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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.
36 * Removes the path from the peer (must not be used for direct paths).
38 * @param cls Closure (path to destroy).
41 path_destroy_delayed (void *cls)
43 struct CadetPeerPath *path = cls;
44 struct CadetPeer *peer;
46 path->path_delete = NULL;
47 LOG (GNUNET_ERROR_TYPE_INFO,
48 "Destroy delayed %p (%u)\n",
51 GNUNET_assert (2 < path->length);
52 peer = GCP_get_short (path->peers[path->length - 1],
54 GNUNET_assert (NULL != peer);
55 GCP_remove_path (peer, path);
62 * @param length How many hops will the path have.
63 * @return A newly allocated path with a peer array of the specified length.
65 struct CadetPeerPath *
66 path_new (unsigned int length)
68 struct CadetPeerPath *p;
70 p = GNUNET_new (struct CadetPeerPath);
74 p->peers = GNUNET_malloc (length * sizeof (GNUNET_PEER_Id));
76 LOG (GNUNET_ERROR_TYPE_INFO, "New path %p (%u)\n", p, p->length);
84 * @param path the path to invert
87 path_invert (struct CadetPeerPath *path)
92 for (i = 0; i < path->length / 2; i++)
95 path->peers[i] = path->peers[path->length - i - 1];
96 path->peers[path->length - i - 1] = aux;
102 * Duplicate a path, incrementing short peer's rc.
104 * @param path The path to duplicate.
106 struct CadetPeerPath *
107 path_duplicate (const struct CadetPeerPath *path)
109 struct CadetPeerPath *aux;
112 aux = path_new (path->length);
113 GNUNET_memcpy (aux->peers,
115 path->length * sizeof (GNUNET_PEER_Id));
116 for (i = 0; i < aux->length; i++)
117 GNUNET_PEER_change_rc (aux->peers[i], 1);
123 * Get the length of a path.
125 * @param path The path to measure, with the local peer at any point of it.
127 * @return Number of hops to reach destination.
128 * UINT_MAX in case the peer is not in the path.
131 path_get_length (struct CadetPeerPath *path)
141 * Mark path as invalid: keep it aroud for a while to avoid trying it in a loop.
143 * Never invalidates a two-hop (direct) path, only a core handler can do that.
145 * Rationale: DHT_get sometimes returns bad cached results, for instance,
146 * on a locally cached result where the PUT followed a path that is no longer
147 * current. The path must remain "known and marked as invalid" for a while.
149 * @param p Path to invalidate.
152 path_invalidate (struct CadetPeerPath *p)
154 if (NULL != p->path_delete)
157 LOG (GNUNET_ERROR_TYPE_INFO,
158 "Invalidating path %p (%u)\n",
162 = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
163 &path_destroy_delayed, p);
168 * Builds a path from a PeerIdentity array.
170 * @param peers PeerIdentity array.
171 * @param size Size of the @c peers array.
172 * @param myid ID of local peer, to find @c own_pos.
173 * @param own_pos Output parameter: own position in the path.
175 * @return Fixed and shortened path.
177 struct CadetPeerPath *
178 path_build_from_peer_ids (struct GNUNET_PeerIdentity *peers,
181 unsigned int *own_pos)
183 struct CadetPeerPath *path;
184 GNUNET_PEER_Id shortid;
190 LOG (GNUNET_ERROR_TYPE_DEBUG, " Creating path...\n");
191 path = path_new (size);
194 for (i = 0; i < size; i++)
196 LOG (GNUNET_ERROR_TYPE_DEBUG, " - %u: taking %s\n",
197 i, GNUNET_i2s (&peers[i]));
198 shortid = GNUNET_PEER_intern (&peers[i]);
200 /* Check for loops / duplicates */
201 for (j = 0; j < i - offset; j++)
203 if (path->peers[j] == shortid)
205 LOG (GNUNET_ERROR_TYPE_DEBUG, " already exists at pos %u\n", j);
207 LOG (GNUNET_ERROR_TYPE_DEBUG, " offset now %u\n", offset);
208 GNUNET_PEER_change_rc (shortid, -1);
211 LOG (GNUNET_ERROR_TYPE_DEBUG, " storing at %u\n", i - offset);
212 path->peers[i - offset] = shortid;
213 if (path->peers[i - offset] == myid)
214 *own_pos = i - offset;
216 path->length -= offset;
218 if (path->peers[*own_pos] != myid)
220 /* create path: self not found in path through self */
231 * Test if two paths are equivalent (equal or revese of each other).
233 * @param p1 First path
234 * @param p2 Second path
236 * @return #GNUNET_YES if both paths are equivalent
237 * #GNUNET_NO otherwise
240 path_equivalent (const struct CadetPeerPath *p1,
241 const struct CadetPeerPath *p2)
247 if (NULL == p1 || NULL == p2)
250 if (p1->length != p2->length)
254 if (0 == memcmp (p1->peers, p2->peers, sizeof (p1->peers[0]) * l))
259 for (i = 0; i <= half; i++)
260 if (p1->peers[i] != p2->peers[l - i])
268 * Test if a path is valid (or at least not known to be invalid).
270 * @param path Path to test.
272 * @return #GNUNET_YES If the path is valid or unknown,
273 * #GNUNET_NO If the path is known to be invalid.
276 path_is_valid (const struct CadetPeerPath *path)
278 return (NULL == path->path_delete);
283 * Destroy the path and free any allocated resources linked to it
285 * @param p the path to destroy
287 * @return #GNUNET_OK on success
290 path_destroy (struct CadetPeerPath *p)
295 LOG (GNUNET_ERROR_TYPE_INFO,
296 "destroying path %p (%u)\n",
299 GNUNET_PEER_decrement_rcs (p->peers, p->length);
300 GNUNET_free_non_null (p->peers);
301 if (NULL != p->path_delete)
302 GNUNET_SCHEDULER_cancel (p->path_delete);
311 * @param p1 First path.
312 * @param p2 Second path.
314 * @return > 0 if p1 is longer, or the first differing PEER_Id is higher on p1.
315 * < 0 if p2 is longer, or the first differing PEER_Id is higher on p2.
316 * 0 if they are identical.
319 path_cmp (const struct CadetPeerPath *p1,
320 const struct CadetPeerPath *p2)
322 if (p1->length > p2->length)
325 if (p1->length < p2->length)
328 return memcmp (p1->peers,
330 sizeof (GNUNET_PEER_Id) * p1->length);
335 path_2s (struct CadetPeerPath *p)
341 old = GNUNET_strdup ("");
342 for (i = 0; i < p->length; i++)
344 GNUNET_asprintf (&s, "%s %s",
345 old, GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
346 GNUNET_free_non_null (old);
354 path_debug (struct CadetPeerPath *p)
358 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "PATH:\n");
359 for (i = 0; i < p->length; i++)
360 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " %s\n",
361 GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
362 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "END\n");