gsm_utils: add enum osmo_rat_type, from osmo-msc enum ran_type

In the MSC, we have RAN types GERAN_A and UTRAN_IU, now we need a similar enum
in osmo-hlr's GSUP client.

Naming: in the MAP specifications, the RAN type is mostly called RAT type,
(Radio Access Network vs. Radio Access Technology?). Since GSUP is more about
MAP messages, I'm calling the enum osmo_rat_type.

Rationale: osmo-msc and osmo-sgsn want to tell the osmo-hlr which RAT a
subscriber is calling on. A subsequent patch will extend the GSUP protocol and
add a RAT types IE.

Change-Id: I659687aef7a4d67ca372a39fef31dee07aed7631

include/osmocom/gsm/gsm_utils.h

@@ -241,3 +241,16 @@ int gsm_7bit_decode_ussd(char *decoded, const uint8_t *user_data, uint8_t length
 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");
+
+enum osmo_rat_type {
+	OSMO_RAT_UNKNOWN = 0,
+	OSMO_RAT_GERAN_A,
+	OSMO_RAT_UTRAN_IU,
+
+	/* keep this last */
+	OSMO_RAT_COUNT
+};
+
+extern const struct value_string osmo_rat_type_names[];
+inline static const char *osmo_rat_type_name(enum osmo_rat_type val)
+{ return get_value_string(osmo_rat_type_names, val); }

src/gsm/gsm_utils.c

@@ -997,3 +997,11 @@ int gsm_7bit_encode_oct(uint8_t *result, const char *data, int *octets)
 	return gsm_7bit_encode_n(result, GSM_7BIT_LEGACY_MAX_BUFFER_SIZE,
 				 data, octets);
 }
+
+/* This is also used by osmo-hlr's db schema */
+const struct value_string osmo_rat_type_names[] = {
+	{ OSMO_RAT_UNKNOWN, "unknown" },
+	{ OSMO_RAT_GERAN_A, "GERAN-A" },
+	{ OSMO_RAT_UTRAN_IU, "UTRAN-Iu" },
+	{}
+};

src/gsm/libosmogsm.map

@@ -553,5 +553,7 @@ sgsap_sgs_cause_names;
 sgsap_ue_emm_mode_names;
 sgsap_ie_tlvdef;
 
+osmo_rat_type_names;
+
 local: *;
 };