/*
     This file is part of GNUnet
     Copyright (C) 2007, 2009, 2011, 2012 Christian Grothoff

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */

/**
 * @file test_gnunet_vpn.c
 * @brief testcase for tunneling HTTP over the GNUnet VPN
 * @author Christian Grothoff
 */
#include "platform.h"
/* Just included for the right curl.h */
#include "gnunet_curl_lib.h"
#include <microhttpd.h>
#include "gnunet_vpn_service.h"
#include "gnunet_testing_lib.h"
#include "gnunet_mhd_compat.h"

#define PORT 48080

#define TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 300)


/**
 * Return value for 'main'.
 */
static int global_ret;

static struct GNUNET_VPN_Handle *vpn;

static struct MHD_Daemon *mhd;

static struct GNUNET_SCHEDULER_Task *mhd_task_id;

static struct GNUNET_SCHEDULER_Task *curl_task_id;

static struct GNUNET_SCHEDULER_Task *timeout_task_id;

static struct GNUNET_VPN_RedirectionRequest *rr;

static CURL *curl;

static CURLM *multi;

static char *url;

/**
 * IP address of the ultimate destination.
 */
static const char *dest_ip;

/**
 * Address family of the dest_ip.
 */
static int dest_af;

/**
 * Address family to use by the curl client.
 */
static int src_af;


struct CBC
{
  char buf[1024];
  size_t pos;
};

static struct CBC cbc;


static size_t
copy_buffer (void *ptr, size_t size, size_t nmemb, void *ctx)
{
  struct CBC *cbc = ctx;

  if (cbc->pos + size * nmemb > sizeof(cbc->buf))
    return 0;                   /* overflow */
  GNUNET_memcpy (&cbc->buf[cbc->pos], ptr, size * nmemb);
  cbc->pos += size * nmemb;
  return size * nmemb;
}


static MHD_RESULT
mhd_ahc (void *cls,
         struct MHD_Connection *connection,
         const char *url,
         const char *method,
         const char *version,
         const char *upload_data,
         size_t *upload_data_size,
         void **unused)
{
  static int ptr;
  struct MHD_Response *response;
  int ret;

  if (0 != strcmp ("GET", method))
    return MHD_NO;              /* unexpected method */
  if (&ptr != *unused)
  {
    *unused = &ptr;
    return MHD_YES;
  }
  *unused = NULL;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "MHD sends respose for request to URL `%s'\n", url);
  response =
    MHD_create_response_from_buffer (strlen (url), (void *) url,
                                     MHD_RESPMEM_MUST_COPY);
  ret = MHD_queue_response (connection, MHD_HTTP_OK, response);
  MHD_destroy_response (response);
  if (ret == MHD_NO)
    abort ();
  return ret;
}


static void
do_shutdown (void *cls)
{
  if (NULL != mhd_task_id)
  {
    GNUNET_SCHEDULER_cancel (mhd_task_id);
    mhd_task_id = NULL;
  }
  if (NULL != curl_task_id)
  {
    GNUNET_SCHEDULER_cancel (curl_task_id);
    curl_task_id = NULL;
  }
  if (NULL != timeout_task_id)
  {
    GNUNET_SCHEDULER_cancel (timeout_task_id);
    timeout_task_id = NULL;
  }
  if (NULL != mhd)
  {
    MHD_stop_daemon (mhd);
    mhd = NULL;
  }
  if (NULL != rr)
  {
    GNUNET_VPN_cancel_request (rr);
    rr = NULL;
  }
  if (NULL != vpn)
  {
    GNUNET_VPN_disconnect (vpn);
    vpn = NULL;
  }
  GNUNET_free_non_null (url);
  url = NULL;
}


/**
 * Function to run the HTTP client.
 */
static void
curl_main (void *cls)
{
  fd_set rs;
  fd_set ws;
  fd_set es;
  int max;
  struct GNUNET_NETWORK_FDSet nrs;
  struct GNUNET_NETWORK_FDSet nws;
  struct GNUNET_TIME_Relative delay;
  long timeout;
  int running;
  struct CURLMsg *msg;

