Wireguard: Add multiple clients script. Based on angristan/wireguard-install

add-users.sh

#!/bin/bash

# This script is based on code from https://github.com/angristan/wireguard-install and might not work if you use another script. Use it on your own responsibility.
# Usage: `./add-users.sh "marty;emmet;biff"`

# Check if WireGuard is already installed and load params
if [[ -e /etc/wireguard/params ]]; then
	source /etc/wireguard/params
else
	echo "wireguard is not installed, please install using this script: https://github.com/angristan/wireguard-install"
fi

# parse vars
for CLIENT_NAME in $(echo $1 | tr ";" "\n")
do
  # check if client already exist
  CLIENT_EXISTS=$(grep -c -E "^### Client ${CLIENT_NAME}\$" "/etc/wireguard/${SERVER_WG_NIC}.conf")
  if [[ ${CLIENT_EXISTS} != '0' ]]; then
  	echo ""
  	echo "A client with the specified name was already created, please choose another name."
  	echo ""
  	exit 1
  fi

  echo "creating config for user: ${CLIENT_NAME}" 

  ENDPOINT="${SERVER_PUB_IP}:${SERVER_PORT}"

  for DOT_IP in {2..254}; do
  	DOT_EXISTS=$(grep -c "${SERVER_WG_IPV4::-1}${DOT_IP}" "/etc/wireguard/${SERVER_WG_NIC}.conf")
  	if [[ ${DOT_EXISTS} == '0' ]]; then
  		break
  	fi
  done

  if [[ ${DOT_EXISTS} == '1' ]]; then
  	echo ""
  	echo "The subnet configured supports only 253 clients."
  	exit 1
  fi

  BASE_IP=$(echo "$SERVER_WG_IPV4" | awk -F '.' '{ print $1"."$2"."$3 }')
  CLIENT_WG_IPV4="${BASE_IP}.${DOT_IP}"

  BASE_IP=$(echo "$SERVER_WG_IPV6" | awk -F '::' '{ print $1 }')
  CLIENT_WG_IPV6="${BASE_IP}::${DOT_IP}"



	# Generate key pair for the client
	CLIENT_PRIV_KEY=$(wg genkey)
	CLIENT_PUB_KEY=$(echo "${CLIENT_PRIV_KEY}" | wg pubkey)
	CLIENT_PRE_SHARED_KEY=$(wg genpsk)

	# Home directory of the user, where the client configuration will be written
	if [ -e "/home/${CLIENT_NAME}" ]; then
		# if $1 is a user name
		HOME_DIR="/home/${CLIENT_NAME}"
	elif [ "${SUDO_USER}" ]; then
		# if not, use SUDO_USER
		if [ "${SUDO_USER}" == "root" ]; then
			# If running sudo as root
			HOME_DIR="/root"
		else
			HOME_DIR="/home/${SUDO_USER}"
		fi
	else
		# if not SUDO_USER, use /root
		HOME_DIR="/root"
	fi

	# Create client file and add the server as a peer
	echo "[Interface]
	PrivateKey = ${CLIENT_PRIV_KEY}
	Address = ${CLIENT_WG_IPV4}/32,${CLIENT_WG_IPV6}/128
	DNS = ${CLIENT_DNS_1},${CLIENT_DNS_2}

	[Peer]
	PublicKey = ${SERVER_PUB_KEY}
	PresharedKey = ${CLIENT_PRE_SHARED_KEY}
	Endpoint = ${ENDPOINT}
	AllowedIPs = 0.0.0.0/0,::/0" >>"${HOME_DIR}/${SERVER_WG_NIC}-client-${CLIENT_NAME}.conf"

	# Add the client as a peer to the server
	echo -e "\n### Client ${CLIENT_NAME}
	[Peer]
	PublicKey = ${CLIENT_PUB_KEY}
	PresharedKey = ${CLIENT_PRE_SHARED_KEY}
	AllowedIPs = ${CLIENT_WG_IPV4}/32,${CLIENT_WG_IPV6}/128" >>"/etc/wireguard/${SERVER_WG_NIC}.conf"

	wg syncconf "${SERVER_WG_NIC}" <(wg-quick strip "${SERVER_WG_NIC}")

	echo "It is also available in ${HOME_DIR}/${SERVER_WG_NIC}-client-${CLIENT_NAME}.conf"
done