Make port reusable between sessions

p2pconn/Form1.cs

@@ -13,6 +13,7 @@
 using UdtSharp;
 using System.IO;
 using p2p.StunServer;
+using p2p.p2p;
 
 namespace p2pconn
 {
@@ -78,10 +79,7 @@ private void CheckDataGridView()
 
         private void GetEndPoint()
         {
-            int newPort = r.Next(49152, 65535);
-            socket.Bind(new IPEndPoint(IPAddress.Any, newPort));
-
-            P2pEndPoint p2pEndPoint = GetExternalEndPoint(socket);
+            P2pEndPoint p2pEndPoint = GetP2pEndPoint();
 
             if (p2pEndPoint == null)
                 return;
@@ -93,6 +91,19 @@ private void GetEndPoint()
             string[] words = localendpoint.Split(':');
             // txtLocalHost.Text = Functions.Base64Encode(GetPhysicalIPAdress() + ":" + words[1]);
             txtLocalHost.Text = GetPhysicalIPAdress() + ":" + words[1];
+
+            P2pEndPoint GetP2pEndPoint()
+            {
+                string storedPort = RegistryFuncs.GetFromRegistry(P2PKeys.LastPort);
+                int newPort = r.Next(49152, 65535);
+                if (!string.IsNullOrEmpty(storedPort))
+                    newPort = Convert.ToInt32(storedPort);
+                socket.Bind(new IPEndPoint(IPAddress.Any, newPort));
+                P2pEndPoint tmpEndPoint = GetExternalEndPoint(socket);
+                if (tmpEndPoint != null)
+                    RegistryFuncs.SetToRegistry(P2PKeys.LastPort, newPort.ToString());
+                return tmpEndPoint;
+            }
         }
 
         private string GetPhysicalIPAdress()

p2pconn/RegistryFuncs.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace p2p
+{
+    using Microsoft.Win32;
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Text;
+    using System.Threading.Tasks;
+
+    namespace p2p
+    {
+        public enum P2PKeys
+        {
+            LastIp,
+            LastPort,
+            LastExternalIP,
+            LastExternalPort,
+        }
+
+        public static class RegistryFuncs
+        {
+            public const string P2pPath = @"HKEY_CURRENT_USER\Software\P2pRemoteDesktop\";
+            public static string GetFromRegistry(P2PKeys key)
+            {
+                string keyValue = (string)Registry.GetValue(P2pPath, key.ToString(), null);
+                return keyValue;
+            }
+            public static void SetToRegistry(P2PKeys key, string value)
+            {
+                Registry.SetValue(P2pPath, key.ToString(), value);
+            }
+        }
+    }
+}

p2pconn/p2pconn.csproj

@@ -106,6 +106,7 @@
       <DependentUpon>Form1.cs</DependentUpon>
     </Compile>
     <Compile Include="Functions.cs" />
+    <Compile Include="RegistryFuncs.cs" />
     <Compile Include="StreamingDesktop\InputControl.cs" />
     <Compile Include="StreamingDesktop\pDesktop.cs">
       <SubType>Form</SubType>