  curl_task_id = NULL;
  max = 0;
  FD_ZERO (&rs);
  FD_ZERO (&ws);
  FD_ZERO (&es);
  curl_multi_perform (multi, &running);
  if (running == 0)
  {
    GNUNET_assert (NULL != (msg = curl_multi_info_read (multi, &running)));
    if (msg->msg == CURLMSG_DONE)
    {
      if (msg->data.result != CURLE_OK)
      {
        fprintf (stderr, "%s failed at %s:%d: `%s'\n", "curl_multi_perform",
                 __FILE__, __LINE__, curl_easy_strerror (msg->data.result));
        global_ret = 1;
      }
    }
    curl_multi_remove_handle (multi, curl);
    curl_multi_cleanup (multi);
    curl_easy_cleanup (curl);
    curl = NULL;
    multi = NULL;
    if (cbc.pos != strlen ("/hello_world"))
    {
      GNUNET_break (0);
      global_ret = 2;
    }
    if (0 != strncmp ("/hello_world", cbc.buf, strlen ("/hello_world")))
    {
      GNUNET_break (0);
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "You might want to check if your host-based firewall is blocking the connections.\n");
      global_ret = 3;
    }
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Download complete, shutting down!\n");
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  GNUNET_assert (CURLM_OK == curl_multi_fdset (multi, &rs, &ws, &es, &max));
  if ((CURLM_OK != curl_multi_timeout (multi, &timeout)) || (-1 == timeout))
    delay = GNUNET_TIME_UNIT_SECONDS;
  else
    delay =
      GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS,
                                     (unsigned int) timeout);
  GNUNET_NETWORK_fdset_copy_native (&nrs, &rs, max + 1);
  GNUNET_NETWORK_fdset_copy_native (&nws, &ws, max + 1);
  curl_task_id =
    GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT, delay,
                                 &nrs, &nws, &curl_main, NULL);
}


/**
 * Callback invoked from the VPN service once a redirection is
 * available.  Provides the IP address that can now be used to
 * reach the requested destination (in our case, the MHD server)
 *
 * @param cls closure
 * @param af address family, AF_INET or AF_INET6; AF_UNSPEC on error;
 *                will match 'result_af' from the request
 * @param address IP address (struct in_addr or struct in_addr6, depending on 'af')
 *                that the VPN allocated for the redirection;
 *                traffic to this IP will now be redirected to the
 *                specified target peer; NULL on error
 */
static void
allocation_cb (void *cls, int af, const void *address)
{
  char ips[INET6_ADDRSTRLEN];

  rr = NULL;
  if (src_af != af)
  {
    fprintf (stderr,
             "VPN failed to allocate appropriate address\n");
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  if (AF_INET6 == af)
    GNUNET_asprintf (&url,
                     "http://[%s]:%u/hello_world",
                     inet_ntop (af,
                                address,
                                ips,
                                sizeof(ips)),
                     (unsigned int) PORT);
  else
    GNUNET_asprintf (&url,
                     "http://%s:%u/hello_world",
                     inet_ntop (af,
                                address,
                                ips,
                                sizeof(ips)),
                     (unsigned int) PORT);
  curl = curl_easy_init ();
  curl_easy_setopt (curl, CURLOPT_URL, url);
  curl_easy_setopt (curl, CURLOPT_WRITEFUNCTION, &copy_buffer);
  curl_easy_setopt (curl, CURLOPT_WRITEDATA, &cbc);
  curl_easy_setopt (curl, CURLOPT_FAILONERROR, 1);
  curl_easy_setopt (curl, CURLOPT_TIMEOUT, 150L);
  curl_easy_setopt (curl, CURLOPT_CONNECTTIMEOUT, 15L);
  curl_easy_setopt (curl, CURLOPT_NOSIGNAL, 1);
  curl_easy_setopt (curl, CURLOPT_VERBOSE, 0);

  multi = curl_multi_init ();
  GNUNET_assert (multi != NULL);
  GNUNET_assert (CURLM_OK == curl_multi_add_handle (multi, curl));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Beginning HTTP download from `%s'\n",
              url);
  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
                                &curl_main,
                                NULL);
}


/**
 * Function to keep the HTTP server running.
 */
static void
mhd_main (void);


static void
mhd_task (void *cls)
{
  mhd_task_id = NULL;
  MHD_run (mhd);
  mhd_main ();
}


static void
do_timeout (void *cls)
{
  timeout_task_id = NULL;
  GNUNET_SCHEDULER_shutdown ();
  GNUNET_break (0);
  global_ret = 1;
}


static void
mhd_main ()
{
  struct GNUNET_NETWORK_FDSet nrs;
  struct GNUNET_NETWORK_FDSet nws;
  fd_set rs;
  fd_set ws;
  fd_set es;
  int max_fd;
  unsigned MHD_LONG_LONG timeout;
  struct GNUNET_TIME_Relative delay;

  GNUNET_assert (NULL == mhd_task_id);
  FD_ZERO (&rs);
  FD_ZERO (&ws);
  FD_ZERO (&es);
  max_fd = -1;
  GNUNET_assert (MHD_YES == MHD_get_fdset (mhd, &rs, &ws, &es, &max_fd));
  if (MHD_YES == MHD_get_timeout (mhd, &timeout))
    delay =
      GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS,
                                     (unsigned int) timeout);
  else
    delay = GNUNET_TIME_UNIT_FOREVER_REL;
  GNUNET_NETWORK_fdset_copy_native (&nrs, &rs, max_fd + 1);
  GNUNET_NETWORK_fdset_copy_native (&nws, &ws, max_fd + 1);
  mhd_task_id =
    GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT, delay,
                                 &nrs, &nws, &mhd_task, NULL);
}


static void
run (void *cls,
     const struct GNUNET_CONFIGURATION_Handle *cfg,
     struct GNUNET_TESTING_Peer *peer)
{
  struct in_addr v4;
  struct in6_addr v6;
  void *addr;
  enum MHD_FLAG flags;

  vpn = GNUNET_VPN_connect (cfg);
  GNUNET_assert (NULL != vpn);
  flags = MHD_USE_DEBUG;
  if (AF_INET6 == dest_af)
    flags |= MHD_USE_IPv6;
  mhd =
    MHD_start_daemon (flags, PORT, NULL, NULL, &mhd_ahc, NULL,
                      MHD_OPTION_END);


