package org.jgroups.protocols;
import org.jgroups.*;
import org.jgroups.annotations.GuardedBy;
import org.jgroups.stack.IpAddress;
import org.jgroups.stack.Protocol;
import org.jgroups.util.*;
import org.jgroups.util.ThreadFactory;
import java.io.*;
import java.net.*;
import java.util.*;
import java.util.concurrent.*;
/**
* Failure detection protocol based on sockets. Failure detection is ring-based. Each member creates a
* server socket and announces its address together with the server socket's address in a multicast. A
* pinger thread will be started when the membership goes above 1 and will be stopped when it drops below
* 2. The pinger thread connects to its neighbor on the right and waits until the socket is closed. When
* the socket is closed by the monitored peer in an abnormal fashion (IOException), the neighbor will be
* suspected.<p> The main feature of this protocol is that no ping messages need to be exchanged between
* any 2 peers, and failure detection relies entirely on TCP sockets. The advantage is that no activity
* will take place between 2 peers as long as they are alive (i.e. have their server sockets open).
* The disadvantage is that hung servers or crashed routers will not cause sockets to be closed, therefore
* they won't be detected.
* The FD_SOCK protocol will work for groups where members are on different hosts<p>
* The costs involved are 2 additional threads: one that
* monitors the client side of the socket connection (to monitor a peer) and another one that manages the
* server socket. However, those threads will be idle as long as both peers are running.
* @author Bela Ban May 29 2001
* @version $Id: FD_SOCK.java,v 1.83.2.9 2009/09/29 04:36:30 belaban Exp $
*/
public class FD_SOCK extends Protocol implements Runnable {
long get_cache_timeout=1000; // msecs to wait for the socket cache from the coordinator
long suspect_msg_interval=5000; // (BroadcastTask): mcast SUSPECT every 5000 msecs
int num_tries=3; // attempts coord is solicited for socket cache until we give up
final Vector<Address> members=new Vector<Address>(11); // list of group members (updated on VIEW_CHANGE)
boolean srv_sock_sent=false; // has own socket been broadcast yet ?
/** Used to rendezvous on GET_CACHE and GET_CACHE_RSP */
final Promise<Map<Address,IpAddress>> get_cache_promise=new Promise<Map<Address,IpAddress>>();
boolean got_cache_from_coord=false; // was cache already fetched ?
Address local_addr=null; // our own address
ServerSocket srv_sock=null; // server socket to which another member connects to monitor me
InetAddress bind_addr=null; // the NIC on which the ServerSocket should listen
private ServerSocketHandler srv_sock_handler=null; // accepts new connections on srv_sock
IpAddress srv_sock_addr=null; // pair of server_socket:port
Address ping_dest=null; // address of the member we monitor
Socket ping_sock=null; // socket to the member we monitor
InputStream ping_input=null; // input stream of the socket to the member we monitor
@GuardedBy("this")
volatile Thread pinger_thread=null; // listens on ping_sock, suspects member if socket is closed
/** Cache of member addresses and their ServerSocket addresses */
final ConcurrentMap<Address,IpAddress> cache=new ConcurrentHashMap<Address,IpAddress>(11);
/** Start port for server socket (uses first available port starting at start_port). A value of 0 (default)
* picks a random port */
int start_port=0;
final Promise<IpAddress> ping_addr_promise=new Promise<IpAddress>(); // to fetch the ping_addr for ping_dest
final Object sock_mutex=new Object(); // for access to ping_sock, ping_input
TimeScheduler timer=null;
private final BroadcastTask bcast_task=new BroadcastTask(); // to transmit SUSPECT message (until view change)
boolean regular_sock_close=false; // used by interruptPingerThread() when new ping_dest is computed
int num_suspect_events=0;
private static final int INTERRUPT =8;
private static final int NORMAL_TERMINATION=9;
private static final int ABNORMAL_TERMINATION=-1;
private static final String name="FD_SOCK";
final BoundedList<Address> suspect_history=new BoundedList<Address>(20);
