/*
* Copyright (C) 2008-2013 Team XBMC
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.xbmc.kore.eventclient;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
/**
* XBMC Event Client Class
* <p>
* Implementation of XBMC's UDP based input system.
* A set of classes that abstract the various packets that the event server
* currently supports. In addition, there's also a class, XBMCClient, that
* provides functions that sends the various packets. Use XBMCClient if you
* don't need complete control over packet structure.
* </p>
* <p>
* The basic workflow involves:
* <ol>
* <li>Send a HELO packet</li>
* <li>Send x number of valid packets</li>
* <li>Send a BYE packet</li>
* </ol>
* </p>
* <p>
* IMPORTANT NOTE ABOUT TIMEOUTS:
* A client is considered to be timed out if XBMC doesn't received a packet
* at least once every 60 seconds. To "ping" XBMC with an empty packet use
* PacketPING or XBMCClient.ping(). See the documentation for details.
* </p>
* <p>
* Base class that implements a single event packet.
* - Generic packet structure (maximum 1024 bytes per packet)
* - Header is 32 bytes long, so 992 bytes available for payload
* - large payloads can be split into multiple packets using H4 and H5
* H5 should contain total no. of packets in such a case
* - H6 contains length of P1, which is limited to 992 bytes
* - if H5 is 0 or 1, then H4 will be ignored (single packet msg)
* - H7 must be set to zeros for now
* </p>
* <pre>
* -----------------------------
* | -H1 Signature ("XBMC") | - 4 x CHAR 4B
* | -H2 Version (eg. 2.0) | - 2 x UNSIGNED CHAR 2B
* | -H3 PacketType | - 1 x UNSIGNED SHORT 2B
* | -H4 Sequence number | - 1 x UNSIGNED LONG 4B
* | -H5 No. of packets in msg | - 1 x UNSIGNED LONG 4B
* | -H6 Payloadsize of packet | - 1 x UNSIGNED SHORT 2B
* | -H7 Client's unique token | - 1 x UNSIGNED LONG 4B
* | -H8 Reserved | - 10 x UNSIGNED CHAR 10B
* |---------------------------|
* | -P1 payload | -
* -----------------------------
* </pre>
* @author Stefan Agner
*
*/
public abstract class Packet {
private byte[] sig;
private byte[] payload = new byte[0];
private byte minver;
private byte majver;
private short packettype;
private final static short MAX_PACKET_SIZE = 1024;
private final static short HEADER_SIZE = 32;
private final static short MAX_PAYLOAD_SIZE = MAX_PACKET_SIZE - HEADER_SIZE;
protected final static byte PT_HELO = 0x01;
protected final static byte PT_BYE = 0x02;
protected final static byte PT_BUTTON = 0x03;
protected final static byte PT_MOUSE = 0x04;
protected final static byte PT_PING = 0x05;
protected final static byte PT_BROADCAST = 0x06;
protected final static byte PT_NOTIFICATION = 0x07;
protected final static byte PT_BLOB = 0x08;
protected final static byte PT_LOG = 0x09;
protected final static byte PT_ACTION = 0x0A;
protected final static byte PT_DEBUG = (byte)0xFF;
public final static byte ICON_NONE = 0x00;
public final static byte ICON_JPEG = 0x01;
public final static byte ICON_PNG = 0x02;
public final static byte ICON_GIF = 0x03;
private static int uid = (int)(Math.random()*Integer.MAX_VALUE);
/**
* This is an Abstract class and cannot be instanced. Please use one of the Packet implementation Classes
* (PacketXXX).
*
* Implements an XBMC Event Client Packet. Type is to be specified at creation time, Payload can be added
* with the various appendPayload methods. Packet can be sent through UDP-Socket with method "send".
