// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.sdk.internal.websocket;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.chromium.sdk.ConnectionLogger;
import org.chromium.sdk.internal.websocket.ManualLoggingSocketWrapper.LoggableInput;
import org.chromium.sdk.internal.websocket.ManualLoggingSocketWrapper.LoggableOutput;
import org.chromium.sdk.util.BasicUtil;
/**
* WebSocket connection. Sends and receives messages. Implements HyBi-17 protocol specification.
* @see http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17
*/
public class Hybi17WsConnection extends AbstractWsConnection<LoggableInput, LoggableOutput> {
private static final Logger LOGGER = Logger.getLogger(Hybi17WsConnection.class.getName());
private static final Random RANDOM = new Random();
/**
* Specifies how outgoing frames get masked. While protocol specification requires that every
* outgoing frame must be masked (to disable provocative content that socket client may send),
* this doesn't really make sense when the client is trusted. On the other hand, transparent mask
* makes debug sniffering easier.
*/
public enum MaskStrategy {
/**
* Directs to use no mask at all. This is explicitly against protocol specification, peer
* is expected to terminate connection in response.
*/
NO_MASK() {
@Override public byte[] generate() {
return null;
}
@Override
ManualLoggingSocketWrapper.FactoryBase getLogWrapperFactory() {
return ManualLoggingSocketWrapper.PLAIN_ASCII;
}
},
/**
* Directs to always use transparent mask (i.e. all zeroes). This makes all frames clear-text.
* Not suitable when untrusted client uses the WebSocket.
*/
TRANSPARENT_MASK() {
private final byte[] bytes = new byte[4];
@Override public byte[] generate() {
return bytes;
}
@Override
ManualLoggingSocketWrapper.FactoryBase getLogWrapperFactory() {
return ManualLoggingSocketWrapper.PLAIN_ASCII;
}
},
/**
* Directs to use randomly generated masks as specified by specification. As a by-product makes
* traffic hard to sniff.
*/
NORMAL_MASK() {
@Override
byte[] generate() {
byte[] result = new byte[4];
RANDOM.nextBytes(result);
return result;
}
@Override
ManualLoggingSocketWrapper.FactoryBase getLogWrapperFactory() {
return ManualLoggingSocketWrapper.ANNOTATED;
}
};
/** @return 4-byte array or null */
abstract byte[] generate();
abstract ManualLoggingSocketWrapper.FactoryBase getLogWrapperFactory();
}
public static Hybi17WsConnection connect(InetSocketAddress endpoint, int timeout,
String resourceId, MaskStrategy maskStrategy, ConnectionLogger connectionLogger)
throws IOException {
ManualLoggingSocketWrapper socketWrapper = new ManualLoggingSocketWrapper(endpoint, timeout,
connectionLogger, maskStrategy.getLogWrapperFactory());
boolean handshakeDone = false;
Exception handshakeException = null;
try {
performHandshakeOrFail(socketWrapper, endpoint, resourceId);
handshakeDone = true;
} catch (RuntimeException e) {
handshakeException = e;
throw e;
} catch (IOException e) {
handshakeException = e;
throw e;
} finally {
if (!handshakeDone) {
socketWrapper.getShutdownRelay().sendSignal(null, handshakeException);
}
}
return new Hybi17WsConnection(socketWrapper, maskStrategy, connectionLogger);
}
private final MaskStrategy maskStrategy;
private Hybi17WsConnection(ManualLoggingSocketWrapper socketWrapper, MaskStrategy maskStrategy,
ConnectionLogger connectionLogger) {
super(socketWrapper, connectionLogger);
this.maskStrategy = maskStrategy;
}
@Override
public void sendTextualMessage(final String message) throws IOException {
final byte[] bytes = message.getBytes(UTF_8_CHARSET);
LoggablePayload payload = new LoggablePayload() {
@Override void send(LoggableOutput output, byte[] maskBytes) throws IOException {
output.writeToLog(message, "utf-8 demasked");
if (maskBytes != null) {
for (int i = 0; i < bytes.length; i++) {
bytes[i] = (byte) (bytes[i] ^ maskBytes[i % 4]);
}
}
output.writeBytesNoLogging(bytes);
}
@Override int getLength() {
return bytes.length;
}
};
sendMessage(OpCode.TEXT, payload, false);
}
@Override
protected CloseReason runListenLoop(LoggableInput loggableReader)
throws IOException, InterruptedException {
try {
return runListenLoopImpl(loggableReader);
} catch (IOException e) {
String stackTrace = BasicUtil.getStacktraceString(e);
try {
sendClosingMessage(StatusCode.PROTOCOL_ERROR, stackTrace);
} catch (IOException e2) {
// Connection may be closed by this time. We probably don't want to log this exception.
