gnunet/src/fs/gnunet-service-fs.c

/*
     This file is part of GNUnet.
     (C) 2009, 2010, 2011 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 fs/gnunet-service-fs.c
 * @brief gnunet anonymity protocol implementation
 * @author Christian Grothoff
 *
 * To use:
 * - consider re-issue GSF_dht_lookup_ after non-DHT reply received 
 * - implement 'SUPPORT_DELAYS'
 *
 */
#include "platform.h"
#include <float.h>
#include "gnunet_constants.h"
#include "gnunet_core_service.h"
#include "gnunet_dht_service.h"
#include "gnunet_datastore_service.h"
#include "gnunet_load_lib.h"
#include "gnunet_peer_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_signatures.h"
#include "gnunet_statistics_service.h"
#include "gnunet_transport_service.h"
#include "gnunet_util_lib.h"
#include "gnunet-service-fs_cp.h"
#include "gnunet-service-fs_indexing.h"
#include "gnunet-service-fs_lc.h"
#include "gnunet-service-fs_pe.h"
#include "gnunet-service-fs_pr.h"
#include "gnunet-service-fs_push.h"
#include "gnunet-service-fs_put.h"
#include "fs.h"

/**
 * Size for the hash map for DHT requests from the FS
 * service.  Should be about the number of concurrent
 * DHT requests we plan to make.
 */
#define FS_DHT_HT_SIZE 1024


/**
 * How quickly do we age cover traffic?  At the given 
 * time interval, remaining cover traffic counters are
 * decremented by 1/16th.
 */
#define COVER_AGE_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)


/* ****************************** globals ****************************** */

/**
 * Our connection to the datastore.
 */
struct GNUNET_DATASTORE_Handle *GSF_dsh;

/**
 * Our configuration.
 */
const struct GNUNET_CONFIGURATION_Handle *GSF_cfg;

/**
 * Handle for reporting statistics.
 */
struct GNUNET_STATISTICS_Handle *GSF_stats;

/**
 * Handle for DHT operations.
 */
struct GNUNET_DHT_Handle *GSF_dht;

/**
 * How long do requests typically stay in the routing table?
 */
struct GNUNET_LOAD_Value *GSF_rt_entry_lifetime;

/**
 * Typical priorities we're seeing from other peers right now.  Since
 * most priorities will be zero, this value is the weighted average of
 * non-zero priorities seen "recently".  In order to ensure that new
 * values do not dramatically change the ratio, values are first
 * "capped" to a reasonable range (+N of the current value) and then
 * averaged into the existing value by a ratio of 1:N.  Hence
 * receiving the largest possible priority can still only raise our
 * "current_priorities" by at most 1.
 */
double GSF_current_priorities;

/**
 * How many query messages have we received 'recently' that 
 * have not yet been claimed as cover traffic?
 */
unsigned int GSF_cover_query_count;

/**
 * How many content messages have we received 'recently' that 
 * have not yet been claimed as cover traffic?
 */
unsigned int GSF_cover_content_count;

/**
 * Our block context.
 */
struct GNUNET_BLOCK_Context *GSF_block_ctx;

/**
 * Pointer to handle to the core service (points to NULL until we've
 * connected to it).
 */
struct GNUNET_CORE_Handle *GSF_core;

/**
 * Are we introducing randomized delays for better anonymity?
 */
int GSF_enable_randomized_delays;

/* ***************************** locals ******************************* */

/**
 * Configuration for block library.
 */
static struct GNUNET_CONFIGURATION_Handle *block_cfg;

/**
 * ID of our task that we use to age the cover counters.
 */
static GNUNET_SCHEDULER_TaskIdentifier cover_age_task;

/**
 * Datastore 'GET' load tracking.
 */
static struct GNUNET_LOAD_Value *datastore_get_load;

/**
 * Identity of this peer.
 */
static struct GNUNET_PeerIdentity my_id;

/**
 * Task that periodically ages our cover traffic statistics.
 *
 * @param cls unused closure
 * @param tc task context
 */
static void
age_cover_counters (void *cls,
		    const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  GSF_cover_content_count = (GSF_cover_content_count * 15) / 16;
  GSF_cover_query_count = (GSF_cover_query_count * 15) / 16;
  cover_age_task = GNUNET_SCHEDULER_add_delayed (COVER_AGE_FREQUENCY,
						 &age_cover_counters,
						 NULL);
}



/**
 * We've just now completed a datastore request.  Update our
 * datastore load calculations.
 *
 * @param start time when the datastore request was issued
 */
void
GSF_update_datastore_delay_ (struct GNUNET_TIME_Absolute start)
{
  struct GNUNET_TIME_Relative delay;

  delay = GNUNET_TIME_absolute_get_duration (start);
  GNUNET_LOAD_update (datastore_get_load,
		      delay.rel_value);
}


