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 edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  16 import io.netty.channel.Channel;
  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 import java.util.Set;
  22 import javax.xml.xpath.XPathConstants;
  23 import javax.xml.xpath.XPathExpression;
  24 import org.opendaylight.netconf.api.NetconfClientSessionPreferences;
  25 import org.opendaylight.netconf.api.NetconfDocumentedException;
  26 import org.opendaylight.netconf.api.NetconfMessage;
  27 import org.opendaylight.netconf.api.messages.NetconfHelloMessage;
  28 import org.opendaylight.netconf.api.xml.XmlNetconfConstants;
  29 import org.opendaylight.netconf.api.xml.XmlUtil;
  30 import org.opendaylight.netconf.nettyutil.AbstractChannelInitializer;
  31 import org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator;
  32 import org.opendaylight.netconf.nettyutil.handler.exi.NetconfStartExiMessage;
  33 import org.opendaylight.netconf.util.messages.NetconfMessageUtil;
  34 import org.opendaylight.netconf.util.xml.XMLNetconfUtil;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37 import org.w3c.dom.Document;
  38 import org.w3c.dom.Node;
  39 import org.w3c.dom.NodeList;
  40
  41 public class NetconfClientSessionNegotiator extends
  42         AbstractNetconfSessionNegotiator<NetconfClientSessionPreferences, NetconfClientSession,
  43                 NetconfClientSessionListener> {
  44     private static final Logger LOG = LoggerFactory.getLogger(NetconfClientSessionNegotiator.class);
  45
  46     private static final XPathExpression SESSION_ID_X_PATH = XMLNetconfUtil
  47             .compileXPath("/netconf:hello/netconf:session-id");
  48
  49     private static final XPathExpression SESSION_ID_X_PATH_NO_NAMESPACE = XMLNetconfUtil
  50             .compileXPath("/hello/session-id");
  51
  52     private static final String EXI_1_0_CAPABILITY_MARKER = "exi:1.0";
  53
  54     private static final Interner<Set<String>> INTERNER = Interners.newWeakInterner();
  55
  56     protected NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  57                                              final Promise<NetconfClientSession> promise,
  58                                              final Channel channel,
  59                                              final Timer timer,
  60                                              final NetconfClientSessionListener sessionListener,
  61                                              final long connectionTimeoutMillis) {
  62         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  63     }
  64
  65     @SuppressWarnings("checkstyle:IllegalCatch")
  66     @Override
  67     @SuppressFBWarnings("BC_UNCONFIRMED_CAST")
  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 on channel {}", channel, 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         final NetconfMessage startExiMessage = sessionPreferences.getStartExiMessage();
  85         if (shouldUseExi(netconfMessage) && startExiMessage instanceof NetconfStartExiMessage) {
  86             LOG.debug("Netconf session {} should use exi.", session);
  87             tryToInitiateExi(session, (NetconfStartExiMessage) 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(channelFuture -> {
 106             if (!channelFuture.isSuccess()) {
 107                 LOG.warn("Failed to send start-exi message {} on session {}", startExiMessage, session,
 108                         channelFuture.cause());
 109                 channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 110             } else {
 111                 LOG.trace("Start-exi message {} sent to socket on session {}", startExiMessage, session);
 112             }
 113         });
 114     }
 115
 116     @SuppressFBWarnings("BC_UNCONFIRMED_CAST")
 117     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 118         return containsExi10Capability(helloMsg.getDocument())
 119                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 120     }
 121
 122     private static boolean containsExi10Capability(final Document doc) {
 123         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 124         for (int i = 0; i < nList.getLength(); i++) {
 125             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 126                 return true;
 127             }
 128         }
 129         return false;
 130     }
 131
 132     private static long extractSessionId(final Document doc) {
 133         String textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH);
 134         if (Strings.isNullOrEmpty(textContent)) {
 135             textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH_NO_NAMESPACE);
 136             if (Strings.isNullOrEmpty(textContent)) {
 137                 throw new IllegalStateException("Session id not received from server, hello message: " + XmlUtil
 138                         .toString(doc));
 139             }
 140         }
 141
 142         return Long.parseLong(textContent);
 143     }
 144
 145     private static String getSessionIdWithXPath(final Document doc, final XPathExpression sessionIdXPath) {
 146         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 147         return sessionIdNode != null ? sessionIdNode.getTextContent() : null;
 148     }
 149
 150     @Override
 151     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 152                                               final NetconfHelloMessage message) {
 153         final long sessionId = extractSessionId(message.getDocument());
 154
 155         // Copy here is important: it disconnects the strings from the document
 156         Set<String> capabilities = ImmutableSet.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message
 157                 .getDocument()));
 158
 159         capabilities = INTERNER.intern(capabilities);
 160
 161         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 162     }
 163
 164     /**
 165      * Handler to process response for start-exi message.
 166      */
 167     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 168         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 169
 170         private final NetconfClientSession session;
 171         private final NetconfStartExiMessage startExiMessage;
 172
 173         ExiConfirmationInboundHandler(final NetconfClientSession session,
 174                                       final NetconfStartExiMessage startExiMessage) {
 175             this.session = session;
 176             this.startExiMessage = startExiMessage;
 177         }
 178
 179         @SuppressWarnings("checkstyle:IllegalCatch")
 180         @Override
 181         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 182             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 183
 184             NetconfMessage netconfMessage = (NetconfMessage) msg;
 185
 186             // Ok response to start-exi, try to add exi handlers
 187             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 188                 LOG.trace("Positive response on start-exi call received on session {}", session);
 189                 try {
 190                     session.startExiCommunication(startExiMessage);
 191                 } catch (RuntimeException e) {
 192                     // Unable to add exi, continue without exi
 193                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session "
 194                             + "{}", session, e);
 195                 }
 196
 197                 // Error response
 198             } else if (NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 199                 LOG.warn(
 200                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 201                         netconfMessage, session);
 202
 203                 // Unexpected response to start-exi, throwing message away, continue without exi
 204             } else {
 205                 LOG.warn("Unexpected response to start-exi message, should be ok, was {}, "
 206                         + "Communication will continue without exi "
 207                         + "and response message will be thrown away on session {}",
 208                         netconfMessage, session);
 209             }
 210
 211             negotiationSuccessful(session);
 212         }
 213     }
 214
 215 }