Store identity of VLR/SGSN in UpdateLocation

The HLR must store the least-recently used VLR and SGSN identities in
its database to ensure subsequent mobile-terminated transactions can
be routed accordingly.

Change-Id: Ib2611421f3638eadc361787af801fffe9a34bd8a
Closes: OS#2796

doc/examples/osmo-hlr.cfg

@@ -17,3 +17,4 @@ ctrl
 hlr
  gsup
   bind ip 127.0.0.1
+ ussd route prefix *#100# internal own-msisdn

src/Makefile.am

@@ -32,12 +32,14 @@ noinst_HEADERS = \
 	ctrl.h \
 	hlr_vty.h \
 	hlr_vty_subscr.h \
+	hlr_ussd.h \
 	db_bootstrap.h \
 	$(NULL)
 
 bin_PROGRAMS = \
 	osmo-hlr \
 	osmo-hlr-db-tool \
+	osmo-euse-demo \
 	$(NULL)
 
 osmo_hlr_SOURCES = \
@@ -55,6 +57,7 @@ osmo_hlr_SOURCES = \
 	hlr_vty.c \
 	hlr_vty_subscr.c \
 	gsup_send.c \
+	hlr_ussd.c \
 	$(NULL)
 
 osmo_hlr_LDADD = \
@@ -96,6 +99,16 @@ db_test_LDADD = \
 	$(SQLITE3_LIBS) \
 	$(NULL)
 
+osmo_euse_demo_SOURCES = \
+	osmo-euse-demo.c \
+	$(NULL)
+
+osmo_euse_demo_LDADD = \
+	$(top_builddir)/src/gsupclient/libosmo-gsup-client.la \
+	$(LIBOSMOCORE_LIBS) \
+	$(LIBOSMOGSM_LIBS) \
+	$(NULL)
+
 BOOTSTRAP_SQL = $(top_srcdir)/sql/hlr.sql
 
 db_bootstrap.h: $(BOOTSTRAP_SQL) $(srcdir)/db_bootstrap.sed

src/gsup_router.c

@@ -23,6 +23,7 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/talloc.h>
 
+#include "logging.h"
 #include "gsup_server.h"
 
 struct gsup_route {
@@ -60,6 +61,8 @@ int gsup_route_add(struct osmo_gsup_conn *conn, const uint8_t *addr, size_t addr
 	if (!gr)
 		return -ENOMEM;
 
+	LOGP(DMAIN, LOGL_INFO, "Adding GSUP route for %s\n", addr);
+
 	gr->addr = talloc_memdup(gr, addr, addrlen);
 	gr->conn = conn;
 	llist_add_tail(&gr->list, &conn->server->routes);
@@ -75,6 +78,8 @@ int gsup_route_del_conn(struct osmo_gsup_conn *conn)
 
 	llist_for_each_entry_safe(gr, gr2, &conn->server->routes, list) {
 		if (gr->conn == conn) {
+			LOGP(DMAIN, LOGL_INFO, "Removing GSUP route for %s (GSUP disconnect)\n",
+			     gr->addr);
 			llist_del(&gr->list);
 			talloc_free(gr);
 			num_deleted++;

src/hlr.c

@@ -42,8 +42,9 @@
 #include "rand.h"
 #include "luop.h"
 #include "hlr_vty.h"
+#include "hlr_ussd.h"
 
-static struct hlr *g_hlr;
+struct hlr *g_hlr;
 static int quit = 0;
 
 /* Trigger 'Insert Subscriber Data' messages to all connected GSUP clients.
@@ -297,10 +298,19 @@ static int rx_upd_loc_req(struct osmo_gsup_conn *conn,
 	} else
 #endif
 	{
+		int rc;
+		uint8_t *addr;
+		rc = osmo_gsup_conn_ccm_get(conn, &addr, IPAC_IDTAG_SERNR);
+		if (rc <= 0) {
+			osmo_strlcpy(luop->subscr.imsi, gsup->imsi, sizeof(luop->subscr.imsi));
+			lu_op_tx_error(luop, GMM_CAUSE_NET_FAIL);
+			return 0;
+		}
 		/* TODO: Subscriber allowed to roam in PLMN? */
 		/* TODO: Update RoutingInfo */
 		/* TODO: Reset Flag MS Purged (cs/ps) */
 		/* TODO: Control_Tracing_HLR / Control_Tracing_HLR_with_SGSN */
+		db_subscr_lu(g_hlr->dbc, luop->subscr.id, (char *)addr, luop->is_ps);
 		lu_op_tx_insert_subscr_data(luop);
 	}
 	return 0;
@@ -402,6 +412,13 @@ static int read_cb(struct osmo_gsup_conn *conn, struct msgb *msg)
 		LOGP(DMAIN, LOGL_ERROR, "Deleting subscriber data for IMSI %s\n",
 		     gsup.imsi);
 		break;
+	case OSMO_GSUP_MSGT_PROC_SS_REQUEST:
+	case OSMO_GSUP_MSGT_PROC_SS_RESULT:
+		rx_proc_ss_req(conn, &gsup);
+		break;
+	case OSMO_GSUP_MSGT_PROC_SS_ERROR:
+		rx_proc_ss_error(conn, &gsup);
+		break;
 	case OSMO_GSUP_MSGT_INSERT_DATA_ERROR:
 	case OSMO_GSUP_MSGT_INSERT_DATA_RESULT:
 	case OSMO_GSUP_MSGT_LOCATION_CANCEL_ERROR:
@@ -559,6 +576,10 @@ int main(int argc, char **argv)
 	vty_info.tall_ctx = hlr_ctx;
 
 	g_hlr = talloc_zero(hlr_ctx, struct hlr);
+	INIT_LLIST_HEAD(&g_hlr->euse_list);
+	INIT_LLIST_HEAD(&g_hlr->iuse_list);
+	INIT_LLIST_HEAD(&g_hlr->ss_sessions);
+	INIT_LLIST_HEAD(&g_hlr->ussd_routes);
 
 	rc = osmo_init_logging2(hlr_ctx, &hlr_log_info);
 	if (rc < 0) {

src/hlr.h

@@ -23,6 +23,9 @@
 #pragma once
 
 #include <stdbool.h>
+#include <osmocom/core/linuxlist.h>
+
+struct hlr_euse;
 
 struct hlr {
 	/* GSUP server pointer */
@@ -37,8 +40,18 @@ struct hlr {
 
 	/* Local bind addr */
 	char *gsup_bind_addr;
+
+	struct llist_head euse_list;
+	struct hlr_euse *euse_default;
+	struct llist_head iuse_list;
+
+	struct llist_head ussd_routes;
+
+	struct llist_head ss_sessions;
 };
 
