/*
* 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.tomcat.websocket;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
import javax.websocket.CloseReason;
import javax.websocket.CloseReason.CloseCodes;
import javax.websocket.MessageHandler;
import javax.websocket.PongMessage;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.buf.Utf8Decoder;
import org.apache.tomcat.util.res.StringManager;
/**
* Takes the ServletInputStream, processes the WebSocket frames it contains and
* extracts the messages. WebSocket Pings received will be responded to
* automatically without any action required by the application.
*/
public abstract class WsFrameBase {
private static final StringManager sm =
StringManager.getManager(Constants.PACKAGE_NAME);
// Connection level attributes
protected final WsSession wsSession;
protected final byte[] inputBuffer;
// Attributes for control messages
// Control messages can appear in the middle of other messages so need
// separate attributes
private final ByteBuffer controlBufferBinary = ByteBuffer.allocate(125);
private final CharBuffer controlBufferText = CharBuffer.allocate(125);
// Attributes of the current message
private final CharsetDecoder utf8DecoderControl = new Utf8Decoder().
onMalformedInput(CodingErrorAction.REPORT).
onUnmappableCharacter(CodingErrorAction.REPORT);
private final CharsetDecoder utf8DecoderMessage = new Utf8Decoder().
onMalformedInput(CodingErrorAction.REPORT).
onUnmappableCharacter(CodingErrorAction.REPORT);
private boolean continuationExpected = false;
private boolean textMessage = false;
private ByteBuffer messageBufferBinary;
private CharBuffer messageBufferText;
// Attributes of the current frame
private boolean fin = false;
private int rsv = 0;
private byte opCode = 0;
private final byte[] mask = new byte[4];
private int maskIndex = 0;
private long payloadLength = 0;
private long payloadWritten = 0;
// Attributes tracking state
private State state = State.NEW_FRAME;
private volatile boolean open = true;
private int readPos = 0;
protected int writePos = 0;
public WsFrameBase(WsSession wsSession) {
inputBuffer = new byte[Constants.DEFAULT_BUFFER_SIZE];
messageBufferBinary =
ByteBuffer.allocate(wsSession.getMaxBinaryMessageBufferSize());
messageBufferText =
CharBuffer.allocate(wsSession.getMaxTextMessageBufferSize());
this.wsSession = wsSession;
}
protected void processInputBuffer() throws IOException {
while (true) {
wsSession.updateLastActive();
if (state == State.NEW_FRAME) {
if (!processInitialHeader()) {
break;
}
// If a close frame has been received, no further data should
// have seen
if (!open) {
throw new IOException(sm.getString("wsFrame.closed"));
}
}
if (state == State.PARTIAL_HEADER) {
if (!processRemainingHeader()) {
break;
}
}
if (state == State.DATA) {
if (!processData()) {
break;
}
}
}
}
/**
* @return <code>true</code> if sufficient data was present to process all
* of the initial header
*/
private boolean processInitialHeader() throws IOException {
// Need at least two bytes of data to do this
if (writePos - readPos < 2) {
return false;
}
int b = inputBuffer[readPos++];
fin = (b & 0x80) > 0;
rsv = (b & 0x70) >>> 4;
if (rsv != 0) {
// Note extensions may use rsv bits but currently no extensions are
// supported
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.wrongRsv", Integer.valueOf(rsv))));
}
opCode = (byte) (b & 0x0F);
if (Util.isControl(opCode)) {
if (!fin) {
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.controlFragmented")));
}
if (opCode != Constants.OPCODE_PING &&
opCode != Constants.OPCODE_PONG &&
opCode != Constants.OPCODE_CLOSE) {
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.invalidOpCode",
Integer.valueOf(opCode))));
}
} else {
if (continuationExpected) {
if (opCode != Constants.OPCODE_CONTINUATION) {
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.noContinuation")));
}
} else {
try {
if (opCode == Constants.OPCODE_BINARY) {
// New binary message
textMessage = false;
