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HandshakeServer.java
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HandshakeServer.java
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/*
* Copyright (c) 2002-2018 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.causalclustering.protocol.handshake;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.stream.Collectors;
import org.neo4j.causalclustering.messaging.Channel;
import org.neo4j.causalclustering.protocol.Protocol.ApplicationProtocol;
import org.neo4j.causalclustering.protocol.Protocol.ModifierProtocol;
import org.neo4j.stream.Streams;
import static org.neo4j.causalclustering.protocol.handshake.StatusCode.SUCCESS;
public class HandshakeServer implements ServerMessageHandler
{
private final Channel channel;
private final ApplicationProtocolRepository applicationProtocolRepository;
private final ModifierProtocolRepository modifierProtocolRepository;
private final SupportedProtocols<Integer,ApplicationProtocol> supportedApplicationProtocol;
private final ProtocolStack.Builder protocolStackBuilder = ProtocolStack.builder();
private final CompletableFuture<ProtocolStack> protocolStackFuture = new CompletableFuture<>();
private boolean magicReceived;
private boolean initialised;
HandshakeServer( ApplicationProtocolRepository applicationProtocolRepository, ModifierProtocolRepository modifierProtocolRepository, Channel channel )
{
this.channel = channel;
this.applicationProtocolRepository = applicationProtocolRepository;
this.modifierProtocolRepository = modifierProtocolRepository;
this.supportedApplicationProtocol = applicationProtocolRepository.supportedProtocol();
}
public void init()
{
channel.writeAndFlush( InitialMagicMessage.instance() );
initialised = true;
}
private void ensureMagic()
{
if ( !magicReceived )
{
decline( "No magic value received" );
throw new IllegalStateException( "Magic value not received." );
}
if ( !initialised )
{
init();
}
}
@Override
public void handle( InitialMagicMessage magicMessage )
{
if ( !magicMessage.isCorrectMagic() )
{
decline( "Incorrect magic value received" );
}
// TODO: check clusterId as well
magicReceived = true;
}
@Override
public void handle( ApplicationProtocolRequest request )
{
ensureMagic();
ApplicationProtocolResponse response;
if ( !request.protocolName().equals( supportedApplicationProtocol.identifier().canonicalName() ) )
{
response = ApplicationProtocolResponse.NO_PROTOCOL;
channel.writeAndFlush( response );
decline( String.format( "Requested protocol %s not supported", request.protocolName() ) );
}
else
{
Optional<ApplicationProtocol> selected = applicationProtocolRepository.select( request.protocolName(), supportedVersionsFor( request ) );
if ( selected.isPresent() )
{
ApplicationProtocol selectedProtocol = selected.get();
protocolStackBuilder.application( selectedProtocol );
response = new ApplicationProtocolResponse( SUCCESS, selectedProtocol.category(), selectedProtocol.implementation() );
channel.writeAndFlush( response );
}
else
{
response = ApplicationProtocolResponse.NO_PROTOCOL;
channel.writeAndFlush( response );
decline( String.format( "Do not support requested protocol %s versions %s", request.protocolName(), request.versions() ) );
}
}
}
@Override
public void handle( ModifierProtocolRequest modifierProtocolRequest )
{
ensureMagic();
ModifierProtocolResponse response;
Optional<ModifierProtocol> selected =
modifierProtocolRepository.select( modifierProtocolRequest.protocolName(), supportedVersionsFor( modifierProtocolRequest ) );
if ( selected.isPresent() )
{
ModifierProtocol modifierProtocol = selected.get();
protocolStackBuilder.modifier( modifierProtocol );
response = new ModifierProtocolResponse( SUCCESS, modifierProtocol.category(), modifierProtocol.implementation() );
}
else
{
response = ModifierProtocolResponse.failure( modifierProtocolRequest.protocolName() );
}
channel.writeAndFlush( response );
}
@Override
public void handle( SwitchOverRequest switchOverRequest )
{
ensureMagic();
ProtocolStack protocolStack = protocolStackBuilder.build();
Optional<ApplicationProtocol> switchOverProtocol =
applicationProtocolRepository.select( switchOverRequest.protocolName(), switchOverRequest.version() );
List<ModifierProtocol> switchOverModifiers = switchOverRequest.modifierProtocols()
.stream()
.map( pair -> modifierProtocolRepository.select( pair.first(), pair.other() ) )
.flatMap( Streams::ofOptional )
.collect( Collectors.toList() );
if ( !switchOverProtocol.isPresent() )
{
channel.writeAndFlush( SwitchOverResponse.FAILURE );
decline( String.format( "Cannot switch to protocol %s version %d", switchOverRequest.protocolName(), switchOverRequest.version() ) );
}
else if ( protocolStack.applicationProtocol() == null )
{
channel.writeAndFlush( SwitchOverResponse.FAILURE );
decline( String.format( "Attempted to switch to protocol %s version %d before negotiation complete",
switchOverRequest.protocolName(), switchOverRequest.version() ) );
}
else if ( !switchOverProtocol.get().equals( protocolStack.applicationProtocol() ) )
{
channel.writeAndFlush( SwitchOverResponse.FAILURE );
decline( String.format( "Switch over mismatch: requested %s version %s but negotiated %s version %s",
switchOverRequest.protocolName(), switchOverRequest.version(),
protocolStack.applicationProtocol().category(), protocolStack.applicationProtocol().implementation() ) );
}
else if ( !switchOverModifiers.equals( protocolStack.modifierProtocols() ) )
{
channel.writeAndFlush( SwitchOverResponse.FAILURE );
decline( String.format( "Switch over mismatch: requested modifiers %s but negotiated %s",
switchOverRequest.modifierProtocols(), protocolStack.modifierProtocols() ) );
}
else
{
SwitchOverResponse response = new SwitchOverResponse( SUCCESS );
channel.writeAndFlush( response );
protocolStackFuture.complete( protocolStack );
}
}
private Set<String> supportedVersionsFor( ModifierProtocolRequest request )
{
return modifierProtocolRepository.supportedProtocolFor( request.protocolName() )
.map( supported -> supported.mutuallySupportedVersionsFor( request.versions() ) )
// else protocol has been excluded in config
.orElse( Collections.emptySet() );
}
private Set<Integer> supportedVersionsFor( ApplicationProtocolRequest request )
{
return supportedApplicationProtocol.mutuallySupportedVersionsFor( request.versions() );
}
private void decline( String message )
{
channel.dispose();
protocolStackFuture.completeExceptionally( new ServerHandshakeException( message, protocolStackBuilder ) );
}
CompletableFuture<ProtocolStack> protocolStackFuture()
{
return protocolStackFuture;
}
}