NAME
   Net::DNS::SPF::Expander

DESCRIPTION
   This module expands DNS SPF records, so you don't have to. The problem
   is that you only get 10 per SPF record, and recursions count against
   you. Your record won't validate.

   Let's say you start with this as an SPF record:

       @   TXT   "v=spf1 include:_spf.google.com include:sendgrid.net a:hq1.campusexplorer.com a:hq2.campusexplorer.com a:mail2.campusexplorer.com ~all"

   You go to http://www.kitterman.com/spf/validate.html and check this
   record. It passes validation. But later you come back and add
   salesforce, so that you now have:

       @   TXT   "v=spf1 include:_spf.google.com include:sendgrid.net include:salesforce.com a:hq1.campusexplorer.com a:hq2.campusexplorer.com a:mail2.campusexplorer.com ~all"

   And now your record fails validation.

       _spf.google.com takes 3 lookups.
           _spf1.google.com
           _spf2.google.com
           _spf3.google.com
       sendgrid.net takes 1 lookup.
           _sendgrid.biz
       hq1 takes 1 lookup.
       hq2 takes 1 lookup.
       mail2 takes 1 lookup.

   Salesforce adds:

       _spf.google.com (3 you already did)
           _spf1.google.com
           _spf2.google.com
           _spf3.google.com
       mx takes 4 lookups.
           salesforce.com.s8a1.psmtp.com.
           salesforce.com.s8a2.psmtp.com.
           salesforce.com.s8b1.psmtp.com.
           salesforce.com.s8b2.psmtp.com.

   So now instead of 7 you have 14. The common advice is to expand them,
   and that is a tedious process. It's especially tedious when, say,
   salesforce changes their mx record.

   So this module and the accompanying script attempt to automate this
   process for you.

SYNOPSIS
   Using the script:

       myhost:~/ $ dns-dpf-expander --input_file zone.db
       myhost:~/ $ ls
        zone.db   zone.db.new   zone.db.bak

   Using the module:

       {
           package MyDNSExpander;

           use Net::DNS::SPF::Expander;

           my $input_file = '/home/me/project/etc/zone.db';
           my $expander = Net::DNS::SPF::Expander->new(
               input_file => $input_file
           );

           my $string = $expander->write;

           1;
       }

CONFIGURABLE ATTRIBUTES
 input_file
   This is the path and name of the zonefile whose SPF records you want to
   expand. It must be a valid Net::DNS::Zonefile zonefile.

 output_file
   The path and name of the output file. By default, we tack ".new" onto
   the end of the original filename.

 backup_file
   The path and name of the backup file. By default, we tack ".bak" onto
   the end of the original filename.

 nameservers
   A list of nameservers that will be passed to the resolver.

 parsed_file
   The Net::DNS::Zonefile object created from the input_file.

 to_expand
   An arrayref of regexes that we will expand. By default we expand a, mx,
   include, and redirect records. Configurable.

 to_copy
   An arrayref of regexes that we will simply copy over. By default we will
   copy ip4, ip6, ptr, and exists records. Configurable.

 to_ignore
   An arrayref of regexes that we will ignore. By default we ignore ?all,
   exp, v=spf1, and ~all.

 maximum_record_length
   We leave out the protocol declaration and the trailing ~all while we are
   expanding records, so we need to subtract their length from our length
   calculation.

 ttl
   Default time to live is 10 minutes. Configurable.

 origin
   The origin of the zonefile. We take it from the zonefile, or you can set
   it if you like.

PRIVATE ATTRIBUTES
 _input_file
   The IO::All object created from the input_file.

 _resource_records
   An arrayref of all the Net::DNS::RR resource records found in the entire
   parsed_file.

 _spf_records
   An arrayref of the Net::DNS::RR::TXT or Net::DNS::RR::SPF records found
   in the entire parsed_file.

 _resolver
   What we use to do the DNS lookups and expand the records. A
   Net::DNS::Resolver object. You can still set environment variables if
   you want to change the nameserver it uses.

 _expansions
   This is a hashref representing the expanded SPF records. The keys are
   the names of the SPF records, and the values are hashrefs. Those are
   keyed on the include, and the values are arrayrefs of the expanded
   values. There is also a key called "elements" which gathers all the
   includes into one place, e.g.,

       "*.test_zone.com" => {
           "~all"   => undef,
           elements => [
               "ip4:216.239.32.0/19", "ip4:64.233.160.0/19",
               "ip4:66.249.80.0/20",  "ip4:72.14.192.0/18",
               ...
           ],
           "include:_spf.google.com" => [
                "ip4:216.239.32.0/19",
                "ip4:64.233.160.0/19",
                ...
           ],
           "ip4:96.43.144.0/20" => [ "ip4:96.43.144.0/20" ],
           "v=spf1"             => undef
         }

   They are alpha sorted in the final results for predictability in tests.

