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22 * @file dht/gnunet-service-xdht_routing.c
23 * @brief GNUnet DHT tracking of requests for routing replies
24 * @author Supriti Singh
27 #include "gnunet-service-xdht_neighbours.h"
28 #include "gnunet-service-xdht_routing.h"
29 #include "gnunet-service-xdht.h"
33 * FIXME: Check if its better to store pointer to friend rather than storing
34 * peer identity next_hop or prev_hop.
35 * keep entries in destnation and source peer also. so when we send the trail
36 * teardown message then we don't know the source but if source gets the message
37 * then it shold remove that trail id from its finger table. But how does
38 * source know what is the desination finger ? It will whenevr contact a trail
39 * will do a lookup in routing table and if no trail id present the remove
40 * that trail of the finger and if only one trail then remove the finger.
41 * because of this use case of trail teardown I think trail compression
42 * and trail teardown should not be merged.
43 * 2. store a pointer to friendInfo in place o peer identity.
46 * Maximum number of entries in routing table.
48 #define ROUTING_TABLE_THRESHOLD 64
51 * FIXME: Store friend pointer instead of peer identifier.
52 * Routing table entry .
57 * Global Unique identifier of the trail.
59 struct GNUNET_HashCode trail_id;
62 * The peer to which this request should be passed to.
64 struct GNUNET_PeerIdentity next_hop;
67 * Peer just before next hop in the trail.
69 struct GNUNET_PeerIdentity prev_hop;
73 * Routing table of the peer
75 static struct GNUNET_CONTAINER_MultiHashMap *routing_table;
78 * Update the prev. hop of the trail. Call made by trail compression where
79 * if you are the first friend now in the trail then you need to update
82 * @return #GNUNET_OK success
83 * #GNUNET_SYSERR in case no matching entry found in routing table.
86 GDS_ROUTING_update_trail_prev_hop (const struct GNUNET_HashCode trail_id,
87 struct GNUNET_PeerIdentity prev_hop)
89 struct RoutingTrail *trail;
91 trail = GNUNET_CONTAINER_multihashmap_get (routing_table, &trail_id);
96 trail->prev_hop = prev_hop;
101 * Update the next hop of the trail. Call made by trail compression where
102 * if you are source of the trail and now you have a new first friend, then
103 * you should update the trail.
105 * @return #GNUNET_OK success
106 * #GNUNET_SYSERR in case no matching entry found in routing table.
109 GDS_ROUTING_update_trail_next_hop (const struct GNUNET_HashCode trail_id,
110 struct GNUNET_PeerIdentity next_hop)
112 struct RoutingTrail *trail;
114 trail = GNUNET_CONTAINER_multihashmap_get (routing_table, &trail_id);
118 return GNUNET_SYSERR;
120 trail->next_hop = next_hop;
125 * Get the next hop for trail corresponding to trail_id
126 * @param trail_id Trail id to be searched.
127 * @return Next_hop if found
128 * NULL If next hop not found.
130 struct GNUNET_PeerIdentity *
131 GDS_ROUTING_get_next_hop (const struct GNUNET_HashCode trail_id,
132 enum GDS_ROUTING_trail_direction trail_direction)
134 struct RoutingTrail *trail;
136 trail = GNUNET_CONTAINER_multihashmap_get (routing_table, &trail_id);
140 /* If a friend got disconnected and we removed all the entry from the
141 routing table, then trail will be deleted and my identity will not know
142 and when it tries to reach to that finger it fails. thats why
143 assertion always fails in*/
146 switch (trail_direction)
148 case GDS_ROUTING_SRC_TO_DEST:
149 return &(trail->next_hop);
150 case GDS_ROUTING_DEST_TO_SRC:
151 return &(trail->prev_hop);
158 * Remove trail with trail_id
159 * @param trail_id Trail id to be removed
160 * @return #GNUNET_YES success
161 * #GNUNET_NO if entry not found.
164 GDS_ROUTING_remove_trail (const struct GNUNET_HashCode remove_trail_id)
166 struct RoutingTrail *remove_entry;
168 remove_entry = GNUNET_CONTAINER_multihashmap_get (routing_table, &remove_trail_id);
170 if (NULL == remove_entry)
173 if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (routing_table,
177 GNUNET_free (remove_entry);
185 * Iterate over routing table and remove entries with value as part of any trail.