/**
 * Test if the DATABASE (GET) load on this peer is too high
 * to even consider processing the query at
 * all.  
 * 
 * @return GNUNET_YES if the load is too high to do anything (load high)
 *         GNUNET_NO to process normally (load normal)
 *         GNUNET_SYSERR to process for free (load low)
 */
int
GSF_test_get_load_too_high_ (uint32_t priority)
{
  double ld;

  ld = GNUNET_LOAD_get_load (datastore_get_load);
  if (ld < 1)
    return GNUNET_SYSERR;    
  if (ld <= priority)    
    return GNUNET_NO;    
  return GNUNET_YES;
}


/**
 * Handle P2P "PUT" message.
 *
 * @param cls closure, always NULL
 * @param other the other peer involved (sender or receiver, NULL
 *        for loopback messages where we are both sender and receiver)
 * @param message the actual message
 * @param atsi performance information
 * @return GNUNET_OK to keep the connection open,
 *         GNUNET_SYSERR to close it (signal serious error)
 */
static int
handle_p2p_put (void *cls,
		const struct GNUNET_PeerIdentity *other,
		const struct GNUNET_MessageHeader *message,
		const struct GNUNET_TRANSPORT_ATS_Information *atsi)
{
  struct GSF_ConnectedPeer *cp;

  cp = GSF_peer_get_ (other);
  if (NULL == cp)
    {
      GNUNET_break (0);
      return GNUNET_OK;
    }
  GSF_cover_content_count++;
  return GSF_handle_p2p_content_ (cp, message);
}


/**
 * We have a new request, consider forwarding it to the given
 * peer.
 *
 * @param cls the 'struct GSF_PendingRequest'
 * @param peer identity of the peer
 * @param cp handle to the connected peer record
 * @param ppd peer performance data
 */
static void
consider_request_for_forwarding (void *cls,
				 const struct GNUNET_PeerIdentity *peer,
				 struct GSF_ConnectedPeer *cp,
				 const struct GSF_PeerPerformanceData *ppd)
{
  struct GSF_PendingRequest *pr = cls;

  GSF_plan_add_ (cp, pr);
}


/**
 * Function to be called after we're done processing
 * replies from the local lookup.  If the result status
 * code indicates that there may be more replies, plan
 * forwarding the request.
 *
 * @param cls closure (NULL)
 * @param pr the pending request we were processing
 * @param result final datastore lookup result
 */
static void
consider_forwarding (void *cls,
		     struct GSF_PendingRequest *pr,
		     enum GNUNET_BLOCK_EvaluationResult result)
{
  if (GNUNET_BLOCK_EVALUATION_OK_LAST == result)
    return; /* we're done... */
  GSF_iterate_connected_peers_ (&consider_request_for_forwarding,
				pr);
}


/**
 * Handle P2P "GET" request.
 *
 * @param cls closure, always NULL
 * @param other the other peer involved (sender or receiver, NULL
 *        for loopback messages where we are both sender and receiver)
 * @param message the actual message
 * @param atsi performance information
 * @return GNUNET_OK to keep the connection open,
 *         GNUNET_SYSERR to close it (signal serious error)
 */
static int
handle_p2p_get (void *cls,
		const struct GNUNET_PeerIdentity *other,
		const struct GNUNET_MessageHeader *message,
		const struct GNUNET_TRANSPORT_ATS_Information *atsi)
{
  struct GSF_PendingRequest *pr;

  pr = GSF_handle_p2p_query_ (other, message);
  if (NULL == pr)
    return GNUNET_SYSERR;
  GSF_local_lookup_ (pr, 
		     &consider_forwarding,
		     NULL);
  return GNUNET_OK;
}


/**
 * We're done with the local lookup, now consider
 * P2P processing (depending on request options and
 * result status).  Also signal that we can now 
 * receive more request information from the client.
 *
 * @param cls the client doing the request ('struct GNUNET_SERVER_Client')
 * @param pr the pending request we were processing
 * @param result final datastore lookup result
 */
static void
start_p2p_processing (void *cls,
		      struct GSF_PendingRequest *pr,
		      enum GNUNET_BLOCK_EvaluationResult result)
{
  struct GNUNET_SERVER_Client *client = cls;
  struct GSF_PendingRequestData *prd;

  prd = GSF_pending_request_get_data_ (pr);
#if DEBUG_FS_CLIENT
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Finished database lookup for local request `%s' with result %d\n",
	      GNUNET_h2s (&prd->query),
	      result);
#endif
  GNUNET_SERVER_receive_done (client,
			      GNUNET_OK);
  if (GNUNET_BLOCK_EVALUATION_OK_LAST == result)
    return; /* we're done, 'pr' was already destroyed... */
  if (0 != (GSF_PRO_LOCAL_ONLY & prd->options) )
    {
      GSF_pending_request_cancel_ (pr, GNUNET_YES);
      return;
    }
  GSF_dht_lookup_ (pr);
  consider_forwarding (NULL, pr, result);
}


