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- /*
- This file is part of GNUnet.
- (C) 2011 - 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 dht/gnunet-service-xdht_routing.c
- * @brief GNUnet DHT tracking of requests for routing replies
- * @author Supriti Singh
- */
- #include "platform.h"
- #include "gnunet-service-xdht_neighbours.h"
- #include "gnunet-service-xdht_routing.h"
- #include "gnunet-service-xdht.h"
- /**
- * FIXME: Check if its better to store pointer to friend rather than storing
- * peer identity next_hop or prev_hop.
- * keep entries in destnation and source peer also. so when we send the trail
- * teardown message then we don't know the source but if source gets the message
- * then it shold remove that trail id from its finger table. But how does
- * source know what is the desination finger ? It will whenevr contact a trail
- * will do a lookup in routing table and if no trail id present the remove
- * that trail of the finger and if only one trail then remove the finger.
- * because of this use case of trail teardown I think trail compression
- * and trail teardown should not be merged.
- * 2. store a pointer to friendInfo in place o peer identity.
- */
- /**
- * Maximum number of entries in routing table.
- */
- #define ROUTING_TABLE_THRESHOLD 80000
- /**
- * FIXME: Store friend pointer instead of peer identifier.
- * Routing table entry .
- */
- struct RoutingTrail
- {
- /**
- * Global Unique identifier of the trail.
- */
- struct GNUNET_HashCode trail_id;
- /**
- * The peer to which this request should be passed to.
- */
- struct GNUNET_PeerIdentity next_hop;
- /**
- * Peer just before next hop in the trail.
- */
- struct GNUNET_PeerIdentity prev_hop;
- };
- /**
- * Routing table of the peer
- */
- static struct GNUNET_CONTAINER_MultiHashMap *routing_table;
- /**
- * Update the prev. hop of the trail. Call made by trail compression where
- * if you are the first friend now in the trail then you need to update
- * your prev. hop.
- * @param trail_id
- * @return #GNUNET_OK success
- * #GNUNET_SYSERR in case no matching entry found in routing table.
- */
- int
- GDS_ROUTING_update_trail_prev_hop (const struct GNUNET_HashCode trail_id,
- struct GNUNET_PeerIdentity prev_hop)
- {
- struct RoutingTrail *trail;
- trail = GNUNET_CONTAINER_multihashmap_get (routing_table, &trail_id);
- if (NULL == trail)
- return GNUNET_SYSERR;
- trail->prev_hop = prev_hop;
- return GNUNET_OK;
- }
- /**
- * Update the next hop of the trail. Call made by trail compression where
- * if you are source of the trail and now you have a new first friend, then
- * you should update the trail.
- * @param trail_id
- * @return #GNUNET_OK success
- * #GNUNET_SYSERR in case no matching entry found in routing table.
- */
- int
- GDS_ROUTING_update_trail_next_hop (const struct GNUNET_HashCode trail_id,
- struct GNUNET_PeerIdentity next_hop)
- {
- struct RoutingTrail *trail;
- trail = GNUNET_CONTAINER_multihashmap_get (routing_table, &trail_id);
- if (NULL == trail)
- return GNUNET_SYSERR;
- trail->next_hop = next_hop;
- return GNUNET_OK;
- }
- /**
- * Get the next hop for trail corresponding to trail_id
- * @param trail_id Trail id to be searched.
- * @return Next_hop if found
- * NULL If next hop not found.
