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package net.i2p.data.i2np;
/*
* free (adj.): unencumbered; not under the control of others
* Written by jrandom in 2003 and released into the public domain
* with no warranty of any kind, either expressed or implied.
* It probably won't make your computer catch on fire, or eat
* your children, but it might. Use at your own risk.
*
*/
import net.i2p.I2PAppContext;
import net.i2p.data.DataHelper;
import net.i2p.data.TunnelId;
import net.i2p.util.Log;
/**
* Defines the message sent between one tunnel's endpoint and another's gateway.
* format: { tunnelId, sizeof(i2npMessage.toByteArray()), i2npMessage.toByteArray() }
*
*/
public class TunnelGatewayMessage extends FastI2NPMessageImpl {
private TunnelId _tunnelId;
private I2NPMessage _msg;
private byte _msgData[];
//private Exception _creator;
public final static int MESSAGE_TYPE = 19;
/** if we can't deliver a tunnel message in 10s, forget it */
private static final int EXPIRATION_PERIOD = 10*1000;
public TunnelGatewayMessage(I2PAppContext context) {
super(context);
setMessageExpiration(context.clock().now() + EXPIRATION_PERIOD);
//_creator = new Exception("i made this");
}
public TunnelId getTunnelId() { return _tunnelId; }
/**
* @throws IllegalStateException if id previously set, to protect saved checksum
*/
public void setTunnelId(TunnelId id) {
if (_tunnelId != null)
throw new IllegalStateException();
_tunnelId = id;
}
/**
* Warning, at the IBGW, where the message was read in,
* this will be an UnknownI2NPMessage.
* If you need a real message class, use UnknownI2NPMessage.convert().
*
* Warning, will be null after message has been written.
*
* Note that if you change the expiration on the embedded message it will
* mess up the checksum of this message, so don't do that.
*/
public I2NPMessage getMessage() { return _msg; }
/**
* @throws IllegalStateException if msg previously set, to protect saved checksum
*/
public void setMessage(I2NPMessage msg) {
if (_msg != null)
throw new IllegalStateException();
if (msg == null)
throw new IllegalArgumentException("dont set me to null!");
_msg = msg;
}
protected int calculateWrittenLength() {
int rv = 4 + 2;
synchronized (this) {
if (_msg != null)
rv += _msg.getMessageSize();
else if (_msgData != null)
rv += _msgData.length;
else
throw new IllegalStateException();
}
return rv;
}
/** write the message body to the output array, starting at the given index */
protected int writeMessageBody(byte out[], int curIndex) throws I2NPMessageException {
if ( (_tunnelId == null) || ( (_msg == null) && (_msgData == null) ) ) {
_log.log(Log.CRIT, "failing to write out gateway message");
throw new I2NPMessageException("Not enough data to write out (id=" + _tunnelId + " data=" + _msg + ")");
}
DataHelper.toLong(out, curIndex, 4, _tunnelId.getTunnelId());
curIndex += 4;
synchronized (this) {
if (_msgData == null) {
_msgData = _msg.toByteArray();
_msg = null;
}
}
DataHelper.toLong(out, curIndex, 2, _msgData.length);
curIndex += 2;
// where is this coming from?
if (curIndex + _msgData.length > out.length) {
String txt = "output buffer too small idx: " + curIndex + " len: " + _msgData.length + " outlen: " + out.length;
_log.error(txt);
throw new I2NPMessageException(txt);
}
System.arraycopy(_msgData, 0, out, curIndex, _msgData.length);
curIndex += _msgData.length;
return curIndex;
}
public void readMessage(byte data[], int offset, int dataSize, int type) throws I2NPMessageException {
//I2NPMessageHandler h = new I2NPMessageHandler(_context);
//readMessage(data, offset, dataSize, type, h);
readMessage(data, offset, dataSize, type, null);
}
/**
* Note that for efficiency at the IBGW, this does not fully deserialize the included
* I2NP Message. It just puts it in an UnknownI2NPMessage.
*
* @param handler unused, may be null
*/
@Override
public void readMessage(byte data[], int offset, int dataSize, int type, I2NPMessageHandler handler) throws I2NPMessageException {
if (type != MESSAGE_TYPE) throw new I2NPMessageException("Message type is incorrect for this message");
int curIndex = offset;
_tunnelId = new TunnelId(DataHelper.fromLong(data, curIndex, 4));
curIndex += 4;
if (_tunnelId.getTunnelId() <= 0)
throw new I2NPMessageException("Invalid tunnel Id " + _tunnelId);
int len = (int) DataHelper.fromLong(data, curIndex, 2);
curIndex += 2;
if (len <= 1 || curIndex + len > data.length || len > dataSize - 6)
throw new I2NPMessageException("I2NP length in TGM: " + len +
" but remaining bytes: " + Math.min(data.length - curIndex, dataSize - 6));
// OLD WAY full message parsing and instantiation
//handler.readMessage(data, curIndex);
//_msg = handler.lastRead();
//if (_msg == null)
// throw new I2NPMessageException("impossible? message read has no payload?!");
// NEW WAY save lots of effort at the IBGW by reading as an UnknownI2NPMessage instead
// This will save a lot of object churn and processing,
// primarily for unencrypted msgs (V)TBRM, DatabaseStoreMessage, and DSRMs.
// DatabaseStoreMessages in particluar are intensive for readBytes()
// since the RI is decompressed.
// For a zero-hop IB tunnel, where we do need the real thing,
// it is converted to a real message class in TunnelGatewayZeroHop
// using UnknownI2NPMessage.convert() in TunnelGatewayZeroHop.
// We also skip processing the checksum as it's covered by the TGM checksum.
// If a zero-hop, the checksum will be verified in convert().
int utype = data[curIndex++] & 0xff;
UnknownI2NPMessage umsg = new UnknownI2NPMessage(_context, utype);
umsg.readBytes(data, utype, curIndex);
_msg = umsg;
}
public int getType() { return MESSAGE_TYPE; }
@Override
public int hashCode() {
return DataHelper.hashCode(getTunnelId()) +
DataHelper.hashCode(_msg);
}
@Override
public boolean equals(Object object) {
if ( (object != null) && (object instanceof TunnelGatewayMessage) ) {
TunnelGatewayMessage msg = (TunnelGatewayMessage)object;
return DataHelper.eq(getTunnelId(),msg.getTunnelId()) &&
DataHelper.eq(_msgData, msg._msgData) &&
DataHelper.eq(getMessage(), msg.getMessage());
} else {
return false;
}
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
buf.append("[TunnelGatewayMessage:");
buf.append(" MessageId: ").append(getUniqueId());
buf.append(" Tunnel ID: ").append(getTunnelId());
buf.append(" Message: ").append(_msg);
buf.append("]");
return buf.toString();
}
}