/**
 * Handle START_SEARCH-message (search request from client).
 *
 * @param cls closure
 * @param client identification of the client
 * @param message the actual message
 */
static void
handle_start_search (void *cls,
		     struct GNUNET_SERVER_Client *client,
		     const struct GNUNET_MessageHeader *message)
{
  struct GSF_PendingRequest *pr;

  pr = GSF_local_client_start_search_handler_ (client, message);
  if (NULL == pr)
    {
      /* GNUNET_SERVER_receive_done was already called! */
      return;
    }
  GSF_local_lookup_ (pr, 
		     &start_p2p_processing,
		     client);
}


/**
 * Task run during shutdown.
 *
 * @param cls unused
 * @param tc unused
 */
static void
shutdown_task (void *cls,
	       const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  if (NULL != GSF_core)
    {
      GNUNET_CORE_disconnect (GSF_core);
      GSF_core = NULL;
    }
  GSF_put_done_ ();
  GSF_push_done_ ();
  GSF_pending_request_done_ ();
  GSF_plan_done ();
  GSF_connected_peer_done_ ();
  GNUNET_DATASTORE_disconnect (GSF_dsh, GNUNET_NO);
  GSF_dsh = NULL;
  GNUNET_DHT_disconnect (GSF_dht);
  GSF_dht = NULL;
  GNUNET_BLOCK_context_destroy (GSF_block_ctx);
  GSF_block_ctx = NULL;
  GNUNET_CONFIGURATION_destroy (block_cfg);
  block_cfg = NULL;
  GNUNET_STATISTICS_destroy (GSF_stats, GNUNET_NO);
  GSF_stats = NULL;
  if (GNUNET_SCHEDULER_NO_TASK != cover_age_task)
    {
      GNUNET_SCHEDULER_cancel (cover_age_task);
      cover_age_task = GNUNET_SCHEDULER_NO_TASK;
    }
  GNUNET_FS_indexing_done ();
  GNUNET_LOAD_value_free (datastore_get_load);
  datastore_get_load = NULL;
  GNUNET_LOAD_value_free (GSF_rt_entry_lifetime);
  GSF_rt_entry_lifetime = NULL;
}


/**
 * Function called for each pending request whenever a new
 * peer connects, giving us a chance to decide about submitting
 * the existing request to the new peer.
 *
 * @param cls the 'struct GSF_ConnectedPeer' of the new peer
 * @param key query for the request
 * @param pr handle to the pending request
 * @return GNUNET_YES to continue to iterate
 */
static int
consider_peer_for_forwarding (void *cls,
			      const GNUNET_HashCode *key,
			      struct GSF_PendingRequest *pr)
{
  struct GSF_ConnectedPeer *cp = cls;
  
  GSF_plan_add_ (cp, pr);
  return GNUNET_YES;
}


/**
 * Method called whenever a given peer connects.
 *
 * @param cls closure, not used
 * @param peer peer identity this notification is about
 * @param atsi performance information
 */
static void 
peer_connect_handler (void *cls,
		      const struct GNUNET_PeerIdentity *peer,
		      const struct GNUNET_TRANSPORT_ATS_Information *atsi)
{
  struct GSF_ConnectedPeer *cp;

  if (0 == memcmp (&my_id, peer, sizeof (struct GNUNET_PeerIdentity)))
    return;
   cp = GSF_peer_connect_handler_ (peer, atsi);
  if (NULL == cp)
    return;
  GSF_iterate_pending_requests_ (&consider_peer_for_forwarding,
				 cp);
}


/**
 * Function called after GNUNET_CORE_connect has succeeded
 * (or failed for good).  Note that the private key of the
 * peer is intentionally not exposed here; if you need it,
 * your process should try to read the private key file
 * directly (which should work if you are authorized...).
 *
 * @param cls closure
 * @param server handle to the server, NULL if we failed
 * @param my_identity ID of this peer, NULL if we failed
 * @param publicKey public key of this peer, NULL if we failed
 */
static void
peer_init_handler (void *cls,
		   struct GNUNET_CORE_Handle * server,
		   const struct GNUNET_PeerIdentity *
		   my_identity,
		   const struct
		   GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *
		   publicKey)
{
  my_id = *my_identity;
}


