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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);
/*!
* \brief Get the local SDP.
*
* If we have not received a remote SDP yet, this will be an SDP offer based
* on known streams and options If we have received a remote SDP, this will
* be the negotiated SDP based on the joint capabilities. The return type is
* a void pointer because the representation of the SDP is going to be determined based
* on the SDP options when allocating the SDP state.
*
* This function will allocate RTP instances if RTP instances have not already
* been allocated for the streams.
*
* The return here is const. The use case for this is so that a channel can add the SDP to an outgoing
* message. The API user should not attempt to modify the SDP. SDP modification should only be done through
* the API.
*/
const void *ast_sdp_state_get_local(struct ast_sdp_state *sdp_state);
/*!
* \brief Set the remote SDP.
*
* This can be used for either a remote offer or answer.
* This can also be used whenever an UPDATE, re-INVITE, etc. arrives.
* The type of the "remote" parameter is dictated by whatever SDP representation
* was set in the ast_sdp_options used during ast_sdp_state allocation
*
* This function will NOT allocate RTP instances.
*/
int ast_sdp_state_set_remote(struct ast_sdp_state *sdp_state, void *remote);
/*!
* \brief Reset the SDP state and stream capabilities as if the SDP state had just been allocated.
*
* This is most useful for when a channel driver is sending a session refresh message
* and needs to re-advertise its initial capabilities instead of the previously-negotiated
* joint capabilities.
*/
int ast_sdp_state_reset(struct ast_sdp_state *sdp_state);
#endif /* _ASTERISK_SDP_STATE_H */
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