Import upstream version 0.9.13
diff --git a/include/openbsc/silent_call.h b/include/openbsc/silent_call.h
new file mode 100644
index 0000000..2492903
--- /dev/null
+++ b/include/openbsc/silent_call.h
@@ -0,0 +1,12 @@
+#ifndef _SILENT_CALL_H
+#define _SILENT_CALL_H
+
+struct gsm_subscriber_connection;
+
+extern int gsm_silent_call_start(struct gsm_subscriber *subscr,
+                                 void *data, int type);
+extern int gsm_silent_call_stop(struct gsm_subscriber *subscr);
+extern int silent_call_rx(struct gsm_subscriber_connection *conn, struct msgb *msg);
+extern int silent_call_reroute(struct gsm_subscriber_connection *conn, struct msgb *msg);
+
+#endif /* _SILENT_CALL_H */