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 static java.util.Objects.requireNonNull;
  11
  12 import io.netty.bootstrap.Bootstrap;
  13 import io.netty.channel.ChannelHandler;
  14 import io.netty.channel.ChannelHandlerContext;
  15 import io.netty.channel.ChannelInboundHandlerAdapter;
  16 import io.netty.channel.ChannelInitializer;
  17 import io.netty.channel.socket.SocketChannel;
  18 import io.netty.util.concurrent.DefaultPromise;
  19 import io.netty.util.concurrent.EventExecutor;
  20 import java.net.InetSocketAddress;
  21 import javax.annotation.Nonnull;
  22 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPPeerRegistry;
  23 import org.opendaylight.protocol.bgp.rib.impl.spi.ChannelPipelineInitializer;
  24 import org.opendaylight.protocol.bgp.rib.spi.BGPSession;
  25 import org.slf4j.Logger;
  26 import org.slf4j.LoggerFactory;
  27
  28 public class BGPReconnectPromise<S extends BGPSession> extends DefaultPromise<Void> {
  29     private static final Logger LOG = LoggerFactory.getLogger(BGPReconnectPromise.class);
  30
  31     private final InetSocketAddress address;
  32     private final int retryTimer;
  33     private final Bootstrap bootstrap;
  34     private final BGPPeerRegistry peerRegistry;
  35     private final ChannelPipelineInitializer<S> initializer;
  36     private BGPProtocolSessionPromise<S> pending;
  37
  38     public BGPReconnectPromise(@Nonnull final EventExecutor executor, @Nonnull final InetSocketAddress address,
  39         final int retryTimer, @Nonnull final Bootstrap bootstrap, @Nonnull final BGPPeerRegistry peerRegistry,
  40         @Nonnull final ChannelPipelineInitializer<S> initializer) {
  41         super(executor);
  42         this.bootstrap = bootstrap;
  43         this.initializer = requireNonNull(initializer);
  44         this.address = requireNonNull(address);
  45         this.retryTimer = retryTimer;
  46         this.peerRegistry = requireNonNull(peerRegistry);
  47     }
  48
  49     public synchronized void connect() {
  50         if (this.pending != null) {
  51             this.pending.cancel(true);
  52         }
  53
  54         // Set up a client with pre-configured bootstrap, but add a closed channel handler
  55         // into the pipeline to support reconnect attempts
  56         this.pending = connectSessionPromise(this.address, this.retryTimer, this.bootstrap, this.peerRegistry,
  57                 (channel, promise) -> {
  58                     this.initializer.initializeChannel(channel, promise);
  59                     // add closed channel handler
  60                     // This handler has to be added as last channel handler and the channel inactive event has to be
  61                     // caught by it
  62                     // Handlers in front of it can react to channelInactive event, but have to forward the event or
  63                     // the reconnect will not work. This handler is last so all handlers in front of it can handle
  64                     // channel inactive (to e.g. resource cleanup) before a new connection is started
  65                     channel.pipeline().addLast(new ClosedChannelHandler(this));
  66                 });
  67
  68         this.pending.addListener(future -> {
  69             if (!future.isSuccess() && !this.isDone()) {
  70                 this.setFailure(future.cause());
  71             }
  72         });
  73     }
  74
  75     private BGPProtocolSessionPromise<S> connectSessionPromise(final InetSocketAddress address, final int retryTimer,
  76             final Bootstrap bootstrap, final BGPPeerRegistry peerRegistry,
  77             final ChannelPipelineInitializer<S> initializer) {
  78         final BGPProtocolSessionPromise<S> sessionPromise = new BGPProtocolSessionPromise<>(address, retryTimer,
  79                 bootstrap, peerRegistry);
  80         final ChannelHandler chInit = new ChannelInitializer<SocketChannel>() {
  81             @Override
  82             protected void initChannel(final SocketChannel channel) {
  83                 initializer.initializeChannel(channel, sessionPromise);
  84             }
  85         };
  86
  87         bootstrap.handler(chInit);
  88         sessionPromise.connect();
  89         LOG.debug("Client created.");
  90         return sessionPromise;
  91     }
  92
  93     /**
  94      * @return true if initial connection was established successfully, false if initial connection failed due
  95      *         to e.g. Connection refused, Negotiation failed
  96      */
  97     private  synchronized boolean isInitialConnectFinished() {
  98         requireNonNull(this.pending);
  99         return this.pending.isDone() && this.pending.isSuccess();
 100     }
 101
 102     private synchronized void reconnect() {
 103         requireNonNull(this.pending);
 104         this.pending.reconnect();
 105     }
 106
 107     @Override
 108     public synchronized boolean cancel(final boolean mayInterruptIfRunning) {
 109         if (super.cancel(mayInterruptIfRunning)) {
 110             requireNonNull(this.pending);
 111             this.pending.cancel(mayInterruptIfRunning);
 112             return true;
 113         }
 114         return false;
 115     }
 116
 117     /**
 118      * Channel handler that responds to channelInactive event and reconnects the session.
 119      * Only if the promise was not canceled.
 120      */
 121     private static final class ClosedChannelHandler extends ChannelInboundHandlerAdapter {
 122         private final BGPReconnectPromise<?> promise;
 123
 124         ClosedChannelHandler(final BGPReconnectPromise<?> promise) {
 125             this.promise = promise;
 126         }
 127
 128         @Override
 129         public void channelInactive(final ChannelHandlerContext ctx) throws Exception {
 130             // This is the ultimate channel inactive handler, not forwarding
 131             if (this.promise.isCancelled()) {
 132                 return;
 133             }
 134
 135             if (!this.promise.isInitialConnectFinished()) {
 136                 LOG.debug("Connection to {} was dropped during negotiation, reattempting", this.promise.address);
 137                 this.promise.reconnect();
 138                 return;
 139             }
 140
 141             LOG.debug("Reconnecting after connection to {} was dropped", this.promise.address);
 142             this.promise.connect();
 143         }
 144     }
 145 }