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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;
53 /* During shutdown, the peers peermap might not exist anymore. */
54 if ((GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason) == 0)
56 if (2 >= path->length)
58 /* This is not the place to destroy direct paths, only core_disconnect
59 * should do it and never delay it.
63 peer = GCP_get_short (path->peers[path->length - 1], GNUNET_NO);
65 GCP_remove_path (peer, path);
75 * @param length How many hops will the path have.
77 * @return A newly allocated path with a peer array of the specified length.
79 struct CadetPeerPath *
80 path_new (unsigned int length)
82 struct CadetPeerPath *p;
84 p = GNUNET_new (struct CadetPeerPath);
88 p->peers = GNUNET_malloc (length * sizeof (GNUNET_PEER_Id));
90 LOG (GNUNET_ERROR_TYPE_INFO, "New path %p (%u)\n", p, p->length);
98 * @param path the path to invert
101 path_invert (struct CadetPeerPath *path)
106 for (i = 0; i < path->length / 2; i++)
108 aux = path->peers[i];
109 path->peers[i] = path->peers[path->length - i - 1];
110 path->peers[path->length - i - 1] = aux;
116 * Duplicate a path, incrementing short peer's rc.
118 * @param path The path to duplicate.
120 struct CadetPeerPath *
121 path_duplicate (const struct CadetPeerPath *path)
123 struct CadetPeerPath *aux;
126 aux = path_new (path->length);
127 memcpy (aux->peers, path->peers, path->length * sizeof (GNUNET_PEER_Id));
128 for (i = 0; i < aux->length; i++)
129 GNUNET_PEER_change_rc (aux->peers[i], 1);
135 * Get the length of a path.
137 * @param path The path to measure, with the local peer at any point of it.
139 * @return Number of hops to reach destination.
140 * UINT_MAX in case the peer is not in the path.
143 path_get_length (struct CadetPeerPath *path)
153 * Mark path as invalid: keep it aroud for a while to avoid trying it in a loop.
155 * Never invalidates a two-hop (direct) path, only a core handler can do that.
157 * Rationale: DHT_get sometimes returns bad cached results, for instance,
158 * on a locally cached result where the PUT followed a path that is no longer
159 * current. The path must remain "known and marked as invalid" for a while.
161 * @param p Path to invalidate.
164 path_invalidate (struct CadetPeerPath *p)
166 if (NULL != p->path_delete)
169 LOG (GNUNET_ERROR_TYPE_INFO, "Invalidating path %p (%u)\n", p, p->length);
170 p->path_delete = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
171 &path_destroy_delayed, p);
176 * Builds a path from a PeerIdentity array.
178 * @param peers PeerIdentity array.
179 * @param size Size of the @c peers array.
180 * @param myid ID of local peer, to find @c own_pos.
181 * @param own_pos Output parameter: own position in the path.
183 * @return Fixed and shortened path.
185 struct CadetPeerPath *
186 path_build_from_peer_ids (struct GNUNET_PeerIdentity *peers,
189 unsigned int *own_pos)
191 struct CadetPeerPath *path;
192 GNUNET_PEER_Id shortid;
198 LOG (GNUNET_ERROR_TYPE_DEBUG, " Creating path...\n");
199 path = path_new (size);
202 for (i = 0; i < size; i++)
204 LOG (GNUNET_ERROR_TYPE_DEBUG, " - %u: taking %s\n",
205 i, GNUNET_i2s (&peers[i]));
206 shortid = GNUNET_PEER_intern (&peers[i]);
208 /* Check for loops / duplicates */
209 for (j = 0; j < i - offset; j++)
211 if (path->peers[j] == shortid)
213 LOG (GNUNET_ERROR_TYPE_DEBUG, " already exists at pos %u\n", j);
215 LOG (GNUNET_ERROR_TYPE_DEBUG, " offset now %u\n", offset);
216 GNUNET_PEER_change_rc (shortid, -1);
219 LOG (GNUNET_ERROR_TYPE_DEBUG, " storing at %u\n", i - offset);
220 path->peers[i - offset] = shortid;
221 if (path->peers[i - offset] == myid)
222 *own_pos = i - offset;
224 path->length -= offset;
226 if (path->peers[*own_pos] != myid)
228 /* create path: self not found in path through self */
239 * Test if two paths are equivalent (equal or revese of each other).
241 * @param p1 First path
242 * @param p2 Second path
244 * @return GNUNET_YES if both paths are equivalent
245 * GNUNET_NO otherwise
248 path_equivalent (const struct CadetPeerPath *p1,
249 const struct CadetPeerPath *p2)
255 if (NULL == p1 || NULL == p2)
258 if (p1->length != p2->length)
262 if (0 == memcmp (p1->peers, p2->peers, sizeof (p1->peers[0]) * l))
267 for (i = 0; i <= half; i++)
268 if (p1->peers[i] != p2->peers[l - i])
276 * Test if a path is valid (or at least not known to be invalid).
278 * @param path Path to test.
280 * @return #GNUNET_YES If the path is valid or unknown,
281 * #GNUNET_NO If the path is known to be invalid.
284 path_is_valid (const struct CadetPeerPath *path)
286 return (NULL == path->path_delete);
291 * Destroy the path and free any allocated resources linked to it
293 * @param p the path to destroy
295 * @return GNUNET_OK on success
298 path_destroy (struct CadetPeerPath *p)
303 LOG (GNUNET_ERROR_TYPE_INFO, "destroying path %p (%u)\n", p, p->length);
304 GNUNET_PEER_decrement_rcs (p->peers, p->length);
305 GNUNET_free_non_null (p->peers);
306 if (NULL != p->path_delete)
307 GNUNET_SCHEDULER_cancel (p->path_delete);
316 * @param p1 First path.
317 * @param p2 Second path.
319 * @return > 0 if p1 is longer, or the first differing PEER_Id is higher on p1.
320 * < 0 if p2 is longer, or the first differing PEER_Id is higher on p2.
321 * 0 if they are identical.
324 path_cmp (const struct CadetPeerPath *p1, const struct CadetPeerPath *p2)
326 if (p1->length > p2->length)
329 if (p1->length < p2->length)
332 return memcmp (p1->peers, p2->peers, sizeof (GNUNET_PEER_Id) * p1->length);
337 path_2s (struct CadetPeerPath *p)
343 old = GNUNET_strdup ("");
344 for (i = 0; i < p->length; i++)
346 GNUNET_asprintf (&s, "%s %s",
347 old, GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
348 GNUNET_free_non_null (old);
356 path_debug (struct CadetPeerPath *p)
360 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "PATH:\n");
361 for (i = 0; i < p->length; i++)
362 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " %s\n",
363 GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
364 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "END\n");