#!/bin/sh
# shellcheck disable=SC2059

# minifirewall is a shell script for easy firewalling on a standalone server
# It uses netfilter/iptables http://netfilter.org/ designed for recent Linux kernel
# See https://gitea.evolix.org/evolix/minifirewall

# Copyright (c) 2007-2022 Evolix
# 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.

# Description
# script for standalone server

# Start or stop minifirewall
#

### BEGIN INIT INFO
# Provides:          minifirewall
# Required-Start:
# Required-Stop:
# Should-Start:      $network $syslog $named
# Should-Stop:       $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: start and stop the firewall
# Description:       Firewall designed for standalone server
### END INIT INFO

VERSION="22.06"

NAME="minifirewall"
# shellcheck disable=SC2034
DESC="Firewall designed for standalone server"

set -u

# Variables configuration
#########################

config_file="/etc/default/minifirewall"
includes_dir="/etc/minifirewall.d"

# iptables paths
IPT=$(command -v iptables)
if [ -z "${IPT}" ]; then
    echo "Unable to find 'iptables\` command in PATH." >&2
    exit 1
fi
IPT6=$(command -v ip6tables)
if [ -z "${IPT6}" ]; then
    echo "Unable to find 'ip6tables\` command in PATH." >&2
    exit 1
fi

# TCP/IP variables
LOOPBACK='127.0.0.0/8'
CLASSA='10.0.0.0/8'
CLASSB='172.16.0.0/12'
CLASSC='192.168.0.0/16'
CLASSD='224.0.0.0/4'
CLASSE='240.0.0.0/5'
ALL='0.0.0.0'
BROAD='255.255.255.255'
PORTSROOT='0:1023'
PORTSUSER='1024:65535'

# Configuration

INT=''
IPV6=''
DOCKER=''
INTLAN=''
TRUSTEDIPS=''
PRIVILEGIEDIPS=''
SERVICESTCP1p=''
SERVICESUDP1p=''
SERVICESTCP1=''
SERVICESUDP1=''
SERVICESTCP2=''
SERVICESUDP2=''
SERVICESTCP3=''
SERVICESUDP3=''
DNSSERVEURS=''
HTTPSITES=''
HTTPSSITES=''
FTPSITES=''
SSHOK=''
SMTPOK=''
SMTPSECUREOK=''
NTPOK=''
PROXY=''
PROXYBYPASS=''
PROXYPORT=''
BACKUPSERVERS=''

LEGACY_CONFIG='off'

STATE_FILE_LATEST='/var/run/minifirewall_state_latest'
STATE_FILE_CURRENT='/var/run/minifirewall_state_current'
STATE_FILE_PREVIOUS='/var/run/minifirewall_state_previous'
STATE_FILE_DIFF='/var/run/minifirewall_state_diff'

LOGGER_BIN=$(command -v logger)

# No colors by default
RED=''
GREEN=''
YELLOW=''
BLUE=''
MAGENTA=''
CYAN=''
WHITE=''
BOLD=''
RESET=''
# check if stdout is a terminal...
if [ -t 1 ]; then

    # see if it supports colors...
    ncolors=$(tput colors)

    # shellcheck disable=SC2086
    if [ -n "${ncolors}" ] && [ ${ncolors} -ge 8 ]; then
        RED=$(tput setaf 1)
        GREEN=$(tput setaf 2)
        YELLOW=$(tput setaf 3)
        BLUE=$(tput setaf 4)
        MAGENTA=$(tput setaf 5)
        CYAN=$(tput setaf 6)
        WHITE=$(tput setaf 7)
        BOLD=$(tput bold)
        RESET='\e[m'
    fi
fi

## pseudo dry-run :
## Uncomment and call these functions instead of the real iptables and ip6tables commands
# IPT="fake_iptables"
# IPT6="fake_ip6tables"
# fake_iptables() {
#     printf "DRY-RUN iptables %s\n" "$*"
# }
# fake_ip6tables() {
#     printf "DRY-RUN ip6tables %s\n" "$*"
# }
## Beware that commands executed from included files are not modified by this trick.

syslog_info() {
    if [ -x "${LOGGER_BIN}" ]; then
        ${LOGGER_BIN} -t "${NAME}" -p daemon.info "$1"
    fi
}
syslog_error() {
    if [ -x "${LOGGER_BIN}" ]; then
        ${LOGGER_BIN} -t "${NAME}" -p daemon.error "$1"
    fi
}
sort_values() {
    echo "$*" | tr ' ' '\n' | sort -h
}
is_ipv6_enabled() {
    test "${IPV6}" != "off"
}
is_docker_enabled() {
    test "${DOCKER}" = "on"
}
is_proxy_enabled() {
    test "${PROXY}" = "on"
}
is_ipv6() {
    echo "$1" | grep -q ':' 
}
is_legacy_config() {
    test "${LEGACY_CONFIG}" != "off"
}
chain_exists() {
    chain_name="$1"
    if [ $# -ge 2 ]; then
        intable="--table $2"
    else
        intable=""
    fi
    # shellcheck disable=SC2086
    iptables ${intable} -nL "${chain_name}" >/dev/null 2>&1
}
source_file_or_error() {
    file=$1
    syslog_info "sourcing \`${file}'"
    printf "${BLUE}sourcing \`%s'${RESET}\n" "${file}"

    tmpfile=$(mktemp --tmpdir=/tmp minifirewall.XXX)
    . "${file}" 2>"${tmpfile}" >&2

    if [ -s "${tmpfile}" ]; then
            syslog_error "Error while sourcing ${file}"
            printf "${RED}%s returns standard or error output (see below). Stopping.${RESET}\n" ${file} >&2
            cat "${tmpfile}"
            exit 1
    fi
    rm -f "${tmpfile}"
}
source_configuration() {
    if ! test -f ${config_file}; then
        printf "${RED}%s does not exist${RESET}\n" "${config_file}" >&2

