package org.jgroups.protocols;
import org.jgroups.*;
import org.jgroups.annotations.MBean;
import org.jgroups.annotations.ManagedAttribute;
import org.jgroups.annotations.ManagedOperation;
import org.jgroups.annotations.Property;
import org.jgroups.conf.PropertyConverters;
import org.jgroups.stack.Protocol;
import org.jgroups.util.AgeOutCache;
import org.jgroups.util.Table;
import org.jgroups.util.TimeScheduler;
import org.jgroups.util.Util;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.*;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* Reliable unicast layer. Uses acknowledgement scheme similar to TCP to provide lossless transmission
* of unicast messages (for reliable multicast see NAKACK layer). When a message is sent to a peer for
* the first time, we add the pair <peer_addr, Entry> to the hashtable (peer address is the key). All
* messages sent to that peer will be added to hashtable.peer_addr.sent_msgs. When we receive a
* message from a peer for the first time, another entry will be created and added to the hashtable
* (unless already existing). Msgs will then be added to hashtable.peer_addr.received_msgs.<p> This
* layer is used to reliably transmit point-to-point messages, that is, either messages sent to a
* single receiver (vs. messages multicast to a group) or for example replies to a multicast message. The
* sender uses an <code>AckSenderWindow</code> which retransmits messages for which it hasn't received
* an ACK, the receiver uses <code>AckReceiverWindow</code> which keeps track of the lowest seqno
* received so far, and keeps messages in order.<p>
* Messages in both AckSenderWindows and AckReceiverWindows will be removed. A message will be removed from
* AckSenderWindow when an ACK has been received for it and messages will be removed from AckReceiverWindow
* whenever a message is received: the new message is added and then we try to remove as many messages as
* possible (until we stop at a gap, or there are no more messages).
* @author Bela Ban
*/
@MBean(description="Reliable unicast layer")
public class UNICAST extends Protocol implements AgeOutCache.Handler<Address> {
public static final long DEFAULT_FIRST_SEQNO=Global.DEFAULT_FIRST_UNICAST_SEQNO;
/* ------------------------------------------ Properties ------------------------------------------ */
@Deprecated
protected int[] timeout= { 400, 800, 1600, 3200 }; // for AckSenderWindow: max time to wait for missing acks
@Property(description="Max number of messages to be removed from a retransmit window. This property might " +
"get removed anytime, so don't use it !")
protected int max_msg_batch_size=500;
@Property(description="Time (in milliseconds) after which an idle incoming or outgoing connection is closed. The " +
"connection will get re-established when used again. 0 disables connection reaping")
protected long conn_expiry_timeout=60000;
@Deprecated
@Property(description="Size (in bytes) of a Segment in the segments table. Only for experts, do not use !",
deprecatedMessage="not used anymore")
protected int segment_capacity=1000;
@Property(description="Number of rows of the matrix in the retransmission table (only for experts)",writable=false)
protected int xmit_table_num_rows=100;
@Property(description="Number of elements of a row of the matrix in the retransmission table (only for experts). " +
"The capacity of the matrix is xmit_table_num_rows * xmit_table_msgs_per_row",writable=false)
protected int xmit_table_msgs_per_row=1000;
@Property(description="Resize factor of the matrix in the retransmission table (only for experts)",writable=false)
protected double xmit_table_resize_factor=1.2;
@Property(description="Number of milliseconds after which the matrix in the retransmission table " +
"is compacted (only for experts)",writable=false)
protected long xmit_table_max_compaction_time=10 * 60 * 1000;
@Property(description="Interval (in milliseconds) at which messages in the send windows are resent")
protected long xmit_interval=2000;