+extern struct hlr *g_hlr;
+
 struct hlr_subscriber;
 
 void osmo_hlr_subscriber_update_notify(struct hlr_subscriber *subscr);

src/hlr_ussd.c

@@ -0,0 +1,565 @@
+/* OsmoHLR SS/USSD implementation */
+
+/* (C) 2018 Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/gsm/gsup.h>
+#include <osmocom/gsm/gsm0480.h>
+#include <osmocom/gsm/protocol/gsm_04_80.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+
+#include "hlr.h"
+#include "hlr_ussd.h"
+#include "gsup_server.h"
+#include "gsup_router.h"
+#include "logging.h"
+
+/***********************************************************************
+ * core data structures expressing config from VTY
+ ***********************************************************************/
+
+struct hlr_euse *euse_find(struct hlr *hlr, const char *name)
+{
+	struct hlr_euse *euse;
+
+	llist_for_each_entry(euse, &hlr->euse_list, list) {
+		if (!strcmp(euse->name, name))
+			return euse;
+	}
+	return NULL;
+}
+
+struct hlr_euse *euse_alloc(struct hlr *hlr, const char *name)
+{
+	struct hlr_euse *euse = euse_find(hlr, name);
+	if (euse)
+		return NULL;
+
+	euse = talloc_zero(hlr, struct hlr_euse);
+	euse->name = talloc_strdup(euse, name);
+	euse->hlr = hlr;
+	llist_add_tail(&euse->list, &hlr->euse_list);
+
+	return euse;
+}
+
+void euse_del(struct hlr_euse *euse)
+{
+	llist_del(&euse->list);
+	talloc_free(euse);
+}
+
+
+struct hlr_ussd_route *ussd_route_find_prefix(struct hlr *hlr, const char *prefix)
+{
+	struct hlr_ussd_route *rt;
+
+	llist_for_each_entry(rt, &hlr->ussd_routes, list) {
+		if (!strcmp(rt->prefix, prefix))
+			return rt;
+	}
+	return NULL;
+}
+
+struct hlr_ussd_route *ussd_route_prefix_alloc_int(struct hlr *hlr, const char *prefix,
+						   const struct hlr_iuse *iuse)
+{
+	struct hlr_ussd_route *rt;
+
+	if (ussd_route_find_prefix(hlr, prefix))
+		return NULL;
+
+	rt = talloc_zero(hlr, struct hlr_ussd_route);
+	rt->prefix = talloc_strdup(rt, prefix);
+	rt->u.iuse = iuse;
+	llist_add_tail(&rt->list, &hlr->ussd_routes);
+
+	return rt;
+}
+
+struct hlr_ussd_route *ussd_route_prefix_alloc_ext(struct hlr *hlr, const char *prefix,
+						   struct hlr_euse *euse)
+{
+	struct hlr_ussd_route *rt;
+
+	if (ussd_route_find_prefix(hlr, prefix))
+		return NULL;
+
+	rt = talloc_zero(hlr, struct hlr_ussd_route);
+	rt->prefix = talloc_strdup(rt, prefix);
+	rt->is_external = true;
+	rt->u.euse = euse;
+	llist_add_tail(&rt->list, &hlr->ussd_routes);
+
+	return rt;
+}
+
+void ussd_route_del(struct hlr_ussd_route *rt)
+{
+	llist_del(&rt->list);
+	talloc_free(rt);
+}
+
+static struct hlr_ussd_route *ussd_route_lookup_7bit(struct hlr *hlr, const char *ussd_code)
+{
+	struct hlr_ussd_route *rt;
+	llist_for_each_entry(rt, &hlr->ussd_routes, list) {
+		if (!strncmp(ussd_code, rt->prefix, strlen(rt->prefix))) {
+			LOGP(DSS, LOGL_DEBUG, "Found EUSE %s (prefix %s) for USSD Code '%s'\n",
+				rt->u.euse->name, rt->prefix, ussd_code);
+			return rt;
+		}
+	}
+
+	LOGP(DSS, LOGL_DEBUG, "Could not find Route for USSD Code '%s'\n", ussd_code);
+	return NULL;
+}
+
+/***********************************************************************
+ * handling functions for individual GSUP messages
+ ***********************************************************************/
+
+#define LOGPSS(ss, lvl, fmt, args...) \
+	LOGP(DSS, lvl, "%s/0x%08x: " fmt, (ss)->imsi, (ss)->session_id, ## args)
+
+struct ss_session {
+	/* link us to hlr->ss_sessions */
+	struct llist_head list;
+	/* imsi of this session */
+	char imsi[GSM23003_IMSI_MAX_DIGITS+2];
+	/* ID of this session (unique per IMSI) */
+	uint32_t session_id;
+	/* state of the session */
+	enum osmo_gsup_session_state state;
+	/* time-out when we will delete the session */
+	struct osmo_timer_list timeout;
+
+	/* is this USSD for an external handler (EUSE): true */
+	bool is_external;
+	union {
+		/* external USSD Entity responsible for this session */
+		struct hlr_euse *euse;
+		/* internal USSD Entity responsible for this session */
+		const struct hlr_iuse *iuse;
+	} u;
+
+	/* we don't keep a pointer to the osmo_gsup_{route,conn} towards the MSC/VLR here,
+	 * as this might change during inter-VLR hand-over, and we simply look-up the serving MSC/VLR
+	 * every time we receive an USSD component from the EUSE */
+};
+
+struct ss_session *ss_session_find(struct hlr *hlr, const char *imsi, uint32_t session_id)
+{
+	struct ss_session *ss;
+	llist_for_each_entry(ss, &hlr->ss_sessions, list) {
+		if (!strcmp(ss->imsi, imsi) && ss->session_id == session_id)
+			return ss;
+	}
+	return NULL;
+}
+
+void ss_session_free(struct ss_session *ss)
+{
+	osmo_timer_del(&ss->timeout);
+	llist_del(&ss->list);
+	talloc_free(ss);
+}
+
+static void ss_session_timeout(void *data)
+{
+	struct ss_session *ss = data;
+
+	LOGPSS(ss, LOGL_NOTICE, "SS Session Timeout, destroying\n");
+	/* FIXME: should we send a ReturnError component to the MS? */
+	ss_session_free(ss);
+}
+
+struct ss_session *ss_session_alloc(struct hlr *hlr, const char *imsi, uint32_t session_id)
+{
+	struct ss_session *ss;
+
+	OSMO_ASSERT(!ss_session_find(hlr, imsi, session_id));
+
+	ss = talloc_zero(hlr, struct ss_session);
+	OSMO_ASSERT(ss);
+
+	OSMO_STRLCPY_ARRAY(ss->imsi, imsi);
+	ss->session_id = session_id;
+	osmo_timer_setup(&ss->timeout, ss_session_timeout, ss);
+	/* NOTE: The timeout is currently global and not refreshed with subsequent messages
+	 * within the SS/USSD session.  So 30s after the initial SS message, the session will