/** whether to use KEEP_ALIVE on the ping socket or not */
private boolean keep_alive=true;
private int sock_conn_timeout=3000; // max time in millis to wait for Socket.connect() to return
private volatile boolean running=false;
public String getName() {
return name;
}
public String getLocalAddress() {return local_addr != null? local_addr.toString() : "null";}
public String getMembers() {return members != null? members.toString() : "null";}
public String getPingableMembers() {return getMembers();}
public String getPingDest() {return ping_dest != null? ping_dest.toString() : "null";}
public int getNumSuspectEventsGenerated() {return num_suspect_events;}
public String printSuspectHistory() {
StringBuilder sb=new StringBuilder();
for(Address suspect: suspect_history) {
sb.append(new Date()).append(": ").append(suspect).append("\n");
}
return sb.toString();
}
public boolean setProperties(Properties props) {
String str;
super.setProperties(props);
str=props.getProperty("get_cache_timeout");
if(str != null) {
get_cache_timeout=Long.parseLong(str);
props.remove("get_cache_timeout");
}
str=props.getProperty("suspect_msg_interval");
if(str != null) {
suspect_msg_interval=Long.parseLong(str);
props.remove("suspect_msg_interval");
}
str=props.getProperty("num_tries");
if(str != null) {
num_tries=Integer.parseInt(str);
props.remove("num_tries");
}
str=props.getProperty("start_port");
if(str != null) {
start_port=Integer.parseInt(str);
props.remove("start_port");
}
str=props.getProperty("keep_alive");
if(str != null) {
keep_alive=Boolean.parseBoolean(str);
props.remove("keep_alive");
}
str=props.getProperty("srv_sock_bind_addr");
if(str != null) {
log.error("srv_sock_bind_addr is deprecated and will be ignored - use bind_addr instead");
props.remove("srv_sock_bind_addr");
}
str=props.getProperty("sock_conn_timeout");
if(str != null) {
sock_conn_timeout=Integer.parseInt(str);
props.remove("sock_conn_timeout");
}
try {
bind_addr=Util.getBindAddress(props);
}
catch(UnknownHostException unknown) {
log.fatal("failed getting bind_addr", unknown);
return false;
}
catch(SocketException ex) {
log.fatal("failed getting bind_addr", ex);
return false;
}
if(!props.isEmpty()) {
log.error("the following properties are not recognized: " + props);
return false;
}
return true;
}
public String printCache() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,IpAddress> entry: cache.entrySet()) {
sb.append(entry.getKey()).append(" has server socket at ").append(entry.getValue()).append("\n");
}
return sb.toString();
}
public void init() throws Exception {
srv_sock_handler=new ServerSocketHandler();
timer=getTransport().getTimer();
if(timer == null)
throw new Exception("timer is null");
}
public void start() throws Exception {
super.start();
startServerSocket();
running=true;
}
public void stop() {
running=false;
bcast_task.removeAll();
synchronized(this) {
stopPingerThread();
}
stopServerSocket(true); // graceful close
}
public void resetStats() {
super.resetStats();
num_suspect_events=0;
suspect_history.clear();
}
public Object up(Event evt) {
switch(evt.getType()) {
case Event.SET_LOCAL_ADDRESS:
local_addr=(Address) evt.getArg();
break;
case Event.MSG:
Message msg=(Message) evt.getArg();
FdHeader hdr=(FdHeader)msg.getHeader(name);
if(hdr == null)
break; // message did not originate from FD_SOCK layer, just pass up
switch(hdr.type) {
case FdHeader.SUSPECT:
if(hdr.mbrs != null) {
if(log.isDebugEnabled()) log.debug("[SUSPECT] hdr=" + hdr);
for(Address m: hdr.mbrs) {
if(local_addr != null && m.equals(local_addr)) {
if(log.isWarnEnabled())
log.warn("I was suspected by " + msg.getSrc() + "; ignoring the SUSPECT message");
continue;
}
up_prot.up(new Event(Event.SUSPECT, m));
down_prot.down(new Event(Event.SUSPECT, m));
}
}
else
if(log.isWarnEnabled()) log.warn("[SUSPECT]: hdr.mbrs == null");
break;
// If I have the sock for 'hdr.mbr', return it. Otherwise look it up in my cache and return it
case FdHeader.WHO_HAS_SOCK:
if(local_addr != null && local_addr.equals(msg.getSrc()))
return null; // don't reply to WHO_HAS bcasts sent by me !
