422 lines
13 KiB
C
422 lines
13 KiB
C
/*
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* (C) 2017-2018 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
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* All Rights Reserved
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*
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* Author: Philipp Maier
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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 Affero General Public License as published by
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* the Free Software Foundation; either version 3 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 Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <osmocom/core/msgb.h>
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#include <osmocom/gsm/protocol/gsm_08_08.h>
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#include <osmocom/gsm/gsm0808_utils.h>
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#include <osmocom/bsc/bsc_msc_data.h>
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#include <osmocom/bsc/codec_pref.h>
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#include <osmocom/bsc/gsm_data.h>
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/* Determine whether a permitted speech value is specifies a half rate or full
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* rate codec */
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static int full_rate_from_perm_spch(bool * full_rate,
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enum gsm0808_permitted_speech perm_spch)
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{
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/* Check if the result is a half or full rate codec */
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switch (perm_spch) {
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case GSM0808_PERM_HR1:
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case GSM0808_PERM_HR2:
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case GSM0808_PERM_HR3:
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case GSM0808_PERM_HR4:
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case GSM0808_PERM_HR6:
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*full_rate = false;
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break;
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case GSM0808_PERM_FR1:
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case GSM0808_PERM_FR2:
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case GSM0808_PERM_FR3:
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case GSM0808_PERM_FR4:
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case GSM0808_PERM_FR5:
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*full_rate = true;
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break;
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default:
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LOGP(DMSC, LOGL_ERROR, "Invalid permitted-speech value: %u\n",
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perm_spch);
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return -EINVAL;
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}
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return 0;
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}
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/* Helper function for match_codec_pref(), looks up a matching chan mode for
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* a given permitted speech value */
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static enum gsm48_chan_mode gsm88_to_chan_mode(enum gsm0808_permitted_speech speech)
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{
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switch (speech) {
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case GSM0808_PERM_HR1:
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case GSM0808_PERM_FR1:
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return GSM48_CMODE_SPEECH_V1;
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break;
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case GSM0808_PERM_FR2:
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return GSM48_CMODE_SPEECH_EFR;
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break;
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case GSM0808_PERM_HR3:
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case GSM0808_PERM_FR3:
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return GSM48_CMODE_SPEECH_AMR;
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break;
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case GSM0808_PERM_HR2:
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LOGP(DMSC, LOGL_FATAL, "Speech HR2 was never specified!\n");
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/* fall through */
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default:
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LOGP(DMSC, LOGL_FATAL, "Unsupported permitted speech %s selected, "
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"assuming AMR as channel mode...\n",
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gsm0808_permitted_speech_name(speech));
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return GSM48_CMODE_SPEECH_AMR;
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}
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}
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/* Helper function for match_codec_pref(), looks up a matching permitted speech
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* value for a given msc audio codec pref */
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static enum gsm0808_permitted_speech audio_support_to_gsm88(const struct gsm_audio_support *audio)
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{
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if (audio->hr) {
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switch (audio->ver) {
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case 1:
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return GSM0808_PERM_HR1;
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break;
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case 2:
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return GSM0808_PERM_HR2;
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break;
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case 3:
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return GSM0808_PERM_HR3;
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break;
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default:
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LOGP(DMSC, LOGL_ERROR, "Wrong speech mode: hr%d, using hr1 instead\n", audio->ver);
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return GSM0808_PERM_HR1;
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}
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} else {
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switch (audio->ver) {
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case 1:
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return GSM0808_PERM_FR1;
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break;
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case 2:
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return GSM0808_PERM_FR2;
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break;
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case 3:
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return GSM0808_PERM_FR3;
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break;
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default:
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LOGP(DMSC, LOGL_ERROR, "Wrong speech mode: fr%d, using fr1 instead\n", audio->ver);
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return GSM0808_PERM_FR1;
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}
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}
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}
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/* Helper function for match_codec_pref(), tests if a given audio support
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* matches one of the permitted speech settings of the channel type element.
