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# File 'lib/hpc/dns.rb', line 54

def prefix
  if @addr
    # count the number of 1 in binary repr of addr mask
    @mask_addr.to_s(2).count('1')
  else
    nil
  end
end

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# File 'lib/hpc/dns.rb', line 63

def subnets
  if prefix < 16
    STDERR.puts "Unable to calc /24 subnets on networks with cidr prefix #{prefix} < 16"
    return []
  elsif prefix >= 24
    return [ self ]
  end

  begin_addr_i = (@addr & @mask_addr)

  case @family
  when Socket::AF_INET
    end_addr_i = (@addr | (IN4MASK ^ @mask_addr))
  when Socket::AF_INET6
    end_addr_i = (@addr | (IN6MASK ^ @mask_addr))
  else
    raise "unsupported address family"
  end

  begin_addr = clone.set(begin_addr_i, @family)
  end_addr = clone.set(end_addr_i, @family)

  # FIXME: Starting from here, the logic really sucks and only works on ipv4
  # networks whose CIDR prefix is between 16 and 24.

  subnets_a = Array.new()

  network_number = begin_addr.to_s.split('.')[0..1]

  first_subnet = begin_addr.to_s.split('.')[2].to_i
  last_subnet  = end_addr.to_s.split('.')[2].to_i

  (first_subnet..last_subnet).each do |subnet_idx|
    subnet_s = [network_number, subnet_idx, '0'].flatten.join('.')
    subnet = IPAddr.new("#{subnet_s}/24")
    subnets_a << subnet
  end

  return subnets_a

end