// -*- C++ -*-

//=============================================================================
/**
 *  @file    SSL_Context.h
 *
 *  $Id$
 *
 *  @author Carlos O'Ryan <coryan@ece.uci.edu>
 */
//=============================================================================


#ifndef ACE_SSL_CONTEXT_H
#define ACE_SSL_CONTEXT_H

#include /**/ "ace/pre.h"

#include "SSL_Export.h"

#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

#include "ace/SString.h"

#ifdef ACE_HAS_THREADS
# include "ace/os_include/os_pthread.h"
#endif  /* ACE_HAS_THREADS */

#include <openssl/ssl.h>

#ifdef ACE_HAS_THREADS
extern "C"
{

  /// Mutex locking/unlocking callback for OpenSSL multithread
  /// support.
  void ACE_SSL_locking_callback (int mode,
                                 int type,
                                 const char * file,
                                 int line);

  /// Return the current thread ID.  OpenSSL uses this on platforms
  /// that need it.
  unsigned long ACE_SSL_thread_id (void);
}
#endif  /* ACE_HAS_THREADS */


class ACE_SSL_Export ACE_SSL_Data_File
{
public:

  /// Default constructor
  ACE_SSL_Data_File (void);

  /// Contructor from a file name and the file type.
  ACE_SSL_Data_File (const char *file_name,
                     int type = SSL_FILETYPE_PEM);

  /// The file name
  const char *file_name (void) const;

  /// The type
  int type (void) const;

private:

  /// The file name
  ACE_CString file_name_;

  /// The type, used by the SSL library to parse the file contents.
  int type_;
};

// ****************************************************************


/**
 * @class ACE_SSL_Context
 *
 * @brief A wrapper for the OpenSSL SSL_CTX related functions.
 *
 * This class provides a wrapper for the SSL_CTX data structure.
 * Since most applications have a single SSL_CTX structure, this class
 * can be used as a singleton.
 */
class ACE_SSL_Export ACE_SSL_Context
{
  friend void ACE_SSL_locking_callback (int, int, const char *, int);

public:

  enum {
    INVALID_METHOD = -1,
    SSLv2_client = 1,
    SSLv2_server,
    SSLv2,
    SSLv3_client,
    SSLv3_server,
    SSLv3,
    SSLv23_client,
    SSLv23_server,
    SSLv23,
    TLSv1_client,
    TLSv1_server,
    TLSv1
  };

  /// Constructor
  ACE_SSL_Context (void);

  /// Destructor
  ~ACE_SSL_Context (void);

  /// The Singleton context, the SSL components use the singleton if
  /// nothing else is available.
  static ACE_SSL_Context *instance (void);

  /**
   * Set the CTX mode.  The mode can be set only once, afterwards the
   * function has no effect and returns -1.
   * Once the mode is set the underlying SSL_CTX is initialized and
   * the class can be used.
   * If the mode is not set, then the class automatically initializes
   * itself to the default mode.
   */
  int set_mode (int mode = ACE_SSL_Context::SSLv23);

  int get_mode (void) const;

  /// Get the SSL context
  SSL_CTX *context (void);

  /// Get the file name and file format used for the private key
  int private_key_type (void) const;
  const char *private_key_file_name (void) const;

  /// Set the private key file.
  /**
   * @note This method should only be called after a certificate has
   *       been set since key verification is performed against the
   *       certificate, among other things.
   */
  int private_key (const char *file_name,
                   int type = SSL_FILETYPE_PEM);

  /// Verify that the private key is valid.
  /**
   * @note This method should only be called after a certificate has
   *       been set since key verification is performed against the
   *       certificate, among other things.
   */
  int verify_private_key (void);

  /// Get the file name and file format used for the certificate file
  int certificate_type (void) const;
  const char *certificate_file_name (void) const;

  /// Set the certificate file.
  int certificate (const char *file_name,
                   int type = SSL_FILETYPE_PEM);


  /**
   *  Load the location of the trusted certification authority
   *  certificates.  Note that CA certificates are stored in PEM format
   *  as a sequence of certificates in <ca_file> or as a set of
   *  individual certificates in <ca_dir> (or both).
   *
   *  Note this method is called by set_mode() to load the default
   *  environment settings for <ca_file> and <ca_dir>, if any. This
   *  allows for automatic service configuration (and backward
   *  compatibility with previous versions.
   *
   *  Note that the underlying SSL function will add valid file and
   *  directory names to the load location lists maintained as part of
   *  the SSL_CTX table.  (... It therefore dosn't make sense to keep a
   *  copy of the file and path name of the most recently added
   *  <ca_file> or <ca_path>.
   *
   *  @return 0 for success or -1 on error.
   *
   *  @see OpenSSL manual SSL_CTX_load_verify_locations(3) for a
   *  detailed description of the CA file and directory requirements
   *  and processing.
  */
  int load_trusted_ca(const char* ca_file = 0, const char* ca_dir = 0);

  /**
     Test whether any CA locations have been successfully loaded and
     return the number of successful attempts.

