#!/bin/bash
### BEGIN INIT INFO
# Provides: ynh-hotspot
# Required-Start:    $network $remote_fs $syslog
# 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

is_ndproxy_set() {
  proxy=$(ip -6 neigh show proxy)
  [ ! -z "${proxy}" ]
}

is_nat_set() {
  iptables -nt nat -L POSTROUTING | grep -q MASQUERADE
}

is_ip4nataddr_set() {
  ip a s dev <TPL:WIFI_DEVICE> | grep -q <TPL:IP4_NAT_PREFIX>.1/24
}

is_ip6addr_set() {
  ip a s dev <TPL:WIFI_DEVICE> | grep -q <TPL: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_hostapd_running() {
  service hostapd status &> /dev/null
}

is_radvd_running() {
  service radvd status &> /dev/null
}

is_dhcpd_running() {
  service isc-dhcp-server status &> /dev/null
}

is_running() {
  is_ndproxy_set && is_nat_set && is_forwarding_set\
  && is_hostapd_running && is_radvd_running && is_dhcpd_running
}

case "$1" in
  start)
    if is_running; then
      echo "Already correctly set"
    else
      if ! is_ndproxy_set; then
        echo "Set NDP proxy"
        ip -6 neigh add proxy <TPL:IP6_ADDR> dev <TPL:WIFI_DEVICE>
      fi

      if ! is_nat_set; then
        echo "Set NAT"
        iptables -t nat -A POSTROUTING -o <TPL:WIRED_DEVICE> -j MASQUERADE
      fi

      if ! is_ip4nataddr_set; then
        echo "Set IPv4 NAT address"
        ip a a <TPL:IP4_NAT_PREFIX>.1/24 dev <TPL:WIFI_DEVICE>
      fi

      if ! is_ip6addr_set; then
        echo "Set IPv6 address"
        ip a a <TPL:IP6_ADDR>/64 dev <TPL:WIFI_DEVICE>
      fi

      if ! is_forwarding_set; then
        echo "Set forwarding"
        sysctl -w net.ipv6.conf.all.forwarding=1 &> /dev/null
        sysctl -w net.ipv4.conf.all.forwarding=1 &> /dev/null
      fi

      if ! is_hostapd_running; then
        echo "Run hostapd"
        service hostapd start
      fi

      # must be running after hostapd
      if ! is_radvd_running; then
        echo "Run radvd"
        sleep 1
        service radvd start
      fi

      # "options routers" addr (is_ip6addr_set) must be set before
      if ! is_dhcpd_running; then
        echo "Run dhcpd"
        service isc-dhcp-server start
      fi
    fi
  ;;
  stop)
    if is_ndproxy_set; then
      echo "Unset NDP proxy"
      ip -6 neigh del proxy <TPL:IP6_ADDR> dev <TPL:WIFI_DEVICE>
    fi
  
    if is_nat_set; then
      echo "Unset NAT"
      iptables -t nat -D POSTROUTING -o <TPL:WIRED_DEVICE> -j MASQUERADE
    fi

    if is_ip4nataddr_set; then
      echo "Unset IPv4 NAT address"
      ip a d <TPL:IP4_NAT_PREFIX>.1/24 dev <TPL:WIFI_DEVICE>
    fi

    if is_ip6addr_set; then
      echo "Unset IPv6 address"
      ip a d <TPL:IP6_ADDR>/64 dev <TPL:WIFI_DEVICE>
    fi 

    if is_forwarding_set; then
      echo "Unset forwarding"
      sysctl -w net.ipv6.conf.all.forwarding=0 &> /dev/null
      sysctl -w net.ipv4.conf.all.forwarding=0 &> /dev/null
    fi
  
    if is_hostapd_running; then
      echo "Stop hostapd"
      service hostapd stop
    fi
  
    if is_radvd_running; then
      echo "Stop radvd"
      service radvd stop
    fi
  
    if is_dhcpd_running; then
      echo "Stop dhcpd"
      service isc-dhcp-server stop
    fi
  ;;
  restart)
    $0 stop
    $0 start
  ;;
  status)
    exitcode=0

    if is_ndproxy_set; then
      echo "NDP proxy is correctly set"
    else
      echo "NDP proxy is NOT set"
      exitcode=1
    fi

    if is_nat_set; then
      echo "NAT is correctly set"
    else
      echo "NAT is NOT set"
      exitcode=1
    fi

    if is_ip4nataddr_set; then
      echo "IPv4 NAT address is correctly set"
    else
      echo "IPv4 NAT address is NOT set"
      exitcode=1
    fi

    if is_ip6addr_set; then
      echo "IPv6 address is correctly set"
    else
      echo "IPv6 address is NOT set"
      exitcode=1
    fi

    if is_forwarding_set; then
      echo "Forwarding is correctly set"
    else
      echo "Forwarding is NOT set"
      exitcode=1
    fi

    if is_hostapd_running; then
      echo "Hostapd is running"
    else
      echo "Hostapd is NOT running"
      exitcode=1
    fi

    if is_radvd_running; then
      echo "Radvd is running"
    else
      echo "Radvd is NOT running"
      exitcode=1
    fi

    if is_dhcpd_running; then
      echo "Dhcpd is running"
    else
      echo "Dhcpd is NOT running"
      exitcode=1
    fi

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

exit 0