#!/bin/bash
#
# Wifi Hotspot app for YunoHost
# Copyright (C) 2015 Julien Vaubourg <julien@vaubourg.com>
# Contribute at https://github.com/labriqueinternet/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() {
  i=${1}

  [ "${ynh_ip6_net[${i}]}" != none ]
}

is_nat_set() {
  internet_device=${1}

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

is_ip4nataddr_set() {
  i=${1}
  dev=$(devfromid "${i}")

  ip address show dev "${dev}" 2> /dev/null | grep -q "${ynh_ip4_nat_prefix[${i}]}.1/24"
}

is_ip6addr_set() {
  i=${1}
  dev=$(devfromid "${i}")

  ip address show dev "${dev}" 2> /dev/null | grep -q "${ynh_ip6_addr[${i}]}/64"
}

is_ip6firewall_set() {
  i=${1}
  dev=$(devfromid "${i}")

  ip6tables -w -nvL FORWARD | grep DROP | grep -q "${dev}"
}

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_dhcpd6_running() {
  i=${1}

  $(ps aux | grep "dhcpdv6-ssid${i}" | grep -qv grep)
}

is_dhcpd4_running() {
  i=${1}

  $(ps aux | grep "dhcpdv4-ssid${i}" | grep -qv grep)
}

is_hostapd_running() {
  systemctl is-active hostapd &> /dev/null
}

is_running() {
  for i in $(seq 0 $((${ynh_multissid} - 1))); do
    ( has_ip6delegatedprefix ${i} && is_ip6addr_set ${i}\
      && ( [ "${ynh_ip6_firewall[${i}]}" -eq 1 ] && is_ip6firewall_set ${i} || [ "${ynh_ip6_firewall[${i}]}" -eq 0 ] )\
      && is_dhcpd6_running ${i} || ! has_ip6delegatedprefix ${i} )\
    && is_ip4nataddr_set ${i} && is_dhcpd4_running ${i}

    if [ ! $? -eq 0 ]; then
      return 1
    fi
  done

  is_hostapd_running && is_forwarding_set && ( [ -z "${new_internet_device}" ] || is_nat_set "${new_internet_device}" )
}

## Setters

set_nat() {
  internet_device=${1}

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

set_ip4nataddr() {
  i=${1}
  dev=$(devfromid "${i}")

  ip address add "${ynh_ip4_nat_prefix[${i}]}.1/24" dev "${dev}"
}

set_ip6addr() {
  i=${1}
  dev=$(devfromid "${i}")

  ip address delete "${ynh_ip6_addr[${i}]}/64" dev tun0 &> /dev/null
  ip address add "${ynh_ip6_addr[${i}]}/64" dev "${dev}"
}

set_ip6firewall() {
  i=${1}
  dev=$(devfromid "${i}")

  ip6tables -w -A FORWARD -i "${dev}" -j ACCEPT
  ip6tables -w -A FORWARD -o "${dev}" -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
  ip6tables -w -A FORWARD -o "${dev}" -j DROP
}

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

start_dhcpd6() {
  i=${1}
  dev=$(devfromid "${i}")

  cp /etc/dnsmasq.dhcpd/dhcpdv6{.conf.tpl,-ssid${i}.conf}

  sed "s|<TPL:WIFI_DEVICE>|${dev}|g" -i /etc/dnsmasq.dhcpd/dhcpdv6-ssid${i}.conf
  sed "s|<TPL:IP6_NET>|${ynh_ip6_net[${i}]}|g" -i /etc/dnsmasq.dhcpd/dhcpdv6-ssid${i}.conf
  sed "s|<TPL:IP6_DNS0>|${ynh_ip6_dns0[${i}]}|g" -i /etc/dnsmasq.dhcpd/dhcpdv6-ssid${i}.conf
  sed "s|<TPL:IP6_DNS1>|${ynh_ip6_dns1[${i}]}|g" -i /etc/dnsmasq.dhcpd/dhcpdv6-ssid${i}.conf

  dnsmasq -C /etc/dnsmasq.dhcpd/dhcpdv6-ssid${i}.conf -p0
}

start_dhcpd4() {
  i=${1}
  dev=$(devfromid "${i}")

