capture: add metadata packet

GZTimeWalker · Aug 19, 2023 · 73cdc9a · 73cdc9a
1 parent 3f5f964
commit 73cdc9a
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Showing 6 changed files with 79 additions and 41 deletions.
diff --git a/src/GZCTF/Controllers/ProxyController.cs b/src/GZCTF/Controllers/ProxyController.cs
@@ -1,6 +1,7 @@
 using System.Net;
 using System.Net.Sockets;
 using System.Net.WebSockets;
+using System.Text.Json;
 using GZCTF.Models.Internal;
 using GZCTF.Repositories.Interface;
 using GZCTF.Utils;
@@ -25,6 +26,10 @@ public class ProxyController : ControllerBase
     private readonly bool _enableTrafficCapture = false;
     private const int BUFFER_SIZE = 1024 * 4;
     private const uint CONNECTION_LIMIT = 64;
+    private readonly JsonSerializerOptions _JsonOptions = new()
+    {
+        Encoder = System.Text.Encodings.Web.JavaScriptEncoder.UnsafeRelaxedJsonEscaping
+    };
 
     public ProxyController(ILogger<ProxyController> logger, IDistributedCache cache,
         IOptions<ContainerProvider> provider, IContainerRepository containerRepository)
@@ -60,7 +65,7 @@ public async Task<IActionResult> ProxyForInstance(string id, CancellationToken t
         if (!await IncrementConnectionCount(id))
             return BadRequest(new RequestResponse("容器连接数已达上限"));
 
-        var container = await _containerRepository.GetContainerById(id, token);
+        var container = await _containerRepository.GetContainerWithInstanceById(id, token);
 
         if (container is null || container.Instance is null || !container.IsProxy)
             return NotFound(new RequestResponse("不存在的容器"));
@@ -76,6 +81,24 @@ public async Task<IActionResult> ProxyForInstance(string id, CancellationToken t
         if (clientIp is null)
             return BadRequest(new RequestResponse("无效的访问地址"));
 
+        var enable = _enableTrafficCapture && container.Instance.Challenge.EnableTrafficCapture;
+        byte[]? metadata = null;
+
+        if (enable)
+        {
+            metadata = JsonSerializer.SerializeToUtf8Bytes(new
+            {
+                Challenge = container.Instance.Challenge.Title,
+                container.Instance.ChallengeId,
+
+                Team = container.Instance.Participation.Team.Name,
+                container.Instance.Participation.TeamId,
+
+                container.ContainerId,
+                container.Instance.FlagContext?.Flag
+            }, _JsonOptions);
+        }
+
         CapturableNetworkStream? stream;
         try
         {
@@ -89,13 +112,15 @@ public async Task<IActionResult> ProxyForInstance(string id, CancellationToken t
                 return BadRequest(new RequestResponse("容器连接失败"));
             }
 
-            stream = new CapturableNetworkStream(socket, new()
-            {
-                Source = new(clientIp, clientPort),
-                Dest = ipEndPoint,
-                EnableCapture = _enableTrafficCapture && container.Instance.Challenge.EnableTrafficCapture,
-                FilePath = container.TrafficPath(HttpContext.Connection.Id),
-            });
+            stream = new CapturableNetworkStream(socket, metadata,
+                new()
+                {
+                    Source = new(clientIp, clientPort),
+                    Dest = ipEndPoint,
+                    EnableCapture = enable,
+                    FilePath = container.TrafficPath(HttpContext.Connection.Id),
+                }
+            );
         }
         catch (Exception e)
         {

diff --git a/src/GZCTF/Repositories/ContainerRepository.cs b/src/GZCTF/Repositories/ContainerRepository.cs
@@ -19,8 +19,13 @@ public ContainerRepository(IDistributedCache cache,
     public override Task<int> CountAsync(CancellationToken token = default) => _context.Containers.CountAsync(token);
 
     public Task<Container?> GetContainerById(string guid, CancellationToken token = default)
-        => _context.Containers.Include(c => c.Instance)
-            .ThenInclude(i => i!.Challenge)
+        => _context.Containers.FirstOrDefaultAsync(i => i.Id == guid, token);
+
+    public Task<Container?> GetContainerWithInstanceById(string guid, CancellationToken token = default)
+        => _context.Containers.IgnoreAutoIncludes()
+            .Include(c => c.Instance).ThenInclude(i => i!.Challenge)
+            .Include(c => c.Instance).ThenInclude(i => i!.FlagContext)
+            .Include(c => c.Instance).ThenInclude(i => i!.Participation).ThenInclude(p => p.Team)
             .FirstOrDefaultAsync(i => i.Id == guid, token);
 
     public Task<List<Container>> GetContainers(CancellationToken token = default)

diff --git a/src/GZCTF/Repositories/Interface/IContainerRepository.cs b/src/GZCTF/Repositories/Interface/IContainerRepository.cs
@@ -19,6 +19,14 @@ public interface IContainerRepository : IRepository
     /// <returns></returns>
     public Task<Container?> GetContainerById(string guid, CancellationToken token = default);
 
+    /// <summary>
+    /// 根据容器数据库 ID 获取容器及实例信息
+    /// </summary>
+    /// <param name="guid">容器数据库 ID</param>
+    /// <param name="token"></param>
+    /// <returns></returns>
+    public Task<Container?> GetContainerWithInstanceById(string guid, CancellationToken token = default);
+
     /// <summary>
     /// 容器数据库 ID 对应容器是否存在
     /// </summary>

diff --git a/src/GZCTF/Utils/CapturableNetworkStream.cs b/src/GZCTF/Utils/CapturableNetworkStream.cs
@@ -39,8 +39,9 @@ public sealed class CapturableNetworkStream : NetworkStream
     private readonly CapturableNetworkStreamOptions _options;
     private readonly CaptureFileWriterDevice? _device = null;
     private readonly PhysicalAddress _dummyPhysicalAddress = PhysicalAddress.Parse("00-11-00-11-00-11");
+    private readonly IPEndPoint _host = new(IPAddress.Parse("0.0.0.0"), 65535);
 
