Directory.Packages.props

@@ -33,6 +33,7 @@
     <PackageVersion Include="OpenTK.Graphics" Version="4.8.2" />
     <PackageVersion Include="OpenTK.Audio.OpenAL" Version="4.8.2" />
     <PackageVersion Include="OpenTK.Windowing.GraphicsLibraryFramework" Version="4.8.2" />
+    <PackageVersion Include="Open.NAT.Core" Version="2.1.0.5" />
     <PackageVersion Include="Ryujinx.Audio.OpenAL.Dependencies" Version="1.21.0.1" />
     <PackageVersion Include="Ryujinx.Graphics.Nvdec.Dependencies" Version="5.0.3-build14" />
     <PackageVersion Include="Ryujinx.Graphics.Vulkan.Dependencies.MoltenVK" Version="1.2.0" />

src/Ryujinx.Common/Configuration/Multiplayer/MultiplayerMode.cs

@@ -3,6 +3,7 @@ namespace Ryujinx.Common.Configuration.Multiplayer
     public enum MultiplayerMode
     {
         Disabled,
+        LdnRyu,
         LdnMitm,
     }
 }

src/Ryujinx.Common/Memory/StructArrayHelpers.cs

@@ -803,18 +803,6 @@ namespace Ryujinx.Common.Memory
         public Span<T> AsSpan() => MemoryMarshal.CreateSpan(ref _e0, Length);
     }
 
-    public struct Array256<T> : IArray<T> where T : unmanaged
-    {
-        T _e0;
-        Array128<T> _other;
-        Array127<T> _other2;
-        public readonly int Length => 256;
-        public ref T this[int index] => ref AsSpan()[index];
-
-        [Pure]
-        public Span<T> AsSpan() => MemoryMarshal.CreateSpan(ref _e0, Length);
-    }
-
     public struct Array140<T> : IArray<T> where T : unmanaged
     {
         T _e0;
@@ -828,6 +816,18 @@ namespace Ryujinx.Common.Memory
         public Span<T> AsSpan() => MemoryMarshal.CreateSpan(ref _e0, Length);
     }
 
+    public struct Array256<T> : IArray<T> where T : unmanaged
+    {
+        T _e0;
+        Array128<T> _other;
+        Array127<T> _other2;
+        public readonly int Length => 256;
+        public ref T this[int index] => ref AsSpan()[index];
+
+        [Pure]
+        public Span<T> AsSpan() => MemoryMarshal.CreateSpan(ref _e0, Length);
+    }
+
     public struct Array384<T> : IArray<T> where T : unmanaged
     {
         T _e0;

src/Ryujinx.Common/Utilities/NetworkHelpers.cs

@@ -1,6 +1,7 @@
 using System.Buffers.Binary;
 using System.Net;
 using System.Net.NetworkInformation;
+using System.Runtime.InteropServices;
 
 namespace Ryujinx.Common.Utilities
 {
@@ -65,6 +66,11 @@ namespace Ryujinx.Common.Utilities
             return (targetProperties, targetAddressInfo);
         }
 
+        public static bool SupportsDynamicDns()
+        {
+            return RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+        }
+
         public static uint ConvertIpv4Address(IPAddress ipAddress)
         {
             return BinaryPrimitives.ReadUInt32BigEndian(ipAddress.GetAddressBytes());

src/Ryujinx.HLE/HLEConfiguration.cs

@@ -164,6 +164,21 @@ namespace Ryujinx.HLE
         /// </summary>
         public MultiplayerMode MultiplayerMode { internal get; set; }
 
+        /// <summary>
+        /// Disable P2P mode
+        /// </summary>
+        public bool MultiplayerDisableP2p { internal get; set; }
+
+        /// <summary>
+        /// Multiplayer Passphrase
+        /// </summary>
+        public string MultiplayerLdnPassphrase { internal get; set; }
+
+        /// <summary>
+        /// LDN Server
+        /// </summary>
+        public string MultiplayerLdnServer { internal get; set; }
+
         /// <summary>
         /// An action called when HLE force a refresh of output after docked mode changed.
         /// </summary>
@@ -194,7 +209,10 @@ namespace Ryujinx.HLE
                                 float audioVolume,
                                 bool useHypervisor,
                                 string multiplayerLanInterfaceId,
-                                MultiplayerMode multiplayerMode)
+                                MultiplayerMode multiplayerMode,
+                                bool multiplayerDisableP2p,
+                                string multiplayerLdnPassphrase,
+                                string multiplayerLdnServer)
         {
             VirtualFileSystem = virtualFileSystem;
             LibHacHorizonManager = libHacHorizonManager;
@@ -222,6 +240,9 @@ namespace Ryujinx.HLE
             UseHypervisor = useHypervisor;
             MultiplayerLanInterfaceId = multiplayerLanInterfaceId;
             MultiplayerMode = multiplayerMode;
+            MultiplayerDisableP2p = multiplayerDisableP2p;
+            MultiplayerLdnPassphrase = multiplayerLdnPassphrase;
+            MultiplayerLdnServer = multiplayerLdnServer;
         }
     }
 }

src/Ryujinx.HLE/HOS/Services/Ldn/Types/NetworkConfig.cs

@@ -3,7 +3,7 @@ using System.Runtime.InteropServices;
 
 namespace Ryujinx.HLE.HOS.Services.Ldn.Types
 {
-    [StructLayout(LayoutKind.Sequential, Size = 0x20)]
+    [StructLayout(LayoutKind.Sequential, Size = 0x20, Pack = 8)]
     struct NetworkConfig
     {
         public IntentId IntentId;

src/Ryujinx.HLE/HOS/Services/Ldn/Types/ScanFilter.cs

@@ -3,7 +3,7 @@ using System.Runtime.InteropServices;
 
 namespace Ryujinx.HLE.HOS.Services.Ldn.Types
 {
-    [StructLayout(LayoutKind.Sequential, Size = 0x60)]
+    [StructLayout(LayoutKind.Sequential, Size = 0x60, Pack = 8)]
     struct ScanFilter
     {
         public NetworkId NetworkId;

src/Ryujinx.HLE/HOS/Services/Ldn/Types/SecurityConfig.cs

@@ -3,7 +3,7 @@ using System.Runtime.InteropServices;
 
 namespace Ryujinx.HLE.HOS.Services.Ldn.Types
 {
-    [StructLayout(LayoutKind.Sequential, Size = 0x44)]
+    [StructLayout(LayoutKind.Sequential, Size = 0x44, Pack = 2)]
     struct SecurityConfig
     {
         public SecurityMode SecurityMode;

src/Ryujinx.HLE/HOS/Services/Ldn/Types/SecurityParameter.cs

@@ -3,7 +3,7 @@ using System.Runtime.InteropServices;
 
 namespace Ryujinx.HLE.HOS.Services.Ldn.Types
 {
-    [StructLayout(LayoutKind.Sequential, Size = 0x20)]
+    [StructLayout(LayoutKind.Sequential, Size = 0x20, Pack = 1)]
     struct SecurityParameter
     {
         public Array16<byte> Data;

src/Ryujinx.HLE/HOS/Services/Ldn/Types/UserConfig.cs

@@ -3,7 +3,7 @@ using System.Runtime.InteropServices;
 
 namespace Ryujinx.HLE.HOS.Services.Ldn.Types
 {
-    [StructLayout(LayoutKind.Sequential, Size = 0x30)]
+    [StructLayout(LayoutKind.Sequential, Size = 0x30, Pack = 1)]
     struct UserConfig
     {
         public Array33<byte> UserName;

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/AccessPoint.cs

@@ -15,6 +15,8 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
         public Array8<NodeLatestUpdate> LatestUpdates = new();
         public bool Connected { get; private set; }
 
+        public ProxyConfig Config => _parent.NetworkClient.Config;
+
         public AccessPoint(IUserLocalCommunicationService parent)
         {
             _parent = parent;
@@ -23,11 +25,14 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
         }
 
         public void Dispose()
+        {
+            if (_parent?.NetworkClient != null)
             {
                 _parent.NetworkClient.DisconnectNetwork();
 
                 _parent.NetworkClient.NetworkChange -= NetworkChanged;
             }
+        }
 
         private void NetworkChanged(object sender, NetworkChangeEventArgs e)
         {

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/INetworkClient.cs

@@ -6,6 +6,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 {
     interface INetworkClient : IDisposable
     {
+        ProxyConfig Config { get; }
         bool NeedsRealId { get; }
 
         event EventHandler<NetworkChangeEventArgs> NetworkChange;

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/IUserLocalCommunicationService.cs

@@ -9,6 +9,8 @@ using Ryujinx.HLE.HOS.Ipc;
 using Ryujinx.HLE.HOS.Kernel.Threading;
 using Ryujinx.HLE.HOS.Services.Ldn.Types;
 using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnMitm;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types;
 using Ryujinx.Horizon.Common;
 using Ryujinx.Memory;
 using System;
@@ -21,6 +23,9 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 {
     class IUserLocalCommunicationService : IpcService, IDisposable
     {
+        public static string DefaultLanPlayHost = "ryuldn.vudjun.com";
+        public static short LanPlayPort = 30456;
+
         public INetworkClient NetworkClient { get; private set; }
 
         private const int NifmRequestID = 90;
@@ -174,6 +179,16 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
             // NOTE: Return ResultCode.InvalidArgument if ip_address and subnet_mask are null, doesn't occur in our case.
 
             if (_state == NetworkState.AccessPointCreated || _state == NetworkState.StationConnected)
+            {
+                ProxyConfig config = _state switch
+                {
+                    NetworkState.AccessPointCreated => _accessPoint.Config,
+                    NetworkState.StationConnected => _station.Config,
+
+                    _ => default
+                };
+
+                if (config.ProxyIp == 0)
                 {
                     (_, UnicastIPAddressInformation unicastAddress) = NetworkHelpers.GetLocalInterface(context.Device.Configuration.MultiplayerLanInterfaceId);
 
@@ -191,6 +206,14 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
                     }
                 }
                 else
+                {
+                    Logger.Info?.Print(LogClass.ServiceLdn, $"LDN obtained proxy IP.");
+
+                    context.ResponseData.Write(config.ProxyIp);
+                    context.ResponseData.Write(config.ProxySubnetMask);
+                }
+            }
+            else
             {
                 return ResultCode.InvalidArgument;
             }
@@ -1066,6 +1089,27 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 
                         switch (mode)
                         {
+                            case MultiplayerMode.LdnRyu:
+                                try
+                                {
+                                    string ldnServer = context.Device.Configuration.MultiplayerLdnServer;
+                                    if (string.IsNullOrEmpty(ldnServer))
+                                    {
+                                        ldnServer = DefaultLanPlayHost;
+                                    }
+                                    if (!IPAddress.TryParse(ldnServer, out IPAddress ipAddress))
+                                    {
+                                        ipAddress = Dns.GetHostEntry(ldnServer).AddressList[0];
+                                    }
+                                    NetworkClient = new LdnMasterProxyClient(ipAddress.ToString(), LanPlayPort, context.Device.Configuration);
+                                }
+                                catch (Exception ex)
+                                {
+                                    Logger.Error?.Print(LogClass.ServiceLdn, "Could not locate LdnRyu server. Defaulting to stubbed wireless.");
+                                    Logger.Error?.Print(LogClass.ServiceLdn, ex.Message);
+                                    NetworkClient = new LdnDisabledClient();
+                                }
+                                break;
                             case MultiplayerMode.LdnMitm:
                                 NetworkClient = new LdnMitmClient(context.Device.Configuration);
                                 break;
@@ -1103,7 +1147,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
             _accessPoint?.Dispose();
             _accessPoint = null;
 
-            NetworkClient?.Dispose();
+            NetworkClient?.DisconnectAndStop();
             NetworkClient = null;
         }
     }

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnDisabledClient.cs

@@ -1,3 +1,4 @@
+using Ryujinx.Common.Logging;
 using Ryujinx.HLE.HOS.Services.Ldn.Types;
 using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types;
 using System;
@@ -6,12 +7,14 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 {
     class LdnDisabledClient : INetworkClient
     {
+        public ProxyConfig Config { get; }
         public bool NeedsRealId => true;
 
         public event EventHandler<NetworkChangeEventArgs> NetworkChange;
 
         public NetworkError Connect(ConnectRequest request)
         {
+            Logger.Warning?.PrintMsg(LogClass.ServiceLdn, "Attempted to connect to a network, but Multiplayer is disabled!");
             NetworkChange?.Invoke(this, new NetworkChangeEventArgs(new NetworkInfo(), false));
 
             return NetworkError.None;
@@ -19,6 +22,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 
         public NetworkError ConnectPrivate(ConnectPrivateRequest request)
         {
+            Logger.Warning?.PrintMsg(LogClass.ServiceLdn, "Attempted to connect to a network, but Multiplayer is disabled!");
             NetworkChange?.Invoke(this, new NetworkChangeEventArgs(new NetworkInfo(), false));
 
             return NetworkError.None;
@@ -26,6 +30,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 
         public bool CreateNetwork(CreateAccessPointRequest request, byte[] advertiseData)
         {
+            Logger.Warning?.PrintMsg(LogClass.ServiceLdn, "Attempted to create a network, but Multiplayer is disabled!");
             NetworkChange?.Invoke(this, new NetworkChangeEventArgs(new NetworkInfo(), false));
 
             return true;
@@ -33,6 +38,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 
         public bool CreateNetworkPrivate(CreateAccessPointPrivateRequest request, byte[] advertiseData)
         {
+            Logger.Warning?.PrintMsg(LogClass.ServiceLdn, "Attempted to create a network, but Multiplayer is disabled!");
             NetworkChange?.Invoke(this, new NetworkChangeEventArgs(new NetworkInfo(), false));
 
             return true;
@@ -49,6 +55,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 
         public NetworkInfo[] Scan(ushort channel, ScanFilter scanFilter)
         {
+            Logger.Warning?.PrintMsg(LogClass.ServiceLdn, "Attempted to scan for networks, but Multiplayer is disabled!");
             return Array.Empty<NetworkInfo>();
         }
 

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnMitm/LdnMitmClient.cs

@@ -12,6 +12,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnMitm
     /// </summary>
     internal class LdnMitmClient : INetworkClient
     {
+        public ProxyConfig Config { get; }
         public bool NeedsRealId => false;
 
         public event EventHandler<NetworkChangeEventArgs> NetworkChange;

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/IProxyClient.cs

@@ -0,0 +1,7 @@
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu
+{
+    interface IProxyClient
+    {
+        bool SendAsync(byte[] buffer);
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/LdnMasterProxyClient.cs

