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 // Non-final for mocking
  41 class NetconfClientSessionNegotiator
  42         extends 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     NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  57             final Promise<NetconfClientSession> promise, final Channel channel, final Timer timer,
  58             final NetconfClientSessionListener sessionListener, final long connectionTimeoutMillis) {
  59         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  60     }
  61
  62     @SuppressWarnings("checkstyle:IllegalCatch")
  63     @SuppressFBWarnings(value = "BC_UNCONFIRMED_CAST",
  64         justification = "SpotBugs does not understand generic cast of sessionPreferences")
  65     @Override
  66     protected void handleMessage(final NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
  67         if (!ifNegotiatedAlready()) {
  68             LOG.debug("Server hello message received, starting negotiation on channel {}", channel);
  69             try {
  70                 startNegotiation();
  71             } catch (final Exception e) {
  72                 LOG.warn("Unexpected negotiation failure on channel {}", channel, e);
  73                 negotiationFailed(e);
  74                 return;
  75             }
  76         }
  77         final NetconfClientSession session = getSessionForHelloMessage(netconfMessage);
  78         replaceHelloMessageInboundHandler(session);
  79
  80         // If exi should be used, try to initiate exi communication
  81         // Call negotiationSuccessFul after exi negotiation is finished successfully or not
  82         final NetconfMessage startExiMessage = sessionPreferences.getStartExiMessage();
  83         if (shouldUseExi(netconfMessage) && startExiMessage instanceof NetconfStartExiMessage) {
  84             LOG.debug("Netconf session {} should use exi.", session);
  85             tryToInitiateExi(session, (NetconfStartExiMessage) startExiMessage);
  86         } else {
  87             // Exi is not supported, release session immediately
  88             LOG.debug("Netconf session {} isn't capable of using exi.", session);
  89             negotiationSuccessful(session);
  90         }
  91     }
  92
  93     /**
  94      * Initiates exi communication by sending start-exi message and waiting for positive/negative response.
  95      *
  96      * @param startExiMessage Exi message for initilization of exi communication.
  97      */
  98     void tryToInitiateExi(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
  99         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_DECODER,
 100                 ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER,
 101                 new ExiConfirmationInboundHandler(session, startExiMessage));
 102
 103         session.sendMessage(startExiMessage).addListener(channelFuture -> {
 104             if (!channelFuture.isSuccess()) {
 105                 LOG.warn("Failed to send start-exi message {} on session {}", startExiMessage, session,
 106                         channelFuture.cause());
 107                 channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 108             } else {
 109                 LOG.trace("Start-exi message {} sent to socket on session {}", startExiMessage, session);
 110             }
 111         });
 112     }
 113
 114     @SuppressFBWarnings(value = "BC_UNCONFIRMED_CAST",
 115         justification = "SpotBugs does not understand generic cast of sessionPreferences")
 116     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 117         return containsExi10Capability(helloMsg.getDocument())
 118                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 119     }
 120
 121     private static boolean containsExi10Capability(final Document doc) {
 122         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 123         for (int i = 0; i < nList.getLength(); i++) {
 124             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 125                 return true;
 126             }
 127         }
 128         return false;
 129     }
 130
 131     private static long extractSessionId(final Document doc) {
 132         String textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH);
 133         if (Strings.isNullOrEmpty(textContent)) {
 134             textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH_NO_NAMESPACE);
 135             if (Strings.isNullOrEmpty(textContent)) {
 136                 throw new IllegalStateException("Session id not received from server, hello message: " + XmlUtil
 137                         .toString(doc));
 138             }
 139         }
 140
 141         return Long.parseLong(textContent);
 142     }
 143
 144     private static String getSessionIdWithXPath(final Document doc, final XPathExpression sessionIdXPath) {
 145         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 146         return sessionIdNode != null ? sessionIdNode.getTextContent() : null;
 147     }
 148
 149     @Override
 150     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 151                                               final NetconfHelloMessage message) {
 152         final long sessionId = extractSessionId(message.getDocument());
 153
 154         // Copy here is important: it disconnects the strings from the document
 155         Set<String> capabilities = ImmutableSet.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message
 156                 .getDocument()));
 157
 158         capabilities = INTERNER.intern(capabilities);
 159
 160         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 161     }
 162
 163     /**
 164      * Handler to process response for start-exi message.
 165      */
 166     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 167         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 168
 169         private final NetconfClientSession session;
 170         private final NetconfStartExiMessage startExiMessage;
 171
 172         ExiConfirmationInboundHandler(final NetconfClientSession session,
 173                                       final NetconfStartExiMessage startExiMessage) {
 174             this.session = session;
 175             this.startExiMessage = startExiMessage;
 176         }
 177
 178         @SuppressWarnings("checkstyle:IllegalCatch")
 179         @Override
 180         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 181             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 182
 183             NetconfMessage netconfMessage = (NetconfMessage) msg;
 184
 185             // Ok response to start-exi, try to add exi handlers
 186             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 187                 LOG.trace("Positive response on start-exi call received on session {}", session);
 188                 try {
 189                     session.startExiCommunication(startExiMessage);
 190                 } catch (RuntimeException e) {
 191                     // Unable to add exi, continue without exi
 192                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session "
 193                             + "{}", session, e);
 194                 }
 195
 196                 // Error response
 197             } else if (NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 198                 LOG.warn(
 199                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 200                         netconfMessage, session);
 201
 202                 // Unexpected response to start-exi, throwing message away, continue without exi
 203             } else {
 204                 LOG.warn("Unexpected response to start-exi message, should be ok, was {}, "
 205                         + "Communication will continue without exi "
 206                         + "and response message will be thrown away on session {}",
 207                         netconfMessage, session);
 208             }
 209
 210             negotiationSuccessful(session);
 211         }
 212     }
 213
 214 }