include/osmocom/gsm/gsm_utils.h

   1 /* GSM utility functions, e.g. coding and decoding */
   2 /*
   3  * (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de>
   4  * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
   5  * (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
   6  *
   7  * All Rights Reserved
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  *
  23  */
  24
  25 #ifndef GSM_UTILS_H
  26 #define GSM_UTILS_H
  27
  28 #include <stdint.h>
  29
  30 #define ADD_MODULO(sum, delta, modulo) do {     \
  31         if ((sum += delta) >= modulo)           \
  32                 sum -= modulo;                  \
  33         } while (0)
  34
  35 #define GSM_MAX_FN      (26*51*2048)
  36
  37 struct gsm_time {
  38         uint32_t        fn;     /* FN count */
  39         uint16_t        t1;     /* FN div (26*51) */
  40         uint8_t         t2;     /* FN modulo 26 */
  41         uint8_t         t3;     /* FN modulo 51 */
  42         uint8_t         tc;
  43 };
  44
  45 enum gsm_band {
  46         GSM_BAND_850    = 1,
  47         GSM_BAND_900    = 2,
  48         GSM_BAND_1800   = 4,
  49         GSM_BAND_1900   = 8,
  50         GSM_BAND_450    = 0x10,
  51         GSM_BAND_480    = 0x20,
  52         GSM_BAND_750    = 0x40,
  53         GSM_BAND_810    = 0x80,
  54 };
  55
  56 const char *gsm_band_name(enum gsm_band band);
  57 enum gsm_band gsm_band_parse(const char *mhz);
  58
  59 int gsm_7bit_decode(char *decoded, const uint8_t *user_data, uint8_t length);
  60 int gsm_7bit_decode_hdr(char *decoded, const uint8_t *user_data, uint8_t length, uint8_t ud_hdr_ind);
  61 int gsm_7bit_encode(uint8_t *result, const char *data);
  62
  63 int gsm_septets2octets(uint8_t *result, uint8_t *rdata, uint8_t septet_len, uint8_t padding);
  64 int gsm_septet_encode(uint8_t *result, const char *data);
  65 uint8_t gsm_get_octet_len(const uint8_t sept_len);
  66
  67 unsigned int ms_class_gmsk_dbm(enum gsm_band band, int ms_class);
  68
  69 int ms_pwr_ctl_lvl(enum gsm_band band, unsigned int dbm);
  70 int ms_pwr_dbm(enum gsm_band band, uint8_t lvl);
  71
  72 /* According to TS 08.05 Chapter 8.1.4 */
  73 int rxlev2dbm(uint8_t rxlev);
  74 uint8_t dbm2rxlev(int dbm);
  75
  76 /* According to GSM 04.08 Chapter 10.5.1.6 */
  77 static inline int ms_cm2_a5n_support(uint8_t *cm2, int n) {
  78         switch (n) {
  79                 case 0: return 1;
  80                 case 1: return (cm2[0] & (1<<3)) ? 0 : 1;
  81                 case 2: return (cm2[2] & (1<<0)) ? 1 : 0;
  82                 case 3: return (cm2[2] & (1<<1)) ? 1 : 0;
  83                 default:
  84                         return 0;
  85         }
  86 }
  87
  88 /* According to GSM 04.08 Chapter 10.5.2.29 */
  89 static inline int rach_max_trans_val2raw(int val) { return (val >> 1) & 3; }
  90 static inline int rach_max_trans_raw2val(int raw) {
  91         const int tbl[4] = { 1, 2, 4, 7 };
  92         return tbl[raw & 3];
  93 }
  94
  95 #define ARFCN_PCS       0x8000
  96 #define ARFCN_UPLINK    0x4000
  97 #define ARFCN_FLAG_MASK 0xf000  /* Reserve the upper 5 bits for flags */
  98
  99 enum gsm_band gsm_arfcn2band(uint16_t arfcn);
 100
 101 /* Convert an ARFCN to the frequency in MHz * 10 */
 102 uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink);
 103
 104 /* Convert from frame number to GSM time */
 105 void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn);
 106
 107 /* Convert from GSM time to frame number */
 108 uint32_t gsm_gsmtime2fn(struct gsm_time *time);
 109
 110 /* GSM TS 03.03 Chapter 2.6 */
 111 enum gprs_tlli_type {
 112         TLLI_LOCAL,
 113         TLLI_FOREIGN,
 114         TLLI_RANDOM,
 115         TLLI_AUXILIARY,
 116         TLLI_RESERVED,
 117 };
 118
 119 /* TS 03.03 Chapter 2.6 */
 120 int gprs_tlli_type(uint32_t tlli);
 121
 122 uint32_t gprs_tmsi2tlli(uint32_t p_tmsi, enum gprs_tlli_type type);
 123
 124 /* Osmocom internal, not part of any gsm spec */
 125 enum gsm_phys_chan_config {
 126         GSM_PCHAN_NONE,
 127         GSM_PCHAN_CCCH,
 128         GSM_PCHAN_CCCH_SDCCH4,
 129         GSM_PCHAN_TCH_F,
 130         GSM_PCHAN_TCH_H,
 131         GSM_PCHAN_SDCCH8_SACCH8C,
 132         GSM_PCHAN_PDCH,         /* GPRS PDCH */
 133         GSM_PCHAN_TCH_F_PDCH,   /* TCH/F if used, PDCH otherwise */
 134         GSM_PCHAN_UNKNOWN,
 135         _GSM_PCHAN_MAX
 136 };
 137
 138 /* Osmocom internal, not part of any gsm spec */
 139 enum gsm_chan_t {
 140         GSM_LCHAN_NONE,
 141         GSM_LCHAN_SDCCH,
 142         GSM_LCHAN_TCH_F,
 143         GSM_LCHAN_TCH_H,
 144         GSM_LCHAN_UNKNOWN,
 145         GSM_LCHAN_CCCH,
 146         _GSM_LCHAN_MAX
 147 };
 148
 149
 150 #endif