diff --git a/tun.h b/tun.h
index 95650fa..05f62c1 100644
--- a/tun.h
+++ b/tun.h
@@ -18,7 +18,10 @@
 #ifndef __TUN_H__
 #define __TUN_H__
 
+#include <fcntl.h>
 #include <linux/if.h>
+#include <sys/uio.h>
+#include <unistd.h>
 
 #include "common.h"
 #include "ring.h"
@@ -29,9 +32,19 @@
   struct packet_ring ring;
 };
 
+// tun_open and tun_alloc are defined in tun.c and only used by clatd_microbenchmark.c
 int tun_open();
 int tun_alloc(char *dev, int fd, size_t len);
-int send_tun(int fd, clat_packet out, int iov_len);
-int set_nonblocking(int fd);
+
+/* function: send_tun
+ * sends a clat_packet to a tun interface
+ * fd      - the tun filedescriptor
+ * out     - the packet to send
+ * iov_len - the number of entries in the clat_packet
+ * returns: number of bytes read on success, -1 on failure
+ */
+static inline int send_tun(int fd, clat_packet out, int iov_len) {
+  return writev(fd, out, iov_len);
+}
 
 #endif