if(hdr.mbr == null) {
if(log.isErrorEnabled()) log.error("hdr.mbr is null");
return null;
}
if(log.isTraceEnabled()) log.trace("who-has-sock " + hdr.mbr);
// 1. Try my own address, maybe it's me whose socket is wanted
if(local_addr != null && local_addr.equals(hdr.mbr) && srv_sock_addr != null) {
sendIHaveSockMessage(msg.getSrc(), local_addr, srv_sock_addr); // unicast message to msg.getSrc()
return null;
}
// 2. If I don't have it, maybe it is in the cache
IpAddress addr=cache.get(hdr.mbr);
if(addr != null)
sendIHaveSockMessage(msg.getSrc(), hdr.mbr, addr); // ucast msg
break;
// Update the cache with the addr:sock_addr entry (if on the same host)
case FdHeader.I_HAVE_SOCK:
if(hdr.mbr == null || hdr.sock_addr == null) {
if(log.isErrorEnabled()) log.error("[I_HAVE_SOCK]: hdr.mbr is null or hdr.sock_addr == null");
return null;
}
// if(!cache.containsKey(hdr.mbr))
cache.put(hdr.mbr, hdr.sock_addr); // update the cache
if(log.isTraceEnabled()) log.trace("i-have-sock: " + hdr.mbr + " --> " +
hdr.sock_addr + " (cache is " + cache + ')');
if(ping_dest != null && hdr.mbr.equals(ping_dest))
ping_addr_promise.setResult(hdr.sock_addr);
break;
// Return the cache to the sender of this message
case FdHeader.GET_CACHE:
Address sender=msg.getSrc(); // guaranteed to be non-null
hdr=new FdHeader(FdHeader.GET_CACHE_RSP,new HashMap<Address,IpAddress>(cache));
msg=new Message(sender, null, null);
msg.setFlag(Message.OOB);
msg.putHeader(name, hdr);
down_prot.down(new Event(Event.MSG, msg));
break;
case FdHeader.GET_CACHE_RSP:
if(hdr.cachedAddrs == null) {
if(log.isWarnEnabled()) log.warn("(GET_CACHE_RSP): cache is null");
return null;
}
get_cache_promise.setResult(hdr.cachedAddrs);
break;
}
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");
}
break;
}
return up_prot.up(evt); // pass up to the layer above us
}
public Object down(Event evt) {
switch(evt.getType()) {
case Event.UNSUSPECT:
bcast_task.removeSuspectedMember((Address)evt.getArg());
break;
case Event.DISCONNECT:
stopServerSocket(true); // graceful close
break;
case Event.SHUTDOWN:
stopServerSocket(false);
break;
case Event.VIEW_CHANGE:
View v=(View) evt.getArg();
final Vector<Address> new_mbrs=v.getMembers();
Runnable reshuffleSockets=new Runnable() {
public void run() {
synchronized(FD_SOCK.this) {
members.removeAllElements();
members.addAll(new_mbrs);
cache.keySet().retainAll(members); // remove all entries in 'cache' which are not in the new membership
bcast_task.adjustSuspectedMembers(members);
if(log.isDebugEnabled()) log.debug("VIEW_CHANGE received: " + members);
if(members.size() > 1) {
if(pinger_thread != null && pinger_thread.isAlive()) {
Address tmp_ping_dest=determinePingDest();
if(ping_dest != null && tmp_ping_dest != null && !ping_dest.equals(tmp_ping_dest)) {
interruptPingerThread(); // allows the thread to use the new socket
}
}
else
startPingerThread(); // only starts if not yet running
}
else {
ping_dest=null;
stopPingerThread();
}
}
}
};
timer.execute(reshuffleSockets);
break;
default:
return down_prot.down(evt);
}
return down_prot.down(evt);
}
/**
* Runs as long as there are 2 members and more. Determines the member to be monitored and fetches its
* server socket address (if n/a, sends a message to obtain it). The creates a client socket and listens on
* it until the connection breaks. If it breaks, emits a SUSPECT message. It the connection is closed regularly,
* nothing happens. In both cases, a new member to be monitored will be chosen and monitoring continues (unless
* there are fewer than 2 members).
*/
public void run() {
if(log.isTraceEnabled()) log.trace("pinger_thread started");
// 1. Broadcast my own addr:sock to all members so they can update their cache
if(!srv_sock_sent) {
if(srv_sock_addr != null) {
sendIHaveSockMessage(null, // send to all members
local_addr,
srv_sock_addr);
srv_sock_sent=true;
}
else
if(log.isWarnEnabled()) log.warn("(VIEW_CHANGE): srv_sock_addr == null");
}
// 2. Get the addr:pid cache from the coordinator (only if not already fetched)
if(!got_cache_from_coord) {
getCacheFromCoordinator();
