libmsc/gsm_09_11.c: forward SS/USSD messages to HLR over GSUP
In order to be able to support external SS/USSD gateway, we should
not terminate the GSM 04.80 messages at OsmoMSC. Instead, we need
to follow the GSM TS 09.11 specification, and forward all messages
unhandled by OsmoMSC to OsmoHLR over GSUP protocol.
This change implements forwarding of MO SS/USSD messages. The
forwarding assumes transcoding between GSM 04.80 messages and
GSUP messages. The payload of Facility IE is carried 'as is'.
As a side-effect, this will disable the osmo-msc internal handler
implementing the "*#100#" for obtaining the subscribers own phone
number. In order to re-gain this functionality, you will need a
modern osmo-hlr (Change-Id I1d09fab810a6bb9ab02904de72dbc9e8a414f9f9)
and the following line in your osmo-hlr.cfg:
hlr
ussd route prefix *#100# internal own-msisdn
TTCN-3 test case: I01de73aced6057328a121577a5a83bc2615fb2d4
Change-Id: Ide5f7e350b537db80cd8326fc59c8bf2e01cb68c
diff --git a/include/osmocom/msc/gsm_09_11.h b/include/osmocom/msc/gsm_09_11.h
index 4e7a5b6..5e689fb 100644
--- a/include/osmocom/msc/gsm_09_11.h
+++ b/include/osmocom/msc/gsm_09_11.h
@@ -1,5 +1,7 @@
#pragma once
#include <osmocom/core/msgb.h>
+#include <osmocom/gsm/gsup.h>
int gsm0911_rcv_nc_ss(struct gsm_subscriber_connection *conn, struct msgb *msg);
+int gsm0911_gsup_handler(struct vlr_subscr *vsub, struct osmo_gsup_message *gsup);