bgp/parser-impl/src/main/java/org/opendaylight/protocol/bgp/parser/impl/message/update/AsPathAttributeParser.java

   1 package org.opendaylight.protocol.bgp.parser.impl.message.update;
   2
   3 import java.util.List;
   4
   5 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
   6 import org.opendaylight.protocol.bgp.parser.BGPError;
   7 import org.opendaylight.protocol.bgp.parser.BGPParsingException;
   8 import org.opendaylight.protocol.bgp.parser.impl.message.update.AsPathSegmentParser.SegmentType;
   9 import org.opendaylight.protocol.bgp.parser.spi.AttributeParser;
  10 import org.opendaylight.protocol.util.ByteArray;
  11 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.AsNumber;
  12 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130918.path.attributes.AsPath;
  13 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130918.path.attributes.AsPathBuilder;
  14 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130918.path.attributes.as.path.Segments;
  15 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130918.path.attributes.as.path.SegmentsBuilder;
  16 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130918.update.PathAttributesBuilder;
  17 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.as.path.segment.c.segment.CAListBuilder;
  18 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.as.path.segment.c.segment.CASetBuilder;
  19 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.as.path.segment.c.segment.c.a.list.AsSequence;
  20
  21 import com.google.common.collect.Lists;
  22 import com.google.common.primitives.UnsignedBytes;
  23
  24 final class AsPathAttributeParser implements AttributeParser {
  25         static final int TYPE = 2;
  26
  27         /**
  28          * Parses AS_PATH from bytes.
  29          *
  30          * @param bytes byte array to be parsed
  31          * @return new ASPath object
  32          * @throws BGPDocumentedException if there is no AS_SEQUENCE present (mandatory)
  33          * @throws BGPParsingException
  34          */
  35         private static AsPath parseAsPath(final byte[] bytes) throws BGPDocumentedException, BGPParsingException {
  36                 int byteOffset = 0;
  37                 final List<Segments> ases = Lists.newArrayList();
  38                 boolean isSequence = false;
  39                 while (byteOffset < bytes.length) {
  40                         final int type = UnsignedBytes.toInt(bytes[byteOffset]);
  41                         final SegmentType segmentType = AsPathSegmentParser.parseType(type);
  42                         if (segmentType == null) {
  43                                 throw new BGPParsingException("AS Path segment type unknown : " + type);
  44                         }
  45                         byteOffset += AsPathSegmentParser.TYPE_LENGTH;
  46
  47                         final int count = UnsignedBytes.toInt(bytes[byteOffset]);
  48                         byteOffset += AsPathSegmentParser.LENGTH_SIZE;
  49
  50                         if (segmentType == SegmentType.AS_SEQUENCE) {
  51                                 final List<AsSequence> numbers = AsPathSegmentParser.parseAsSequence(count,
  52                                                 ByteArray.subByte(bytes, byteOffset, count * AsPathSegmentParser.AS_NUMBER_LENGTH));
  53                                 ases.add(new SegmentsBuilder().setCSegment(new CAListBuilder().setAsSequence(numbers).build()).build());
  54                                 isSequence = true;
  55                         } else {
  56                                 final List<AsNumber> list = AsPathSegmentParser.parseAsSet(count,
  57                                                 ByteArray.subByte(bytes, byteOffset, count * AsPathSegmentParser.AS_NUMBER_LENGTH));
  58                                 ases.add(new SegmentsBuilder().setCSegment(new CASetBuilder().setAsSet(list).build()).build());
  59
  60                         }
  61                         byteOffset += count * AsPathSegmentParser.AS_NUMBER_LENGTH;
  62                 }
  63
  64                 if (!isSequence && bytes.length != 0) {
  65                         throw new BGPDocumentedException("AS_SEQUENCE must be present in AS_PATH attribute.", BGPError.AS_PATH_MALFORMED);
  66                 }
  67                 return new AsPathBuilder().setSegments(ases).build();
  68         }
  69
  70         @Override
  71         public void parseAttribute(final byte[] bytes, final PathAttributesBuilder builder)     throws BGPDocumentedException, BGPParsingException {
  72                 builder.setAsPath(parseAsPath(bytes));
  73         }
  74 }