/** Performs the probe asynchronously. */
private void sendProbe() {
final NameServicesChannelMessage message = new NameServicesChannelMessage();
message.agent = Nodel.getAgent();
List<String> discoveryList = new ArrayList<String>(1);
discoveryList.add("*");
List<String> typesList = new ArrayList<String>(2);
typesList.add("tcp");
typesList.add("http");
message.discovery = discoveryList;
message.types = typesList;
_lastProbe.set(System.nanoTime());
// IO is involved so use a thread-pool
_threadPool.execute(
new Runnable() {
@Override
public void run() {
sendMessage(_sendSocket, s_sendSocketLabel, _groupSocketAddress, message);
// check if hard links (direct "multicasting") are enabled for some hosts
if (_hardLinksAddresses != null && _hardLinksSocket != null) {
for (InetSocketAddress socketAddress : _hardLinksAddresses) {
sendMessage(_hardLinksSocket, s_hardLinksSocketlabel, socketAddress, message);
}
}
}
});
}
/**
* Turns the list of addresses into "resolved" InetSocketAddresses. (should only be called once)
*/
private List<InetSocketAddress> composeHardLinksSocketAddresses() {
List<InetAddress> addresses = Nodel.getHardLinksAddresses();
if (addresses.size() <= 0) return null;
List<InetSocketAddress> socketAddresses = new ArrayList<InetSocketAddress>();
for (InetAddress address : addresses)
socketAddresses.add(new InetSocketAddress(address, MDNS_PORT));
// at least one address is enabled, so initialise a general purpose UDP socket and
// receiver thread.
Thread thread =
new Thread(
new Runnable() {
@Override
public void run() {
hardLinksReceiverThreadMain();
}
},
s_hardLinksSocketlabel);
thread.setDaemon(true);
thread.start();
return socketAddresses;
}
/** Used to monitor address changes on the the interface. */
private void handleInterfaceCheck() {
try {
int port = super.getAdvertisementPort();
if (port < 0) {
// can't compose a nodel address yet
_logger.info("(nodel server port still not available; will wait.)");
return;
}
InetAddress localIPv4Address = getLocalIPv4Address();
String nodelAddress = "tcp://" + localIPv4Address.getHostAddress() + ":" + port;
if (nodelAddress.equals(_nodelAddress))
// nothing to do
return;
// the address has changed so should update advertisements
_logger.info(
"An address change has been detected. previous={}, current={}",
_nodelAddress,
nodelAddress);
_nodelAddress = "tcp://" + localIPv4Address.getHostAddress() + ":" + port;
_httpAddress =
"http://"
+ localIPv4Address.getHostAddress()
+ ":"
+ Nodel.getHTTPPort()
+ Nodel.getHTTPSuffix();
Nodel.updateHTTPAddress(_httpAddress);
synchronized (_lock) {
// recycle receiver which will in turn recycle sender
_recycleReceiver = true;
// "signal" thread
Stream.safeClose(_receiveSocket);
}
} catch (Exception exc) {
_logger.warn("'handleInterfaceCheck' did not complete cleanly; ignoring for now.", exc);
}
} // (method)
/** Used for registering / unregistering nodes for discovery / lookup purposes. */
public class NodelAutoDNS extends AutoDNS {
/** IPv4 multicast group */
public static final String MDNS_GROUP = "224.0.0.252";
/** IPv6 multicast group (not used here but reserved) */
public static final String MDNS_GROUP_IPV6 = "FF02::FB";
/** Multicast port */
public static final int MDNS_PORT = 5354;
/** The period between probes when actively probing. (millis) */
private static final int PROBE_PERIOD = 45000;
/** Expiry time (allow for at least one missing probe response) */
private static final long STALE_TIME = 2 * PROBE_PERIOD + 10000;
/**
* How long to allow the multicast receiver to be silent. Will reinitialise socket as a
* precaution.