@@ -0,0 +1,645 @@
+using Ryujinx.Common.Logging;
+using Ryujinx.Common.Utilities;
+using Ryujinx.HLE.HOS.Services.Ldn.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types;
+using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy;
+using Ryujinx.HLE.Utilities;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.NetworkInformation;
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using TcpClient = NetCoreServer.TcpClient;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu
+{
+    class LdnMasterProxyClient : TcpClient, INetworkClient, IProxyClient
+    {
+        public bool NeedsRealId => true;
+
+        private static InitializeMessage InitializeMemory = new InitializeMessage();
+
+        private const int InactiveTimeout = 6000;
+        private const int FailureTimeout = 4000;
+        private const int ScanTimeout = 1000;
+
+        private bool _useP2pProxy;
+        private NetworkError _lastError;
+
+        private readonly ManualResetEvent _connected = new ManualResetEvent(false);
+        private readonly ManualResetEvent _error = new ManualResetEvent(false);
+        private readonly ManualResetEvent _scan = new ManualResetEvent(false);
+        private readonly ManualResetEvent _reject = new ManualResetEvent(false);
+        private readonly AutoResetEvent _apConnected = new AutoResetEvent(false);
+
+        private readonly RyuLdnProtocol _protocol;
+        private readonly NetworkTimeout _timeout;
+
+        private readonly List<NetworkInfo> _availableGames = new List<NetworkInfo>();
+        private DisconnectReason _disconnectReason;
+
+        private P2pProxyServer _hostedProxy;
+        private P2pProxyClient _connectedProxy;
+
+        private bool _networkConnected;
+
+        private string _passphrase;
+        private byte[] _gameVersion = new byte[0x10];
+
+        private readonly HLEConfiguration _config;
+
+        public event EventHandler<NetworkChangeEventArgs> NetworkChange;
+
+        public ProxyConfig Config { get; private set; }
+
+        public LdnMasterProxyClient(string address, int port, HLEConfiguration config) : base(address, port)
+        {
+            if (ProxyHelpers.SupportsNoDelay())
+            {
+                OptionNoDelay = true;
+            }
+
+            _protocol = new RyuLdnProtocol();
+            _timeout = new NetworkTimeout(InactiveTimeout, TimeoutConnection);
+
+            _protocol.Initialize += HandleInitialize;
+            _protocol.Connected += HandleConnected;
+            _protocol.Reject += HandleReject;
+            _protocol.RejectReply += HandleRejectReply;
+            _protocol.SyncNetwork += HandleSyncNetwork;
+            _protocol.ProxyConfig += HandleProxyConfig;
+            _protocol.Disconnected += HandleDisconnected;
+
+            _protocol.ScanReply += HandleScanReply;
+            _protocol.ScanReplyEnd += HandleScanReplyEnd;
+            _protocol.ExternalProxy += HandleExternalProxy;
+
+            _protocol.Ping += HandlePing;
+            _protocol.NetworkError += HandleNetworkError;
+
+            _config = config;
+            _useP2pProxy = !config.MultiplayerDisableP2p;
+        }
+
+        private void TimeoutConnection()
+        {
+            _connected.Reset();
+
+            DisconnectAsync();
+
+            while (IsConnected)
+            {
+                Thread.Yield();
+            }
+        }
+
+        private bool EnsureConnected()
+        {
+            if (IsConnected)
+            {
+                return true;
+            }
+
+            _error.Reset();
+
+            ConnectAsync();
+
+            int index = WaitHandle.WaitAny(new WaitHandle[] { _connected, _error }, FailureTimeout);
+
+            if (IsConnected)
+            {
+                SendAsync(_protocol.Encode(PacketId.Initialize, InitializeMemory));
+            }
+
+            return index == 0 && IsConnected;
+        }
+
+        private void UpdatePassphraseIfNeeded()
+        {
+            string passphrase = _config.MultiplayerLdnPassphrase ?? "";
+            if (passphrase != _passphrase)
+            {
+                _passphrase = passphrase;
+
+                SendAsync(_protocol.Encode(PacketId.Passphrase, StringUtils.GetFixedLengthBytes(passphrase, 0x80, Encoding.UTF8)));
+            }
+        }
+
+        protected override void OnConnected()
+        {
+            Logger.Info?.PrintMsg(LogClass.ServiceLdn, $"LDN TCP client connected a new session with Id {Id}");
+
+            UpdatePassphraseIfNeeded();
+
+            _connected.Set();
+        }
+
+        protected override void OnDisconnected()
+        {
+            Logger.Info?.PrintMsg(LogClass.ServiceLdn, $"LDN TCP client disconnected a session with Id {Id}");
+
+            _passphrase = null;
+
+            _connected.Reset();
+
+            if (_networkConnected)
+            {
+                DisconnectInternal();
+            }
+        }
+
+        public void DisconnectAndStop()
+        {
+            _timeout.Dispose();
+
+            DisconnectAsync();
+
+            while (IsConnected)
+            {
+                Thread.Yield();
+            }
+
+            Dispose();
+        }
+
+        protected override void OnReceived(byte[] buffer, long offset, long size)
+        {
+            _protocol.Read(buffer, (int)offset, (int)size);
+        }
+
+        protected override void OnError(SocketError error)
+        {
+            Logger.Info?.PrintMsg(LogClass.ServiceLdn, $"LDN TCP client caught an error with code {error}");
+
+            _error.Set();
+        }
+
+
+
+        private void HandleInitialize(LdnHeader header, InitializeMessage initialize)
+        {
+            InitializeMemory = initialize;
+        }
+
+        private void HandleExternalProxy(LdnHeader header, ExternalProxyConfig config)
+        {
+            int length = config.AddressFamily switch
+            {
+                AddressFamily.InterNetwork => 4,
+                AddressFamily.InterNetworkV6 => 16,
+                _ => 0
+            };
+
+            if (length == 0)
+            {
+                return; // Invalid external proxy.
+            }
+
+            IPAddress address = new(config.ProxyIp.AsSpan()[..length].ToArray());
+            P2pProxyClient proxy = new(address.ToString(), config.ProxyPort);
+
+            _connectedProxy = proxy;
+
+            bool success = proxy.PerformAuth(config);
+
+            if (!success)
+            {
+                DisconnectInternal();
+            }
+        }
+
+        private void HandlePing(LdnHeader header, PingMessage ping)
+        {
+            if (ping.Requester == 0) // Server requested.
+            {
+                // Send the ping message back.
+
+                SendAsync(_protocol.Encode(PacketId.Ping, ping));
+            }
+        }
+
+        private void HandleNetworkError(LdnHeader header, NetworkErrorMessage error)
+        {
+            if (error.Error == NetworkError.PortUnreachable)
+            {
+                _useP2pProxy = false;
+            }
+            else
+            {
+                _lastError = error.Error;
+            }
+        }
+
+        private NetworkError ConsumeNetworkError()
+        {
+            NetworkError result = _lastError;
+
+            _lastError = NetworkError.None;
+
+            return result;
+        }
+
+        private void HandleSyncNetwork(LdnHeader header, NetworkInfo info)
+        {
+            NetworkChange?.Invoke(this, new NetworkChangeEventArgs(info, true));
+        }
+
+        private void HandleConnected(LdnHeader header, NetworkInfo info)
+        {
+            _networkConnected = true;
+            _disconnectReason = DisconnectReason.None;
+
+            _apConnected.Set();
+
+            NetworkChange?.Invoke(this, new NetworkChangeEventArgs(info, true));
+        }
+
+        private void HandleDisconnected(LdnHeader header, DisconnectMessage message)
+        {
+            DisconnectInternal();
+        }
+
+        private void HandleReject(LdnHeader header, RejectRequest reject)
+        {
+            // When the client receives a Reject request, we have been rejected and will be disconnected shortly.
+            _disconnectReason = reject.DisconnectReason;
+        }
+
+        private void HandleRejectReply(LdnHeader header)
+        {
+            _reject.Set();
+        }
+
+        private void HandleScanReply(LdnHeader header, NetworkInfo info)
+        {
+            _availableGames.Add(info);
+        }
+
+        private void HandleScanReplyEnd(LdnHeader obj)
+        {
+            _scan.Set();
+        }
+
+        private void DisconnectInternal()
+        {
+            if (_networkConnected)
+            {
+                _networkConnected = false;
+
+                _hostedProxy?.Dispose();
+                _hostedProxy = null;
+
+                _connectedProxy?.Dispose();
+                _connectedProxy = null;
+
+                _apConnected.Reset();
+
+                NetworkChange?.Invoke(this, new NetworkChangeEventArgs(new NetworkInfo(), false, _disconnectReason));
+
+                if (IsConnected)
+                {
+                    _timeout.RefreshTimeout();
+                }
+            }
+        }
+
+        public void DisconnectNetwork()
+        {
+            if (_networkConnected)
+            {
+                SendAsync(_protocol.Encode(PacketId.Disconnect, new DisconnectMessage()));
+
+                DisconnectInternal();
+            }
+        }
+
+        public ResultCode Reject(DisconnectReason disconnectReason, uint nodeId)
+        {
+            if (_networkConnected)
+            {
+                _reject.Reset();
+
+                SendAsync(_protocol.Encode(PacketId.Reject, new RejectRequest(disconnectReason, nodeId)));
+
+                int index = WaitHandle.WaitAny(new WaitHandle[] { _reject, _error }, InactiveTimeout);
+
+                if (index == 0)
+                {
+                    return (ConsumeNetworkError() != NetworkError.None) ? ResultCode.InvalidState : ResultCode.Success;
+                }
+            }
+
+            return ResultCode.InvalidState;
+        }
+
+        public void SetAdvertiseData(byte[] data)
+        {
+            // TODO: validate we're the owner (the server will do this anyways tho)
+            if (_networkConnected)
+            {
+                SendAsync(_protocol.Encode(PacketId.SetAdvertiseData, data));
+            }
+        }
+
+        public void SetGameVersion(byte[] versionString)
+        {
+            _gameVersion = versionString;
+
+            if (_gameVersion.Length < 0x10)
+            {
+                Array.Resize(ref _gameVersion, 0x10);
+            }
+        }
+
+        public void SetStationAcceptPolicy(AcceptPolicy acceptPolicy)
+        {
+            // TODO: validate we're the owner (the server will do this anyways tho)
+            if (_networkConnected)
+            {
+                SendAsync(_protocol.Encode(PacketId.SetAcceptPolicy, new SetAcceptPolicyRequest
+                {
+                    StationAcceptPolicy = acceptPolicy
+                }));
+            }
+        }
+
+        private void DisposeProxy()
+        {
+            _hostedProxy?.Dispose();
+            _hostedProxy = null;
+        }
+
+        private void ConfigureAccessPoint(ref RyuNetworkConfig request)
+        {
+            _gameVersion.AsSpan().CopyTo(request.GameVersion.AsSpan());
+
+            if (_useP2pProxy)
+            {
+                // Before sending the request, attempt to set up a proxy server.
+                // This can be on a range of private ports, which can be exposed on a range of public
+                // ports via UPnP. If any of this fails, we just fall back to using the master server.
+
+                int i = 0;
+                for (; i < P2pProxyServer.PrivatePortRange; i++)
+                {
+                    _hostedProxy = new P2pProxyServer(this, (ushort)(P2pProxyServer.PrivatePortBase + i), _protocol);
+
+                    try
+                    {
+                        _hostedProxy.Start();
+
+                        break;
+                    }
+                    catch (SocketException e)
+                    {
+                        _hostedProxy.Dispose();
+                        _hostedProxy = null;
+
+                        if (e.SocketErrorCode != SocketError.AddressAlreadyInUse)
+                        {
+                            i = P2pProxyServer.PrivatePortRange; // Immediately fail.
+                        }
+                    }
+                }
+
+                bool openSuccess = i < P2pProxyServer.PrivatePortRange;
+
+                if (openSuccess)
+                {
+                    Task<ushort> natPunchResult = _hostedProxy.NatPunch();
+
+                    try
+                    {
+                        if (natPunchResult.Result != 0)
+                        {
+                            // Tell the server that we are hosting the proxy.
+                            request.ExternalProxyPort = natPunchResult.Result;
+                        }
+                    }
+                    catch (Exception) { }
+
+                    if (request.ExternalProxyPort == 0)
+                    {
+                        Logger.Warning?.Print(LogClass.ServiceLdn, "Failed to open a port with UPnP for P2P connection. Proxying through the master server instead. Expect higher latency.");
+                        _hostedProxy.Dispose();
+                    }
+                    else
+                    {
+                        Logger.Info?.Print(LogClass.ServiceLdn, $"Created a wireless P2P network on port {request.ExternalProxyPort}.");
+                        _hostedProxy.Start();
+
+                        (_, UnicastIPAddressInformation unicastAddress) = NetworkHelpers.GetLocalInterface();
+
+                        unicastAddress.Address.GetAddressBytes().AsSpan().CopyTo(request.PrivateIp.AsSpan());
+                        request.InternalProxyPort = _hostedProxy.PrivatePort;
+                        request.AddressFamily = unicastAddress.Address.AddressFamily;
+                    }
+                }
+                else
+                {
+                    Logger.Warning?.Print(LogClass.ServiceLdn, "Cannot create a P2P server. Proxying through the master server instead. Expect higher latency.");
+                }
+            }
+        }
+
+        private bool CreateNetworkCommon()
+        {
+            bool signalled = _apConnected.WaitOne(FailureTimeout);
+
+            if (!_useP2pProxy && _hostedProxy != null)
+            {
+                Logger.Warning?.Print(LogClass.ServiceLdn, "Locally hosted proxy server was not externally reachable. Proxying through the master server instead. Expect higher latency.");
+
+                DisposeProxy();
+            }
+
+            if (signalled && _connectedProxy != null)
+            {
+                _connectedProxy.EnsureProxyReady();
+
+                Config = _connectedProxy.ProxyConfig;
+            }
+            else
+            {
+                DisposeProxy();
+            }
+
+            return signalled;
+        }
+
+        public bool CreateNetwork(CreateAccessPointRequest request, byte[] advertiseData)
+        {
+            _timeout.DisableTimeout();
+
+            ConfigureAccessPoint(ref request.RyuNetworkConfig);
+
+            if (!EnsureConnected())
+            {
+                DisposeProxy();
+
+                return false;
+            }
+
+            UpdatePassphraseIfNeeded();
+
+            SendAsync(_protocol.Encode(PacketId.CreateAccessPoint, request, advertiseData));
+
+            // Send a network change event with dummy data immediately. Necessary to avoid crashes in some games
+            var networkChangeEvent = new NetworkChangeEventArgs(new NetworkInfo()
+            {
+                Common = new CommonNetworkInfo()
+                {
+                    MacAddress = InitializeMemory.MacAddress,
+                    Channel = request.NetworkConfig.Channel,
+                    LinkLevel = 3,
+                    NetworkType = 2,
+                    Ssid = new Ssid()
+                    {
+                        Length = 32
+                    }
+                },
+                Ldn = new LdnNetworkInfo()
+                {
+                    AdvertiseDataSize = (ushort)advertiseData.Length,
+                    AuthenticationId = 0,
+                    NodeCount = 1,
+                    NodeCountMax = request.NetworkConfig.NodeCountMax,
+                    SecurityMode = (ushort)request.SecurityConfig.SecurityMode
+                }
+            }, true);
+            networkChangeEvent.Info.Ldn.Nodes[0] = new NodeInfo()
+            {
+                Ipv4Address = 175243265,
+                IsConnected = 1,
+                LocalCommunicationVersion = request.NetworkConfig.LocalCommunicationVersion,
+                MacAddress = InitializeMemory.MacAddress,
+                NodeId = 0,
+                UserName = request.UserConfig.UserName
+            };
+            "12345678123456781234567812345678"u8.ToArray().CopyTo(networkChangeEvent.Info.Common.Ssid.Name.AsSpan());
+            NetworkChange?.Invoke(this, networkChangeEvent);
+
+            return CreateNetworkCommon();
+        }
+
+        public bool CreateNetworkPrivate(CreateAccessPointPrivateRequest request, byte[] advertiseData)
+        {
+            _timeout.DisableTimeout();
+
+            ConfigureAccessPoint(ref request.RyuNetworkConfig);
+
+            if (!EnsureConnected())
+            {
+                DisposeProxy();
+
+                return false;
+            }
+
+            UpdatePassphraseIfNeeded();
+
+            SendAsync(_protocol.Encode(PacketId.CreateAccessPointPrivate, request, advertiseData));
+
+            return CreateNetworkCommon();
+        }
+
+        public NetworkInfo[] Scan(ushort channel, ScanFilter scanFilter)
+        {
+            if (!_networkConnected)
+            {
+                _timeout.RefreshTimeout();
+            }
+
+            _availableGames.Clear();
+
+            int index = -1;
+
+            if (EnsureConnected())
+            {
+                UpdatePassphraseIfNeeded();
+
+                _scan.Reset();
+
+                SendAsync(_protocol.Encode(PacketId.Scan, scanFilter));
+
+                index = WaitHandle.WaitAny(new WaitHandle[] { _scan, _error }, ScanTimeout);
+            }
+
+            if (index != 0)
+            {
+                // An error occurred or timeout. Write 0 games.
+                return Array.Empty<NetworkInfo>();
+            }
+
+            return _availableGames.ToArray();
+        }
+
+        private NetworkError ConnectCommon()
+        {
+            bool signalled = _apConnected.WaitOne(FailureTimeout);
+
+            NetworkError error = ConsumeNetworkError();
+
+            if (error != NetworkError.None)
+            {
+                return error;
+            }
+
+            if (signalled && _connectedProxy != null)
+            {
+                _connectedProxy.EnsureProxyReady();
+
+                Config = _connectedProxy.ProxyConfig;
+            }
+
+            return signalled ? NetworkError.None : NetworkError.ConnectTimeout;
+        }
+
+        public NetworkError Connect(ConnectRequest request)
+        {
+            _timeout.DisableTimeout();
+
+            if (!EnsureConnected())
+            {
+                return NetworkError.Unknown;
+            }
+
+            SendAsync(_protocol.Encode(PacketId.Connect, request));
+
+            var networkChangeEvent = new NetworkChangeEventArgs(new NetworkInfo()
+            {
+                Common = request.NetworkInfo.Common,
+                Ldn = request.NetworkInfo.Ldn
+            }, true);
+
+            NetworkChange?.Invoke(this, networkChangeEvent);
+
+            return ConnectCommon();
+        }
+
+        public NetworkError ConnectPrivate(ConnectPrivateRequest request)
+        {
+            _timeout.DisableTimeout();
+
+            if (!EnsureConnected())
+            {
+                return NetworkError.Unknown;
+            }
+
+            SendAsync(_protocol.Encode(PacketId.ConnectPrivate, request));
+
+            return ConnectCommon();
+        }
+
+        private void HandleProxyConfig(LdnHeader header, ProxyConfig config)
+        {
+            Config = config;
+
+            SocketHelpers.RegisterProxy(new LdnProxy(config, this, _protocol));
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/NetworkTimeout.cs

@@ -0,0 +1,83 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu
+{
+    class NetworkTimeout : IDisposable
+    {
+        private readonly int _idleTimeout;
+        private readonly Action _timeoutCallback;
+        private CancellationTokenSource _cancel;
+
+        private readonly object _lock = new object();
+
+        public NetworkTimeout(int idleTimeout, Action timeoutCallback)
+        {
+            _idleTimeout = idleTimeout;
+            _timeoutCallback = timeoutCallback;
+        }
+
+        private async Task TimeoutTask()
+        {
+            CancellationTokenSource cts;
+
+            lock (_lock)
+            {
+                cts = _cancel;
+            }
+
+            if (cts == null)
+            {
+                return;
+            }
+
+            try
+            {
+                await Task.Delay(_idleTimeout, cts.Token);
+            }
+            catch (TaskCanceledException)
+            {
+                return; // Timeout cancelled.
+            }
+
+            lock (_lock)
+            {
+                // Run the timeout callback. If the cancel token source has been replaced, we have _just_ been cancelled.
+                if (cts == _cancel)
+                {
+                    _timeoutCallback();
+                }
+            }
+        }
+
+        public bool RefreshTimeout()
+        {
+            lock (_lock)
+            {
+                _cancel?.Cancel();
+
+                _cancel = new CancellationTokenSource();
+
+                Task.Run(TimeoutTask);
+            }
+
+            return true;
+        }
+
+        public void DisableTimeout()
+        {
+            lock (_lock)
+            {
+                _cancel?.Cancel();
+
+                _cancel = new CancellationTokenSource();
+            }
+        }
+
+        public void Dispose()
+        {
+            DisableTimeout();
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/EphemeralPortPool.cs

@@ -0,0 +1,53 @@
+using System.Collections.Generic;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy
+{
+    public class EphemeralPortPool
+    {
+        private const ushort EphemeralBase = 49152;
+
+        private readonly List<ushort> _ephemeralPorts = new List<ushort>();
+
+        private readonly object _lock = new object();
+
+        public ushort Get()
+        {
+            ushort port = EphemeralBase;
+            lock (_lock)
+            {
+                // Starting at the ephemeral port base, return an ephemeral port that is not in use.
+                // Returns 0 if the range is exhausted.
+
+                for (int i = 0; i < _ephemeralPorts.Count; i++)
+                {
+                    ushort existingPort = _ephemeralPorts[i];
+
+                    if (existingPort > port)
+                    {
+                        // The port was free - take it.
+                        _ephemeralPorts.Insert(i, port);
+
+                        return port;
+                    }
+
+                    port++;
+                }
+
+                if (port != 0)
+                {
+                    _ephemeralPorts.Add(port);
+                }
+
+                return port;
+            }
+        }
+
+        public void Return(ushort port)
+        {
+            lock (_lock)
+            {
+                _ephemeralPorts.Remove(port);
+            }
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/LdnProxy.cs

@@ -0,0 +1,254 @@
+using Ryujinx.Common.Logging;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy
+{
+    class LdnProxy : IDisposable
+    {
+        public EndPoint LocalEndpoint { get; }
+        public IPAddress LocalAddress { get; }
+
+        private readonly List<LdnProxySocket> _sockets = new List<LdnProxySocket>();
+        private readonly Dictionary<ProtocolType, EphemeralPortPool> _ephemeralPorts = new Dictionary<ProtocolType, EphemeralPortPool>();
+
+        private readonly IProxyClient _parent;
+        private RyuLdnProtocol _protocol;
+        private readonly uint _subnetMask;
+        private readonly uint _localIp;
+        private readonly uint _broadcast;
+
+        public LdnProxy(ProxyConfig config, IProxyClient client, RyuLdnProtocol protocol)
+        {
+            _parent = client;
+            _protocol = protocol;
+
+            _ephemeralPorts[ProtocolType.Udp] = new EphemeralPortPool();
+            _ephemeralPorts[ProtocolType.Tcp] = new EphemeralPortPool();
+
+            byte[] address = BitConverter.GetBytes(config.ProxyIp);
+            Array.Reverse(address);
+            LocalAddress = new IPAddress(address);
+
+            _subnetMask = config.ProxySubnetMask;
+            _localIp = config.ProxyIp;
+            _broadcast = _localIp | (~_subnetMask);
+
+            RegisterHandlers(protocol);
+        }
+
+        public bool Supported(AddressFamily domain, SocketType type, ProtocolType protocol)
+        {
+            if (protocol == ProtocolType.Tcp)
+            {
+                Logger.Error?.PrintMsg(LogClass.ServiceLdn, "Tcp proxy networking is untested. Please report this game so that it can be tested.");
+            }
+            return domain == AddressFamily.InterNetwork && (protocol == ProtocolType.Tcp || protocol == ProtocolType.Udp);
+        }
+
+        private void RegisterHandlers(RyuLdnProtocol protocol)
+        {
+            protocol.ProxyConnect += HandleConnectionRequest;
+            protocol.ProxyConnectReply += HandleConnectionResponse;
+            protocol.ProxyData += HandleData;
+            protocol.ProxyDisconnect += HandleDisconnect;
+
+            _protocol = protocol;
+        }
+
+        public void UnregisterHandlers(RyuLdnProtocol protocol)
+        {
+            protocol.ProxyConnect -= HandleConnectionRequest;
+            protocol.ProxyConnectReply -= HandleConnectionResponse;
+            protocol.ProxyData -= HandleData;
+            protocol.ProxyDisconnect -= HandleDisconnect;
+        }
+
+        public ushort GetEphemeralPort(ProtocolType type)
+        {
+            return _ephemeralPorts[type].Get();
+        }
+
+        public void ReturnEphemeralPort(ProtocolType type, ushort port)
+        {
+            _ephemeralPorts[type].Return(port);
+        }
+
+        public void RegisterSocket(LdnProxySocket socket)
+        {
+            lock (_sockets)
+            {
+                _sockets.Add(socket);
+            }
+        }
+
+        public void UnregisterSocket(LdnProxySocket socket)
+        {
+            lock (_sockets)
+            {
+                _sockets.Remove(socket);
+            }
+        }
+
+        private void ForRoutedSockets(ProxyInfo info, Action<LdnProxySocket> action)
+        {
+            lock (_sockets)
+            {
+                foreach (LdnProxySocket socket in _sockets)
+                {
+                    // Must match protocol and destination port.
+                    if (socket.ProtocolType != info.Protocol || socket.LocalEndPoint is not IPEndPoint endpoint || endpoint.Port != info.DestPort)
+                    {
+                        continue;
+                    }
+
+                    // We can assume packets routed to us have been sent to our destination.
+                    // They will either be sent to us, or broadcast packets.
+
+                    action(socket);
+                }
+            }
+        }
+
+        public void HandleConnectionRequest(LdnHeader header, ProxyConnectRequest request)
+        {
+            ForRoutedSockets(request.Info, (socket) =>
+            {
+                socket.HandleConnectRequest(request);
+            });
+        }
+
+        public void HandleConnectionResponse(LdnHeader header, ProxyConnectResponse response)
+        {
+            ForRoutedSockets(response.Info, (socket) =>
+            {
+                socket.HandleConnectResponse(response);
+            });
+        }
+
+        public void HandleData(LdnHeader header, ProxyDataHeader proxyHeader, byte[] data)
+        {
+            ProxyDataPacket packet = new ProxyDataPacket() { Header = proxyHeader, Data = data };
+
+            ForRoutedSockets(proxyHeader.Info, (socket) =>
+            {
+                socket.IncomingData(packet);
+            });
+        }
+
+        public void HandleDisconnect(LdnHeader header, ProxyDisconnectMessage disconnect)
+        {
+            ForRoutedSockets(disconnect.Info, (socket) =>
+            {
+                socket.HandleDisconnect(disconnect);
+            });
+        }
+
+        private uint GetIpV4(IPEndPoint endpoint)
+        {
+            if (endpoint.AddressFamily != AddressFamily.InterNetwork)
+            {
+                throw new NotSupportedException();
+            }
+
+            byte[] address = endpoint.Address.GetAddressBytes();
+            Array.Reverse(address);
+
+            return BitConverter.ToUInt32(address);
+        }
+
+        private ProxyInfo MakeInfo(IPEndPoint localEp, IPEndPoint remoteEP, ProtocolType type)
+        {
+            return new ProxyInfo
+            {
+                SourceIpV4 = GetIpV4(localEp),
+                SourcePort = (ushort)localEp.Port,
+
+                DestIpV4 = GetIpV4(remoteEP),
+                DestPort = (ushort)remoteEP.Port,
+
+                Protocol = type
+            };
+        }
+
+        public void RequestConnection(IPEndPoint localEp, IPEndPoint remoteEp, ProtocolType type)
+        {
+            // We must ask the other side to initialize a connection, so they can accept a socket for us.
+
+            ProxyConnectRequest request = new ProxyConnectRequest
+            {
+                Info = MakeInfo(localEp, remoteEp, type)
+            };
+
+            _parent.SendAsync(_protocol.Encode(PacketId.ProxyConnect, request));
+        }
+
+        public void SignalConnected(IPEndPoint localEp, IPEndPoint remoteEp, ProtocolType type)
+        {
+            // We must tell the other side that we have accepted their request for connection.
+
+            ProxyConnectResponse request = new ProxyConnectResponse
+            {
+                Info = MakeInfo(localEp, remoteEp, type)
+            };
+
+            _parent.SendAsync(_protocol.Encode(PacketId.ProxyConnectReply, request));
+        }
+
+        public void EndConnection(IPEndPoint localEp, IPEndPoint remoteEp, ProtocolType type)
+        {
+            // We must tell the other side that our connection is dropped.
+
+            ProxyDisconnectMessage request = new ProxyDisconnectMessage
+            {
+                Info = MakeInfo(localEp, remoteEp, type),
+                DisconnectReason = 0 // TODO
+            };
+
+            _parent.SendAsync(_protocol.Encode(PacketId.ProxyDisconnect, request));
+        }
+
+        public int SendTo(ReadOnlySpan<byte> buffer, SocketFlags flags, IPEndPoint localEp, IPEndPoint remoteEp, ProtocolType type)
+        {
+            // We send exactly as much as the user wants us to, currently instantly.
+            // TODO: handle over "virtual mtu" (we have a max packet size to worry about anyways). fragment if tcp? throw if udp?
+
+            ProxyDataHeader request = new ProxyDataHeader
+            {
+                Info = MakeInfo(localEp, remoteEp, type),
+                DataLength = (uint)buffer.Length
+            };
+
+            _parent.SendAsync(_protocol.Encode(PacketId.ProxyData, request, buffer.ToArray()));
+
+            return buffer.Length;
+        }
+
+        public bool IsBroadcast(uint ip)
+        {
+            return ip == _broadcast;
+        }
+
+        public bool IsMyself(uint ip)
+        {
+            return ip == _localIp;
+        }
+
+        public void Dispose()
+        {
+            UnregisterHandlers(_protocol);
+
+            lock (_sockets)
+            {
+                foreach (LdnProxySocket socket in _sockets)
+                {
+                    socket.ProxyDestroyed();
+                }
+            }
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/LdnProxySocket.cs

