCICE * ice, const gchar * s)
+{
+  GstUri *uri = gst_uri_from_string (s);
+  const gchar *userinfo, *host, *scheme;
+  GList *keys = NULL, *l;
+  gchar *ip = NULL, *user = NULL, *pass = NULL;
+  gboolean turn_tls = FALSE;
+  guint port;
+
+  GST_DEBUG_OBJECT (ice, "setting turn server, %s", s);
+
+  if (!uri) {
+    GST_ERROR_OBJECT (ice, "Could not parse turn server '%s'", s);
+    return;
+  }
+
+  scheme = gst_uri_get_scheme (uri);
+  if (g_strcmp0 (scheme, "turn") == 0) {
+  } else if (g_strcmp0 (scheme, "turns") == 0) {
+    turn_tls = TRUE;
+  } else {
+    GST_ERROR_OBJECT (ice, "unknown scheme '%s'", scheme);
+    goto out;
+  }
+
+  keys = gst_uri_get_query_keys (uri);
+  for (l = keys; l; l = l->next) {
+    gchar *key = l->data;
+
+    if (g_strcmp0 (key, "transport") == 0) {
+      const gchar *transport = gst_uri_get_query_value (uri, "transport");
+      if (!transport) {
+      } else if (g_strcmp0 (transport, "udp") == 0) {
+      } else if (g_strcmp0 (transport, "tcp") == 0) {
+      } else {
+        GST_ERROR_OBJECT (ice, "unknown transport value, '%s'", transport);
+        goto out;
+      }
+    } else {
+      GST_ERROR_OBJECT (ice, "unknown query key, '%s'", key);
+      goto out;
+    }
+  }
+
+  /* TODO: Implement error checking similar to the stun server below */
+  userinfo = gst_uri_get_userinfo (uri);
+  _parse_userinfo (userinfo, &user, &pass);
+  if (!user) {
+    GST_ERROR_OBJECT (ice, "No username specified in '%s'", s);
+    goto out;
+  }
+  if (!pass) {
+    GST_ERROR_OBJECT (ice, "No password specified in '%s'", s);
+    goto out;
+  }
+
+  host = gst_uri_get_host (uri);
+  if (!host) {
+    GST_ERROR_OBJECT (ice, "Turn server has no host");
+    goto out;
+  }
+  ip = _resolve_host (host);
+  if (!ip) {
+    GST_ERROR_OBJECT (ice, "Failed to resolve turn server '%s'", host);
+    goto out;
+  }
+  port = gst_uri_get_port (uri);
+
+  if (port == GST_URI_NO_PORT) {
+    if (turn_tls) {
+      gst_uri_set_port (uri, 5349);
+    } else {
+      gst_uri_set_port (uri, 3478);
+    }
+  }
+  /* Set the resolved IP as the host since that's what libnice wants */
+  gst_uri_set_host (uri, ip);
+
+  if (ice->turn_server)
+    gst_uri_unref (ice->turn_server);
+  ice->turn_server = uri;
+
+out:
+  g_list_free (keys);
+  g_free (ip);
+  g_free (user);
+  g_free (pass);
+}
+
+static void
+gst_webrtc_ice_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstWebRTCICE *ice = GST_WEBRTC_ICE (object);
+
+  switch (prop_id) {
+    case PROP_STUN_SERVER:{
+      const gchar *s = g_value_get_string (value);
+      GstUri *uri = gst_uri_from_string (s);
+      const gchar *msg = "must be of the form stun://<host>:<port>";
+      const gchar *host;
+      gchar *ip;
+      guint port;
+
+      GST_DEBUG_OBJECT (ice, "setting stun server, %s", s);
+
+      if (!uri) {
+        GST_ERROR_OBJECT (ice, "Couldn't parse stun server '%s', %s", s, msg);
+        return;
+      }
+
+      host = gst_uri_get_host (uri);
+      if (!host) {
+        GST_ERROR_OBJECT (ice, "Stun server '%s' has no host, %s", s, msg);
+        return;
+      }
+      port = gst_uri_get_port (uri);
+      if (port == GST_URI_NO_PORT) {
+        GST_INFO_OBJECT (ice, "Stun server '%s' has no port, assuming 3478", s);
+        port = 3478;
+        gst_uri_set_port (uri, port);
+      }
+
+      ip = _resolve_host (host);
+      if (!ip) {
+        GST_ERROR_OBJECT (ice, "Failed to resolve stun server '%s'", host);
+        return;
+      }
+
+      if (ice->stun_server)
+        gst_uri_unref (ice->stun_server);
+      ice->stun_server = uri;
+
+      g_object_set (ice->priv->nice_agent, "stun-server", ip,
+          "stun-server-port", port, NULL);
+
+      g_free (ip);
+      break;
+    }
+    case PROP_TURN_SERVER:{
+      _set_turn_server (ice, g_value_get_string (value));
+      break;
+    }
+    case PROP_CONTROLLER:
+      g_object_set_property (G_OBJECT (ice->priv->nice_agent),