*/
private static final int SILENCE_TOLERANCE = 3 * PROBE_PERIOD + 10000;
/** (instrumentation) */
private static AtomicLong s_multicastOutOps = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_multicastOutOpsMeasurement =
new AtomicLongMeasurementProvider(s_multicastOutOps);
/** Multicast in operations. */
public static AtomicLongMeasurementProvider MulticastOutOpsMeasurement() {
return s_multicastOutOpsMeasurement;
}
/** (instrumentation) */
private static AtomicLong s_multicastOutData = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_multicastOutDataMeasurement =
new AtomicLongMeasurementProvider(s_multicastOutData);
/** Multicast out data. */
public static AtomicLongMeasurementProvider MulticastOutDataMeasurement() {
return s_multicastOutDataMeasurement;
}
/** (instrumentation) */
private static AtomicLong s_multicastInOps = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_multicastInOpsMeasurement =
new AtomicLongMeasurementProvider(s_multicastInOps);
/** Multicast in operations. */
public static AtomicLongMeasurementProvider MulticastInOpsMeasurement() {
return s_multicastInOpsMeasurement;
}
/** (instrumentation) */
private static AtomicLong s_multicastInData = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_multicastInDataMeasurement =
new AtomicLongMeasurementProvider(s_multicastInData);
/** Multicast in data. */
public static AtomicLongMeasurementProvider MulticastInDataMeasurement() {
return s_multicastInDataMeasurement;
}
/** (instrumentation) */
private static AtomicLong s_unicastOutOps = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_unicastOutOpsMeasurement =
new AtomicLongMeasurementProvider(s_unicastOutOps);
/** Unicast in operations. */
public static AtomicLongMeasurementProvider UnicastOutOpsMeasurement() {
return s_unicastOutOpsMeasurement;
}
/** (instrumentation) */
private static AtomicLong s_unicastOutData = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_unicastOutDataMeasurement =
new AtomicLongMeasurementProvider(s_unicastOutData);
/** Unicast out data. */
public static AtomicLongMeasurementProvider UnicastOutDataMeasurement() {
return s_unicastOutDataMeasurement;
}
/** (instrumentation) */
private static AtomicLong s_unicastInOps = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_unicastInOpsMeasurement =
new AtomicLongMeasurementProvider(s_unicastInOps);
/** Unicast in operations. */
public static AtomicLongMeasurementProvider UnicastInOpsMeasurement() {
return s_unicastInOpsMeasurement;
}
/** (instrumentation) */
private static AtomicLong s_unicastInData = new AtomicLong();
/** (instrumentation) */
private static AtomicLongMeasurementProvider s_unicastInDataMeasurement =
new AtomicLongMeasurementProvider(s_unicastInData);
/** Unicast in data. */
public static AtomicLongMeasurementProvider UnicastInDataMeasurement() {
return s_unicastInDataMeasurement;
}
/**
* Returns '127.0.0.99' as a dummy address, normally when no network services are available. Using
* '99' to know what's going on if it happens to come up.
*/
private static InetAddress s_dummyInetAddress = parseNumericalIPAddress("127.0.0.99");
/** (logging) */
private Logger _logger = LoggerFactory.getLogger(NodelAutoDNS.class);
/** General purpose lock / signal. */
private Object _serverLock = new Object();
/** General purpose lock / signal. */
private Object _clientLock = new Object();
/** Used to micro-stagger responses. */
private Random _random = new Random();
/** Thread-pool for IO operations. */
private ThreadPool _threadPool = new ThreadPool("Discovery", 24);
/** This class' timer thread. */
private Timers _timerThread = new Timers("Discovery");
/** The thread to receive the multicast data. */
private Thread _multicastHandlerThread;
/** The thread to receive the multicast data. */
private Thread _unicastHandlerThread;
/** (for graceful clean up) */
private List<TimerTask> _timers = new ArrayList<TimerTask>();
/** (permanently latches false) */
private volatile boolean _enabled = true;
/** (used in 'incomingQueue') */
private class QueueEntry {
/** For logging purposes */
public final String source;
/** The packet */
public final DatagramPacket packet;
public QueueEntry(String source, DatagramPacket packet) {
this.source = source;
this.packet = packet;
}
}
/** The incoming queue. (self locked) */
private Queue<QueueEntry> _incomingQueue = new LinkedList<QueueEntry>();
/** Used to avoid unnecessary thread overlapping. */
private boolean _isProcessingIncomingQueue = false;
/** Incoming queue processor runnable. */
private Runnable _incomingQueueProcessor =
new Runnable() {
@Override
public void run() {
processIncomingPacketQueue();
}
};
/** Used in '_services'. */
private class ServiceItem {
SimpleName _name;
public ServiceItem(SimpleName name) {
_name = name;
}
} // (class)
/** Holds the registered service items. */
private ConcurrentMap<SimpleName, ServiceItem> _services =
new ConcurrentHashMap<SimpleName, ServiceItem>();
/** Holds the collected advertisements. */
private ConcurrentMap<SimpleName, AdvertisementInfo> _advertisements =
new ConcurrentHashMap<SimpleName, AdvertisementInfo>();
/** (as an InetAddress; will never be null) */
private InetAddress _group = parseNumericalIPAddress(MDNS_GROUP);
/** (as an InetSocketAddress (with port); will never be null) */
private InetSocketAddress _groupSocketAddress = new InetSocketAddress(_group, MDNS_PORT);
/**
* Whether or not we're probing for client. It will probe on start up and then deactivate. e.g.
