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