如何用C#实现类Linux的UDP Traceroute排查游戏服务器延迟？

近期我和其他《行星边际2》玩家都遇到高延迟问题，需要排查路由节点故障。Windows自带的tracert和Ping工具只能获取前几个节点，后续返回* * *，推测是服务器防火墙拦截导致。但Linux下的UDP traceroute命令（traceroute -U -p 20105 69.174.216.21）可以成功获取完整路由：

1  Desktop (my ip)  0.340 ms
2  router (router ip)  3.305 ms
3  isp (isp ip)  8.955 ms
4  62.214.42.189 (62.214.42.189)  10.675 ms
5  62.67.18.94 (62.67.18.94)  15.491 ms
6  * * *
7  * * *
8  * * *
9  * * *
10  8.227.56.190 (8.227.56.190)  99.620 ms
11  69.174.217.5 (69.174.217.5)  98.522 ms
12  69.174.216.21 (69.174.216.21)  103.844 ms

因为不是所有玩家都熟悉Linux，我想开发一个C#版本的工具供社区使用，但遇到了以下问题：

• ICMP实现问题：只能遍历前5个TTL节点，后续节点多次尝试均失败，无法到达目标IP，结果如下：

1 Desktop IP       TtlExpired
2 Router IP        TtlExpired
3 ISP IP           TtlExpired
4 62.214.42.189    TtlExpired
5 62.67.18.94      TtlExpired
6                  failed after 3 attempts.
7                  failed after 3 attempts.
8                  failed after 3 attempts.
9                  failed after 3 attempts.
10 8.227.56.190    DestinationNetworkUnreachable
11                 failed after 3 attempts.
12                 failed after 3 attempts.

• UDP实现问题：前6个节点触发SocketException/AggregateException（连接因保活检测终止），仅能识别目标IP，无法获取中间节点IP，结果如下：

Traceroute[0]:  - Keepalive blocked
Traceroute[1]:  - Keepalive blocked
Traceroute[2]:  - Keepalive blocked
Traceroute[3]:  - Keepalive blocked
Traceroute[4]:  - Keepalive blocked
Traceroute[5]:  - No response received
Traceroute[6]:  - No response received
Traceroute[7]:  - No response received
Traceroute[8]:  - No response received
Traceroute[9]:  - No response received
Traceroute[10]:  - Keepalive blocked
Traceroute[11]:  - Keepalive blocked
Traceroute[11]: 69.174.216.21 - Target reached

• TCP实现完全失败

我试过Stack Overflow上的相关示例但没用，了解到可能需要用原始套接字监听ICMP TIME_EXCEEDED，但不知道具体怎么实现。附上现有ICMP和UDP代码，请求指导如何修正代码，实现类似Linux的UDP Traceroute功能以获取完整路由节点。

ICMP代码 #

var limit = 15;
var buffer = new byte[32];
var pingOpts = new PingOptions(1, true);
var ping = new Ping();

PingReply result = null;

do
{
    int retries = 0;
    pingOpts = new PingOptions(pingOpts.Ttl + 1, pingOpts.DontFragment);

    while (retries < 3)
    {
        result = ping.Send(ipAddress, 1000, buffer, pingOpts);

        if (result.Status != IPStatus.TimedOut)
        {
            yield return result;
            break;
        }

        retries++;
    }

    if (retries == 3)
    {
        Console.WriteLine($"TTL {pingOpts.Ttl} failed after 3 attempts.");
    }
}
while (result.Status != IPStatus.Success && pingOpts.Ttl < limit);

UDP代码 #

for (short ttl = 0; ttl <= 15; ttl++)
{
    string message = $"Traceroute[{ttl}]: ";

    try
    {

        using (UdpClient udpClient = new UdpClient())
        {
            udpClient.Client.ReceiveTimeout = 3000;
            udpClient.Client.Ttl = ttl;
            udpClient.DontFragment = true;

            udpClient.Send(new byte[1], 1, ipAddress, targetPort);

            Task<UdpReceiveResult> receiveTask = udpClient.ReceiveAsync();

            if (await Task.WhenAny(receiveTask, Task.Delay(3000)) == receiveTask)
            {

                UdpReceiveResult result = receiveTask.Result; //crashes here because of keep-alive smth
                IPAddress senderIp = result.RemoteEndPoint.Address;

                if (senderIp.Equals(IPAddress.Parse(ipAddress)))
                {
                    Console.WriteLine(message + ipAddress.ToString() + " - Target reached");
                }
                else
                {
                    Console.WriteLine(message + $" - Received response from {senderIp}");
                }
            }
            else
            {
                Console.WriteLine(message + " - No response received");
            }
        }
    }
    catch (SocketException ex)
    {
        if (ex.SocketErrorCode == SocketError.TimedOut)
        {
            Console.WriteLine(message + " - No response received");
        }
    }
    catch (System.AggregateException ex)
    {
        Console.WriteLine(message + " - Keepalive blocked");
    }

}

内容的提问来源于stack exchange，提问作者Little Yuuta