netconf/netconf-netty-util/src/main/java/org/opendaylight/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.netconf.nettyutil.handler;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Preconditions;
  12 import com.google.common.collect.ImmutableList;
  13 import io.netty.buffer.ByteBuf;
  14 import io.netty.buffer.ByteBufUtil;
  15 import io.netty.channel.ChannelHandlerContext;
  16 import io.netty.handler.codec.ByteToMessageDecoder;
  17 import java.io.ByteArrayInputStream;
  18 import java.io.IOException;
  19 import java.nio.ByteBuffer;
  20 import java.nio.charset.StandardCharsets;
  21 import java.util.ArrayList;
  22 import java.util.Arrays;
  23 import java.util.List;
  24 import org.opendaylight.netconf.api.messages.HelloMessage;
  25 import org.opendaylight.netconf.api.messages.NetconfHelloMessageAdditionalHeader;
  26 import org.opendaylight.netconf.api.messages.NetconfMessage;
  27 import org.opendaylight.netconf.api.xml.XmlUtil;
  28 import org.slf4j.Logger;
  29 import org.slf4j.LoggerFactory;
  30 import org.w3c.dom.Document;
  31 import org.xml.sax.SAXException;
  32
  33 /**
  34  * Customized NetconfXMLToMessageDecoder that reads additional header with
  35  * session metadata from
  36  * {@link HelloMessage}*
  37  * This handler should be replaced in pipeline by regular message handler as last step of negotiation.
  38  * It serves as a message barrier and halts all non-hello netconf messages.
  39  * Netconf messages after hello should be processed once the negotiation succeeded.
  40  *
  41  */
  42 public final class NetconfXMLToHelloMessageDecoder extends ByteToMessageDecoder {
  43     private static final Logger LOG = LoggerFactory.getLogger(NetconfXMLToHelloMessageDecoder.class);
  44
  45     private static final List<byte[]> POSSIBLE_ENDS = ImmutableList.of(
  46             new byte[] { ']', '\n' },
  47             new byte[] { ']', '\r', '\n' });
  48     private static final List<byte[]> POSSIBLE_STARTS = ImmutableList.of(
  49             new byte[] { '[' },
  50             new byte[] { '\r', '\n', '[' },
  51             new byte[] { '\n', '[' });
  52
  53     // State variables do not have to by synchronized
  54     // Netty uses always the same (1) thread per pipeline
  55     // We use instance of this per pipeline
  56     private final List<NetconfMessage> nonHelloMessages = new ArrayList<>();
  57     private boolean helloReceived = false;
  58
  59     @Override
  60     @VisibleForTesting
  61     public void decode(final ChannelHandlerContext ctx, final ByteBuf in, final List<Object> out)
  62             throws IOException, SAXException {
  63         if (in.readableBytes() == 0) {
  64             LOG.debug("No more content in incoming buffer.");
  65             return;
  66         }
  67
  68         in.markReaderIndex();
  69         try {
  70             if (LOG.isTraceEnabled()) {
  71                 LOG.trace("Received to decode: {}", ByteBufUtil.hexDump(in));
  72             }
  73
  74             byte[] bytes = new byte[in.readableBytes()];
  75             in.readBytes(bytes);
  76
  77             logMessage(bytes);
  78
  79             // Extract bytes containing header with additional metadata
  80             String additionalHeader = null;
  81             if (startsWithAdditionalHeader(bytes)) {
  82                 // Auth information containing username, ip address... extracted for monitoring
  83                 int endOfAuthHeader = getAdditionalHeaderEndIndex(bytes);
  84                 if (endOfAuthHeader > -1) {
  85                     byte[] additionalHeaderBytes = Arrays.copyOfRange(bytes, 0, endOfAuthHeader);
  86                     additionalHeader = additionalHeaderToString(additionalHeaderBytes);
  87                     bytes = Arrays.copyOfRange(bytes, endOfAuthHeader, bytes.length);
  88                 }
  89             }
  90
  91             Document doc = XmlUtil.readXmlToDocument(new ByteArrayInputStream(bytes));
  92
  93             final NetconfMessage message = getNetconfMessage(additionalHeader, doc);
  94             if (message instanceof HelloMessage) {
  95                 Preconditions.checkState(!helloReceived,
  96                         "Multiple hello messages received, unexpected hello: %s", message);
  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", message);
 102                 LOG.debug("Netconf message received during negotiation, caching {}", message);
 103                 nonHelloMessages.add(message);
 104             }
 105         } finally {
 106             in.discardReadBytes();
 107         }
 108     }
 109
 110     private static NetconfMessage getNetconfMessage(final String additionalHeader, final Document doc) {
 111         NetconfMessage msg = new NetconfMessage(doc);
 112         if (HelloMessage.isHelloMessage(msg)) {
 113             if (additionalHeader != null) {
 114                 return new HelloMessage(doc, NetconfHelloMessageAdditionalHeader.fromString(additionalHeader));
 115             } else {
 116                 return new HelloMessage(doc);
 117             }
 118         }
 119
 120         return msg;
 121     }
 122
 123     private static int getAdditionalHeaderEndIndex(final byte[] bytes) {
 124         for (byte[] possibleEnd : POSSIBLE_ENDS) {
 125             int idx = findByteSequence(bytes, possibleEnd);
 126
 127             if (idx != -1) {
 128                 return idx + possibleEnd.length;
 129             }
 130         }
 131
 132         return -1;
 133     }
 134
 135     private static int findByteSequence(final byte[] bytes, final byte[] sequence) {
 136         if (bytes.length < sequence.length) {
 137             throw new IllegalArgumentException("Sequence to be found is longer than the given byte array.");
 138         }
 139         if (bytes.length == sequence.length) {
 140             if (Arrays.equals(bytes, sequence)) {
 141                 return 0;
 142             } else {
 143                 return -1;
 144             }
 145         }
 146         int index = 0;
 147         for (int i = 0; i < bytes.length; i++) {
 148             if (bytes[i] == sequence[index]) {
 149                 index++;
 150                 if (index == sequence.length) {
 151                     return i - index + 1;
 152                 }
 153             } else {
 154                 index = 0;
 155             }
 156         }
 157         return -1;
 158     }
 159
 160     private static void logMessage(final byte[] bytes) {
 161         if (LOG.isDebugEnabled()) {
 162             String string = StandardCharsets.UTF_8.decode(ByteBuffer.wrap(bytes)).toString();
 163             LOG.debug("Parsing message \n{}", string);
 164         }
 165     }
 166
 167     private static boolean startsWithAdditionalHeader(final byte[] bytes) {
 168         for (byte[] possibleStart : POSSIBLE_STARTS) {
 169             int index = 0;
 170             for (byte b : possibleStart) {
 171                 if (bytes[index++] != b) {
 172                     break;
 173                 }
 174
 175                 if (index == possibleStart.length) {
 176                     return true;
 177                 }
 178             }
 179         }
 180
 181         return false;
 182     }
 183
 184     private static String additionalHeaderToString(final byte[] bytes) {
 185         return StandardCharsets.UTF_8.decode(ByteBuffer.wrap(bytes)).toString();
 186     }
 187
 188     /**
 189      * Get netconf messages received during negotiation.
 190      *
 191      * @return Collection of NetconfMessages that were not hello, but were received during negotiation.
 192      */
 193     public Iterable<NetconfMessage> getPostHelloNetconfMessages() {
 194         return nonHelloMessages;
 195     }
 196 }