67 lines
3.0 KiB
C
67 lines
3.0 KiB
C
/* Filter/overlay codec selections for a voice call, across MS, RAN and CN limitations */
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/*
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* (C) 2019-2022 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de>
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* All Rights Reserved
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*
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* Author: Neels Hofmeyr
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#pragma once
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#include <osmocom/gsm/gsm_utils.h>
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#include <osmocom/gsm/mncc.h>
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#include <osmocom/mgcp_client/mgcp_client.h>
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#include <osmocom/msc/sdp_msg.h>
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struct gsm0808_speech_codec_list;
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/* Combine various codec selections to obtain a resulting set of codecs allowed by all of them.
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* Members reflect the different entities/stages that select codecs in a voice call.
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* Call codec_filter_run() and obtain the resulting set of codecs in codec_filter.result. */
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struct codec_filter {
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/* The fixed set of codecs available on the RAN type, per definition. */
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struct sdp_audio_codecs ran;
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/* The codecs advertised by the MS Bearer Capabilities */
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struct sdp_audio_codecs ms;
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/* If known, the set of codecs the current RAN cell allows / has available.
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* This may not be available if the BSC does not issue this information early enough.
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* Should be ignored if empty. */
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struct sdp_audio_codecs bss;
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/* SDP as last received from the remote call leg. */
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struct sdp_msg remote;
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/* After a channel was assigned, this reflects the chosen codec. */
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struct sdp_audio_codec assignment;
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/* Resulting choice of supported codecs, usually the intersection of the above,
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* and the local RTP address to be sent to the remote call leg.
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* The RTP address:port in result.rtp is not modified by codec_filter_run() -- set it once. */
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struct sdp_msg result;
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};
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void codec_filter_init(struct codec_filter *codec_filter);
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void codec_filter_set_ran(struct codec_filter *codec_filter, enum osmo_rat_type ran_type);
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void codec_filter_set_ms_from_bc(struct codec_filter *codec_filter, const struct gsm_mncc_bearer_cap *ms_bearer_cap);
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void codec_filter_set_bss(struct codec_filter *codec_filter,
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const struct gsm0808_speech_codec_list *codec_list_bss_supported);
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int codec_filter_set_remote(struct codec_filter *codec_filter, const char *remote_sdp);
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void codec_filter_set_local_rtp(struct codec_filter *codec_filter, const struct osmo_sockaddr_str *rtp);
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int codec_filter_run(struct codec_filter *codec_filter);
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int codec_filter_to_str_buf(char *buf, size_t buflen, const struct codec_filter *codec_filter);
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char *codec_filter_to_str_c(void *ctx, const struct codec_filter *codec_filter);
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const char *codec_filter_to_str(const struct codec_filter *codec_filter);
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