phpdns解析类

php实现的dns解析类，如下：

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 );
  }
 }
?>