#!/bin/sh
###############################################################################
#                                                                             #
# IPFire.org - A linux based firewall                                         #
# Copyright (C) 2007-2022  IPFire Team  <info@ipfire.org>                     #
# Copyright (C) 2024-2025  BPFire <vincent.mc.li@gmail.com>                     #
#                                                                             #
# This program is free software: you can redistribute it and/or modify        #
# it under the terms of the GNU General Public License as published by        #
# the Free Software Foundation, either version 3 of the License, or           #
# (at your option) any later version.                                         #
#                                                                             #
# This program is distributed in the hope that it will be useful,             #
# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
# GNU General Public License for more details.                                #
#                                                                             #
# You should have received a copy of the GNU General Public License           #
# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
#                                                                             #
###############################################################################

. /etc/sysconfig/rc
. $rc_functions

eval $(/usr/local/bin/readhash /var/ipfire/ddos/tcp-ddos-settings)

MSSOPTS="--mss4 1460 --mss6 1440"
TTLOPTS="--ttl 64"
WSCALE="--wscale 0"
BPF_OBJECT_FILE="/usr/lib/bpf/xdp_synproxy.bpf.o"
PROG_NAME="syncookie_xdp"
MAP_PIN_PATH="/sys/fs/bpf/xdp-ddos/ddos_progs"
KEY=0

get_ports () {
# Define an empty variable to store the output
	local output=""
	local ddos_port_file="$1"

# Read the input file line by line
	while IFS= read -r line; do
		# Check if the line contains '=on'
		if [[ "$line" == [0-9]*"=on" ]]; then
			# Extract the service/port number
			service=$(echo "$line" | cut -d'=' -f1)
			# Append the service/port number to the output string
			output="$output$service,"
		fi
	done < $ddos_port_file

	# Remove the trailing comma from the output string
	output="${output%,}"
	echo $output
}

load_syncookie () {
	sysctl -w net.ipv4.tcp_syncookies=1
	sysctl -w net.ipv4.tcp_timestamps=1
	sysctl -w net.netfilter.nf_conntrack_tcp_loose=0
	/usr/sbin/xdp_ddos add $BPF_OBJECT_FILE $PROG_NAME $MAP_PIN_PATH $KEY
	if [ $? -eq 0 ]; then
		prog_id=$(bpftool prog | grep syncookie_xdp | awk '{print $1}' | cut -d':' -f1)
		xdp_synproxy --prog $prog_id $MSSOPTS $WSCALE $TTLOPTS --ports="$tcp_ports"
	else
		boot_mesg "Error to load $BPF_OBJECT_FILE"
	fi
}

unload_syncookie () {
	sysctl -w net.ipv4.tcp_syncookies=1
	/usr/sbin/xdp_ddos del $MAP_PIN_PATH $KEY
	if [ $? -eq 0 ]; then
		boot_mesg "syncookie_xdp unloaded!"
	else
		boot_mesg "Error syncookie_xdp not unloaded!"
	fi
}

tcp_ports="$(get_ports /var/ipfire/ddos/tcp-ddos-settings)"

case "$1" in
	start)
		if [ ! -e /var/ipfire/red/active ]; then
			boot_mesg " ERROR! Red0 interface not online!"
			echo_warning
			exit 1
		fi
		boot_mesg -n "Starting tcp ddos..."
		if [ "$ENABLE_TCP_DDOS" == "on" ]; then
			load_syncookie
		fi
		;;

	stop)
		boot_mesg "Stopping tcp ddos..."
		if [ "$ENABLE_TCP_DDOS" == "off" ]; then
			unload_syncookie
		fi
		;;

	restart)
		$0 stop
		sleep 1
		$0 start
		;;

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