* 'list' is called. (nanos)
*/
private AtomicLong _lastList = new AtomicLong(System.nanoTime());
/** The last time a probe occurred. (nanos) */
private AtomicLong _lastProbe = new AtomicLong(0);
/**
* Whether or not client resolution is being used. This affects whether polling should take place.
* (one way switch)
*/
private volatile boolean _usingResolution = false;
/**
* The time before probing can be suspended if there haven't been any recent 'list' or 'resolve'
* operation. 5 minutes.
*
* <p>(millis)
*/
private static final long LIST_ACTIVITY_PERIOD = 5 * 60 * 1000;
/** General purpose lock for sendSocket, receiveSocket, enabled, recycle*flag */
private Object _lock = new Object();
/** For multicast sends and unicast receives on arbitrary port. (locked around 'lock') */
private MulticastSocket _sendSocket;
/** (socket label) */
private static final String s_sendSocketLabel = "[multicastSender_unicastSenderReceiver]";
/** (flag; locked around 'lock') */
private boolean _recycleSender;
/** For multicast receives on the MDNS port. */
private MulticastSocket _receiveSocket;
/** (socket label) */
private static String s_receiveSocketlabel = "[multicastReceiver]";
/** (flag; locked around 'lock') */
private boolean _recycleReceiver;
/** Used if direct "multicast" (using unicast) is enabled. */
private DatagramSocket _hardLinksSocket;
/** (socket label) */
private static String s_hardLinksSocketlabel = "[unicastHardLinksSenderReceiver]";
/** (will never be null after being set) */
private String _nodelAddress;
/** Will be a valid address. */
private String _httpAddress =
"http://"
+ getLocalIPv4Address().getHostAddress()
+ ":"
+ Nodel.getHTTPPort()
+ Nodel.getHTTPSuffix();
/**
* Holds a safe list of resolved addresses and ports that should be "directly" multicast to (i.e.
* using unicast). Can be used if multicasting is unreliable or inconvenient. (is either null or
* has at least one element)
*/
private List<InetSocketAddress> _hardLinksAddresses = composeHardLinksSocketAddresses();
/**
* Returns immediately.
*
* <p>(Private constructor)
*/
private NodelAutoDNS() {
// (no blocking code can be here)
// create the receiver thread and start it
_multicastHandlerThread =
new Thread(
new Runnable() {
@Override
public void run() {
multicastReceiverThreadMain();
}
},
"autodns_multicastreceiver");
_multicastHandlerThread.setDaemon(true);
_multicastHandlerThread.start();
// create the receiver thread and start it
_unicastHandlerThread =
new Thread(
new Runnable() {
@Override
public void run() {
unicastReceiverThreadMain();
}
},
"autodns_unicastreceiver");
_unicastHandlerThread.setDaemon(true);
_unicastHandlerThread.start();
// kick off the client prober to start
// after 10s - 15s (randomly chosen)
_timers.add(
_timerThread.schedule(
new TimerTask() {
@Override
public void run() {
handleProbeTimer();
}
},
(long) (10000 + _random.nextDouble() * 5000),
PROBE_PERIOD));
// kick off the cleanup tasks timer
_timers.add(
_timerThread.schedule(
new TimerTask() {
@Override
public void run() {
handleCleanupTimer();
}
},
60000,
60000));
;
// monitor interface changes after 10s delay, then every 2 mins
_timers.add(
_timerThread.schedule(
new TimerTask() {
@Override
public void run() {
handleInterfaceCheck();
}
},
10000,
120000));
_logger.info(
"Auto discovery threads and timers started. probePeriod:{}, stalePeriodAllowed:{}",
DateTimes.formatShortDuration(PROBE_PERIOD),
DateTimes.formatShortDuration(STALE_TIME));
} // (init)
/** Creates a new socket, cleaning up if anything goes wrong in the process */
private MulticastSocket createMulticastSocket(String label, InetAddress intf, int port)
throws Exception {
MulticastSocket socket = null;
try {
_logger.info(
"Preparing {} socket. interface:{}, port:{}, group:{}",
label,
(intf == null ? "default" : intf),
(port == 0 ? "any" : port),
_group);
// in previous versions the interface was selected using constructor instead of
// 'socket.setInterface(intf)'
// but that uncovered side-effect in OSX which caused 'cannot assign address' Java bug
