#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#
# DNS functions
#
# License
# =======
#
# Copyright (C) 2014-2016 Bob Mottram <bob@freedombone.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# DNS
NAMESERVER1='213.73.91.35'
NAMESERVER2='85.214.20.141'

# parameters used when adding a new domain
DDNS_PROVIDER="default@freedns.afraid.org"
DDNS_USERNAME=
DDNS_PASSWORD=

INADYN_REPO="https://github.com/bashrc/inadyn"
INADYN_COMMIT='fadbe17f520d337dfb8d69ee4bf1fcaa23fce0d6'

# web site used to obtain the external IP address of the system
GET_IP_ADDRESS_URL="checkip.two-dns.de"

# other possible services to obtain the external IP address
EXTERNAL_IP_SERVICES=( \
        'https://check.torproject.org/' \
        'https://www.whatsmydns.net/whats-my-ip-address.html' \
        'https://www.privateinternetaccess.com/pages/whats-my-ip/' \
        'http://checkip.two-dns.de' \
        'http://ip.dnsexit.com' \
        'http://ifconfig.me/ip' \
        'http://ipecho.net/plain' \
        'http://checkip.dyndns.org/plain' \
        'http://ipogre.com/linux.php' \
        'http://whatismyipaddress.com/' \
        'http://ip.my-proxy.com/' \
        'http://websiteipaddress.com/WhatIsMyIp' \
        'http://getmyipaddress.org/' \
        'http://www.my-ip-address.net/' \
        'http://myexternalip.com/raw' \
        'http://www.canyouseeme.org/' \
        'http://www.trackip.net/' \
        'http://icanhazip.com/' \
        'http://www.iplocation.net/' \
        'http://www.howtofindmyipaddress.com/' \
        'http://www.ipchicken.com/' \
        'http://whatsmyip.net/' \
        'http://www.ip-adress.com/' \
        'http://checkmyip.com/' \
        'http://www.tracemyip.org/' \
        'http://checkmyip.net/' \
        'http://www.lawrencegoetz.com/programs/ipinfo/' \
        'http://www.findmyip.co/' \
        'http://ip-lookup.net/' \
        'http://www.dslreports.com/whois' \
        'http://www.mon-ip.com/en/my-ip/' \
        'http://www.myip.ru' \
        'http://ipgoat.com/' \
        'http://www.myipnumber.com/my-ip-address.asp' \
        'http://www.whatsmyipaddress.net/' \
        'http://formyip.com/' \
        'http://www.displaymyip.com/' \
        'http://www.bobborst.com/tools/whatsmyip/' \
        'http://www.geoiptool.com/' \
        'http://checkip.dyndns.com/' \
        'http://myexternalip.com/' \
        'http://www.ip-adress.eu/' \
        'http://www.infosniper.net/' \
        'http://wtfismyip.com/' \
        'http://ipinfo.io/' \
        'http://httpbin.org/ip')

function create_freedns_updater {
    if [[ $ONION_ONLY != "no" ]]; then
        return
    fi

    # currently inadyn doesn't work as expected with freeDNS, so this is a workaround
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    if [[ $DDNS_PROVIDER != *"freedns"* ]]; then
        return
    fi
    if [[ $SYSTEM_TYPE == "mesh"* ]]; then
        return
    fi

    # remove any legacy command
    if [ -f /usr/bin/dynamicdns ]; then
        rm /usr/bin/dynamicdns
    fi
    if grep -q "dynamicdns" /etc/crontab; then
        sed -i '/dynamicdns/d' /etc/crontab
    fi

