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