/* --------------------------------------------- JMX ---------------------------------------------- */
protected long num_msgs_sent=0, num_msgs_received=0;
protected long num_acks_sent=0, num_acks_received=0, num_xmits=0;
/* --------------------------------------------- Fields ------------------------------------------------ */
protected final ConcurrentMap<Address, SenderEntry> send_table=Util.createConcurrentMap();
protected final ConcurrentMap<Address, ReceiverEntry> recv_table=Util.createConcurrentMap();
protected final ReentrantLock recv_table_lock=new ReentrantLock();
/** RetransmitTask running every xmit_interval ms */
protected Future<?> xmit_task;
protected volatile List<Address> members=new ArrayList<Address>(11);
protected Address local_addr=null;
protected TimeScheduler timer=null; // used for retransmissions (passed to AckSenderWindow)
protected volatile boolean running=false;
protected short last_conn_id=0;
protected long max_retransmit_time=60 * 1000L;
protected AgeOutCache<Address> cache=null;
protected Future<?> connection_reaper; // closes idle connections
public int[] getTimeout() {return timeout;}
@Deprecated
@Property(name="timeout",converter=PropertyConverters.IntegerArray.class, deprecatedMessage="not used anymore")
public void setTimeout(int[] val) {
if(val != null)
timeout=val;
}
public void setMaxMessageBatchSize(int size) {
if(size >= 1)
max_msg_batch_size=size;
}
@ManagedAttribute
public String getLocalAddress() {return local_addr != null? local_addr.toString() : "null";}
@ManagedAttribute
public String getMembers() {return members.toString();}
@ManagedAttribute(description="Whether the ConnectionReaper task is running")
public boolean isConnectionReaperRunning() {return connection_reaper != null && !connection_reaper.isDone();}
@ManagedAttribute(description="Returns the number of outgoing (send) connections")
public int getNumSendConnections() {
return send_table.size();
}
@ManagedAttribute(description="Returns the number of incoming (receive) connections")
public int getNumReceiveConnections() {
return recv_table.size();
}
@ManagedAttribute(description="Returns the total number of outgoing (send) and incoming (receive) connections")
public int getNumConnections() {
return getNumReceiveConnections() + getNumSendConnections();
}
@ManagedOperation
public String printConnections() {
StringBuilder sb=new StringBuilder();
if(!send_table.isEmpty()) {
sb.append("\nsend connections:\n");
for(Map.Entry<Address,SenderEntry> entry: send_table.entrySet()) {
sb.append(entry.getKey()).append(": ").append(entry.getValue()).append("\n");
}
}
if(!recv_table.isEmpty()) {
sb.append("\nreceive connections:\n");
for(Map.Entry<Address,ReceiverEntry> entry: recv_table.entrySet()) {
sb.append(entry.getKey()).append(": ").append(entry.getValue()).append("\n");
}
}
return sb.toString();
}
@ManagedAttribute
public long getNumMessagesSent() {return num_msgs_sent;}
@ManagedAttribute
public long getNumMessagesReceived() {return num_msgs_received;}
@ManagedAttribute
public long getNumAcksSent() {return num_acks_sent;}
@ManagedAttribute
public long getNumAcksReceived() {return num_acks_received;}
@ManagedAttribute
public long getNumXmits() {return num_xmits;}
public long getMaxRetransmitTime() {return max_retransmit_time;}
@Property(description="Max number of milliseconds we try to retransmit a message to any given member. After that, " +
"the connection is removed. Any new connection to that member will start with seqno #1 again. 0 disables this")
public void setMaxRetransmitTime(long max_retransmit_time) {
this.max_retransmit_time=max_retransmit_time;
if(cache != null && max_retransmit_time > 0)
cache.setTimeout(max_retransmit_time);
}
@ManagedAttribute(description="Is the retransmit task running")
public boolean isXmitTaskRunning() {return xmit_task != null && !xmit_task.isDone();}
@ManagedAttribute
public int getAgeOutCacheSize() {
return cache != null? cache.size() : 0;
}
@ManagedOperation
public String printAgeOutCache() {
return cache != null? cache.toString() : "n/a";
