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
  14 import io.netty.channel.Channel;
  15 import io.netty.channel.ChannelFuture;
  16 import io.netty.channel.ChannelFutureListener;
  17 import io.netty.channel.ChannelHandlerContext;
  18 import io.netty.channel.ChannelInboundHandlerAdapter;
  19 import io.netty.util.Timer;
  20 import io.netty.util.concurrent.Promise;
  21
  22 import java.util.Collection;
  23
  24 import javax.xml.xpath.XPathConstants;
  25 import javax.xml.xpath.XPathExpression;
  26
  27 import org.opendaylight.controller.netconf.api.NetconfClientSessionPreferences;
  28 import org.opendaylight.controller.netconf.api.NetconfDocumentedException;
  29 import org.opendaylight.controller.netconf.api.NetconfMessage;
  30 import org.opendaylight.controller.netconf.api.xml.XmlNetconfConstants;
  31 import org.opendaylight.controller.netconf.nettyutil.AbstractChannelInitializer;
  32 import org.opendaylight.controller.netconf.nettyutil.AbstractNetconfSessionNegotiator;
  33 import org.opendaylight.controller.netconf.nettyutil.handler.exi.NetconfStartExiMessage;
  34 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  35 import org.opendaylight.controller.netconf.util.messages.NetconfMessageUtil;
  36 import org.opendaylight.controller.netconf.util.xml.XMLNetconfUtil;
  37 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  38 import org.slf4j.Logger;
  39 import org.slf4j.LoggerFactory;
  40 import org.w3c.dom.Document;
  41 import org.w3c.dom.Node;
  42 import org.w3c.dom.NodeList;
  43
  44 public class NetconfClientSessionNegotiator extends
  45         AbstractNetconfSessionNegotiator<NetconfClientSessionPreferences, NetconfClientSession, NetconfClientSessionListener>
  46 {
  47     private static final Logger logger = LoggerFactory.getLogger(NetconfClientSessionNegotiator.class);
  48
  49     private static final XPathExpression sessionIdXPath = XMLNetconfUtil
  50             .compileXPath("/netconf:hello/netconf:session-id");
  51
  52     private static final String EXI_1_0_CAPABILITY_MARKER = "exi:1.0";
  53
  54     protected NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  55                                              final Promise<NetconfClientSession> promise,
  56                                              final Channel channel,
  57                                              final Timer timer,
  58                                              final NetconfClientSessionListener sessionListener,
  59                                              final long connectionTimeoutMillis) {
  60         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  61     }
  62
  63     @Override
  64     protected void handleMessage(final NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
  65         final NetconfClientSession session = getSessionForHelloMessage(netconfMessage);
  66         replaceHelloMessageInboundHandler(session);
  67
  68         // If exi should be used, try to initiate exi communication
  69         // Call negotiationSuccessFul after exi negotiation is finished successfully or not
  70         if (shouldUseExi(netconfMessage)) {
  71             logger.debug("Netconf session {} should use exi.", session);
  72             NetconfStartExiMessage startExiMessage = (NetconfStartExiMessage) sessionPreferences.getStartExiMessage();
  73             tryToInitiateExi(session, startExiMessage);
  74         } else {
  75             // Exi is not supported, release session immediately
  76             logger.debug("Netconf session {} isn't capable of using exi.", session);
  77             negotiationSuccessful(session);
  78         }
  79     }
  80
  81     /**
  82      * Initiates exi communication by sending start-exi message and waiting for positive/negative response.
  83      *
  84      * @param startExiMessage
  85      */
  86     void tryToInitiateExi(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
  87         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_DECODER,
  88                 ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER,
  89                 new ExiConfirmationInboundHandler(session, startExiMessage));
  90
  91         session.sendMessage(startExiMessage).addListener(new ChannelFutureListener() {
  92             @Override
  93             public void operationComplete(final ChannelFuture f) {
  94                 if (!f.isSuccess()) {
  95                     logger.warn("Failed to send start-exi message {} on session {}", startExiMessage, this, f.cause());
  96                     channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
  97                 } else {
  98                     logger.trace("Start-exi message {} sent to socket on session {}", startExiMessage, this);
  99                 }
 100             }
 101         });
 102     }
 103
 104     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 105         return containsExi10Capability(helloMsg.getDocument())
 106                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 107     }
 108
 109     private boolean containsExi10Capability(final Document doc) {
 110         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 111         for (int i = 0; i < nList.getLength(); i++) {
 112             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 113                 return true;
 114             }
 115         }
 116         return false;
 117     }
 118
 119     private long extractSessionId(final Document doc) {
 120         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 121         Preconditions.checkState(sessionIdNode != null, "");
 122         String textContent = sessionIdNode.getTextContent();
 123         if (textContent == null || textContent.equals("")) {
 124             throw new IllegalStateException("Session id not received from server");
 125         }
 126
 127         return Long.valueOf(textContent);
 128     }
 129
 130     @Override
 131     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 132             final NetconfHelloMessage message) throws NetconfDocumentedException {
 133         long sessionId = extractSessionId(message.getDocument());
 134
 135         // Copy here is important: it disconnects the strings from the document
 136         Collection<String> capabilities = ImmutableList.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message.getDocument()));
 137
 138         // FIXME: scalability: we could instantiate a cache to share the same collections
 139         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 140     }
 141
 142     /**
 143      * Handler to process response for start-exi message
 144      */
 145     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 146         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 147
 148         private final NetconfClientSession session;
 149         private final NetconfStartExiMessage startExiMessage;
 150
 151         ExiConfirmationInboundHandler(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
 152             this.session = session;
 153             this.startExiMessage = startExiMessage;
 154         }
 155
 156         @Override
 157         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 158             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 159
 160             NetconfMessage netconfMessage = (NetconfMessage) msg;
 161
 162             // Ok response to start-exi, try to add exi handlers
 163             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 164                 logger.trace("Positive response on start-exi call received on session {}", session);
 165                 try {
 166                     session.startExiCommunication(startExiMessage);
 167                 } catch (RuntimeException e) {
 168                     // Unable to add exi, continue without exi
 169                     logger.warn("Unable to start exi communication, Communication will continue without exi on session {}", session, e);
 170                 }
 171
 172                 // Error response
 173             } else if(NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 174                 logger.warn(
 175                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 176                         XmlUtil.toString(netconfMessage.getDocument()), session);
 177
 178                 // Unexpected response to start-exi, throwing message away, continue without exi
 179             } else {
 180                 logger.warn(
 181                         "Unexpected response to start-exi message, should be ok, was {}, " +
 182                                 "Communication will continue without exi and response message will be thrown away on session {}",
 183                         XmlUtil.toString(netconfMessage.getDocument()), session);
 184             }
 185
 186             negotiationSuccessful(session);
 187         }
 188     }
 189
 190 }