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osmo-msc/openbsc/src/system_information.c

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/* GSM 04.08 System Information (SI) encoding and decoding
* 3GPP TS 04.08 version 7.21.0 Release 1998 / ETSI TS 100 940 V7.21.0 */
/* (C) 2008-2009 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <openbsc/gsm_04_08.h>
#include <openbsc/gsm_data.h>
#include <openbsc/abis_rsl.h>
#include <openbsc/rest_octets.h>
#include <osmocore/bitvec.h>
#include <openbsc/debug.h>
#define GSM48_CELL_CHAN_DESC_SIZE 16
#define GSM_MACBLOCK_LEN 23
#define GSM_MACBLOCK_PADDING 0x2b
/* verify the sizes of the system information type structs */
/* rest octets are not part of the struct */
static_assert(sizeof(struct gsm48_system_information_type_header) == 3, _si_header_size);
static_assert(sizeof(struct gsm48_rach_control) == 3, _si_rach_control);
static_assert(sizeof(struct gsm48_system_information_type_1) == 22, _si1_size);
static_assert(sizeof(struct gsm48_system_information_type_2) == 23, _si2_size);
static_assert(sizeof(struct gsm48_system_information_type_3) == 19, _si3_size);
static_assert(sizeof(struct gsm48_system_information_type_4) == 13, _si4_size);
/* bs11 forgot the l2 len, 0-6 rest octets */
static_assert(sizeof(struct gsm48_system_information_type_5) == 18, _si5_size);
static_assert(sizeof(struct gsm48_system_information_type_6) == 11, _si6_size);
static_assert(sizeof(struct gsm48_system_information_type_13) == 3, _si13_size);
/* Frequency Lists as per TS 04.08 10.5.2.13 */
/* 10.5.2.13.2: Bit map 0 format */
static int freq_list_bm0_set_arfcn(u_int8_t *chan_list, unsigned int arfcn)
{
unsigned int byte, bit;
if (arfcn > 124 || arfcn < 1) {
LOGP(DRR, LOGL_ERROR, "Bitmap 0 only supports ARFCN 1...124\n");
return -EINVAL;
}
/* the bitmask is from 1..124, not from 0..123 */
arfcn--;
byte = arfcn / 8;
bit = arfcn % 8;
chan_list[GSM48_CELL_CHAN_DESC_SIZE-1-byte] |= (1 << bit);
return 0;
}
/* 10.5.2.13.7: Variable bit map format */
static int freq_list_bmrel_set_arfcn(u_int8_t *chan_list, unsigned int arfcn)
{
unsigned int byte, bit;
unsigned int min_arfcn;
unsigned int bitno;
min_arfcn = (chan_list[0] & 1) << 9;
min_arfcn |= chan_list[1] << 1;
min_arfcn |= (chan_list[2] >> 7) & 1;
/* The lower end of our bitmaks is always implicitly included */
if (arfcn == min_arfcn)
return 0;
if (arfcn < min_arfcn) {
LOGP(DRR, LOGL_ERROR, "arfcn(%u) < min(%u)\n", arfcn, min_arfcn);
return -EINVAL;
}
if (arfcn > min_arfcn + 111) {
LOGP(DRR, LOGL_ERROR, "arfcn(%u) > min(%u) + 111\n", arfcn, min_arfcn);
return -EINVAL;
}
bitno = (arfcn - min_arfcn);
byte = bitno / 8;
bit = bitno % 8;
chan_list[2 + byte] |= 1 << (7 - bit);
return 0;
}
/* generate a cell channel list as per Section 10.5.2.1b of 04.08 */
static int bitvec2freq_list(u_int8_t *chan_list, struct bitvec *bv,
const struct gsm_bts *bts)
{
int i, rc, min = 1024, max = -1;
memset(chan_list, 0, 16);
/* GSM900-only handsets only support 'bit map 0 format' */
if (bts->band == GSM_BAND_900) {
chan_list[0] = 0;
for (i = 0; i < bv->data_len*8; i++) {
if (bitvec_get_bit_pos(bv, i)) {
rc = freq_list_bm0_set_arfcn(chan_list, i);
if (rc < 0)
return rc;
}
}
return 0;
}
/* We currently only support the 'Variable bitmap format' */
chan_list[0] = 0x8e;
for (i = 0; i < bv->data_len*8; i++) {
if (bitvec_get_bit_pos(bv, i)) {
if (i < min)
min = i;
if (i > max)
max = i;
}
}
if (max == -1) {
/* Empty set, use 'bit map 0 format' */
chan_list[0] = 0;
return 0;
}
if ((max - min) > 111) {
LOGP(DRR, LOGL_ERROR, "min_arfcn=%u, max_arfcn=%u, "
"distance > 111\n", min, max);
return -EINVAL;
}
chan_list[0] |= (min >> 9) & 1;
chan_list[1] = (min >> 1);
chan_list[2] = (min & 1) << 7;
for (i = 0; i < bv->data_len*8; i++) {
if (bitvec_get_bit_pos(bv, i)) {
rc = freq_list_bmrel_set_arfcn(chan_list, i);
if (rc < 0)
return rc;
}
}
return 0;
}
/* generate a cell channel list as per Section 10.5.2.1b of 04.08 */
