/*
* 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.cassandra.transport;
import java.io.IOException;
import java.util.EnumSet;
import java.util.List;
import io.netty.buffer.ByteBuf;
import io.netty.channel.*;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.MessageToMessageDecoder;
import io.netty.handler.codec.MessageToMessageEncoder;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.exceptions.InvalidRequestException;
import org.apache.cassandra.transport.messages.ErrorMessage;
public class Frame
{
public final Header header;
public final ByteBuf body;
/**
* An on-wire frame consists of a header and a body.
*
* The header is defined the following way in native protocol version 3 and later:
*
* 0 8 16 24 32 40
* +---------+---------+---------+---------+---------+
* | version | flags | stream | opcode |
* +---------+---------+---------+---------+---------+
* | length |
* +---------+---------+---------+---------+
*
*
* In versions 1 and 2 the header has a smaller (1 byte) stream id, and is thus defined the following way:
*
* 0 8 16 24 32
* +---------+---------+---------+---------+
* | version | flags | stream | opcode |
* +---------+---------+---------+---------+
* | length |
* +---------+---------+---------+---------+
*/
private Frame(Header header, ByteBuf body)
{
this.header = header;
this.body = body;
}
public void retain()
{
body.retain();
}
public boolean release()
{
return body.release();
}
public static Frame create(Message.Type type, int streamId, int version, EnumSet<Header.Flag> flags, ByteBuf body)
{
Header header = new Header(version, flags, streamId, type);
return new Frame(header, body);
}
public static class Header
{
// 8 bytes in protocol versions 1 and 2, 8 bytes in protocol version 3 and later
public static final int MODERN_LENGTH = 9;
public static final int LEGACY_LENGTH = 8;
public static final int BODY_LENGTH_SIZE = 4;
public final int version;
public final EnumSet<Flag> flags;
public final int streamId;
public final Message.Type type;
private Header(int version, int flags, int streamId, Message.Type type)
{
this(version, Flag.deserialize(flags), streamId, type);
}
private Header(int version, EnumSet<Flag> flags, int streamId, Message.Type type)
{
this.version = version;
this.flags = flags;
this.streamId = streamId;
this.type = type;
}
public static enum Flag
{
// The order of that enum matters!!
COMPRESSED,
TRACING;
private static final Flag[] ALL_VALUES = values();
public static EnumSet<Flag> deserialize(int flags)
{
EnumSet<Flag> set = EnumSet.noneOf(Flag.class);
for (int n = 0; n < ALL_VALUES.length; n++)
{
if ((flags & (1 << n)) != 0)
set.add(ALL_VALUES[n]);
}
return set;
}
public static int serialize(EnumSet<Flag> flags)
{
int i = 0;
for (Flag flag : flags)
i |= 1 << flag.ordinal();
return i;
}
}
}
public Frame with(ByteBuf newBody)
{
return new Frame(header, newBody);
}
public static class Decoder extends ByteToMessageDecoder
{
private static final int MAX_FRAME_LENGTH = DatabaseDescriptor.getNativeTransportMaxFrameSize();
private boolean discardingTooLongFrame;
private long tooLongFrameLength;
private long bytesToDiscard;
private int tooLongStreamId;
private final Connection.Factory factory;
public Decoder(Connection.Factory factory)
{
this.factory = factory;
}
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf buffer, List<Object> results)
throws Exception
{
if (discardingTooLongFrame)
{
bytesToDiscard = discard(buffer, bytesToDiscard);
// If we have discarded everything, throw the exception
if (bytesToDiscard <= 0)
fail();
return;
}
// Wait until we have read at least the short header
if (buffer.readableBytes() < Header.LEGACY_LENGTH)
return;
int idx = buffer.readerIndex();
int firstByte = buffer.getByte(idx++);
Message.Direction direction = Message.Direction.extractFromVersion(firstByte);
int version = firstByte & 0x7F;
if (version > Server.CURRENT_VERSION)
throw new ProtocolException("Invalid or unsupported protocol version: " + version);
// Wait until we have the complete V3+ header
if (version >= Server.VERSION_3 && buffer.readableBytes() < Header.MODERN_LENGTH)
return;
int flags = buffer.getByte(idx++);
int streamId, headerLength;
if (version >= Server.VERSION_3)
{
streamId = buffer.getShort(idx);
idx += 2;
headerLength = Header.MODERN_LENGTH;
}
else
{
streamId = buffer.getByte(idx);
idx++;
headerLength = Header.LEGACY_LENGTH;
}
// This throws a protocol exceptions if the opcode is unknown
Message.Type type = Message.Type.fromOpcode(buffer.getByte(idx++), direction);
long bodyLength = buffer.getUnsignedInt(idx);
idx += Header.BODY_LENGTH_SIZE;
if (bodyLength < 0)
{
buffer.skipBytes(headerLength);
throw new ProtocolException("Invalid frame body length: " + bodyLength);
}
long frameLength = bodyLength + headerLength;
if (frameLength > MAX_FRAME_LENGTH)
{
// Enter the discard mode and discard everything received so far.