socket = new MulticastSocket(port); // (port '0' means any port)
if (intf != null) socket.setInterface(intf);
// join the multicast group
socket.joinGroup(_group);
_logger.info("{} ready. localAddr:{}", label, socket.getLocalSocketAddress());
return socket;
} catch (Exception exc) {
Stream.safeClose(socket);
throw exc;
}
}
/** (thread entry-point) */
private void multicastReceiverThreadMain() {
while (_enabled) {
MulticastSocket socket = null;
try {
synchronized (_lock) {
// clear flag regardless
_recycleReceiver = false;
}
socket = createMulticastSocket(s_receiveSocketlabel, s_interface, MDNS_PORT);
synchronized (_lock) {
// make sure not flagged since reset
if (_recycleReceiver) {
Stream.safeClose(socket);
continue;
}
_receiveSocket = socket;
}
while (_enabled) {
DatagramPacket dp = UDPPacketRecycleQueue.instance().getReadyToUsePacket();
// ('returnPacket' will be called in 'catch' or later after use in thread-pool)
try {
socket.receive(dp);
} catch (Exception exc) {
UDPPacketRecycleQueue.instance().returnPacket(dp);
throw exc;
}
InetAddress recvAddr = dp.getAddress();
if (recvAddr.isMulticastAddress()) {
s_multicastInData.addAndGet(dp.getLength());
s_multicastInOps.incrementAndGet();
} else {
s_unicastInData.addAndGet(dp.getLength());
s_unicastInOps.incrementAndGet();
}
// check whether it's external i.e. completely different IP address
// (local multicasting would almost always be reliable)
MulticastSocket otherLocal = _sendSocket;
boolean isLocal = (otherLocal != null && recvAddr.equals(otherLocal.getLocalAddress()));
// update counter which is used to detect silence
if (!isLocal) _lastExternalMulticastPacket = System.nanoTime();
enqueueForProcessing(dp, s_receiveSocketlabel);
} // (inner while)
} catch (Exception exc) {
// (timeouts and general IO problems)
// clean up regardless
Stream.safeClose(socket);
synchronized (_lock) {
if (!_enabled) break;
if (_recycleReceiver)
_logger.info(s_receiveSocketlabel + " was gracefully closed. Will reinitialise...");
else
_logger.warn(
s_receiveSocketlabel
+ " receive failed; this may be a transitional condition. Will reinitialise... message was '"
+ exc.toString()
+ "'");
// set flag
_recycleSender = true;
// "signal" other thread
Stream.safeClose(_sendSocket);
// stagger retry
Threads.waitOnSync(_lock, 333);
}
}
} // (outer while)
_logger.info("This thread has run to completion.");
} // (method)
/** (thread entry-point) */
private void unicastReceiverThreadMain() {
while (_enabled) {
MulticastSocket socket = null;
try {
synchronized (_lock) {
// clear flag regardless
_recycleSender = false;
}
socket = createMulticastSocket(s_sendSocketLabel, s_interface, 0);
// make sure a recycle request hasn't since occurred
synchronized (_lock) {
if (_recycleSender) {
Stream.safeClose(socket);
continue;
}
_sendSocket = socket;
}
while (_enabled) {
DatagramPacket dp = UDPPacketRecycleQueue.instance().getReadyToUsePacket();
try {
socket.receive(dp);
} catch (Exception exc) {
UDPPacketRecycleQueue.instance().returnPacket(dp);
throw exc;
}
if (dp.getAddress().isMulticastAddress()) {
s_multicastInData.addAndGet(dp.getLength());
s_multicastInOps.incrementAndGet();
} else {
s_unicastInData.addAndGet(dp.getLength());
s_unicastInOps.incrementAndGet();
}
enqueueForProcessing(dp, s_sendSocketLabel);
} // (inner while)
} catch (Exception exc) {
boolean wasClosed = (socket != null && socket.isClosed());
// clean up regardless
Stream.safeClose(socket);
synchronized (_lock) {
if (!_enabled) break;
if (wasClosed)
_logger.info(
s_sendSocketLabel + " was signalled to gracefully close. Will reinitialise...");
else _logger.warn(s_sendSocketLabel + " receive failed; will reinitialise...", exc);
// stagger retry
Threads.waitOnSync(_lock, 333);
}
}
} // (outer while)
_logger.info("This thread has run to completion.");
}
private void enqueueForProcessing(DatagramPacket dp, String label) {
// place it in the queue and make it process if necessary
synchronized (_incomingQueue) {
QueueEntry qe = new QueueEntry(label, dp);
_incomingQueue.add(qe);
