#!/bin/bash

set -eu -o pipefail

echo "==> Setting up firewall"

has_ipv6=$(cat /proc/net/if_inet6 >/dev/null 2>&1 && echo "yes" || echo "no")

# wait for 120 seconds for xtables lock, checking every 1 second
readonly iptables="iptables --wait 120"
readonly ip6tables="ip6tables --wait 120"

function ipxtables() {
    $iptables "$@"
    [[ "${has_ipv6}" == "yes" ]] && $ip6tables "$@"
}

ipxtables -t filter -N CLOUDRON || true
ipxtables -t filter -F CLOUDRON # empty any existing rules

# first setup any user IP block lists . remove all references in iptables before destroying them
echo "==> Creating ipset cloudron_blocklist"
$iptables -t filter -D DOCKER-USER -m set --match-set cloudron_blocklist src -j DROP || true
sleep 1 # without this there is a race that iptables is still referencing the ipset
ipset destroy cloudron_blocklist  || true
ipset create cloudron_blocklist hash:net maxelem 262144 || true # if you change the size, change network.js size check

echo "==> Creating ipset cloudron_blocklist6"
$ip6tables -D FORWARD -m set --match-set cloudron_blocklist6 src -j DROP || true
sleep 1 # without this there is a race that iptables is still referencing the ipset
ipset destroy cloudron_blocklist6 || true
ipset create cloudron_blocklist6 hash:net family inet6 maxelem 262144 || true  # if you change the size, change network.js size check

/home/yellowtent/box/src/scripts/setblocklist.sh

$iptables -t filter -A CLOUDRON -m set --match-set cloudron_blocklist src -j DROP
$iptables -t filter -I DOCKER-USER 1 -m set --match-set cloudron_blocklist src -j DROP # the DOCKER-USER chain is not cleared on docker restart

$ip6tables -t filter -A CLOUDRON -m set --match-set cloudron_blocklist6 src -j DROP
$ip6tables -I FORWARD 1 -m set --match-set cloudron_blocklist6 src -j DROP # there is no DOCKER-USER chain in ip6tables, bug?

# allow related and establisted connections
echo "==> Opening standard ports"
ipxtables -t filter -A CLOUDRON -m state --state RELATED,ESTABLISHED -j ACCEPT
ipxtables -t filter -A CLOUDRON -p tcp -m tcp -m multiport --dports 22,80,202,443 -j ACCEPT # 202 is the alternate ssh port

# whitelist any user ports. we used to use --dports but it has a 15 port limit (XT_MULTI_PORTS)
echo "==> Opening up user specified ports"
ports_json="/home/yellowtent/platformdata/firewall/ports.json"
if allowed_tcp_ports=$(node -e "console.log(JSON.parse(fs.readFileSync('${ports_json}', 'utf8')).allowed_tcp_ports.join(' '))" 2>/dev/null); then
    for p in $allowed_tcp_ports; do
        ipxtables -A CLOUDRON -p tcp -m tcp --dport "${p}" -j ACCEPT
    done
fi

if allowed_udp_ports=$(node -e "console.log(JSON.parse(fs.readFileSync('${ports_json}', 'utf8')).allowed_udp_ports.join(' '))" 2>/dev/null); then
    for p in $allowed_udp_ports; do
        ipxtables -A CLOUDRON -p udp -m udp --dport "${p}" -j ACCEPT
    done
fi

# LDAP user directory allow list
echo "==> Configuring LDAP allow list"
if ! ipset list cloudron_ldap_allowlist >/dev/null 2>&1; then
    echo "==> Creating the cloudron_ldap_allowlist ipset"
    ipset create cloudron_ldap_allowlist hash:net
fi
ipset flush cloudron_ldap_allowlist

if ! ipset list cloudron_ldap_allowlist6 >/dev/null 2>&1; then
    echo "==> Creating the cloudron_ldap_allowlist6 ipset"
    ipset create cloudron_ldap_allowlist6 hash:net family inet6
fi
ipset flush cloudron_ldap_allowlist6

ldap_allowlist="/home/yellowtent/platformdata/firewall/ldap_allowlist.txt"
# delete any existing redirect rule
$iptables -t nat -D PREROUTING -p tcp --dport 636 -j REDIRECT --to-ports 3004 2>/dev/null || true
$ip6tables -t nat -D PREROUTING -p tcp --dport 636 -j REDIRECT --to-ports 3004 >/dev/null || true
if [[ -f "${ldap_allowlist}" ]]; then
    # without the -n block, any last line without a new line won't be read it!
    while read -r line || [[ -n "$line" ]]; do
        [[ -z "${line}" ]] && continue # ignore empty lines
        [[ "$line" =~ ^#.*$ ]] && continue # ignore lines starting with #
        if [[ "$line" == *":"* ]]; then
            ipset add -! cloudron_ldap_allowlist6 "${line}" # the -! ignore duplicates
        else
            ipset add -! cloudron_ldap_allowlist "${line}" # the -! ignore duplicates
        fi
    done < "${ldap_allowlist}"

