Refine encryption

introduce a constructor to store inner method name

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

shadowsocks-csharp/Encryption/EncryptorBase.cs

@@ -4,17 +4,27 @@ namespace Shadowsocks.Encryption
 {
     public struct EncryptorInfo
     {
-        public string name;
-        public int key_size;
-        public int iv_size;
-        public int type;
+        public int KeySize;
+        public int IvSize;
+        public int Type;
+        public string InnerLibName;
+
+        // For those who make use of internal crypto method name
+        // e.g. mbed TLS
+        public EncryptorInfo(string innerLibName, int keySize, int ivSize, int type)
+        {
+            this.KeySize = keySize;
+            this.IvSize = ivSize;
+            this.Type = type;
+            this.InnerLibName = innerLibName;
+        }
 
-        public EncryptorInfo(string name, int key_size, int iv_size, int type)
+        public EncryptorInfo(int keySize, int ivSize, int type)
         {
-            this.name = name;
-            this.key_size = key_size;
-            this.iv_size = iv_size;
-            this.type = type;
+            this.KeySize = keySize;
+            this.IvSize = ivSize;
+            this.Type = type;
+            this.InnerLibName = string.Empty;
         }
     }
 

shadowsocks-csharp/Encryption/IVEncryptor.cs

@@ -25,9 +25,9 @@ namespace Shadowsocks.Encryption
         protected bool _encryptIVSent;
         protected string _method;
         protected int _cipher;
-        // cipher name in MbedTLS, useless when using LibSodium
-        protected string _cipherMbedName;
-        protected EncryptorInfo _cipherInfo;
+        // internal name in the crypto library
+        protected string _innerLibName;
+        protected EncryptorInfo CipherInfo;
         protected byte[] _key;
         protected int keyLen;
         protected int ivLen;
@@ -46,15 +46,15 @@ namespace Shadowsocks.Encryption
             _method = method;
             string k = method + ":" + password;
             ciphers = getCiphers();
-            _cipherInfo = ciphers[_method];
-            _cipherMbedName = _cipherInfo.name;
-            _cipher = _cipherInfo.type;
+            CipherInfo = ciphers[_method];
+            _innerLibName = CipherInfo.InnerLibName;
+            _cipher = CipherInfo.Type;
             if (_cipher == 0)
             {
                 throw new Exception("method not found");
             }
-            keyLen = _cipherInfo.key_size;
-            ivLen = _cipherInfo.iv_size;
+            keyLen = CipherInfo.KeySize;
+            ivLen = CipherInfo.IvSize;
             _key = CachedKeys.GetOrAdd(k, (nk) =>
             {
                 byte[] passbuf = Encoding.UTF8.GetBytes(password);

shadowsocks-csharp/Encryption/MbedTLSEncryptor.cs

@@ -70,7 +70,7 @@ namespace Shadowsocks.Encryption
                 realkey = _key;
             }
             MbedTLS.cipher_init(ctx);
-            if (MbedTLS.cipher_setup( ctx, MbedTLS.cipher_info_from_string( _cipherMbedName ) ) != 0 )
+            if (MbedTLS.cipher_setup( ctx, MbedTLS.cipher_info_from_string( _innerLibName ) ) != 0 )
                 throw new Exception("Cannot initialize mbed TLS cipher context");
             /*
              * MbedTLS takes key length by bit

shadowsocks-csharp/Encryption/SodiumEncryptor.cs

@@ -25,9 +25,9 @@ namespace Shadowsocks.Encryption
         }
 
         private static Dictionary<string, EncryptorInfo> _ciphers = new Dictionary<string, EncryptorInfo> {
-            { "salsa20", new EncryptorInfo("salsa20", 32, 8, CIPHER_SALSA20) },
-            { "chacha20", new EncryptorInfo("chacha20", 32, 8, CIPHER_CHACHA20) },
-            { "chacha20-ietf", new EncryptorInfo("chacha20-ietf", 32, 12, CIPHER_CHACHA20_IETF) }
+            { "salsa20", new EncryptorInfo(32, 8, CIPHER_SALSA20) },
+            { "chacha20", new EncryptorInfo(32, 8, CIPHER_CHACHA20) },
+            { "chacha20-ietf", new EncryptorInfo(32, 12, CIPHER_CHACHA20_IETF) }
         };
 
         protected override Dictionary<string, EncryptorInfo> getCiphers()