@@ -0,0 +1,797 @@
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
+using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl;
+using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy
+{
+    /// <summary>
+    /// This socket is forwarded through a TCP stream that goes through the Ldn server.
+    /// The Ldn server will then route the packets we send (or need to receive) within the virtual adhoc network.
+    /// </summary>
+    class LdnProxySocket : ISocketImpl
+    {
+        private readonly LdnProxy _proxy;
+
+        private bool _isListening;
+        private readonly List<LdnProxySocket> _listenSockets = new List<LdnProxySocket>();
+
+        private readonly Queue<ProxyConnectRequest> _connectRequests = new Queue<ProxyConnectRequest>();
+
+        private readonly AutoResetEvent _acceptEvent = new AutoResetEvent(false);
+        private readonly int _acceptTimeout = -1;
+
+        private readonly Queue<int> _errors = new Queue<int>();
+
+        private readonly AutoResetEvent _connectEvent = new AutoResetEvent(false);
+        private ProxyConnectResponse _connectResponse;
+
+        private int _receiveTimeout = -1;
+        private readonly AutoResetEvent _receiveEvent = new AutoResetEvent(false);
+        private readonly Queue<ProxyDataPacket> _receiveQueue = new Queue<ProxyDataPacket>();
+
+        // private int _sendTimeout = -1; // Sends are techically instant right now, so not _really_ used.
+
+        private bool _connecting;
+        private bool _broadcast;
+        private bool _readShutdown;
+        // private bool _writeShutdown;
+        private bool _closed;
+
+        private readonly Dictionary<SocketOptionName, int> _socketOptions = new Dictionary<SocketOptionName, int>()
+        {
+            { SocketOptionName.Broadcast,       0 }, //TODO: honor this value
+            { SocketOptionName.DontLinger,      0 },
+            { SocketOptionName.Debug,           0 },
+            { SocketOptionName.Error,           0 },
+            { SocketOptionName.KeepAlive,       0 },
+            { SocketOptionName.OutOfBandInline, 0 },
+            { SocketOptionName.ReceiveBuffer,   131072 },
+            { SocketOptionName.ReceiveTimeout,  -1 },
+            { SocketOptionName.SendBuffer,      131072 },
+            { SocketOptionName.SendTimeout,     -1 },
+            { SocketOptionName.Type,            0 },
+            { SocketOptionName.ReuseAddress,    0 } //TODO: honor this value
+        };
+
+        public EndPoint RemoteEndPoint { get; private set; }
+
+        public EndPoint LocalEndPoint { get; private set; }
+
+        public bool Connected { get; private set; }
+
+        public bool IsBound { get; private set; }
+
+        public AddressFamily AddressFamily { get; }
+
+        public SocketType SocketType { get; }
+
+        public ProtocolType ProtocolType { get; }
+
+        public bool Blocking { get; set; }
+
+        public int Available
+        {
+            get
+            {
+                int result = 0;
+
+                lock (_receiveQueue)
+                {
+                    foreach (ProxyDataPacket data in _receiveQueue)
+                    {
+                        result += data.Data.Length;
+                    }
+                }
+
+                return result;
+            }
+        }
+
+        public bool Readable
+        {
+            get
+            {
+                if (_isListening)
+                {
+                    lock (_connectRequests)
+                    {
+                        return _connectRequests.Count > 0;
+                    }
+                }
+                else
+                {
+                    if (_readShutdown)
+                    {
+                        return true;
+                    }
+
+                    lock (_receiveQueue)
+                    {
+                        return _receiveQueue.Count > 0;
+                    }
+                }
+
+            }
+        }
+        public bool Writable => Connected || ProtocolType == ProtocolType.Udp;
+        public bool Error => false;
+
+        public LdnProxySocket(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType, LdnProxy proxy)
+        {
+            AddressFamily = addressFamily;
+            SocketType = socketType;
+            ProtocolType = protocolType;
+
+            _proxy = proxy;
+            _socketOptions[SocketOptionName.Type] = (int)socketType;
+
+            proxy.RegisterSocket(this);
+        }
+
+        private IPEndPoint EnsureLocalEndpoint(bool replace)
+        {
+            if (LocalEndPoint != null)
+            {
+                if (replace)
+                {
+                    _proxy.ReturnEphemeralPort(ProtocolType, (ushort)((IPEndPoint)LocalEndPoint).Port);
+                }
+                else
+                {
+                    return (IPEndPoint)LocalEndPoint;
+                }
+            }
+
+            IPEndPoint localEp = new IPEndPoint(_proxy.LocalAddress, _proxy.GetEphemeralPort(ProtocolType));
+            LocalEndPoint = localEp;
+
+            return localEp;
+        }
+
+        public LdnProxySocket AsAccepted(IPEndPoint remoteEp)
+        {
+            Connected = true;
+            RemoteEndPoint = remoteEp;
+
+            IPEndPoint localEp = EnsureLocalEndpoint(true);
+
+            _proxy.SignalConnected(localEp, remoteEp, ProtocolType);
+
+            return this;
+        }
+
+        private void SignalError(WsaError error)
+        {
+            lock (_errors)
+            {
+                _errors.Enqueue((int)error);
+            }
+        }
+
+        private IPEndPoint GetEndpoint(uint ipv4, ushort port)
+        {
+            byte[] address = BitConverter.GetBytes(ipv4);
+            Array.Reverse(address);
+
+            return new IPEndPoint(new IPAddress(address), port);
+        }
+
+        public void IncomingData(ProxyDataPacket packet)
+        {
+            bool isBroadcast = _proxy.IsBroadcast(packet.Header.Info.DestIpV4);
+
+            if (!_closed && (_broadcast || !isBroadcast))
+            {
+                lock (_receiveQueue)
+                {
+                    _receiveQueue.Enqueue(packet);
+                }
+            }
+        }
+
+        public ISocketImpl Accept()
+        {
+            if (!_isListening)
+            {
+                throw new InvalidOperationException();
+            }
+
+            // Accept a pending request to this socket.
+
+            lock (_connectRequests)
+            {
+                if (!Blocking && _connectRequests.Count == 0)
+                {
+                    throw new SocketException((int)WsaError.WSAEWOULDBLOCK);
+                }
+            }
+
+            while (true)
+            {
+                _acceptEvent.WaitOne(_acceptTimeout);
+
+                lock (_connectRequests)
+                {
+                    while (_connectRequests.Count > 0)
+                    {
+                        ProxyConnectRequest request = _connectRequests.Dequeue();
+
+                        if (_connectRequests.Count > 0)
+                        {
+                            _acceptEvent.Set(); // Still more accepts to do.
+                        }
+
+                        // Is this request made for us?
+                        IPEndPoint endpoint = GetEndpoint(request.Info.DestIpV4, request.Info.DestPort);
+
+                        if (Equals(endpoint, LocalEndPoint))
+                        {
+                            // Yes - let's accept.
+                            IPEndPoint remoteEndpoint = GetEndpoint(request.Info.SourceIpV4, request.Info.SourcePort);
+
+                            LdnProxySocket socket = new LdnProxySocket(AddressFamily, SocketType, ProtocolType, _proxy).AsAccepted(remoteEndpoint);
+
+                            lock (_listenSockets)
+                            {
+                                _listenSockets.Add(socket);
+                            }
+
+                            return socket;
+                        }
+                    }
+                }
+            }
+        }
+
+        public void Bind(EndPoint localEP)
+        {
+            ArgumentNullException.ThrowIfNull(localEP);
+
+            if (LocalEndPoint != null)
+            {
+                _proxy.ReturnEphemeralPort(ProtocolType, (ushort)((IPEndPoint)LocalEndPoint).Port);
+            }
+            var asIPEndpoint = (IPEndPoint)localEP;
+            if (asIPEndpoint.Port == 0)
+            {
+                asIPEndpoint.Port = (ushort)_proxy.GetEphemeralPort(ProtocolType);
+            }
+
+            LocalEndPoint = (IPEndPoint)localEP;
+
+            IsBound = true;
+        }
+
+        public void Close()
+        {
+            _closed = true;
+
+            _proxy.UnregisterSocket(this);
+
+            if (Connected)
+            {
+                Disconnect(false);
+            }
+
+            lock (_listenSockets)
+            {
+                foreach (LdnProxySocket socket in _listenSockets)
+                {
+                    socket.Close();
+                }
+            }
+
+            _isListening = false;
+        }
+
+        public void Connect(EndPoint remoteEP)
+        {
+            if (_isListening || !IsBound)
+            {
+                throw new InvalidOperationException();
+            }
+
+            if (remoteEP is not IPEndPoint)
+            {
+                throw new NotSupportedException();
+            }
+
+            IPEndPoint localEp = EnsureLocalEndpoint(true);
+
+            _connecting = true;
+
+            _proxy.RequestConnection(localEp, (IPEndPoint)remoteEP, ProtocolType);
+
+            if (!Blocking && ProtocolType == ProtocolType.Tcp)
+            {
+                throw new SocketException((int)WsaError.WSAEWOULDBLOCK);
+            }
+
+            _connectEvent.WaitOne(); //timeout?
+
+            if (_connectResponse.Info.SourceIpV4 == 0)
+            {
+                throw new SocketException((int)WsaError.WSAECONNREFUSED);
+            }
+
+            _connectResponse = default;
+        }
+
+        public void HandleConnectResponse(ProxyConnectResponse obj)
+        {
+            if (!_connecting)
+            {
+                return;
+            }
+
+            _connecting = false;
+
+            if (_connectResponse.Info.SourceIpV4 != 0)
+            {
+                IPEndPoint remoteEp = GetEndpoint(obj.Info.SourceIpV4, obj.Info.SourcePort);
+                RemoteEndPoint = remoteEp;
+
+                Connected = true;
+            }
+            else
+            {
+                // Connection failed
+
+                SignalError(WsaError.WSAECONNREFUSED);
+            }
+        }
+
+        public void Disconnect(bool reuseSocket)
+        {
+            if (Connected)
+            {
+                ConnectionEnded();
+
+                // The other side needs to be notified that connection ended.
+                _proxy.EndConnection(LocalEndPoint as IPEndPoint, RemoteEndPoint as IPEndPoint, ProtocolType);
+            }
+        }
+
+        private void ConnectionEnded()
+        {
+            if (Connected)
+            {
+                RemoteEndPoint = null;
+                Connected = false;
+            }
+        }
+
+        public void GetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, byte[] optionValue)
+        {
+            if (optionLevel != SocketOptionLevel.Socket)
+            {
+                throw new NotImplementedException();
+            }
+
+            if (_socketOptions.TryGetValue(optionName, out int result))
+            {
+                byte[] data = BitConverter.GetBytes(result);
+                Array.Copy(data, 0, optionValue, 0, Math.Min(data.Length, optionValue.Length));
+            }
+            else
+            {
+                throw new NotImplementedException();
+            }
+        }
+
+        public void Listen(int backlog)
+        {
+            if (!IsBound)
+            {
+                throw new SocketException();
+            }
+
+            _isListening = true;
+        }
+
+        public void HandleConnectRequest(ProxyConnectRequest obj)
+        {
+            lock (_connectRequests)
+            {
+                _connectRequests.Enqueue(obj);
+            }
+
+            _connectEvent.Set();
+        }
+
+        public void HandleDisconnect(ProxyDisconnectMessage message)
+        {
+            Disconnect(false);
+        }
+
+        public int Receive(Span<byte> buffer)
+        {
+            EndPoint dummy = new IPEndPoint(IPAddress.Any, 0);
+
+            return ReceiveFrom(buffer, SocketFlags.None, ref dummy);
+        }
+
+        public int Receive(Span<byte> buffer, SocketFlags flags)
+        {
+            EndPoint dummy = new IPEndPoint(IPAddress.Any, 0);
+
+            return ReceiveFrom(buffer, flags, ref dummy);
+        }
+
+        public int Receive(Span<byte> buffer, SocketFlags flags, out SocketError socketError)
+        {
+            EndPoint dummy = new IPEndPoint(IPAddress.Any, 0);
+
+            return ReceiveFrom(buffer, flags, out socketError, ref dummy);
+        }
+
+        public int ReceiveFrom(Span<byte> buffer, SocketFlags flags, ref EndPoint remoteEp)
+        {
+            // We just receive all packets meant for us anyways regardless of EP in the actual implementation.
+            // The point is mostly to return the endpoint that we got the data from.
+
+            if (!Connected && ProtocolType == ProtocolType.Tcp)
+            {
+                throw new SocketException((int)WsaError.WSAECONNRESET);
+            }
+
+            lock (_receiveQueue)
+            {
+                if (_receiveQueue.Count > 0)
+                {
+                    return ReceiveFromQueue(buffer, flags, ref remoteEp);
+                }
+                else if (_readShutdown)
+                {
+                    return 0;
+                }
+                else if (!Blocking)
+                {
+                    throw new SocketException((int)WsaError.WSAEWOULDBLOCK);
+                }
+            }
+
+            int timeout = _receiveTimeout;
+
+            _receiveEvent.WaitOne(timeout == 0 ? -1 : timeout);
+
+            if (!Connected && ProtocolType == ProtocolType.Tcp)
+            {
+                throw new SocketException((int)WsaError.WSAECONNRESET);
+            }
+
+            lock (_receiveQueue)
+            {
+                if (_receiveQueue.Count > 0)
+                {
+                    return ReceiveFromQueue(buffer, flags, ref remoteEp);
+                }
+                else if (_readShutdown)
+                {
+                    return 0;
+                }
+                else
+                {
+                    throw new SocketException((int)WsaError.WSAETIMEDOUT);
+                }
+            }
+        }
+
+        public int ReceiveFrom(Span<byte> buffer, SocketFlags flags, out SocketError socketError, ref EndPoint remoteEp)
+        {
+            // We just receive all packets meant for us anyways regardless of EP in the actual implementation.
+            // The point is mostly to return the endpoint that we got the data from.
+
+            if (!Connected && ProtocolType == ProtocolType.Tcp)
+            {
+                socketError = SocketError.ConnectionReset;
+                return -1;
+            }
+
+            lock (_receiveQueue)
+            {
+                if (_receiveQueue.Count > 0)
+                {
+                    return ReceiveFromQueue(buffer, flags, out socketError, ref remoteEp);
+                }
+                else if (_readShutdown)
+                {
+                    socketError = SocketError.Success;
+                    return 0;
+                }
+                else if (!Blocking)
+                {
+                    throw new SocketException((int)WsaError.WSAEWOULDBLOCK);
+                }
+            }
+
+            int timeout = _receiveTimeout;
+
+            _receiveEvent.WaitOne(timeout == 0 ? -1 : timeout);
+
+            if (!Connected && ProtocolType == ProtocolType.Tcp)
+            {
+                throw new SocketException((int)WsaError.WSAECONNRESET);
+            }
+
+            lock (_receiveQueue)
+            {
+                if (_receiveQueue.Count > 0)
+                {
+                    return ReceiveFromQueue(buffer, flags, out socketError, ref remoteEp);
+                }
+                else if (_readShutdown)
+                {
+                    socketError = SocketError.Success;
+                    return 0;
+                }
+                else
+                {
+                    socketError = SocketError.TimedOut;
+                    return -1;
+                }
+            }
+        }
+
+        private int ReceiveFromQueue(Span<byte> buffer, SocketFlags flags, ref EndPoint remoteEp)
+        {
+            int size = buffer.Length;
+
+            // Assumes we have the receive queue lock, and at least one item in the queue.
+            ProxyDataPacket packet = _receiveQueue.Peek();
+
+            remoteEp = GetEndpoint(packet.Header.Info.SourceIpV4, packet.Header.Info.SourcePort);
+
+            bool peek = (flags & SocketFlags.Peek) != 0;
+
+            int read;
+
+            if (packet.Data.Length > size)
+            {
+                read = size;
+
+                // Cannot fit in the output buffer. Copy up to what we've got.
+                packet.Data.AsSpan(0, size).CopyTo(buffer);
+
+                if (ProtocolType == ProtocolType.Udp)
+                {
+                    // Udp overflows, loses the data, then throws an exception.
+
+                    if (!peek)
+                    {
+                        _receiveQueue.Dequeue();
+                    }
+
+                    throw new SocketException((int)WsaError.WSAEMSGSIZE);
+                }
+                else if (ProtocolType == ProtocolType.Tcp)
+                {
+                    // Split the data at the buffer boundary. It will stay on the recieve queue.
+
+                    byte[] newData = new byte[packet.Data.Length - size];
+                    Array.Copy(packet.Data, size, newData, 0, newData.Length);
+
+                    packet.Data = newData;
+                }
+            }
+            else
+            {
+                read = packet.Data.Length;
+
+                packet.Data.AsSpan(0, packet.Data.Length).CopyTo(buffer);
+
+                if (!peek)
+                {
+                    _receiveQueue.Dequeue();
+                }
+            }
+
+            return read;
+        }
+
+        private int ReceiveFromQueue(Span<byte> buffer, SocketFlags flags, out SocketError socketError, ref EndPoint remoteEp)
+        {
+            int size = buffer.Length;
+
+            // Assumes we have the receive queue lock, and at least one item in the queue.
+            ProxyDataPacket packet = _receiveQueue.Peek();
+
+            remoteEp = GetEndpoint(packet.Header.Info.SourceIpV4, packet.Header.Info.SourcePort);
+
+            bool peek = (flags & SocketFlags.Peek) != 0;
+
+            int read;
+
+            if (packet.Data.Length > size)
+            {
+                read = size;
+
+                // Cannot fit in the output buffer. Copy up to what we've got.
+                packet.Data.AsSpan(0, size).CopyTo(buffer);
+
+                if (ProtocolType == ProtocolType.Udp)
+                {
+                    // Udp overflows, loses the data, then throws an exception.
+
+                    if (!peek)
+                    {
+                        _receiveQueue.Dequeue();
+                    }
+
+                    socketError = SocketError.MessageSize;
+                    return -1;
+                }
+                else if (ProtocolType == ProtocolType.Tcp)
+                {
+                    // Split the data at the buffer boundary. It will stay on the recieve queue.
+
+                    byte[] newData = new byte[packet.Data.Length - size];
+                    Array.Copy(packet.Data, size, newData, 0, newData.Length);
+
+                    packet.Data = newData;
+                }
+            }
+            else
+            {
+                read = packet.Data.Length;
+
+                packet.Data.AsSpan(0, packet.Data.Length).CopyTo(buffer);
+
+                if (!peek)
+                {
+                    _receiveQueue.Dequeue();
+                }
+            }
+
+            socketError = SocketError.Success;
+
+            return read;
+        }
+
+        public int Send(ReadOnlySpan<byte> buffer)
+        {
+            // Send to the remote host chosen when we "connect" or "accept".
+            if (!Connected)
+            {
+                throw new SocketException();
+            }
+
+            return SendTo(buffer, SocketFlags.None, RemoteEndPoint);
+        }
+
+        public int Send(ReadOnlySpan<byte> buffer, SocketFlags flags)
+        {
+            // Send to the remote host chosen when we "connect" or "accept".
+            if (!Connected)
+            {
+                throw new SocketException();
+            }
+
+            return SendTo(buffer, flags, RemoteEndPoint);
+        }
+
+        public int Send(ReadOnlySpan<byte> buffer, SocketFlags flags, out SocketError socketError)
+        {
+            // Send to the remote host chosen when we "connect" or "accept".
+            if (!Connected)
+            {
+                throw new SocketException();
+            }
+
+            return SendTo(buffer, flags, out socketError, RemoteEndPoint);
+        }
+
+        public int SendTo(ReadOnlySpan<byte> buffer, SocketFlags flags, EndPoint remoteEP)
+        {
+            if (!Connected && ProtocolType == ProtocolType.Tcp)
+            {
+                throw new SocketException((int)WsaError.WSAECONNRESET);
+            }
+
+            IPEndPoint localEp = EnsureLocalEndpoint(false);
+
+            if (remoteEP is not IPEndPoint)
+            {
+                throw new NotSupportedException();
+            }
+
+            return _proxy.SendTo(buffer, flags, localEp, (IPEndPoint)remoteEP, ProtocolType);
+        }
+
+        public int SendTo(ReadOnlySpan<byte> buffer, SocketFlags flags, out SocketError socketError, EndPoint remoteEP)
+        {
+            if (!Connected && ProtocolType == ProtocolType.Tcp)
+            {
+                socketError = SocketError.ConnectionReset;
+                return -1;
+            }
+
+            IPEndPoint localEp = EnsureLocalEndpoint(false);
+
+            if (remoteEP is not IPEndPoint)
+            {
+                // throw new NotSupportedException();
+                socketError = SocketError.OperationNotSupported;
+                return -1;
+            }
+
+            socketError = SocketError.Success;
+
+            return _proxy.SendTo(buffer, flags, localEp, (IPEndPoint)remoteEP, ProtocolType);
+        }
+
+        public bool Poll(int microSeconds, SelectMode mode)
+        {
+            return mode switch
+            {
+                SelectMode.SelectRead => Readable,
+                SelectMode.SelectWrite => Writable,
+                SelectMode.SelectError => Error,
+                _ => false
+            };
+        }
+
+        public void SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, int optionValue)
+        {
+            if (optionLevel != SocketOptionLevel.Socket)
+            {
+                throw new NotImplementedException();
+            }
+
+            switch (optionName)
+            {
+                case SocketOptionName.SendTimeout:
+                    //_sendTimeout = optionValue;
+                    break;
+                case SocketOptionName.ReceiveTimeout:
+                    _receiveTimeout = optionValue;
+                    break;
+                case SocketOptionName.Broadcast:
+                    _broadcast = optionValue != 0;
+                    break;
+            }
+
+            lock (_socketOptions)
+            {
+                _socketOptions[optionName] = optionValue;
+            }
+        }
+
+        public void SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, object optionValue)
+        {
+            // Just linger uses this for now in BSD, which we ignore.
+        }
+
+        public void Shutdown(SocketShutdown how)
+        {
+            switch (how)
+            {
+                case SocketShutdown.Both:
+                    _readShutdown = true;
+                    // _writeShutdown = true;
+                    break;
+                case SocketShutdown.Receive:
+                    _readShutdown = true;
+                    break;
+                case SocketShutdown.Send:
+                    // _writeShutdown = true;
+                    break;
+            }
+        }
+
+        public void ProxyDestroyed()
+        {
+            // Do nothing, for now. Will likely be more useful with TCP.
+        }
+
+        public void Dispose()
+        {
+
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/P2pProxyClient.cs