-    public CapturableNetworkStream(Socket socket, CapturableNetworkStreamOptions options) : base(socket)
+    public CapturableNetworkStream(Socket socket, byte[]? metadata, CapturableNetworkStreamOptions options) : base(socket)
     {
         _options = options;
 
@@ -55,6 +56,9 @@ public CapturableNetworkStream(Socket socket, CapturableNetworkStreamOptions opt
 
             _device = new(_options.FilePath, FileMode.Open);
             _device.Open(LinkLayers.Ethernet);
+
+            if (metadata is not null)
+                WriteCapturedData(_host, _options.Source, metadata);
         }
     }
 
@@ -65,43 +69,40 @@ public override async ValueTask<int> ReadAsync(Memory<byte> buffer, Cancellation
         if (!_options.EnableCapture)
             return count;
 
-        var udp = new UdpPacket((ushort)_options.Dest.Port, (ushort)_options.Source.Port)
-        {
-            PayloadDataSegment = new ByteArraySegment(buffer[..count].ToArray())
-        };
-
-        var packet = new EthernetPacket(_dummyPhysicalAddress, _dummyPhysicalAddress, EthernetType.IPv6)
-        {
-            PayloadPacket = new IPv6Packet(_options.Dest.Address, _options.Source.Address) { PayloadPacket = udp }
-        };
-
-        udp.UpdateUdpChecksum();
-
-        _device?.Write(new RawCapture(LinkLayers.Ethernet, new(), packet.Bytes));
+        WriteCapturedData(_options.Dest, _options.Source, buffer);
 
         return count;
     }
 
     public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
     {
         if (_options.EnableCapture)
-        {
-            var udp = new UdpPacket((ushort)_options.Source.Port, (ushort)_options.Dest.Port)
-            {
-                PayloadDataSegment = new ByteArraySegment(buffer.ToArray())
-            };
+            WriteCapturedData(_options.Source, _options.Dest, buffer);
 
-            var packet = new EthernetPacket(_dummyPhysicalAddress, _dummyPhysicalAddress, EthernetType.IPv6)
-            {
-                PayloadPacket = new IPv6Packet(_options.Source.Address, _options.Dest.Address) { PayloadPacket = udp }
-            };
+        await base.WriteAsync(buffer, cancellationToken);
+    }
 
-            udp.UpdateUdpChecksum();
+    /// <summary>
+    /// 向文件写入一条数据记录
+    /// </summary>
+    /// <param name="source">源地址</param>
+    /// <param name="dest">目的地址</param>
+    /// <param name="buffer">数据</param>
+    internal void WriteCapturedData(IPEndPoint source, IPEndPoint dest, ReadOnlyMemory<byte> buffer)
+    {
+        var udp = new UdpPacket((ushort)source.Port, (ushort)dest.Port)
+        {
+            PayloadDataSegment = new ByteArraySegment(buffer.ToArray())
+        };
 
-            _device?.Write(new RawCapture(LinkLayers.Ethernet, new(), packet.Bytes));
-        }
+        var packet = new EthernetPacket(_dummyPhysicalAddress, _dummyPhysicalAddress, EthernetType.IPv6)
+        {
+            PayloadPacket = new IPv6Packet(source.Address, dest.Address) { PayloadPacket = udp }
+        };
 
-        await base.WriteAsync(buffer, cancellationToken);
+        udp.UpdateUdpChecksum();
+
+        _device?.Write(new RawCapture(LinkLayers.Ethernet, new(), packet.Bytes));
     }
 
     public override void Close()

diff --git a/src/GZCTF/Utils/HubHelper.cs b/src/GZCTF/Utils/HubHelper.cs
@@ -3,7 +3,7 @@
 
 namespace GZCTF.Utils;
 
-public class HubHelper
+public static class HubHelper
 {
     /// <summary>
     /// 当前请求是否具有权限

diff --git a/src/GZCTF/Utils/LogHelper.cs b/src/GZCTF/Utils/LogHelper.cs
@@ -3,7 +3,6 @@
 using GZCTF.Extensions;
 using NpgsqlTypes;
 using Serilog;
-using Serilog.Core;
 using Serilog.Events;
 using Serilog.Sinks.File.Archive;
 using Serilog.Sinks.PostgreSQL;
@@ -138,14 +137,14 @@ public static Serilog.ILogger GetLogger(IConfiguration configuration, IServicePr
                 restrictedToMinimumLevel: LogEventLevel.Debug
             ))
             .WriteTo.Async(t => t.File(
-                path: $"files/logs/log_.log",
+                path: $"{FilePath.Logs}/log_.log",
                 formatter: new ExpressionTemplate(LogTemplate),
                 rollingInterval: RollingInterval.Day,
                 fileSizeLimitBytes: 10 * 1024 * 1024,
                 restrictedToMinimumLevel: LogEventLevel.Debug,
                 rollOnFileSizeLimit: true,
                 retainedFileCountLimit: 5,
-                hooks: new ArchiveHooks(CompressionLevel.Optimal, "files/logs/archive/{UtcDate:yyyy-MM}")
+                hooks: new ArchiveHooks(CompressionLevel.Optimal, $"{FilePath.Logs}/archive/{{UtcDate:yyyy-MM}}")
             ))
             .WriteTo.Async(t => t.PostgreSQL(
                 connectionString: configuration.GetConnectionString("Database"),