#!/bin/bash
### BEGIN INIT INFO
# Provides: ynh-hotspot
# Required-Start:    $network $remote_fs $syslog $all
# Required-Stop:     $network $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Set prerequisites for wifi hotspot.
# Description:       Set prerequisites for wifi hotspot.
### END INIT INFO

# Wifi Hotspot app for YunoHost 
# Copyright (C) 2015 Julien Vaubourg <julien@vaubourg.com>
# Contribute at https://github.com/jvaubourg/hotspot_ynh
# 
# 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/>.

# Functions
## State functions

has_vpnclient_app() {
  [ -e /tmp/.ynh-vpnclient-started ]
}

has_ip6delegatedprefix() {
  [ "${ynh_ip6_net}" != none ]
}

is_nat_set() {
  internet_device=${1}

  iptables -nvt nat -L POSTROUTING | grep MASQUERADE | grep -q "${internet_device}"
}

is_ip4nataddr_set() {
  ip address show dev "${ynh_wifi_device}" 2> /dev/null | grep -q "${ynh_ip4_nat_prefix}.1/24"
}

is_ip6addr_set() {
  ip address show dev "${ynh_wifi_device}" 2> /dev/null | grep -q "${ynh_ip6_addr}/64"
}

is_forwarding_set() {
  ip6=$(sysctl net.ipv6.conf.all.forwarding | awk '{ print $NF; }')
  ip4=$(sysctl net.ipv4.conf.all.forwarding | awk '{ print $NF; }')

  [ "${ip6}" -eq 1 -a "${ip4}" -eq 1 ]
}

is_dhcpdv6_set() {
  [ -e /etc/dnsmasq.d/dhcpdv6.conf ]
}

is_dhcpdv4_set() {
  [ -e /etc/dnsmasq.d/dhcpdv4.conf ]
}

is_hostapd_running() {
  service hostapd status &> /dev/null

  if [ $? -eq 0 ]; then

    # If the wifi antenna was unplugged
    if ip link show dev "${ynh_wifi_device}" | grep -q DOWN; then
      service hostapd stop &> /dev/null
      return 1
    fi

    return 0
  fi

  return 1
}

is_dnsmasq_running() {
  service dnsmasq status &> /dev/null
}

is_running() {
  ( has_ip6delegatedprefix && is_ip6addr_set && is_dhcpdv6_set || ! has_ip6delegatedprefix )\
  && is_nat_set "${new_internet_device}" && is_ip4nataddr_set && is_forwarding_set && is_hostapd_running\
  && is_dhcpdv4_set && is_dnsmasq_running
}

## Setters

set_nat() {
  internet_device=${1}

  iptables -t nat -A POSTROUTING -o "${internet_device}" -j MASQUERADE
}

set_ip4nataddr() {
  ip address add "${ynh_ip4_nat_prefix}.1/24" dev "${ynh_wifi_device}"
}

set_ip6addr() {
  ip address delete "${ynh_ip6_addr}/64" dev tun0 &> /dev/null
  ip address add "${ynh_ip6_addr}/64" dev "${ynh_wifi_device}"
}

set_forwarding() {
  sysctl -w net.ipv6.conf.all.forwarding=1 > /dev/null
  sysctl -w net.ipv4.conf.all.forwarding=1 > /dev/null
}

set_dhcpd() {
  if has_ip6delegatedprefix; then
    cp /etc/dnsmasq.d.tpl/dhcpdv6.conf.tpl /etc/dnsmasq.d/dhcpdv6.conf
  
    sed "s|<TPL:WIFI_DEVICE>|${ynh_wifi_device}|g" -i /etc/dnsmasq.d/dhcpdv6.conf
    sed "s|<TPL:IP6_NET>|${ynh_ip6_net}|g" -i /etc/dnsmasq.d/dhcpdv6.conf
    sed "s|<TPL:IP6_DNS0>|${ynh_ip6_dns0}|g" -i /etc/dnsmasq.d/dhcpdv6.conf
    sed "s|<TPL:IP6_DNS1>|${ynh_ip6_dns1}|g" -i /etc/dnsmasq.d/dhcpdv6.conf
  fi

