Udpsocket client can't get data from multicast

help
1

Hey, I am trying to write a client which gets data from multicast_v4.

and join the multicast_v4 successful.. and I can capture data by tcpdump,

but I can't get data in my socket buf. it confused me.

this is the UDP-socket-created demo, notice it's just a demo code and it's a solarflare card .
and sadly, I can't provide a testing server for some reason.

fn main() {
    let tick_udp_port = 0;
    let addrs = [SocketAddr::from(([0, 0, 0, 0], tick_udp_port))];
    let socket = UdpSocket::bind(&addrs[..]).unwrap();
    socket.set_nonblocking(true).unwrap();
    let remote_addr = "233.32.2.22:32200";
    let addr: SocketAddr = remote_addr
        .to_socket_addrs()
        .unwrap()
        .next()
        .unwrap();

    match addr.ip() {
        IpAddr::V4(ip) => socket
            .join_multicast_v4(&ip, &Ipv4Addr::UNSPECIFIED)
            .unwrap(),
        IpAddr::V6(_) => unreachable!("IPV6 found. not supported by RemAPI"),
    };
    let buf = BufferedUdp::new(socket);
    let mut udp = Udp { tick_buffered: buf };
    loop {
        if let Ok(Some(x)) = udp.next_tick_response() {
            match x {
                ResponseMessage::TickLevel2(_x) => {
                    println!("vec l2")
                }
                _ => unreachable!()
            }
        };
    }
}

I want to ask if there are some factors that cause this problem.

2

A standard strategy here is to use strace (if available) and compare the traces of a working implementation to that of Rust.

3

I will try this night.

4

You should specify the interface address that receives multicast traffic as the second argument of join_multicast_v4. If you don't specify it, it will listen the default multicast interface, which may not be what you want.

5

I have fix it by change localaddr and local_port.

6

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