        ## We still want to deal with this really old configuration file
        ## even if it has been deprecated since Debian 8
        old_config_file="/etc/firewall.rc"
        if test -f ${old_config_file}; then
            printf "${YELLOW}%s is deprecated and ignored. Rename it to %s${RESET}\n" "${old_config_file}" "${config_file}" >&2
        fi

        exit 1
    fi

    # If we find something other than a blank line, a comment or a variable assignment
    if grep --quiet --extended-regexp --invert-match "^\s*(#|$|\w+=)" "${config_file}"; then
        # Backward compatible mode
        ###########################

        printf "${YELLOW}legacy config detected${RESET}\n"
        LEGACY_CONFIG='on'

        # Non-backward compatible mode
        ###############################

        # If we ever want to remove the backward compatible mode
        # we can remove the two lines above and uncomment the lines below.
        # They break if any iptables/ip6tables command is found in the configuration file

        # echo "iptables/ip6tables commands found in ${config_file}." >&2
        # echo "Move them in included files (in ${includes_dir})." >&2
        # exit 1
    fi

    if is_legacy_config; then
        # In this mode, we extract all variable definitions
        # to a temporary file that we can source.
        # It allow iptables/ip6tables commands to remain in the configuration file
        # and not interfere with the configuration step.

        tmp_config_file=$(mktemp --tmpdir=/tmp minifirewall.XXX)
        # get only variable assignments
        grep -E "^\s*\w+=" "${config_file}" > "${tmp_config_file}"

        source_file_or_error "${tmp_config_file}"
        rm -f "${tmp_config_file}"
    else
        source_file_or_error "${config_file}"
    fi
}
source_includes() {
    if [ -d "${includes_dir}" ]; then
        include_files=$(find ${includes_dir} -type f -readable -not -name '*.*' | sort -h)
        for include_file in ${include_files}; do
            source_file_or_error "${include_file}"
        done
    fi
}
check_unpersisted_state() {
    cmp_bin=$(command -v cmp)
    diff_bin=$(command -v diff)

    if [ -z "${cmp_bin}" ]; then
        printf "${YELLOW}skip state comparison (Can't find cmp command)${RESET}\n" >&2
    elif [ -z "${diff_bin}" ]; then
        printf "${YELLOW}skip state comparison (Can't find diff command)${RESET}\n" >&2
    else
        # store current state
        mkdir -p "$(dirname "${STATE_FILE_CURRENT}")"
        status_without_numbers > "${STATE_FILE_CURRENT}"

        # clean previous diff file
        rm -f "${STATE_FILE_DIFF}"

        if [ -f "${STATE_FILE_LATEST}" ]; then
            cmp_result=$(cmp "${STATE_FILE_LATEST}" "${STATE_FILE_CURRENT}")
            cmp_rc=$?

            if [ ${cmp_rc} -eq 0 ]; then
                # echo "   rules have not changed since latest start"
                :
            elif [ ${cmp_rc} -eq 1 ]; then
                diff -u "${STATE_FILE_LATEST}" "${STATE_FILE_CURRENT}" > "${STATE_FILE_DIFF}"
                printf "${YELLOW}WARNING: current state is different than persisted state, check %s${RESET}\n" "${STATE_FILE_DIFF}" >&2
            else
                printf "${RED}ERROR comparing rules:${RESET}\n" >&2
                echo "${cmp_result}" >&2
            fi
        fi
        # cleanup
        rm -f "${STATE_FILE_CURRENT}"
    fi
}
report_state_changes() {
    cmp_bin=$(command -v cmp)
    diff_bin=$(command -v diff)

    if [ -z "${cmp_bin}" ]; then
        printf "${YELLOW}skip state comparison (Can't find cmp command)${RESET}\n" >&2
        return
    elif [ -z "${diff_bin}" ]; then
        printf "${YELLOW}skip state comparison (Can't find diff command)${RESET}\n" >&2
    else
        # If there is a known state
        # let's compare it with the current state
        if [ -f "${STATE_FILE_LATEST}" ]; then
            check_unpersisted_state
        fi

        # Then reset the known state
        mkdir -p "$(dirname "${STATE_FILE_LATEST}")"
        status_without_numbers > "${STATE_FILE_LATEST}"

        # But if there is a previous known state
        # let's compare with the new known state
        if [ -f "${STATE_FILE_PREVIOUS}" ]; then
            cmp_result=$(cmp "${STATE_FILE_PREVIOUS}" "${STATE_FILE_LATEST}")
            cmp_rc=$?

