libosmogsm  0.9.6-11.20170220git32ee5af8.fc31
Osmocom GSM library
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 #pragma once
26 
27 #include <stddef.h>
28 #include <stdint.h>
29 
30 #include <osmocom/core/defs.h>
31 #include <osmocom/core/utils.h>
32 
33 #define ADD_MODULO(sum, delta, modulo) do { \
34  if ((sum += delta) >= modulo) \
35  sum -= modulo; \
36  } while (0)
37 
38 #define GSM_MAX_FN (26*51*2048)
39 
40 struct gsm_time {
41  uint32_t fn; /* FN count */
42  uint16_t t1; /* FN div (26*51) */
43  uint8_t t2; /* FN modulo 26 */
44  uint8_t t3; /* FN modulo 51 */
45  uint8_t tc;
46 };
47 
48 enum gsm_band {
49  GSM_BAND_850 = 1,
50  GSM_BAND_900 = 2,
51  GSM_BAND_1800 = 4,
52  GSM_BAND_1900 = 8,
53  GSM_BAND_450 = 0x10,
54  GSM_BAND_480 = 0x20,
55  GSM_BAND_750 = 0x40,
56  GSM_BAND_810 = 0x80,
57 };
58 
59 const char *gsm_band_name(enum gsm_band band);
60 enum gsm_band gsm_band_parse(const char *mhz);
61 
76 int gsm_7bit_decode_n(char *decoded, size_t n, const uint8_t *user_data, uint8_t length);
77 
83 int gsm_7bit_decode_n_ussd(char *decoded, size_t n, const uint8_t *user_data, uint8_t length);
84 
97 int gsm_7bit_encode_n(uint8_t *result, size_t n, const char *data, int *octets_written);
98 
104 int gsm_7bit_encode_n_ussd(uint8_t *result, size_t n, const char *data, int *octets_written);
105 
106 /* the four functions below are helper functions and here for the unit test */
107 int gsm_septets2octets(uint8_t *result, const uint8_t *rdata, uint8_t septet_len, uint8_t padding);
108 int gsm_septet_encode(uint8_t *result, const char *data);
109 uint8_t gsm_get_octet_len(const uint8_t sept_len);
110 int gsm_7bit_decode_n_hdr(char *decoded, size_t n, const uint8_t *user_data, uint8_t length, uint8_t ud_hdr_ind);
111 
112 unsigned int ms_class_gmsk_dbm(enum gsm_band band, int ms_class);
113 
114 int ms_pwr_ctl_lvl(enum gsm_band band, unsigned int dbm);
115 int ms_pwr_dbm(enum gsm_band band, uint8_t lvl);
116 
117 /* According to TS 05.08 Chapter 8.1.4 */
118 int rxlev2dbm(uint8_t rxlev);
119 uint8_t dbm2rxlev(int dbm);
120 
121 /* According to GSM 04.08 Chapter 10.5.1.6 */
122 static inline int ms_cm2_a5n_support(uint8_t *cm2, unsigned n) {
123  switch (n) {
124  case 0: return 1;
125  case 1: return (cm2[0] & (1<<3)) ? 0 : 1;
126  case 2: return (cm2[2] & (1<<0)) ? 1 : 0;
127  case 3: return (cm2[2] & (1<<1)) ? 1 : 0;
128  default:
129  return 0;
130  }
131 }
132 
133 /* According to GSM 04.08 Chapter 10.5.1.7 */
134 static inline int ms_cm3_a5n_support(uint8_t *cm3, unsigned n) {
135  switch (n) {
136  case 4: return (cm3[0] & (1<<0)) ? 1 : 0;
137  case 5: return (cm3[0] & (1<<1)) ? 1 : 0;
138  case 6: return (cm3[0] & (1<<2)) ? 1 : 0;
139  case 7: return (cm3[0] & (1<<3)) ? 1 : 0;
140  default:
141  return 0;
142  }
143 }
144 
145 /* According to GSM 04.08 Chapter 10.5.2.29 */
146 static inline int rach_max_trans_val2raw(int val) { return (val >> 1) & 3; }
