package org.jgroups.protocols;
import org.jgroups.*;
import org.jgroups.stack.GossipClient;
import org.jgroups.stack.IpAddress;
import org.jgroups.util.Util;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.*;
/**
* The PING protocol layer retrieves the initial membership (used by the GMS when started
* by sending event FIND_INITIAL_MBRS down the stack). We do this by mcasting PING
* requests to an IP MCAST address (or, if gossiping is enabled, by contacting the GossipRouter).
* The responses should allow us to determine the coordinator whom we have to
* contact, e.g. in case we want to join the group. When we are a server (after having
* received the BECOME_SERVER event), we'll respond to PING requests with a PING
* response.<p> The FIND_INITIAL_MBRS event will eventually be answered with a
* FIND_INITIAL_MBRS_OK event up the stack.
* The following properties are available
* property: gossip_host - if you are using GOSSIP then this defines the host of the GossipRouter, default is null
* property: gossip_port - if you are using GOSSIP then this defines the port of the GossipRouter, default is null
* @author Bela Ban
* @version $Id: PING.java,v 1.36.2.2 2008/02/06 11:52:56 belaban Exp $
*/
public class PING extends Discovery {
String gossip_host=null;
Vector<IpAddress> gossip_hosts=null;
int gossip_port=0;
long gossip_refresh=20000; // time in msecs after which the entry in GossipRouter will be refreshed
GossipClient client;
int port_range=1; // number of ports to be probed for initial membership
private List<Address> initial_hosts=null; // hosts to be contacted for the initial membership
public static final String name="PING";
public String getName() {
return name;
}
/**
* sets the properties of the PING protocol.
* The following properties are available
* property: timeout - the timeout (ms) to wait for the initial members, default is 3000=3 secs
* property: num_initial_members - the minimum number of initial members for a FIND_INITAL_MBRS, default is 2
* property: gossip_host - if you are using GOSSIP then this defines the host of the GossipRouter, default is null
* property: gossip_port - if you are using GOSSIP then this defines the port of the GossipRouter, default is null
*
* @param props - a property set containing only PING properties
* @return returns true if all properties were parsed properly
* returns false if there are unrecnogized properties in the property set
*/
public boolean setProperties(Properties props) {
String str;
str=props.getProperty("gossip_host");
if(str != null) {
gossip_host=str;
props.remove("gossip_host");
}
str=props.getProperty("gossip_hosts");
if(str != null) {
try {
gossip_hosts=createInitialHosts(str);
}
catch(UnknownHostException e) {
throw new IllegalArgumentException(e);
}
props.remove("gossip_hosts");
}
str=props.getProperty("gossip_port");
if(str != null) {
gossip_port=Integer.parseInt(str);
props.remove("gossip_port");
}
str=props.getProperty("gossip_refresh");
if(str != null) {
gossip_refresh=Long.parseLong(str);
props.remove("gossip_refresh");
}
if(gossip_hosts != null) {
client=new GossipClient(gossip_hosts, gossip_refresh);
}
else if(gossip_host != null && gossip_port != 0) {
try {
client=new GossipClient(new IpAddress(InetAddress.getByName(gossip_host), gossip_port), gossip_refresh);
}
catch(Exception e) {
if(log.isErrorEnabled()) log.error("creation of GossipClient failed, exception=" + e);
return false; // will cause stack creation to abort
}
}
str=props.getProperty("port_range"); // if member cannot be contacted on base port,
if(str != null) { // how many times can we increment the port
port_range=Integer.parseInt(str);
if(port_range < 1) {
port_range=1;
}
props.remove("port_range");
}
str=props.getProperty("initial_hosts");
if(str != null) {
props.remove("initial_hosts");
try {
initial_hosts=new ArrayList<Address>();
List<IpAddress> tmp=createInitialHosts(str);
initial_hosts.addAll(tmp);
}
catch(UnknownHostException e) {
if(log.isErrorEnabled())
log.error("failed constructing initial list of hosts", e);
return false;
}
}
return super.setProperties(props);
}
public void stop() {
super.stop();
if(client != null) {
client.stop();
}
}
public void localAddressSet(Address addr) {
// Add own address to initial_hosts if not present: we must always be able to ping ourself !
