lambda_ip_ranges.rb

require 'ipaddr'

ec2_ranges = %w_
   103.4.8.0/21
175.41.192.0/18
 176.32.64.0/19
  176.34.0.0/19
 176.34.32.0/19
 46.51.224.0/19
  52.192.0.0/15
  52.196.0.0/14
   52.68.0.0/15
 52.95.243.0/24
52.95.255.48/28
  54.150.0.0/16
  54.168.0.0/16
  54.178.0.0/16
  54.199.0.0/16
  54.238.0.0/16
  54.248.0.0/15
  54.250.0.0/16
   54.64.0.0/15
   54.92.0.0/17
   54.95.0.0/16
_.map{|range| IPAddr.new(range) }


# $ dig +short lambda.ap-northeast-1.amazonaws.com a
# 52.69.6.111
# 52.69.23.0
# 52.69.25.229
# 52.69.54.22
# 52.69.67.28
# 52.69.67.226
# 54.64.249.58
# 54.249.77.229

lambda_ips = %w_
52.69.6.111
52.69.23.0
52.69.25.229
52.69.54.22
52.69.67.28
52.69.67.226
54.64.249.58
54.249.77.229
_.map{|l| IPAddr.new(l) }

lambda_ips.each do |l|
  catch(:found) do
    ec2_ranges.each_with_index do |range, i|
      if range.include?(l)
        prefixlen = 32 - (2 ** 32 - 1 - range.instance_eval{ @mask_addr }).to_s(2).length
        puts "#{l} is included in #{range.to_s}/#{prefixlen}"
        throw(:found)
      end
    end
    puts "#{l} isn't included in any of ip ranges"
  end
end

# 52.69.6.111   is included in 52.68.0.0/15
# 52.69.23.0    is included in 52.68.0.0/15
# 52.69.25.229  is included in 52.68.0.0/15
# 52.69.54.22   is included in 52.68.0.0/15
# 52.69.67.28   is included in 52.68.0.0/15
# 52.69.67.226  is included in 52.68.0.0/15
# 54.64.249.58  is included in 54.64.0.0/15
# 54.249.77.229 is included in 54.248.0.0/15