/* (C) 2011-2020 by Harald Welte * * All Rights Reserved * * 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 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 #include /* properly increment SI2q index and return SI2q data for scheduling */ static inline uint8_t *get_si2q_inc_index(struct gsm_bts *bts) { uint8_t i = bts->si2q_index; /* si2q_count is the max si2q_index value, not the number of messages */ bts->si2q_index = (bts->si2q_index + 1) % (bts->si2q_count + 1); return (uint8_t *)GSM_BTS_SI2Q(bts, i); } /* Apply the rules from 05.02 6.3.1.3 Mapping of BCCH Data */ uint8_t *bts_sysinfo_get(struct gsm_bts *bts, const struct gsm_time *g_time) { unsigned int tc4_cnt = 0; unsigned int tc4_sub[4]; /* System information type 2 bis or 2 ter messages are sent if * needed, as determined by the system operator. If only one of * them is needed, it is sent when TC = 5. If both are needed, * 2bis is sent when TC = 5 and 2ter is sent at least once * within any of 4 consecutive occurrences of TC = 4. */ /* System information type 2 quater is sent if needed, as * determined by the system operator. If sent on BCCH Norm, it * shall be sent when TC = 5 if neither of 2bis and 2ter are * used, otherwise it shall be sent at least once within any of * 4 consecutive occurrences of TC = 4. If sent on BCCH Ext, it * is sent at least once within any of 4 consecutive occurrences * of TC = 5. */ /* System Information type 9 is sent in those blocks with * TC = 4 which are specified in system information type 3 as * defined in 3GPP TS 04.08. */ /* System Information Type 13 need only be sent if GPRS support * is indicated in one or more of System Information Type 3 or 4 * or 7 or 8 messages. These messages also indicate if the * message is sent on the BCCH Norm or if the message is * transmitted on the BCCH Ext. In the case that the message is * sent on the BCCH Norm, it is sent at least once within any of * 4 consecutive occurrences of TC = 4. */ /* We only implement BCCH Norm at this time */ switch (g_time->tc) { case 0: /* System Information Type 1 need only be sent if * frequency hopping is in use or when the NCH is * present in a cell. If the MS finds another message * when TC = 0, it can assume that System Information * Type 1 is not in use. */ if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_1)) return GSM_BTS_SI(bts, SYSINFO_TYPE_1); return GSM_BTS_SI(bts, SYSINFO_TYPE_2); case 1: /* A SI 2 message will be sent at least every time TC = 1. */ return GSM_BTS_SI(bts, SYSINFO_TYPE_2); case 2: return GSM_BTS_SI(bts, SYSINFO_TYPE_3); case 3: return GSM_BTS_SI(bts, SYSINFO_TYPE_4); case 4: /* iterate over 2ter, 2quater, 9, 13 */ /* determine how many SI we need to send on TC=4, * and which of them we send when */ if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) && GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis)) { tc4_sub[tc4_cnt] = SYSINFO_TYPE_2ter; tc4_cnt += 1; } if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) && (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) || GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))) { tc4_sub[tc4_cnt] = SYSINFO_TYPE_2quater; tc4_cnt += 1; } if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_13) && pcu_connected()) { tc4_sub[tc4_cnt] = SYSINFO_TYPE_13; tc4_cnt += 1; } if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_9)) { /* FIXME: check SI3 scheduling info! */ tc4_sub[tc4_cnt] = SYSINFO_TYPE_9; tc4_cnt += 1; } /* simply send SI2 if we have nothing else to send */ if (tc4_cnt == 0) return GSM_BTS_SI(bts, SYSINFO_TYPE_2); else { /* increment static counter by one, modulo count */ bts->si.tc4_ctr = (bts->si.tc4_ctr + 1) % tc4_cnt; if (tc4_sub[bts->si.tc4_ctr] == SYSINFO_TYPE_2quater) return get_si2q_inc_index(bts); return GSM_BTS_SI(bts, tc4_sub[bts->si.tc4_ctr]); } case 5: /* 2bis, 2ter, 2quater */ if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter)) return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis); else if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis)) return GSM_BTS_SI(bts, SYSINFO_TYPE_2ter); else if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) && GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter)) return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis); else if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter)) return get_si2q_inc_index(bts); /* simply send SI2 if we have nothing else to send */ else return GSM_BTS_SI(bts, SYSINFO_TYPE_2); break; case 6: return GSM_BTS_SI(bts, SYSINFO_TYPE_3); case 7: return GSM_BTS_SI(bts, SYSINFO_TYPE_4); } /* this should never bve reached. We must transmit a BCCH * message on the normal BCCH in all cases. */ OSMO_ASSERT(0); return 0; } uint8_t num_agch(const struct gsm_bts_trx *trx, const char * arg) { const struct gsm_bts *b = trx->bts; const struct gsm48_system_information_type_3 *si3; if (GSM_BTS_HAS_SI(b, SYSINFO_TYPE_3)) { si3 = GSM_BTS_SI(b, SYSINFO_TYPE_3); return si3->control_channel_desc.bs_ag_blks_res; } LOGP(DL1P, LOGL_NOTICE, "%s: Unable to determine actual BS_AG_BLKS_RES " "value as SI3 is not available yet, fallback to 1\n", arg); return 1; } /* obtain the next to-be transmitted dowlink SACCH frame (L2 hdr + L3); returns pointer to lchan->si buffer */ uint8_t *lchan_sacch_get(struct gsm_lchan *lchan) { uint32_t tmp, i; for (i = 0; i < _MAX_SYSINFO_TYPE; i++) { tmp = (lchan->si.last + 1 + i) % _MAX_SYSINFO_TYPE; if (!(lchan->si.valid & (1 << tmp))) continue; lchan->si.last = tmp; return GSM_LCHAN_SI(lchan, tmp); } LOGPLCHAN(lchan, DL1P, LOGL_NOTICE, "SACCH no SI available\n"); return NULL; } /* re-generate SI3 restoctets with GPRS indicator depending on the PCU socket connection state */ void regenerate_si3_restoctets(struct gsm_bts *bts) { uint8_t *si3_buf = GSM_BTS_SI(bts, SYSINFO_TYPE_3); size_t si3_size = offsetof(struct gsm48_system_information_type_3, rest_octets); struct osmo_gsm48_si_ro_info si3ro_tmp; /* If BSC has never set SI3, there's nothing to patch */ if (!GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_3)) return; /* If SI3 from BSC doesn't have a GPRS indicator, we won't have anything to patch */ if (!bts->si3_ro_decoded.gprs_ind.present) return; /* Create a temporary copy and patch that, if no PCU is around */ si3ro_tmp = bts->si3_ro_decoded; if (!pcu_connected()) { if (!bts->si_gprs_ind_disabled) LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI (No PCU connected)\n"); bts->si_gprs_ind_disabled = true; si3ro_tmp.gprs_ind.present = 0; } else { if (bts->si_gprs_ind_disabled) LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI (PCU connected)\n"); bts->si_gprs_ind_disabled = false; si3ro_tmp.gprs_ind.present = 1; /* is a no-op as we copy from bts->si3_ro_decoded */ } /* re-generate the binary SI3 rest octets */ osmo_gsm48_rest_octets_si3_encode(si3_buf + si3_size, &si3ro_tmp); } /* get the offset of the SI4 rest octets */ int get_si4_ro_offset(const uint8_t *si4_buf) { const struct gsm48_system_information_type_4 *si4 = (const struct gsm48_system_information_type_4 *) si4_buf; int si4_size; /* start with the length of the mandatory part */ si4_size = offsetof(struct gsm48_system_information_type_4, data); /* then add optional parts, if any */ if (si4->data[0] == GSM48_IE_CBCH_CHAN_DESC) { /* fixed 4-byte TV IE, see Table 9.1.36.1 of TS 44.018 */ si4_size += 4; if (si4->data[4] == GSM48_IE_CBCH_MOB_AL) si4_size += TLV_GROSS_LEN(si4->data[5]); } if (si4_size >= GSM_MACBLOCK_LEN) return -EINVAL; return si4_size; } /* re-generate SI4 restoctets with GPRS indicator depending on the PCU socket connection state */ void regenerate_si4_restoctets(struct gsm_bts *bts) { uint8_t *si4_buf = GSM_BTS_SI(bts, SYSINFO_TYPE_4); struct osmo_gsm48_si_ro_info si4ro_tmp; int si4_size; /* If BSC has never set SI4, there's nothing to patch */ if (!GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_4)) return; /* If SI4 from BSC doesn't have a GPRS indicator, we won't have anything to patch */ if (!bts->si4_ro_decoded.gprs_ind.present) return; si4_size = get_si4_ro_offset(si4_buf); if (si4_size < 0) { LOGP(DPCU, LOGL_ERROR, "Cannot parse SI4, hence not patching GPRS indicator\n"); return; } /* Create a temporary copy and patch that, if no PCU is around */ si4ro_tmp = bts->si4_ro_decoded; if (!pcu_connected()) { if (!bts->si_gprs_ind_disabled) LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI (No PCU connected)\n"); bts->si_gprs_ind_disabled = true; si4ro_tmp.gprs_ind.present = 0; } else { if (bts->si_gprs_ind_disabled) LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI (PCU connected)\n"); bts->si_gprs_ind_disabled = false; si4ro_tmp.gprs_ind.present = 1; /* is a no-op as we copy from bts->si4_ro_decoded */ } /* re-generate the binary SI4 rest octets */ osmo_gsm48_rest_octets_si4_encode(si4_buf + si4_size, &si4ro_tmp, GSM_MACBLOCK_LEN - si4_size); }