public static void checkHeader(ByteBuffer b, int length, int psecret, short step) { int l = b.getInt(); int ps = b.getInt(); int s = b.getShort(); b.getShort(); // the student number, which I am not checking. if (l != length) { System.out.println("Packet length was " + l + " instead of " + length); } if (ps != psecret) { System.out.println("Psecret was " + ps + " instead of " + psecret); } if (s != step) { System.out.println("Packet length was " + s + " instead of " + step); } }
/** * Handles control packet. * * @param data raw packet data that arrived on control PPID. * @param sid SCTP stream id on which the data has arrived. */ private synchronized void onCtrlPacket(byte[] data, int sid) throws IOException { ByteBuffer buffer = ByteBuffer.wrap(data); int messageType = /* 1 byte unsigned integer */ 0xFF & buffer.get(); if (messageType == MSG_CHANNEL_ACK) { if (logger.isDebugEnabled()) { logger.debug(getEndpoint().getID() + " ACK received SID: " + sid); } // Open channel ACK WebRtcDataStream channel = channels.get(sid); if (channel != null) { // Ack check prevents from firing multiple notifications // if we get more than one ACKs (by mistake/bug). if (!channel.isAcknowledged()) { channel.ackReceived(); notifyChannelOpened(channel); } else { logger.warn("Redundant ACK received for SID: " + sid); } } else { logger.error("No channel exists on sid: " + sid); } } else if (messageType == MSG_OPEN_CHANNEL) { int channelType = /* 1 byte unsigned integer */ 0xFF & buffer.get(); int priority = /* 2 bytes unsigned integer */ 0xFFFF & buffer.getShort(); long reliability = /* 4 bytes unsigned integer */ 0xFFFFFFFFL & buffer.getInt(); int labelLength = /* 2 bytes unsigned integer */ 0xFFFF & buffer.getShort(); int protocolLength = /* 2 bytes unsigned integer */ 0xFFFF & buffer.getShort(); String label; String protocol; if (labelLength == 0) { label = ""; } else { byte[] labelBytes = new byte[labelLength]; buffer.get(labelBytes); label = new String(labelBytes, "UTF-8"); } if (protocolLength == 0) { protocol = ""; } else { byte[] protocolBytes = new byte[protocolLength]; buffer.get(protocolBytes); protocol = new String(protocolBytes, "UTF-8"); } if (logger.isDebugEnabled()) { logger.debug( "!!! " + getEndpoint().getID() + " data channel open request on SID: " + sid + " type: " + channelType + " prio: " + priority + " reliab: " + reliability + " label: " + label + " proto: " + protocol); } if (channels.containsKey(sid)) { logger.error("Channel on sid: " + sid + " already exists"); } WebRtcDataStream newChannel = new WebRtcDataStream(sctpSocket, sid, label, true); channels.put(sid, newChannel); sendOpenChannelAck(sid); notifyChannelOpened(newChannel); } else { logger.error("Unexpected ctrl msg type: " + messageType); } }