int size = wsSession.getMaxBinaryMessageBufferSize();
if (size != messageBufferBinary.capacity()) {
messageBufferBinary = ByteBuffer.allocate(size);
}
} else if (opCode == Constants.OPCODE_TEXT) {
// New text message
textMessage = true;
int size = wsSession.getMaxTextMessageBufferSize();
if (size != messageBufferText.capacity()) {
messageBufferText = CharBuffer.allocate(size);
}
} else {
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.invalidOpCode",
Integer.valueOf(opCode))));
}
} catch (IllegalStateException ise) {
// Thrown if the session is already closed
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.sessionClosed")));
}
}
continuationExpected = !fin;
}
b = inputBuffer[readPos++];
// Client data must be masked
if ((b & 0x80) == 0 && isMasked()) {
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.notMasked")));
}
payloadLength = b & 0x7F;
state = State.PARTIAL_HEADER;
return true;
}
protected abstract boolean isMasked();
/**
* @return <code>true</code> if sufficient data was present to complete the
* processing of the header
*/
private boolean processRemainingHeader() throws IOException {
// Ignore the 2 bytes already read. 4 for the mask
int headerLength;
if (isMasked()) {
headerLength = 4;
} else {
headerLength = 0;
}
// Add additional bytes depending on length
if (payloadLength == 126) {
headerLength += 2;
} else if (payloadLength == 127) {
headerLength += 8;
}
if (writePos - readPos < headerLength) {
return false;
}
// Calculate new payload length if necessary
if (payloadLength == 126) {
payloadLength = byteArrayToLong(inputBuffer, readPos, 2);
readPos += 2;
} else if (payloadLength == 127) {
payloadLength = byteArrayToLong(inputBuffer, readPos, 8);
readPos += 8;
}
if (Util.isControl(opCode)) {
if (payloadLength > 125) {
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.controlPayloadTooBig",
Long.valueOf(payloadLength))));
}
if (!fin) {
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.controlNoFin")));
}
}
if (isMasked()) {
System.arraycopy(inputBuffer, readPos, mask, 0, 4);
readPos += 4;
}
state = State.DATA;
return true;
}
private boolean processData() throws IOException {
checkRoomPayload();
if (Util.isControl(opCode)) {
return processDataControl();
} else if (textMessage) {
return processDataText();
} else {
return processDataBinary();
}
}
private boolean processDataControl() throws IOException {
if (!appendPayloadToMessage(controlBufferBinary)) {
return false;
}
controlBufferBinary.flip();
if (opCode == Constants.OPCODE_CLOSE) {
open = false;
String reason = null;
int code = CloseCodes.NORMAL_CLOSURE.getCode();
if (controlBufferBinary.remaining() == 1) {
controlBufferBinary.clear();
// Payload must be zero or greater than 2
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.oneByteCloseCode")));
}
if (controlBufferBinary.remaining() > 1) {
code = controlBufferBinary.getShort();
if (controlBufferBinary.remaining() > 0) {
CoderResult cr = utf8DecoderControl.decode(
controlBufferBinary, controlBufferText, true);
if (cr.isError()) {
controlBufferBinary.clear();
controlBufferText.clear();
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.invalidUtf8Close")));
}
// There will be no overflow as the output buffer is big
// enough. There will be no underflow as all the data is
// passed to the decoder in a single call.
controlBufferText.flip();
reason = controlBufferText.toString();
}
}
wsSession.onClose(new CloseReason(Util.getCloseCode(code), reason));
} else if (opCode == Constants.OPCODE_PING) {
if (wsSession.isOpen()) {
wsSession.getBasicRemote().sendPong(controlBufferBinary);
}
} else if (opCode == Constants.OPCODE_PONG) {
MessageHandler.Whole<PongMessage> mhPong =
wsSession.getPongMessageHandler();
if (mhPong != null) {
try {
mhPong.onMessage(new WsPongMessage(controlBufferBinary));
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
wsSession.getLocal().onError(wsSession, t);
} finally {
controlBufferBinary.clear();
}
}
} else {
// Should have caught this earlier but just in case...