}
public AgeOutCache<Address> getAgeOutCache() {
return cache;
}
/** The number of messages in all Entry.sent_msgs tables (haven't received an ACK yet) */
@ManagedAttribute
public int getNumUnackedMessages() {
int num=0;
for(SenderEntry entry: send_table.values()) {
if(entry.sent_msgs != null)
num+=entry.sent_msgs.size();
}
return num;
}
@ManagedAttribute
public int getNumberOfMessagesInReceiveWindows() {
int num=0;
for(ReceiverEntry entry: recv_table.values()) {
if(entry.received_msgs != null)
num+=entry.received_msgs.size();
}
return num;
}
@ManagedAttribute(description="Total number of undelivered messages in all receive windows")
public long getXmitTableUndeliveredMessages() {
long retval=0;
for(ReceiverEntry entry: recv_table.values()) {
if(entry.received_msgs != null)
retval+=entry.received_msgs.size();
}
return retval;
}
@ManagedAttribute(description="Total number of missing messages in all receive windows")
public long getXmitTableMissingMessages() {
long retval=0;
for(ReceiverEntry entry: recv_table.values()) {
if(entry.received_msgs != null)
retval+=entry.received_msgs.getNumMissing();
}
return retval;
}
@ManagedAttribute(description="Number of compactions in all (receive and send) windows")
public int getXmitTableNumCompactions() {
int retval=0;
for(ReceiverEntry entry: recv_table.values()) {
if(entry.received_msgs != null)
retval+=entry.received_msgs.getNumCompactions();
}
for(SenderEntry entry: send_table.values()) {
if(entry.sent_msgs != null)
retval+=entry.sent_msgs.getNumCompactions();
}
return retval;
}
@ManagedAttribute(description="Number of moves in all (receive and send) windows")
public int getXmitTableNumMoves() {
int retval=0;
for(ReceiverEntry entry: recv_table.values()) {
if(entry.received_msgs != null)
retval+=entry.received_msgs.getNumMoves();
}
for(SenderEntry entry: send_table.values()) {
if(entry.sent_msgs != null)
retval+=entry.sent_msgs.getNumMoves();
}
return retval;
}
@ManagedAttribute(description="Number of resizes in all (receive and send) windows")
public int getXmitTableNumResizes() {
int retval=0;
for(ReceiverEntry entry: recv_table.values()) {
if(entry.received_msgs != null)
retval+=entry.received_msgs.getNumResizes();
}
for(SenderEntry entry: send_table.values()) {
if(entry.sent_msgs != null)
retval+=entry.sent_msgs.getNumResizes();
}
return retval;
}
@ManagedAttribute(description="Number of purges in all (receive and send) windows")
public int getXmitTableNumPurges() {
int retval=0;
for(ReceiverEntry entry: recv_table.values()) {
if(entry.received_msgs != null)
retval+=entry.received_msgs.getNumPurges();
}
for(SenderEntry entry: send_table.values()) {
if(entry.sent_msgs != null)
retval+=entry.sent_msgs.getNumPurges();
}
return retval;
}
@ManagedOperation(description="Prints the contents of the receive windows for all members")
public String printReceiveWindowMessages() {
StringBuilder ret=new StringBuilder(local_addr + ":\n");
for(Map.Entry<Address,ReceiverEntry> entry: recv_table.entrySet()) {
Address addr=entry.getKey();
Table<Message> buf=entry.getValue().received_msgs;
ret.append(addr).append(": ").append(buf.toString()).append('\n');
}
return ret.toString();
}
@ManagedOperation(description="Prints the contents of the send windows for all members")
public String printSendWindowMessages() {
StringBuilder ret=new StringBuilder(local_addr + ":\n");
for(Map.Entry<Address,SenderEntry> entry: send_table.entrySet()) {
Address addr=entry.getKey();
Table<Message> buf=entry.getValue().sent_msgs;
ret.append(addr).append(": ").append(buf.toString()).append('\n');
}
return ret.toString();
}
public void resetStats() {
num_msgs_sent=num_msgs_received=num_acks_sent=num_acks_received=0;
num_xmits=0;
}
public Map<String, Object> dumpStats() {
Map<String, Object> m=super.dumpStats();
m.put("num_unacked_msgs", getNumUnackedMessages());
m.put("num_msgs_in_recv_windows", getNumberOfMessagesInReceiveWindows());
return m;
}
public void start() throws Exception {
timer=getTransport().getTimer();
if(timer == null)
