Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 1 | /* Filter/overlay codec selections for a voice call, across MS, RAN and CN limitations */ |
| 2 | /* |
Vadim Yanitskiy | 999a593 | 2023-05-18 17:22:26 +0700 | [diff] [blame] | 3 | * (C) 2019-2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 4 | * All Rights Reserved |
| 5 | * |
| 6 | * Author: Neels Hofmeyr |
| 7 | * |
| 8 | * SPDX-License-Identifier: AGPL-3.0+ |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU Affero General Public License as published by |
| 12 | * the Free Software Foundation; either version 3 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU Affero General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU Affero General Public License |
| 21 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 22 | */ |
| 23 | |
| 24 | #include <osmocom/gsm/protocol/gsm_08_08.h> |
| 25 | |
| 26 | #include <osmocom/msc/codec_filter.h> |
| 27 | #include <osmocom/msc/codec_mapping.h> |
| 28 | #include <osmocom/msc/debug.h> |
| 29 | |
| 30 | /* Add all known payload types encountered in GSM networks */ |
| 31 | static void sdp_add_all_geran_codecs(struct sdp_audio_codecs *ac) |
| 32 | { |
| 33 | /* In order of preference. TODO: make configurable */ |
| 34 | static const enum gsm48_bcap_speech_ver mobile_codecs[] = { |
| 35 | GSM48_BCAP_SV_AMR_F /*!< 4 GSM FR V3 (FR AMR) */, |
| 36 | GSM48_BCAP_SV_AMR_H /*!< 5 GSM HR V3 (HR_AMR) */, |
| 37 | GSM48_BCAP_SV_EFR /*!< 2 GSM FR V2 (GSM EFR) */, |
| 38 | GSM48_BCAP_SV_FR /*!< 0 GSM FR V1 (GSM FR) */, |
| 39 | GSM48_BCAP_SV_HR /*!< 1 GSM HR V1 (GSM HR) */, |
| 40 | }; |
| 41 | int i; |
| 42 | for (i = 0; i < ARRAY_SIZE(mobile_codecs); i++) |
| 43 | sdp_audio_codecs_add_speech_ver(ac, mobile_codecs[i]); |
| 44 | } |
| 45 | |
| 46 | /* Add all known AMR payload types encountered in UTRAN networks */ |
| 47 | static void sdp_add_all_utran_codecs(struct sdp_audio_codecs *ac) |
| 48 | { |
| 49 | /* In order of preference. TODO: make configurable */ |
| 50 | static const enum gsm48_bcap_speech_ver utran_codecs[] = { |
| 51 | GSM48_BCAP_SV_AMR_F /*!< 4 GSM FR V3 (FR AMR) */, |
| 52 | GSM48_BCAP_SV_AMR_H /*!< 5 GSM HR V3 (HR_AMR) */, |
| 53 | GSM48_BCAP_SV_AMR_OH /*!< 11 GSM HR V6 (OHR AMR) */, |
| 54 | GSM48_BCAP_SV_AMR_FW /*!< 8 GSM FR V5 (FR AMR-WB) */, |
| 55 | GSM48_BCAP_SV_AMR_OFW /*!< 6 GSM FR V4 (OFR AMR-WB) */, |
| 56 | GSM48_BCAP_SV_AMR_OHW /*!< 7 GSM HR V4 (OHR AMR-WB) */, |
| 57 | }; |
| 58 | int i; |
| 59 | for (i = 0; i < ARRAY_SIZE(utran_codecs); i++) |
| 60 | sdp_audio_codecs_add_speech_ver(ac, utran_codecs[i]); |
| 61 | } |
| 62 | |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 63 | void codec_filter_set_ran(struct codec_filter *codec_filter, enum osmo_rat_type ran_type) |
| 64 | { |
| 65 | codec_filter->ran = (struct sdp_audio_codecs){}; |
| 66 | |
| 67 | switch (ran_type) { |
| 68 | default: |
| 69 | case OSMO_RAT_GERAN_A: |
| 70 | sdp_add_all_geran_codecs(&codec_filter->ran); |
| 71 | break; |
| 72 | |
| 73 | case OSMO_RAT_UTRAN_IU: |
| 74 | sdp_add_all_utran_codecs(&codec_filter->ran); |
| 75 | break; |
| 76 | } |
| 77 | } |
| 78 | |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 79 | void codec_filter_set_bss(struct codec_filter *codec_filter, |
| 80 | const struct gsm0808_speech_codec_list *codec_list_bss_supported) |
| 81 | { |
