/*
  *  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) 2002-2017 OpenVPN Technologies, Inc. <sales@openvpn.net>
  *  Copyright (C) 2010-2017 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 Control Channel Verification Module OpenSSL backend
  */
 
 
 #ifndef SSL_VERIFY_OPENSSL_H_
 #define SSL_VERIFY_OPENSSL_H_
 
 #include <openssl/x509.h>

 
 #ifndef __OPENVPN_X509_CERT_T_DECLARED
 #define __OPENVPN_X509_CERT_T_DECLARED
 typedef X509 openvpn_x509_cert_t;
 #endif

 /** @name Function for authenticating a new connection from a remote OpenVPN peer
  *  @{ */
 
 /**
  * Verify that the remote OpenVPN peer's certificate allows setting up a
  * VPN tunnel.
  * @ingroup control_tls
  *
  * This callback function is called every time a new TLS session is being
  * setup to determine whether the remote OpenVPN peer's certificate is
  * allowed to connect. It is called for once for every certificate in the chain.
  * The callback functionality is configured in the \c init_ssl() function, which
  * calls the OpenSSL library's \c SSL_CTX_set_verify() function with \c
  * verify_callback() as its callback argument.
  *
  * It checks preverify_ok, and registers the certificate hash. If these steps
  * succeed, it calls the \c verify_cert() function, which performs
  * OpenVPN-specific verification.
  *
  * @param preverify_ok - Whether the remote OpenVPN peer's certificate
  *                       past verification.  A value of 1 means it
  *                       verified successfully, 0 means it failed.
  * @param ctx          - The complete context used by the OpenSSL library
  *                       to verify the certificate chain.
  *
  * @return The return value indicates whether the supplied certificate is
  *     allowed to set up a VPN tunnel.  The following values can be
  *     returned:
  *      - \c 0: failure, this certificate is not allowed to connect.
  *      - \c 1: success, this certificate is allowed to connect.
  */

 int verify_callback(int preverify_ok, X509_STORE_CTX *ctx);

 
 /** @} name Function for authenticating a new connection from a remote OpenVPN peer */
 

 #endif /* SSL_VERIFY_OPENSSL_H_ */