resolver.php

来自「视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.」· PHP 代码 · 共 1,337 行 · 第 1/3 页

<?php
/*
 *  License Information:
 *
 *    Net_DNS:  A resolver library for PHP
 *    Copyright (c) 2002-2003 Eric Kilfoil [e-mail]
 *
 *    This library 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 2.1 of the License, or (at your option) any later version.
 *
 *    This library 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 General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public
 *    License along with this library; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


/* Net_DNS_Resolver object definition {{{ */
/**
 * A DNS Resolver library
 *
 * Resolver library.  Builds a DNS query packet, sends  the packet to the
 * server and parses the reponse.
 *
 * @package Net_DNS
 */
class Net_DNS_Resolver
{
    /* class variable definitions {{{ */
    /**
     * An array of all nameservers to query
     *
     * An array of all nameservers to query
     *
     * @var array   $nameservers
     * @access public
     */
    var $nameservers;
    /**
     * The UDP port to use for the query (default = 53)
     *
     * The UDP port to use for the query (default = 53)
     *
     * @var integer $port
     * @access public
     */
    var $port;
    /**
     * The domain in which the resolver client host resides.
     *
     * The domain in which the resolver client host resides.
     *
     * @var string $domain
     * @access public
     */
    var $domain;
    /**
     * The searchlist to apply to unqualified hosts
     *
     * An array of strings containg domains to apply to unqualified hosts
     * passed to the resolver.
     *
     * @var array $searchlist
     * @access public
     */
    var $searchlist;
    /**
     * The number of seconds between retransmission of unaswered queries
     *
     * The number of seconds between retransmission of unaswered queries
     *
     * @var integer $retrans
     * @access public
     */
    var $retrans;
    /**
     * The number of times unanswered requests should be retried
     *
     * The number of times unanswered requests should be retried
     *
     * @var integer $retry
     * @access public
     */
    var $retry;
    /**
     * Whether or not to use TCP (Virtual Circuits) instead of UDP
     *
     * If set to 0, UDP will be used unless TCP is required.  TCP is
     * required for questions or responses greater than 512 bytes.
     *
     * @var boolean $usevc
     * @access public
     */
    var $usevc;
    /**
     * Unknown
     */
    var $stayopen;
    /**
     * Ignore TC (truncated) bit
     *
     * If the server responds with the TC bit set on a response, and $igntc
     * is set to 0, the resolver will automatically retransmit the request
     * using virtual circuits (TCP).
     *
     * @access public
     * @var boolean $igntc
     */
    var $igntc;
    /**
     * Recursion Desired
     *
     * Sets the value of the RD (recursion desired) bit in the header. If
     * the RD bit is set to 0, the server will not perform recursion on the
     * request.
     *
     * @var boolean $recurse
     * @access public
     */
    var $recurse;
    /**
     * Unknown
     */
    var $defnames;
    /**
     * Unknown
     */
    var $dnsrch;
    /**
     * Contains the value of the last error returned by the resolver.
     *
     * Contains the value of the last error returned by the resolver.
     *
     * @var string $errorstring
     * @access public
     */
    var $errorstring;
    /**
     * The origin of the packet.
     *
     * This contains a string containing the IP address of the name server
     * from which the answer was given.
     *
     * @var string $answerfrom
     * @access public
     */
    var $answerfrom;
    /**
     * The size of the answer packet.
     *
     * This contains a integer containing the size of the DNS packet the
     * server responded with.
     *
     * @var string $answersize
     * @access public
     */
    var $answersize;
    /**
     * The number of seconds after which a TCP connetion should timeout
     *
     * @var integer $tcp_timeout
     * @access public
     */
    var $tcp_timeout;
    /**
     * The location of the system resolv.conf file.
     *
     * The location of the system resolv.conf file.
     * 
     * @var string $resolv_conf
     */
    var $resolv_conf = '/etc/resolv.conf';
    /**
     * The name of the user defined resolv.conf
     *
     * The resolver will attempt to look in both the current directory as
     * well as the user's home directory for a user defined resolver
     * configuration file
     *
     * @var string $dotfile
     * @see Net_DNS_Resolver::$confpath
     */
    var $dotfile = '.resolv.conf';
    /**
     * A array of directories to search for the user's resolver config
     *
     * A array of directories to search for the user's resolver config
     *
     * @var string $confpath
     * @see Net_DNS_Resolver::$dotfile
     */
    var $confpath;
    /**
     * debugging flag
     *
     * If set to TRUE (non-zero), debugging code will be displayed as the
     * resolver makes the request.
     *
     * @var boolean $debug;
     * @access public
     */
    var $debug;
    /**
     * use the (currently) experimental PHP socket library
     *
     * If set to TRUE (non-zero), the Resolver will attempt to use the
     * much more effecient PHP sockets extension (if available).
     *
     * @var boolean $useEnhancedSockets;
     * @access public
     */
    var $useEnhancedSockets = 1;
    /**
     * An array of sockets connected to a name servers
     *
     * @var array $sockets
     * @access private
     */
    var $sockets;
    /**
     * axfr tcp socket
     *
     * Used to store a PHP socket resource for a connection to a server
     *
     * @var resource $_axfr_sock;
     * @access private
     */
    var $_axfr_sock;
    /**
     * axfr resource record lsit
     *
     * Used to store a resource record list from a zone transfer
     *
     * @var resource $_axfr_rr;
     * @access private
     */
    var $_axfr_rr;
    /**
     * axfr soa count
     *
     * Used to store the number of soa records received from a zone transfer
     *
     * @var resource $_axfr_soa_count;
     * @access private
     */
    var $_axfr_soa_count;


