/*
* Mojito Distributed Hash Table (Mojito DHT)
* Copyright (C) 2006-2007 LimeWire LLC
*
* 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.limewire.mojito.messages.impl;
import java.io.IOException;
import java.io.OutputStream;
import java.net.SocketAddress;
import java.net.UnknownHostException;
import java.security.Signature;
import java.security.SignatureException;
import org.limewire.io.ByteBufferOutputStream;
import org.limewire.io.NetworkUtils;
import org.limewire.mojito.Context;
import org.limewire.mojito.KUID;
import org.limewire.mojito.io.MessageInputStream;
import org.limewire.mojito.io.MessageOutputStream;
import org.limewire.mojito.messages.DHTMessage;
import org.limewire.mojito.messages.MessageID;
import org.limewire.mojito.routing.Contact;
import org.limewire.mojito.routing.Vendor;
import org.limewire.mojito.routing.Version;
/**
* An abstract implementation of DHTMessage
*/
abstract class AbstractDHTMessage implements DHTMessage {
protected final Context context;
private final OpCode opcode;
private final Contact contact;
private final MessageID messageId;
private final Version msgVersion;
private byte[] payload;
public AbstractDHTMessage(Context context,
OpCode opcode, Contact contact, MessageID messageId, Version msgVersion) {
if (opcode == null) {
throw new NullPointerException("OpCode is null");
}
if (contact == null) {
throw new NullPointerException("Contact is null");
}
if (messageId == null) {
throw new NullPointerException("MessageID is null");
}
if (msgVersion == null) {
throw new NullPointerException("Version is null");
}
this.context = context;
this.opcode = opcode;
this.contact = contact;
this.messageId = messageId;
this.msgVersion = msgVersion;
}
public AbstractDHTMessage(Context context, OpCode opcode, SocketAddress src,
MessageID messageId, Version msgVersion, MessageInputStream in) throws IOException {
if (opcode == null) {
throw new NullPointerException("OpCode is null");
}
if (messageId == null) {
throw new NullPointerException("MessageID is null");
}
if (msgVersion == null) {
throw new NullPointerException("Version is null");
}
this.context = context;
this.opcode = opcode;
this.messageId = messageId;
this.msgVersion = msgVersion;
Vendor vendor = in.readVendor();
Version version = in.readVersion();
KUID nodeId = in.readKUID();
SocketAddress contactAddress = in.readSocketAddress();
if (contactAddress == null) {
throw new UnknownHostException("Contact Address is null");
}
int instanceId = in.readUnsignedByte();
int flags = in.readUnsignedByte();
this.contact = createContact(src, vendor, version,
nodeId, contactAddress, instanceId, flags);
int extensionsLength = in.readUnsignedShort();
in.skip(extensionsLength);
}
protected abstract Contact createContact(SocketAddress src, Vendor vendor, Version version,
KUID nodeId, SocketAddress contactAddress, int instanceId, int flags);
public Context getContext() {
return context;
}
public OpCode getOpCode() {
return opcode;
}
public Contact getContact() {
return contact;
}
public MessageID getMessageID() {
return messageId;
}
public Version getMessageVersion() {
return msgVersion;
}
public void write(OutputStream os) throws IOException {
serialize();
MessageOutputStream out = new MessageOutputStream(os);
// --- GNUTELLA HEADER ---
messageId.write(out); // 0-15
out.writeByte(DHTMessage.F_DHT_MESSAGE); // 16
out.writeVersion(getMessageVersion()); //17-18
// Length is in Little-Endian!
out.write((payload.length ) & 0xFF); // 19-22
out.write((payload.length >> 8) & 0xFF);
out.write((payload.length >> 16) & 0xFF);
out.write((payload.length >> 24) & 0xFF);
// --- GNUTELLA PAYLOAD ---
out.write(payload, 0, payload.length); // 23-n
}
private synchronized void serialize() throws IOException {
if (payload != null) {
return;
}
ByteBufferOutputStream baos = new ByteBufferOutputStream(640);
MessageOutputStream out = new MessageOutputStream(baos);
// --- MOJITO HEADER CONINUED ---
writeHeader(out);
// --- MOJITO BODY ---
writeBody(out);
out.close();
payload = baos.toByteArray();
}
protected void writeHeader(MessageOutputStream out) throws IOException {
out.writeOpCode(getOpCode()); // 0
out.writeVendor(getContact().getVendor()); // 1-3
out.writeVersion(getContact().getVersion()); // 4-5
out.writeKUID(getContact().getNodeID()); // 6-25
out.writeSocketAddress(getContact().getContactAddress()); // 26-33
out.writeByte(getContact().getInstanceID()); // 34
out.writeByte(getContact().getFlags()); // 35
// Write the extended header
writeExtendedHeader(out); // 36-
}
private void writeExtendedHeader(MessageOutputStream out) throws IOException {
out.writeShort(0); // 36-37
}
protected abstract void writeBody(MessageOutputStream out) throws IOException;
protected void initSignature(Signature signature)
throws SignatureException {
try {
// Destination
SocketAddress myExternalAddress = context.getContactAddress();
signature.update(NetworkUtils.getBytes(myExternalAddress, java.nio.ByteOrder.BIG_ENDIAN));
// Source
SocketAddress contactAddress = getContact().getContactAddress();
signature.update(NetworkUtils.getBytes(contactAddress, java.nio.ByteOrder.BIG_ENDIAN));
} catch (UnknownHostException err) {
throw new SignatureException(err);
}
}
public final int getLength() {
try {
serialize();
return payload.length;
} catch (IOException impossible) {
return -1;
}
}
}