add codec_mapping.h,c

Converting between different codec representations is confusing. This
codec mapping provides a consolidated overview of all our codec
representations, and how they match up.

In particular, it adds the SDP codec representation repertoire,
preparing the use of full SDP on the MNCC interface.

Related: SYS#5066
Change-Id: Iaa307be6a8487aa8d4ba7cd59d5c5ef04818a744
This commit is contained in:
Neels Hofmeyr 2022-01-13 18:17:56 +01:00 committed by neels
parent c43b01e918
commit b2ce74829a
4 changed files with 587 additions and 0 deletions

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@ -1,6 +1,7 @@
noinst_HEADERS = \
call_leg.h \
cell_id_list.h \
codec_mapping.h \
db.h \
debug.h \
e_link.h \

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@ -0,0 +1,64 @@
/* Routines for translation between codec representations: SDP, CC/BSSMAP variants, MGCP, MNCC */
#pragma once
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/gsm/protocol/gsm_08_08.h>
#include <osmocom/mgcp_client/mgcp_client.h>
#include <osmocom/msc/sdp_msg.h>
#include <osmocom/gsm/mncc.h>
#define NO_MGCP_CODEC 0xffffffff
extern const struct gsm_mncc_bearer_cap bearer_cap_empty;
enum codec_frhr {
CODEC_FRHR_NONE = 0,
CODEC_FRHR_FR,
CODEC_FRHR_HR,
};
struct codec_mapping {
/* The sdp.payload_type number in a mapping is not necessarily imperative, but may just reflect the usual
* payload type number for a given codec. */
struct sdp_audio_codec sdp;
/* The id that mgcp_client.h uses for this codec. Must be set in each mapping, because 0 means PCMU. */
enum mgcp_codecs mgcp;
/* Nr of used entries in speech_ver[] below. */
unsigned int speech_ver_count;
/* Entries to add to Speech Version lists when this codec is present, if any. */
enum gsm48_bcap_speech_ver speech_ver[8];
/* If applicable, one of GSM_TCHF_FRAME, GSM_TCHF_FRAME_EFR, GSM_TCHH_FRAME, GSM_TCH_FRAME_AMR; or zero. */
uint32_t mncc_payload_msg_type;
/* Set to true if gsm0808_speech_codec below reflects a meaningful value. */
bool has_gsm0808_speech_codec;
struct gsm0808_speech_codec gsm0808_speech_codec;
/* If applicable, entries to add to Permitted Speech lists when this codec is present; or zero. */
enum gsm0808_permitted_speech perm_speech;
/* If applicable, indicator whether this codec can work on a GERAN half-rate lchan, or whether full-rate is
* required. Leave zero when this codec does not apply to GERAN. */
enum codec_frhr frhr;
};
const struct codec_mapping *codec_mapping_by_speech_ver(enum gsm48_bcap_speech_ver speech_ver);
const struct codec_mapping *codec_mapping_by_gsm0808_speech_codec_type(enum gsm0808_speech_codec_type sct);
const struct codec_mapping *codec_mapping_by_gsm0808_speech_codec(const struct gsm0808_speech_codec *sc);
const struct codec_mapping *codec_mapping_by_perm_speech(enum gsm0808_permitted_speech perm_speech);
const struct codec_mapping *codec_mapping_by_subtype_name(const char *subtype_name);
const struct codec_mapping *codec_mapping_by_mgcp_codec(enum mgcp_codecs mgcp);
int bearer_cap_add_speech_ver(struct gsm_mncc_bearer_cap *bearer_cap, enum gsm48_bcap_speech_ver speech_ver);
int sdp_audio_codec_add_to_bearer_cap(struct gsm_mncc_bearer_cap *bearer_cap, const struct sdp_audio_codec *codec);
int sdp_audio_codecs_to_bearer_cap(struct gsm_mncc_bearer_cap *bearer_cap, const struct sdp_audio_codecs *ac);
