Assign 192.0.2.1 to tap0 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::{mem, os::raw::c_char};

use nix::{
    ioctl_write_ptr_bad, libc,
    sys::socket::{socket, AddressFamily, SockFlag, SockType, SockaddrIn},
};

ioctl_write_ptr_bad!(siocsifaddr, libc::SIOCSIFADDR, libc::ifreq);

fn main() {
    let sock = socket(
        AddressFamily::Inet,
        SockType::Datagram,
        SockFlag::empty(),
        None,
    )
    .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_addr = unsafe { mem::transmute(SockaddrIn::new(192, 0, 2, 1, 0).as_ref().clone()) };
    let ifr_ifru = libc::__c_anonymous_ifr_ifru { ifru_addr };
    let ifreq = libc::ifreq { ifr_name, ifr_ifru };

    unsafe { siocsifaddr(sock, &ifreq) }.unwrap();
}