/* * (C) 2017-2018 by sysmocom s.f.m.c. GmbH * All Rights Reserved * * Author: Philipp Maier * * 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 . * */ #include #include #include #include #include #include #include #include /* Determine whether a permitted speech value is specifies a half rate or full * rate codec */ static int full_rate_from_perm_spch(bool * full_rate, enum gsm0808_permitted_speech perm_spch) { /* Check if the result is a half or full rate codec */ switch (perm_spch) { case GSM0808_PERM_HR1: case GSM0808_PERM_HR2: case GSM0808_PERM_HR3: case GSM0808_PERM_HR4: case GSM0808_PERM_HR6: *full_rate = false; break; case GSM0808_PERM_FR1: case GSM0808_PERM_FR2: case GSM0808_PERM_FR3: case GSM0808_PERM_FR4: case GSM0808_PERM_FR5: *full_rate = true; break; default: LOGP(DMSC, LOGL_ERROR, "Invalid permitted-speech value: %u\n", perm_spch); return -EINVAL; } return 0; } /* Helper function for match_codec_pref(), looks up a matching chan mode for * a given permitted speech value */ static enum gsm48_chan_mode gsm88_to_chan_mode(enum gsm0808_permitted_speech speech) { switch (speech) { case GSM0808_PERM_HR1: case GSM0808_PERM_FR1: return GSM48_CMODE_SPEECH_V1; break; case GSM0808_PERM_FR2: return GSM48_CMODE_SPEECH_EFR; break; case GSM0808_PERM_HR3: case GSM0808_PERM_FR3: return GSM48_CMODE_SPEECH_AMR; break; case GSM0808_PERM_HR2: LOGP(DMSC, LOGL_FATAL, "Speech HR2 was never specified!\n"); /* fall through */ default: LOGP(DMSC, LOGL_FATAL, "Unsupported permitted speech %s selected, " "assuming AMR as channel mode...\n", gsm0808_permitted_speech_name(speech)); return GSM48_CMODE_SPEECH_AMR; } } /* Helper function for match_codec_pref(), looks up a matching permitted speech * value for a given msc audio codec pref */ static enum gsm0808_permitted_speech audio_support_to_gsm88(const struct gsm_audio_support *audio) { if (audio->hr) { switch (audio->ver) { case 1: return GSM0808_PERM_HR1; break; case 2: return GSM0808_PERM_HR2; break; case 3: return GSM0808_PERM_HR3; break; default: LOGP(DMSC, LOGL_ERROR, "Wrong speech mode: hr%d, using hr1 instead\n", audio->ver); return GSM0808_PERM_HR1; } } else { switch (audio->ver) { case 1: return GSM0808_PERM_FR1; break; case 2: return GSM0808_PERM_FR2; break; case 3: return GSM0808_PERM_FR3; break; default: LOGP(DMSC, LOGL_ERROR, "Wrong speech mode: fr%d, using fr1 instead\n", audio->ver); return GSM0808_PERM_FR1; } } } /* Helper function for match_codec_pref(), tests if a given audio support * matches one of the permitted speech settings of the channel type element. * The matched permitted speech value is then also compared against the * speech codec list. (optional, only relevant for AoIP) */ static bool test_codec_pref(const struct gsm0808_speech_codec **sc_match, const struct gsm0808_speech_codec_list *scl, const struct gsm0808_channel_type *ct, uint8_t perm_spch) { unsigned int i; bool match = false; struct gsm0808_speech_codec sc; int rc; *sc_match = NULL; /* Try to find the given permitted speech value in the * codec list of the channel type element */ for (i = 0; i < ct->perm_spch_len; i++) { if (ct->perm_spch[i] == perm_spch) { match = true; break; } } /* If we do not have a speech codec list to test against, * we just exit early (will be always the case in non-AoIP networks) */ if (!scl || !scl->len) return match; /* If we failed to match until here, there is no * point in testing further */ if (match == false) return false; /* Extrapolate speech codec data */ rc = gsm0808_speech_codec_from_chan_type(&sc, perm_spch); if (rc < 0) return false; /* Try to find extrapolated speech codec data in * the speech codec list */ for (i = 0; i < scl->len; i++) { if (sc.type == scl->codec[i].type) { *sc_match = &scl->codec[i]; return true; } } return false; } /* Helper function to check if the given permitted speech value is supported * by the BTS. (vty option bts->codec-support). */ static bool test_codec_support_bts(const struct gsm_bts *bts, uint8_t perm_spch) { struct gsm_bts_trx *trx; const struct bts_codec_conf *bts_codec = &bts->codec; unsigned int i; bool full_rate; int rc; enum gsm_phys_chan_config pchan; bool rate_match = false; /* Check if the BTS provides a physical channel that matches the * bandwith of the desired codec. */ rc = full_rate_from_perm_spch(&full_rate, perm_spch); if (rc < 0) return false; llist_for_each_entry(trx, &bts->trx_list, list) { for (i = 0; i < TRX_NR_TS; i++) { pchan = trx->ts[i].pchan_from_config; if (pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH) rate_match = true; else if (full_rate && pchan == GSM_PCHAN_TCH_F) rate_match = true; else if (full_rate && pchan == GSM_PCHAN_TCH_F_PDCH) rate_match = true; else if (!full_rate && pchan == GSM_PCHAN_TCH_H) rate_match = true; } } if (!rate_match) return false; /* Check codec support */ switch (perm_spch) { case GSM0808_PERM_FR1: /* GSM-FR is always supported by all BTSs. There is also no way to * selectively disable GSM-RF per BTS via VTY. */ return true; case GSM0808_PERM_FR2: if (bts_codec->efr) return true; break; case GSM0808_PERM_FR3: if (bts_codec->amr) return true; break; case GSM0808_PERM_HR1: if (bts_codec->hr) return true; break; case GSM0808_PERM_HR3: if (bts_codec->amr) return true; break; default: return false; } return false; } /* Generate the bss supported amr configuration bits (S0-S15) */ static uint16_t gen_bss_supported_amr_s15_s0(const struct bsc_msc_data *msc, const struct gsm_bts *bts, bool hr) { const struct gsm48_multi_rate_conf *amr_cfg_bts; const struct gsm48_multi_rate_conf *amr_cfg_msc; uint16_t amr_s15_s0_bts; uint16_t amr_s15_s0_msc; /* Lookup the BTS specific AMR rate configuration. This config is set * via the VTY for each BTS individually. In cases where no configuration * is set we will assume a safe default */ if (hr) { amr_cfg_bts = (struct gsm48_multi_rate_conf *)&bts->mr_half.gsm48_ie; amr_s15_s0_bts = gsm0808_sc_cfg_from_gsm48_mr_cfg(amr_cfg_bts, false); } else { amr_cfg_bts = (struct gsm48_multi_rate_conf *)&bts->mr_full.gsm48_ie; amr_s15_s0_bts = gsm0808_sc_cfg_from_gsm48_mr_cfg(amr_cfg_bts, true); } /* Lookup the AMR rate configuration that is set for the MSC */ amr_cfg_msc = &msc->amr_conf; amr_s15_s0_msc = gsm0808_sc_cfg_from_gsm48_mr_cfg(amr_cfg_msc, true); /* Calculate the intersection of the two configurations and update S0-S15 * in the codec list. */ return amr_s15_s0_bts & amr_s15_s0_msc; } /* Special handling for AMR rate configuration bits (S15-S0) */ static int match_amr_s15_s0(struct channel_mode_and_rate *ch_mode_rate, const struct bsc_msc_data *msc, const struct gsm_bts *bts, const struct gsm0808_speech_codec *sc_match, uint8_t perm_spch) { uint16_t amr_s15_s0_supported; /* Normally the MSC should never try to advertise an AMR codec * configuration that we did not previously advertised as supported. * However, to ensure that no unsupported AMR codec configuration * enters the further processing steps we again lookup what we support * and generate an intersection. All further processing is then done * with this intersection result. At the same time we will make sure * that the intersection contains at least one rate setting. */ amr_s15_s0_supported = gen_bss_supported_amr_s15_s0(msc, bts, (perm_spch == GSM0808_PERM_HR3)); /* NOTE: The sc_match pointer points to a speech codec from the speech * codec list that has been communicated with the