// kick off the other thread to process the queue
// (otherwise the thread will already be processing the queue)
if (!_isProcessingIncomingQueue) {
_isProcessingIncomingQueue = true;
_threadPool.execute(_incomingQueueProcessor);
}
}
}
/** Processes whatever's in the queue. */
private void processIncomingPacketQueue() {
while (_enabled) {
QueueEntry entry;
synchronized (_incomingQueue) {
if (_incomingQueue.size() <= 0) {
// nothing left, so clear flag and return
_isProcessingIncomingQueue = false;
return;
}
entry = _incomingQueue.remove();
}
DatagramPacket dp = entry.packet;
String source = entry.source;
try {
// parse packet
NameServicesChannelMessage message = this.parsePacket(dp);
// handle message
this.handleIncomingMessage(source, (InetSocketAddress) dp.getSocketAddress(), message);
} catch (Exception exc) {
if (!_enabled) break;
// log nested exception summary instead of stack-trace dump
_logger.warn(
"{} while handling received packet from {}: {}",
source,
dp.getSocketAddress(),
Exceptions.formatExceptionGraph(exc));
} finally {
// make sure the packet is returned
UDPPacketRecycleQueue.instance().returnPacket(entry.packet);
}
} // (while)
}
private boolean _suppressProbeLog = false;
/** The last time an external multicast packet was received. (nano-based) */
private volatile long _lastExternalMulticastPacket = System.nanoTime();
/** The client timer; determines whether probing is actually necessary (timer entry-point) */
private void handleProbeTimer() {
if (_usingResolution) {
// client names are being resolved, so stay probing
_suppressProbeLog = false;
sendProbe();
} else {
// the time difference in millis
long listDiff = (System.nanoTime() - _lastList.get()) / 1000000L;
if (listDiff < LIST_ACTIVITY_PERIOD) {
_suppressProbeLog = false;
sendProbe();
} else {
if (!_suppressProbeLog) {
_logger.info(
"Probing is paused because it has been more than {} since a 'list' or 'resolve' (total {}).",
DateTimes.formatShortDuration(LIST_ACTIVITY_PERIOD),
DateTimes.formatShortDuration(listDiff));
}
_suppressProbeLog = true;
}
}
}
/** Performs the probe asynchronously. */
private void sendProbe() {
final NameServicesChannelMessage message = new NameServicesChannelMessage();
message.agent = Nodel.getAgent();
List<String> discoveryList = new ArrayList<String>(1);
discoveryList.add("*");
List<String> typesList = new ArrayList<String>(2);
typesList.add("tcp");
typesList.add("http");
message.discovery = discoveryList;
message.types = typesList;
_lastProbe.set(System.nanoTime());
// IO is involved so use a thread-pool
_threadPool.execute(
new Runnable() {
@Override
public void run() {
sendMessage(_sendSocket, s_sendSocketLabel, _groupSocketAddress, message);
// check if hard links (direct "multicasting") are enabled for some hosts
if (_hardLinksAddresses != null && _hardLinksSocket != null) {
for (InetSocketAddress socketAddress : _hardLinksAddresses) {
sendMessage(_hardLinksSocket, s_hardLinksSocketlabel, socketAddress, message);
}
}
}
});
}
/** Handle clean-up tasks (timer entry-point) */
private void handleCleanupTimer() {
long currentTime = System.nanoTime();
reapStaleRecords(currentTime);
recycleReceiverIfNecessary(currentTime);
} // (method)
/** Checks for stale records and removes them. */
private void reapStaleRecords(long currentTime) {
LinkedList<AdvertisementInfo> toRemove = new LinkedList<AdvertisementInfo>();
synchronized (_clientLock) {
for (AdvertisementInfo adInfo : _advertisements.values()) {
long timeDiff = (currentTime / 1000000) - adInfo.timeStamp;
if (timeDiff > STALE_TIME) toRemove.add(adInfo);
}
// reap if necessary
if (toRemove.size() > 0) {
StringBuilder sb = new StringBuilder();
for (AdvertisementInfo adInfo : toRemove) {
if (sb.length() > 0) sb.append(",");
_advertisements.remove(adInfo.name);
sb.append(adInfo.name);
}
_logger.info(
"{} stale record{} removed. [{}]",
toRemove.size(),
toRemove.size() == 1 ? " was" : "s were",
sb.toString());
}
}
} // (method)
/**
* Check if the main receiver has been silent for some time so recycle the socket for best
* resilience.
