fix: support rootless ICMP and verify SELinux deployment [CI]

backend/shared/MoShiro.Measurement/Blocks/Session.cs

@@ -1,6 +1,7 @@
 using System.Net.NetworkInformation;
 using System.Net.Sockets;
 using System.Security.Authentication;
+using Fleet.Core;
 using MoShiro.Protocol;
 
 namespace MoShiro.Measurement;
@@ -306,7 +307,8 @@ public sealed class IcmpEchoSolo : BlockBase
         TimeSpan interval = TimeSpan.FromSeconds(1.0 / Spec.Int("rate_hz"));
         int size = (int)Spec.Int("size");
         byte[] payload = new byte[Math.Max(0, size - 28)];
-        using var ping = new Ping();
+        using LinuxIcmpEcho? linuxPing = OperatingSystem.IsLinux() ? LinuxIcmpEcho.TryCreate(Env.PeerAddress!, payload.Length) : null;
+        using Ping? ping = linuxPing is null ? new Ping() : null;
         try
         {
             while (!ct.IsCancellationRequested)
@@ -315,8 +317,10 @@ public sealed class IcmpEchoSolo : BlockBase
                 long? t4 = null;
                 try
                 {
-                    PingReply reply = await ping.SendPingAsync(Env.PeerAddress!, TimeSpan.FromSeconds(2), payload, null, ct);
-                    if (reply.Status == IPStatus.Success)
+                    bool receivedReply = linuxPing is not null
+                        ? await linuxPing.SendAsync(TimeSpan.FromSeconds(2), ct)
+                        : (await ping!.SendPingAsync(Env.PeerAddress!, TimeSpan.FromSeconds(2), payload, null, ct)).Status == IPStatus.Success;
+                    if (receivedReply)
                     {
                         t4 = Env.Clock.NowUs();
                     }
@@ -325,6 +329,11 @@ public sealed class IcmpEchoSolo : BlockBase
                 {
                     // 发送失败（例如本机没有路由）：记为丢失
                 }
+                catch (PlatformNotSupportedException) when (OperatingSystem.IsLinux())
+                {
+                    Env.Log.Warn("ICMP permission unavailable", ("hint", "allow the mapped process GID in net.ipv4.ping_group_range, or grant effective NET_RAW"));
+                    throw;
+                }
 
                 long key = _log.Store.Append();
                 _log.Store.Set(key, _seq, key);