#!/bin/bash
#  _____               _           _
# |   __|___ ___ ___ _| |___ _____| |_ ___ ___ ___
# |   __|  _| -_| -_| . | . |     | . | . |   | -_|
# |__|  |_| |___|___|___|___|_|_|_|___|___|_|_|___|
#
#                              Freedom in the Cloud
#
# DNS functions
#
# License
# =======
#
# Copyright (C) 2014-2018 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='91.239.100.100'
NAMESERVER2='89.233.43.71'
NAMESERVER3='87.118.100.175'
NAMESERVER4='94.75.228.29'
NAMESERVER5='85.25.251.254'
NAMESERVER6='2.141.58.13'

# parameters used when adding a new domain
DDNS_PROVIDER="freedns"
DDNS_USERNAME=
DDNS_PASSWORD=

INADYN_REPO="https://github.com/troglobit/inadyn"
INADYN_COMMIT='3fe26d2235ddda9047cf33e8ed1453bcc3bbbf19'
INADYN_CONFIG_FILE=/etc/inadyn.conf

# 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 update_inadyn_config {
    if [ ! -f "${INADYN_CONFIG_FILE}" ]; then
        return
    fi

    if [[ "$DDNS_PROVIDER" == *'freedns'* ]]; then
        return
    fi

    if ! grep -q "$DDNS_PROVIDER" "${INADYN_CONFIG_FILE}"; then
        if grep -q "{" "${INADYN_CONFIG_FILE}"; then
            sed -i "s|provider .*|provider $DDNS_PROVIDER {|g" "${INADYN_CONFIG_FILE}"
            sed -i "s|username .*|username       = $DDNS_USERNAME|g" "${INADYN_CONFIG_FILE}"
            sed -i "s|password .*|password       = $DDNS_PASSWORD|g" "${INADYN_CONFIG_FILE}"
            sed -i "s|checkip-server .*|checkip-server = $GET_IP_ADDRESS_URL|g" "${INADYN_CONFIG_FILE}"
        else
            # Old inadyn config file format
            # store any previous aliases
            grep 'alias ' "${INADYN_CONFIG_FILE}" > /tmp/inadyn_aliases

            # remove entry for any previous ddns
            sed -i '/system /,$d' "${INADYN_CONFIG_FILE}"

            # add the new provider
            { echo '';
              echo "system $DDNS_PROVIDER";
              echo '  ssl';
              echo "  checkip-url $GET_IP_ADDRESS_URL /"; } >> "${INADYN_CONFIG_FILE}"
            if [ "$DDNS_USERNAME" ]; then
                echo "  username $DDNS_USERNAME" >> "${INADYN_CONFIG_FILE}"
            fi
            if [ "$DDNS_PASSWORD" ]; then
                echo "  password $DDNS_PASSWORD" >> "${INADYN_CONFIG_FILE}"
            fi

            if [ -f /tmp/inadyn_aliases ]; then
                cat /tmp/inadyn_aliases >> "${INADYN_CONFIG_FILE}"
                rm /tmp/inadyn_aliases
            fi
        fi
    else
        if grep -q "{" "${INADYN_CONFIG_FILE}"; then
            sed -i "s|username .*|username       = $DDNS_USERNAME|g" "${INADYN_CONFIG_FILE}"
            sed -i "s|password .*|password       = $DDNS_PASSWORD|g" "${INADYN_CONFIG_FILE}"
            sed -i "s|checkip-server .*|checkip-server = $GET_IP_ADDRESS_URL|g" "${INADYN_CONFIG_FILE}"
        else
            # Old inadyn config file format
            # change username/password for an existing provider
            if [ "$DDNS_USERNAME" ]; then
                if grep -q "  username " "${INADYN_CONFIG_FILE}"; then
                    sed -i "s|  username .*|  username $DDNS_USERNAME|g" "${INADYN_CONFIG_FILE}"
                else
                    echo "  username $DDNS_USERNAME" >> "${INADYN_CONFIG_FILE}"
                fi
            fi
            if [ "$DDNS_PASSWORD" ]; then
                if grep -q "  password " "${INADYN_CONFIG_FILE}"; then
                    sed -i "s|  password .*|  password $DDNS_PASSWORD|g" "${INADYN_CONFIG_FILE}"
                else
                    echo "  password $DDNS_PASSWORD" >> "${INADYN_CONFIG_FILE}"
                fi
            fi
        fi
    fi

    systemctl enable inadyn
    systemctl restart inadyn
}

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[0]}") == "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/${PROJECT_NAME}-freedns" /etc/crontab; then
        function_check cron_add_mins
        cron_add_mins 3 "/usr/local/bin/${PROJECT_NAME}-freedns"
        systemctl restart cron
    fi