@@ -0,0 +1,93 @@
+using Ryujinx.Common.Logging;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types;
+using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy;
+using System.Net.Sockets;
+using System.Threading;
+using TcpClient = NetCoreServer.TcpClient;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy
+{
+    class P2pProxyClient : TcpClient, IProxyClient
+    {
+        private const int FailureTimeout = 4000;
+
+        public ProxyConfig ProxyConfig { get; private set; }
+
+        private readonly RyuLdnProtocol _protocol;
+
+        private readonly ManualResetEvent _connected = new ManualResetEvent(false);
+        private readonly ManualResetEvent _ready = new ManualResetEvent(false);
+        private readonly AutoResetEvent _error = new AutoResetEvent(false);
+
+        public P2pProxyClient(string address, int port) : base(address, port)
+        {
+            if (ProxyHelpers.SupportsNoDelay())
+            {
+                OptionNoDelay = true;
+            }
+
+            _protocol = new RyuLdnProtocol();
+
+            _protocol.ProxyConfig += HandleProxyConfig;
+
+            ConnectAsync();
+        }
+
+        protected override void OnConnected()
+        {
+            Logger.Info?.PrintMsg(LogClass.ServiceLdn, $"Proxy TCP client connected a new session with Id {Id}");
+
+            _connected.Set();
+        }
+
+        protected override void OnDisconnected()
+        {
+            Logger.Info?.PrintMsg(LogClass.ServiceLdn, $"Proxy TCP client disconnected a session with Id {Id}");
+
+            SocketHelpers.UnregisterProxy();
+
+            _connected.Reset();
+        }
+
+        protected override void OnReceived(byte[] buffer, long offset, long size)
+        {
+            _protocol.Read(buffer, (int)offset, (int)size);
+        }
+
+        protected override void OnError(SocketError error)
+        {
+            Logger.Info?.PrintMsg(LogClass.ServiceLdn, $"Proxy TCP client caught an error with code {error}");
+
+            _error.Set();
+        }
+
+        private void HandleProxyConfig(LdnHeader header, ProxyConfig config)
+        {
+            ProxyConfig = config;
+
+            SocketHelpers.RegisterProxy(new LdnProxy(config, this, _protocol));
+
+            _ready.Set();
+        }
+
+        public bool EnsureProxyReady()
+        {
+            return _ready.WaitOne(FailureTimeout);
+        }
+
+        public bool PerformAuth(ExternalProxyConfig config)
+        {
+            bool signalled = _connected.WaitOne(FailureTimeout);
+
+            if (!signalled)
+            {
+                return false;
+            }
+
+            SendAsync(_protocol.Encode(PacketId.ExternalProxy, config));
+
+            return true;
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/P2pProxyServer.cs

@@ -0,0 +1,388 @@
+using NetCoreServer;
+using Open.Nat;
+using Ryujinx.Common.Logging;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types;
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy
+{
+    class P2pProxyServer : TcpServer, IDisposable
+    {
+        public const ushort PrivatePortBase = 39990;
+        public const int PrivatePortRange = 10;
+
+        private const ushort PublicPortBase = 39990;
+        private const int PublicPortRange = 10;
+
+        private const ushort PortLeaseLength = 60;
+        private const ushort PortLeaseRenew = 50;
+
+        private const ushort AuthWaitSeconds = 1;
+
+        private readonly ReaderWriterLockSlim _lock = new ReaderWriterLockSlim(LockRecursionPolicy.SupportsRecursion);
+
+        public ushort PrivatePort { get; }
+
+        private ushort _publicPort;
+
+        private bool _disposed;
+        private readonly CancellationTokenSource _disposedCancellation = new CancellationTokenSource();
+
+        private NatDevice _natDevice;
+        private Mapping _portMapping;
+
+        private readonly List<P2pProxySession> _players = new List<P2pProxySession>();
+
+        private readonly List<ExternalProxyToken> _waitingTokens = new List<ExternalProxyToken>();
+        private readonly AutoResetEvent _tokenEvent = new AutoResetEvent(false);
+
+        private uint _broadcastAddress;
+
+        private readonly LdnMasterProxyClient _master;
+        private readonly RyuLdnProtocol _masterProtocol;
+        private readonly RyuLdnProtocol _protocol;
+
+        public P2pProxyServer(LdnMasterProxyClient master, ushort port, RyuLdnProtocol masterProtocol) : base(IPAddress.Any, port)
+        {
+            if (ProxyHelpers.SupportsNoDelay())
+            {
+                OptionNoDelay = true;
+            }
+
+            PrivatePort = port;
+
+            _master = master;
+            _masterProtocol = masterProtocol;
+
+            _masterProtocol.ExternalProxyState += HandleStateChange;
+            _masterProtocol.ExternalProxyToken += HandleToken;
+
+            _protocol = new RyuLdnProtocol();
+        }
+
+        private void HandleToken(LdnHeader header, ExternalProxyToken token)
+        {
+            _lock.EnterWriteLock();
+
+            _waitingTokens.Add(token);
+
+            _lock.ExitWriteLock();
+
+            _tokenEvent.Set();
+        }
+
+        private void HandleStateChange(LdnHeader header, ExternalProxyConnectionState state)
+        {
+            if (!state.Connected)
+            {
+                _lock.EnterWriteLock();
+
+                _waitingTokens.RemoveAll(token => token.VirtualIp == state.IpAddress);
+
+                _players.RemoveAll(player =>
+                {
+                    if (player.VirtualIpAddress == state.IpAddress)
+                    {
+                        player.DisconnectAndStop();
+
+                        return true;
+                    }
+
+                    return false;
+                });
+
+                _lock.ExitWriteLock();
+            }
+        }
+
+        public void Configure(ProxyConfig config)
+        {
+            _broadcastAddress = config.ProxyIp | (~config.ProxySubnetMask);
+        }
+
+        public async Task<ushort> NatPunch()
+        {
+            NatDiscoverer discoverer = new NatDiscoverer();
+            CancellationTokenSource cts = new CancellationTokenSource(1000);
+
+            NatDevice device;
+
+            try
+            {
+                device = await discoverer.DiscoverDeviceAsync(PortMapper.Upnp, cts);
+            }
+            catch (NatDeviceNotFoundException)
+            {
+                return 0;
+            }
+
+            _publicPort = PublicPortBase;
+
+            for (int i = 0; i < PublicPortRange; i++)
+            {
+                try
+                {
+                    _portMapping = new Mapping(Protocol.Tcp, PrivatePort, _publicPort, PortLeaseLength, "Ryujinx Local Multiplayer");
+
+                    await device.CreatePortMapAsync(_portMapping);
+
+                    break;
+                }
+                catch (MappingException)
+                {
+                    _publicPort++;
+                }
+                catch (Exception)
+                {
+                    return 0;
+                }
+
+                if (i == PublicPortRange - 1)
+                {
+                    _publicPort = 0;
+                }
+            }
+
+            if (_publicPort != 0)
+            {
+                _ = Task.Delay(PortLeaseRenew * 1000, _disposedCancellation.Token).ContinueWith((task) => Task.Run(RefreshLease));
+            }
+
+            _natDevice = device;
+
+            return _publicPort;
+        }
+
+        // Proxy handlers
+
+        private void RouteMessage(P2pProxySession sender, ref ProxyInfo info, Action<P2pProxySession> action)
+        {
+            if (info.SourceIpV4 == 0)
+            {
+                // If they sent from a connection bound on 0.0.0.0, make others see it as them.
+                info.SourceIpV4 = sender.VirtualIpAddress;
+            }
+            else if (info.SourceIpV4 != sender.VirtualIpAddress)
+            {
+                // Can't pretend to be somebody else.
+                return;
+            }
+
+            uint destIp = info.DestIpV4;
+
+            if (destIp == 0xc0a800ff)
+            {
+                destIp = _broadcastAddress;
+            }
+
+            bool isBroadcast = destIp == _broadcastAddress;
+
+            _lock.EnterReadLock();
+
+            if (isBroadcast)
+            {
+                _players.ForEach(player =>
+                {
+                    action(player);
+                });
+            }
+            else
+            {
+                P2pProxySession target = _players.FirstOrDefault(player => player.VirtualIpAddress == destIp);
+
+                if (target != null)
+                {
+                    action(target);
+                }
+            }
+
+            _lock.ExitReadLock();
+        }
+
+        public void HandleProxyDisconnect(P2pProxySession sender, LdnHeader header, ProxyDisconnectMessage message)
+        {
+            RouteMessage(sender, ref message.Info, (target) =>
+            {
+                target.SendAsync(sender.Protocol.Encode(PacketId.ProxyDisconnect, message));
+            });
+        }
+
+        public void HandleProxyData(P2pProxySession sender, LdnHeader header, ProxyDataHeader message, byte[] data)
+        {
+            RouteMessage(sender, ref message.Info, (target) =>
+            {
+                target.SendAsync(sender.Protocol.Encode(PacketId.ProxyData, message, data));
+            });
+        }
+
+        public void HandleProxyConnectReply(P2pProxySession sender, LdnHeader header, ProxyConnectResponse message)
+        {
+            RouteMessage(sender, ref message.Info, (target) =>
+            {
+                target.SendAsync(sender.Protocol.Encode(PacketId.ProxyConnectReply, message));
+            });
+        }
+
+        public void HandleProxyConnect(P2pProxySession sender, LdnHeader header, ProxyConnectRequest message)
+        {
+            RouteMessage(sender, ref message.Info, (target) =>
+            {
+                target.SendAsync(sender.Protocol.Encode(PacketId.ProxyConnect, message));
+            });
+        }
+
+        // End proxy handlers
+
+        private async Task RefreshLease()
+        {
+            if (_disposed || _natDevice == null)
+            {
+                return;
+            }
+
+            try
+            {
+                await _natDevice.CreatePortMapAsync(_portMapping);
+            }
+            catch (Exception)
+            {
+
+            }
+
+            _ = Task.Delay(PortLeaseRenew, _disposedCancellation.Token).ContinueWith((task) => Task.Run(RefreshLease));
+        }
+
+        public bool TryRegisterUser(P2pProxySession session, ExternalProxyConfig config)
+        {
+            _lock.EnterWriteLock();
+
+            // Attempt to find matching configuration. If we don't find one, wait for a bit and try again.
+            // Woken by new tokens coming in from the master server.
+
+            IPAddress address = (session.Socket.RemoteEndPoint as IPEndPoint).Address;
+            byte[] addressBytes = ProxyHelpers.AddressTo16Byte(address);
+
+            long time;
+            long endTime = Stopwatch.GetTimestamp() + Stopwatch.Frequency * AuthWaitSeconds;
+
+            do
+            {
+                for (int i = 0; i < _waitingTokens.Count; i++)
+                {
+                    ExternalProxyToken waitToken = _waitingTokens[i];
+
+                    // Allow any client that has a private IP to connect. (indicated by the server as all 0 in the token)
+
+                    bool isPrivate = waitToken.PhysicalIp.AsSpan().SequenceEqual(new byte[16]);
+                    bool ipEqual = isPrivate || waitToken.AddressFamily == address.AddressFamily && waitToken.PhysicalIp.AsSpan().SequenceEqual(addressBytes);
+
+                    if (ipEqual && waitToken.Token.AsSpan().SequenceEqual(config.Token.AsSpan()))
+                    {
+                        // This is a match.
+
+                        _waitingTokens.RemoveAt(i);
+
+                        session.SetIpv4(waitToken.VirtualIp);
+
+                        ProxyConfig pconfig = new ProxyConfig
+                        {
+                            ProxyIp = session.VirtualIpAddress,
+                            ProxySubnetMask = 0xFFFF0000 // TODO: Use from server.
+                        };
+
+                        if (_players.Count == 0)
+                        {
+                            Configure(pconfig);
+                        }
+
+                        _players.Add(session);
+
+                        session.SendAsync(_protocol.Encode(PacketId.ProxyConfig, pconfig));
+
+                        _lock.ExitWriteLock();
+
+                        return true;
+                    }
+                }
+
+                // Couldn't find the token.
+                // It may not have arrived yet, so wait for one to arrive.
+
+                _lock.ExitWriteLock();
+
+                time = Stopwatch.GetTimestamp();
+                int remainingMs = (int)((endTime - time) / (Stopwatch.Frequency / 1000));
+
+                if (remainingMs < 0)
+                {
+                    remainingMs = 0;
+                }
+
+                _tokenEvent.WaitOne(remainingMs);
+
+                _lock.EnterWriteLock();
+
+            } while (time < endTime);
+
+            _lock.ExitWriteLock();
+
+            return false;
+        }
+
+        public void DisconnectProxyClient(P2pProxySession session)
+        {
+            _lock.EnterWriteLock();
+
+            bool removed = _players.Remove(session);
+
+            if (removed)
+            {
+                _master.SendAsync(_masterProtocol.Encode(PacketId.ExternalProxyState, new ExternalProxyConnectionState
+                {
+                    IpAddress = session.VirtualIpAddress,
+                    Connected = false
+                }));
+            }
+
+            _lock.ExitWriteLock();
+        }
+
+        public new void Dispose()
+        {
+            base.Dispose();
+
+            _disposed = true;
+            _disposedCancellation.Cancel();
+
+            try
+            {
+                Task delete = _natDevice?.DeletePortMapAsync(new Mapping(Protocol.Tcp, PrivatePort, _publicPort, 60, "Ryujinx Local Multiplayer"));
+
+                // Just absorb any exceptions.
+                delete?.ContinueWith((task) => { });
+            }
+            catch (Exception)
+            {
+                // Fail silently.
+            }
+        }
+
+        protected override TcpSession CreateSession()
+        {
+            return new P2pProxySession(this);
+        }
+
+        protected override void OnError(SocketError error)
+        {
+            Logger.Info?.PrintMsg(LogClass.ServiceLdn, $"Proxy TCP server caught an error with code {error}");
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/P2pProxySession.cs

