packethandler/implementation/src/main/java/org/opendaylight/l2switch/packethandler/decoders/EthernetDecoder.java

   1 package org.opendaylight.l2switch.packethandler.decoders;
   2
   3 import org.opendaylight.controller.sal.packet.BitBufferHelper;
   4 import org.opendaylight.controller.sal.packet.BufferException;
   5 import org.opendaylight.controller.sal.utils.HexEncode;
   6 import org.opendaylight.controller.sal.utils.NetUtils;
   7 import org.opendaylight.l2switch.packethandler.decoders.PacketDecoder;
   8 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.yang.types.rev100924.MacAddress;
   9 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.basepacket.rev140528.Packet;
  10 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.basepacket.rev140528.PacketType;
  11 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.basepacket.rev140528.packet.PacketPayloadTypeBuilder;
  12 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.basepacket.rev140528.packet.RawPacket;
  13 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.basepacket.rev140528.packet.RawPacketBuilder;
  14 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.ethernet.rev140528.EthernetPacketBuilder;
  15 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.ethernet.rev140528.EthernetPacketGrp;
  16 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.ethernet.rev140528.EthernetPacketReceivedBuilder;
  17 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.ethernet.rev140528.Header8021qType;
  18 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.ethernet.rev140528.KnownEtherType;
  19 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.ethernet.rev140528.ethernet.packet.grp.Header8021q;
  20 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.ethernet.rev140528.ethernet.packet.grp.Header8021qBuilder;
  21 import org.opendaylight.yangtools.yang.binding.Notification;
  22 import org.slf4j.Logger;
  23 import org.slf4j.LoggerFactory;
  24
  25 import java.util.ArrayList;
  26 import java.util.Arrays;
  27
  28 /**
  29  * Ethernet Packet Decoder
  30  */
  31 public class EthernetDecoder implements PacketDecoder {
  32   private static final Logger _logger = LoggerFactory.getLogger(EthernetDecoder.class);
  33   public static final Integer LENGTH_MAX = 1500;
  34   public static final Integer ETHERTYPE_MIN = 1536;
  35   public static final Integer ETHERTYPE_8021Q = 0x8100;
  36   public static final Integer ETHERTYPE_QINQ = 0x9100;
  37
  38   /**
  39    * Decode a RawPacket into an EthernetPacket
  40    *
  41    * @param packet -- data from wire to deserialize
  42    * @return
  43    * @throws BufferException
  44    */
  45   @Override
  46   public Packet decode(Packet packet) {
  47     RawPacket rawPacket = packet.getRawPacket();
  48     EthernetPacketBuilder builder = new EthernetPacketBuilder();
  49     byte[] data = rawPacket.getPayload();
  50
  51     try {
  52       // Save original rawPacket
  53       builder.setRawPacket(new RawPacketBuilder().setIngress(rawPacket.getIngress()).setPayload(data).build());
  54
  55       // Deserialize the destination & source fields
  56       builder.setDestinationMac(new MacAddress(HexEncode.bytesToHexStringFormat(BitBufferHelper.getBits(data, 0, 48))));
  57       builder.setSourceMac(new MacAddress(HexEncode.bytesToHexStringFormat(BitBufferHelper.getBits(data, 48, 48))));
  58
  59       // Deserialize the optional field 802.1Q headers
  60       Integer nextField = BitBufferHelper.getInt(BitBufferHelper.getBits(data, 96, 16));
  61       int extraHeaderBits = 0;
  62       ArrayList<Header8021q> headerList = new ArrayList<Header8021q>();
  63       while(nextField.equals(ETHERTYPE_8021Q) || nextField.equals(ETHERTYPE_QINQ)) {
  64         Header8021qBuilder hBuilder = new Header8021qBuilder();
  65         hBuilder.setType(Header8021qType.forValue(nextField));
  66
  67         // Read 2 more bytes for priority (3bits), drop eligible (1bit), vlan-id (12bits)
  68         byte[] vlanBytes = BitBufferHelper.getBits(data, 112 + extraHeaderBits, 16);
  69
  70         // Remove the sign & right-shift to get the priority code
  71         hBuilder.setPriorityCode((short) ((vlanBytes[0] & 0xff) >> 5));
  72
  73         // Remove the sign & remove priority code bits & right-shift to get drop-eligible bit
  74         hBuilder.setDropEligible(1 == (((vlanBytes[0] & 0xff) & 0x10) >> 4));
  75
  76         // Remove priority code & drop-eligible bits, to get the VLAN-id
  77         vlanBytes[0] = (byte) (vlanBytes[0] & 0x0F);
  78         hBuilder.setVlan(BitBufferHelper.getInt(vlanBytes));
  79
  80         // Add 802.1Q header to the growing collection
  81         headerList.add(hBuilder.build());
  82
  83         // Reset value of "nextField" to correspond to following 2 bytes for next 802.1Q header or EtherType/Length
  84         nextField = BitBufferHelper.getInt(BitBufferHelper.getBits(data, 128 + extraHeaderBits, 16));
  85
  86         // 802.1Q header means payload starts at a later position
  87         extraHeaderBits += 32;
  88       }
  89       // Set 802.1Q headers
  90       if(!headerList.isEmpty()) {
  91         builder.setHeader8021q(headerList);
  92       }
  93
  94       // Deserialize the EtherType or Length field
  95       if(nextField >= ETHERTYPE_MIN) {
  96         builder.setEthertype(KnownEtherType.forValue(nextField));
  97       } else if(nextField <= LENGTH_MAX) {
  98         builder.setEthernetLength(nextField);
  99       } else {
 100         _logger.debug("Undefined header, value is not valid EtherType or length.  Value is " + nextField);
 101       }
 102
 103       // Deserialize the payload now
 104       int payloadStart = 96 + 16 + extraHeaderBits;
 105       int payloadSize = data.length * NetUtils.NumBitsInAByte - payloadStart;
 106       int start = payloadStart / NetUtils.NumBitsInAByte;
 107       int stop = start + payloadSize / NetUtils.NumBitsInAByte;
 108       builder.setEthernetPayload(Arrays.copyOfRange(data, start, stop));
 109
 110       if(null != builder.getEthertype()) {
 111         builder.setPacketPayloadType(new PacketPayloadTypeBuilder()
 112             .setPacketType(PacketType.Ethernet)
 113             .setPayloadType(builder.getEthertype().getIntValue())
 114             .build());
 115       }
 116
 117     } catch(BufferException be) {
 118       _logger.info("Exception during decoding raw packet to ethernet.");
 119     }
 120
 121     return builder.build();
 122
 123     //ToDo:  Possibly log these values
 124       /*if (_logger.isTraceEnabled()) {
 125         _logger.trace("{}: {}: {} (offset {} bitsize {})",
 126           new Object[] { this.getClass().getSimpleName(), hdrField,
 127             HexEncode.bytesToHexString(hdrFieldBytes),
 128             startOffset, numBits });
 129       }*/
 130   }
 131
 132   @Override
 133   public Notification buildPacketNotification(Packet decodedPacket) {
 134     if(!(decodedPacket instanceof EthernetPacketGrp)) return null;
 135
 136     EthernetPacketReceivedBuilder ethernetPacketReceivedBuilder = new EthernetPacketReceivedBuilder((EthernetPacketGrp) decodedPacket);
 137     return ethernetPacketReceivedBuilder.build();
 138   }
 139 }