feat: detect an agent's public IPv4 and IPv6 addresses automatically, manual values still win [CI]

backend/shared/MoShiro.Measurement/Platform/LocalAddresses.cs

@@ -0,0 +1,106 @@
+using System.Globalization;
+using System.Net;
+using System.Net.NetworkInformation;
+using System.Net.Sockets;
+using MoShiro.Protocol;
+
+namespace MoShiro.Measurement;
+
+/// <summary>
+/// 本机的公网地址：Agent 注册之后在 hello 里上报，面板用它自动填 <c>public_host</c> 和 <c>ipv6_host</c>，不需要管理员手填。
+/// 只列出「别人能拨进来」的地址：IPv4 要排除私网、CGNAT、回环、链路本地；IPv6 只要全球单播（2000::/3），
+/// 并且排除临时地址、tentative、deprecated 和文档/6to4/Teredo 段。读不到网卡信息时返回空，面板退回到管理员手填或观察到的来源地址。
+/// </summary>
+public static class LocalAddresses
+{
+    public static IReadOnlyList<string> Sample()
+    {
+        var result = new List<string>();
+        HashSet<string> unusable = OperatingSystem.IsLinux() ? UnusableIpv6(Read("/proc/net/if_inet6")) : [];
+        try
+        {
+            foreach (NetworkInterface adapter in NetworkInterface.GetAllNetworkInterfaces())
+            {
+                if (adapter.OperationalStatus != OperationalStatus.Up || adapter.NetworkInterfaceType is NetworkInterfaceType.Loopback or NetworkInterfaceType.Tunnel)
+                {
+                    continue;
+                }
+
+                foreach (UnicastIPAddressInformation unicast in adapter.GetIPProperties().UnicastAddresses)
+                {
+                    IPAddress address = unicast.Address;
+                    bool usable = address.AddressFamily == AddressFamily.InterNetwork
+                        ? PublicAddress.IsPublicIpv4(address)
+                        : PublicAddress.IsGlobalIpv6(address) && !unusable.Contains(address.ToString()) && !IsTemporary(unicast);
+                    if (usable && !result.Contains(address.ToString()))
+                    {
+                        result.Add(address.ToString());
+                    }
+                }
+            }
+        }
+        catch (Exception ex) when (ex is NetworkInformationException or PlatformNotSupportedException)
+        {
+            return [];
+        }
+
+        // 稳定顺序：同一台机器每次上报的顺序一样，面板不会因为顺序变化而改地址
+        result.Sort(StringComparer.Ordinal);
+        return result;
+    }
+
+    /// <summary>Linux 的 <c>/proc/net/if_inet6</c>：临时（0x01）、dadfailed（0x08）、deprecated（0x20）、tentative（0x40）的地址不能当作对外地址。</summary>
+    public static HashSet<string> UnusableIpv6(string? procNetIfInet6)
+    {
+        var result = new HashSet<string>(StringComparer.Ordinal);
+        if (procNetIfInet6 is null)
+        {
+            return result;
+        }
+
+        foreach (string line in procNetIfInet6.Split('\n'))
+        {
+            string[] fields = line.Split((char[]?)null, StringSplitOptions.RemoveEmptyEntries);
+            if (fields.Length != 6 || fields[0].Length != 32 || !uint.TryParse(fields[4], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out uint flags) || (flags & 0x69) == 0)
+            {
+                continue;
+            }
+
+            var bytes = new byte[16];
+            for (int i = 0; i < 16; i++)
+            {
+                bytes[i] = byte.Parse(fields[0].AsSpan(i * 2, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture);
+            }
+
+            result.Add(new IPAddress(bytes).ToString());
+        }
+
+        return result;
+    }
+
+    // Windows 和 macOS：随机后缀就是隐私（临时）地址
+    private static bool IsTemporary(UnicastIPAddressInformation unicast)
+    {
+        try
+        {
+            return OperatingSystem.IsWindows()
+                && (unicast.SuffixOrigin == SuffixOrigin.Random || unicast.DuplicateAddressDetectionState is DuplicateAddressDetectionState.Tentative or DuplicateAddressDetectionState.Duplicate);
+        }
+        catch (PlatformNotSupportedException)
+        {
+            return false;
+        }
+    }
+
+    private static string? Read(string path)
+    {
+        try
+        {
+            return File.Exists(path) ? File.ReadAllText(path) : null;
+        }
+        catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
+        {
+            return null;
+        }
+    }
+}