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webrtcbin: Prevent ICE gathering state reaching complete early

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The ICE gathering state can transition to complete prematurely if the
underlying ICE components complete their gathering while the initial
ICE gathering state task is queued and still pending.

In that situation, the ice gathering state task will report complete
while there are still ICE candidates queued for emission.

Prevent that by storing ICE candidates in an array and checking if
there are any pending before reporting a completed ICE gathering
state.
This commit is contained in:
Jan Schmidt 2020-03-10 05:18:40 +11:00
parent 9410ef56b8
commit 8274fcd311
2 changed files with 89 additions and 28 deletions
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116
ext/webrtc/gstwebrtcbin.c
View file

@ -1156,6 +1156,19 @@ _update_ice_gathering_state_task (GstWebRTCBin * webrtc, gpointer data)
new_state = _collate_ice_gathering_states (webrtc);
/* If the new state is complete, before we update the public state,
* check if anyone published more ICE candidates while we were collating
* and stop if so, because it means there's a new later
* ice_gathering_state_task queued */
if (new_state == GST_WEBRTC_ICE_GATHERING_STATE_COMPLETE) {
ICE_LOCK (webrtc);
if (webrtc->priv->pending_local_ice_candidates->len != 0) {
/* ICE candidates queued for emissiong -> we're gathering, not complete */
new_state = GST_WEBRTC_ICE_GATHERING_STATE_GATHERING;
}
ICE_UNLOCK (webrtc);
}
if (new_state != webrtc->ice_gathering_state) {
gchar *old_s, *new_s;
@ -4646,50 +4659,88 @@ gst_webrtc_bin_add_ice_candidate (GstWebRTCBin * webrtc, guint mline,
}
static void
_on_ice_candidate_task (GstWebRTCBin * webrtc, IceCandidateItem * item)
_on_local_ice_candidate_task (GstWebRTCBin * webrtc)
{
const gchar *cand = item->candidate;
gsize i;
GArray *items;
if (!g_ascii_strncasecmp (cand, "a=candidate:", 12)) {
/* stripping away "a=" */
cand += 2;
ICE_LOCK (webrtc);
if (webrtc->priv->pending_local_ice_candidates->len == 0) {
ICE_UNLOCK (webrtc);
GST_LOG_OBJECT (webrtc, "No ICE candidates to process right now");
return; /* Nothing to process */
}
/* Take the array so we can process it all and free it later
* without holding the lock
* FIXME: When we depend on GLib 2.64, we can use g_array_steal()
* here */
items = webrtc->priv->pending_local_ice_candidates;
/* Replace with a new array */
webrtc->priv->pending_local_ice_candidates =
g_array_new (FALSE, TRUE, sizeof (IceCandidateItem *));
g_array_set_clear_func (webrtc->priv->pending_local_ice_candidates,
(GDestroyNotify) _clear_ice_candidate_item);
ICE_UNLOCK (webrtc);
GST_TRACE_OBJECT (webrtc, "produced ICE candidate for mline:%u and %s",
item->mlineindex, cand);
for (i = 0; i < items->len; i++) {
IceCandidateItem *item = g_array_index (items, IceCandidateItem *, i);
const gchar *cand = item->candidate;
/* First, merge this ice candidate into the appropriate mline
* in the local-description SDP.
* Second, emit the on-ice-candidate signal for the app.
*
* FIXME: This ICE candidate should be stored somewhere with
* the associated mid and also merged back into any subsequent
* local descriptions on renegotiation */
if (webrtc->current_local_description)
_add_ice_candidate_to_sdp (webrtc, webrtc->current_local_description->sdp,
item->mlineindex, cand);
if (webrtc->pending_local_description)
_add_ice_candidate_to_sdp (webrtc, webrtc->pending_local_description->sdp,
if (!g_ascii_strncasecmp (cand, "a=candidate:", 12)) {
/* stripping away "a=" */
cand += 2;
}
