php dns parsing class

Share a PHP class for operating dns, which can be used for dns query, dns resolution and other operations. Friends in need can refer to it.

Dns resolution class implemented by php, as follows:

<?php
/* -----------

   PHPresolver - PHP DNS resolver library
                 Version 1.1
   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 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

  ----------------------------------------------
*/

 define( "DNS_RECORDTYPE_A", 1 );
 define( "DNS_RECORDTYPE_NS", 2 );
 define( "DNS_RECORDTYPE_CNAME", 5 );
 define( "DNS_RECORDTYPE_SOA", 6 );
 define( "DNS_RECORDTYPE_PTR", 12 );
 define( "DNS_RECORDTYPE_MX", 15 );

 define( "DNS_RECORDTYPE_AAAA", 28 );

 define( "DNS_RECORDTYPE_ANY", 255 );
 
 define( "DNS_RECORDTYPE_TXT", 16 );

/*
 list of record types not yet implemented

 define( "DNS_RECORDTYPE_A6", 38 );
 define( "DNS_RECORDTYPE_NULL", 10 );
 define( "DNS_RECORDTYPE_OPT", 41 );
 define( "DNS_RECORDTYPE_TKEY", 249 );
 define( "DNS_RECORDTYPE_TSIG", 250 );
 define( "DNS_RECORDTYPE_IXFR", 251 );
 define( "DNS_RECORDTYPE_AXFR", 252 );
 define( "DNS_RECORDTYPE_MAILB", 253 );
 define( "DNS_RECORDTYPE_MAILA", 254 );
 define( "DNS_RECORDTYPE_MD", 3 );
 define( "DNS_RECORDTYPE_MF", 4 );
 define( "DNS_RECORDTYPE_MB", 7 );
 define( "DNS_RECORDTYPE_MG", 8 );
 define( "DNS_RECORDTYPE_MR", 9 );
 define( "DNS_RECORDTYPE_WKS", 11 );
 define( "DNS_RECORDTYPE_HINFO", 13 );
 define( "DNS_RECORDTYPE_MINFO", 14 );
 define( "DNS_RECORDTYPE_RP", 17 );
 define( "DNS_RECORDTYPE_AFSDB", 18 );
 define( "DNS_RECORDTYPE_X25", 19 );
 define( "DNS_RECORDTYPE_ISDN", 20 );
 define( "DNS_RECORDTYPE_RT", 21 );
 define( "DNS_RECORDTYPE_NSAP", 22 );
 define( "DNS_RECORDTYPE_NSAP_PTR", 23 );
 define( "DNS_RECORDTYPE_SIG", 24 );
 define( "DNS_RECORDTYPE_KEY", 25 );
 define( "DNS_RECORDTYPE_PX", 26 );
 define( "DNS_RECORDTYPE_GPOS", 27 );
 define( "DNS_RECORDTYPE_LOC", 29 );
 define( "DNS_RECORDTYPE_NXT", 30 );
 define( "DNS_RECORDTYPE_EID", 31 );
 define( "DNS_RECORDTYPE_NIMLOC", 32 );
 define( "DNS_RECORDTYPE_SRV", 33 );
 define( "DNS_RECORDTYPE_ATMA", 34 );
 define( "DNS_RECORDTYPE_NAPTR", 35 );
 define( "DNS_RECORDTYPE_KX", 36 );
 define( "DNS_RECORDTYPE_CERT", 37 );
*/

 define( "DNS_OPCODE_QUERY" , 0x0000 );
 define( "DNS_OPCODE_IQUERY", 0x0800 );
 define( "DNS_OPCODE_STATUS", 0x1000 );
 define( "DNS_OPCODE_NOTIFY", 0x1800 );
 define( "DNS_OPCODE_UPDATE", 0x2000 );