static int generate_cell_chan_list(u_int8_t *chan_list, struct gsm_bts *bts)
{
struct gsm_bts_trx *trx;
struct bitvec *bv = &bts->si_common.cell_alloc;
/* first we generate a bitvec of all TRX ARFCN's in our BTS */
llist_for_each_entry(trx, &bts->trx_list, list)
bitvec_set_bit_pos(bv, trx->arfcn, 1);
/* then we generate a GSM 04.08 frequency list from the bitvec */
return bitvec2freq_list(chan_list, bv, bts);
}
/* generate a cell channel list as per Section 10.5.2.1b of 04.08 */
static int generate_bcch_chan_list(u_int8_t *chan_list, struct gsm_bts *bts)
{
struct gsm_bts *cur_bts;
struct bitvec *bv = &bts->si_common.neigh_list;
/* first we generate a bitvec of the BCCH ARFCN's in our BSC */
llist_for_each_entry(cur_bts, &bts->network->bts_list, list) {
if (cur_bts == bts)
continue;
bitvec_set_bit_pos(bv, cur_bts->c0->arfcn, 1);
}
/* then we generate a GSM 04.08 frequency list from the bitvec */
return bitvec2freq_list(chan_list, bv, bts);
}
static int generate_si1(u_int8_t *output, struct gsm_bts *bts)
{
int rc;
struct gsm48_system_information_type_1 *si1 =
(struct gsm48_system_information_type_1 *) output;
memset(si1, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
si1->header.l2_plen = (21 << 2) | 1;
si1->header.rr_protocol_discriminator = GSM48_PDISC_RR;
si1->header.skip_indicator = 0;
si1->header.system_information = GSM48_MT_RR_SYSINFO_1;
rc = generate_cell_chan_list(si1->cell_channel_description, bts);
if (rc < 0)
return rc;
si1->rach_control = bts->si_common.rach_control;
/* SI1 Rest Octets (10.5.2.32), contains NCH position */
rc = rest_octets_si1(si1->rest_octets, NULL);
return sizeof(*si1) + rc;
}
static int generate_si2(u_int8_t *output, struct gsm_bts *bts)
{
int rc;
struct gsm48_system_information_type_2 *si2 =
(struct gsm48_system_information_type_2 *) output;
memset(si2, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
si2->header.l2_plen = (22 << 2) | 1;
si2->header.rr_protocol_discriminator = GSM48_PDISC_RR;
si2->header.skip_indicator = 0;
si2->header.system_information = GSM48_MT_RR_SYSINFO_2;
rc = generate_bcch_chan_list(si2->bcch_frequency_list, bts);
if (rc < 0)
return rc;
si2->ncc_permitted = bts->si_common.ncc_permitted;
si2->rach_control = bts->si_common.rach_control;
return sizeof(*si2);
}
struct gsm48_si_ro_info si_info = {
.selection_params = {
.present = 0,
},
.power_offset = {
.present = 0,
},
.si2ter_indicator = 0,
.early_cm_ctrl = 1,
.scheduling = {
.present = 0,
},
.gprs_ind = {
.si13_position = 0,
.ra_colour = 0,
.present = 0,
},
.lsa_params = {
.present = 0,
},
.cell_id = 0, /* FIXME: doesn't the bts have this? */
.break_ind = 0,
};
static int generate_si3(u_int8_t *output, struct gsm_bts *bts)
{
int rc;
struct gsm48_system_information_type_3 *si3 =
(struct gsm48_system_information_type_3 *) output;
memset(si3, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
si3->header.l2_plen = (18 << 2) | 1;
si3->header.rr_protocol_discriminator = GSM48_PDISC_RR;
si3->header.skip_indicator = 0;
si3->header.system_information = GSM48_MT_RR_SYSINFO_3;
si3->cell_identity = htons(bts->cell_identity);
gsm0408_generate_lai(&si3->lai, bts->network->country_code,
bts->network->network_code,
bts->location_area_code);
si3->control_channel_desc = bts->si_common.chan_desc;
si3->cell_options = bts->si_common.cell_options;
si3->cell_sel_par = bts->si_common.cell_sel_par;
si3->rach_control = bts->si_common.rach_control;
/* SI3 Rest Octets (10.5.2.34), containing
CBQ, CELL_RESELECT_OFFSET, TEMPORARY_OFFSET, PENALTY_TIME
Power Offset, 2ter Indicator, Early Classmark Sending,
Scheduling if and WHERE, GPRS Indicator, SI13 position */
rc = rest_octets_si3(si3->rest_octets, &si_info);
return sizeof(*si3) + rc;
}
static int generate_si4(u_int8_t *output, struct gsm_bts *bts)
{
int rc;
struct gsm48_system_information_type_4 *si4 =
(struct gsm48_system_information_type_4 *) output;
/* length of all IEs present except SI4 rest octets and l2_plen */
