Class Net::DNS::RR
In: lib/net/dns/rr.rb
lib/net/dns/rr/a.rb
lib/net/dns/rr/txt.rb
lib/net/dns/rr/soa.rb
lib/net/dns/rr/mr.rb
lib/net/dns/rr/srv.rb
lib/net/dns/rr/hinfo.rb
lib/net/dns/rr/aaaa.rb
lib/net/dns/rr/ns.rb
lib/net/dns/rr/null.rb
lib/net/dns/rr/classes.rb
lib/net/dns/rr/mx.rb
lib/net/dns/rr/ptr.rb
lib/net/dns/rr/cname.rb
lib/net/dns/rr/types.rb
Parent: Object

Net::DNS::RR - DNS Resource Record class

The Net::DNS::RR is the base class for DNS Resource Record (RR) objects. A RR is a pack of data that represents resources for a DNS zone. The form in which this data is shows can be drawed as follow:

  "name  ttl  class  type  data"

The name is the name of the resource, like an canonical name for an A record (internet ip address). The ttl is the time to live, expressed in seconds. type and class are respectively the type of resource (A for ip addresses, NS for nameservers, and so on) and the class, which is almost always IN, the Internet class. At the end, data is the value associated to the name for that particular type of resource record. An example:

  # A record for IP address
  "www.example.com  86400  IN  A  172.16.100.1"

  # NS record for name server
  "www.example.com  86400  IN  NS  ns.example.com"

A new RR object can be created in 2 ways: passing a string such the ones above, or specifying each field as the pair of an hash. See the Net::DNS::RR.new method for details.

Methods

cls   comp_data   data   inspect   name   new   parse   parse_packet   rdata   to_a   to_s   ttl   type   value  

Included Modules

Names

Classes and Modules

Class Net::DNS::RR::A
Class Net::DNS::RR::AAAA
Class Net::DNS::RR::CNAME
Class Net::DNS::RR::Classes
Class Net::DNS::RR::DataError
Class Net::DNS::RR::Error
Class Net::DNS::RR::HINFO
Class Net::DNS::RR::MR
Class Net::DNS::RR::MX
Class Net::DNS::RR::NS
Class Net::DNS::RR::NULL
Class Net::DNS::RR::PTR
Class Net::DNS::RR::SOA
Class Net::DNS::RR::SRV
Class Net::DNS::RR::TXT
Class Net::DNS::RR::Types

Constants

RR_REGEXP = Regexp.new("^\\s*(\\S+)\\s*(\\d+)?\\s+(" + Net::DNS::RR::Classes.regexp + "|CLASS\\d+)?\\s*(" + Net::DNS::RR::Types.regexp + "|TYPE\\d+)?\\s*(.*)$", Regexp::IGNORECASE)   Regexp matching an RR string
RRFIXEDSZ = 10   Dimension of the sum of class, type, TTL and rdlength fields in a RR portion of the packet, in bytes

Public Class methods

Create a new instance of Net::DNS::RR class, or an instance of any of the subclass of the appropriate type.

Argument can be a string or an hash. With a sting, we can pass a RR resource record in the canonical format:

  a     = Net::DNS::RR.new("foo.example.com. 86400 A 10.1.2.3")
  mx    = Net::DNS::RR.new("example.com. 7200 MX 10 mailhost.example.com.")
  cname = Net::DNS::RR.new("www.example.com 300 IN CNAME www1.example.com")
  txt   = Net::DNS::RR.new('baz.example.com 3600 HS TXT "text record"')

Incidentally, a, mx, cname and txt objects will be instances of respectively Net::DNS::RR::A, Net::DNS::RR::MX, Net::DNS::RR::CNAME and Net::DNS::RR::TXT classes.

The name and RR data are required; all other informations are optional. If omitted, the TTL defaults to 10800, type default to A and the RR class defaults to IN. Omitting the optional fields is useful for creating the empty RDATA sections required for certain dynamic update operations. All names must be fully qualified. The trailing dot (.) is optional.

The preferred method is however passing an hash with keys and values:

  rr = Net::DNS::RR.new(
                :name    => "foo.example.com",
                :ttl     => 86400,
                :cls     => "IN",
                :type    => "A",
                :address => "10.1.2.3"
        )

  rr = Net::DNS::RR.new(
                :name => "foo.example.com",
                :rdata => "10.1.2.3"
        )

Name and data are required; all the others fields are optionals like we‘ve seen before. The data field can be specified either with the right name of the resource (+:address+ in the example above) or with the generic key +:rdata+. Consult documentation to find the exact name for the resource in each subclass.

Return a new RR object of the correct type (like Net::DNS::RR::A if the type is A) from a binary string, usually obtained from network stream.

This method is used when parsing a binary packet by the Packet class.

Same as RR.parse, but takes an entire packet binary data to perform name expansion. Default when analizing a packet just received from a network stream.

Return an instance of appropriate class and the offset pointing at the end of the data parsed.

Public Instance methods

Class accessor

Return the RR object in binary data format, suitable for using in network streams, with names compressed. Must pass as arguments the offset inside the packet and an hash of compressed names.

This method is to be used in other classes and is not intended for user space programs.

TO FIX in one of the future releases

Return the RR object in binary data format, suitable for using in network streams.

  raw_data = rr.data
  puts "RR is #{raw_data.size} bytes long"

Returns a human readable representation of this record. The value is always a String.

  mx = Net::DNS::RR.new("example.com. 7200 MX 10 mailhost.example.com.")
  #=> example.com.            7200    IN      MX      10 mailhost.example.com.

Data belonging to that appropriate class, not to be used (use real accessors instead)

Returns an Array with all the attributes for this record.

  mx = Net::DNS::RR.new("example.com. 7200 MX 10 mailhost.example.com.")
  mx.to_a
  #=> ["example.com.", 7200, "IN", "MX", "10 mailhost.example.com."]

Returns a String representation of this record.

  mx = Net::DNS::RR.new("example.com. 7200 MX 10 mailhost.example.com.")
  mx.to_s
  #=> "example.com.            7200    IN      MX      10 mailhost.example.com."

Type accessor

[Validate]