analyzing mac addresses rejected by foreman v1.14's new validation logic (excluding non-unicast MAC addresses)

foreman_mac_validation_testing.rb

require 'ipaddr'
require 'socket'

IP_REGEXP  ||= /\A((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}\z/
MAC_REGEXP ||= /\A([a-f0-9]{1,2}:){5}[a-f0-9]{1,2}\z/i
MAC_REGEXP_64BIT ||= /\A([a-f0-9]{1,2}:){19}[a-f0-9]{1,2}\z/i
HOST_REGEXP ||= /\A(([a-z0-9]|[a-z0-9][a-z0-9\-]*[a-z0-9])\.)*([a-z0-9]|[a-z0-9][a-z0-9\-]*[a-z0-9])\z/
MASK_REGEXP ||= /\A((255.){3}(0|128|192|224|240|248|252|254))|((255.){2}(0|128|192|224|240|248|252|254).0)|(255.(0|128|192|224|240|248|252|254)(.0){2})|((128|192|224|240|248|252|254)(.0){3})\z/


def validate_mac(mac)
      return false if mac.nil?

      case mac.size
      when 17
        return true if (mac =~ MAC_REGEXP)
      when 59
        return true if (mac =~ MAC_REGEXP_64BIT)
      end

      false
end

def multicast_mac?(mac)
      return false unless validate_mac(mac)

      # Get the first byte
      msb = mac.tr('.:-', '').slice(0..1).to_i(16)

      # Is least significant bit set?
      msb & 0b1 == 1
end

def broadcast_mac?(mac)
      return false unless validate_mac(mac)
      mac.downcase == 'ff:ff:ff:ff:ff:ff'
end

    # validates the mac and raises an error
def validate_mac!(mac)
      raise Error, "Invalid MAC #{mac}" unless validate_mac(mac)
      mac
end

test_macs = [
  'aa:bb:cc:dd:ee:ff',
  '00:bb:cc:dd:ee:ff',
  'b7:35:bc:ba:71:e8',
  '39:52:a6:55:ea:80',
  '40:52:a6:55:ea:80',
  '41:52:a6:55:ea:80',
  '4a:52:a6:55:ea:80',
  '4b:52:a6:55:ea:80',
  '4d:52:a6:55:ea:80',
  '4f:52:a6:55:ea:80',
]


for test in test_macs
    test_slice = test.tr('.:-', '').slice(0..1)
    test_int = test_slice.to_i(16)
    puts "[" + test + "]"
    puts test_slice
    puts test_int
    puts "valid: " + validate_mac(test).to_s
    puts "broadcast: " + broadcast_mac?(test).to_s
    puts "multicast: " + multicast_mac?(test).to_s
    puts ''
end

puts "it turns out i was auto-generating MAC addresses without any regard for their binary structure"
puts "and often generating MACs with an odd 2nd hex digit of the first octet, thus making the least"
puts "significant bit equal to 1 and pissing off foreman's validator."
puts ""
puts "womp, womp womp...."
puts ""