bgp/rib-impl/src/main/java/org/opendaylight/protocol/bgp/rib/impl/protocol/BGPReconnectPromise.java

   1 /*
   2  * Copyright (c) 2015 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.protocol.bgp.rib.impl.protocol;
   9
  10 import com.google.common.base.Preconditions;
  11 import io.netty.bootstrap.Bootstrap;
  12 import io.netty.channel.ChannelHandler;
  13 import io.netty.channel.ChannelHandlerContext;
  14 import io.netty.channel.ChannelInboundHandlerAdapter;
  15 import io.netty.channel.socket.SocketChannel;
  16 import io.netty.util.concurrent.DefaultPromise;
  17 import io.netty.util.concurrent.EventExecutor;
  18 import io.netty.util.concurrent.Future;
  19 import io.netty.util.concurrent.GenericFutureListener;
  20 import io.netty.util.concurrent.Promise;
  21 import java.net.InetSocketAddress;
  22 import org.opendaylight.protocol.bgp.rib.impl.BGPDispatcherImpl;
  23 import org.opendaylight.protocol.bgp.rib.impl.BGPSessionImpl;
  24 import org.opendaylight.protocol.framework.ReconnectStrategy;
  25 import org.opendaylight.protocol.framework.ReconnectStrategyFactory;
  26 import org.slf4j.Logger;
  27 import org.slf4j.LoggerFactory;
  28
  29 public class BGPReconnectPromise extends DefaultPromise<Void> {
  30     private static final Logger LOG = LoggerFactory.getLogger(BGPReconnectPromise.class);
  31
  32     private final InetSocketAddress address;
  33     private final ReconnectStrategyFactory strategyFactory;
  34     private final Bootstrap b;
  35     private final BGPDispatcherImpl.ChannelPipelineInitializer initializer;
  36     private final EventExecutor executor;
  37     private Future<BGPSessionImpl> pending;
  38
  39     public BGPReconnectPromise(final EventExecutor executor, final InetSocketAddress address,
  40                                final ReconnectStrategyFactory connectStrategyFactory, final Bootstrap b,
  41                                final BGPDispatcherImpl.ChannelPipelineInitializer initializer) {
  42         super(executor);
  43         this.executor = executor;
  44         this.b = b;
  45         this.initializer = Preconditions.checkNotNull(initializer);
  46         this.address = Preconditions.checkNotNull(address);
  47         this.strategyFactory = Preconditions.checkNotNull(connectStrategyFactory);
  48     }
  49
  50     public synchronized void connect() {
  51         final ReconnectStrategy cs = this.strategyFactory.createReconnectStrategy();
  52
  53         // Set up a client with pre-configured bootstrap, but add a closed channel handler into the pipeline to support reconnect attempts
  54         pending = createClient(this.address, cs, b, new BGPDispatcherImpl.ChannelPipelineInitializer() {
  55             @Override
  56             public void initializeChannel(final SocketChannel channel, final Promise<BGPSessionImpl> promise) {
  57                 initializer.initializeChannel(channel, promise);
  58                 // add closed channel handler
  59                 // This handler has to be added as last channel handler and the channel inactive event has to be caught by it
  60                 // Handlers in front of it can react to channelInactive event, but have to forward the event or the reconnect will not work
  61                 // This handler is last so all handlers in front of it can handle channel inactive (to e.g. resource cleanup) before a new connection is started
  62                 channel.pipeline().addLast(new ClosedChannelHandler(BGPReconnectPromise.this));
  63             }
  64         });
  65
  66         pending.addListener(new GenericFutureListener<Future<Object>>() {
  67             @Override
  68             public void operationComplete(Future<Object> future) throws Exception {
  69                 if (!future.isSuccess()) {
  70                     BGPReconnectPromise.this.setFailure(future.cause());
  71                 }
  72             }
  73         });
  74     }
  75
  76     public Future<BGPSessionImpl> createClient(final InetSocketAddress address, final ReconnectStrategy strategy, final Bootstrap bootstrap,
  77                                                final BGPDispatcherImpl.ChannelPipelineInitializer initializer) {
  78         final BGPProtocolSessionPromise p = new BGPProtocolSessionPromise(this.executor, address, strategy, bootstrap);
  79         final ChannelHandler chInit = BGPDispatcherImpl.BGPChannel.createChannelInitializer(initializer, p);
  80         bootstrap.handler(chInit);
  81         p.connect();
  82         LOG.debug("Client created.");
  83         return p;
  84     }
  85
  86     /**
  87      * @return true if initial connection was established successfully, false if initial connection failed due to e.g. Connection refused, Negotiation failed
  88      */
  89     private boolean isInitialConnectFinished() {
  90         Preconditions.checkNotNull(pending);
  91         return pending.isDone() && pending.isSuccess();
  92     }
  93
  94     @Override
  95     public synchronized boolean cancel(final boolean mayInterruptIfRunning) {
  96         if (super.cancel(mayInterruptIfRunning)) {
  97             Preconditions.checkNotNull(pending);
  98             this.pending.cancel(mayInterruptIfRunning);
  99             return true;
 100         }
 101
 102         return false;
 103     }
 104
 105     /**
 106      * Channel handler that responds to channelInactive event and reconnects the session.
 107      * Only if the promise was not canceled.
 108      */
 109     private static final class ClosedChannelHandler extends ChannelInboundHandlerAdapter {
 110         private final BGPReconnectPromise promise;
 111
 112         public ClosedChannelHandler(final BGPReconnectPromise promise) {
 113             this.promise = promise;
 114         }
 115
 116         @Override
 117         public void channelInactive(final ChannelHandlerContext ctx) throws Exception {
 118             // This is the ultimate channel inactive handler, not forwarding
 119             if (promise.isCancelled()) {
 120                 return;
 121             }
 122
 123             if (!promise.isInitialConnectFinished()) {
 124                 LOG.debug("Connection to {} was dropped during negotiation, reattempting", promise.address);
 125             }
 126
 127             LOG.debug("Reconnecting after connection to {} was dropped", promise.address);
 128             promise.connect();
 129         }
 130     }
 131 }