opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfXMLToHelloMessageDecoder.java

   1 /*
   2  * Copyright (c) 2014 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.controller.netconf.nettyutil.handler;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Charsets;
  12 import com.google.common.base.Preconditions;
  13 import com.google.common.collect.ImmutableList;
  14 import com.google.common.collect.Lists;
  15 import io.netty.buffer.ByteBuf;
  16 import io.netty.buffer.ByteBufUtil;
  17 import io.netty.channel.ChannelHandlerContext;
  18 import io.netty.handler.codec.ByteToMessageDecoder;
  19 import java.io.ByteArrayInputStream;
  20 import java.io.IOException;
  21 import java.nio.ByteBuffer;
  22 import java.util.Arrays;
  23 import java.util.List;
  24 import org.opendaylight.controller.netconf.api.NetconfDocumentedException;
  25 import org.opendaylight.controller.netconf.api.NetconfMessage;
  26 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  27 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessageAdditionalHeader;
  28 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31 import org.w3c.dom.Document;
  32 import org.xml.sax.SAXException;
  33
  34 /**
  35  * Customized NetconfXMLToMessageDecoder that reads additional header with
  36  * session metadata from
  37  * {@link org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage}
  38  *
  39  *
  40  * This handler should be replaced in pipeline by regular message handler as last step of negotiation.
  41  * It serves as a message barrier and halts all non-hello netconf messages.
  42  * Netconf messages after hello should be processed once the negotiation succeeded.
  43  *
  44  */
  45 public final class NetconfXMLToHelloMessageDecoder extends ByteToMessageDecoder {
  46     private static final Logger LOG = LoggerFactory.getLogger(NetconfXMLToHelloMessageDecoder.class);
  47
  48     private static final List<byte[]> POSSIBLE_ENDS = ImmutableList.of(
  49             new byte[] { ']', '\n' },
  50             new byte[] { ']', '\r', '\n' });
  51     private static final List<byte[]> POSSIBLE_STARTS = ImmutableList.of(
  52             new byte[] { '[' },
  53             new byte[] { '\r', '\n', '[' },
  54             new byte[] { '\n', '[' });
  55
  56     // State variables do not have to by synchronized
  57     // Netty uses always the same (1) thread per pipeline
  58     // We use instance of this per pipeline
  59     private List<NetconfMessage> nonHelloMessages = Lists.newArrayList();
  60     private boolean helloReceived = false;
  61
  62     @Override
  63     @VisibleForTesting
  64     public void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws IOException, SAXException, NetconfDocumentedException {
  65         if (in.readableBytes() == 0) {
  66             LOG.debug("No more content in incoming buffer.");
  67             return;
  68         }
  69
  70         in.markReaderIndex();
  71         try {
  72             LOG.trace("Received to decode: {}", ByteBufUtil.hexDump(in));
  73             byte[] bytes = new byte[in.readableBytes()];
  74             in.readBytes(bytes);
  75
  76             logMessage(bytes);
  77
  78             // Extract bytes containing header with additional metadata
  79             String additionalHeader = null;
  80             if (startsWithAdditionalHeader(bytes)) {
  81                 // Auth information containing username, ip address... extracted for monitoring
  82                 int endOfAuthHeader = getAdditionalHeaderEndIndex(bytes);
  83                 if (endOfAuthHeader > -1) {
  84                     byte[] additionalHeaderBytes = Arrays.copyOfRange(bytes, 0, endOfAuthHeader + 2);
  85                     additionalHeader = additionalHeaderToString(additionalHeaderBytes);
  86                     bytes = Arrays.copyOfRange(bytes, endOfAuthHeader + 2, bytes.length);
  87                 }
  88             }
  89
  90             Document doc = XmlUtil.readXmlToDocument(new ByteArrayInputStream(bytes));
  91
  92             final NetconfMessage message = getNetconfMessage(additionalHeader, doc);
  93             if (message instanceof NetconfHelloMessage) {
  94                 Preconditions.checkState(helloReceived == false,
  95                         "Multiple hello messages received, unexpected hello: %s",
  96                         XmlUtil.toString(message.getDocument()));
  97                 out.add(message);
  98                 helloReceived = true;
  99             // Non hello message, suspend the message and insert into cache
 100             } else {
 101                 Preconditions.checkState(helloReceived, "Hello message not received, instead received: %s",
 102                         XmlUtil.toString(message.getDocument()));
 103                 LOG.debug("Netconf message received during negotiation, caching {}",
 104                         XmlUtil.toString(message.getDocument()));
 105                 nonHelloMessages.add(message);
 106             }
 107         } finally {
 108             in.discardReadBytes();
 109         }
 110     }
 111
 112     private NetconfMessage getNetconfMessage(final String additionalHeader, final Document doc) throws NetconfDocumentedException {
 113         NetconfMessage msg = new NetconfMessage(doc);
 114         if(NetconfHelloMessage.isHelloMessage(msg)) {
 115             if (additionalHeader != null) {
 116                 return new NetconfHelloMessage(doc, NetconfHelloMessageAdditionalHeader.fromString(additionalHeader));
 117             } else {
 118                 return new NetconfHelloMessage(doc);
 119             }
 120         }
 121
 122         return msg;
 123     }
 124
 125     private int getAdditionalHeaderEndIndex(byte[] bytes) {
 126         for (byte[] possibleEnd : POSSIBLE_ENDS) {
 127             int idx = findByteSequence(bytes, possibleEnd);
 128
 129             if (idx != -1) {
 130                 return idx;
 131             }
 132         }
 133
 134         return -1;
 135     }
 136
 137     private static int findByteSequence(final byte[] bytes, final byte[] sequence) {
 138         if (bytes.length < sequence.length) {
 139             throw new IllegalArgumentException("Sequence to be found is longer than the given byte array.");
 140         }
 141         if (bytes.length == sequence.length) {
 142             if (Arrays.equals(bytes, sequence)) {
 143                 return 0;
 144             } else {
 145                 return -1;
 146             }
 147         }
 148         int j = 0;
 149         for (int i = 0; i < bytes.length; i++) {
 150             if (bytes[i] == sequence[j]) {
 151                 j++;
 152                 if (j == sequence.length) {
 153                     return i - j + 1;
 154                 }
 155             } else {
 156                 j = 0;
 157             }
 158         }
 159         return -1;
 160     }
 161
 162
 163     private void logMessage(byte[] bytes) {
 164         String s = Charsets.UTF_8.decode(ByteBuffer.wrap(bytes)).toString();
 165         LOG.debug("Parsing message \n{}", s);
 166     }
 167
 168     private boolean startsWithAdditionalHeader(byte[] bytes) {
 169         for (byte[] possibleStart : POSSIBLE_STARTS) {
 170             int i = 0;
 171             for (byte b : possibleStart) {
 172                 if(bytes[i++] != b) {
 173                     break;
 174                 }
 175
 176                 if(i == possibleStart.length) {
 177                     return true;
 178                 }
 179             }
 180         }
 181
 182         return false;
 183     }
 184
 185     private String additionalHeaderToString(byte[] bytes) {
 186         return Charsets.UTF_8.decode(ByteBuffer.wrap(bytes)).toString();
 187     }
 188
 189     /**
 190      * @return Collection of NetconfMessages that were not hello, but were received during negotiation
 191      */
 192     public Iterable<NetconfMessage> getPostHelloNetconfMessages() {
 193         return nonHelloMessages;
 194     }
 195 }