146 lines
5.0 KiB
C
146 lines
5.0 KiB
C
/* (C) 2011 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 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 <osmocom/gsm/gsm_utils.h>
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#include <osmocom/gsm/sysinfo.h>
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#include <osmo-bts/gsm_data.h>
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#define BTS_HAS_SI(bts, sinum) ((bts)->si_valid & (1 << sinum))
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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, struct gsm_time *g_time)
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{
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struct gsm_bts_role_bts *btsb = bts_role_bts(bts);
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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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return GSM_BTS_SI(bts, SYSINFO_TYPE_1);
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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 (BTS_HAS_SI(bts, SYSINFO_TYPE_2ter)) {
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tc4_sub[tc4_cnt] = SYSINFO_TYPE_2ter;
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tc4_cnt += 1; /* 2bis */
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}
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if (BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
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(BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) ||
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BTS_HAS_SI(bts, SYSINFO_TYPE_2bis))) {
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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 (BTS_HAS_SI(bts, SYSINFO_TYPE_13)) {
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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 (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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btsb->si.tc4_ctr = (btsb->si.tc4_ctr + 1) % tc4_cnt;
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return GSM_BTS_SI(bts, tc4_sub[btsb->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 (BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
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!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 (BTS_HAS_SI(bts, SYSINFO_TYPE_2ter) &&
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!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 (BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
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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 (BTS_HAS_SI(bts, SYSINFO_TYPE_2quater) &&
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!BTS_HAS_SI(bts, SYSINFO_TYPE_2bis) &&
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!BTS_HAS_SI(bts, SYSINFO_TYPE_2ter))
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return GSM_BTS_SI(bts, SYSINFO_TYPE_2quater);
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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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return NULL;
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}
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uint8_t *lchan_sacch_get(struct gsm_lchan *lchan, struct gsm_time *g_time)
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{
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uint32_t tmp;
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for (tmp = lchan->si.last + 1; tmp != lchan->si.last; tmp = (tmp + 1) % 32) {
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if (lchan->si.valid & (1 << tmp)) {
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lchan->si.last = tmp;
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return lchan->si.buf[tmp];
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}
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}
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return NULL;
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}
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