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;
11 import static java.util.Objects.requireNonNull;
13 import com.google.common.base.Preconditions;
14 import io.netty.buffer.ByteBuf;
15 import io.netty.buffer.Unpooled;
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.impl.message.update.AsPathAttributeParser;
21 import org.opendaylight.protocol.bgp.parser.impl.message.update.NextHopAttributeParser;
22 import org.opendaylight.protocol.bgp.parser.impl.message.update.OriginAttributeParser;
23 import org.opendaylight.protocol.bgp.parser.spi.AttributeRegistry;
24 import org.opendaylight.protocol.bgp.parser.spi.MessageParser;
25 import org.opendaylight.protocol.bgp.parser.spi.MessageSerializer;
26 import org.opendaylight.protocol.bgp.parser.spi.MessageUtil;
27 import org.opendaylight.protocol.bgp.parser.spi.PeerSpecificParserConstraint;
28 import org.opendaylight.protocol.util.ByteArray;
29 import org.opendaylight.protocol.util.ByteBufWriteUtil;
30 import org.opendaylight.protocol.util.Ipv4Util;
31 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Prefix;
32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Update;
33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.UpdateBuilder;
34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.Attributes;
35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.update.message.Nlri;
36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.update.message.NlriBuilder;
37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.update.message.WithdrawnRoutes;
38 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.update.message.WithdrawnRoutesBuilder;
39 import org.opendaylight.yangtools.yang.binding.Notification;
40 import org.slf4j.Logger;
41 import org.slf4j.LoggerFactory;
44 * LENGTH fields, that denote the length of the fields with variable length, have fixed SIZE.
46 * @see <a href="http://tools.ietf.org/html/rfc4271#section-4.3">BGP-4 Update Message Format</a>
48 public final class BGPUpdateMessageParser implements MessageParser, MessageSerializer {
50 private static final Logger LOG = LoggerFactory.getLogger(BGPUpdateMessageParser.class);
52 public static final int TYPE = 2;
54 private static final int WITHDRAWN_ROUTES_LENGTH_SIZE = 2;
56 private static final int TOTAL_PATH_ATTR_LENGTH_SIZE = 2;
58 private final AttributeRegistry reg;
60 public BGPUpdateMessageParser(final AttributeRegistry reg) {
61 this.reg = requireNonNull(reg);
65 public Update parseMessageBody(final ByteBuf buffer, final int messageLength) throws BGPDocumentedException {
66 return parseMessageBody(buffer, messageLength, null);
70 public void serializeMessage(final Notification message, final ByteBuf bytes) {
71 Preconditions.checkArgument(message instanceof Update, "Message needs to be of type Update");
72 final Update update = (Update) message;
74 final ByteBuf messageBody = Unpooled.buffer();
75 final WithdrawnRoutes withdrawnRoutes = update.getWithdrawnRoutes();
76 if (withdrawnRoutes != null) {
77 final ByteBuf withdrawnRoutesBuf = Unpooled.buffer();
78 for (final Ipv4Prefix prefix : withdrawnRoutes.getWithdrawnRoutes()) {
79 ByteBufWriteUtil.writeMinimalPrefix(prefix, withdrawnRoutesBuf);
81 messageBody.writeShort(withdrawnRoutesBuf.writerIndex());
82 messageBody.writeBytes(withdrawnRoutesBuf);
84 messageBody.writeZero(WITHDRAWN_ROUTES_LENGTH_SIZE);
86 if (update.getAttributes() != null) {
87 final ByteBuf pathAttributesBuf = Unpooled.buffer();
88 this.reg.serializeAttribute(update.getAttributes(), pathAttributesBuf);
89 messageBody.writeShort(pathAttributesBuf.writerIndex());
90 messageBody.writeBytes(pathAttributesBuf);
92 messageBody.writeZero(TOTAL_PATH_ATTR_LENGTH_SIZE);
94 final Nlri nlri = update.getNlri();
95 if (nlri != null && nlri.getNlri() !=null) {
96 for (final Ipv4Prefix prefix : nlri.getNlri()) {
97 ByteBufWriteUtil.writeMinimalPrefix(prefix, messageBody);
100 MessageUtil.formatMessage(TYPE, messageBody, bytes);
104 * Parse Update message from buffer.