throw new Exception("timer is null");
if(max_retransmit_time > 0)
cache=new AgeOutCache<Address>(timer, max_retransmit_time, this);
running=true;
if(conn_expiry_timeout > 0)
startConnectionReaper();
startRetransmitTask();
}
public void stop() {
running=false;
stopRetransmitTask();
stopConnectionReaper();
removeAllConnections();
}
public Object up(Event evt) {
Message msg;
Address dst, src;
UnicastHeader hdr;
switch(evt.getType()) {
case Event.MSG:
msg=(Message)evt.getArg();
dst=msg.getDest();
if(dst == null || msg.isFlagSet(Message.NO_RELIABILITY)) // only handle unicast messages
break; // pass up
// changed from removeHeader(): we cannot remove the header because if we do loopback=true at the
// transport level, we will not have the header on retransmit ! (bela Aug 22 2006)
hdr=(UnicastHeader)msg.getHeader(this.id);
if(hdr == null)
break;
src=msg.getSrc();
switch(hdr.type) {
case UnicastHeader.DATA: // received regular message
handleDataReceived(src, hdr.seqno, hdr.conn_id, hdr.first, msg, evt);
return null; // we pass the deliverable message up in handleDataReceived()
case UnicastHeader.ACK: // received ACK for previously sent message
handleAckReceived(src, hdr.seqno);
break;
case UnicastHeader.SEND_FIRST_SEQNO:
handleResendingOfFirstMessage(src, hdr.seqno);
break;
default:
log.error("UnicastHeader type " + hdr.type + " not known !");
break;
}
return null;
}
return up_prot.up(evt); // Pass up to the layer above us
}
public Object down(Event evt) {
switch (evt.getType()) {
case Event.MSG: // Add UnicastHeader, add to AckSenderWindow and pass down
Message msg=(Message)evt.getArg();
Address dst=msg.getDest();
/* only handle unicast messages */
if (dst == null || msg.isFlagSet(Message.NO_RELIABILITY))
break;
if(!running) {
if(log.isTraceEnabled())
log.trace("discarded message as start() has not yet been called, message: " + msg);
return null;
}
SenderEntry entry=send_table.get(dst);
if(entry == null) {
entry=new SenderEntry(getNewConnectionId());
SenderEntry existing=send_table.putIfAbsent(dst, entry);
if(existing != null)
entry=existing;
else {
if(log.isTraceEnabled())
log.trace(local_addr + ": created connection to " + dst);
if(cache != null && !members.contains(dst))
cache.add(dst);
}
}
short send_conn_id=entry.send_conn_id;
long seqno=entry.sent_msgs_seqno.getAndIncrement();
long sleep=10;
while(running) {
try {
msg.putHeader(this.id, UnicastHeader.createDataHeader(seqno,send_conn_id,seqno == DEFAULT_FIRST_SEQNO));
entry.sent_msgs.add(seqno,msg); // add *including* UnicastHeader, adds to retransmitter
if(conn_expiry_timeout > 0)
entry.update();
break;
}
catch(Throwable t) {
if(!running)
break;
Util.sleep(sleep);
sleep=Math.min(5000, sleep*2);
}
}
if(log.isTraceEnabled()) {
StringBuilder sb=new StringBuilder();
sb.append(local_addr).append(" --> DATA(").append(dst).append(": #").append(seqno).
append(", conn_id=").append(send_conn_id);
if(seqno == DEFAULT_FIRST_SEQNO) sb.append(", first");
sb.append(')');
log.trace(sb);
}
num_msgs_sent++;
return down_prot.down(evt);
case Event.VIEW_CHANGE: // remove connections to peers that are not members anymore !
View view=(View)evt.getArg();
List<Address> new_members=view.getMembers();
Set<Address> non_members=new HashSet<Address>(send_table.keySet());
non_members.addAll(recv_table.keySet());
members=new_members;
non_members.removeAll(new_members);
if(cache != null)
cache.removeAll(new_members);
if(!non_members.isEmpty()) {
if(log.isTraceEnabled())
log.trace("removing non members " + non_members);
for(Address non_mbr: non_members)
removeConnection(non_mbr);
}
break;
case Event.SET_LOCAL_ADDRESS:
local_addr=(Address)evt.getArg();
break;
}
return down_prot.down(evt); // Pass on to the layer below us
}
protected void send(Message msg, Event evt) {
down_prot.down(evt);
num_msgs_sent++;
}
/**
* Removes and resets from connection table (which is already locked). Returns true if member was found,
* otherwise false. This method is public only so it can be invoked by unit testing, but should not otherwise be
* used !
