diff --git a/Scurry.cabal b/Scurry.cabal
--- a/Scurry.cabal
+++ b/Scurry.cabal
@@ -1,5 +1,5 @@
 Name:          Scurry
-Version:       0.0.2
+Version:       0.0.3
 Category:      Network
 Description:   A distributed VPN system written in Haskell.
 License:       BSD3
@@ -87,6 +87,7 @@
     if os(darwin) || os(freebsd)
         build-depends: unix >= 2.3.0.0
         c-sources:          src/C/help-bsd.c
+                            src/C/tun_ioctls.h
         cc-options:         -D BSD
         cpp-options:        -DCALLCONV=ccall
  
diff --git a/src/C/tun_ioctls.h b/src/C/tun_ioctls.h
new file mode 100644
--- /dev/null
+++ b/src/C/tun_ioctls.h
@@ -0,0 +1,38 @@
+/*
+ * ip tunnel device for MacOSX.
+ */
+/*
+ * Copyright (c) 2004, 2005, 2006, 2007, 2008 Mattias Nissler <mattias.nissler@gmx.de>
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are permitted
+ * provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright notice, this list of
+ *      conditions and the following disclaimer.
+ *   2. Redistributions in binary form must reproduce the above copyright notice, this list of
+ *      conditions and the following disclaimer in the documentation and/or other materials provided
+ *      with the distribution.
+ *   3. The name of the author may not be used to endorse or promote products derived from this
+ *      software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __TUN_IOCTLS_H__
+#define __TUN_IOCTLS_H__
+
+/* Tun supports prepending a four byte address family field to each packet. These ioctls allow you
+ * to switch it on/off. Pass 1 as parameter to switch it on, pass 0 for off.
+ */
+#define TUNSIFHEAD  _IOW('t', 96, int)
+#define TUNGIFHEAD  _IOR('t', 97, int)
+
+#endif /* __TUN_IOCTLS_H__ */
+