int l2_plen = sizeof(*si4) - 1;
memset(si4, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
si4->header.rr_protocol_discriminator = GSM48_PDISC_RR;
si4->header.skip_indicator = 0;
si4->header.system_information = GSM48_MT_RR_SYSINFO_4;
gsm0408_generate_lai(&si4->lai, bts->network->country_code,
bts->network->network_code,
bts->location_area_code);
si4->cell_sel_par = bts->si_common.cell_sel_par;
si4->rach_control = bts->si_common.rach_control;
/* Optional: CBCH Channel Description + CBCH Mobile Allocation */
si4->header.l2_plen = (l2_plen << 2) | 1;
/* SI4 Rest Octets (10.5.2.35), containing
Optional Power offset, GPRS Indicator,
Cell Identity, LSA ID, Selection Parameter */
rc = rest_octets_si4(si4->data, &si_info);
return sizeof(*si4) + rc;
}
static int generate_si5(u_int8_t *output, struct gsm_bts *bts)
{
struct gsm48_system_information_type_5 *si5;
int rc, l2_plen = 18;
memset(output, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
/* ip.access nanoBTS needs l2_plen!! */
if (is_ipaccess_bts(bts)) {
*output++ = (l2_plen << 2) | 1;
l2_plen++;
}
si5 = (struct gsm48_system_information_type_5 *) output;
/* l2 pseudo length, not part of msg: 18 */
si5->rr_protocol_discriminator = GSM48_PDISC_RR;
si5->skip_indicator = 0;
si5->system_information = GSM48_MT_RR_SYSINFO_5;
rc = generate_bcch_chan_list(si5->bcch_frequency_list, bts);
if (rc < 0)
return rc;
/* 04.08 9.1.37: L2 Pseudo Length of 18 */
return l2_plen;
}
static int generate_si6(u_int8_t *output, struct gsm_bts *bts)
{
struct gsm48_system_information_type_6 *si6;
int l2_plen = 11;
memset(output, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
/* ip.access nanoBTS needs l2_plen!! */
if (is_ipaccess_bts(bts)) {
*output++ = (l2_plen << 2) | 1;
l2_plen++;
}
si6 = (struct gsm48_system_information_type_6 *) output;
/* l2 pseudo length, not part of msg: 11 */
si6->rr_protocol_discriminator = GSM48_PDISC_RR;
si6->skip_indicator = 0;
si6->system_information = GSM48_MT_RR_SYSINFO_6;
si6->cell_identity = htons(bts->cell_identity);
gsm0408_generate_lai(&si6->lai, bts->network->country_code,
bts->network->network_code,
bts->location_area_code);
si6->cell_options = bts->si_common.cell_options;
si6->ncc_permitted = bts->si_common.ncc_permitted;
/* SI6 Rest Octets: 10.5.2.35a: PCH / NCH info, VBS/VGCS options */
return l2_plen;
}
static struct gsm48_si13_info si13_default = {
.cell_opts = {
.nmo = GPRS_NMO_III,
.t3168 = 1000,
.t3192 = 1000,
.drx_timer_max = 1,
.bs_cv_max = 15,
},
.pwr_ctrl_pars = {
.alpha = 10, /* a = 1.0 */
.t_avg_w = 25,
.t_avg_t = 25,
.pc_meas_chan = 0, /* downling measured on CCCH */
.n_avg_i = 15,
},
.bcch_change_mark = 0,
.si_change_field = 0,
.pbcch_present = 0,
{
.no_pbcch = {
.rac = 0,
.spgc_ccch_sup = 0,
.net_ctrl_ord = 0,
.prio_acc_thr = 0,
},
},
};
static int generate_si13(u_int8_t *output, struct gsm_bts *bts)
{
struct gsm48_system_information_type_13 *si13 =
(struct gsm48_system_information_type_13 *) output;
int ret;
memset(si13, GSM_MACBLOCK_PADDING, GSM_MACBLOCK_LEN);
si13->header.rr_protocol_discriminator = GSM48_PDISC_RR;
si13->header.skip_indicator = 0;
si13->header.system_information = GSM48_MT_RR_SYSINFO_13;
ret = rest_octets_si13(si13->rest_octets, &si13_default);
if (ret < 0)
return ret;
si13->header.l2_plen = ret & 0xff;
return sizeof (*si13) + ret;
}
int gsm_generate_si(u_int8_t *output, struct gsm_bts *bts, int type)
{
switch (type) {
case RSL_SYSTEM_INFO_1:
return generate_si1(output, bts);
case RSL_SYSTEM_INFO_2:
return generate_si2(output, bts);
case RSL_SYSTEM_INFO_3:
return generate_si3(output, bts);
case RSL_SYSTEM_INFO_4:
return generate_si4(output, bts);
case RSL_SYSTEM_INFO_5:
return generate_si5(output, bts);
case RSL_SYSTEM_INFO_6:
return generate_si6(output, bts);
case RSL_SYSTEM_INFO_13:
return generate_si13(output, bts);
default:
return -EINVAL;
}
return 0;
}
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