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<table width="100%" border=0 cellspacing=0 cellpadding=1 bgcolor="#aaaaaa"><tr valign=bottom><td><a href="naming_service.cpp"><IMG SRC="/inc/img/picto-up.gif" ALT="[BACK]" BORDER="0" WIDTH="14" HEIGHT="13"></a> <b>Return to <A HREF="naming_service.cpp">naming_service.cpp</A>
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Revision <B>1.21</B>, <i>Tue Mar 26 09:45:11 2002 UTC</i> (2 months, 4 weeks ago) by <i>lecroart</i>
<BR>Branch: <b>MAIN</b>
<BR>Changes since <b>1.20: +3 -2
lines</b><PRE>
CHANGED: unified the command format
</PRE>
</td></tr></table><HR noshade><PRE>/** \file naming_service.cpp
* Naming Service (NS)
*
* $Id: naming_service.cpp,v 1.21 2002/03/26 09:45:11 lecroart Exp $
*/
/* Copyright, 2000 Nevrax Ltd.
*
* This file is part of NEVRAX NeL Network Services.
* NEVRAX NeL Network Services is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* NEVRAX NeL Network Services is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with NEVRAX NeL Network Services; see the file COPYING. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif // HAVE_CONFIG_H
#ifndef NELNS_CONFIG
#define NELNS_CONFIG ""
#endif // NELNS_CONFIG
#ifndef NELNS_LOGS
#define NELNS_LOGS ""
#endif // NELNS_LOGS
//
// Includes
//
#include "nel/misc/types_nl.h"
#include <list>
#include <string>
#include "nel/misc/debug.h"
#include "nel/misc/command.h"
#include "nel/misc/displayer.h"
#include "nel/net/service.h"
//
// Namespaces
//
using namespace std;
using namespace NLMISC;
using namespace NLNET;
//
// Structures
//
struct CServiceEntry
{
CServiceEntry (TSockId sock, CInetAddress a, string n, TServiceId s) : SockId(sock), Addr(a), Name(n), SId (s) { }
TSockId SockId; // the connection between the service and the naming service
CInetAddress Addr; // address to send to the service who wants to lookup this service
string Name; // name of the service
TServiceId SId; // id of the service
};
//
// Variables
//
list<CServiceEntry> RegisteredServices; /// List of all registred services
uint16 MinBasePort = 51000; /// Ports begin at 51000
uint16 MaxBasePort = 52000; /// (note: in this implementation there can be no more than 1000 services)
const TServiceId BaseSId = 128; /// Allocated SIds begin at 128 (except for Agent Service)
//
// Functions
//
void displayRegisteredServices (CCallbackNetBase &netbase)
{
nlinfo ("Display the %d registered services :", RegisteredServices.size());
for (list<CServiceEntry>::iterator it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
nlinfo ("> %s '%s' %s-%hu '%s'", (*it).SockId->asString().c_str(), netbase.hostAddress((*it).SockId).asString().c_str(), (*it).Name.c_str(), (uint16)(*it).SId, (*it).Addr.asString().c_str());
}
nlinfo ("End ot the list");
}
/*
* Helper procedure for cbLookupAlternate and cbUnregister.
* Note: name is used for a LOGS.
