281 lines
9.9 KiB
C
281 lines
9.9 KiB
C
/* (C) 2011-2020 by Harald Welte <laforge@gnumonks.org>
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*
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* All Rights Reserved
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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 <stdint.h>
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#include <errno.h>
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#include <osmocom/gsm/gsm_utils.h>
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#include <osmocom/gsm/sysinfo.h>
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#include <osmo-bts/logging.h>
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#include <osmo-bts/gsm_data.h>
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#include <osmo-bts/pcu_if.h>
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#include <osmo-bts/bts.h>
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#include <osmo-bts/bts_trx.h>
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/* properly increment SI2q index and return SI2q data for scheduling */
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static inline uint8_t *get_si2q_inc_index(struct gsm_bts *bts)
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{
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uint8_t i = bts->si2q_index;
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/* si2q_count is the max si2q_index value, not the number of messages */
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bts->si2q_index = (bts->si2q_index + 1) % (bts->si2q_count + 1);
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return (uint8_t *)GSM_BTS_SI2Q(bts, i);
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}
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/* Apply the rules from 05.02 6.3.1.3 Mapping of BCCH Data */
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uint8_t *bts_sysinfo_get(struct gsm_bts *bts, const struct gsm_time *g_time)
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{
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unsigned int tc4_cnt = 0;
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unsigned int tc4_sub[4];
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/* System information type 2 bis or 2 ter messages are sent if
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* needed, as determined by the system operator. If only one of
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* them is needed, it is sent when TC = 5. If both are needed,
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* 2bis is sent when TC = 5 and 2ter is sent at least once
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* within any of 4 consecutive occurrences of TC = 4. */
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/* System information type 2 quater is sent if needed, as
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* determined by the system operator. If sent on BCCH Norm, it
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* shall be sent when TC = 5 if neither of 2bis and 2ter are
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* used, otherwise it shall be sent at least once within any of
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* 4 consecutive occurrences of TC = 4. If sent on BCCH Ext, it
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* is sent at least once within any of 4 consecutive occurrences
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* of TC = 5. */
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/* System Information type 9 is sent in those blocks with
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* TC = 4 which are specified in system information type 3 as
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* defined in 3GPP TS 04.08. */
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/* System Information Type 13 need only be sent if GPRS support
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* is indicated in one or more of System Information Type 3 or 4
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* or 7 or 8 messages. These messages also indicate if the
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* message is sent on the BCCH Norm or if the message is
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* transmitted on the BCCH Ext. In the case that the message is
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* sent on the BCCH Norm, it is sent at least once within any of
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* 4 consecutive occurrences of TC = 4. */
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/* We only implement BCCH Norm at this time */
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switch (g_time->tc) {
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case 0:
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/* System Information Type 1 need only be sent if
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* frequency hopping is in use or when the NCH is
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* present in a cell. If the MS finds another message
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* when TC = 0, it can assume that System Information
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* Type 1 is not in use. */
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if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_1))
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return GSM_BTS_SI(bts, SYSINFO_TYPE_1);
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2);
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case 1:
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/* A SI 2 message will be sent at least every time TC = 1. */
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2);
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case 2:
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return GSM_BTS_SI(bts, SYSINFO_TYPE_3);
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case 3:
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return GSM_BTS_SI(bts, SYSINFO_TYPE_4);
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case 4:
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/* iterate over 2ter, 2quater, 9, 13 */
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/* determine how many SI we need to send on TC=4,
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* and which of them we send when */
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if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) && GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis)) {
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tc4_sub[tc4_cnt] = SYSINFO_TYPE_2ter;
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tc4_cnt += 1;
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}
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if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
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(GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) || GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))) {
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tc4_sub[tc4_cnt] = SYSINFO_TYPE_2quater;
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tc4_cnt += 1;
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}
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if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_13) && pcu_connected()) {
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tc4_sub[tc4_cnt] = SYSINFO_TYPE_13;
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tc4_cnt += 1;
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}
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if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_9)) {
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/* FIXME: check SI3 scheduling info! */
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tc4_sub[tc4_cnt] = SYSINFO_TYPE_9;
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tc4_cnt += 1;
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}
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/* simply send SI2 if we have nothing else to send */
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if (tc4_cnt == 0)
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2);
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else {
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/* increment static counter by one, modulo count */
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bts->si.tc4_ctr = (bts->si.tc4_ctr + 1) % tc4_cnt;
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if (tc4_sub[bts->si.tc4_ctr] == SYSINFO_TYPE_2quater)
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return get_si2q_inc_index(bts);
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return GSM_BTS_SI(bts, tc4_sub[bts->si.tc4_ctr]);
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}
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case 5:
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/* 2bis, 2ter, 2quater */
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if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis);
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else if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis))
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2ter);
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else if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) && GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2bis);
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else if (GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
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!GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) && !GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
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return get_si2q_inc_index(bts);
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/* simply send SI2 if we have nothing else to send */
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else
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2);
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break;
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case 6:
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return GSM_BTS_SI(bts, SYSINFO_TYPE_3);
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case 7:
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return GSM_BTS_SI(bts, SYSINFO_TYPE_4);
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}
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/* this should never bve reached. We must transmit a BCCH
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* message on the normal BCCH in all cases. */
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OSMO_ASSERT(0);
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return 0;
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}
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uint8_t num_agch(const struct gsm_bts_trx *trx, const char * arg)
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{
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const struct gsm_bts *b = trx->bts;
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const struct gsm48_system_information_type_3 *si3;
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if (GSM_BTS_HAS_SI(b, SYSINFO_TYPE_3)) {
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si3 = GSM_BTS_SI(b, SYSINFO_TYPE_3);
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return si3->control_channel_desc.bs_ag_blks_res;
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}
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LOGP(DL1P, LOGL_NOTICE, "%s: Unable to determine actual BS_AG_BLKS_RES "
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"value as SI3 is not available yet, fallback to 1\n", arg);
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return 1;
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}
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/* Returns position of the NCH accroding to SI1 rest octets. See Table 10.5.2.32.1 of TS 44.018.