*/
private void recycleReceiverIfNecessary(long currentTime) {
long timeDiff = (currentTime - _lastExternalMulticastPacket) / 1000000;
if (timeDiff > SILENCE_TOLERANCE) {
_logger.info(
"There appears to be external silence on the multicast receiver (this may or may not be expected); the socket will be recycled to ensure resilience.");
synchronized (_lock) {
// recycle receiver which will in turn recycle sender
_recycleReceiver = true;
// "signal" the other thread
Stream.safeClose(_receiveSocket);
}
}
}
/** Parses the incoming packet. */
private NameServicesChannelMessage parsePacket(DatagramPacket dp) {
String packetString = new String(dp.getData(), 0, dp.getLength(), UTF8Charset.instance());
return (NameServicesChannelMessage)
Serialisation.coerceFromJSON(NameServicesChannelMessage.class, packetString);
}
/** One responder per recipient at any stage. */
private class Responder {
public InetSocketAddress _recipient;
public LinkedList<ServiceItem> _serviceSet;
private Iterator<ServiceItem> _serviceIterator;
public Responder(InetSocketAddress recipient) {
_recipient = recipient;
synchronized (_serverLock) {
// get a snap-shot of the service values
_serviceSet = new LinkedList<ServiceItem>(_services.values());
}
// the service iterator
_serviceIterator = _serviceSet.iterator();
}
/**
* Starts the responder. Wait a random amount of time to before actually sending anything.
* Staggered responses assists with receiver buffer management by the remote receivers.
*/
public void start(int randomResponseDelay) {
// use a random minimum delay of 333ms
int delay = 333;
if (randomResponseDelay > 333) delay = randomResponseDelay;
int timeToWait = _random.nextInt(delay);
_timerThread.schedule(
new TimerTask() {
@Override
public void run() {
completeResponse();
}
},
timeToWait);
}
/** Complete the necessary response, also a timer entry-point. */
private void completeResponse() {
// prepare a message
final NameServicesChannelMessage message = new NameServicesChannelMessage();
message.present = new ArrayList<String>();
// try keep the packets relatively small by roughly guessing how much space
// its JSON advertisement packet might take up
// account for "present"...
// and
// "addresses":["tcp://136.154.27.100:65017","http://136.154.27.100:8085/index.htm?node=%NODE%"]
// so start off with approx. 110 chars
long roughTotalSize = 110;
while (_serviceIterator.hasNext()) {
ServiceItem si = _serviceIterator.next();
String name = si._name.getOriginalName();
// calculate size to be the name, two inverted-commas, and a comma and a possible space in
// between.
int size = name.length() + 4;
roughTotalSize += size;
message.present.add(name);
// make sure we're not going anywhere near UDP MTU (64K),
// in fact, squeeze them into packets similar to size of Ethernet MTU (~1400 MTU)
if (roughTotalSize > 1200) break;
} // (while)
message.addresses = new ArrayList<String>();
message.addresses.add(_nodelAddress);
message.addresses.add(_httpAddress);
// IO is involved so use thread-pool
// (and only send if the 'present' list is not empty)
if (message.present.size() > 0) {
_threadPool.execute(
new Runnable() {
@Override
public void run() {
sendMessage(_sendSocket, s_sendSocketLabel, _recipient, message);
}
});
}
// do we need this completed in the very near future?
// if so, space out by at least 333ms.
if (_serviceIterator.hasNext()) {
_timerThread.schedule(
new TimerTask() {
@Override
public void run() {
completeResponse();
}
},
333);
} else {
synchronized (_responders) {
_responders.remove(_recipient);
}
}
} // (method)
} // (class)
/** Sends the message to a recipient */
private void sendMessage(
DatagramSocket socket,
String label,
InetSocketAddress to,
NameServicesChannelMessage message) {
if (isSameSocketAddress(socket, to))
_logger.info("{} sending message. to=self, message={}", label, message);
else _logger.info("{} sending message. to={}, message={}", label, to, message);
if (socket == null) {
_logger.info("{} is not available yet; ignoring send request.", label);
return;
}
// convert into bytes
String json = Serialisation.serialise(message);
byte[] bytes = json.getBytes(UTF8Charset.instance());
DatagramPacket packet = new DatagramPacket(bytes, bytes.length);
packet.setSocketAddress(to);
try {
socket.send(packet);
if (to.getAddress().isMulticastAddress()) {
s_multicastOutData.addAndGet(bytes.length);
s_multicastOutOps.incrementAndGet();
} else {
s_unicastOutData.addAndGet(bytes.length);
s_unicastOutOps.incrementAndGet();
}
} catch (IOException exc) {
if (!_enabled) return;
if (socket.isClosed())
_logger.info(s_sendSocketLabel + " send() ignored as socket is being recycled.");
else _logger.warn(s_sendSocketLabel + " send() failed. ", exc);
}
} // (method)
/** The map of responders by recipient address. */
private ConcurrentMap<SocketAddress, Responder> _responders =
new ConcurrentHashMap<SocketAddress, Responder>();
/** Handles a complete packet from the socket. */
private void handleIncomingMessage(
String label, InetSocketAddress from, NameServicesChannelMessage message) {
if (isSameSocketAddress(_sendSocket, from))
_logger.info("{} message arrived. from=self, message={}", label, message);
else _logger.info("{} message arrived. from={}, message={}", label, from, message);
// discovery request?