  cp /etc/dnsmasq.d.tpl/dhcpdv4.conf.tpl /etc/dnsmasq.d/dhcpdv4.conf

  sed "s|<TPL:IP4_DNS0>|${ynh_ip4_dns0}|g" -i /etc/dnsmasq.d/dhcpdv4.conf
  sed "s|<TPL:IP4_DNS1>|${ynh_ip4_dns1}|g" -i /etc/dnsmasq.d/dhcpdv4.conf
  sed "s|<TPL:WIFI_DEVICE>|${ynh_wifi_device}|g" -i /etc/dnsmasq.d/dhcpdv4.conf
  sed "s|<TPL:IP4_NAT_PREFIX>|${ynh_ip4_nat_prefix}|g" -i /etc/dnsmasq.d/dhcpdv4.conf
}

start_hostapd() {
  cp /etc/hostapd/hostapd.conf{.tpl,}

  sed "s|<TPL:WIFI_DEVICE>|${ynh_wifi_device}|g" -i /etc/hostapd/hostapd.conf
  sed "s|<TPL:WIFI_SSID>|${ynh_wifi_ssid}|g" -i /etc/hostapd/hostapd.conf
  sed "s|<TPL:WIFI_PASSPHRASE>|${ynh_wifi_passphrase}|g" -i /etc/hostapd/hostapd.conf
  sed "s|<TPL:WIFI_CHANNEL>|${ynh_wifi_channel}|g" -i /etc/hostapd/hostapd.conf

  if [ "${ynh_wifi_n}" -eq 1 ]; then
    sed "s|<TPL:N_COMMENT>||g" -i /etc/hostapd/hostapd.conf
  else
    sed "s|<TPL:N_COMMENT>|#|g" -i /etc/hostapd/hostapd.conf
  fi

  if [ "${ynh_wifi_secure}" -eq 1 ]; then
    sed "s|<TPL:SEC_COMMENT>||g" -i /etc/hostapd/hostapd.conf
  else
    sed "s|<TPL:SEC_COMMENT>|#|g" -i /etc/hostapd/hostapd.conf
  fi

  service hostapd start
}

## Unsetters

unset_nat() {
  internet_device=${1}

  iptables -t nat -D POSTROUTING -o "${internet_device}" -j MASQUERADE
}

unset_ip4nataddr() {
  ip address delete "${ynh_ip4_nat_prefix}.1/24" dev "${ynh_wifi_device}"
}

unset_ip6addr() {
  ip address delete "${ynh_ip6_addr}/64" dev "${ynh_wifi_device}"
}

unset_dhcpd() {
  rm -f /etc/dnsmasq.d/dhcpdv?.conf
  service dnsmasq restart
}

unset_forwarding() {
  sysctl -w net.ipv6.conf.all.forwarding=0 > /dev/null
  sysctl -w net.ipv4.conf.all.forwarding=0 > /dev/null
}

stop_hostapd() {
  service hostapd stop
}

## Tools

moulinette_get() {
  var=${1}

  value=$(yunohost app setting hotspot "${var}")

  if [[ "${value}" =~ "An instance is already running" ]]; then
    echo "${value}" >&2
    exit 1
  fi

  echo "${value}"
} 

moulinette_vpnclient_get() {
  var=${1}

  value=$(yunohost app setting vpnclient "${var}")

  if [[ "${value}" =~ "An instance is already running" ]]; then
    echo "${value}" >&2
    exit 1
  fi

  echo "${value}"
}

moulinette_set() {
  var=${1}
  value=${2}

  msg=$(yunohost app setting hotspot "${var}" -v "${value}")

  if [ ! $? -eq 0 ]; then
    echo "${msg}" >&2
    exit 1
  fi
}

if [ "$1" != restart ]; then

  # Restart php5-fpm at the first start (it needs to be restarted after the slapd start)
  if [ ! -e /tmp/.ynh-hotspot-boot ]; then
    touch /tmp/.ynh-hotspot-boot
    service php5-fpm restart
  fi
  
