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/*
This file is part of GNUnet.
Copyright (C) 2001-2017 GNUnet e.V.
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., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
/**
* @file cadet/gnunet-service-cadet-new_paths.c
* @brief Information we track per path.
* @author Bartlomiej Polot
* @author Christian Grothoff
*/
#include "platform.h"
#include "gnunet-service-cadet-new_peer.h"
#include "gnunet-service-cadet-new_paths.h"
/**
* Information regarding a possible path to reach a peer.
*/
struct CadetPeerPath
{
/**
* Array of all the peers on the path. If @e hn is non-NULL, the
* last one is our owner.
*/
struct CadetPeerPathEntry *entries;
/**
* Node of this path in the owner's heap. Used to update our position
* in the heap whenever our @e desirability changes.
*/
struct GNUNET_CONTAINER_HeapNode *hn;
/**
* Connections using this path, by destination peer
* (each hop of the path could correspond to an
* active connection).
*/
struct GNUNET_CONTAINER_MultiPeerMap *connections;
/**
* Desirability of the path. How unique is it for the various peers
* on it?
*/
GNUNET_CONTAINER_HeapCostType desirability;
/**
* Length of the @e entries array.
*/
unsigned int entries_length;
};
/**
* Return how much we like keeping the path. This is an aggregate
* score based on various factors, including the age of the path
* (older == better), and the value of this path to all of its ajacent
* peers. For example, long paths that end at a peer that we have no
* shorter way to reach are very desirable, while long paths that end
* at a peer for which we have a shorter way as well are much less
* desirable. Higher values indicate more valuable paths. The
* returned value should be used to decide which paths to remember.
*
* @param path path to return the length for
* @return desirability of the path, larger is more desirable
*/
GNUNET_CONTAINER_HeapCostType
GCPP_get_desirability (const struct CadetPeerPath *path)
{
GNUNET_assert (0);
return 0;
}
/**
* The given peer @a cp used to own this @a path. However, it is no
* longer interested in maintaining it, so the path should be
* discarded or shortened (in case a previous peer on the path finds
* the path desirable).
*
* @param path the path that is being released
* @param cp original final destination of @a path
* @param node entry in the heap of @a cp where this path is anchored
* should be used for updates to the desirability of this path
*/
void
GCPP_acquire (struct CadetPeerPath *path,
struct CadetPeer *cp,
struct GNUNET_CONTAINER_HeapNode *node)
{
GNUNET_assert (0);
}
/**
* The owning peer of this path is no longer interested in maintaining
* it, so the path should be discarded or shortened (in case a
* previous peer on the path finds the path desirable).
*
* @param path the path that is being released
*/
void
GCPP_release (struct CadetPeerPath *path)
{
GNUNET_assert (0);
}
/**
* Updates the score for an entry on the path based
* on our experiences with using @a path.
*
* @param path the path to update
* @param off offset of the entry to update
* @param delta change in the score to apply
*/
void
GCPP_update_score (struct CadetPeerPath *path,
unsigned int off,
int delta)
{
struct CadetPeerPathEntry *entry;
GNUNET_assert (off < path->entries_length);
entry = &path->entries[off];
/* Add delta, with checks for overflows */
if (delta >= 0)
{
if (delta + entry->score < entry->score)
entry->score = INT_MAX;
else
entry->score += delta;
}
else
{
if (delta + entry->score > entry->score)
entry->score = INT_MIN;
else
entry->score += delta;
}
/* FIXME: update path desirability! */
}
/**
* Create a peer path based on the result of a DHT lookup.
*
* @param get_path path of the get request
* @param get_path_length lenght of @a get_path
* @param put_path path of the put request
* @param put_path_length length of the @a put_path
* @return a path through the network
*/
struct CadetPeerPath *
GCPP_path_from_dht (const struct GNUNET_PeerIdentity *get_path,
unsigned int get_path_length,
const struct GNUNET_PeerIdentity *put_path,
unsigned int put_path_length)
{
struct CadetPeerPath *path;
path = GNUNET_new (struct CadetPeerPath);
path->entries_length = get_path_length + put_path_length;
path->entries = GNUNET_new_array (path->entries_length,
struct CadetPeerPathEntry);
for (unsigned int i=0;i<get_path_length + put_path_length;i++)
{
struct CadetPeerPathEntry *entry = &path->entries[i];
const struct GNUNET_PeerIdentity *pid;
pid = (i < get_path_length) ? &get_path[get_path_length - i] : &put_path[path->entries_length - i];
entry->peer = GCP_get (pid,
GNUNET_YES);
entry->path = path;
GCP_path_entry_add (entry->peer,
entry,
i);
}
GNUNET_break (0);
return NULL;
}
/**
* Destroy a path, we no longer need it.
*
* @param p path to destroy.
*/
void
GCPP_path_destroy (struct CadetPeerPath *p)
{
GNUNET_assert (0);
}
/**
* Return the length of the path. Excludes one end of the
* path, so the loopback path has length 0.
*
* @param path path to return the length for
* @return number of peers on the path
*/
unsigned int
GCPP_get_length (struct CadetPeerPath *path)
{
GNUNET_assert (0);
return -1;
}
/**
* Obtain the identity of the peer at offset @a off in @a path.
*
* @param path peer path to inspect
* @param off offset to return, must be smaller than path length
* @param[out] pid where to write the pid, must not be NULL
*/
void
GCPP_get_pid_at_offset (struct CadetPeerPath *path,
unsigned int off,
struct GNUNET_PeerIdentity *pid)
{
GNUNET_assert (0);
}
/* end of gnunet-service-cadet-new_paths.c */
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