*/
public void removeConnection(Address mbr) {
removeSendConnection(mbr);
removeReceiveConnection(mbr);
}
public void removeSendConnection(Address mbr) {
send_table.remove(mbr);
}
public void removeReceiveConnection(Address mbr) {
recv_table.remove(mbr);
}
/**
* This method is public only so it can be invoked by unit testing, but should not otherwise be used !
*/
@ManagedOperation(description="Trashes all connections to other nodes. This is only used for testing")
public void removeAllConnections() {
send_table.clear();
recv_table.clear();
}
/** Called by AckSenderWindow to resend messages for which no ACK has been received yet */
public void retransmit(Message msg) {
if(log.isTraceEnabled()) {
UnicastHeader hdr=(UnicastHeader)msg.getHeader(id);
long seqno=hdr != null? hdr.seqno : -1;
log.trace(local_addr + " --> XMIT(" + msg.getDest() + ": #" + seqno + ')');
}
down_prot.down(new Event(Event.MSG,msg));
num_xmits++;
}
/**
* Called by AgeOutCache, to removed expired connections
* @param key
*/
public void expired(Address key) {
if(key != null) {
if(log.isDebugEnabled())
log.debug("removing connection to " + key + " because it expired");
removeConnection(key);
}
}
/**
* Check whether the hashtable contains an entry e for <code>sender</code> (create if not). If
* e.received_msgs is null and <code>first</code> is true: create a new AckReceiverWindow(seqno) and
* add message. Set e.received_msgs to the new window. Else just add the message.
*/
protected void handleDataReceived(Address sender, long seqno, short conn_id, boolean first, Message msg, Event evt) {
if(log.isTraceEnabled()) {
StringBuilder sb=new StringBuilder();
sb.append(local_addr).append(" <-- DATA(").append(sender).append(": #").append(seqno);
if(conn_id != 0) sb.append(", conn_id=").append(conn_id);
if(first) sb.append(", first");
sb.append(')');
log.trace(sb);
}
ReceiverEntry entry=getReceiverEntry(sender, seqno, first, conn_id);
if(entry == null)
return;
if(conn_expiry_timeout > 0)
entry.update();
Table<Message> win=entry.received_msgs;
boolean added=win.add(seqno, msg); // win is guaranteed to be non-null if we get here
num_msgs_received++;
// An OOB message is passed up immediately. Later, when remove() is called, we discard it. This affects ordering !
// http://jira.jboss.com/jira/browse/JGRP-377
if(msg.isFlagSet(Message.OOB) && added) {
try {
up_prot.up(evt);
}
catch(Throwable t) {
log.error("couldn't deliver OOB message " + msg, t);
}
}
final AtomicBoolean processing=win.getProcessing();
if(!processing.compareAndSet(false, true)) {
return;
}
// try to remove (from the AckReceiverWindow) as many messages as possible as pass them up
// Prevents concurrent passing up of messages by different threads (http://jira.jboss.com/jira/browse/JGRP-198);
// this is all the more important once we have a concurrent stack (http://jira.jboss.com/jira/browse/JGRP-181),
// where lots of threads can come up to this point concurrently, but only 1 is allowed to pass at a time
// We *can* deliver messages from *different* senders concurrently, e.g. reception of P1, Q1, P2, Q2 can result in
// delivery of P1, Q1, Q2, P2: FIFO (implemented by UNICAST) says messages need to be delivered only in the
// order in which they were sent by their senders
int num_msgs=removeAndDeliver(processing, win);
if(num_msgs > 0) {
long hd=win.getHighestDelivered();
sendAck(sender, hd);
}
}
protected int removeAndDeliver(final AtomicBoolean processing, Table<Message> win) {
int retval=0;
boolean released_processing=false;
try {
while(true) {
List<Message> list=win.removeMany(processing, true, max_msg_batch_size);
if(list == null) {
released_processing=true;
return retval;
}
for(Message m: list) {
retval++;
// discard OOB msg: it has already been delivered (http://jira.jboss.com/jira/browse/JGRP-377)
if(m.isFlagSet(Message.OOB))
continue;
try {
up_prot.up(new Event(Event.MSG, m));
}
catch(Throwable t) {
log.error("couldn't deliver message " + m, t);
}
}
}
}
finally {
// processing is always set in win.remove(processing) above and never here ! This code is just a