  # Variables
  
  echo -n "Retrieving Yunohost settings... "
  
  ynh_service_enabled=$(moulinette_get service_enabled)
  ynh_wifi_device=$(moulinette_get wifi_device)
  ynh_wifi_ssid=$(moulinette_get wifi_ssid)
  ynh_wifi_secure=$(moulinette_get wifi_secure)
  ynh_wifi_passphrase=$(moulinette_get wifi_passphrase)
  ynh_wifi_channel=$(moulinette_get wifi_channel)
  ynh_wifi_n=$(moulinette_get wifi_n)
  ynh_ip6_addr=$(moulinette_get ip6_addr)
  ynh_ip6_net=$(moulinette_get ip6_net)
  ynh_ip6_dns0=$(moulinette_get ip6_dns0)
  ynh_ip6_dns1=$(moulinette_get ip6_dns1)
  ynh_ip4_dns0=$(moulinette_get ip4_dns0)
  ynh_ip4_dns1=$(moulinette_get ip4_dns1)
  ynh_ip4_nat_prefix=$(moulinette_get ip4_nat_prefix)
  
  old_internet_device=$(moulinette_get internet_device)
  new_internet_device=$(ip route | awk '/default via/ { print $NF; }')
  
  # Switch the NAT interface if there is a VPN
  ip link show dev tun0 &> /dev/null
  if [ "$?" -eq 0 ]; then
    new_internet_device=tun0
  fi
  
  echo "OK"
  
  # Check IPv6 delegated prefix from vpnclient
  vpnclient_ip6_net=$(moulinette_vpnclient_get ip6_net)
  
  if [ ! -z "${vpnclient_ip6_addr}" ]; then
    if [ "${ynh_ip6_net}" == none ]; then
      ynh_ip6_net=$vpnclient_ip6_net
      ynh_ip6_addr=$(moulinette_vpnclient_get ip6_addr)
    
      moulinette_set ip6_net "${ynh_ip6_net}"
      moulinette_set ip6_addr "${ynh_ip6_addr}"
    else
      if [ "${ynh_ip6_net}" != "${vpnclient_ip6_net}" ]; then
        echo "[WARN] The IPv6 delegated prefix is different from the vpnclient one"
      fi
    fi
  fi

fi

# Script

case "$1" in
  start)
    if is_running; then
      echo "Already started"
    elif [ "${ynh_service_enabled}" -eq 0 ]; then
      echo "Disabled service"
    else
      echo "[hotspot] Starting..."
      touch /tmp/.ynh-hotspot-started

      if [ "${new_internet_device}" == tun0 ]; then
        moulinette_set vpnclient yes
      else
        moulinette_set vpnclient no
      fi

      # Check old state of the ipv4 NAT settings
      if [ ! -z "${old_internet_device}" -a "${new_internet_device}" != "${old_internet_device}" ]\
         && is_nat_set "${old_internet_device}"; then

        unset_nat "${old_internet_device}"
      fi

      # Set ipv4 NAT
      if ! is_nat_set "${new_internet_device}"; then
        echo "Set NAT"
        set_nat "${new_internet_device}"
      fi

      # Set ipv4 NAT address
      if ! is_ip4nataddr_set; then
        echo "Set IPv4 NAT address"
        set_ip4nataddr
      fi

      # Set the ipv6 address
      if has_ip6delegatedprefix && ! is_ip6addr_set; then
        echo "Set IPv6 address"
        set_ip6addr
      fi

