webrtc/ice: resolve .local candidates internally

Requires the system's DNS resolver to support mdns resolution.

Fixes interoperablity with recent versions of chrome/firefox that
produce .local address in for local candidates.

Fixes https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/issues/1139
This commit is contained in:
Matthew Waters 2020-08-20 12:58:30 +10:00
parent 8e9f8c7f2c
commit 9011539940

View file

@ -611,6 +611,47 @@ _candidate_type_to_string (NiceCandidateType type)
}
#endif
/* parse the address for possible resolution */
static gboolean
get_candidate_address (const gchar * candidate, gchar ** prefix,
gchar ** address, gchar ** postfix)
{
char **tokens = NULL;
if (!g_str_has_prefix (candidate, "a=candidate:")) {
GST_ERROR ("candidate \"%s\" does not start with \"a=candidate:\"",
candidate);
goto failure;
}
if (!(tokens = g_strsplit (candidate, " ", 6))) {
GST_ERROR ("candidate \"%s\" could not be tokenized", candidate);
goto failure;
}
if (g_strv_length (tokens) < 6) {
GST_ERROR ("candidate \"%s\" tokenization resulted in not enough tokens",
candidate);
goto failure;
}
if (address)
*address = g_strdup (tokens[4]);
tokens[4] = NULL;
if (prefix)
*prefix = g_strjoinv (" ", tokens);
if (postfix)
*postfix = g_strdup (tokens[5]);
g_strfreev (tokens);
return TRUE;
failure:
if (tokens)
g_strfreev (tokens);
return FALSE;
}
/* must start with "a=candidate:" */
void
gst_webrtc_ice_add_candidate (GstWebRTCICE * ice, GstWebRTCICEStream * stream,
@ -627,9 +668,59 @@ gst_webrtc_ice_add_candidate (GstWebRTCICE * ice, GstWebRTCICEStream * stream,
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);
/* might be a .local candidate */
char *prefix = NULL, *address = NULL, *postfix = NULL;
char *new_addr, *new_candidate;
char *new_candv[4] = { NULL, };
if (!get_candidate_address (candidate, &prefix, &address, &postfix)) {
GST_WARNING_OBJECT (ice, "Failed to retrieve address from candidate %s",
candidate);
goto fail;
}
if (!g_str_has_suffix (address, ".local")) {
GST_WARNING_OBJECT (ice, "candidate address \'%s\' does not end "
"with \'.local\'", address);
goto fail;
}
/* FIXME: async */
if (!(new_addr = _resolve_host (ice, address))) {
GST_WARNING_OBJECT (ice, "Failed to resolve %s", address);
goto fail;
}
new_candv[0] = prefix;
new_candv[1] = new_addr;
new_candv[2] = postfix;
new_candv[3] = NULL;
new_candidate = g_strjoinv (" ", new_candv);
GST_DEBUG_OBJECT (ice, "resolved to candidate %s", new_candidate);
cand =
nice_agent_parse_remote_candidate_sdp (ice->priv->nice_agent,
item->nice_stream_id, new_candidate);
g_free (new_candidate);
if (!cand) {
GST_WARNING_OBJECT (ice, "Could not parse candidate \'%s\'",
new_candidate);
goto fail;
}
g_free (prefix);
g_free (new_addr);
g_free (postfix);
if (0) {
fail:
g_free (prefix);
g_free (address);
g_free (postfix);
return;
}
}
candidates = g_slist_append (candidates, cand);