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path: root/src/dv/plugin_transport_dv.c
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/*
     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 dv/plugin_transport_dv.c
 * @brief DV transport service, takes incoming DV requests and deals with
 * the DV service
 * @author Nathan Evans
 * @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_dv_service.h"
#include "gnunet_transport_service.h"
#include "gnunet_transport_plugin.h"
#include "dv.h"

#define DEBUG_TEMPLATE GNUNET_EXTRA_LOGGING

/**
 * 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;

  /**
   * Our server.
   */
  //struct GNUNET_SERVER_Handle *server;

  /*
   * Handle to the running service.
   */
  //struct GNUNET_SERVICE_Context *service;

  /**
   * Copy of the handler array where the closures are
   * set to this struct's instance.
   */
  struct GNUNET_SERVER_MessageHandler *handlers;

  /**
   * Handle to the DV service
   */
  struct GNUNET_DV_Handle *dv_handle;

};

/**
 * Handler for messages received from the DV service.
 */
void
handle_dv_message_received (void *cls, struct GNUNET_PeerIdentity *sender,
                            char *msg, size_t msg_len, uint32_t distance,
                            char *sender_address, size_t sender_address_len)
{
  struct Plugin *plugin = cls;

#if DEBUG_DV_MESSAGES
  char *my_id;

  my_id = GNUNET_strdup (GNUNET_i2s (plugin->env->my_identity));
  GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "plugin_transport_dv",
                   _("%s Received message from %s of type %d, distance %u!\n"),
                   my_id, GNUNET_i2s (sender),
                   ntohs (((struct GNUNET_MessageHeader *) msg)->type),
                   distance);
  if (sender_address_len == (2 * sizeof(struct GNUNET_PeerIdentity)))
    {
      GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "plugin_transport_dv", "Parsed sender address: %s:%s\n", GNUNET_i2s((struct GNUNET_PeerIdentity *)sender_address), GNUNET_h2s(&((struct GNUNET_PeerIdentity *)&sender_address[sizeof(struct GNUNET_PeerIdentity)])->hashPubKey));
    }

  GNUNET_free_non_null (my_id);
#endif
  struct GNUNET_ATS_Information ats[1];

  ats[0].type = htonl (GNUNET_ATS_QUALITY_NET_DISTANCE);
  ats[0].value = htonl (distance);

  plugin->env->receive (plugin->env->cls, sender,
                        (struct GNUNET_MessageHeader *) msg,
                        (const struct GNUNET_ATS_Information *) &ats, 1, NULL,
                        sender_address, sender_address_len);

}


/* Question: how does the transport service learn of a newly connected (gossipped about)
 * DV peer?  Should the plugin (here) create a HELLO for that peer and send it along,
 * or should the DV service create a HELLO and send it to us via the other part?
 */

/**
 * Function that can be used by the transport service to transmit
 * a message using the plugin.
 *
 * @param cls closure
 * @param target who should receive this message
 * @param priority how important is the message
 * @param msgbuf the message to transmit
 * @param msgbuf_size number of bytes in 'msgbuf'
 * @param timeout when should we time out
 * @param session the session used
 * @param addr the address to use (can be NULL if the plugin
 *                is "on its own" (i.e. re-use existing TCP connection))
 * @param addrlen length of the address in bytes
 * @param force_address GNUNET_YES if the plugin MUST use the given address,
 *                otherwise the plugin may use other addresses or
 *                existing connections (if available)
 * @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...)
 * @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
dv_plugin_send (void *cls, const struct GNUNET_PeerIdentity *target,
                const char *msgbuf, size_t msgbuf_size, unsigned int priority,
                struct GNUNET_TIME_Relative timeout, struct Session *session,
                const void *addr, size_t addrlen, int force_address,
                GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
{
  int ret = 0;
  struct Plugin *plugin = cls;

  ret =
      GNUNET_DV_send (plugin->dv_handle, target, msgbuf, msgbuf_size, priority,
                      timeout, addr, addrlen, cont, cont_cls);
  return ret;
}



/**
 * Function that can be used to force the plugin to disconnect
 * from the given peer and cancel all previous transmissions
 * (and their continuations).
 *
 * @param cls closure
 * @param target peer from which to disconnect
 */
static void
dv_plugin_disconnect (void *cls, const struct GNUNET_PeerIdentity *target)
{
  // struct Plugin *plugin = cls;
  // TODO: Add message type to send to dv service to "disconnect" a peer
}


