gistfile1.txt

#!/usr/bin/env ruby
require "rubygems"
require "daemons"

INTERFACE = "wlan0"
TEST_ADDRESSES = %w(http://www.google.pl/ http://www.yahoo.com/ http://www.msn.com/)
TEST_TIMEOUT = 5
SCAN_TIMEOUT = 1
CONNECTION_TIMEOUT = 30
LOOP_DELAY = 60
IP_RANGE = "10.2.1.*"
MAC_ADDRESSES_FILE = "/home/kuba/macswapper/mac_addresses"

def change_mac(mac_address)
  `ifconfig #{INTERFACE} hw ether #{mac_address}`
end

def network_manager(command)
  `dbus-send --print-reply --system --dest=org.freedesktop.NetworkManager /org/freedesktop/NetworkManager org.freedesktop.NetworkManager.#{command}`
end

def dump_arp_table
  `nmap -sP -n #{IP_RANGE}`.scan(/(?:[a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}/)
end

def connection_to(address)
  result = `curl -sm#{TEST_TIMEOUT} #{address}`
  result if $?.exitstatus.zero?
end

def ping_scan
  [].tap do |mac_addresses|
    IP_ADDRESSES.each_slice(MAX_PROCESSES) do |ip_addresses|
      threads = ip_addresses.map { |ip_address| Thread.new { arping(ip_address) } }
      threads.map(&:value).each { |mac_address| mac_addresses << mac_address if mac_address }
    end
  end
end

def load_mac_address_tables
  open(MAC_ADDRESSES_FILE) do |file|
    file.readlines.map do |line|
      tries, mac_address = line.split(" ").reverse
      [tries.to_i, mac_address]
    end
  end
end

def save_mac_address_tables(mac_address_tables)
  open(MAC_ADDRESSES_FILE, "w") do |file|
    file.puts(mac_address_tables.sort.reverse.map { |mac_address_table| mac_address_table.reverse.join(" ").downcase } )
  end
end

def connection_working?
  TEST_ADDRESSES.map { |address| connection_to(address) }.compact.uniq.size == TEST_ADDRESSES.size
end

def reconnect(mac_address_tables)
  mac_address_tables.sort.reverse.find do |mac_address_table|
    network_manager("sleep")
    change_mac(mac_address_table[1])
    network_manager("wake")
    sleep(CONNECTION_TIMEOUT)
    connection_working?.tap do |working|
      mac_address_table[0] += working ? 1 : -1
      save_mac_address_tables(mac_address_tables)
    end
  end
end

def add_new_mac_addresses(mac_address_tables)
  dump_arp_table.each do |mac_address|
    mac_address_tables << [0, mac_address.downcase] unless mac_address_tables.find do |mac_address_table|
      mac_address_table.last.downcase == mac_address.downcase
    end
  end
  save_mac_address_tables(mac_address_tables)
end

Daemons.run_proc("macswapper.rb") do
  mac_address_tables = load_mac_address_tables
  loop do
    if connection_working?
      add_new_mac_addresses(mac_address_tables)
    else
      reconnect(mac_address_tables)
    end
    sleep(LOOP_DELAY)
  end
end