Enable Only Specific Network Interfaces (macOS)

networkonly.ruby

#!/usr/bin/env ruby

# this script will enable only the specified network interface
# a list of interfaces which were enabled will be recorded into 
# the file /tmp/network_interfaces_[datestamp].txt

# released under the GNU GPL version 3 or later
# copyright henri shustak 2021

# See URL below for information on setting up networksetup access for non admin users
# https://github.com/henri/handy-alias/wiki/Network-Service-Order-%3A-Mac-OS-X

# version 1.0 - intitial version
# version 1.1 - improved compatability with more recent versions of macOS around security.
# version 1.2 - bug fix
# version 1.2 - added comment support when loading a file


@SHOW_PATH_TO_SAVED_INTERFACES = true
@ACTIVE_INTERFACES = []
@JUST_LIST_INTERFACES = false


req_arg_num = 1
if ARGV[0] == "-l" then
  req_arg_num = 2
end
if ARGV[0] == "-i" then
  @JUST_LIST_INTERFACES = true
end

if ( ARGV.length < req_arg_num.to_i || ARGV.length > req_arg_num.to_i ) then
  puts "Sorry, too few or two many arguments :("
  puts "   usage examples : "
  puts "        enable single interface :              networkonly.ruby <network-to-keep-running>"
  puts "        enable interfaces listed in a file :   networkonly.ruby -l <file-to-load-interfaces-from.txt>"
  puts "        show names of availible interfaces :   networkonly.ruby -i"
  exit
end


def check_if_network_interface_present(nip)
  if `sudo /usr/sbin/networksetup -listallnetworkservices | tail -n +2 | tr -d "*" | grep "#{nip}" >> /dev/null ; echo $?`.chomp == "0" then
    return 0
  else
    puts "The network interface \"#{nip.to_s}\" was not found on this system."
    exit -10
  end
end


def active_interfaces_update
  active_interfaces_raw = `sudo /usr/sbin/networksetup -listallnetworkservices | grep -v "*"`
  @ACTIVE_INTERFACES = active_interfaces_raw.split("\n") 
end


def is_only_active_interface(interface_name)
  active_interfaces_update
  if @ACTIVE_INTERFACES.size == 1 then
    if @ACTIVE_INTERFACES[0].to_s == interface_name.to_s then return true
    else return false end else return false 
  end
end


def is_only_active_interface_with_exit(interface_name)
  if is_only_active_interface("#{interface_name}") != true
    puts "    Requested interface is not the only active interface."
    exit -1
  end
end


def enable_interface(interface_name)
  `networksetup -setnetworkserviceenabled "#{interface_name}" on`
  puts `echo $?`
end


def make_active_only(make_active_array)

  # check that all interfaces requested to be active exist
  make_active_array.each do | interface | 
    check_if_network_interface_present(interface) 
  end

  # build list avaible interfaces (we can turn off or on)
  avalible_interfaces_raw = `sudo /usr/sbin/networksetup -listallnetworkservices | tail -n +2 | tr -d "*"`
  availble_interfaces = avalible_interfaces_raw.split("\n")

  # make only the - make_active_array - interface(s) active
  availble_interfaces.each do | interface |
    if not make_active_array.include?("#{interface}") then
      # turn off the network interface
      `sudo /usr/sbin/networksetup -setnetworkserviceenabled "#{interface}" off`
      puts "turning off interface : #{interface}"
    else
      # turn on the network interface
      `sudo /usr/sbin/networksetup -setnetworkserviceenabled "#{interface}" on`
      puts "turning on interface : #{interface}"
    end
  end
end

#just show the available interfaces and exit
if @JUST_LIST_INTERFACES then
  availible_interfaces_raw = `sudo /usr/sbin/networksetup -listallnetworkservices | tail -n +2 | tr -d "*"`
  puts ""
  puts availible_interfaces_raw
  puts ""
  exit 0
end

date_stamp = `date "+%Y-%m-%d_%H-%M-%S"`.chomp
active_interfaces_raw = `sudo /usr/sbin/networksetup -listallnetworkservices | grep -v "*" | tee "/tmp/network_interfaces_#{date_stamp}.txt"`
active_interfaces = active_interfaces_raw.split("\n")
if @SHOW_PATH_TO_SAVED_INTERFACES then
  puts ""
  puts "active interfaces saved to : /tmp/network_interfaces_#{date_stamp}.txt"
  puts ""
end


if req_arg_num.to_i == 1 then
  # just turning things off
  keep_on = ARGV[0]
  make_active_only([keep_on.to_s])
  active_interfaces_update
  if is_only_active_interface("#{keep_on}") != true
    puts "Some other interfaces are still active!"
    exit -1
  end
else
  # load files and making them active and making everything else inactive
  interfaces_to_activate = []
  File.open("#{ARGV[1]}") do |load_file|
    load_file.each_line do |line|
      if ! line.strip.start_with?("#") then
        file_line = line.chomp.split('#')
        to_activate = file_line.first.strip
        puts to_activate.inspect
        interfaces_to_activate << to_activate.chomp
      end
    end
  end
  make_active_only(interfaces_to_activate)
end


exit 0