private void receivePing(Packet packet) {
boolean ok = packet.verifySignature(_context, packet.getOptionalFrom(), null);
if (!ok) {
if (_log.shouldLog(Log.WARN)) {
if (packet.getOptionalFrom() == null)
_log.warn(
"Ping with no from (flagged? " + packet.isFlagSet(Packet.FLAG_FROM_INCLUDED) + ")");
else if (packet.getOptionalSignature() == null)
_log.warn(
"Ping with no signature (flagged? "
+ packet.isFlagSet(Packet.FLAG_SIGNATURE_INCLUDED)
+ ")");
else
_log.warn(
"Forged ping, discard (from="
+ packet.getOptionalFrom().calculateHash().toBase64()
+ " sig="
+ packet.getOptionalSignature().toBase64()
+ ")");
}
} else {
PacketLocal pong = new PacketLocal(_context, packet.getOptionalFrom());
pong.setFlag(Packet.FLAG_ECHO, true);
pong.setFlag(Packet.FLAG_SIGNATURE_INCLUDED, false);
pong.setReceiveStreamId(packet.getSendStreamId());
_manager.getPacketQueue().enqueue(pong);
}
}
private void sendReset(Packet packet) {
boolean ok = packet.verifySignature(_context, packet.getOptionalFrom(), null);
if (!ok) {
if (_log.shouldLog(Log.WARN))
_log.warn("Received a spoofed SYN packet: they said they were " + packet.getOptionalFrom());
return;
}
PacketLocal reply = new PacketLocal(_context, packet.getOptionalFrom());
reply.setFlag(Packet.FLAG_RESET);
reply.setFlag(Packet.FLAG_SIGNATURE_INCLUDED);
reply.setAckThrough(packet.getSequenceNum());
reply.setSendStreamId(packet.getReceiveStreamId());
reply.setReceiveStreamId(0);
reply.setOptionalFrom(_manager.getSession().getMyDestination());
if (_log.shouldLog(Log.DEBUG)) _log.debug("Sending RST: " + reply + " because of " + packet);
// this just sends the packet - no retries or whatnot
_manager.getPacketQueue().enqueue(reply);
}
/**
* This sends a reset back to the place this packet came from. If the packet has no 'optional
* from' or valid signature, this does nothing. This is not associated with a connection, so no
* con stats are updated.
*/
private void sendReset(Packet packet) {
Destination from = packet.getOptionalFrom();
if (from == null) return;
boolean ok = packet.verifySignature(_context, from, null);
if (!ok) {
if (_log.shouldLog(Log.WARN))
_log.warn("Can't send reset after recv spoofed packet: " + packet);
return;
}
PacketLocal reply = new PacketLocal(_context, from);
reply.setFlag(Packet.FLAG_RESET);
reply.setFlag(Packet.FLAG_SIGNATURE_INCLUDED);
reply.setSendStreamId(packet.getReceiveStreamId());
reply.setReceiveStreamId(packet.getSendStreamId());
reply.setOptionalFrom(_manager.getSession().getMyDestination());
// this just sends the packet - no retries or whatnot
_manager.getPacketQueue().enqueue(reply);
}
/**
* Receive an incoming connection (built from a received SYN) 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.
*
* @param timeoutMs max amount of time to wait for a connection (if less than 1ms, wait
* indefinitely)
* @return connection received, or null if there was a timeout or the handler was shut down
*/
public Connection accept(long timeoutMs) {
if (_log.shouldLog(Log.DEBUG)) _log.debug("Accept(" + timeoutMs + ") called");
long expiration = timeoutMs + _context.clock().now();
while (true) {
if ((timeoutMs > 0) && (expiration < _context.clock().now())) return null;
if (!_active) {
// fail all the ones we had queued up
while (true) {
Packet packet = _synQueue.poll(); // fails immediately if empty
if (packet == null || packet.getOptionalDelay() == PoisonPacket.POISON_MAX_DELAY_REQUEST)
break;
sendReset(packet);
}
return null;
}
Packet syn = null;
while (_active && syn == null) {
if (_log.shouldLog(Log.DEBUG))
_log.debug(
"Accept(" + timeoutMs + "): active=" + _active + " queue: " + _synQueue.size());
if (timeoutMs <= 0) {
try {
syn = _synQueue.take(); // waits forever
} catch (InterruptedException ie) {
} // { break;}
} else {
long remaining = expiration - _context.clock().now();
// (dont think this applies anymore for LinkedBlockingQueue)
// BUGFIX
// The specified amount of real time has elapsed, more or less.
// If timeout is zero, however, then real time is not taken into consideration
// and the thread simply waits until notified.
if (remaining < 1) break;
try {
syn = _synQueue.poll(remaining, TimeUnit.MILLISECONDS); // waits the specified time max
} catch (InterruptedException ie) {
}
break;
}
}
if (syn != null) {
if (syn.getOptionalDelay() == PoisonPacket.POISON_MAX_DELAY_REQUEST) return null;
// deal with forged / invalid syn packets in _manager.receiveConnection()
// Handle both SYN and non-SYN packets in the queue
if (syn.isFlagSet(Packet.FLAG_SYNCHRONIZE)) {
// We are single-threaded here, so this is
// a good place to check for dup SYNs and drop them
Destination from = syn.getOptionalFrom();
if (from == null) {
if (_log.shouldLog(Log.WARN)) _log.warn("Dropping SYN packet with no FROM: " + syn);
// drop it
continue;
}
Connection oldcon = _manager.getConnectionByOutboundId(syn.getReceiveStreamId());
if (oldcon != null) {
// His ID not guaranteed to be unique to us, but probably is...
// only drop it on a destination match too
if (from.equals(oldcon.getRemotePeer())) {
if (_log.shouldLog(Log.WARN)) _log.warn("Dropping dup SYN: " + syn);
continue;
}
}
Connection con = _manager.receiveConnection(syn);
if (con != null) return con;
} else {
reReceivePacket(syn);
// ... and keep looping
}
}
// keep looping...
}
}