@@ -0,0 +1,90 @@
+using NetCoreServer;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
+using System;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy
+{
+    class P2pProxySession : TcpSession
+    {
+        public uint VirtualIpAddress { get; private set; }
+        public RyuLdnProtocol Protocol { get; }
+
+        private readonly P2pProxyServer _parent;
+
+        private bool _masterClosed;
+
+        public P2pProxySession(P2pProxyServer server) : base(server)
+        {
+            _parent = server;
+
+            Protocol = new RyuLdnProtocol();
+
+            Protocol.ProxyDisconnect += HandleProxyDisconnect;
+            Protocol.ProxyData += HandleProxyData;
+            Protocol.ProxyConnectReply += HandleProxyConnectReply;
+            Protocol.ProxyConnect += HandleProxyConnect;
+
+            Protocol.ExternalProxy += HandleAuthentication;
+        }
+
+        private void HandleAuthentication(LdnHeader header, ExternalProxyConfig token)
+        {
+            if (!_parent.TryRegisterUser(this, token))
+            {
+                Disconnect();
+            }
+        }
+
+        public void SetIpv4(uint ip)
+        {
+            VirtualIpAddress = ip;
+        }
+
+        public void DisconnectAndStop()
+        {
+            _masterClosed = true;
+
+            Disconnect();
+        }
+
+        protected override void OnDisconnected()
+        {
+            if (!_masterClosed)
+            {
+                _parent.DisconnectProxyClient(this);
+            }
+        }
+
+        protected override void OnReceived(byte[] buffer, long offset, long size)
+        {
+            try
+            {
+                Protocol.Read(buffer, (int)offset, (int)size);
+            }
+            catch (Exception)
+            {
+                Disconnect();
+            }
+        }
+
+        private void HandleProxyDisconnect(LdnHeader header, ProxyDisconnectMessage message)
+        {
+            _parent.HandleProxyDisconnect(this, header, message);
+        }
+
+        private void HandleProxyData(LdnHeader header, ProxyDataHeader message, byte[] data)
+        {
+            _parent.HandleProxyData(this, header, message, data);
+        }
+
+        private void HandleProxyConnectReply(LdnHeader header, ProxyConnectResponse data)
+        {
+            _parent.HandleProxyConnectReply(this, header, data);
+        }
+
+        private void HandleProxyConnect(LdnHeader header, ProxyConnectRequest message)
+        {
+            _parent.HandleProxyConnect(this, header, message);
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Proxy/ProxyHelpers.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Net;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy
+{
+    static class ProxyHelpers
+    {
+        public static byte[] AddressTo16Byte(IPAddress address)
+        {
+            byte[] ipBytes = new byte[16];
+            byte[] srcBytes = address.GetAddressBytes();
+
+            Array.Copy(srcBytes, 0, ipBytes, 0, srcBytes.Length);
+
+            return ipBytes;
+        }
+
+        public static bool SupportsNoDelay()
+        {
+            return RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/RyuLdnProtocol.cs

@@ -0,0 +1,380 @@
+using Ryujinx.Common.Utilities;
+using Ryujinx.HLE.HOS.Services.Ldn.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types;
+using System;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu
+{
+    class RyuLdnProtocol
+    {
+        private const byte CurrentProtocolVersion = 1;
+        private const int Magic = ('R' << 0) | ('L' << 8) | ('D' << 16) | ('N' << 24);
+        private const int MaxPacketSize = 131072;
+
+        private readonly int _headerSize = Marshal.SizeOf<LdnHeader>();
+
+        private readonly byte[] _buffer = new byte[MaxPacketSize];
+        private int _bufferEnd = 0;
+
+        // Client Packets.
+        public event Action<LdnHeader, InitializeMessage> Initialize;
+        public event Action<LdnHeader, PassphraseMessage> Passphrase;
+        public event Action<LdnHeader, NetworkInfo> Connected;
+        public event Action<LdnHeader, NetworkInfo> SyncNetwork;
+        public event Action<LdnHeader, NetworkInfo> ScanReply;
+        public event Action<LdnHeader> ScanReplyEnd;
+        public event Action<LdnHeader, DisconnectMessage> Disconnected;
+
+        // External Proxy Packets.
+        public event Action<LdnHeader, ExternalProxyConfig> ExternalProxy;
+        public event Action<LdnHeader, ExternalProxyConnectionState> ExternalProxyState;
+        public event Action<LdnHeader, ExternalProxyToken> ExternalProxyToken;
+
+        // Server Packets.
+        public event Action<LdnHeader, CreateAccessPointRequest, byte[]> CreateAccessPoint;
+        public event Action<LdnHeader, CreateAccessPointPrivateRequest, byte[]> CreateAccessPointPrivate;
+        public event Action<LdnHeader, RejectRequest> Reject;
+        public event Action<LdnHeader> RejectReply;
+        public event Action<LdnHeader, SetAcceptPolicyRequest> SetAcceptPolicy;
+        public event Action<LdnHeader, byte[]> SetAdvertiseData;
+        public event Action<LdnHeader, ConnectRequest> Connect;
+        public event Action<LdnHeader, ConnectPrivateRequest> ConnectPrivate;
+        public event Action<LdnHeader, ScanFilter> Scan;
+
+        // Proxy Packets.
+        public event Action<LdnHeader, ProxyConfig> ProxyConfig;
+        public event Action<LdnHeader, ProxyConnectRequest> ProxyConnect;
+        public event Action<LdnHeader, ProxyConnectResponse> ProxyConnectReply;
+        public event Action<LdnHeader, ProxyDataHeader, byte[]> ProxyData;
+        public event Action<LdnHeader, ProxyDisconnectMessage> ProxyDisconnect;
+
+        // Lifecycle Packets.
+        public event Action<LdnHeader, NetworkErrorMessage> NetworkError;
+        public event Action<LdnHeader, PingMessage> Ping;
+
+        public RyuLdnProtocol() { }
+
+        public void Reset()
+        {
+            _bufferEnd = 0;
+        }
+
+        public void Read(byte[] data, int offset, int size)
+        {
+            int index = 0;
+
+            while (index < size)
+            {
+                if (_bufferEnd < _headerSize)
+                {
+                    // Assemble the header first.
+
+                    int copyable = Math.Min(size - index, Math.Min(size, _headerSize - _bufferEnd));
+
+                    Array.Copy(data, index + offset, _buffer, _bufferEnd, copyable);
+
+                    index += copyable;
+                    _bufferEnd += copyable;
+                }
+
+                if (_bufferEnd >= _headerSize)
+                {
+                    // The header is available. Make sure we received all the data (size specified in the header)
+
+                    LdnHeader ldnHeader = MemoryMarshal.Cast<byte, LdnHeader>(_buffer)[0];
+
+                    if (ldnHeader.Magic != Magic)
+                    {
+                        throw new InvalidOperationException("Invalid magic number in received packet.");
+                    }
+
+                    if (ldnHeader.Version != CurrentProtocolVersion)
+                    {
+                        throw new InvalidOperationException($"Protocol version mismatch. Expected ${CurrentProtocolVersion}, was ${ldnHeader.Version}.");
+                    }
+
+                    int finalSize = _headerSize + ldnHeader.DataSize;
+
+                    if (finalSize >= MaxPacketSize)
+                    {
+                        throw new InvalidOperationException($"Max packet size {MaxPacketSize} exceeded.");
+                    }
+
+                    int copyable = Math.Min(size - index, Math.Min(size, finalSize - _bufferEnd));
+
+                    Array.Copy(data, index + offset, _buffer, _bufferEnd, copyable);
+
+                    index += copyable;
+                    _bufferEnd += copyable;
+
+                    if (finalSize == _bufferEnd)
+                    {
+                        // The full packet has been retrieved. Send it to be decoded.
+
+                        byte[] ldnData = new byte[ldnHeader.DataSize];
+
+                        Array.Copy(_buffer, _headerSize, ldnData, 0, ldnData.Length);
+
+                        DecodeAndHandle(ldnHeader, ldnData);
+
+                        Reset();
+                    }
+                }
+            }
+        }
+
+        private (T, byte[]) ParseWithData<T>(byte[] data) where T : struct
+        {
+            T str = default;
+            int size = Marshal.SizeOf(str);
+
+            byte[] remainder = new byte[data.Length - size];
+
+            if (remainder.Length > 0)
+            {
+                Array.Copy(data, size, remainder, 0, remainder.Length);
+            }
+
+            return (MemoryMarshal.Read<T>(data), remainder);
+        }
+
+        private void DecodeAndHandle(LdnHeader header, byte[] data)
+        {
+            switch ((PacketId)header.Type)
+            {
+                // Client Packets.
+                case PacketId.Initialize:
+                    {
+                        Initialize?.Invoke(header, MemoryMarshal.Read<InitializeMessage>(data));
+
+                        break;
+                    }
+                case PacketId.Passphrase:
+                    {
+                        Passphrase?.Invoke(header, MemoryMarshal.Read<PassphraseMessage>(data));
+
+                        break;
+                    }
+                case PacketId.Connected:
+                    {
+                        Connected?.Invoke(header, MemoryMarshal.Read<NetworkInfo>(data));
+
+                        break;
+                    }
+                case PacketId.SyncNetwork:
+                    {
+                        SyncNetwork?.Invoke(header, MemoryMarshal.Read<NetworkInfo>(data));
+
+                        break;
+                    }
+                case PacketId.ScanReply:
+                    {
+                        ScanReply?.Invoke(header, MemoryMarshal.Read<NetworkInfo>(data));
+
+                        break;
+                    }
+
+                case PacketId.ScanReplyEnd:
+                    {
+                        ScanReplyEnd?.Invoke(header);
+
+                        break;
+                    }
+                case PacketId.Disconnect:
+                    {
+                        Disconnected?.Invoke(header, MemoryMarshal.Read<DisconnectMessage>(data));
+
+                        break;
+                    }
+
+                // External Proxy Packets.
+                case PacketId.ExternalProxy:
+                    {
+                        ExternalProxy?.Invoke(header, MemoryMarshal.Read<ExternalProxyConfig>(data));
+
+                        break;
+                    }
+                case PacketId.ExternalProxyState:
+                    {
+                        ExternalProxyState?.Invoke(header, MemoryMarshal.Read<ExternalProxyConnectionState>(data));
+
+                        break;
+                    }
+                case PacketId.ExternalProxyToken:
+                    {
+                        ExternalProxyToken?.Invoke(header, MemoryMarshal.Read<ExternalProxyToken>(data));
+
+                        break;
+                    }
+
+                // Server Packets.
+                case PacketId.CreateAccessPoint:
+                    {
+                        (CreateAccessPointRequest packet, byte[] extraData) = ParseWithData<CreateAccessPointRequest>(data);
+                        CreateAccessPoint?.Invoke(header, packet, extraData);
+                        break;
+                    }
+                case PacketId.CreateAccessPointPrivate:
+                    {
+                        (CreateAccessPointPrivateRequest packet, byte[] extraData) = ParseWithData<CreateAccessPointPrivateRequest>(data);
+                        CreateAccessPointPrivate?.Invoke(header, packet, extraData);
+                        break;
+                    }
+                case PacketId.Reject:
+                    {
+                        Reject?.Invoke(header, MemoryMarshal.Read<RejectRequest>(data));
+
+                        break;
+                    }
+                case PacketId.RejectReply:
+                    {
+                        RejectReply?.Invoke(header);
+
+                        break;
+                    }
+                case PacketId.SetAcceptPolicy:
+                    {
+                        SetAcceptPolicy?.Invoke(header, MemoryMarshal.Read<SetAcceptPolicyRequest>(data));
+
+                        break;
+                    }
+                case PacketId.SetAdvertiseData:
+                    {
+                        SetAdvertiseData?.Invoke(header, data);
+
+                        break;
+                    }
+                case PacketId.Connect:
+                    {
+                        Connect?.Invoke(header, MemoryMarshal.Read<ConnectRequest>(data));
+
+                        break;
+                    }
+                case PacketId.ConnectPrivate:
+                    {
+                        ConnectPrivate?.Invoke(header, MemoryMarshal.Read<ConnectPrivateRequest>(data));
+
+                        break;
+                    }
+                case PacketId.Scan:
+                    {
+                        Scan?.Invoke(header, MemoryMarshal.Read<ScanFilter>(data));
+
+                        break;
+                    }
+
+                // Proxy Packets
+                case PacketId.ProxyConfig:
+                    {
+                        ProxyConfig?.Invoke(header, MemoryMarshal.Read<ProxyConfig>(data));
+
+                        break;
+                    }
+                case PacketId.ProxyConnect:
+                    {
+                        ProxyConnect?.Invoke(header, MemoryMarshal.Read<ProxyConnectRequest>(data));
+
+                        break;
+                    }
+                case PacketId.ProxyConnectReply:
+                    {
+                        ProxyConnectReply?.Invoke(header, MemoryMarshal.Read<ProxyConnectResponse>(data));
+
+                        break;
+                    }
+                case PacketId.ProxyData:
+                    {
+                        (ProxyDataHeader packet, byte[] extraData) = ParseWithData<ProxyDataHeader>(data);
+
+                        ProxyData?.Invoke(header, packet, extraData);
+
+                        break;
+                    }
+                case PacketId.ProxyDisconnect:
+                    {
+                        ProxyDisconnect?.Invoke(header, MemoryMarshal.Read<ProxyDisconnectMessage>(data));
+
+                        break;
+                    }
+
+                // Lifecycle Packets.
+                case PacketId.Ping:
+                    {
+                        Ping?.Invoke(header, MemoryMarshal.Read<PingMessage>(data));
+
+                        break;
+                    }
+                case PacketId.NetworkError:
+                    {
+                        NetworkError?.Invoke(header, MemoryMarshal.Read<NetworkErrorMessage>(data));
+
+                        break;
+                    }
+
+                default:
+                    break;
+            }
+        }
+
+        private static LdnHeader GetHeader(PacketId type, int dataSize)
+        {
+            return new LdnHeader()
+            {
+                Magic = Magic,
+                Version = CurrentProtocolVersion,
+                Type = (byte)type,
+                DataSize = dataSize
+            };
+        }
+
+        public byte[] Encode(PacketId type)
+        {
+            LdnHeader header = GetHeader(type, 0);
+
+            return SpanHelpers.AsSpan<LdnHeader, byte>(ref header).ToArray();
+        }
+
+        public byte[] Encode(PacketId type, byte[] data)
+        {
+            LdnHeader header = GetHeader(type, data.Length);
+
+            byte[] result = SpanHelpers.AsSpan<LdnHeader, byte>(ref header).ToArray();
+
+            Array.Resize(ref result, result.Length + data.Length);
+            Array.Copy(data, 0, result, Marshal.SizeOf<LdnHeader>(), data.Length);
+
+            return result;
+        }
+
+        public byte[] Encode<T>(PacketId type, T packet) where T : unmanaged
+        {
+            byte[] packetData = SpanHelpers.AsSpan<T, byte>(ref packet).ToArray();
+
+            LdnHeader header = GetHeader(type, packetData.Length);
+
+            byte[] result = SpanHelpers.AsSpan<LdnHeader, byte>(ref header).ToArray();
+
+            Array.Resize(ref result, result.Length + packetData.Length);
+            Array.Copy(packetData, 0, result, Marshal.SizeOf<LdnHeader>(), packetData.Length);
+
+            return result;
+        }
+
+        public byte[] Encode<T>(PacketId type, T packet, byte[] data) where T : unmanaged
+        {
+            byte[] packetData = SpanHelpers.AsSpan<T, byte>(ref packet).ToArray();
+
+            LdnHeader header = GetHeader(type, packetData.Length + data.Length);
+
+            byte[] result = SpanHelpers.AsSpan<LdnHeader, byte>(ref header).ToArray();
+
+            Array.Resize(ref result, result.Length + packetData.Length + data.Length);
+            Array.Copy(packetData, 0, result, Marshal.SizeOf<LdnHeader>(), packetData.Length);
+            Array.Copy(data, 0, result, Marshal.SizeOf<LdnHeader>() + packetData.Length, data.Length);
+
+            return result;
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/DisconnectMessage.cs

@@ -0,0 +1,10 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x4)]
+    struct DisconnectMessage
+    {
+        public uint DisconnectIP;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ExternalProxyConfig.cs

@@ -0,0 +1,19 @@
+using Ryujinx.Common.Memory;
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    /// <summary>
+    /// Sent by the server to point a client towards an external server being used as a proxy.
+    /// The client then forwards this to the external proxy after connecting, to verify the connection worked.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Size = 0x26, Pack = 1)]
+    struct ExternalProxyConfig
+    {
+        public Array16<byte> ProxyIp;
+        public AddressFamily AddressFamily;
+        public ushort ProxyPort;
+        public Array16<byte> Token;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ExternalProxyConnectionState.cs

@@ -0,0 +1,18 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    /// <summary>
+    /// Indicates a change in connection state for the given client.
+    /// Is sent to notify the master server when connection is first established.
+    /// Can be sent by the external proxy to the master server to notify it of a proxy disconnect.
+    /// Can be sent by the master server to notify the external proxy of a user leaving a room.
+    /// Both will result in a force kick.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Size = 0x8, Pack = 4)]
+    struct ExternalProxyConnectionState
+    {
+        public uint IpAddress;
+        public bool Connected;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ExternalProxyToken.cs

@@ -0,0 +1,20 @@
+using Ryujinx.Common.Memory;
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    /// <summary>
+    /// Sent by the master server to an external proxy to tell them someone is going to connect.
+    /// This drives authentication, and lets the proxy know what virtual IP to give to each joiner,
+    /// as these are managed by the master server.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Size = 0x28)]
+    struct ExternalProxyToken
+    {
+        public uint VirtualIp;
+        public Array16<byte> Token;
+        public Array16<byte> PhysicalIp;
+        public AddressFamily AddressFamily;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/InitializeMessage.cs

@@ -0,0 +1,20 @@
+using Ryujinx.Common.Memory;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    /// <summary>
+    /// This message is first sent by the client to identify themselves.
+    /// If the server has a token+mac combo that matches the submission, then they are returned their new ID and mac address. (the mac is also reassigned to the new id)
+    /// Otherwise, they are returned a random mac address.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Size = 0x16)]
+    struct InitializeMessage
+    {
+        // All 0 if we don't have an ID yet.
+        public Array16<byte> Id;
+
+        // All 0 if we don't have a mac yet.
+        public Array6<byte> MacAddress;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/LdnHeader.cs

@@ -0,0 +1,13 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0xA)]
+    struct LdnHeader
+    {
+        public uint Magic;
+        public byte Type;
+        public byte Version;
+        public int DataSize;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/PacketId.cs

@@ -0,0 +1,36 @@
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    enum PacketId
+    {
+        Initialize,
+        Passphrase,
+
+        CreateAccessPoint,
+        CreateAccessPointPrivate,
+        ExternalProxy,
+        ExternalProxyToken,
+        ExternalProxyState,
+        SyncNetwork,
+        Reject,
+        RejectReply,
+        Scan,
+        ScanReply,
+        ScanReplyEnd,
+        Connect,
+        ConnectPrivate,
+        Connected,
+        Disconnect,
+
+        ProxyConfig,
+        ProxyConnect,
+        ProxyConnectReply,
+        ProxyData,
+        ProxyDisconnect,
+
+        SetAcceptPolicy,
+        SetAdvertiseData,
+
+        Ping = 254,
+        NetworkError = 255
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/PassphraseMessage.cs

@@ -0,0 +1,11 @@
+using Ryujinx.Common.Memory;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x80)]
+    struct PassphraseMessage
+    {
+        public Array128<byte> Passphrase;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/PingMessage.cs

@@ -0,0 +1,11 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x2)]
+    struct PingMessage
+    {
+        public byte Requester;
+        public byte Id;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ProxyConnectRequest.cs

@@ -0,0 +1,10 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x10)]
+    struct ProxyConnectRequest
+    {
+        public ProxyInfo Info;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ProxyConnectResponse.cs

@@ -0,0 +1,10 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x10)]
+    struct ProxyConnectResponse
+    {
+        public ProxyInfo Info;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ProxyDataHeader.cs

@@ -0,0 +1,14 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    /// <summary>
+    /// Represents data sent over a transport layer.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Size = 0x14)]
+    struct ProxyDataHeader
+    {
+        public ProxyInfo Info;
+        public uint DataLength; // Followed by the data with the specified byte length.
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ProxyDataPacket.cs

@@ -0,0 +1,8 @@
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    class ProxyDataPacket
+    {
+        public ProxyDataHeader Header;
+        public byte[] Data;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ProxyDisconnectMessage.cs