+	 * timeout! */
+	osmo_timer_schedule(&ss->timeout, 30, 0);
+
+	llist_add_tail(&ss->list, &hlr->ss_sessions);
+	return ss;
+}
+
+/***********************************************************************
+ * handling functions for encoding SS messages + wrapping them in GSUP
+ ***********************************************************************/
+
+static int ss_tx_to_ms(struct ss_session *ss, enum osmo_gsup_message_type gsup_msg_type,
+			bool final, struct msgb *ss_msg)
+
+{
+	struct osmo_gsup_message resp = {0};
+	struct msgb *resp_msg;
+
+	resp.message_type = gsup_msg_type;
+	OSMO_STRLCPY_ARRAY(resp.imsi, ss->imsi);
+	if (final)
+		resp.session_state = OSMO_GSUP_SESSION_STATE_END;
+	else
+		resp.session_state = OSMO_GSUP_SESSION_STATE_CONTINUE;
+	resp.session_id = ss->session_id;
+	if (ss_msg) {
+		resp.ss_info = msgb_data(ss_msg);
+		resp.ss_info_len = msgb_length(ss_msg);
+	}
+
+	resp_msg = gsm0480_msgb_alloc_name(__func__);
+	OSMO_ASSERT(resp_msg);
+	osmo_gsup_encode(resp_msg, &resp);
+	msgb_free(ss_msg);
+
+	/* FIXME: resolve this based on the database vlr_addr */
+	return osmo_gsup_addr_send(g_hlr->gs, (uint8_t *)"MSC-00-00-00-00-00-00", 22, resp_msg);
+}
+
+#if 0
+static int ss_tx_reject(struct ss_session *ss, int invoke_id, uint8_t problem_tag,
+			uint8_t problem_code)
+{
+	struct msgb *msg = gsm0480_gen_reject(invoke_id, problem_tag, problem_code);
+	LOGPSS(ss, LOGL_NOTICE, "Tx Reject(%u, 0x%02x, 0x%02x)\n", invoke_id,
+		problem_tag, problem_code);
+	OSMO_ASSERT(msg);
+	return ss_tx_to_ms(ss, OSMO_GSUP_MSGT_PROC_SS_RESULT, true, msg);
+}
+#endif
+
+static int ss_tx_error(struct ss_session *ss, uint8_t invoke_id, uint8_t error_code)
+{
+	struct msgb *msg = gsm0480_gen_return_error(invoke_id, error_code);
+	LOGPSS(ss, LOGL_NOTICE, "Tx ReturnError(%u, 0x%02x)\n", invoke_id, error_code);
+	OSMO_ASSERT(msg);
+	return ss_tx_to_ms(ss, OSMO_GSUP_MSGT_PROC_SS_RESULT, true, msg);
+}
+
+static int ss_tx_ussd_7bit(struct ss_session *ss, bool final, uint8_t invoke_id, const char *text)
+{
+	struct msgb *msg = gsm0480_gen_ussd_resp_7bit(invoke_id, text);
+	LOGPSS(ss, LOGL_INFO, "Tx USSD '%s'\n", text);
+	OSMO_ASSERT(msg);
+	return ss_tx_to_ms(ss, OSMO_GSUP_MSGT_PROC_SS_RESULT, final, msg);
+}
+
+/***********************************************************************
+ * Internal USSD Handlers
+ ***********************************************************************/
+
+#include "db.h"
+
+static int handle_ussd_own_msisdn(struct osmo_gsup_conn *conn, struct ss_session *ss,
+				  const struct osmo_gsup_message *gsup, const struct ss_request *req)
+{
+	struct hlr_subscriber subscr;
+	char buf[GSM0480_USSD_7BIT_STRING_LEN+1];
+	int rc;
+
+	rc = db_subscr_get_by_imsi(g_hlr->dbc, ss->imsi, &subscr);
+	switch (rc) {
+	case 0:
+		if (strlen(subscr.msisdn) == 0)
+			snprintf(buf, sizeof(buf), "You have no MSISDN!");
+		else
+			snprintf(buf, sizeof(buf), "Your extension is %s\r", subscr.msisdn);
+		ss_tx_ussd_7bit(ss, true, req->invoke_id, buf);
+		break;
+	case -ENOENT:
+		ss_tx_error(ss, true, GSM0480_ERR_CODE_UNKNOWN_SUBSCRIBER);
+		break;
+	case -EIO:
+	default:
+		ss_tx_error(ss, true, GSM0480_ERR_CODE_SYSTEM_FAILURE);
+		break;
+	}
+	return 0;
+}
+
+static int handle_ussd_own_imsi(struct osmo_gsup_conn *conn, struct ss_session *ss,
+				const struct osmo_gsup_message *gsup, const struct ss_request *req)
+{
+	char buf[GSM0480_USSD_7BIT_STRING_LEN+1];
+	snprintf(buf, sizeof(buf), "Your IMSI is %s!\n", ss->imsi);
+	ss_tx_ussd_7bit(ss, true, req->invoke_id, buf);
+	return 0;
+}
+
+
+static const struct hlr_iuse hlr_iuses[] = {
+	{
+		.name = "own-msisdn",
+		.handle_ussd = handle_ussd_own_msisdn,
+	},
+	{
+		.name = "own-imsi",
+		.handle_ussd = handle_ussd_own_imsi,
+	},
+};
+
+const struct hlr_iuse *iuse_find(const char *name)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(hlr_iuses); i++) {
+		const struct hlr_iuse *iuse = &hlr_iuses[i];
+		if (!strcmp(name, iuse->name))
+			return iuse;
+	}
+	return NULL;
+}
+
+
+/***********************************************************************
+ * handling functions for individual GSUP messages
+ ***********************************************************************/
+
+static bool ss_op_is_ussd(uint8_t opcode)
+{
+	switch (opcode) {
+	case GSM0480_OP_CODE_PROCESS_USS_DATA:
+	case GSM0480_OP_CODE_PROCESS_USS_REQ:
+	case GSM0480_OP_CODE_USS_REQUEST:
+	case GSM0480_OP_CODE_USS_NOTIFY:
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* is this GSUP connection an EUSE (true) or not (false)? */
+static bool conn_is_euse(struct osmo_gsup_conn *conn)
+{
+	int rc;
+	uint8_t *addr;
+
+	rc = osmo_gsup_conn_ccm_get(conn, &addr, IPAC_IDTAG_SERNR);
+	if (rc <= 5)
+		return false;
+	if (!strncmp((char *)addr, "EUSE-", 5))
+		return true;
+	else
+		return false;
+}
+
+static struct hlr_euse *euse_by_conn(struct osmo_gsup_conn *conn)
+{
+	int rc;
+	char *addr;
+	struct hlr *hlr = conn->server->priv;
+
+	rc = osmo_gsup_conn_ccm_get(conn, (uint8_t **) &addr, IPAC_IDTAG_SERNR);
+	if (rc <= 5)
+		return NULL;
+	if (strncmp(addr, "EUSE-", 5))
+		return NULL;
+
+	return euse_find(hlr, addr+5);
+}
+
+static int handle_ss(struct ss_session *ss, const struct osmo_gsup_message *gsup,
+			const struct ss_request *req)
+{
+	uint8_t comp_type = gsup->ss_info[0];
+
+	LOGPSS(ss, LOGL_INFO, "SS CompType=%s, OpCode=%s\n",
+		gsm0480_comp_type_name(comp_type), gsm0480_op_code_name(req->opcode));
