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