- */
- struct GNUNET_PeerIdentity *
- GDS_ROUTING_get_next_hop (const struct GNUNET_HashCode trail_id,
- enum GDS_ROUTING_trail_direction trail_direction)
- {
- struct RoutingTrail *trail;
- trail = GNUNET_CONTAINER_multihashmap_get (routing_table, &trail_id);
- if (NULL == trail)
- {
- /* If a friend got disconnected and we removed all the entry from the
- routing table, then trail will be deleted and my identity will not know
- and when it tries to reach to that finger it fails. thats why
- assertion always fails in*/
- return NULL;
- }
- switch (trail_direction)
- {
- case GDS_ROUTING_SRC_TO_DEST:
- return &(trail->next_hop);
- case GDS_ROUTING_DEST_TO_SRC:
- return &(trail->prev_hop);
- }
- return NULL;
- }
- /**
- * Remove trail with trail_id
- * @param trail_id Trail id to be removed
- * @return #GNUNET_YES success
- * #GNUNET_NO if entry not found.
- */
- int
- GDS_ROUTING_remove_trail (const struct GNUNET_HashCode remove_trail_id)
- {
- struct RoutingTrail *remove_entry;
- remove_entry = GNUNET_CONTAINER_multihashmap_get (routing_table, &remove_trail_id);
- if (NULL == remove_entry)
- return GNUNET_NO;
- if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (routing_table,
- &remove_trail_id,
- remove_entry))
- {
- GNUNET_free (remove_entry);
- return GNUNET_YES;
- }
- return GNUNET_NO;
- }
- /**
- * Iterate over routing table and remove entries with value as part of any trail.
- *
- * @param cls closure
- * @param key current public key
- * @param value value in the hash map
- * @return #GNUNET_YES if we should continue to iterate,
- * #GNUNET_NO if not.
- */
- static int remove_matching_trails (void *cls,
- const struct GNUNET_HashCode *key,
- void *value)
- {
- struct RoutingTrail *remove_trail = value;
- struct GNUNET_PeerIdentity *disconnected_peer = cls;
- struct GNUNET_HashCode trail_id = *key;
- struct GNUNET_PeerIdentity my_identity;
- /* If disconnected_peer is next_hop, then send a trail teardown message through
- * prev_hop in direction from destination to source. */
- if (0 == GNUNET_CRYPTO_cmp_peer_identity (&remove_trail->next_hop,
- disconnected_peer))
- {
- my_identity = GDS_NEIGHBOURS_get_my_id ();
- if (0 != GNUNET_CRYPTO_cmp_peer_identity (&my_identity,
- &remove_trail->prev_hop))
- {
- GDS_NEIGHBOURS_send_trail_teardown (&trail_id,
- GDS_ROUTING_DEST_TO_SRC,
- &remove_trail->prev_hop);
- }
- }
- /* If disconnected_peer is prev_hop, then send a trail teardown through
- * next_hop in direction from Source to Destination. */
- if (0 == GNUNET_CRYPTO_cmp_peer_identity (&remove_trail->prev_hop,
- disconnected_peer))
- {
- my_identity = GDS_NEIGHBOURS_get_my_id ();
- if (0 != GNUNET_CRYPTO_cmp_peer_identity (&my_identity,
- &remove_trail->next_hop))
- {
- GDS_NEIGHBOURS_send_trail_teardown (&trail_id,
- GDS_ROUTING_SRC_TO_DEST,
- &remove_trail->next_hop);
- }
- }
- GNUNET_assert (GNUNET_YES ==
- GNUNET_CONTAINER_multihashmap_remove (routing_table,
- &trail_id,
- remove_trail));
- GNUNET_free (remove_trail);
- return GNUNET_YES;
- }
- #if 0
- /**
- * TEST FUNCTION
- * Remove after using.
