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.ChannelFuture;
  18 import io.netty.channel.ChannelFutureListener;
  19 import io.netty.channel.ChannelHandlerContext;
  20 import io.netty.channel.ChannelInboundHandlerAdapter;
  21 import io.netty.util.Timer;
  22 import io.netty.util.concurrent.Promise;
  23 import java.util.Set;
  24 import javax.xml.xpath.XPathConstants;
  25 import javax.xml.xpath.XPathExpression;
  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.api.xml.XmlUtil;
  32 import org.opendaylight.netconf.nettyutil.AbstractChannelInitializer;
  33 import org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator;
  34 import org.opendaylight.netconf.nettyutil.handler.exi.NetconfStartExiMessage;
  35 import org.opendaylight.netconf.util.messages.NetconfMessageUtil;
  36 import org.opendaylight.netconf.util.xml.XMLNetconfUtil;
  37 import org.slf4j.Logger;
  38 import org.slf4j.LoggerFactory;
  39 import org.w3c.dom.Document;
  40 import org.w3c.dom.Node;
  41 import org.w3c.dom.NodeList;
  42
  43 public class NetconfClientSessionNegotiator extends
  44         AbstractNetconfSessionNegotiator<NetconfClientSessionPreferences, NetconfClientSession,
  45                 NetconfClientSessionListener> {
  46     private static final Logger LOG = LoggerFactory.getLogger(NetconfClientSessionNegotiator.class);
  47
  48     private static final XPathExpression SESSION_ID_X_PATH = XMLNetconfUtil
  49             .compileXPath("/netconf:hello/netconf:session-id");
  50
  51     private static final XPathExpression SESSION_ID_X_PATH_NO_NAMESPACE = XMLNetconfUtil
  52             .compileXPath("/hello/session-id");
  53
  54     private static final String EXI_1_0_CAPABILITY_MARKER = "exi:1.0";
  55
  56     private static final Interner<Set<String>> INTERNER = Interners.newWeakInterner();
  57
  58     protected NetconfClientSessionNegotiator(final NetconfClientSessionPreferences sessionPreferences,
  59                                              final Promise<NetconfClientSession> promise,
  60                                              final Channel channel,
  61                                              final Timer timer,
  62                                              final NetconfClientSessionListener sessionListener,
  63                                              final long connectionTimeoutMillis) {
  64         super(sessionPreferences, promise, channel, timer, sessionListener, connectionTimeoutMillis);
  65     }
  66
  67     @SuppressWarnings("checkstyle:IllegalCatch")
  68     @Override
  69     @SuppressFBWarnings("BC_UNCONFIRMED_CAST")
  70     protected void handleMessage(final NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
  71         if (!ifNegotiatedAlready()) {
  72             LOG.debug("Server hello message received, starting negotiation on channel {}", channel);
  73             try {
  74                 startNegotiation();
  75             } catch (final Exception e) {
  76                 LOG.warn("Unexpected negotiation failure on channel {}", channel, e);
  77                 negotiationFailed(e);
  78                 return;
  79             }
  80         }
  81         final NetconfClientSession session = getSessionForHelloMessage(netconfMessage);
  82         replaceHelloMessageInboundHandler(session);
  83
  84         // If exi should be used, try to initiate exi communication
  85         // Call negotiationSuccessFul after exi negotiation is finished successfully or not
  86         final NetconfMessage startExiMessage = sessionPreferences.getStartExiMessage();
  87         if (shouldUseExi(netconfMessage) && startExiMessage instanceof NetconfStartExiMessage) {
  88             LOG.debug("Netconf session {} should use exi.", session);
  89             tryToInitiateExi(session, (NetconfStartExiMessage) startExiMessage);
  90         } else {
  91             // Exi is not supported, release session immediately
  92             LOG.debug("Netconf session {} isn't capable of using exi.", session);
  93             negotiationSuccessful(session);
  94         }
  95     }
  96
  97     /**
  98      * Initiates exi communication by sending start-exi message and waiting for positive/negative response.
  99      *
 100      * @param startExiMessage Exi message for initilization of exi communication.
