private static short checksum(ChannelBuffer buf) {
short sum = 0;
for (int i = 0; i < buf.readableBytes(); i++) {
sum ^= buf.getUnsignedByte(i);
}
return sum;
}
/**
* Read a PeerAddress from a Netty buffer. I did not want to include ChannelBuffer in the class
* PeerAddress
*
* @param buffer The Netty buffer
* @return A PeerAddress created from the buffer (deserialized)
*/
private static PeerAddress readPeerAddress(final ChannelBuffer buffer) {
if (buffer.readableBytes() < 21) return null;
Number160 id = readID(buffer);
// peek
int type = buffer.getUnsignedByte(buffer.readerIndex());
// now we know the length
int len = PeerAddress.expectedSocketLength(type);
if (buffer.readableBytes() < len) return null;
PeerAddress peerAddress =
new PeerAddress(id, buffer.array(), buffer.arrayOffset() + buffer.readerIndex());
buffer.skipBytes(len);
return peerAddress;
}
/**
* Simple "content sniffing". May not be a great idea, but will do until this class has a better
* API.
*
* @param buf The content of the reply to send.
* @return The MIME type guessed from {@code buf}.
*/
private String guessMimeTypeFromContents(final ChannelBuffer buf) {
if (!buf.readable()) {
logWarn("Sending an empty result?! buf=" + buf);
return "text/plain";
}
final int firstbyte = buf.getUnsignedByte(buf.readerIndex());
switch (firstbyte) {
case '<': // <html or <!DOCTYPE
return HTML_CONTENT_TYPE;
case '{': // JSON object
case '[': // JSON array
return "application/json"; // RFC 4627 section 6 mandates this.
case 0x89: // magic number in PNG files.
return "image/png";
}
return "text/plain"; // Default.
}
@Override
protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf)
throws Exception {
// Check minimum length
if (buf.readableBytes() < 12) {
return null;
}
int length;
switch (buf.getUnsignedByte(buf.readerIndex())) {
case AutoFonProtocolDecoder.MSG_LOGIN:
length = 12;
break;
case AutoFonProtocolDecoder.MSG_LOCATION:
length = 78;
break;
case AutoFonProtocolDecoder.MSG_HISTORY:
length = 257;
break;
case AutoFonProtocolDecoder.MSG_45_LOGIN:
length = 19;
break;
case AutoFonProtocolDecoder.MSG_45_LOCATION:
length = 34;
break;
default:
length = 0;
break;
}
// Check length and return buffer
if (length != 0 && buf.readableBytes() >= length) {
return buf.readBytes(length);
}
return null;
}
@Override
protected Object decode(final ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer)
throws Exception {
if (buffer.readableBytes() < 5) {
return null;
}
int packetLength = 0;
// SSLv3 or TLS - Check ContentType
boolean tls;
switch (buffer.getUnsignedByte(buffer.readerIndex())) {
case 20: // change_cipher_spec
case 21: // alert
case 22: // handshake
case 23: // application_data
tls = true;
break;
default:
// SSLv2 or bad data
tls = false;
}
if (tls) {
// SSLv3 or TLS - Check ProtocolVersion
int majorVersion = buffer.getUnsignedByte(buffer.readerIndex() + 1);
if (majorVersion >= 3 && majorVersion < 10) {
// SSLv3 or TLS
packetLength = (buffer.getShort(buffer.readerIndex() + 3) & 0xFFFF) + 5;
if (packetLength <= 5) {
// Neither SSLv2 or TLSv1 (i.e. SSLv2 or bad data)
tls = false;
}
} else {
// Neither SSLv2 or TLSv1 (i.e. SSLv2 or bad data)
tls = false;
}
}
if (!tls) {
// SSLv2 or bad data - Check the version
boolean sslv2 = true;
int headerLength = (buffer.getUnsignedByte(buffer.readerIndex()) & 0x80) != 0 ? 2 : 3;
int majorVersion = buffer.getUnsignedByte(buffer.readerIndex() + headerLength + 1);
if (majorVersion >= 2 && majorVersion < 10) {
// SSLv2
if (headerLength == 2) {
packetLength = (buffer.getShort(buffer.readerIndex()) & 0x7FFF) + 2;
} else {
packetLength = (buffer.getShort(buffer.readerIndex()) & 0x3FFF) + 3;
}
if (packetLength <= headerLength) {
sslv2 = false;
}
} else {
sslv2 = false;
}
if (!sslv2) {
// Bad data - discard the buffer and raise an exception.
SSLException e =
new SSLException("not an SSL/TLS record: " + ChannelBuffers.hexDump(buffer));
buffer.skipBytes(buffer.readableBytes());
throw e;
}
}
assert packetLength > 0;
if (buffer.readableBytes() < packetLength) {
return null;
}
// We advance the buffer's readerIndex before calling unwrap() because
// unwrap() can trigger FrameDecoder call decode(), this method, recursively.
