/*
  *  OpenVPN -- An application to securely tunnel IP networks
  *             over a single TCP/UDP port, with support for SSL/TLS-based
  *             session authentication and key exchange,
  *             packet encryption, packet authentication, and
  *             packet compression.
  *

  *  Copyright (C) 2002-2018 OpenVPN Inc <sales@openvpn.net>
  *  Copyright (C) 2010-2018 Fox Crypto B.V. <openvpn@fox-it.com>

  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2
  *  as published by the Free Software Foundation.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *

  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

  */
 
 /**
  * @file Data Channel Cryptography OpenSSL-specific backend interface
  */
 
 #ifndef CRYPTO_OPENSSL_H_
 #define CRYPTO_OPENSSL_H_
 
 #include <openssl/evp.h>
 #include <openssl/hmac.h>
 #include <openssl/md5.h>

 #include <openssl/sha.h>

 /** Generic cipher key type %context. */
 typedef EVP_CIPHER cipher_kt_t;
 
 /** Generic message digest key type %context. */
 typedef EVP_MD md_kt_t;
 
 /** Generic cipher %context. */
 typedef EVP_CIPHER_CTX cipher_ctx_t;
 
 /** Generic message digest %context. */
 typedef EVP_MD_CTX md_ctx_t;
 
 /** Generic HMAC %context. */
 typedef HMAC_CTX hmac_ctx_t;
 

 /** Maximum length of an IV */

 #define OPENVPN_MAX_IV_LENGTH   EVP_MAX_IV_LENGTH

 
 /** Cipher is in CBC mode */

 #define OPENVPN_MODE_CBC        EVP_CIPH_CBC_MODE

 
 /** Cipher is in OFB mode */

 #define OPENVPN_MODE_OFB        EVP_CIPH_OFB_MODE

 
 /** Cipher is in CFB mode */

 #define OPENVPN_MODE_CFB        EVP_CIPH_CFB_MODE

 #ifdef HAVE_AEAD_CIPHER_MODES
 
 /** Cipher is in GCM mode */

 #define OPENVPN_MODE_GCM        EVP_CIPH_GCM_MODE

 
 #endif /* HAVE_AEAD_CIPHER_MODES */
 

 /** Cipher should encrypt */

 #define OPENVPN_OP_ENCRYPT      1

 
 /** Cipher should decrypt */

 #define OPENVPN_OP_DECRYPT      0

 #define DES_KEY_LENGTH 8

 #define MD4_DIGEST_LENGTH       16

 /**
  * Retrieve any occurred OpenSSL errors and print those errors.
  *
  * Note that this function uses the not thread-safe OpenSSL error API.
  *

  * @param flags         Flags to indicate error type and priority.

  */
 void crypto_print_openssl_errors(const unsigned int flags);
 
 /**
  * Retrieve any OpenSSL errors, then print the supplied error message.
  *
  * This is just a convenience wrapper for often occurring situations.
  *

  * @param flags         Flags to indicate error type and priority.
  * @param format        Format string to print.
  * @param format args   (optional) arguments for the format string.

  */

 #define crypto_msg(flags, ...) \
     do { \
         crypto_print_openssl_errors(nonfatal(flags)); \
         msg((flags), __VA_ARGS__); \
     } while (false)

 #endif /* CRYPTO_OPENSSL_H_ */