            if [ ${cmp_rc} -eq 0 ]; then
                # echo "Rules have not changed since previous start"
                :
            elif [ ${cmp_rc} -eq 1 ]; then
                diff -u "${STATE_FILE_PREVIOUS}" "${STATE_FILE_LATEST}" > "${STATE_FILE_DIFF}"
                printf "${YELLOW}INFO: rules have changed since latest start, check %s${RESET}\n" "${STATE_FILE_DIFF}" >&2
            else
                printf "${RED}ERROR comparing rules:${RESET}\n" >&2
                echo "${cmp_result}" >&2
            fi
        fi
    fi
}

start() {
    syslog_info "starting"
    printf "${BOLD}${NAME} starting${RESET}\n"

    # Stop and warn if error!
    set -e
    trap 'printf "${RED}${NAME} failed : an error occured during startup.${RESET}\n"; syslog_error "failed" ' INT TERM EXIT

    # sysctl network security settings
    ##################################

    # Set 1 to ignore broadcast pings (default)
    : "${SYSCTL_ICMP_ECHO_IGNORE_BROADCASTS:=1}"
    # Set 1 to ignore bogus ICMP responses (default)
    : "${SYSCTL_ICMP_IGNORE_BOGUS_ERROR_RESPONSES:=1}"
    # Set 0 to disable source routing (default)
    : "${SYSCTL_ACCEPT_SOURCE_ROUTE:=0}"
    # Set 1 to enable TCP SYN cookies (default)
    # cf http://cr.yp.to/syncookies.html
    : "${SYSCTL_TCP_SYNCOOKIES:=1}"
    # Set 0 to disable ICMP redirects (default)
    : "${SYSCTL_ICMP_REDIRECTS:=0}"
    # Set 1 to enable Reverse Path filtering (default)
    # Set 0 if VRRP is used
    : "${SYSCTL_RP_FILTER:=1}"
    # Set 1 to log packets with inconsistent address (default)
    : "${SYSCTL_LOG_MARTIANS:=1}"

    if [ "${SYSCTL_ICMP_ECHO_IGNORE_BROADCASTS}" = "1" ] || [ "${SYSCTL_ICMP_ECHO_IGNORE_BROADCASTS}" = "0" ]; then
        echo "${SYSCTL_ICMP_ECHO_IGNORE_BROADCASTS}" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
        # Apparently not applicable to IPv6
    else
        printf "${RED}ERROR: invalid %s value '%s', must be '0' or '1'.\n" "SYSCTL_ICMP_ECHO_IGNORE_BROADCASTS" "${SYSCTL_ICMP_ECHO_IGNORE_BROADCASTS}" >&2
        exit 1
    fi

    if [ "${SYSCTL_ICMP_IGNORE_BOGUS_ERROR_RESPONSES}" = "1" ] || [ "${SYSCTL_ICMP_IGNORE_BOGUS_ERROR_RESPONSES}" = "0" ]; then
        echo "${SYSCTL_ICMP_IGNORE_BOGUS_ERROR_RESPONSES}" > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses
        # Apparently not applicable to IPv6
    else
        printf "${RED}ERROR: invalid %s value '%s', must be '0' or '1'.\n" "SYSCTL_ICMP_IGNORE_BOGUS_ERROR_RESPONSES" "${SYSCTL_ICMP_IGNORE_BOGUS_ERROR_RESPONSES}" >&2
        exit 1
    fi

    if [ "${SYSCTL_ACCEPT_SOURCE_ROUTE}" = "1" ] || [ "${SYSCTL_ACCEPT_SOURCE_ROUTE}" = "0" ]; then
        for proc_sys_file in /proc/sys/net/ipv4/conf/*/accept_source_route; do
            echo "${SYSCTL_ACCEPT_SOURCE_ROUTE}" > "${proc_sys_file}"
        done
        if is_ipv6_enabled; then
            for proc_sys_file in /proc/sys/net/ipv6/conf/*/accept_source_route; do
                echo "${SYSCTL_ACCEPT_SOURCE_ROUTE}" > "${proc_sys_file}"
            done
        fi
    else
        printf "${RED}ERROR: invalid %s value '%s', must be '0' or '1'.\n" "SYSCTL_ACCEPT_SOURCE_ROUTE" "${SYSCTL_ACCEPT_SOURCE_ROUTE}" >&2
        exit 1
    fi

    if [ "${SYSCTL_TCP_SYNCOOKIES}" = "1" ] || [ "${SYSCTL_TCP_SYNCOOKIES}" = "0" ]; then
        echo "${SYSCTL_TCP_SYNCOOKIES}" > /proc/sys/net/ipv4/tcp_syncookies
        # Apparently not applicable to IPv6
    else
        printf "${RED}ERROR: invalid %s value '%s', must be '0' or '1'.\n" "SYSCTL_TCP_SYNCOOKIES" "${SYSCTL_TCP_SYNCOOKIES}" >&2
        exit 1
    fi

