use socket2::{Domain, Protocol, Socket, Type};
use std::io::{Error, ErrorKind};
use std::mem::MaybeUninit;
use std::net::Ipv4Addr;
use vrrpd::vrrpv2;

fn main() -> std::io::Result<()> {
    let sock = Socket::new(Domain::IPV4, Type::RAW, Some(Protocol::from(112)))?;
    sock.join_multicast_v4(
        &Ipv4Addr::new(224, 0, 0, 18),
        &Ipv4Addr::UNSPECIFIED,
    )?;
    let mut buf = [MaybeUninit::<u8>::uninit(); 512];
    let (nbytes, _) = sock.recv_from(&mut buf)?;
    let bytes = unsafe {
        std::slice::from_raw_parts(buf.as_ptr() as *const u8, nbytes)
    };
    let ihl = bytes[0] & 0xF;
    let data_offset = (ihl * 4) as usize;
    let vrrp = vrrpv2::from_bytes(&bytes[data_offset..]).map_err(|err| {
        Error::new(
            ErrorKind::InvalidData,
            format!("vrrpv2::from_bytes(): {err}"),
        )
    })?;
    eprintln!("vrrp: {vrrp:?}");
    Ok(())
}