// The recursive call results in decoding the same packet twice if
// the readerIndex is advanced *after* decode().
//
// Here's an example:
// 1) An SSL packet is received from the wire.
// 2) SslHandler.decode() deciphers the packet and calls the user code.
// 3) The user closes the channel in the same thread.
// 4) The same thread triggers a channelDisconnected() event.
// 5) FrameDecoder.cleanup() is called, and it calls SslHandler.decode().
// 6) SslHandler.decode() will feed the same packet with what was
// deciphered at the step 2 again if the readerIndex was not advanced
// before calling the user code.
final int packetOffset = buffer.readerIndex();
buffer.skipBytes(packetLength);
return unwrap(ctx, channel, buffer, packetOffset, packetLength);
}
@Override
protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg)
throws Exception {
ChannelBuffer buf = (ChannelBuffer) msg;
buf.skipBytes(4); // system code
int type = buf.readUnsignedByte();
long deviceUniqueId = buf.readUnsignedInt();
if (type != MSG_CLIENT_SERIAL) {
buf.readUnsignedShort(); // communication control
}
byte packetNumber = buf.readByte();
// Send reply
sendReply(channel, deviceUniqueId, packetNumber);
// Parse location
if (type == MSG_CLIENT_STATUS) {
Position position = new Position();
position.setProtocol(getProtocolName());
// Device identifier
if (!identify(String.valueOf(deviceUniqueId), channel)) {
return null;
}
position.setDeviceId(getDeviceId());
buf.readUnsignedByte(); // hardware version
buf.readUnsignedByte(); // software version
buf.readUnsignedByte(); // protocol version
// Status
position.set(Event.KEY_STATUS, buf.getUnsignedByte(buf.readerIndex()) & 0x0f);
int operator = (buf.readUnsignedByte() & 0xf0) << 4;
operator += buf.readUnsignedByte();
buf.readUnsignedByte(); // reason data
buf.readUnsignedByte(); // reason
buf.readUnsignedByte(); // mode
buf.readUnsignedInt(); // IO
operator <<= 8;
operator += buf.readUnsignedByte();
position.set("operator", operator);
buf.readUnsignedInt(); // ADC
buf.readUnsignedMedium(); // Odometer
buf.skipBytes(6); // multi-purpose data
buf.readUnsignedShort(); // gps fix
buf.readUnsignedByte(); // location status
buf.readUnsignedByte(); // mode 1
buf.readUnsignedByte(); // mode 2
position.setValid(buf.readUnsignedByte() >= 3); // satellites
// Location data
position.setLongitude(buf.readInt() / Math.PI * 180 / 100000000);
position.setLatitude(buf.readInt() / Math.PI * 180 / 100000000.0);
position.setAltitude(buf.readInt() * 0.01);
position.setSpeed(UnitsConverter.knotsFromMps(buf.readInt() * 0.01));
position.setCourse(buf.readUnsignedShort() / Math.PI * 180.0 / 1000.0);
// Time
Calendar time = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
time.clear();
time.set(Calendar.SECOND, buf.readUnsignedByte());
time.set(Calendar.MINUTE, buf.readUnsignedByte());
time.set(Calendar.HOUR_OF_DAY, buf.readUnsignedByte());
time.set(Calendar.DAY_OF_MONTH, buf.readUnsignedByte());
time.set(Calendar.MONTH, buf.readUnsignedByte() - 1);
time.set(Calendar.YEAR, buf.readUnsignedShort());
position.setTime(time.getTime());
return position;
}
return null;
}
private ParseResult parsePosition(ChannelBuffer buf) {
Position position = new Position();
position.setProtocol(getProtocolName());
position.setDeviceId(getDeviceId());
int format;
if (buf.getUnsignedByte(buf.readerIndex()) == 0) {
format = buf.readUnsignedShort();
} else {
format = buf.readUnsignedByte();
}
position.set("format", format);
long index = buf.readUnsignedInt();
position.set(Event.KEY_INDEX, index);
position.set(Event.KEY_EVENT, buf.readUnsignedShort());
buf.skipBytes(6); // event time
position.set(Event.KEY_ALARM, buf.readUnsignedByte());
position.set(Event.KEY_STATUS, buf.readUnsignedByte());
position.set(Event.KEY_GSM, buf.readUnsignedByte());
if (isFormat(format, F10, F20, F30)) {
position.set(Event.KEY_OUTPUT, buf.readUnsignedShort());
} else if (isFormat(format, F40, F50, F51, F52)) {