    # add the update command to cron
    if ! grep -q "/usr/local/bin/freedombone-freedns" /etc/crontab; then
        function_check cron_add_mins
        cron_add_mins 3 '/usr/local/bin/freedombone-freedns'
        systemctl restart cron
    fi

    mark_completed $FUNCNAME
}

function add_ddns_domain {
    if [ ! $1 ]; then
        echo $'ddns domain not specified'
        exit 5638
    fi
    CURRENT_DDNS_DOMAIN="$1"
    if [[ $ONION_ONLY != "no" ]]; then
        return
    fi
    if [ ! -f /etc/inadyn.conf ]; then
        echo $'Unable to find inadyn configuration file /etc/inadyn.conf'
        exit 5745
    fi
    if ! grep -q "$DDNS_PROVIDER" /etc/inadyn.conf; then
        echo '' >> /etc/inadyn.conf
        echo "system $DDNS_PROVIDER" >> /etc/inadyn.conf
        echo '  ssl' >> /etc/inadyn.conf
        echo "  checkip-url $GET_IP_ADDRESS_URL /" >> /etc/inadyn.conf
        if [ $DDNS_USERNAME ]; then
            echo "  username $DDNS_USERNAME" >> /etc/inadyn.conf
        fi
        if [ $DDNS_PASSWORD ]; then
            echo "  password $DDNS_PASSWORD" >> /etc/inadyn.conf
        fi
    fi

    if ! grep -q "$CURRENT_DDNS_DOMAIN" /etc/inadyn.conf; then
        echo "  alias $CURRENT_DDNS_DOMAIN" >> /etc/inadyn.conf
    fi
    chmod 600 /etc/inadyn.conf
    systemctl restart inadyn
    systemctl daemon-reload
}

function remove_ddns_domain {
    if [ ! $1 ]; then
        echo $'ddns domain not specified'
        exit 5638
    fi
    CURRENT_DDNS_DOMAIN="$1"
    if [[ $ONION_ONLY != "no" ]]; then
        return
    fi
    if [ ! -f /etc/inadyn.conf ]; then
        echo $'Unable to find inadyn configuration file /etc/inadyn.conf'
        exit 5745
    fi
    if grep -q "$CURRENT_DDNS_DOMAIN" /etc/inadyn.conf; then
        systemctl stop inadyn
        sed -i "/alias $CURRENT_DDNS_DOMAIN/d" /etc/inadyn.conf
        systemctl start inadyn
        systemctl daemon-reload
    fi
}

function configure_dns {
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    # allow changes to resolv.conf
    chattr -i /etc/resolv.conf

    echo 'domain localdomain' > /etc/resolv.conf
    echo 'search localdomain' >> /etc/resolv.conf
    echo "nameserver $NAMESERVER1" >> /etc/resolv.conf
    echo "nameserver $NAMESERVER2" >> /etc/resolv.conf

    # prevent resolv.conf from changing
    chattr +i /etc/resolv.conf

    mark_completed $FUNCNAME
}

function set_hostname {
    DEFAULT_DOMAIN_NAME="$1"

    echo "$DEFAULT_DOMAIN_NAME" > /etc/hostname
    hostname $DEFAULT_DOMAIN_NAME
    echo "$DEFAULT_DOMAIN_NAME" > /etc/mailname

    if grep -q "127.0.1.1" /etc/hosts; then
        sed -i "s/127.0.1.1.*/127.0.1.1       $DEFAULT_DOMAIN_NAME/g" /etc/hosts
    else
        echo "127.0.1.1  $DEFAULT_DOMAIN_NAME" >> /etc/hosts
    fi
}

function set_your_domain_name {
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi

    function_check set_hostname
    set_hostname $DEFAULT_DOMAIN_NAME

    mark_completed $FUNCNAME
}

function configure_firewall_for_dns {
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    if [[ $INSTALLED_WITHIN_DOCKER == "yes" ]]; then
        # docker does its own firewalling
        return
    fi
    iptables -A INPUT -p udp -m udp --dport 1024:65535 --sport 53 -j ACCEPT
    function_check save_firewall_settings
    save_firewall_settings
    mark_completed $FUNCNAME
}

# NOTE: deliberately no exit 0