A short shell script to manage wireguard clients

wg_client.sh

#!/bin/bash

show_usage() {
    echo "Usage: $0 [list|add|show|remove] [client_name]"
    echo "   list     lists all registered peers"
    echo "   add      adds a new client with the given name to wireguard"
    echo "   show     shows the wireguard configuration for the client with the given name"
    echo "   remove   removes a client from wireguard"
}

list_clients() {
    cd /etc/wireguard/peers
    regex="wg-peer-[0-9]+-(.*)$"
    for d in *; do
        if [[ $d =~ $regex ]]; then
            echo "${BASH_REMATCH[1]}"
        fi
    done
}

add_client() {
    cd /etc/wireguard/peers
    regex="wg-peer-[0-9]+-${1}$"
    for d in *; do
        if [[ $d =~ $regex ]]; then
            echo "${1} already registered as peer"
            exit
        fi
    done

    id="0"
    for i in $(seq -f "%03g" 2 255); do
        regex="wg-peer-${i}-.*"
        for d in *; do
            if [[ $d =~ $regex ]]; then
                # peer with id $i already exists
                continue 2
            fi
        done

        # found lowest usable id
        id="$i"
        break
    done

    if [ "$id" -eq 0 ]; then
        echo "255 peers already registered, delete peers first"
        exit
    fi

    name="wg-peer-${id}-${1}"
    echo "creating keys for ${name}"

    umask 077
    mkdir "$name"
    cd "$name"
    wg genkey | tee "peer.key" | wg pubkey >"peer.pub"
    wg genpsk >"peer.psk"

    id=$(expr $id + 0)
    echo "[Peer]" >peer.conf
    echo "PublicKey = $(cat "peer.pub")" >>peer.conf
    echo "PresharedKey = $(cat "peer.psk")" >>peer.conf
    echo "AllowedIPs = 10.100.0.${id}/32, fd08:4711::${id}/128" >>peer.conf

    echo "[Interface]" >client.conf
    echo "Address = 10.100.0.${id}/32, fd08:4711::${id}/128" >>client.conf
    echo "DNS = 10.100.0.1" >>client.conf
    echo "PrivateKey = $(cat "peer.key")" >>client.conf
    echo "" >>client.conf
    echo "[Peer]" >>client.conf
    echo "AllowedIPs = 10.100.0.0/24, fd08::/64" >>client.conf
    echo "Endpoint = 34.73.216.192:47111" >>client.conf
    echo "PersistentKeepalive = 25" >>client.conf
    echo "PublicKey = $(cat "../../server.pub")" >>client.conf
    echo "PresharedKey = $(cat "peer.psk")" >>client.conf

    # qrencode -t ansiutf8 -r client.conf
    show_peer $1
    update_wg_conf
}

update_wg_conf() {
    cd /etc/wireguard
    cat server.conf >wg0.conf

    for d in $(ls peers); do
        echo "" >>wg0.conf
        cat "peers/${d}/peer.conf" >>wg0.conf
    done

    systemctl restart wg-quick@wg0
}

show_peer() {
    cd /etc/wireguard/peers
    regex="wg-peer-[0-9]+-${1}$"
    for d in *; do
        if [[ $d =~ $regex ]]; then
            qrencode -t ansiutf8 -r "${d}/client.conf"
            return
        fi
    done

    echo "peer ${1} not found"
    return
}

remove_peer() {
    cd /etc/wireguard/peers
    regex="wg-peer-[0-9]+-${1}$"
    for d in *; do
        if [[ $d =~ $regex ]]; then
            echo "removing ${d}"
            rm -r $d
            update_wg_conf
            return
        fi
    done

    echo "${1} not found"
}

if [ "$EUID" -ne 0 ]; then
    echo "Please run as root"
    exit
fi

if [ "$#" -lt 1 ]; then
    show_usage
    exit
fi

case $1 in
list)
    list_clients
    ;;
add)
    add_client $2
    ;;
show)
    show_peer $2
    ;;
remove)
    remove_peer $2
    ;;
*)
    echo "unknown sub-command ${1}"
    echo ""
    show_usage
    exit
    ;;
esac