Rotate Wireguard ports

wgporo.sh

#!/bin/sh
set -u

WGIF="winnie"
STEP=3600
PSTART=5500
PEND=5999

CONFFILE="/etc/wireguard/$WGIF.conf"
PLEN=$((PEND-PSTART+1))

timestamp=$(date +%s)
slot=$(((timestamp/STEP)*101))
port=$((slot%PLEN+PSTART))

ifstatus=$(wg show $WGIF 2> /dev/null)
if [ $? -ne 0 ]; then
    echo "$WGIF not up, exiting"
    exit
fi

activeport=$(echo $ifstatus | grep "endpoint:" | cut -d':' -f3)
if [ "$activeport" -eq "$port" ]; then
    echo "Port unchanged, exiting"
    exit
fi

echo "Rotating port for $WGIF: from $activeport to $port"
sed -i "s_\(Endpoint.\+:\)[[:digit:]]\+_\1${port}_" $CONFFILE
wg-quick down $WGIF > /dev/null 2>&1 && wg-quick up $WGIF > /dev/null 2>&1
if [ $? -eq 0 ]; then
    echo "Done"
else
    echo "Failed to bring up interface"
fi