2 * Copyright (c) 2013 Cisco Systems, Inc. and others. All rights reserved.
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
8 package org.opendaylight.protocol.bgp.parser.impl.message;
10 import static java.util.Objects.requireNonNull;
12 import com.google.common.base.Preconditions;
13 import com.google.common.collect.ImmutableList;
14 import com.google.common.collect.Streams;
15 import io.netty.buffer.ByteBuf;
16 import io.netty.buffer.Unpooled;
17 import java.util.ArrayList;
18 import java.util.List;
19 import java.util.Optional;
20 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
21 import org.opendaylight.protocol.bgp.parser.BGPError;
22 import org.opendaylight.protocol.bgp.parser.BGPParsingException;
23 import org.opendaylight.protocol.bgp.parser.BGPTreatAsWithdrawException;
24 import org.opendaylight.protocol.bgp.parser.BgpTableTypeImpl;
25 import org.opendaylight.protocol.bgp.parser.impl.message.update.AsPathAttributeParser;
26 import org.opendaylight.protocol.bgp.parser.impl.message.update.NextHopAttributeParser;
27 import org.opendaylight.protocol.bgp.parser.impl.message.update.OriginAttributeParser;
28 import org.opendaylight.protocol.bgp.parser.spi.AttributeRegistry;
29 import org.opendaylight.protocol.bgp.parser.spi.MessageParser;
30 import org.opendaylight.protocol.bgp.parser.spi.MessageSerializer;
31 import org.opendaylight.protocol.bgp.parser.spi.MessageUtil;
32 import org.opendaylight.protocol.bgp.parser.spi.MultiPathSupportUtil;
33 import org.opendaylight.protocol.bgp.parser.spi.NlriRegistry;
34 import org.opendaylight.protocol.bgp.parser.spi.ParsedAttributes;
35 import org.opendaylight.protocol.bgp.parser.spi.PathIdUtil;
36 import org.opendaylight.protocol.bgp.parser.spi.PeerSpecificParserConstraint;
37 import org.opendaylight.protocol.bgp.parser.spi.RevisedErrorHandling;
38 import org.opendaylight.protocol.util.ByteBufWriteUtil;
39 import org.opendaylight.protocol.util.Ipv4Util;
40 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Prefix;
41 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.PathId;
42 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Update;
43 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.UpdateBuilder;
44 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.Attributes;
45 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.AttributesBuilder;
46 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.Nlri;
47 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.NlriBuilder;
48 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.WithdrawnRoutes;
49 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.update.message.WithdrawnRoutesBuilder;
50 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev180329.Attributes1;
51 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev180329.Attributes2;
52 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev180329.Attributes2Builder;
53 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev180329.mp.capabilities.graceful.restart.capability.TablesKey;
54 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev180329.update.attributes.MpReachNlri;
55 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev180329.update.attributes.MpUnreachNlri;
56 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev180329.Ipv4AddressFamily;
57 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev180329.UnicastSubsequentAddressFamily;
58 import org.opendaylight.yangtools.yang.binding.Notification;
59 import org.slf4j.Logger;
60 import org.slf4j.LoggerFactory;
63 * LENGTH fields, that denote the length of the fields with variable length, have fixed SIZE.