+	/* FIXME */
+	return 0;
+}
+
+/* Handle a USSD GSUP message for a given SS Session received from VLR or EUSE */
+static int handle_ussd(struct osmo_gsup_conn *conn, struct ss_session *ss,
+			const struct osmo_gsup_message *gsup, const struct ss_request *req)
+{
+	uint8_t comp_type = gsup->ss_info[0];
+	struct msgb *msg_out;
+	bool is_euse_originated = conn_is_euse(conn);
+
+	LOGPSS(ss, LOGL_INFO, "USSD CompType=%s, OpCode=%s '%s'\n",
+		gsm0480_comp_type_name(comp_type), gsm0480_op_code_name(req->opcode),
+		req->ussd_text);
+
+	if ((ss->is_external && !ss->u.euse) || !ss->u.iuse) {
+		LOGPSS(ss, LOGL_NOTICE, "USSD for unknown code '%s'\n", req->ussd_text);
+		ss_tx_error(ss, req->invoke_id, GSM0480_ERR_CODE_SS_NOT_AVAILABLE);
+		return 0;
+	}
+
+	if (is_euse_originated) {
+		msg_out = msgb_alloc_headroom(1024+16, 16, "GSUP USSD FW");
+		OSMO_ASSERT(msg_out);
+		/* Received from EUSE, Forward to VLR */
+		osmo_gsup_encode(msg_out, gsup);
+		/* FIXME: resolve this based on the database vlr_addr */
+		osmo_gsup_addr_send(conn->server, (uint8_t *)"MSC-00-00-00-00-00-00", 22, msg_out);
+	} else {
+		/* Received from VLR (MS) */
+		if (ss->is_external) {
+			/* Forward to EUSE */
+			char addr[128];
+			strcpy(addr, "EUSE-");
+			osmo_strlcpy(addr+5, ss->u.euse->name, sizeof(addr)-5);
+			conn = gsup_route_find(conn->server, (uint8_t *)addr, strlen(addr)+1);
+			if (!conn) {
+				LOGPSS(ss, LOGL_ERROR, "Cannot find conn for EUSE %s\n", addr);
+				ss_tx_error(ss, req->invoke_id, GSM0480_ERR_CODE_SYSTEM_FAILURE);
+			} else {
+				msg_out = msgb_alloc_headroom(1024+16, 16, "GSUP USSD FW");
+				OSMO_ASSERT(msg_out);
+				osmo_gsup_encode(msg_out, gsup);
+				osmo_gsup_conn_send(conn, msg_out);
+			}
+		} else {
+			/* Handle internally */
+			ss->u.iuse->handle_ussd(conn, ss, gsup, req);
+		}
+	}
+
+	return 0;
+}
+
+
+/* this function is called for any SS_REQ/SS_RESP messages from both the MSC/VLR side as well
+ * as from the EUSE side */
+int rx_proc_ss_req(struct osmo_gsup_conn *conn, const struct osmo_gsup_message *gsup)
+{
+	struct hlr *hlr = conn->server->priv;
+	struct ss_session *ss;
+	struct ss_request req = {0};
+
+	LOGP(DSS, LOGL_DEBUG, "%s/0x%08x: Process SS (%s)\n", gsup->imsi, gsup->session_id,
+		osmo_gsup_session_state_name(gsup->session_state));
+
+	/* decode and find out what kind of SS message it is */
+	if (gsup->ss_info && gsup->ss_info_len) {
+		if (gsm0480_parse_facility_ie(gsup->ss_info, gsup->ss_info_len, &req)) {
+			LOGP(DSS, LOGL_ERROR, "%s/0x%082x: Unable to parse SS request: %s\n",
+				gsup->imsi, gsup->session_id,
+				osmo_hexdump(gsup->ss_info, gsup->ss_info_len));
+			/* FIXME: Send a Reject component? */
+			goto out_err;
+		}
+	}
+
+	switch (gsup->session_state) {
+	case OSMO_GSUP_SESSION_STATE_BEGIN:
+		/* Check for overlapping Session ID usage */
+		if (ss_session_find(hlr, gsup->imsi, gsup->session_id)) {
+			LOGP(DSS, LOGL_ERROR, "%s/0x%08x: BEGIN with non-unique session ID!\n",
+				gsup->imsi, gsup->session_id);
+			goto out_err;
+		}
+		ss = ss_session_alloc(hlr, gsup->imsi, gsup->session_id);
+		if (!ss) {
+			LOGP(DSS, LOGL_ERROR, "%s/0x%08x: Unable to allocate SS session\n",
+				gsup->imsi, gsup->session_id);
+			goto out_err;
+		}
+		if (ss_op_is_ussd(req.opcode)) {
+			if (conn_is_euse(conn)) {
+				/* EUSE->VLR: MT USSD. EUSE is known ('conn'), VLR is to be resolved */
+				ss->u.euse = euse_by_conn(conn);
+			} else {
+				/* VLR->EUSE: MO USSD. VLR is known ('conn'), EUSE is to be resolved */
+				struct hlr_ussd_route *rt;
+				rt = ussd_route_lookup_7bit(hlr, (const char *) req.ussd_text);
+				if (rt) {
+					if (rt->is_external) {
+						ss->is_external = true;
+						ss->u.euse = rt->u.euse;
+					} else if (rt) {
+						ss->is_external = false;
+						ss->u.iuse = rt->u.iuse;
+					}
+				}
+			}
+			/* dispatch unstructured SS to routing */
+			handle_ussd(conn, ss, gsup, &req);
+		} else {
+			/* dispatch non-call SS to internal code */
+			handle_ss(ss, gsup, &req);
+		}
+		break;
+	case OSMO_GSUP_SESSION_STATE_CONTINUE:
+		ss = ss_session_find(hlr, gsup->imsi, gsup->session_id);
+		if (!ss) {
+			LOGP(DSS, LOGL_ERROR, "%s/0x%08x: CONTINUE for unknown SS session\n",
+				gsup->imsi, gsup->session_id);
+			goto out_err;
+		}
+		if (ss_op_is_ussd(req.opcode)) {
+			/* dispatch unstructured SS to routing */
+			handle_ussd(conn, ss, gsup, &req);
+		} else {
+			/* dispatch non-call SS to internal code */
+			handle_ss(ss, gsup, &req);
+		}
+		break;
+	case OSMO_GSUP_SESSION_STATE_END:
+		ss = ss_session_find(hlr, gsup->imsi, gsup->session_id);
+		if (!ss) {
+			LOGP(DSS, LOGL_ERROR, "%s/0x%08x: END for unknown SS session\n",
+				gsup->imsi, gsup->session_id);
+			goto out_err;
+		}
+		if (ss_op_is_ussd(req.opcode)) {
+			/* dispatch unstructured SS to routing */
+			handle_ussd(conn, ss, gsup, &req);
+		} else {
+			/* dispatch non-call SS to internal code */
+			handle_ss(ss, gsup, &req);
+		}
+		ss_session_free(ss);
+		break;
+	default:
+		LOGP(DSS, LOGL_ERROR, "%s/0x%08x: Unknown SS State %d\n", gsup->imsi,
+			gsup->session_id, gsup->session_state);
+		goto out_err;
+	}
+
+	return 0;
+
+out_err:
+	return 0;
+}
+
+int rx_proc_ss_error(struct osmo_gsup_conn *conn, const struct osmo_gsup_message *gsup)
+{
+	LOGP(DSS, LOGL_NOTICE, "%s/0x%08x: Process SS ERROR (%s)\n", gsup->imsi, gsup->session_id,
+		osmo_gsup_session_state_name(gsup->session_state));
+	return 0;
+}