int bearer_cap_set_radio(struct gsm_mncc_bearer_cap *bearer_cap);
struct sdp_audio_codec *sdp_audio_codecs_add_speech_ver(struct sdp_audio_codecs *ac,
enum gsm48_bcap_speech_ver speech_ver);
struct sdp_audio_codec *sdp_audio_codecs_add_mgcp_codec(struct sdp_audio_codecs *ac, enum mgcp_codecs mgcp_codec);
void sdp_audio_codecs_from_bearer_cap(struct sdp_audio_codecs *ac, const struct gsm_mncc_bearer_cap *bc);
void sdp_audio_codecs_to_speech_codec_list(struct gsm0808_speech_codec_list *cl, const struct sdp_audio_codecs *ac);
void sdp_audio_codecs_from_speech_codec_list(struct sdp_audio_codecs *ac, const struct gsm0808_speech_codec_list *cl);
int sdp_audio_codecs_to_gsm0808_channel_type(struct gsm0808_channel_type *ct, const struct sdp_audio_codecs *ac);
enum mgcp_codecs sdp_audio_codec_to_mgcp_codec(const struct sdp_audio_codec *codec);

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@ -27,6 +27,7 @@ noinst_LIBRARIES = \
libmsc_a_SOURCES = \
call_leg.c \
cell_id_list.c \
codec_mapping.c \
sccp_ran.c \
msc_vty.c \
db.c \

521
src/libmsc/codec_mapping.c Normal file
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@ -0,0 +1,521 @@
/* Routines for translation between codec representations: SDP, CC/BSSMAP variants, MGCP, MNCC */
/*
* (C) 2019-2023 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de>
* All Rights Reserved
*
* Author: Neels Hofmeyr
*
* SPDX-License-Identifier: AGPL-3.0+
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include <osmocom/gsm/mncc.h>
#include <osmocom/msc/sdp_msg.h>
#include <osmocom/msc/codec_mapping.h>
#include <osmocom/msc/mncc.h>
const struct codec_mapping codec_map[] = {
/* FIXME: sdp.fmtp handling is not done properly yet, proper mode-set and octet-align handling will follow in
* separate patches. */
{
.sdp = {
.payload_type = 0,
.subtype_name = "PCMU",
.rate = 8000,
},
.mgcp = CODEC_PCMU_8000_1,
},
{
.sdp = {
.payload_type = 3,
.subtype_name = "GSM",
.rate = 8000,
},
.mgcp = CODEC_GSM_8000_1,
.speech_ver_count = 1,
.speech_ver = { GSM48_BCAP_SV_FR },
.mncc_payload_msg_type = GSM_TCHF_FRAME,
.has_gsm0808_speech_codec = true,
.gsm0808_speech_codec = {
.fi = true,
.type = GSM0808_SCT_FR1,
},
.perm_speech = GSM0808_PERM_FR1,
.frhr = CODEC_FRHR_FR,
},
{
.sdp = {
.payload_type = 8,
.subtype_name = "PCMA",
.rate = 8000,
},
.mgcp = CODEC_PCMA_8000_1,
},
{
.sdp = {
.payload_type = 18,
.subtype_name = "G729",
.rate = 8000,
},
.mgcp = CODEC_G729_8000_1,
},
{
.sdp = {
.payload_type = 110,
.subtype_name = "GSM-EFR",
.rate = 8000,
},
.mgcp = CODEC_GSMEFR_8000_1,
.speech_ver_count = 1,
.speech_ver = { GSM48_BCAP_SV_EFR },
.mncc_payload_msg_type = GSM_TCHF_FRAME_EFR,
.has_gsm0808_speech_codec = true,
.gsm0808_speech_codec = {
.fi = true,
.type = GSM0808_SCT_FR2,
},
.perm_speech = GSM0808_PERM_FR2,
.frhr = CODEC_FRHR_FR,
},
{
.sdp = {
.payload_type = 111,
.subtype_name = "GSM-HR-08",
.rate = 8000,
},
.mgcp = CODEC_GSMHR_8000_1,
.speech_ver_count = 1,
.speech_ver = { GSM48_BCAP_SV_HR },
.mncc_payload_msg_type = GSM_TCHH_FRAME,
.has_gsm0808_speech_codec = true,
.gsm0808_speech_codec = {
.fi = true,
.type = GSM0808_SCT_HR1,
.cfg = GSM0808_SC_CFG_DEFAULT_HR_AMR,
},
.perm_speech = GSM0808_PERM_HR1,
.frhr = CODEC_FRHR_HR,
},
{
.sdp = {
.payload_type = 112,
.subtype_name = "AMR",
.rate = 8000,
/* AMR is always octet-aligned in 2G and 3G RAN, so this fmtp is signalled to remote call legs.