  GNUNET_assert (NULL != mhd);
  mhd_main ();
  addr = NULL;
  switch (dest_af)
  {
  case AF_INET:
    GNUNET_assert (1 == inet_pton (dest_af, dest_ip, &v4));
    addr = &v4;
    break;

  case AF_INET6:
    GNUNET_assert (1 == inet_pton (dest_af, dest_ip, &v6));
    addr = &v6;
    break;

  default:
    GNUNET_assert (0);
  }
  rr = GNUNET_VPN_redirect_to_ip (vpn, src_af, dest_af, addr,
                                  GNUNET_TIME_UNIT_FOREVER_ABS, &allocation_cb,
                                  NULL);
  timeout_task_id =
    GNUNET_SCHEDULER_add_delayed (TIMEOUT,
                                  &do_timeout,
                                  NULL);
  GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
                                 NULL);
}


int
main (int argc, char *const *argv)
{
  const char *type;
  const char *bin;
  char *vpn_binary;
  char *exit_binary;
  int ret = 0;

  if (0 != access ("/dev/net/tun", R_OK))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
                              "access",
                              "/dev/net/tun");
    fprintf (stderr,
             "WARNING: System unable to run test, skipping.\n");
    return 77;
  }

  vpn_binary = GNUNET_OS_get_libexec_binary_path ("gnunet-helper-vpn");
  exit_binary = GNUNET_OS_get_libexec_binary_path ("gnunet-helper-exit");
  if ((GNUNET_YES != (ret = GNUNET_OS_check_helper_binary (vpn_binary,
                                                           GNUNET_YES,
                                                           "-d gnunet-vpn - - 169.1.3.3.7 255.255.255.0")))
      ||                                                                                                                               // ipv4 only please!
      (GNUNET_YES != (ret = GNUNET_OS_check_helper_binary (exit_binary,
                                                           GNUNET_YES,
                                                           "-d gnunet-vpn - - - 169.1.3.3.7 255.255.255.0"))))                          // no nat, ipv4 only
  {
    GNUNET_free (vpn_binary);
    GNUNET_free (exit_binary);
    fprintf (stderr,
             "WARNING: gnunet-helper-{exit,vpn} binaries are not SUID, refusing to run test (as it would have to fail). %d\n",
             ret);
    return 77;
  }

  GNUNET_free (vpn_binary);
  GNUNET_free (exit_binary);
  bin = argv[0];
  if (NULL != strstr (bin, "lt-"))
    bin = strstr (bin, "lt-") + 4;
  type = strstr (bin, "-");
  if (NULL == type)
  {
    fprintf (stderr,
             "invalid binary name\n");
    return 1;
  }
  type++;
  /* on Windows, .exe is suffixed to these binaries,
   * thus cease comparison after the 6th char.
   */
  if (0 == strncmp (type, "4_to_6", 6))
  {
    dest_ip = "FC5A:04E1:C2BA::1";
    dest_af = AF_INET6;
    src_af = AF_INET;
  }
  else if (0 == strncmp (type, "6_to_4", 6))
  {
    dest_ip = "169.254.86.1";
    dest_af = AF_INET;
    src_af = AF_INET6;
  }
  else if (0 == strncmp (type, "4_over", 6))
  {
    dest_ip = "169.254.86.1";
    dest_af = AF_INET;
    src_af = AF_INET;
  }
  else if (0 == strncmp (type, "6_over", 6))
  {
    dest_ip = "FC5A:04E1:C2BA::1";
    dest_af = AF_INET6;
    src_af = AF_INET6;
  }
  else
  {
    fprintf (stderr, "invalid binary suffix `%s'\n", type);
    return 1;
  }
  if ((GNUNET_OK != GNUNET_NETWORK_test_pf (src_af)) ||
      (GNUNET_OK != GNUNET_NETWORK_test_pf (dest_af)))
  {
    fprintf (stderr,
             "Required address families not supported by this system, skipping test.\n");
    return 0;
  }
  if (0 != curl_global_init (CURL_GLOBAL_WIN32))
  {
    fprintf (stderr, "failed to initialize curl\n");
    return 2;
  }
  if (0 !=
      GNUNET_TESTING_peer_run ("test-gnunet-vpn", "test_gnunet_vpn.conf", &run,
                               NULL))
    return 1;
  GNUNET_DISK_directory_remove ("/tmp/gnunet-test-vpn");
  return global_ret;
}


/* end of test_gnunet_vpn.c */