/*
* Created on 29-Jun-2004
* Created by Paul Gardner
* Copyright (C) 2004, 2005, 2006 Aelitis, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* AELITIS, SAS au capital de 46,603.30 euros
* 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
*
*/
package org.gudy.azureus2.core3.util;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
/**
* @author parg
*
*/
public class
HostNameToIPResolver
{
static protected AEThread2 resolver_thread;
static protected List request_queue = new ArrayList();
static protected AEMonitor request_queue_mon = new AEMonitor( "HostNameToIPResolver" );
static protected AESemaphore request_semaphore = new AESemaphore("HostNameToIPResolver");
public static boolean
isNonDNSName(
String host )
{
return( AENetworkClassifier.categoriseAddress( host ) != AENetworkClassifier.AT_PUBLIC );
}
public static InetAddress
syncResolve(
String host )
throws UnknownHostException
{
if ( isNonDNSName( host )){
throw( new HostNameToIPResolverException( "non-DNS name '" + host + "'", true ));
}
// handle any raw addresses up front
byte[] bytes = textToNumericFormat( host );
if ( bytes != null ){
return( InetAddress.getByAddress( bytes ));
}
// filter out partially complete raw addresses by applying the basic rule in ftp://ftp.is.co.za/rfc/rfc3696.txt
// at least one dot + not all numeric
char[] chars = host.toCharArray();
boolean resolve = false;
for (int i=0;i<chars.length;i++){
if ( !( chars[i] == '.' || Character.isDigit(chars[i]))){
resolve = true;
break;
}
}
if ( resolve ){
return( InetAddress.getByName( host));
}else{
throw( new UnknownHostException( "Host '" + host + "' doesn't obey minimal validation rules"));
}
}
public static void
addResolverRequest(
String host,
HostNameToIPResolverListener l )
{
byte[] bytes = textToNumericFormat( host );
if ( bytes != null ){
try{
l.hostNameResolutionComplete( InetAddress.getByAddress( host, bytes ));
return;
}catch( UnknownHostException e ){
}
}
try{
request_queue_mon.enter();
request_queue.add( new request( host, l ));
request_semaphore.release();
if ( resolver_thread == null ){
resolver_thread =
new AEThread2("HostNameToIPResolver",true)
{
public void
run()
{
while(true){
try{
request_semaphore.reserve(30000);
request req;
try{
request_queue_mon.enter();
if ( request_queue.isEmpty()){
resolver_thread = null;
break;
}
req = (request)request_queue.remove(0);
}finally{
request_queue_mon.exit();
}
try{
InetAddress addr = syncResolve( req.getHost());
req.getListener().hostNameResolutionComplete( addr );
}catch( Throwable e ){
req.getListener().hostNameResolutionComplete( null );
}
}catch( Throwable e ){
Debug.printStackTrace( e );
}
}
}
};
resolver_thread.start();
}
}finally{
request_queue_mon.exit();
}
}
public static byte[]
hostAddressToBytes(
String host )
{
byte[] res = textToNumericFormat( host );
return( res );
}
final static int INADDRSZ = 4;
static byte[]
textToNumericFormat(
String src )
{
if (src.length() == 0) {
return null;
}
if ( src.indexOf(':') != -1 ){
// v6
try{
return( InetAddress.getByName(src).getAddress());
}catch( Throwable e ){
return( null );
}
}
int octets;
char ch;
byte[] dst = new byte[INADDRSZ];
char[] srcb = src.toCharArray();
boolean saw_digit = false;
octets = 0;
int i = 0;
int cur = 0;
while (i < srcb.length) {
ch = srcb[i++];
if (Character.isDigit(ch)) {
// note that Java byte is signed, so need to convert to int
int sum = (dst[cur] & 0xff)*10
+ (Character.digit(ch, 10) & 0xff);
if (sum > 255)
return null;
dst[cur] = (byte)(sum & 0xff);
if (! saw_digit) {
if (++octets > INADDRSZ)
return null;
saw_digit = true;
}
} else if (ch == '.' && saw_digit) {
if (octets == INADDRSZ)
return null;
cur++;
dst[cur] = 0;
saw_digit = false;
} else
return null;
}
if (octets < INADDRSZ)
return null;
return dst;
}
protected static class
request
{
protected String host;
protected HostNameToIPResolverListener listener;
protected
request(
String _host,
HostNameToIPResolverListener _listener )
{
host = _host;
listener = _listener;
}
protected String
getHost()
{
return( host );
}
protected HostNameToIPResolverListener
getListener()
{
return( listener );
}
}
}