unify allocation of gsm_subscriber_connection

The current msc_subscr_con_allocate() was in fact only used by msc_vlr_tests,
while both a_iface_bssap.c and iucs.c did their own duplicate code of
allocating the gsm_subscriber_connection struct. Unify.

Drop the old msc_subscr_con_allocate(), instead add msc_subscr_conn_alloc().
The new function also takes via_ran and lac arguments directly.

The conn allocation will soon be closely tied to the subscr_conn_fsm instance
allocation, so place the new function definition alongside the other
subscr_conn_fsm API, and match its naming ("conn").

Related: OS#3122
Change-Id: Ia57b42a149a43f9c370b1310e2e1f512183993ea

include/osmocom/msc/gsm_data.h

@@ -374,7 +374,6 @@ struct gsm_sms {
 	char text[SMS_TEXT_SIZE];
 };
 
-struct gsm_subscriber_connection *msc_subscr_con_allocate(struct gsm_network *network);
 void msc_subscr_con_free(struct gsm_subscriber_connection *conn);
 
 /* control interface handling */

include/osmocom/msc/osmo_msc.h

@@ -41,6 +41,9 @@ enum msc_compl_l3_rc {
 	MSC_CONN_REJECT = 1,
 };
 
+struct gsm_subscriber_connection *msc_subscr_conn_alloc(struct gsm_network *network,
+							enum ran_type via_ran, uint16_t lac);
+
 void msc_subscr_conn_update_id(struct gsm_subscriber_connection *conn,
 			       enum complete_layer3_type from, const char *id);
 char *msc_subscr_conn_get_conn_id(struct gsm_subscriber_connection *conn);

src/libmsc/a_iface_bssap.c

@@ -54,14 +54,10 @@ static struct gsm_subscriber_connection *subscr_conn_allocate_a(const struct a_c
 
 	LOGP(DMSC, LOGL_DEBUG, "Allocating A-Interface subscriber conn: lac %i, conn_id %i\n", lac, conn_id);
 
-	conn = talloc_zero(network, struct gsm_subscriber_connection);
+	conn = msc_subscr_conn_alloc(network, RAN_GERAN_A, lac);
 	if (!conn)
 		return NULL;
 
-	conn->network = network;
-	conn->via_ran = RAN_GERAN_A;
-	conn->lac = lac;
-
 	conn->a.conn_id = conn_id;
 	conn->a.scu = scu;
 
@@ -69,7 +65,6 @@ static struct gsm_subscriber_connection *subscr_conn_allocate_a(const struct a_c
 	 * identify later which BSC is responsible for this subscriber connection */
 	memcpy(&conn->a.bsc_addr, &a_conn_info->bsc->bsc_addr, sizeof(conn->a.bsc_addr));
 
-	llist_add_tail(&conn->entry, &network->subscr_conns);
 	LOGPCONN(conn, LOGL_DEBUG, "A-Interface subscriber connection successfully allocated!\n");
 	return conn;
 }

src/libmsc/iucs.c

@@ -57,17 +57,12 @@ static struct gsm_subscriber_connection *subscr_conn_allocate_iu(struct gsm_netw
 	DEBUGP(DIUCS, "Allocating IuCS subscriber conn: lac %d, conn_id %" PRIx32 "\n",
 	       lac, ue->conn_id);
 
-	conn = talloc_zero(network, struct gsm_subscriber_connection);
+	conn = msc_subscr_conn_alloc(network, RAN_UTRAN_IU, lac);
 	if (!conn)
 		return NULL;
 
-	conn->network = network;
-	conn->via_ran = RAN_UTRAN_IU;
 	conn->iu.ue_ctx = ue;
 	conn->iu.ue_ctx->rab_assign_addr_enc = network->iu.rab_assign_addr_enc;
-	conn->lac = lac;
-
-	llist_add_tail(&conn->entry, &network->subscr_conns);
 	return conn;
 }
 

src/libmsc/subscr_conn.c

@@ -369,6 +369,26 @@ void msc_subscr_conn_init(void)
 	osmo_fsm_register(&subscr_conn_fsm);
 }
 
+/* Allocate a new subscriber conn. */
+struct gsm_subscriber_connection *msc_subscr_conn_alloc(struct gsm_network *network,
+							enum ran_type via_ran, uint16_t lac)
+{
+	struct gsm_subscriber_connection *conn;
+
+	conn = talloc_zero(network, struct gsm_subscriber_connection);
+	if (!conn)
+		return NULL;
+
+	*conn = (struct gsm_subscriber_connection){
+		.network = network,
+		.via_ran = via_ran,
+		.lac = lac,
+	};
+
+	llist_add_tail(&conn->entry, &network->subscr_conns);
+	return conn;
+}
+
 const struct value_string complete_layer3_type_names[] = {
 	{ COMPLETE_LAYER3_NONE, "NONE" },
 	{ COMPLETE_LAYER3_LU, "LU" },

tests/msc_vlr/msc_vlr_test_rest.c

@@ -31,7 +31,7 @@ static void test_early_stage()
 	EXPECT_ACCEPTED(false);
 
 	btw("freshly allocated conn");
-	g_conn = msc_subscr_con_allocate(net);
+	g_conn = msc_subscr_conn_alloc(net, RAN_GERAN_A, 123);
 	EXPECT_ACCEPTED(false);
 
 	btw("conn_fsm present, in state NEW");

tests/msc_vlr/msc_vlr_tests.c

@@ -191,9 +191,7 @@ enum ran_type rx_from_ran = RAN_GERAN_A;
 struct gsm_subscriber_connection *conn_new(void)
 {
 	struct gsm_subscriber_connection *conn;
-	conn = msc_subscr_con_allocate(net);
-	conn->via_ran = rx_from_ran;
-	conn->lac = 23;
+	conn = msc_subscr_conn_alloc(net, rx_from_ran, 23);
 	if (conn->via_ran == RAN_UTRAN_IU) {
 		struct ranap_ue_conn_ctx *ue_ctx = talloc_zero(conn, struct ranap_ue_conn_ctx);
 		*ue_ctx = (struct ranap_ue_conn_ctx){