// 2nd line of defense should there be an exception before win.remove(processing) sets processing
if(!released_processing)
processing.set(false);
}
}
protected ReceiverEntry getReceiverEntry(Address sender, long seqno, boolean first, short conn_id) {
ReceiverEntry entry=recv_table.get(sender);
if(entry != null && entry.recv_conn_id == conn_id)
return entry;
recv_table_lock.lock();
try {
entry=recv_table.get(sender);
if(first) {
if(entry == null) {
entry=getOrCreateReceiverEntry(sender, seqno, conn_id);
}
else { // entry != null && win != null
if(conn_id != entry.recv_conn_id) {
if(log.isTraceEnabled())
log.trace(local_addr + ": conn_id=" + conn_id + " != " + entry.recv_conn_id + "; resetting receiver window");
recv_table.remove(sender);
entry=getOrCreateReceiverEntry(sender, seqno, conn_id);
}
else {
;
}
}
}
else { // entry == null && win == null OR entry != null && win == null OR entry != null && win != null
if(entry == null || entry.recv_conn_id != conn_id) {
recv_table_lock.unlock();
sendRequestForFirstSeqno(sender, seqno); // drops the message and returns (see below)
return null;
}
}
return entry;
}
finally {
if(recv_table_lock.isHeldByCurrentThread())
recv_table_lock.unlock();
}
}
protected ReceiverEntry getOrCreateReceiverEntry(Address sender, long seqno, short conn_id) {
Table<Message> table=new Table<Message>(xmit_table_num_rows, xmit_table_msgs_per_row, seqno-1,
xmit_table_resize_factor, xmit_table_max_compaction_time);
ReceiverEntry entry=new ReceiverEntry(table, conn_id);
ReceiverEntry entry2=recv_table.putIfAbsent(sender, entry);
if(entry2 != null)
return entry2;
if(log.isTraceEnabled())
log.trace(local_addr + ": created receiver window for " + sender + " at seqno=#" + seqno + " for conn-id=" + conn_id);
return entry;
}
/** Add the ACK to hashtable.sender.sent_msgs */
protected void handleAckReceived(Address sender, long seqno) {
if(log.isTraceEnabled())
log.trace(new StringBuilder().append(local_addr).append(" <-- ACK(").append(sender).
append(": #").append(seqno).append(')'));
SenderEntry entry=send_table.get(sender);
Table<Message> win=entry != null? entry.sent_msgs : null;
if(win != null) {
win.purge(seqno, true); // removes all messages <= seqno (forced purge)
num_acks_received++;
}
}
/**
* We need to resend our first message with our conn_id
* @param sender
* @param seqno Resend the non null messages in the range [lowest .. seqno]
*/
protected void handleResendingOfFirstMessage(Address sender, long seqno) {
if(log.isTraceEnabled())
log.trace(local_addr + " <-- SEND_FIRST_SEQNO(" + sender + "," + seqno + ")");
SenderEntry entry=send_table.get(sender);
Table<Message> win=entry != null? entry.sent_msgs : null;
if(win == null) {
if(log.isWarnEnabled())
log.warn(local_addr + ": sender window for " + sender + " not found");
return;
}
boolean first_sent=false;
for(long i=win.getLow() +1; i <= seqno; i++) {
Message rsp=win.get(i);
if(rsp == null)
continue;
if(first_sent) {
down_prot.down(new Event(Event.MSG, rsp));
}
else {
first_sent=true;
// We need to copy the UnicastHeader and put it back into the message because Message.copy() doesn't copy
// the headers and therefore we'd modify the original message in the sender retransmission window
// (https://jira.jboss.org/jira/browse/JGRP-965)
Message copy=rsp.copy();
UnicastHeader hdr=(UnicastHeader)copy.getHeader(this.id);
UnicastHeader newhdr=hdr.copy();
newhdr.first=true;
copy.putHeader(this.id, newhdr);
down_prot.down(new Event(Event.MSG, copy));
}
}
}
protected void startRetransmitTask() {
if(xmit_task == null || xmit_task.isDone())
xmit_task=timer.scheduleWithFixedDelay(new RetransmitTask(), 0, xmit_interval, TimeUnit.MILLISECONDS);
}
protected void stopRetransmitTask() {
if(xmit_task != null) {
xmit_task.cancel(true);
xmit_task=null;
}
}
protected void sendAck(Address dst, long seqno) {
if(!running) // if we are disconnected, then don't send any acks which throw exceptions on shutdown
return;
Message ack=new Message(dst);
ack.putHeader(this.id, UnicastHeader.createAckHeader(seqno));
if(log.isTraceEnabled())
log.trace(new StringBuilder().append(local_addr).append(" --> ACK(").append(dst).
