Class: Net::DNS::RR::OPT

Inherits:
Net::DNS::RR show all
Defined in:
lib/Net/DNS/RR/OPT.rb

Overview

NAME

Net::DNS::RR::OPT - DNS OPT

DESCRIPTION

Class for EDNS pseudo resource record OPT.

Construction

This object should only be used inside the Net::DNS classes itself.

Since “OPT” is a pseudo record and should not be stored in masterfiles; Therefore we have not implemented a method to create this RR from string.

One may create the object from a hash. See RFC 2671 for details for the meaning of the hash keys.

rr= Net::DNS::RR.new_from_hash( 

'name' => "",     # Ignored and set to ""
'type' => "OPT",  
'class' => 1024,    # sets UDP payload size
:extendedrcode =>  0x00,    # sets the extended RCODE 1 octets
:ednsflags     =>  0x0000,  # sets the ednsflags (2octets)  
:optioncode   =>   0x0      # 2 octets
:optiondata   =>   0x0      # optionlength octets

)

The ednsversion is set to 0 for now. The ttl value is determined from the extendedrcode, the ednsversion and the ednsflag. The rdata is constructed from the optioncode and optiondata see section 4.4 of RFC 2671

If optioncode is left undefined then we do not expect any RDATA.

The defaults are no rdata.

TODO

  • This class is tailored to use with dnssec.

  • Do some range checking on the input.

  • This class probably needs subclasses once OPTION codes start to be defined.

  • look at use of extended labels

COPYRIGHT

Copyright © 2001, 2002 RIPE NCC. Author Olaf M. Kolkman

Ruby version Copyright © 2006 AlexD (Nominet UK)

All Rights Reserved

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of the author not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission.

THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS; IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Based on, and contains, code by Copyright © 1997-2002 Michael Fuhr.

SEE ALSO

Net::DNS, Net::DNS::Resolver, Net::DNS::Packet, Net::DNS::Header, Net::DNS::Question, Net::DNS::RR, RFC 2435 Section 3

Constant Summary collapse

@@EDNSVERSION = 
0
@@extendedrcodesbyname = 
{
  "ONLY_RDATA" => 0,   # No name specified see 4.6 of 2671 
  "UNDEF1"     => 1,
  "UNDEF2"     => 2,
  "UNDEF3"     => 3,
  "UNDEF4"     => 4,
  "UNDEF5"     => 5,
  "UNDEF6"     => 6,
  "UNDEF7"     => 7,
  "UNDEF8"     => 8,
  "UNDEF9"     => 9,
  "UNDEF10"    => 10,
  "UNDEF11"    => 11,
  "UNDEF12"    => 12,
  "UNDEF13"    => 13,
  "UNDEF14"    => 14,
  "UNDEF15"    => 15,
  "BADVERS"    => 16,    # RFC 2671
}
@@extendedrcodesbyval =

RFC 2671

@@extendedrcodesbyname.invert

Constants inherited from Net::DNS::RR

RRS

Instance Attribute Summary collapse

Attributes inherited from Net::DNS::RR

#name, #rdata, #rdlength, #rrclass, #ttl, #type

Instance Method Summary collapse

Methods inherited from Net::DNS::RR

#_canonicalRdata, #_canonicaldata, _get_subclass, _name2wire, #_name2wire, build_regex, create, #create_rrsort_func, #data, #get_rrsort_func, #init, #init_rrsort_func, #inspect, new_from_data, new_from_hash, new_from_string, #set_rrsort_func

Instance Attribute Details

#ednsflags ⇒ Object

Returns the value of attribute ednsflags.



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# File 'lib/Net/DNS/RR/OPT.rb', line 100

def ednsflags
  @ednsflags
end

#ednsversion ⇒ Object

Returns the value of attribute ednsversion.



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# File 'lib/Net/DNS/RR/OPT.rb', line 100

def ednsversion
  @ednsversion
end

#extendedrcode ⇒ Object

Returns the value of attribute extendedrcode.



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# File 'lib/Net/DNS/RR/OPT.rb', line 100

def extendedrcode
  @extendedrcode
end

#optioncode ⇒ Object

Returns the value of attribute optioncode.



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# File 'lib/Net/DNS/RR/OPT.rb', line 100

def optioncode
  @optioncode
end

#optiondata ⇒ Object

Returns the value of attribute optiondata.



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# File 'lib/Net/DNS/RR/OPT.rb', line 100

def optiondata
  @optiondata
end

#optionlength ⇒ Object

Returns the value of attribute optionlength.



