/*
 * Copyright (C) 2001-2005  Rochester Institute of Technology
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 St, Fifth Floor, Boston, MA  02110-1301  USA
 */

/*
 * Author:		Matt Campbell
 * Descrip:		SSL connection routines
 */

/* Enter only if --with-ssl was specified to the configure script */
#ifdef HAVE_SSL

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#if HAVE_INTTYPES_H
#include <inttypes.h>
#else
# if HAVE_STDINT_H
# include <stdint.h>
# else
typedef unsigned int uint32_t;
# endif
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#ifdef HAVE_TIME_H
#include <time.h>
#endif

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef WIN32
#include <io.h>
typedef unsigned int uint32_t;
#else
#endif

#ifdef HAVE_OPENSSL_RAND_H
#include <openssl/rand.h>
#endif

#ifdef HAVE_OPENSSL_ERR_H
#include <openssl/err.h>
#endif

#include "nanohttp-common.h"
#include "nanohttp-socket.h"
#include "nanohttp-ssl.h"

#define MAXCHUNK 1024
#define HEADER_LEN 5
char HEADER[HEADER_LEN] = { 186, 84, 202, 86, 224 };
static char *pass;

/*
 * superseed
 * Creates a 1k random seed and uses it to seed
 * the SSL random number generator
 */

void
superseed ()
{
  int buf[256], i;

  srand (time (NULL));

  for (i = 0; i < 256; i++)
  {
    buf[i] = rand ();
  }
  RAND_seed ((unsigned char *) buf, sizeof (buf));
}

static int
pw_cb (char *buf, int num, int rwflag, void *userdata)
{
  if (num < (int) strlen (pass) + 1)
    return (0);

  strcpy (buf, pass);
  return strlen (pass);
}

int
verify_sn (X509 * cert, int who, int nid, char *str)
{
  char name[256];
  char buf[256];

  memset (name, '\0', 256);
  memset (buf, '\0', 256);

  if (who == CERT_SUBJECT)
  {
    X509_NAME_oneline (X509_get_subject_name (cert), name, 256);
  }
  else
  {
    X509_NAME_oneline (X509_get_issuer_name (cert), name, 256);
  }

  buf[0] = '/';
  strcat (buf, OBJ_nid2sn (nid));
  strcat (buf, "=");
  strcat (buf, str);

  if (strstr (name, buf))
  {
    return 1;
  }
  else
  {
    return 0;
  }
}

#ifdef NOUSER_VERIFY
static int
user_verify (X509 * cert)
{
  // TODO: Make sure that the client is providing a client cert,
  // or that the Module is providing the Module cert
  /* connect to anyone */
  log_verbose1 ("Validating certificate.");
  return 1;
}
#endif

static int
verify_cb (int prev_ok, X509_STORE_CTX * ctx)
{
/*
    if ((X509_STORE_CTX_get_error(ctx) = X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN))
    {
        log_verbose1("Self signed cert in chain");
        return 1;
    }
*/
#ifdef NOUSER_VERIFY            /* ifdef's added by Ferhat. because of
                                   unresolved reference while compiling */
  if (X509_STORE_CTX_get_error_depth(ctx) == 0)
  {
    return user_verify (X509_STORE_CTX_get_current_cert(ctx));
  }
  else
  {
#endif
    log_verbose1 ("Cert ok (prev)");
    return prev_ok;
#ifdef NOUSER_VERIFY
  }
#endif
}

void
start_ssl( void )
{
  /* Global system initialization */
  log_verbose1 ("Initializing library");
  SSL_library_init ();
  SSL_load_error_strings ();
  ERR_load_crypto_strings ();
  OpenSSL_add_ssl_algorithms ();

  return;
}

SSL_CTX *
initialize_ctx (const char *keyfile, const char *password, const char *calist)
{
  SSL_CTX *ctx = NULL;

  if (password == NULL)
    password = "";
 
  /* Create our context */
  ctx = SSL_CTX_new (SSLv23_method ());

  if (ctx == NULL)
  {
    log_error1 ("Cannot create SSL context");
    return NULL;
  }
  log_verbose1 ("SSL context created ok");

  /* Load our keys and certificates */
  if (keyfile != NULL && password != NULL)
  {

    if (!(SSL_CTX_use_certificate_file (ctx, keyfile, SSL_FILETYPE_PEM)))
    {
      log_error2 ("Couldn't read certificate file: %s", keyfile);
      SSL_CTX_free (ctx);
      return ctx = NULL;
    }

    log_verbose1 ("Certificate file read ok");

    pass = strdup(password);
    SSL_CTX_set_default_passwd_cb (ctx, pw_cb);

    if (!(SSL_CTX_use_PrivateKey_file (ctx, keyfile, SSL_FILETYPE_PEM)))
    {
      log_error2 ("Couldn't read key file: %s", keyfile);
      SSL_CTX_free (ctx);
      return ctx = NULL;
    }

    log_verbose1 ("Keyfile read ok");
  }
  if (calist != NULL && *calist != '\0')
  {

    /* Load the CAs we trust */
    if (!(SSL_CTX_load_verify_locations (ctx, calist, NULL)))
    {
      log_error2 ("Couldn't read CA list: %s", calist);
      SSL_CTX_free (ctx);
      return ctx = NULL;
    }

