org.apache.catalina.websocket.WsFrame Maven / Gradle / Ivy
/*
* 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.catalina.websocket;
import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CoderResult;
import org.apache.catalina.util.Conversions;
import org.apache.coyote.http11.upgrade.UpgradeProcessor;
import org.apache.tomcat.util.res.StringManager;
/**
* Represents a complete WebSocket frame with the exception of the payload for
* non-control frames.
*/
public class WsFrame {
private static final StringManager sm =
StringManager.getManager(Constants.Package);
private final boolean fin;
private final int rsv;
private final byte opCode;
private byte[] mask = new byte[4];
private long payloadLength;
private ByteBuffer payload;
/**
* Create the new WebSocket frame, reading data from the processor as
* necessary.
*
* @param first First byte of data for this frame
* @param processor Processor associated with the WebSocket connection on
* which the frame has been sent
*
* @throws IOException If a problem occurs processing the frame. Any
* exception will trigger the closing of the WebSocket
* connection.
*/
private WsFrame(byte first,
UpgradeProcessor processor) throws IOException {
int b = first & 0xFF;
fin = (b & 0x80) > 0;
rsv = (b & 0x70) >>> 4;
opCode = (byte) (b & 0x0F);
b = blockingRead(processor);
// Client data must be masked
if ((b & 0x80) == 0) {
throw new IOException(sm.getString("frame.notMasked"));
}
payloadLength = b & 0x7F;
if (payloadLength == 126) {
byte[] extended = new byte[2];
blockingRead(processor, extended);
payloadLength = Conversions.byteArrayToLong(extended);
} else if (payloadLength == 127) {
byte[] extended = new byte[8];
blockingRead(processor, extended);
payloadLength = Conversions.byteArrayToLong(extended);
}
if (isControl()) {
if (payloadLength > 125) {
throw new IOException();
}
if (!fin) {
throw new IOException();
}
}
blockingRead(processor, mask);
if (isControl()) {
// Note: Payload limited to <= 125 bytes by test above
payload = ByteBuffer.allocate((int) payloadLength);
blockingRead(processor, payload);
if (opCode == Constants.OPCODE_CLOSE && payloadLength > 2) {
// Check close payload - if present - is valid UTF-8
CharBuffer cb = CharBuffer.allocate((int) payloadLength);
Utf8Decoder decoder = new Utf8Decoder();
payload.position(2);
CoderResult cr = decoder.decode(payload, cb, true);
payload.position(0);
if (cr.isError()) {
throw new IOException(sm.getString("frame.invalidUtf8"));
}
}
} else {
payload = null;
}
}
public boolean getFin() {
return fin;
}
public int getRsv() {
return rsv;
}
public byte getOpCode() {
return opCode;
}
public boolean isControl() {
return (opCode & 0x08) > 0;
}
public byte[] getMask() {
return mask;
}
public long getPayLoadLength() {
return payloadLength;
}
public ByteBuffer getPayLoad() {
return payload;
}
/*
* Blocks until a aingle byte has been read
*/
private int blockingRead(UpgradeProcessor processor)
throws IOException {
int result = processor.read();
if (result == -1) {
throw new IOException(sm.getString("frame.eos"));
}
return result;
}
/*
* Blocks until the byte array has been filled.
*/
private void blockingRead(UpgradeProcessor processor, byte[] bytes)
throws IOException {
int read = 0;
int last = 0;
while (read < bytes.length) {
last = processor.read(true, bytes, read, bytes.length - read);
if (last == -1) {
throw new IOException(sm.getString("frame.eos"));
}
read += last;
}
}
/*
* Intended to read whole payload and blocks until it has. Therefore able to
* unmask the payload data.
*/
private void blockingRead(UpgradeProcessor processor, ByteBuffer bb)
throws IOException {
int last = 0;
while (bb.hasRemaining()) {
last = processor.read();
if (last == -1) {
throw new IOException(sm.getString("frame.eos"));
}
bb.put((byte) (last ^ mask[bb.position() % 4]));
}
bb.flip();
}
/**
* Read the next WebSocket frame, reading data from the processor as
* necessary.
*
* @param processor Processor associated with the WebSocket connection on
* which the frame has been sent
*
* @param block Should this method block until a frame is presented if no
* data is currently available to process. Note that is a
* single byte is available, this method will block until the
* complete frame (excluding payload for non-control frames) is
* available.
*
* @throws IOException If a problem occurs processing the frame. Any
* exception will trigger the closing of the WebSocket
* connection.
*/
public static WsFrame nextFrame(UpgradeProcessor processor,
boolean block) throws IOException {
byte[] first = new byte[1];
int read = processor.read(block, first, 0, 1);
if (read == 1) {
return new WsFrame(first[0], processor);
} else if (read == 0) {
return null;
} else if (read == -1) {
throw new EOFException(sm.getString("frame.readEos"));
} else {
throw new IOException(
sm.getString("frame.readFailed", Integer.valueOf(read)));
}
}
}