  cp /etc/dnsmasq.dhcpd/dhcpdv4{.conf.tpl,-ssid${i}.conf}

  sed "s|<TPL:IP4_DNS0>|${ynh_ip4_dns0[${i}]}|g" -i /etc/dnsmasq.dhcpd/dhcpdv4-ssid${i}.conf
  sed "s|<TPL:IP4_DNS1>|${ynh_ip4_dns1[${i}]}|g" -i /etc/dnsmasq.dhcpd/dhcpdv4-ssid${i}.conf
  sed "s|<TPL:WIFI_DEVICE>|${dev}|g" -i /etc/dnsmasq.dhcpd/dhcpdv4-ssid${i}.conf
  sed "s|<TPL:IP4_NAT_PREFIX>|${ynh_ip4_nat_prefix[${i}]}|g" -i /etc/dnsmasq.dhcpd/dhcpdv4-ssid${i}.conf

  dnsmasq -C /etc/dnsmasq.dhcpd/dhcpdv4-ssid${i}.conf -p0
}

start_hostapd() {
  cp /etc/hostapd/hostapd.conf{.tpl1,}

  ethaddr=$(ip link show dev "${ynh_wifi_device}" | grep link/ether | awk -F: '{ printf "02:%s:%s:%s:%s:00", $2, $3, $4, $5 }')
  ip link set addr "${ethaddr}" dev "${ynh_wifi_device}"

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

  for i in $(seq 0 $((${ynh_multissid} - 1))); do
    cp /etc/hostapd/hostapd.conf{.tpl2,.tmp}

    sed "s|<TPL:WIFI_INTERFACE>|hotspot${i}|g" -i /etc/hostapd/hostapd.conf.tmp
    sed "s|<TPL:WIFI_SSID>|${ynh_wifi_ssid[${i}]}|g" -i /etc/hostapd/hostapd.conf.tmp
    sed "s|<TPL:WIFI_PASSPHRASE>|${ynh_wifi_passphrase[${i}]}|g" -i /etc/hostapd/hostapd.conf.tmp

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

    if [ "${i}" -eq 0 ]; then
      sed "s|<TPL:BSS_COMMENT>|#|g" -i /etc/hostapd/hostapd.conf.tmp
    else
      sed "s|<TPL:BSS_COMMENT>||g" -i /etc/hostapd/hostapd.conf.tmp
    fi

    cat /etc/hostapd/hostapd.conf.tmp >> /etc/hostapd/hostapd.conf
    rm /etc/hostapd/hostapd.conf.tmp
  done

  systemctl start hostapd
}

## Unsetters

unset_nat() {
  internet_device=${1}

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

unset_ip4nataddr() {
  i=${1}
  dev=$(devfromid "${i}")

  ip address delete "${ynh_ip4_nat_prefix[${i}]}.1/24" dev "${dev}"
}

unset_ip6addr() {
  i=${1}
  dev=$(devfromid "${i}")

  ip address delete "${ynh_ip6_addr[${i}]}/64" dev "${dev}"
}

unset_ip6firewall() {
  i=${1}
  dev=$(devfromid "${i}")

  ip6tables -w -D FORWARD -i "${dev}" -j ACCEPT
  ip6tables -w -D FORWARD -o "${dev}" -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
  ip6tables -w -D FORWARD -o "${dev}" -j DROP
}

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

stop_dhcpd6() {
  kill $(ps aux | grep 'dhcpdv6-ssid' | grep -v grep | awk '{ print $2 }')
  rm -f /etc/dnsmasq.d/dhcpdv6-ssid*.conf
}

stop_dhcpd4() {
  kill $(ps aux | grep 'dhcpdv4-ssid' | grep -v grep | awk '{ print $2 }')
  rm -f /etc/dnsmasq.d/dhcpdv4-ssid*.conf
}

stop_hostapd() {
  systemctl stop hostapd
}

## Tools

ynh_setting_get() {
  app=${1}
  setting=${2}

  grep "^${setting}:" "/etc/yunohost/apps/${app}/settings.yml" | sed s/^[^:]\\+:\\s*[\"\']\\?// | sed s/\\s*[\"\']\$//
}

ynh_setting_set() {

    # This is a partial copypasta of the official ynh_app_setting internal helper
    # In particular, we do this instead of relying on 'yunohost app setting' for
    # performance reasons (it takes a few second to run every yunohost commands)
    # and to remove the need for the infamous '--need-lock' option/issue.

    app="$1" key="$2" value="${3:-}" python2.7 - <<EOF
import os, yaml, sys
app = os.environ['app']
key, value = os.environ['key'], os.environ.get('value', None)
setting_file = "/etc/yunohost/apps/%s/settings.yml" % app
assert os.path.exists(setting_file), "Setting file %s does not exists ?" % setting_file
with open(setting_file) as f:
    settings = yaml.load(f)
settings[key] = value
with open(setting_file, "w") as f:
    yaml.safe_dump(settings, f, default_flow_style=False)
EOF

