get original ip from X-Forwarded-For

EVCB_OCPP.WSServer/Service/WsService/WebsocketService.cs

@@ -1,6 +1,7 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using System.Data.Entity.Core.Common.EntitySql;
 using System.Net;
 using System.Net.Http;
 using System.Net.WebSockets;
@@ -75,9 +76,33 @@ public class WebsocketService<T> where T : WsSession
 
         try
         {
-            var ipaddress = context.Connection.RemoteIpAddress;
-            var port = context.Connection.RemotePort;
-            data.Endpoint = new IPEndPoint(ipaddress, port);
+            var proxyPassClientIp = context.Request.Headers["X-Forwarded-For"];
+            foreach (var infoString in proxyPassClientIp)
+            {
+                foreach (var testIp in infoString.Split(','))
+                {
+                    logger.LogDebug("X-Forwarded-For {ip}", testIp);
+                    if (IPEndPoint.TryParse(testIp, out var parseResult) &&
+                        (parseResult.AddressFamily is System.Net.Sockets.AddressFamily.InterNetwork or System.Net.Sockets.AddressFamily.InterNetworkV6)
+                        )
+                    {
+                        data.Endpoint = parseResult;
+                        break;
+                    }
+                }
+
+                if (data.Endpoint != null)
+                {
+                    break;
+                }
+            }
+
+            if (data.Endpoint is null)
+            {
+                var ipaddress = context.Connection.RemoteIpAddress;
+                var port = context.Connection.RemotePort;
+                data.Endpoint = new IPEndPoint(ipaddress, port);
+            }
         }
         catch
         {