*/
list<CServiceEntry>::iterator doRemove (list<CServiceEntry>::iterator it)
{
nldebug ("Unregister the service %s-%hu '%s'", (*it).Name.c_str(), (uint16)(*it).SId, (*it).Addr.asString().c_str());
// tell to everybody that this service is unregistered
CMessage msgout ("UNB");
msgout.serial ((*it).Name);
msgout.serial ((*it).SId);
msgout.serial ((*it).Addr);
CNetManager::send ("NS", msgout, 0);
nlinfo ("Broadcast the Unregistration to everybody");
// remove the service from the registered service list
return RegisteredServices.erase (it);
}
void doUnregisterService (TServiceId sid)
{
list<CServiceEntry>::iterator it;
for (it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
if ((*it).SId == sid)
{
// found it, remove it
doRemove (it);
return;
}
}
nlwarning ("Service %hu not found", (uint16)sid);
}
void doUnregisterService (TSockId from)
{
list<CServiceEntry>::iterator it;
for (it = RegisteredServices.begin(); it != RegisteredServices.end ();)
{
if ((*it).SockId == from)
{
// it's possible that one "from" have more than one registred service, so we have to find in all the list
// found it, remove it
it = doRemove (it);
}
else
{
it++;
}
}
}
void doUnregisterService (const CInetAddress &addr)
{
list<CServiceEntry>::iterator it;
for (it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
if ((*it).Addr == addr)
{
// found it, remove it
doRemove (it);
return;
}
}
nlwarning ("Service %s not found", addr.asString().c_str());
}
/*
* Helper function for cbLookupSId and cbLookupAlternateSId. *********** OUT OF DATE ***************
* Returns NULL if service not found
*/
void doLookup (const string &sname, TServiceId sid, TSockId from, CCallbackNetBase &netbase, bool sendAll, bool useSId)
{
nlstop;
string name;
if (useSId)
name = toString (sid);
else
name = sname;
nlinfo ("Lookup for service '%s' for '%s'...", name.c_str(), netbase.hostAddress(from).asString().c_str());
displayRegisteredServices (netbase);
// Send list
vector<CInetAddress> addrs;
list<CServiceEntry>::iterator it;
for (it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
if ((useSId && (*it).SId == sid) || (!useSId && (*it).Name == name))
{
addrs.push_back ((*it).Addr);
// if it only want one, stop now to search
if (!sendAll) break;
}
}
if (addrs.size()==0)
nldebug ("Service %s is not found", name.c_str());
else if (addrs.size()==1)
nldebug ("Service %s is at %s", name.c_str(), addrs[0].asString().c_str());
else
nldebug ("%d Services %s found", addrs.size(), name.c_str());
CMessage msgout ("LK");
msgout.serialCont (addrs);
netbase.send (msgout, from);
}
/**
* Callback for service look-up. *********** OUT OF DATE ***************
*
* Message expected : LK
* - Name of service to find (string)
*
* Message emitted : LK
* - Validity time in seconds, or 0 if service not found (uint16)
* - Address of service if service found, otherwise nothing (CInetAddress)
*
* \todo Olivier: Select the best service provider, not the first one in the list
*/
static void cbLookup (CMessage& msgin, TSockId from, CCallbackNetBase &netbase)
{
nlstop;
string name;
msgin.serial (name);
// Find and return a service
doLookup (name, 0, from, netbase, false, false);
}
/**
* Callback for alternate service look-up when a service is not responding *********** OUT OF DATE ***************
*
* Message expected : LA
* - Name of service (string)
* - Address of server not responding (CInetAddress)
*
* Message emitted : no name (NS)
* - Validity time in seconds, or 0 if service not found (uint16)
* - Address of service if service found, otherwise nothing (CInetAddress)
*/
static void cbLookupAlternate (CMessage& msgin, TSockId from, CCallbackNetBase &netbase)
{
nlstop;
string name;
CInetAddress addr;
msgin.serial (name);
msgin.serial (addr);
nlinfo ("Server %s looks down, looking-up for alternative service %s", addr.asString().c_str(), name.c_str() );
// Unregister down server
doUnregisterService (addr);
// Find and return another servive
doLookup (name, 0, from, netbase, false, false);
}
/**
* Callback for service look-up for all corresponding to a name. *********** OUT OF DATE ***************
*
* Message expected : LKA
* - Name of service to find (string)
*
* Message emitted : no name (ALKA)
* - List of addresses (vector<CInetAddress>)
*/
static void cbLookupAll (CMessage& msgin, TSockId from, CCallbackNetBase &netbase)
{
nlstop;
// Receive name
string name;
msgin.serial (name);
// Find and return a service
doLookup (name, 0, from, netbase, true, false);
}
/**
* Callback for service look-up by identifier *********** OUT OF DATE ***************
*
* Message expected : LKI
* - Identifier of service to find (TServiceId)
*
* Message emitted : no name (NS)
* - Validity time in seconds, or 0 if service not found (uint16)
* - Address of service if service found, otherwise nothing (CInetAddress)
*
* \todo Olivier: Select the best service provider, not the first one in the list
*/
static void cbLookupSId (CMessage& msgin, TSockId from, CCallbackNetBase &netbase)
{
nlstop;
// Receive id
TServiceId sid;
msgin.serial (sid);
// Find and return a service
doLookup ("", sid, from, netbase, false, true);
}
/*
* Helper function for cbRegister.