65 * @see <a href="http://tools.ietf.org/html/rfc4271#section-4.3">BGP-4 Update Message Format</a>
67 public final class BGPUpdateMessageParser implements MessageParser, MessageSerializer {
69 private static final Logger LOG = LoggerFactory.getLogger(BGPUpdateMessageParser.class);
71 public static final int TYPE = 2;
73 private final AttributeRegistry attrReg;
75 private final NlriRegistry nlriReg;
77 public BGPUpdateMessageParser(final AttributeRegistry attrReg, final NlriRegistry nlriReg) {
78 this.attrReg = requireNonNull(attrReg);
79 this.nlriReg = requireNonNull(nlriReg);
83 public void serializeMessage(final Notification message, final ByteBuf bytes) {
84 Preconditions.checkArgument(message instanceof Update, "Message needs to be of type Update");
85 final Update update = (Update) message;
87 final ByteBuf messageBody = Unpooled.buffer();
88 final List<WithdrawnRoutes> withdrawnRoutes = update.getWithdrawnRoutes();
89 if (withdrawnRoutes != null) {
90 final ByteBuf withdrawnRoutesBuf = Unpooled.buffer();
91 withdrawnRoutes.forEach(withdrawnRoute -> writePathIdPrefix(withdrawnRoutesBuf, withdrawnRoute.getPathId(),
92 withdrawnRoute.getPrefix()));
93 messageBody.writeShort(withdrawnRoutesBuf.writerIndex());
94 messageBody.writeBytes(withdrawnRoutesBuf);
96 messageBody.writeShort(0);
98 if (update.getAttributes() != null) {
99 final ByteBuf pathAttributesBuf = Unpooled.buffer();
100 this.attrReg.serializeAttribute(update.getAttributes(), pathAttributesBuf);
101 messageBody.writeShort(pathAttributesBuf.writerIndex());
102 messageBody.writeBytes(pathAttributesBuf);
104 messageBody.writeShort(0);
106 final List<Nlri> nlris = update.getNlri();
108 nlris.forEach(nlri -> writePathIdPrefix(messageBody, nlri.getPathId(), nlri.getPrefix()));
110 MessageUtil.formatMessage(TYPE, messageBody, bytes);
113 private static void writePathIdPrefix(final ByteBuf byteBuf, final PathId pathId, final Ipv4Prefix ipv4Prefix) {
114 PathIdUtil.writePathId(pathId, byteBuf);
115 ByteBufWriteUtil.writeMinimalPrefix(ipv4Prefix, byteBuf);
119 * Parse Update message from buffer. Calls {@link #checkMandatoryAttributesPresence(Update, RevisedErrorHandling)}
120 * to check for presence of mandatory attributes.
122 * @param buffer Encoded BGP message in ByteBuf
123 * @param messageLength Length of the BGP message
124 * @param constraint Peer specific constraints
125 * @return Parsed Update message body
128 public Update parseMessageBody(final ByteBuf buffer, final int messageLength,
129 final PeerSpecificParserConstraint constraint) throws BGPDocumentedException {
130 Preconditions.checkArgument(buffer != null && buffer.isReadable(),
131 "Buffer cannot be null or empty.");
133 final UpdateBuilder builder = new UpdateBuilder();
134 final boolean isMultiPathSupported = MultiPathSupportUtil.isTableTypeSupported(constraint,
135 new BgpTableTypeImpl(Ipv4AddressFamily.class, UnicastSubsequentAddressFamily.class));
136 final RevisedErrorHandling errorHandling = RevisedErrorHandling.from(constraint);
138 final int withdrawnRoutesLength = buffer.readUnsignedShort();
139 if (withdrawnRoutesLength > 0) {
140 final List<WithdrawnRoutes> withdrawnRoutes = new ArrayList<>();
141 final ByteBuf withdrawnRoutesBuffer = buffer.readBytes(withdrawnRoutesLength);
142 while (withdrawnRoutesBuffer.isReadable()) {