got_cache_from_coord=true;
}
while(pinger_thread != null && Thread.currentThread().equals(pinger_thread) && running) {
ping_dest=determinePingDest(); // gets the neighbor to our right
if(log.isDebugEnabled())
log.debug("determinePingDest()=" + ping_dest);
if(ping_dest == null) {
break;
}
IpAddress ping_addr=fetchPingAddress(ping_dest);
if(ping_addr == null) {
if(!running)
break;
if(log.isErrorEnabled()) log.error("socket address for " + ping_dest + " could not be fetched, retrying");
Util.sleep(1000);
continue;
}
if(!setupPingSocket(ping_addr)) {
// covers use cases #7 and #8 in ManualTests.txt
if(log.isDebugEnabled()) log.debug("could not create socket to " + ping_dest + "; suspecting " + ping_dest);
broadcastSuspectMessage(ping_dest);
continue;
}
if(log.isDebugEnabled()) log.debug("ping_dest=" + ping_dest + ", ping_sock=" + ping_sock + ", cache=" + cache);
// at this point ping_input must be non-null, otherwise setupPingSocket() would have thrown an exception
try {
if(ping_input != null) {
int c=ping_input.read();
switch(c) {
case NORMAL_TERMINATION:
if(log.isDebugEnabled())
log.debug("peer closed socket normally");
synchronized(this) {
pinger_thread=null;
}
break;
case ABNORMAL_TERMINATION:
handleSocketClose(null);
break;
default:
break;
}
}
}
catch(IOException ex) { // we got here when the peer closed the socket --> suspect peer and then continue
handleSocketClose(ex);
}
catch(Throwable catch_all_the_rest) {
log.error("exception", catch_all_the_rest);
}
}
if(log.isDebugEnabled()) log.debug("pinger thread terminated");
synchronized(this) {
pinger_thread=null;
}
}
/* ----------------------------------- Private Methods -------------------------------------- */
void handleSocketClose(Exception ex) {
teardownPingSocket(); // make sure we have no leftovers
if(!regular_sock_close) { // only suspect if socket was not closed regularly (by interruptPingerThread())
if(log.isDebugEnabled())
log.debug("peer " + ping_dest + " closed socket (" + (ex != null ? ex.getClass().getName() : "eof") + ')');
broadcastSuspectMessage(ping_dest);
}
else {
if(log.isDebugEnabled()) log.debug("socket to " + ping_dest + " was reset");
regular_sock_close=false;
}
}
/**
* Does *not* need to be synchronized on pinger_mutex because the caller (down()) already has the mutex acquired
*/
void startPingerThread() {
running=true;
if(pinger_thread == null) {
ThreadFactory factory=getThreadFactory();
pinger_thread=factory.newThread(this, "FD_SOCK pinger");
pinger_thread.setDaemon(true);
pinger_thread.start();
}
}
void stopPingerThread() {
running=false;
if(pinger_thread != null && pinger_thread.isAlive()) {
regular_sock_close=true;
pinger_thread=null;
sendPingTermination(); // PATCH by Bruce Schuchardt (http://jira.jboss.com/jira/browse/JGRP-246)
teardownPingSocket();
ping_addr_promise.setResult(null);
get_cache_promise.setResult(null);
}
}
// PATCH: send something so the connection handler can exit
void sendPingTermination() {
sendPingSignal(NORMAL_TERMINATION);
}
void sendPingInterrupt() {
sendPingSignal(INTERRUPT);
}
void sendPingSignal(int signal) {
synchronized(sock_mutex) {
if(ping_sock != null) {
try {
OutputStream out=ping_sock.getOutputStream();
if(out != null) {
out.write(signal);
out.flush();
}
}
catch(Throwable t) {
if(log.isTraceEnabled())
log.trace("problem sending signal " + signalToString(signal), t);
}
}
}
}
/**
* Interrupts the pinger thread. The Thread.interrupt() method doesn't seem to work under Linux with JDK 1.3.1
* (JDK 1.2.2 had no problems here), therefore we close the socket (setSoLinger has to be set !) if we are
* running under Linux. This should be tested under Windows. (Solaris 8 and JDK 1.3.1 definitely works).<p>
* Oct 29 2001 (bela): completely removed Thread.interrupt(), but used socket close on all OSs. This makes this
* code portable and we don't have to check for OSs.<p/>
* Does *not* need to be synchronized on pinger_mutex because the caller (down()) already has the mutex acquired
* @see {@link org.jgroups.tests.InterruptTest} to determine whether Thread.interrupt() works for InputStream.read().
