IPv6 fix

Author: honfika

src/Titanium.Web.Proxy/Network/Tcp/TcpConnectionFactory.cs

@@ -71,7 +71,6 @@ internal string GetConnectionCacheKey(string remoteHostName, int remotePort,
             cacheKeyBuilder.Append(externalProxy != null ? $"{externalProxy.GetCacheKey()}-" : string.Empty);
 
             return cacheKeyBuilder.ToString();
-
         }
 
         /// <summary>
@@ -280,20 +279,6 @@ private async Task<TcpServerConnection> createServerConnection(string remoteHost
             retry:
             try
             {
-                tcpClient = new TcpClient(upStreamEndPoint)
-                {
-                    NoDelay = proxyServer.NoDelay,
-                    ReceiveTimeout = proxyServer.ConnectionTimeOutSeconds * 1000,
-                    SendTimeout = proxyServer.ConnectionTimeOutSeconds * 1000,
-                    LingerState = new LingerOption(true, proxyServer.TcpTimeWaitSeconds)
-                };
-
-                // linux has a bug with socket reuse in .net core.
-                if (proxyServer.ReuseSocket && RunTime.IsWindows)
-                {
-                    tcpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
-                }
-
                 var hostname = useUpstreamProxy ? externalProxy.HostName : remoteHostName;
                 var port = useUpstreamProxy ? externalProxy.Port : remotePort;
 
@@ -312,6 +297,27 @@ private async Task<TcpServerConnection> createServerConnection(string remoteHost
                 {
                     try
                     {
+                        var ipAddress = ipAddresses[i];
+                        if (upStreamEndPoint == null)
+                        {
+                            tcpClient = new TcpClient(ipAddress.AddressFamily);
+                        }
+                        else
+                        {
+                            tcpClient = new TcpClient(upStreamEndPoint);
+                        }
+
+                        tcpClient.NoDelay = proxyServer.NoDelay;
+                        tcpClient.ReceiveTimeout = proxyServer.ConnectionTimeOutSeconds * 1000;
+                        tcpClient.SendTimeout = proxyServer.ConnectionTimeOutSeconds * 1000;
+                        tcpClient.LingerState = new LingerOption(true, proxyServer.TcpTimeWaitSeconds);
+
+                        // linux has a bug with socket reuse in .net core.
+                        if (proxyServer.ReuseSocket && RunTime.IsWindows)
+                        {
+                            tcpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
+                        }
+
                         await tcpClient.ConnectAsync(ipAddresses[i], port);
                         break;
                     }

src/Titanium.Web.Proxy/ProxyServer.cs

@@ -268,7 +268,7 @@ public ProxyServer(string rootCertificateName, string rootCertificateIssuerName,
         ///     Local adapter/NIC endpoint where proxy makes request via.
         ///     Defaults via any IP addresses of this machine.
         /// </summary>
-        public IPEndPoint UpStreamEndPoint { get; set; } = new IPEndPoint(IPAddress.Any, 0);
+        public IPEndPoint UpStreamEndPoint { get; set; }
 
         /// <summary>
         ///     A list of IpAddress and port this proxy is listening to.