/*
 * Copyright (C) 2012 Free Software Foundation, Inc.
 *
 * 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
 */

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

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

#if defined(_WIN32)

int main()
{
  exit(77);
}

#else

#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#include <gnutls/dtls.h>
#include <signal.h>

#include "utils.h"

/* This program tests whether a DTLS handshake would timeout
 * in a minute.
 */

static void print_type(const unsigned char* buf, int size)
{
  if (buf[0] == 22 && size >= 13) {
    if (buf[13] == 1)
      fprintf(stderr, "Client Hello\n");
    else if (buf[13] == 2)
      fprintf(stderr, "Server Hello\n");
    else if (buf[13] == 12)
      fprintf(stderr, "Server Key exchange\n");
    else if (buf[13] == 14)
      fprintf(stderr, "Server Hello Done\n");
    else if (buf[13] == 11)
      fprintf(stderr, "Certificate\n");
    else if (buf[13] == 16)
      fprintf(stderr, "Client Key Exchange\n");
    else if (buf[4] == 1)
      fprintf(stderr, "Finished\n");
    else if (buf[13] == 11)
      fprintf(stderr, "Server Hello Done\n");
    else
      fprintf(stderr, "Unknown handshake\n");
  } else if (buf[0] == 20) {
    fprintf(stderr, "Change Cipher Spec\n");
  } else
    fprintf(stderr, "Unknown\n");
}

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

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

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

static int counter;
static int packet_to_lose;
gnutls_session_t session;

static ssize_t
push (gnutls_transport_ptr_t tr, const void *data, size_t len)
{
int fd = (long int)tr;

  counter++;

  if (packet_to_lose != -1 && packet_to_lose == counter) {
    if (debug)
      {
        fprintf(stderr, "Discarding packet %d: ", counter);
        print_type(data, len);
      }
      
    packet_to_lose = 1;
    counter = 0;
    return len;
  }
  return send(fd, data, len, 0);
}

static void
client (int fd, int packet)
{
  int ret;
  gnutls_anon_client_credentials_t anoncred;
  /* Need to enable anonymous KX specifically. */

  gnutls_global_init ();

  if (debug)
    {
      gnutls_global_set_log_function (client_log_func);
      gnutls_global_set_log_level (4711);
    }

  gnutls_anon_allocate_client_credentials (&anoncred);

  /* Initialize TLS session
   */
  gnutls_init (&session, GNUTLS_CLIENT|GNUTLS_DATAGRAM);
  gnutls_dtls_set_mtu( session, 1500);

  /* Use default priorities */
  gnutls_priority_set_direct (session, "NONE:+VERS-DTLS1.0:+CIPHER-ALL:+MAC-ALL:+SIGN-ALL:+COMP-ALL:+ANON-ECDH:+CURVE-ALL", NULL);

  /* put the anonymous credentials to the current session
   */
  gnutls_credentials_set (session, GNUTLS_CRD_ANON, anoncred);

  counter = 0;
  packet_to_lose = packet;

  gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) fd);
  gnutls_transport_set_push_function (session, push);

  /* Perform the TLS handshake
   */
  do 
    {
      ret = gnutls_handshake (session);
    }
  while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
  
  gnutls_deinit(session);
  gnutls_global_deinit();

  if (ret < 0)
    {
      if (ret == GNUTLS_E_TIMEDOUT) return;
      fail ("client: Handshake failed\n");
      gnutls_perror (ret);
      exit(1);
    }
  else
    {
      if (debug)
        success ("client: Handshake was completed\n");
    }

  exit(1);
}


/* These are global */
gnutls_anon_server_credentials_t anoncred;
pid_t child;

static gnutls_session_t
initialize_tls_session (void)
{
  gnutls_session_t session;

  gnutls_init (&session, GNUTLS_SERVER|GNUTLS_DATAGRAM);
  gnutls_dtls_set_mtu( session, 1500);

  /* avoid calling all the priority functions, since the defaults
   * are adequate.
   */
  gnutls_priority_set_direct (session, "NONE:+VERS-DTLS1.0:+CIPHER-ALL:+MAC-ALL:+SIGN-ALL:+COMP-ALL:+ANON-ECDH:+CURVE-ALL", NULL);

  gnutls_credentials_set (session, GNUTLS_CRD_ANON, anoncred);

  return session;
}

static void
server (int fd, int packet)
{
int ret;
  /* this must be called once in the program
   */
  gnutls_global_init ();

  if (debug)
    {
      gnutls_global_set_log_function (server_log_func);
      gnutls_global_set_log_level (4711);
    }

  gnutls_anon_allocate_server_credentials (&anoncred);

  session = initialize_tls_session ();

  counter = 0;
  packet_to_lose = packet;

  gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) fd);
  gnutls_transport_set_push_function (session, push);

  do 
    {
      ret = gnutls_handshake (session);
    }
  while (ret < 0 && gnutls_error_is_fatal(ret) == 0);

  gnutls_deinit (session);
  gnutls_global_deinit();

  if (ret < 0)
    {
      return;
    }
}

static void start (int server_packet, int client_packet)
{
  int fd[2];
  int ret;
  
  if (debug)
    fprintf(stderr, "\nWill discard %s packet %d\n", 
      (client_packet!=-1)?"client":"server", (client_packet!=-1)?client_packet:server_packet);
  
  ret = socketpair(AF_UNIX, SOCK_DGRAM, 0, fd);
  if (ret < 0)
    {
      perror("socketpair");
      exit(1);
    }

  child = fork ();
  if (child < 0)
    {
      perror ("fork");
      fail ("fork");
      exit(1);
    }

  if (child)
    {
      /* parent */
      close(fd[1]);
      server (fd[0], server_packet);
      close(fd[0]);
      kill(child, SIGTERM);
    }
  else 
    {
      close(fd[0]);
      client (fd[1], client_packet);
      close(fd[1]);
      exit(0);
    }
}

static void ch_handler(int sig)
{
int status;
  wait(&status);
  if (WEXITSTATUS(status) != 0)
    fail("Child died with status %d\n", WEXITSTATUS(status));
  return;
}

void
doit (void)
{
time_t tstart, tstop;

  signal(SIGCHLD, ch_handler);

  tstart = time(0);
  start(2, -1);

  tstop = time(0);
  
  tstop = tstop - tstart;

  if (!(tstop < 70 && tstop > 55))
    fail("Time difference: %u\n", (unsigned)tstop);
}

#endif /* _WIN32 */