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Add initial SDP state code.

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This establishes the basic allocation/destruction of an SDP state
object, plus some of the simpler getter methods involved. Subsequent
tasks will deal with adding a state machine, creating SDPs from
capabilities and options, and merging SDPs into a joint SDP.

Change-Id: Ie3757ce186f04b65e9d1883f5aace53f24e53709
This commit is contained in:
Mark Michelson
2017-02-15 14:43:36 -06:00
parent 5a130b2e17
commit a738772edd
2 changed files with 165 additions and 0 deletions
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58
include/asterisk/sdp_state.h Normal file
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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2017, Digium, Inc.
*
* Mark Michelson <mmichelson@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
#ifndef _ASTERISK_SDP_STATE_H
#define _ASTERISK_SDP_STATE_H
struct ast_sdp_state;
struct ast_sdp_options;
struct ast_stream_topology;
/*!
* \brief Allocate a new SDP state
*
* SDP state keeps tabs on everything SDP-related for a media session.
* Most SDP operations will require the state to be provided.
* Ownership of the SDP options is taken on by the SDP state.
* A good strategy is to call this during session creation.
*/
struct ast_sdp_state *ast_sdp_state_alloc(struct ast_stream_topology *streams, struct ast_sdp_options *options);
/*!
* \brief Free the SDP state.
*
* A good strategy is to call this during session destruction
*/
void ast_sdp_state_free(struct ast_sdp_state *sdp_state);
/*!
* \brief Get the associated RTP instance for a particular stream on the SDP state.
*
* Stream numbers correspond to the streams in the topology of the associated channel
*/
struct ast_rtp_instance *ast_sdp_state_get_rtp_instance(struct ast_sdp_state *sdp_state, int stream_index);
/*!
* \brief Get the joint negotiated streams based on local and remote capabilities.
*
* If this is called prior to receiving a remote SDP, then this will just mirror
* the local configured endpoint capabilities.
*/
struct ast_stream_topology *ast_sdp_state_get_joint_topology(struct ast_sdp_state *sdp_state);
#endif /* _ASTERISK_SDP_STATE_H */

107
main/sdp_state.c Normal file
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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2017, Digium, Inc.
*
* Mark Michelson <mmichelson@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
#include "asterisk.h"
#include "asterisk/sdp_state.h"
#include "asterisk/sdp_options.h"
#include "asterisk/sdp_translator.h"
#include "asterisk/sdp_priv.h"
#include "asterisk/vector.h"
#include "asterisk/utils.h"
#include "asterisk/stream.h"
struct ast_sdp_state {
/*! Local capabilities, learned through configuration */
struct ast_stream_topology *local_capabilities;
/*! Remote capabilities, learned through remote SDP */
struct ast_stream_topology *remote_capabilities;
/*! Joint capabilities. The combined local and remote capabilities. */
struct ast_stream_topology *joint_capabilities;
/*! Local SDP. Generated via the options and local capabilities. */
struct ast_sdp *local_sdp;
/*! Remote SDP. Received directly from a peer. */
struct ast_sdp *remote_sdp;
/*! Joint SDP. The merged local and remote SDPs. */
struct ast_sdp *joint_sdp;
/*! SDP options. Configured options beyond media capabilities. */
struct ast_sdp_options *options;
/*! Translator that puts SDPs into the expected representation */
struct ast_sdp_translator *translator;
/*! RTP instance for each media stream */
AST_VECTOR(, struct ast_rtp_instance *) rtp;
};
struct ast_sdp_state *ast_sdp_state_alloc(struct ast_stream_topology *streams, struct ast_sdp_options *options)
{
struct ast_sdp_state *sdp_state;
sdp_state = ast_calloc(1, sizeof(*sdp_state));
if (!sdp_state) {
return NULL;
}
sdp_state->options = options;
sdp_state->translator = ast_sdp_translator_new(ast_sdp_options_get_repr(sdp_state->options));
if (!sdp_state->translator) {
ast_sdp_state_free(sdp_state);
return NULL;
}
sdp_state->local_capabilities = ast_stream_topology_clone(streams);
if (!sdp_state->local_capabilities) {
ast_sdp_state_free(sdp_state);
return NULL;
}
return sdp_state;
}
void ast_sdp_state_free(struct ast_sdp_state *sdp_state)
{
if (!sdp_state) {
return;
}
ast_stream_topology_free(sdp_state->local_capabilities);
ast_stream_topology_free(sdp_state->remote_capabilities);
ast_stream_topology_free(sdp_state->joint_capabilities);
ast_sdp_free(sdp_state->local_sdp);
ast_sdp_free(sdp_state->remote_sdp);
ast_sdp_free(sdp_state->joint_sdp);
ast_sdp_options_free(sdp_state->options);
ast_sdp_translator_free(sdp_state->translator);
}
struct ast_rtp_instance *ast_sdp_state_get_rtp_instance(struct ast_sdp_state *sdp_state, int stream_index)
{
if (stream_index >= AST_VECTOR_SIZE(&sdp_state->rtp)) {
return NULL;
}
return AST_VECTOR_GET(&sdp_state->rtp, stream_index);
}
struct ast_stream_topology *ast_sdp_state_get_joint_topology(struct ast_sdp_state *sdp_state)
{
if (sdp_state->joint_capabilities) {
return sdp_state->joint_capabilities;
} else {
return sdp_state->local_capabilities;
}
}