/* Message - A protocol message which can be send through a DataOutputStream.
Copyright (C) 2003 Mark J. Wielaard
This file is part of Snark.
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, 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 org.klomp.snark;
import java.io.DataOutputStream;
import java.io.IOException;
import net.i2p.data.ByteArray;
import net.i2p.util.ByteCache;
/**
* Used to queue outgoing connections
* sendMessage() should be used to translate them to wire format.
*/
class Message
{
final static byte KEEP_ALIVE = -1;
final static byte CHOKE = 0;
final static byte UNCHOKE = 1;
final static byte INTERESTED = 2;
final static byte UNINTERESTED = 3;
final static byte HAVE = 4;
final static byte BITFIELD = 5;
final static byte REQUEST = 6;
final static byte PIECE = 7;
final static byte CANCEL = 8;
final static byte PORT = 9; // DHT (BEP 5)
final static byte SUGGEST = 13; // Fast (BEP 6)
final static byte HAVE_ALL = 14; // Fast (BEP 6)
final static byte HAVE_NONE = 15; // Fast (BEP 6)
final static byte REJECT = 16; // Fast (BEP 6)
final static byte ALLOWED_FAST = 17; // Fast (BEP 6)
final static byte EXTENSION = 20; // BEP 10
// Not all fields are used for every message.
// KEEP_ALIVE doesn't have a real wire representation
byte type;
// Used for HAVE, REQUEST, PIECE and CANCEL messages.
// Also SUGGEST, REJECT, ALLOWED_FAST
// low byte used for EXTENSION message
// low two bytes used for PORT message
int piece;
// Used for REQUEST, PIECE and CANCEL messages.
// Also REJECT
int begin;
int length;
// Used for PIECE and BITFIELD and EXTENSION messages
byte[] data;
int off;
int len;
// Used to do deferred fetch of data
DataLoader dataLoader;
// now unused
//SimpleTimer.TimedEvent expireEvent;
private static final int BUFSIZE = PeerState.PARTSIZE;
private static final ByteCache _cache = ByteCache.getInstance(16, BUFSIZE);
/** Utility method for sending a message through a DataStream. */
void sendMessage(DataOutputStream dos) throws IOException
{
// KEEP_ALIVE is special.
if (type == KEEP_ALIVE)
{
dos.writeInt(0);
return;
}
ByteArray ba;
// Get deferred data
if (data == null && dataLoader != null) {
ba = dataLoader.loadData(piece, begin, length);
if (ba == null)
return; // hmm will get retried, but shouldn't happen
data = ba.getData();
} else {
ba = null;
}
// Calculate the total length in bytes
// Type is one byte.
int datalen = 1;
// piece is 4 bytes.
if (type == HAVE || type == REQUEST || type == PIECE || type == CANCEL ||
type == SUGGEST || type == REJECT || type == ALLOWED_FAST)
datalen += 4;
// begin/offset is 4 bytes
if (type == REQUEST || type == PIECE || type == CANCEL ||
type == REJECT)
datalen += 4;
// length is 4 bytes
if (type == REQUEST || type == CANCEL ||
type == REJECT)
datalen += 4;
// msg type is 1 byte
if (type == EXTENSION)
datalen += 1;
if (type == PORT)
datalen += 2;
// add length of data for piece or bitfield array.
if (type == BITFIELD || type == PIECE || type == EXTENSION)
datalen += len;
// Send length
dos.writeInt(datalen);
dos.writeByte(type & 0xFF);
// Send additional info (piece number)
if (type == HAVE || type == REQUEST || type == PIECE || type == CANCEL ||
type == SUGGEST || type == REJECT || type == ALLOWED_FAST)
dos.writeInt(piece);
// Send additional info (begin/offset)
if (type == REQUEST || type == PIECE || type == CANCEL ||
type == REJECT)
dos.writeInt(begin);
// Send additional info (length); for PIECE this is implicit.
if (type == REQUEST || type == CANCEL ||
type == REJECT)
dos.writeInt(length);
if (type == EXTENSION)
dos.writeByte((byte) piece & 0xff);
if (type == PORT)
dos.writeShort(piece & 0xffff);
// Send actual data
if (type == BITFIELD || type == PIECE || type == EXTENSION)
dos.write(data, off, len);
// Was pulled from cache in Storage.getPiece() via dataLoader
if (ba != null && ba.getData().length == BUFSIZE)
_cache.release(ba, false);
}
@Override
public String toString()
{
switch (type)
{
case KEEP_ALIVE:
return "KEEP_ALIVE";
case CHOKE:
return "CHOKE";
case UNCHOKE:
return "UNCHOKE";
case INTERESTED:
return "INTERESTED";
case UNINTERESTED:
return "UNINTERESTED";
case HAVE:
return "HAVE(" + piece + ')';
case BITFIELD:
return "BITFIELD";
case REQUEST:
return "REQUEST(" + piece + ',' + begin + ',' + length + ')';
case PIECE:
return "PIECE(" + piece + ',' + begin + ',' + length + ')';
case CANCEL:
return "CANCEL(" + piece + ',' + begin + ',' + length + ')';
case PORT:
return "PORT(" + piece + ')';
case EXTENSION:
return "EXTENSION(" + piece + ',' + data.length + ')';
// fast extensions below here
case SUGGEST:
return "SUGGEST(" + piece + ')';
case HAVE_ALL:
return "HAVE_ALL";
case HAVE_NONE:
return "HAVE_NONE";
case REJECT:
return "REJECT(" + piece + ',' + begin + ',' + length + ')';
case ALLOWED_FAST:
return "ALLOWED_FAST(" + piece + ')';
default:
return "UNKNOWN (" + type + ')';
}
}
}