#!/bin/bash
#  _____               _           _
# |   __|___ ___ ___ _| |___ _____| |_ ___ ___ ___
# |   __|  _| -_| -_| . | . |     | . | . |   | -_|
# |__|  |_| |___|___|___|___|_|_|_|___|___|_|_|___|
#
#                              Freedom in the Cloud
#
# TURN server functions
#
# License
# =======
#
# Copyright (C) 2016-2019 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/>.

TURN_PORT=3478
TURN_HTTP_PORT=3407
TURN_ONION_PORT=8110

function generate_turn_key {
    local turnkey="${1}"
    local filepath="${2}"
    local domain="${3}"

    if [[ "$domain" != *'.onion' ]]; then
        if [ ! -f "/etc/ssl/certs/${domain}.dhparam" ]; then
            echo $"/etc/ssl/certs/${domain}.dhparam not found when configuring turn server"
            exit 63
        fi
        cp "/etc/ssl/certs/${domain}.dhparam" "/var/lib/turn/${domain}.dhparam"
        chown turnserver:turnserver "/var/lib/turn/${domain}.dhparam"
        chmod 640 "/var/lib/turn/${domain}.dhparam"

        { echo "tls-listening-port=$TURN_PORT";
          echo 'fingerprint';
          echo 'lt-cred-mech';
          echo 'use-auth-secret';
          echo "static-auth-secret=$turnkey";
          echo "realm=$domain";
          echo 'total-quota=100';
          echo 'bps-capacity=0';
          echo 'stale-nonce';
          echo "cert=/etc/letsencrypt/live/${domain}/fullchain.pem";
          echo "pkey=/etc/letsencrypt/live/${domain}/privkey.pem";
          echo "dh-file=/var/lib/turn/${domain}.dhparam";
          echo 'cipher-list="ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AES:RSA+3DES:!ADH:!AECDH:!MD5"';
          echo 'no-loopback-peers';
          echo 'no-multicast-peers';
          echo 'no-tlsv1';
          echo 'no-tlsv1_1';
          echo 'no-stdout-log';
          echo 'simple-log';
          echo 'log-file=/dev/null'; } > "${filepath}"
    else
        { echo "tls-listening-port=$TURN_PORT";
          echo 'fingerprint';
          echo 'lt-cred-mech';
          echo 'use-auth-secret';
          echo "static-auth-secret=$turnkey";
          echo "realm=$domain";
          echo 'total-quota=100';
          echo 'bps-capacity=0';
          echo 'stale-nonce';
          echo 'no-loopback-peers';
          echo 'no-multicast-peers';
          echo 'no-stdout-log';
          echo 'simple-log';
          echo 'log-file=/dev/null'; } > "${filepath}"
    fi
}

function remove_turn {
    firewall_remove ${TURN_HTTP_PORT}
    firewall_remove ${TURN_PORT}
    systemctl stop turn
    systemctl disable turn
    if [ -f /etc/systemd/system/turn.service ]; then
        rm /etc/systemd/system/turn.service
    fi
    systemctl daemon-reload

    $REMOVE_PACKAGES coturn
    rm -rf /var/lib/turn
    sed -i "/# TURN Server/,/# End of TURN Server/d" "/etc/nginx/sites-available/${DEFAULT_DOMAIN_NAME}"
    remove_onion_service turn ${TURN_ONION_PORT}
    rm /etc/avahi/services/turn.service
    systemctl restart nginx
}

function install_turn {
    curr_default_domain_name=$DEFAULT_DOMAIN_NAME
    if [ "$1" ]; then
        curr_default_domain_name="$1"
        if [[ "$curr_default_domain_name" != "$DEFAULT_DOMAIN_NAME" ]]; then
            if [ -f /var/lib/turn/turnserver.conf ]; then
                rm /var/lib/turn/turnserver.conf
            fi
        fi
    fi
    create_default_web_site "$curr_default_domain_name"

    turn_nginx_site=/etc/nginx/sites-available/$curr_default_domain_name
    if ! grep -q '# End of TURN Server' "$turn_nginx_site"; then
        if [[ "$ONION_ONLY" == "no" ]]; then
            { echo '# TURN Server';
              echo 'server {';
              echo "  listen ${TURN_HTTP_PORT} ssl;";
              echo "  listen [::]:${TURN_HTTP_PORT} ssl;";
              echo "  server_name ${curr_default_domain_name};";
              echo '';
              echo '  # Security'; } >> "$turn_nginx_site"
            function_check nginx_ssl
            nginx_ssl "${curr_default_domain_name}"

            function_check nginx_security_options
            nginx_security_options "${curr_default_domain_name}"
            nginx_robots "${curr_default_domain_name}"

