Script to randomize wireguard connections

[p1r473]

hey,
here's a script I've been working on to randomize wireguard connections.
Ive set up wireguard clients 1-5 within the asus router gui.
using the script, I can randomize which client to use.
Hope you find it useful!
Im using Mullvad, and ipinfo. Feel free to customize it to your liking

Usage: $0 {start|stop|restart|toggle|status} [dynamic IPs]

#!/bin/sh

### CONFIGURATION ###
#Enter subnets to VPNify in CIDR format, space-delimited
WG_SUBNETS=""

#Enter hosts to VPNify in CIDR format, space-delimited
VPN_WHITELIST_HOSTS=""

#Enter hosts to never VPNify. Routers, access points, etc. in CIDR format, space-delimited
VPN_BLACKLIST_HOSTS=""

STATUS_URL="https://ipv4.am.i.mullvad.net/connected"
ORG_URL="https://ipinfo.io/org?token=XXXXXXXXXXXXX"
WG_TABLES="wgc1 wgc2 wgc3 wgc4 wgc5"
max_timeout=5
connect_timeout=5
DYNAMIC_HOSTS_FILE="/tmp/mullvad_dynamic_hosts"
DYNAMIC_WHITELIST_HOSTS=""
last_wg=""

load_dynamic_hosts() {
    if [ -f "$DYNAMIC_HOSTS_FILE" ]; then
        DYNAMIC_WHITELIST_HOSTS=$(cat "$DYNAMIC_HOSTS_FILE")
    else
        DYNAMIC_WHITELIST_HOSTS=""
    fi
}

save_dynamic_hosts() {
    echo "$DYNAMIC_WHITELIST_HOSTS" > "$DYNAMIC_HOSTS_FILE"
}

get_vpn_routes() {
    ip rule show | grep -o 'lookup wgc[1-5]' | sed 's/lookup //g' | sort -u
}

randomize_wg() {
    AVAILABLE_WG=""
    for wg in $WG_TABLES; do
        if [ "$wg" != "$last_wg" ]; then
            AVAILABLE_WG="$AVAILABLE_WG $wg"
        fi
    done

    set -- $AVAILABLE_WG
    COUNT=$#

    if [ "$COUNT" -eq 0 ]; then
        set -- $WG_TABLES
        COUNT=$#
    fi

    RANDOM_INDEX=$(( ( $(hexdump -n 2 -e '/2 "%u"' /dev/urandom) % COUNT ) + 1 ))
    eval "NEW_WG=\$$RANDOM_INDEX"

    last_wg="$NEW_WG"
    echo "$NEW_WG"
}

apply_vpn_rules() {
    NEW_WG=$(randomize_wg)

    for SUBNET in $WG_SUBNETS; do
        ip rule add from "$SUBNET" lookup "$NEW_WG" 2>/dev/null

        for HOST in $VPN_BLACKLIST_HOSTS; do
            case "$HOST" in
                "${SUBNET%.*}".*) ip rule add from "$HOST" lookup main 2>/dev/null ;;
            esac
        done
    done

    for HOST in $VPN_WHITELIST_HOSTS $DYNAMIC_WHITELIST_HOSTS; do
        ip rule add from "$HOST" lookup "$NEW_WG" 2>/dev/null
    done

    ip route flush cache
}

remove_vpn_rules() {
    ip rule show | grep -o 'lookup wgc[1-5]' | sed 's/lookup //g' | while read -r RULE; do
        ip rule del lookup "$RULE" 2>/dev/null
    done

    for HOST in $VPN_BLACKLIST_HOSTS; do
        ip rule del from "$HOST" lookup main 2>/dev/null
    done

    ip route flush cache
}

check_status() {
    ACTIVE_VPN=$(get_vpn_routes)

    if [ -z "$ACTIVE_VPN" ]; then
        echo "Active VPN Routes: None"
        curl -sSk --ipv4 --max-time $max_timeout --connect-timeout $connect_timeout "$STATUS_URL"
        curl -sSk --ipv4 --max-time $max_timeout --connect-timeout $connect_timeout "$ORG_URL"
    else
        echo "Active VPN Routes: $ACTIVE_VPN"
        curl -sSk --interface "$ACTIVE_VPN" --ipv4 --max-time $max_timeout --connect-timeout $connect_timeout "$STATUS_URL"
        curl -sSk --interface "$ACTIVE_VPN" --ipv4 --max-time $max_timeout --connect-timeout $connect_timeout "$ORG_URL"
    fi
}

start_vpn() {
    load_dynamic_hosts
    last_wg=$(get_vpn_routes 2>/dev/null)

    remove_vpn_rules
    apply_vpn_rules
    check_status
}

stop_vpn() {
    remove_vpn_rules
    rm -f "$DYNAMIC_HOSTS_FILE"
    check_status
}

toggle_vpn() {
    ACTIVE_VPN=$(get_vpn_routes)

    if [ -z "$ACTIVE_VPN" ]; then
        start_vpn
    else
        stop_vpn
    fi
}

add_dynamic_hosts() {
    for HOST in "$@"; do
        ip rule add from "$HOST" lookup "$(get_vpn_routes)" 2>/dev/null
    done
    DYNAMIC_WHITELIST_HOSTS="$@"
    save_dynamic_hosts
}

if [ "$1" != "start" ] && [ "$1" != "stop" ] && [ "$1" != "restart" ] && [ "$1" != "toggle" ] && [ "$1" != "status" ]; then
    add_dynamic_hosts "$@"
    exit 0
fi

case "$1" in
    status) check_status ;;
    start) start_vpn ;;
    stop) stop_vpn ;;
    restart) start_vpn ;;
    toggle) toggle_vpn ;;
    *) echo "Usage: $0 {start|stop|restart|toggle|status} [dynamic IPs]"; exit 1 ;;
esac