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/***************************************************************************
* Copyright (C) 2005 by Joris Guisson *
* joris.guisson@gmail.com *
* *
* This program 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 2 of the License, or *
* (at your option) any later version. *
* *
* This program 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 this program; if not, write to the *
* Free Software Foundation, Inc., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#include <interfaces/functions.h>
#include "oldchokealgorithm.h"
#include "peer.h"
#include "packetwriter.h"
#include "peermanager.h"
using namespace kt;
namespace bt
{
int UploadRateCmp(Peer* pa,Peer* pb)
{
return CompareVal(pa->getUploadRate(),pb->getUploadRate());
}
int DownloadRateCmp(Peer* pa,Peer* pb)
{
return CompareVal(pa->getDownloadRate(),pb->getDownloadRate());
}
OldChokeAlgorithm::OldChokeAlgorithm(): ChokeAlgorithm()
{
opt_unchoke_index = 0;
opt_unchoke = 1;
}
OldChokeAlgorithm::~OldChokeAlgorithm()
{}
void OldChokeAlgorithm::doChoking(PeerManager& pman, bool have_all)
{
if (pman.getNumConnectedPeers() == 0)
return;
downloaders.clear();
interested.clear();
not_interested.clear();
// first alert everybody that we're interested or not
sendInterested(pman,have_all);
// get who is interested and not
updateInterested(pman);
// them sort them;
if (have_all)
{
interested.setCompareFunc(DownloadRateCmp);
interested.sort();
not_interested.setCompareFunc(DownloadRateCmp);
not_interested.sort();
}
else
{
interested.setCompareFunc(UploadRateCmp);
interested.sort();
not_interested.setCompareFunc(UploadRateCmp);
not_interested.sort();
}
// determine the downloaders
updateDownloaders();
// unchoke the not_interested peers
// which have a faster upload rate then the downloaders
sendUnchokes(have_all);
// optimisticly unchoke somebody
optimisticUnchoke(pman);
}
void OldChokeAlgorithm::updateInterested(PeerManager& pman)
{
for (Uint32 i = 0;i < pman.getNumConnectedPeers();i++)
{
Peer* p = pman.getPeer(i);
if (p->getID() == opt_unchoked_peer_id)
continue;
if (p->isInterested())
{
interested.append(p);
}
else
{
not_interested.append(p);
}
}
}
void OldChokeAlgorithm::updateDownloaders()
{
QPtrList<Peer>::iterator itr = interested.begin();
int num = 0;
// send all downloaders an unchoke
for (;itr != interested.end();itr++)
{
Peer* p = *itr;
if (p->getID() == opt_unchoked_peer_id)
continue;
if (num < 4)
{
p->choke();
downloaders.append(p);
num++;
}
else
{
p->choke();
}
}
}
void OldChokeAlgorithm::sendInterested(PeerManager& pman,bool have_all)
{
for (Uint32 i = 0;i < pman.getNumConnectedPeers();i++)
{
Peer* p = pman.getPeer(i);
PacketWriter & pout = p->getPacketWriter();
// if we don't have the entire file, send an intereseted message,
// else we're not intereseted
if (have_all && p->areWeInterested())
pout.sendNotInterested();
else if (!have_all && !p->areWeInterested())
pout.sendInterested();
}
}
void OldChokeAlgorithm::sendUnchokes(bool have_all)
{
if (downloaders.count() == 0)
return;
QPtrList<Peer>::iterator itr = not_interested.begin();
// fd = fastest_downloader
Peer* fd = downloaders.first();
// send all downloaders an unchoke
for (;itr != not_interested.end();itr++)
{
Peer* p = *itr;
if (p->getID() == opt_unchoked_peer_id)
continue;
if ((have_all && p->getDownloadRate() > fd->getDownloadRate()) ||
(!have_all && p->getUploadRate() > fd->getUploadRate()))
{
p->getPacketWriter().sendUnchoke();
}
else
{
p->getPacketWriter().sendChoke();
}
}
}
void OldChokeAlgorithm::optimisticUnchoke(PeerManager& pman)
{
if (pman.getNumConnectedPeers() == 0)
return;
// only switch optimistic unchoked peer every 30 seconds
// (update interval of choker is 10 seconds)
if (opt_unchoke != 3)
{
opt_unchoke++;
return;
}
// Get current time
QTime now = QTime::currentTime();
QPtrList<Peer> peers; // list to store peers to select from
// recently connected peers == peers connected in the last 5 minutes
const int RECENTLY_CONNECT_THRESH = 5*60;
for (Uint32 i = 0;i < pman.getNumConnectedPeers();i++)
{
Peer* p = pman.getPeer(i);
if (p->getConnectTime().secsTo(now) < RECENTLY_CONNECT_THRESH)
{
// we favor recently connected peers 3 times over other peers
// so we add them 3 times to the list
peers.append(p);
peers.append(p);
peers.append(p);
}
else
{
// not recent, so just add one time
peers.append(p);
}
}
// draw a random one from the list and send it an unchoke
opt_unchoke_index = rand() % peers.count();
Peer* lucky_one = peers.at(opt_unchoke_index);
lucky_one->getPacketWriter().sendUnchoke();
opt_unchoked_peer_id = lucky_one->getID();
opt_unchoke = 1;
}
}
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