/**
* BigBlueButton open source conferencing system - http://www.bigbluebutton.org/
*
* Copyright (c) 2012 BigBlueButton Inc. and by respective authors (see below).
*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation; either version 3.0 of the License, or (at your option) any later
* version.
*
* BigBlueButton is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along
* with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
*
*/
package org.bigbluebutton.app.screenshare.server.socket;
import java.awt.Point;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.util.Arrays;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.CumulativeProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.bigbluebutton.app.screenshare.server.messages.CaptureEndMessage;
import org.bigbluebutton.app.screenshare.server.messages.CaptureStartMessage;
import org.bigbluebutton.app.screenshare.server.messages.CaptureUpdateMessage;
import org.bigbluebutton.app.screenshare.server.messages.MouseLocationMessage;
import org.bigbluebutton.app.screenshare.server.session.Dimension;
import org.red5.logging.Red5LoggerFactory;
import org.slf4j.Logger;
public class BlockStreamProtocolDecoder extends CumulativeProtocolDecoder {
final private Logger log = Red5LoggerFactory.getLogger(BlockStreamProtocolDecoder.class, "screenshare");
private static final String ROOM = "ROOM";
private static final byte[] POLICY_REQUEST = new byte[] {'<','p','o','l','i','c','y','-','f','i','l','e','-','r','e','q','u','e','s','t','/','>',0};
private static final byte[] END_FRAME = new byte[] {'S', 'S', '-', 'E', 'N', 'D'};
private static final byte[] HEADER = new byte[] {'B', 'B', 'B', '-', 'S', 'S'};
private static final byte CAPTURE_START_EVENT = 0;
private static final byte CAPTURE_UPDATE_EVENT = 1;
private static final byte CAPTURE_END_EVENT = 2;
private static final byte MOUSE_LOCATION_EVENT = 3;
protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
// Remember the initial position.
int start = in.position();
byte[] endFrame = new byte[END_FRAME.length];
// Now find the END FRAME delimeter in the buffer.
int curpos = 0;
while (in.remaining() >= END_FRAME.length) {
curpos = in.position();
in.get(endFrame);
if (Arrays.equals(endFrame, END_FRAME)) {
//log.debug("***** END FRAME {} = {}", endFrame, END_FRAME);
// Remember the current position and limit.
int position = in.position();
int limit = in.limit();
try {
in.position(start);
in.limit(position);
// The bytes between in.position() and in.limit()
// now contain a full frame.
parseFrame(session, in.slice(), out);
} finally {
// Set the position to point right after the
// detected END FRAME and set the limit to the old
// one.
in.position(position);
in.limit(limit);
}
return true;
}
in.position(curpos+1);
}
// Try to find a policy request, used by the BigBlueButton Client Checker
in.position(start);
if (tryToParsePolicyRequest(session, in, out)) {
return true;
}
// Could not find END FRAME in the buffer. Reset the initial
// position to the one we recorded above.
in.position(start);
return false;
}
private boolean tryToParsePolicyRequest(IoSession session, IoBuffer in, ProtocolDecoderOutput out) {
byte[] message = new byte[POLICY_REQUEST.length];
if (in.remaining() >= POLICY_REQUEST.length) {
in.get(message, 0, message.length);
if (Arrays.equals(message, POLICY_REQUEST)) {
log.debug("Sending cross domain policy to the user");
IoBuffer buffer = IoBuffer.allocate(8);
buffer.setAutoExpand(true);
try {
buffer.putString("<cross-domain-policy><allow-access-from domain=\"*\" to-ports=\"*\" /></cross-domain-policy>", Charset.forName("UTF-8").newEncoder());
buffer.put((byte) 0);
} catch (CharacterCodingException e) {
e.printStackTrace();
return false;
}
buffer.flip();
session.write(buffer);
return true;
}
}
return false;
}
private void parseFrame(IoSession session, IoBuffer in, ProtocolDecoderOutput out) {
//log.debug("Frame = {}", in.toString());
try {
byte[] header = new byte[HEADER.length];
in.get(header, 0, HEADER.length);
if (! Arrays.equals(header, HEADER)) {
log.info("Invalid header. Discarding. {}", header);
return;
}
int messageLength = in.getInt();