if (message.discovery != null) {
// create a responder if one isn't already active
if (_nodelAddress == null) {
_logger.info("(will not respond; nodel server port still not available)");
return;
}
synchronized (_responders) {
if (!_responders.containsKey(from)) {
Responder responder = new Responder(from);
_responders.put(from, responder);
int delay = message.delay == null ? 0 : message.delay.intValue();
responder.start(delay);
}
}
} else if (message.present != null && message.addresses != null) {
for (String name : message.present) {
synchronized (_clientLock) {
SimpleName node = new SimpleName(name);
AdvertisementInfo ad = _advertisements.get(node);
if (ad == null) {
ad = new AdvertisementInfo();
ad.name = node;
_advertisements.put(node, ad);
}
// refresh the time stamp and update the address
ad.timeStamp = System.nanoTime() / 1000000;
ad.addresses = message.addresses;
}
}
}
} // (method)
@Override
public NodeAddress resolveNodeAddress(SimpleName node) {
// indicate client resolution is being used
_usingResolution = true;
AdvertisementInfo adInfo = _advertisements.get(node);
if (adInfo != null) {
Collection<String> addresses = adInfo.addresses;
for (String address : addresses) {
try {
if (address == null || !address.startsWith("tcp://")) continue;
int indexOfPort = address.lastIndexOf(':');
if (indexOfPort < 0 || indexOfPort >= address.length() - 2) continue;
String addressPart = address.substring(6, indexOfPort);
String portStr = address.substring(indexOfPort + 1);
int port = Integer.parseInt(portStr);
NodeAddress nodeAddress = NodeAddress.create(addressPart, port);
return nodeAddress;
} catch (Exception exc) {
_logger.info("'{}' node resolved to a bad address - '{}'; ignoring.", node, address);
return null;
}
}
}
return null;
}
@Override
public void registerService(SimpleName node) {
synchronized (_serverLock) {
if (_services.containsKey(node))
throw new IllegalStateException(node + " is already being advertised.");
ServiceItem si = new ServiceItem(node);
_services.put(node, si);
}
} // (method)
/** Used to monitor address changes on the the interface. */
private void handleInterfaceCheck() {
try {
int port = super.getAdvertisementPort();
if (port < 0) {
// can't compose a nodel address yet
_logger.info("(nodel server port still not available; will wait.)");
return;
}
InetAddress localIPv4Address = getLocalIPv4Address();
String nodelAddress = "tcp://" + localIPv4Address.getHostAddress() + ":" + port;
if (nodelAddress.equals(_nodelAddress))
// nothing to do
return;
// the address has changed so should update advertisements
_logger.info(
"An address change has been detected. previous={}, current={}",
_nodelAddress,
nodelAddress);
_nodelAddress = "tcp://" + localIPv4Address.getHostAddress() + ":" + port;
_httpAddress =
"http://"
+ localIPv4Address.getHostAddress()
+ ":"
+ Nodel.getHTTPPort()
+ Nodel.getHTTPSuffix();
Nodel.updateHTTPAddress(_httpAddress);
synchronized (_lock) {
// recycle receiver which will in turn recycle sender
_recycleReceiver = true;
// "signal" thread
Stream.safeClose(_receiveSocket);
}
} catch (Exception exc) {
_logger.warn("'handleInterfaceCheck' did not complete cleanly; ignoring for now.", exc);
}
} // (method)
@Override
public void unregisterService(SimpleName node) {
synchronized (_serverLock) {
if (!_services.containsKey(node))
throw new IllegalStateException(node + " is not advertised anyway.");
_services.remove(node);
}
}
@Override
public Collection<AdvertisementInfo> list() {
long now = System.nanoTime();
_lastList.set(now);
// check how long it has been since the last probe (millis)
long timeSinceProbe = (now - _lastProbe.get()) / 1000000L;
if (timeSinceProbe > LIST_ACTIVITY_PERIOD) sendProbe();
// create snap-shot
List<AdvertisementInfo> ads = new ArrayList<AdvertisementInfo>(_advertisements.size());
synchronized (_clientLock) {
ads.addAll(_advertisements.values());
}
return ads;
}
@Override
public AdvertisementInfo resolve(SimpleName node) {
// indicate client resolution is being used
_usingResolution = true;
return _advertisements.get(node);
}
/** Permanently shuts down all related resources. */
@Override
public void close() throws IOException {