+          "controlling-mode", value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_webrtc_ice_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstWebRTCICE *ice = GST_WEBRTC_ICE (object);
+
+  switch (prop_id) {
+    case PROP_STUN_SERVER:
+      if (ice->stun_server)
+        g_value_take_string (value, gst_uri_to_string (ice->stun_server));
+      else
+        g_value_take_string (value, NULL);
+      break;
+    case PROP_TURN_SERVER:
+      if (ice->turn_server)
+        g_value_take_string (value, gst_uri_to_string (ice->turn_server));
+      else
+        g_value_take_string (value, NULL);
+      break;
+    case PROP_CONTROLLER:
+      g_object_get_property (G_OBJECT (ice->priv->nice_agent),
+          "controlling-mode", value);
+      break;
+    case PROP_AGENT:
+      g_value_set_object (value, ice->priv->nice_agent);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_webrtc_ice_finalize (GObject * object)
+{
+  GstWebRTCICE *ice = GST_WEBRTC_ICE (object);
+
+  g_signal_handlers_disconnect_by_data (ice->priv->nice_agent, ice);
+
+  _stop_thread (ice);
+
+  if (ice->turn_server)
+    gst_uri_unref (ice->turn_server);
+  if (ice->stun_server)
+    gst_uri_unref (ice->stun_server);
+
+  g_mutex_clear (&ice->priv->lock);
+  g_cond_clear (&ice->priv->cond);
+
+  g_array_free (ice->priv->nice_stream_map, TRUE);
+
+  g_object_unref (ice->priv->nice_agent);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gst_webrtc_ice_class_init (GstWebRTCICEClass * klass)
+{
+  GObjectClass *gobject_class = (GObjectClass *) klass;
+
+  g_type_class_add_private (klass, sizeof (GstWebRTCICEPrivate));
+
+  gobject_class->get_property = gst_webrtc_ice_get_property;
+  gobject_class->set_property = gst_webrtc_ice_set_property;
+  gobject_class->finalize = gst_webrtc_ice_finalize;
+
+  g_object_class_install_property (gobject_class,
+      PROP_STUN_SERVER,
+      g_param_spec_string ("stun-server", "STUN Server",
+          "The STUN server of the form stun://hostname:port",
+          NULL, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class,
+      PROP_TURN_SERVER,
+      g_param_spec_string ("turn-server", "TURN Server",
+          "The TURN server of the form turn(s)://username:password@host:port",
+          NULL, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class,
+      PROP_CONTROLLER,
+      g_param_spec_boolean ("controller", "ICE controller",
+          "Whether the ICE agent is the controller or controlled. "
+          "In WebRTC, the initial offerrer is the ICE controller.", FALSE,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class,
+      PROP_AGENT,
+      g_param_spec_object ("agent", "ICE agent",
+          "ICE agent in use by this object", NICE_TYPE_AGENT,
+          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
+  /**
+   * GstWebRTCICE::on-ice-candidate:
+   * @object: the #GstWebRtcBin
+   * @candidate: the ICE candidate
+   */
+  gst_webrtc_ice_signals[ON_ICE_CANDIDATE_SIGNAL] =
+      g_signal_new ("on-ice-candidate", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, 0, NULL, NULL, g_cclosure_marshal_generic,
+      G_TYPE_NONE, 2, G_TYPE_UINT, G_TYPE_STRING);
+}
+
+static void
+gst_webrtc_ice_init (GstWebRTCICE * ice)
+{
+  ice->priv =
+      G_TYPE_INSTANCE_GET_PRIVATE ((ice), GST_TYPE_WEBRTC_ICE,
+      GstWebRTCICEPrivate);
+
+  g_mutex_init (&ice->priv->lock);
+  g_cond_init (&ice->priv->cond);
+
+  _start_thread (ice);
+
+  ice->priv->nice_agent = nice_agent_new (ice->priv->main_context,
+      NICE_COMPATIBILITY_RFC5245);
+  g_signal_connect (ice->priv->nice_agent, "new-candidate-full",
+      G_CALLBACK (_on_new_candidate), ice);
+
+  ice->priv->nice_stream_map =
+      g_array_new (FALSE, TRUE, sizeof (struct NiceStreamItem));
+  g_array_set_clear_func (ice->priv->nice_stream_map,
+      (GDestroyNotify) _clear_ice_stream);
+}
+
+GstWebRTCICE *
+gst_webrtc_ice_new (void)
+{
+  return g_object_new (GST_TYPE_WEBRTC_ICE, NULL);
+}