discardingTooLongFrame = true;
tooLongStreamId = streamId;
tooLongFrameLength = frameLength;
bytesToDiscard = discard(buffer, frameLength);
if (bytesToDiscard <= 0)
fail();
return;
}
if (buffer.readableBytes() < frameLength)
return;
// extract body
ByteBuf body = buffer.slice(idx, (int) bodyLength);
body.retain();
idx += bodyLength;
buffer.readerIndex(idx);
Connection connection = ctx.channel().attr(Connection.attributeKey).get();
if (connection == null)
{
// First message seen on this channel, attach the connection object
connection = factory.newConnection(ctx.channel(), version);
ctx.channel().attr(Connection.attributeKey).set(connection);
}
else if (connection.getVersion() != version)
{
throw new ProtocolException(String.format("Invalid message version. Got %d but previous messages on this connection had version %d", version, connection.getVersion()));
}
results.add(new Frame(new Header(version, flags, streamId, type), body));
}
private void fail()
{
// Reset to the initial state and throw the exception
long tooLongFrameLength = this.tooLongFrameLength;
this.tooLongFrameLength = 0;
discardingTooLongFrame = false;
String msg = String.format("Request is too big: length %d exceeds maximum allowed length %d.", tooLongFrameLength, MAX_FRAME_LENGTH);
throw ErrorMessage.wrap(new InvalidRequestException(msg), tooLongStreamId);
}
}
// How much remains to be discarded
private static long discard(ByteBuf buffer, long remainingToDiscard)
{
int availableToDiscard = (int) Math.min(remainingToDiscard, buffer.readableBytes());
buffer.skipBytes(availableToDiscard);
return remainingToDiscard - availableToDiscard;
}
@ChannelHandler.Sharable
public static class Encoder extends MessageToMessageEncoder<Frame>
{
public void encode(ChannelHandlerContext ctx, Frame frame, List<Object> results)
throws IOException
{
int headerLength = frame.header.version >= Server.VERSION_3
? Header.MODERN_LENGTH
: Header.LEGACY_LENGTH;
ByteBuf header = CBUtil.allocator.buffer(headerLength);
Message.Type type = frame.header.type;
header.writeByte(type.direction.addToVersion(frame.header.version));
header.writeByte(Header.Flag.serialize(frame.header.flags));
if (frame.header.version >= Server.VERSION_3)
header.writeShort(frame.header.streamId);
else
header.writeByte(frame.header.streamId);
header.writeByte(type.opcode);
header.writeInt(frame.body.readableBytes());
results.add(header);
results.add(frame.body);
}
}
@ChannelHandler.Sharable
public static class Decompressor extends MessageToMessageDecoder<Frame>
{
public void decode(ChannelHandlerContext ctx, Frame frame, List<Object> results)
throws IOException
{
Connection connection = ctx.channel().attr(Connection.attributeKey).get();
if (!frame.header.flags.contains(Header.Flag.COMPRESSED) || connection == null)
{
results.add(frame);
return;
}
FrameCompressor compressor = connection.getCompressor();
if (compressor == null)
{
results.add(frame);
return;
}
results.add(compressor.decompress(frame));
}
}
@ChannelHandler.Sharable
public static class Compressor extends MessageToMessageEncoder<Frame>
{
public void encode(ChannelHandlerContext ctx, Frame frame, List<Object> results)
throws IOException
{
Connection connection = ctx.channel().attr(Connection.attributeKey).get();
// Never compress STARTUP messages
if (frame.header.type == Message.Type.STARTUP || connection == null)
{
results.add(frame);
return;
}
FrameCompressor compressor = connection.getCompressor();
if (compressor == null)
{
results.add(frame);
return;
}
frame.header.flags.add(Header.Flag.COMPRESSED);
results.add(compressor.compress(frame));
}
}
}