*/
void interruptPingerThread() {
if(pinger_thread != null && pinger_thread.isAlive()) {
regular_sock_close=true;
sendPingInterrupt(); // PATCH by Bruce Schuchardt (http://jira.jboss.com/jira/browse/JGRP-246)
teardownPingSocket(); // will wake up the pinger thread. less elegant than Thread.interrupt(), but does the job
}
}
void startServerSocket() throws IOException {
srv_sock=Util.createServerSocket(bind_addr, start_port); // grab a random unused port above 10000
srv_sock_addr=new IpAddress(bind_addr, srv_sock.getLocalPort());
if(srv_sock_handler != null) {
srv_sock_handler.start(); // won't start if already running
}
}
void stopServerSocket(boolean graceful) {
if(srv_sock_handler != null)
srv_sock_handler.stop(graceful);
}
/**
* Creates a socket to <code>dest</code>, and assigns it to ping_sock. Also assigns ping_input
*/
boolean setupPingSocket(IpAddress dest) {
synchronized(sock_mutex) {
if(dest == null) {
if(log.isErrorEnabled()) log.error("destination address is null");
return false;
}
try {
SocketAddress destAddr=new InetSocketAddress(dest.getIpAddress(), dest.getPort());
ping_sock=new Socket();
ping_sock.setSoLinger(true, 1);
ping_sock.setKeepAlive(keep_alive);
ping_sock.connect(destAddr, sock_conn_timeout);
ping_input=ping_sock.getInputStream();
return true;
}
catch(Throwable ex) {
return false;
}
}
}
void teardownPingSocket() {
synchronized(sock_mutex) {
if(ping_sock != null) {
try {
ping_sock.shutdownInput();
ping_sock.close();
}
catch(Exception ex) {
}
ping_sock=null;
}
Util.close(ping_input);
ping_input=null;
}
}
/**
* Determines coordinator C. If C is null and we are the first member, return. Else loop: send GET_CACHE message
* to coordinator and wait for GET_CACHE_RSP response. Loop until valid response has been received.
*/
void getCacheFromCoordinator() {
Address coord;
int attempts=num_tries;
Message msg;
FdHeader hdr;
Map<Address,IpAddress> result;
get_cache_promise.reset();
while(attempts > 0 && running) {
if((coord=determineCoordinator()) != null) {
if(coord.equals(local_addr)) { // we are the first member --> empty cache
if(log.isDebugEnabled()) log.debug("first member; cache is empty");
return;
}
hdr=new FdHeader(FdHeader.GET_CACHE);
msg=new Message(coord, null, null);
msg.setFlag(Message.OOB);
msg.putHeader(name, hdr);
down_prot.down(new Event(Event.MSG, msg));
result=get_cache_promise.getResult(get_cache_timeout);
if(result != null) {
cache.putAll(result);
if(log.isTraceEnabled()) log.trace("got cache from " + coord + ": cache is " + cache);
return;
}
else {
if(log.isWarnEnabled()) log.warn("received null cache; retrying");
}
}
--attempts;
}
}
/**
* Sends a SUSPECT message to all group members. Only the coordinator (or the next member in line if the coord
* itself is suspected) will react to this message by installing a new view. To overcome the unreliability
* of the SUSPECT message (it may be lost because we are not above any retransmission layer), the following scheme
* is used: after sending the SUSPECT message, it is also added to the broadcast task, which will periodically
* re-send the SUSPECT until a view is received in which the suspected process is not a member anymore. The reason is
* that - at one point - either the coordinator or another participant taking over for a crashed coordinator, will
* react to the SUSPECT message and issue a new view, at which point the broadcast task stops.
*/
void broadcastSuspectMessage(Address suspected_mbr) {
Message suspect_msg;
FdHeader hdr;
if(suspected_mbr == null) return;
if(log.isTraceEnabled()) log.trace("suspecting " + suspected_mbr + " (own address is " + local_addr + ')');
// 1. Send a SUSPECT message right away; the broadcast task will take some time to send it (sleeps first)
hdr=new FdHeader(FdHeader.SUSPECT);
hdr.mbrs=new HashSet<Address>(1);
hdr.mbrs.add(suspected_mbr);
suspect_msg=new Message();
suspect_msg.setFlag(Message.OOB);
suspect_msg.putHeader(name, hdr);
down_prot.down(new Event(Event.MSG, suspect_msg));
// 2. Add to broadcast task and start latter (if not yet running). The task will end when
// suspected members are removed from the membership
bcast_task.addSuspectedMember(suspected_mbr);
if(stats) {
num_suspect_events++;
suspect_history.add(suspected_mbr);
}
}
/**
Sends or broadcasts a I_HAVE_SOCK response. If 'dst' is null, the reponse will be broadcast, otherwise
it will be unicast back to the requester
*/
void sendIHaveSockMessage(Address dst, Address mbr, IpAddress addr) {
Message msg=new Message(dst, null, null);
msg.setFlag(Message.OOB);
FdHeader hdr=new FdHeader(FdHeader.I_HAVE_SOCK);
hdr.mbr=mbr;
hdr.sock_addr=addr;
msg.putHeader(name, hdr);
down_prot.down(new Event(Event.MSG, msg));
}
/**
Attempts to obtain the ping_addr first from the cache, then by unicasting q request to <code>mbr</code>,
then by multicasting a request to all members.