 define( "DNS_RCODE_SUCCESSFUL"   , 0x0001 );
 define( "DNS_RCODE_MALFORMATED"  , 0x0002 );
 define( "DNS_RCODE_FAILEDSERVER" , 0x0003 );
 define( "DNS_RCODE_NAMEERROR"    , 0x0004 );
 define( "DNS_RCODE_UNIMPLEMENTED", 0x0005 );
 define( "DNS_RCODE_REFUSED"      , 0x0006 );

 define( "DNS_HEADERSPEC_IS_RESPONSE"         , 0x8000 );
 define( "DNS_HEADERSPEC_OPCODE_MASK"         , 0x7800 );
 define( "DNS_HEADERSPEC_AUTHORITIVE_ANSWER"  , 0x0400 );
 define( "DNS_HEADERSPEC_TRUNCATED"           , 0x0200 );
 define( "DNS_HEADERSPEC_RECURSION_DESIRED"   , 0x0100 );
 define( "DNS_HEADERSPEC_RECURSION_AVAILABLE" , 0x0080 );
 define( "DNS_HEADERSPEC_RESPONSE_SPEC_MASK"  , 0x0480 );
 define( "DNS_HEADERSPEC_QUERY_SPEC_MASK"     , 0x0300 );
 define( "DNS_HEADERSPEC_RESERVED"            , 0x0e00 );
 define( "DNS_HEADERSPEC_RESULT_CODE_MASK"    , 0x000f );

 define( "DNS_CLASS_INTERNET"                 , 0x0001 );

 define( "DNS_UDP_PACKET_MAX_LENGTH", 512 );

 class DNSRecord
 {
  var $type;
  var $name;
  var $dclass;
  var $ttl;
  var $specific_fields;

  function DNSRecord(
    $name,
    $type,
    $dclass = DNS_CLASS_INTERNET,
    $ttl = 0,
    $specific_fields = false ) {
   $this->name = $name;
   $this->type = $type;
   $this->dclass = $dclass;
   $this->ttl = $ttl;
   $this->specific_fields = $specific_fields;
  }
  function &getTypeSpecificField( $name ) {
   if( $this->specific_fields ) {
    return $this->specific_fields[$name];
   }
   return false;
  }
 }
 class DNSResolver
 {
  var $port;
  var $nameserver;
  var $timeout;
  function DNSResolver( $nameserver, $port = 53, $timeout = 1000000 ) {
   $this->port = $port;
   $this->nameserver = $nameserver;
   $this->timeout = $timeout;
  }
  function sendQuery( $dnsquery, $useTCP = false ) {
   $answer = false;
   $out_buf = $dnsquery->asOctets( false );
   $out_buf_len = strlen( $out_buf );
   if( $out_buf ) {
    if( $useTCP == false && $out_buf_len <= DNS_UDP_PACKET_MAX_LENGTH ) {
     /* connection by UDP */
     if( ( $sock = fsockopen( 'udp://'.$this->nameserver, $this->port, $this->timeout ) ) === false ) {
      return false;
     }
     socket_set_blocking( $sock, true );
     if( fwrite( $sock, $out_buf ) == $out_buf_len ) {
      $answer = new DNSAnswer( $sock, DNS_UDP_PACKET_MAX_LENGTH );
     }
     fclose( $sock );
    } else {
     /* connection by TCP */
     if( ( $sock = fsockopen( $this->nameserver, $this->port, $this->timeout ) ) === false ) {
      return false;
     }
     socket_set_blocking( $sock, true );
     if( fwrite( $sock, pack( 'n', $out_buf_len ) ) == 2 &&
         fwrite( $sock, $out_buf ) == $out_buf_len ) {
      $tmp = unpack( 'nl', fread( $sock, 2 ) );
      $limit_length = $tmp['l'];
      print $limit_length;
      $answer = new DNSAnswer( $sock, $limit_length );
     }
     fclose( $sock );
    }
   }
   return $answer;
  }
 }

 class DNSQuery 
 {
  var $id; // 1 - 65535
  var $header_opcode;
  var $query_record;
  var $flags;

