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libosmocore/src/gsm/gsm_utils.c

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/*
* (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de>
* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
* (C) 2010 by Nico Golde <nico@ngolde.de>
*
* 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 <openbsc/gsm_data.h>
#include <osmocore/utils.h>
#include <osmocore/gsm_utils.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include "../config.h"
/* ETSI GSM 03.38 6.2.1 and 6.2.1.1 default alphabet
* Greek symbols at hex positions 0x10 and 0x12-0x1a
* left out as they can't be handled with a char and
* since most phones don't display or write these
* characters this would only needlessly make the code
* more complex
*/
static unsigned char gsm_7bit_alphabet[] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0a, 0xff, 0xff, 0x0d, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0x20, 0x21, 0x22, 0x23, 0x02, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c,
0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
0x3c, 0x3d, 0x3e, 0x3f, 0x00, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x5a, 0x3c, 0x2f, 0x3e, 0x14, 0x11, 0xff, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
0x78, 0x79, 0x7a, 0x28, 0x40, 0x29, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0x0c, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5e, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x40, 0xff, 0x01, 0xff,
0x03, 0xff, 0x7b, 0x7d, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5c, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5b, 0x7e, 0x5d, 0xff, 0x7c, 0xff, 0xff, 0xff,
0xff, 0x5b, 0x0e, 0x1c, 0x09, 0xff, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5d,
0xff, 0xff, 0xff, 0xff, 0x5c, 0xff, 0x0b, 0xff, 0xff, 0xff, 0x5e, 0xff, 0xff, 0x1e, 0x7f,
0xff, 0xff, 0xff, 0x7b, 0x0f, 0x1d, 0xff, 0x04, 0x05, 0xff, 0xff, 0x07, 0xff, 0xff, 0xff,
0xff, 0x7d, 0x08, 0xff, 0xff, 0xff, 0x7c, 0xff, 0x0c, 0x06, 0xff, 0xff, 0x7e, 0xff, 0xff
};
/* GSM 03.38 6.2.1 Character lookup for decoding */
static int gsm_septet_lookup(uint8_t ch)
{
int i = 0;
for(; i < sizeof(gsm_7bit_alphabet); i++){
if(gsm_7bit_alphabet[i] == ch)
return i;
}
return -1;
}
/* GSM 03.38 6.2.1 Character unpacking */
int gsm_7bit_decode(char *text, const uint8_t *user_data, uint8_t length)
{
int i = 0;
int l = 0;
int septet_l = (length * 8) / 7;
uint8_t *rtext = calloc(septet_l, sizeof(uint8_t));
uint8_t tmp;
/* FIXME: We need to account for user data headers here */
i += l;
for (; i < septet_l; i++){
rtext[i] =
((user_data[(i * 7 + 7) >> 3] <<
(7 - ((i * 7 + 7) & 7))) |
(user_data[(i * 7) >> 3] >>
((i * 7) & 7))) & 0x7f;
}
for(i = 0; i < septet_l; i++){
/* this is an extension character */
if(rtext[i] == 0x1b && i + 1 < length){
tmp = rtext[i+1];
*(text++) = gsm_7bit_alphabet[0x7f + tmp];
i++;
continue;
}
*(text++) = gsm_septet_lookup(rtext[i]);
}
*text = '\0';
free(rtext);
return i;
}
/* GSM 03.38 6.2.1 Prepare character packing */
static int gsm_septet_encode(uint8_t *result, const char *data)
{
int i, y = 0;
uint8_t ch;
for(i = 0; i < strlen(data); i++){
ch = data[i];
switch(ch){
/* fall-through for extension characters */
