This crate allows the creation and usage of TUN interfaces, the aim is to make this cross-platform.

Since the original maintainer @meh is no longer interested in continuing to maintain tun at repo, We (@ssrlive, @xmh0511) created the tun2 branch repo and continued to actively update. Welcome to any interested contributor. If you want to be a co-contributor and publisher of tun2, please contact me in issues.

For me, a submitted PR has not been reviewed for a long time, cannot be merged to the main branch, and cannot be published. It is like a patient who has not been sutured on the operating table for a long time. This is a bad experience. I believe that many people feel the same.

First, add the following to your Cargo.toml:

[dependencies]
tun2 = "1"

If you want to use the TUN interface with mio/tokio, you need to enable the async feature:

[dependencies]
tun2 = { version = "1", features = ["async"] }

The following example creates and configures a TUN interface and starts reading packets from it.

use std::io::Read;

fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync + 'static>> {
    let mut config = tun2::Configuration::default();
    config
        .address((10, 0, 0, 9))
        .netmask((255, 255, 255, 0))
        .destination((10, 0, 0, 1))
        .up();

    #[cfg(target_os = "linux")]
    config.platform_config(|config| {
        // requiring root privilege to acquire complete functions
        config.ensure_root_privileges(true);
    });

    let mut dev = tun2::create(&config)?;
    let mut buf = [0; 4096];

    loop {
        let amount = dev.read(&mut buf)?;
        println!("{:?}", &buf[0..amount]);
    }
}

• Windows
• Linux
• macOS
• FreeBSD
• Android
• iOS

You will need the tun2 module to be loaded and root is required to create interfaces.

tun2 will automatically set up a route according to the provided configuration, which does a similar thing like this:

sudo route -n add -net 10.0.0.0/24 10.0.0.1

You can pass the file descriptor of the TUN device to tun2 to create the interface.

Here is an example to create the TUN device on iOS and pass the fd to tun2:

// Swift
class PacketTunnelProvider: NEPacketTunnelProvider {
    override func startTunnel(options: [String : NSObject]?, completionHandler: @escaping (Error?) -> Void) {
        let tunnelNetworkSettings = createTunnelSettings() // Configure TUN address, DNS, mtu, routing...
        setTunnelNetworkSettings(tunnelNetworkSettings) { [weak self] error in
            // The tunnel of this tunFd is contains `Packet Information` prifix.
            let tunFd = self?.packetFlow.value(forKeyPath: "socket.fileDescriptor") as! Int32
            DispatchQueue.global(qos: .default).async {
                start_tun(tunFd)
            }
            completionHandler(nil)
        }
    }
}

#[no_mangle]
pub extern "C" fn start_tun(fd: std::os::raw::c_int) {
    let mut rt = tokio::runtime::Runtime::new().unwrap();
    rt.block_on(async {
        let mut cfg = tun2::Configuration::default();
        cfg.raw_fd(fd);
        #[cfg(target_os = "ios")]
        cfg.platform_config(|p_cfg| {
            p_cfg.packet_information(true);
        });
        let mut tun = tun2::create_as_async(&cfg).unwrap();
        let mut framed = tun.into_framed();
        while let Some(packet) = framed.next().await {
            ...
        }
    });
}

You need to copy the wintun.dll file which matches your architecture to the same directory as your executable and run your program as administrator.