@@ -0,0 +1,11 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x14)]
+    struct ProxyDisconnectMessage
+    {
+        public ProxyInfo Info;
+        public int DisconnectReason;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/ProxyInfo.cs

@@ -0,0 +1,20 @@
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    /// <summary>
+    /// Information included in all proxied communication.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Size = 0x10, Pack = 1)]
+    struct ProxyInfo
+    {
+        public uint SourceIpV4;
+        public ushort SourcePort;
+
+        public uint DestIpV4;
+        public ushort DestPort;
+
+        public ProtocolType Protocol;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/RejectRequest.cs

@@ -0,0 +1,18 @@
+using Ryujinx.HLE.HOS.Services.Ldn.Types;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x8)]
+    struct RejectRequest
+    {
+        public uint NodeId;
+        public DisconnectReason DisconnectReason;
+
+        public RejectRequest(DisconnectReason disconnectReason, uint nodeId)
+        {
+            DisconnectReason = disconnectReason;
+            NodeId = nodeId;
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/RyuNetworkConfig.cs

@@ -0,0 +1,23 @@
+using Ryujinx.Common.Memory;
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x28, Pack = 1)]
+    struct RyuNetworkConfig
+    {
+        public Array16<byte> GameVersion;
+
+        // PrivateIp is included for external proxies for the case where a client attempts to join from
+        // their own LAN. UPnP forwarding can fail when connecting devices on the same network over the public IP,
+        // so if their public IP is identical, the internal address should be sent instead.
+
+        // The fields below are 0 if not hosting a p2p proxy.
+
+        public Array16<byte> PrivateIp;
+        public AddressFamily AddressFamily;
+        public ushort ExternalProxyPort;
+        public ushort InternalProxyPort;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/LdnRyu/Types/SetAcceptPolicyRequest.cs

@@ -0,0 +1,11 @@
+using Ryujinx.HLE.HOS.Services.Ldn.Types;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x1, Pack = 1)]
+    struct SetAcceptPolicyRequest
+    {
+        public AcceptPolicy StationAcceptPolicy;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/Station.cs

@@ -14,6 +14,8 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
 
         public bool Connected { get; private set; }
 
+        public ProxyConfig Config => _parent.NetworkClient.Config;
+
         public Station(IUserLocalCommunicationService parent)
         {
             _parent = parent;
@@ -47,11 +49,14 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator
         }
 
         public void Dispose()
+        {
+            if (_parent.NetworkClient != null)
             {
                 _parent.NetworkClient.DisconnectNetwork();
 
                 _parent.NetworkClient.NetworkChange -= NetworkChanged;
             }
+        }
 
         private ResultCode NetworkErrorToResult(NetworkError error)
         {

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/Types/CreateAccessPointPrivateRequest.cs

@@ -1,4 +1,5 @@
 using Ryujinx.HLE.HOS.Services.Ldn.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
 using System.Runtime.InteropServices;
 
 namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types
@@ -14,5 +15,7 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types
         public UserConfig UserConfig;
         public NetworkConfig NetworkConfig;
         public AddressList AddressList;
+
+        public RyuNetworkConfig RyuNetworkConfig;
     }
 }

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/Types/CreateAccessPointRequest.cs

@@ -1,4 +1,5 @@
 using Ryujinx.HLE.HOS.Services.Ldn.Types;
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Types;
 using System.Runtime.InteropServices;
 
 namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types
@@ -6,11 +7,13 @@ namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types
     /// <remarks>
     /// Advertise data is appended separately (remaining data in the buffer).
     /// </remarks>
-    [StructLayout(LayoutKind.Sequential, Size = 0x94, CharSet = CharSet.Ansi)]
+    [StructLayout(LayoutKind.Sequential, Size = 0xBC, Pack = 1)]
     struct CreateAccessPointRequest
     {
         public SecurityConfig SecurityConfig;
         public UserConfig UserConfig;
         public NetworkConfig NetworkConfig;
+
+        public RyuNetworkConfig RyuNetworkConfig;
     }
 }

src/Ryujinx.HLE/HOS/Services/Ldn/UserServiceCreator/Types/ProxyConfig.cs

@@ -0,0 +1,11 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.Types
+{
+    [StructLayout(LayoutKind.Sequential, Size = 0x8)]
+    struct ProxyConfig
+    {
+        public uint ProxyIp;
+        public uint ProxySubnetMask;
+    }
+}

src/Ryujinx.HLE/HOS/Services/Sockets/Bsd/IClient.cs

@@ -95,7 +95,7 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd
                 }
             }
 
-            ISocket newBsdSocket = new ManagedSocket(netDomain, (SocketType)type, protocol)
+            ISocket newBsdSocket = new ManagedSocket(netDomain, (SocketType)type, protocol, context.Device.Configuration.MultiplayerLanInterfaceId)
             {
                 Blocking = !creationFlags.HasFlag(BsdSocketCreationFlags.NonBlocking),
             };

src/Ryujinx.HLE/HOS/Services/Sockets/Bsd/Impl/ManagedSocket.cs

@@ -1,4 +1,5 @@
 using Ryujinx.Common.Logging;
+using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy;
 using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Types;
 using System;
 using System.Collections.Generic;
@@ -21,21 +22,21 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
 
         public bool Blocking { get => Socket.Blocking; set => Socket.Blocking = value; }
 
-        public nint Handle => Socket.Handle;
+        public nint Handle => IntPtr.Zero;
 
         public IPEndPoint RemoteEndPoint => Socket.RemoteEndPoint as IPEndPoint;
 
         public IPEndPoint LocalEndPoint => Socket.LocalEndPoint as IPEndPoint;
 
-        public Socket Socket { get; }
+        public ISocketImpl Socket { get; }
 
-        public ManagedSocket(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType)
+        public ManagedSocket(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType, string lanInterfaceId)
         {
-            Socket = new Socket(addressFamily, socketType, protocolType);
+            Socket = SocketHelpers.CreateSocket(addressFamily, socketType, protocolType, lanInterfaceId);
             Refcount = 1;
         }
 
-        private ManagedSocket(Socket socket)
+        private ManagedSocket(ISocketImpl socket)
         {
             Socket = socket;
             Refcount = 1;
@@ -185,6 +186,8 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
             }
         }
 
+        bool hasEmittedBlockingWarning = false;
+
         public LinuxError Receive(out int receiveSize, Span<byte> buffer, BsdSocketFlags flags)
         {
             LinuxError result;
@@ -199,6 +202,12 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
                     shouldBlockAfterOperation = true;
                 }
 
+                if (Blocking && !hasEmittedBlockingWarning)
+                {
+                    Logger.Warning?.PrintMsg(LogClass.ServiceBsd, "Blocking socket operations are not yet working properly. Expect network errors.");
+                    hasEmittedBlockingWarning = true;
+                }
+
                 receiveSize = Socket.Receive(buffer, ConvertBsdSocketFlags(flags));
 
                 result = LinuxError.SUCCESS;
@@ -236,6 +245,12 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
                     shouldBlockAfterOperation = true;
                 }
 
+                if (Blocking && !hasEmittedBlockingWarning)
+                {
+                    Logger.Warning?.PrintMsg(LogClass.ServiceBsd, "Blocking socket operations are not yet working properly. Expect network errors.");
+                    hasEmittedBlockingWarning = true;
+                }
+
                 if (!Socket.IsBound)
                 {
                     receiveSize = -1;
@@ -313,7 +328,7 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
                     Logger.Warning?.Print(LogClass.ServiceBsd, $"Unsupported GetSockOpt Option: {option} Level: {level}");
                     optionValue.Clear();
 
-                    return LinuxError.SUCCESS;
+                    return LinuxError.EOPNOTSUPP;
                 }
 
                 byte[] tempOptionValue = new byte[optionValue.Length];
@@ -347,7 +362,7 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
                 {
                     Logger.Warning?.Print(LogClass.ServiceBsd, $"Unsupported SetSockOpt Option: {option} Level: {level}");
 
-                    return LinuxError.SUCCESS;
+                    return LinuxError.EOPNOTSUPP;
                 }
 
                 int value = optionValue.Length >= 4 ? MemoryMarshal.Read<int>(optionValue) : MemoryMarshal.Read<byte>(optionValue);
@@ -493,7 +508,7 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
 
             try
             {
-                int receiveSize = Socket.Receive(ConvertMessagesToBuffer(message), ConvertBsdSocketFlags(flags), out SocketError socketError);
+                int receiveSize = (Socket as DefaultSocket).BaseSocket.Receive(ConvertMessagesToBuffer(message), ConvertBsdSocketFlags(flags), out SocketError socketError);
 
                 if (receiveSize > 0)
                 {
@@ -531,7 +546,7 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
 
             try
             {
-                int sendSize = Socket.Send(ConvertMessagesToBuffer(message), ConvertBsdSocketFlags(flags), out SocketError socketError);
+                int sendSize = (Socket as DefaultSocket).BaseSocket.Send(ConvertMessagesToBuffer(message), ConvertBsdSocketFlags(flags), out SocketError socketError);
 
                 if (sendSize > 0)
                 {

src/Ryujinx.HLE/HOS/Services/Sockets/Bsd/Impl/ManagedSocketPollManager.cs

@@ -1,4 +1,5 @@
 using Ryujinx.Common.Logging;
+using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy;
 using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Types;
 using System.Collections.Generic;
 using System.Net.Sockets;
@@ -26,37 +27,37 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
 
         public LinuxError Poll(List<PollEvent> events, int timeoutMilliseconds, out int updatedCount)
         {
-            List<Socket> readEvents = new();
+            List<ISocketImpl> readEvents = new();
-            List<Socket> writeEvents = new();
+            List<ISocketImpl> writeEvents = new();
-            List<Socket> errorEvents = new();
+            List<ISocketImpl> errorEvents = new();
 
             updatedCount = 0;
 
             foreach (PollEvent evnt in events)
             {
-                ManagedSocket socket = (ManagedSocket)evnt.FileDescriptor;
+                if (evnt.FileDescriptor is ManagedSocket ms)
-
+                {
                     bool isValidEvent = evnt.Data.InputEvents == 0;
 
-                errorEvents.Add(socket.Socket);
+                    errorEvents.Add(ms.Socket);
 
                     if ((evnt.Data.InputEvents & PollEventTypeMask.Input) != 0)
                     {
-                    readEvents.Add(socket.Socket);
+                        readEvents.Add(ms.Socket);
 
                         isValidEvent = true;
                     }
 
                     if ((evnt.Data.InputEvents & PollEventTypeMask.UrgentInput) != 0)
                     {
-                    readEvents.Add(socket.Socket);
+                        readEvents.Add(ms.Socket);
 
                         isValidEvent = true;
                     }
 
                     if ((evnt.Data.InputEvents & PollEventTypeMask.Output) != 0)
                     {
-                    writeEvents.Add(socket.Socket);
+                        writeEvents.Add(ms.Socket);
 
                         isValidEvent = true;
                     }
@@ -67,12 +68,13 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
                         return LinuxError.EINVAL;
                     }
                 }
+            }
 
             try
             {
                 int actualTimeoutMicroseconds = timeoutMilliseconds == -1 ? -1 : timeoutMilliseconds * 1000;
 
-                Socket.Select(readEvents, writeEvents, errorEvents, actualTimeoutMicroseconds);
+                SocketHelpers.Select(readEvents, writeEvents, errorEvents, actualTimeoutMicroseconds);
             }
             catch (SocketException exception)
             {
@@ -81,11 +83,13 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
 
             foreach (PollEvent evnt in events)
             {
-                Socket socket = ((ManagedSocket)evnt.FileDescriptor).Socket;
+                if (evnt.FileDescriptor is ManagedSocket ms)
+                {
+                    ISocketImpl socket = ms.Socket;
 
                     PollEventTypeMask outputEvents = evnt.Data.OutputEvents & ~evnt.Data.InputEvents;
 
-                if (errorEvents.Contains(socket))
+                    if (errorEvents.Contains(ms.Socket))
                     {
                         outputEvents |= PollEventTypeMask.Error;
 
@@ -95,7 +99,7 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
                         }
                     }
 
-                if (readEvents.Contains(socket))
+                    if (readEvents.Contains(ms.Socket))
                     {
                         if ((evnt.Data.InputEvents & PollEventTypeMask.Input) != 0)
                         {
@@ -103,13 +107,14 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
                         }
                     }
 
-                if (writeEvents.Contains(socket))
+                    if (writeEvents.Contains(ms.Socket))
                     {
                         outputEvents |= PollEventTypeMask.Output;
                     }
 
                     evnt.Data.OutputEvents = outputEvents;
                 }
+            }
 
             updatedCount = readEvents.Count + writeEvents.Count + errorEvents.Count;
 
@@ -118,55 +123,57 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl
 
         public LinuxError Select(List<PollEvent> events, int timeout, out int updatedCount)
         {
-            List<Socket> readEvents = new();
+            List<ISocketImpl> readEvents = new();
-            List<Socket> writeEvents = new();
+            List<ISocketImpl> writeEvents = new();
-            List<Socket> errorEvents = new();
+            List<ISocketImpl> errorEvents = new();
 
             updatedCount = 0;
 
             foreach (PollEvent pollEvent in events)
             {
-                ManagedSocket socket = (ManagedSocket)pollEvent.FileDescriptor;
+                if (pollEvent.FileDescriptor is ManagedSocket ms)
-
+                {
                     if (pollEvent.Data.InputEvents.HasFlag(PollEventTypeMask.Input))
                     {
-                    readEvents.Add(socket.Socket);
+                        readEvents.Add(ms.Socket);
                     }
 
                     if (pollEvent.Data.InputEvents.HasFlag(PollEventTypeMask.Output))
                     {
-                    writeEvents.Add(socket.Socket);
+                        writeEvents.Add(ms.Socket);
                     }
 
                     if (pollEvent.Data.InputEvents.HasFlag(PollEventTypeMask.Error))
                     {
-                    errorEvents.Add(socket.Socket);
+                        errorEvents.Add(ms.Socket);
+                    }
                 }
             }
 
-            Socket.Select(readEvents, writeEvents, errorEvents, timeout);
+            SocketHelpers.Select(readEvents, writeEvents, errorEvents, timeout);
 
             updatedCount = readEvents.Count + writeEvents.Count + errorEvents.Count;
 
             foreach (PollEvent pollEvent in events)
             {
-                ManagedSocket socket = (ManagedSocket)pollEvent.FileDescriptor;
+                if (pollEvent.FileDescriptor is ManagedSocket ms)
-
+                {
-                if (readEvents.Contains(socket.Socket))
+                    if (readEvents.Contains(ms.Socket))
                     {
                         pollEvent.Data.OutputEvents |= PollEventTypeMask.Input;
                     }
 
-                if (writeEvents.Contains(socket.Socket))
+                    if (writeEvents.Contains(ms.Socket))
                     {
                         pollEvent.Data.OutputEvents |= PollEventTypeMask.Output;
                     }
 
-                if (errorEvents.Contains(socket.Socket))
+                    if (errorEvents.Contains(ms.Socket))
                     {
                         pollEvent.Data.OutputEvents |= PollEventTypeMask.Error;
                     }
                 }
+            }
 
             return LinuxError.SUCCESS;
         }

src/Ryujinx.HLE/HOS/Services/Sockets/Bsd/Proxy/DefaultSocket.cs

@@ -0,0 +1,178 @@
+using Ryujinx.Common.Utilities;
+using System;
+using System.Net;
+using System.Net.NetworkInformation;
+using System.Net.Sockets;
+
+namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy
+{
+    class DefaultSocket : ISocketImpl
+    {
+        public Socket BaseSocket { get; }
+
+        public EndPoint RemoteEndPoint => BaseSocket.RemoteEndPoint;
+
+        public EndPoint LocalEndPoint => BaseSocket.LocalEndPoint;
+
+        public bool Connected => BaseSocket.Connected;
+
+        public bool IsBound => BaseSocket.IsBound;
+
+        public AddressFamily AddressFamily => BaseSocket.AddressFamily;
+
+        public SocketType SocketType => BaseSocket.SocketType;
+
+        public ProtocolType ProtocolType => BaseSocket.ProtocolType;
+
+        public bool Blocking { get => BaseSocket.Blocking; set => BaseSocket.Blocking = value; }
+
+        public int Available => BaseSocket.Available;
+
+        private readonly string _lanInterfaceId;
+
+        public DefaultSocket(Socket baseSocket, string lanInterfaceId)
+        {
+            _lanInterfaceId = lanInterfaceId;
+
+            BaseSocket = baseSocket;
+        }
+
+        public DefaultSocket(AddressFamily domain, SocketType type, ProtocolType protocol, string lanInterfaceId)
+        {
+            _lanInterfaceId = lanInterfaceId;
+
+            BaseSocket = new Socket(domain, type, protocol);
+        }
+
+        private void EnsureNetworkInterfaceBound()
+        {
+            if (_lanInterfaceId != "0" && !BaseSocket.IsBound)
+            {
+                (_, UnicastIPAddressInformation ipInfo) = NetworkHelpers.GetLocalInterface(_lanInterfaceId);
+
+                BaseSocket.Bind(new IPEndPoint(ipInfo.Address, 0));
+            }
+        }
+
+        public ISocketImpl Accept()
+        {
+            return new DefaultSocket(BaseSocket.Accept(), _lanInterfaceId);
+        }
+
+        public void Bind(EndPoint localEP)
+        {
+            // NOTE: The guest is able to receive on 0.0.0.0 without it being limited to the chosen network interface.
+            // This is because it must get loopback traffic as well. This could allow other network traffic to leak in.
+
+            BaseSocket.Bind(localEP);
+        }
+
+        public void Close()
+        {
+            BaseSocket.Close();
+        }
+
+        public void Connect(EndPoint remoteEP)
+        {
+            EnsureNetworkInterfaceBound();
+
+            BaseSocket.Connect(remoteEP);
+        }
+
+        public void Disconnect(bool reuseSocket)
+        {
+            BaseSocket.Disconnect(reuseSocket);
+        }
+
+        public void GetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, byte[] optionValue)
+        {
+            BaseSocket.GetSocketOption(optionLevel, optionName, optionValue);
+        }
+
+        public void Listen(int backlog)
+        {
+            BaseSocket.Listen(backlog);
+        }
+
+        public int Receive(Span<byte> buffer)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.Receive(buffer);
+        }
+
+        public int Receive(Span<byte> buffer, SocketFlags flags)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.Receive(buffer, flags);
+        }
+
+        public int Receive(Span<byte> buffer, SocketFlags flags, out SocketError socketError)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.Receive(buffer, flags, out socketError);
+        }
+
+        public int ReceiveFrom(Span<byte> buffer, SocketFlags flags, ref EndPoint remoteEP)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.ReceiveFrom(buffer, flags, ref remoteEP);
+        }
+
+        public int Send(ReadOnlySpan<byte> buffer)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.Send(buffer);
+        }
+
+        public int Send(ReadOnlySpan<byte> buffer, SocketFlags flags)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.Send(buffer, flags);
+        }
+
+        public int Send(ReadOnlySpan<byte> buffer, SocketFlags flags, out SocketError socketError)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.Send(buffer, flags, out socketError);
+        }
+
+        public int SendTo(ReadOnlySpan<byte> buffer, SocketFlags flags, EndPoint remoteEP)
+        {
+            EnsureNetworkInterfaceBound();
+
+            return BaseSocket.SendTo(buffer, flags, remoteEP);
+        }
+
+        public bool Poll(int microSeconds, SelectMode mode)
+        {
+            return BaseSocket.Poll(microSeconds, mode);
+        }
+
+        public void SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, int optionValue)
+        {
+            BaseSocket.SetSocketOption(optionLevel, optionName, optionValue);
+        }
+
+        public void SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, object optionValue)
+        {
+            BaseSocket.SetSocketOption(optionLevel, optionName, optionValue);
+        }
+
+        public void Shutdown(SocketShutdown how)
+        {
+            BaseSocket.Shutdown(how);
+        }
+
+        public void Dispose()
+        {
+            BaseSocket.Dispose();
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Sockets/Bsd/Proxy/ISocket.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Net;
+using System.Net.Sockets;
+
+namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy
+{
+    interface ISocketImpl : IDisposable
+    {
+        EndPoint RemoteEndPoint { get; }
+        EndPoint LocalEndPoint { get; }
+        bool Connected { get; }
+        bool IsBound { get; }
+
+        AddressFamily AddressFamily { get; }
+        SocketType SocketType { get; }
+        ProtocolType ProtocolType { get; }
+
+        bool Blocking { get; set; }
+        int Available { get; }
+
+        int Receive(Span<byte> buffer);
+        int Receive(Span<byte> buffer, SocketFlags flags);
+        int Receive(Span<byte> buffer, SocketFlags flags, out SocketError socketError);
+        int ReceiveFrom(Span<byte> buffer, SocketFlags flags, ref EndPoint remoteEP);
+
+        int Send(ReadOnlySpan<byte> buffer);
+        int Send(ReadOnlySpan<byte> buffer, SocketFlags flags);
+        int Send(ReadOnlySpan<byte> buffer, SocketFlags flags, out SocketError socketError);
+        int SendTo(ReadOnlySpan<byte> buffer, SocketFlags flags, EndPoint remoteEP);
+
+        bool Poll(int microSeconds, SelectMode mode);
+
+        ISocketImpl Accept();
+
+        void Bind(EndPoint localEP);
+        void Connect(EndPoint remoteEP);
+        void Listen(int backlog);
+
+        void GetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, byte[] optionValue);
+        void SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, int optionValue);
+        void SetSocketOption(SocketOptionLevel optionLevel, SocketOptionName optionName, object optionValue);
+
+        void Shutdown(SocketShutdown how);
+        void Disconnect(bool reuseSocket);
+        void Close();
+    }
+}