  function DNSQuery( &$dnsrecord, $flags = DNS_HEADERSPEC_RECURSION_DESIRED )
  {
   $this->id = rand( 1, 255 ) | ( rand( 0, 255 ) << 8 );
   $this->flags = $flags & DNS_HEADERSPEC_QUERY_SPEC_MASK;
   $this->header_opcode = DNS_OPCODE_QUERY;
   $this->query_record = &$dnsrecord;
  }
  function asOctets() {
   if( $this->query_record->name === false ) { return false; }
   $buf = '';
   $buf .= pack( "nnnnnn", $this->id, DNS_OPCODE_QUERY | $this->flags, 1, 0, 0, 0 );
   $buf .= $this->query_record->name->asOctets();
   $buf .= pack( "nn", $this->query_record->type, $this->query_record->dclass );
   return $buf;
  }
 }

 class DNSMessageParser
 {
  var $stream;
  var $nbytes_read;
  var $octets;
  var $limit;

  function DNSMessageParser( $stream, $limit ) {
   $this->stream = $stream;
   $this->nbytes_read = 0;
   $this->octets = '';
   $this->limit = $limit;
  }
  function readStreamDirectly( $nbytes ) {
   if( ( $this->limit -= $nbytes ) < 0 ) {
    return false;
   }
   $buf = fread( $this->stream, $nbytes );
   $this->octets .= $buf;
   $this->nbytes_read += $nbytes;
   return $buf;
  }

  function readBufferedStream( $nbytes, $offset ) {
   if( $offset < $this->nbytes_read ) {
    $diff = $this->nbytes_read - $offset;
    if( $nbytes <= $diff ) {
     return substr( $this->octets, $offset, $nbytes );
    } else {
     $buf = substr( $this->octets, $offset, $diff );
     $nbytes -= $diff;
    }
   } else {
    $buf = '';
    while( $offset > $this->nbytes_read ) {
     if( $this->readStreamDirectly( $offset - $this->nbytes_read ) === false ) {
      return false;
     }
    }
   }
   if( ( $_buf = $this->readStreamDirectly( $nbytes ) ) === false ) {
    return false;
   }
   $buf .= $_buf;
   return $buf;
  }
  function getHeaderInfo() {
   if( ( $buf = $this->readStreamDirectly( 12 ) ) === false ) {
    $this = false;
    return;
   }
   return unpack( "nid/nspec/nqdcount/nancount/nnscount/narcount", $buf );
  }
  function getQueryRecords( $nrecs ) {
   $recs = array();
   while( --$nrecs >= 0 ) {
    if( ( $labels = $this->getLabels() ) === false ) {
     $this = false;
     return;
    }
    if( ( $buf = $this->readStreamDirectly( 4 ) ) === false ) {
     $this = false;
     return;
    }
    $info = unpack( "ntype/ndclass", $buf );

    $recs[] = new DNSRecord(
     new DNSName( $labels ),
     $info['type'],
     $info['dclass']
    );
   }
   return $recs;
  }
  function getResourceRecords( $nrecs ) {
   $recs = array();
   while( --$nrecs >= 0 ) {
    if( ( $labels = $this->getLabels() ) === false ) {
     return false;
    }
    if( ( $buf = $this->readStreamDirectly( 10 ) ) === false ) {
     return false;
    }
    $info = unpack( "ntype/ndclass/Nttl/nrdlength", $buf );
    switch( $info['type'] ) {
     case DNS_RECORDTYPE_CNAME:
     case DNS_RECORDTYPE_NS:
     case DNS_RECORDTYPE_PTR:
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields = array( 'dname' => new DNSName( $_labels ) );
      break;

     case DNS_RECORDTYPE_TXT:
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields = array( 'text' => $_labels );
      break;

