netconf/netconf-client/src/main/java/org/opendaylight/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.netconf.client;
  10
  11 import com.google.common.base.Strings;
  12 import com.google.common.collect.ImmutableSet;
  13 import com.google.common.collect.Interner;
  14 import com.google.common.collect.Interners;
  15 import io.netty.channel.Channel;
  16 import io.netty.channel.ChannelFuture;
  17 import io.netty.channel.ChannelFutureListener;
  18 import io.netty.channel.ChannelHandlerContext;
  19 import io.netty.channel.ChannelInboundHandlerAdapter;
  20 import io.netty.util.Timer;
  21 import io.netty.util.concurrent.Promise;
  22 import java.util.Set;
  23 import javax.xml.xpath.XPathConstants;
  24 import javax.xml.xpath.XPathExpression;
  25 import org.opendaylight.controller.config.util.xml.XmlUtil;
  26 import org.opendaylight.netconf.api.NetconfClientSessionPreferences;
  27 import org.opendaylight.netconf.api.NetconfDocumentedException;
  28 import org.opendaylight.netconf.api.NetconfMessage;
  29 import org.opendaylight.netconf.api.messages.NetconfHelloMessage;
  30 import org.opendaylight.netconf.api.xml.XmlNetconfConstants;
  31 import org.opendaylight.netconf.nettyutil.AbstractChannelInitializer;
  32 import org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator;
  33 import org.opendaylight.netconf.nettyutil.handler.exi.NetconfStartExiMessage;
  34 import org.opendaylight.netconf.util.messages.NetconfMessageUtil;
  35 import org.opendaylight.netconf.util.xml.XMLNetconfUtil;
  36 import org.slf4j.Logger;
  37 import org.slf4j.LoggerFactory;
  38 import org.w3c.dom.Document;
  39 import org.w3c.dom.Node;
  40 import org.w3c.dom.NodeList;
  41
  42 public class NetconfClientSessionNegotiator extends
  43         AbstractNetconfSessionNegotiator<NetconfClientSessionPreferences, NetconfClientSession, NetconfClientSessionListener>
  44 {
  45     private static final Logger LOG = LoggerFactory.getLogger(NetconfClientSessionNegotiator.class);
  46
  47     private static final XPathExpression sessionIdXPath = XMLNetconfUtil
  48             .compileXPath("/netconf:hello/netconf:session-id");
  49
  50     private static final XPathExpression sessionIdXPathNoNamespace = XMLNetconfUtil
  51             .compileXPath("/hello/session-id");
  52
  53     private static final String EXI_1_0_CAPABILITY_MARKER = "exi:1.0";
  54
  55     private static final Interner<Set<String>> INTERNER = Interners.newWeakInterner();
  56
  57     protected NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  58                                              final Promise<NetconfClientSession> promise,
  59                                              final Channel channel,
  60                                              final Timer timer,
  61                                              final NetconfClientSessionListener sessionListener,
  62                                              final long connectionTimeoutMillis) {
  63         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  64     }
  65
  66     @Override
  67     protected void handleMessage(final NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
  68         final NetconfClientSession session = getSessionForHelloMessage(netconfMessage);
  69         replaceHelloMessageInboundHandler(session);
  70
  71         // If exi should be used, try to initiate exi communication
  72         // Call negotiationSuccessFul after exi negotiation is finished successfully or not
  73         if (shouldUseExi(netconfMessage)) {
  74             LOG.debug("Netconf session {} should use exi.", session);
  75             NetconfStartExiMessage startExiMessage = (NetconfStartExiMessage) sessionPreferences.getStartExiMessage();
  76             tryToInitiateExi(session, startExiMessage);
  77         } else {
  78             // Exi is not supported, release session immediately
  79             LOG.debug("Netconf session {} isn't capable of using exi.", session);
  80             negotiationSuccessful(session);
  81         }
  82     }
  83
  84     /**
  85      * Initiates exi communication by sending start-exi message and waiting for positive/negative response.
  86      *
  87      * @param startExiMessage
  88      */
  89     void tryToInitiateExi(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
  90         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_DECODER,
  91                 ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER,
  92                 new ExiConfirmationInboundHandler(session, startExiMessage));
  93
  94         session.sendMessage(startExiMessage).addListener(new ChannelFutureListener() {
  95             @Override
  96             public void operationComplete(final ChannelFuture f) {
  97                 if (!f.isSuccess()) {
  98                     LOG.warn("Failed to send start-exi message {} on session {}", startExiMessage, this, f.cause());
  99                     channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 100                 } else {
 101                     LOG.trace("Start-exi message {} sent to socket on session {}", startExiMessage, this);
 102                 }
 103             }
 104         });
 105     }
 106
 107     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 108         return containsExi10Capability(helloMsg.getDocument())
 109                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 110     }
 111
 112     private static boolean containsExi10Capability(final Document doc) {
 113         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 114         for (int i = 0; i < nList.getLength(); i++) {
 115             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 116                 return true;
 117             }
 118         }
 119         return false;
 120     }
 121
 122     private static long extractSessionId(final Document doc) {
 123         String textContent = getSessionIdWithXPath(doc, sessionIdXPath);
 124         if (Strings.isNullOrEmpty(textContent)) {
 125             textContent = getSessionIdWithXPath(doc, sessionIdXPathNoNamespace);
 126             if (Strings.isNullOrEmpty(textContent)) {
 127                 throw new IllegalStateException("Session id not received from server, hello message: " + XmlUtil.toString(doc));
 128             }
 129         }
 130
 131         return Long.valueOf(textContent);
 132     }
 133
 134     private static String getSessionIdWithXPath(final Document doc, final XPathExpression sessionIdXPath) {
 135         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 136         return sessionIdNode != null ? sessionIdNode.getTextContent() : null;
 137     }
 138
 139     @Override
 140     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 141                                               final NetconfHelloMessage message) throws NetconfDocumentedException {
 142         final long sessionId = extractSessionId(message.getDocument());
 143
 144         // Copy here is important: it disconnects the strings from the document
 145         Set<String> capabilities = ImmutableSet.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message.getDocument()));
 146
 147         capabilities = INTERNER.intern(capabilities);
 148
 149         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 150     }
 151
 152     /**
 153      * Handler to process response for start-exi message
 154      */
 155     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 156         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 157
 158         private final NetconfClientSession session;
 159         private final NetconfStartExiMessage startExiMessage;
 160
 161         ExiConfirmationInboundHandler(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
 162             this.session = session;
 163             this.startExiMessage = startExiMessage;
 164         }
 165
 166         @Override
 167         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 168             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 169
 170             NetconfMessage netconfMessage = (NetconfMessage) msg;
 171
 172             // Ok response to start-exi, try to add exi handlers
 173             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 174                 LOG.trace("Positive response on start-exi call received on session {}", session);
 175                 try {
 176                     session.startExiCommunication(startExiMessage);
 177                 } catch (RuntimeException e) {
 178                     // Unable to add exi, continue without exi
 179                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session {}", session, e);
 180                 }
 181
 182                 // Error response
 183             } else if(NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 184                 LOG.warn(
 185                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 186                         netconfMessage, session);
 187
 188                 // Unexpected response to start-exi, throwing message away, continue without exi
 189             } else {
 190                 LOG.warn("Unexpected response to start-exi message, should be ok, was {}, " +
 191                          "Communication will continue without exi and response message will be thrown away on session {}",
 192                          netconfMessage, session);
 193             }
 194
 195             negotiationSuccessful(session);
 196         }
 197     }
 198
 199 }