Merge pull request #12 from canbingzt/master

refactoring encryptor

shadowsocks-csharp/Encrypt/EncryptorBase.cs

@@ -0,0 +1,29 @@
+using System.Security.Cryptography;
+using System.Text;
+
+namespace shadowsocks_csharp.Encrypt
+{
+    public abstract class EncryptorBase
+        : IEncryptor
+    {
+        protected EncryptorBase(string method, string password)
+        {
+            Method = method;
+            Password = password;
+        }
+
+        protected string Method;
+        protected string Password;
+
+        protected byte[] GetPasswordHash()
+        {
+            byte[] inputBytes = Encoding.UTF8.GetBytes(Password);
+            byte[] hash = MD5.Create().ComputeHash(inputBytes);
+            return hash;
+        }
+
+        public abstract byte[] Encrypt(byte[] buf, int length);
+
+        public abstract byte[] Decrypt(byte[] buf, int length);
+    }
+}

shadowsocks-csharp/Encrypt/EncryptorFactory.cs

@@ -0,0 +1,21 @@
+
+namespace shadowsocks_csharp.Encrypt
+{
+    public static class EncryptorFactory
+    {
+        public static IEncryptor GetEncryptor(string method, string password)
+        {
+            if (string.IsNullOrEmpty(method) || method.ToLowerInvariant() == "table")
+            {
+                return new TableEncryptor(method, password);
+            }
+
+            if (method.ToLowerInvariant() == "rc4")
+            {
+                return new Rc4Encryptor(method, password);
+            }
+
+            return new OpensslEncryptor(method, password);
+        }
+    }
+}

shadowsocks-csharp/Encrypt/IEncryptor.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace shadowsocks_csharp.Encrypt
+{
+    public interface IEncryptor
+    {
+        byte[] Encrypt(byte[] buf, int length);
+        byte[] Decrypt(byte[] buf, int length);
+    }
+}

