diff --git a/openbsc/include/openbsc/bsc_nat.h b/openbsc/include/openbsc/bsc_nat.h
index 15e2099..9d29d26 100644
--- a/openbsc/include/openbsc/bsc_nat.h
+++ b/openbsc/include/openbsc/bsc_nat.h
@@ -498,6 +498,10 @@
 int bsc_nat_extract_lac(struct bsc_connection *bsc, struct nat_sccp_connection *con,
 				struct bsc_nat_parsed *parsed, struct msgb *msg);
 
+/**
+ * CTRL interface helper
+ */
+void bsc_nat_inform_reject(struct bsc_connection *bsc, const char *imsi);
 
 /*
  * Use for testing