Calculates the prefix assigned to the ASN based on the ASN.

ixp_frnte_dn42_prefix.rb

# see https://explorer.dn42.dev/#/inet6num/fde0:93fa:7a0:2::_64

if ! ARGV[0]
    puts "arg 0 is the asn"
end

asn = ARGV[0]
asn_bin = asn.to_i.to_s(2)
asn_low16 = asn_bin[0...16].to_i(2).to_s(16)
asn_high16 = asn_bin[16..-1].to_i(2).to_s(16)

puts "ASN: #{asn}"
puts "Subnet is fde0:93fa:7a0:2::/64"
puts "For the AS usable subnet: fde0:93fa:7a0:2:0:#{asn_low16}:#{asn_high16}:/112"