| 82 | codec_filter->bss = (struct sdp_audio_codecs){}; |
| 83 | if (codec_list_bss_supported) |
| 84 | sdp_audio_codecs_from_speech_codec_list(&codec_filter->bss, codec_list_bss_supported); |
| 85 | } |
| 86 | |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 87 | /* Render intersections of all known audio codec constraints to reach a resulting choice of favorite audio codec, plus |
| 88 | * possible set of alternative audio codecs, in codec_filter->result. (The result.rtp address remains unchanged.) */ |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 89 | int codec_filter_run(struct codec_filter *codec_filter, struct sdp_msg *result, const struct sdp_msg *remote) |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 90 | { |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 91 | struct sdp_audio_codecs *r = &result->audio_codecs; |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 92 | struct sdp_audio_codec *a = &codec_filter->assignment; |
| 93 | *r = codec_filter->ran; |
| 94 | if (codec_filter->ms.count) |
| 95 | sdp_audio_codecs_intersection(r, &codec_filter->ms, false); |
| 96 | if (codec_filter->bss.count) |
| 97 | sdp_audio_codecs_intersection(r, &codec_filter->bss, false); |
Oliver Smith | 593cd88 | 2023-05-24 10:40:19 +0200 | [diff] [blame] | 98 | if (remote->audio_codecs.count) |
| 99 | sdp_audio_codecs_intersection(r, &remote->audio_codecs, true); |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 100 | |
| 101 | #if 0 |
| 102 | /* Future: If osmo-msc were able to trigger a re-assignment after the remote side has picked a codec mismatching |
| 103 | * the initial Assignment, then this code here would make sense: keep the other codecs as available to choose |
| 104 | * from, but put the currently assigned codec in the first position. So far we only offer the single assigned |
| 105 | * codec, because we have no way to deal with the remote side picking a different codec. |
| 106 | * Another approach would be to postpone assignment until we know the codecs from the remote side. */ |
| 107 | if (sdp_audio_codec_is_set(a)) { |
| 108 | /* Assignment has completed, the chosen codec should be the first of the resulting SDP. |
| 109 | * Make sure this is actually listed in the result SDP and move to first place. */ |
| 110 | struct sdp_audio_codec *select = sdp_audio_codecs_by_descr(r, a); |
| 111 | |
| 112 | if (!select) { |
| 113 | /* Not present. Add. */ |
| 114 | if (sdp_audio_codec_by_payload_type(r, a->payload_type, false)) { |
| 115 | /* Oh crunch, that payload type number is already in use. |
| 116 | * Find an unused one. */ |
| 117 | for (a->payload_type = 96; a->payload_type <= 127; a->payload_type++) { |
| 118 | if (!sdp_audio_codec_by_payload_type(r, a->payload_type, false)) |
| 119 | break; |
| 120 | } |
| 121 | |
| 122 | if (a->payload_type > 127) |
| 123 | return -ENOSPC; |
| 124 | } |
| 125 | select = sdp_audio_codecs_add_copy(r, a); |
| 126 | } |
| 127 | |
| 128 | sdp_audio_codecs_select(r, select); |
| 129 | } |
| 130 | #else |
| 131 | /* Currently, osmo-msc does not trigger re-assignment if the remote side has picked a codec that is different |
| 132 | * from the already assigned codec. |
| 133 | * So, if locally, Assignment has already chosen a codec, this is the single definitive result to be used |
| 134 | * towards the CN. */ |
| 135 | if (sdp_audio_codec_is_set(a)) { |
