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bridging: Add better support for adding/removing streams.

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This change adds support to bridge_softmix to allow the addition
and removal of additional video source streams. When such a change
occurs each participant is renegotiated as needed to reflect the
update. If another video source is added then each participant
gets another source. If a video source is removed then it is
removed from each participant. This functionality allows you to
have both your webcam and screenshare providing video if you
desire, or even more streams. Mapping has been changed to use
the topology index on the source channel as a unique identifier
for outgoing participant streams, this will never change and
provides an easy way to establish the mapping.

The bridge_simple and bridge_native_rtp modules have also been
updated to renegotiate when the stream topology of a party changes
allowing the same behavior to occur as added to bridge_softmix.
If a screen share is added then the opposite party is renegotiated.
If that screen share is removed then the opposite party is
renegotiated again.

Some additional fixes are also included in here. Stream state is
now conveyed in SDP so sendonly/recvonly/inactive streams can
be requested. Removed streams now also remove previous state
from themselves so consumers don't get confused.

ASTERISK-28733

Change-Id: I93f41fb41b85646bef71408111c17ccea30cb0c5
This commit is contained in:
Joshua C. Colp
2020-01-05 00:11:20 +00:00
committed by Joshua Colp
parent a6de4497e6
commit 5a5be92b79
8 changed files with 566 additions and 149 deletions
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168
bridges/bridge_native_rtp.c
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@@ -43,6 +43,7 @@
#include "asterisk/bridge_technology.h"
#include "asterisk/frame.h"
#include "asterisk/rtp_engine.h"
#include "asterisk/stream.h"
/*! \brief Internal structure which contains bridged RTP channel hook data */
struct native_rtp_framehook_data {
@@ -85,6 +86,28 @@ struct native_rtp_bridge_channel_data {
struct rtp_glue_data glue;
};
/*! \brief Forward declarations */
static int native_rtp_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel);
static void native_rtp_bridge_unsuspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel);
static void native_rtp_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel);
static void native_rtp_bridge_suspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel);
static int native_rtp_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame);
static int native_rtp_bridge_compatible(struct ast_bridge *bridge);
static void native_rtp_stream_topology_changed(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel);
static struct ast_bridge_technology native_rtp_bridge = {
.name = "native_rtp",
.capabilities = AST_BRIDGE_CAPABILITY_NATIVE,
.preference = AST_BRIDGE_PREFERENCE_BASE_NATIVE,
.join = native_rtp_bridge_join,
.unsuspend = native_rtp_bridge_unsuspend,
.leave = native_rtp_bridge_leave,
.suspend = native_rtp_bridge_suspend,
.write = native_rtp_bridge_write,
.compatible = native_rtp_bridge_compatible,
.stream_topology_changed = native_rtp_stream_topology_changed,
};
static void rtp_glue_data_init(struct rtp_glue_data *glue)
{
glue->cb = NULL;
@@ -831,12 +854,124 @@ static void native_rtp_bridge_framehook_detach(struct ast_bridge_channel *bridge
data->hook_data = NULL;
}
static struct ast_stream_topology *native_rtp_request_stream_topology_update(
struct ast_stream_topology *existing_topology,
struct ast_stream_topology *requested_topology)
{
struct ast_stream *stream;
struct ast_format_cap *audio_formats = NULL;
struct ast_stream_topology *new_topology;
int i;
new_topology = ast_stream_topology_clone(requested_topology);
if (!new_topology) {
return NULL;
}
/* We find an existing stream with negotiated audio formats that we can place into
* any audio streams in the new topology to ensure that negotiation succeeds. Some
* endpoints incorrectly terminate the call if SDP negotiation fails.
*/
for (i = 0; i < ast_stream_topology_get_count(existing_topology); ++i) {
stream = ast_stream_topology_get_stream(existing_topology, i);
if (ast_stream_get_type(stream) != AST_MEDIA_TYPE_AUDIO ||
ast_stream_get_state(stream) == AST_STREAM_STATE_REMOVED) {
