diff --git a/openbsc/src/gsm_subscriber_base.c b/openbsc/src/gsm_subscriber_base.c
index f5fb16c..caa22a3 100644
--- a/openbsc/src/gsm_subscriber_base.c
+++ b/openbsc/src/gsm_subscriber_base.c
@@ -237,3 +237,27 @@
 	subscr->net = net;
 	return subscr;
 }
+
+struct gsm_subscriber *subscr_active_by_tmsi(struct gsm_network *net, uint32_t tmsi)
+{
+	struct gsm_subscriber *subscr;
+
+	llist_for_each_entry(subscr, subscr_bsc_active_subscriber(), entry) {
+		if (subscr->tmsi == tmsi && subscr->net == net)
+			return subscr_get(subscr);
+	}
+
+	return NULL;
+}
+
+struct gsm_subscriber *subscr_active_by_imsi(struct gsm_network *net, const char *imsi)
+{
+	struct gsm_subscriber *subscr;
+
+	llist_for_each_entry(subscr, subscr_bsc_active_subscriber(), entry) {
+		if (strcmp(subscr->imsi, imsi) == 0 && subscr->net == net)
+			return subscr_get(subscr);
+	}
+
+	return NULL;
+}