* So far, fmtp is ignored in incoming SIP SDP, so an incoming SDP without 'octet-align=1' will
* match with this entry; we will still reply with 'octet-align=1', which often works out. */
.fmtp = "octet-align=1",
},
.mgcp = CODEC_AMR_8000_1,
.speech_ver_count = 1,
.speech_ver = { GSM48_BCAP_SV_AMR_F },
.mncc_payload_msg_type = GSM_TCH_FRAME_AMR,
.has_gsm0808_speech_codec = true,
.gsm0808_speech_codec = {
.fi = true,
.type = GSM0808_SCT_FR3,
.cfg = GSM0808_SC_CFG_DEFAULT_FR_AMR,
},
.perm_speech = GSM0808_PERM_FR3,
.frhr = CODEC_FRHR_FR,
},
{
/* Another entry like the above, to map HR3 to AMR, too. */
.sdp = {
.payload_type = 112,
.subtype_name = "AMR",
.rate = 8000,
.fmtp = "octet-align=1",
},
.mgcp = CODEC_AMR_8000_1,
.speech_ver_count = 2,
.speech_ver = { GSM48_BCAP_SV_AMR_H, GSM48_BCAP_SV_AMR_OH },
.mncc_payload_msg_type = GSM_TCH_FRAME_AMR,
.has_gsm0808_speech_codec = true,
.gsm0808_speech_codec = {
.fi = true,
.type = GSM0808_SCT_HR3,
.cfg = GSM0808_SC_CFG_DEFAULT_HR_AMR,
},
.perm_speech = GSM0808_PERM_HR3,
.frhr = CODEC_FRHR_HR,
},
{
.sdp = {
.payload_type = 113,
.subtype_name = "AMR-WB",
.rate = 16000,
.fmtp = "octet-align=1",
},
.mgcp = CODEC_AMRWB_16000_1,
.speech_ver_count = 2,
.speech_ver = { GSM48_BCAP_SV_AMR_OFW, GSM48_BCAP_SV_AMR_FW },
.mncc_payload_msg_type = GSM_TCH_FRAME_AMR,
.has_gsm0808_speech_codec = true,
.gsm0808_speech_codec = {
.fi = true,
.type = GSM0808_SCT_FR5,
.cfg = GSM0808_SC_CFG_DEFAULT_FR_AMR_WB,
},
.perm_speech = GSM0808_PERM_FR5,
.frhr = CODEC_FRHR_FR,
},
{
/* Another entry like the above, to map HR4 to AMR-WB, too. */
.sdp = {
.payload_type = 113,
.subtype_name = "AMR-WB",
.rate = 16000,
.fmtp = "octet-align=1",
},
.mgcp = CODEC_AMRWB_16000_1,
.speech_ver_count = 1,
.speech_ver = { GSM48_BCAP_SV_AMR_OHW },
.mncc_payload_msg_type = GSM_TCH_FRAME_AMR,
.has_gsm0808_speech_codec = true,
.gsm0808_speech_codec = {
.fi = true,
.type = GSM0808_SCT_HR4,
.cfg = GSM0808_SC_CFG_DEFAULT_OHR_AMR_WB,
},
.perm_speech = GSM0808_PERM_HR4,
.frhr = CODEC_FRHR_HR,
},
{
.sdp = {
.payload_type = 96,
.subtype_name = "VND.3GPP.IUFP",
.rate = 16000,
},
.mgcp = CODEC_IUFP,
},
};
#define foreach_codec_mapping(CODEC_MAPPING) \
for ((CODEC_MAPPING) = codec_map; (CODEC_MAPPING) < codec_map + ARRAY_SIZE(codec_map); (CODEC_MAPPING)++)
const struct gsm_mncc_bearer_cap bearer_cap_empty = {
.speech_ver = { -1 },
};
const struct codec_mapping *codec_mapping_by_speech_ver(enum gsm48_bcap_speech_ver speech_ver)
{
const struct codec_mapping *m;
foreach_codec_mapping(m) {
int i;
for (i = 0; i < m->speech_ver_count; i++)
if (m->speech_ver[i] == speech_ver)
return m;
}
return NULL;
}
const struct codec_mapping *codec_mapping_by_gsm0808_speech_codec_type(enum gsm0808_speech_codec_type sct)
{
const struct codec_mapping *m;
foreach_codec_mapping(m) {
if (!m->has_gsm0808_speech_codec)
continue;
if (m->gsm0808_speech_codec.type == sct)
return m;
}
return NULL;
}
const struct codec_mapping *codec_mapping_by_gsm0808_speech_codec(const struct gsm0808_speech_codec *sc)
{
const struct codec_mapping *m;
foreach_codec_mapping(m) {