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* The matched permitted speech value is then also compared against the
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* speech codec list. (optional, only relevant for AoIP) */
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static bool test_codec_pref(const struct gsm0808_speech_codec **sc_match,
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const struct gsm0808_speech_codec_list *scl,
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const struct gsm0808_channel_type *ct,
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uint8_t perm_spch)
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{
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unsigned int i;
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bool match = false;
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struct gsm0808_speech_codec sc;
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int rc;
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*sc_match = NULL;
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/* Try to find the given permitted speech value in the
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* codec list of the channel type element */
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for (i = 0; i < ct->perm_spch_len; i++) {
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if (ct->perm_spch[i] == perm_spch) {
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match = true;
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break;
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}
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}
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/* If we do not have a speech codec list to test against,
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* we just exit early (will be always the case in non-AoIP networks) */
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if (!scl || !scl->len)
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return match;
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/* If we failed to match until here, there is no
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* point in testing further */
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if (match == false)
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return false;
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/* Extrapolate speech codec data */
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rc = gsm0808_speech_codec_from_chan_type(&sc, perm_spch);
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if (rc < 0)
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return false;
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/* Try to find extrapolated speech codec data in
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* the speech codec list */
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for (i = 0; i < scl->len; i++) {
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if (sc.type == scl->codec[i].type) {
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*sc_match = &scl->codec[i];
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return true;
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}
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}
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return false;
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}
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/* Helper function to check if the given permitted speech value is supported
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* by the BTS. (vty option bts->codec-support). */
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static bool test_codec_support_bts(const struct gsm_bts *bts, uint8_t perm_spch)
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{
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struct gsm_bts_trx *trx;
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const struct bts_codec_conf *bts_codec = &bts->codec;
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unsigned int i;
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bool full_rate;
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int rc;
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enum gsm_phys_chan_config pchan;
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bool rate_match = false;
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/* Check if the BTS provides a physical channel that matches the
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* bandwith of the desired codec. */
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rc = full_rate_from_perm_spch(&full_rate, perm_spch);
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if (rc < 0)
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return false;
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llist_for_each_entry(trx, &bts->trx_list, list) {
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for (i = 0; i < TRX_NR_TS; i++) {
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pchan = trx->ts[i].pchan_from_config;
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if (pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH)
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rate_match = true;
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else if (full_rate && pchan == GSM_PCHAN_TCH_F)
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rate_match = true;
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else if (full_rate && pchan == GSM_PCHAN_TCH_F_PDCH)
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rate_match = true;
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else if (!full_rate && pchan == GSM_PCHAN_TCH_H)
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rate_match = true;
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}
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}
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if (!rate_match)
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return false;
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/* Check codec support */
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switch (perm_spch) {
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case GSM0808_PERM_FR1:
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/* GSM-FR is always supported by all BTSs. There is also no way to
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* selectively disable GSM-RF per BTS via VTY. */
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return true;
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case GSM0808_PERM_FR2:
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if (bts_codec->efr)
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return true;
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break;
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case GSM0808_PERM_FR3:
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if (bts_codec->amr)
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return true;
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break;
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case GSM0808_PERM_HR1:
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if (bts_codec->hr)
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return true;
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break;
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case GSM0808_PERM_HR3:
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if (bts_codec->amr)
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return true;
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break;
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default:
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return false;
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}
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return false;
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}
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/* Generate the bss supported amr configuration bits (S0-S15) */
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static uint16_t gen_bss_supported_amr_s15_s0(const struct bsc_msc_data *msc, const struct gsm_bts *bts, bool hr)
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{
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const struct gsm48_multi_rate_conf *amr_cfg_bts;
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const struct gsm48_multi_rate_conf *amr_cfg_msc;
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uint16_t amr_s15_s0_bts;
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uint16_t amr_s15_s0_msc;
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/* Lookup the BTS specific AMR rate configuration. This config is set
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* via the VTY for each BTS individually. In cases where no configuration
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* is set we will assume a safe default */
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if (hr) {
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amr_cfg_bts = (struct gsm48_multi_rate_conf *)&bts->mr_half.gsm48_ie;
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amr_s15_s0_bts = gsm0808_sc_cfg_from_gsm48_mr_cfg(amr_cfg_bts, false);
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} else {
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amr_cfg_bts = (struct gsm48_multi_rate_conf *)&bts->mr_full.gsm48_ie;
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amr_s15_s0_bts = gsm0808_sc_cfg_from_gsm48_mr_cfg(amr_cfg_bts, true);
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}
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/* Lookup the AMR rate configuration that is set for the MSC */
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amr_cfg_msc = &msc->amr_conf;
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amr_s15_s0_msc = gsm0808_sc_cfg_from_gsm48_mr_cfg(amr_cfg_msc, true);
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/* Calculate the intersection of the two configurations and update S0-S15
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* in the codec list. */
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return amr_s15_s0_bts & amr_s15_s0_msc;
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}
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/*! Match the codec preferences from local config with a received codec preferences IEs received from the
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* MSC and the BTS' codec configuration.
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* \param[out] chan_mode GSM 04.08 channel mode.
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* \param[out] full_rate true if full-rate.
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* \param[out] s15_s0 codec configuration bits S15-S0 (AMR)
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* \param[in] ct GSM 08.08 channel type received from MSC.
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* \param[in] scl GSM 08.08 speech codec list received from MSC (optional).
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* \param[in] msc associated msc (current codec settings).
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* \param[in] bts associated bts (current codec settings).
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* \returns 0 on success, -1 in case no match was found */
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int match_codec_pref(enum gsm48_chan_mode *chan_mode,
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bool *full_rate,
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uint16_t *s15_s0,
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const struct gsm0808_channel_type *ct,
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const struct gsm0808_speech_codec_list *scl,
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const struct bsc_msc_data *msc,
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const struct gsm_bts *bts)
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{
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unsigned int i;
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uint8_t perm_spch;
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bool match = false;
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const struct gsm0808_speech_codec *sc_match = NULL;
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uint16_t amr_s15_s0_supported;
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int rc;
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/* Note: Normally the MSC should never try to advertise a codec that
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* we did not advertise as supported before. In order to ensure that
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* no unsupported codec is accepted, we make sure that the codec is
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* indeed available with the current BTS and MSC configuration */
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for (i = 0; i < msc->audio_length; i++) {
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/* Pick a permitted speech value from the global codec configuration list */
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perm_spch = audio_support_to_gsm88(msc->audio_support[i]);
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/* Check this permitted speech value against the BTS specific parameters.
