package org.jgroups.protocols;
import org.jgroups.*;
import org.jgroups.annotations.LocalAddress;
import org.jgroups.annotations.MBean;
import org.jgroups.annotations.Property;
import org.jgroups.conf.PropertyConverters;
import org.jgroups.stack.IpAddress;
import org.jgroups.stack.Protocol;
import org.jgroups.util.Util;
import java.io.*;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.*;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;
/**
* Catches SUSPECT events traveling up the stack. Verifies that the suspected member is really dead. If yes,
* passes SUSPECT event up the stack, otherwise discards it. Has to be placed somewhere above the FD layer and
* below the GMS layer (receiver of the SUSPECT event). Note that SUSPECT events may be reordered by this protocol.
* @author Bela Ban
*/
@MBean(description="Double-checks suspicions reports")
public class VERIFY_SUSPECT extends Protocol implements Runnable {
/* ------------------------------------------ Properties ------------------------------------------ */
@Property(description="Number of millisecs to wait for a response from a suspected member")
private long timeout=2000;
@Property(description="Number of verify heartbeats sent to a suspected member")
private int num_msgs=1;
@Property(description="Use InetAddress.isReachable() to verify suspected member instead of regular messages")
private boolean use_icmp=false;
@LocalAddress
@Property(description="Interface for ICMP pings. Used if use_icmp is true " +
"The following special values are also recognized: GLOBAL, SITE_LOCAL, LINK_LOCAL and NON_LOOPBACK",
systemProperty={Global.BIND_ADDR})
private InetAddress bind_addr; // interface for ICMP pings
@Property(name="bind_interface", converter=PropertyConverters.BindInterface.class,
description="The interface (NIC) which should be used by this transport", dependsUpon="bind_addr")
protected String bind_interface_str=null;
/* --------------------------------------------- Fields ------------------------------------------------ */
/** network interface to be used to send the ICMP packets */
protected NetworkInterface intf=null;
protected Address local_addr=null;
// a list of suspects, ordered by time when a SUSPECT event needs to be sent up
protected final DelayQueue<Entry> suspects=new DelayQueue<Entry>();
protected Thread timer=null;
public VERIFY_SUSPECT() {
}
public Object down(Event evt) {
switch(evt.getType()) {
case Event.SET_LOCAL_ADDRESS:
local_addr=(Address)evt.getArg();
break;
case Event.VIEW_CHANGE:
View v=(View)evt.getArg();
adjustSuspectedMembers(v.getMembers());
break;
}
return down_prot.down(evt);
}
public Object up(Event evt) {
switch(evt.getType()) {
case Event.SUSPECT: // it all starts here ...
Address suspected_mbr=(Address)evt.getArg();
if(suspected_mbr == null) {
if(log.isErrorEnabled()) log.error("suspected member is null");
return null;
}
if(local_addr != null && local_addr.equals(suspected_mbr)) {
if(log.isTraceEnabled())
log.trace("I was suspected; ignoring SUSPECT message");
return null;
}
if(!use_icmp)
verifySuspect(suspected_mbr);
else
verifySuspectWithICMP(suspected_mbr);
return null; // don't pass up; we will decide later (after verification) whether to pass it up
case Event.MSG:
Message msg=(Message)evt.getArg();
VerifyHeader hdr=(VerifyHeader)msg.getHeader(this.id);
if(hdr == null)
break;
switch(hdr.type) {
case VerifyHeader.ARE_YOU_DEAD:
if(hdr.from == null) {
if(log.isErrorEnabled()) log.error("ARE_YOU_DEAD: hdr.from is null");
}
else {
Message rsp;
for(int i=0; i < num_msgs; i++) {
rsp=new Message(hdr.from, null, null);
rsp.setFlag(Message.OOB);
rsp.putHeader(this.id, new VerifyHeader(VerifyHeader.I_AM_NOT_DEAD, local_addr));
down_prot.down(new Event(Event.MSG, rsp));
}
}
return null;
case VerifyHeader.I_AM_NOT_DEAD:
if(hdr.from == null) {
if(log.isErrorEnabled()) log.error("I_AM_NOT_DEAD: hdr.from is null");
return null;
}
unsuspect(hdr.from);
return null;
}
return null;
case Event.CONFIG:
if(bind_addr == null) {
Map<String,Object> config=(Map<String,Object>)evt.getArg();
bind_addr=(InetAddress)config.get("bind_addr");
}
}
return up_prot.up(evt);
}
/**
* Removes all elements from suspects that are <em>not</em> in the new membership
*/
protected void adjustSuspectedMembers(List<Address> new_mbrship) {
synchronized(suspects) {
for(Iterator<Entry> it=suspects.iterator(); it.hasNext();) {
Entry entry=it.next();
if(!new_mbrship.contains(entry.suspect))
it.remove();
}
}
}
/**
* Started when a suspected member is added to suspects. Iterates over the queue as long as there are suspects in
* it and removes a suspect when the timeout for it has elapsed. Sends up a SUSPECT event for every removed suspect.
* When a suspected member is un-suspected, the member is removed from the queue.