    mark_completed "${FUNCNAME[0]}"
}

function add_ddns_domain {
    if [ ! "$1" ]; then
        echo $'ddns domain not specified'
        exit 5638
    fi
    CURRENT_DDNS_DOMAIN="$1"
    if [[ $ONION_ONLY != "no" ]]; then
        return
    fi
    if [ ! "$DDNS_PROVIDER" ]; then
        return
    fi
    if [[ "$DDNS_PROVIDER" == 'none' ]]; then
        return
    fi
    if [ ! -f "${INADYN_CONFIG_FILE}" ]; then
        echo $'Unable to find inadyn configuration file "${INADYN_CONFIG_FILE}"'
        exit 5745
    fi
    if ! grep -q "$DDNS_PROVIDER" "${INADYN_CONFIG_FILE}"; then
        { echo 'period          = 300';
          echo 'user-agent      = Mozilla/5.0';
          echo '';
          echo "provider $DDNS_PROVIDER {";
          echo "    ssl            = true";
          echo "    checkip-ssl    = false";
          echo "    checkip-server = $GET_IP_ADDRESS_URL";
          echo "    username       = $DDNS_USERNAME";
          echo "    password       = $DDNS_PASSWORD";
          echo "    hostname       = { $CURRENT_DDNS_DOMAIN }";
          echo '}'; } > "${INADYN_CONFIG_FILE}"
    else
        sed -i "s|checkip-server .*|checkip-server = $GET_IP_ADDRESS_URL|g" "${INADYN_CONFIG_FILE}"
    fi

    if ! grep -q "$CURRENT_DDNS_DOMAIN" "${INADYN_CONFIG_FILE}"; then
        DDNS_HOSTNAMES=$(grep 'hostname ' "${INADYN_CONFIG_FILE}"| awk -F '{' '{print $2}' | sed 's| }||g')
        sed -i "s|hostname .*|hostname       = {${DDNS_HOSTNAMES}, ${CURRENT_DDNS_DOMAIN} }|g" "${INADYN_CONFIG_FILE}"
    fi
    chmod 600 "${INADYN_CONFIG_FILE}"

    systemctl daemon-reload
    systemctl restart inadyn
}

function remove_ddns_domain {
    if [ ! "$1" ]; then
        echo $'ddns domain not specified'
        exit 5638
    fi
    CURRENT_DDNS_DOMAIN="$1"
    if [[ $ONION_ONLY != "no" ]]; then
        return
    fi
    if [[ "$DDNS_PROVIDER" == 'none' ]]; then
        return
    fi
    if [ ! -f "${INADYN_CONFIG_FILE}" ]; then
        echo $'Unable to find inadyn configuration file "${INADYN_CONFIG_FILE}"'
        exit 5745
    fi
    if grep -q "$CURRENT_DDNS_DOMAIN" "${INADYN_CONFIG_FILE}"; then
        systemctl stop inadyn
        sed -i "s|, ${CURRENT_DDNS_DOMAIN}||g" "${INADYN_CONFIG_FILE}"
        if grep -q "$CURRENT_DDNS_DOMAIN" "${INADYN_CONFIG_FILE}"; then
            sed -i "s|${CURRENT_DDNS_DOMAIN}||g" "${INADYN_CONFIG_FILE}"
        fi
        systemctl daemon-reload
        systemctl start inadyn
    fi
}

function configure_dns {
    if [[ $(is_completed "${FUNCNAME[0]}") == "1" ]]; then
        return
    fi

    apt-get -yq install resolvconf

    resolvconf=/etc/resolvconf/resolv.conf.d/head

    # allow changes to resolv.conf
    chattr -i $resolvconf

    { echo 'domain localdomain';
      echo 'search localdomain';
      echo "nameserver $NAMESERVER1";
      echo "nameserver $NAMESERVER2";
      echo "nameserver $NAMESERVER3";
      echo "nameserver $NAMESERVER4";
      echo "nameserver $NAMESERVER5";
      echo "nameserver $NAMESERVER6"; } > $resolvconf

    # prevent resolv.conf from changing
    resolvconf -u

    mark_completed "${FUNCNAME[0]}"
}

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[0]}") == "1" ]]; then
        return
    fi

    function_check set_hostname
    set_hostname "$DEFAULT_DOMAIN_NAME"

    mark_completed "${FUNCNAME[0]}"
}

function configure_firewall_for_dns {
    if [[ $(is_completed "${FUNCNAME[0]}") == "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[0]}"
}

# NOTE: deliberately no exit 0