2 This file is part of GNUnet.
3 Copyright (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
8 option) any later version.
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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
16 along with GNUnet; see the file COPYING. If not, write to the
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 if ((GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason) != 0)
53 path->path_delete = NULL;
54 peer = GCP_get_short (path->peers[path->length - 1]);
56 GCP_remove_path (peer, path);
65 * @param length How many hops will the path have.
67 * @return A newly allocated path with a peer array of the specified length.
69 struct CadetPeerPath *
70 path_new (unsigned int length)
72 struct CadetPeerPath *p;
74 p = GNUNET_new (struct CadetPeerPath);
78 p->peers = GNUNET_malloc (length * sizeof (GNUNET_PEER_Id));
80 LOG (GNUNET_ERROR_TYPE_INFO, "New path %p (%u)\n", path, path->length);
88 * @param path the path to invert
91 path_invert (struct CadetPeerPath *path)
96 for (i = 0; i < path->length / 2; i++)
99 path->peers[i] = path->peers[path->length - i - 1];
100 path->peers[path->length - i - 1] = aux;
106 * Duplicate a path, incrementing short peer's rc.
108 * @param path The path to duplicate.
110 struct CadetPeerPath *
111 path_duplicate (const struct CadetPeerPath *path)
113 struct CadetPeerPath *aux;
116 aux = path_new (path->length);
117 memcpy (aux->peers, path->peers, path->length * sizeof (GNUNET_PEER_Id));
118 for (i = 0; i < aux->length; i++)
119 GNUNET_PEER_change_rc (aux->peers[i], 1);
125 * Get the length of a path.
127 * @param path The path to measure, with the local peer at any point of it.
129 * @return Number of hops to reach destination.
130 * UINT_MAX in case the peer is not in the path.
133 path_get_length (struct CadetPeerPath *path)
143 * Mark path as invalid: keep it aroud for a while to avoid trying it in a loop.
145 * Never invalidates a two-hop (direct) path, only a core handler can do that.
147 * Rationale: DHT_get sometimes returns bad cached results, for instance,
148 * on a locally cached result where the PUT followed a path that is no longer
149 * current. The path must remain "known and marked as invalid" for a while.
151 * @param p Path to invalidate.
154 path_invalidate (struct CadetPeerPath *p)
156 if (NULL != p->path_delete)
159 LOG (GNUNET_ERROR_TYPE_INFO, "Invalidating path %p (%u)\n", p, p->length);
160 p->path_delete = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
161 &path_destroy_delayed, p);
166 * Builds a path from a PeerIdentity array.
168 * @param peers PeerIdentity array.
169 * @param size Size of the @c peers array.
170 * @param myid ID of local peer, to find @c own_pos.
171 * @param own_pos Output parameter: own position in the path.
173 * @return Fixed and shortened path.
175 struct CadetPeerPath *
176 path_build_from_peer_ids (struct GNUNET_PeerIdentity *peers,
179 unsigned int *own_pos)
181 struct CadetPeerPath *path;
182 GNUNET_PEER_Id shortid;
188 LOG (GNUNET_ERROR_TYPE_DEBUG, " Creating path...\n");
189 path = path_new (size);
192 for (i = 0; i < size; i++)
194 LOG (GNUNET_ERROR_TYPE_DEBUG, " - %u: taking %s\n",
195 i, GNUNET_i2s (&peers[i]));
196 shortid = GNUNET_PEER_intern (&peers[i]);
198 /* Check for loops / duplicates */
199 for (j = 0; j < i - offset; j++)
201 if (path->peers[j] == shortid)
203 LOG (GNUNET_ERROR_TYPE_DEBUG, " already exists at pos %u\n", j);
205 LOG (GNUNET_ERROR_TYPE_DEBUG, " offset now %u\n", offset);
206 GNUNET_PEER_change_rc (shortid, -1);
209 LOG (GNUNET_ERROR_TYPE_DEBUG, " storing at %u\n", i - offset);
210 path->peers[i - offset] = shortid;
211 if (path->peers[i - offset] == myid)
212 *own_pos = i - offset;
214 path->length -= offset;
216 if (path->peers[*own_pos] != myid)
218 /* create path: self not found in path through self */
229 * Test if two paths are equivalent (equal or revese of each other).
231 * @param p1 First path
232 * @param p2 Second path
234 * @return GNUNET_YES if both paths are equivalent
235 * GNUNET_NO otherwise
238 path_equivalent (const struct CadetPeerPath *p1,
239 const struct CadetPeerPath *p2)
245 if (p1->length != p2->length)
249 if (0 == memcmp (p1->peers, p2->peers, sizeof (p1->peers[0]) * l))
254 for (i = 0; i <= half; i++)
255 if (p1->peers[i] != p2->peers[l - i])
263 * Test if a path is valid (or at least not known to be invalid).
265 * @param path Path to test.
267 * @return #GNUNET_YES If the path is valid or unknown,
268 * #GNUNET_NO If the path is known to be invalid.
271 path_is_valid (const struct CadetPeerPath *path)
273 return (NULL == path->path_delete);
278 * Destroy the path and free any allocated resources linked to it
280 * @param p the path to destroy
282 * @return GNUNET_OK on success
285 path_destroy (struct CadetPeerPath *p)
290 LOG (GNUNET_ERROR_TYPE_INFO, "destroying path %p (%u)\n", p, p->length);
291 GNUNET_PEER_decrement_rcs (p->peers, p->length);
292 GNUNET_free_non_null (p->peers);
293 if (NULL != p->path_delete)
294 GNUNET_SCHEDULER_cancel (p->path_delete);
303 * @param p1 First path.
304 * @param p2 Second path.
306 * @return > 0 if p1 is longer, or the first differing PEER_Id is higher on p1.
307 * < 0 if p2 is longer, or the first differing PEER_Id is higher on p2.
308 * 0 if they are identical.
311 path_cmp (const struct CadetPeerPath *p1, const struct CadetPeerPath *p2)
313 if (p1->length > p2->length)
316 if (p1->length < p2->length)
319 return memcmp (p1->peers, p2->peers, sizeof (GNUNET_PEER_Id) * p1->length);
324 path_2s (struct CadetPeerPath *p)
330 old = GNUNET_strdup ("");
331 for (i = 0; i < p->length; i++)
333 GNUNET_asprintf (&s, "%s %s",
334 old, GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
335 GNUNET_free_non_null (old);
343 path_debug (struct CadetPeerPath *p)
347 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "PATH:\n");
348 for (i = 0; i < p->length; i++)
349 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " %s\n",
350 GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
351 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "END\n");