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.Strings;
  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 XPathExpression sessionIdXPathNoNamespace = XMLNetconfUtil
  49             .compileXPath("/hello/session-id");
  50
  51     private static final String EXI_1_0_CAPABILITY_MARKER = "exi:1.0";
  52
  53     protected NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  54                                              final Promise<NetconfClientSession> promise,
  55                                              final Channel channel,
  56                                              final Timer timer,
  57                                              final NetconfClientSessionListener sessionListener,
  58                                              final long connectionTimeoutMillis) {
  59         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  60     }
  61
  62     @Override
  63     protected void handleMessage(final NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
  64         final NetconfClientSession session = getSessionForHelloMessage(netconfMessage);
  65         replaceHelloMessageInboundHandler(session);
  66
  67         // If exi should be used, try to initiate exi communication
  68         // Call negotiationSuccessFul after exi negotiation is finished successfully or not
  69         if (shouldUseExi(netconfMessage)) {
  70             LOG.debug("Netconf session {} should use exi.", session);
  71             NetconfStartExiMessage startExiMessage = (NetconfStartExiMessage) sessionPreferences.getStartExiMessage();
  72             tryToInitiateExi(session, startExiMessage);
  73         } else {
  74             // Exi is not supported, release session immediately
  75             LOG.debug("Netconf session {} isn't capable of using exi.", session);
  76             negotiationSuccessful(session);
  77         }
  78     }
  79
  80     /**
  81      * Initiates exi communication by sending start-exi message and waiting for positive/negative response.
  82      *
  83      * @param startExiMessage
  84      */
  85     void tryToInitiateExi(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
  86         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_DECODER,
  87                 ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER,
  88                 new ExiConfirmationInboundHandler(session, startExiMessage));
  89
  90         session.sendMessage(startExiMessage).addListener(new ChannelFutureListener() {
  91             @Override
  92             public void operationComplete(final ChannelFuture f) {
  93                 if (!f.isSuccess()) {
  94                     LOG.warn("Failed to send start-exi message {} on session {}", startExiMessage, this, f.cause());
  95                     channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
  96                 } else {
  97                     LOG.trace("Start-exi message {} sent to socket on session {}", startExiMessage, this);
  98                 }
  99             }
 100         });
 101     }
 102
 103     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 104         return containsExi10Capability(helloMsg.getDocument())
 105                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 106     }
 107
 108     private boolean containsExi10Capability(final Document doc) {
 109         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 110         for (int i = 0; i < nList.getLength(); i++) {
 111             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 112                 return true;
 113             }
 114         }
 115         return false;
 116     }
 117
 118     private long extractSessionId(final Document doc) {
 119         String textContent = getSessionIdWithXPath(doc, sessionIdXPath);
 120         if (Strings.isNullOrEmpty(textContent)) {
 121             textContent = getSessionIdWithXPath(doc, sessionIdXPathNoNamespace);
 122             if (Strings.isNullOrEmpty(textContent)) {
 123                 throw new IllegalStateException("Session id not received from server, hello message: " + XmlUtil.toString(doc));
 124             }
 125         }
 126
 127         return Long.valueOf(textContent);
 128     }
 129
 130     private String getSessionIdWithXPath(final Document doc, final XPathExpression sessionIdXPath) {
 131         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 132         return sessionIdNode != null ? sessionIdNode.getTextContent() : null;
 133     }
 134
 135     @Override
 136     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 137             final NetconfHelloMessage message) throws NetconfDocumentedException {
 138         long sessionId = extractSessionId(message.getDocument());
 139
 140         // Copy here is important: it disconnects the strings from the document
 141         Collection<String> capabilities = ImmutableList.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message.getDocument()));
 142
 143         // FIXME: scalability: we could instantiate a cache to share the same collections
 144         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 145     }
 146
 147     /**
 148      * Handler to process response for start-exi message
 149      */
 150     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 151         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 152
 153         private final NetconfClientSession session;
 154         private final NetconfStartExiMessage startExiMessage;
 155
 156         ExiConfirmationInboundHandler(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
 157             this.session = session;
 158             this.startExiMessage = startExiMessage;
 159         }
 160
 161         @Override
 162         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 163             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 164
 165             NetconfMessage netconfMessage = (NetconfMessage) msg;
 166
 167             // Ok response to start-exi, try to add exi handlers
 168             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 169                 LOG.trace("Positive response on start-exi call received on session {}", session);
 170                 try {
 171                     session.startExiCommunication(startExiMessage);
 172                 } catch (RuntimeException e) {
 173                     // Unable to add exi, continue without exi
 174                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session {}", session, e);
 175                 }
 176
 177                 // Error response
 178             } else if(NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 179                 LOG.warn(
 180                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 181                         netconfMessage, session);
 182
 183                 // Unexpected response to start-exi, throwing message away, continue without exi
 184             } else {
 185                 LOG.warn("Unexpected response to start-exi message, should be ok, was {}, " +
 186                          "Communication will continue without exi and response message will be thrown away on session {}",
 187                          netconfMessage, session);
 188             }
 189
 190             negotiationSuccessful(session);
 191         }
 192     }
 193
 194 }