libmsc/gsm_04_80.c: add msc_send_ussd_release_complete_cause()
According to GSM 04.80, section 2.5.1, Release complete message
may have an optional Cause IE. Let's add a new function, that
allows to specify cause location and value.
This function will be used by the upcoming changes.
Change-Id: I3b9e8e4f473d113d5b9e9e5d33f7914202077203
Depends Change-Id: (libosmocore) Ie3ac85fcef90a5e532334ba3482804d5305c88d7
diff --git a/include/osmocom/msc/gsm_04_80.h b/include/osmocom/msc/gsm_04_80.h
index 073794b..b786dcc 100644
--- a/include/osmocom/msc/gsm_04_80.h
+++ b/include/osmocom/msc/gsm_04_80.h
@@ -12,3 +12,6 @@
const char *text);
int msc_send_ussd_release_complete(struct ran_conn *conn,
uint8_t transaction_id);
+int msc_send_ussd_release_complete_cause(struct ran_conn *conn,
+ uint8_t transaction_id,
+ uint8_t cause_loc, uint8_t cause_val);
diff --git a/src/libmsc/gsm_04_80.c b/src/libmsc/gsm_04_80.c
index 502848f..e3547f4 100644
--- a/src/libmsc/gsm_04_80.c
+++ b/src/libmsc/gsm_04_80.c
@@ -86,3 +86,31 @@
return -1;
return msc_tx_dtap(conn, msg);
}
+
+int msc_send_ussd_release_complete_cause(struct ran_conn *conn,
+ uint8_t transaction_id,
+ uint8_t cause_loc, uint8_t cause_val)
+{
+ struct msgb *msg;
+ uint8_t *cause_ie;
+
+ msg = gsm0480_create_release_complete(transaction_id);
+ if (!msg)
+ return -1;
+
+ /* Encode cause IE (see GSM 04.08, section 10.5.4.11)
+ * with fixed length (2 bytes of TL, 2 bytes of payload).
+ * NOTE: we don't use gsm48_encode_cause() API because
+ * it wants gsm_mncc_cause struct from us. */
+ cause_ie = msgb_put(msg, 2 + 2);
+ cause_ie[0] = GSM48_IE_CAUSE;
+ cause_ie[1] = 2;
+
+ /* Coding standard defined for the GSM PLMNs,
+ * location and cause: as given by caller,
+ * no extension, no diagnostics. */
+ cause_ie[2] = (1 << 7) | (0x03 << 5) | (cause_loc & 0x0f);
+ cause_ie[3] = (1 << 7) | cause_val;
+
+ return msc_tx_dtap(conn, msg);
+}