position.set(Event.KEY_OUTPUT, buf.readUnsignedByte());
}
if (isFormat(format, F10, F20, F30, F40)) {
position.set(Event.KEY_INPUT, buf.readUnsignedShort());
} else if (isFormat(format, F50, F51, F52)) {
position.set(Event.KEY_INPUT, buf.readUnsignedByte());
}
position.set(Event.KEY_POWER, buf.readUnsignedShort() * 0.001);
position.set(Event.KEY_BATTERY, buf.readUnsignedShort());
if (isFormat(format, F10, F20, F30)) {
position.set(Event.PREFIX_TEMP + 1, buf.readShort());
}
if (isFormat(format, F10, F20, F50, F52)) {
position.set(Event.PREFIX_ADC + 1, buf.readUnsignedShort());
position.set(Event.PREFIX_ADC + 2, buf.readUnsignedShort());
}
// Impulse counters
if (isFormat(format, F20, F50, F51, F52)) {
buf.readUnsignedInt();
buf.readUnsignedInt();
}
if (isFormat(format, F20, F50, F51, F52)) {
int locationStatus = buf.readUnsignedByte();
position.setValid(BitUtil.check(locationStatus, 1));
DateBuilder dateBuilder =
new DateBuilder()
.setTime(buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedByte())
.setDateReverse(
buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedByte());
position.setTime(dateBuilder.getDate());
position.setLatitude(buf.readFloat() / Math.PI * 180);
position.setLongitude(buf.readFloat() / Math.PI * 180);
position.setSpeed(buf.readFloat());
position.setCourse(buf.readUnsignedShort());
position.set(Event.KEY_ODOMETER, buf.readFloat());
position.set("segment", buf.readFloat()); // last segment
// Segment times
buf.readUnsignedShort();
buf.readUnsignedShort();
}
// Other
if (isFormat(format, F51, F52)) {
buf.readUnsignedShort();
buf.readByte();
buf.readUnsignedShort();
buf.readUnsignedShort();
buf.readByte();
buf.readUnsignedShort();
buf.readUnsignedShort();
buf.readByte();
buf.readUnsignedShort();
}
// Four temperature sensors
if (isFormat(format, F40, F52)) {
buf.readByte();
buf.readByte();
buf.readByte();
buf.readByte();
}
return new ParseResult(index, position);
}
@Override
public int getUnsignedByte() {
return buffer.getUnsignedByte(buffer.readerIndex());
}
@Override
protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg)
throws Exception {
ChannelBuffer buf = (ChannelBuffer) msg;
buf.readUnsignedShort(); // device id
buf.readUnsignedByte(); // length
int type = buf.readUnsignedByte();
DeviceSession deviceSession;
if (type == MSG_IMEI) {
deviceSession =
getDeviceSession(
channel, remoteAddress, buf.readBytes(15).toString(StandardCharsets.US_ASCII));
} else {
deviceSession = getDeviceSession(channel, remoteAddress);
}
if (deviceSession == null) {
return null;
}
if (BitUtil.to(type, 2) == 0) {
Position position = new Position();
position.setProtocol(getProtocolName());
position.setDeviceId(deviceSession.getDeviceId());
buf.readUnsignedByte(); // firmware version
buf.readUnsignedShort(); // index
position.set(Position.KEY_STATUS, buf.readUnsignedShort());
position.setValid(true);
position.setLatitude(buf.readFloat());
position.setLongitude(buf.readFloat());
position.setCourse(buf.readUnsignedShort() * 0.1);
position.setSpeed(UnitsConverter.knotsFromKph(buf.readUnsignedShort() * 0.1));
buf.readUnsignedByte(); // acceleration
position.setAltitude(buf.readUnsignedShort());
position.set(Position.KEY_HDOP, buf.readUnsignedByte() * 0.1);
position.set(Position.KEY_SATELLITES, buf.readUnsignedByte() & 0x0f);
position.setTime(new Date(buf.readUnsignedInt() * 1000));
position.set(Position.KEY_POWER, buf.readUnsignedShort());
position.set(Position.KEY_BATTERY, buf.readUnsignedShort());
if (BitUtil.check(type, 2)) {
buf.skipBytes(4);
}
if (BitUtil.check(type, 3)) {
buf.skipBytes(12);
}
if (BitUtil.check(type, 4)) {
buf.skipBytes(8);
}
if (BitUtil.check(type, 5)) {
buf.skipBytes(9);
}
if (BitUtil.check(type, 6)) {
buf.skipBytes(buf.getUnsignedByte(buf.readerIndex()));
}
if (BitUtil.check(type, 7)) {
position.set(Position.KEY_ODOMETER, buf.readUnsignedInt());
}
return position;
}
return null;
}