如何在Rust中调用"ioctl“？并连接Linux "tun“驱动程序

extern crate libc;

use std::fs::OpenOptions;
use std::os::unix::io::AsRawFd;
use std::os::unix::io::RawFd;
use std::io::{Read, Write};

const TUNSETIFF: libc::c_ulong = 0x400454ca;
const IFF_TUN: libc::c_short = 0x0001;
const IFF_NO_PI: libc::c_short = 0x1000;

fn main() {
    let tun_fd = open_tun_device().expect("Failed to open TUN device");
    println!("TUN device opened with file descriptor: {}", tun_fd);

    // 在这里可以进行其他操作，如配置IP地址、启动网络等

    close_tun_device(tun_fd).expect("Failed to close TUN device");
}

fn open_tun_device() -> Result<RawFd, String> {
    let tun_fd = unsafe { libc::open("/dev/net/tun\0".as_ptr() as *const libc::c_char, libc::O_RDWR | libc::O_NONBLOCK) };
    if tun_fd < 0 {
        return Err(format!("Failed to open TUN device: {}", tun_fd));
    }

    let mut ifreq: libc::ifreq = unsafe { std::mem::zeroed() };
    ifreq.ifr_flags = IFF_TUN | IFF_NO_PI;

    let ioctl_result = unsafe { libc::ioctl(tun_fd, TUNSETIFF, &mut ifreq) };
    if ioctl_result < 0 {
        return Err(format!("Failed to set TUN device flags: {}", ioctl_result));
    }

    Ok(tun_fd)
}

fn close_tun_device(tun_fd: RawFd) -> Result<(), String> {
    let close_result = unsafe { libc::close(tun_fd) };
    if close_result < 0 {
        return Err(format!("Failed to close TUN device: {}", close_result));
    }

    Ok(())
}