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authorNeels Hofmeyr <neels@hofmeyr.de>2019-01-16 16:53:26 +0100
committerNeels Hofmeyr <neels@hofmeyr.de>2019-01-29 00:59:32 +0100
commit7740d26d7e6a3ee963cafadae8fc6d0ef7e7d21b (patch)
tree80853135e78da11fe0318a719b564e94c33d62b5
parent0423b61aa8dd75b3141e13cf9276b8fa14ceb473 (diff)
add osmo_classmark_* API
osmo-bsc and osmo-msc implement identical Classmark structures. It makes sense to define once near the gsm48 protocol definitions. Also move along some generic Classmark API from osmo-msc. Change-Id: Ifd27bab0380f7ad0c44c719aa6c8bd62cf7b034c
-rw-r--r--include/osmocom/gsm/protocol/gsm_04_08.h16
-rw-r--r--src/gsm/gsm48.c126
-rw-r--r--src/gsm/libosmogsm.map7
3 files changed, 149 insertions, 0 deletions
diff --git a/include/osmocom/gsm/protocol/gsm_04_08.h b/include/osmocom/gsm/protocol/gsm_04_08.h
index 234fa79..fbd4fe6 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08.h
@@ -56,6 +56,22 @@ struct gsm48_classmark2 {
#endif
} __attribute__ ((packed));
+struct osmo_gsm48_classmark {
+ bool classmark1_set;
+ struct gsm48_classmark1 classmark1;
+ uint8_t classmark2_len;
+ struct gsm48_classmark2 classmark2;
+ uint8_t classmark3_len;
+ uint8_t classmark3[14]; /* if cm3 gets extended by spec, it will be truncated */
+};
+
+bool osmo_gsm48_classmark_is_r99(const struct osmo_gsm48_classmark *cm);
+bool osmo_gsm48_classmark1_is_r99(const struct gsm48_classmark1 *cm1);
+bool osmo_gsm48_classmark2_is_r99(const struct gsm48_classmark2 *cm2, uint8_t cm2_len);
+int osmo_gsm48_classmark_supports_a5(const struct osmo_gsm48_classmark *cm, uint8_t a5);
+const char *osmo_gsm48_classmark_a5_name(const struct osmo_gsm48_classmark *cm);
+void osmo_gsm48_classmark_update(struct osmo_gsm48_classmark *dst, const struct osmo_gsm48_classmark *src);
+
/* Chapter 10.5.2.1b.3 */
#if OSMO_IS_LITTLE_ENDIAN == 1
struct gsm48_range_1024 {
diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c
index 86d40d4..4166c15 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;
+ }
+}
+
/*! @} */
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index ea8c9be..3cfe6a7 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -580,5 +580,12 @@ osmo_rat_type_names;
osmo_lu_type_names;
osmo_cm_service_type_names;
+osmo_classmark_is_r99;
+osmo_classmark1_is_r99;
+osmo_classmark2_is_r99;
+osmo_classmark_supports_a5;
+osmo_classmark_a5_name;
+osmo_classmark_update;
+
local: *;
};