*/
private IpAddress fetchPingAddress(Address mbr) {
IpAddress ret;
Message ping_addr_req;
FdHeader hdr;
if(mbr == null) {
if(log.isErrorEnabled()) log.error("mbr == null");
return null;
}
// 1. Try to get the server socket address from the cache
if((ret=cache.get(mbr)) != null)
return ret;
// 2. Try to get the server socket address from mbr
ping_addr_promise.reset();
ping_addr_req=new Message(mbr, null, null); // unicast
ping_addr_req.setFlag(Message.OOB);
hdr=new FdHeader(FdHeader.WHO_HAS_SOCK);
hdr.mbr=mbr;
ping_addr_req.putHeader(name, hdr);
down_prot.down(new Event(Event.MSG, ping_addr_req));
if(!running) return null;
ret=ping_addr_promise.getResult(500);
if(ret != null) {
return ret;
}
// 3. Try to get the server socket address from all members
ping_addr_req=new Message(null); // multicast
ping_addr_req.setFlag(Message.OOB);
hdr=new FdHeader(FdHeader.WHO_HAS_SOCK);
hdr.mbr=mbr;
ping_addr_req.putHeader(name, hdr);
down_prot.down(new Event(Event.MSG, ping_addr_req));
ret=ping_addr_promise.getResult(500);
return ret;
}
private synchronized Address determinePingDest() {
Vector<Address> non_suspected_mbrs=new Vector<Address>(members);
non_suspected_mbrs.removeAll(bcast_task.getSuspectedMembers());
return determineRightNeighbor(non_suspected_mbrs);
}
private synchronized Address determineRightNeighbor(Vector<Address> list) {
Address result=null;
if(list.size() > 1 && local_addr != null) {
if(local_addr.equals(list.lastElement())) {
result=list.firstElement();
}
else {
int myIndex=list.indexOf(local_addr);
if(myIndex != -1){
result=list.get(myIndex + 1);
}
}
}
return result;
}
Address determineCoordinator() {
return !members.isEmpty()? members.elementAt(0) : null;
}
static String signalToString(int signal) {
switch(signal) {
case NORMAL_TERMINATION: return "NORMAL_TERMINATION";
case ABNORMAL_TERMINATION: return "ABNORMAL_TERMINATION";
case INTERRUPT: return "INTERRUPT";
default: return "n/a";
}
}
/* ------------------------------- End of Private Methods ------------------------------------ */
public static class FdHeader extends Header implements Streamable {
public static final byte SUSPECT=10;
public static final byte WHO_HAS_SOCK=11;
public static final byte I_HAVE_SOCK=12;
public static final byte GET_CACHE=13; // sent by joining member to coordinator
public static final byte GET_CACHE_RSP=14; // sent by coordinator to joining member in response to GET_CACHE
byte type=SUSPECT;
Address mbr=null; // set on WHO_HAS_SOCK (requested mbr), I_HAVE_SOCK
IpAddress sock_addr; // set on I_HAVE_SOCK
Map<Address,IpAddress> cachedAddrs=null; // set on GET_CACHE_RSP
Set<Address> mbrs=null; // set on SUSPECT (list of suspected members)
private static final long serialVersionUID=-7025890133989522764L;
public FdHeader() {
} // used for externalization
public FdHeader(byte type) {
this.type=type;
}
public FdHeader(byte type, Address mbr) {
this.type=type;
this.mbr=mbr;
}
public FdHeader(byte type, Address mbr, IpAddress sock_addr) {
this.type=type;
this.mbr=mbr;
this.sock_addr = sock_addr ;
}
public FdHeader(byte type, Set<Address> mbrs) {
this.type=type;
this.mbrs=mbrs;
}
public FdHeader(byte type, Map<Address,IpAddress> cachedAddrs) {
this.type=type;
this.cachedAddrs=cachedAddrs;
}
public String toString() {
StringBuilder sb=new StringBuilder();
sb.append(type2String(type));
if(mbr != null)
sb.append(", mbr=").append(mbr);
if(sock_addr != null)
sb.append(", sock_addr=").append(sock_addr);
if(cachedAddrs != null)
sb.append(", cache=").append(cachedAddrs);
if(mbrs != null)
sb.append(", mbrs=").append(mbrs);
return sb.toString();
}
public static String type2String(byte type) {
switch(type) {
case SUSPECT:
return "SUSPECT";
case WHO_HAS_SOCK:
return "WHO_HAS_SOCK";
case I_HAVE_SOCK:
return "I_HAVE_SOCK";
case GET_CACHE:
return "GET_CACHE";
case GET_CACHE_RSP:
return "GET_CACHE_RSP";
default:
return "unknown type (" + type + ')';
}
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeByte(type);
out.writeObject(mbr);
out.writeObject(sock_addr);
out.writeObject(cachedAddrs);
out.writeObject(mbrs);
}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
type=in.readByte();
mbr=(Address)in.readObject();
sock_addr=(IpAddress)in.readObject();
cachedAddrs=(Map<Address,IpAddress>)in.readObject();
mbrs=(Set<Address>)in.readObject();
}
public int size() {
int retval=Global.BYTE_SIZE; // type
retval+=Util.size(mbr);
// use of Util.size(Address) with IpAddress overestimates size by one byte.