controlBufferBinary.clear();
throw new WsIOException(new CloseReason(
CloseCodes.PROTOCOL_ERROR,
sm.getString("wsFrame.invalidOpCode",
Integer.valueOf(opCode))));
}
controlBufferBinary.clear();
newFrame();
return true;
}
@SuppressWarnings("unchecked")
private void sendMessageText(boolean last) throws WsIOException {
MessageHandler mh = wsSession.getTextMessageHandler();
if (mh != null) {
if (mh instanceof WrappedMessageHandler) {
long maxMessageSize =
((WrappedMessageHandler) mh).getMaxMessageSize();
if (maxMessageSize > -1 &&
messageBufferText.remaining() > maxMessageSize) {
throw new WsIOException(new CloseReason(CloseCodes.TOO_BIG,
sm.getString("wsFrame.messageTooBig",
Long.valueOf(messageBufferText.remaining()),
Long.valueOf(maxMessageSize))));
}
}
try {
if (mh instanceof MessageHandler.Partial<?>) {
((MessageHandler.Partial<String>) mh).onMessage(
messageBufferText.toString(), last);
} else {
// Caller ensures last == true if this branch is used
((MessageHandler.Whole<String>) mh).onMessage(
messageBufferText.toString());
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
wsSession.getLocal().onError(wsSession, t);
} finally {
messageBufferText.clear();
}
}
}
private boolean processDataText() throws IOException {
// Copy the available data to the buffer
while (!appendPayloadToMessage(messageBufferBinary)) {
// Frame not complete - we ran out of something
// Convert bytes to UTF-8
messageBufferBinary.flip();
while (true) {
CoderResult cr = utf8DecoderMessage.decode(
messageBufferBinary, messageBufferText, false);
if (cr.isError()) {
throw new WsIOException(new CloseReason(
CloseCodes.NOT_CONSISTENT,
sm.getString("wsFrame.invalidUtf8")));
} else if (cr.isOverflow()) {
// Ran out of space in text buffer - flush it
if (usePartial()) {
messageBufferText.flip();
sendMessageText(false);
messageBufferText.clear();
} else {
throw new WsIOException(new CloseReason(
CloseCodes.TOO_BIG,
sm.getString("wsFrame.textMessageTooBig")));
}
} else if (cr.isUnderflow()) {
// Need more input
// Compact what we have to create as much space as possible
messageBufferBinary.compact();
// What did we run out of?
if (readPos == writePos) {
// Ran out of input data - get some more
return false;
} else {
// Ran out of message buffer - exit inner loop and
// refill
break;
}
}
}
}
messageBufferBinary.flip();
boolean last = false;
// Frame is fully received
// Convert bytes to UTF-8
while (true) {
CoderResult cr = utf8DecoderMessage.decode(messageBufferBinary,
messageBufferText, last);
if (cr.isError()) {
throw new WsIOException(new CloseReason(
CloseCodes.NOT_CONSISTENT,
sm.getString("wsFrame.invalidUtf8")));
} else if (cr.isOverflow()) {
// Ran out of space in text buffer - flush it
if (usePartial()) {
messageBufferText.flip();
sendMessageText(false);
messageBufferText.clear();
} else {
throw new WsIOException(new CloseReason(
CloseCodes.TOO_BIG,
sm.getString("wsFrame.textMessageTooBig")));
}
} else if (cr.isUnderflow() & !last) {
// End of frame and possible message as well.
if (continuationExpected) {
// If partial messages are supported, send what we have
// managed to decode
if (usePartial()) {
messageBufferText.flip();
sendMessageText(false);
messageBufferText.clear();
}
messageBufferBinary.compact();
newFrame();
// Process next frame
return true;
} else {
// Make sure coder has flushed all output
last = true;
}
} else {
// End of message
messageBufferText.flip();
sendMessageText(true);
newMessage();
return true;
}
}
}
private boolean processDataBinary() throws IOException {
// Copy the available data to the buffer
while (!appendPayloadToMessage(messageBufferBinary)) {
// Frame not complete - what did we run out of?
