#! /usr/bin/perl
use warnings;
use strict;

use XML::LibXML;

my $dom = 'XML::LibXML'->load_xml(location => shift);
my %struct;
for my $ref ($dom->findnodes('/root/ref')) {
    for my $child ($ref->findnodes('*')) {
        push @{ $struct{ $ref->{name} }{ $child->nodeName } },
             { map { $_->nodeName => $_->value } $child->findnodes('@*') };
    }
}

use Data::Dumper; print Dumper \%struct;