    /* }}} */
    /* class constructor - Net_DNS_Resolver() {{{ */
    /**
     * Initializes the Resolver Object
     */
    function Net_DNS_Resolver()
    {
        $default = array(
                'nameservers' => array(),
                'port'    => '53',
                'domain'  => '',
                'searchlist'  => array(),
                'retrans' => 5,
                'retry'   => 4,
                'usevc'   => 0,
                'stayopen'  => 0,
                'igntc'   => 0,
                'recurse' => 1,
                'defnames'  => 1,
                'dnsrch'  => 1,
                'debug'   => 0,
                'errorstring' => 'unknown error or no error',
                'answerfrom'    => '',
                'answersize'    => 0,
                'tcp_timeout'   => 120
                );
        foreach ($default as $k => $v) {
            $this->{$k} = $v;
        }
        $this->confpath[0] = getenv('HOME');
        $this->confpath[1] = '.';
        $this->res_init();
    }

    /* }}} */
    /* Net_DNS_Resolver::res_init() {{{ */
    /**
     * Initalizes the resolver library
     *
     * res_init() searches for resolver library configuration files  an
     * initializes the various properties of the resolver object.
     *
     * @see Net_DNS_Resolver::$resolv_conf, Net_DNS_Resolver::$dotfile,
     *      Net_DNS_Resolver::$confpath, Net_DNS_Resolver::$searchlist,
     *      Net_DNS_Resolver::$domain, Net_DNS_Resolver::$nameservers
     * @access public
     */
    function res_init()
    {
        $err = error_reporting(0);
        if (file_exists($this->resolv_conf) && is_readable($this->resolv_conf)) {
            $this->read_config($this->resolv_conf);
        }

        foreach ($this->confpath as $dir) {
            $file = "$dir/" . $this->dotfile;
            if (file_exists($file) && is_readable($file)) {
                $this->read_config($file);
            }
        }

        $this->read_env();

        if (!strlen($this->domain) && strlen($this->searchlist)) {
            $this->default{'domain'} = $this->default{'searchlist'}[0];
        } else if (! strlen($this->searchlist) && strlen($this->domain)) {
            $this->searchlist = array($this->domain);
        }
        error_reporting($err);
    }

