RetroShare/libretroshare/src/grouter/groutermatrix.cc

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/*
* libretroshare/src/services: groutermatrix.cc
*
* Services for RetroShare.
*
* Copyright 2013 by Cyril Soler
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License Version 2 as published by the Free Software Foundation.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*
* Please report all bugs and problems to "csoler@users.sourceforge.net".
*
*/
#include "groutertypes.h"
#include "groutermatrix.h"
#include "grouteritems.h"
GRouterMatrix::GRouterMatrix()
{
_proba_need_updating = true ;
}
bool GRouterMatrix::addRoutingClue(const GRouterKeyId& key_id,const RsPeerId& source_friend,float weight)
{
// 1 - get the friend index.
//
uint32_t fid = getFriendId(source_friend) ;
// 2 - get the Key map, and add the routing clue.
//
time_t now = time(NULL) ;
RoutingMatrixHitEntry rc ;
rc.weight = weight ;
rc.time_stamp = now ;
rc.friend_id = fid ;
std::list<RoutingMatrixHitEntry>& lst( _routing_clues[key_id] ) ;
// Prevent flooding. Happens in two scenarii:
// 1 - a user restarts RS very often => keys get republished for some reason
// 2 - a user intentionnaly floods a key
//
// Solution is to look for all recorded events, and not add any new event if an event came from the same friend
// too close in the past. Going through the list is not costly since it is bounded to RS_GROUTER_MATRIX_MAX_HIT_ENTRIES elemts.
for(std::list<RoutingMatrixHitEntry>::const_iterator mit(lst.begin());mit!=lst.end();++mit)
if((*mit).friend_id == fid && (*mit).time_stamp + RS_GROUTER_MATRIX_MIN_TIME_BETWEEN_HITS > now)
{
std::cerr << "GRouterMatrix::addRoutingClue(): too many clues for key " << key_id.toStdString() << " from friend " << source_friend << " in a small interval of " << now - lst.front().time_stamp << " seconds. Flooding?" << std::endl;
return false ;
}
lst.push_front(rc) ; // create it if necessary
// Remove older elements
//
uint32_t sz = lst.size() ; // O(n)!
for(uint32_t i=RS_GROUTER_MATRIX_MAX_HIT_ENTRIES;i<sz;++i)
{
lst.pop_back() ;
std::cerr << "Poped one entry" << std::endl;
}
_proba_need_updating = true ; // always, since we added new clues.
return true ;
}
uint32_t GRouterMatrix::getFriendId_const(const RsPeerId& source_friend) const
{
std::map<RsPeerId,uint32_t>::const_iterator it = _friend_indices.find(source_friend) ;
if(it == _friend_indices.end())
return _reverse_friend_indices.size() ;
else
return it->second ;
}
uint32_t GRouterMatrix::getFriendId(const RsPeerId& source_friend)
{
std::map<RsPeerId,uint32_t>::const_iterator it = _friend_indices.find(source_friend) ;
if(it == _friend_indices.end())
{
// add a new friend
uint32_t new_id = _reverse_friend_indices.size() ;
_reverse_friend_indices.push_back(source_friend) ;
_friend_indices[source_friend] = new_id ;
return new_id ;
}
else
return it->second ;
}
void GRouterMatrix::getListOfKnownKeys(std::vector<GRouterKeyId>& key_ids) const
{
key_ids.clear() ;
for(std::map<GRouterKeyId,std::vector<float> >::const_iterator it(_time_combined_hits.begin());it!=_time_combined_hits.end();++it)
key_ids.push_back(it->first) ;
}
void GRouterMatrix::debugDump() const
{
std::cerr << " Proba needs up: " << _proba_need_updating << std::endl;
std::cerr << " Known keys: " << _time_combined_hits.size() << std::endl;
std::cerr << " Routing events: " << std::endl;
time_t now = time(NULL) ;
for(std::map<GRouterKeyId, std::list<RoutingMatrixHitEntry> >::const_iterator it(_routing_clues.begin());it!=_routing_clues.end();++it)
{
std::cerr << " " << it->first.toStdString() << " : " ;
for(std::list<RoutingMatrixHitEntry>::const_iterator it2(it->second.begin());it2!=it->second.end();++it2)
std::cerr << now - (*it2).time_stamp << " (" << (*it2).friend_id << "," << (*it2).weight << ") " ;
std::cerr << std::endl;
}
std::cerr << " Routing values: " << std::endl;
for(std::map<GRouterKeyId, std::vector<float> >::const_iterator it(_time_combined_hits.begin());it!=_time_combined_hits.end();++it)
{
std::cerr << " " << it->first.toStdString() << " : " ;
for(uint32_t i=0;i<it->second.size();++i)
std::cerr << it->second[i] << " " ;
std::cerr << std::endl;
}
}
bool GRouterMatrix::computeRoutingProbabilities(const GRouterKeyId& key_id, const std::vector<RsPeerId>& friends, std::vector<float>& probas) const
{
// Routing probabilities are computed according to routing clues
//
// For a given key, each friend has a known set of routing clues (time_t, weight)
// We combine these to compute a static weight for each friend/key pair.
