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Diffstat (limited to 'src/gsm_utils.c')
| -rw-r--r-- | src/gsm_utils.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/src/gsm_utils.c b/src/gsm_utils.c new file mode 100644 index 00000000..b0a66a68 --- /dev/null +++ b/src/gsm_utils.c @@ -0,0 +1,215 @@ +/* + * (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de> + * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org> + * (C) 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 <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 "../config.h" + +/* GSM 03.38 6.2.1 Charachter packing */ +int gsm_7bit_decode(char *text, const uint8_t *user_data, uint8_t length) +{ + int i = 0; + int l = 0; + + /* FIXME: We need to account for user data headers here */ + i += l; + for (; i < length; i ++) + *(text ++) = + ((user_data[(i * 7 + 7) >> 3] << + (7 - ((i * 7 + 7) & 7))) | + (user_data[(i * 7) >> 3] >> + ((i * 7) & 7))) & 0x7f; + *text = '\0'; + + return i - l; +} + + +/* GSM 03.38 6.2.1 Charachter packing */ +int gsm_7bit_encode(uint8_t *result, const char *data) +{ + int i,j = 0; + unsigned char ch1, ch2; + int shift = 0; + + for ( i=0; i<strlen(data); i++ ) { + + ch1 = data[i] & 0x7F; + ch1 = ch1 >> shift; + ch2 = data[(i+1)] & 0x7F; + ch2 = ch2 << (7-shift); + + ch1 = ch1 | ch2; + + result[j++] = ch1; + + shift++; + + if ((shift == 7) && (i+1<strlen(data))) { + shift = 0; + i++; + } + } + + return i; +} + +/* 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; +} + +#ifdef HAVE_EXECINFO_H +#include <execinfo.h> +void generate_backtrace() +{ + int i, nptrs; + void *buffer[100]; + char **strings; + + nptrs = backtrace(buffer, ARRAY_SIZE(buffer)); + printf("backtrace() returned %d addresses\n", nptrs); + + strings = backtrace_symbols(buffer, nptrs); + if (!strings) + return; + + for (i = 1; i < nptrs; i++) + printf("%s\n", strings[i]); + + free(strings); +} +#endif |