src/hlr_ussd.h

@@ -0,0 +1,57 @@
+#include <stdint.h>
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/gsm/gsup.h>
+#include "gsup_server.h"
+
+struct osmo_gsup_conn;
+
+struct hlr_ussd_route {
+	/* g_hlr.routes */
+	struct llist_head list;
+	const char *prefix;
+	bool is_external;
+	union {
+		struct hlr_euse *euse;
+		const struct hlr_iuse *iuse;
+	} u;
+};
+
+struct hlr_euse {
+	/* list in the per-hlr list of EUSEs */
+	struct llist_head list;
+	struct hlr *hlr;
+	/* name (must match the IPA ID tag) */
+	const char *name;
+	/* human-readable description */
+	const char *description;
+
+	/* GSUP connection to the EUSE, if any */
+	struct osmo_gsup_conn *conn;
+};
+
+struct hlr_euse *euse_find(struct hlr *hlr, const char *name);
+struct hlr_euse *euse_alloc(struct hlr *hlr, const char *name);
+void euse_del(struct hlr_euse *euse);
+
+const struct hlr_iuse *iuse_find(const char *name);
+
+struct hlr_ussd_route *ussd_route_find_prefix(struct hlr *hlr, const char *prefix);
+struct hlr_ussd_route *ussd_route_prefix_alloc_int(struct hlr *hlr, const char *prefix,
+						   const struct hlr_iuse *iuse);
+struct hlr_ussd_route *ussd_route_prefix_alloc_ext(struct hlr *hlr, const char *prefix,
+						   struct hlr_euse *euse);
+void ussd_route_del(struct hlr_ussd_route *rt);
+
+int rx_proc_ss_req(struct osmo_gsup_conn *conn, const struct osmo_gsup_message *gsup);
+int rx_proc_ss_error(struct osmo_gsup_conn *conn, const struct osmo_gsup_message *gsup);
+
+struct ss_session;
+struct ss_request;
+
+/* Internal USSD Handler */
+struct hlr_iuse {
+	const char *name;
+	/* call-back to be called for any incoming USSD messages for this IUSE */
+	int (*handle_ussd)(struct osmo_gsup_conn *conn, struct ss_session *ss,
+			   const struct osmo_gsup_message *gsup, const struct ss_request *req);
+};

src/hlr_vty.c

@@ -6,6 +6,10 @@
  *
  * All Rights Reserved
  *
+ * (C) 2018 Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as published by
  * the Free Software Foundation; either version 3 of the License, or
@@ -28,12 +32,11 @@
 #include <osmocom/vty/misc.h>
 #include <osmocom/abis/ipa.h>
 
