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.base.Preconditions;
  11 import com.google.common.collect.Lists;
  12 import io.netty.buffer.ByteBuf;
  13 import io.netty.buffer.ByteBufUtil;
  14 import io.netty.channel.ChannelHandlerContext;
  15 import io.netty.handler.codec.ByteToMessageDecoder;
  16
  17 import java.io.ByteArrayInputStream;
  18 import java.io.IOException;
  19 import java.nio.ByteBuffer;
  20 import java.util.Arrays;
  21 import java.util.List;
  22
  23 import org.opendaylight.controller.netconf.api.NetconfDocumentedException;
  24 import org.opendaylight.controller.netconf.api.NetconfMessage;
  25 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  26 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessageAdditionalHeader;
  27 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  28 import org.slf4j.Logger;
  29 import org.slf4j.LoggerFactory;
  30 import org.w3c.dom.Document;
  31
  32 import com.google.common.annotations.VisibleForTesting;
  33 import com.google.common.base.Charsets;
  34 import com.google.common.collect.ImmutableList;
  35 import org.xml.sax.SAXException;
  36
  37 /**
  38  * Customized NetconfXMLToMessageDecoder that reads additional header with
  39  * session metadata from
  40  * {@link org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage}
  41  *
  42  *
  43  * This handler should be replaced in pipeline by regular message handler as last step of negotiation.
  44  * It serves as a message barrier and halts all non-hello netconf messages.
  45  * Netconf messages after hello should be processed once the negotiation succeeded.
  46  *
  47  */
  48 public final class NetconfXMLToHelloMessageDecoder extends ByteToMessageDecoder {
  49     private static final Logger LOG = LoggerFactory.getLogger(NetconfXMLToHelloMessageDecoder.class);
  50
  51     private static final List<byte[]> POSSIBLE_ENDS = ImmutableList.of(
  52             new byte[] { ']', '\n' },
  53             new byte[] { ']', '\r', '\n' });
  54     private static final List<byte[]> POSSIBLE_STARTS = ImmutableList.of(
  55             new byte[] { '[' },
  56             new byte[] { '\r', '\n', '[' },
  57             new byte[] { '\n', '[' });
  58
  59     // State variables do not have to by synchronized
  60     // Netty uses always the same (1) thread per pipeline
  61     // We use instance of this per pipeline
  62     private List<NetconfMessage> nonHelloMessages = Lists.newArrayList();
  63     private boolean helloReceived = false;
  64
  65     @Override
  66     @VisibleForTesting
  67     public void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws IOException, SAXException, NetconfDocumentedException {
  68         if (in.readableBytes() == 0) {
  69             LOG.debug("No more content in incoming buffer.");
  70             return;
  71         }
  72
  73         in.markReaderIndex();
  74         try {
  75             LOG.trace("Received to decode: {}", ByteBufUtil.hexDump(in));
  76             byte[] bytes = new byte[in.readableBytes()];
  77             in.readBytes(bytes);
  78
  79             logMessage(bytes);
  80
  81             // Extract bytes containing header with additional metadata
  82             String additionalHeader = null;
  83             if (startsWithAdditionalHeader(bytes)) {
  84                 // Auth information containing username, ip address... extracted for monitoring
  85                 int endOfAuthHeader = getAdditionalHeaderEndIndex(bytes);
  86                 if (endOfAuthHeader > -1) {
  87                     byte[] additionalHeaderBytes = Arrays.copyOfRange(bytes, 0, endOfAuthHeader + 2);
  88                     additionalHeader = additionalHeaderToString(additionalHeaderBytes);
  89                     bytes = Arrays.copyOfRange(bytes, endOfAuthHeader + 2, bytes.length);
  90                 }
  91             }
  92
  93             Document doc = XmlUtil.readXmlToDocument(new ByteArrayInputStream(bytes));
  94
  95             final NetconfMessage message = getNetconfMessage(additionalHeader, doc);
  96             if (message instanceof NetconfHelloMessage) {
  97                 Preconditions.checkState(helloReceived == false,
  98                         "Multiple hello messages received, unexpected hello: %s",
  99                         XmlUtil.toString(message.getDocument()));
 100                 out.add(message);
 101                 helloReceived = true;
 102             // Non hello message, suspend the message and insert into cache
 103             } else {
 104                 Preconditions.checkState(helloReceived, "Hello message not received, instead received: %s",
 105                         XmlUtil.toString(message.getDocument()));
 106                 LOG.debug("Netconf message received during negotiation, caching {}",
 107                         XmlUtil.toString(message.getDocument()));
 108                 nonHelloMessages.add(message);
 109             }
 110         } finally {
 111             in.discardReadBytes();
 112         }
 113     }
 114
 115     private NetconfMessage getNetconfMessage(final String additionalHeader, final Document doc) throws NetconfDocumentedException {
 116         NetconfMessage msg = new NetconfMessage(doc);
 117         if(NetconfHelloMessage.isHelloMessage(msg)) {
 118             if (additionalHeader != null) {
 119                 return new NetconfHelloMessage(doc, NetconfHelloMessageAdditionalHeader.fromString(additionalHeader));
 120             } else {
 121                 return new NetconfHelloMessage(doc);
 122             }
 123         }
 124
 125         return msg;
 126     }
 127
 128     private int getAdditionalHeaderEndIndex(byte[] bytes) {
 129         for (byte[] possibleEnd : POSSIBLE_ENDS) {
 130             int idx = findByteSequence(bytes, possibleEnd);
 131
 132             if (idx != -1) {
 133                 return idx;
 134             }
 135         }
 136
 137         return -1;
 138     }
 139
 140     private static int findByteSequence(final byte[] bytes, final byte[] sequence) {
 141         if (bytes.length < sequence.length) {
 142             throw new IllegalArgumentException("Sequence to be found is longer than the given byte array.");
 143         }
 144         if (bytes.length == sequence.length) {
 145             if (Arrays.equals(bytes, sequence)) {
 146                 return 0;
 147             } else {
 148                 return -1;
 149             }
 150         }
 151         int j = 0;
 152         for (int i = 0; i < bytes.length; i++) {
 153             if (bytes[i] == sequence[j]) {
 154                 j++;
 155                 if (j == sequence.length) {
 156                     return i - j + 1;
 157                 }
 158             } else {
 159                 j = 0;
 160             }
 161         }
 162         return -1;
 163     }
 164
 165
 166     private void logMessage(byte[] bytes) {
 167         String s = Charsets.UTF_8.decode(ByteBuffer.wrap(bytes)).toString();
 168         LOG.debug("Parsing message \n{}", s);
 169     }
 170
 171     private boolean startsWithAdditionalHeader(byte[] bytes) {
 172         for (byte[] possibleStart : POSSIBLE_STARTS) {
 173             int i = 0;
 174             for (byte b : possibleStart) {
 175                 if(bytes[i++] != b) {
 176                     break;
 177                 }
 178
 179                 if(i == possibleStart.length) {
 180                     return true;
 181                 }
 182             }
 183         }
 184
 185         return false;
 186     }
 187
 188     private String additionalHeaderToString(byte[] bytes) {
 189         return Charsets.UTF_8.decode(ByteBuffer.wrap(bytes)).toString();
 190     }
 191
 192     /**
 193      * @return Collection of NetconfMessages that were not hello, but were received during negotiation
 194      */
 195     public Iterable<NetconfMessage> getPostHelloNetconfMessages() {
 196         return nonHelloMessages;
 197     }
 198 }