f5

#!/usr/bin/env ruby

require 'ostruct'
require 'resolv'
require 'shellwords'
require 'optparse'
require 'socket'

CLIENT_IP_PREFIXS = ["10.161","10.163", "10.133", "72.52"]

DEFAULT_DESITINATIONS = ['0/1','default']

def local_ip_prefix
  Socket.ip_address_list.detect{|intf| intf.ipv4_private?}.ip_address.split('.')[0..1].join('.')
end

def netstat
  route_table = `netstat -nr -f inet`
  route_table.split("\n").slice(4..-1).map do |line|
    route = Shellwords.split(line)
    OpenStruct.new({destination: route[0], gateway: route[1]})
  end
end

def resolve_address(host)
  IPSocket::getaddress(host)
end

def dns_resovers
  Resolv::DNS::Config.default_config_hash[:nameserver].select { |ns| in_client_network?(ns) }
end

def restore
  puts "Restoring route table to default settings...."
  for i in (1..3) do
    `netstat -n flush`
  end

  `ifconfig en0  down`
  `ifconfig en0  up`
end

def delete_route(destination, gateway)
  puts "Deleting route #{destination} : #{gateway}"
  `route delete #{destination} #{gateway}`
end

def add_host_route(destination, gateway)
  puts "Add route #{destination} : #{gateway}"
  `route add -host #{destination} #{gateway}`
end

def add_net_route(destination, gateway)
  puts "Add route #{destination} : #{gateway}"
  `route add -net #{destination} #{gateway}`
end

def in_client_network?(ip)
  CLIENT_IP_PREFIXS.any? { |prefix| ip.start_with?(prefix)}
end

def in_office_network?(ip)
  OFFICE_IP_PREFIXS.any? { |prefix| ip.start_with?(prefix)}
end


def fix
  f5_routes = netstat.select {|route| in_client_network?(route.destination) || in_client_network?(route.gateway) }

  if f5_routes.empty?
    puts "f5 route settings not found, are you connecting to F5 VPN?"
    return 
  end

  puts "start fixing..."
  routes = netstat.select { |route| DEFAULT_DESITINATIONS.include?(route.destination) && in_client_network?(route.gateway) }
  if routes.count == 0
    puts "network routes already fixed"
    exit(0)
  end
  f5_gateway = routes.first.gateway
  office_gateway = netstat.select { |route| DEFAULT_DESITINATIONS.include?(route.destination) && route.gateway.start_with?(local_ip_prefix()) }.first.gateway

  puts "Delete f5 routes..."
  f5_routes.each do |route|
    delete_route(route.destination, route.gateway)
  end

  CLIENT_IP_PREFIXS.each do |prefix|
    add_net_route(prefix, f5_gateway)
  end

  dns_resovers.each  do |ns|
    add_host_route(ns, f5_gateway)
  end

  puts "Seting office network as default route..."
  add_host_route('0/1', office_gateway)

end

options = {}
OptionParser.new do  |opts|
  opts.banner = "Usage: fix [options]"

  opts.on('-r','--restore','Restore route table to default settings') do 
    options[:restore] = true
  end
  
  opts.on('-f', '--fix', 'Patch route table to make f5 vpn work with office network ') do 
    options[:fix] = true
  end

  opts.on('-h', '--help', 'Show this help') do 
    puts opts
    exit
  end
end.parse!

fix if options[:fix]
restore if options[:restore]