* If alloc_sid is true, sid is ignored
* Returns false in case of failure of sid allocation or bad sid provided
* Note: the reply is included in this function, because it must be done before things such as syncUniTime()
*/
bool doRegister (const string &name, const CInetAddress &addr, TServiceId sid, TSockId from, CCallbackNetBase &netbase)
{
// find if the service is not already registered
uint8 ok = true;
bool needRegister = true;
for (list<CServiceEntry>::iterator it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
if ((*it).Addr.asIPString() == addr.asIPString() )
{
// we already have a service on this address, remplace it if it's the same name
if ((*it).Name == name)
{
// it's the same service, replace it
(*it).SockId = from;
sid = (*it).SId;
nlinfo ("Replace the service %s", name.c_str());
}
else
{
nlwarning ("Try to register %s to %s but the service %s already on this address. ignore it!", name.c_str(), addr.asIPString().c_str(), (*it).Name.c_str());
ok = false;
}
needRegister = false;
break;
}
}
if (needRegister)
{
if (sid == 0)
{
// we have to find a sid
sid = BaseSId;
bool found = false;
while (!found)
{
list<CServiceEntry>::iterator it;
for (it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
if ((*it).SId == sid)
{
break;
}
}
if (it == RegisteredServices.end ())
{
// ok, we have an empty sid
found = true;
}
else
{
sid++;
if (sid == 0) // round the clock
{
nlwarning ("Service identifier allocation overflow");
ok = false;
break;
}
}
}
}
else
{
// we have to check that the user provided sid is available
list<CServiceEntry>::iterator it;
for (it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
if ((*it).SId == sid)
{
nlwarning ("Sid %d already used by another service", sid);
ok = false;
break;
}
}
if (it != RegisteredServices.end ())
{
ok = true;
}
}
// if ok, register the service and send a broadcast to other people
if (ok)
{
RegisteredServices.push_back (CServiceEntry(from, addr, name, sid));
// tell to everybody that this service is registered
CMessage msgout ("RGB");
uint8 s = 1;
msgout.serial (s);
msgout.serial (const_cast<string &>(name));
msgout.serial (sid);
msgout.serial (const_cast<CInetAddress &>(addr));
CNetManager::send ("NS", msgout, 0);
nlinfo ("Broadcast the Registration to everybody");
}
}
// send the answer to the client
CMessage msgout ("RG");
msgout.serial (ok);
if (ok) msgout.serial (sid);
netbase.send (msgout, from);
netbase.flush (from);
displayRegisteredServices (netbase);
return ok!=0;
}
/**
* Callback for service registration.
*
* Message expected : RG
* - Name of service to register (string)
* - Address of service (CInetAddress)
*
* Message emitted : RG
* - Allocated service identifier (TServiceId) or 0 if failed
*/
static void cbRegister (CMessage& msgin, TSockId from, CCallbackNetBase &netbase)
{
string name;
CInetAddress addr;
TServiceId sid;
msgin.serial (name);
msgin.serial (addr);
msgin.serial (sid);
doRegister (name, addr, sid, from, netbase);
}
/**
* Callback for service unregistration.
*
* Message expected : UNI
* - Service identifier (TServiceId)
*/
static void cbUnregisterSId (CMessage& msgin, TSockId from, CCallbackNetBase &netbase)
{
TServiceId sid;
msgin.serial( sid );
doUnregisterService (sid);
displayRegisteredServices (netbase);
}
/*
* Helper function for cbQueryPort
*
* \warning QueryPort + Registration is not atomic so more than one service could ask a port before register
*/
uint16 doAllocatePort (const CInetAddress &addr)
{
static uint16 nextAvailablePort = MinBasePort;
// check if nextavailableport is free
if (nextAvailablePort >= MaxBasePort) nextAvailablePort = MinBasePort;
bool ok;
do
{
ok = true;
list<CServiceEntry>::iterator it;
for (it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
if ((*it).Addr.port () == nextAvailablePort)
{
nextAvailablePort++;
ok = false;
break;
}
}
}
while (!ok);
return nextAvailablePort++;
}
/**
* Callback for port allocation
* Note: if a service queries a port but does not register itself to the naming service, the
* port will remain allocated and unused.