     case DNS_RECORDTYPE_MX:
      if( ( $buf = $this->readStreamDirectly(2) ) === false ) {
       return false;
      }
      $specific_fields = unpack( 'npreference', $buf );
      if( ( $_labels = $this->getLabels($info['rdlength']-2) ) === false ) {
       return false;
      }
      $specific_fields['exchange'] = new DNSName( $_labels );
      break;

     case DNS_RECORDTYPE_A:
      if( ( $buf = $this->readStreamDirectly(4) ) === false ) {
       return false;
      }
      $specific_fields = array( 'address' => DNSName::newFromString( implode( '.', unpack( 'Ca/Cb/Cc/Cd', $buf ) ) ) );
      break;

     case DNS_RECORDTYPE_AAAA:
      if( ( $buf = $this->readStreamDirectly(16) ) === false ) {
       return false;
      }
      $specific_fields = array( 'address' => DNSName::newFromString( implode( '.', unpack( 
      'Ca/Cb/Cc/Cd/Ce/Cf/Cg/Ch/Ci/Cj/Ck/Cl/Cm/Cn/Co/Cp', $buf ) ).'.IP6.ARPA' ) );
      break;

     case DNS_RECORDTYPE_SOA:
      $specific_fields = array();
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields['source'] = new DNSName( $_labels );
      if( ($_labels = $this->getLabels($info['rdlength']) ) === false ) {
       return false;
      }
      $specific_fields['resp_person'] = array_shift( $_labels ).'@';
      $specific_fields['resp_person'] .= implode( '.', $_labels );

      if( ( $buf = $this->readStreamDirectly(20) ) === false ) {
       return false;
      }
      $specific_fields = array_merge(
       $specific_fields,
       unpack( 'Nserial/Nrefresh/Nretry/Nexpire/Nminttl', $buf )
      );
      break;

     default:
      if( $this->readStreamDirectly( $info['rdlength'] ) === false ) {
       return false;
      }
      $specific_fields = false;
    }

    $recs[] = new DNSRecord(
     new DNSName( $labels ),
     $info['type'],
     $info['dclass'],
     $info['ttl'],
     $specific_fields
    );
   }
   return $recs;
  }
  function getLabels( $max_length = 255, $offset = -1 ) {
   if( $offset < 0 ) { $offset = $this->nbytes_read; }
   $labels = array();
   for(;;) {
    if( --$max_length < 0 ) { return false; }
    if( ( $buf = $this->readBufferedStream( 1, $offset ) ) === false ) {
     return false;
    }
    $label_len = ord( $buf );
    ++$offset;
    if( $label_len < 64 ) {
     /* uncompressed */
     if( ( $max_length -= $label_len ) < 0 ) { return false; }
     if( ( $labels[] = $this->readBufferedStream( $label_len, $offset ) ) === false ) {
      return false;
     }
     $offset += $label_len;
     if( $label_len == 0 ) { break; }
    } else {
     /* compressed */
     if( ( $buf = $this->readBufferedStream( 1, $offset ) ) === false ) {
      return false;
     }
     if( --$max_length < 0 ) {
      return false;
     }
     $_offset = ( ( $label_len & 0x3f ) << 8 ) + ord( $buf );

     if( ($_labels = $this->getLabels( $offset - $_offset, $_offset )) === false ) {
      return false;
     }
     $labels = array_merge( $labels, $_labels );
     break;
    }
   }
   return $labels;
  }
 }

 class DNSAnswer
 {
  var $id;
  var $result_code;
  var $flags;
  var $rec_query;
  var $rec_answer;
  var $rec_authority;
  var $rec_additional;

  function DNSAnswer( &$stream, $limit ) {
   $msgparser = new DNSMessageParser( $stream, $limit );

   $info = & $msgparser->getHeaderInfo();

   $this->id = $info['id'];
   $this->result_code = $info['spec'] & DNS_HEADERSPEC_RESULT_CODE_MASK;
   $this->flags = $info['spec'] & DNS_HEADERSPEC_RESPONSE_SPEC_MASK;