      # Set forwarding for ipv6 and ipv4
      if ! is_forwarding_set; then
        echo "Set forwarding"
        set_forwarding
      fi

      # Run hostapd
      if ! is_hostapd_running; then
        echo "Run hostapd"
        start_hostapd
      fi

      # Run DHCP servers
      if ( has_ip6delegatedprefix && ! is_dhcpdv6_set ) || ! is_dhcpdv4_set; then
        echo "Set DHCP servers (dnsmasq)"
        set_dhcpd
      fi

      service bind9 stop &> /dev/null
      service dnsmasq restart

      # Update dynamic settings
      moulinette_set internet_device "${new_internet_device}"
    fi
  ;;
  stop)
    echo "[hotspot] Stopping..."
    rm -f /tmp/.ynh-hotspot-started

    if is_nat_set "${old_internet_device}"; then
      echo "Unset NAT"
      unset_nat "${old_internet_device}"
    fi

    if is_ip4nataddr_set; then
      echo "Unset IPv4 NAT address"
      unset_ip4nataddr
    fi

    if has_ip6delegatedprefix && is_ip6addr_set; then
      echo "Unset IPv6 address"
      unset_ip6addr
    fi 

    if is_forwarding_set; then
      echo "Unset forwarding"
      unset_forwarding
    fi
  
    if is_dhcpdv6_set || is_dhcpdv4_set; then
      echo "Stop DHCP servers"
      unset_dhcpd
    fi

    if is_hostapd_running; then
      echo "Stop hostapd"
      stop_hostapd
    fi

    if has_vpnclient_app; then
      service ynh-vpnclient start
    fi
  ;;
  restart)
    $0 stop
    $0 start
  ;;
  status)
    exitcode=0

    if [ "${ynh_service_enabled}" -eq 0 ]; then
      echo "[ERR] Hotspot Service disabled"
      exitcode=1
    fi

    echo "[INFO] Autodetected internet interface: ${new_internet_device} (last start: ${old_internet_device})"

    if has_ip6delegatedprefix; then
      echo "[INFO] IPv6 delegated prefix found"
      echo "[INFO] IPv6 address computed from the delegated prefix: ${ynh_ip6_addr}"

      if is_ip6addr_set; then
        echo "[OK] IPv6 address set"
      else
        echo "[ERR] No IPv6 address set"
        exitcode=1
      fi

      if is_dhcpdv6_set; then
        echo "[OK] SLAAC & DHCPv6 server set"
      else
        echo "[ERR] No SLAAC & DHCPv6 server set"
        exitcode=1
      fi
    else
      echo "[INFO] No IPv6 delegated prefix found"
    fi

    if is_dhcpdv4_set; then
      echo "[OK] DHCPv4 server set"
    else
      echo "[ERR] No DHCPv4 server set"
      exitcode=1
    fi

    if is_nat_set "${new_internet_device}"; then
      echo "[OK] IPv4 NAT set"
    else
      echo "[ERR] No IPv4 NAT set"
      exitcode=1
    fi

    if is_ip4nataddr_set; then
      echo "[OK] IPv4 NAT address set"
    else
      echo "[ERR] No IPv4 NAT address set"
      exitcode=1
    fi

    if is_forwarding_set; then
      echo "[OK] IPv6/IPv4 forwarding set"
    else
      echo "[ERR] No IPv6/IPv4 forwarding set"
      exitcode=1
    fi

    if is_dnsmasq_running; then
      echo "[OK] Dnsmasq is running"
    else
      echo "[ERR] Dnsmasq is not running"
      exitcode=1
    fi

    if is_hostapd_running; then
      echo "[OK] Hostapd is running"
    else
      echo "[ERR] Hostapd is not running"
      exitcode=1
    fi

    exit ${exitcode}
  ;;
  *)
    echo "Usage: $0 {start|stop|restart|status}"
    exit 1
  ;;
esac

exit 0