 _lengths_of_expansions
   We need to know how long the expanded record would be, because SPF
   records should be less than 256 bytes. If the expanded record would be
   longer than that, we need to split it into pieces.

 _record_class
   What sort of records are SPF records? IN records.

BUILDERS
 _build_resolver
   Return a Net::DNS::Resolver. Any nameservers will be passed through to
   the resolver.

 _build_origin
   Extract the origin from parsed_file.

 _build_expansions
 _build_backup_file
   Tack a ".bak" onto the end of the input_file.

 _build__input_file
   Turn the string input_file into a filehandle with IO::All.

 _build_output_file
   Tack a ".new" onto the end of the input_file.

 _build_parsed_file
   Turn the IO::All filehandle into a Net::DNS::Zonefile object, so that we
   can extract the SPF records.

 _build_resource_records
   Extract all the resource records from the Net::DNS::Zonefile.

 _build__spf_records
   Grep through the _resource_records to find the SPF records. They can be
   both "TXT" and "SPF" records, so we search for the protocol string,
   v=spf1.

 _build__lengths_of_expansions
   Calculate the length of each fully expanded SPF record, because they
   can't be longer than 256 bytes. We have to split them up into multiple
   records if they are.

PUBLIC METHODS
 write
   This is the only method you really need to call. This expands all your
   SPF records and writes out the new and the backup files.

   Returns a scalar string of the data written to the file.

 new_spf_records
   In case you want to see how your records were expanded, this returns the
   hashref of Net::DNS::RR objects used to create the new records.

PRIVATE METHODS
 _normalize_component
   Each component of an SPF record has a prefix, like include:, mx:, etc.
   Here we chop off the prefix before performing the lookup on the value.

 _perform_expansion
   Expand a single SPF record component. This returns either undef or the
   full SPF record string from Net::DNS::RR::TXT->txtdata.

 _expand_spf_component
   Recursively call _perform_expansion for each component of the SPF
   record. This returns an array consisting of the component, e.g.,
   include:salesforce.com, and an arrayref consisting of its full
   expansion, e.g.,

       [
           "ip4:216.239.32.0/19",
           "ip4:64.233.160.0/19",
           ...
           "ip6:2c0f:fb50:4000::/36"
       ]

 _expand
   Create the _expansions hashref from which we generate new SPF records.

 _extract_expansion_elements
   Filter ignored elements from component expansions.

 _new_records_from_arrayref
   The full expansion of a given SPF record is contained in an arrayref,
   and if the length of the resulting new SPF record would be less than the
   maximum_record_length, we can use this method to make new Net::DNS::RR
   objects that will later be stringified for the new SPF record.

 _new_records_from_partition
   The full expansion of a given SPF record is contained in an arrayref,
   and if the length of the resulting new SPF record would be greater than
   the maximum_record_length, we have to jump through some hoops to
   properly split it into new SPF records. Because there will be more than
   one, and each needs to be less than the maximum_record_length. We do our
   partitioning here, and then call _new_records_from_arrayref on each of
   the resulting partitions.

 _get_single_record_string
   Stringify the Net::DNS::RR::TXT records when they will fit into a single
   SPF record.

 _normalize_record_name
   Net::DNS uses fully qualified record names, so that new SPF records will
   be named *.domain.com, and domain.com, instead of * and @. I prefer the
   symbols. This code replaces the fully qualified record names with
   symbols.

 _get_multiple_record_strings
   Whereas a single new SPF record needs to be concatenated from the
   stringified Net::DNS::RR::TXTs, and have the trailing ~all added,
   multiple new SPF records do not need that. They need to be given special
   _spf names that will then be included in "master" SPF records, and they
   don't need the trailing ~all.

 _get_master_record_strings
   Create our "master" SPF records that include the split _spf records
   created in _get_multiple_record_strings, e.g.,

       *    600    IN    TXT    "v=spf1 include:_spf1.test_zone.com include:_spf2.test_zone.com ~all"

 _new_records_lines
   Assemble the new DNS zonefile from the lines of the original, comment
   out the old SPF records, add in the new lines, and append the end of the
   original.

AUTHOR
   Amiri Barksdale <[email protected]>

 CONTRIBUTORS
   Neil Bowers <[email protected]>

   Chris Weyl <[email protected]>

COPYRIGHT
   Copyright (c) 2015 Campus Explorer, Inc.

LICENSE
   This library is free software; you can redistribute it and/or modify it
   under the same terms as Perl itself.

SEE ALSO
   Net::DNS

   Net::DNS::RR::TXT

   MooseX::Getopt

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