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* if the BTS does not support the codec, try the next one */
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if (!test_codec_support_bts(bts, perm_spch))
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continue;
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/* Match the permitted speech value against the codec lists that were
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* advertised by the MS and the MSC */
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if (test_codec_pref(&sc_match, scl, ct, perm_spch)) {
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match = true;
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break;
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}
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}
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/* Exit without result, in case no match can be deteched */
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if (!match) {
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*full_rate = false;
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*chan_mode = GSM48_CMODE_SIGN;
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*s15_s0 = 0;
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return -1;
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}
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/* Determine if the result is a half or full rate codec */
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rc = full_rate_from_perm_spch(full_rate, perm_spch);
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if (rc < 0)
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return -EINVAL;
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/* Lookup a channel mode for the selected codec */
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*chan_mode = gsm88_to_chan_mode(perm_spch);
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/* Special handling for AMR */
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if (perm_spch == GSM0808_PERM_HR3 || perm_spch == GSM0808_PERM_FR3) {
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/* Normally the MSC should never try to advertise an AMR codec
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* configuration that we did not previously advertise as
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* supported. However, to ensure that no unsupported AMR codec
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* configuration enters the further processing steps we again
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* lookup what we support and generate an intersection. All
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* further processing is then done with this intersection
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* result */
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amr_s15_s0_supported = gen_bss_supported_amr_s15_s0(msc, bts, (perm_spch == GSM0808_PERM_HR3));
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if (sc_match)
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*s15_s0 = sc_match->cfg & amr_s15_s0_supported;
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else
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*s15_s0 = amr_s15_s0_supported;
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/* NOTE: The function test_codec_pref() will populate the
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* sc_match pointer from the searched speech codec list. For
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* AoIP based networks, no speech codec list will be present
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* and therefore no sc_match will be populated. For those
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* cases only the local configuration will influence s15_s0.
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* However s15_s0 is always populated with a meaningful value,
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* regardless if AoIP is in use or not. */
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} else
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*s15_s0 = 0;
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return 0;
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}
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/*! Determine the BSS supported speech codec list that is sent to the MSC with
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* the COMPLETE LAYER 3 INFORMATION message.
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* \param[out] scl GSM 08.08 speech codec list with BSS supported codecs.
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* \param[in] msc associated msc (current codec settings).
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* \param[in] bts associated bts (current codec settings). */
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void gen_bss_supported_codec_list(struct gsm0808_speech_codec_list *scl,
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const struct bsc_msc_data *msc, const struct gsm_bts *bts)
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{
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uint8_t perm_spch;
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unsigned int i;
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int rc;
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memset(scl, 0, sizeof(*scl));
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for (i = 0; i < msc->audio_length; i++) {
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/* Pick a permitted speech value from the global codec configuration list */
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perm_spch = audio_support_to_gsm88(msc->audio_support[i]);
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/* Check this permitted speech value against the BTS specific parameters.
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* if the BTS does not support the codec, try the next one */
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if (!test_codec_support_bts(bts, perm_spch))
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continue;
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/* Write item into codec list */
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rc = gsm0808_speech_codec_from_chan_type(&scl->codec[scl->len], perm_spch);
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if (rc != 0)
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continue;
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/* AMR (HR/FR version 3) is the only codec that requires a codec
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* configuration (S0-S15). Determine the current configuration and update
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* the cfg flag. */
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if (msc->audio_support[i]->ver == 3)
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scl->codec[scl->len].cfg = gen_bss_supported_amr_s15_s0(msc, bts, msc->audio_support[i]->hr);
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scl->len++;
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}
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}
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/*! Visit the codec settings for the MSC and for each BTS in order to make sure
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* that the configuration does not contain any combinations that lead into a
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* mutually exclusive codec configuration (empty intersection).
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* \param[in] mscs list head of the msc list.
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* \returns 0 on success, -1 in case an invalid setting is found. */
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int check_codec_pref(struct llist_head *mscs)
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{
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struct bsc_msc_data *msc;
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struct gsm_bts *bts;
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struct gsm0808_speech_codec_list scl;
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int rc = 0;
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llist_for_each_entry(msc, mscs, entry) {
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llist_for_each_entry(bts, &msc->network->bts_list, list) {
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gen_bss_supported_codec_list(&scl, msc, bts);
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if (scl.len <= 0) {
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LOGP(DMSC, LOGL_FATAL,
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"codec-support/trx config of BTS %u does not intersect with codec-list of MSC %u\n",
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bts->nr, msc->nr);
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rc = -1;
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}
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}
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}
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return rc;
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}
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