* @param packettype Type of Packet (PT_XXX)
*/
protected Packet(short packettype)
{
sig = new byte[] {'X', 'B', 'M', 'C' };
minver = 0;
majver = 2;
this.packettype = packettype;
}
/**
* Appends a String to the payload (terminated with 0x00)
* @param payload Payload as String
*/
protected void appendPayload(String payload)
{
byte[] payloadarr = payload.getBytes();
int oldpayloadsize = this.payload.length;
byte[] oldpayload = this.payload;
this.payload = new byte[oldpayloadsize+payloadarr.length+1]; // Create new Array with more place (+1 for string terminator)
System.arraycopy(oldpayload, 0, this.payload, 0, oldpayloadsize);
System.arraycopy(payloadarr, 0, this.payload, oldpayloadsize, payloadarr.length);
}
/**
* Appends a single Byte to the payload
* @param payload Payload
*/
protected void appendPayload(byte payload)
{
appendPayload(new byte[] { payload });
}
/**
* Appends a Byte-Array to the payload
* @param payloadarr Payload
*/
protected void appendPayload(byte[] payloadarr)
{
int oldpayloadsize = this.payload.length;
byte[] oldpayload = this.payload;
this.payload = new byte[oldpayloadsize+payloadarr.length];
System.arraycopy(oldpayload, 0, this.payload, 0, oldpayloadsize);
System.arraycopy(payloadarr, 0, this.payload, oldpayloadsize, payloadarr.length);
}
/**
* Appends an integer to the payload
* @param i Payload
*/
protected void appendPayload(int i) {
appendPayload(intToByteArray(i));
}
/**
* Appends a short to the payload
* @param s Payload
*/
protected void appendPayload(short s) {
appendPayload(shortToByteArray(s));
}
/**
* Get Number of Packets which will be sent with current Payload...
* @return Number of Packets
*/
public int getNumPackets()
{
// return (payload.length + (MAX_PAYLOAD_SIZE - 1)) / MAX_PAYLOAD_SIZE;
return 1 + Math.max(payload.length - 1, 0) / MAX_PAYLOAD_SIZE;
}
/**
* Get Header for a specific Packet in this sequence...
* @param seq Current sequence number
* @param maxseq Maximal sequence number
* @param actpayloadsize Payloadsize of this packet
* @return Byte-Array with Header information (currently 32-Byte long, see HEADER_SIZE)
*/
private byte[] getHeader(int seq, int maxseq, short actpayloadsize)
{
byte[] header = new byte[HEADER_SIZE];
System.arraycopy(sig, 0, header, 0, 4);
header[4] = majver;
header[5] = minver;
byte[] packettypearr = shortToByteArray(this.packettype);
System.arraycopy(packettypearr, 0, header, 6, 2);
byte[] seqarr = intToByteArray(seq);
System.arraycopy(seqarr, 0, header, 8, 4);
byte[] maxseqarr = intToByteArray(maxseq);
System.arraycopy(maxseqarr, 0, header, 12, 4);
byte[] payloadsize = shortToByteArray(actpayloadsize);
System.arraycopy(payloadsize, 0, header, 16, 2);
byte[] uid = intToByteArray(Packet.uid);
System.arraycopy(uid, 0, header, 18, 4);
byte[] reserved = new byte[10];
System.arraycopy(reserved, 0, header, 22, 10);
return header;
}
/**
* Generates the whole UDP-Message with Header and Payload of a specific Packet in sequence
* @param seq Current sequence number
* @return Byte-Array with UDP-Message
*/
private byte[] getUDPMessage(int seq)
{
int maxseq = getNumPackets();
if(seq > maxseq)
return null;
short actpayloadsize;
if(seq == maxseq)
actpayloadsize = (short)((payload.length - 1) % MAX_PAYLOAD_SIZE + 1);
else
actpayloadsize = (short)MAX_PAYLOAD_SIZE;
byte[] pack = new byte[HEADER_SIZE+actpayloadsize];
System.arraycopy(getHeader(seq, maxseq, actpayloadsize), 0, pack, 0, HEADER_SIZE);
System.arraycopy(payload, (seq-1)*MAX_PAYLOAD_SIZE, pack, HEADER_SIZE, actpayloadsize);
return pack;
}
/**
* Sends this packet to the EventServer
* @param adr Address of the EventServer
* @param port Port of the EventServer
* @throws IOException
*/
public void send(InetAddress adr, int port) throws IOException
{
int maxseq = getNumPackets();
DatagramSocket s = new DatagramSocket();
// For each Packet in Sequence...
for(int seq=1;seq<=maxseq;seq++)
{
// Get Message and send them...
byte[] pack = getUDPMessage(seq);
DatagramPacket p = new DatagramPacket(pack, pack.length);
p.setAddress(adr);
p.setPort(port);
s.send(p);
}
}
/**
* Helper Method to convert an integer to a Byte array
* @param value
* @return Byte-Array
*/
private static final byte[] intToByteArray(int value) {
return new byte[] {
(byte)(value >>> 24),
(byte)(value >>> 16),
(byte)(value >>> 8),
(byte)value};
}
/**
* Helper Method to convert an short to a Byte array
* @param value
* @return Byte-Array
*/
private static final byte[] shortToByteArray(short value) {
return new byte[] {
(byte)(value >>> 8),
(byte)value};
}
}