subscr_conn: store complete_layer3_type in conn, not FSM event arg

Instead of jumping through hoops to pass the Complete Layer 3 operation that
created this conn via FSM event dispatch parameters, put it right in the
gsm_subscriber_connection struct, where it always belonged.

Move definition of the enum complete_layer3_type to gsm_data.h, where
gsm_subscriber_connection is defined.

Introduce msc_subscr_conn_update_id() to set the complete_layer3_type of the
conn as soon as a Complete Layer 3 message is received.

In msc_subscr_conn_update_id(), already include an mi_string argument to
prepare for an upcoming patch where the FSM will be allocated much earlier when
the Mobile Identity is not known yet, and we'll also update the fi->id here.

The odd logging change in the msc_vlr_tests output uncovers a wrong use of the
osmo_fsm_inst_dispatch() data argument for SUBSCR_CONN_E_CN_CLOSE events: if a
child FSM signals unsuccessful result, instead of the failure cause, it passed
the complete_layer3_type, as requested upon FSM allocation, which was then
misinterpreted as a failure cause. Now a child FSM failure will pass NULL
instead, while other SUBSCR_CONN_E_CN_CLOSE events may still pass a valid cause
value.

Related: OS#3122
Change-Id: Iae30dd57a8861c4eaaf56999f872d4e635ba97fb

2 files changed, 16 insertions, 13 deletions

diff --git a/include/osmocom/msc/gsm_data.h b/include/osmocom/msc/gsm_data.h
index df15eea02..29abd5d20 100644
--- a/include/osmocom/msc/gsm_data.h
+++ b/include/osmocom/msc/gsm_data.h
@@ -70,6 +70,19 @@ enum integrity_protection_state {
 	INTEGRITY_PROTECTION_IK_CK	= 2,
 };
 
+enum complete_layer3_type {
+	COMPLETE_LAYER3_NONE,
+	COMPLETE_LAYER3_LU,
+	COMPLETE_LAYER3_CM_SERVICE_REQ,
+	COMPLETE_LAYER3_PAGING_RESP,
+};
+
+extern const struct value_string complete_layer3_type_names[];
+static inline const char *complete_layer3_type_name(enum complete_layer3_type val)
+{
+	return get_value_string(complete_layer3_type_names, val);
+}
+
 /* active radio connection of a mobile subscriber */
 struct gsm_subscriber_connection {
 	/* global linked list of subscriber_connections */
@@ -77,6 +90,7 @@ struct gsm_subscriber_connection {
 
 	/* FSM instance to control the subscriber connection's permissions and lifetime. */
 	struct osmo_fsm_inst *fi;
+	enum complete_layer3_type complete_layer3_type;
 
 	/* usage count. If this drops to zero, we start the release
 	 * towards A/Iu */
diff --git a/include/osmocom/msc/osmo_msc.h b/include/osmocom/msc/osmo_msc.h
index d838e89d4..fb525e000 100644
--- a/include/osmocom/msc/osmo_msc.h
+++ b/include/osmocom/msc/osmo_msc.h
@@ -36,24 +36,13 @@ enum subscr_conn_fsm_state {
 	SUBSCR_CONN_S_RELEASED,
 };
 
-enum complete_layer3_type {
-	SUBSCR_CONN_FROM_INVALID,
-	SUBSCR_CONN_FROM_LU,
-	SUBSCR_CONN_FROM_CM_SERVICE_REQ,
-	SUBSCR_CONN_FROM_PAGING_RESP,
-};
-
-extern const struct value_string complete_layer3_type_names[];
-static inline const char *complete_layer3_type_name(enum complete_layer3_type val)
-{
-	return get_value_string(complete_layer3_type_names, val);
-}
-
 enum msc_compl_l3_rc {
 	MSC_CONN_ACCEPT = 0,
 	MSC_CONN_REJECT = 1,
 };
 
+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);
 int msc_create_conn_fsm(struct gsm_subscriber_connection *conn, const char *id);