if(initial_hosts != null && addr != null) {
if(initial_hosts.contains(addr)) {
initial_hosts.remove(addr);
if(log.isDebugEnabled()) log.debug("[SET_LOCAL_ADDRESS]: removing my own address (" + addr +
") from initial_hosts; initial_hosts=" + initial_hosts);
}
}
}
public void handleConnect() {
if(client != null)
client.register(group_addr, local_addr);
}
public void handleDisconnect() {
if(client != null)
client.stop();
}
public void sendGetMembersRequest() {
Message msg;
PingHeader hdr;
List<Address> gossip_rsps;
if(client != null) {
gossip_rsps=client.getMembers(group_addr);
if(gossip_rsps != null && !gossip_rsps.isEmpty()) {
// Set a temporary membership in the UDP layer, so that the following multicast
// will be sent to all of them
Event view_event=new Event(Event.TMP_VIEW, makeView(new Vector<Address>(gossip_rsps)));
down_prot.down(view_event); // needed e.g. by failure detector or UDP
}
else {
//do nothing
return;
}
if(!gossip_rsps.isEmpty()) {
for(Iterator<Address> it=gossip_rsps.iterator(); it.hasNext();) {
Address dest=it.next();
msg=new Message(dest, null, null); // unicast msg
msg.setFlag(Message.OOB);
msg.putHeader(getName(), new PingHeader(PingHeader.GET_MBRS_REQ, null));
down_prot.down(new Event(Event.MSG, msg));
}
}
Util.sleep(500);
}
else {
if(initial_hosts != null && !initial_hosts.isEmpty()) {
for(Address addr: initial_hosts) {
// if(tmpMbrs.contains(addr)) {
// ; // continue; // changed as suggested by Mark Kopec
// }
msg=new Message(addr, null, null);
msg.setFlag(Message.OOB);
msg.putHeader(name, new PingHeader(PingHeader.GET_MBRS_REQ, null));
if(log.isTraceEnabled()) log.trace("[FIND_INITIAL_MBRS] sending PING request to " + msg.getDest());
down_prot.down(new Event(Event.MSG, msg));
}
}
else {
// 1. Mcast GET_MBRS_REQ message
hdr=new PingHeader(PingHeader.GET_MBRS_REQ, null);
msg=new Message(null); // mcast msg
msg.setFlag(Message.OOB);
msg.putHeader(getName(), hdr); // needs to be getName(), so we might get "MPING" !
sendMcastDiscoveryRequest(msg);
}
}
}
void sendMcastDiscoveryRequest(Message discovery_request) {
down_prot.down(new Event(Event.MSG, discovery_request));
}
/* -------------------------- Private methods ---------------------------- */
/**
* Input is "daddy[8880],sindhu[8880],camille[5555]. Return List of IpAddresses
*/
private Vector<IpAddress> createInitialHosts(String l) throws UnknownHostException {
StringTokenizer tok=new StringTokenizer(l, ",");
String t;
IpAddress addr;
Vector<IpAddress> retval=new Vector<IpAddress>();
while(tok.hasMoreTokens()) {
try {
t=tok.nextToken().trim();
String host=t.substring(0, t.indexOf('['));
host=host.trim();
int port=Integer.parseInt(t.substring(t.indexOf('[') + 1, t.indexOf(']')));
for(int i=port; i < port + port_range; i++) {
addr=new IpAddress(host, i);
retval.add(addr);
}
}
catch(NumberFormatException e) {
if(log.isErrorEnabled()) log.error("exeption is " + e);
}
}
return retval;
}
}