<?
///////////////////////////////////////////////////////////////////////////
//
//    DNSBL - Spam IP address checker.
//    Copyright (C) 2011 Alexey A.Znayev
//
//    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 3 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, see <http://www.gnu.org/licenses/>.
//
//    Alexey A.Znayev, znaeff@mail.ru, http://xbsoft.org, http://xbsoft.ru
//
///////////////////////////////////////////////////////////////////////////

// This file contains public class DNSBL

// This class performs IP address check in spam blocking lists as described
// on http://ru.wikipedia.org/wiki/RBL

class DNSBL {

    private $_aCheckers = array(	// list of checkers available for individual checking
	    'spamhaus' 	=> array('.zen.spamhaus.org', true), 	//available for group checking with 'all' key
	    'spamcop' 	=> array('.bl.spamcop.net',   true),	//available for group checking with 'all' key
	    'dsbl' 	=> array('.list.dsbl.org',    false),	//not available for group checking with 'all' key
	    'ordb' 	=> array('.relays.ordb.org',  false),	//not available for group checking with 'all' key
	    'sorbs' 	=> array('.dnsbl.sorbs.net',  false),	//not available for group checking with 'all' key
	    'njabl' 	=> array('.dnsbl.njabl.org',  false)	//not available for group checking with 'all' key
    ); // AZ - 1. Key 'all' is illegal
       // AZ - 2. Most of spammer IP addresses is covered by 'spamhaus' & 'spamcop' (and they are fast),
       //         some of the rest may not work sometimes, you can make them group checking available after individual testing
    
    private $_sDefaultChecker = 'spamhaus';

///////////////////////////////////////////////////////////////////////////
// CheckSpamIP - check IP for spam in checkers : given, default or all available for group checking (may be slow)
// parameters:
// string $ip - ip address
// string $checker - checker name or 'all' or nothing
// returns:
// true when IP exitsts in spam-lists of $checker or at least one of all checkers
// false when not or when ip address is local or not correct
    public function CheckSpamIP($ip, $checker = ''){
	if(empty($ip)) return false;
	if(preg_match('/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/', $ip) != 1) return false;
	$octets = explode('.', $ip);
	if($octets[0] == '127') return false;
	if($octets[0] == '10') return false;
	if($octets[0] == '192' && $octets[0] == '168') return false;
	if($octets[0] == '169' && $octets[0] == '254') return false;	// ms windows
	if((int)$octets[0] > 255 || (int)$octets[1] > 255 || (int)$octets[2] > 255 || (int)$octets[3] > 255 ) return false;
	$ret_val = false;
	$PTR = implode(array_reverse($octets), '.');
	if($checker === 'all'){
	    foreach(array_values($this->_aCheckers) as $c){
		if($c[1]){
		    $ret_val = $ret_val || $this->_CheckDNSAnswer(dns_get_record($PTR . $c[0], DNS_A));
		}
		if($ret_val) break;
	    }
	}else if(array_key_exists($checker, $this->_aCheckers)){
    	    $ret_val = $this->_CheckDNSAnswer(dns_get_record($PTR . $this->_aCheckers[$checker][0], DNS_A));
	}else{
    	    $ret_val = $this->_CheckDNSAnswer(dns_get_record($PTR . $this->_aCheckers[$this->_sDefaultChecker][0], DNS_A));
	}
	return $ret_val;
    }

///////////////////////////////////////////////////////////////////////////
// GetCheckers - gets list of available checker names
// returns:
// array of strings
    public function GetCheckers(){
	return array_keys($this->_aCheckers);
    }        

///////////////////////////////////////////////////////////////////////////
// GetGroupCheckers - gets list of checker names available for group checking with 'all' key
// returns:
// array of strings
    public function GetGroupCheckers(){
	$ret_val = array();
	foreach(array_keys($this->_aCheckers) as $k) if($this->_aCheckers[$k][1]) array_push($ret_val, $k);
	return $ret_val;
    }        

///////////////////////////////////////////////////////////////////////////
// GetDefaultChecker - gets default checker name
// returns:
// string
    public function GetDefaultChecker(){
	return $this->_sDefaultChecker;
    }

///////////////////////////////////////////////////////////////////////////
// SetDefaultChecker - sets default checker name
// parameters:
// string $new_checker - new default checker name
// returns:
// true when success
// false when failed ($new_checker is not in the list of available checker names)
    public function SetDefaultChecker($new_checker){
	if(array_key_exists($new_checker, $this->_aCheckers)){
	    $this->_sDefaultChecker = $new_checker;
	    return true;
	}else{
	    return false;
	}
    }

///////////////////////////////////////////////////////////////////////////
// EnableGroupChecking - sets checker available for group checking
// parameters:
// string $checker - checker name
// returns:
// true when success ($checker is included)
// false when failed ($checker is not in the list of available checker names)
    public function EnableGroupChecking($checker){
	if(array_key_exists($checker, $this->_aCheckers)){
	    $this->_aCheckers[$checker][1] = true;
	    return true;
	}else{
	    return false;
	}
    }

///////////////////////////////////////////////////////////////////////////
// DisableGroupChecking - sets checker not available for group checking
// parameters:
// string $checker - checker name
// returns:
// true when success ($checker is excluded)
// false when failed ($checker is not in the list of available checker names)
    public function DisableGroupChecking($checker){
	if(array_key_exists($checker, $this->_aCheckers)){
	    $this->_aCheckers[$checker][1] = false;
	    return true;
	}else{
	    return false;
	}
    }

// private methods

///////////////////////////////////////////////////////////////////////////
// _CheckDNSAnswer - checks DNS-server answer for 127.0.0.* values
// returns:
// true when success
// false when failed
    private function _CheckDNSAnswer($dns_answer){
	if(!is_array($dns_answer)) return false;
	$len = count($dns_answer);
	if($len <= 0) return false;
	for($i=0; $i<$len; $i++){
	    $obj = $dns_answer[$i];
	    if(!(is_object($obj) || is_array($obj))) return false;
	    $ip_str = $obj['ip'];
	    if(!is_string($ip_str)) return false;
	    $pos = strpos($ip_str, '127.0.0.');
	    if($pos !== false) return true;
	}
	return false;
    }        

} // end of class DNSBL

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