Use proper naming for GSM TS 09.11 implementation

During a long time, we had both file and symbol names, actually
related to Supplementary Services, with the 'ussd' abbreviation.
This is not absolutely wrong, but isn't correct at the same time.

USSD is a kind of Supplementary Services, this is only a part
of them. There are also 'structured' Supplementary Services,
which can be call related or call independent.

The "Signalling interworking for supplementary services" is
defined by GSM TS 09.11, and this is exactly what MSC should
implement. Let's use the specification number for naming, as
we do e.g. in the GSM 04.11 (SMS) implementation.

Change-Id: Ic1eaceddb58132318e4e941be542da34b8ebefe1

include/osmocom/msc/Makefile.am

@@ -9,6 +9,7 @@ noinst_HEADERS = \
 	gsm_04_11.h \
 	gsm_04_14.h \
 	gsm_04_80.h \
+	gsm_09_11.h \
 	gsm_data.h \
 	gsm_data_shared.h \
 	gsm_subscriber.h \
@@ -30,7 +31,6 @@ noinst_HEADERS = \
 	smpp.h \
 	sms_queue.h \
 	transaction.h \
-	ussd.h \
 	vlr.h \
 	vty.h \
 	$(NULL)

include/osmocom/msc/gsm_09_11.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <osmocom/core/msgb.h>
+
+int gsm0911_rcv_nc_ss(struct gsm_subscriber_connection *conn, struct msgb *msg);

include/osmocom/msc/ussd.h

@@ -1,5 +0,0 @@
-#pragma once
-
-#include <osmocom/core/msgb.h>
-
-int handle_rcv_ussd(struct gsm_subscriber_connection *conn, struct msgb *msg);

src/libmsc/Makefile.am

@@ -35,6 +35,7 @@ libmsc_a_SOURCES = \
 	gsm_04_11.c \
 	gsm_04_14.c \
 	gsm_04_80.c \
+	gsm_09_11.c \
 	gsm_subscriber.c \
 	mncc.c \
 	mncc_builtin.c \
@@ -44,7 +45,6 @@ libmsc_a_SOURCES = \
 	rrlp.c \
 	silent_call.c \
 	sms_queue.c \
-	ussd.c \
 	transaction.c \
 	osmo_msc.c \
 	ctrl_commands.c \

src/libmsc/gsm_04_08.c

@@ -42,9 +42,9 @@
 #include <osmocom/msc/gsm_04_08.h>
 #include <osmocom/msc/gsm_04_80.h>
 #include <osmocom/msc/gsm_04_14.h>
+#include <osmocom/msc/gsm_09_11.h>
 #include <osmocom/msc/signal.h>
 #include <osmocom/msc/transaction.h>
-#include <osmocom/msc/ussd.h>
 #include <osmocom/msc/silent_call.h>
 #include <osmocom/msc/osmo_msc.h>
 #include <osmocom/msc/mncc_int.h>
@@ -3524,7 +3524,7 @@ int gsm0408_dispatch(struct gsm_subscriber_connection *conn, struct msgb *msg)
 		rc = -ENOTSUP;
 		break;
 	case GSM48_PDISC_NC_SS:
-		rc = handle_rcv_ussd(conn, msg);
+		rc = gsm0911_rcv_nc_ss(conn, msg);
 		break;
 	case GSM48_PDISC_TEST:
 		rc = gsm0414_rcv_test(conn, msg);

src/libmsc/gsm_09_11.c

@@ -1,5 +1,3 @@
-/* Network-specific handling of mobile-originated USSDs. */
-
 /* (C) 2008-2009 by Harald Welte <laforge@gnumonks.org>
  * (C) 2008, 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
  * (C) 2009 by Mike Haben <michael.haben@btinternet.com>
@@ -21,8 +19,11 @@
  *
  */
 
-/* This module defines the network-specific handling of mobile-originated
-   USSD messages. */
+/**
+ * MSC-specific handling of call independent Supplementary
+ * Services messages (NC_SS) according to GSM TS 09.11
+ * "Signalling interworking for supplementary services".
+ */
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -58,8 +59,8 @@ static int send_own_number(struct gsm_subscriber_connection *conn,
 	return gsm0480_send_ussd_response(conn, response_string, req);
 }
 
-/* Entrypoint - handler function common to all mobile-originated USSDs */
-int handle_rcv_ussd(struct gsm_subscriber_connection *conn, struct msgb *msg)
+/* Entry point for call independent MO SS messages */
+int gsm0911_rcv_nc_ss(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
 	struct gsm_trans *trans;