1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.handler.codec.marshalling;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.channel.Channel;
20 import io.netty.channel.ChannelHandlerContext;
21 import io.netty.handler.codec.ReplayingDecoder;
22 import io.netty.handler.codec.TooLongFrameException;
23 import org.jboss.marshalling.ByteInput;
24 import org.jboss.marshalling.Unmarshaller;
25
26 import java.io.ObjectStreamConstants;
27 import java.util.List;
28
29 /**
30 * {@link ReplayingDecoder} which use an {@link Unmarshaller} to read the Object out of the {@link ByteBuf}.
31 *
32 * If you can you should use {@link MarshallingDecoder}.
33 */
34 public class CompatibleMarshallingDecoder extends ReplayingDecoder<Void> {
35 protected final UnmarshallerProvider provider;
36 protected final int maxObjectSize;
37 private boolean discardingTooLongFrame;
38
39 /**
40 * Create a new instance of {@link CompatibleMarshallingDecoder}.
41 *
42 * @param provider
43 * the {@link UnmarshallerProvider} which is used to obtain the {@link Unmarshaller}
44 * for the {@link Channel}
45 * @param maxObjectSize
46 * the maximal size (in bytes) of the {@link Object} to unmarshal. Once the size is
47 * exceeded the {@link Channel} will get closed. Use a a maxObjectSize of
48 * {@link Integer#MAX_VALUE} to disable this. You should only do this if you are sure
49 * that the received Objects will never be big and the sending side are trusted, as this
50 * opens the possibility for a DOS-Attack due an {@link OutOfMemoryError}.
51 */
52 public CompatibleMarshallingDecoder(UnmarshallerProvider provider, int maxObjectSize) {
53 this.provider = provider;
54 this.maxObjectSize = maxObjectSize;
55 }
56
57 @Override
58 protected void decode(ChannelHandlerContext ctx, ByteBuf buffer, List<Object> out) throws Exception {
59 if (discardingTooLongFrame) {
60 buffer.skipBytes(actualReadableBytes());
61 checkpoint();
62 return;
63 }
64
65 Unmarshaller unmarshaller = provider.getUnmarshaller(ctx);
66 ByteInput input = new ChannelBufferByteInput(buffer);
67 if (maxObjectSize != Integer.MAX_VALUE) {
68 input = new LimitingByteInput(input, maxObjectSize);
69 }
70 try {
71 unmarshaller.start(input);
72 Object obj = unmarshaller.readObject();
73 unmarshaller.finish();
74 out.add(obj);
75 } catch (LimitingByteInput.TooBigObjectException ignored) {
76 discardingTooLongFrame = true;
77 throw new TooLongFrameException();
78 } finally {
79 // Call close in a finally block as the ReplayingDecoder will throw an Error if not enough bytes are
80 // readable. This helps to be sure that we do not leak resource
81 unmarshaller.close();
82 }
83 }
84
85 @Override
86 protected void decodeLast(ChannelHandlerContext ctx, ByteBuf buffer, List<Object> out) throws Exception {
87 switch (buffer.readableBytes()) {
88 case 0:
89 return;
90 case 1:
91 // Ignore the last TC_RESET
92 if (buffer.getByte(buffer.readerIndex()) == ObjectStreamConstants.TC_RESET) {
93 buffer.skipBytes(1);
94 return;
95 }
96 }
97
98 decode(ctx, buffer, out);
99 }
100
101 @Override
102 public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
103 if (cause instanceof TooLongFrameException) {
104 ctx.close();
105 } else {
106 super.exceptionCaught(ctx, cause);
107 }
108 }
109 }