continue;
}
audio_formats = ast_stream_get_formats(stream);
break;
}
if (audio_formats) {
for (i = 0; i < ast_stream_topology_get_count(new_topology); ++i) {
stream = ast_stream_topology_get_stream(new_topology, i);
if (ast_stream_get_type(stream) != AST_MEDIA_TYPE_AUDIO ||
ast_stream_get_state(stream) == AST_STREAM_STATE_REMOVED) {
continue;
}
ast_format_cap_append_from_cap(ast_stream_get_formats(stream), audio_formats,
AST_MEDIA_TYPE_AUDIO);
}
}
for (i = 0; i < ast_stream_topology_get_count(new_topology); ++i) {
stream = ast_stream_topology_get_stream(new_topology, i);
/* For both recvonly and sendonly the stream state reflects our state, that is we
* are receiving only and we are sending only. Since we are renegotiating a remote
* party we need to swap this to reflect what we will be doing. That is, if we are
* receiving from Alice then we want to be sending to Bob, so swap recvonly to
* sendonly.
*/
if (ast_stream_get_state(stream) == AST_STREAM_STATE_RECVONLY) {
ast_stream_set_state(stream, AST_STREAM_STATE_SENDONLY);
} else if (ast_stream_get_state(stream) == AST_STREAM_STATE_SENDONLY) {
ast_stream_set_state(stream, AST_STREAM_STATE_RECVONLY);
}
}
return new_topology;
}
static void native_rtp_stream_topology_changed(struct ast_bridge *bridge,
struct ast_bridge_channel *bridge_channel)
{
struct ast_channel *c0 = bridge_channel->chan;
struct ast_channel *c1 = AST_LIST_FIRST(&bridge->channels)->chan;
struct ast_stream_topology *req_top;
struct ast_stream_topology *existing_top;
struct ast_stream_topology *new_top;
ast_bridge_channel_stream_map(bridge_channel);
if (ast_channel_get_stream_topology_change_source(bridge_channel->chan)
== &native_rtp_bridge) {
return;
}
if (c0 == c1) {
c1 = AST_LIST_LAST(&bridge->channels)->chan;
}
if (c0 == c1) {
return;
}
/* If a party renegotiates we want to renegotiate their counterpart to a matching
* topology.
*/
ast_channel_lock_both(c0, c1);
req_top = ast_channel_get_stream_topology(c0);
existing_top = ast_channel_get_stream_topology(c1);
new_top = native_rtp_request_stream_topology_update(existing_top, req_top);
ast_channel_unlock(c0);
ast_channel_unlock(c1);
if (!new_top) {
/* Failure. We'll just have to live with the current topology. */
return;
}
ast_channel_request_stream_topology_change(c1, new_top, &native_rtp_bridge);
ast_stream_topology_free(new_top);
}
/*!
* \internal
* \brief Called by the bridge core 'join' callback for each channel joining he bridge
*/
static int native_rtp_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
{
struct ast_stream_topology *req_top;
struct ast_stream_topology *existing_top;
struct ast_stream_topology *new_top;
struct ast_channel *c0 = AST_LIST_FIRST(&bridge->channels)->chan;
struct ast_channel *c1 = AST_LIST_LAST(&bridge->channels)->chan;
ast_debug(2, "Bridge '%s'. Channel '%s' is joining bridge tech\n",
bridge->uniqueid, ast_channel_name(bridge_channel->chan));
@@ -858,6 +993,27 @@ static int native_rtp_bridge_join(struct ast_bridge *bridge, struct ast_bridge_c
return -1;
}
if (c0 != c1) {
/* When both channels are joined we want to try to improve the experience by
* raising the number of streams so they match.
*/
ast_channel_lock_both(c0, c1);
req_top = ast_channel_get_stream_topology(c0);
existing_top = ast_channel_get_stream_topology(c1);
if (ast_stream_topology_get_count(req_top) < ast_stream_topology_get_count(existing_top)) {
SWAP(req_top, existing_top);
SWAP(c0, c1);
}
new_top = native_rtp_request_stream_topology_update(existing_top, req_top);
ast_channel_unlock(c0);
ast_channel_unlock(c1);
if (new_top) {
ast_channel_request_stream_topology_change(c1, new_top, &native_rtp_bridge);
ast_stream_topology_free(new_top);
}
}
native_rtp_bridge_start(bridge, NULL);
return 0;
}
@@ -939,18 +1095,6 @@ static int native_rtp_bridge_write(struct ast_bridge *bridge, struct ast_bridge_
return defer;
}
static struct ast_bridge_technology native_rtp_bridge = {
.name = "native_rtp",
.capabilities = AST_BRIDGE_CAPABILITY_NATIVE,
.preference = AST_BRIDGE_PREFERENCE_BASE_NATIVE,
.join = native_rtp_bridge_join,
.unsuspend = native_rtp_bridge_unsuspend,
.leave = native_rtp_bridge_leave,
.suspend = native_rtp_bridge_suspend,
.write = native_rtp_bridge_write,
.compatible = native_rtp_bridge_compatible,
};
static int unload_module(void)
{
ast_bridge_technology_unregister(&native_rtp_bridge);