Option to use other tun device file

src/config.rs

@@ -17,6 +17,7 @@ use siphasher::sip::SipHasher24;
 pub struct Config {
     pub device_type: Type,
     pub device_name: String,
+    pub device_path: Option<String>,
     pub ifup: Option<String>,
     pub ifdown: Option<String>,
     pub crypto: CryptoMethod,
@@ -40,7 +41,7 @@ pub struct Config {
 impl Default for Config {
     fn default() -> Self {
         Config {
-            device_type: Type::Tap, device_name: "vpncloud%d".to_string(),
+            device_type: Type::Tap, device_name: "vpncloud%d".to_string(), device_path: None,
             ifup: None, ifdown: None,
             crypto: CryptoMethod::ChaCha20, shared_key: None,
             magic: None,
@@ -65,6 +66,9 @@ impl Config {
         if let Some(val) = file.device_name {
             self.device_name = val;
         }
+        if let Some(val) = file.device_path {
+            self.device_path = Some(val);
+        }
         if let Some(val) = file.ifup {
             self.ifup = Some(val);
         }
@@ -125,6 +129,9 @@ impl Config {
         if let Some(val) = args.flag_device {
             self.device_name = val;
         }
+        if let Some(val) = args.flag_device_path {
+            self.device_path = Some(val);
+        }
         if let Some(val) = args.flag_ifup {
             self.ifup = Some(val);
         }
@@ -213,6 +220,7 @@ impl Config {
 pub struct ConfigFile {
     pub device_type: Option<Type>,
     pub device_name: Option<String>,
+    pub device_path: Option<String>,
     pub ifup: Option<String>,
     pub ifdown: Option<String>,
     pub crypto: Option<CryptoMethod>,

src/device.rs

@@ -47,6 +47,7 @@ pub struct Device {
     type_: Type,
 }
 
+
 impl Device {
     /// Creates a new tun/tap device
     ///
@@ -67,11 +68,12 @@ impl Device {
     ///
     /// # Panics
     /// This method panics if the interface name is longer than 31 bytes.
-    pub fn new(ifname: &str, type_: Type) -> io::Result<Self> {
+    pub fn new(ifname: &str, type_: Type, path: Option<&str>) -> io::Result<Self> {
+        let path = path.unwrap_or_else(|| Self::default_path(type_));
         if type_ == Type::Dummy {
-            return Self::dummy(ifname, "/dev/null", type_);
+            return Self::dummy(ifname, path, type_);
         }
-        let fd = try!(fs::OpenOptions::new().read(true).write(true).open("/dev/net/tun"));
+        let fd = try!(fs::OpenOptions::new().read(true).write(true).open(path));
         // Add trailing \0 to interface name
         let mut ifname_string = String::with_capacity(32);
         ifname_string.push_str(ifname);
@@ -95,6 +97,15 @@ impl Device {
         }
     }
 
+    /// Returns the default device path for a given type
+    #[inline]
+    pub fn default_path(type_: Type) -> &'static str {
+        match type_ {
+            Type::Tun | Type::Tap => "/dev/net/tun",
+            Type::Dummy => "/dev/null"
+        }
+    }
+
     /// Returns the interface name of this device.
     #[inline]
     pub fn ifname(&self) -> &str {

src/main.rs

@@ -68,6 +68,7 @@ static USAGE: &'static str = include_str!("usage.txt");
 pub struct Args {
     flag_config: Option<String>,
     flag_type: Option<Type>,
+    flag_device_path: Option<String>,
     flag_mode: Option<Mode>,
     flag_shared_key: Option<String>,
     flag_crypto: Option<CryptoMethod>,
@@ -204,7 +205,7 @@ impl<P: Protocol> AnyCloud<P> {
 
 
 fn run<P: Protocol> (config: Config) {
-    let device = try_fail!(Device::new(&config.device_name, config.device_type),
+    let device = try_fail!(Device::new(&config.device_name, config.device_type, config.device_path.as_ref().map(|s| s as &str)),
         "Failed to open virtual {} interface {}: {}", config.device_type, config.device_name);
     info!("Opened device {}", device.ifname());
     let mut ranges = Vec::with_capacity(config.subnets.len());

