bgp/parser-impl/src/main/java/org/opendaylight/protocol/bgp/parser/impl/message/update/CommunitiesParser.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
   9 package org.opendaylight.protocol.bgp.parser.impl.message.update;
  10
  11 import java.util.Arrays;
  12
  13 import org.opendaylight.protocol.bgp.concepts.ASSpecificExtendedCommunity;
  14 import org.opendaylight.protocol.bgp.concepts.Community;
  15 import org.opendaylight.protocol.bgp.concepts.ExtendedCommunity;
  16 import org.opendaylight.protocol.bgp.concepts.Inet4SpecificExtendedCommunity;
  17 import org.opendaylight.protocol.bgp.concepts.OpaqueExtendedCommunity;
  18 import org.opendaylight.protocol.bgp.concepts.RouteOriginCommunity;
  19 import org.opendaylight.protocol.bgp.concepts.RouteTargetCommunity;
  20 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
  21 import org.opendaylight.protocol.bgp.parser.BGPError;
  22 import org.opendaylight.protocol.util.ByteArray;
  23 import org.opendaylight.protocol.concepts.ASNumber;
  24 import org.opendaylight.protocol.concepts.IPv4Address;
  25 import com.google.common.annotations.VisibleForTesting;
  26 import com.google.common.primitives.UnsignedBytes;
  27
  28 /**
  29  * Parser for Extended Communities Path Attribute.
  30  */
  31 public class CommunitiesParser {
  32
  33         public static final int EXTENDED_COMMUNITY_LENGTH = 8; // bytes
  34
  35         public static final int COMMUNITY_LENGTH = 4; // bytes
  36
  37         private static final int TYPE_LENGTH = 2; // bytes
  38
  39         private static final int AS_NUMBER_LENGTH = 2; // bytes
  40
  41         private static final int AS_LOCAL_ADMIN_LENGTH = 4; // bytes
  42
  43         private CommunitiesParser() {
  44
  45         }
  46
  47         /**
  48          * Parse known Community, if unknown, a new one will be created.
  49          *
  50          * @param bytes byte array to be parsed
  51          * @return new Community
  52          * @throws BGPDocumentedException
  53          */
  54         static Community parseCommunity(final byte[] bytes) throws BGPDocumentedException {
  55                 if (bytes.length != COMMUNITY_LENGTH)
  56                         throw new BGPDocumentedException("Community with wrong length: " + bytes.length, BGPError.OPT_ATTR_ERROR);
  57                 if (Arrays.equals(bytes, new byte[] { (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x01 })) {
  58                         return Community.NO_EXPORT;
  59                 } else if (Arrays.equals(bytes, new byte[] { (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x02 })) {
  60                         return Community.NO_ADVERTISE;
  61                 } else if (Arrays.equals(bytes, new byte[] { (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x03 })) {
  62                         return Community.NO_EXPORT_SUBCONFED;
  63                 }
  64                 return new Community(new ASNumber(ByteArray.bytesToLong(Arrays.copyOfRange(bytes, 0, AS_NUMBER_LENGTH))), ByteArray.bytesToInt(Arrays.copyOfRange(
  65                                 bytes, AS_NUMBER_LENGTH, AS_NUMBER_LENGTH + AS_NUMBER_LENGTH)));
  66         }
  67
  68         /**
  69          * Parse Extended Community according to their type.
  70          *
  71          * @param bytes byte array to be parsed
  72          * @return new Specific Extended Community
  73          * @throws BGPDocumentedException if the type is not recognized
  74          */
  75         @VisibleForTesting
  76         public static ExtendedCommunity parseExtendedCommunity(final byte[] bytes) throws BGPDocumentedException {
  77                 // final int type = ByteArray.bytesToInt(ByteArray.subByte(bytes, 0, TYPE_LENGTH));
  78                 final int type = UnsignedBytes.toInt(bytes[0]);
  79                 final int subType = UnsignedBytes.toInt(bytes[1]);
  80                 final byte[] value = ByteArray.subByte(bytes, TYPE_LENGTH, bytes.length - TYPE_LENGTH);
  81                 switch (type) {
  82                 case 0:
  83                         if (subType == 2) {
  84                                 return new RouteTargetCommunity(new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0, AS_NUMBER_LENGTH))), ByteArray.subByte(
  85                                                 value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
  86                         } else if (subType == 3) {
  87                                 return new RouteOriginCommunity(new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0, AS_NUMBER_LENGTH))), ByteArray.subByte(
  88                                                 value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
  89                         } else
  90                                 return new ASSpecificExtendedCommunity(false, subType, new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0,
  91                                                 AS_NUMBER_LENGTH))), ByteArray.subByte(value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
  92                 case 40: // 01000000
  93                         return new ASSpecificExtendedCommunity(true, subType, new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0,
  94                                         AS_NUMBER_LENGTH))), ByteArray.subByte(value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
  95                 case 2:
  96                         if (subType == 2) {
  97                                 return new RouteTargetCommunity(new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0, AS_NUMBER_LENGTH))), ByteArray.subByte(
  98                                                 value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
  99                         } else if (subType == 3) {
 100                                 return new RouteOriginCommunity(new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0, AS_NUMBER_LENGTH))), ByteArray.subByte(
 101                                                 value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
 102                         } else
 103                                 throw new BGPDocumentedException("Could not parse Extended Community subtype: " + subType, BGPError.OPT_ATTR_ERROR);
 104                 case 1:
 105                         if (subType == 2) {
 106                                 return new RouteTargetCommunity(new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0, AS_NUMBER_LENGTH))), ByteArray.subByte(
 107                                                 value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
 108                         } else if (subType == 3) {
 109                                 return new RouteOriginCommunity(new ASNumber(ByteArray.bytesToInt(ByteArray.subByte(value, 0, AS_NUMBER_LENGTH))), ByteArray.subByte(
 110                                                 value, AS_NUMBER_LENGTH, AS_LOCAL_ADMIN_LENGTH));
 111                         } else
 112                                 return new Inet4SpecificExtendedCommunity(false, subType, new IPv4Address(ByteArray.subByte(value, 0, 4)), ByteArray.subByte(
 113                                                 value, 4, 2));
 114                 case 41: // 01000001
 115                         return new Inet4SpecificExtendedCommunity(true, subType, new IPv4Address(ByteArray.subByte(value, 0, 4)), ByteArray.subByte(
 116                                         value, 4, 2));
 117                 case 3:
 118                         return new OpaqueExtendedCommunity(false, subType, value);
 119                 case 43: // 01000011
 120                         return new OpaqueExtendedCommunity(true, subType, value);
 121                 default:
 122                         throw new BGPDocumentedException("Could not parse Extended Community type: " + type, BGPError.OPT_ATTR_ERROR);
 123                 }
 124         }
 125 }