/*
 * Copyright (C) 2004-2012 Free Software Foundation, Inc.
 * Copyright (C) 2013 Adam Sampson <ats@offog.org>
 * Copyright (C) 2013 Nikos Mavrogiannopoulos
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file is part of GnuTLS.
 *
 * GnuTLS 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 3 of the License, or
 * (at your option) any later version.
 *
 * GnuTLS 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 GnuTLS; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */

/* Parts copied from GnuTLS example programs. */

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

#include <stdio.h>
#include <stdlib.h>

#if defined(_WIN32)

/* socketpair isn't supported on Win32. */
int
main (int argc, char** argv)
{
    exit (77);
}

#else

#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#if !defined(_WIN32)
#include <sys/wait.h>
#endif
#include <unistd.h>
#include <gnutls/gnutls.h>

#include "utils.h"

/* A very basic TLS client, with PSK authentication.
 */

const char* side = "";

static void
tls_log_func (int level, const char *str)
{
  fprintf (stderr, "%s|<%d>| %s", side, level, str);
}

#define MAX_BUF 1024
#define MSG "Hello TLS"

static void
client (int sd)
{
  int ret, ii;
  gnutls_session_t session;
  gnutls_certificate_credentials_t clientx509cred;
  char buffer[MAX_BUF + 1];
  gnutls_psk_client_credentials_t pskcred;
  /* Need to enable anonymous KX specifically. */
  const gnutls_datum_t key = { (void *) "DEADBEEF", 8 };

  global_init ();
  gnutls_global_set_log_function (tls_log_func);
  if (debug)
    gnutls_global_set_log_level (4711);
    
  side = "client";

  gnutls_certificate_allocate_credentials (&clientx509cred);

  gnutls_psk_allocate_client_credentials (&pskcred);
  gnutls_psk_set_client_credentials (pskcred, "test", &key,
                                     GNUTLS_PSK_KEY_HEX);

  /* Initialize TLS session
   */
  gnutls_init (&session, GNUTLS_CLIENT);

  /* Use default priorities */
  gnutls_priority_set_direct (session, "NORMAL:-KX-ALL:+RSA-PSK", NULL);

  /* put the anonymous credentials to the current session
   */
  gnutls_credentials_set (session, GNUTLS_CRD_PSK, pskcred);
  gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, clientx509cred);

  gnutls_transport_set_int (session, sd);

  /* Perform the TLS handshake
   */
  ret = gnutls_handshake (session);

  if (ret < 0)
    {
      fail ("client: Handshake failed\n");
      gnutls_perror (ret);
      goto end;
    }
  else
    {
      if (debug)
        success ("client: Handshake was completed\n");
    }

  gnutls_record_send (session, MSG, strlen (MSG));

  ret = gnutls_record_recv (session, buffer, MAX_BUF);
  if (ret == 0)
    {
      if (debug)
        success ("client: Peer has closed the TLS connection\n");
      goto end;
    }
  else if (ret < 0)
    {
      fail ("client: Error: %s\n", gnutls_strerror (ret));
      goto end;
    }

  if (debug)
    {
      printf ("- Received %d bytes: ", ret);
      for (ii = 0; ii < ret; ii++)
        {
          fputc (buffer[ii], stdout);
        }
      fputs ("\n", stdout);
    }

  gnutls_bye (session, GNUTLS_SHUT_RDWR);

end:

  close (sd);

  gnutls_deinit (session);

  gnutls_psk_free_client_credentials (pskcred);
  gnutls_certificate_free_credentials (clientx509cred);