if (in.remaining() < messageLength) {
log.info("Invalid length. Discarding. [{} < {}]", in.remaining(), messageLength);
return;
}
decodeMessage(session, in, out);
return;
} catch (Exception e) {
log.warn("Failed to parse frame. Discarding.");
}
}
private void decodeMessage(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
byte event = in.get();
switch (event) {
case CAPTURE_START_EVENT:
log.info("Decoding CAPTURE_START_EVENT");
decodeCaptureStartEvent(session, in, out);
break;
case CAPTURE_UPDATE_EVENT:
//log.info("Decoding CAPTURE_UPDATE_EVENT");
decodeCaptureUpdateEvent(session, in, out);
break;
case CAPTURE_END_EVENT:
log.info("Got CAPTURE_END_EVENT event: " + event);
decodeCaptureEndEvent(session, in, out);
break;
case MOUSE_LOCATION_EVENT:
decodeMouseLocationEvent(session, in, out);
break;
default:
log.error("Unknown event: " + event);
throw new Exception("Unknown event: " + event);
}
}
private void decodeMouseLocationEvent(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
String room = decodeRoom(session, in);
if ("".equals(room)) {
log.warn("Empty meeting name in decoding mouse location.");
throw new Exception("Empty meeting name in decoding mouse location.");
}
int seqNum = in.getInt();
int mouseX = in.getInt();
int mouseY = in.getInt();
/** Swallow end frame **/
in.get(new byte[END_FRAME.length]);
MouseLocationMessage event = new MouseLocationMessage(room, new Point(mouseX, mouseY), seqNum);
out.write(event);
}
private void decodeCaptureEndEvent(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
String room = decodeRoom(session, in);
if ("".equals(room)) {
log.warn("Empty meeting name in decoding capture end event.");
throw new Exception("Empty meeting name in decoding capture end event.");
}
log.info("CaptureEndEvent for " + room);
int seqNum = in.getInt();
/** Swallow end frame **/
in.get(new byte[END_FRAME.length]);
CaptureEndMessage event = new CaptureEndMessage(room, seqNum);
out.write(event);
}
private void decodeCaptureStartEvent(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
String room = decodeRoom(session, in);
if ("".equals(room)) {
log.warn("Empty meeting name in decoding capture start event.");
throw new Exception("Empty meeting name in decoding capture start event.");
}
session.setAttribute(ROOM, room);
int seqNum = in.getInt();
Dimension blockDim = decodeDimension(in);
Dimension screenDim = decodeDimension(in);
boolean useSVC2 = (in.get() == 1);
/** Swallow end frame **/
in.get(new byte[END_FRAME.length]);
log.info("CaptureStartEvent for " + room);
CaptureStartMessage event = new CaptureStartMessage(room, screenDim, blockDim, seqNum, useSVC2);
out.write(event);
}
private Dimension decodeDimension(IoBuffer in) {
int width = in.getInt();
int height = in.getInt();
return new Dimension(width, height);
}
private String decodeRoom(IoSession session, IoBuffer in) {
int roomLength = in.get();
// System.out.println("Room length = " + roomLength);
String room = "";
try {
room = in.getString(roomLength, Charset.forName( "UTF-8" ).newDecoder());
if (session.containsAttribute(ROOM)) {
String attRoom = (String) session.getAttribute(ROOM);
if (!attRoom.equals(room)) {
log.warn(room + " is not the same as room in attribute [" + attRoom + "]");
}
}
} catch (CharacterCodingException e) {
log.error(e.getMessage());
}
return room;
}
private void decodeCaptureUpdateEvent(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
String room = decodeRoom(session, in);
if ("".equals(room)) {
log.warn("Empty meeting name in decoding capture start event.");
throw new Exception("Empty meeting name in decoding capture start event.");
}
int seqNum = in.getInt();
int numBlocks = in.getShort();
String blocksStr = "Blocks changed ";
for (int i = 0; i < numBlocks; i++) {
int position = in.getShort();
blocksStr += " " + position;
boolean isKeyFrame = (in.get() == 1) ? true : false;
int length = in.getInt();
byte[] data = new byte[length];
in.get(data, 0, length);
CaptureUpdateMessage event = new CaptureUpdateMessage(room, position, data, isKeyFrame, seqNum);
out.write(event);
}
/** Swallow end frame **/
in.get(new byte[END_FRAME.length]);
}
}