/*
* @param max per-peer, 0 for unlimited
* @param totalMax for all peers, 0 for unlimited
* @param period ms
*/
ConnThrottler(int max, int totalMax, long period) {
_max = max;
_totalMax = totalMax;
this.counter = new ObjectCounter<Hash>();
_currentTotal = new AtomicInteger();
SimpleScheduler.getInstance().addPeriodicEvent(new Cleaner(), period);
}
/**
* Non-SYN packets with a zero SendStreamID may also be queued here so that they don't get thrown
* away while the SYN packet before it is queued.
*
* <p>Additional overload protection may be required here... We don't have a 3-way handshake, so
* the SYN fully opens a connection. Does that make us more or less vulnerable to SYN flooding?
*/
public void receiveNewSyn(Packet packet) {
if (!_active) {
if (_log.shouldLog(Log.WARN)) _log.warn("Dropping new SYN request, as we're not listening");
if (packet.isFlagSet(Packet.FLAG_SYNCHRONIZE)) sendReset(packet);
return;
}
if (_log.shouldLog(Log.INFO))
_log.info("Receive new SYN: " + packet + ": timeout in " + _acceptTimeout);
// also check if expiration of the head is long past for overload detection with peek() ?
boolean success = _synQueue.offer(packet); // fail immediately if full
if (success) {
SimpleScheduler.getInstance().addEvent(new TimeoutSyn(packet), _acceptTimeout);
} else {
if (_log.shouldLog(Log.WARN)) _log.warn("Dropping new SYN request, as the queue is full");
if (packet.isFlagSet(Packet.FLAG_SYNCHRONIZE)) sendReset(packet);
}
}