// clear flag
_enabled = false;
// release timers
for (TimerTask timer : _timers) timer.cancel();
Stream.safeClose(_sendSocket, _receiveSocket, _hardLinksSocket);
}
/** Creates or returns the shared instance. */
public static AutoDNS create() {
return Instance.INSTANCE;
}
/** (singleton, thread-safe, non-blocking) */
private static class Instance {
private static final NodelAutoDNS INSTANCE = new NodelAutoDNS();
}
/** Returns the singleton instance of this class. */
public static NodelAutoDNS instance() {
return Instance.INSTANCE;
}
/** Returns the first "sensible" IPv4 address. */
public static InetAddress getLocalIPv4Address() {
InetAddress selectedInterface = s_interface;
// if an interface is being used and IP addresses don't necessarily match, use this candidate
// anyway
InetAddress candidate = null;
try {
Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();
if (en == null) return s_dummyInetAddress;
while (en.hasMoreElements()) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses();
enumIpAddr.hasMoreElements(); ) {
InetAddress inetAddress = enumIpAddr.nextElement();
if (!inetAddress.isLoopbackAddress() && inetAddress instanceof Inet4Address) {
// is an IPv4 address that is not a loopback address
// if interface binding isn't being used, return the found address
if (selectedInterface == null) {
return inetAddress;
} else {
// make first one candidate
if (candidate != null) candidate = inetAddress;
if (selectedInterface.equals(inetAddress)) return inetAddress;
// otherwise keep iterating, will return the candidate at the end
}
}
}
}
} catch (IOException exc) {
// ignore
}
if (candidate != null) return candidate;
return s_dummyInetAddress;
}
/**
* Parses a dotted numerical IP address without throwing any exceptions. (convenience function)
*/
private static InetAddress parseNumericalIPAddress(String dottedNumerical) {
try {
return InetAddress.getByName(dottedNumerical);
} catch (Exception exc) {
throw new Error("Failed to resolve dotted numerical address - " + dottedNumerical);
}
}
/**
* Safely returns true if a packet has the same address and a socket. Used to determine its own
* socket.
*/
private static boolean isSameSocketAddress(DatagramSocket socket, InetSocketAddress addr) {
if (socket == null || addr == null) return false;
SocketAddress socketAddr = socket.getLocalSocketAddress();
return socketAddr != null && socketAddr.equals(addr);
}
/**
* Turns the list of addresses into "resolved" InetSocketAddresses. (should only be called once)
*/
private List<InetSocketAddress> composeHardLinksSocketAddresses() {
List<InetAddress> addresses = Nodel.getHardLinksAddresses();
if (addresses.size() <= 0) return null;
List<InetSocketAddress> socketAddresses = new ArrayList<InetSocketAddress>();
for (InetAddress address : addresses)
socketAddresses.add(new InetSocketAddress(address, MDNS_PORT));
// at least one address is enabled, so initialise a general purpose UDP socket and
// receiver thread.
Thread thread =
new Thread(
new Runnable() {
@Override
public void run() {
hardLinksReceiverThreadMain();
}
},
s_hardLinksSocketlabel);
thread.setDaemon(true);
thread.start();
return socketAddresses;
}
/** (thread entry-point) */
private void hardLinksReceiverThreadMain() {
_logger.info("Instructed to use hardlinks. address:{}", _hardLinksAddresses);
DatagramSocket socket = null;
try {
// initialise a UDP socket on an arbitrary port
_hardLinksSocket = new DatagramSocket();
socket = _hardLinksSocket;
while (_enabled) {
DatagramPacket dp = UDPPacketRecycleQueue.instance().getReadyToUsePacket();
// ('returnPacket' will be called in 'catch' or later after use in thread-pool)
try {
socket.receive(dp);
s_unicastInData.addAndGet(dp.getLength());
s_unicastInOps.incrementAndGet();
enqueueForProcessing(dp, s_hardLinksSocketlabel);
} catch (Exception exc) {
UDPPacketRecycleQueue.instance().returnPacket(dp);
// ignore
}
} // (while)
} catch (Exception exc) {
_logger.warn("Failed to initialise [" + s_hardLinksSocketlabel + "] socket.", exc);
} finally {
_logger.info("[" + s_hardLinksSocketlabel + "] thread run to completion.");
// close for good measure
Stream.safeClose(socket);
}
}
} // (class)