*
* Message expected : QP
* - Name of service to register (string)
* - Address of service (CInetAddress) (its port can be 0)
*
* Message emitted : QP
* - Allocated port number (uint16)
*/
static void cbQueryPort (CMessage& msgin, TSockId from, CCallbackNetBase &netbase)
{
// Allocate port
uint16 port = doAllocatePort (netbase.hostAddress (from));
// Send port back
CMessage msgout ("QP");
msgout.serial (port);
netbase.send (msgout, from);
nlinfo ("A service got port %hu", port);
}
/*
* Unregisters a service if it has not been done before.
* Note: this callback is called whenever someone disconnects from the NS.
* May be there are too many calls if many clients perform many transactional lookups.
*/
static void cbDisconnect (const string &serviceName, TSockId from, void *arg)
{
doUnregisterService (from);
displayRegisteredServices (*CNetManager::getNetBase(serviceName));
}
/*
* a service is connected, send him all services infos
*/
static void cbConnect (const string &serviceName, TSockId from, void *arg)
{
CMessage msgout ("RGB");
uint8 s = RegisteredServices.size ();
msgout.serial (s);
for (list<CServiceEntry>::iterator it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
msgout.serial ((*it).Name);
msgout.serial ((*it).SId);
msgout.serial ((*it).Addr);
}
CNetManager::send ("NS", msgout, from);
nlinfo ("Sending all services available to the new client");
displayRegisteredServices (*CNetManager::getNetBase(serviceName));
}
//
// Callback array
//
TCallbackItem CallbackArray[] =
{
{ "RG", cbRegister },
{ "QP", cbQueryPort },
{ "UNI", cbUnregisterSId },
};
//
// Service
//
class CNamingService : public NLNET::IService
{
public:
void init()
{
// if a baseport is available in the config file, get it
try
{
uint16 newBasePort = ConfigFile.getVar ("BasePort").asInt ();
nlinfo ("Changing the MinBasePort number from %hu to %hu", MinBasePort, newBasePort);
sint32 delta = MaxBasePort - MinBasePort;
nlassert (delta > 0);
MinBasePort = newBasePort;
MaxBasePort = MinBasePort + uint16 (delta);
}
catch (EUnknownVar &)
{
}
// we don't try to associate message from client
CNetManager::getNetBase ("NS")->ignoreAllUnknownId (true);
// add the callback in case of disconnection
CNetManager::setConnectionCallback ("NS", cbConnect, NULL);
// add the callback in case of disconnection
CNetManager::setDisconnectionCallback ("NS", cbDisconnect, NULL);
// DEBUG
// DebugLog->addDisplayer( new CStdDisplayer() );
}
};
//
/// Naming Service
//
NLNET_OLD_SERVICE_MAIN (CNamingService, "NS", "naming_service", 50000, CallbackArray, NELNS_CONFIG, NELNS_LOGS)
//
// Commands
//
NLMISC_COMMAND (nsServices, "displays the list of all registered services", "")
{
if(args.size() != 0) return false;
log.displayNL ("Display the %d registered services :", RegisteredServices.size());
for (list<CServiceEntry>::iterator it = RegisteredServices.begin(); it != RegisteredServices.end (); it++)
{
log.displayNL ("> %s '%s' %s-%hu '%s'", (*it).SockId->asString().c_str(), CNetManager::getNetBase ("NS")->hostAddress((*it).SockId).asString().c_str(), (*it).Name.c_str(), (uint16)(*it).SId, (*it).Addr.asString().c_str());
}
log.displayNL ("End ot the list");
return true;
}
</PRE>
|