src/Ryujinx.HLE/HOS/Services/Sockets/Bsd/Proxy/SocketHelpers.cs

@@ -0,0 +1,74 @@
+using Ryujinx.HLE.HOS.Services.Ldn.UserServiceCreator.LdnRyu.Proxy;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Sockets;
+
+namespace Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy
+{
+    static class SocketHelpers
+    {
+        private static LdnProxy _proxy;
+
+        public static void Select(List<ISocketImpl> readEvents, List<ISocketImpl> writeEvents, List<ISocketImpl> errorEvents, int timeout)
+        {
+            var readDefault = readEvents.Select(x => (x as DefaultSocket)?.BaseSocket).Where(x => x != null).ToList();
+            var writeDefault = writeEvents.Select(x => (x as DefaultSocket)?.BaseSocket).Where(x => x != null).ToList();
+            var errorDefault = errorEvents.Select(x => (x as DefaultSocket)?.BaseSocket).Where(x => x != null).ToList();
+
+            if (readDefault.Count != 0 || writeDefault.Count != 0 || errorDefault.Count != 0)
+            {
+                Socket.Select(readDefault, writeDefault, errorDefault, timeout);
+            }
+
+            void FilterSockets(List<ISocketImpl> removeFrom, List<Socket> selectedSockets, Func<LdnProxySocket, bool> ldnCheck)
+            {
+                removeFrom.RemoveAll(socket =>
+                {
+                    switch (socket)
+                    {
+                        case DefaultSocket dsocket:
+                            return !selectedSockets.Contains(dsocket.BaseSocket);
+                        case LdnProxySocket psocket:
+                            return !ldnCheck(psocket);
+                        default:
+                            throw new NotImplementedException();
+                    }
+                });
+            };
+
+            FilterSockets(readEvents, readDefault, (socket) => socket.Readable);
+            FilterSockets(writeEvents, writeDefault, (socket) => socket.Writable);
+            FilterSockets(errorEvents, errorDefault, (socket) => socket.Error);
+        }
+
+        public static void RegisterProxy(LdnProxy proxy)
+        {
+            if (_proxy != null)
+            {
+                UnregisterProxy();
+            }
+
+            _proxy = proxy;
+        }
+
+        public static void UnregisterProxy()
+        {
+            _proxy?.Dispose();
+            _proxy = null;
+        }
+
+        public static ISocketImpl CreateSocket(AddressFamily domain, SocketType type, ProtocolType protocol, string lanInterfaceId)
+        {
+            if (_proxy != null)
+            {
+                if (_proxy.Supported(domain, type, protocol))
+                {
+                    return new LdnProxySocket(domain, type, protocol, _proxy);
+                }
+            }
+
+            return new DefaultSocket(domain, type, protocol, lanInterfaceId);
+        }
+    }
+}

src/Ryujinx.HLE/HOS/Services/Sockets/Sfdnsres/IResolver.cs

@@ -292,7 +292,7 @@ namespace Ryujinx.HLE.HOS.Services.Sockets.Sfdnsres
         {
             string host = MemoryHelper.ReadAsciiString(context.Memory, inputBufferPosition, (int)inputBufferSize);
 
-            if (!context.Device.Configuration.EnableInternetAccess)
+            if (host != "localhost" && !context.Device.Configuration.EnableInternetAccess)
             {
                 Logger.Info?.Print(LogClass.ServiceSfdnsres, $"Guest network access disabled, DNS Blocked: {host}");
 

src/Ryujinx.HLE/HOS/Services/Ssl/SslService/SslManagedSocketConnection.cs

@@ -1,5 +1,6 @@
 using Ryujinx.HLE.HOS.Services.Sockets.Bsd;
 using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Impl;
+using Ryujinx.HLE.HOS.Services.Sockets.Bsd.Proxy;
 using Ryujinx.HLE.HOS.Services.Ssl.Types;
 using System;
 using System.IO;
@@ -116,7 +117,7 @@ namespace Ryujinx.HLE.HOS.Services.Ssl.SslService
         public ResultCode Handshake(string hostName)
         {
             StartSslOperation();
-            _stream = new SslStream(new NetworkStream(((ManagedSocket)Socket).Socket, false), false, null, null);
+            _stream = new SslStream(new NetworkStream(((DefaultSocket)((ManagedSocket)Socket).Socket).BaseSocket, false), false, null, null);
             hostName = RetrieveHostName(hostName);
             _stream.AuthenticateAsClient(hostName, null, TranslateSslVersion(_sslVersion), false);
             EndSslOperation();

src/Ryujinx.HLE/Ryujinx.HLE.csproj

@@ -29,6 +29,7 @@
     <PackageReference Include="SkiaSharp" />
     <PackageReference Include="SkiaSharp.NativeAssets.Linux" />
     <PackageReference Include="NetCoreServer" />
+    <PackageReference Include="Open.NAT.Core" />
   </ItemGroup>
 
   <ItemGroup>

src/Ryujinx.Headless.SDL2/Program.cs

@@ -577,7 +577,10 @@ namespace Ryujinx.Headless.SDL2
                 options.AudioVolume,
                 options.UseHypervisor ?? true,
                 options.MultiplayerLanInterfaceId,
-                Common.Configuration.Multiplayer.MultiplayerMode.Disabled);
+                Common.Configuration.Multiplayer.MultiplayerMode.Disabled,
+                false,
+                "",
+                "");
 
             return new Switch(configuration);
         }

src/Ryujinx.UI.Common/App/ApplicationData.cs

@@ -27,6 +27,8 @@ namespace Ryujinx.UI.App.Common
         public ulong Id { get; set; }
         public string Developer { get; set; } = "Unknown";
         public string Version { get; set; } = "0";
+        public int PlayerCount { get; set; }
+        public int GameCount { get; set; }
         public TimeSpan TimePlayed { get; set; }
         public DateTime? LastPlayed { get; set; }
         public string FileExtension { get; set; }

src/Ryujinx.UI.Common/App/ApplicationLibrary.cs

@@ -12,6 +12,7 @@ using LibHac.Tools.Fs;
 using LibHac.Tools.FsSystem;
 using LibHac.Tools.FsSystem.NcaUtils;
 using Ryujinx.Common.Configuration;
+using Ryujinx.Common.Configuration.Multiplayer;
 using Ryujinx.Common.Logging;
 using Ryujinx.Common.Utilities;
 using Ryujinx.HLE.FileSystem;
@@ -27,10 +28,12 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Net.Http;
 using System.Reflection;
 using System.Text;
 using System.Text.Json;
 using System.Threading;
+using System.Threading.Tasks;
 using ContentType = LibHac.Ncm.ContentType;
 using MissingKeyException = LibHac.Common.Keys.MissingKeyException;
 using Path = System.IO.Path;
@@ -41,8 +44,10 @@ namespace Ryujinx.UI.App.Common
 {
     public class ApplicationLibrary
     {
+        public static string DefaultLanPlayWebHost = "ryuldnweb.vudjun.com";
         public Language DesiredLanguage { get; set; }
         public event EventHandler<ApplicationCountUpdatedEventArgs> ApplicationCountUpdated;
+        public event EventHandler<LdnGameDataReceivedEventArgs> LdnGameDataReceived;
 
         public readonly IObservableCache<ApplicationData, ulong> Applications;
         public readonly IObservableCache<(TitleUpdateModel TitleUpdate, bool IsSelected), TitleUpdateModel> TitleUpdates;
@@ -62,6 +67,7 @@ namespace Ryujinx.UI.App.Common
         private readonly SourceCache<(DownloadableContentModel Dlc, bool IsEnabled), DownloadableContentModel> _downloadableContents = new(it => it.Dlc);
 
         private static readonly ApplicationJsonSerializerContext _serializerContext = new(JsonHelper.GetDefaultSerializerOptions());
+        private static readonly LdnGameDataSerializerContext _ldnDataSerializerContext = new(JsonHelper.GetDefaultSerializerOptions());
 
         public ApplicationLibrary(VirtualFileSystem virtualFileSystem, IntegrityCheckLevel checkLevel)
         {
@@ -719,6 +725,7 @@ namespace Ryujinx.UI.App.Common
                     }
                 }
 
+
                 // Loops through applications list, creating a struct and then firing an event containing the struct for each application
                 foreach (string applicationPath in applicationPaths)
                 {
@@ -775,6 +782,46 @@ namespace Ryujinx.UI.App.Common
             }
         }
 
+        public async Task RefreshLdn()
+        {
+
+            if (ConfigurationState.Instance.Multiplayer.Mode == MultiplayerMode.LdnRyu)
+            {
+                try
+                {
+                    string ldnWebHost = ConfigurationState.Instance.Multiplayer.LdnServer;
+                    if (string.IsNullOrEmpty(ldnWebHost))
+                    {
+                        ldnWebHost = DefaultLanPlayWebHost;
+                    }
+                    IEnumerable<LdnGameData> ldnGameDataArray = Array.Empty<LdnGameData>();
+                    using HttpClient httpClient = new HttpClient();
+                    string ldnGameDataArrayString = await httpClient.GetStringAsync($"https://{ldnWebHost}/api/public_games");
+                    ldnGameDataArray = JsonHelper.Deserialize(ldnGameDataArrayString, _ldnDataSerializerContext.IEnumerableLdnGameData);
+                    var evt = new LdnGameDataReceivedEventArgs
+                    {
+                        LdnData = ldnGameDataArray
+                    };
+                    LdnGameDataReceived?.Invoke(null, evt);
+                }
+                catch (Exception ex)
+                {
+                    Logger.Warning?.Print(LogClass.Application, $"Failed to fetch the public games JSON from the API. Player and game count in the game list will be unavailable.\n{ex.Message}");
+                    LdnGameDataReceived?.Invoke(null, new LdnGameDataReceivedEventArgs()
+                    {
+                        LdnData = Array.Empty<LdnGameData>()
+                    });
+                }
+            }
+            else
+            {
+                LdnGameDataReceived?.Invoke(null, new LdnGameDataReceivedEventArgs()
+                {
+                    LdnData = Array.Empty<LdnGameData>()
+                });
+            }
+        }
+
         // Replace the currently stored DLC state for the game with the provided DLC state.
         public void SaveDownloadableContentsForGame(ApplicationData application, List<(DownloadableContentModel, bool IsEnabled)> dlcs)
         {

src/Ryujinx.UI.Common/App/LdnGameData.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+
+namespace Ryujinx.UI.App.Common
+{
+    public struct LdnGameData
+    {
+        public string Id { get; set; }
+        public int PlayerCount { get; set; }
+        public int MaxPlayerCount { get; set; }
+        public string GameName { get; set; }
+        public string TitleId { get; set; }
+        public string Mode { get; set; }
+        public string Status { get; set; }
+        public IEnumerable<string> Players { get; set; }
+    }
+}

src/Ryujinx.UI.Common/App/LdnGameDataReceivedEventArgs.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+
+namespace Ryujinx.UI.App.Common
+{
+    public class LdnGameDataReceivedEventArgs : EventArgs
+    {
+        public IEnumerable<LdnGameData> LdnData { get; set; }
+    }
+}

src/Ryujinx.UI.Common/App/LdnGameDataSerializerContext.cs

@@ -0,0 +1,11 @@
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace Ryujinx.UI.App.Common
+{
+    [JsonSerializable(typeof(IEnumerable<LdnGameData>))]
+    internal partial class LdnGameDataSerializerContext : JsonSerializerContext
+    {
+
+    }
+}

src/Ryujinx.UI.Common/Configuration/ConfigurationFileFormat.cs

@@ -392,6 +392,21 @@ namespace Ryujinx.UI.Common.Configuration
         /// </summary>
         public string MultiplayerLanInterfaceId { get; set; }
 
+        /// <summary>
+        /// Disable P2p Toggle
+        /// </summary>
+        public bool MultiplayerDisableP2p { get; set; }
+
+        /// <summary>
+        /// Local network passphrase, for private networks.
+        /// </summary>
+        public string MultiplayerLdnPassphrase { get; set; }
+
+        /// <summary>
+        /// Custom LDN Server
+        /// </summary>
+        public string LdnServer { get; set; }
+
         /// <summary>
         /// Uses Hypervisor over JIT if available
         /// </summary>

src/Ryujinx.UI.Common/Configuration/ConfigurationState.Migration.cs

@@ -1,4 +1,4 @@
-using Ryujinx.Common.Configuration;
+using Ryujinx.Common.Configuration;
 using Ryujinx.Common.Configuration.Hid;
 using Ryujinx.Common.Configuration.Hid.Controller;
 using Ryujinx.Common.Configuration.Hid.Keyboard;
@@ -703,6 +703,9 @@ namespace Ryujinx.UI.Common.Configuration
 
             Multiplayer.LanInterfaceId.Value = configurationFileFormat.MultiplayerLanInterfaceId;
             Multiplayer.Mode.Value = configurationFileFormat.MultiplayerMode;
+            Multiplayer.DisableP2p.Value = configurationFileFormat.MultiplayerDisableP2p;
+            Multiplayer.LdnPassphrase.Value = configurationFileFormat.MultiplayerLdnPassphrase;
+            Multiplayer.LdnServer.Value = configurationFileFormat.LdnServer;
 
             if (configurationFileUpdated)
             {

src/Ryujinx.UI.Common/Configuration/ConfigurationState.Model.cs

@@ -25,6 +25,7 @@ namespace Ryujinx.UI.Common.Configuration
                 public ReactiveObject<bool> AppColumn { get; private set; }
                 public ReactiveObject<bool> DevColumn { get; private set; }
                 public ReactiveObject<bool> VersionColumn { get; private set; }
+                public ReactiveObject<bool> LdnInfoColumn { get; private set; }
                 public ReactiveObject<bool> TimePlayedColumn { get; private set; }
                 public ReactiveObject<bool> LastPlayedColumn { get; private set; }
                 public ReactiveObject<bool> FileExtColumn { get; private set; }
@@ -38,6 +39,7 @@ namespace Ryujinx.UI.Common.Configuration
                     AppColumn = new ReactiveObject<bool>();
                     DevColumn = new ReactiveObject<bool>();
                     VersionColumn = new ReactiveObject<bool>();
+                    LdnInfoColumn = new ReactiveObject<bool>();
                     TimePlayedColumn = new ReactiveObject<bool>();
                     LastPlayedColumn = new ReactiveObject<bool>();
                     FileExtColumn = new ReactiveObject<bool>();
@@ -572,11 +574,32 @@ namespace Ryujinx.UI.Common.Configuration
             /// </summary>
             public ReactiveObject<MultiplayerMode> Mode { get; private set; }
 
+            /// <summary>
+            /// Disable P2P
+            /// </summary>
+            public ReactiveObject<bool> DisableP2p { get; private set; }
+
+            /// <summary>
+            /// LDN PassPhrase
+            /// </summary>
+            public ReactiveObject<string> LdnPassphrase { get; private set; }
+
+            /// <summary>
+            /// LDN Server
+            /// </summary>
+            public ReactiveObject<string> LdnServer { get; private set; }
+
             public MultiplayerSection()
             {
                 LanInterfaceId = new ReactiveObject<string>();
                 Mode = new ReactiveObject<MultiplayerMode>();
                 Mode.LogChangesToValue(nameof(MultiplayerMode));
+                DisableP2p = new ReactiveObject<bool>();
+                DisableP2p.LogChangesToValue(nameof(DisableP2p));
+                LdnPassphrase = new ReactiveObject<string>();
+                LdnPassphrase.LogChangesToValue(nameof(LdnPassphrase));
+                LdnServer = new ReactiveObject<string>();
+                LdnServer.LogChangesToValue(nameof(LdnServer));
             }
         }
 

src/Ryujinx.UI.Common/Configuration/ConfigurationState.cs

@@ -87,6 +87,7 @@ namespace Ryujinx.UI.Common.Configuration
                     AppColumn = UI.GuiColumns.AppColumn,
                     DevColumn = UI.GuiColumns.DevColumn,
                     VersionColumn = UI.GuiColumns.VersionColumn,
+                    LdnInfoColumn = UI.GuiColumns.LdnInfoColumn,
                     TimePlayedColumn = UI.GuiColumns.TimePlayedColumn,
                     LastPlayedColumn = UI.GuiColumns.LastPlayedColumn,
                     FileExtColumn = UI.GuiColumns.FileExtColumn,
@@ -136,6 +137,9 @@ namespace Ryujinx.UI.Common.Configuration
                 PreferredGpu = Graphics.PreferredGpu,
                 MultiplayerLanInterfaceId = Multiplayer.LanInterfaceId,
                 MultiplayerMode = Multiplayer.Mode,
+                MultiplayerDisableP2p = Multiplayer.DisableP2p,
+                MultiplayerLdnPassphrase = Multiplayer.LdnPassphrase,
+                LdnServer = Multiplayer.LdnServer,
             };
 
             return configurationFile;
@@ -195,6 +199,9 @@ namespace Ryujinx.UI.Common.Configuration
             System.UseHypervisor.Value = true;
             Multiplayer.LanInterfaceId.Value = "0";
             Multiplayer.Mode.Value = MultiplayerMode.Disabled;
+            Multiplayer.DisableP2p.Value = false;
+            Multiplayer.LdnPassphrase.Value = "";
+            Multiplayer.LdnServer.Value = "";
             UI.GuiColumns.FavColumn.Value = true;
             UI.GuiColumns.IconColumn.Value = true;
             UI.GuiColumns.AppColumn.Value = true;
@@ -308,4 +315,4 @@ namespace Ryujinx.UI.Common.Configuration
             return GraphicsBackend.OpenGl;
         }
             }
-}
+        }

src/Ryujinx.UI.Common/Configuration/UI/GuiColumns.cs

@@ -7,6 +7,7 @@ namespace Ryujinx.UI.Common.Configuration.UI
         public bool AppColumn { get; set; }
         public bool DevColumn { get; set; }
         public bool VersionColumn { get; set; }
+        public bool LdnInfoColumn { get; set; }
         public bool TimePlayedColumn { get; set; }
         public bool LastPlayedColumn { get; set; }
         public bool FileExtColumn { get; set; }

src/Ryujinx/AppHost.cs

@@ -207,6 +207,9 @@ namespace Ryujinx.Ava
             ConfigurationState.Instance.System.EnableInternetAccess.Event += UpdateEnableInternetAccessState;
             ConfigurationState.Instance.Multiplayer.LanInterfaceId.Event += UpdateLanInterfaceIdState;
             ConfigurationState.Instance.Multiplayer.Mode.Event += UpdateMultiplayerModeState;
+            ConfigurationState.Instance.Multiplayer.LdnPassphrase.Event += UpdateLdnPassphraseState;
+            ConfigurationState.Instance.Multiplayer.LdnServer.Event += UpdateLdnServerState;
+            ConfigurationState.Instance.Multiplayer.DisableP2p.Event += UpdateDisableP2pState;
 
