Create a TAP interface on Ubuntu 22.04.1 LTS with Rust (mkdir src && mv main.rs src && sudo cargo run)

Cargo.toml

[package]
name = "pareiodon"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
nix = "0.25.0"

main.rs

use std::os::raw::c_char;

use nix::{
    fcntl::{open, OFlag},
    ioctl_write_int, libc,
    sys::stat::Mode,
};

ioctl_write_int!(tunsetiff, b'T', 202);
ioctl_write_int!(tunsetpersist, b'T', 203);

fn main() {
    let fd = open("/dev/net/tun", OFlag::O_RDWR, Mode::empty()).unwrap();

    let mut ifr_name: [c_char; libc::IF_NAMESIZE] = [0; libc::IF_NAMESIZE];
    let name = b"tap0\0";
    ifr_name[..name.len()].copy_from_slice(&name.map(|c| c as i8)[..]);

    let ifru_flags = libc::IFF_TAP as i16;
    let ifr_ifru = libc::__c_anonymous_ifr_ifru { ifru_flags };
    let ifreq = libc::ifreq { ifr_name, ifr_ifru };

    unsafe { tunsetiff(fd, &ifreq as *const _ as _) }.unwrap();
    unsafe { tunsetpersist(fd, 1) }.unwrap();
}