/**
* Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
* contributors
*
* This file is part of EvoSuite.
*
* EvoSuite is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3.0 of the License, or
* (at your option) any later version.
*
* EvoSuite 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
* Lesser Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
*/
package org.evosuite.runtime.vnet;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Used to resolve host names
*
* @author arcuri
*
*/
public class DNS {
/**
* The actual IP address does not really matter, as long
* as it is in the valid format
*/
private static final String MASK = "200.42.42.";
/**
* Used to create unique new mappings
*/
private final AtomicInteger counter;
/**
* Key -> a host name to resolve
* <p>
* Value -> the IP address for the given host
*/
private final Map<String,String> resolved;
public DNS(){
counter = new AtomicInteger(0);
resolved = new ConcurrentHashMap<>();
}
/**
* Get the IP address for the given host name (eg www.evosuite.org)
*
* @param host
* @return {@code null} if the host was not resolved
*/
public synchronized String resolve(String host){
//check if already resolved
String addr = resolved.get(host);
if(addr != null){
return addr;
}
//check if IP numeric
if(EvoIPAddressUtil.textToNumericFormatV4(host) != null){
return host;
}
if(counter.get() > 255){
/*
* In theory, we could mock as many address resolutions
* as we want. But, if addresses are resolved in a loop
* based on an external string, we might end up in
* troubles. so just simulate a failure
*/
return null;
}
//need to create a new mapping
addr = MASK + counter.getAndIncrement();
resolved.put(host, addr);
return addr;
}
}