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* Returns < 0, if not present. */
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int pos_nch(const struct gsm_bts_trx *trx, const char *arg)
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{
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const struct gsm_bts *b = trx->bts;
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const struct gsm48_system_information_type_1 *si1;
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if (GSM_BTS_HAS_SI(b, SYSINFO_TYPE_1)) {
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si1 = GSM_BTS_SI(b, SYSINFO_TYPE_1);
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if (si1->rest_octets[0] & 0x80) {
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/* H <NCH Position : bit (5)> */
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return (si1->rest_octets[0] >> 2) & 0x1f;
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}
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return -ENOTSUP;
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}
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LOGP(DL1P, LOGL_NOTICE, "%s: Unable to determine actual NCH Position "
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"value as SI1 is not available yet.\n", arg);
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return -EINVAL;
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}
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/* re-generate SI3 restoctets with GPRS indicator depending on the PCU socket connection state */
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void regenerate_si3_restoctets(struct gsm_bts *bts)
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{
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uint8_t *si3_buf = GSM_BTS_SI(bts, SYSINFO_TYPE_3);
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size_t si3_size = offsetof(struct gsm48_system_information_type_3, rest_octets);
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struct osmo_gsm48_si_ro_info si3ro_tmp;
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/* If BSC has never set SI3, there's nothing to patch */
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if (!GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_3))
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return;
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/* If SI3 from BSC doesn't have a GPRS indicator, we won't have anything to patch */
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if (!bts->si3_ro_decoded.gprs_ind.present)
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return;
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/* Create a temporary copy and patch that, if no PCU is around */
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si3ro_tmp = bts->si3_ro_decoded;
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if (!pcu_connected()) {
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if (!bts->si_gprs_ind_disabled)
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LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI (No PCU connected)\n");
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bts->si_gprs_ind_disabled = true;
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si3ro_tmp.gprs_ind.present = 0;
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} else {
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if (bts->si_gprs_ind_disabled)
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LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI (PCU connected)\n");
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bts->si_gprs_ind_disabled = false;
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si3ro_tmp.gprs_ind.present = 1; /* is a no-op as we copy from bts->si3_ro_decoded */
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}
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/* re-generate the binary SI3 rest octets */
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osmo_gsm48_rest_octets_si3_encode(si3_buf + si3_size, &si3ro_tmp);
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}
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/* get the offset of the SI4 rest octets */
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int get_si4_ro_offset(const uint8_t *si4_buf)
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{
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const struct gsm48_system_information_type_4 *si4 =
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(const struct gsm48_system_information_type_4 *) si4_buf;
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int si4_size;
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/* start with the length of the mandatory part */
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si4_size = offsetof(struct gsm48_system_information_type_4, data);
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/* then add optional parts, if any */
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if (si4->data[0] == GSM48_IE_CBCH_CHAN_DESC) {
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/* fixed 4-byte TV IE, see Table 9.1.36.1 of TS 44.018 */
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si4_size += 4;
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if (si4->data[4] == GSM48_IE_CBCH_MOB_AL)
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si4_size += TLV_GROSS_LEN(si4->data[5]);
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}
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if (si4_size >= GSM_MACBLOCK_LEN)
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return -EINVAL;
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return si4_size;
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}
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/* re-generate SI4 restoctets with GPRS indicator depending on the PCU socket connection state */
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void regenerate_si4_restoctets(struct gsm_bts *bts)
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{
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uint8_t *si4_buf = GSM_BTS_SI(bts, SYSINFO_TYPE_4);
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struct osmo_gsm48_si_ro_info si4ro_tmp;
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int si4_size;
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/* If BSC has never set SI4, there's nothing to patch */
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if (!GSM_BTS_HAS_SI(bts, SYSINFO_TYPE_4))
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return;
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/* If SI4 from BSC doesn't have a GPRS indicator, we won't have anything to patch */
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if (!bts->si4_ro_decoded.gprs_ind.present)
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return;
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si4_size = get_si4_ro_offset(si4_buf);
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if (si4_size < 0) {
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LOGP(DPCU, LOGL_ERROR, "Cannot parse SI4, hence not patching GPRS indicator\n");
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return;
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}
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/* Create a temporary copy and patch that, if no PCU is around */
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si4ro_tmp = bts->si4_ro_decoded;
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if (!pcu_connected()) {
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if (!bts->si_gprs_ind_disabled)
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LOGP(DPCU, LOGL_NOTICE, "Disabling GPRS Indicator in SI (No PCU connected)\n");
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bts->si_gprs_ind_disabled = true;
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si4ro_tmp.gprs_ind.present = 0;
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} else {
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if (bts->si_gprs_ind_disabled)
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LOGP(DPCU, LOGL_NOTICE, "Enabling GPRS Indicator in SI (PCU connected)\n");
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bts->si_gprs_ind_disabled = false;
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si4ro_tmp.gprs_ind.present = 1; /* is a no-op as we copy from bts->si4_ro_decoded */
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}
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/* re-generate the binary SI4 rest octets */
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osmo_gsm48_rest_octets_si4_encode(si4_buf + si4_size, &si4ro_tmp, GSM_MACBLOCK_LEN - si4_size);
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}
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