ASSIGNMENT COMMAND. * However, only AoIP based networks will include a speech codec list * into the ASSIGNMENT COMMAND. For non AoIP based networks, no speech * codec (sc_match) will be available, so we will fully rely on the * local configuration for thoses cases. */ if (sc_match) ch_mode_rate->s15_s0 = sc_match->cfg & amr_s15_s0_supported; else ch_mode_rate->s15_s0 = amr_s15_s0_supported; /* Prefer "Config-NB-Code = 1" (S1) over all other AMR rates setttings. * When S1 is set, the active set will automatically include 12.2k, 7.4k, * 5.9k, 4.75k, in case of HR 12,2k is left out. */ if (ch_mode_rate->s15_s0 & GSM0808_SC_CFG_AMR_4_75_5_90_7_40_12_20) { ch_mode_rate->s15_s0 &= 0xff00; ch_mode_rate->s15_s0 |= GSM0808_SC_CFG_AMR_4_75_5_90_7_40_12_20; } /* Make sure at least one rate is set. */ if ((ch_mode_rate->s15_s0 & 0x00ff) == 0x0000) return -EINVAL; return 0; } /*! Match the codec preferences from local config with a received codec preferences IEs received from the * MSC and the BTS' codec configuration. * \param[out] ch_mode_rate resulting codec and rate information * \param[in] ct GSM 08.08 channel type received from MSC. * \param[in] scl GSM 08.08 speech codec list received from MSC (optional). * \param[in] msc associated msc (current codec settings). * \param[in] bts associated bts (current codec settings). * \param[in] pref selected rate preference (full, half or none). * \returns 0 on success, -1 in case no match was found */ int match_codec_pref(struct channel_mode_and_rate *ch_mode_rate, const struct gsm0808_channel_type *ct, const struct gsm0808_speech_codec_list *scl, const struct bsc_msc_data *msc, const struct gsm_bts *bts, enum rate_pref rate_pref) { unsigned int i; uint8_t perm_spch; bool full_rate; bool match = false; const struct gsm0808_speech_codec *sc_match = NULL; int rc; /* Note: Normally the MSC should never try to advertise a codec that * we did not advertise as supported before. In order to ensure that * no unsupported codec is accepted, we make sure that the codec is * indeed available with the current BTS and MSC configuration */ for (i = 0; i < msc->audio_length; i++) { /* Pick a permitted speech value from the global codec configuration list */ perm_spch = audio_support_to_gsm88(msc->audio_support[i]); /* Determine if the result is a half or full rate codec */ rc = full_rate_from_perm_spch(&full_rate, perm_spch); if (rc < 0) return -EINVAL; ch_mode_rate->chan_rate = full_rate ? CH_RATE_FULL : CH_RATE_HALF; /* If we have a preference for FR or HR in our request, we * discard the potential match */ if (rate_pref == RATE_PREF_HR && ch_mode_rate->chan_rate == CH_RATE_FULL) continue; if (rate_pref == RATE_PREF_FR && ch_mode_rate->chan_rate == CH_RATE_HALF) continue; /* Check this permitted speech value against the BTS specific parameters. * if the BTS does not support the codec, try the next one */ if (!test_codec_support_bts(bts, perm_spch)) continue; /* Match the permitted speech value against the codec lists that were * advertised by the MS and the MSC */ if (!test_codec_pref(&sc_match, scl, ct, perm_spch)) { continue; } /* Special handling for AMR */ if (perm_spch == GSM0808_PERM_HR3 || perm_spch == GSM0808_PERM_FR3) { rc = match_amr_s15_s0(ch_mode_rate, msc, bts, sc_match, perm_spch); if (rc < 0) { ch_mode_rate->s15_s0 = 0; continue; } } else ch_mode_rate->s15_s0 = 0; match = true; break; } /* Exit without result, in case no match can be deteched */ if (!match) { ch_mode_rate->chan_mode = GSM48_CMODE_SIGN; ch_mode_rate->chan_rate = CH_RATE_SDCCH; ch_mode_rate->s15_s0 = 0; return -1; } /* Lookup a channel mode for the selected codec */ ch_mode_rate->chan_mode = gsm88_to_chan_mode(perm_spch); return 