shadowsocks-csharp/Encrypt/OpensslEncryptor.cs

@@ -0,0 +1,156 @@
+using OpenSSL.Core;
+using OpenSSL.Crypto;
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace shadowsocks_csharp.Encrypt
+{
+    public class OpensslEncryptor
+        : EncryptorBase, IDisposable
+    {
+        public OpensslEncryptor(string method, string password)
+            : base(method, password)
+        {
+            InitKey(Method, Password);
+        }
+
+        public override byte[] Encrypt(byte[] buf, int length)
+        {
+            if (_encryptCtx == IntPtr.Zero)
+            {
+                int ivLen = _cipher.IVLength;
+                byte[] iv = new byte[ivLen];
+                Native.RAND_bytes(iv, iv.Length);
+                InitCipher(ref _encryptCtx, iv, true);
+                int outLen = length + _cipher.BlockSize;
+                byte[] cipherText = new byte[outLen];
+                Native.EVP_CipherUpdate(_encryptCtx, cipherText, out outLen, buf, length);
+                byte[] result = new byte[outLen + ivLen];
+                Buffer.BlockCopy(iv, 0, result, 0, ivLen);
+                Buffer.BlockCopy(cipherText, 0, result, ivLen, outLen);
+                return result;
+            }
+            else
+            {
+                int outLen = length + _cipher.BlockSize;
+                byte[] cipherText = new byte[outLen];
+                Native.EVP_CipherUpdate(_encryptCtx, cipherText, out outLen, buf, length);
+                byte[] result = new byte[outLen];
+                Buffer.BlockCopy(cipherText, 0, result, 0, outLen);
+                return result;
+            }
+        }
+
+        public override byte[] Decrypt(byte[] buf, int length)
+        {
+            if (_decryptCtx == IntPtr.Zero)
+            {
+                int ivLen = _cipher.IVLength;
+                byte[] iv = new byte[ivLen];
+                Buffer.BlockCopy(buf, 0, iv, 0, ivLen);
+                InitCipher(ref _decryptCtx, iv, false);
+                int outLen = length + _cipher.BlockSize;
+                outLen -= ivLen;
+                byte[] cipherText = new byte[outLen];
+                byte[] subset = new byte[length - ivLen];
+                Buffer.BlockCopy(buf, ivLen, subset, 0, length - ivLen);
+                Native.EVP_CipherUpdate(_decryptCtx, cipherText, out outLen, subset, length - ivLen);
+                byte[] result = new byte[outLen];
+                Buffer.BlockCopy(cipherText, 0, result, 0, outLen);
+                return result;
+            }
+            else
+            {
+                int outLen = length + _cipher.BlockSize;
+                byte[] cipherText = new byte[outLen];
+                Native.EVP_CipherUpdate(_decryptCtx, cipherText, out outLen, buf, length);
+                byte[] result = new byte[outLen];
+                Buffer.BlockCopy(cipherText, 0, result, 0, outLen);
+                return result;
+            }
+        }
+
+        private static readonly Dictionary<string, byte[]> CachedKeys = new Dictionary<string, byte[]>();
+        private static readonly Dictionary<string, Cipher> CachedCiphers = new Dictionary<string, Cipher>();
+        private byte[] _key;
+        private Cipher _cipher;
+        private IntPtr _encryptCtx;
+        private IntPtr _decryptCtx;
+
+        private void InitKey(string password, string method)
+        {
+            string k = method + ":" + password;
+            if (CachedKeys.ContainsKey(k))
+            {
+                _key = CachedKeys[k];
+                _cipher = CachedCiphers[k];
+                return;
+            }
+            _cipher = Cipher.CreateByName(method);
+            if (_cipher == null)
+            {
+                throw new NullReferenceException();
+            }
+            byte[] passbuf = Encoding.UTF8.GetBytes(password);
+            _key = new byte[_cipher.KeyLength];
+            byte[] iv = new byte[_cipher.IVLength];
+            Native.EVP_BytesToKey(_cipher.Handle, MessageDigest.MD5.Handle, null, passbuf, passbuf.Length, 1, _key, iv);
+            CachedKeys[k] = _key;
+            CachedCiphers[k] = _cipher;
+        }
+
+        private void InitCipher(ref IntPtr ctx, byte[] iv, bool isCipher)
+        {
+            ctx = Native.OPENSSL_malloc(Marshal.SizeOf(typeof(CipherContext.EVP_CIPHER_CTX)));
+            int enc = isCipher ? 1 : 0;
+            Native.EVP_CIPHER_CTX_init(ctx);
+            Native.ExpectSuccess(Native.EVP_CipherInit_ex(ctx, _cipher.Handle, IntPtr.Zero, null, null, enc));
+            Native.ExpectSuccess(Native.EVP_CIPHER_CTX_set_key_length(ctx, _key.Length));
+            Native.ExpectSuccess(Native.EVP_CIPHER_CTX_set_padding(ctx, 1));
+            Native.ExpectSuccess(Native.EVP_CipherInit_ex(ctx, _cipher.Handle, IntPtr.Zero, _key, iv, enc));
+        }
+
+        #region IDisposable
+        private bool _disposed;
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        ~OpensslEncryptor()
+        {
+            Dispose(false);
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!_disposed)
+            {
+                if (disposing)
+                {
+
+                }
+
+                if (_encryptCtx != IntPtr.Zero)
+                {
+                    Native.EVP_CIPHER_CTX_cleanup(_encryptCtx);
+                    Native.OPENSSL_free(_encryptCtx);
+                    _encryptCtx = IntPtr.Zero;
+                }
+                if (_decryptCtx != IntPtr.Zero)
+                {
+                    Native.EVP_CIPHER_CTX_cleanup(_decryptCtx);
+                    Native.OPENSSL_free(_decryptCtx);
+                    _decryptCtx = IntPtr.Zero;
+                }
+
+                _disposed = true;
+            }
+        }
+        #endregion
+    }
+}