- */
- void
- GDS_ROUTING_test_print (void)
- {
- struct GNUNET_CONTAINER_MultiHashMapIterator *iter;
- struct RoutingTrail *trail;
- struct GNUNET_PeerIdentity print_peer;
- struct GNUNET_HashCode key_ret;
- int i;
- struct GNUNET_PeerIdentity my_identity = GDS_NEIGHBOURS_get_my_id();
- print_peer = my_identity;
- FPRINTF (stderr,_("\nSUPU ***PRINTING ROUTING TABLE ***** of =%s"),GNUNET_i2s(&print_peer));
- iter =GNUNET_CONTAINER_multihashmap_iterator_create (routing_table);
- for (i = 0; i < GNUNET_CONTAINER_multihashmap_size(routing_table); i++)
- {
- if(GNUNET_YES == GNUNET_CONTAINER_multihashmap_iterator_next (iter,
- &key_ret,
- (const void **)&trail))
- {
- FPRINTF (stderr,_("\nSUPU %s, %s, %d, trail->trail_id = %s"),
- __FILE__, __func__,__LINE__, GNUNET_h2s(&trail->trail_id));
- memcpy (&print_peer, &trail->next_hop, sizeof (struct GNUNET_PeerIdentity));
- FPRINTF (stderr,_("\nSUPU %s, %s, %d, trail->next_hop = %s"),
- __FILE__, __func__,__LINE__, GNUNET_i2s(&print_peer));
- memcpy (&print_peer, &trail->prev_hop, sizeof (struct GNUNET_PeerIdentity));
- FPRINTF (stderr,_("\nSUPU %s, %s, %d, trail->prev_hop = %s"),
- __FILE__, __func__,__LINE__, GNUNET_i2s(&print_peer));
- }
- }
- }
- #endif
- /**
- * Remove every trail where peer is either next_hop or prev_hop. Also send a
- * trail teardown message in direction of hop which is not disconnected.
- * @param peer Peer identity. Trail containing this peer should be removed.
- */
- int
- GDS_ROUTING_remove_trail_by_peer (const struct GNUNET_PeerIdentity *peer)
- {
- int ret;
- /* No entries in my routing table. */
- if (0 == GNUNET_CONTAINER_multihashmap_size(routing_table))
- return GNUNET_YES;
- ret = GNUNET_CONTAINER_multihashmap_iterate (routing_table,
- &remove_matching_trails,
- (void *)peer);
- return ret;
- }
- /**
- * Add a new entry in routing table
- * @param new_trail_id
- * @param prev_hop
- * @param next_hop
- * @return #GNUNET_OK success
- * #GNUNET_SYSERR in case new_trail_id already exists in the network
- * but with different prev_hop/next_hop
- */
- int
- GDS_ROUTING_add (struct GNUNET_HashCode new_trail_id,
- struct GNUNET_PeerIdentity prev_hop,
- struct GNUNET_PeerIdentity next_hop)
- {
- struct RoutingTrail *new_entry;
- new_entry = GNUNET_new (struct RoutingTrail);
- new_entry->trail_id = new_trail_id;
- new_entry->next_hop = next_hop;
- new_entry->prev_hop = prev_hop;
- return GNUNET_CONTAINER_multihashmap_put (routing_table,
- &new_trail_id, new_entry,
- GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
- }
- /**
- * Check if the size of routing table has crossed ROUTING_TABLE_THRESHOLD.
- * It means that I don't have any more space in my routing table and I can not
- * be part of any more trails till there is free space in my routing table.
- * @return #GNUNET_YES, if threshold crossed else #GNUNET_NO.
- */
- int
- GDS_ROUTING_threshold_reached (void)
- {
- return (GNUNET_CONTAINER_multihashmap_size(routing_table) >
- ROUTING_TABLE_THRESHOLD) ? GNUNET_YES:GNUNET_NO;
- }
- /**
- * Initialize routing subsystem.
- */
- void
- GDS_ROUTING_init (void)
- {
- routing_table = GNUNET_CONTAINER_multihashmap_create (ROUTING_TABLE_THRESHOLD * 4 / 3,
- GNUNET_NO);
- }
- /**
- * Shutdown routing subsystem.
- */
- void
- GDS_ROUTING_done (void)
- {
- GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap_size (routing_table));
- GNUNET_CONTAINER_multihashmap_destroy (routing_table);
- }
- /* end of gnunet-service-xdht_routing.c */
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