case 0x0c:
case 0x5e:
case 0x7b:
case 0x7d:
case 0x5c:
case 0x5b:
case 0x7e:
case 0x5d:
case 0x7c:
result[y++] = 0x1b;
default:
result[y] = gsm_7bit_alphabet[ch];
break;
}
y++;
}
return y;
}
/* GSM 03.38 6.2.1 Character packing */
int gsm_7bit_encode(uint8_t *result, const char *data)
{
int i,y,z = 0;
/* prepare for the worst case, every character expanding to two bytes */
uint8_t *rdata = calloc(strlen(data) * 2, sizeof(uint8_t));
uint8_t cb, nb;
int shift = 0;
y = gsm_septet_encode(rdata, data);
for(i = 0; i < y; i++) {
if(shift == 7 && i + 1 < y){
shift = 0;
continue;
}
cb = (rdata[i] & 0x7f) >> shift;
if(i + 1 < y){
nb = (rdata[i + 1] & 0x7f) << (7 - shift);
cb = cb | nb;
}
result[z++] = cb;
shift++;
}
free(rdata);
return z;
}
/* determine power control level for given dBm value, as indicated
* by the tables in chapter 4.1.1 of GSM TS 05.05 */
int ms_pwr_ctl_lvl(enum gsm_band band, unsigned int dbm)
{
switch (band) {
case GSM_BAND_450:
case GSM_BAND_480:
case GSM_BAND_750:
case GSM_BAND_900:
case GSM_BAND_810:
case GSM_BAND_850:
if (dbm >= 39)
return 0;
else if (dbm < 5)
return 19;
else {
/* we are guaranteed to have (5 <= dbm < 39) */
return 2 + ((39 - dbm) / 2);
}
break;
case GSM_BAND_1800:
if (dbm >= 36)
return 29;
else if (dbm >= 34)
return 30;
else if (dbm >= 32)
return 31;
else if (dbm == 31)
return 0;
else {
/* we are guaranteed to have (0 <= dbm < 31) */
return (30 - dbm) / 2;
}
break;
case GSM_BAND_1900:
if (dbm >= 33)
return 30;
else if (dbm >= 32)
return 31;
else if (dbm == 31)
return 0;
else {
/* we are guaranteed to have (0 <= dbm < 31) */
return (30 - dbm) / 2;
}
break;
}
return -EINVAL;
}
int ms_pwr_dbm(enum gsm_band band, uint8_t lvl)
{
lvl &= 0x1f;
switch (band) {
case GSM_BAND_450:
case GSM_BAND_480:
case GSM_BAND_750:
case GSM_BAND_900:
case GSM_BAND_810:
case GSM_BAND_850:
if (lvl < 2)
return 39;
else if (lvl < 20)
return 39 - ((lvl - 2) * 2) ;
else
return 5;
break;
case GSM_BAND_1800:
if (lvl < 16)
return 30 - (lvl * 2);
else if (lvl < 29)
return 0;
else
return 36 - ((lvl - 29) * 2);
break;
case GSM_BAND_1900:
if (lvl < 16)
return 30 - (lvl * 2);
else if (lvl < 30)
return -EINVAL;
else
return 33 - (lvl - 30);
break;
}
return -EINVAL;
}
/* According to TS 08.05 Chapter 8.1.4 */
int rxlev2dbm(uint8_t rxlev)
{
if (rxlev > 63)
rxlev = 63;
return -110 + rxlev;
}
/* According to TS 08.05 Chapter 8.1.4 */
uint8_t dbm2rxlev(int dbm)
{
int rxlev = dbm + 110;
if (rxlev > 63)
rxlev = 63;
else if (rxlev < 0)
rxlev = 0;
return rxlev;
}
const char *gsm_band_name(enum gsm_band band)
{
switch (band) {
case GSM_BAND_450:
return "GSM450";
case GSM_BAND_480:
return "GSM480";
case GSM_BAND_750:
return "GSM750";
case GSM_BAND_810:
return "GSM810";
case GSM_BAND_850:
return "GSM850";
case GSM_BAND_900:
return "GSM900";
case GSM_BAND_1800:
return "DCS1800";
case GSM_BAND_1900:
return "PCS1900";
}
return "invalid";
}
enum gsm_band gsm_band_parse(const char* mhz)
{
while (*mhz && !isdigit(*mhz))
mhz++;
if (*mhz == '\0')
return -EINVAL;
switch (strtol(mhz, NULL, 10)) {
case 450:
return GSM_BAND_450;
case 480:
return GSM_BAND_480;
case 750:
return GSM_BAND_750;
case 810:
return GSM_BAND_810;
case 850:
return GSM_BAND_850;
