less hard coding of cipher mode in libgcrypt backend

src/libgcrypt.c

@@ -524,16 +524,14 @@ _libssh2_cipher_init(_libssh2_cipher_ctx * h,
                      _libssh2_cipher_type(algo),
                      unsigned char *iv, unsigned char *secret, int encrypt)
 {
-    int mode = 0, ret;
-    int keylen = gcry_cipher_get_algo_keylen(algo);
+    int ret;
+    int cipher = _libssh2_gcry_cipher (algo);
+    int mode = _libssh2_gcry_mode (algo);
+    int keylen = gcry_cipher_get_algo_keylen(cipher);
 
     (void) encrypt;
 
-    if (algo != GCRY_CIPHER_ARCFOUR) {
-        mode = GCRY_CIPHER_MODE_CBC;
-    }
-
-    ret = gcry_cipher_open(h, algo, mode, 0);
+    ret = gcry_cipher_open(h, cipher, mode, 0);
     if (ret) {
         return -1;
     }
@@ -544,8 +542,8 @@ _libssh2_cipher_init(_libssh2_cipher_ctx * h,
         return -1;
     }
 
-    if (algo != GCRY_CIPHER_ARCFOUR) {
-        int blklen = gcry_cipher_get_algo_blklen(algo);
+    if (mode != GCRY_CIPHER_MODE_STREAM) {
+        int blklen = gcry_cipher_get_algo_blklen(cipher);
         ret = gcry_cipher_setiv(*h, iv, blklen);
         if (ret) {
             gcry_cipher_close(*h);
@@ -561,8 +559,10 @@ _libssh2_cipher_crypt(_libssh2_cipher_ctx * ctx,
                       _libssh2_cipher_type(algo),
                       int encrypt, unsigned char *block)
 {
-    size_t blklen = gcry_cipher_get_algo_blklen(algo);
+    int cipher = _libssh2_gcry_cipher (algo);
+    size_t blklen = gcry_cipher_get_algo_blklen(cipher);
     int ret;
+
     if (blklen == 1) {
 /* Hack for arcfour. */
         blklen = 8;

src/libgcrypt.h

@@ -1,5 +1,6 @@
-/* Copyright (C) 2006, 2007, The Written Word, Inc.
- * Copyright (C) 2008, Simon Josefsson
+/*
+ * Copyright (C) 2008, 2009 Simon Josefsson
+ * Copyright (C) 2006, 2007, The Written Word, Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms,
@@ -155,13 +156,24 @@ int _libssh2_dsa_sha1_sign(libssh2_dsa_ctx * dsactx,
 #define _libssh2_cipher_type(name) int name
 #define _libssh2_cipher_ctx gcry_cipher_hd_t
 
-#define _libssh2_cipher_aes256 GCRY_CIPHER_AES256
-#define _libssh2_cipher_aes192 GCRY_CIPHER_AES192
-#define _libssh2_cipher_aes128 GCRY_CIPHER_AES128
-#define _libssh2_cipher_blowfish GCRY_CIPHER_BLOWFISH
-#define _libssh2_cipher_arcfour GCRY_CIPHER_ARCFOUR
-#define _libssh2_cipher_cast5 GCRY_CIPHER_CAST5
-#define _libssh2_cipher_3des GCRY_CIPHER_3DES
+#define _libssh2_gcry_ciphermode(c,m) ((c << 8) | m)
+#define _libssh2_gcry_cipher(c) (c >> 8)
+#define _libssh2_gcry_mode(m) (m & 0xFF)
+
+#define _libssh2_cipher_aes256			\
+  _libssh2_gcry_ciphermode(GCRY_CIPHER_AES256, GCRY_CIPHER_MODE_CBC)
+#define _libssh2_cipher_aes192			\
+  _libssh2_gcry_ciphermode(GCRY_CIPHER_AES192, GCRY_CIPHER_MODE_CBC)
+#define _libssh2_cipher_aes128			\
+  _libssh2_gcry_ciphermode(GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_CBC)
+#define _libssh2_cipher_blowfish		\
+  _libssh2_gcry_ciphermode(GCRY_CIPHER_BLOWFISH, GCRY_CIPHER_MODE_CBC)
+#define _libssh2_cipher_arcfour			\
+  _libssh2_gcry_ciphermode(GCRY_CIPHER_ARCFOUR, GCRY_CIPHER_MODE_STREAM)
+#define _libssh2_cipher_cast5			\
+  _libssh2_gcry_ciphermode(GCRY_CIPHER_CAST5, GCRY_CIPHER_MODE_CBC)
+#define _libssh2_cipher_3des			\
+  _libssh2_gcry_ciphermode(GCRY_CIPHER_3DES, GCRY_CIPHER_MODE_CBC)
 
 int _libssh2_cipher_init(_libssh2_cipher_ctx * h,
                          _libssh2_cipher_type(algo),