}

devfromid() {
  i=${1}

  if [ "${i}" -eq 0 ]; then
    echo "${ynh_wifi_device}"
  else
    echo "hotspot${i}"
  fi
}

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

  # Restart php7.0-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
    systemctl restart php__PHPVERSION__-fpm
  fi

  # Variables

  echo -n "Retrieving Yunohost settings... "

  ynh_service_enabled=$(systemctl is-enabled ynh-hotspot)
  ynh_wifi_device=$(ynh_setting_get hotspot wifi_device)
  ynh_wifi_channel=$(ynh_setting_get hotspot wifi_channel)
  ynh_multissid=$(ynh_setting_get hotspot multissid)

  IFS='|' read -a ynh_wifi_ssid <<< "$(ynh_setting_get hotspot wifi_ssid)"
  IFS='|' read -a ynh_wifi_secure <<< "$(ynh_setting_get hotspot wifi_secure)"
  IFS='|' read -a ynh_wifi_passphrase <<< "$(ynh_setting_get hotspot wifi_passphrase)"
  IFS='|' read -a ynh_ip6_addr <<< "$(ynh_setting_get hotspot ip6_addr)"
  IFS='|' read -a ynh_ip6_firewall <<< "$(ynh_setting_get hotspot ip6_firewall)"
  IFS='|' read -a ynh_ip6_net <<< "$(ynh_setting_get hotspot ip6_net)"
  IFS='|' read -a ynh_ip6_dns0 <<< "$(ynh_setting_get hotspot ip6_dns0)"
  IFS='|' read -a ynh_ip6_dns1 <<< "$(ynh_setting_get hotspot ip6_dns1)"
  IFS='|' read -a ynh_ip4_dns0 <<< "$(ynh_setting_get hotspot ip4_dns0)"
  IFS='|' read -a ynh_ip4_dns1 <<< "$(ynh_setting_get hotspot ip4_dns1)"
  IFS='|' read -a ynh_ip4_nat_prefix <<< "$(ynh_setting_get hotspot ip4_nat_prefix)"

  old_internet_device=$(ynh_setting_get hotspot internet_device)
  new_internet_device=$(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"
fi

# Script

case "$1" in
  start)
    if is_running; then
      echo "Already started"
    elif [ "${ynh_service_enabled}" != "enabled" ]; then
      echo "Disabled service"
    else

      if [ -z "${ynh_wifi_device}" ]; then
        echo "[ERR] No wifi device selected. Make sure your wifi antenna is plugged-in / available and select it in the Hotspot admin"
        exitcode=1
      fi

      echo "[hotspot] Starting..."
      touch /tmp/.ynh-hotspot-started

      if [ "${new_internet_device}" == tun0 ]; then
        ynh_setting_set hotspot vpnclient yes
      else
        ynh_setting_set hotspot 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 [ ! -z "${new_internet_device}" ] && ! is_nat_set "${new_internet_device}"; then
        echo "Set NAT"
        set_nat "${new_internet_device}"
      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 ${i}

        if [ ! $? -eq 0 ]; then
          exit 1
        fi

        if [ "${ynh_multissid}" -gt 1 ]; then
          i=0; false || while [ $? -ne 0 ]; do
            sleep 1 && (( i++ ))
            [ ${i} -gt 20 ] && stop_hostapd
            [ ${i} -gt 20 ] && exit 1
            ip link show dev hotspot1 &> /dev/null
          done
        else
          sleep 1
        fi
      fi

      # For each registred ssid
      for i in $(seq 0 $((${ynh_multissid} - 1))); do

        # Set ipv4 NAT address
        if ! is_ip4nataddr_set ${i}; then
          echo "hotspot${i}: Set IPv4 NAT address"
          set_ip4nataddr ${i}
        fi

        # Set the ipv6 address
        if has_ip6delegatedprefix ${i} && ! is_ip6addr_set ${i}; then
          echo "hotspot${i}: Set IPv6 address"
          set_ip6addr ${i}
        fi

        # Set ipv6 firewalling
        if has_ip6delegatedprefix ${i} && [ "${ynh_ip6_firewall[${i}]}" -eq 1 ] && ! is_ip6firewall_set ${i}; then
          echo "hotspot${i}: Set IPv6 firewalling"
          set_ip6firewall ${i}
        fi

        # Run DHCPv6 server
        if has_ip6delegatedprefix ${i} && ! is_dhcpd6_running ${i}; then
          echo "hotspot${i}: Start the NDP and DHCPv6 server (dnsmasq)"
          start_dhcpd6 ${i}
        fi