src/tests.rs

@@ -446,6 +446,7 @@ fn config_file() {
     let config_file = "
 device_type: tun
 device_name: vpncloud%d
+device_path: /dev/net/tun
 magic: 0123ABCD
 ifup: ifconfig $IFNAME 10.0.1.1/16 mtu 1400 up
 ifdown: 'true'
@@ -470,6 +471,7 @@ stats_file: /var/log/vpncloud.stats
     assert_eq!(serde_yaml::from_str::<ConfigFile>(config_file).unwrap(), ConfigFile{
         device_type: Some(Type::Tun),
         device_name: Some("vpncloud%d".to_string()),
+        device_path: Some("/dev/net/tun".to_string()),
         ifup: Some("ifconfig $IFNAME 10.0.1.1/16 mtu 1400 up".to_string()),
         ifdown: Some("true".to_string()),
         crypto: Some(CryptoMethod::AES256),
@@ -496,6 +498,7 @@ fn config_merge() {
     config.merge_file(ConfigFile{
         device_type: Some(Type::Tun),
         device_name: Some("vpncloud%d".to_string()),
+        device_path: None,
         ifup: Some("ifconfig $IFNAME 10.0.1.1/16 mtu 1400 up".to_string()),
         ifdown: Some("true".to_string()),
         crypto: Some(CryptoMethod::AES256),
@@ -517,6 +520,7 @@ fn config_merge() {
     assert_eq!(config, Config{
         device_type: Type::Tun,
         device_name: "vpncloud%d".to_string(),
+        device_path: None,
         ifup: Some("ifconfig $IFNAME 10.0.1.1/16 mtu 1400 up".to_string()),
         ifdown: Some("true".to_string()),
         magic: Some("0123ABCD".to_string()),
@@ -539,6 +543,7 @@ fn config_merge() {
     config.merge_args(Args{
         flag_type: Some(Type::Tap),
         flag_device: Some("vpncloud0".to_string()),
+        flag_device_path: Some("/dev/null".to_string()),
         flag_ifup: Some("ifconfig $IFNAME 10.0.1.2/16 mtu 1400 up".to_string()),
         flag_ifdown: Some("ifconfig $IFNAME down".to_string()),
         flag_crypto: Some(CryptoMethod::ChaCha20),
@@ -562,6 +567,7 @@ fn config_merge() {
     assert_eq!(config, Config{
         device_type: Type::Tap,
         device_name: "vpncloud0".to_string(),
+        device_path: Some("/dev/null".to_string()),
         ifup: Some("ifconfig $IFNAME 10.0.1.2/16 mtu 1400 up".to_string()),
         ifdown: Some("ifconfig $IFNAME down".to_string()),
         magic: Some("hash:mynet".to_string()),

src/usage.txt

@@ -5,6 +5,7 @@ Options:
     --config <file>                 Read configuration options from the
                                     specified file.
     -t <type>, --type <type>        Set the type of network ("tap" or "tun").
+    --device-path <path>            Set the path of the base device.
     -d <name>, --device <name>      Name of the virtual device.
     -m <mode>, --mode <mode>        The mode of the VPN ("hub", "switch",
                                     "router", or "normal").

vpncloud.md

@@ -25,6 +25,10 @@ vpncloud(1) -- Peer-to-peer VPN
     Name of the virtual device. Any `%d` will be filled with a free number.
     [default: `vpncloud%d`]
 
+  * `--device-path <path>`:
+
+    The path of the base device inode, e.g. /dev/net/run.
+
   * `-m <mode>`, `--mode <mode>`:
 
     The mode of the VPN. The VPN can like a router, a switch or a hub. A **hub**
@@ -270,6 +274,7 @@ detailed descriptions of the options.
 
 * `device_type`: Set the type of network. Same as `--type`
 * `device_name`: Name of the virtual device. Same as `--device`
+* `device_path`: Set the path of the base device. Same as `--device-path`
 * `ifup`: A command to setup the network interface. Same as `--ifup`
 * `ifdown`: A command to bring down the network interface. Same as `--ifdown`
 * `crypto`: The encryption method to use. Same as `--crypto`