feat: port checker prototype (#1938)

* feat: port checker prototype

* fix: automatically unmap IPv6-mapped IPv4 on error

* feat: port checker service behind proxy

* chore: additional log line

* chore: cleaned up server api KnownProxies impl

.dockerignore

@@ -0,0 +1,25 @@
+**/.dockerignore
+**/.env
+**/.git
+**/.gitignore
+**/.project
+**/.settings
+**/.toolstarget
+**/.vs
+**/.vscode
+**/.idea
+**/*.*proj.user
+**/*.dbmdl
+**/*.jfm
+**/azds.yaml
+**/bin
+**/charts
+**/docker-compose*
+**/Dockerfile*
+**/node_modules
+**/npm-debug.log
+**/obj
+**/secrets.dev.yaml
+**/values.dev.yaml
+LICENSE
+README.md

.editorconfig

@@ -96,7 +96,7 @@ csharp_style_pattern_matching_over_as_with_null_check = true:suggestion
 csharp_style_throw_expression = true:suggestion
 csharp_style_conditional_delegate_call = true:suggestion
 # Modifier preferences
-csharp_preferred_modifier_order = public,private,protected,internal,static,extern,new,virtual,abstract,sealed,override,readonly,unsafe,volatile,async:suggestion
+csharp_preferred_modifier_order = public, private, protected, internal, static, extern, new, virtual, abstract, sealed, override, readonly, unsafe, volatile, async:suggestion
 # Expression-level preferences
 csharp_prefer_braces = true:silent
 csharp_style_deconstructed_variable_declaration = true:suggestion
@@ -143,4 +143,4 @@ resharper_trailing_comma_in_multiline_lists = true
 ###############################
 [*.vb]
 # Modifier preferences
-visual_basic_preferred_modifier_order = Partial,Default,Private,Protected,Public,Friend,NotOverridable,Overridable,MustOverride,Overloads,Overrides,MustInherit,NotInheritable,Static,Shared,Shadows,ReadOnly,WriteOnly,Dim,Const,WithEvents,Widening,Narrowing,Custom,Async:suggestion
+visual_basic_preferred_modifier_order = Partial, Default, Private, Protected, Public, Friend, NotOverridable, Overridable, MustOverride, Overloads, Overrides, MustInherit, NotInheritable, Static, Shared, Shadows, ReadOnly, WriteOnly, Dim, Const, WithEvents, Widening, Narrowing, Custom, Async:suggestion

Directory.Build.props

@@ -4,7 +4,7 @@
     <IntersectRepoPath Condition="'$(IntersectRepoPath)' == ''">$(MSBuildProjectDirectory)\..</IntersectRepoPath>
   </PropertyGroup>
 
-  <Import Project=".\Intersect.props" />
+  <Import Project=".\Intersect.props"/>
 
   <PropertyGroup>
     <IntersectProjectName>$(MSBuildProjectName.Substring(10))</IntersectProjectName>

Intersect (Core)/Config/Options.cs

@@ -29,6 +29,9 @@ public partial class Options
         [JsonProperty("OpenPortChecker", Order = 0)]
         protected bool _portChecker = true;
 
+        [JsonProperty(NullValueHandling = NullValueHandling.Include)]
+        public string? PortCheckerUrl { get; set; }
+
         [JsonProperty("MaxClientConnections")]
         public int MaxClientConnections { get; set; }= 100;
 

Intersect (Core)/Network/INetworkLayerInterface.cs

@@ -35,6 +35,8 @@ bool SendPacket(
             TransmissionMode transmissionMode = TransmissionMode.All
         );
 
+        bool SendUnconnectedPacket(IPEndPoint target, ReadOnlySpan<byte> data);
+
         bool SendUnconnectedPacket(IPEndPoint target, UnconnectedPacket packet);
 
         void Start();

Intersect (Core)/Network/UnconnectedMessageSender.cs

@@ -8,5 +8,7 @@ public sealed record UnconnectedMessageSender(
     object? InterfaceMetadata
 )
 {
+    public void Reply(ReadOnlySpan<byte> data) => NetworkInterface.SendUnconnectedPacket(RemoteEndPoint, data);
+
     public void Reply(UnconnectedPacket packet) => NetworkInterface.SendUnconnectedPacket(RemoteEndPoint, packet);
 }

Intersect.Network/Lidgren/LidgrenInterface.cs

@@ -149,6 +149,11 @@ public LidgrenInterface(INetwork network, Type peerType, RSAParameters rsaParame
 
         public bool IsDisposed { get; private set; }
 
+        public bool SendUnconnectedPacket(IPEndPoint target, ReadOnlySpan<byte> data)
+        {
+            throw new NotImplementedException();
+        }
+
         public bool SendUnconnectedPacket(IPEndPoint target, UnconnectedPacket packet)
         {
             throw new NotImplementedException();

Intersect.Network/LiteNetLib/LiteNetLibInterface.cs

@@ -304,6 +304,9 @@ DeliveryMethod deliveryMethod
         OnPacketAvailable?.Invoke(this);
     }
 