143 final WithdrawnRoutesBuilder withdrawnRoutesBuilder = new WithdrawnRoutesBuilder();
144 if (isMultiPathSupported) {
145 withdrawnRoutesBuilder.setPathId(PathIdUtil.readPathId(withdrawnRoutesBuffer));
147 withdrawnRoutesBuilder.setPrefix(readPrefix(withdrawnRoutesBuffer, errorHandling, "Withdrawn Routes"));
148 withdrawnRoutes.add(withdrawnRoutesBuilder.build());
150 withdrawnRoutesBuffer.release();
151 builder.setWithdrawnRoutes(withdrawnRoutes);
153 final int totalPathAttrLength = buffer.readUnsignedShort();
154 if (withdrawnRoutesLength == 0 && totalPathAttrLength == 0) {
155 return builder.build();
158 Optional<BGPTreatAsWithdrawException> withdrawCauseOpt;
159 if (totalPathAttrLength > 0) {
160 final ParsedAttributes attributes = parseAttributes(buffer, totalPathAttrLength, constraint);
161 builder.setAttributes(attributes.getAttributes());
162 withdrawCauseOpt = attributes.getWithdrawCause();
164 withdrawCauseOpt = Optional.empty();
167 final List<Nlri> nlri = new ArrayList<>();
168 while (buffer.isReadable()) {
169 final NlriBuilder nlriBuilder = new NlriBuilder();
170 if (isMultiPathSupported) {
171 nlriBuilder.setPathId(PathIdUtil.readPathId(buffer));
173 nlriBuilder.setPrefix(readPrefix(buffer, errorHandling, "NLRI"));
174 nlri.add(nlriBuilder.build());
176 if (!nlri.isEmpty()) {
177 builder.setNlri(nlri);
181 checkMandatoryAttributesPresence(builder.build(), errorHandling);
182 } catch (BGPTreatAsWithdrawException e) {
183 LOG.debug("Well-known mandatory attributes missing", e);
184 if (withdrawCauseOpt.isPresent()) {
185 final BGPTreatAsWithdrawException exception = withdrawCauseOpt.get();
186 exception.addSuppressed(e);
187 withdrawCauseOpt = Optional.of(exception);
189 withdrawCauseOpt = Optional.of(e);
193 Update msg = builder.build();
194 if (withdrawCauseOpt.isPresent()) {
195 // Attempt to apply treat-as-withdraw
196 msg = withdrawUpdate(msg, errorHandling, withdrawCauseOpt.get());
199 LOG.debug("BGP Update message was parsed {}.", msg);
203 @SuppressWarnings("checkstyle:illegalCatch")
204 private ParsedAttributes parseAttributes(final ByteBuf buffer, final int totalPathAttrLength,
205 final PeerSpecificParserConstraint constraint) throws BGPDocumentedException {
207 return attrReg.parseAttributes(buffer.readSlice(totalPathAttrLength), constraint);
208 } catch (final RuntimeException | BGPParsingException e) {
209 // Catch everything else and turn it into a BGPDocumentedException
210 throw new BGPDocumentedException("Could not parse BGP attributes.", BGPError.MALFORMED_ATTR_LIST, e);
214 private static Ipv4Prefix readPrefix(final ByteBuf buf, final RevisedErrorHandling errorHandling,
215 final String fieldName) throws BGPDocumentedException {
216 final int prefixLength = buf.readUnsignedByte();
217 if (errorHandling != RevisedErrorHandling.NONE) {
218 // https://tools.ietf.org/html/rfc7606#section-5.3
219 if (prefixLength > 32) {
220 throw new BGPDocumentedException(fieldName + " length " + prefixLength + " exceeds 32 bytes",
221 BGPError.ATTR_LENGTH_ERROR);
223 if (prefixLength > buf.readableBytes() * 8) {
224 throw new BGPDocumentedException(fieldName + " length " + prefixLength
225 + " exceeds unconsumed field space", BGPError.ATTR_LENGTH_ERROR);
229 return Ipv4Util.prefixForByteBuf(buf, prefixLength);
233 * Check for presence of well known mandatory path attributes ORIGIN, AS_PATH and NEXT_HOP in Update message.