GST_TRACE_OBJECT (webrtc, "produced ICE candidate for mline:%u and %s",
item->mlineindex, cand);
PC_UNLOCK (webrtc);
g_signal_emit (webrtc, gst_webrtc_bin_signals[ON_ICE_CANDIDATE_SIGNAL],
0, item->mlineindex, cand);
PC_LOCK (webrtc);
/* First, merge this ice candidate into the appropriate mline
* in the local-description SDP.
* Second, emit the on-ice-candidate signal for the app.
*
* FIXME: This ICE candidate should be stored somewhere with
* the associated mid and also merged back into any subsequent
* local descriptions on renegotiation */
if (webrtc->current_local_description)
_add_ice_candidate_to_sdp (webrtc, webrtc->current_local_description->sdp,
item->mlineindex, cand);
if (webrtc->pending_local_description)
_add_ice_candidate_to_sdp (webrtc, webrtc->pending_local_description->sdp,
item->mlineindex, cand);
PC_UNLOCK (webrtc);
g_signal_emit (webrtc, gst_webrtc_bin_signals[ON_ICE_CANDIDATE_SIGNAL],
0, item->mlineindex, cand);
PC_LOCK (webrtc);
}
g_array_free (items, TRUE);
}
static void
_on_ice_candidate (GstWebRTCICE * ice, guint session_id,
_on_local_ice_candidate_cb (GstWebRTCICE * ice, guint session_id,
gchar * candidate, GstWebRTCBin * webrtc)
{
IceCandidateItem *item = g_new0 (IceCandidateItem, 1);
gboolean queue_task = FALSE;
item->mlineindex = session_id;
item->candidate = g_strdup (candidate);
gst_webrtc_bin_enqueue_task (webrtc,
(GstWebRTCBinFunc) _on_ice_candidate_task, item,
(GDestroyNotify) _free_ice_candidate_item);
ICE_LOCK (webrtc);
g_array_append_val (webrtc->priv->pending_local_ice_candidates, item);
/* Let the first pending candidate queue a task each time, which will
* handle any that arrive between now and when the task runs */
if (webrtc->priv->pending_local_ice_candidates->len == 1)
queue_task = TRUE;
ICE_UNLOCK (webrtc);
if (queue_task) {
GST_TRACE_OBJECT (webrtc, "Queueing on_ice_candidate_task");
gst_webrtc_bin_enqueue_task (webrtc,
(GstWebRTCBinFunc) _on_local_ice_candidate_task, NULL, NULL);
}
}
/* https://www.w3.org/TR/webrtc/#dfn-stats-selection-algorithm */
@ -5779,6 +5830,10 @@ gst_webrtc_bin_finalize (GObject * object)
g_array_free (webrtc->priv->pending_remote_ice_candidates, TRUE);
webrtc->priv->pending_remote_ice_candidates = NULL;
if (webrtc->priv->pending_local_ice_candidates)
g_array_free (webrtc->priv->pending_local_ice_candidates, TRUE);
webrtc->priv->pending_local_ice_candidates = NULL;
if (webrtc->priv->session_mid_map)
g_array_free (webrtc->priv->session_mid_map, TRUE);
webrtc->priv->session_mid_map = NULL;
@ -6289,7 +6344,7 @@ gst_webrtc_bin_init (GstWebRTCBin * webrtc)
webrtc->priv->ice = gst_webrtc_ice_new ();
g_signal_connect (webrtc->priv->ice, "on-ice-candidate",
G_CALLBACK (_on_ice_candidate), webrtc);
G_CALLBACK (_on_local_ice_candidate_cb), webrtc);
webrtc->priv->ice_stream_map =
g_array_new (FALSE, TRUE, sizeof (IceStreamItem));
webrtc->priv->pending_remote_ice_candidates =
@ -6297,6 +6352,11 @@ gst_webrtc_bin_init (GstWebRTCBin * webrtc)
g_array_set_clear_func (webrtc->priv->pending_remote_ice_candidates,
(GDestroyNotify) _clear_ice_candidate_item);
webrtc->priv->pending_local_ice_candidates =
g_array_new (FALSE, TRUE, sizeof (IceCandidateItem *));
g_array_set_clear_func (webrtc->priv->pending_local_ice_candidates,
(GDestroyNotify) _clear_ice_candidate_item);
/* we start off closed until we move to READY */
webrtc->priv->is_closed = TRUE;
}

1
ext/webrtc/gstwebrtcbin.h
View file

@ -111,6 +111,7 @@ struct _GstWebRTCBinPrivate
GArray *ice_stream_map;
GMutex ice_lock;
GArray *pending_remote_ice_candidates;
GArray *pending_local_ice_candidates;
/* peerconnection variables */
gboolean is_closed;