opendaylight/netconf/netconf-client/src/main/java/org/opendaylight/controller/netconf/client/NetconfClientSessionNegotiator.java

   1 /*
   2  * Copyright (c) 2013 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
   9 package org.opendaylight.controller.netconf.client;
  10
  11 import com.google.common.base.Preconditions;
  12 import com.google.common.collect.ImmutableList;
  13 import io.netty.channel.Channel;
  14 import io.netty.channel.ChannelFuture;
  15 import io.netty.channel.ChannelFutureListener;
  16 import io.netty.channel.ChannelHandlerContext;
  17 import io.netty.channel.ChannelInboundHandlerAdapter;
  18 import io.netty.util.Timer;
  19 import io.netty.util.concurrent.Promise;
  20 import java.util.Collection;
  21 import javax.xml.xpath.XPathConstants;
  22 import javax.xml.xpath.XPathExpression;
  23 import org.opendaylight.controller.netconf.api.NetconfClientSessionPreferences;
  24 import org.opendaylight.controller.netconf.api.NetconfDocumentedException;
  25 import org.opendaylight.controller.netconf.api.NetconfMessage;
  26 import org.opendaylight.controller.netconf.api.xml.XmlNetconfConstants;
  27 import org.opendaylight.controller.netconf.nettyutil.AbstractChannelInitializer;
  28 import org.opendaylight.controller.netconf.nettyutil.AbstractNetconfSessionNegotiator;
  29 import org.opendaylight.controller.netconf.nettyutil.handler.exi.NetconfStartExiMessage;
  30 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  31 import org.opendaylight.controller.netconf.util.messages.NetconfMessageUtil;
  32 import org.opendaylight.controller.netconf.util.xml.XMLNetconfUtil;
  33 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36 import org.w3c.dom.Document;
  37 import org.w3c.dom.Node;
  38 import org.w3c.dom.NodeList;
  39
  40 public class NetconfClientSessionNegotiator extends
  41         AbstractNetconfSessionNegotiator<NetconfClientSessionPreferences, NetconfClientSession, NetconfClientSessionListener>
  42 {
  43     private static final Logger LOG = LoggerFactory.getLogger(NetconfClientSessionNegotiator.class);
  44
  45     private static final XPathExpression sessionIdXPath = XMLNetconfUtil
  46             .compileXPath("/netconf:hello/netconf:session-id");
  47
  48     private static final String EXI_1_0_CAPABILITY_MARKER = "exi:1.0";
  49
  50     protected NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  51                                              final Promise<NetconfClientSession> promise,
  52                                              final Channel channel,
  53                                              final Timer timer,
  54                                              final NetconfClientSessionListener sessionListener,
  55                                              final long connectionTimeoutMillis) {
  56         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  57     }
  58
  59     @Override
  60     protected void handleMessage(final NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
  61         final NetconfClientSession session = getSessionForHelloMessage(netconfMessage);
  62         replaceHelloMessageInboundHandler(session);
  63
  64         // If exi should be used, try to initiate exi communication
  65         // Call negotiationSuccessFul after exi negotiation is finished successfully or not
  66         if (shouldUseExi(netconfMessage)) {
  67             LOG.debug("Netconf session {} should use exi.", session);
  68             NetconfStartExiMessage startExiMessage = (NetconfStartExiMessage) sessionPreferences.getStartExiMessage();
  69             tryToInitiateExi(session, startExiMessage);
  70         } else {
  71             // Exi is not supported, release session immediately
  72             LOG.debug("Netconf session {} isn't capable of using exi.", session);
  73             negotiationSuccessful(session);
  74         }
  75     }
  76
  77     /**
  78      * Initiates exi communication by sending start-exi message and waiting for positive/negative response.
  79      *
  80      * @param startExiMessage
  81      */
  82     void tryToInitiateExi(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
  83         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_DECODER,
  84                 ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER,
  85                 new ExiConfirmationInboundHandler(session, startExiMessage));
  86
  87         session.sendMessage(startExiMessage).addListener(new ChannelFutureListener() {
  88             @Override
  89             public void operationComplete(final ChannelFuture f) {
  90                 if (!f.isSuccess()) {
  91                     LOG.warn("Failed to send start-exi message {} on session {}", startExiMessage, this, f.cause());
  92                     channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
  93                 } else {
  94                     LOG.trace("Start-exi message {} sent to socket on session {}", startExiMessage, this);
  95                 }
  96             }
  97         });
  98     }
  99
 100     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 101         return containsExi10Capability(helloMsg.getDocument())
 102                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 103     }
 104
 105     private boolean containsExi10Capability(final Document doc) {
 106         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 107         for (int i = 0; i < nList.getLength(); i++) {
 108             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 109                 return true;
 110             }
 111         }
 112         return false;
 113     }
 114
 115     private long extractSessionId(final Document doc) {
 116         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 117         Preconditions.checkState(sessionIdNode != null, "");
 118         String textContent = sessionIdNode.getTextContent();
 119         if (textContent == null || textContent.equals("")) {
 120             throw new IllegalStateException("Session id not received from server");
 121         }
 122
 123         return Long.valueOf(textContent);
 124     }
 125
 126     @Override
 127     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 128             final NetconfHelloMessage message) throws NetconfDocumentedException {
 129         long sessionId = extractSessionId(message.getDocument());
 130
 131         // Copy here is important: it disconnects the strings from the document
 132         Collection<String> capabilities = ImmutableList.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message.getDocument()));
 133
 134         // FIXME: scalability: we could instantiate a cache to share the same collections
 135         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 136     }
 137
 138     /**
 139      * Handler to process response for start-exi message
 140      */
 141     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 142         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 143
 144         private final NetconfClientSession session;
 145         private final NetconfStartExiMessage startExiMessage;
 146
 147         ExiConfirmationInboundHandler(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
 148             this.session = session;
 149             this.startExiMessage = startExiMessage;
 150         }
 151
 152         @Override
 153         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 154             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 155
 156             NetconfMessage netconfMessage = (NetconfMessage) msg;
 157
 158             // Ok response to start-exi, try to add exi handlers
 159             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 160                 LOG.trace("Positive response on start-exi call received on session {}", session);
 161                 try {
 162                     session.startExiCommunication(startExiMessage);
 163                 } catch (RuntimeException e) {
 164                     // Unable to add exi, continue without exi
 165                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session {}", session, e);
 166                 }
 167
 168                 // Error response
 169             } else if(NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 170                 LOG.warn(
 171                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 172                         XmlUtil.toString(netconfMessage.getDocument()), session);
 173
 174                 // Unexpected response to start-exi, throwing message away, continue without exi
 175             } else {
 176                 LOG.warn(
 177                         "Unexpected response to start-exi message, should be ok, was {}, ",XmlUtil.toString(netconfMessage.getDocument()),
 178                         "Communication will continue without exi and response message will be thrown away on session {}",
 179                          session);
 180             }
 181
 182             negotiationSuccessful(session);
 183         }
 184     }
 185
 186 }