188 * @param key current public key
189 * @param value value in the hash map
190 * @return #GNUNET_YES if we should continue to iterate,
193 static int remove_matching_trails (void *cls,
194 const struct GNUNET_HashCode *key,
197 struct RoutingTrail *remove_trail = value;
198 struct GNUNET_PeerIdentity *disconnected_peer = cls;
199 struct GNUNET_HashCode trail_id = *key;
200 struct GNUNET_PeerIdentity my_identity;
202 /* If disconnected_peer is next_hop, then send a trail teardown message through
203 * prev_hop in direction from destination to source. */
204 if (0 == GNUNET_CRYPTO_cmp_peer_identity (&remove_trail->next_hop,
207 my_identity = GDS_NEIGHBOURS_get_my_id ();
208 if (0 != GNUNET_CRYPTO_cmp_peer_identity (&my_identity,
209 &remove_trail->prev_hop))
211 GDS_NEIGHBOURS_send_trail_teardown (trail_id,
212 GDS_ROUTING_DEST_TO_SRC,
213 remove_trail->prev_hop);
217 /* If disconnected_peer is prev_hop, then send a trail teardown through
218 * next_hop in direction from Source to Destination. */
219 if (0 == GNUNET_CRYPTO_cmp_peer_identity (&remove_trail->prev_hop,
222 my_identity = GDS_NEIGHBOURS_get_my_id ();
223 if (0 != GNUNET_CRYPTO_cmp_peer_identity (&my_identity,
224 &remove_trail->next_hop))
226 GDS_NEIGHBOURS_send_trail_teardown (trail_id,
227 GDS_ROUTING_SRC_TO_DEST,
228 remove_trail->next_hop);
232 GNUNET_assert (GNUNET_YES ==
233 GNUNET_CONTAINER_multihashmap_remove (routing_table,
236 GNUNET_free (remove_trail);
243 * Remove after using.
246 GDS_ROUTING_test_print (void)
248 struct GNUNET_CONTAINER_MultiHashMapIterator *iter;
249 struct RoutingTrail *trail;
250 struct GNUNET_PeerIdentity print_peer;
251 struct GNUNET_HashCode key_ret;
254 FPRINTF (stderr,_("\nSUPU ***PRINTING ROUTING TABLE *****"));
255 iter =GNUNET_CONTAINER_multihashmap_iterator_create (routing_table);
256 for (i = 0; i < GNUNET_CONTAINER_multihashmap_size(routing_table); i++)
258 if(GNUNET_YES == GNUNET_CONTAINER_multihashmap_iterator_next (iter,
260 (const void **)&trail))
262 FPRINTF (stderr,_("\nSUPU %s, %s, %d, trail->trail_id = %s"),
263 __FILE__, __func__,__LINE__, GNUNET_h2s(&trail->trail_id));
264 memcpy (&print_peer, &trail->next_hop, sizeof (struct GNUNET_PeerIdentity));
265 FPRINTF (stderr,_("\nSUPU %s, %s, %d, trail->next_hop = %s"),
266 __FILE__, __func__,__LINE__, GNUNET_i2s(&print_peer));
267 memcpy (&print_peer, &trail->prev_hop, sizeof (struct GNUNET_PeerIdentity));
268 FPRINTF (stderr,_("\nSUPU %s, %s, %d, trail->prev_hop = %s"),
269 __FILE__, __func__,__LINE__, GNUNET_i2s(&print_peer));
276 * Remove every trail where peer is either next_hop or prev_hop. Also send a
277 * trail teardown message in direction of hop which is not disconnected.
278 * @param peer Peer identity. Trail containing this peer should be removed.
281 GDS_ROUTING_remove_trail_by_peer (const struct GNUNET_PeerIdentity *peer)
286 /* No entries in my routing table. */
287 if (0 == GNUNET_CONTAINER_multihashmap_size(routing_table))
290 ret = GNUNET_CONTAINER_multihashmap_iterate (routing_table,
291 &remove_matching_trails,
298 * Add a new entry in routing table
299 * @param new_trail_id
302 * @return #GNUNET_OK success
303 * #GNUNET_SYSERR in case new_trail_id already exists in the network
304 * but with different prev_hop/next_hop
307 GDS_ROUTING_add (struct GNUNET_HashCode new_trail_id,
308 struct GNUNET_PeerIdentity prev_hop,
309 struct GNUNET_PeerIdentity next_hop)
311 struct RoutingTrail *new_entry;
313 new_entry = GNUNET_new (struct RoutingTrail);
314 new_entry->trail_id = new_trail_id;
315 new_entry->next_hop = next_hop;
316 new_entry->prev_hop = prev_hop;
318 return GNUNET_CONTAINER_multihashmap_put (routing_table,
319 &new_trail_id, new_entry,
320 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
325 * Check if the size of routing table has crossed ROUTING_TABLE_THRESHOLD.
326 * It means that I don't have any more space in my routing table and I can not
327 * be part of any more trails till there is free space in my routing table.
328 * @return #GNUNET_YES, if threshold crossed else #GNUNET_NO.
331 GDS_ROUTING_threshold_reached (void)
333 return (GNUNET_CONTAINER_multihashmap_size(routing_table) >
334 ROUTING_TABLE_THRESHOLD) ? GNUNET_YES:GNUNET_NO;
339 * Initialize routing subsystem.
342 GDS_ROUTING_init (void)
344 routing_table = GNUNET_CONTAINER_multihashmap_create (ROUTING_TABLE_THRESHOLD * 4 / 3,
350 * Shutdown routing subsystem.
353 GDS_ROUTING_done (void)
355 GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap_size (routing_table));
356 GNUNET_CONTAINER_multihashmap_destroy (routing_table);
359 /* end of gnunet-service-xdht_routing.c */