    if [ "${SYSCTL_ICMP_REDIRECTS}" = "1" ] || [ "${SYSCTL_ICMP_REDIRECTS}" = "0" ]; then
        for proc_sys_file in /proc/sys/net/ipv4/conf/*/accept_redirects; do
            echo "${SYSCTL_ICMP_REDIRECTS}" > "${proc_sys_file}"
        done
        for proc_sys_file in /proc/sys/net/ipv4/conf/*/send_redirects; do
            echo "${SYSCTL_ICMP_REDIRECTS}" > "${proc_sys_file}"
        done
        if is_ipv6_enabled; then
            for proc_sys_file in /proc/sys/net/ipv6/conf/*/accept_redirects; do
                echo "${SYSCTL_ICMP_REDIRECTS}" > "${proc_sys_file}"
            done
        fi
    else
        printf "${RED}ERROR: invalid %s value '%s', must be '0' or '1'.\n" "SYSCTL_ICMP_REDIRECTS" "${SYSCTL_ICMP_REDIRECTS}" >&2
        exit 1
    fi

    if [ "${SYSCTL_RP_FILTER}" = "1" ] || [ "${SYSCTL_RP_FILTER}" = "0" ]; then
        for proc_sys_file in /proc/sys/net/ipv4/conf/*/rp_filter; do
            echo "${SYSCTL_RP_FILTER}" > "${proc_sys_file}"
        done
        # Apparently not applicable to IPv6
    else
        printf "${RED}ERROR: invalid %s value '%s', must be '0' or '1'.\n" "SYSCTL_RP_FILTER" "${SYSCTL_RP_FILTER}" >&2
        exit 1
    fi

    if [ "${SYSCTL_LOG_MARTIANS}" = "1" ] || [ "${SYSCTL_LOG_MARTIANS}" = "0" ]; then
        for proc_sys_file in /proc/sys/net/ipv4/conf/*/log_martians; do
            echo "${SYSCTL_LOG_MARTIANS}" > "${proc_sys_file}"
        done
        # Apparently not applicable to IPv6
    else
        printf "${RED}ERROR: invalid %s value '%s', must be '0' or '1'.\n" "SYSCTL_LOG_MARTIANS" "${SYSCTL_LOG_MARTIANS}" >&2
        exit 1
    fi

    # IPTables configuration
    ########################

    ${IPT} -N LOG_DROP
    ${IPT} -A LOG_DROP -j LOG  --log-prefix '[IPTABLES DROP] : '
    ${IPT} -A LOG_DROP -j DROP
    ${IPT} -N LOG_ACCEPT
    ${IPT} -A LOG_ACCEPT -j LOG  --log-prefix '[IPTABLES ACCEPT] : '
    ${IPT} -A LOG_ACCEPT -j ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -N LOG_DROP
        ${IPT6} -A LOG_DROP -j LOG  --log-prefix '[IPTABLES DROP] : '
        ${IPT6} -A LOG_DROP -j DROP
        ${IPT6} -N LOG_ACCEPT
        ${IPT6} -A LOG_ACCEPT -j LOG  --log-prefix '[IPTABLES ACCEPT] : '
        ${IPT6} -A LOG_ACCEPT -j ACCEPT
    fi

    # Source additional rules and commands
    # * from legacy configuration file (/etc/default/minifirewall)
    # * from configuration directory (/etc/minifirewall.d/*)
    source_includes

    # IP/ports lists are sorted to have consistent ordering
    # You can disable this feature by simply commenting the following lines
    LOOPBACK=$(sort_values ${LOOPBACK})
    INTLAN=$(sort_values ${INTLAN})
    TRUSTEDIPS=$(sort_values ${TRUSTEDIPS})
    PRIVILEGIEDIPS=$(sort_values ${PRIVILEGIEDIPS})
    SERVICESTCP1p=$(sort_values ${SERVICESTCP1p})
    SERVICESUDP1p=$(sort_values ${SERVICESUDP1p})
    SERVICESTCP1=$(sort_values ${SERVICESTCP1})
    SERVICESUDP1=$(sort_values ${SERVICESUDP1})
    SERVICESTCP2=$(sort_values ${SERVICESTCP2})
    SERVICESUDP2=$(sort_values ${SERVICESUDP2})
    SERVICESTCP3=$(sort_values ${SERVICESTCP3})
    SERVICESUDP3=$(sort_values ${SERVICESUDP3})
    DNSSERVEURS=$(sort_values ${DNSSERVEURS})
    HTTPSITES=$(sort_values ${HTTPSITES})
    HTTPSSITES=$(sort_values ${HTTPSSITES})
    FTPSITES=$(sort_values ${FTPSITES})
    SSHOK=$(sort_values ${SSHOK})
    SMTPOK=$(sort_values ${SMTPOK})
    SMTPSECUREOK=$(sort_values ${SMTPSECUREOK})
    NTPOK=$(sort_values ${NTPOK})
    PROXYBYPASS=$(sort_values ${PROXYBYPASS})
    BACKUPSERVERS=$(sort_values ${BACKUPSERVERS})

    # Trusted ip addresses
    ${IPT} -N ONLYTRUSTED
    ${IPT} -A ONLYTRUSTED -j LOG_DROP
    if is_ipv6_enabled; then
        ${IPT6} -N ONLYTRUSTED
        ${IPT6} -A ONLYTRUSTED -j LOG_DROP
    fi
    for ip in ${TRUSTEDIPS}; do
        if is_ipv6 ${ip}; then
            if is_ipv6_enabled; then
                ${IPT6} -I ONLYTRUSTED -s ${ip} -j ACCEPT
            fi
        else
            ${IPT} -I ONLYTRUSTED -s ${ip} -j ACCEPT
        fi
    done