    /* }}} */
    /* Net_DNS_Resolver::read_config {{{ */
    /**
     * Reads and parses a resolver configuration file
     *
     * @param string $file The name of the file to open and parse
     */
    function read_config($file)
    {
        if (! ($f = fopen($file, 'r'))) {
            $this->error = "can't open $file";
        }

        while (! feof($f)) {
            $line = chop(fgets($f, 10240));
            $line = ereg_replace('(.*)[;#].*', '\\1', $line);
            if (ereg("^[ \t]*$", $line, $regs)) {
                continue;
            }
            ereg("^[ \t]*([^ \t]+)[ \t]+([^ \t]+)", $line, $regs);
            $option = $regs[1];
            $value = $regs[2];

            switch ($option) {
                case 'domain':
                    $this->domain = $regs[2];
                    break;
                case 'search':
                    $this->searchlist[count($this->searchlist)] = $regs[2];
                    break;
                case 'nameserver':
                    foreach (split(' ', $regs[2]) as $ns)
                        $this->nameservers[count($this->nameservers)] = $ns;
                    break;
            }
        }
        fclose($f);
    }

    /* }}} */
    /* Net_DNS_Resolver::read_env() {{{ */
    /**
     * Examines the environment for resolver config information
     */
    function read_env()
    {
        if (getenv('RES_NAMESERVERS')) {
            $this->nameservers = split(' ', getenv('RES_NAMESERVERS'));
        }

        if (getenv('RES_SEARCHLIST')) {
            $this->searchlist = split(' ', getenv('RES_SEARCHLIST'));
        }

        if (getenv('LOCALDOMAIN')) {
            $this->domain = getenv('LOCALDOMAIN');
        }

        if (getenv('RES_OPTIONS')) {
            $env = split(' ', getenv('RES_OPTIONS'));
            foreach ($env as $opt) {
                list($name, $val) = split(':', $opt);
                if ($val == '') {
                    $val = 1;
                }
                $this->{$name} = $val;
            }
        }
    }

    /* }}} */
    /* Net_DNS_Resolver::string() {{{ */
    /**
     * Builds a string containing the current state of the resolver
     *
     * Builds formatted string containing the state of the resolver library suited
     * for display.
     *
     * @access public
     */
    function string()
    {
        $state = ";; Net_DNS_Resolver state:\n";
        $state .= ';;  domain       = ' . $this->domain . "\n";
        $state .= ';;  searchlist   = ' . implode(' ', $this->searchlist) . "\n";
        $state .= ';;  nameservers  = ' . implode(' ', $this->nameservers) . "\n";
        $state .= ';;  port         = ' . $this->port . "\n";
        $state .= ';;  tcp_timeout  = ';
        $state .= ($this->tcp_timeout ? $this->tcp_timeout : 'indefinite') . "\n";
        $state .= ';;  retrans  = ' . $this->retrans . '  ';
        $state .= 'retry    = ' . $this->retry . "\n";
        $state .= ';;  usevc    = ' . $this->usevc . '  ';
        $state .= 'stayopen = ' . $this->stayopen . '    ';
        $state .= 'igntc = ' . $this->igntc . "\n";
        $state .= ';;  defnames = ' . $this->defnames . '  ';
        $state .= 'dnsrch   = ' . $this->dnsrch . "\n";
        $state .= ';;  recurse  = ' . $this->recurse . '  ';
        $state .= 'debug    = ' . $this->debug . "\n";
        return($state);
    }

    /* }}} */
    /* Net_DNS_Resolver::nextid() {{{ */
    /**
     * Returns the next request Id to be used for the DNS packet header
     */
    function nextid()
    {
        global $_Net_DNS_packet_id;

        return($_Net_DNS_packet_id++);
    }
    /* }}} */
    /* not completed - Net_DNS_Resolver::nameservers() {{{ */
    /**
     * Unknown - not ported yet
     */
    function nameservers($nsa)
    {
        $defres = new Net_DNS_Resolver();