java - Ping 整个网络以查找设备

Question

我正在尝试在 5000 端口上将本地网络从 192.168.1.0 ping 到 192.168.1.255，Arduino 板也通过 5000 端口连接到网络。我有开发板的 Mac 地址并试图查找 IP 地址。这是我的代码

static void pingLocal() {
    for (int i = 0; i <= 255; i++) {
        ping("192.168.1." + i + ":5000");
    }
}

private static void ping(String url) {
    try {
        Process mIpAddrProcess = Runtime.getRuntime().exec("/system/bin/ping -c 1 " + url);
        int mExitValue = mIpAddrProcess.waitFor();
        System.out.println(" mExitValue " + mExitValue);
        if (mExitValue == 0) {
            Log.d("log", "true");
        } else {
            Log.d("log", "false");
        }
    } catch (IOException | InterruptedException e) {
        e.printStackTrace();
    }
}

static String getIPFromArpCache(String mac) {
    if (mac == null)
        return null;
    BufferedReader br = null;
    try {
        br = new BufferedReader(new FileReader("/proc/net/arp"));
        String line;
        while ((line = br.readLine()) != null) {
            Log.d("line", line);
            String[] splitted = line.split(" +");
            if (splitted.length >= 4 && mac.equals(splitted[3])) {
                String ip = splitted[0];
                if (ip.split(".").length == 4) {
                    return ip;
                } else {
                    return null;
                }
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            assert br != null;
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return null;
}

这是结果

02-20 19:57:07.465 12103-12103/ir.shafadoc.handset D/line: IP address       HW type     Flags       HW address            Mask     Device
02-20 19:57:07.466 12103-12103/ir.shafadoc.handset D/line: 192.168.1.33     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.466 12103-12103/ir.shafadoc.handset D/line: 192.168.1.26     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.467 12103-12103/ir.shafadoc.handset D/line: 192.168.1.19     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.467 12103-12103/ir.shafadoc.handset D/line: 192.168.1.12     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.467 12103-12103/ir.shafadoc.handset D/line: 192.168.1.31     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.468 12103-12103/ir.shafadoc.handset D/line: 192.168.1.24     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.468 12103-12103/ir.shafadoc.handset D/line: 192.168.1.17     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.469 12103-12103/ir.shafadoc.handset D/line: 192.168.1.10     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.470 12103-12103/ir.shafadoc.handset D/line: 192.168.1.29     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.470 12103-12103/ir.shafadoc.handset D/line: 192.168.1.22     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.470 12103-12103/ir.shafadoc.handset D/line: 192.168.1.15     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.471 12103-12103/ir.shafadoc.handset D/line: 192.168.1.8      0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.471 12103-12103/ir.shafadoc.handset D/line: 192.168.1.1      0x1         0x2         c0:a0:bb:9a:e4:ad     *        wlan0
02-20 19:57:07.472 12103-12103/ir.shafadoc.handset D/line: 192.168.1.27     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.472 12103-12103/ir.shafadoc.handset D/line: 192.168.1.20     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.472 12103-12103/ir.shafadoc.handset D/line: 192.168.1.13     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.473 12103-12103/ir.shafadoc.handset D/line: 192.168.1.32     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.473 12103-12103/ir.shafadoc.handset D/line: 192.168.1.25     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.473 12103-12103/ir.shafadoc.handset D/line: 192.168.1.18     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.474 12103-12103/ir.shafadoc.handset D/line: 192.168.1.11     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.474 12103-12103/ir.shafadoc.handset D/line: 192.168.1.30     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.475 12103-12103/ir.shafadoc.handset D/line: 192.168.1.23     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.475 12103-12103/ir.shafadoc.handset D/line: 192.168.1.16     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.475 12103-12103/ir.shafadoc.handset D/line: 192.168.1.9      0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.476 12103-12103/ir.shafadoc.handset D/line: 192.168.1.28     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.476 12103-12103/ir.shafadoc.handset D/line: 192.168.1.21     0x1         0x0         00:00:00:00:00:00     *        wlan0
02-20 19:57:07.477 12103-12103/ir.shafadoc.handset D/line: 192.168.1.14     0x1         0x0         00:00:00:00:00:00     *        wlan0

如您所见，只有调制解调器在 arp 缓存中有 Mac 地址。怎么了？如何从 Mac 发现网络和查找 IP 地址？

Answer 1

我发现了这种 ping 网络的方法，而且效果很好

if (InetAddress.getByName(host).isReachable(timeout)) {
      System.out.println(host + " is reachable");
}