// replace: retval+=Util.size(sock_addr); with the following:
int ipaddr_size = 0 ;
ipaddr_size += Global.BYTE_SIZE ; // presence byte
if (sock_addr != null)
ipaddr_size += sock_addr.size(); // IpAddress size
retval += ipaddr_size ;
retval+=Global.INT_SIZE; // cachedAddrs size
Address key;
IpAddress val;
if(cachedAddrs != null) {
for(Map.Entry<Address,IpAddress> entry: cachedAddrs.entrySet()) {
if((key=entry.getKey()) != null)
retval+=Util.size(key);
retval+=Global.BYTE_SIZE; // presence for val
if((val=entry.getValue()) != null)
retval+=val.size();
}
}
retval+=Global.INT_SIZE; // mbrs size
if(mbrs != null) {
for(Address m: mbrs) {
retval+=Util.size(m);
}
}
return retval;
}
public void writeTo(DataOutputStream out) throws IOException {
int size;
out.writeByte(type);
Util.writeAddress(mbr, out);
Util.writeStreamable(sock_addr, out);
size=cachedAddrs != null? cachedAddrs.size() : 0;
out.writeInt(size);
if(size > 0) {
for(Map.Entry<Address,IpAddress> entry: cachedAddrs.entrySet()) {
Address key=entry.getKey();
IpAddress val=entry.getValue();
Util.writeAddress(key, out);
Util.writeStreamable(val, out);
}
}
size=mbrs != null? mbrs.size() : 0;
out.writeInt(size);
if(size > 0) {
for(Address address: mbrs) {
Util.writeAddress(address, out);
}
}
}
public void readFrom(DataInputStream in) throws IOException, IllegalAccessException, InstantiationException {
int size;
type=in.readByte();
mbr=Util.readAddress(in);
sock_addr=(IpAddress)Util.readStreamable(IpAddress.class, in);
size=in.readInt();
if(size > 0) {
if(cachedAddrs == null)
cachedAddrs=new HashMap<Address,IpAddress>(size);
for(int i=0; i < size; i++) {
Address key=Util.readAddress(in);
IpAddress val=(IpAddress)Util.readStreamable(IpAddress.class, in);
cachedAddrs.put(key, val);
}
}
size=in.readInt();
if(size > 0) {
if(mbrs == null)
mbrs=new HashSet<Address>();
for(int i=0; i < size; i++) {
Address addr=Util.readAddress(in);
mbrs.add(addr);
}
}
}
}
/**
* Handles the server-side of a client-server socket connection. Waits until a client connects, and then loops
* until that client closes the connection. Note that there is no new thread spawned for the listening on the
* client socket, therefore there can only be 1 client connection at the same time. Subsequent clients attempting
* to create a connection will be blocked until the first client closes its connection. This should not be a problem
* as the ring nature of the FD_SOCK protocol always has only 1 client connect to its right-hand-side neighbor.
*/
private class ServerSocketHandler implements Runnable {
Thread acceptor=null;
/** List<ClientConnectionHandler> */
final List<ClientConnectionHandler> clients=new LinkedList<ClientConnectionHandler>();
ServerSocketHandler() {
start();
}
final void start() {
if(acceptor == null) {
acceptor=getThreadFactory().newThread(this, "FD_SOCK server socket acceptor");
acceptor.setDaemon(true);
acceptor.start();
}
}
final void stop(boolean graceful) {
if(acceptor != null && acceptor.isAlive()) {
try {
srv_sock.close(); // this will terminate thread, peer will receive SocketException (socket close)
}
catch(Exception ex) {
}
}
synchronized(clients) {
for(ClientConnectionHandler handler: clients) {
handler.stopThread(graceful);
}
clients.clear();
}
acceptor=null;
}
/** Only accepts 1 client connection at a time (saving threads) */
public void run() {
Socket client_sock;
while(acceptor != null && srv_sock != null) {
try {
if(log.isTraceEnabled()) // +++ remove
log.trace("waiting for client connections on " + srv_sock.getInetAddress() + ":" +
srv_sock.getLocalPort());
client_sock=srv_sock.accept();
if(log.isTraceEnabled()) // +++ remove
log.trace("accepted connection from " + client_sock.getInetAddress() + ':' + client_sock.getPort());
ClientConnectionHandler client_conn_handler=new ClientConnectionHandler(client_sock, clients);
Thread t = getThreadFactory().newThread(client_conn_handler, "FD_SOCK client connection handler");
t.setDaemon(true);
synchronized(clients) {
