Module: ArpRevolver

Defined in:
lib/arp_revolver.rb,
lib/arp_revolver/version.rb

Defined Under Namespace

Classes: Error

Constant Summary collapse

VERSION = 
"0.1.1"

Class Method Summary collapse

Class Method Details

.current_mac_addr(host) ⇒ Object 



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# File 'lib/arp_revolver.rb', line 78

def current_mac_addr(host)
  IO.popen("arp -e") do |io|
    info = io.read.lines.select { |line| line.match(/#{host}/) }

    info.first&.split(" ")&.[](2)
  end
end

.health_trigger(interface, host) ⇒ Object 



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# File 'lib/arp_revolver.rb', line 70

def health_trigger(interface, host)
  IO.popen("arping -c #{revolver_config["pings"]} -I #{interface} #{host}") do |io|
    result = io.read.lines.last.strip.match(/Received\ (?<num>\d)\ response\(s\)/)

    result[:num].to_i >= revolver_config["online_threshold"]
  end
end

.revolver_config ⇒ Object

Raises:

  • (StandardError) 


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# File 'lib/arp_revolver.rb', line 22

def revolver_config
  file_path = "/etc/arp-revolver.yml"

  raise StandardError, "config file must be 640 mode" unless File.stat(file_path).mode.to_s(8)[3..5] == "640"

  @revolver_config ||= YAML.load_file(file_path)

  raise StandardError, "config file is needed" unless @revolver_config

  @revolver_config
end

.send_sentry(message, level: :error) ⇒ Object 



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# File 'lib/arp_revolver.rb', line 86

def send_sentry(message, level: :error)
  return puts(message) unless (sentry_dsn = revolver_config["sentry_dsn"])

  Raven.configure do |config|
    config.dsn = revolver_config["sentry_dsn"]
  end

  Raven.capture_message(message, level: level)
end

.trigger ⇒ Object 



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# File 'lib/arp_revolver.rb', line 34

def trigger
  revolver_config["hosts"]&.each do |host, config|
    return puts "Info: #{host} connection is OK" if health_trigger(config["interface"], host)

    error_msg = "Error: #{host} connection Fail, try to change the MAC address."

    puts error_msg

    send_sentry(error_msg, level: :error)

    old_mac_addr = config["mac_addrs"].delete(current_mac_addr(host))

    config["mac_addrs"].each do |mac_addr|
      IO.popen "echo $(arp -s #{host} #{mac_addr})"

      if health_trigger(config["interface"], host)
        puts "ARP Revolver: switch mac address from <#{old_mac_addr}> to <#{mac_addr}> for HOST (#{host})"

        return
      else
        error_msg = "Error: #{host}[#{current_mac_addr(host)}] connection Fail, try to change the MAC address."

        puts error_msg
      end
    end

    unless health_trigger(config["interface"], host)
      error_msg = "Error: #{host} connection still Fail, after tried all MAC addresses."

      puts error_msg

      send_sentry(error_msg, level: :error)
    end
  end
end