    # Privilegied ip addresses
    # (trusted ip addresses *are* privilegied)
    ${IPT} -N ONLYPRIVILEGIED
    ${IPT} -A ONLYPRIVILEGIED -j ONLYTRUSTED
    if is_ipv6_enabled; then
        ${IPT6} -N ONLYPRIVILEGIED
        ${IPT6} -A ONLYPRIVILEGIED -j ONLYTRUSTED
    fi
    for ip in ${PRIVILEGIEDIPS}; do
        if is_ipv6 ${ip}; then
            if is_ipv6_enabled; then
                ${IPT6} -I ONLYPRIVILEGIED -s ${ip} -j ACCEPT
            fi
        else
            ${IPT} -I ONLYPRIVILEGIED -s ${ip} -j ACCEPT
        fi
    done

    # Chain for restrictions (blacklist IPs/ranges)
    ${IPT} -N NEEDRESTRICT
    if is_ipv6_enabled; then
        ${IPT6} -N NEEDRESTRICT
    fi

    # We allow all on loopback interface
    ${IPT} -A INPUT -i lo -j ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -A INPUT -i lo -j ACCEPT
    fi
    # if OUTPUTDROP
    ${IPT} -A OUTPUT -o lo -j ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -A OUTPUT -o lo -j ACCEPT
    fi

    # We avoid "martians" packets, typical when W32/Blaster virus
    # attacked windowsupdate.com and DNS was changed to 127.0.0.1
    # ${IPT} -t NAT -I PREROUTING -s ${LOOPBACK} -i ! lo -j DROP
    for IP in ${LOOPBACK}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -s ${IP} ! -i lo -j DROP
            fi
        else
            ${IPT} -A INPUT -s ${IP} ! -i lo -j DROP
        fi
    done

    if is_docker_enabled; then
        # WARN: IPv6 not yet supported for Docker rules
        ${IPT} -N MINIFW-DOCKER-TRUSTED
        ${IPT} -A MINIFW-DOCKER-TRUSTED -j DROP

        ${IPT} -N MINIFW-DOCKER-PRIVILEGED
        ${IPT} -A MINIFW-DOCKER-PRIVILEGED -j MINIFW-DOCKER-TRUSTED
        ${IPT} -A MINIFW-DOCKER-PRIVILEGED -j RETURN

        ${IPT} -N MINIFW-DOCKER-PUB
        ${IPT} -A MINIFW-DOCKER-PUB -j MINIFW-DOCKER-PRIVILEGED
        ${IPT} -A MINIFW-DOCKER-PUB -j RETURN

        # Flush DOCKER-USER if exist, create it if absent
        if chain_exists 'DOCKER-USER'; then
            ${IPT} -F DOCKER-USER
        else
            ${IPT} -N DOCKER-USER
        fi;

        # Pipe new connection through MINIFW-DOCKER-PUB
        ${IPT} -A DOCKER-USER -i ${INT} -m state  --state NEW -j MINIFW-DOCKER-PUB
        ${IPT} -A DOCKER-USER -j RETURN
    fi


    # Local services restrictions
    #############################

    # Allow services for ${INTLAN} (local server or local network)
    for IP in ${INTLAN}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -s ${IP} -j ACCEPT
            fi
        else
            ${IPT} -A INPUT -s ${IP} -j ACCEPT
        fi
    done

    # Enable protection chain for sensible services
    for port in ${SERVICESTCP1p}; do
        ${IPT} -A INPUT -p tcp --dport ${port} -j NEEDRESTRICT
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p tcp --dport ${port} -j NEEDRESTRICT
        fi
    done

    for port in ${SERVICESUDP1p}; do
        ${IPT} -A INPUT -p udp --dport ${port} -j NEEDRESTRICT
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p udp --dport ${port} -j NEEDRESTRICT
        fi
    done

    # Public service
    for port in ${SERVICESTCP1}; do
        ${IPT} -A INPUT -p tcp --dport ${port} -j ACCEPT
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p tcp --dport ${port} -j ACCEPT
        fi
    done

    for port in ${SERVICESUDP1}; do
        ${IPT} -A INPUT -p udp --dport ${port} -j ACCEPT
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p udp --dport ${port} -j ACCEPT
        fi
    done

    # Privilegied services
    for port in ${SERVICESTCP2}; do
        ${IPT} -A INPUT -p tcp --dport ${port} -j ONLYPRIVILEGIED
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p tcp --dport ${port} -j ONLYPRIVILEGIED
        fi
    done

    for port in ${SERVICESUDP2}; do
        ${IPT} -A INPUT -p udp --dport ${port} -j ONLYPRIVILEGIED
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p udp --dport ${port} -j ONLYPRIVILEGIED
        fi
    done

    # Private services
    for port in ${SERVICESTCP3}; do
        ${IPT} -A INPUT -p tcp --dport ${port} -j ONLYTRUSTED
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p tcp --dport ${port} -j ONLYTRUSTED
        fi
    done

    for port in ${SERVICESUDP3}; do
        ${IPT} -A INPUT -p udp --dport ${port} -j ONLYTRUSTED
        if is_ipv6_enabled; then
            ${IPT6} -A INPUT -p udp --dport ${port} -j ONLYTRUSTED
        fi
    done


    if is_docker_enabled; then
        # WARN: IPv6 not yet supported

        # Public services defined in SERVICESTCP1 & SERVICESUDP1
        for dstport in ${SERVICESTCP1}; do
            ${IPT} -I MINIFW-DOCKER-PUB -p tcp --dport "${dstport}" -j RETURN
        done

        for dstport in ${SERVICESUDP1}; do
            ${IPT} -I MINIFW-DOCKER-PUB -p udp --dport "${dstport}" -j RETURN
        done

