#!/bin/bash
# Зеркало RADIUS accounting (udp/1813) между 10.16.20.226 <-> 10.16.20.231 в GRETAP на 10.16.20.225
set -e

IF=ens18
LOCAL=10.16.20.226
REMOTE=10.16.20.225
PEER=10.16.20.231
TUN=gre-mirror

start() {
  modprobe ip_gre; modprobe cls_flower; modprobe act_mirred

  ip link add $TUN type gretap local $LOCAL remote $REMOTE ttl 64
  ip link set $TUN up

  tc qdisc add dev $IF clsact

  # Входящие от 231 (запросы на 1813 или ответы с 1813)
  tc filter add dev $IF ingress protocol ip prio 1 flower ip_proto udp src_ip $PEER dst_port 1813 \
     action mirred egress mirror dev $TUN
  tc filter add dev $IF ingress protocol ip prio 2 flower ip_proto udp src_ip $PEER src_port 1813 \
     action mirred egress mirror dev $TUN

  # Исходящие на 231
  tc filter add dev $IF egress protocol ip prio 1 flower ip_proto udp dst_ip $PEER dst_port 1813 \
     action mirred egress mirror dev $TUN
  tc filter add dev $IF egress protocol ip prio 2 flower ip_proto udp dst_ip $PEER src_port 1813 \
     action mirred egress mirror dev $TUN
}

stop() {
  tc qdisc del dev $IF clsact 2>/dev/null || true
  ip link del $TUN 2>/dev/null || true
}

case "$1" in
  start) start ;;
  stop)  stop ;;
  restart) stop; start ;;
  *) echo "Usage: $0 {start|stop|restart}"; exit 1 ;;
esac