shadowsocks-csharp/Encrypt/RC4Encryptor.cs

@@ -0,0 +1,81 @@
+
+namespace shadowsocks_csharp.Encrypt
+{
+    public class Rc4Encryptor
+        : EncryptorBase
+    {
+        public Rc4Encryptor(string method, string password)
+            : base(method, password)
+        {
+            byte[] hash = GetPasswordHash();
+            _encryptTable = EncryptInitalize(hash);
+            _decryptTable = EncryptInitalize(hash);
+        }
+
+        public override byte[] Encrypt(byte[] buf, int length)
+        {
+            return EncryptOutput(enc_ctx, _encryptTable, buf, length);
+        }
+
+        public override byte[] Decrypt(byte[] buf, int length)
+        {
+            return EncryptOutput(dec_ctx, _decryptTable, buf, length);
+        }
+
+        private readonly byte[] _encryptTable = new byte[256];
+        private readonly byte[] _decryptTable = new byte[256];
+
+        private Context enc_ctx = new Context();
+        private Context dec_ctx = new Context();
+
+        private byte[] EncryptOutput(Context ctx, byte[] s, byte[] data, int length)
+        {
+            byte[] result = new byte[length];
+            for (int n = 0; n < length; n++)
+            {
+                byte b = data[n];
+
+                ctx.Index1 = (ctx.Index1 + 1) & 255;
+                ctx.Index2 = (ctx.Index2 + s[ctx.Index1]) & 255;
+
+                Swap(s, ctx.Index1, ctx.Index2);
+
+                result[n] = (byte)(b ^ s[(s[ctx.Index1] + s[ctx.Index2]) & 255]);
+            }
+            return result;
+        }
+
+        private byte[] EncryptInitalize(byte[] key)
+        {
+            var s = new byte[256];
+
+            for (int i = 0; i < 256; i++)
+            {
+                s[i] = (byte)i;
+            }
+
+            for (int i = 0, j = 0; i < 256; i++)
+            {
+                j = (j + key[i % key.Length] + s[i]) & 255;
+
+                Swap(s, i, j);
+            }
+
+            return s;
+        }
+
+        private static void Swap(byte[] s, int i, int j)
+        {
+            byte c = s[i];
+
+            s[i] = s[j];
+            s[j] = c;
+        }
+
+        class Context
+        {
+            public int Index1;
+            public int Index2;
+        }
+    }
+}

shadowsocks-csharp/Encrypt/TableEncryptor.cs

@@ -0,0 +1,96 @@
+using System;
+
+namespace shadowsocks_csharp.Encrypt
+{
+    public class TableEncryptor
+        : EncryptorBase
+    {
+        public TableEncryptor(string method, string password)
+            : base(method, password)
+        {
+            byte[] hash = GetPasswordHash();
+            // TODO endian
+            ulong a = BitConverter.ToUInt64(hash, 0);
+            for (int i = 0; i < 256; i++)
+            {
+                _encryptTable[i] = (byte)i;
+            }
+            for (int i = 1; i < 1024; i++)
+            {
+                _encryptTable = MergeSort(_encryptTable, a, i);
+            }
+            for (int i = 0; i < 256; i++)
+            {
+                _decryptTable[_encryptTable[i]] = (byte)i;
+            }
+        }
+
+        public override byte[] Encrypt(byte[] buf, int length)
+        {
+            byte[] result = new byte[length];
+            for (int i = 0; i < length; i++)
+            {
+                result[i] = _encryptTable[buf[i]];
+            }
+            return result;
+        }
+
+        public override byte[] Decrypt(byte[] buf, int length)
+        {
+            byte[] result = new byte[length];
+            for (int i = 0; i < length; i++)
+            {
+                result[i] = _decryptTable[buf[i]];
+            }
+            return result;
+        }
+
+        private readonly byte[] _encryptTable = new byte[256];
+        private readonly byte[] _decryptTable = new byte[256];
+
+        private static long Compare(byte x, byte y, ulong a, int i)
+        {
+            return (long)(a % (ulong)(x + i)) - (long)(a % (ulong)(y + i));
+        }
+
+        private byte[] MergeSort(byte[] array, ulong a, int j)
+        {
+            if (array.Length == 1)
+            {
+                return array;
+            }
+            int middle = array.Length / 2;
+            byte[] left = new byte[middle];
+            for (int i = 0; i < middle; i++)
+            {
+                left[i] = array[i];
+            }
+            byte[] right = new byte[array.Length - middle];
+            for (int i = 0; i < array.Length - middle; i++)
+            {
+                right[i] = array[i + middle];
+            }
+            left = MergeSort(left, a, j);
+            right = MergeSort(right, a, j);
+
+            int leftptr = 0;
+            int rightptr = 0;
+
+            byte[] sorted = new byte[array.Length];
+            for (int k = 0; k < array.Length; k++)
+            {
+                if (rightptr == right.Length || ((leftptr < left.Length) && (Compare(left[leftptr], right[rightptr], a, j) <= 0)))
+                {
+                    sorted[k] = left[leftptr];
+                    leftptr++;
+                }
+                else if (leftptr == left.Length || ((rightptr < right.Length) && (Compare(right[rightptr], left[leftptr], a, j)) <= 0))
+                {
+                    sorted[k] = right[rightptr];
+                    rightptr++;
+                }
+            }
+            return sorted;
+        }
+    }
+}