append(": #").append(seqno).append(')'));
try {
down_prot.down(new Event(Event.MSG, ack));
num_acks_sent++;
}
catch(Throwable t) {
log.error("failed sending ACK(" + seqno + ") to " + dst, t);
}
}
protected synchronized void startConnectionReaper() {
if(connection_reaper == null || connection_reaper.isDone())
connection_reaper=timer.scheduleWithFixedDelay(new ConnectionReaper(), conn_expiry_timeout, conn_expiry_timeout, TimeUnit.MILLISECONDS);
}
protected synchronized void stopConnectionReaper() {
if(connection_reaper != null)
connection_reaper.cancel(false);
}
protected synchronized short getNewConnectionId() {
short retval=last_conn_id;
if(last_conn_id >= Short.MAX_VALUE || last_conn_id < 0)
last_conn_id=0;
else
last_conn_id++;
return retval;
}
protected void sendRequestForFirstSeqno(Address dest, long seqno_received) {
Message msg=new Message(dest);
msg.setFlag(Message.OOB);
UnicastHeader hdr=UnicastHeader.createSendFirstSeqnoHeader(seqno_received);
msg.putHeader(this.id, hdr);
if(log.isTraceEnabled())
log.trace(local_addr + " --> SEND_FIRST_SEQNO(" + dest + "," + seqno_received + ")");
down_prot.down(new Event(Event.MSG, msg));
}
@ManagedOperation(description="Closes connections that have been idle for more than conn_expiry_timeout ms")
public void reapIdleConnections() {
// remove expired connections from send_table
for(Map.Entry<Address,SenderEntry> entry: send_table.entrySet()) {
SenderEntry val=entry.getValue();
long age=val.age();
if(age >= conn_expiry_timeout) {
removeSendConnection(entry.getKey());
if(log.isDebugEnabled())
log.debug(local_addr + ": removed expired connection for " + entry.getKey() +
" (" + age + " ms old) from send_table");
}
}
// remove expired connections from recv_table
for(Map.Entry<Address,ReceiverEntry> entry: recv_table.entrySet()) {
ReceiverEntry val=entry.getValue();
long age=val.age();
if(age >= conn_expiry_timeout) {
removeReceiveConnection(entry.getKey());
if(log.isDebugEnabled())
log.debug(local_addr + ": removed expired connection for " + entry.getKey() +
" (" + age + " ms old) from recv_table");
}
}
}
/**
* The following types and fields are serialized:
* <pre>
* | DATA | seqno | conn_id | first |
* | ACK | seqno |
* | SEND_FIRST_SEQNO |
* </pre>
*/
public static class UnicastHeader extends Header {
public static final byte DATA = 0;
public static final byte ACK = 1;
public static final byte SEND_FIRST_SEQNO = 2;
byte type;
long seqno; // DATA and ACK
short conn_id; // DATA
boolean first; // DATA
public UnicastHeader() {} // used for externalization
public static UnicastHeader createDataHeader(long seqno, short conn_id, boolean first) {
return new UnicastHeader(DATA, seqno, conn_id, first);
}
public static UnicastHeader createAckHeader(long seqno) {
return new UnicastHeader(ACK, seqno);
}
public static UnicastHeader createSendFirstSeqnoHeader(long seqno_received) {
return new UnicastHeader(SEND_FIRST_SEQNO, seqno_received);
}
protected UnicastHeader(byte type, long seqno) {
this.type=type;
this.seqno=seqno;
}
protected UnicastHeader(byte type, long seqno, short conn_id, boolean first) {
this.type=type;
this.seqno=seqno;
this.conn_id=conn_id;
this.first=first;
}
public long getSeqno() {
return seqno;
}
public String toString() {
StringBuilder sb=new StringBuilder();
sb.append(type2Str(type)).append(", seqno=").append(seqno);
if(conn_id != 0) sb.append(", conn_id=").append(conn_id);
if(first) sb.append(", first");
return sb.toString();
}
public static String type2Str(byte t) {