+#include "hlr.h"
 #include "hlr_vty.h"
 #include "hlr_vty_subscr.h"
 #include "gsup_server.h"
 
-static struct hlr *g_hlr = NULL;
-
 struct cmd_node hlr_node = {
 	HLR_NODE,
 	"%s(config-hlr)# ",
@@ -119,12 +122,180 @@ DEFUN(cfg_hlr_gsup_bind_ip,
 	return CMD_SUCCESS;
 }
 
+/***********************************************************************
+ * USSD Entity
+ ***********************************************************************/
+
+#include "hlr_ussd.h"
+
+#define USSD_STR "USSD Configuration\n"
+#define UROUTE_STR "Routing Configuration\n"
+#define PREFIX_STR "Prefix-Matching Route\n" "USSD Prefix\n"
+
+#define INT_CHOICE "(own-msisdn|own-imsi)"
+#define INT_STR "Internal USSD Handler\n" \
+		"Respond with subscribers' own MSISDN\n" \
+		"Respond with subscribers' own IMSI\n"
+
+#define EXT_STR "External USSD Handler\n" \
+		"Name of External USSD Handler (IPA CCM ID)\n"
+
+DEFUN(cfg_ussd_route_pfx_int, cfg_ussd_route_pfx_int_cmd,
+	"ussd route prefix PREFIX internal " INT_CHOICE,
+	USSD_STR UROUTE_STR PREFIX_STR INT_STR)
+{
+	const struct hlr_iuse *iuse = iuse_find(argv[1]);
+	struct hlr_ussd_route *rt = ussd_route_find_prefix(g_hlr, argv[0]);
+	if (rt) {
+		vty_out(vty, "%% Cannot add [another?] route for prefix %s%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	ussd_route_prefix_alloc_int(g_hlr, argv[0], iuse);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_ussd_route_pfx_ext, cfg_ussd_route_pfx_ext_cmd,
+	"ussd route prefix PREFIX external EUSE",
+	USSD_STR UROUTE_STR PREFIX_STR EXT_STR)
+{
+	struct hlr_euse *euse = euse_find(g_hlr, argv[1]);
+	struct hlr_ussd_route *rt = ussd_route_find_prefix(g_hlr, argv[0]);
+	if (rt) {
+		vty_out(vty, "%% Cannot add [another?] route for prefix %s%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	if (!euse) {
+		vty_out(vty, "%% Cannot find euse '%s'%s", argv[1], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	ussd_route_prefix_alloc_ext(g_hlr, argv[0], euse);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_ussd_no_route_pfx, cfg_ussd_no_route_pfx_cmd,
+	"no ussd route prefix PREFIX",
+	NO_STR USSD_STR UROUTE_STR PREFIX_STR)
+{
+	struct hlr_ussd_route *rt = ussd_route_find_prefix(g_hlr, argv[0]);
+	if (!rt) {
+		vty_out(vty, "%% Cannot find route for prefix %s%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	ussd_route_del(rt);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_ussd_defaultroute, cfg_ussd_defaultroute_cmd,
+	"ussd default-route external EUSE",
+	USSD_STR "Configure default-route for all USSD to unknown destinations\n"
+	EXT_STR)
+{
+	struct hlr_euse *euse = euse_find(g_hlr, argv[0]);
+
+	if (g_hlr->euse_default != euse) {
+		vty_out(vty, "Switching default route from %s to %s%s",
+			g_hlr->euse_default->name, euse->name, VTY_NEWLINE);
+		g_hlr->euse_default = euse;
+	}
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_ussd_no_defaultroute, cfg_ussd_no_defaultroute_cmd,
+	"no ussd default-route",
+	NO_STR USSD_STR "Remove the default-route for all USSD to unknown destinations\n")
+{
+	g_hlr->euse_default = NULL;
+
+	return CMD_SUCCESS;
+}
+
+struct cmd_node euse_node = {
+	EUSE_NODE,
+	"%s(config-hlr-euse)# ",
+	1,
+};
+
+DEFUN(cfg_euse, cfg_euse_cmd,
+	"euse NAME",
+	"Configure a particular External USSD Entity\n"
+	"Alphanumeric name of the External USSD Entity\n")
+{
+	struct hlr_euse *euse;
+	const char *id = argv[0];
+
+	euse = euse_find(g_hlr, id);
+	if (!euse) {
+		euse = euse_alloc(g_hlr, id);
+		if (!euse)
+			return CMD_WARNING;
+	}
+	vty->index = euse;
+	vty->index_sub = &euse->description;
+	vty->node = EUSE_NODE;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_no_euse, cfg_no_euse_cmd,
+	"no euse NAME",
+	NO_STR "Remove a particular External USSD Entity\n"
+	"Alphanumeric name of the External USSD Entity\n")
+{
+	struct hlr_euse *euse = euse_find(g_hlr, argv[0]);
+	if (!euse) {
+		vty_out(vty, "%% Cannot remove non-existant EUSE %s%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	if (g_hlr->euse_default == euse) {
+		vty_out(vty, "%% Cannot remove EUSE %s, it is the default route%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	euse_del(euse);
+	return CMD_SUCCESS;
+}
+
+static void dump_one_euse(struct vty *vty, struct hlr_euse *euse)
+{
+	vty_out(vty, " euse %s%s", euse->name, VTY_NEWLINE);
+
+	if (g_hlr->euse_default == euse)
+		vty_out(vty, "  default-route%s", VTY_NEWLINE);
+}
+
+static int config_write_euse(struct vty *vty)
+{
+	struct hlr_euse *euse;
+	struct hlr_ussd_route *rt;
+
+	llist_for_each_entry(euse, &g_hlr->euse_list, list)
+		dump_one_euse(vty, euse);
+
+	llist_for_each_entry(rt, &g_hlr->ussd_routes, list) {
+		vty_out(vty, " ussd route prefix %s %s %s%s", rt->prefix,
+			rt->is_external ? "external" : "internal",
+			rt->is_external ? rt->u.euse->name : rt->u.iuse->name,
+			VTY_NEWLINE);
+	}
+
+	return 0;
+}
+
+/***********************************************************************
+ * Common Code
+ ***********************************************************************/
+
 int hlr_vty_go_parent(struct vty *vty)
 {
 	switch (vty->node) {
 	case GSUP_NODE:
+	case EUSE_NODE:
 		vty->node = HLR_NODE;
 		vty->index = NULL;
+		vty->index_sub = NULL;
 		break;
 	default:
 	case HLR_NODE:
@@ -154,8 +325,6 @@ int hlr_vty_is_config_node(struct vty *vty, int node)
 
 void hlr_vty_init(struct hlr *hlr, const struct log_info *cat)
 {
-	g_hlr = hlr;
-
 	logging_vty_add_cmds(cat);
 	osmo_talloc_vty_add_cmds();
 
