| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hdfs.protocol.datatransfer; |
| |
| import java.io.DataInputStream; |
| import java.io.DataOutputStream; |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.PacketHeaderProto; |
| import org.apache.hadoop.hdfs.util.ByteBufferOutputStream; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.primitives.Shorts; |
| import com.google.common.primitives.Ints; |
| import com.google.protobuf.InvalidProtocolBufferException; |
| |
| /** |
| * Header data for each packet that goes through the read/write pipelines. |
| * Includes all of the information about the packet, excluding checksums and |
| * actual data. |
| * |
| * This data includes: |
| * - the offset in bytes into the HDFS block of the data in this packet |
| * - the sequence number of this packet in the pipeline |
| * - whether or not this is the last packet in the pipeline |
| * - the length of the data in this packet |
| * - whether or not this packet should be synced by the DNs. |
| * |
| * When serialized, this header is written out as a protocol buffer, preceded |
| * by a 4-byte integer representing the full packet length, and a 2-byte short |
| * representing the header length. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Evolving |
| public class PacketHeader { |
| private static final int MAX_PROTO_SIZE = PacketHeaderProto.newBuilder() |
| .setOffsetInBlock(0) |
| .setSeqno(0) |
| .setLastPacketInBlock(false) |
| .setDataLen(0) |
| .setSyncBlock(false) |
| .build().getSerializedSize(); |
| public static final int PKT_LENGTHS_LEN = |
| Ints.BYTES + Shorts.BYTES; |
| public static final int PKT_MAX_HEADER_LEN = |
| PKT_LENGTHS_LEN + MAX_PROTO_SIZE; |
| |
| private int packetLen; |
| private PacketHeaderProto proto; |
| |
| public PacketHeader() { |
| } |
| |
| public PacketHeader(int packetLen, long offsetInBlock, long seqno, |
| boolean lastPacketInBlock, int dataLen, boolean syncBlock) { |
| this.packetLen = packetLen; |
| Preconditions.checkArgument(packetLen >= Ints.BYTES, |
| "packet len %s should always be at least 4 bytes", |
| packetLen); |
| |
| PacketHeaderProto.Builder builder = PacketHeaderProto.newBuilder() |
| .setOffsetInBlock(offsetInBlock) |
| .setSeqno(seqno) |
| .setLastPacketInBlock(lastPacketInBlock) |
| .setDataLen(dataLen); |
| |
| if (syncBlock) { |
| // Only set syncBlock if it is specified. |
| // This is wire-incompatible with Hadoop 2.0.0-alpha due to HDFS-3721 |
| // because it changes the length of the packet header, and BlockReceiver |
| // in that version did not support variable-length headers. |
| builder.setSyncBlock(true); |
| } |
| |
| proto = builder.build(); |
| } |
| |
| public int getDataLen() { |
| return proto.getDataLen(); |
| } |
| |
| public boolean isLastPacketInBlock() { |
| return proto.getLastPacketInBlock(); |
| } |
| |
| public long getSeqno() { |
| return proto.getSeqno(); |
| } |
| |
| public long getOffsetInBlock() { |
| return proto.getOffsetInBlock(); |
| } |
| |
| public int getPacketLen() { |
| return packetLen; |
| } |
| |
| public boolean getSyncBlock() { |
| return proto.getSyncBlock(); |
| } |
| |
| @Override |
| public String toString() { |
| return "PacketHeader with packetLen=" + packetLen + |
| " header data: " + |
| proto.toString(); |
| } |
| |
| public void setFieldsFromData( |
| int packetLen, byte[] headerData) throws InvalidProtocolBufferException { |
| this.packetLen = packetLen; |
| proto = PacketHeaderProto.parseFrom(headerData); |
| } |
| |
| public void readFields(ByteBuffer buf) throws IOException { |
| packetLen = buf.getInt(); |
| short protoLen = buf.getShort(); |
| byte[] data = new byte[protoLen]; |
| buf.get(data); |
| proto = PacketHeaderProto.parseFrom(data); |
| } |
| |
| public void readFields(DataInputStream in) throws IOException { |
| this.packetLen = in.readInt(); |
| short protoLen = in.readShort(); |
| byte[] data = new byte[protoLen]; |
| in.readFully(data); |
| proto = PacketHeaderProto.parseFrom(data); |
| } |
| |
| /** |
| * @return the number of bytes necessary to write out this header, |
| * including the length-prefixing of the payload and header |
| */ |
| public int getSerializedSize() { |
| return PKT_LENGTHS_LEN + proto.getSerializedSize(); |
| } |
| |
| /** |
| * Write the header into the buffer. |
| * This requires that PKT_HEADER_LEN bytes are available. |
| */ |
| public void putInBuffer(final ByteBuffer buf) { |
| assert proto.getSerializedSize() <= MAX_PROTO_SIZE |
| : "Expected " + (MAX_PROTO_SIZE) + " got: " + proto.getSerializedSize(); |
| try { |
| buf.putInt(packetLen); |
| buf.putShort((short) proto.getSerializedSize()); |
| proto.writeTo(new ByteBufferOutputStream(buf)); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| public void write(DataOutputStream out) throws IOException { |
| assert proto.getSerializedSize() <= MAX_PROTO_SIZE |
| : "Expected " + (MAX_PROTO_SIZE) + " got: " + proto.getSerializedSize(); |
| out.writeInt(packetLen); |
| out.writeShort(proto.getSerializedSize()); |
| proto.writeTo(out); |
| } |
| |
| public byte[] getBytes() { |
| ByteBuffer buf = ByteBuffer.allocate(getSerializedSize()); |
| putInBuffer(buf); |
| return buf.array(); |
| } |
| |
| /** |
| * Perform a sanity check on the packet, returning true if it is sane. |
| * @param lastSeqNo the previous sequence number received - we expect the |
| * current sequence number to be larger by 1. |
| */ |
| public boolean sanityCheck(long lastSeqNo) { |
| // We should only have a non-positive data length for the last packet |
| if (proto.getDataLen() <= 0 && !proto.getLastPacketInBlock()) return false; |
| // The last packet should not contain data |
| if (proto.getLastPacketInBlock() && proto.getDataLen() != 0) return false; |
| // Seqnos should always increase by 1 with each packet received |
| return proto.getSeqno() == lastSeqNo + 1; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (!(o instanceof PacketHeader)) return false; |
| PacketHeader other = (PacketHeader)o; |
| return this.proto.equals(other.proto); |
| } |
| |
| @Override |
| public int hashCode() { |
| return (int)proto.getSeqno(); |
| } |
| } |