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Max Suraev Max.Suraev at fairwaves.coSigned-off-by: Max Suraev <Max.Suraev at fairwaves.co> --- include/osmocom/gsm/gsm_utils.h | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/include/osmocom/gsm/gsm_utils.h b/include/osmocom/gsm/gsm_utils.h index 6eab7ac..cf174e2 100644 --- a/include/osmocom/gsm/gsm_utils.h +++ b/include/osmocom/gsm/gsm_utils.h @@ -117,17 +117,41 @@ 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) { +static inline int ms_cm2_a5n_support(uint8_t *cm2, unsigned 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; + return (n > 7) ? 0 : -1; } } +/* According to GSM 04.08 Chapter 10.5.1.7 */ +static inline int ms_cm3_a5n_support(uint8_t *cm3, unsigned n) { + switch (n) { + case 4: return (cm3[0] & (1<<0)) ? 1 : 0; + case 5: return (cm3[0] & (1<<1)) ? 1 : 0; + case 6: return (cm3[0] & (1<<2)) ? 1 : 0; + case 7: return (cm3[0] & (1<<3)) ? 1 : 0; + default: + return (n > 7) ? 0 : -1; + } +} + +/*! \brief Check whether MS supports given cipher + * \param[in] cm Classmark data transmitted by MS, cannot be NULL + * \param[in] n Cipher number - A5/n + * \returns 1 if supported, 0 if unsupported, -1 on failures + * + * Implementation based on specifications from GSM 04.08 + * parts 10.5.1.6 and 10.5.1.7. + */ +static inline int ms_a5n_support(uint8_t *cm, unsigned n) { + return ((n < 4) ? ms_cm2_a5n_support(cm, n) : ms_cm3_a5n_support(cm, n)); +} + /* 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) { -- 1.9.1