Unity C#环境下Ping IPv6地址的实现方案咨询

问题原因 #

你遇到的同一份代码在.NET控制台可运行、Unity 2019.4 IL2CPP环境下不可运行的问题，是该版本Unity的IL2CPP运行时对System.Net.NetworkInformation.Ping类的IPv6支持存在适配缺陷导致的，该版本IL2CPP未完整实现对应API的IPv6 ICMP调用逻辑，所以无法正常返回结果。
另外注意：Unity引擎自带的UnityEngine.Ping类仅支持IPv4地址，无法用于IPv6场景。

可行实现方案 #

方案1：手动构造ICMPv6包实现Ping（跨平台兼容性最优） #

直接通过Socket构造ICMPv6报文发送，可兼容IL2CPP环境，代码示例如下：

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using UnityEngine;

public class Ipv6Ping
{
    private const int IcmpV6EchoRequestType = 128;
    private const int IcmpV6EchoReplyType = 129;
    private const int IcmpHeaderLength = 8;

    public static PingResult Send(string ipv6Address, int timeoutMs = 5000)
    {
        if (!IPAddress.TryParse(ipv6Address, out IPAddress ip) || ip.AddressFamily != AddressFamily.InterNetworkV6)
        {
            return new PingResult { Status = IPStatus.InvalidAddress };
        }

        IPEndPoint remoteEndPoint = new IPEndPoint(ip, 0);
        using Socket socket = new Socket(AddressFamily.InterNetworkV6, SocketType.Raw, ProtocolType.IcmpV6);
        socket.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IpTimeToLive, 64);
        socket.ReceiveTimeout = timeoutMs;
        socket.SendTimeout = timeoutMs;

        // 构造ICMPv6报文
        byte[] buffer = new byte[IcmpHeaderLength + 32]; // 8字节头+32字节数据
        buffer[0] = IcmpV6EchoRequestType; // 类型：回显请求
        buffer[1] = 0; // 代码
        buffer[2] = 0; buffer[3] = 0; // 校验和先填0，后续计算
        buffer[4] = 0x12; buffer[5] = 0x34; // 标识符
        buffer[6] = 0x56; buffer[7] = 0x78; // 序列号
        Encoding.ASCII.GetBytes("test-ipv6-ping-data").CopyTo(buffer, IcmpHeaderLength);

        // 计算校验和
        ushort checkSum = CalculateChecksum(buffer, buffer.Length);
        buffer[2] = (byte)(checkSum >> 8);
        buffer[3] = (byte)(checkSum & 0xFF);

        try
        {
            DateTime sendTime = DateTime.Now;
            socket.SendTo(buffer, remoteEndPoint);

            byte[] receiveBuffer = new byte[1024];
            EndPoint receiveEndPoint = new IPEndPoint(IPAddress.IPv6Any, 0);
            int receiveLength = socket.ReceiveFrom(receiveBuffer, ref receiveEndPoint);

            if (receiveLength >= IcmpHeaderLength && receiveBuffer[0] == IcmpV6EchoReplyType)
            {
                return new PingResult
                {
                    Address = ip,
                    Status = IPStatus.Success,
                    RoundtripTime = (int)(DateTime.Now - sendTime).TotalMilliseconds
                };
            }
            return new PingResult { Status = IPStatus.Unknown };
        }
        catch (SocketException e)
        {
            return new PingResult { Status = MapSocketErrorToIpStatus(e.SocketErrorCode) };
        }
    }

    private static ushort CalculateChecksum(byte[] buffer, int length)
    {
        int sum = 0;
        for (int i = 0; i < length; i += 2)
        {
            sum += BitConverter.ToUInt16(buffer, i);
        }
        if (length % 2 != 0)
        {
            sum += buffer[length - 1] << 8;
        }
        while ((sum >> 16) != 0)
        {
            sum = (sum & 0xFFFF) + (sum >> 16);
        }
        return (ushort)~sum;
    }

    private static IPStatus MapSocketErrorToIpStatus(SocketError error)
    {
        return error switch
        {
            SocketError.TimedOut => IPStatus.TimedOut,
            SocketError.NetworkUnreachable => IPStatus.NetworkUnreachable,
            SocketError.HostUnreachable => IPStatus.DestinationHostUnreachable,
            _ => IPStatus.Unknown
        };
    }

    public class PingResult
    {
        public IPAddress Address { get; set; }
        public IPStatus Status { get; set; }
        public int RoundtripTime { get; set; }
    }
}

// 调用示例
public class Test : MonoBehaviour
{
    public void Awake()
    {
        var result = Ipv6Ping.Send("::1", 5000);
        Debug.Log($"reply {result.Address} {result.Status} 耗时:{result.RoundtripTime}ms");
    }
}

注意：该方案在Windows环境下运行需要管理员权限，移动端需要申请网络权限。

方案2：调用系统原生Ping命令（实现简单，适合非高频调用场景） #

如果不需要高频率调用Ping，可以直接调用对应平台的系统命令读取结果，实现成本极低：

using System.Diagnostics;
using System.Text;
using UnityEngine;

public static class SystemPing
{
    public static string SendIpv6(string address, int timeoutMs = 5000)
    {
        Process process = new Process();
#if UNITY_STANDALONE_WIN
        process.StartInfo.FileName = "ping.exe";
        process.StartInfo.Arguments = $"-6 {address} -w {timeoutMs} -n 1";
#elif UNITY_STANDALONE_OSX || UNITY_EDITOR_OSX || UNITY_IOS
        process.StartInfo.FileName = "ping6";
        process.StartInfo.Arguments = $"-c 1 -W {timeoutMs / 1000} {address}";
#elif UNITY_ANDROID || UNITY_STANDALONE_LINUX
        process.StartInfo.FileName = "ping6";
        process.StartInfo.Arguments = $"-c 1 -W {timeoutMs / 1000} {address}";
#endif
        process.StartInfo.UseShellExecute = false;
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.RedirectStandardError = true;
        process.StartInfo.CreateNoWindow = true;
        process.StartInfo.StandardOutputEncoding = Encoding.GetEncoding("gb2312");
        process.Start();

        string output = process.StandardOutput.ReadToEnd();
        process.WaitForExit(timeoutMs);
        return output;
    }
}

其他说明 #

如果可以升级Unity版本，建议升级到2021.3 LTS及以上版本，该版本之后IL2CPP修复了System.Net.NetworkInformation.Ping的IPv6兼容问题，你原来的代码可以直接运行。

内容的提问来源于stack exchange，提问作者Pue-Tsuâ