bgp/parser-impl/src/main/java/org/opendaylight/protocol/bgp/parser/impl/message/BGPUpdateMessageParser.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.protocol.bgp.parser.impl.message;
   9
  10 import static java.util.Objects.requireNonNull;
  11
  12 import com.google.common.base.Preconditions;
  13 import io.netty.buffer.ByteBuf;
  14 import io.netty.buffer.Unpooled;
  15 import java.util.ArrayList;
  16 import java.util.List;
  17 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
  18 import org.opendaylight.protocol.bgp.parser.BGPError;
  19 import org.opendaylight.protocol.bgp.parser.BGPParsingException;
  20 import org.opendaylight.protocol.bgp.parser.BgpTableTypeImpl;
  21 import org.opendaylight.protocol.bgp.parser.impl.message.update.AsPathAttributeParser;
  22 import org.opendaylight.protocol.bgp.parser.impl.message.update.NextHopAttributeParser;
  23 import org.opendaylight.protocol.bgp.parser.impl.message.update.OriginAttributeParser;
  24 import org.opendaylight.protocol.bgp.parser.spi.AttributeRegistry;
  25 import org.opendaylight.protocol.bgp.parser.spi.MessageParser;
  26 import org.opendaylight.protocol.bgp.parser.spi.MessageSerializer;
  27 import org.opendaylight.protocol.bgp.parser.spi.MessageUtil;
  28 import org.opendaylight.protocol.bgp.parser.spi.MultiPathSupportUtil;
  29 import org.opendaylight.protocol.bgp.parser.spi.PathIdUtil;
  30 import org.opendaylight.protocol.bgp.parser.spi.PeerSpecificParserConstraint;
  31 import org.opendaylight.protocol.util.ByteBufWriteUtil;
  32 import org.opendaylight.protocol.util.Ipv4Util;
  33 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Prefix;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.PathId;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Update;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.UpdateBuilder;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.Attributes;
  38 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.Nlri;
  39 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.NlriBuilder;
  40 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.WithdrawnRoutes;
  41 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.WithdrawnRoutesBuilder;
  42 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev180329.Ipv4AddressFamily;
  43 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev180329.UnicastSubsequentAddressFamily;
  44 import org.opendaylight.yangtools.yang.binding.Notification;
  45 import org.slf4j.Logger;
  46 import org.slf4j.LoggerFactory;
  47
  48 /**
  49  * LENGTH fields, that denote the length of the fields with variable length, have fixed SIZE.
  50  *
  51  * @see <a href="http://tools.ietf.org/html/rfc4271#section-4.3">BGP-4 Update Message Format</a>
  52  */
  53 public final class BGPUpdateMessageParser implements MessageParser, MessageSerializer {
  54
  55     private static final Logger LOG = LoggerFactory.getLogger(BGPUpdateMessageParser.class);
  56
  57     public static final int TYPE = 2;
  58
  59     private static final int WITHDRAWN_ROUTES_LENGTH_SIZE = 2;
  60
  61     private static final int TOTAL_PATH_ATTR_LENGTH_SIZE = 2;
  62
  63     private final AttributeRegistry reg;
  64
  65     public BGPUpdateMessageParser(final AttributeRegistry reg) {
  66         this.reg = requireNonNull(reg);
  67     }
  68
  69     @Override
  70     public Update parseMessageBody(final ByteBuf buffer, final int messageLength) throws BGPDocumentedException {
  71         return parseMessageBody(buffer, messageLength, null);
  72     }
  73
  74     @Override
  75     public void serializeMessage(final Notification message, final ByteBuf bytes) {
  76         Preconditions.checkArgument(message instanceof Update, "Message needs to be of type Update");
  77         final Update update = (Update) message;
  78
  79         final ByteBuf messageBody = Unpooled.buffer();
  80         final List<WithdrawnRoutes> withdrawnRoutes = update.getWithdrawnRoutes();
  81         if (withdrawnRoutes != null) {
  82             final ByteBuf withdrawnRoutesBuf = Unpooled.buffer();
  83             withdrawnRoutes.forEach(withdrawnRoute -> writePathIdPrefix(withdrawnRoutesBuf, withdrawnRoute.getPathId(),
  84                     withdrawnRoute.getPrefix()));
  85             messageBody.writeShort(withdrawnRoutesBuf.writerIndex());
  86             messageBody.writeBytes(withdrawnRoutesBuf);
  87         } else {
  88             messageBody.writeZero(WITHDRAWN_ROUTES_LENGTH_SIZE);
  89         }
  90         if (update.getAttributes() != null) {
  91             final ByteBuf pathAttributesBuf = Unpooled.buffer();
  92             this.reg.serializeAttribute(update.getAttributes(), pathAttributesBuf);
  93             messageBody.writeShort(pathAttributesBuf.writerIndex());
  94             messageBody.writeBytes(pathAttributesBuf);
  95         } else {
  96             messageBody.writeZero(TOTAL_PATH_ATTR_LENGTH_SIZE);
  97         }
  98         final List<Nlri> nlris = update.getNlri();
  99         if (nlris != null) {
 100             nlris.forEach(nlri -> writePathIdPrefix(messageBody, nlri.getPathId(), nlri.getPrefix()));
 101         }
 102         MessageUtil.formatMessage(TYPE, messageBody, bytes);
 103     }
 104
 105     private void writePathIdPrefix(final ByteBuf byteBuf, final PathId pathId, final Ipv4Prefix ipv4Prefix) {
 106         PathIdUtil.writePathId(pathId, byteBuf);
 107         ByteBufWriteUtil.writeMinimalPrefix(ipv4Prefix, byteBuf);
 108     }
 109
 110     /**
 111      * Parse Update message from buffer.