 101      */
 102     void tryToInitiateExi(final NetconfClientSession session, final NetconfStartExiMessage startExiMessage) {
 103         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_DECODER,
 104                 ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER,
 105                 new ExiConfirmationInboundHandler(session, startExiMessage));
 106
 107         session.sendMessage(startExiMessage).addListener(new ChannelFutureListener() {
 108             @Override
 109             public void operationComplete(final ChannelFuture channelFuture) {
 110                 if (!channelFuture.isSuccess()) {
 111                     LOG.warn("Failed to send start-exi message {} on session {}", startExiMessage, this,
 112                             channelFuture.cause());
 113                     channel.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 114                 } else {
 115                     LOG.trace("Start-exi message {} sent to socket on session {}", startExiMessage, this);
 116                 }
 117             }
 118         });
 119     }
 120
 121     @SuppressFBWarnings("BC_UNCONFIRMED_CAST")
 122     private boolean shouldUseExi(final NetconfHelloMessage helloMsg) {
 123         return containsExi10Capability(helloMsg.getDocument())
 124                 && containsExi10Capability(sessionPreferences.getHelloMessage().getDocument());
 125     }
 126
 127     private static boolean containsExi10Capability(final Document doc) {
 128         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 129         for (int i = 0; i < nList.getLength(); i++) {
 130             if (nList.item(i).getTextContent().contains(EXI_1_0_CAPABILITY_MARKER)) {
 131                 return true;
 132             }
 133         }
 134         return false;
 135     }
 136
 137     private static long extractSessionId(final Document doc) {
 138         String textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH);
 139         if (Strings.isNullOrEmpty(textContent)) {
 140             textContent = getSessionIdWithXPath(doc, SESSION_ID_X_PATH_NO_NAMESPACE);
 141             if (Strings.isNullOrEmpty(textContent)) {
 142                 throw new IllegalStateException("Session id not received from server, hello message: " + XmlUtil
 143                         .toString(doc));
 144             }
 145         }
 146
 147         return Long.parseLong(textContent);
 148     }
 149
 150     private static String getSessionIdWithXPath(final Document doc, final XPathExpression sessionIdXPath) {
 151         final Node sessionIdNode = (Node) XmlUtil.evaluateXPath(sessionIdXPath, doc, XPathConstants.NODE);
 152         return sessionIdNode != null ? sessionIdNode.getTextContent() : null;
 153     }
 154
 155     @Override
 156     protected NetconfClientSession getSession(final NetconfClientSessionListener sessionListener, final Channel channel,
 157                                               final NetconfHelloMessage message) {
 158         final long sessionId = extractSessionId(message.getDocument());
 159
 160         // Copy here is important: it disconnects the strings from the document
 161         Set<String> capabilities = ImmutableSet.copyOf(NetconfMessageUtil.extractCapabilitiesFromHello(message
 162                 .getDocument()));
 163
 164         capabilities = INTERNER.intern(capabilities);
 165
 166         return new NetconfClientSession(sessionListener, channel, sessionId, capabilities);
 167     }
 168
 169     /**
 170      * Handler to process response for start-exi message.
 171      */
 172     private final class ExiConfirmationInboundHandler extends ChannelInboundHandlerAdapter {
 173         private static final String EXI_CONFIRMED_HANDLER = "exiConfirmedHandler";
 174
 175         private final NetconfClientSession session;
 176         private final NetconfStartExiMessage startExiMessage;
 177
 178         ExiConfirmationInboundHandler(final NetconfClientSession session,
 179                                       final NetconfStartExiMessage startExiMessage) {
 180             this.session = session;
 181             this.startExiMessage = startExiMessage;
 182         }
 183
 184         @SuppressWarnings("checkstyle:IllegalCatch")
 185         @Override
 186         public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
 187             ctx.pipeline().remove(ExiConfirmationInboundHandler.EXI_CONFIRMED_HANDLER);
 188
 189             NetconfMessage netconfMessage = (NetconfMessage) msg;
 190
 191             // Ok response to start-exi, try to add exi handlers
 192             if (NetconfMessageUtil.isOKMessage(netconfMessage)) {
 193                 LOG.trace("Positive response on start-exi call received on session {}", session);
 194                 try {
 195                     session.startExiCommunication(startExiMessage);
 196                 } catch (RuntimeException e) {
 197                     // Unable to add exi, continue without exi
 198                     LOG.warn("Unable to start exi communication, Communication will continue without exi on session "
 199                             + "{}", session, e);
 200                 }
 201
 202                 // Error response
 203             } else if (NetconfMessageUtil.isErrorMessage(netconfMessage)) {
 204                 LOG.warn(
 205                         "Error response to start-exi message {}, Communication will continue without exi on session {}",
 206                         netconfMessage, session);
 207
 208                 // Unexpected response to start-exi, throwing message away, continue without exi
 209             } else {
 210                 LOG.warn("Unexpected response to start-exi message, should be ok, was {}, "
 211                         + "Communication will continue without exi "
 212                         + "and response message will be thrown away on session {}",
 213                         netconfMessage, session);
 214             }
 215
 216             negotiationSuccessful(session);
 217         }
 218     }
 219
 220 }