105 * Calls {@link #checkMandatoryAttributesPresence(Update)} to check for presence of mandatory attributes.
107 * @param buffer Encoded BGP message in ByteBuf
108 * @param messageLength Length of the BGP message
109 * @param constraint Peer specific constraints
110 * @return Parsed Update message body
111 * @throws BGPDocumentedException
114 public Update parseMessageBody(final ByteBuf buffer, final int messageLength, final PeerSpecificParserConstraint constraint)
115 throws BGPDocumentedException {
116 Preconditions.checkArgument(buffer != null && buffer.isReadable(), "Buffer cannot be null or empty.");
118 final UpdateBuilder builder = new UpdateBuilder();
120 final int withdrawnRoutesLength = buffer.readUnsignedShort();
121 if (withdrawnRoutesLength > 0) {
122 // TODO handle NLRI with multiple paths - requires modified yang data model
123 final List<Ipv4Prefix> withdrawnRoutes = Ipv4Util.prefixListForBytes(ByteArray.readBytes(buffer, withdrawnRoutesLength));
124 builder.setWithdrawnRoutes(new WithdrawnRoutesBuilder().setWithdrawnRoutes(withdrawnRoutes).build());
126 final int totalPathAttrLength = buffer.readUnsignedShort();
128 if (withdrawnRoutesLength == 0 && totalPathAttrLength == 0) {
129 return builder.build();
131 if (totalPathAttrLength > 0) {
133 final Attributes attributes = this.reg.parseAttributes(buffer.readSlice(totalPathAttrLength), constraint);
134 builder.setAttributes(attributes);
135 } catch (final RuntimeException | BGPParsingException e) {
136 // Catch everything else and turn it into a BGPDocumentedException
137 throw new BGPDocumentedException("Could not parse BGP attributes.", BGPError.MALFORMED_ATTR_LIST, e);
140 final List<Ipv4Prefix> nlri = Ipv4Util.prefixListForBytes(ByteArray.readAllBytes(buffer));
141 if (!nlri.isEmpty()) {
142 // TODO handle NLRI with multiple paths - requires modified yang data model
143 builder.setNlri(new NlriBuilder().setNlri(nlri).build());
145 final Update msg = builder.build();
146 checkMandatoryAttributesPresence(msg);
147 LOG.debug("BGP Update message was parsed {}.", msg);
152 * Check for presence of well known mandatory path attributes
153 * ORIGIN, AS_PATH and NEXT_HOP in Update message
155 * @param message Update message
156 * @throws BGPDocumentedException
158 private static void checkMandatoryAttributesPresence(final Update message) throws BGPDocumentedException {
159 requireNonNull(message, "Update message cannot be null");
161 final Attributes attrs = message.getAttributes();
163 if (message.getNlri() != null) {
164 if (attrs == null || attrs.getCNextHop() == null) {
165 throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "NEXT_HOP",
166 BGPError.WELL_KNOWN_ATTR_MISSING,
167 new byte[] { NextHopAttributeParser.TYPE });
171 if (MessageUtil.isAnyNlriPresent(message)) {
172 if (attrs == null || attrs.getOrigin() == null) {
173 throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "ORIGIN",
174 BGPError.WELL_KNOWN_ATTR_MISSING,
175 new byte[] { OriginAttributeParser.TYPE });
178 if (attrs == null || attrs.getAsPath() == null) {
179 throw new BGPDocumentedException(BGPError.MANDATORY_ATTR_MISSING_MSG + "AS_PATH",
180 BGPError.WELL_KNOWN_ATTR_MISSING,
181 new byte[] { AsPathAttributeParser.TYPE });