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