/* GSM utility functions, e.g. coding and decoding */ /* * (C) 2008 by Daniel Willmann * (C) 2009 by Holger Hans Peter Freyther * (C) 2009-2010 by Harald Welte * * 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. * */ #pragma once #include #include #include #define ADD_MODULO(sum, delta, modulo) do { \ if ((sum += delta) >= modulo) \ sum -= modulo; \ } while (0) #define GSM_MAX_FN (26*51*2048) struct gsm_time { uint32_t fn; /* FN count */ uint16_t t1; /* FN div (26*51) */ uint8_t t2; /* FN modulo 26 */ uint8_t t3; /* FN modulo 51 */ uint8_t tc; }; enum gsm_band { GSM_BAND_850 = 1, GSM_BAND_900 = 2, GSM_BAND_1800 = 4, GSM_BAND_1900 = 8, GSM_BAND_450 = 0x10, GSM_BAND_480 = 0x20, GSM_BAND_750 = 0x40, GSM_BAND_810 = 0x80, }; const char *gsm_band_name(enum gsm_band band); enum gsm_band gsm_band_parse(const char *mhz); /*! * \brief Decode a sequence of GSM 03.38 encoded 7 bit characters. * * \param decoded The destination buffer for the decoded characters. * \param n A maximum of n chars is written (incl. terminating \0). * Requires n >= 1. * \param user_data A pointer to the start of the packed 7bit character * sequence. * \param length The length of the input sequence (in octets). * * \returns the number of (8 bit) chars written excluding the terminating \0. * This is the same like strlen(decoded). */ int gsm_7bit_decode_n(char *decoded, size_t n, const uint8_t *user_data, uint8_t length); /*! * \brief Decode a sequence of 7 bit characters (USSD encoding). * * \see gsm_7bit_encode_n() */ int gsm_7bit_decode_n_ussd(char *decoded, size_t n, const uint8_t *user_data, uint8_t length); /*! * \brief Encode a text string into GSM 03.38 encoded 7 bit characters. * * \param result The destination buffer for the packed 7 bit sequence. * \param n A maximum of n octets is written. * \param data A pointer to the start of the \0 terminated 8 bit character * string. * \param octets_written Iff not NULL, *octets_written will be set to the * number of octets written to the result buffer. * * \returns the number of septets that have been created. */ int gsm_7bit_encode_n(uint8_t *result, size_t n, const char *data, int *octets_written); /*! * \brief Encode a text string into GSM 03.38 encoded 7 bit characters (USSD encoding). * * \see gsm_7bit_decode_n() */ int gsm_7bit_encode_n_ussd(uint8_t *result, size_t n, const char *data, int *octets_written); /* the four functions below are helper functions and here for the unit test */ int gsm_septets2octets(uint8_t *result, const uint8_t *rdata, uint8_t septet_len, uint8_t padding); int gsm_septet_encode(uint8_t *result, const char *data); uint8_t gsm_get_octet_len(const uint8_t sept_len); int gsm_7bit_decode_n_hdr(char *decoded, size_t n, const uint8_t *user_data, uint8_t length, uint8_t ud_hdr_ind); unsigned int ms_class_gmsk_dbm(enum gsm_band band, int ms_class); int ms_pwr_ctl_lvl(enum gsm_band band, unsigned int dbm); int ms_pwr_dbm(enum gsm_band band, uint8_t lvl); /* According to TS 05.08 Chapter 8.1.4 */ int rxlev2dbm(uint8_t rxlev); uint8_t dbm2rxlev(int dbm); /* According to GSM 04.08 Chapter 10.5.1.6 */ static inline int ms_cm2_a5n_support(uint8_t *cm2, int n) { switch (n) { case 0: return 1; case 1: return (cm2[0] & (1<<3)) ? 0 : 1; case 2: return (cm2[2] & (1<<0)) ? 1 : 0; case 3: return (cm2[2] & (1<<1)) ? 1 : 0; default: return 0; } } /* According to GSM 04.08 Chapter 10.5.2.29 */ static inline int rach_max_trans_val2raw(int val) { return (val >> 1) & 3; } static inline int rach_max_trans_raw2val(int raw) { const int tbl[4] = { 1, 2, 4, 7 }; return tbl[raw & 3]; } #define ARFCN_PCS 0x8000 #define ARFCN_UPLINK 0x4000 #define ARFCN_FLAG_MASK 0xf000 /* Reserve the upper 5 bits for flags */ enum gsm_band gsm_arfcn2band(uint16_t arfcn); /* Convert an ARFCN to the frequency in MHz * 10 */ uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink); /* Convert a Frequency in MHz * 10 to ARFCN */ uint16_t gsm_freq102arfcn(uint16_t freq10, int uplink); /* Convert from frame number to GSM time */ void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn); /* Convert from GSM time to frame number */ uint32_t gsm_gsmtime2fn(struct gsm_time *time); /* GSM TS 03.03 Chapter 2.6 */ enum gprs_tlli_type { TLLI_LOCAL, TLLI_FOREIGN, TLLI_RANDOM, TLLI_AUXILIARY, TLLI_RESERVED, }; /* TS 03.03 Chapter 2.6 */ int gprs_tlli_type(uint32_t tlli); uint32_t gprs_tmsi2tlli(uint32_t p_tmsi, enum gprs_tlli_type type); /* Osmocom internal, not part of any gsm spec */ enum gsm_phys_chan_config { GSM_PCHAN_NONE, GSM_PCHAN_CCCH, GSM_PCHAN_CCCH_SDCCH4, GSM_PCHAN_TCH_F, GSM_PCHAN_TCH_H, GSM_PCHAN_SDCCH8_SACCH8C, GSM_PCHAN_PDCH, /* GPRS PDCH */ GSM_PCHAN_TCH_F_PDCH, /* TCH/F if used, PDCH otherwise */ GSM_PCHAN_UNKNOWN, _GSM_PCHAN_MAX }; /* Osmocom internal, not part of any gsm spec */ enum gsm_chan_t { GSM_LCHAN_NONE, GSM_LCHAN_SDCCH, GSM_LCHAN_TCH_F, GSM_LCHAN_TCH_H, GSM_LCHAN_UNKNOWN, GSM_LCHAN_CCCH, GSM_LCHAN_PDTCH, _GSM_LCHAN_MAX }; /* Deprectated functions */ /* Limit encoding and decoding to use no more than this amount of buffer bytes */ #define GSM_7BIT_LEGACY_MAX_BUFFER_SIZE 0x10000 int gsm_7bit_decode(char *decoded, const uint8_t *user_data, uint8_t length) OSMO_DEPRECATED("Use gsm_7bit_decode_n() instead"); int gsm_7bit_decode_ussd(char *decoded, const uint8_t *user_data, uint8_t length) OSMO_DEPRECATED("Use gsm_7bit_decode_n_ussd() instead"); int gsm_7bit_encode(uint8_t *result, const char *data) OSMO_DEPRECATED("Use gsm_7bit_encode_n() instead"); int gsm_7bit_encode_ussd(uint8_t *result, const char *data, int *octets_written) OSMO_DEPRECATED("Use gsm_7bit_encode_n_ussd() instead"); int gsm_7bit_encode_oct(uint8_t *result, const char *data, int *octets_written) OSMO_DEPRECATED("Use gsm_7bit_encode_n() instead");