if (readPos == writePos) {
// Ran out of input data - get some more
return false;
} else {
// Ran out of message buffer - flush it
if (!usePartial()) {
CloseReason cr = new CloseReason(CloseCodes.TOO_BIG,
sm.getString("wsFrame.bufferTooSmall",
Integer.valueOf(
messageBufferBinary.capacity()),
Long.valueOf(payloadLength)));
throw new WsIOException(cr);
}
messageBufferBinary.flip();
ByteBuffer copy =
ByteBuffer.allocate(messageBufferBinary.limit());
copy.put(messageBufferBinary);
copy.flip();
sendMessageBinary(copy, false);
messageBufferBinary.clear();
}
}
// Frame is fully received
// Send the message if either:
// - partial messages are supported
// - the message is complete
if (usePartial() || !continuationExpected) {
messageBufferBinary.flip();
ByteBuffer copy =
ByteBuffer.allocate(messageBufferBinary.limit());
copy.put(messageBufferBinary);
copy.flip();
sendMessageBinary(copy, !continuationExpected);
messageBufferBinary.clear();
}
if (continuationExpected) {
// More data for this message expected, start a new frame
newFrame();
} else {
// Message is complete, start a new message
newMessage();
}
return true;
}
@SuppressWarnings("unchecked")
private void sendMessageBinary(ByteBuffer msg, boolean last)
throws WsIOException {
MessageHandler mh = wsSession.getBinaryMessageHandler();
if (mh != null) {
if (mh instanceof WrappedMessageHandler) {
long maxMessageSize =
((WrappedMessageHandler) mh).getMaxMessageSize();
if (maxMessageSize > -1 && msg.remaining() > maxMessageSize) {
throw new WsIOException(new CloseReason(CloseCodes.TOO_BIG,
sm.getString("wsFrame.messageTooBig",
Long.valueOf(msg.remaining()),
Long.valueOf(maxMessageSize))));
}
}
try {
if (mh instanceof MessageHandler.Partial<?>) {
((MessageHandler.Partial<ByteBuffer>) mh).onMessage(msg, last);
} else {
// Caller ensures last == true if this branch is used
((MessageHandler.Whole<ByteBuffer>) mh).onMessage(msg);
}
} catch(Throwable t) {
ExceptionUtils.handleThrowable(t);
wsSession.getLocal().onError(wsSession, t);
}
}
}
private void newMessage() {
messageBufferBinary.clear();
messageBufferText.clear();
utf8DecoderMessage.reset();
continuationExpected = false;
newFrame();
}
private void newFrame() {
if (readPos == writePos) {
readPos = 0;
writePos = 0;
}
maskIndex = 0;
payloadWritten = 0;
state = State.NEW_FRAME;
// These get reset in processInitialHeader()
// fin, rsv, opCode, payloadLength, mask
checkRoomHeaders();
}
private void checkRoomHeaders() {
// Is the start of the current frame too near the end of the input
// buffer?
if (inputBuffer.length - readPos < 131) {
// Limit based on a control frame with a full payload
makeRoom();
}
}
private void checkRoomPayload() {
if (inputBuffer.length - readPos - payloadLength + payloadWritten < 0) {
makeRoom();
}
}
private void makeRoom() {
System.arraycopy(inputBuffer, readPos, inputBuffer, 0,
writePos - readPos);
writePos = writePos - readPos;
readPos = 0;
}
private boolean usePartial() {
if (Util.isControl(opCode)) {
return false;
} else if (textMessage) {
MessageHandler mh = wsSession.getTextMessageHandler();
if (mh != null) {
return mh instanceof MessageHandler.Partial<?>;
}
return false;
} else {
// Must be binary
MessageHandler mh = wsSession.getBinaryMessageHandler();
if (mh != null) {
return mh instanceof MessageHandler.Partial<?>;
}
return false;
}
}
private boolean appendPayloadToMessage(ByteBuffer dest) {
if (isMasked()) {
while (payloadWritten < payloadLength && readPos < writePos &&
dest.hasRemaining()) {
byte b = (byte) ((inputBuffer[readPos] ^ mask[maskIndex]) & 0xFF);
maskIndex++;
if (maskIndex == 4) {
maskIndex = 0;
}
readPos++;
payloadWritten++;
dest.put(b);
}
return (payloadWritten == payloadLength);
} else {
long toWrite = Math.min(
payloadLength - payloadWritten, writePos - readPos);
toWrite = Math.min(toWrite, dest.remaining());
dest.put(inputBuffer, readPos, (int) toWrite);
readPos += toWrite;
payloadWritten += toWrite;
return (payloadWritten == payloadLength);
}
}
protected static long byteArrayToLong(byte[] b, int start, int len)
throws IOException {
if (len > 8) {
throw new IOException(sm.getString("wsFrame.byteToLongFail",
Long.valueOf(len)));
}
int shift = 0;
long result = 0;
for (int i = start + len - 1; i >= start; i--) {
result = result + ((b[i] & 0xFF) << shift);
shift += 8;
}
return result;
}
protected boolean isOpen() {
return open;
}
private static enum State {
NEW_FRAME, PARTIAL_HEADER, DATA
}
}