+    public bool SendUnconnectedPacket(IPEndPoint target, ReadOnlySpan<byte> data) =>
+        _manager.SendUnconnectedMessage(data.ToArray(), target);
+
     public bool SendUnconnectedPacket(IPEndPoint target, UnconnectedPacket packet)
     {
         using var tempAsymmetric = RSA.Create(_asymmetricServer.ExportParameters(false));
@@ -332,11 +335,17 @@ public bool SendUnconnectedPacket(IPEndPoint target, UnconnectedPacket packet)
         Log.Debug($"{nameof(SendUnconnectedPacket)} {nameof(encryptedPacketData)}({encryptedPacketData.Length})={Convert.ToHexString(encryptedPacketData)}");
 #endif
 
-        var data = NetDataWriter.FromBytes(encryptedPacketData, false);
+        NetDataWriter data = new(false, encryptedPacketData.Length + 1);
+        data.Put((byte)UnconnectedPacketType.AsymmetricEncrypted);
+        data.Put(encryptedPacketData);
         return _manager.SendUnconnectedMessage(data, target);
     }
 
-    public void OnNetworkReceiveUnconnected(IPEndPoint remoteEndPoint, NetPacketReader reader, UnconnectedMessageType messageType)
+    private void HandleAsymmetricEncryptedUnconnectedPacket(
+        IPEndPoint remoteEndPoint,
+        NetDataReader reader,
+        UnconnectedMessageType messageType
+    )
     {
         try
         {
@@ -379,6 +388,41 @@ public void OnNetworkReceiveUnconnected(IPEndPoint remoteEndPoint, NetPacketRead
         }
     }
 
+    public void OnNetworkReceiveUnconnected(IPEndPoint remoteEndPoint, NetPacketReader reader, UnconnectedMessageType messageType)
+    {
+        try
+        {
+            if (!reader.TryGetByte(out var unconnectedPacketTypeAsByte))
+            {
+                return;
+            }
+
+            var unconnectedPacketType = (UnconnectedPacketType)unconnectedPacketTypeAsByte;
+            if (!Enum.IsDefined(typeof(UnconnectedPacketType), unconnectedPacketTypeAsByte))
+            {
+                unconnectedPacketType = UnconnectedPacketType.AsymmetricEncrypted;
+            }
+
+            switch (unconnectedPacketType)
+            {
+                case UnconnectedPacketType.Plaintext:
+                    OnUnconnectedMessage?.Invoke(
+                        new UnconnectedMessageSender(this, remoteEndPoint, default),
+                        new LiteNetLibInboundBuffer(reader)
+                    );
+                    break;
+                case UnconnectedPacketType.AsymmetricEncrypted:
+                    HandleAsymmetricEncryptedUnconnectedPacket(remoteEndPoint, reader, messageType);
+                    break;
+                default: throw new UnreachableException();
+            }
+        }
+        catch (Exception exception)
+        {
+            Log.Debug(exception);
+        }
+    }
+
     public void OnNetworkLatencyUpdate(NetPeer peer, int latency)
     {
         Log.Verbose($"LTNC {peer.EndPoint} {latency}ms");

Intersect.Network/LiteNetLib/UnconnectedPacketType.cs

@@ -0,0 +1,7 @@
+namespace Intersect.Network.LiteNetLib;
+
+public enum UnconnectedPacketType : byte
+{
+    Plaintext = 0,
+    AsymmetricEncrypted,
+}

Intersect.Server/Core/Bootstrapper.cs

@@ -168,7 +168,7 @@ internal static void CheckNetwork()
                     return;
                 }
 
-                if (Options.UPnP)
+                if (Options.UPnP && !Context.StartupOptions.NoNatPunchthrough)
                 {
                     Log.Pretty.Info(Strings.Portchecking.PortNotOpenTryingUPnP.ToString(Options.ServerPort));
                     Console.WriteLine();

Intersect.Server/Core/ServerContext.cs

@@ -272,11 +272,6 @@ private void InternalStartNetworking()
             Console.WriteLine();
 #endif
 
-            if (!Options.UPnP || Instance.StartupOptions.NoNatPunchthrough)
-            {
-                return;
-            }
-
             Bootstrapper.CheckNetwork();
 
             Console.WriteLine();

Intersect.Server/Networking/Helpers/PortCheckResult.cs

@@ -0,0 +1,16 @@
+namespace Intersect.Server.Networking.Helpers;
+
+public enum PortCheckResult
+{
+    Unknown,
+    Open,
+    PossiblyOpen,
+    IntersectResponseNoPlayerCount,
+    IntersectResponseInvalidPlayerCount,
+    InvalidPortCheckerRequest,
+    InvalidPortCheckerResponse,
+    PortCheckerServerError,
+    PortCheckerServerDown,
+    PortCheckerServerUnexpectedResponse,
+    Inaccessible,
+}