  gnutls_global_deinit ();
}

/* This is a sample TLS 1.0 echo server, for PSK authentication.
 */

#define MAX_BUF 1024

static unsigned char server_cert_pem[] =
  "-----BEGIN CERTIFICATE-----\n"
  "MIICVjCCAcGgAwIBAgIERiYdMTALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
  "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTIxWhcNMDgwNDE3MTMyOTIxWjA3MRsw\n"
  "GQYDVQQKExJHbnVUTFMgdGVzdCBzZXJ2ZXIxGDAWBgNVBAMTD3Rlc3QuZ251dGxz\n"
  "Lm9yZzCBnDALBgkqhkiG9w0BAQEDgYwAMIGIAoGA17pcr6MM8C6pJ1aqU46o63+B\n"
  "dUxrmL5K6rce+EvDasTaDQC46kwTHzYWk95y78akXrJutsoKiFV1kJbtple8DDt2\n"
  "DZcevensf9Op7PuFZKBroEjOd35znDET/z3IrqVgbtm2jFqab7a+n2q9p/CgMyf1\n"
  "tx2S5Zacc1LWn9bIjrECAwEAAaOBkzCBkDAMBgNVHRMBAf8EAjAAMBoGA1UdEQQT\n"
  "MBGCD3Rlc3QuZ251dGxzLm9yZzATBgNVHSUEDDAKBggrBgEFBQcDATAPBgNVHQ8B\n"
  "Af8EBQMDB6AAMB0GA1UdDgQWBBTrx0Vu5fglyoyNgw106YbU3VW0dTAfBgNVHSME\n"
  "GDAWgBTpPBz7rZJu5gakViyi4cBTJ8jylTALBgkqhkiG9w0BAQUDgYEAaFEPTt+7\n"
  "bzvBuOf7+QmeQcn29kT6Bsyh1RHJXf8KTk5QRfwp6ogbp94JQWcNQ/S7YDFHglD1\n"
  "AwUNBRXwd3riUsMnsxgeSDxYBfJYbDLeohNBsqaPDJb7XailWbMQKfAbFQ8cnOxg\n"
  "rOKLUQRWJ0K3HyXRMhbqjdLIaQiCvQLuizo=\n" "-----END CERTIFICATE-----\n";

const gnutls_datum_t server_cert = { server_cert_pem,
  sizeof (server_cert_pem)
};

static unsigned char server_key_pem[] =
  "-----BEGIN RSA PRIVATE KEY-----\n"
  "MIICXAIBAAKBgQDXulyvowzwLqknVqpTjqjrf4F1TGuYvkrqtx74S8NqxNoNALjq\n"
  "TBMfNhaT3nLvxqResm62ygqIVXWQlu2mV7wMO3YNlx696ex/06ns+4VkoGugSM53\n"
  "fnOcMRP/PciupWBu2baMWppvtr6far2n8KAzJ/W3HZLllpxzUtaf1siOsQIDAQAB\n"
  "AoGAYAFyKkAYC/PYF8e7+X+tsVCHXppp8AoP8TEZuUqOZz/AArVlle/ROrypg5kl\n"
  "8YunrvUdzH9R/KZ7saNZlAPLjZyFG9beL/am6Ai7q7Ma5HMqjGU8kTEGwD7K+lbG\n"
  "iomokKMOl+kkbY/2sI5Czmbm+/PqLXOjtVc5RAsdbgvtmvkCQQDdV5QuU8jap8Hs\n"
  "Eodv/tLJ2z4+SKCV2k/7FXSKWe0vlrq0cl2qZfoTUYRnKRBcWxc9o92DxK44wgPi\n"
  "oMQS+O7fAkEA+YG+K9e60sj1K4NYbMPAbYILbZxORDecvP8lcphvwkOVUqbmxOGh\n"
  "XRmTZUuhBrJhJKKf6u7gf3KWlPl6ShKEbwJASC118cF6nurTjuLf7YKARDjNTEws\n"
  "qZEeQbdWYINAmCMj0RH2P0mvybrsXSOD5UoDAyO7aWuqkHGcCLv6FGG+qwJAOVqq\n"
  "tXdUucl6GjOKKw5geIvRRrQMhb/m5scb+5iw8A4LEEHPgGiBaF5NtJZLALgWfo5n\n"
  "hmC8+G8F0F78znQtPwJBANexu+Tg5KfOnzSILJMo3oXiXhf5PqXIDmbN0BKyCKAQ\n"
  "LfkcEcUbVfmDaHpvzwY9VEaoMOKVLitETXdNSxVpvWM=\n"
  "-----END RSA PRIVATE KEY-----\n";

const gnutls_datum_t server_key = { server_key_pem,
  sizeof (server_key_pem)
};

