diff options
Diffstat (limited to 'src/gsm/gsm48.c')
| -rw-r--r-- | src/gsm/gsm48.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c index 86d40d4c..4166c153 100644 --- a/src/gsm/gsm48.c +++ b/src/gsm/gsm48.c @@ -1160,4 +1160,130 @@ const struct value_string osmo_cm_service_type_names[] = { {} }; +bool osmo_gsm48_classmark1_is_r99(const struct gsm48_classmark1 *cm1) +{ + return cm1->rev_lev >= 2; +} + +bool osmo_gsm48_classmark2_is_r99(const struct gsm48_classmark2 *cm2, uint8_t cm2_len) +{ + if (!cm2_len) + return false; + return cm2->rev_lev >= 2; +} + +/*! Return true if any of Classmark 1 or Classmark 2 are present and indicate R99 capability. + * \param[in] cm Classmarks. + * \returns True if R99 or later, false if pre-R99 or no Classmarks are present. + */ +bool osmo_gsm48_classmark_is_r99(const struct osmo_gsm48_classmark *cm) +{ + if (cm->classmark1_set) + return osmo_gsm48_classmark1_is_r99(&cm->classmark1); + return osmo_gsm48_classmark2_is_r99(&cm->classmark2, cm->classmark2_len); +} + +/*! Return a string representation of A5 cipher algorithms indicated by Classmark 1, 2 and 3. + * \param[in] cm Classmarks. + * \returns A statically allocated string like "cm1{a5/1=supported} cm2{0x23= A5/2 A5/3} no-cm3" + */ +const char *osmo_gsm48_classmark_a5_name(const struct osmo_gsm48_classmark *cm) +{ + static char buf[128]; + char cm1[42] = "no-cm1"; + char cm2[42] = " no-cm2"; + char cm3[42] = " no-cm2"; + + if (cm->classmark1_set) + snprintf(cm1, sizeof(cm1), "cm1{a5/1=%s}", + cm->classmark1.a5_1 ? "not-supported":"supported" /* inverted logic */); + + if (cm->classmark2_len >= 3) + snprintf(cm2, sizeof(cm2), " cm2{0x%x=%s%s}", + cm->classmark2.a5_2 + (cm->classmark2.a5_3 << 1), + cm->classmark2.a5_2 ? " A5/2" : "", + cm->classmark2.a5_3 ? " A5/3" : ""); + + if (cm->classmark3_len >= 1) + snprintf(cm3, sizeof(cm3), " cm3{0x%x=%s%s%s%s}", + cm->classmark3[0], + cm->classmark3[0] & (1 << 0) ? " A5/4" : "", + cm->classmark3[0] & (1 << 1) ? " A5/5" : "", + cm->classmark3[0] & (1 << 2) ? " A5/6" : "", + cm->classmark3[0] & (1 << 3) ? " A5/7" : ""); + + snprintf(buf, sizeof(buf), "%s%s%s", cm1, cm2, cm3); + return buf; +} + +/*! Overwrite dst with the Classmark information present in src. + * Add an new Classmark and overwrite in dst what src has to offer, but where src has no Classmark information, leave + * dst unchanged. (For Classmark 2 and 3, dst will exactly match any non-zero Classmark length from src, hence may end + * up with a shorter Classmark after this call.) + * \param[out] dst The target Classmark storage to be updated. + * \param[in] src The new Classmark information to read from. + */ +void osmo_gsm48_classmark_update(struct osmo_gsm48_classmark *dst, const struct osmo_gsm48_classmark *src) +{ + if (src->classmark1_set) { + dst->classmark1 = src->classmark1; + dst->classmark1_set = true; + } + if (src->classmark2_len) { + dst->classmark2_len = src->classmark2_len; + dst->classmark2 = src->classmark2; + } + if (src->classmark3_len) { + dst->classmark3_len = src->classmark3_len; + memcpy(dst->classmark3, src->classmark3, OSMO_MIN(sizeof(dst->classmark3), src->classmark3_len)); + } +} + + +/*! Determine if the given Classmark (1/2/3) value permits a given A5/n cipher. + * \param[in] cm Classmarks. + * \param[in] a5 The N in A5/N for which to query whether support is indicated. + * \return 1 when the given A5/n is permitted, 0 when not (or a5 > 7), and negative if the respective MS Classmark is + * not known, where the negative number indicates the classmark type: -2 means Classmark 2 is not available. The + * idea is that when e.g. A5/3 is requested and the corresponding Classmark 3 is not available, that the caller + * can react by obtaining Classmark 3 and calling again once it is available. + */ +int osmo_gsm48_classmark_supports_a5(const struct osmo_gsm48_classmark *cm, uint8_t a5) +{ + switch (a5) { + case 0: + /* all phones must implement A5/0, see 3GPP TS 43.020 4.9 */ + return 1; + case 1: + /* 3GPP TS 43.020 4.9 requires A5/1 to be suppored by all phones and actually states: + * "The network shall not provide service to an MS which indicates that it does not + * support the ciphering algorithm A5/1.". However, let's be more tolerant based + * on policy here */ + /* See 3GPP TS 24.008 10.5.1.7 */ + if (!cm->classmark1_set) + return -1; + /* Inverted logic for this bit! */ + return cm->classmark1.a5_1 ? 0 : 1; + case 2: + /* See 3GPP TS 24.008 10.5.1.6 */ + if (cm->classmark2_len < 3) + return -2; + return cm->classmark2.a5_2 ? 1 : 0; + case 3: + if (cm->classmark2_len < 3) + return -2; + return cm->classmark2.a5_3 ? 1 : 0; + case 4: + case 5: + case 6: + case 7: + /* See 3GPP TS 24.008 10.5.1.7 */ + if (!cm->classmark3_len) + return -3; + return (cm->classmark3[0] & (1 << (a5-4))) ? 1 : 0; + default: + return 0; + } +} + /*! @} */ |