@@ -169,5 +338,14 @@ void hlr_vty_init(struct hlr *hlr, const struct log_info *cat)
 
 	install_element(GSUP_NODE, &cfg_hlr_gsup_bind_ip_cmd);
 
+	install_element(HLR_NODE, &cfg_euse_cmd);
+	install_element(HLR_NODE, &cfg_no_euse_cmd);
+	install_node(&euse_node, config_write_euse);
+	install_element(HLR_NODE, &cfg_ussd_route_pfx_int_cmd);
+	install_element(HLR_NODE, &cfg_ussd_route_pfx_ext_cmd);
+	install_element(HLR_NODE, &cfg_ussd_no_route_pfx_cmd);
+	install_element(HLR_NODE, &cfg_ussd_defaultroute_cmd);
+	install_element(HLR_NODE, &cfg_ussd_no_defaultroute_cmd);
+
 	hlr_vty_subscriber_init(hlr);
 }

src/hlr_vty.h

@@ -30,6 +30,7 @@
 enum hlr_vty_node {
 	HLR_NODE = _LAST_OSMOVTY_NODE + 1,
 	GSUP_NODE,
+	EUSE_NODE,
 };
 
 int hlr_vty_is_config_node(struct vty *vty, int node);

src/hlr_vty_subscr.c

@@ -33,8 +33,6 @@ struct vty;
 
 #define hexdump_buf(buf) osmo_hexdump_nospc((void*)buf, sizeof(buf))
 
-static struct hlr *g_hlr = NULL;
-
 static void subscr_dump_full_vty(struct vty *vty, struct hlr_subscriber *subscr)
 {
 	int rc;
@@ -478,8 +476,6 @@ DEFUN(subscriber_aud3g,
 
 void hlr_vty_subscriber_init(struct hlr *hlr)
 {
-	g_hlr = hlr;
-
 	install_element_ve(&subscriber_show_cmd);
 	install_element(ENABLE_NODE, &subscriber_create_cmd);
 	install_element(ENABLE_NODE, &subscriber_delete_cmd);

src/logging.c

@@ -19,6 +19,13 @@ const struct log_info_cat hlr_log_info_cat[] = {
 		.color = "\033[1;33m",
 		.enabled = 1, .loglevel = LOGL_NOTICE,
 	},
+	[DSS] = {
+		.name = "DSS",
+		.description = "Supplementary Services",
+		.color = "\033[1;34m",
+		.enabled = 1, .loglevel = LOGL_NOTICE,
+	},
+
 };
 
 const struct log_info hlr_log_info = {

src/logging.h

@@ -7,6 +7,7 @@ enum {
 	DDB,
 	DGSUP,
 	DAUC,
+	DSS,
 };
 
 extern const struct log_info hlr_log_info;

