path: root/src/transport/plugin_transport_template.c

/*
     This file is part of GNUnet
     (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 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 transport/plugin_transport_template.c
 * @brief template for a new transport service
 * @author Christian Grothoff
 */

#include "platform.h"
#include "gnunet_protocols.h"
#include "gnunet_connection_lib.h"
#include "gnunet_server_lib.h"
#include "gnunet_service_lib.h"
#include "gnunet_statistics_service.h"
#include "gnunet_transport_service.h"
#include "gnunet_transport_plugin.h"

#define DEBUG_TEMPLATE GNUNET_EXTRA_LOGGING

/**
 * After how long do we expire an address that we
 * learned from another peer if it is not reconfirmed
 * by anyone?
 */
#define LEARNED_ADDRESS_EXPIRATION GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 6)


/**
 * Encapsulation of all of the state of the plugin.
 */
struct Plugin;


/**
 * Session handle for connections.
 */
struct Session
{

  /**
   * Stored in a linked list.
   */
  struct Session *next;

  /**
   * Pointer to the global plugin struct.
   */
  struct Plugin *plugin;

  /**
   * The client (used to identify this connection)
   */
  /* void *client; */

  /**
   * Continuation function to call once the transmission buffer
   * has again space available.  NULL if there is no
   * continuation to call.
   */
  GNUNET_TRANSPORT_TransmitContinuation transmit_cont;

  /**
   * Closure for transmit_cont.
   */
  void *transmit_cont_cls;

  /**
   * To whom are we talking to (set to our identity
   * if we are still waiting for the welcome message)
   */
  struct GNUNET_PeerIdentity sender;

  /**
   * At what time did we reset last_received last?
   */
  struct GNUNET_TIME_Absolute last_quota_update;

  /**
   * How many bytes have we received since the "last_quota_update"
   * timestamp?
   */
  uint64_t last_received;

  /**
   * Number of bytes per ms that this peer is allowed
   * to send to us.
   */
  uint32_t quota;

};

/**
 * Encapsulation of all of the state of the plugin.
 */
struct Plugin
{
  /**
   * Our environment.
   */
  struct GNUNET_TRANSPORT_PluginEnvironment *env;

  /**
   * List of open sessions.
   */
  struct Session *sessions;

};


/**
 * Function that can be used by the transport service to transmit
 * a message using the plugin.   Note that in the case of a
 * peer disconnecting, the continuation MUST be called
 * prior to the disconnect notification itself.  This function
 * will be called with this peer's HELLO message to initiate
 * a fresh connection to another peer.
 *
 * @param cls closure
 * @param session which session must be used
 * @param msgbuf the message to transmit
 * @param msgbuf_size number of bytes in 'msgbuf'
 * @param priority how important is the message (most plugins will
 *                 ignore message priority and just FIFO)
 * @param to how long to wait at most for the transmission (does not
 *                require plugins to discard the message after the timeout,
 *                just advisory for the desired delay; most plugins will ignore
 *                this as well)
 * @param cont continuation to call once the message has
 *        been transmitted (or if the transport is ready
 *        for the next transmission call; or if the
 *        peer disconnected...); can be NULL
 * @param cont_cls closure for cont
 * @return number of bytes used (on the physical network, with overheads);
 *         -1 on hard errors (i.e. address invalid); 0 is a legal value
 *         and does NOT mean that the message was not transmitted (DV)
 */
static ssize_t
template_plugin_send (void *cls,
                  struct Session *session,
                  const char *msgbuf, size_t msgbuf_size,
                  unsigned int priority,
                  struct GNUNET_TIME_Relative to,
                  GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
{
  struct Plugin *plugin = cls;
  int bytes_sent = 0;

  GNUNET_assert (plugin != NULL);
  GNUNET_assert (session != NULL);

  /*  struct Plugin *plugin = cls; */
  return bytes_sent;
}



/**
 * Function that can be used to force the plugin to disconnect
 * from the given peer and cancel all previous transmissions
 * (and their continuationc).
 *
 * @param cls closure
 * @param target peer from which to disconnect
 */
static void
template_plugin_disconnect (void *cls, const struct GNUNET_PeerIdentity *target)
{
  // struct Plugin *plugin = cls;
  // FIXME
}


/**
 * Convert the transports address to a nice, human-readable
 * format.
 *
 * @param cls closure
 * @param type name of the transport that generated the address
 * @param addr one of the addresses of the host, NULL for the last address
 *        the specific address format depends on the transport
 * @param addrlen length of the address
 * @param numeric should (IP) addresses be displayed in numeric form?
 * @param timeout after how long should we give up?
 * @param asc function to call on each string
 * @param asc_cls closure for asc
 */
static void
template_plugin_address_pretty_printer (void *cls, const char *type,
                                        const void *addr, size_t addrlen,
                                        int numeric,
                                        struct GNUNET_TIME_Relative timeout,
                                        GNUNET_TRANSPORT_AddressStringCallback
                                        asc, void *asc_cls)
{
  asc (asc_cls, NULL);
}



/**
 * Another peer has suggested an address for this
 * peer and transport plugin.  Check that this could be a valid
 * address.  If so, consider adding it to the list
 * of addresses.
 *
 * @param cls closure
 * @param addr pointer to the address
 * @param addrlen length of addr
 * @return GNUNET_OK if this is a plausible address for this peer
 *         and transport
 */
static int
template_plugin_address_suggested (void *cls, const void *addr, size_t addrlen)
{
  /* struct Plugin *plugin = cls; */

  /* check if the address is plausible; if so,
   * add it to our list! */
  return GNUNET_OK;
}


/**
 * Function called for a quick conversion of the binary address to
 * a numeric address.  Note that the caller must not free the
 * address and that the next call to this function is allowed
 * to override the address again.
 *
 * @param cls closure
 * @param addr binary address
 * @param addrlen length of the address
 * @return string representing the same address
 */
static const char *
template_plugin_address_to_string (void *cls, const void *addr, size_t addrlen)
{
  GNUNET_break (0);
  return NULL;
}




/**
 * Entry point for the plugin.
 */
void *
gnunet_plugin_transport_template_init (void *cls)
{
  struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
  struct GNUNET_TRANSPORT_PluginFunctions *api;
  struct Plugin *plugin;

  plugin = GNUNET_malloc (sizeof (struct Plugin));
  plugin->env = env;
  api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
  api->cls = plugin;
  api->send = &template_plugin_send;
  api->disconnect = &template_plugin_disconnect;
  api->address_pretty_printer = &template_plugin_address_pretty_printer;
  api->check_address = &template_plugin_address_suggested;
  api->address_to_string = &template_plugin_address_to_string;
  return api;
}


/**
 * Exit point from the plugin.
 */
void *
gnunet_plugin_transport_template_done (void *cls)
{
  struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
  struct Plugin *plugin = api->cls;

  GNUNET_free (plugin);
  GNUNET_free (api);
  return NULL;
}

/* end of plugin_transport_template.c */