switch(t) {
case DATA: return "DATA";
case ACK: return "ACK";
case SEND_FIRST_SEQNO: return "SEND_FIRST_SEQNO";
default: return "<unknown>";
}
}
public final int size() {
int retval=Global.BYTE_SIZE; // type
switch(type) {
case DATA:
retval+=Util.size(seqno) // seqno
+ Global.SHORT_SIZE // conn_id
+ Global.BYTE_SIZE; // first
break;
case ACK:
retval+=Util.size(seqno); // seqno
break;
case SEND_FIRST_SEQNO:
retval+=Util.size(seqno);
break;
}
return retval;
}
public UnicastHeader copy() {
return new UnicastHeader(type, seqno, conn_id, first);
}
public void writeTo(DataOutput out) throws Exception {
out.writeByte(type);
switch(type) {
case DATA:
Util.writeLong(seqno, out);
out.writeShort(conn_id);
out.writeBoolean(first);
break;
case ACK:
Util.writeLong(seqno, out);
break;
case SEND_FIRST_SEQNO:
Util.writeLong(seqno, out);
break;
}
}
public void readFrom(DataInput in) throws Exception {
type=in.readByte();
switch(type) {
case DATA:
seqno=Util.readLong(in);
conn_id=in.readShort();
first=in.readBoolean();
break;
case ACK:
seqno=Util.readLong(in);
break;
case SEND_FIRST_SEQNO:
seqno=Util.readLong(in);
break;
}
}
}
protected final class SenderEntry {
// stores (and retransmits) msgs sent by us to a certain peer
final Table<Message> sent_msgs;
final AtomicLong sent_msgs_seqno=new AtomicLong(DEFAULT_FIRST_SEQNO); // seqno for msgs sent by us
final short send_conn_id;
protected final AtomicLong timestamp=new AtomicLong(0);
final Lock lock=new ReentrantLock();
public SenderEntry(short send_conn_id) {
this.send_conn_id=send_conn_id;
this.sent_msgs=new Table<Message>(xmit_table_num_rows, xmit_table_msgs_per_row, 0,
xmit_table_resize_factor, xmit_table_max_compaction_time);
update();
}
void update() {timestamp.set(System.currentTimeMillis());}
long age() {return System.currentTimeMillis() - timestamp.longValue();}
public String toString() {
StringBuilder sb=new StringBuilder();
if(sent_msgs != null)
sb.append(sent_msgs).append(", ");
sb.append("send_conn_id=" + send_conn_id).append(" (" + age() + " ms old)");
return sb.toString();
}
}
protected static final class ReceiverEntry {
protected final Table<Message> received_msgs; // stores all msgs rcvd by a certain peer in seqno-order
protected final long recv_conn_id;
protected final AtomicLong timestamp=new AtomicLong(0);
public ReceiverEntry(Table<Message> received_msgs, long recv_conn_id) {
this.received_msgs=received_msgs;
this.recv_conn_id=recv_conn_id;
update();
}
void update() {timestamp.set(System.currentTimeMillis());}
long age() {return System.currentTimeMillis() - timestamp.longValue();}
public String toString() {
StringBuilder sb=new StringBuilder();
if(received_msgs != null)
sb.append(received_msgs).append(", ");
sb.append("recv_conn_id=" + recv_conn_id);
sb.append(" (" + age() + " ms old)");
return sb.toString();
}
}
protected class ConnectionReaper implements Runnable {
public void run() {
reapIdleConnections();
}
}
/**
* Retransmitter task which periodically (every xmit_interval ms) looks at all the retransmit (send) tables and
* re-sends messages for which we haven't received an ack yet
*/
protected class RetransmitTask implements Runnable {
public void run() {
for(SenderEntry val: send_table.values()) {
Table<Message> buf=val != null? val.sent_msgs : null;
if(buf != null && !buf.isEmpty()) {
long from=buf.getHighestDelivered()+1, to=buf.getHighestReceived();
List<Message> list=buf.get(from, to);
if(list != null) {
for(Message msg: list)
retransmit(msg);
}
}
}
}
}
}