[jboss-jira] [JBoss JIRA] Commented: (JGRP-357) Unicast messages to unused port result in infinitely retransmission of message
Vincent Hartsteen (JIRA)
jira-events at lists.jboss.org
Mon Mar 12 05:47:51 EDT 2007
[ http://jira.jboss.com/jira/browse/JGRP-357?page=comments#action_12355789 ]
Vincent Hartsteen commented on JGRP-357:
----------------------------------------
Our app caches the addresses every time it receives a view-change from JGroups. Every now and then we need to send a unicast message and search our destination in our cache of members. When this happens on the moment the destination has left the group and/or re-joined on another port before we have received the view-change we end up in a situation that we are sending to a destination that is not there anymore. This is a race-condition that can always occur no matter how tight the timervalues are set that check the group membership.
The testapplication I've sent merely demonstrates this behavior by sending messages to a random port. This is of course malicious code but it demonstrates the problem. Our real app is a bit less malicious I hope ;-)
I presume this fix is in the service-pack. Depending on our delivery schedule we'll try to use the SP and delete our temporary work-around.
Thanks for resolving this issue.
> Unicast messages to unused port result in infinitely retransmission of message
> ------------------------------------------------------------------------------
>
> Key: JGRP-357
> URL: http://jira.jboss.com/jira/browse/JGRP-357
> Project: JGroups
> Issue Type: Bug
> Affects Versions: 2.4
> Reporter: Vincent Hartsteen
> Assigned To: Bela Ban
> Fix For: 2.5
>
>
> In JGroups 2.4 (but probably this also happens in previous versions, did not verify this) we noticed that it is possible to send a message to a host:port that is not part of the group. This member might have been a member of the group but does not need to have been. This results in the retransmission of the message. However this retransmission never seems to end. The attached program demonstrates this.
> Use the properties file to assign a host-address and port the program will send messages to.
> Properties file:
> ===========
> flood.target.address : 10.220.242.33
> flood.target.port : 2715
> flood.topic : flood.the.network
> flood.stack : UDP(mcast_addr=228.1.2.123;mcast_port=19302;ip_ttl=32;loopback=false;\
> mcast_recv_buf_size=1000000;max_bundle_size=64000;max_bundle_timeout=100;use_incoming_packet_handler=false;\
> use_outgoing_packet_handler=true;ucast_send_buf_size=1000000;ip_ttl=32;enable_bundling=true/):\
> PING(timeout=6000;num_initial_members=8;down_thread=false):\
> MERGE2(max_interval=300000;min_interval=60000;down_thread=false):\
> FD(timeout=30000;max_tries=5;shun=true):\
> pbcast.NAKACK(gc_lag=300;retransmit_timeout=3000,30000,60000,180000;use_mcast_xmit=false;max_xmit_size=8192):\
> UNICAST(timeout=3000,30000,60000,180000):\
> pbcast.STABLE(desired_avg_gossip=300000;stability_delay=30000;max_bytes=65536;down_thread=false):\
> pbcast.GMS(join_timeout=10000;join_retry_timeout=5000;shun=true;print_local_addr=true;down_thread=false):\
> FC(max_credits=64000;min_credits=8000;down_thread=false):\
> FRAG2(frag_size=8000;down_thread=false;up_thread=false):\
> COMPRESS(down_thread=false;min_size=256;compression_level=9;up_thread=true):\
> pbcast.STATE_TRANSFER(down_thread=false;up_thread=false)
> Program:
> =======
> public class Flooder implements MembershipListener, RequestHandler, RspCollector {
> private static Log log = LogFactory.getLog(Flooder.class);
> private static int counter = 0;
> private Channel channel = null;
> private MessageDispatcher dispatcher = null;
> private Timer floodTimer = null;
> private InetAddress targetAddr;
> private int targetPort;
> private String topic;
> private String stack;
> public Flooder() throws IOException, ChannelException {
> Properties properties = new Properties();
> InputStream in = ClassLoader.getSystemClassLoader().getResourceAsStream("flooder.properties");
> properties.load(in);
> in.close();
>
> targetAddr = InetAddress.getByName(properties.getProperty("flood.target.address").trim());
> targetPort = Integer.parseInt(properties.getProperty("flood.target.port"));
> topic = properties.getProperty("flood.topic");
> stack = properties.getProperty("flood.stack");
> initialize();
> }
> public void initialize() throws ChannelException {
> channel = new JChannel(stack);
> channel.setOpt(Channel.BLOCK, Boolean.TRUE);
> channel.setOpt(Channel.GET_STATE_EVENTS, Boolean.TRUE);
> channel.setOpt(Channel.AUTO_RECONNECT, Boolean.TRUE);
> channel.setOpt(Channel.AUTO_GETSTATE, Boolean.TRUE);
> channel.connect(topic);
> dispatcher = new MessageDispatcher(channel, null, this, this);
> log.trace("Connected to topic " + topic + " w/ stack: " + ((JChannel)channel).getProtocolStack().printProtocolSpec(true));
> }
> public void startFlooding() {
> if (floodTimer != null) floodTimer.cancel();
> floodTimer = new Timer();
> floodTimer.schedule(new TimerTask() {
> @Override
> public void run() {
> Address address = new IpAddress(targetAddr, targetPort);
> Message msg = new Message(address, null, ("Flooooooooood#" + ++counter + "#").getBytes());
> Vector<Address> victor = new Vector<Address>(1);
> victor.add(address);
> dispatcher.castMessage(victor, System.currentTimeMillis(), msg, Flooder.this);
> log.trace("Sent Flooding message #" + counter + " to " + address + " @ " + new Date());
> }
> }, 1000, 10000);
> }
> public void block() {
> log.trace("BLOCK");
> }
> public void suspect(Address addr) {
> log.trace("SUSPECT: " + addr);
> }
> public void viewAccepted(View v) {
> log.trace("VIEW ACCEPTED: " + v);
> }
> public Object handle(Message msg) {
> log.trace("MESSAGE RECEIVED: " + msg);
> return "HANDLED";
> }
> public void receiveResponse(Message m) {
> log.trace("RECEIVE RESPONSE: " + m + " hdr=" + m.getHeaders());
> }
> public void viewChange(View v) {
> log.trace("VIEW CHANGE: " + v);
> }
>
> public static void main(String[] args) {
> try {
> Flooder flooder = new Flooder();
> flooder.startFlooding();
> } catch (Exception ex) {
> log.error("Exception occurred: ", ex);
> }
> }
> }
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