notify GSUP clients when HLR subscriber information changes

Add a function which triggers subscriber update notifications to
all connected GSUP clients, and invoke it when the MSISDN of a
subscriber is changed via VTY.

This makes the TTCN3 HLR test TC_vty_msisdn_isd pass.

Note that the new function currently relies on implementation
details of the Location Update Operation (luop) code.
Because of this we currently log a slightly misleading message
when the updated Insert Subscriber Data message is sent:
  "luop.c:161 LU OP state change: LU RECEIVED -> ISD SENT"
This message is misleading because, in fact, no location update
message was received from a GSUP client at that moment.

So while this change fixes the externally visible behaviour, we may
want to follow this up with some refactoring to avoid relying on
luop internals. It seems acceptable to do that in a separate step
since such a change will be more involved and harder to review.

We may want to trigger such notifications in other situations as well.
This is left for future work, too. There are no TTCN3 test cases for
other situations yet, as far as I can see.

Related: OS#2785
Change-Id: Iffe1d7afb9fc7dbae542f70bbf5391ddc08a14b4

3 files changed, 40 insertions, 0 deletions

diff --git a/src/hlr.c b/src/hlr.c
index 838b1bc..4fbc268 100644
--- a/src/hlr.c
+++ b/src/hlr.c
@@ -46,6 +46,38 @@
 
 static struct hlr *g_hlr;
 
+/* Trigger 'Insert Subscriber Data' messages to all connected GSUP clients.
+ *
+ * FIXME: In order to support large-scale networks this function should skip
+ * VLRs/SGSNs which do not currently serve the subscriber.
+ *
+ * \param[in] subscr  A subscriber we have new data to send for.
+ */
+void
+osmo_hlr_subscriber_update_notify(struct hlr_subscriber *subscr)
+{
+        struct osmo_gsup_conn *co;
+
+	if (g_hlr->gs == NULL)
+		return;
+
+	llist_for_each_entry(co, &g_hlr->gs->clients, list) {
+		struct lu_operation *luop = lu_op_alloc_conn(co);
+		if (!luop) {
+			LOGP(DMAIN, LOGL_ERROR,
+			       "IMSI='%s': Cannot notify GSUP client, cannot allocate lu_operation,"
+			       " for %s:%u\n", subscr->imsi,
+			       co && co->conn && co->conn->server? co->conn->server->addr : "unset",
+			       co && co->conn && co->conn->server? co->conn->server->port : 0);
+			continue;
+		}
+		luop->subscr = *subscr;
+		luop->state = LU_S_LU_RECEIVED; /* Pretend we received a location update. */
+		lu_op_tx_insert_subscr_data(luop);
+		lu_op_free(luop);
+	}
+}
+
 /***********************************************************************
  * Send Auth Info handling
  ***********************************************************************/
diff --git a/src/hlr.h b/src/hlr.h
index f63bc2b..368a052 100644
--- a/src/hlr.h
+++ b/src/hlr.h
@@ -38,3 +38,7 @@ struct hlr {
 	/* Local bind addr */
 	char *gsup_bind_addr;
 };
+
+struct hlr_subscriber;
+
+void osmo_hlr_subscriber_update_notify(struct hlr_subscriber *subscr);
diff --git a/src/hlr_vty_subscr.c b/src/hlr_vty_subscr.c
index 7191a1c..4092a8f 100644
--- a/src/hlr_vty_subscr.c
+++ b/src/hlr_vty_subscr.c
@@ -257,6 +257,10 @@ DEFUN(subscriber_msisdn,
 
 	vty_out(vty, "%% Updated subscriber IMSI='%s' to MSISDN='%s'%s",
 		subscr.imsi, msisdn, VTY_NEWLINE);
+
+	if (db_subscr_get_by_msisdn(g_hlr->dbc, msisdn, &subscr) == 0)
+		osmo_hlr_subscriber_update_notify(&subscr);
+
 	return CMD_SUCCESS;
 }