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/*
This file is part of GNUnet.
(C) 2001 - 2013 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @file mesh/mesh_path.c
* @brief Path handling functions
* @author Bartlomiej Polot
*/
#include "mesh.h"
#include "mesh_path.h"
#include "gnunet-service-mesh_peer.h"
/**
* @brief Destroy a path after some time has past.
*
* If the path is returned from DHT again after a while, try again.
*
* @param cls Closure (path to destroy).
* @param tc Task context.
*/
static void
path_destroy_delayed (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
struct MeshPeerPath *path = cls;
struct MeshPeer *peer;
path->path_delete = GNUNET_SCHEDULER_NO_TASK;
peer = GMP_get_short (path->peers[path->length - 1]);
GMP_remove_path (peer, path);
}
/**
* Create a new path
*
* @param length How many hops will the path have.
*
* @return A newly allocated path with a peer array of the specified length.
*/
struct MeshPeerPath *
path_new (unsigned int length)
{
struct MeshPeerPath *p;
p = GNUNET_malloc (sizeof (struct MeshPeerPath));
if (length > 0)
{
p->length = length;
p->peers = GNUNET_malloc (length * sizeof (GNUNET_PEER_Id));
}
return p;
}
/**
* Invert the path
*
* @param path the path to invert
*/
void
path_invert (struct MeshPeerPath *path)
{
GNUNET_PEER_Id aux;
unsigned int i;
for (i = 0; i < path->length / 2; i++)
{
aux = path->peers[i];
path->peers[i] = path->peers[path->length - i - 1];
path->peers[path->length - i - 1] = aux;
}
}
/**
* Duplicate a path, incrementing short peer's rc.
*
* @param path The path to duplicate.
*/
struct MeshPeerPath *
path_duplicate (const struct MeshPeerPath *path)
{
struct MeshPeerPath *aux;
unsigned int i;
aux = path_new (path->length);
memcpy (aux->peers, path->peers, path->length * sizeof (GNUNET_PEER_Id));
for (i = 0; i < aux->length; i++)
GNUNET_PEER_change_rc (aux->peers[i], 1);
return aux;
}
/**
* Get the length of a path.
*
* @param path The path to measure, with the local peer at any point of it.
*
* @return Number of hops to reach destination.
* UINT_MAX in case the peer is not in the path.
*/
unsigned int
path_get_length (struct MeshPeerPath *path)
{
if (NULL == path)
return UINT_MAX;
return path->length;
}
/**
* Mark path as invalid: keep it aroud for a while to avoid trying it in a loop.
*
* DHT_get sometimes returns bad cached results, for instance, on a locally
* cached result where the PUT followed a path that is no longer current.
*
* @param p Path to invalidate.
*/
void
path_invalidate (struct MeshPeerPath *p)
{
if (GNUNET_SCHEDULER_NO_TASK != p->path_delete)
return;
p->path_delete = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
&path_destroy_delayed, p);
}
/**
* Test if a path is valid (or at least not known to be invalid).
*
* @param path Path to test.
*
* @return #GNUNET_YES If the path is valid or unknown,
* #GNUNET_NO If the path is known to be invalid.
*/
int
path_is_valid (const struct MeshPeerPath *path)
{
return (GNUNET_SCHEDULER_NO_TASK == path->path_delete);
}
/**
* Destroy the path and free any allocated resources linked to it
*
* @param p the path to destroy
*
* @return GNUNET_OK on success
*/
int
path_destroy (struct MeshPeerPath *p)
{
if (NULL == p)
return GNUNET_OK;
GNUNET_PEER_decrement_rcs (p->peers, p->length);
GNUNET_free_non_null (p->peers);
if (GNUNET_SCHEDULER_NO_TASK != p->path_delete)
GNUNET_SCHEDULER_cancel (p->path_delete);
GNUNET_free (p);
return GNUNET_OK;
}
void
path_debug (struct MeshPeerPath *p)
{
unsigned int i;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "PATH:\n");
for (i = 0; i < p->length; i++)
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " %s\n",
GNUNET_i2s (GNUNET_PEER_resolve2 (p->peers[i])));
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "END\n");
}
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