gnunet/src/hostlist/gnunet-daemon-hostlist.c

/*
     This file is part of GNUnet.
     (C) 2007, 2008, 2009, 2014 Christian Grothoff (and other contributing authors)

     GNUnet 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, 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
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file hostlist/gnunet-daemon-hostlist.c
 * @brief code for bootstrapping via hostlist servers
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet-daemon-hostlist_client.h"
#include "gnunet_core_service.h"
#include "gnunet_util_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_statistics_service.h"

#if HAVE_MHD

#include "gnunet-daemon-hostlist_server.h"

/**
 * Set if we are allowed to advertise our hostlist to others.
 */
static int advertising;

/**
 * Set if the user wants us to run a hostlist server.
 */
static int provide_hostlist;

/**
 * Handle to hostlist server's connect handler
 */
static GNUNET_CORE_ConnectEventHandler server_ch;

/**
 * Handle to hostlist server's disconnect handler
 */
static GNUNET_CORE_DisconnectEventHandler server_dh;

#endif

/**
 * Set if we are allowed to learn about peers by accessing
 * hostlist servers.
 */
static int bootstrapping;

/**
 * Set if the user allows us to learn about new hostlists
 * from the network.
 */
static int learning;

/**
 * Statistics handle.
 */
static struct GNUNET_STATISTICS_Handle *stats;

/**
 * Handle to the core service (NULL until we've connected to it).
 */
static struct GNUNET_CORE_Handle *core;

/**
 * Handle to the hostlist client's advertisement handler
 */
static GNUNET_CORE_MessageCallback client_adv_handler;

/**
 * Handle to hostlist client's connect handler
 */
static GNUNET_CORE_ConnectEventHandler client_ch;

/**
 * Handle to hostlist client's disconnect handler
 */
static GNUNET_CORE_DisconnectEventHandler client_dh;

GNUNET_NETWORK_STRUCT_BEGIN

/**
 * A HOSTLIST_ADV message is used to exchange information about
 * hostlist advertisements.  This struct is always
 * followed by the actual url under which the hostlist can be obtained:
 *
 * 1) transport-name (0-terminated)
 * 2) address-length (uint32_t, network byte order; possibly
 *    unaligned!)
 * 3) address expiration (GNUNET_TIME_AbsoluteNBO); possibly
 *    unaligned!)
 * 4) address (address-length bytes; possibly unaligned!)
 */
struct GNUNET_HOSTLIST_ADV_Message
{
  /**
   * Type will be GNUNET_MESSAGE_TYPE_HOSTLIST_ADVERTISEMENT.
   */
  struct GNUNET_MessageHeader header;

  /**
   * Always zero (for alignment).
   */
  uint32_t reserved GNUNET_PACKED;
};
GNUNET_NETWORK_STRUCT_END


/**
 * Our own peer identity.
 */
static struct GNUNET_PeerIdentity me;


/**
 * Callback invoked once our connection to CORE service is up.
 *
 * @param cls NULL
 * @param my_identity our peer's identity
 */
static void
core_init (void *cls,
           const struct GNUNET_PeerIdentity *my_identity)
{
  me = *my_identity;
}


/**
 * Core handler for p2p hostlist advertisements
 *
 * @param cls closure
 * @param peer identity of the sender
 * @param message advertisement message we got
 * @return #GNUNET_OK on success
 */
static int
advertisement_handler (void *cls,
                       const struct GNUNET_PeerIdentity *peer,
                       const struct GNUNET_MessageHeader *message)
{
  GNUNET_assert (NULL != client_adv_handler);
  return (*client_adv_handler) (cls, peer, message);
}


/**
 * Method called whenever a given peer connects.  Wrapper to call both
 * client's and server's functions
 *
 * @param cls closure
 * @param peer peer identity this notification is about
 */
static void
connect_handler (void *cls, const struct GNUNET_PeerIdentity *peer)
{
  if (0 == memcmp (&me, peer, sizeof (struct GNUNET_PeerIdentity)))
    return;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "A new peer connected, notifying client and server\n");
  if (NULL != client_ch)
    (*client_ch) (cls, peer);
#if HAVE_MHD
  if (NULL != server_ch)
    (*server_ch) (cls, peer);
#endif
}