 112      * Calls {@link #checkMandatoryAttributesPresence(Update)} to check for presence of mandatory attributes.
 113      *
 114      * @param buffer Encoded BGP message in ByteBuf
 115      * @param messageLength Length of the BGP message
 116      * @param constraint Peer specific constraints
 117      * @return Parsed Update message body
 118      */
 119     @Override
 120     public Update parseMessageBody(final ByteBuf buffer, final int messageLength,
 121             final PeerSpecificParserConstraint constraint) throws BGPDocumentedException {
 122         Preconditions.checkArgument(buffer != null && buffer.isReadable(),
 123                 "Buffer cannot be null or empty.");
 124
 125         final UpdateBuilder builder = new UpdateBuilder();
 126         final boolean isMultiPathSupported = MultiPathSupportUtil.isTableTypeSupported(constraint,
 127                 new BgpTableTypeImpl(Ipv4AddressFamily.class, UnicastSubsequentAddressFamily.class));
 128
 129         final int withdrawnRoutesLength = buffer.readUnsignedShort();
 130         if (withdrawnRoutesLength > 0) {
 131             final List<WithdrawnRoutes> withdrawnRoutes = new ArrayList<>();
 132             final ByteBuf withdrawnRoutesBuffer = buffer.readBytes(withdrawnRoutesLength);
 133             while (withdrawnRoutesBuffer.isReadable()) {
 134                 final WithdrawnRoutesBuilder withdrawnRoutesBuilder = new WithdrawnRoutesBuilder();
 135                 if (isMultiPathSupported) {
 136                     withdrawnRoutesBuilder.setPathId(PathIdUtil.readPathId(withdrawnRoutesBuffer));
 137                 }
 138                 withdrawnRoutesBuilder.setPrefix(Ipv4Util.prefixForByteBuf(withdrawnRoutesBuffer));
 139                 withdrawnRoutes.add(withdrawnRoutesBuilder.build());
 140             }
 141             builder.setWithdrawnRoutes(withdrawnRoutes);
 142         }
 143         final int totalPathAttrLength = buffer.readUnsignedShort();
 144
 145         if (withdrawnRoutesLength == 0 && totalPathAttrLength == 0) {
 146             return builder.build();
 147         }
 148         if (totalPathAttrLength > 0) {
 149             try {
 150                 final Attributes attributes
 151                         = this.reg.parseAttributes(buffer.readSlice(totalPathAttrLength), constraint);
 152                 builder.setAttributes(attributes);
 153             } catch (final RuntimeException | BGPParsingException e) {
 154                 // Catch everything else and turn it into a BGPDocumentedException
 155                 throw new BGPDocumentedException("Could not parse BGP attributes.", BGPError.MALFORMED_ATTR_LIST, e);
 156             }
 157         }
 158         final List<Nlri> nlri = new ArrayList<>();
 159         while (buffer.isReadable()) {
 160             final NlriBuilder nlriBuilder = new NlriBuilder();
 161             if (isMultiPathSupported) {
 162                 nlriBuilder.setPathId(PathIdUtil.readPathId(buffer));
 163             }
 164             nlriBuilder.setPrefix(Ipv4Util.prefixForByteBuf(buffer));
 165             nlri.add(nlriBuilder.build());
 166         }
 167         if (!nlri.isEmpty()) {
 168             builder.setNlri(nlri);
 169         }
 170         final Update msg = builder.build();
 171         checkMandatoryAttributesPresence(msg);
 172         LOG.debug("BGP Update message was parsed {}.", msg);
 173         return msg;
 174     }
 175
 176     /**
 177      * Check for presence of well known mandatory path attributes
 178      * ORIGIN, AS_PATH and NEXT_HOP in Update message
 179      *
 180      * @param message Update message
 181      * @throws BGPDocumentedException
 182      */
 183     private static void checkMandatoryAttributesPresence(final Update message) throws BGPDocumentedException {
 184         requireNonNull(message, "Update message cannot be null");
 185
 186         final Attributes attrs = message.getAttributes();
 187
 188         if (message.getNlri() != null) {
 189             if (attrs == null || attrs.getCNextHop() == null) {
 190                 throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "NEXT_HOP",
 191                         BGPError.WELL_KNOWN_ATTR_MISSING,
 192                         new byte[] { NextHopAttributeParser.TYPE });
 193             }
 194         }
 195
 196         if (MessageUtil.isAnyNlriPresent(message)) {
 197             if (attrs == null || attrs.getOrigin() == null) {
 198                 throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "ORIGIN",
 199                         BGPError.WELL_KNOWN_ATTR_MISSING,
 200                         new byte[] { OriginAttributeParser.TYPE });
 201             }
 202
 203             if (attrs.getAsPath() == null) {
 204                 throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "AS_PATH",
 205                         BGPError.WELL_KNOWN_ATTR_MISSING,
 206                         new byte[] { AsPathAttributeParser.TYPE });
 207             }
 208         }
 209     }
 210 }