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//
// ========================================================================
// Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.websocket.common;
import java.nio.ByteBuffer;
import java.util.List;
import org.eclipse.jetty.io.ByteBufferPool;
import org.eclipse.jetty.util.BufferUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
import org.eclipse.jetty.websocket.api.ProtocolException;
import org.eclipse.jetty.websocket.api.WebSocketBehavior;
import org.eclipse.jetty.websocket.api.WebSocketPolicy;
import org.eclipse.jetty.websocket.api.extensions.Extension;
import org.eclipse.jetty.websocket.api.extensions.Frame;
/**
* Generating a frame in WebSocket land.
*
*
*/
public class Generator
{
private static final Logger LOG = Log.getLogger(Generator.class);
/**
* The overhead (maximum) for a framing header. Assuming a maximum sized payload with masking key.
*/
public static final int OVERHEAD = 28;
private final WebSocketBehavior behavior;
private final ByteBufferPool bufferPool;
private boolean validating;
/** Is there an extension using RSV1 */
private boolean rsv1InUse = false;
/** Is there an extension using RSV2 */
private boolean rsv2InUse = false;
/** Is there an extension using RSV3 */
private boolean rsv3InUse = false;
/**
* Construct Generator with provided policy and bufferPool
*
* @param policy
* the policy to use
* @param bufferPool
* the buffer pool to use
*/
public Generator(WebSocketPolicy policy, ByteBufferPool bufferPool)
{
this(policy,bufferPool,true);
}
/**
* Construct Generator with provided policy and bufferPool
*
* @param policy
* the policy to use
* @param bufferPool
* the buffer pool to use
* @param validating
* true to enable RFC frame validation
*/
public Generator(WebSocketPolicy policy, ByteBufferPool bufferPool, boolean validating)
{
this.behavior = policy.getBehavior();
this.bufferPool = bufferPool;
this.validating = validating;
}
public void assertFrameValid(Frame frame)
{
if (!validating)
{
return;
}
/*
* RFC 6455 Section 5.2
*
* MUST be 0 unless an extension is negotiated that defines meanings for non-zero values. If a nonzero value is received and none of the negotiated
* extensions defines the meaning of such a nonzero value, the receiving endpoint MUST _Fail the WebSocket Connection_.
*/
if (!rsv1InUse && frame.isRsv1())
{
throw new ProtocolException("RSV1 not allowed to be set");
}
if (!rsv2InUse && frame.isRsv2())
{
throw new ProtocolException("RSV2 not allowed to be set");
}
if (!rsv3InUse && frame.isRsv3())
{
throw new ProtocolException("RSV3 not allowed to be set");
}
if (frame.getType().isControl())
{
/*
* RFC 6455 Section 5.5
*
* All control frames MUST have a payload length of 125 bytes or less and MUST NOT be fragmented.
*/
if (frame.getPayloadLength() > 125)
{
throw new ProtocolException("Invalid control frame payload length");
}
if (!frame.isFin())
{
throw new ProtocolException("Control Frames must be FIN=true");
}
/*
* RFC 6455 Section 5.5.1
*
* close frame payload is specially formatted which is checked in CloseInfo
*/
if (frame.getType().getOpCode() == OpCode.CLOSE)
{
ByteBuffer payload = frame.getPayload();
if (payload != null)
{
new CloseInfo(payload,true);
}
}
}
}
public void configureFromExtensions(List exts)
{
// default
this.rsv1InUse = false;
this.rsv2InUse = false;
this.rsv3InUse = false;
// configure from list of extensions in use
for(Extension ext: exts)
{
if (ext.isRsv1User())
{
this.rsv1InUse = true;
}
if (ext.isRsv2User())
{
this.rsv2InUse = true;
}
if (ext.isRsv3User())
{
this.rsv3InUse = true;
}
}
}
/**
* generate a byte buffer based on the frame being passed in
*
* bufferSize is determined by the length of the payload + 28 for frame overhead
*
* @param frame
* @return
*/
public synchronized ByteBuffer generate(Frame frame)
{
int bufferSize = frame.getPayloadLength() + OVERHEAD;
return generate(bufferSize,frame);
}
/**
* Generate, into a ByteBuffer, no more than bufferSize of contents from the frame. If the frame exceeds the bufferSize, then multiple calls to
* {@link #generate(int, WebSocketFrame)} are required to obtain each window of ByteBuffer to complete the frame.