            { echo '  add_header Strict-Transport-Security max-age=15768000;';
              echo '';
              echo '  # Logs';
              echo '  access_log /dev/null;';
              echo '  error_log /dev/null;';
              echo '';
              echo '  # Index';
              echo '  index index.html;';
              echo '';
              echo '  # Location';
              echo '  location / {'; } >> "$turn_nginx_site"
            function_check nginx_limits
            nginx_limits "${curr_default_domain_name}" '15m'
            { echo "      proxy_pass http://localhost:${TURN_PORT};";
              echo "      proxy_set_header X-Forwarded-For \$remote_addr;";
              echo '  }';
              echo '}';
              echo ''; } >> "$turn_nginx_site"
        else
            echo '# TURN Server' >> "$turn_nginx_site"
        fi
        { echo 'server {';
          echo "    listen 127.0.0.1:$TURN_ONION_PORT default_server;";
          echo "    server_name $curr_default_domain_name;";
          echo ''; } >> "$turn_nginx_site"
        function_check nginx_security_options
        nginx_security_options "$curr_default_domain_name"
        { echo '';
          echo '  # Logs';
          echo '  access_log /dev/null;';
          echo '  error_log /dev/null;';
          echo '';
          echo '  # Location';
          echo '  location / {'; } >> "$turn_nginx_site"
        function_check nginx_limits
        nginx_limits "$curr_default_domain_name" '15m'
        { echo "      proxy_pass http://localhost:${TURN_PORT};";
          echo "      proxy_set_header X-Forwarded-For \$remote_addr;";
          echo '  }';
          echo '}';
          echo '# End of TURN Server'; } >> "$turn_nginx_site"
    fi

    export DEBIAN_FRONTEND=noninteractive
    $INSTALL_PACKAGES coreutils coturn \
            curl file gcc git libevent-2.0-5 \
            libevent-dev libffi-dev libffi6 \
            libgnutls28-dev libjpeg62-turbo \
            libjpeg62-turbo-dev libldap-2.4-2 \
            libldap2-dev libsasl2-dev \
            libsqlite3-dev libssl-dev \
            libssl1.1 libtool libxml2 \
            libxml2-dev libxslt1-dev libxslt1.1 \
            make python python-dev \
            python-pip python-psycopg2 \
            python-virtualenv sqlite unzip \
            zlib1g zlib1g-dev

    pip install --upgrade pip==9.0.3
    pip install --upgrade python-ldap
    # calling upgrade option prevents installation on ARM
    pip install lxml

    if [ ! -d /var/lib/turn ]; then
        mkdir /var/lib/turn
    fi

    if [ ! -f /var/lib/turn/turnserver.conf ]; then
        turnkey="$(create_password 30)"
        generate_turn_key "$turnkey" /var/lib/turn/turnserver.conf "$curr_default_domain_name"
    else
        turnkey=$(grep 'static-auth-secret' /var/lib/turn/turnserver.conf | awk -F '=' '{print $2}')
    fi
    write_config_param TURN_KEY "$turnkey"

    adduser --system --home=/var/lib/turn/ --group turnserver
    adduser mailpile debian-tor
    adduser mailpile www-data

    if [ -d /etc/letsencrypt ]; then
        chgrp -R ssl-cert /etc/letsencrypt
        chmod -R g=rX /etc/letsencrypt
        usermod -a -G ssl-cert turnserver
    fi

    chmod -R 700 /var/lib/turn/turnserver.conf
    chown -R turnserver:turnserver /var/lib/turn

    { echo '[Unit]';
      echo 'Description=TURN server';
      echo 'After=network.target nginx.target';
      echo '';
      echo '[Service]';
      echo 'Type=simple';
      echo 'User=turnserver';
      echo "WorkingDirectory=/var/lib/turn";
      echo "ExecStart=/usr/bin/turnserver -c /var/lib/turn/turnserver.conf --pidfile /var/lib/turn/turnserver.pid";
      echo "Environment=REPORT_STATS=\"no\"";
      echo 'Restart=always';
      echo 'RestartSec=10';
      echo '';
      echo '[Install]';
      echo 'WantedBy=multi-user.target'; } > /etc/systemd/system/turn.service
    systemctl enable turn
    systemctl daemon-reload
    systemctl start turn

    if [[ "$ONION_ONLY" == 'no' ]]; then
        firewall_add turn ${TURN_PORT}
        firewall_add turn-http ${TURN_HTTP_PORT}
    fi

    #TURN_ONION_HOSTNAME=$(add_onion_service turn ${TURN_PORT} ${TURN_ONION_PORT})
    add_onion_service turn ${TURN_PORT} ${TURN_ONION_PORT}

    { echo '<?xml version="1.0" standalone="no"?><!--*-nxml-*-->';
      echo '<!DOCTYPE service-group SYSTEM "avahi-service.dtd">';
      echo '<service-group>';
      echo '  <name replace-wildcards="yes">%h TURN</name>';
      echo '  <service>';
      echo '    <type>_turn._tcp</type>';
      echo "    <port>$TURN_PORT</port>";
      echo '  </service>';
      echo '  <service>';
      echo '    <type>_turn._udp</type>';
      echo "    <port>$TURN_PORT</port>";
      echo '  </service>';
      echo '</service-group>'; } > /etc/avahi/services/turn.service

    systemctl restart avahi-daemon
    systemctl restart nginx
}

function change_default_domain_name_turn {
    new_default_domain_name="$1"
    install_turn "$new_default_domain_name"
}

# NOTE: deliberately no exit 0