| 136 | /* Assignment has completed, the chosen codec should be the the only possible one. */ |
| 137 | *r = (struct sdp_audio_codecs){}; |
| 138 | sdp_audio_codecs_add_copy(r, a); |
| 139 | } |
| 140 | #endif |
| 141 | return 0; |
| 142 | } |
| 143 | |
Oliver Smith | 593cd88 | 2023-05-24 10:40:19 +0200 | [diff] [blame] | 144 | int codec_filter_to_str_buf(char *buf, size_t buflen, const struct codec_filter *codec_filter, |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 145 | const struct sdp_msg *result, const struct sdp_msg *remote) |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 146 | { |
| 147 | struct osmo_strbuf sb = { .buf = buf, .len = buflen }; |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 148 | OSMO_STRBUF_APPEND(sb, sdp_msg_to_str_buf, result); |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 149 | OSMO_STRBUF_PRINTF(sb, " (from:"); |
| 150 | |
| 151 | if (sdp_audio_codec_is_set(&codec_filter->assignment)) { |
| 152 | OSMO_STRBUF_PRINTF(sb, " assigned="); |
| 153 | OSMO_STRBUF_APPEND(sb, sdp_audio_codec_to_str_buf, &codec_filter->assignment); |
| 154 | } |
| 155 | |
Oliver Smith | 593cd88 | 2023-05-24 10:40:19 +0200 | [diff] [blame] | 156 | if (remote->audio_codecs.count |
| 157 | || osmo_sockaddr_str_is_nonzero(&remote->rtp)) { |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 158 | OSMO_STRBUF_PRINTF(sb, " remote="); |
Oliver Smith | 593cd88 | 2023-05-24 10:40:19 +0200 | [diff] [blame] | 159 | OSMO_STRBUF_APPEND(sb, sdp_msg_to_str_buf, remote); |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 160 | } |
| 161 | |
| 162 | if (codec_filter->ms.count) { |
| 163 | OSMO_STRBUF_PRINTF(sb, " MS={"); |
| 164 | OSMO_STRBUF_APPEND(sb, sdp_audio_codecs_to_str_buf, &codec_filter->ms); |
| 165 | OSMO_STRBUF_PRINTF(sb, "}"); |
| 166 | } |
| 167 | |
| 168 | if (codec_filter->bss.count) { |
| 169 | OSMO_STRBUF_PRINTF(sb, " bss={"); |
| 170 | OSMO_STRBUF_APPEND(sb, sdp_audio_codecs_to_str_buf, &codec_filter->bss); |
| 171 | OSMO_STRBUF_PRINTF(sb, "}"); |
| 172 | } |
| 173 | |
| 174 | OSMO_STRBUF_PRINTF(sb, " RAN={"); |
| 175 | OSMO_STRBUF_APPEND(sb, sdp_audio_codecs_to_str_buf, &codec_filter->ran); |
| 176 | OSMO_STRBUF_PRINTF(sb, "}"); |
| 177 | |
| 178 | OSMO_STRBUF_PRINTF(sb, ")"); |
| 179 | |
| 180 | return sb.chars_needed; |
| 181 | } |
| 182 | |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 183 | char *codec_filter_to_str_c(void *ctx, const struct codec_filter *codec_filter, const struct sdp_msg *result, |
| 184 | const struct sdp_msg *remote) |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 185 | { |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 186 | OSMO_NAME_C_IMPL(ctx, 128, "codec_filter_to_str_c-ERROR", codec_filter_to_str_buf, codec_filter, result, remote) |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 187 | } |
| 188 | |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 189 | const char *codec_filter_to_str(const struct codec_filter *codec_filter, const struct sdp_msg *result, |
| 190 | const struct sdp_msg *remote) |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 191 | { |
Oliver Smith | c63c3a0 | 2023-05-24 10:48:07 +0200 | [diff] [blame] | 192 | return codec_filter_to_str_c(OTC_SELECT, codec_filter, result, remote); |
Neels Hofmeyr | 63881a3 | 2022-01-13 18:34:52 +0100 | [diff] [blame] | 193 | } |