// This is performed in updateRoutingProbabilities()
//
// Then for a given list of online friends, the weights are computed into probabilities,
// that always sum up to 1.
//
if(_proba_need_updating)
std::cerr << "GRouterMatrix::computeRoutingProbabilities(): matrix is not up to date. Not a real problem, but still..." << std::endl;
probas.resize(friends.size(),0.0f) ;
float total = 0.0f ;
std::map<GRouterKeyId,std::vector<float> >::const_iterator it2 = _time_combined_hits.find(key_id) ;
if(it2 == _time_combined_hits.end())
{
// The key is not known. In this case, we return a zero probability for all peers.
//
float p = 0.0f;//1.0f / friends.size() ;
probas.clear() ;
probas.resize(friends.size(),p) ;
std::cerr << "GRouterMatrix::computeRoutingProbabilities(): key id " << key_id.toStdString() << " does not exist! Returning uniform probabilities." << std::endl;
return false ;
}
const std::vector<float>& w(it2->second) ;
for(uint32_t i=0;i<friends.size();++i)
{
uint32_t findex = getFriendId_const(friends[i]) ;
if(findex >= w.size())
probas[i] = 0.0f ;
else
{
probas[i] = w[findex] ;
total += w[findex] ;
}
}
if(total > 0.0f)
for(uint32_t i=0;i<friends.size();++i)
probas[i] /= total ;
return true ;
}
bool GRouterMatrix::updateRoutingProbabilities()
{
if(!_proba_need_updating)
return false ;
time_t now = time(NULL) ;
for(std::map<GRouterKeyId, std::list<RoutingMatrixHitEntry> >::const_iterator it(_routing_clues.begin());it!=_routing_clues.end();++it)
{
std::cerr << " " << it->first.toStdString() << " : " ;
std::vector<float>& v(_time_combined_hits[it->first]) ;
v.clear() ;
v.resize(_friend_indices.size(),0.0f) ;
for(std::list<RoutingMatrixHitEntry>::const_iterator it2(it->second.begin());it2!=it->second.end();++it2)
{
float time_difference_in_days = 1 + (now - (*it2).time_stamp ) / 86400.0f ;
v[(*it2).friend_id] += (*it2).weight / (time_difference_in_days*time_difference_in_days) ;
}
}
std::cerr << " done." << std::endl;
_proba_need_updating = false ;
return true ;
}
bool GRouterMatrix::saveList(std::list<RsItem*>& items)
{
std::cerr << " GRoutingMatrix::saveList()" << std::endl;
RsGRouterMatrixFriendListItem *item = new RsGRouterMatrixFriendListItem ;
item->reverse_friend_indices = _reverse_friend_indices ;
items.push_back(item) ;
for(std::map<GRouterKeyId,std::list<RoutingMatrixHitEntry> >::const_iterator it(_routing_clues.begin());it!=_routing_clues.end();++it)
{
RsGRouterMatrixCluesItem *item = new RsGRouterMatrixCluesItem ;
item->destination_key = it->first ;
item->clues = it->second ;
items.push_back(item) ;
}
return true ;
}
bool GRouterMatrix::loadList(std::list<RsItem*>& items)
{
RsGRouterMatrixFriendListItem *itm1 = NULL ;
RsGRouterMatrixCluesItem *itm2 = NULL ;
std::cerr << " GRoutingMatrix::loadList()" << std::endl;
for(std::list<RsItem*>::const_iterator it(items.begin());it!=items.end();++it)
{
if(NULL != (itm2 = dynamic_cast<RsGRouterMatrixCluesItem*>(*it)))
{
std::cerr << " initing routing clues." << std::endl;
_routing_clues[itm2->destination_key] = itm2->clues ;
_proba_need_updating = true ; // notifies to re-compute all the info.
}
if(NULL != (itm1 = dynamic_cast<RsGRouterMatrixFriendListItem*>(*it)))
{
_reverse_friend_indices = itm1->reverse_friend_indices ;
_friend_indices.clear() ;
for(uint32_t i=0;i<_reverse_friend_indices.size();++i)
_friend_indices[_reverse_friend_indices[i]] = i ;
_proba_need_updating = true ; // notifies to re-compute all the info.
}
}
return true ;
}