}
throw new IOException(e);
} catch (IncomingProtocolException e) {
String stackTrace = BasicUtil.getStacktraceString(e);
sendClosingMessage(e.getStatusCode(), stackTrace);
throw new IOException(e);
}
}
private CloseReason runListenLoopImpl(LoggableInput loggableReader)
throws IOException, InterruptedException, IncomingProtocolException {
while (true) {
loggableReader.markSeparatorForLog();
int firstByte;
try {
firstByte = loggableReader.readByteOrEos();
} catch (IOException e) {
if (isClosingGracefully()) {
return CloseReason.USER_REQUEST;
} else {
throw e;
}
}
if (firstByte == -1) {
if (isClosingGracefully()) {
return CloseReason.USER_REQUEST;
} else {
return CloseReason.REMOTE_SILENTLY_CLOSED;
}
}
if ((firstByte & FrameBits.FIN_BIT) == 0) {
throw new IncomingProtocolException("Fragments unsupported",
StatusCode.CANNOT_ACCEPT, null);
}
if ((firstByte & FrameBits.RESERVED_MASK) != 0) {
throw new IncomingProtocolException("Unexpected reserved bits",
StatusCode.PROTOCOL_ERROR, null);
}
int opcode = firstByte & FrameBits.OPCODE_MASK;
IncomingFrameHandler frameHandler;
switch (opcode) {
case OpCode.CONTINUATION:
throw new IncomingProtocolException("Continuation is not supported",
StatusCode.CANNOT_ACCEPT, null);
case OpCode.TEXT:
frameHandler = IncomingFrameHandler.TEXT_MESSAGE;
break;
case OpCode.BINARY:
throw new IncomingProtocolException("Binary is not supported",
StatusCode.CANNOT_ACCEPT, null);
case OpCode.CLOSE:
sendClosingMessage(StatusCode.NORMAL, null);
return CloseReason.REMOTE_CLOSE_REQUEST;
case OpCode.PING:
frameHandler = IncomingFrameHandler.PING;
break;
case OpCode.PONG:
frameHandler = IncomingFrameHandler.PONG;
break;
default:
throw new IncomingProtocolException("Unsupported opcode " + opcode,
StatusCode.CANNOT_ACCEPT, null);
}
int secondByte = readByteOfFail(loggableReader);
boolean hasMask = (secondByte & FrameBits.MASK_BIT) != 0;
if (hasMask) {
throw new IncomingProtocolException("Masked server-to-client message is not supported",
StatusCode.PROTOCOL_ERROR, null);
}
int payloadLenByte = secondByte & FrameBits.LENGTH_MASK;
int payloadLen;
if (payloadLenByte == FrameBits.LENGTH_2_BYTE_CODE) {
int lengthTemp = readByteOfFail(loggableReader);
lengthTemp <<= 8;
lengthTemp += readByteOfFail(loggableReader);
payloadLen = lengthTemp;
} else if (payloadLenByte == FrameBits.LENGTH_8_BYTE_CODE) {
for (int i = 0; i < 4; i++) {
int b = readByteOfFail(loggableReader);
if (b != 0) {
throw new IncomingProtocolException("Payload length is too large",
StatusCode.CANNOT_ACCEPT, null);
}
}
int lengthTemp = readByteOfFail(loggableReader);
if ((lengthTemp & FrameBits.HIGH_BIT) != 0) {
throw new IncomingProtocolException("Payload length is too large",
StatusCode.CANNOT_ACCEPT, null);
}
for (int i = 0; i < 3; i++) {
lengthTemp <<= 8;
lengthTemp += readByteOfFail(loggableReader);
}
payloadLen = lengthTemp;
} else {
payloadLen = payloadLenByte;
}
byte [] bytes = loggableReader.readBytes(payloadLen);
frameHandler.process(bytes, this);
}
}
private static class IncomingProtocolException extends Exception {
private final int statusCode;
private IncomingProtocolException(String message, int statusCode, Throwable cause) {
super(message, cause);
this.statusCode = statusCode;
}
int getStatusCode() {
return statusCode;