clients.add(client_conn_handler);
}
t.start();
}
catch(IOException io_ex2) {
break;
}
}
acceptor=null;
}
}
/** Handles a client connection; multiple client can connect at the same time */
private static class ClientConnectionHandler implements Runnable {
Socket client_sock=null;
InputStream in;
final Object mutex=new Object();
final List<ClientConnectionHandler> clients;
ClientConnectionHandler(Socket client_sock, List<ClientConnectionHandler> clients) {
this.client_sock=client_sock;
this.clients=clients;
}
void stopThread(boolean graceful) {
synchronized(mutex) {
if(client_sock != null) {
try {
if(graceful) {
OutputStream out=client_sock.getOutputStream();
out.write(NORMAL_TERMINATION);
out.flush();
}
closeClientSocket();
}
catch(Throwable t) {
}
}
}
}
private void closeClientSocket() {
synchronized(mutex) {
Util.close(client_sock);
client_sock=null;
}
}
public void run() {
try {
synchronized(mutex) {
if(client_sock == null)
return;
in=client_sock.getInputStream();
}
int b=0;
do {
b=in.read();
}
while(b != ABNORMAL_TERMINATION && b != NORMAL_TERMINATION);
}
catch(IOException ex) {
}
finally {
Socket sock=client_sock; // PATCH: avoid race condition causing NPE
if (sock != null && !sock.isClosed())
closeClientSocket();
synchronized(clients) {
clients.remove(this);
}
}
}
}
/**
* Task that periodically broadcasts a list of suspected members to the group. Goal is not to lose
* a SUSPECT message: since these are bcast unreliably, they might get dropped. The BroadcastTask makes
* sure they are retransmitted until a view has been received which doesn't contain the suspected members
* any longer. Then the task terminates.
*/
private class BroadcastTask implements Runnable {
final Set<Address> suspected_mbrs=new HashSet<Address>();
Future<?> future;
public Set<Address> getSuspectedMembers() {
return Collections.unmodifiableSet(suspected_mbrs);
}
/** Adds a suspected member. Starts the task if not yet running */
public void addSuspectedMember(Address mbr) {
if(mbr == null) return;
if(!members.contains(mbr)) return;
synchronized(suspected_mbrs) {
if(suspected_mbrs.add(mbr))
startTask();
}
}
public void removeSuspectedMember(Address suspected_mbr) {
if(suspected_mbr == null) return;
if(log.isDebugEnabled()) log.debug("member is " + suspected_mbr);
synchronized(suspected_mbrs) {
suspected_mbrs.remove(suspected_mbr);
if(suspected_mbrs.isEmpty()) {
stopTask();
}
}
}
public void removeAll() {
synchronized(suspected_mbrs) {
suspected_mbrs.clear();
stopTask();
}
}
private void startTask() {
if(future == null || future.isDone()) {
try {
future=timer.scheduleWithFixedDelay(this, suspect_msg_interval, suspect_msg_interval, TimeUnit.MILLISECONDS);
}
catch(RejectedExecutionException e) {
if(log.isWarnEnabled())
log.warn("task " + this + " was rejected as timer thread pool is shutting down");
}
}
}
private void stopTask() {
if(future != null) {
future.cancel(false);
future=null;
}
}
/**
* Removes all elements from suspected_mbrs that are <em>not</em> in the new membership
*/
public void adjustSuspectedMembers(Vector<Address> new_mbrship) {
if(new_mbrship == null || new_mbrship.isEmpty()) return;
synchronized(suspected_mbrs) {
boolean modified=suspected_mbrs.retainAll(new_mbrship);
if(log.isTraceEnabled() && modified)
log.trace("adjusted suspected_mbrs: " + suspected_mbrs);
if(suspected_mbrs.isEmpty())
stopTask();
}
}
public void run() {
Message suspect_msg;
FdHeader hdr;
if(log.isDebugEnabled())
log.debug("broadcasting SUSPECT message (suspected_mbrs=" + suspected_mbrs + ") to group");
synchronized(suspected_mbrs) {
if(suspected_mbrs.isEmpty()) {
stopTask();
if(log.isDebugEnabled()) log.debug("task done (no suspected members)");
return;
}
hdr=new FdHeader(FdHeader.SUSPECT);
hdr.mbrs=new HashSet<Address>(suspected_mbrs);
}
suspect_msg=new Message(); // mcast SUSPECT to all members
suspect_msg.setFlag(Message.OOB);
suspect_msg.putHeader(name, hdr);
down_prot.down(new Event(Event.MSG, suspect_msg));
if(log.isDebugEnabled()) log.debug("task done");
}
}
}