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 package org.opendaylight.netconf.client;
   9
  10 import com.google.common.base.Strings;
  11 import com.google.common.collect.ImmutableSet;
  12 import com.google.common.collect.Interner;
  13 import com.google.common.collect.Interners;
  14 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  15 import io.netty.channel.Channel;
  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.Set;
  21 import javax.xml.xpath.XPathConstants;
  22 import javax.xml.xpath.XPathExpression;
  23 import org.opendaylight.netconf.api.NetconfClientSessionPreferences;
  24 import org.opendaylight.netconf.api.NetconfDocumentedException;
  25 import org.opendaylight.netconf.api.NetconfMessage;
  26 import org.opendaylight.netconf.api.messages.NetconfHelloMessage;
  27 import org.opendaylight.netconf.api.xml.XmlNetconfConstants;
  28 import org.opendaylight.netconf.api.xml.XmlUtil;
  29 import org.opendaylight.netconf.nettyutil.AbstractChannelInitializer;
  30 import org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator;
  31 import org.opendaylight.netconf.nettyutil.handler.exi.NetconfStartExiMessage;
  32 import org.opendaylight.netconf.util.messages.NetconfMessageUtil;
  33 import org.opendaylight.netconf.util.xml.XMLNetconfUtil;
  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,
  42                 NetconfClientSessionListener> {
  43     private static final Logger LOG = LoggerFactory.getLogger(NetconfClientSessionNegotiator.class);
  44
  45     private static final XPathExpression SESSION_ID_X_PATH = XMLNetconfUtil
  46             .compileXPath("/netconf:hello/netconf:session-id");
  47
  48     private static final XPathExpression SESSION_ID_X_PATH_NO_NAMESPACE = XMLNetconfUtil
  49             .compileXPath("/hello/session-id");
  50
  51     private static final String EXI_1_0_CAPABILITY_MARKER = "exi:1.0";
  52
  53     private static final Interner<Set<String>> INTERNER = Interners.newWeakInterner();
  54
  55     protected NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  56                                              final Promise<NetconfClientSession> promise,
  57                                              final Channel channel,
  58                                              final Timer timer,
  59                                              final NetconfClientSessionListener sessionListener,
  60                                              final long connectionTimeoutMillis) {
  61         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  62     }
  63
  64     @SuppressWarnings("checkstyle:IllegalCatch")
  65     @SuppressFBWarnings(value = "BC_UNCONFIRMED_CAST",
  66         justification = "SpotBugs does not understand generic cast of sessionPreferences")
  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 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(value = "BC_UNCONFIRMED_CAST",
 117         justification = "SpotBugs does not understand generic cast of sessionPreferences")
 118     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 119         return containsExi10Capability(helloMsg.getDocument())
 120                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 121     }
 122
 123     private static boolean containsExi10Capability(final Document doc) {
 124         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 125         for (int i = 0; i < nList.getLength(); i++) {
 126             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 127                 return true;
 128             }
 129         }
 130         return false;
 131     }
 132
 133     private static long extractSessionId(final Document doc) {
 134         String textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH);
 135         if (Strings.isNullOrEmpty(textContent)) {
 136             textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH_NO_NAMESPACE);
 137             if (Strings.isNullOrEmpty(textContent)) {
 138                 throw new IllegalStateException("Session id not received from server, hello message: " + XmlUtil
 139                         .toString(doc));
 140             }
 141         }
 142
 143         return Long.parseLong(textContent);
 144     }
 145
 146     private static String getSessionIdWithXPath(final Document doc, final XPathExpression sessionIdXPath) {
 147         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 148         return sessionIdNode != null ? sessionIdNode.getTextContent() : null;
 149     }
 150
 151     @Override
 152     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 153                                               final NetconfHelloMessage message) {
 154         final long sessionId = extractSessionId(message.getDocument());
 155
 156         // Copy here is important: it disconnects the strings from the document
 157         Set<String> capabilities = ImmutableSet.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message
 158                 .getDocument()));
 159
 160         capabilities = INTERNER.intern(capabilities);
 161
 162         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 163     }
 164
 165     /**
 166      * Handler to process response for start-exi message.
 167      */
 168     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 169         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 170
 171         private final NetconfClientSession session;
 172         private final NetconfStartExiMessage startExiMessage;
 173
 174         ExiConfirmationInboundHandler(final NetconfClientSession session,
 175                                       final NetconfStartExiMessage startExiMessage) {
 176             this.session = session;
 177             this.startExiMessage = startExiMessage;
 178         }
 179
 180         @SuppressWarnings("checkstyle:IllegalCatch")
 181         @Override
 182         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 183             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 184
 185             NetconfMessage netconfMessage = (NetconfMessage) msg;
 186
 187             // Ok response to start-exi, try to add exi handlers
 188             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 189                 LOG.trace("Positive response on start-exi call received on session {}", session);
 190                 try {
 191                     session.startExiCommunication(startExiMessage);
 192                 } catch (RuntimeException e) {
 193                     // Unable to add exi, continue without exi
 194                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session "
 195                             + "{}", session, e);
 196                 }
 197
 198                 // Error response
 199             } else if (NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 200                 LOG.warn(
 201                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 202                         netconfMessage, session);
 203
 204                 // Unexpected response to start-exi, throwing message away, continue without exi
 205             } else {
 206                 LOG.warn("Unexpected response to start-exi message, should be ok, was {}, "
 207                         + "Communication will continue without exi "
 208                         + "and response message will be thrown away on session {}",
 209                         netconfMessage, session);
 210             }
 211
 212             negotiationSuccessful(session);
 213         }
 214     }
 215
 216 }