*/
public synchronized ByteBuffer generate(int windowSize, Frame frame)
{
if (windowSize < OVERHEAD)
{
throw new IllegalArgumentException("Cannot have windowSize less than " + OVERHEAD);
}
LOG.debug("{} Generate: {} (windowSize {})",behavior,frame,windowSize);
/*
* prepare the byte buffer to put frame into
*/
ByteBuffer buffer = bufferPool.acquire(windowSize,false);
BufferUtil.clearToFill(buffer);
if (LOG.isDebugEnabled())
{
LOG.debug("Acquired Buffer (windowSize={}): {}",windowSize,BufferUtil.toDetailString(buffer));
}
// since the buffer from the pool can exceed the window size, artificially
// limit the buffer to the window size.
int newlimit = Math.min(buffer.position() + windowSize,buffer.limit());
buffer.limit(newlimit);
LOG.debug("Buffer limited: {}",buffer);
if (frame.remaining() == frame.getPayloadLength())
{
// we need a framing header
assertFrameValid(frame);
/*
* start the generation process
*/
byte b;
// Setup fin thru opcode
b = 0x00;
if (frame.isFin())
{
b |= 0x80; // 1000_0000
}
if (frame.isRsv1())
{
b |= 0x40; // 0100_0000
}
if (frame.isRsv2())
{
b |= 0x20; // 0010_0000
}
if (frame.isRsv3())
{
b |= 0x10;
}
// NOTE: using .getOpCode() here, not .getType().getOpCode() for testing reasons
byte opcode = frame.getOpCode();
if (frame.isContinuation())
{
// Continuations are not the same OPCODE
opcode = OpCode.CONTINUATION;
}
b |= opcode & 0x0F;
buffer.put(b);
// is masked
b = 0x00;
b |= (frame.isMasked()?0x80:0x00);
// payload lengths
int payloadLength = frame.getPayloadLength();
/*
* if length is over 65535 then its a 7 + 64 bit length
*/
if (payloadLength > 0xFF_FF)
{
// we have a 64 bit length
b |= 0x7F;
buffer.put(b); // indicate 8 byte length
buffer.put((byte)0); //
buffer.put((byte)0); // anything over an
buffer.put((byte)0); // int is just
buffer.put((byte)0); // intsane!
buffer.put((byte)((payloadLength >> 24) & 0xFF));
buffer.put((byte)((payloadLength >> 16) & 0xFF));
buffer.put((byte)((payloadLength >> 8) & 0xFF));
buffer.put((byte)(payloadLength & 0xFF));
}
/*
* if payload is ge 126 we have a 7 + 16 bit length
*/
else if (payloadLength >= 0x7E)
{
b |= 0x7E;
buffer.put(b); // indicate 2 byte length
buffer.put((byte)(payloadLength >> 8));
buffer.put((byte)(payloadLength & 0xFF));
}
/*
* we have a 7 bit length
*/
else
{
b |= (payloadLength & 0x7F);
buffer.put(b);
}
// masking key
if (frame.isMasked())
{
buffer.put(frame.getMask());
}
}
// copy payload
if (frame.hasPayload())
{
// remember the position
int maskingStartPosition = buffer.position();
// remember the offset within the frame payload (for working with
// windowed frames that don't split on 4 byte barriers)
int payloadOffset = frame.getPayload().position();
int payloadStart = frame.getPayloadStart();
// put as much as possible into the buffer
BufferUtil.put(frame.getPayload(),buffer);
// mask it if needed
if (frame.isMasked())
{
// move back to remembered position.
int size = buffer.position() - maskingStartPosition;
byte[] mask = frame.getMask();
byte b;
int posBuf;
int posFrame;
for (int i = 0; i < size; i++)
{
posBuf = i + maskingStartPosition;
posFrame = i + (payloadOffset - payloadStart);
// get raw byte from buffer.
b = buffer.get(posBuf);
// mask, using offset information from frame windowing.
b ^= mask[posFrame % 4];
// Mask each byte by its absolute position in the bytebuffer
buffer.put(posBuf,b);
}
}
}
BufferUtil.flipToFlush(buffer,0);
if (LOG.isDebugEnabled())
{
LOG.debug("Generated Buffer: {}",BufferUtil.toDetailString(buffer));
}
return buffer;
}
public ByteBufferPool getBufferPool()
{
return bufferPool;
}
public boolean isRsv1InUse()
{
return rsv1InUse;
}
public boolean isRsv2InUse()
{
return rsv2InUse;
}
public boolean isRsv3InUse()
{
return rsv3InUse;
}
@Override
public String toString()
{
StringBuilder builder = new StringBuilder();
builder.append("Generator[");
builder.append(behavior);
if (validating)
{
builder.append(",validating");
}
if (rsv1InUse)
{
builder.append(",+rsv1");
}
if (rsv2InUse)
{
builder.append(",+rsv2");
}
if (rsv3InUse)
{
builder.append(",+rsv3");
}
builder.append("]");
return builder.toString();
}
}
