2 This file is part of GNUnet.
3 (C) 2001 - 2013 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
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17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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22 * @file cadet/cadet_path.c
23 * @brief Path handling functions
24 * @author Bartlomiej Polot
28 #include "cadet_path.h"
29 #include "gnunet-service-cadet_peer.h"
31 #define LOG(level, ...) GNUNET_log_from (level,"cadet-pth",__VA_ARGS__)
35 * @brief Destroy a path after some time has past.
37 * If the path is returned from DHT again after a while, try again.
39 * Removes the path from the peer (except for direct paths).
41 * @param cls Closure (path to destroy).
42 * @param tc Task context.
45 path_destroy_delayed (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
47 struct CadetPeerPath *path = cls;
48 struct CadetPeer *peer;
50 LOG (GNUNET_ERROR_TYPE_INFO, "Destroy delayed %p (%u)\n", path, path->length);
51 path->path_delete = NULL;
52 peer = GCP_get_short (path->peers[path->length - 1]);
54 GCP_remove_path (peer, path);
63 * @param length How many hops will the path have.
65 * @return A newly allocated path with a peer array of the specified length.
67 struct CadetPeerPath *
68 path_new (unsigned int length)
70 struct CadetPeerPath *p;
72 p = GNUNET_new (struct CadetPeerPath);
76 p->peers = GNUNET_malloc (length * sizeof (GNUNET_PEER_Id));
85 * @param path the path to invert
88 path_invert (struct CadetPeerPath *path)
93 for (i = 0; i < path->length / 2; i++)
96 path->peers[i] = path->peers[path->length - i - 1];
97 path->peers[path->length - i - 1] = aux;
103 * Duplicate a path, incrementing short peer's rc.
105 * @param path The path to duplicate.
107 struct CadetPeerPath *
108 path_duplicate (const struct CadetPeerPath *path)
110 struct CadetPeerPath *aux;
113 aux = path_new (path->length);
114 memcpy (aux->peers, path->peers, path->length * sizeof (GNUNET_PEER_Id));
115 for (i = 0; i < aux->length; i++)
116 GNUNET_PEER_change_rc (aux->peers[i], 1);
122 * Get the length of a path.
124 * @param path The path to measure, with the local peer at any point of it.
126 * @return Number of hops to reach destination.
127 * UINT_MAX in case the peer is not in the path.
130 path_get_length (struct CadetPeerPath *path)
140 * Mark path as invalid: keep it aroud for a while to avoid trying it in a loop.
142 * Never invalidates a two-hop (direct) path, only a core handler can do that.
144 * Rationale: DHT_get sometimes returns bad cached results, for instance,
145 * on a locally cached result where the PUT followed a path that is no longer
146 * current. The path must remain "known and marked as invalid" for a while.
148 * @param p Path to invalidate.
151 path_invalidate (struct CadetPeerPath *p)
153 if (NULL != p->path_delete)
156 LOG (GNUNET_ERROR_TYPE_INFO, "Invalidating path %p (%u)\n", p, p->length);
157 p->path_delete = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
158 &path_destroy_delayed, p);
163 * Builds a path from a PeerIdentity array.
165 * @param peers PeerIdentity array.
166 * @param size Size of the @c peers array.
167 * @param myid ID of local peer, to find @c own_pos.
168 * @param own_pos Output parameter: own position in the path.
170 * @return Fixed and shortened path.
172 struct CadetPeerPath *
173 path_build_from_peer_ids (struct GNUNET_PeerIdentity *peers,
176 unsigned int *own_pos)
178 struct CadetPeerPath *path;
179 GNUNET_PEER_Id shortid;
185 LOG (GNUNET_ERROR_TYPE_DEBUG, " Creating path...\n");
186 path = path_new (size);
189 for (i = 0; i < size; i++)
191 LOG (GNUNET_ERROR_TYPE_DEBUG, " - %u: taking %s\n",
192 i, GNUNET_i2s (&peers[i]));
193 shortid = GNUNET_PEER_intern (&peers[i]);
195 /* Check for loops / duplicates */
196 for (j = 0; j < i - offset; j++)
198 if (path->peers[j] == shortid)
200 LOG (GNUNET_ERROR_TYPE_DEBUG, " already exists at pos %u\n", j);
202 LOG (GNUNET_ERROR_TYPE_DEBUG, " offset now %u\n", offset);
203 GNUNET_PEER_change_rc (shortid, -1);
206 LOG (GNUNET_ERROR_TYPE_DEBUG, " storing at %u\n", i - offset);
207 path->peers[i - offset] = shortid;
208 if (path->peers[i - offset] == myid)
209 *own_pos = i - offset;
211 path->length -= offset;
213 if (path->peers[*own_pos] != myid)
215 /* create path: self not found in path through self */
226 * Test if two paths are equivalent (equal or revese of each other).
228 * @param p1 First path
229 * @param p2 Second path
231 * @return GNUNET_YES if both paths are equivalent
232 * GNUNET_NO otherwise
235 path_equivalent (const struct CadetPeerPath *p1,
236 const struct CadetPeerPath *p2)
242 if (p1->length != p2->length)
246 if (0 == memcmp (p1->peers, p2->peers, sizeof (p1->peers[0]) * l))
251 for (i = 0; i <= half; i++)
252 if (p1->peers[i] != p2->peers[l - i])
260 * Test if a path is valid (or at least not known to be invalid).
262 * @param path Path to test.
264 * @return #GNUNET_YES If the path is valid or unknown,
265 * #GNUNET_NO If the path is known to be invalid.
268 path_is_valid (const struct CadetPeerPath *path)
270 return (NULL == path->path_delete);
275 * Destroy the path and free any allocated resources linked to it
277 * @param p the path to destroy
279 * @return GNUNET_OK on success
282 path_destroy (struct CadetPeerPath *p)
287 LOG (GNUNET_ERROR_TYPE_INFO, "destroying path %p (%u)\n", p, p->length);
288 GNUNET_PEER_decrement_rcs (p->peers, p->length);
289 GNUNET_free_non_null (p->peers);
290 if (NULL != p->path_delete)
291 GNUNET_SCHEDULER_cancel (p->path_delete);
300 * @param p1 First path.
301 * @param p2 Second path.
303 * @return > 0 if p1 is longer, or the first differing PEER_Id is higher on p1.
304 * < 0 if p2 is longer, or the first differing PEER_Id is higher on p2.
305 * 0 if they are identical.
308 path_cmp (const struct CadetPeerPath *p1, const struct CadetPeerPath *p2)
310 if (p1->length > p2->length)
313 if (p1->length < p2->length)
316 return memcmp (p1->peers, p2->peers, sizeof (GNUNET_PEER_Id) * p1->length);
321 path_2s (struct CadetPeerPath *p)
327 old = GNUNET_strdup ("");
328 for (i = 0; i < p->length; i++)
330 GNUNET_asprintf (&s, "%s %s",
331 old, GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
332 GNUNET_free_non_null (old);
340 path_debug (struct CadetPeerPath *p)
344 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "PATH:\n");
345 for (i = 0; i < p->length; i++)
346 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " %s\n",
347 GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
348 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "END\n");