        # Privileged services (accessible from privileged & trusted IPs)
        for dstport in ${SERVICESTCP2}; do
            for srcip in ${PRIVILEGIEDIPS}; do
                if ! is_ipv6 ${srcip}; then
                    ${IPT} -I MINIFW-DOCKER-PRIVILEGED -p tcp -s "${srcip}" --dport "${dstport}" -j RETURN
                fi
            done

            for srcip in ${TRUSTEDIPS}; do
                if ! is_ipv6 ${srcip}; then
                    ${IPT} -I MINIFW-DOCKER-PRIVILEGED -p tcp -s "${srcip}" --dport "${dstport}" -j RETURN
                fi
            done
        done

        for dstport in ${SERVICESUDP2}; do
            for srcip in ${PRIVILEGIEDIPS}; do
                if ! is_ipv6 ${srcip}; then
                    ${IPT} -I MINIFW-DOCKER-PRIVILEGED -p udp -s "${srcip}" --dport "${dstport}" -j RETURN
                fi
            done

            for srcip in ${TRUSTEDIPS}; do
                if ! is_ipv6 ${srcip}; then
                    ${IPT} -I MINIFW-DOCKER-PRIVILEGED -p udp -s "${srcip}" --dport "${dstport}" -j RETURN
                fi
            done
        done

        # Trusted services (accessible from trusted IPs)
        for dstport in ${SERVICESTCP3}; do
            for srcip in ${TRUSTEDIPS}; do
                if ! is_ipv6 ${srcip}; then
                    ${IPT} -I MINIFW-DOCKER-TRUSTED -p tcp -s "${srcip}" --dport "${dstport}" -j RETURN
                fi
            done
        done

        for dstport in ${SERVICESUDP3}; do
            for srcip in ${TRUSTEDIPS}; do
                if ! is_ipv6 ${srcip}; then
                    ${IPT} -I MINIFW-DOCKER-TRUSTED -p udp -s "${srcip}" --dport "${dstport}" -j RETURN
                fi
            done
        done
    fi

    # External services
    ###################

    # DNS authorizations
    for IP in ${DNSSERVEURS}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -p tcp ! --syn --sport 53 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
                ${IPT6} -A INPUT -p udp --sport 53 --dport ${PORTSUSER} -s ${IP} -m state --state ESTABLISHED,RELATED -j ACCEPT
                ${IPT6} -A OUTPUT -o ${INT} -p udp -d ${IP} --dport 53 --match state --state NEW -j ACCEPT
            fi
        else 
            ${IPT} -A INPUT -p tcp ! --syn --sport 53 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            ${IPT} -A INPUT -p udp --sport 53 --dport ${PORTSUSER} -s ${IP} -m state --state ESTABLISHED,RELATED -j ACCEPT
            ${IPT} -A OUTPUT -o ${INT} -p udp -d ${IP} --dport 53 --match state --state NEW -j ACCEPT
        fi
    done

    # HTTP (TCP/80) authorizations
    for IP in ${HTTPSITES}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -p tcp ! --syn --sport 80 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            fi
        else 
            ${IPT} -A INPUT -p tcp ! --syn --sport 80 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
        fi
    done

    # HTTPS (TCP/443) authorizations
    for IP in ${HTTPSSITES}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -p tcp ! --syn --sport 443 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            fi
        else 
            ${IPT} -A INPUT -p tcp ! --syn --sport 443 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
        fi
    done

    # FTP (so complex protocol...) authorizations
    for IP in ${FTPSITES}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                # requests on Control connection
                ${IPT6} -A INPUT -p tcp ! --syn --sport 21 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
                # FTP port-mode on Data Connection
                ${IPT6} -A INPUT -p tcp --sport 20 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
                # FTP passive-mode on Data Connection
                # WARNING, this allow all connections on TCP ports > 1024
                ${IPT6} -A INPUT -p tcp ! --syn --sport ${PORTSUSER} --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            fi
        else 
            # requests on Control connection
            ${IPT} -A INPUT -p tcp ! --syn --sport 21 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            # FTP port-mode on Data Connection
            ${IPT} -A INPUT -p tcp --sport 20 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            # FTP passive-mode on Data Connection
            # WARNING, this allow all connections on TCP ports > 1024
            ${IPT} -A INPUT -p tcp ! --syn --sport ${PORTSUSER} --dport ${PORTSUSER} -s ${IP} -j ACCEPT
        fi
    done

    # SSH authorizations
    for IP in ${SSHOK}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -p tcp ! --syn --sport 22 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            fi
        else 
            ${IPT} -A INPUT -p tcp ! --syn --sport 22 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
        fi
    done

    # SMTP authorizations
    for IP in ${SMTPOK}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -p tcp ! --syn --sport 25 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            fi
        else 
            ${IPT} -A INPUT -p tcp ! --syn --sport 25 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
        fi
    done

