GSUP: add Message Class IE
osmo-msc and osmo-hlr have distinct subsystems handling incoming GSUP messages.
So far we decide entirely by message type which code path should handle a GSUP
message. Thus no GSUP message type may be re-used across subsystems.
If we add a GSUP message to indicate a routing error, it would have to be a
distinct message type for subscriber management, another one for SMS, another
one for USSD...
To allow introducing common message types, introduce a GSUP Message Class IE.
In the presence of this IE, GSUP handlers can trivially direct a received
message to the right code path. If it is missing, handlers can fall back to the
previous switch(message_type) method.
Change-Id: Ic397a9f2c4a7224e47cab944c72e75ca5592efef
diff --git a/include/osmocom/gsm/gsup.h b/include/osmocom/gsm/gsup.h
index 9a583aa..7f304a3 100644
--- a/include/osmocom/gsm/gsup.h
+++ b/include/osmocom/gsm/gsup.h
@@ -68,6 +68,7 @@
OSMO_GSUP_FREEZE_PTMSI_IE = 0x07,
OSMO_GSUP_MSISDN_IE = 0x08,
OSMO_GSUP_HLR_NUMBER_IE = 0x09,
+ OSMO_GSUP_MESSAGE_CLASS_IE = 0x0a,
OSMO_GSUP_PDP_CONTEXT_ID_IE = 0x10,
OSMO_GSUP_PDP_TYPE_IE = 0x11,
OSMO_GSUP_ACCESS_POINT_NAME_IE = 0x12,
@@ -229,6 +230,21 @@
size_t pdp_charg_enc_len;
};
+enum osmo_gsup_message_class {
+ OSMO_GSUP_MESSAGE_CLASS_UNSET = 0,
+ OSMO_GSUP_MESSAGE_CLASS_SUBSCRIBER_MANAGEMENT = 1,
+ OSMO_GSUP_MESSAGE_CLASS_SMS = 2,
+ OSMO_GSUP_MESSAGE_CLASS_USSD = 3,
+ OSMO_GSUP_MESSAGE_CLASS_INTER_MSC = 4,
+ /* Keep this as last entry with a value of max(enum osmo_gsup_message_class) + 1.
+ * This value shall serve as the size for an array to aid de-muxing all known GSUP classes. */
+ OSMO_GSUP_MESSAGE_CLASS_ARRAYSIZE
+};
+
+extern const struct value_string osmo_gsup_message_class_names[];
+static inline const char *osmo_gsup_message_class_name(enum osmo_gsup_message_class val)
+{ return get_value_string(osmo_gsup_message_class_names, val); }
+
/*! parsed/decoded GSUP protocol message */
struct osmo_gsup_message {
enum osmo_gsup_message_type message_type;
@@ -286,6 +302,11 @@
const uint8_t *imei_enc;
size_t imei_enc_len;
enum osmo_gsup_imei_result imei_result;
+
+ /*! Indicate the message class to trivially dispatch incoming GSUP messages to the right code paths.
+ * Inter-MSC messages are *required* to set a class = OSMO_GSUP_MESSAGE_CLASS_INTER_MSC. For older message classes, this may
+ * be omitted (for backwards compatibility only -- if in doubt, include it). */
+ enum osmo_gsup_message_class message_class;
};
int osmo_gsup_decode(const uint8_t *data, size_t data_len,