Enable TCP_NODELAY

Dalamud/Dalamud.cs

@@ -46,6 +46,8 @@ namespace Dalamud {
 
         public readonly DalamudConfiguration Configuration;
 
+        internal readonly WinSockHandlers WinSock2;
+
         public Dalamud(DalamudStartInfo info) {
             this.StartInfo = info;
             this.Configuration = DalamudConfiguration.Load(info.ConfigurationPath);
@@ -75,7 +77,9 @@ namespace Dalamud {
             this.PluginManager = new PluginManager(this, info.PluginDirectory, info.DefaultPluginDirectory);
 
             this.IconReplacer = new IconReplacer(this, this.sigScanner);
-            
+
+            this.WinSock2 = new WinSockHandlers();
+
             try {
                 this.PluginManager.LoadPlugins();
             } catch (Exception ex) {
@@ -109,6 +113,8 @@ namespace Dalamud {
 
             this.unloadSignal.Dispose();
 
+            this.WinSock2.Dispose();
+
             if (this.Configuration.ComboPresets != CustomComboPreset.None)
                 this.IconReplacer.Dispose();
         }

Dalamud/Game/Network/WinSockHandlers.cs

@@ -0,0 +1,55 @@
+using Dalamud.Hooking;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Dalamud.Game
+{
+    internal sealed class WinSockHandlers : IDisposable
+    {
+        [UnmanagedFunctionPointer(CallingConvention.Winapi)]
+        private delegate IntPtr SocketDelegate(int af, int type, int protocol);
+        private Hook<SocketDelegate> ws2SocketHook;
+
+        [DllImport("ws2_32.dll", CallingConvention = CallingConvention.Winapi)]
+        private static extern int setsockopt(IntPtr socket, SocketOptionLevel level, SocketOptionName optName, ref IntPtr optVal, int optLen);
+
+        public WinSockHandlers() {
+            ws2SocketHook = Hook<SocketDelegate>.FromSymbol("ws2_32.dll", "socket", new SocketDelegate(OnSocket));
+            ws2SocketHook.Enable();
+        }
+
+        private IntPtr OnSocket(int af, int type, int protocol)
+        {
+            var socket = ws2SocketHook.Original(af, type, protocol);
+
+            // IPPROTO_TCP
+            if (type == 1)
+            {
+                // INVALID_SOCKET 
+                if (socket != new IntPtr(-1))
+                {
+                    // In case you're not aware of it: (albeit you should)
+                    // https://linux.die.net/man/7/tcp
+                    // https://assets.extrahop.com/whitepapers/TCP-Optimization-Guide-by-ExtraHop.pdf
+                    var value = new IntPtr(1);
+                    setsockopt(socket, SocketOptionLevel.Tcp, SocketOptionName.NoDelay, ref value, 4);
+
+                    // Enable tcp_quickack option. This option is undocumented in MSDN but it is supported in Windows 7 and onwards.
+                    value = new IntPtr(1);
+                    setsockopt(socket, SocketOptionLevel.Tcp, (SocketOptionName)12, ref value, 4);
+                }
+            }
+
+            return socket;
+        }
+
+        public void Dispose() {
+            ws2SocketHook.Dispose();
+        }
+    }
+}