if (!m->has_gsm0808_speech_codec)
continue;
if (m->gsm0808_speech_codec.type != sc->type)
continue;
/* Return only those where sc->cfg is a subset of m->gsm0808_speech_codec.cfg. */
if ((m->gsm0808_speech_codec.cfg & sc->cfg) != sc->cfg)
continue;
return m;
}
return NULL;
}
const struct codec_mapping *codec_mapping_by_perm_speech(enum gsm0808_permitted_speech perm_speech)
{
const struct codec_mapping *m;
foreach_codec_mapping(m) {
if (m->perm_speech == perm_speech)
return m;
}
return NULL;
}
const struct codec_mapping *codec_mapping_by_subtype_name(const char *subtype_name)
{
const struct codec_mapping *m;
foreach_codec_mapping(m) {
if (!strcmp(m->sdp.subtype_name, subtype_name))
return m;
}
return NULL;
}
const struct codec_mapping *codec_mapping_by_mgcp_codec(enum mgcp_codecs mgcp)
{
const struct codec_mapping *m;
foreach_codec_mapping(m) {
if (m->mgcp == mgcp)
return m;
}
return NULL;
}
/* Append given Speech Version to the end of the Bearer Capabilities Speech Version array. Return 1 if added, zero
* otherwise (as in, return the number of items added). */
int bearer_cap_add_speech_ver(struct gsm_mncc_bearer_cap *bearer_cap, enum gsm48_bcap_speech_ver speech_ver)
{
int i;
for (i = 0; i < ARRAY_SIZE(bearer_cap->speech_ver) - 1; i++) {
if (bearer_cap->speech_ver[i] == speech_ver)
return 0;
if (bearer_cap->speech_ver[i] == -1) {
bearer_cap->speech_ver[i] = speech_ver;
bearer_cap->speech_ver[i+1] = -1;
return 1;
}
}
return 0;
}
/* From the current speech_ver list present in the bearer_cap, set the bearer_cap.radio.
* If a HR speech_ver is present, set to GSM48_BCAP_RRQ_DUAL_FR, otherwise set to GSM48_BCAP_RRQ_FR_ONLY. */
int bearer_cap_set_radio(struct gsm_mncc_bearer_cap *bearer_cap)
{
bool hr_present = false;
int i;
for (i = 0; i < ARRAY_SIZE(bearer_cap->speech_ver) - 1; i++) {
const struct codec_mapping *m;
if (bearer_cap->speech_ver[i] == -1)
break;
m = codec_mapping_by_speech_ver(bearer_cap->speech_ver[i]);
if (!m)
continue;
if (m->frhr == CODEC_FRHR_HR)
hr_present = true;
}
if (hr_present)
bearer_cap->radio = GSM48_BCAP_RRQ_DUAL_FR;
else
bearer_cap->radio = GSM48_BCAP_RRQ_FR_ONLY;
return 0;
}
/* Try to convert the SDP audio codec name to Speech Versions to append to Bearer Capabilities.
* Return the number of Speech Version entries added (some may add more than one, others may be unknown/unapplicable and
* return 0). */
int sdp_audio_codec_add_to_bearer_cap(struct gsm_mncc_bearer_cap *bearer_cap, const struct sdp_audio_codec *codec)
{
const struct codec_mapping *m;
int added = 0;
foreach_codec_mapping(m) {
int i;
if (strcmp(m->sdp.subtype_name, codec->subtype_name))
continue;
/* TODO also match rate and fmtp? */
for (i = 0; i < m->speech_ver_count; i++)
added += bearer_cap_add_speech_ver(bearer_cap, m->speech_ver[i]);
}
return added;
}
/* Append all audio codecs found in given sdp_msg to Bearer Capability, by traversing all codec entries with
* sdp_audio_codec_add_to_bearer_cap(). Return the number of Speech Version entries added.
* Note that Speech Version entries are only appended, no previous entries are removed.
