--- libaitrpc/src/aitrpc.c	2015/06/28 21:40:45	1.18.2.1
+++ libaitrpc/src/aitrpc.c	2015/06/29 22:29:25	1.18.2.2
@@ -3,7 +3,7 @@
 *  by Michael Pounov <misho@openbsd-bg.org>
 *
 * $Author: misho $
-* $Id: aitrpc.c,v 1.18.2.1 2015/06/28 21:40:45 misho Exp $
+* $Id: aitrpc.c,v 1.18.2.2 2015/06/29 22:29:25 misho Exp $
 *
 **************************************************************************
 The ELWIX and AITNET software is distributed under the following
@@ -377,4 +377,16 @@ rpc_Write(int sock, int type, int flags, sockaddr_t * 
 	}
 
 	return ret;
+}
+
+/*
+ * rpc_pktFreeSpace() - Get free space for payload into RPC packet
+ *
+ * @c = RPC client 
+ * return: remains free bytes from packet
+ */
+size_t
+rpc_pktFreeSpace(rpc_cli_t * __restrict c)
+{
+	return (sizeof(struct tagRPCCall) + ait_resideVars(RPC_RETVARS(c)));
 }