Add TUN device. From Max Neklyudov

drivers/net/Make.defs

@@ -67,6 +67,10 @@ ifeq ($(CONFIG_NET_SLIP),y)
   CSRCS += slip.c
 endif
 
+ifeq ($(CONFIG_NET_TUN),y)
+  CSRCS += tun.c
+endif
+
 ifeq ($(CONFIG_ARCH_PHY_INTERRUPT),y)
   CSRCS += phy_notify.c
 endif

include/nuttx/net/net.h

@@ -73,7 +73,8 @@ enum net_lltype_e
 {
   NET_LL_ETHERNET = 0, /* Ethernet */
   NET_LL_SLIP,         /* Serial Line Internet Protocol (SLIP) */
-  NET_LL_PPP           /* Point-to-Point Protocol (PPP) */
+  NET_LL_PPP,          /* Point-to-Point Protocol (PPP) */
+  NET_LL_TUN,          /* TUN Virtual Network Device */
 };
 
 /* This defines a bitmap big enough for one bit for each socket option */

include/nuttx/net/tun.h

@@ -0,0 +1,104 @@
+/****************************************************************************
+ * include/nuttx/net/tun.h
+ *
+ *   Copyright (C) 2015 Max Nekludov. All rights reserved.
+ *   Author : Max Nekludov <macscomp@gmail.com>
+ *
+ * Includes some definitions that a compatible with the LGPL GNU C Library
+ * header file of the same name.
+ *
+ * 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. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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
+ * COPYRIGHT OWNER OR CONTRIBUTORS 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 __INCLUDE_NUTTX_NET_TUN_H
+#define __INCLUDE_NUTTX_NET_TUN_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/net/ioctl.h>
+
+#ifdef CONFIG_NET_TUN
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define TUNSETIFF        _SIOC(0x1001)
+
+/* TUNSETIFF ifr flags */
+
+#define IFF_TUN          0x0001
+
+/****************************************************************************
+ * Public Type Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: tun_initialize
+ *
+ * Description:
+ *   Instantiate a SLIP network interface.
+ *
+ * Parameters:
+ *
+ * Returned Value:
+ *   OK on success; Negated errno on failure.
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+int tun_initialize(void);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /*  CONFIG_NET_TUN */
+#endif /* __INCLUDE_NUTTX_NET_TUN_H */

net/Kconfig

@@ -102,6 +102,17 @@ config NET_SLIP_TCP_RECVWNDO
 		incoming data, or high (32768 bytes) if the application processes
 		data quickly.
 
+config NET_TUN_MTU
+	int "TUN packet buffer size (MTU)"
+	default 296
+	depends on NET_TUN
+	range 296 1518
+
+config NET_TUN_TCP_RECVWNDO
+	int "TUN TCP receive window size"
+	default 256
+	depends on NET_TUN && NET_TCP
+
 config NET_GUARDSIZE
 	int "Driver I/O guard size"
 	default 2
@@ -121,6 +132,13 @@ config NET_MULTILINK
 	bool
 	default n
 
+config NET_USER_DEVFMT
+	bool "User provided devfmt"
+	default n
+	depends on EXPERIMENTAL
+	---help---
+		netdev_register will get devfmt form d_ifname if it is initialized.
+
 config NET_ETHERNET
 	bool "Ethernet support"
 	default y if !NET_SLIP
@@ -179,6 +197,24 @@ config SLIP_DEFPRIO
 		The priority of the SLIP RX and TX tasks. Default: 128
 
 endif # NET_SLIP
+
+config NET_TUN
+	bool "TUN Virtual Network Device support"
+	default n
+
+if NET_TUN
+
+config TUN_NINTERFACES
+	int "Number of TUN interfaces"
+	default 1
+	range 1 8
+	---help---
+		Selects the number of TUN
+		interfaces to support.
+		Default: 1
+
+endif # NET_TUN
+
 endmenu # Data link support
 
 source "net/netdev/Kconfig"

net/netdev/netdev_register.c

@@ -62,6 +62,7 @@
 
 #define NETDEV_SLIP_FORMAT      "sl%d"
 #define NETDEV_ETH_FORMAT       "eth%d"
+#define NETDEV_TUN_FORMAT       "tun%d"
 
 #if defined(CONFIG_NET_SLIP)
 #  define NETDEV_DEFAULT_FORMAT NETDEV_SLIP_FORMAT
@@ -171,6 +172,9 @@ static int find_devnum(FAR const char *devfmt)
 int netdev_register(FAR struct net_driver_s *dev, enum net_lltype_e lltype)
 {
   FAR const char *devfmt;
+#ifdef CONFIG_NET_USER_DEVFMT
+  FAR const char devfmt_str[IFNAMSIZ];
+#endif
   int devnum;
 
   if (dev)
@@ -206,6 +210,17 @@ int netdev_register(FAR struct net_driver_s *dev, enum net_lltype_e lltype)
             break;
 #endif
 
+#ifdef CONFIG_NET_TUN
+          case NET_LL_TUN:       /* Virtual Network Device (TUN) */
+            dev->d_llhdrlen = 0;
+            dev->d_mtu      = CONFIG_NET_TUN_MTU;
+#ifdef CONFIG_NET_TCP
+            dev->d_recvwndo = CONFIG_NET_TUN_TCP_RECVWNDO;
+#endif
+            devfmt          = NETDEV_TUN_FORMAT;
+            break;
+#endif
+
 #if 0                            /* REVISIT: Not yet supported */
           case NET_LL_PPP:       /* Point-to-Point Protocol (PPP) */
             dev->d_llhdrlen = 0;
@@ -242,6 +257,14 @@ int netdev_register(FAR struct net_driver_s *dev, enum net_lltype_e lltype)
 #else
       devnum = g_next_devnum++;
 #endif
+#ifdef CONFIG_NET_USER_DEVFMT
+      if (*dev->d_ifname)
+        {
+          strncpy(devfmt_str, dev->d_ifname, IFNAMSIZ);
+          devfmt = devfmt_str;
+        }
+#endif
+
       snprintf(dev->d_ifname, IFNAMSIZ, devfmt, devnum );
 
       /* Add the device to the list of known network devices */