/**
* 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.tcp;
import java.net.Socket;
import java.net.SocketException;
import java.util.HashMap;
import java.util.Map;
/**
* Utilities for determining the values for the bits in the headers of the
* outgoing TCP/IP packets that indicate Traffic Class for use in Quality of
* Service forwarding policies.
*/
public class QualityOfServiceUtils {
private static final int MAX_DIFF_SERV = 63;
private static final int MIN_DIFF_SERV = 0;
private static final Map<String, Integer> DIFF_SERV_NAMES
= new HashMap<String, Integer>();
/** Common names used for Differentiated Services values. */
static {
DIFF_SERV_NAMES.put("CS0", 0);
DIFF_SERV_NAMES.put("CS1", 8);
DIFF_SERV_NAMES.put("CS2", 16);
DIFF_SERV_NAMES.put("CS3", 24);
DIFF_SERV_NAMES.put("CS4", 32);
DIFF_SERV_NAMES.put("CS5", 40);
DIFF_SERV_NAMES.put("CS6", 48);
DIFF_SERV_NAMES.put("CS7", 56);
DIFF_SERV_NAMES.put("AF11", 10);
DIFF_SERV_NAMES.put("AF12", 12);
DIFF_SERV_NAMES.put("AF13", 14);
DIFF_SERV_NAMES.put("AF21", 18);
DIFF_SERV_NAMES.put("AF22", 20);
DIFF_SERV_NAMES.put("AF23", 22);
DIFF_SERV_NAMES.put("AF31", 26);
DIFF_SERV_NAMES.put("AF32", 28);
DIFF_SERV_NAMES.put("AF33", 30);
DIFF_SERV_NAMES.put("AF41", 34);
DIFF_SERV_NAMES.put("AF42", 36);
DIFF_SERV_NAMES.put("AF43", 38);
DIFF_SERV_NAMES.put("EF", 46);
}
private static final int MAX_TOS = 255;
private static final int MIN_TOS = 0;
/**
* @param value A potential value to be used for Differentiated Services.
* @return The corresponding Differentiated Services Code Point (DSCP).
* @throws IllegalArgumentException if the value does not correspond to a
* Differentiated Services Code Point or setting the DSCP is not
* supported.
*/
public static int getDSCP(String value) throws IllegalArgumentException {
int intValue = -1;
// Check the names first.
if (DIFF_SERV_NAMES.containsKey(value)) {
intValue = DIFF_SERV_NAMES.get(value);
} else {
try {
intValue = Integer.parseInt(value);
if (intValue > MAX_DIFF_SERV || intValue < MIN_DIFF_SERV) {
throw new IllegalArgumentException("Differentiated Services"
+ " value: " + intValue + " not in legal range ["
+ MIN_DIFF_SERV + ", " + MAX_DIFF_SERV + "].");
}
} catch (NumberFormatException e) {
// value must have been a malformed name.
throw new IllegalArgumentException("No such Differentiated "
+ "Services name: " + value);
}
}
return adjustDSCPForECN(intValue);
}
/**
* @param value A potential value to be used for Type of Service.
* @return A valid value that can be used to set the Type of Service in the
* packet headers.
* @throws IllegalArgumentException if the value is not a legal Type of
* Service value.
*/
public static int getToS(int value) throws IllegalArgumentException {
if (value > MAX_TOS || value < MIN_TOS) {
throw new IllegalArgumentException("Type of Service value: "
+ value + " not in legal range [" + MIN_TOS + ", " + MAX_TOS
+ ".");
}
return value;
}
/**
* The Differentiated Services values use only 6 of the 8 bits in the field
* in the TCP/IP packet header. Make sure any values the system has set for
* the other two bits (the ECN bits) are maintained.
*
* @param dscp The Differentiated Services Code Point.
* @return A Differentiated Services Code Point that respects the ECN bits
* set on the system.
* @throws IllegalArgumentException if setting Differentiated Services is
* not supported.
*/
private static int adjustDSCPForECN(int dscp)
throws IllegalArgumentException {
// The only way to see if there are any values set for the ECN is to
// read the traffic class automatically set by the system and isolate
// the ECN bits.
Socket socket = new Socket();
try {
int systemTrafficClass = socket.getTrafficClass();
// The 1st and 2nd bits of the system traffic class are the ECN
// bits.
return (dscp << 2) | (systemTrafficClass & 3);
} catch (SocketException e) {
throw new IllegalArgumentException("Setting Differentiated Services"
+ " not supported: " + e);
}
}
}