0; } /*! Determine the BSS supported speech codec list that is sent to the MSC with * the COMPLETE LAYER 3 INFORMATION message. * \param[out] scl GSM 08.08 speech codec list with BSS supported codecs. * \param[in] msc associated msc (current codec settings). * \param[in] bts associated bts (current codec settings). */ void gen_bss_supported_codec_list(struct gsm0808_speech_codec_list *scl, const struct bsc_msc_data *msc, const struct gsm_bts *bts) { uint8_t perm_spch; unsigned int i; int rc; memset(scl, 0, sizeof(*scl)); for (i = 0; i < msc->audio_length; i++) { /* Pick a permitted speech value from the global codec configuration list */ perm_spch = audio_support_to_gsm88(msc->audio_support[i]); /* Check this permitted speech value against the BTS specific parameters. * if the BTS does not support the codec, try the next one */ if (!test_codec_support_bts(bts, perm_spch)) continue; /* Write item into codec list */ rc = gsm0808_speech_codec_from_chan_type(&scl->codec[scl->len], perm_spch); if (rc != 0) continue; /* AMR (HR/FR version 3) is the only codec that requires a codec * configuration (S0-S15). Determine the current configuration and update * the cfg flag. */ if (msc->audio_support[i]->ver == 3) scl->codec[scl->len].cfg = gen_bss_supported_amr_s15_s0(msc, bts, msc->audio_support[i]->hr); scl->len++; } } /*! Calculate the intersection of the rate configuration of two multirate configuration * IE structures. The result c will be a copy of a, but the rate configuration bits * will be the intersection of the rate configuration bits in a and b. * \param[out] c user provided memory to store the result. * \param[in] a multi rate configuration a. * \param[in] b multi rate configuration b. * \returns 0 on success, -1 when the result contains an empty set of modes. */ int calc_amr_rate_intersection(struct gsm48_multi_rate_conf *c, const struct gsm48_multi_rate_conf *b, const struct gsm48_multi_rate_conf *a) { struct gsm48_multi_rate_conf res; uint8_t *_a = (uint8_t *) a; uint8_t *_b = (uint8_t *) b; uint8_t *_res = (uint8_t *) & res; memcpy(&res, a, sizeof(res)); _res[1] = _a[1] & _b[1]; if (_res[1] == 0x00) return -1; if (c) memcpy(c, &res, sizeof(*c)); return 0; } /*! Visit the codec settings for the MSC and for each BTS in order to make sure * that the configuration does not contain any combinations that lead into a * mutually exclusive codec configuration (empty intersection). * \param[in] mscs list head of the msc list. * \returns 0 on success, -1 in case an invalid setting is found. */ int check_codec_pref(struct llist_head *mscs) { struct bsc_msc_data *msc; struct gsm_bts *bts; struct gsm0808_speech_codec_list scl; int rc = 0; int rc_rate; const struct gsm48_multi_rate_conf *bts_gsm48_ie; llist_for_each_entry(msc, mscs, entry) { llist_for_each_entry(bts, &msc->network->bts_list, list) { gen_bss_supported_codec_list(&scl, msc, bts); if (scl.len <= 0) { LOGP(DMSC, LOGL_FATAL, "codec-support/trx config of BTS %u does not intersect with codec-list of MSC %u\n", bts->nr, msc->nr); rc = -1; } bts_gsm48_ie = (struct gsm48_multi_rate_conf *)&bts->mr_full.gsm48_ie; rc_rate = calc_amr_rate_intersection(NULL, &msc->amr_conf, bts_gsm48_ie); if (rc_rate < 0) { LOGP(DMSC, LOGL_FATAL, "network amr tch-f mode config of BTS %u does not intersect with amr-config of MSC %u\n", bts->nr, msc->nr); rc = -1; } bts_gsm48_ie = (struct gsm48_multi_rate_conf *)&bts->mr_half.gsm48_ie; rc_rate = calc_amr_rate_intersection(NULL, &msc->amr_conf, bts_gsm48_ie); if (rc_rate < 0) { LOGP(DMSC, LOGL_FATAL, "network amr tch-h mode config of BTS %u does not intersect with amr-config of MSC %u\n", bts->nr, msc->nr); rc = -1; } } } return rc; }