     @return  >0 This value indicates the number of successful CA load
                 attempts .
     @return  0  If all CA load attempts have failed.
  */
  int have_trusted_ca(void) const;


  /**
   *  @todo Complete this documentation where elipses(...) are used
   *
   *  @doc Use this method when certificate chain verification is
   *  required.  The default server behaviour is SSL_VERIFY_NONE
   *  i.e. client certicates are requested for verified. This method
   *  can be used to configure server to request client certificates
   *  and perform the certificate verification. If <strict> is set
   *  true the client connection is rejected when certificate
   *  verification fails.  Otherwise the session is accepted with a
   *  warning, which is the default behaviour.  If <once> is set true
   *  (default), certificates are requested only once per session.
   *  The last parameter <depth> can be used to set the verification
   *  depth.
   *
   *  Note for verification to work correctly there should be a valid
   *  CA name list set using load_trusted_ca().
   *
   *  @see OpenSSL documentation of SSL_CTX_set_verify(3) for details of
   *  the verification process.
   *
   *  @see OpenSSL documentation ... set_verify_depth(3) ...
   *
   *  Note that this method overrides the use of the
   *  default_verify_mode() method.
   */
  void set_verify_peer (int strict = 0,
                        int once = 1,
                        int depth = 0);


  /// TODO: a implementation that will lookup the CTX table for the list
  /// of files and paths etc.
  /// Query the location of trusted certification authority
  /// certificates.
  // const char* ca_file_name(void) const;
  // const char* ca_dir_name(void) const;



  /**
   * Set and query the default verify mode for this context, it is
   * inherited by all the ACE_SSL objects created using the context.
   * It can be overriden on a per-ACE_SSL object.
   */
  void default_verify_mode (int mode);
  int default_verify_mode (void) const;

  /**
   * @name OpenSSL Random Number Generator Seed Related Methods
   *
   * These are methods that can be used to seed OpenSSL's
   * pseudo-random number generator.  These methods can be called more
   * than once.
   */
  //@{
  /// Seed the underlying random number generator.  This value should
  /// have at least 128 bits of entropy.
  int random_seed (const char * seed);

  /// Set the Entropy Gathering Daemon (EGD) UNIX domain socket file to
  /// read random seed values from.
  int egd_file (const char * socket_file);

  /**
   * Set the file that contains the random seed value state, and the
   * amount of bytes to read.  "-1" bytes causes the entire file to be
   * read.
   */
  int seed_file (const char * seed_file, long bytes = -1);
  //@}

  /// Print SSL error corresponding to the given error code.
  static void report_error (unsigned long error_code);

  /// Print the last SSL error for the current thread.
  static void report_error (void);

  /**
   * @name Diffie-Hellman (DH) Parameters
   *
   * When using DSS-based certificates, Diffie-Hellman keys need to be
   * exchanged.  These must be provided in the form of DH key
   * generation parameters loaded in, or as fixed keys hardcoded into
   * the code itself.  ACE_SSL supports loaded parameters.
   *
   */
  //@{
  /**
   * Load Diffie-Hellman parameters from file_name.  The specified file can be
   * a standalone file containing only DH parameters (e.g., as created
   * by <code>openssl dhparam</code>), or it can be a certificate which has
   * a PEM-encoded set of DH params concatenated on to i.
   */
  int dh_params (const char *file_name, int type = SSL_FILETYPE_PEM);
  const char *dh_params_file_name () const;
  int dh_params_file_type () const;
  //@}

private:

  /// Verify if the context has been initialized or not.
  void check_context (void);

  /// @@ More to document
  void ssl_library_init ();
  void ssl_library_fini ();

  // = Prevent assignment and initialization.
  //@{
  ACE_UNIMPLEMENTED_FUNC (void operator= (const ACE_SSL_Context &))
  ACE_UNIMPLEMENTED_FUNC (ACE_SSL_Context (const ACE_SSL_Context &))
  //@}

private:
  // @@ Carlos, I protected this variable with an ACE_GUARD, just like
  //    what we do for the orb_init_count_ variable in
  //    tao/ORB.cpp.   The code isn't pretty but it should suffice
  //    until the SSL context is stored in a Singleton.
  //       -Ossama

  /// The SSL_CTX structure
  SSL_CTX *context_;

  /// Cache the mode so we can answer fast
  int mode_;

  /// The private key, certificate, and Diffie-Hellman paramters files
  ACE_SSL_Data_File private_key_;
  ACE_SSL_Data_File certificate_;
  ACE_SSL_Data_File dh_params_;

  /// The default verify mode.
  int default_verify_mode_;

  /// count of successful CA load attempts
  int have_ca_;

  /// Reference count of the number of times the ACE_SSL_Context was
  /// initialized.
  static int library_init_count_;

  // @@ This should also be done with a singleton, otherwise it is not
  //    thread safe and/or portable to some weird platforms...

#ifdef ACE_HAS_THREADS
  /// Array of mutexes used internally by OpenSSL when the SSL
  /// application is multithreaded.
  static ACE_mutex_t * lock_;

  // @@ This should also be managed by a singleton.
#endif

};

#if defined(__ACE_INLINE__)
#include "SSL_Context.inl"
#endif /* __ACE_INLINE__ */

#include /**/ "ace/post.h"

#endif  /* ACE_SSL_CONTEXT_H */