147 static inline int rach_max_trans_raw2val(int raw) {
148  const int tbl[4] = { 1, 2, 4, 7 };
149  return tbl[raw & 3];
150 }
151 
152 #define ARFCN_PCS 0x8000
153 #define ARFCN_UPLINK 0x4000
154 #define ARFCN_FLAG_MASK 0xf000 /* Reserve the upper 5 bits for flags */
155 
156 enum gsm_band gsm_arfcn2band(uint16_t arfcn);
157 
158 /* Convert an ARFCN to the frequency in MHz * 10 */
159 uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink);
160 
161 /* Convert a Frequency in MHz * 10 to ARFCN */
162 uint16_t gsm_freq102arfcn(uint16_t freq10, int uplink);
163 
164 /* Convert from frame number to GSM time */
165 void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn);
166 
167 /* Convert from GSM time to frame number */
168 uint32_t gsm_gsmtime2fn(struct gsm_time *time);
169 
170 /* GSM TS 03.03 Chapter 2.6 */
171 enum gprs_tlli_type {
172  TLLI_LOCAL,
173  TLLI_FOREIGN,
174  TLLI_RANDOM,
175  TLLI_AUXILIARY,
176  TLLI_RESERVED,
177  TLLI_G_RNTI,
178  TLLI_RAND_G_RNTI,
179 };
180 
181 /* TS 03.03 Chapter 2.6 */
182 int gprs_tlli_type(uint32_t tlli);
183 
184 uint32_t gprs_tmsi2tlli(uint32_t p_tmsi, enum gprs_tlli_type type);
185 
186 /* Osmocom internal, not part of any gsm spec */
187 enum gsm_phys_chan_config {
188  GSM_PCHAN_NONE,
189  GSM_PCHAN_CCCH,
190  GSM_PCHAN_CCCH_SDCCH4,
191  GSM_PCHAN_TCH_F,
192  GSM_PCHAN_TCH_H,
193  GSM_PCHAN_SDCCH8_SACCH8C,
194  GSM_PCHAN_PDCH, /* GPRS PDCH */
195  GSM_PCHAN_TCH_F_PDCH, /* TCH/F if used, PDCH otherwise */
196  GSM_PCHAN_UNKNOWN,
197  GSM_PCHAN_CCCH_SDCCH4_CBCH,
198  GSM_PCHAN_SDCCH8_SACCH8C_CBCH,
199  GSM_PCHAN_TCH_F_TCH_H_PDCH,
200  _GSM_PCHAN_MAX
201 };
202 
203 /* Osmocom internal, not part of any gsm spec */
204 enum gsm_chan_t {
205  GSM_LCHAN_NONE,
206  GSM_LCHAN_SDCCH,
207  GSM_LCHAN_TCH_F,
208  GSM_LCHAN_TCH_H,
209  GSM_LCHAN_UNKNOWN,
210  GSM_LCHAN_CCCH,
211  GSM_LCHAN_PDTCH,
212  GSM_LCHAN_CBCH,
213  _GSM_LCHAN_MAX
214 };
215 
216 extern const struct value_string gsm_chan_t_names[];
217 
218 /* Deprectated functions */
219 /* Limit encoding and decoding to use no more than this amount of buffer bytes */
220 #define GSM_7BIT_LEGACY_MAX_BUFFER_SIZE 0x10000
221 
222 int gsm_7bit_decode(char *decoded, const uint8_t *user_data, uint8_t length) OSMO_DEPRECATED("Use gsm_7bit_decode_n() instead");
223 int gsm_7bit_decode_ussd(char *decoded, const uint8_t *user_data, uint8_t length) OSMO_DEPRECATED("Use gsm_7bit_decode_n_ussd() instead");
224 int gsm_7bit_encode(uint8_t *result, const char *data) OSMO_DEPRECATED("Use gsm_7bit_encode_n() instead");
225 int gsm_7bit_encode_ussd(uint8_t *result, const char *data, int *octets_written) OSMO_DEPRECATED("Use gsm_7bit_encode_n_ussd() instead");
226 int gsm_7bit_encode_oct(uint8_t *result, const char *data, int *octets_written) OSMO_DEPRECATED("Use gsm_7bit_encode_n() instead");
uint8_t data[0]
actual payload data
Definition: gsm_08_58.h:443
Definition: gsm_utils.h:40
uint8_t length
Length in octets.
Definition: gsm_12_21.h:452