#!/bin/bash

source /usr/share/yunohost/helpers

wifi_device=$(ynh_app_setting_get --app=$app --key=wifi_device)
captive_portal=$(ynh_app_setting_get --app=$app --key=captive_portal)
ip4_prefix=$(ynh_app_setting_get --app=$app --key=ip4_nat_prefix)
ip6_prefix=$(ynh_app_setting_get --app=$app --key=ip6_net)

iptables -w -N hotspot_fwd
ip6tables -w -N hotspot_fwd

if [[ "${captive_portal}" != "1" ]]
then
    exit 0
fi

for iptables_cmd in iptables ip6tables;
do
    if [[ "${iptables_cmd}" == "iptables" ]]; then
        prefix="${ip4_prefix}"
        ip="${ip4_prefix}.1"
        subnet="${ip4_prefix}.0/24"
    else
        prefix="${ip6_prefix}"
        ip="${ip6_prefix}1"
        subnet="${ip6_prefix}1/64"
    fi

    mac_addresses=$(grep "${prefix}" /etc/hostapd/$app/allowed.csv | cut -d, -f3)

    # Allow to request 4253 port
    $iptables_cmd -w -A INPUT -i "${wifi_device}" -m udp -p udp --dport 4253 -j ACCEPT

    # Drop all packets going on external internet
    $iptables_cmd -w -A hotspot_fwd -s "${subnet}" -j DROP

    # Force to use the fakeDNS
    $iptables_cmd -w -A PREROUTING -i "${wifi_device}" -s "${subnet}" -p udp --dport 53 -j DNAT --to-destination "${ip}:4253"

    # Make things working with DoH 
    # Warning: this rules to ssupport DoH let info in nginx logs on which website the user try to access...
    # Only activating 80 and not 443 reduces a bit the issues.
    # A better approach could be to list all ips used by domains dedicated to captive portal detection.
    $iptables_cmd -w -A PREROUTING -i "${wifi_device}" -s "${subnet}" -p tcp --dport 80 -j DNAT --to-destination "${ip}:80"
    #$iptables_cmd -w -A PREROUTING -i "${wifi_device}" -s "${subnet}" -p tcp --dport 443 -j DNAT --to-destination "${ip}:443"

    # Maybe needed, maybe not (i din't need this when vpn is activated)
    #$iptables_cmd -t nat -A POSTROUTING -o "${wifi_device}" -j MASQUERADE

    # Allow specific mac adress to use external internet
    for mac in ${mac_addresses}; do
        $iptables_cmd -w -I hotspot_fwd 1 -s "${subnet}" -m mac --mac-source "${mac}" -j ACCEPT
        $iptables_cmd -t nat -w -I PREROUTING 1 -i "${wifi_device}" -s "${subnet}" -m mac --mac-source "${mac}" -j ACCEPT
    done

    $iptables_cmd -w -I FORWARD 1 -i "${wifi_device}" -j hotspot_fwd
done
exit 0