    # secure SMTP (TCP/465 et TCP/587) authorizations
    for IP in ${SMTPSECUREOK}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -p tcp ! --syn --sport 465 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
                ${IPT6} -A INPUT -p tcp ! --syn --sport 587 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            fi
        else 
            ${IPT} -A INPUT -p tcp ! --syn --sport 465 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
            ${IPT} -A INPUT -p tcp ! --syn --sport 587 --dport ${PORTSUSER} -s ${IP} -j ACCEPT
        fi
    done

    # NTP authorizations
    for IP in ${NTPOK}; do
        if is_ipv6 ${IP}; then
            if is_ipv6_enabled; then
                ${IPT6} -A INPUT -p udp --sport 123 -s ${IP} -j ACCEPT
                ${IPT6} -A OUTPUT -o ${INT} -p udp -d ${IP} --dport 123 --match state --state NEW -j ACCEPT
            fi
        else 
            ${IPT} -A INPUT -p udp --sport 123 -s ${IP} -j ACCEPT
            ${IPT} -A OUTPUT -o ${INT} -p udp -d ${IP} --dport 123 --match state --state NEW -j ACCEPT
        fi
    done

    # Proxy (Squid)
    if is_proxy_enabled; then
        # WARN: Squid only listen on IPv4 yet
        # TODO: verify that the pattern used for IPv4 is relevant with IPv6

        ${IPT} -t nat -A OUTPUT -p tcp --dport 80 -m owner --uid-owner proxy -j ACCEPT
        for dstip in ${PROXYBYPASS}; do
            if ! is_ipv6 ${dstip}; then
                ${IPT} -t nat -A OUTPUT -p tcp --dport 80 -d "${dstip}" -j ACCEPT
            fi
        done
        ${IPT} -t nat -A OUTPUT -p tcp --dport 80 -j REDIRECT --to-port "${PROXYPORT:-'8888'}"
    fi

    # Output for backup servers
    for server in ${BACKUPSERVERS}; do
        server_port=$(echo "${server}" | awk -F : '{print $(NF)}')
        server_ip=$(echo "${server}" | sed -e "s/:${server_port}$//")

        if [ -n "${server_ip}" ] && [ -n "${server_port}" ]; then
            if is_ipv6 ${server_ip}; then
                if is_ipv6_enabled; then
                    ${IPT6} -A INPUT -p tcp --sport "${server_port}" --dport 1024:65535 -s "${server_ip}" -m state --state ESTABLISHED,RELATED -j ACCEPT
                fi
            else 
                ${IPT} -A INPUT -p tcp --sport "${server_port}" --dport 1024:65535 -s "${server_ip}" -m state --state ESTABLISHED,RELATED -j ACCEPT
            fi
        else
            printf "${RED}ERROR: unrecognized syntax for BACKUPSERVERS '%s\`. Use space-separated IP:PORT tuples.${RESET}\n" "${server}" >&2
            exit 1
        fi
    done

    # Always allow ICMP
    ${IPT} -A INPUT -p icmp -j ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -A INPUT -p icmpv6 -j ACCEPT
    fi

    # source config file for remaining commands
    if is_legacy_config; then
        source_file_or_error "${config_file}"
    fi

    # IPTables policy
    #################

    # by default DROP INPUT packets
    ${IPT} -P INPUT DROP
    if is_ipv6_enabled; then
        ${IPT6} -P INPUT DROP
    fi

    # by default, no FORWARDING (deprecated for Virtual Machines)
    #echo 0 > /proc/sys/net/ipv4/ip_forward
    #${IPT} -P FORWARD DROP
    #${IPT6} -P FORWARD DROP

    # by default allow OUTPUT packets... but drop UDP packets (see OUTPUTDROP to drop OUTPUT packets)
    ${IPT} -P OUTPUT ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -P OUTPUT ACCEPT
    fi

    ${IPT} -A OUTPUT -o ${INT} -p udp --dport 33434:33523 --match state --state NEW -j ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -A OUTPUT -o ${INT} -p udp --dport 33434:33523 --match state --state NEW -j ACCEPT
    fi

    ${IPT} -A OUTPUT -p udp --match state --state ESTABLISHED,RELATED -j ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -A OUTPUT -p udp --match state --state ESTABLISHED,RELATED -j ACCEPT
    fi

    ${IPT} -A OUTPUT -p udp -j DROP
    if is_ipv6_enabled; then
        ${IPT6} -A OUTPUT -p udp -j DROP
    fi

    # Finish
    ########################

    trap - INT TERM EXIT

    syslog_info "started"
    printf "${GREEN}${BOLD}${NAME} started${RESET}\n"

    # No need to exit on error anymore
    set +e

    report_state_changes
}

stop() {
    syslog_info "stopping"
    printf "${BOLD}${NAME} stopping${RESET}\n"

    printf "${BLUE}flushing all rules and accepting everything${RESET}\n"

    mkdir -p "$(dirname "${STATE_FILE_PREVIOUS}")"
    status_without_numbers > "${STATE_FILE_PREVIOUS}"

