Function test_write

net_util/src/tap.rs:840–898

()

    #[test]
    fn test_write() {
        let tap_ip_guard = TAP_IP_LOCK.lock().unwrap();

        let mut tap = Tap::new(1).unwrap();
        let ip_addr = IpAddr::V4((*tap_ip_guard).parse().unwrap());
        let netmask = IpAddr::V4(SUBNET_MASK.parse().unwrap());
        tap.set_ip_addr(ip_addr, Some(netmask)).unwrap();
        tap.enable().unwrap();

        let (mac, _, mut rx) = pnet_get_mac_tx_rx(tap.if_name_as_str());

        let payload = DATA_STRING.as_bytes();

        // vnet hdr + eth hdr + ip hdr + udp hdr + payload len
        let buf_size = 10 + 14 + 20 + 8 + payload.len();

        let mut buf = vec![0u8; buf_size];
        // leave the vnet hdr as is
        pnet_build_packet(&mut buf[10..], mac, payload);

        tap.write_all(&buf).unwrap();
        tap.flush().unwrap();

        let (channel_tx, channel_rx) = mpsc::channel();

        // We use a separate thread to wait for the test packet because the API exposed by pnet is
        // blocking. This thread will be killed when the main thread exits.
        let _handle = thread::spawn(move || {
            loop {
                let buf = rx.next().unwrap();
                let p = ParsedPkt::new(buf);
                p.print();

                if let Some(ref udp) = p.udp
                    && payload == udp.payload()
                {
                    channel_tx.send(true).unwrap();
                    break;
                }
            }
        });

        // We wait for at most SLEEP_MILLIS * SLEEP_ITERS milliseconds for the reception of the
        // test packet to be detected.
        static SLEEP_MILLIS: u64 = 500;
        static SLEEP_ITERS: u32 = 6;

        let mut found_test_packet = false;

        for _ in 0..SLEEP_ITERS {
            thread::sleep(Duration::from_millis(SLEEP_MILLIS));
            if let Ok(true) = channel_rx.try_recv() {
                found_test_packet = true;
                break;
            }
        }

        assert!(found_test_packet);