235 * @param message Update message
236 * @param errorHandling Error handling type
238 private static void checkMandatoryAttributesPresence(final Update message,
239 final RevisedErrorHandling errorHandling) throws BGPDocumentedException, BGPTreatAsWithdrawException {
240 requireNonNull(message, "Update message cannot be null");
242 final Attributes attrs = message.getAttributes();
243 if (message.getNlri() != null && (attrs == null || attrs.getCNextHop() == null)) {
244 throw reportMissingAttribute(errorHandling, "NEXT_HOP", NextHopAttributeParser.TYPE);
247 if (MessageUtil.isAnyNlriPresent(message)) {
248 if (attrs == null || attrs.getOrigin() == null) {
249 throw reportMissingAttribute(errorHandling, "ORIGIN", OriginAttributeParser.TYPE);
251 if (attrs.getAsPath() == null) {
252 throw reportMissingAttribute(errorHandling, "AS_PATH", AsPathAttributeParser.TYPE);
257 private static BGPDocumentedException reportMissingAttribute(final RevisedErrorHandling errorHandling,
258 final String attrName, final int attrType) throws BGPDocumentedException, BGPTreatAsWithdrawException {
259 return errorHandling.reportError(BGPError.WELL_KNOWN_ATTR_MISSING, new byte[] { (byte) attrType },
260 "Well known mandatory attribute missing: %s", attrName);
263 private Update withdrawUpdate(final Update parsed, final RevisedErrorHandling errorHandling,
264 final BGPTreatAsWithdrawException withdrawCause) throws BGPDocumentedException {
265 if (errorHandling == RevisedErrorHandling.NONE) {
266 throw new BGPDocumentedException(withdrawCause);
269 // TODO: additional checks as per RFC7606 section 5.2
271 LOG.debug("Converting BGP Update message {} to withdraw", parsed, withdrawCause);
272 final UpdateBuilder builder = new UpdateBuilder();
274 final List<Nlri> nlris = parsed.getNlri();
275 final List<WithdrawnRoutes> withdrawn;
276 if (nlris != null && !nlris.isEmpty()) {
277 withdrawn = Streams.concat(parsed.nonnullWithdrawnRoutes().stream(),
278 nlris.stream().map(nlri -> new WithdrawnRoutesBuilder(nlri).build()))
279 .collect(ImmutableList.toImmutableList());
281 withdrawn = parsed.getWithdrawnRoutes();
283 builder.setWithdrawnRoutes(withdrawn);
285 final Attributes attributes = parsed.getAttributes();
286 if (attributes != null) {
287 builder.setAttributes(withdrawAttributes(attributes, withdrawCause));
290 return builder.build();
293 private Attributes withdrawAttributes(final Attributes parsed,
294 final BGPTreatAsWithdrawException withdrawCause) throws BGPDocumentedException {
295 final AttributesBuilder builder = new AttributesBuilder();
296 final MpReachNlri mpReachNlri = getMpReach(parsed);
297 if (mpReachNlri == null) {
298 // No MP_REACH attribute, just reuse MP_UNREACH if it is present.
299 builder.addAugmentation(Attributes2.class, parsed.augmentation(Attributes2.class));
300 return builder.build();
303 final MpUnreachNlri unreachNlri = getMpUnreach(parsed);
304 if (unreachNlri != null) {
305 final TablesKey reachKey = new TablesKey(mpReachNlri.getAfi(), mpReachNlri.getSafi());
306 final TablesKey unreachKey = new TablesKey(unreachNlri.getAfi(), unreachNlri.getSafi());
307 if (!reachKey.equals(unreachKey)) {
308 LOG.warn("Unexpected mismatch between MP_REACH ({}) and MP_UNREACH ({})", reachKey, unreachKey,
310 throw new BGPDocumentedException(withdrawCause);
314 final MpUnreachNlri converted = this.nlriReg.convertMpReachToMpUnReach(mpReachNlri, unreachNlri)
316 LOG.warn("Could not convert attributes {} to withdraw attributes", parsed, withdrawCause);
317 return new BGPDocumentedException(withdrawCause);
320 builder.addAugmentation(Attributes2.class, new Attributes2Builder().setMpUnreachNlri(converted).build());
321 return builder.build();
324 private static MpReachNlri getMpReach(final Attributes attrs) {
325 final Attributes1 reachAttr = attrs.augmentation(Attributes1.class);
326 return reachAttr == null ? null : reachAttr.getMpReachNlri();
329 private static MpUnreachNlri getMpUnreach(final Attributes attrs) {
330 final Attributes2 unreachAttr = attrs.augmentation(Attributes2.class);
331 return unreachAttr == null ? null : unreachAttr.getMpUnreachNlri();