        # Run DHCPv4 server
        if ! is_dhcpd4_running ${i}; then
          echo "hotspot${i}: Start the DHCPv4 server (dnsmasq)"
          start_dhcpd4 ${i}
        fi

      done

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

    if [ ! -z "${old_internet_device}" ] && is_nat_set "${old_internet_device}"; then
      echo "Unset NAT"
      unset_nat "${old_internet_device}"
    fi

    if is_forwarding_set; then
      echo "Unset forwarding"
      unset_forwarding
    fi

    for i in $(seq 0 $((${ynh_multissid} - 1))); do
      if is_ip4nataddr_set ${i}; then
        echo "hotspot${i}: Unset IPv4 NAT address"
        unset_ip4nataddr ${i}
      fi

      if has_ip6delegatedprefix ${i} && is_ip6addr_set ${i}; then
        echo "hotspot${i}: Unset IPv6 address"
        unset_ip6addr ${i}
      fi

      if has_ip6delegatedprefix ${i}  && [ "${ynh_ip6_firewall[${i}]}" -eq 1 ] && is_ip6firewall_set ${i}; then
        echo "hotspot${i}: Unset IPv6 firewalling"
        unset_ip6firewall ${i}
      fi

      if is_dhcpd6_running ${i}; then
        echo "hotspot${i}: Stop the NDP and DHCPv6 server (dnsmasq)"
        stop_dhcpd6 ${i}
      fi

      if is_dhcpd4_running ${i}; then
        echo "hotspot${i}: Stop the DHCPv4 server (dnsmasq)"
        stop_dhcpd4 ${i}
      fi
    done

    if is_hostapd_running; then
      echo "Stop hostapd"
      stop_hostapd
    fi

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

    if [ "${ynh_service_enabled}" != "enabled" ]; then
      echo "[ERR] Hotspot Service disabled"
      exitcode=1
    fi

    if [ -z "${ynh_wifi_device}" ]; then
      echo "[ERR] No wifi device selected. Make sure your wifi antenna is plugged-in / available and select it in the Hotspot admin"
      exitcode=1
    fi

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

    if is_nat_set "${new_internet_device}"; then
      echo "[OK] IPv4 NAT set"
    else
      if [ -z "${new_internet_device}" ]; then
        echo "[INFO] No IPv4 NAT set (no internet interface)"
      else
        echo "[ERR] No IPv4 NAT set"
      fi
      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_hostapd_running; then
      echo "[OK] Hostapd is running"
    else
      echo "[ERR] Hostapd is not running"
      exitcode=1
    fi

    for i in $(seq 0 $((${ynh_multissid} - 1))); do
      if has_ip6delegatedprefix ${i}; then
        echo "[INFO] hotspot${i}: IPv6 delegated prefix found"
        echo "[INFO] hotspot${i}: IPv6 address computed from the delegated prefix: ${ynh_ip6_addr}"

        if is_ip6addr_set ${i}; then
          echo "[OK] hotspot${i}: IPv6 address set"
        else
          echo "[ERR] hotspot${i}: No IPv6 address set"
          exitcode=1
        fi

        if is_ip6firewall_set ${i}; then
          echo "[OK] hotspot${i}: IPv6 firewalling set"
        else
          if [ "${ynh_ip6_firewall[${i}]}" -eq 1 ]; then
            echo "[ERR] hotspot${i}: No IPv6 firewalling set"
          else
            echo "[INFO] hotspot${i}: No IPv6 firewalling set"
          fi
          exitcode=1
        fi

        if is_dhcpd6_running ${i}; then
          echo "[OK] hotspot${i}: NDP and DHCPv6 server (dnsmasq) are running"
        else
          echo "[ERR] hotspot${i}: NDP and DHCPv6 server (dnsmasq) are not running"
          exitcode=1
        fi
      else
        echo "[INFO] hotspot${i}: No IPv6 delegated prefix found"
      fi

      if is_dhcpd4_running ${i}; then
        echo "[OK] hotspot${i}: DHCPv4 server (dnsmasq) is running"
      else
        echo "[ERR] hotspot${i}: DHCPv4 (dnsmasq) is not running"
        exitcode=1
      fi

      if is_ip4nataddr_set ${i}; then
        echo "[OK] hotspot${i}: IPv4 NAT address set"
      else
        echo "[ERR] hotspot${i}: No IPv4 NAT address set"
        exitcode=1
      fi
    done

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

exit 0