/**
 * Method called whenever a given peer disconnects. Wrapper to call
 * both client's and server's functions
 *
 * @param cls closure
 * @param peer peer identity this notification is about
 */
static void
disconnect_handler (void *cls,
                    const struct GNUNET_PeerIdentity *peer)
{
  if (0 == memcmp (&me, peer, sizeof (struct GNUNET_PeerIdentity)))
    return;
  /* call hostlist client disconnect handler */
  if (NULL != client_dh)
    (*client_dh) (cls, peer);
#if HAVE_MHD
  /* call hostlist server disconnect handler */
  if (NULL != server_dh)
    (*server_dh) (cls, peer);
#endif
}


/**
 * Last task run during shutdown.  Disconnects us from
 * the other services.
 *
 * @param cls NULL
 * @param tc scheduler context
 */
static void
cleaning_task (void *cls,
               const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Hostlist daemon is shutting down\n");
  if (NULL != core)
  {
    GNUNET_CORE_disconnect (core);
    core = NULL;
  }
  if (bootstrapping)
  {
    GNUNET_HOSTLIST_client_stop ();
  }
#if HAVE_MHD
  if (provide_hostlist)
  {
    GNUNET_HOSTLIST_server_stop ();
  }
#endif
  if (NULL != stats)
  {
    GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
    stats = NULL;
  }
}


/**
 * Main function that will be run.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param cfg configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  static const struct GNUNET_CORE_MessageHandler learn_handlers[] = {
    {&advertisement_handler, GNUNET_MESSAGE_TYPE_HOSTLIST_ADVERTISEMENT, 0},
    {NULL, 0, 0}
  };
  static const struct GNUNET_CORE_MessageHandler no_learn_handlers[] = {
    {NULL, 0, 0}
  };
  if ((! bootstrapping) && (! learning)
#if HAVE_MHD
      && (! provide_hostlist)
#endif
      )
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _("None of the functions for the hostlist daemon were enabled.  I have no reason to run!\n"));
    return;
  }
  stats = GNUNET_STATISTICS_create ("hostlist", cfg);
  if (bootstrapping)
    GNUNET_HOSTLIST_client_start (cfg, stats, &client_ch, &client_dh,
                                  &client_adv_handler, learning);
  core =
    GNUNET_CORE_connect (cfg, NULL,
			 &core_init,
			 &connect_handler,
			 &disconnect_handler, NULL,
			 GNUNET_NO, NULL,
			 GNUNET_NO,
			 learning ? learn_handlers : no_learn_handlers);


#if HAVE_MHD
  if (provide_hostlist)
    GNUNET_HOSTLIST_server_start (cfg, stats, core, &server_ch, &server_dh,
                                  advertising);
#endif
  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
				&cleaning_task,
                                NULL);

  if (NULL == core)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _("Failed to connect to `%s' service.\n"), "core");
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
}


/**
 * The main function for the hostlist daemon.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main (int argc, char *const *argv)
{
  static const struct GNUNET_GETOPT_CommandLineOption options[] = {
#if HAVE_MHD
    {'a', "advertise", NULL,
     gettext_noop ("advertise our hostlist to other peers"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &advertising},
#endif
    {'b', "bootstrap", NULL,
     gettext_noop
     ("bootstrap using hostlists (it is highly recommended that you always use this option)"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &bootstrapping},
    {'e', "enable-learning", NULL,
     gettext_noop ("enable learning about hostlist servers from other peers"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &learning},
#if HAVE_MHD
    {'p', "provide-hostlist", NULL,
     gettext_noop ("provide a hostlist server"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &provide_hostlist},
#endif
    GNUNET_GETOPT_OPTION_END
  };

  int ret;

  if (GNUNET_OK != GNUNET_STRINGS_get_utf8_args (argc, argv, &argc, &argv))
    return 2;

  GNUNET_log_setup ("hostlist", "WARNING", NULL);
  ret =
      (GNUNET_OK ==
       GNUNET_PROGRAM_run (argc, argv, "hostlist",
                           _("GNUnet hostlist server and client"),
                           options,
                           &run, NULL)) ? 0 : 1;
  GNUNET_free ((void*) argv);
  return ret;
}

/* end of gnunet-daemon-hostlist.c */