}
}
private static abstract class IncomingFrameHandler {
abstract void process(byte[] bytes, Hybi17WsConnection hybiWsConnection);
static final IncomingFrameHandler TEXT_MESSAGE = new IncomingFrameHandler() {
@Override
void process(byte[] bytes, Hybi17WsConnection hybiWsConnection) {
final String text = new String(bytes, UTF_8_CHARSET);
hybiWsConnection.getDispatchQueue().add(new MessageDispatcher() {
@Override
boolean dispatch(Listener userListener) {
userListener.textMessageRecieved(text);
return false;
}
});
}
};
static final IncomingFrameHandler PING = new IncomingFrameHandler() {
@Override
void process(final byte[] bytes, Hybi17WsConnection hybiWsConnection) {
LoggablePayload payload = new LoggablePayload() {
@Override
void send(LoggableOutput output, byte[] maskBytes) throws IOException {
output.writeBytesToLog(bytes);
if (maskBytes != null) {
for (int i = 0; i < bytes.length; i++) {
bytes[i] = (byte) (bytes[i] ^ maskBytes[i % 4]);
}
}
output.writeBytes(bytes);
output.markSeparatorForLog();
}
@Override int getLength() {
return bytes.length;
}
};
try {
// Should we do in this thread or relay it to Dispatch thread?
hybiWsConnection.sendMessage(OpCode.PONG, payload, false);
} catch (IOException e) {
LOGGER.log(Level.WARNING, "Failed to send pong", e);
}
}
};
static final IncomingFrameHandler PONG = new IncomingFrameHandler() {
@Override
void process(byte[] bytes, Hybi17WsConnection hybiWsConnection) {
// Ignore
}
};
}
/**
* Payload that can send and properly log itself. Good logging requires that the body
* is not masked.
*/
private static abstract class LoggablePayload {
abstract void send(LoggableOutput output, byte[] maskBytes) throws IOException;
abstract int getLength();
}
private void sendClosingMessage(final int statusCode, final String message) throws IOException {
final byte[] bytes;
if (message == null) {
bytes = new byte[0];
} else {
bytes = message.getBytes(UTF_8_CHARSET);
}
LoggablePayload payload = new LoggablePayload() {
@Override
void send(LoggableOutput output, byte[] maskBytes) throws IOException {
byte codeByte1 = (byte) ((statusCode >> 8) & 0xFF);
byte codeByte2 = (byte) (statusCode & 0xFF);
byte codeByteMasked1 = codeByte1;
byte codeByteMasked2 = codeByte2;
if (maskBytes != null) {
codeByteMasked1 ^= maskBytes[0];
codeByteMasked2 ^= maskBytes[1];
for (int i = 0; i < bytes.length; i++) {
bytes[i] = (byte) (bytes[i] ^ maskBytes[(i + STATUS_CODE_LENTGH) % 4]);
}
}
output.writeByteNoLogging(codeByteMasked1);
output.writeByteNoLogging(codeByteMasked2);
output.writeByteToLog(codeByte1);
output.writeByteToLog(codeByte2);
output.writeBytesNoLogging(bytes);
output.writeToLog(message, "utf-8 demasked");
}
@Override int getLength() {
return STATUS_CODE_LENTGH + bytes.length;
}
};
sendMessage(OpCode.CLOSE, payload, true);
}
private void sendMessage(int opCode, LoggablePayload loggablePayload, boolean isClosingMessage)
throws IOException {
int length = loggablePayload.getLength();
LoggableOutput output = getSocketWrapper().getLoggableOutput();
byte[] maskBytes = maskStrategy.generate();
synchronized (this) {
if (isOutputClosed()) {
throw new IOException("WebSocket is already closed for output");
}
if (isClosingMessage) {
// Close it before actually sending, because we can fail on it.