   $nrec_query = $info['qdcount'];
   $nrec_answer = $info['ancount'];
   $nrec_authority = $info['nscount'];
   $nrec_additional = $info['arcount'];
   if( ( $this->rec_query = &$msgparser->getQueryRecords( $nrec_query ) ) === false ) {
    $this = false;
    return;
   }

   if( ( $this->rec_answer = &$msgparser->getResourceRecords( $nrec_answer ) ) === false ) {
    $this = false;
    return;
   }
   if( ( $this->rec_authority = &$msgparser->getResourceRecords( $nrec_authority ) ) === false ) {
    $this = false;
    return;
   }

   if( ( $this->rec_additional = &$msgparser->getResourceRecords( $nrec_additional ) ) === false ) {
    $this = false;
    return;
   }
  }
 }
 class DNSName
 {
  var $labels;

  function DNSName( $labels ) {
   $this->labels = & $labels;
  }
  function isRealDomainName() {
   $i = count( $this->labels ) - 1;
   if( $i >= 1 && strtoupper($this->labels[$i-1]) == 'ARPA' ) {
    return false;
   }
   return true;
  }
  function newFromString( $domain_name ) {
   if( strpos( $domain_name, ':' ) !== false && !ereg( '[^0-9a-fA-f:.]', $domain_name ) ) {
    /* IPv6 address literal expression spec */
    $labels = array();
    $components = explode( ':', $domain_name );
    $ncomponents = count($components);
    $offset = $ncomponents;
    while( --$offset >= 0 ) {
     $subcomps = explode( '.', $components[$offset] );
     $nsubcomps = count( $subcomps );
     if( $nsubcomps == 1 ) {
      if( $subcomps[0] == '' ) {
       $_offset = 0;
       while( $components[$_offset] != '' ) {
        ++$_offset;
       }
       $count = 9-($ncomponents-$offset)+$_offset;
       while( --$count >= 0 ) {
        $labels[] = '0';
        $labels[] = '0';
        $labels[] = '0';
        $labels[] = '0';
       }
       if( $_offset < $offset ) {
        $offset = $_offset;
       }
      } else {
       $compval = hexdec( $subcomps[0] );
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
       $labels[] = dechex( $compval & 0x0f );
       $compval >>= 4;
      }
     } elseif( $nsubcomps == 4 ) {
      $labels[] = dechex( $subcomps[3] );
      $labels[] = dechex( $subcomps[2] );
      $labels[] = dechex( $subcomps[1] );
      $labels[] = dechex( $subcomps[0] );
     } else {
      return false;
     }
    }
    $labels[] = 'IP6';
    $labels[] = 'ARPA';
    $labels[] = '';
   } else {
    if( substr( $domain_name, -1, 1 ) != '.' ) {
     $domain_name .= '.';
    }
    $labels = explode( '.', $domain_name );
    $nlabels = count( $labels );
    if( $nlabels == 5 && !ereg( '[^0-9.]', $domain_name ) ) {
     /* IPv4 raw address literal representation spec */
     $tmp = (string)$labels[0];
     $labels[0] = (string)$labels[3];
     $labels[3] = $tmp;
     $tmp = (string)$labels[1];
     $labels[1] = (string)$labels[2];
     $labels[2] = $tmp;
     $labels[4] = 'IN-ADDR';
     $labels[5] = 'ARPA';
     $labels[6] = '';
    }
   }
   return new DNSName( $labels );
  }
  function asOctets() {
   $upto = count( $this->labels );
   $buf = '';
   for( $offset = 0; $offset < $upto; ++$offset ) {
    $label_len = strlen( $this->labels[$offset] );
    $buf .= pack( "C", $label_len ).$this->labels[$offset];
   }
   return $buf;
  }
  function getCanonicalName() {
   return implode( ".", $this->labels );
  }
 }
?>