expose source endpoint through app session

src/SuperSocket.Connection/ConnectionBase.cs

@@ -5,6 +5,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using SuperSocket.ProtoBase;
+using SuperSocket.ProtoBase.ProxyProtocol;
 
 namespace SuperSocket.Connection
 {
@@ -30,6 +31,8 @@ public abstract class ConnectionBase : IConnection
 
         public CancellationToken ConnectionToken { get; protected set; }
 
+        public ProxyInfo ProxyInfo { get; protected set; }
+
         protected virtual void OnClosed()
         {
             IsClosed = true;

src/SuperSocket.Connection/IConnection.cs

@@ -5,6 +5,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using SuperSocket.ProtoBase;
+using SuperSocket.ProtoBase.ProxyProtocol;
 
 namespace SuperSocket.Connection
 {
@@ -35,5 +36,7 @@ public interface IConnection
         CloseReason? CloseReason { get; }
 
         CancellationToken ConnectionToken { get; }
+
+        ProxyInfo ProxyInfo { get; }
     }
 }

src/SuperSocket.Connection/PipeConnectionBase.cs

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using Microsoft.Extensions.Logging;
 using SuperSocket.ProtoBase;
+using SuperSocket.ProtoBase.ProxyProtocol;
 
 namespace SuperSocket.Connection
 {
@@ -322,6 +323,12 @@ private bool ReaderBuffer<TPackageInfo>(ref ReadOnlySequence<byte> buffer, IPipe
 
                 if (nextFilter != null)
                 {
+                    // ProxyProtocolPipelineFilter always is the first filter and its next filter is the actual first filter.
+                    if (bytesConsumedTotal == 0 && pipelineFilter is IProxyProtocolPipelineFilter proxyProtocolPipelineFilter)
+                    {
+                        ProxyInfo = proxyProtocolPipelineFilter.ProxyInfo;
+                    }
+
                     nextFilter.Context = pipelineFilter.Context; // pass through the context
                     _pipelineFilter = pipelineFilter = nextFilter;
                     filterSwitched = true;

src/SuperSocket.ProtoBase/ProxyProtocol/IProxyProtocolPipelineFilter.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Buffers;
+
+namespace SuperSocket.ProtoBase.ProxyProtocol
+{
+    public interface IProxyProtocolPipelineFilter : IPipelineFilter
+    {
+        ProxyInfo ProxyInfo { get; }
+    }
+}

src/SuperSocket.ProtoBase/ProxyProtocol/ProxyInfo.cs

@@ -25,6 +25,16 @@ public class ProxyInfo
 
         internal int AddressLength { get; set; }
 
+        public EndPoint SourceEndPoint { get; private set; }
+
+        public EndPoint DestinationEndPoint { get; private set; }
+
+        internal void Prepare()
+        {
+            SourceEndPoint = new IPEndPoint(SourceIPAddress, SourcePort);
+            DestinationEndPoint = new IPEndPoint(DestinationIPAddress, DestinationPort);
+        }
+
         public ProxyInfo()
         {
         }

src/SuperSocket.ProtoBase/ProxyProtocol/ProxyProtocolPipelineFilter.cs

@@ -3,7 +3,7 @@
 
 namespace SuperSocket.ProtoBase.ProxyProtocol
 {
-    public class ProxyProtocolPipelineFilter<TPackageInfo> : PackagePartsPipelineFilter<TPackageInfo>
+    public class ProxyProtocolPipelineFilter<TPackageInfo> : PackagePartsPipelineFilter<TPackageInfo>, IProxyProtocolPipelineFilter
     {
         private readonly IPipelineFilter<TPackageInfo> _applicationPipelineFilter;
 
@@ -29,6 +29,7 @@ protected override IPackagePartReader<TPackageInfo> GetFirstPartReader()
         public override void Reset()
         {
             // This method will be called when the proxy package handling finishes
+            ProxyInfo.Prepare();
             NextFilter = _applicationPipelineFilter;
             base.Reset();
             Context = _originalFilterContext;

src/SuperSocket.Server/AppSession.cs

@@ -55,7 +55,15 @@ IConnection IAppSession.Connection
 
         public EndPoint RemoteEndPoint
         {
-            get { return _connection?.RemoteEndPoint; }
+            get
+            {
+                var connection = _connection;
+
+                if (connection == null)
+                    return null;
+
+                return connection.ProxyInfo?.SourceEndPoint ?? connection.RemoteEndPoint;
+            }
         }
 
         public EndPoint LocalEndPoint