/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.activemq.transport.protocol;
import java.nio.ByteBuffer;
/**
*
*
*/
public class MqttProtocolVerifier implements ProtocolVerifier {
@Override
public boolean isProtocol(byte[] value) {
ByteBuffer buf = ByteBuffer.wrap(value);
if (!(buf.get() == 16 && validateRemainingLength(buf) && buf.get() == (byte) 0)) {
return false;
}
byte b = buf.get() ;
return ((b == 4 || b == 6) && (buf.get() == 77));
}
private boolean validateRemainingLength(ByteBuffer buffer) {
byte msb = (byte) 0b10000000;
for (byte i = 0; i < 4; i++) {
if ((buffer.get() & msb) != msb) {
return true;
}
}
return false;
}
}