    SSL_CTX_set_client_CA_list (ctx, SSL_load_client_CA_file (calist));
    log_verbose1 ("Certificate Authority contacted");

  }
  SSL_CTX_set_verify (ctx, SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE,
                      verify_cb);
  log_verbose1 ("Verify callback registered");

  SSL_CTX_set_session_cache_mode (ctx, SSL_SESS_CACHE_OFF);


  /* Load randomness */
  superseed ();

  return ctx;
}

void
log_ssl_error (SSL * ssl, int ret)
{
  int errqueue;
  char errorbuf[256] = "Error: ";

  if (ret == 0)
  {
    log_error1 ("SSL handshake was not successful, contolled shutdown");
  }
  else if (ret == -1)
  {
    log_error1 ("SSL handshake was not successful, fatal error at protocol");
  }

  errqueue = SSL_get_error (ssl, ret);

  switch (errqueue)
  {
  case SSL_ERROR_NONE:
    strcat (errorbuf, "None");
    break;
  case SSL_ERROR_ZERO_RETURN:
    strcat (errorbuf, "Zero return");
    break;
  case SSL_ERROR_WANT_READ:
    strcat (errorbuf, "Want read");
    break;
  case SSL_ERROR_WANT_WRITE:
    strcat (errorbuf, "Want write");
    break;
  case SSL_ERROR_WANT_X509_LOOKUP:
    strcat (errorbuf, "Want x509 lookup");
    break;
  case SSL_ERROR_SYSCALL:
    strcat (errorbuf, "Syscall:");
    if (ret == 0)
    {
      strcat (errorbuf, "Protocol violation");
    }
    else if (ret == -1)
    {
      strcat (errorbuf, "BIO reported an I/O error");
    }
    else
    {
      strcat (errorbuf, "Unknown syscall error");
    }                           /* if */

    break;
  case SSL_ERROR_SSL:
    strcat (errorbuf, "SSL library");
    while ((errqueue = ERR_get_error()))
    {
      log_error2 ("SSL %s", ERR_error_string (errqueue, NULL));
    }
    break;
  }                             /* switch code */

  log_error1 (errorbuf);
}

SSL *
init_ssl (SSL_CTX * ctx, int sock, int type)
{
  int ret;
  SSL *ssl;
#if 0
#ifdef WIN32
  BIO *rbio;
  BIO *wbio;
#else
  BIO *sbio;
#endif
#endif

  log_verbose1 ("Starting SSL Initialization");

  ssl = SSL_new (ctx);

  if (ssl == NULL)
  {
    log_error1 ("Cannot create new ssl object");
    return NULL;
  }

#if 0
#ifdef WIN32
  log_error1 ("Setting up BIO with socket");
  rbio = BIO_new_socket (sock, BIO_NOCLOSE);
  if (rbio == NULL)
  {
    log_error1 ("BIO_new_socket failed");
    return NULL;
  }
  SSL_set_bio (ssl, rbio, rbio);

#else
  sbio = BIO_new_socket (sock, BIO_NOCLOSE);

  if (sbio == NULL)
  {
    log_error1 ("BIO_new_socket failed");
    return NULL;
  }
  SSL_set_bio (ssl, sbio, sbio);
#endif
#endif
  SSL_set_fd (ssl, sock);

  if (type == SSL_SERVER)
  {
    hsocket_t sock_t;
    sock_t.sock = sock;
    hsocket_block (sock_t, 1);
    ret = SSL_accept (ssl);
    hsocket_block (sock_t, 0);
    if (ret <= 0)
    {
      log_error1 ("SSL accept error");
      log_ssl_error (ssl, ret);
      SSL_free (ssl);
      return NULL;
    }                           /* if error */
  }
  else
  {                             /* client */
    ret = SSL_connect (ssl);
    if (ret <= 0)
    {
      log_error1 ("SSL connect error");
      log_ssl_error (ssl, ret);
      SSL_free (ssl);
      return NULL;
    }                           /* if error */
    /* SSL_connect should take care of this for us.
       if(SSL_get_peer_certificate(ssl) == NULL) { log_error1( "No
       certificate provided"); SSL_free(ssl); return ssl = NULL; }
       if(SSL_get_verify_result(ssl) != X509_V_OK) { log_error1( "Certificate 
       did not verify"); SSL_free(ssl); return ssl = NULL; } */
  }

  log_verbose1 ("Completed SSL Initialization");
  return ssl;
}

void
ssl_cleanup (SSL * ssl)
{
  /* does nothing to context */

  if (ssl != NULL)
  {

    SSL_shutdown (ssl);
//        SSL_clear(ssl);
    SSL_free (ssl);
    ssl = NULL;
  }
}

int
ssl_checkFatal( SSL *ssl, int status ){
  switch (SSL_get_error(ssl, status)) {
	case SSL_ERROR_ZERO_RETURN:
	case SSL_ERROR_SSL:
	case SSL_ERROR_SYSCALL:
        return 1;
        break;
    default:
        return 0;
  }
}

#endif /* end of ifdef HAVE_SSL */