*/
public void run() {
while(!suspects.isEmpty() && timer != null) {
try {
Entry entry=suspects.poll(timeout * 2,TimeUnit.MILLISECONDS);
if(entry != null) {
if(log.isTraceEnabled())
log.trace(entry.suspect + " is dead (passing up SUSPECT event)");
up_prot.up(new Event(Event.SUSPECT, entry.suspect));
}
}
catch(InterruptedException e) {
}
}
}
/* --------------------------------- Private Methods ----------------------------------- */
/**
* Sends ARE_YOU_DEAD message to suspected_mbr, wait for return or timeout
*/
void verifySuspect(Address mbr) {
Message msg;
if(mbr == null) return;
addSuspect(mbr);
startTimer(); // start timer before we send out are you dead messages
// moved out of synchronized statement (bela): http://jira.jboss.com/jira/browse/JGRP-302
if(log.isTraceEnabled()) log.trace("verifying that " + mbr + " is dead");
for(int i=0; i < num_msgs; i++) {
msg=new Message(mbr, null, null);
msg.setFlag(Message.OOB);
msg.putHeader(this.id, new VerifyHeader(VerifyHeader.ARE_YOU_DEAD, local_addr));
down_prot.down(new Event(Event.MSG, msg));
}
}
void verifySuspectWithICMP(Address suspected_mbr) {
InetAddress host=suspected_mbr instanceof IpAddress? ((IpAddress)suspected_mbr).getIpAddress() : null;
if(host == null)
throw new IllegalArgumentException("suspected_mbr is not of type IpAddress - FD_ICMP only works with these");
try {
if(log.isTraceEnabled())
log.trace("pinging host " + suspected_mbr + " using interface " + intf);
long start=System.currentTimeMillis(), stop;
boolean rc=host.isReachable(intf, 0, (int)timeout);
stop=System.currentTimeMillis();
if(rc) { // success
if(log.isTraceEnabled())
log.trace("successfully received response from " + host + " (after " + (stop-start) + "ms)");
}
else { // failure
if(log.isTraceEnabled())
log.debug("could not ping " + suspected_mbr + " after " + (stop-start) + "ms; " +
"passing up SUSPECT event");
removeSuspect(suspected_mbr);
up_prot.up(new Event(Event.SUSPECT, suspected_mbr));
}
}
catch(Exception ex) {
if(log.isErrorEnabled())
log.error("failed pinging " + suspected_mbr, ex);
}
}
protected boolean addSuspect(Address suspect) {
if(suspect == null)
return false;
synchronized(suspects) {
for(Entry entry: suspects) // check for duplicates
if(entry.suspect.equals(suspect))
return false;
suspects.add(new Entry(suspect, System.currentTimeMillis() + timeout));
return true;
}
}
protected boolean removeSuspect(Address suspect) {
if(suspect == null)
return false;
boolean retval=false;
synchronized(suspects) {
for(Iterator<Entry> it=suspects.iterator(); it.hasNext();) {
Entry entry=it.next();
if(entry.suspect.equals(suspect)) {
it.remove();
retval=true; // don't break, possibly remove more (2nd line of defense)
}
}
}
return retval;
}
public void unsuspect(Address mbr) {
boolean removed=mbr != null && removeSuspect(mbr);
if(removed) {
if(log.isTraceEnabled()) log.trace("member " + mbr + " was unsuspected");
down_prot.down(new Event(Event.UNSUSPECT, mbr));
up_prot.up(new Event(Event.UNSUSPECT, mbr));
}
}
private synchronized void startTimer() {
if(timer == null || !timer.isAlive()) {
timer=getThreadFactory().newThread(this,"VERIFY_SUSPECT.TimerThread");
timer.setDaemon(true);
timer.start();
}
}
public void init() throws Exception {
super.init();
if(bind_addr != null)
intf=NetworkInterface.getByInetAddress(bind_addr);
}
public synchronized void stop() {
Thread tmp;
if(timer != null && timer.isAlive()) {
tmp=timer;
timer=null;
tmp.interrupt();
tmp=null;
}
timer=null;
}
/* ----------------------------- End of Private Methods -------------------------------- */
protected class Entry implements Delayed {
protected final Address suspect;
protected final long target_time;
public Entry(Address suspect, long target_time) {
this.suspect=suspect;
this.target_time=target_time;
}
public int compareTo(Delayed o) {
Entry other=(Entry)o;
long my_delay=getDelay(TimeUnit.MILLISECONDS), other_delay=other.getDelay(TimeUnit.MILLISECONDS);
return my_delay < other_delay ? -1 : my_delay > other_delay? 1 : 0;
}
public long getDelay(TimeUnit unit) {
long delay=target_time - System.currentTimeMillis();
return unit.convert(delay, TimeUnit.MILLISECONDS);
}
public String toString() {
return suspect + ": " + target_time;
}
}
public static class VerifyHeader extends Header {
static final short ARE_YOU_DEAD=1; // 'from' is sender of verify msg
static final short I_AM_NOT_DEAD=2; // 'from' is suspected member
short type=ARE_YOU_DEAD;
Address from=null; // member who wants to verify that suspected_mbr is dead
public VerifyHeader() {
} // used for externalization
VerifyHeader(short type) {
this.type=type;
}
VerifyHeader(short type, Address from) {
this(type);
this.from=from;
}
public String toString() {
switch(type) {
case ARE_YOU_DEAD:
return "[VERIFY_SUSPECT: ARE_YOU_DEAD]";
case I_AM_NOT_DEAD:
return "[VERIFY_SUSPECT: I_AM_NOT_DEAD]";
default:
return "[VERIFY_SUSPECT: unknown type (" + type + ")]";
}
}
public void writeTo(DataOutput out) throws Exception {
out.writeShort(type);
Util.writeAddress(from, out);
}
public void readFrom(DataInput in) throws Exception {
type=in.readShort();
from=Util.readAddress(in);
}
public int size() {
return Global.SHORT_SIZE + Util.size(from);
}
}
}