/**
 * Process fs requests.
 *
 * @param server the initialized server
 * @param c configuration to use
 */
static int
main_init (struct GNUNET_SERVER_Handle *server,
	   const struct GNUNET_CONFIGURATION_Handle *c)
{
  static const struct GNUNET_CORE_MessageHandler p2p_handlers[] =
    {
      { &handle_p2p_get, 
	GNUNET_MESSAGE_TYPE_FS_GET, 0 },
      { &handle_p2p_put, 
	GNUNET_MESSAGE_TYPE_FS_PUT, 0 },
      { &GSF_handle_p2p_migration_stop_, 
	GNUNET_MESSAGE_TYPE_FS_MIGRATION_STOP,
	sizeof (struct MigrationStopMessage) },
      { NULL, 0, 0 }
    };
  static const struct GNUNET_SERVER_MessageHandler handlers[] = {
    {&GNUNET_FS_handle_index_start, NULL, 
     GNUNET_MESSAGE_TYPE_FS_INDEX_START, 0},
    {&GNUNET_FS_handle_index_list_get, NULL, 
     GNUNET_MESSAGE_TYPE_FS_INDEX_LIST_GET, sizeof(struct GNUNET_MessageHeader) },
    {&GNUNET_FS_handle_unindex, NULL, GNUNET_MESSAGE_TYPE_FS_UNINDEX, 
     sizeof (struct UnindexMessage) },
    {&handle_start_search, NULL, GNUNET_MESSAGE_TYPE_FS_START_SEARCH, 
     0 },
    {NULL, NULL, 0, 0}
  };

  GSF_core = GNUNET_CORE_connect (GSF_cfg,
				  2, /* larger? */
				  NULL,
				  &peer_init_handler,
				  &peer_connect_handler,
				  &GSF_peer_disconnect_handler_,
				  &GSF_peer_status_handler_,
				  NULL, GNUNET_NO,
				  NULL, GNUNET_NO,
				  p2p_handlers);
  if (NULL == GSF_core)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		  _("Failed to connect to `%s' service.\n"),
		  "core");
      return GNUNET_SYSERR;
    }
  GNUNET_SERVER_disconnect_notify (server, 
				   &GSF_client_disconnect_handler_,
				   NULL);
  GNUNET_SERVER_add_handlers (server, handlers);
  cover_age_task = GNUNET_SCHEDULER_add_delayed (COVER_AGE_FREQUENCY,
						 &age_cover_counters,
						 NULL);
  datastore_get_load = GNUNET_LOAD_value_init (DATASTORE_LOAD_AUTODECLINE);
  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
				&shutdown_task,
				NULL);
  return GNUNET_OK;
}


/**
 * Process fs requests.
 *
 * @param cls closure
 * @param server the initialized server
 * @param cfg configuration to use
 */
static void
run (void *cls,
     struct GNUNET_SERVER_Handle *server,
     const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  GSF_cfg = cfg;
  GSF_enable_randomized_delays = GNUNET_CONFIGURATION_get_value_yesno (cfg, "fs", "DELAY");
  GSF_dsh = GNUNET_DATASTORE_connect (cfg);
  if (NULL == GSF_dsh)
    {
      GNUNET_SCHEDULER_shutdown ();
      return;
    }
  GSF_rt_entry_lifetime = GNUNET_LOAD_value_init (GNUNET_TIME_UNIT_FOREVER_REL);
  GSF_stats = GNUNET_STATISTICS_create ("fs", cfg);
  block_cfg = GNUNET_CONFIGURATION_create ();
  GNUNET_CONFIGURATION_set_value_string (block_cfg,
					 "block",
					 "PLUGINS",
					 "fs");
  GSF_block_ctx = GNUNET_BLOCK_context_create (block_cfg);
  GNUNET_assert (NULL != GSF_block_ctx);
  GSF_dht = GNUNET_DHT_connect (cfg,
				FS_DHT_HT_SIZE);
  GSF_plan_init ();
  GSF_pending_request_init_ ();
  GSF_connected_peer_init_ ();
  GSF_push_init_ ();
  GSF_put_init_ ();
  if ( (GNUNET_OK != GNUNET_FS_indexing_init (cfg, GSF_dsh)) ||
       
       (GNUNET_OK != main_init (server, cfg)) )
    {    
      GNUNET_SCHEDULER_shutdown ();
      shutdown_task (NULL, NULL);
      return;   
    }
}


/**
 * The main function for the fs service.
 *
 * @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)
{
  return (GNUNET_OK ==
          GNUNET_SERVICE_run (argc,
                              argv,
                              "fs",
			      GNUNET_SERVICE_OPTION_NONE,
			      &run, NULL)) ? 0 : 1;
}

/* end of gnunet-service-fs.c */