    # ldap server we expose 3004 and also redirect from standard ldaps port 636
    $iptables -t nat -I PREROUTING -p tcp --dport 636 -j REDIRECT --to-ports 3004
    $iptables -t filter -A CLOUDRON -m set --match-set cloudron_ldap_allowlist src -p tcp --dport 3004 -j ACCEPT

    $ip6tables -t nat -I PREROUTING -p tcp --dport 636 -j REDIRECT --to-ports 3004
    $ip6tables -t filter -A CLOUDRON -m set --match-set cloudron_ldap_allowlist6 src -p tcp --dport 3004 -j ACCEPT
fi

# turn and stun service (constants.TURN_PORT, constants.TURN_TLS_PORT, constants.TURN_UDP_PORT_START, constants.TURN_UDP_PORT_END)
echo "==> Opening ports for TURN and STUN"
ipxtables -t filter -A CLOUDRON -p tcp -m multiport --dports 3478,5349 -j ACCEPT
ipxtables -t filter -A CLOUDRON -p udp -m multiport --dports 3478,5349 -j ACCEPT
ipxtables -t filter -A CLOUDRON -p udp -m multiport --dports 50000:50100 -j ACCEPT

# ICMPv6 is very fundamental to IPv6 connectivity unlike ICMPv4
echo "==> Allow ICMP"
$iptables -t filter -A CLOUDRON -p icmp --icmp-type echo-request -j ACCEPT
$iptables -t filter -A CLOUDRON -p icmp --icmp-type echo-reply -j ACCEPT
$ip6tables -t filter -A CLOUDRON -p ipv6-icmp -j ACCEPT
# NDP (546) and RA (547) portion of ICMPv6
$ip6tables -t filter -A CLOUDRON -p udp --sport 547 --dport 546 -j ACCEPT

ipxtables -t filter -A CLOUDRON -p udp --sport 53 -j ACCEPT
# for ldap,dockerproxy server (ipv4 only) to accept connections from apps. for connecting to addons and mail container ports, docker already has rules
$iptables -t filter -A CLOUDRON -p tcp -s 172.18.0.0/16 -d 172.18.0.1 -m multiport --dports 3002,3003 -j ACCEPT
$iptables -t filter -A CLOUDRON -p udp -s 172.18.0.0/16 --dport 53 -j ACCEPT # dns responses from docker (127.0.0.11)
ipxtables -t filter -A CLOUDRON -i lo -j ACCEPT # required for localhost connections (mysql)

# log dropped incoming. keep this at the end of all the rules
ipxtables -t filter -A CLOUDRON -m limit --limit 2/min -j LOG --log-prefix "Packet dropped: " --log-level 7
ipxtables -t filter -A CLOUDRON -j DROP

# prepend our chain to the filter table
echo "==> Adding cloudron filter chain"
$iptables -t filter -C INPUT -j CLOUDRON 2>/dev/null || $iptables -t filter -I INPUT -j CLOUDRON
$ip6tables -t filter -C INPUT -j CLOUDRON 2>/dev/null || $ip6tables -t filter -I INPUT -j CLOUDRON

# masquerading rules for container ports to be accessible using public IP from other containers
echo "==> Adding cloudron postrouting chain"
ipxtables -t nat -N CLOUDRON_POSTROUTING || true
ipxtables -t nat -F CLOUDRON_POSTROUTING # empty any existing rules

$iptables -t nat -A CLOUDRON_POSTROUTING -s 172.18.0.0/16 -d 172.18.0.0/16 -j MASQUERADE
$ip6tables -t nat -A CLOUDRON_POSTROUTING -s fd00:c107:d509::/64 -d fd00:c107:d509::/64 -j MASQUERADE

$iptables -t nat -C POSTROUTING -j CLOUDRON_POSTROUTING 2>/dev/null || $iptables -t nat -I POSTROUTING -j CLOUDRON_POSTROUTING
$ip6tables -t nat -C POSTROUTING -j CLOUDRON_POSTROUTING 2>/dev/null || $ip6tables -t nat -I POSTROUTING -j CLOUDRON_POSTROUTING

# Setup rate limit chain (the recent info is at /proc/net/xt_recent)
echo "==> Setup rate limit chain"
ipxtables -t filter -N CLOUDRON_RATELIMIT || true
ipxtables -t filter -F CLOUDRON_RATELIMIT # empty any existing rules

