/*
* Dijjer - A Peer to Peer HTTP Cache
* Copyright (C) 2004,2005 Change.Tv, Inc
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package dijjer.io.xfer;
import java.util.HashMap;
import java.util.LinkedList;
import dijjer.io.comm.DMT;
import dijjer.io.comm.Message;
import dijjer.io.comm.MessageFilter;
import dijjer.io.comm.Peer;
import dijjer.io.comm.RetrievalException;
import dijjer.io.comm.RoutingTable;
import dijjer.io.comm.UdpSocketManager;
import dijjer.util.BitArray;
import dijjer.util.Buffer;
import dijjer.util.logging.Logger;
/**
* @author ian
*
* To change the template for this generated type comment go to Window - Preferences - Java - Code Generation - Code and
* Comments
*/
public class BlockReceiver {
public static final int RECEIPT_TIMEOUT = 5000;
public static final int INITIAL_RECEIPT_TIMEOUT = 15000;
// TODO: This should be proportional to the calculated round-trip-time, not a constant
public static final int MAX_ROUND_TRIP_TIME = RECEIPT_TIMEOUT;
public static final int MAX_CONSECUTIVE_MISSING_PACKET_REPORTS = 2;
public static final int MAX_SEND_INTERVAL = 500;
PartiallyReceivedBlock _prb;
Peer _sender;
int _uid;
UdpSocketManager _usm;
/** packet : Integer -> reportTime : Long * */
HashMap _recentlyReportedMissingPackets = new HashMap();
public BlockReceiver(UdpSocketManager usm, Peer sender, int uid, PartiallyReceivedBlock prb) {
_sender = sender;
_prb = prb;
_uid = uid;
_usm = usm;
}
public byte[] receive() throws RetrievalException {
int consecutiveMissingPacketReports = 0;
MessageFilter f = MessageFilter.create(INITIAL_RECEIPT_TIMEOUT, DMT.packetTransmit)
.setField(DMT.UID, _uid)
.addType(DMT.allSent)
.addType(DMT.sendAborted);
while (!_prb.allReceived()) {
Message m1 = _usm.waitFor(f);
// Get ready for the next packet
f = MessageFilter.create(RECEIPT_TIMEOUT, DMT.packetTransmit)
.setField(DMT.UID, _uid)
.addType(DMT.allSent)
.addType(DMT.sendAborted);
// The faster we finish the rest of this loop the better!
if ((m1 != null) && (m1.getSpec().equals(DMT.packetTransmit))) {
consecutiveMissingPacketReports = 0;
// packetTransmit received
int packetNo = m1.getInt(DMT.PACKET_NO);
BitArray sent = (BitArray) m1.getObject(DMT.SENT);
Buffer data = (Buffer) m1.getObject(DMT.DATA);
_prb.addPacket(packetNo, data);
// Remove it from rrmp if its in there
_recentlyReportedMissingPackets.remove(new Integer(packetNo));
// Skip checks except for 1 out of 16 packets until we get to the end
if ((_prb.numReceived() < (_prb.getNumPackets() - 16))
&& (packetNo % 16 != 0))
continue;
// Check that we have what the sender thinks we have
LinkedList missing = new LinkedList();
for (int x = 0; x < sent.getSize(); x++) {
if (sent.bitAt(x) && !_prb.isReceived(x)) {
// Sender thinks we have a block which we don't, but have we already
// re-requested it recently?
Long resendTime = (Long) _recentlyReportedMissingPackets.get(new Integer(x));
if ((resendTime == null) || (System.currentTimeMillis() > resendTime.longValue())) {
// Make a note of the earliest time we should resend this,
// based on the number of other packets we are already waiting for
long resendWait = System.currentTimeMillis()
+ (10*MAX_ROUND_TRIP_TIME + (_recentlyReportedMissingPackets.size() * MAX_SEND_INTERVAL));
_recentlyReportedMissingPackets.put(new Integer(x), (new Long(resendWait)));
missing.add(new Integer(x));
}
}
}
if (missing.size() > 0) {
Message mn = DMT.createMissingPacketNotification(_uid, missing);
_usm.send(_sender, mn);
consecutiveMissingPacketReports++;
if (missing.size() > 50) {
Logger.warning("Excessive packet loss : " + mn);
}
}
continue;
}
if ((m1 != null) && m1.getSpec().equals(DMT.sendAborted)) {
_prb.abort(m1.getInt(DMT.REASON), m1.getString(DMT.DESCRIPTION));
throw new RetrievalException(m1.getInt(DMT.REASON), m1.getString(DMT.DESCRIPTION));
}
if ((m1 == null) || (m1.getSpec().equals(DMT.allSent))) {
if (consecutiveMissingPacketReports >= MAX_CONSECUTIVE_MISSING_PACKET_REPORTS) {
_prb.abort(RetrievalException.SENDER_DIED, "Sender unresponsive to resend requests");
LinkedList rem = new LinkedList();
rem.add(_sender);
// TODO: This is a stupid work around for BlockTransferTest and needs to be fixed
if (RoutingTable.getRoutingTable() != null)
RoutingTable.getRoutingTable().removePeers(rem, "Failed to send data after acking request");
throw new RetrievalException(RetrievalException.SENDER_DIED,
"Sender unresponsive to resend requests");
}
LinkedList missing = new LinkedList();
for (int x = 0; x < _prb.getNumPackets(); x++) {
if (!_prb.isReceived(x)) {
missing.addFirst(new Integer(x));
}
}
Message mn = DMT.createMissingPacketNotification(_uid, missing);
_usm.send(_sender, mn);
consecutiveMissingPacketReports++;
if (missing.size() > 50) {
Logger.warning("Sending large missingPacketNotification to " + _sender
+ " due to packet receiver timeout after " + RECEIPT_TIMEOUT + "ms having received "
+ _prb.numReceived());
}
}
}
_usm.send(_sender, DMT.createAllReceived(_uid));
return _prb.getBlock();
}
}