diff --git a/openbsc/include/sccp/sccp.h b/openbsc/include/sccp/sccp.h
index 3ad568c..69ef63c 100644
--- a/openbsc/include/sccp/sccp.h
+++ b/openbsc/include/sccp/sccp.h
@@ -143,4 +143,10 @@
 u_int32_t sccp_src_ref_to_int(struct sccp_source_reference *ref);
 struct sccp_source_reference sccp_src_ref_from_int(u_int32_t);
 
+
+/*
+ * helper functions for the nat code
+ */
+int sccp_determine_msg_type(struct msgb *msg);
+
 #endif
diff --git a/openbsc/src/sccp/sccp.c b/openbsc/src/sccp/sccp.c
index 522afcf..7e55231 100644
--- a/openbsc/src/sccp/sccp.c
+++ b/openbsc/src/sccp/sccp.c
@@ -1160,6 +1160,14 @@
 	return ref;
 }
 
+int sccp_determine_msg_type(struct msgb *msg)
+{
+	if (msgb_l2len(msg) < 1)
+		return -1;
+
+	return msg->l2h[0];
+}
+
 static __attribute__((constructor)) void on_dso_load(void)
 {
 	tall_sccp_ctx = talloc_named_const(NULL, 1, "sccp");