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