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,
  44                 NetconfClientSessionListener> {
  45     private static final Logger LOG = LoggerFactory.getLogger(NetconfClientSessionNegotiator.class);
  46
  47     private static final XPathExpression SESSION_ID_X_PATH = XMLNetconfUtil
  48             .compileXPath("/netconf:hello/netconf:session-id");
  49
  50     private static final XPathExpression SESSION_ID_X_PATH_NO_NAMESPACE = 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     @SuppressWarnings("checkstyle:IllegalCatch")
  67     @Override
  68     protected void handleMessage(final NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
  69         if (!ifNegotiatedAlready()) {
  70             LOG.debug("Server hello message received, starting negotiation on channel {}", channel);
  71             try {
  72                 startNegotiation();
  73             } catch (final Exception e) {
  74                 LOG.warn("Unexpected negotiation failure", e);
  75                 negotiationFailed(e);
  76                 return;
  77             }
  78         }
  79         final NetconfClientSession session = getSessionForHelloMessage(netconfMessage);
  80         replaceHelloMessageInboundHandler(session);
  81
  82         // If exi should be used, try to initiate exi communication
  83         // Call negotiationSuccessFul after exi negotiation is finished successfully or not
  84         if (shouldUseExi(netconfMessage)) {
  85             LOG.debug("Netconf session {} should use exi.", session);
  86             NetconfStartExiMessage startExiMessage = (NetconfStartExiMessage) sessionPreferences.getStartExiMessage();
  87             tryToInitiateExi(session, startExiMessage);
  88         } else {
  89             // Exi is not supported, release session immediately
  90             LOG.debug("Netconf session {} isn't capable of using exi.", session);
  91             negotiationSuccessful(session);
  92         }
  93     }
  94
  95     /**
  96      * Initiates exi communication by sending start-exi message and waiting for positive/negative response.
  97      *
  98      * @param startExiMessage Exi message for initilization of exi communication.
  99      */
 100     void tryToInitiateExi(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
 101         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_DECODER,
 102                 ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER,
 103                 new ExiConfirmationInboundHandler(session, startExiMessage));
 104
 105         session.sendMessage(startExiMessage).addListener(new ChannelFutureListener() {
 106             @Override
 107             public void operationComplete(final ChannelFuture channelFuture) {
 108                 if (!channelFuture.isSuccess()) {
 109                     LOG.warn("Failed to send start-exi message {} on session {}", startExiMessage, this,
 110                             channelFuture.cause());
 111                     channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 112                 } else {
 113                     LOG.trace("Start-exi message {} sent to socket on session {}", startExiMessage, this);
 114                 }
 115             }
 116         });
 117     }
 118
 119     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 120         return containsExi10Capability(helloMsg.getDocument())
 121                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 122     }
 123
 124     private static boolean containsExi10Capability(final Document doc) {
 125         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 126         for (int i = 0; i < nList.getLength(); i++) {
 127             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 128                 return true;
 129             }
 130         }
 131         return false;
 132     }
 133
 134     private static long extractSessionId(final Document doc) {
 135         String textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH);
 136         if (Strings.isNullOrEmpty(textContent)) {
 137             textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH_NO_NAMESPACE);
 138             if (Strings.isNullOrEmpty(textContent)) {
 139                 throw new IllegalStateException("Session id not received from server, hello message: " + XmlUtil
 140                         .toString(doc));
 141             }
 142         }
 143
 144         return Long.valueOf(textContent);
 145     }
 146
 147     private static String getSessionIdWithXPath(final Document doc, final XPathExpression sessionIdXPath) {
 148         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 149         return sessionIdNode != null ? sessionIdNode.getTextContent() : null;
 150     }
 151
 152     @Override
 153     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 154                                               final NetconfHelloMessage message) throws NetconfDocumentedException {
 155         final long sessionId = extractSessionId(message.getDocument());
 156
 157         // Copy here is important: it disconnects the strings from the document
 158         Set<String> capabilities = ImmutableSet.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message
 159                 .getDocument()));
 160
 161         capabilities = INTERNER.intern(capabilities);
 162
 163         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 164     }
 165
 166     /**
 167      * Handler to process response for start-exi message.
 168      */
 169     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 170         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 171
 172         private final NetconfClientSession session;
 173         private final NetconfStartExiMessage startExiMessage;
 174
 175         ExiConfirmationInboundHandler(final NetconfClientSession session,
 176                                       final NetconfStartExiMessage startExiMessage) {
 177             this.session = session;
 178             this.startExiMessage = startExiMessage;
 179         }
 180
 181         @SuppressWarnings("checkstyle:IllegalCatch")
 182         @Override
 183         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 184             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 185
 186             NetconfMessage netconfMessage = (NetconfMessage) msg;
 187
 188             // Ok response to start-exi, try to add exi handlers
 189             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 190                 LOG.trace("Positive response on start-exi call received on session {}", session);
 191                 try {
 192                     session.startExiCommunication(startExiMessage);
 193                 } catch (RuntimeException e) {
 194                     // Unable to add exi, continue without exi
 195                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session "
 196                             + "{}", session, e);
 197                 }
 198
 199                 // Error response
 200             } else if (NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 201                 LOG.warn(
 202                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 203                         netconfMessage, session);
 204
 205                 // Unexpected response to start-exi, throwing message away, continue without exi
 206             } else {
 207                 LOG.warn("Unexpected response to start-exi message, should be ok, was {}, "
 208                         + "Communication will continue without exi "
 209                         + "and response message will be thrown away on session {}",
 210                         netconfMessage, session);
 211             }
 212
 213             negotiationSuccessful(session);
 214         }
 215     }
 216
 217 }