/**
 * 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
dv_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)
{
  char *dest_peer;
  char *via_peer;
  char *print_string;
  char *addr_buf = (char *) addr;

  if (addrlen != sizeof (struct GNUNET_PeerIdentity) * 2)
  {
    asc (asc_cls, NULL);
  }
  else
  {
    dest_peer =
        GNUNET_strdup (GNUNET_i2s ((struct GNUNET_PeerIdentity *) addr));
    via_peer =
        GNUNET_strdup (GNUNET_i2s
                       ((struct GNUNET_PeerIdentity *)
                        &addr_buf[sizeof (struct GNUNET_PeerIdentity)]));
    GNUNET_asprintf (&print_string, "DV Peer `%s' via peer`%s'", dest_peer,
                     via_peer);
    asc (asc_cls, print_string);
    asc (asc_cls, NULL);
    GNUNET_free (via_peer);
    GNUNET_free (dest_peer);
    GNUNET_free (print_string);
  }
}

/**
 * Convert the DV address to a pretty string.
 *
 * @param cls closure
 * @param addr the (hopefully) DV address
 * @param addrlen the length of the address
 *
 * @return string representing the DV address
 */
static const char *
address_to_string (void *cls, const void *addr, size_t addrlen)
{
  static char return_buffer[2 * 4 + 2]; // Two four character peer identity prefixes a ':' and '\0'

  struct GNUNET_CRYPTO_HashAsciiEncoded peer_hash;
  struct GNUNET_CRYPTO_HashAsciiEncoded via_hash;
  struct GNUNET_PeerIdentity *peer;
  struct GNUNET_PeerIdentity *via;
  char *addr_buf = (char *) addr;

  if (addrlen == (2 * sizeof (struct GNUNET_PeerIdentity)))
  {
    peer = (struct GNUNET_PeerIdentity *) addr_buf;
    via =
        (struct GNUNET_PeerIdentity *)
        &addr_buf[sizeof (struct GNUNET_PeerIdentity)];

    GNUNET_CRYPTO_hash_to_enc (&peer->hashPubKey, &peer_hash);
    peer_hash.encoding[4] = '\0';
    GNUNET_CRYPTO_hash_to_enc (&via->hashPubKey, &via_hash);
    via_hash.encoding[4] = '\0';
    GNUNET_snprintf (return_buffer, sizeof (return_buffer), "%s:%s", &peer_hash,
                     &via_hash);
  }
  else
    return NULL;

  return return_buffer;
}

/**
 * Another peer has suggested an address for this peer and transport
 * plugin.  Check that this could be a valid address.  This function
 * is not expected to 'validate' the address in the sense of trying to
 * connect to it but simply to see if the binary format is technically
 * legal for establishing a connection to this peer (and make sure that
 * the address really corresponds to our network connection/settings
 * and not some potential man-in-the-middle).
 *
 * @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, GNUNET_SYSERR if not
 *
 */
static int
dv_plugin_check_address (void *cls, const void *addr, size_t addrlen)
{
  struct Plugin *plugin = cls;

  /* Verify that the first peer of this address matches our peer id! */
  if ((addrlen != (2 * sizeof (struct GNUNET_PeerIdentity))) ||
      (0 !=
       memcmp (addr, plugin->env->my_identity,
               sizeof (struct GNUNET_PeerIdentity))))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "%s: Address not correct size or identity doesn't match ours!\n",
                GNUNET_i2s (plugin->env->my_identity));
    if (addrlen == (2 * sizeof (struct GNUNET_PeerIdentity)))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Peer in address is %s\n",
                  GNUNET_i2s (addr));
    }
    return GNUNET_SYSERR;
  }

  return GNUNET_OK;
}


/**
 * Entry point for the plugin.
 */
void *
libgnunet_plugin_transport_dv_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;

  plugin->dv_handle =
      GNUNET_DV_connect (env->cfg, &handle_dv_message_received, plugin);

  if (plugin->dv_handle == NULL)
  {
    GNUNET_free (plugin);
    return NULL;
  }

  api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
  api->cls = plugin;
  api->send = &dv_plugin_send;
  api->disconnect = &dv_plugin_disconnect;
  api->address_pretty_printer = &dv_plugin_address_pretty_printer;
  api->check_address = &dv_plugin_check_address;
  api->address_to_string = &address_to_string;
  return api;
}


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

  if (plugin->dv_handle != NULL)
    GNUNET_DV_disconnect (plugin->dv_handle);

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

/* end of plugin_transport_template.c */