Initial commit

Proxies/SOCKS4ProxyProtocol.cs

@@ -0,0 +1,82 @@
+/*
+ * Secucore
+ * 
+ * Copyright (C) 2023 Trevor Hall
+ * All rights reserved.
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.
+ * 
+ */
+
+using System.Collections.Generic;
+using System.Net;
+using System.Threading.Tasks;
+using System;
+
+namespace SecuCore.Proxies
+{
+    public class SOCKS4ProxyProtocol : IProxyProtocol
+    {
+        public static async Task<bool> ConnectAsync(Sockets.TCPNetworkStream tcpns, string remoteHost, int remotePort, string proxyUsername, string proxyPassword)
+        {
+            byte[] conp = Socks4ConnectPacket(remoteHost, remotePort);
+            await tcpns.WriteAsync(conp, 0, conp.Length).ConfigureAwait(false);
+            byte[] readb = new byte[64];
+            int len = await tcpns.ReadAsync(readb, 0, readb.Length).ConfigureAwait(false);
+            if (len <= 0) return false;
+
+            if (readb[0] == 0x04)
+            {
+                if (readb[1] == 0x5A)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        public static byte[] Socks4ConnectPacket(string host, int port)
+        {
+            List<byte> connectionPacket = new();
+            {
+                var withBlock = connectionPacket;
+                // Write packet feader
+                withBlock.Add(4); // socks version 4
+                withBlock.Add(1); // TCP Stream Connection
+
+                // Write port, network order
+                withBlock.AddRange(PortToBytes(port));
+
+                // Write address, network order
+                IPAddress dest = IPAddress.Parse(host);
+                byte[] ipb = dest.GetAddressBytes();
+                Array.Reverse(ipb);
+                withBlock.AddRange(ipb);
+                withBlock.Add(0);
+            }
+            return connectionPacket.ToArray();
+        }
+
+        private static byte[] PortToBytes(int port)
+        {
+            ushort ps = (ushort)port;
+            byte[] pb = BitConverter.GetBytes(ps);
+
+            // network order bytes
+            byte[] nb = new byte[2];
+
+            if (BitConverter.IsLittleEndian)
+            {
+                nb[0] = pb[1];
+                nb[1] = pb[0];
+            }
+            else
+            {
+                nb[0] = pb[0];
+                nb[1] = pb[1];
+            }
+            return nb;
+        }
+    }
+}