/* These are global */
gnutls_psk_server_credentials_t server_pskcred;

static gnutls_session_t
initialize_tls_session (void)
{
  gnutls_session_t session;

  gnutls_init (&session, GNUTLS_SERVER);

  /* avoid calling all the priority functions, since the defaults
   * are adequate.
   */
  gnutls_priority_set_direct (session, "NORMAL:-KX-ALL:+RSA-PSK", NULL);

  gnutls_credentials_set (session, GNUTLS_CRD_PSK, server_pskcred);

  return session;
}

static int
pskfunc (gnutls_session_t session, const char *username, gnutls_datum_t * key)
{
  if (debug)
    printf ("psk: username %s\n", username);
  key->data = gnutls_malloc (4);
  key->data[0] = 0xDE;
  key->data[1] = 0xAD;
  key->data[2] = 0xBE;
  key->data[3] = 0xEF;
  key->size = 4;
  return 0;
}

int err, ret;
char topbuf[512];
gnutls_session_t session;
char buffer[MAX_BUF + 1];
int optval = 1;

static void
server (int sd)
{
  gnutls_certificate_credentials_t serverx509cred;

  /* this must be called once in the program
   */
  global_init ();
  gnutls_global_set_log_function (tls_log_func);
  if (debug)
    gnutls_global_set_log_level (4711);
    
  side = "server";

  gnutls_psk_allocate_server_credentials (&server_pskcred);
  gnutls_psk_set_server_credentials_function (server_pskcred, pskfunc);
  gnutls_certificate_allocate_credentials (&serverx509cred);
  gnutls_certificate_set_x509_key_mem (serverx509cred,
                                       &server_cert, &server_key,
                                       GNUTLS_X509_FMT_PEM);

  session = initialize_tls_session ();

  gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, serverx509cred);

  gnutls_transport_set_int (session, sd);
  ret = gnutls_handshake (session);
  if (ret < 0)
    {
      close (sd);
      gnutls_deinit (session);
      fail ("server: Handshake has failed (%s)\n\n", gnutls_strerror (ret));
      return;
    }
  if (debug)
    success ("server: Handshake was completed\n");

  /* see the Getting peer's information example */
  /* print_info(session); */

  for (;;)
    {
      memset (buffer, 0, MAX_BUF + 1);
      ret = gnutls_record_recv (session, buffer, MAX_BUF);

      if (ret == 0)
        {
          if (debug)
            success ("server: Peer has closed the GnuTLS connection\n");
          break;
        }
      else if (ret < 0)
        {
          fail ("server: Received corrupted data(%d). Closing...\n", ret);
          break;
        }
      else if (ret > 0)
        {
          /* echo data back to the client
           */
          gnutls_record_send (session, buffer, strlen (buffer));
        }
    }
  /* do not wait for the peer to close the connection.
   */
  gnutls_bye (session, GNUTLS_SHUT_WR);

  close (sd);
  gnutls_deinit (session);

  gnutls_psk_free_server_credentials (server_pskcred);
  gnutls_certificate_free_credentials (serverx509cred);

  gnutls_global_deinit ();

  if (debug)
    success ("server: finished\n");
}

void
doit (void)
{
  pid_t child;
  int sockets[2];

  err = socketpair (AF_UNIX, SOCK_STREAM, 0, sockets);
  if (err == -1)
    {
      perror ("socketpair");
      fail ("socketpair failed\n");
      return;
    }

  child = fork ();
  if (child < 0)
    {
      perror ("fork");
      fail ("fork");
      return;
    }

  if (child)
    {
      int status;
      /* parent */
      server (sockets[0]);
      wait (&status);
    }
  else
    client (sockets[1]);
}

#endif /* _WIN32 */