src/osmo-euse-demo.c

@@ -0,0 +1,196 @@
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <signal.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/application.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+
+#include <osmocom/gsm/gsup.h>
+#include <osmocom/gsm/gsm0480.h>
+#include <osmocom/gsm/protocol/gsm_04_80.h>
+
+#include <osmocom/gsupclient/gsup_client.h>
+
+#include "logging.h"
+
+static struct osmo_gsup_client *g_gc;
+
+/*! send a SS/USSD response to a given imsi/session.
+ *  \param[in] gsupc GSUP client connection through which to send
+ *  \param[in] imsi IMSI of the subscriber
+ *  \param[in] session_id Unique identifier of SS session for which this response is
+ *  \param[in] gsup_msg_type GSUP message type (OSMO_GSUP_MSGT_PROC_SS_{REQUEST,RESULT,ERROR})
+ *  \param[in] final Is this the final result (true=END) or an intermediate result (false=CONTINUE)
+ *  \param[in] msg Optional binary/BER encoded SS date (for FACILITY IE). Can be NULL. Freed in
+ *  		   this function call.
+ */
+static int euse_tx_ss(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id,
+		      enum osmo_gsup_message_type gsup_msg_type, bool final, struct msgb *ss_msg)
+{
+	struct osmo_gsup_message resp = {0};
+	struct msgb *resp_msg;
+
+	switch (gsup_msg_type) {
+	case OSMO_GSUP_MSGT_PROC_SS_REQUEST:
+	case OSMO_GSUP_MSGT_PROC_SS_RESULT:
+	case OSMO_GSUP_MSGT_PROC_SS_ERROR:
+		break;
+	default:
+		msgb_free(ss_msg);
+		return -EINVAL;
+	}
+
+	resp.message_type = gsup_msg_type;
+	OSMO_STRLCPY_ARRAY(resp.imsi, imsi);
+	if (final)
+		resp.session_state = OSMO_GSUP_SESSION_STATE_END;
+	else
+		resp.session_state = OSMO_GSUP_SESSION_STATE_CONTINUE;
+	resp.session_id = session_id;
+	if (ss_msg) {
+		resp.ss_info = msgb_data(ss_msg);
+		resp.ss_info_len = msgb_length(ss_msg);
+	}
+
+	resp_msg = gsm0480_msgb_alloc_name(__func__);
+	OSMO_ASSERT(resp_msg);
+	osmo_gsup_encode(resp_msg, &resp);
+	msgb_free(ss_msg);
+	return osmo_gsup_client_send(gsupc, resp_msg);
+}
+
+/*! send a SS/USSD reject to a given IMSI/session.
+ * \param[in] gsupc		GSUP client connection through which to send
+ * \param[in] imsi		IMSI of the subscriber
+ * \param[in] session_id	Unique identifier of SS session for which this response is
+ * \param[in] invoke_id		InvokeID of the request
+ * \param[in] problem_tag	Problem code tag (table 3.13)
+ * \param[in] problem_code	Problem code (table 3.14-3.17)
+ */
+static int euse_tx_ussd_reject(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id,
+				int invoke_id, uint8_t problem_tag, uint8_t problem_code)
+{
+	struct msgb *msg = gsm0480_gen_reject(invoke_id, problem_tag, problem_code);
+	LOGP(DMAIN, LOGL_NOTICE, "Tx %s/0x%08x: Reject(%d, 0x%02x, 0x%02x)\n", imsi, session_id,
+		invoke_id, problem_tag, problem_code);
+	OSMO_ASSERT(msg);
+	return euse_tx_ss(gsupc, imsi, session_id, OSMO_GSUP_MSGT_PROC_SS_RESULT, true, msg);
+}
+
+/*! send a SS/USSD response in 7-bit GSM default alphabet o a given imsi/session.
+ * \param[in] gsupc		GSUP client connection through which to send
+ * \param[in] imsi		IMSI of the subscriber
+ * \param[in] session_id	Unique identifier of SS session for which this response is
+ * \param[in] final		Is this the final result (true=END) or an intermediate result
+ * 				(false=CONTINUE)
+ * \param[in] invoke_id		InvokeID of the request
+ */
+static int euse_tx_ussd_resp_7bit(struct osmo_gsup_client *gsupc, const char *imsi, uint32_t session_id,
+				  bool final, uint8_t invoke_id, const char *text)
+{
+	struct msgb *ss_msg;
+
+	/* encode response; remove L3 header */
+	ss_msg = gsm0480_gen_ussd_resp_7bit(invoke_id, text);
+	LOGP(DMAIN, LOGL_DEBUG, "Tx %s/0x%08x: USSD Result(%d, %s, '%s')\n", imsi, session_id,
+		invoke_id, final ? "END" : "CONTINUE", text);
+	OSMO_ASSERT(ss_msg);
+	return euse_tx_ss(gsupc, imsi, session_id, OSMO_GSUP_MSGT_PROC_SS_RESULT, final, ss_msg);
+}
+
+static int euse_rx_proc_ss_req(struct osmo_gsup_client *gsupc, const struct osmo_gsup_message *gsup)
+{
+	char buf[GSM0480_USSD_7BIT_STRING_LEN+1];
+	struct ss_request req = {0};
+
+	if (gsup->ss_info && gsup->ss_info_len) {
+		if (gsm0480_parse_facility_ie(gsup->ss_info, gsup->ss_info_len, &req)) {
+			return euse_tx_ussd_reject(gsupc, gsup->imsi, gsup->session_id, -1,
+						   GSM_0480_PROBLEM_CODE_TAG_GENERAL,
+						   GSM_0480_GEN_PROB_CODE_BAD_STRUCTURE);
+		}
+	}
+
+	LOGP(DMAIN, LOGL_INFO, "Rx %s/0x%08x: USSD SessionState=%s, OpCode=%s, '%s'\n", gsup->imsi,
+		gsup->session_id, osmo_gsup_session_state_name(gsup->session_state),
+		gsm0480_op_code_name(req.opcode), req.ussd_text);
+
+	/* we only handle single-request-response USSD in this demo */
+	if (gsup->session_state != OSMO_GSUP_SESSION_STATE_BEGIN) {
+		return euse_tx_ussd_reject(gsupc, gsup->imsi, gsup->session_id, req.invoke_id,
+					   GSM_0480_PROBLEM_CODE_TAG_GENERAL,
+					   GSM_0480_GEN_PROB_CODE_UNRECOGNISED);
+	}
+
+	snprintf(buf, sizeof(buf), "You sent \"%s\"", req.ussd_text);
+	return euse_tx_ussd_resp_7bit(gsupc, gsup->imsi, gsup->session_id, true, req.invoke_id, buf);
+}
+
+static int gsupc_read_cb(struct osmo_gsup_client *gsupc, struct msgb *msg)
+{
+	struct osmo_gsup_message gsup_msg = {0};
+	int rc;
+
+	rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup_msg);
+	if (rc < 0) {
+		LOGP(DMAIN, LOGL_ERROR, "Error decoding GSUP: %s\n", msgb_hexdump(msg));
+		return rc;
+	}
+	DEBUGP(DMAIN, "Rx GSUP %s: %s\n", osmo_gsup_message_type_name(gsup_msg.message_type),
+		msgb_hexdump(msg));
+
+	//if (strlen(gsup_msg.imsi) < 5)
+		//return gsup_send_err_reply(gsupc, gsup.imsi, gsup.message_type, GMM_CAUSE_INV_MAND_INFO);
+
+	switch (gsup_msg.message_type) {
+	case OSMO_GSUP_MSGT_PROC_SS_REQUEST:
+	case OSMO_GSUP_MSGT_PROC_SS_RESULT:
+		euse_rx_proc_ss_req(gsupc, &gsup_msg);
+		break;
+	case OSMO_GSUP_MSGT_PROC_SS_ERROR:
+		break;
+	default:
+		LOGP(DMAIN, LOGL_DEBUG, "Unhandled GSUP message type %s\n",
+			osmo_gsup_message_type_name(gsup_msg.message_type));
+		break;
+	}
+
+	msgb_free(msg);
+	return 0;
+}
+
+
+static struct log_info_cat default_categories[] = {
+	[DMAIN] = {
+		.name = "DMAIN",
+		.description = "Main Program",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
+};
+
+static const struct log_info gsup_log_info = {
+	.cat = default_categories,
+	.num_cat = ARRAY_SIZE(default_categories),
+};
+
+int main(int argc, char **argv)
+{
+	char *server_host = "127.0.0.1";
+	uint16_t server_port = OSMO_GSUP_PORT;
+	void *ctx = talloc_named_const(NULL, 0, "demo-euse");
+
+	osmo_init_logging2(ctx, &gsup_log_info);
+
+	g_gc = osmo_gsup_client_create(ctx, "EUSE-foobar", server_host, server_port, gsupc_read_cb, NULL);
+
+	while (1) {
+		osmo_select_main(0);
+	}
+
+	exit(0);
+}
+