# log dropped incoming. keep this at the end of all the rules
echo "==> Setup logging"
ipxtables -t filter -N CLOUDRON_RATELIMIT_LOG || true
ipxtables -t filter -F CLOUDRON_RATELIMIT_LOG # empty any existing rules
ipxtables -t filter -A CLOUDRON_RATELIMIT_LOG -m limit --limit 2/min -j LOG --log-prefix "IPTables RateLimit: " --log-level 7
ipxtables -t filter -A CLOUDRON_RATELIMIT_LOG -j DROP

# http https . 5000 requests per second per IP
for port in 80 443; do
    ipxtables -A CLOUDRON_RATELIMIT -p tcp --syn --dport ${port} -m connlimit --connlimit-above 5000 -j CLOUDRON_RATELIMIT_LOG
done

# ssh and sftp. 5 connections per 10 seconds per IP
for port in 22 202 222; do
    ipxtables -A CLOUDRON_RATELIMIT -p tcp --dport ${port} -m state --state NEW -m recent --set --name "public-${port}"
    ipxtables -A CLOUDRON_RATELIMIT -p tcp --dport ${port} -m state --state NEW -m recent --update --name "public-${port}" --seconds 10 --hitcount 5 -j CLOUDRON_RATELIMIT_LOG
done

# ldaps
for port in 636 3004; do
    ipxtables -A CLOUDRON_RATELIMIT -p tcp --syn --dport ${port} -m connlimit --connlimit-above 5000 -j CLOUDRON_RATELIMIT_LOG
done

# docker translates (dnat) 25, 587, 993, 4190 in the PREROUTING step . 50 connections per second per app
for port in 2525 4190 9993; do
    $iptables -A CLOUDRON_RATELIMIT -p tcp --syn ! -s 172.18.0.0/16 -d 172.18.0.0/16 --dport ${port} -m connlimit --connlimit-above 50 -j CLOUDRON_RATELIMIT_LOG
done

# msa, ldap, imap, sieve, pop3 . 500 connections per second per app
for port in 2525 3002 4190 9993 9995; do
    $iptables -A CLOUDRON_RATELIMIT -p tcp --syn -s 172.18.0.0/16 -d 172.18.0.0/16 --dport ${port} -m connlimit --connlimit-above 500 -j CLOUDRON_RATELIMIT_LOG
done

# cloudron docker network: mysql postgresql redis mongodb. 5000 connections per second per app
for port in 3306 5432 6379 27017; do
    $iptables -A CLOUDRON_RATELIMIT -p tcp --syn -s 172.18.0.0/16 -d 172.18.0.0/16 --dport ${port} -m connlimit --connlimit-above 5000 -j CLOUDRON_RATELIMIT_LOG
done

# Add the rate limit chain to input chain
$iptables -t filter -C INPUT -j CLOUDRON_RATELIMIT 2>/dev/null || $iptables -t filter -I INPUT 1 -j CLOUDRON_RATELIMIT
$ip6tables -t filter -C INPUT -j CLOUDRON_RATELIMIT 2>/dev/null || $ip6tables -t filter -I INPUT 1 -j CLOUDRON_RATELIMIT

# Workaround issue where Docker insists on adding itself first in FORWARD table
ipxtables -D FORWARD -j CLOUDRON_RATELIMIT || true
ipxtables -I FORWARD 1 -j CLOUDRON_RATELIMIT

echo "==> Adding cloudron output chain"
ipxtables -t filter -N CLOUDRON_OUTPUT || true
ipxtables -t filter -F CLOUDRON_OUTPUT # empty any existing rules

# turn - mitigate reflection/amplification attack with UDP . The 5349 port is DTLS/UDP and not affected. https://github.com/coturn/coturn/pull/1588
# hashlimit-above is applied _after_ allowing a hashlimit-burst
sudo iptables -t filter -A CLOUDRON_OUTPUT -p udp --sport 3478 -m hashlimit --hashlimit-name turn-401 --hashlimit-above 10/second --hashlimit-burst 30 --hashlimit-mode dstip -j CLOUDRON_RATELIMIT_LOG

# Add the ouput rate limit chain to output chain
$iptables -t filter -C OUTPUT -j CLOUDRON_OUTPUT 2>/dev/null || $iptables -t filter -I OUTPUT 1 -j CLOUDRON_OUTPUT
$ip6tables -t filter -C INPUT -j CLOUDRON_OUTPUT 2>/dev/null || $ip6tables -t filter -I OUTPUT 1 -j CLOUDRON_OUTPUT