Move TUN ioctl commnd to include/nuttx/net/ioctl.h so that it will always be unique. It a error in netdev_register: it was not handling device names properly when TUN is the only network device.

drivers/net/tun.c

@@ -1155,7 +1155,7 @@ static int tun_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
   FAR struct tun_device_s *priv = filep->f_priv;
   int ret = OK;
 
-  if (cmd == TUNSETIFF && !priv)
+  if (cmd == TUNSETIFF && priv == NULL)
     {
       uint8_t free_tuns;
       int intf;

include/nuttx/net/ioctl.h

@@ -119,9 +119,13 @@
 #define SIOCINQ          _SIOC(0x0025)  /* Returns the amount of queued unread
                                          * data in the receive */
 
+/* TUN/TAP driver ***********************************************************/
+
+#define TUNSETIFF        _SIOC(0x0026)  /* Set TUN/TAP interface */
+
 /* Telnet driver ************************************************************/
 
-#define SIOCTELNET       _SIOC(0x0026)  /* Create a Telnet sessions.
+#define SIOCTELNET       _SIOC(0x0027)  /* Create a Telnet sessions.
                                          * See include/nuttx/net/telnet.h */
 
 /****************************************************************************

include/nuttx/net/tun.h

@@ -52,8 +52,6 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-#define TUNSETIFF        _SIOC(0x1001)
-
 /* TUNSETIFF ifr flags */
 
 #define IFF_TUN          0x01
@@ -85,12 +83,12 @@ extern "C"
  * Name: tun_initialize
  *
  * Description:
- *   Instantiate a SLIP network interface.
+ *   Instantiate a TUN network interface.
  *
  * Parameters:
  *
  * Returned Value:
- *   OK on success; Negated errno on failure.
+ *   OK on success; Negated errno value on failure.
  *
  * Assumptions:
  *

net/netdev/netdev_register.c

@@ -68,14 +68,16 @@
 #define NETDEV_WLAN_FORMAT  "wlan%d"
 #define NETDEV_WPAN_FORMAT  "wpan%d"
 
-#if defined(CONFIG_NET_SLIP)
-#  define NETDEV_DEFAULT_FORMAT NETDEV_SLIP_FORMAT
-#elif defined(CONFIG_DRIVERS_IEEE80211) /* Usually also has CONFIG_NET_ETHERNET */
+#if defined(CONFIG_DRIVERS_IEEE80211) /* Usually also has CONFIG_NET_ETHERNET */
 #  define NETDEV_DEFAULT_FORMAT NETDEV_WLAN_FORMAT
 #elif defined(CONFIG_NET_ETHERNET)
 #  define NETDEV_DEFAULT_FORMAT NETDEV_ETH_FORMAT
 #elif defined(CONFIG_NET_6LOWPAN)
 #  define NETDEV_DEFAULT_FORMAT NETDEV_WPAN_FORMAT
+#elif defined(CONFIG_NET_SLIP)
+#  define NETDEV_DEFAULT_FORMAT NETDEV_SLIP_FORMAT
+#elif defined(CONFIG_NET_TUN)
+#  define NETDEV_DEFAULT_FORMAT NETDEV_TUN_FORMAT
 #else /* if defined(CONFIG_NET_LOOPBACK) */
 #  define NETDEV_DEFAULT_FORMAT NETDEV_LO_FORMAT
 #endif