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