001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.security.authorize;
020
021import java.net.InetSocketAddress;
022import java.util.Collection;
023import java.util.HashSet;
024
025import org.apache.hadoop.conf.Configuration;
026
027public class ProxyServers {
028  public static final String CONF_HADOOP_PROXYSERVERS = "hadoop.proxyservers";
029  private static volatile Collection<String> proxyServers;
030
031  public static void refresh() {
032    refresh(new Configuration());
033  }
034
035  public static void refresh(Configuration conf){
036    Collection<String> tempServers = new HashSet<String>();
037    // trusted proxy servers such as http proxies
038    for (String host : conf.getTrimmedStrings(CONF_HADOOP_PROXYSERVERS)) {
039      InetSocketAddress addr = new InetSocketAddress(host, 0);
040      if (!addr.isUnresolved()) {
041        tempServers.add(addr.getAddress().getHostAddress());
042      }
043    }
044    proxyServers = tempServers;
045  }
046
047  public static boolean isProxyServer(String remoteAddr) { 
048    if (proxyServers == null) {
049      refresh(); 
050    }
051    return proxyServers.contains(remoteAddr);
052  }
053}