...
sub walkHash
{
    my $h = shift;
    my $container = shift;

    foreach my $key (keys %$h)
    {
        if($key ne 'Leaf' && ref $h->{$key} )
        {
            $container->{KEYS} .= $container->{KEYS} ? "/$key" : $key;
            walkHash($h->{$key}, $container);
        }
        else
        {
            #Process hash under 'LEAF' key here.
            print Dumper($container);
            $container->{KEYS} =~ s#/[^/]+$##;   # remove last entry
        }
    }
}
...