diff --git a/sideband.h b/sideband.h
--- /dev/null
+++ b/sideband.h
@@ -0,0 +1,11 @@
+#ifndef SIDEBAND_H
+#define SIDEBAND_H
+
+#define SIDEBAND_PROTOCOL_ERROR -2
+#define SIDEBAND_REMOTE_ERROR -1
+
+#define DEFAULT_PACKET_MAX 1000
+
+int recv_sideband(const char *me, int in_stream, int out, int err, char *, int);
+
+#endif