setOutputClosed(true);
}
byte firstByte = (byte) (FrameBits.FIN_BIT | OpCode.TEXT);
output.writeByte(firstByte);
int maskFlag = maskBytes == null ? 0 : FrameBits.MASK_BIT;
if (length <= 125) {
output.writeByte((byte) (length | maskFlag));
} else if (length <= FrameBits.MAX_TWO_BYTE_INT) {
output.writeByte((byte) (FrameBits.LENGTH_2_BYTE_CODE | maskFlag));
output.writeByte((byte) ((length >> 8) & 0xFF));
output.writeByte((byte) (length & 0xFF));
} else {
output.writeByte((byte) (FrameBits.LENGTH_8_BYTE_CODE | maskFlag));
output.writeByte((byte) 0);
output.writeByte((byte) 0);
output.writeByte((byte) 0);
output.writeByte((byte) 0);
output.writeByte((byte) (length >>> 24));
output.writeByte((byte) ((length >> 16) & 0xFF));
output.writeByte((byte) ((length >> 8) & 0xFF));
output.writeByte((byte) (length & 0xFF));
}
if (maskBytes != null) {
output.writeBytes(maskBytes);
}
loggablePayload.send(output, maskBytes);
}
output.markSeparatorForLog();
}
private static void performHandshakeOrFail(ManualLoggingSocketWrapper socket,
InetSocketAddress endpoint, String resourceId) throws IOException {
Hybi17Handshake.Result result =
Hybi17Handshake.performHandshake(socket, endpoint, resourceId, RANDOM);
result.accept(HANDSHAKE_RESULT_VISITOR).get();
}
private static final Hybi17Handshake.Result.Visitor<DataOrException<Void>>
HANDSHAKE_RESULT_VISITOR =
new Hybi17Handshake.Result.Visitor<DataOrException<Void>>() {
@Override
public DataOrException<Void> visitConnected() {
return new DataOrException<Void>() {
@Override Void get() throws IOException {
return null;
}
};
}
@Override
public DataOrException<Void> visitUnknownError(final Exception exception) {
return new DataOrException<Void>() {
@Override Void get() throws IOException {
throw new IOException("Failed to establish WebSocket connection", exception);
}
};
}
@Override
public DataOrException<Void> visitErrorMessage(final int code,
final String errorName, final String text) {
return new DataOrException<Void>() {
@Override Void get() throws IOException {
throw new IOException("Failed to establish WebSocket connection: " + code + " " +
errorName + " | " + text);
}
};
}
};
/**
* This class is used solely to put IOException through Visitor.
*/
private static abstract class DataOrException<T> {
abstract T get() throws IOException;
}
private static int readByteOfFail(LoggableInput loggableReader) throws IOException {
int b = loggableReader.readByteOrEos();
if (b == -1) {
throw new IOException("Unexpected EOS");
}
return b;
}
private interface FrameBits {
// First byte bits.
int FIN_BIT = 1 << 7;
int MASK_BIT = 1 << 7;
// Second byte bits.
int OPCODE_LENGTH = 4;
int OPCODE_MASK = (1 << OPCODE_LENGTH) - 1;
int RESERVED_MASK = ((1 << 3) - 1) << OPCODE_LENGTH ;
int LENGTH_MASK = (1 << 7) - 1;
int LENGTH_2_BYTE_CODE = 126;
int LENGTH_8_BYTE_CODE = 127;
// Length bytes.
int HIGH_BIT = 1 << 7;
int MAX_TWO_BYTE_INT = 1 << 16 - 1;
}
private interface OpCode {
int CONTINUATION = 0x0;
int TEXT = 0x1;
int BINARY = 0x2;
int CLOSE = 0x8;
int PING = 0x9;
int PONG = 0xA;
}
private interface StatusCode {
int NORMAL = 1000;
int PROTOCOL_ERROR = 1002;
int CANNOT_ACCEPT = 1003;
}
private static final int STATUS_CODE_LENTGH = 2;
}