diff --git a/src/libvlr/vlr_core.h b/src/libvlr/vlr_core.h
new file mode 100644
index 0000000..0e63c7e
--- /dev/null
+++ b/src/libvlr/vlr_core.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <openbsc/vlr.h>
+
+#define LOGGSUPP(level, gsup, fmt, args...) \
+	LOGP(DVLR, level, "GSUP(%s) " fmt, \
+	     (gsup)->imsi, \
+	     ## args)
+
+#define LOGVSUBP(level, vsub, fmt, args...) \
+	LOGP(DVLR, level, "SUBSCR(%s) " fmt, \
+		vlr_subscr_name(vsub), ## args)
+
+
+const char *vlr_subscr_name(struct vlr_subscr *vsub);
+int vlr_subscr_req_lu(struct vlr_subscr *vsub, bool is_ps);
+int vlr_subscr_req_sai(struct vlr_subscr *vsub, const uint8_t *auts,
+		       const uint8_t *auts_rand);
+struct vlr_subscr *vlr_subscr_alloc(struct vlr_instance *vlr);
+void vlr_subscr_update_tuples(struct vlr_subscr *vsub,
+			      const struct osmo_gsup_message *gsup);