* Note that only the Speech Version entries are modified; to make a valid Bearer Capabiliy, at least bearer_cap->radio
* must also be set (before or after this function); see also bearer_cap_set_radio(). */
int sdp_audio_codecs_to_bearer_cap(struct gsm_mncc_bearer_cap *bearer_cap, const struct sdp_audio_codecs *ac)
{
const struct sdp_audio_codec *codec;
int added = 0;
foreach_sdp_audio_codec(codec, ac) {
added += sdp_audio_codec_add_to_bearer_cap(bearer_cap, codec);
}
return added;
}
/* Convert Speech Version to SDP audio codec and append to SDP message struct. */
struct sdp_audio_codec *sdp_audio_codecs_add_speech_ver(struct sdp_audio_codecs *ac,
enum gsm48_bcap_speech_ver speech_ver)
{
const struct codec_mapping *m;
struct sdp_audio_codec *ret = NULL;
foreach_codec_mapping(m) {
int i;
for (i = 0; i < m->speech_ver_count; i++) {
if (m->speech_ver[i] == speech_ver) {
ret = sdp_audio_codecs_add_copy(ac, &m->sdp);
break;
}
}
}
return ret;
}
struct sdp_audio_codec *sdp_audio_codecs_add_mgcp_codec(struct sdp_audio_codecs *ac, enum mgcp_codecs mgcp_codec)
{
const struct codec_mapping *m = codec_mapping_by_mgcp_codec(mgcp_codec);
if (!m)
return NULL;
return sdp_audio_codecs_add_copy(ac, &m->sdp);
}
void sdp_audio_codecs_from_bearer_cap(struct sdp_audio_codecs *ac, const struct gsm_mncc_bearer_cap *bc)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(bc->speech_ver); i++) {
if (bc->speech_ver[i] == -1)
break;
sdp_audio_codecs_add_speech_ver(ac, bc->speech_ver[i]);
}
}
void sdp_audio_codecs_to_speech_codec_list(struct gsm0808_speech_codec_list *scl, const struct sdp_audio_codecs *ac)
{
const struct sdp_audio_codec *codec;
*scl = (struct gsm0808_speech_codec_list){};
foreach_sdp_audio_codec(codec, ac) {
const struct codec_mapping *m = codec_mapping_by_subtype_name(codec->subtype_name);
if (!m)
continue;
if (!m->has_gsm0808_speech_codec)
continue;
if (scl->len >= ARRAY_SIZE(scl->codec))
break;
scl->codec[scl->len] = m->gsm0808_speech_codec;
/* FIXME: apply AMR configuration according to codec->fmtp */
scl->len++;
}
}
void sdp_audio_codecs_from_speech_codec_list(struct sdp_audio_codecs *ac, const struct gsm0808_speech_codec_list *cl)
{
int i;
for (i = 0; i < cl->len; i++) {
const struct gsm0808_speech_codec *sc = &cl->codec[i];
const struct codec_mapping *m = codec_mapping_by_gsm0808_speech_codec(sc);
if (!m)
continue;
sdp_audio_codecs_add_copy(ac, &m->sdp);
/* FIXME: for AMR, apply sc->cfg to the added codec's fmtp */
}
}
int sdp_audio_codecs_to_gsm0808_channel_type(struct gsm0808_channel_type *ct, const struct sdp_audio_codecs *ac)
{
const struct sdp_audio_codec *codec;
bool fr_present = false;
int first_fr_idx = -1;
bool hr_present = false;
int first_hr_idx = -1;
int idx = -1;
*ct = (struct gsm0808_channel_type){
.ch_indctr = GSM0808_CHAN_SPEECH,
};
foreach_sdp_audio_codec(codec, ac) {
const struct codec_mapping *m;
int i;
bool dup;
idx++;
foreach_codec_mapping(m) {
if (strcmp(m->sdp.subtype_name, codec->subtype_name))
continue;
switch (m->perm_speech) {
default:
continue;
case GSM0808_PERM_FR1:
case GSM0808_PERM_FR2:
case GSM0808_PERM_FR3:
case GSM0808_PERM_FR4:
case GSM0808_PERM_FR5:
fr_present = true;
if (first_fr_idx < 0)
first_fr_idx = idx;
break;
case GSM0808_PERM_HR1:
case GSM0808_PERM_HR2:
case GSM0808_PERM_HR3:
case GSM0808_PERM_HR4:
case GSM0808_PERM_HR6:
hr_present = true;
if (first_hr_idx < 0)
first_hr_idx = idx;
break;
}
/* Avoid duplicates */
dup = false;
for (i = 0; i < ct->perm_spch_len; i++) {
if (ct->perm_spch[i] == m->perm_speech) {
dup = true;
break;
}
}
if (dup)
continue;
ct->perm_spch[ct->perm_spch_len] = m->perm_speech;
ct->perm_spch_len++;
}
}
if (fr_present && hr_present) {
if (first_fr_idx <= first_hr_idx)
ct->ch_rate_type = GSM0808_SPEECH_FULL_PREF;
else
ct->ch_rate_type = GSM0808_SPEECH_HALF_PREF;
} else if (fr_present && !hr_present)
ct->ch_rate_type = GSM0808_SPEECH_FULL_BM;
else if (!fr_present && hr_present)
ct->ch_rate_type = GSM0808_SPEECH_HALF_LM;
else
return -EINVAL;
return 0;
}
enum mgcp_codecs sdp_audio_codec_to_mgcp_codec(const struct sdp_audio_codec *codec)
{
const struct codec_mapping *m;
foreach_codec_mapping(m) {
if (!sdp_audio_codec_cmp(&m->sdp, codec, false, false))
return m->mgcp;
}
return NO_MGCP_CODEC;
}