#!/bin/bash

PORT=25565
MAX_CONNECTIONS=3
BAN_LIST="/etc/iptables/banned_ips"

iptables -N BAN_DDOS 2>/dev/null
iptables -F BAN_DDOS
iptables -A BAN_DDOS -j DROP

check_connections() {
    # Получаем список IP с количеством соединений к порту 25565
    connections=$(ss -tn state established "( sport = :$PORT or dport = :$PORT )" | awk '{print $4}' | grep -oE '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' | sort | uniq -c | awk '$1 > '$MAX_CONNECTIONS' {print $2}')

    for ip in $connections; do
        # Проверяем, не забанен ли IP уже
        if ! grep -q "$ip" "$BAN_LIST" 2>/dev/null; then
            echo "Бан IP: $ip за превышение $MAX_CONNECTIONS соединений"
            iptables -A BAN_DDOS -s "$ip" -j DROP
            echo "$ip" >> "$BAN_LIST"
        fi
    done
}

iptables -F INPUT
iptables -P INPUT ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A INPUT -p tcp --dport $PORT -m connlimit --connlimit-above $MAX_CONNECTIONS -j BAN_DDOS
iptables -A INPUT -p tcp --dport $PORT -j ACCEPT

check_connections

iptables-save > /etc/iptables/rules.v4