shadowsocks-csharp/Local.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Text;
 using System.Net.Sockets;
 using System.Net;
+using shadowsocks_csharp.Encrypt;
 
 namespace shadowsocks_csharp
 {
@@ -11,12 +12,12 @@ namespace shadowsocks_csharp
     class Local
     {
         private Config config;
-        private Encryptor encryptor;
+        //private Encryptor encryptor;
         Socket listener;
         public Local(Config config)
         {
             this.config = config;
-            this.encryptor = new Encryptor(config.method, config.password);
+            //this.encryptor = new Encryptor(config.method, config.password);
         }
 
         public void Start()
@@ -53,6 +54,11 @@ namespace shadowsocks_csharp
 
                 // Get the socket that handles the client request.
                 Socket listener = (Socket)ar.AsyncState;
+                if (!listener.Connected)
+                {
+                    return;
+                }
+
                 listener.BeginAccept(
                     new AsyncCallback(AcceptCallback),
                     listener);
@@ -62,11 +68,15 @@ namespace shadowsocks_csharp
                 // Create the state object.
                 Handler handler = new Handler();
                 handler.connection = conn;
-                if (encryptor.method == "table") {
-                    handler.encryptor = encryptor;
-                } else {
-                    handler.encryptor = new Encryptor(config.method, config.password);
-                }
+                //if (encryptor.method == "table")
+                //{
+                //    handler.encryptor = encryptor;
+                //}
+                //else
+                //{
+                //    handler.encryptor = new Encryptor(config.method, config.password);
+                //}
+                handler.encryptor = EncryptorFactory.GetEncryptor(config.method, config.password);
                 handler.config = config;
 
                 handler.Start();
@@ -83,7 +93,8 @@ namespace shadowsocks_csharp
 
     class Handler
     {
-        public Encryptor encryptor;
+        //public Encryptor encryptor;
+        public IEncryptor encryptor;
         public Config config;
         // Client  socket.
         public Socket remote;
@@ -140,7 +151,7 @@ namespace shadowsocks_csharp
                     Console.WriteLine(e.ToString());
                 }
             }
-            encryptor.Dispose();
+            //encryptor.Dispose();
         }
 
         private void connectCallback(IAsyncResult ar)

shadowsocks-csharp/shadowsocks-csharp.csproj

@@ -46,6 +46,7 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <Prefer32Bit>false</Prefer32Bit>
+    <UseVSHostingProcess>true</UseVSHostingProcess>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -83,6 +84,12 @@
     <Reference Include="System.Windows.Forms" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Encrypt\EncryptorBase.cs" />
+    <Compile Include="Encrypt\EncryptorFactory.cs" />
+    <Compile Include="Encrypt\OpensslEncryptor.cs" />
+    <Compile Include="Encrypt\Rc4Encryptor.cs" />
+    <Compile Include="Encrypt\TableEncryptor.cs" />
+    <Compile Include="Encrypt\IEncryptor.cs" />
     <Compile Include="RC4.cs" />
     <Compile Include="Config.cs" />
     <Compile Include="Encryptor.cs" />