             _gpuCancellationTokenSource = new CancellationTokenSource();
             _gpuDoneEvent = new ManualResetEvent(false);
@@ -491,6 +494,21 @@ namespace Ryujinx.Ava
             Device.Configuration.MultiplayerMode = e.NewValue;
         }
 
+        private void UpdateLdnPassphraseState(object sender, ReactiveEventArgs<string> e)
+        {
+            Device.Configuration.MultiplayerLdnPassphrase = e.NewValue;
+        }
+
+        private void UpdateLdnServerState(object sender, ReactiveEventArgs<string> e)
+        {
+            Device.Configuration.MultiplayerLdnServer = e.NewValue;
+        }
+
+        private void UpdateDisableP2pState(object sender, ReactiveEventArgs<bool> e)
+        {
+            Device.Configuration.MultiplayerDisableP2p = e.NewValue;
+        }
+
         public void ToggleVSync()
         {
             Device.EnableDeviceVsync = !Device.EnableDeviceVsync;
@@ -863,10 +881,11 @@ namespace Ryujinx.Ava
                 ConfigurationState.Instance.Graphics.AspectRatio,
                 ConfigurationState.Instance.System.AudioVolume,
                 ConfigurationState.Instance.System.UseHypervisor,
-                ConfigurationState.Instance.Multiplayer.LanInterfaceId,
+                ConfigurationState.Instance.Multiplayer.LanInterfaceId.Value,
-                ConfigurationState.Instance.Multiplayer.Mode
+                ConfigurationState.Instance.Multiplayer.Mode,
-                )
+                ConfigurationState.Instance.Multiplayer.DisableP2p,
-            );
+                ConfigurationState.Instance.Multiplayer.LdnPassphrase,
+                ConfigurationState.Instance.Multiplayer.LdnServer));
         }
 
         private static IHardwareDeviceDriver InitializeAudio()

src/Ryujinx/Assets/Locales/en_US.json

@@ -848,5 +848,17 @@
   "MultiplayerMode": "Mode:",
   "MultiplayerModeTooltip": "Change LDN multiplayer mode.\n\nLdnMitm will modify local wireless/local play functionality in games to function as if it were LAN, allowing for local, same-network connections with other Ryujinx instances and hacked Nintendo Switch consoles that have the ldn_mitm module installed.\n\nMultiplayer requires all players to be on the same game version (i.e. Super Smash Bros. Ultimate v13.0.1 can't connect to v13.0.0).\n\nLeave DISABLED if unsure.",
   "MultiplayerModeDisabled": "Disabled",
-  "MultiplayerModeLdnMitm": "ldn_mitm"
+  "MultiplayerModeLdnMitm": "ldn_mitm",
+  "MultiplayerModeLdnRyu": "RyuLDN",
+  "MultiplayerDisableP2P": "Disable P2P Network Hosting (may increase latency)",
+  "MultiplayerDisableP2PTooltip": "Disable P2P network hosting, peers will proxy through the master server instead of connecting to you directly.",
+  "LdnPassphrase": "Network Passphrase:",
+  "LdnPassphraseTooltip": "You will only be able to see hosted games with the same passphrase as you.",
+  "LdnPassphraseInputTooltip": "Enter a passphrase in the format Ryujinx-<8 hex chars>. You will only be able to see hosted games with the same passphrase as you.",
+  "LdnPassphraseInputPublic": "(public)",
+  "GenLdnPass": "Generate Random",
+  "GenLdnPassTooltip": "Generates a new passphrase, which can be shared with other players.",
+  "ClearLdnPass": "Clear",
+  "ClearLdnPassTooltip": "Clears the current passphrase, returning to the public network.",
+  "InvalidLdnPassphrase": "Invalid Passphrase! Must be in the format \"Ryujinx-<8 hex chars>\""
 }

src/Ryujinx/Program.cs

@@ -229,11 +229,9 @@ namespace Ryujinx.Ava
 
             var enabledLogLevels = Logger.GetEnabledLevels().ToArray();
 
-            Logger.Notice.Print(LogClass.Application, $"Logs Enabled: {
+            Logger.Notice.Print(LogClass.Application, $"Logs Enabled: {(enabledLogLevels.Length is 0
-                (enabledLogLevels.Length is 0
                     ? "<None>"
-                    : enabledLogLevels.JoinToString(", "))
+                    : enabledLogLevels.JoinToString(", "))}");
-            }");
 
             Logger.Notice.Print(LogClass.Application,
                 AppDataManager.Mode == AppDataManager.LaunchMode.Custom
@@ -247,7 +245,7 @@ namespace Ryujinx.Ava
             string message = $"Unhandled exception caught: {ex}";
 
             // ReSharper disable once ConstantConditionalAccessQualifier
-            if (sender?.GetType()?.AsPrettyString() is {} senderName)
+            if (sender?.GetType()?.AsPrettyString() is { } senderName)
                 log.Print(LogClass.Application, message, senderName);
             else
                 log.PrintMsg(LogClass.Application, message);

src/Ryujinx/UI/Controls/ApplicationListView.axaml

@@ -7,6 +7,7 @@
     xmlns:helpers="clr-namespace:Ryujinx.Ava.UI.Helpers"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:ui="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia"
+    xmlns:converters="clr-namespace:Avalonia.Data.Converters;assembly=Avalonia.Base"
     d:DesignHeight="450"
     d:DesignWidth="800"
     Focusable="True"
@@ -110,6 +111,11 @@
                                         Text="{Binding FileExtension}"
                                         TextAlignment="Start"
                                         TextWrapping="Wrap" />
+                                    <TextBlock
+                                        HorizontalAlignment="Stretch"
+                                        Text="{Binding Converter={helpers:MultiplayerInfoConverter}}"
+                                        TextAlignment="Start"
+                                        TextWrapping="Wrap"/>
                                 </StackPanel>
                                 <StackPanel
                                     Grid.Column="4"

src/Ryujinx/UI/Helpers/MultiplayerInfoConverter.cs

@@ -0,0 +1,44 @@
+using Avalonia.Data.Converters;
+using Avalonia.Markup.Xaml;
+using Ryujinx.Ava.Common.Locale;
+using Ryujinx.UI.App.Common;
+using Ryujinx.UI.Common.Helper;
+using System;
+using System.Globalization;
+
+namespace Ryujinx.Ava.UI.Helpers
+{
+    internal class MultiplayerInfoConverter : MarkupExtension, IValueConverter
+    {
+        private static readonly MultiplayerInfoConverter _instance = new();
+
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (value is ApplicationData applicationData)
+            {
+                if (applicationData.PlayerCount != 0 && applicationData.GameCount != 0)
+                {
+                    return $"Hosted Games: {applicationData.GameCount}\nOnline Players: {applicationData.PlayerCount}";
+                }
+                else
+                {
+                    return "";
+                }
+            }
+            else
+            {
+                return "";
+            }
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override object ProvideValue(IServiceProvider serviceProvider)
+        {
+            return _instance;
+        }
+    }
+}

src/Ryujinx/UI/ViewModels/MainWindowViewModel.cs

@@ -117,6 +117,8 @@ namespace Ryujinx.Ava.UI.ViewModels
         public ApplicationData ListSelectedApplication;
         public ApplicationData GridSelectedApplication;
 
+        public IEnumerable<LdnGameData> LastLdnGameData;
+
         public static readonly Bitmap IconBitmap =
             new(Assembly.GetAssembly(typeof(ConfigurationState))!.GetManifestResourceStream("Ryujinx.UI.Common.Resources.Logo_Ryujinx.png")!);
 

src/Ryujinx/UI/ViewModels/SettingsViewModel.cs

@@ -25,12 +25,13 @@ using System.Collections.ObjectModel;
 using System.Linq;
 using System.Net.NetworkInformation;
 using System.Runtime.InteropServices;
+using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 using TimeZone = Ryujinx.Ava.UI.Models.TimeZone;
 
 namespace Ryujinx.Ava.UI.ViewModels
 {
-    public class SettingsViewModel : BaseModel
+    public partial class SettingsViewModel : BaseModel
     {
         private readonly VirtualFileSystem _virtualFileSystem;
         private readonly ContentManager _contentManager;
@@ -56,6 +57,8 @@ namespace Ryujinx.Ava.UI.ViewModels
         public event Action SaveSettingsEvent;
         private int _networkInterfaceIndex;
         private int _multiplayerModeIndex;
+        private string _ldnPassphrase;
+        private string _LdnServer;
 
         public int ResolutionScale
         {
@@ -180,10 +183,24 @@ namespace Ryujinx.Ava.UI.ViewModels
 
         public bool IsVulkanSelected => GraphicsBackendIndex == 0;
         public bool UseHypervisor { get; set; }
+        public bool DisableP2P { get; set; }
 
         public string TimeZone { get; set; }
         public string ShaderDumpPath { get; set; }
 
+        public string LdnPassphrase
+        {
+            get => _ldnPassphrase;
+            set
+            {
+                _ldnPassphrase = value;
+                IsInvalidLdnPassphraseVisible = !ValidateLdnPassphrase(value);
+
+                OnPropertyChanged();
+                OnPropertyChanged(nameof(IsInvalidLdnPassphraseVisible));
+            }
+        }
+
         public int Language { get; set; }
         public int Region { get; set; }
         public int FsGlobalAccessLogMode { get; set; }
@@ -276,6 +293,21 @@ namespace Ryujinx.Ava.UI.ViewModels
             }
         }
 
+        [GeneratedRegex("Ryujinx-[0-9a-f]{8}")]
+        private static partial Regex LdnPassphraseRegex();
+
+        public bool IsInvalidLdnPassphraseVisible { get; set; }
+
+        public string LdnServer
+        {
+            get => _LdnServer;
+            set
+            {
+                _LdnServer = value;
+                OnPropertyChanged();
+            }
+        }
+
         public SettingsViewModel(VirtualFileSystem virtualFileSystem, ContentManager contentManager) : this()
         {
             _virtualFileSystem = virtualFileSystem;
@@ -393,6 +425,11 @@ namespace Ryujinx.Ava.UI.ViewModels
             Dispatcher.UIThread.Post(() => OnPropertyChanged(nameof(NetworkInterfaceIndex)));
         }
 
+        private bool ValidateLdnPassphrase(string passphrase)
+        {
+            return string.IsNullOrEmpty(passphrase) || (passphrase.Length == 16 && LdnPassphraseRegex().IsMatch(passphrase));
+        }
+
         public void ValidateAndSetTimeZone(string location)
         {
             if (_validTzRegions.Contains(location))
@@ -497,6 +534,9 @@ namespace Ryujinx.Ava.UI.ViewModels
             OpenglDebugLevel = (int)config.Logger.GraphicsDebugLevel.Value;
 
             MultiplayerModeIndex = (int)config.Multiplayer.Mode.Value;
+            DisableP2P = config.Multiplayer.DisableP2p.Value;
+            LdnPassphrase = config.Multiplayer.LdnPassphrase.Value;
+            LdnServer = config.Multiplayer.LdnServer.Value;
         }
 
         public void SaveSettings()
@@ -613,6 +653,9 @@ namespace Ryujinx.Ava.UI.ViewModels
 
             config.Multiplayer.LanInterfaceId.Value = _networkInterfaces[NetworkInterfaceList[NetworkInterfaceIndex]];
             config.Multiplayer.Mode.Value = (MultiplayerMode)MultiplayerModeIndex;
+            config.Multiplayer.DisableP2p.Value = DisableP2P;
+            config.Multiplayer.LdnPassphrase.Value = LdnPassphrase;
+            config.Multiplayer.LdnServer.Value = LdnServer;
 
             config.ToFileFormat().SaveConfig(Program.ConfigurationPath);
 

src/Ryujinx/UI/Views/Settings/SettingsNetworkView.axaml

@@ -1,4 +1,4 @@
-<UserControl
+<UserControl
     x:Class="Ryujinx.Ava.UI.Views.Settings.SettingsNetworkView"
     xmlns="https://github.com/avaloniaui"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
@@ -36,11 +36,57 @@
                         <ComboBoxItem>
                             <TextBlock Text="{ext:Locale MultiplayerModeDisabled}" />
                         </ComboBoxItem>
+                        <ComboBoxItem>
+                            <TextBlock Text="{ext:Locale MultiplayerModeLdnRyu}" />
+                        </ComboBoxItem>
                         <ComboBoxItem>
                             <TextBlock Text="{ext:Locale MultiplayerModeLdnMitm}" />
                         </ComboBoxItem>
                     </ComboBox>
+                    <CheckBox Margin="10,0,0,0" IsChecked="{Binding DisableP2P}">
+                        <TextBlock Text="{ext:Locale MultiplayerDisableP2P}"
+                            ToolTip.Tip="{ext:Locale MultiplayerDisableP2PTooltip}" />
+                    </CheckBox>
                 </StackPanel>
+                <StackPanel Margin="10,0,0,0" Orientation="Horizontal">
+                    <TextBlock VerticalAlignment="Center"
+                        Text="{ext:Locale LdnPassphrase}"
+                        ToolTip.Tip="{ext:Locale LdnPassphraseTooltip}"
+                        Width="200" />
+                    <TextBox Name="LdnPassphrase"
+                        Text="{Binding LdnPassphrase}"
+                        Width="250"
+                        MaxLength="16"
+                        ToolTip.Tip="{ext:Locale LdnPassphraseInputTooltip}"
+                        Watermark="{ext:Locale LdnPassphraseInputPublic}" />
+                    <Button
+                        Name="GenLdnPassButton"
+                        Grid.Column="1"
+                        MinWidth="90"
+                        Margin="10,0,0,0"
+                        ToolTip.Tip="{ext:Locale GenLdnPassTooltip}"
+                        Click="GenLdnPassButton_OnClick">
+                        <TextBlock HorizontalAlignment="Center"
+                                    Text="{ext:Locale GenLdnPass}" />
+                    </Button>
+                    <Button
+                        Name="ClearLdnPassButton"
+                        Grid.Column="1"
+                        MinWidth="90"
+                        Margin="10,0,0,0"
+                        ToolTip.Tip="{ext:Locale ClearLdnPassTooltip}"
+                        Click="ClearLdnPassButton_OnClick">
+                        <TextBlock HorizontalAlignment="Center"
+                                    Text="{ext:Locale ClearLdnPass}" />
+                    </Button>
+                </StackPanel>
+                <TextBlock  Margin="10,0,0,0"
+                    VerticalAlignment="Center"
+                    Name="InvalidLdnPassphraseBlock"
+                    FontStyle="Italic"
+                    IsVisible="{Binding IsInvalidLdnPassphraseVisible}"
+                    Focusable="False"
+                    Text="{ext:Locale InvalidLdnPassphrase}" />
                 <Separator Height="1" />
                 <TextBlock Classes="h1" Text="{ext:Locale SettingsTabNetworkConnection}" />
                 <CheckBox Margin="10,0,0,0" IsChecked="{Binding EnableInternetAccess}">

src/Ryujinx/UI/Views/Settings/SettingsNetworkView.axaml.cs

@@ -1,12 +1,29 @@
 using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Ryujinx.Ava.UI.ViewModels;
+using System;
 
 namespace Ryujinx.Ava.UI.Views.Settings
 {
     public partial class SettingsNetworkView : UserControl
     {
+        public SettingsViewModel ViewModel;
+
         public SettingsNetworkView()
         {
             InitializeComponent();
         }
+
+        private void GenLdnPassButton_OnClick(object sender, RoutedEventArgs e)
+        {
+            byte[] code = new byte[4];
+            new Random().NextBytes(code);
+            ViewModel.LdnPassphrase = $"Ryujinx-{BitConverter.ToUInt32(code):x8}";
+        }
+
+        private void ClearLdnPassButton_OnClick(object sender, RoutedEventArgs e)
+        {
+            ViewModel.LdnPassphrase = "";
+        }
     }
 }

src/Ryujinx/UI/Windows/MainWindow.axaml.cs

@@ -154,6 +154,36 @@ namespace Ryujinx.Ava.UI.Windows
             });
         }
 
+        private void ApplicationLibrary_LdnGameDataReceived(object sender, LdnGameDataReceivedEventArgs e)
+        {
+            Dispatcher.UIThread.Post(() =>
+            {
+                var ldnGameDataArray = e.LdnData;
+                ViewModel.LastLdnGameData = ldnGameDataArray;
+                foreach (var application in ViewModel.Applications)
+                {
+                    UpdateApplicationWithLdnData(application);
+                }
+                ViewModel.RefreshView();
+            });
+        }
+
+        private void UpdateApplicationWithLdnData(ApplicationData application)
+        {
+            if (application.ControlHolder.ByteSpan.Length > 0 && ViewModel.LastLdnGameData != null)
+            {
+                IEnumerable<LdnGameData> ldnGameData = ViewModel.LastLdnGameData.Where(game => application.ControlHolder.Value.LocalCommunicationId.Items.Contains(Convert.ToUInt64(game.TitleId, 16)));
+
+                application.PlayerCount = ldnGameData.Sum(game => game.PlayerCount);
+                application.GameCount = ldnGameData.Count();
+            }
+            else
+            {
+                application.PlayerCount = 0;
+                application.GameCount = 0;
+            }
+        }
+
         public void Application_Opened(object sender, ApplicationOpenedEventArgs args)
         {
             if (args.Application != null)
@@ -450,7 +480,20 @@ namespace Ryujinx.Ava.UI.Windows
                     .Connect()
                     .ObserveOn(SynchronizationContext.Current!)
                     .Bind(ViewModel.Applications)
+                    .OnItemAdded(UpdateApplicationWithLdnData)
                     .Subscribe();
+            ApplicationLibrary.LdnGameDataReceived += ApplicationLibrary_LdnGameDataReceived;
+
+            ConfigurationState.Instance.Multiplayer.Mode.Event += (sender, evt) =>
+            {
+                _ = Task.Run(ViewModel.ApplicationLibrary.RefreshLdn);
+            };
+
+            ConfigurationState.Instance.Multiplayer.LdnServer.Event += (sender, evt) =>
+            {
+                _ = Task.Run(ViewModel.ApplicationLibrary.RefreshLdn);
+            };
+            _ = Task.Run(ViewModel.ApplicationLibrary.RefreshLdn);
 
             ViewModel.RefreshFirmwareStatus();
 
@@ -588,13 +631,26 @@ namespace Ryujinx.Ava.UI.Windows
         {
             switch (fileType)
             {
-                case "NSP": ConfigurationState.Instance.UI.ShownFileTypes.NSP.Toggle(); break;
+                case "NSP":
-                case "PFS0": ConfigurationState.Instance.UI.ShownFileTypes.PFS0.Toggle(); break;
+                    ConfigurationState.Instance.UI.ShownFileTypes.NSP.Toggle();
-                case "XCI": ConfigurationState.Instance.UI.ShownFileTypes.XCI.Toggle(); break;
+                    break;
-                case "NCA": ConfigurationState.Instance.UI.ShownFileTypes.NCA.Toggle(); break;
+                case "PFS0":
-                case "NRO": ConfigurationState.Instance.UI.ShownFileTypes.NRO.Toggle(); break;
+                    ConfigurationState.Instance.UI.ShownFileTypes.PFS0.Toggle();
-                case "NSO": ConfigurationState.Instance.UI.ShownFileTypes.NSO.Toggle(); break;
+                    break;
-                default: throw new ArgumentOutOfRangeException(fileType);
+                case "XCI":
+                    ConfigurationState.Instance.UI.ShownFileTypes.XCI.Toggle();
+                    break;
+                case "NCA":
+                    ConfigurationState.Instance.UI.ShownFileTypes.NCA.Toggle();
+                    break;
+                case "NRO":
+                    ConfigurationState.Instance.UI.ShownFileTypes.NRO.Toggle();
+                    break;
+                case "NSO":
+                    ConfigurationState.Instance.UI.ShownFileTypes.NSO.Toggle();
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException(fileType);
             }
 
             ConfigurationState.Instance.ToFileFormat().SaveConfig(Program.ConfigurationPath);

src/Ryujinx/UI/Windows/SettingsWindow.axaml.cs

@@ -80,6 +80,7 @@ namespace Ryujinx.Ava.UI.Windows
                         NavPanel.Content = AudioPage;
                         break;
                     case "NetworkPage":
+                        NetworkPage.ViewModel = ViewModel;
                         NavPanel.Content = NetworkPage;
                         break;
                     case "LoggingPage":