OpenVPN adding static ip for client dynamically based on a script

cn flag

In my VPN logic all of my client certificates have the folowing CN template: where number is between 2-65536

For each CN I add a config file which looks like so:

$ cat

So basically based on the CN number area I configure the static ip in the relevant file, conversion from number to ip logic:

$ python3 -c "print('10.22.{}.{}'.format(*divmod(65501, 256)))"

Is there a way to do it dynamically in the config with a script or something else, instead of adding client config file everytime?

cn flag

Reading the manuall carefully I saw it's possible to add a script with the ability to dynamically change the config per client using the --client-connect flag.

I added the following config line to my server.conf file:

client-connect /etc/openvpn/

and the file content is the following bash script:

#!/usr/bin/env bash


function get_client_num() {
  # returns the client number from the `common_name` env variable
  local cn_arr=(${common_name//./ })
  local cn_arr_first=${cn_arr[0]}
  echo "${cn_arr_first}"

function generate_client_ip() {
  # returns generated remote client ip from the `ifconfig_pool_remote_ip` env variable and client_num
  local ifconfig_remote_arr=(${ifconfig_pool_remote_ip//./ })

  local client_num=$(get_client_num)
  local remote_ip_octet_1=${ifconfig_remote_arr[0]}
  local remote_ip_octet_2=${ifconfig_remote_arr[1]}
  local remote_ip_octet_3=$((client_num/256))
  local remote_ip_octet_4=$((client_num%256))

  echo "${remote_ip_octet_1}.${remote_ip_octet_2}.${remote_ip_octet_3}.${remote_ip_octet_4}"

  echo "ifconfig-push ${remote_ip}" > "${DYNAMIC_GENERATED_CONFIG_PATH}"

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