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# File 'lib/Net/DNS/RR/OPT.rb', line 100

def optionlength
  @optionlength
end

Instance Method Details

#clear_do_flag ⇒ Object

Clears the do flag. (first bit in the ednssflags);



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# File 'lib/Net/DNS/RR/OPT.rb', line 227

def clear_do_flag
  return @ednsflags = ( ~0x8000 & @ednsflags );
end

#do_flag ⇒ Object

Reads the do flag. (first bit in the ednssflags);



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# File 'lib/Net/DNS/RR/OPT.rb', line 217

def do_flag
  return ( 0x8000 & @ednsflags );
end

#inpsect ⇒ Object 



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# File 'lib/Net/DNS/RR/OPT.rb', line 193

def inpsect
  return "; EDNS Version "     + @ednsversion + \
  "\t UDP Packetsize: " +  @class  +  "\n; EDNS-RCODE:\t"   + @extendedrcode  + \
  " (" + @@extendedrcodesbyval[@extendedrcode] + ")" + \
  "\n; EDNS-FLAGS:\t"   + sprintf("0x%04x", @ednsflags) + "\n";
end

#new_from_data(data, offset) ⇒ Object 



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# File 'lib/Net/DNS/RR/OPT.rb', line 126

def new_from_data(data, offset)
  @name = "" ;   # should allway be "root"
  
  if (@rdlength > 0)
    @optioncode   = data[offset, 2].unpack("n")[0];
    @optionlength = data[offset+2, 2].unpack("n")[0];
    @optiondata   = data[offset+4, @optionlength].unpack("n");
  end
  
  @_rcode_flags  = [ttl].pack("N");
  
  @extendedrcode = @_rcode_flags[0, 1].unpack("C")[0];
  @ednsversion   = @_rcode_flags[1, 1].unpack("C")[0];
  @ednsflags     = @_rcode_flags[2, 2].unpack("n")[0];
end

#new_from_hash(values) ⇒ Object 



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# File 'lib/Net/DNS/RR/OPT.rb', line 154

def new_from_hash(values)
  @name = "" ;   # should allway be "root"
  
  
  # Setting the MTU smaller then 512 does not make sense 
  # should we test for a maximum here?
  if (@rrclass == "IN" || @rrclass.to_s.to_i < 512) 
    @rrclass = 512;    # Default value...
  end
  
  @extendedrcode = 0
  if values.has_key?:extendedrcode
    @extendedrcode = values[:extendedrcode]
  end
  
  @ednsflags   = 0;
  if values.has_key?:ednsflags
    @ednsflags = values[:ednsflags]
  end
  
  @ednsversion = @@EDNSVERSION;
  if values.has_key?:ednsversion
    @ednsversion = values[:ednsversion]
  end
  
  @ttl= ([@extendedrcode].pack("C") + [@ednsversion].pack("C") + [@ednsflags].pack("n")).unpack("N")[0]
  
  if (values.has_key?:optioncode)
    @optiondata   = ""
    if values.has_key(:optiondata)
      @optiondata= values[:optiondata]
    end
    @optionlength = @optiondata.length 
  end
end

#new_from_string(*args) ⇒ Object

Raises:

  • (RuntimeError) 


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# File 'lib/Net/DNS/RR/OPT.rb', line 146

def new_from_string(*args)
  # There is no such thing as an OPT RR in a ZONE file. 
  # Not implemented!
  raise RuntimeError, "You should not try to create a OPT RR from a string\nNot implemented";
end

#rdatastr ⇒ Object 



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# File 'lib/Net/DNS/RR/OPT.rb', line 201

def rdatastr
  return '; Parsing of OPT rdata is not yet implemented';
end

#rr_rdata(*args) ⇒ Object 



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# File 'lib/Net/DNS/RR/OPT.rb', line 205

def rr_rdata(*args)
  rdata="";
  
  if (defined?@optioncode)
    rdata  = pack("n", @optioncode);
    rdata += pack("n", @optionlength); 
    rdata += @optiondata
  end 
  return rdata;
end

#set_do_flag ⇒ Object

Sets the do flag. (first bit in the ednssflags);



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# File 'lib/Net/DNS/RR/OPT.rb', line 222

def set_do_flag
  return @ednsflags = ( 0x8000 | @ednsflags );
end

#size ⇒ Object

Get the packet size.

print "Packet size:". opt.size



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# File 'lib/Net/DNS/RR/OPT.rb', line 245

def size
  return @rrclass
end

#size=(s) ⇒ Object

Set the packet size.

opt.size(1498)



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# File 'lib/Net/DNS/RR/OPT.rb', line 234

def size=(s)
  if (s != nil)
    @rrclass=s;
  end
  return @rrclass;
end