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Diffstat (limited to 'src/gsm/gsm_utils.c')
-rw-r--r-- | src/gsm/gsm_utils.c | 465 |
1 files changed, 465 insertions, 0 deletions
diff --git a/src/gsm/gsm_utils.c b/src/gsm/gsm_utils.c new file mode 100644 index 00000000..54a13ad8 --- /dev/null +++ b/src/gsm/gsm_utils.c @@ -0,0 +1,465 @@ +/* + * (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; +} |