    # Delete all rules
    ${IPT} -F INPUT
    if is_ipv6_enabled; then
        ${IPT6} -F INPUT
    fi

    ${IPT} -F OUTPUT
    if is_ipv6_enabled; then
        ${IPT6} -F OUTPUT
    fi

    ${IPT} -F LOG_DROP
    ${IPT} -F LOG_ACCEPT
    ${IPT} -F ONLYTRUSTED
    ${IPT} -F ONLYPRIVILEGIED
    ${IPT} -F NEEDRESTRICT
    if is_ipv6_enabled; then
        ${IPT6} -F LOG_DROP
        ${IPT6} -F LOG_ACCEPT
        ${IPT6} -F ONLYTRUSTED
        ${IPT6} -F ONLYPRIVILEGIED
        ${IPT6} -F NEEDRESTRICT
    fi

    ${IPT} -t mangle -F
    if is_ipv6_enabled; then
        ${IPT6} -t mangle -F
    fi

    if is_docker_enabled; then
        # WARN: IPv6 not yet supported

        ${IPT} -F DOCKER-USER
        ${IPT} -A DOCKER-USER -j RETURN

        ${IPT} -F MINIFW-DOCKER-PUB
        ${IPT} -X MINIFW-DOCKER-PUB
        ${IPT} -F MINIFW-DOCKER-PRIVILEGED
        ${IPT} -X MINIFW-DOCKER-PRIVILEGED
        ${IPT} -F MINIFW-DOCKER-TRUSTED
        ${IPT} -X MINIFW-DOCKER-TRUSTED
    else
        ${IPT} -t nat -F
    fi

    # Accept all
    ${IPT} -P INPUT ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -P INPUT ACCEPT
    fi

    ${IPT} -P OUTPUT ACCEPT
    if is_ipv6_enabled; then
        ${IPT6} -P OUTPUT ACCEPT
    fi
    #${IPT} -P FORWARD ACCEPT
    #${IPT} -t nat -P PREROUTING ACCEPT
    #${IPT} -t nat -P POSTROUTING ACCEPT

    # Delete non-standard chains
    ${IPT} -X LOG_DROP
    ${IPT} -X LOG_ACCEPT
    ${IPT} -X ONLYPRIVILEGIED
    ${IPT} -X ONLYTRUSTED
    ${IPT} -X NEEDRESTRICT
    if is_ipv6_enabled; then
        ${IPT6} -X LOG_DROP
        ${IPT6} -X LOG_ACCEPT
        ${IPT6} -X ONLYPRIVILEGIED
        ${IPT6} -X ONLYTRUSTED
        ${IPT6} -X NEEDRESTRICT
    fi

    rm -f "${STATE_FILE_LATEST}" "${STATE_FILE_CURRENT}"

    syslog_info "stopped"
    printf "${GREEN}${BOLD}${NAME} stopped${RESET}\n"
}

status() {
    printf "${BLUE}#### iptables --list ###############################${RESET}\n"
    ${IPT} --list --numeric --verbose --line-numbers
    printf "\n${BLUE}#### iptables --table nat --list ###################${RESET}\n"
    ${IPT} --table nat --list --numeric --verbose --line-numbers
    printf "\n${BLUE}#### iptables --table mangle --list ################${RESET}\n"
    ${IPT} --table mangle --list --numeric --verbose --line-numbers
    if is_ipv6_enabled; then
        printf "\n${BLUE}#### ip6tables --list ##############################${RESET}\n"
        ${IPT6} --list --numeric --verbose --line-numbers
        printf "\n${BLUE}#### ip6tables --table mangle --list ###############${RESET}\n"
        ${IPT6} --table mangle --list --numeric --verbose --line-numbers
    fi
}

status_without_numbers() {
    printf "${BLUE}#### iptables --list ###############################${RESET}\n"
    ${IPT} --list --numeric
    printf "\n${BLUE}#### iptables --table nat --list ###################${RESET}\n"
    ${IPT} --table nat --list --numeric
    printf "\n${BLUE}#### iptables --table mangle --list ################${RESET}\n"
    ${IPT} --table mangle --list --numeric
    if is_ipv6_enabled; then
        printf "\n${BLUE}#### ip6tables --list ##############################${RESET}\n"
        ${IPT6} --list --numeric
        printf "\n${BLUE}#### ip6tables --table mangle --list ###############${RESET}\n"
        ${IPT6} --table mangle --list --numeric
    fi
}

reset() {
    syslog_info "resetting"
    printf "${BOLD}${NAME} resetting${RESET}\n"

    ${IPT} -Z
    if is_ipv6_enabled; then
        ${IPT6} -Z
    fi

    ${IPT} -t nat -Z

    ${IPT} -t mangle -Z
    if is_ipv6_enabled; then
        ${IPT6} -t mangle -Z
    fi

    syslog_info "reset"
    printf "${GREEN}${BOLD}${NAME} reset${RESET}\n"
}
show_version() {
    cat <<END
${NAME} version ${VERSION}

Copyright 2007-2022 Evolix <info@evolix.fr>.

${NAME} comes with ABSOLUTELY NO WARRANTY.
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.
END
}

case "${1:-''}" in
    start)
        source_configuration
        check_unpersisted_state

        start
    ;;

    stop)
        source_configuration
        check_unpersisted_state

        stop
    ;;

    status)
        source_configuration
        check_unpersisted_state

        status
    ;;

    reset)
        source_configuration
        check_unpersisted_state

        reset
    ;;

    restart)
        source_configuration
        check_unpersisted_state

        stop
        start
    ;;

    version)
        show_version
    ;;

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

exit 0