Ping.SendAsync() 从 0.0.0.0 返回重播，如何获取 ping 地址？答案

【问题标题】：Ping.SendAsync() returned replay from 0.0.0.0, how to get pinged address?Ping.SendAsync() 从 0.0.0.0 返回重播，如何获取 ping 地址？
【发布时间】：2011-07-06 20:54:56
【问题描述】：

我对 C# 中的 Ping.SendAsync() 函数有疑问。我ping了一些IP地址，但其中一些是错误的。我需要从列表中删除错误的地址。但是如何，因为 p_PingCompleted event args.replay.adress 是 0.0.0.0？这是我的代码：

System.Collections.Generic.List<Game> GameList = new System.Collections.Generic.List<Game>();
System.Timers.Timer timer = new System.Timers.Timer(5000);

        public StartServer()
        {
            this.tcpListener = new TcpListener(IPAddress.Any, 8888);
            this.listenThread = new Thread(new ThreadStart(ListenForClients));
            this.listenThread.Start();
            Console.WriteLine("Master server running...");
            timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
            timer.Start();
        }

        void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            Game[] games = GameList.ToArray();
            foreach (Game curgame in games)
            {
                System.Net.NetworkInformation.Ping p = new System.Net.NetworkInformation.Ping();
                p.PingCompleted += new System.Net.NetworkInformation.PingCompletedEventHandler(p_PingCompleted);
                p.SendAsync(IPAddress.Parse(curgame.IP), new object());
            }
            SendMessageToAll(output);
            Console.WriteLine("Timer.Elapsed with data [" + output + "]");
        }

        void p_PingCompleted(object sender, System.Net.NetworkInformation.PingCompletedEventArgs e)
        {
            Console.WriteLine("Ping reply from: " + e.Reply.Address.ToString() + " has " + e.Reply.RoundtripTime.ToString() + " ms.");
            if (e.Reply.RoundtripTime == 0 ||
                e.Reply.RoundtripTime >= 2500)
            {
                Console.WriteLine("   Removing this server because ping is 0 or is greater than 2500 ms");
            }
        }

输出是：

Pinging 16.5.4.3...
Ping reply from: 0.0.0.0 has 0 ms.

【问题讨论】：

标签： c# .net networking asynchronous ping

【解决方案1】：

您可以使用UserState property 和锁来确保对GameList 的序列化访问：

byte[] buffer = Encoding.ASCII.GetBytes (new string('a', 32));
var options = new PingOptions (32, true);

Ping p = new Ping();
p.PingCompleted += p_PingCompleted;
foreach (Game curgame in GameList.ToArray())
{
    // e.UserState will be curgame
    p.SendAsync(IPAddress.Parse(curgame.IP), 2500, buffer, options, curgame);
}

然后在您的p_PingCompleted 处理程序中：

void p_PingCompleted(object sender, PingCompletedEventArgs e)
{
    var game = (Game)e.UserState;
    if (e.Reply.Status != IPStatus.Success)
    {
        Console.WriteLine(
            "  Could not reach {0} ({1}), removing this server...",
            game.IP,
            e.Reply.Status);
        lock (GameList)
        {
            GameList.Remove(game);
        }
    }
    else
    {
        Console.WriteLine(
            "Ping reply from: {0} in {1} ms",
            e.Reply.Address,
            e.Reply.RoundtripTime);
        if (e.Reply.RoundtripTime == 0 ||
            e.Reply.RoundtripTime >= 2500)
        {
            Console.WriteLine("  Ping too high, removing this server...");
            lock (GameList)
            {
                GameList.Remove(game);
            }
        }
    }
}

【讨论】：

这很好，但不能解释为什么他的 IP 得到 0.0.0.0。
@0A0D：我敢打赌，在这些情况下PingReply.Status 类似于无法到达的目的地。

【解决方案2】：

在异步调用中，发送 Ping 对象（或游戏对象，无论您正在处理的任何列表）作为对象状态，然后从 ping 完成事件中，如果地址无效，只需从列表中删除该对象.

【讨论】：

你的意思是p.SendAsync(IPAddress.Parse(curgame.IP), curgame);？
是的。只需在 ping 完成的代码中使用，GamesList.Remove(e.UserState);

【解决方案3】：

我认为这与您使用 SendAsync(string, object) 的方式有关。

MSDN 有一个很好的例子。请改用SendAsync(String, Int32, Byte[], PingOptions, Object) 或SendAsync(IPAddress, Int32, Byte[], PingOptions, Object)。按照那个例子，它应该适合你。

【讨论】：