case 900:
return GSM_BAND_900;
case 1800:
return GSM_BAND_1800;
case 1900:
return GSM_BAND_1900;
default:
return -EINVAL;
}
}
enum gsm_band gsm_arfcn2band(uint16_t arfcn)
{
int is_pcs = arfcn & ARFCN_PCS;
arfcn &= ~ARFCN_FLAG_MASK;
if (is_pcs)
return GSM_BAND_1900;
else if (arfcn <= 124)
return GSM_BAND_900;
else if (arfcn >= 955 && arfcn <= 1023)
return GSM_BAND_900;
else if (arfcn >= 128 && arfcn <= 251)
return GSM_BAND_850;
else if (arfcn >= 512 && arfcn <= 885)
return GSM_BAND_1800;
else if (arfcn >= 259 && arfcn <= 293)
return GSM_BAND_450;
else if (arfcn >= 306 && arfcn <= 340)
return GSM_BAND_480;
else if (arfcn >= 350 && arfcn <= 425)
return GSM_BAND_810;
else if (arfcn >= 438 && arfcn <= 511)
return GSM_BAND_750;
else
return GSM_BAND_1800;
}
/* Convert an ARFCN to the frequency in MHz * 10 */
uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink)
{
uint16_t freq10_ul;
uint16_t freq10_dl;
int is_pcs = arfcn & ARFCN_PCS;
arfcn &= ~ARFCN_FLAG_MASK;
if (is_pcs) {
/* DCS 1900 */
arfcn &= ~ARFCN_PCS;
freq10_ul = 18502 + 2 * (arfcn-512);
freq10_dl = freq10_ul + 800;
} else if (arfcn <= 124) {
/* Primary GSM + ARFCN 0 of E-GSM */
freq10_ul = 8900 + 2 * arfcn;
freq10_dl = freq10_ul + 450;
} else if (arfcn >= 955 && arfcn <= 1023) {
/* E-GSM and R-GSM */
freq10_ul = 8900 + 2 * (arfcn - 1024);
freq10_dl = freq10_ul + 450;
} else if (arfcn >= 128 && arfcn <= 251) {
/* GSM 850 */
freq10_ul = 8242 + 2 * (arfcn - 128);
freq10_dl = freq10_ul + 450;
} else if (arfcn >= 512 && arfcn <= 885) {
/* DCS 1800 */
freq10_ul = 17102 + 2 * (arfcn - 512);
freq10_dl = freq10_ul + 950;
} else if (arfcn >= 259 && arfcn <= 293) {
/* GSM 450 */
freq10_ul = 4506 + 2 * (arfcn - 259);
freq10_dl = freq10_ul + 100;
} else if (arfcn >= 306 && arfcn <= 340) {
/* GSM 480 */
freq10_ul = 4790 + 2 * (arfcn - 306);
freq10_dl = freq10_ul + 100;
} else if (arfcn >= 350 && arfcn <= 425) {
/* GSM 810 */
freq10_ul = 8060 + 2 * (arfcn - 350);
freq10_dl = freq10_ul + 450;
} else if (arfcn >= 438 && arfcn <= 511) {
/* GSM 750 */
freq10_ul = 7472 + 2 * (arfcn - 438);
freq10_dl = freq10_ul + 300;
} else
return 0xffff;
if (uplink)
return freq10_ul;
else
return freq10_dl;
}
void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn)
{
time->fn = fn;
time->t1 = time->fn / (26*51);
time->t2 = time->fn % 26;
time->t3 = time->fn % 51;
time->tc = (time->fn / 51) % 8;
}
uint32_t gsm_gsmtime2fn(struct gsm_time *time)
{
/* TS 05.02 Chapter 4.3.3 TDMA frame number */
return (51 * ((time->t3 - time->t2 + 26) % 26) + time->t3 + (26 * 51 * time->t1));
}
/* TS 03.03 Chapter 2.6 */
int gprs_tlli_type(uint32_t tlli)
{
if ((tlli & 0xc0000000) == 0xc0000000)
return TLLI_LOCAL;
else if ((tlli & 0xc0000000) == 0x80000000)
return TLLI_FOREIGN;
else if ((tlli & 0xf8000000) == 0x78000000)
return TLLI_RANDOM;
else if ((tlli & 0xf8000000) == 0x70000000)
return TLLI_AUXILIARY;
return TLLI_RESERVED;
}
uint32_t gprs_tmsi2tlli(uint32_t p_tmsi, enum gprs_tlli_type type)
{
uint32_t tlli;
switch (type) {
case TLLI_LOCAL:
tlli = p_tmsi | 0xc0000000;
break;
case TLLI_FOREIGN:
tlli = (p_tmsi & 0x3fffffff) | 0x80000000;
break;
default:
tlli = 0;
break;
}
return tlli;
}
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