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.ChannelFuture;
  12 import io.netty.channel.ChannelFutureListener;
  13 import io.netty.channel.ChannelHandlerContext;
  14 import io.netty.channel.ChannelInboundHandlerAdapter;
  15 import java.util.Collection;
  16 import javax.xml.xpath.XPathConstants;
  17 import javax.xml.xpath.XPathExpression;
  18
  19 import org.opendaylight.controller.netconf.api.NetconfClientSessionPreferences;
  20 import org.opendaylight.controller.netconf.api.NetconfDocumentedException;
  21 import org.opendaylight.controller.netconf.api.NetconfMessage;
  22 import org.opendaylight.controller.netconf.util.AbstractChannelInitializer;
  23 import org.opendaylight.controller.netconf.util.AbstractNetconfSessionNegotiator;
  24 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  25 import org.opendaylight.controller.netconf.util.messages.NetconfMessageUtil;
  26 import org.opendaylight.controller.netconf.util.messages.NetconfStartExiMessage;
  27 import org.opendaylight.controller.netconf.util.xml.XMLNetconfUtil;
  28 import org.opendaylight.controller.netconf.util.xml.XmlNetconfConstants;
  29 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  30 import org.slf4j.Logger;
  31 import org.slf4j.LoggerFactory;
  32 import org.w3c.dom.Document;
  33 import org.w3c.dom.Node;
  34 import org.w3c.dom.NodeList;
  35
  36 import io.netty.channel.Channel;
  37 import io.netty.util.Timer;
  38 import io.netty.util.concurrent.Promise;
  39
  40 public class NetconfClientSessionNegotiator extends
  41         AbstractNetconfSessionNegotiator<NetconfClientSessionPreferences, NetconfClientSession, NetconfClientSessionListener>
  42 {
  43     private static final Logger logger = 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(NetconfClientSessionPreferences sessionPreferences,
  51                                              Promise<NetconfClientSession> promise,
  52                                              Channel channel,
  53                                              Timer timer,
  54                                              NetconfClientSessionListener sessionListener,
  55                                              long connectionTimeoutMillis) {
  56         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  57     }
  58
  59     @Override
  60     protected void handleMessage(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             logger.debug("Netconf session {} should use exi.", session);
  68             NetconfStartExiMessage startExiMessage = (NetconfStartExiMessage) sessionPreferences.getStartExiMessage();
  69             tryToInitiateExi(session, startExiMessage);
  70         // Exi is not supported, release session immediately
  71         } else {
  72             logger.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                     logger.warn("Failed to send start-exi message {} on session {}", startExiMessage, this, f.cause());
  92                     channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
  93                 } else {
  94                     logger.trace("Start-exi message {} sent to socket on session {}", startExiMessage, this);
  95                 }
  96             }
  97         });
  98     }
  99
 100     private boolean shouldUseExi(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(Document doc) {
 116         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 117         String textContent = sessionIdNode.getTextContent();
 118         if (textContent == null || textContent.equals("")) {
 119             throw new IllegalStateException("Session id not received from server");
 120         }
 121
 122         return Long.valueOf(textContent);
 123     }
 124
 125     @Override
 126     protected NetconfClientSession getSession(NetconfClientSessionListener sessionListener, Channel channel,
 127             NetconfHelloMessage message) throws NetconfDocumentedException {
 128         long sessionId = extractSessionId(message.getDocument());
 129         Collection<String> capabilities = NetconfMessageUtil.extractCapabilitiesFromHello(message.getDocument());
 130         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 131     }
 132
 133     /**
 134      * Handler to process response for start-exi message
 135      */
 136     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 137         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 138
 139         private final NetconfClientSession session;
 140         private NetconfStartExiMessage startExiMessage;
 141
 142         ExiConfirmationInboundHandler(NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
 143             this.session = session;
 144             this.startExiMessage = startExiMessage;
 145         }
 146
 147         @Override
 148         public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
 149             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 150
 151             NetconfMessage netconfMessage = (NetconfMessage) msg;
 152
 153             // Ok response to start-exi, try to add exi handlers
 154             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 155                 logger.trace("Positive response on start-exi call received on session {}", session);
 156                 try {
 157                     session.startExiCommunication(startExiMessage);
 158                 } catch (RuntimeException e) {
 159                     // Unable to add exi, continue without exi
 160                     logger.warn("Unable to start exi communication, Communication will continue without exi on session {}", session, e);
 161                 }
 162
 163                 // Error response
 164             } else if(NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 165                 logger.warn(
 166                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 167                         XmlUtil.toString(netconfMessage.getDocument()), session);
 168
 169                 // Unexpected response to start-exi, throwing message away, continue without exi
 170             } else {
 171                 logger.warn(
 172                         "Unexpected response to start-exi message, should be ok, was {}, " +
 173                                 "Communication will continue without exi and response message will be thrown away on session {}",
 174                         XmlUtil.toString(netconfMessage.getDocument()), session);
 175             }
 176
 177             negotiationSuccessful(session);
 178         }
 179     }
 180
 181 }