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The Netty project is an effort to provide an asynchronous event-driven
network application framework and tools for rapid development of
maintainable high performance and high scalability protocol servers and
clients. In other words, Netty is a NIO client server framework which
enables quick and easy development of network applications such as protocol
servers and clients. It greatly simplifies and streamlines network
programming such as TCP and UDP socket server.
/*
* Copyright 2014 The Netty Project
*
* The Netty Project 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.jboss.netty.handler.codec.spdy;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import static org.jboss.netty.handler.codec.spdy.SpdyCodecUtil.*;
public class SpdyHeaderBlockRawDecoder extends SpdyHeaderBlockDecoder {
private static final int LENGTH_FIELD_SIZE = 4;
private final int maxHeaderSize;
private State state;
private ChannelBuffer cumulation;
private int headerSize;
private int numHeaders;
private int length;
private String name;
private enum State {
READ_NUM_HEADERS,
READ_NAME_LENGTH,
READ_NAME,
SKIP_NAME,
READ_VALUE_LENGTH,
READ_VALUE,
SKIP_VALUE,
END_HEADER_BLOCK,
ERROR
}
public SpdyHeaderBlockRawDecoder(SpdyVersion spdyVersion, int maxHeaderSize) {
if (spdyVersion == null) {
throw new NullPointerException("spdyVersion");
}
this.maxHeaderSize = maxHeaderSize;
this.state = State.READ_NUM_HEADERS;
}
private int readLengthField(ChannelBuffer buffer) {
int length = getSignedInt(buffer, buffer.readerIndex());
buffer.skipBytes(LENGTH_FIELD_SIZE);
return length;
}
@Override
void decode(ChannelBuffer headerBlock, SpdyHeadersFrame frame) throws Exception {
if (headerBlock == null) {
throw new NullPointerException("headerBlock");
}
if (frame == null) {
throw new NullPointerException("frame");
}
if (cumulation == null) {
decodeHeaderBlock(headerBlock, frame);
if (headerBlock.readable()) {
cumulation = ChannelBuffers.dynamicBuffer(headerBlock.readableBytes());
cumulation.writeBytes(headerBlock);
}
} else {
cumulation.writeBytes(headerBlock);
decodeHeaderBlock(cumulation, frame);
if (cumulation.readable()) {
cumulation.discardReadBytes();
} else {
cumulation = null;
}
}
}
protected void decodeHeaderBlock(ChannelBuffer headerBlock, SpdyHeadersFrame frame) throws Exception {
int skipLength;
while (headerBlock.readable()) {
switch(state) {
case READ_NUM_HEADERS:
if (headerBlock.readableBytes() < LENGTH_FIELD_SIZE) {
return;
}
numHeaders = readLengthField(headerBlock);
if (numHeaders < 0) {
state = State.ERROR;
frame.setInvalid();
} else if (numHeaders == 0) {
state = State.END_HEADER_BLOCK;
} else {
state = State.READ_NAME_LENGTH;
}
break;
case READ_NAME_LENGTH:
if (headerBlock.readableBytes() < LENGTH_FIELD_SIZE) {
return;
}
length = readLengthField(headerBlock);
// Recipients of a zero-length name must issue a stream error
if (length <= 0) {
state = State.ERROR;
frame.setInvalid();
} else if (length > maxHeaderSize || headerSize > maxHeaderSize - length) {
headerSize = maxHeaderSize + 1;
state = State.SKIP_NAME;
frame.setTruncated();
} else {
headerSize += length;
state = State.READ_NAME;
}
break;
case READ_NAME:
if (headerBlock.readableBytes() < length) {
return;
}
byte[] nameBytes = new byte[length];
headerBlock.readBytes(nameBytes);
name = new String(nameBytes, "UTF-8");
// Check for identically named headers
if (frame.headers().contains(name)) {
state = State.ERROR;
frame.setInvalid();
} else {
state = State.READ_VALUE_LENGTH;
}
break;
case SKIP_NAME:
skipLength = Math.min(headerBlock.readableBytes(), length);
headerBlock.skipBytes(skipLength);
length -= skipLength;
if (length == 0) {
state = State.READ_VALUE_LENGTH;
}
break;
case READ_VALUE_LENGTH:
if (headerBlock.readableBytes() < LENGTH_FIELD_SIZE) {
return;
}
length = readLengthField(headerBlock);
// Recipients of illegal value fields must issue a stream error
if (length < 0) {
state = State.ERROR;
frame.setInvalid();
} else if (length == 0) {
if (!frame.isTruncated()) {
// SPDY/3 allows zero-length (empty) header values
frame.headers().add(name, "");
}
name = null;
if (--numHeaders == 0) {
state = State.END_HEADER_BLOCK;
} else {
state = State.READ_NAME_LENGTH;
}
} else if (length > maxHeaderSize || headerSize > maxHeaderSize - length) {
headerSize = maxHeaderSize + 1;
name = null;
state = State.SKIP_VALUE;
frame.setTruncated();
} else {
headerSize += length;
state = State.READ_VALUE;
}
break;
case READ_VALUE:
if (headerBlock.readableBytes() < length) {
return;
}
byte[] valueBytes = new byte[length];
headerBlock.readBytes(valueBytes);
// Add Name/Value pair to headers
int index = 0;
int offset = 0;
// Value must not start with a NULL character
if (valueBytes[0] == (byte) 0) {
state = State.ERROR;
frame.setInvalid();
break;
}
while (index < length) {
while (index < valueBytes.length && valueBytes[index] != (byte) 0) {
index ++;
}
if (index < valueBytes.length) {
// Received NULL character
if (index + 1 == valueBytes.length || valueBytes[index + 1] == (byte) 0) {
// Value field ended with a NULL character or
// received multiple, in-sequence NULL characters.
// Recipients of illegal value fields must issue a stream error
state = State.ERROR;
frame.setInvalid();
break;
}
}
String value = new String(valueBytes, offset, index - offset, "UTF-8");
try {
frame.headers().add(name, value);
} catch (IllegalArgumentException e) {
// Name contains NULL or non-ascii characters
state = State.ERROR;
frame.setInvalid();
break;
}
index ++;
offset = index;
}
name = null;
// If we broke out of the add header loop, break here
if (state == State.ERROR) {
break;
}
if (--numHeaders == 0) {
state = State.END_HEADER_BLOCK;
} else {
state = State.READ_NAME_LENGTH;
}
break;
case SKIP_VALUE:
skipLength = Math.min(headerBlock.readableBytes(), length);
headerBlock.skipBytes(skipLength);
length -= skipLength;
if (length == 0) {
if (--numHeaders == 0) {
state = State.END_HEADER_BLOCK;
} else {
state = State.READ_NAME_LENGTH;
}
}
break;
case END_HEADER_BLOCK:
state = State.ERROR;
frame.setInvalid();
break;
case ERROR:
headerBlock.skipBytes(headerBlock.readableBytes());
return;
default:
throw new Error("Shouldn't reach here.");
}
}
}
@Override
void endHeaderBlock(SpdyHeadersFrame frame) throws Exception {
if (state != State.END_HEADER_BLOCK) {
frame.setInvalid();
}
cumulation = null;
// Initialize header block decoding fields
headerSize = 0;
name = null;
state = State.READ_NUM_HEADERS;
}
@Override
void end() {
cumulation = null;
}
}