#!/bin/bash
# -------
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along 
# with this program; if not, write to the Free Software Foundation, Inc., 
# 51 Franklin St, Fifth Floor, Boston MA 02110-1301 USA
# --------

set -e

DEFAULT_DIR="/etc/default"
DHCP_DIR="/etc/dhcp3"
DHCPD_DEFAULT="$DEFAULT_DIR/dhcp3-server"
DHCPD_CONF="$DHCP_DIR/dhcpd.conf"
LLIUREX_CONFFILE="dhcp/dhcpd.conf"
LLIUREX_FIX_CONF="$DHCP_DIR/dhcpd.lliurex-fixed.conf"

REG_EXP="^[[:blank:]]*INTERFACES="

VAR_LIST="DNS_SRV_ALIASES SRV_DOMAIN DNS_EXTERNAL_NS SRV_BITMASK SRV_IP SRV_NIC SRV_ALTERNATE_IP"
LLX_GETVAR="/usr/sbin/llxcfg-showvars"

# some checks
LIB_FILE="/usr/share/lliurex/lliurex-srv-common/lliurex-netfuncs.sh"
[ -e "$LIB_FILE" ] || exit 1
. ${LIB_FILE}

gen_lliurex_fix(){
   cat <<EOF
# =====================================
#  ${LLIUREX_FIX_CONF}
#  Lliurex
#  (auto)generado
# =====================================
#
# ATENCIÓN: Este fichero se genera automáticamente, por lo que
#           NO DEBE SER MODIFICADO DIRECTAMENTE
#           ya que los cambios realizados se perderán.
#
EOF

   HOST_NUM=1
   HOST_MAX=`get_dhcp_host_max`
   HOST_IP_LIST="`get_dhcp_host_address 1 ${HOST_MAX}`"
   for HOST_IP in ${HOST_IP_LIST}; do
      HOST_MAC="`get_dhcp_host_mac ${HOST_NUM}`"
      if [ "${HOST_MAC}" ]; then
         HOST_NAME="`get_dhcp_host_name ${HOST_NUM}`"

	if [ -z "$SRV_ALTERNATE_IP" ] ; then 

	    # Only One server in the network
            cat << EOFH
      host ${HOST_NAME} {
         hardware ethernet ${HOST_MAC};
         fixed-address ${HOST_IP};
        # option host-name "lliurex";
        # option host-name "${HOST_NAME}";
        option tftp-server-name "${SRV_IP}";
      }
EOFH

	else

	    # Another server in the network
       	    if [ $((${HOST_NUM} % 2)) -eq 0 ]; then
               cat << EOFH
      host ${HOST_NAME} {
         hardware ethernet ${HOST_MAC};
         fixed-address ${HOST_IP};
        # option host-name "lliurex";
        # option host-name "${HOST_NAME}";
	option tftp-server-name "${SRV_ALTERNATE_IP}";
      }
EOFH
	    else
              cat << EOFH
      host ${HOST_NAME} {
         hardware ethernet ${HOST_MAC};
         fixed-address ${HOST_IP};
        # option host-name "lliurex";
        # option host-name "${HOST_NAME}";
	option tftp-server-name "${SRV_IP}";
      }
EOFH
      	    fi
        fi
      fi 
	HOST_NUM=$((${HOST_NUM}+1))
   done
}

gen_dhcpd_default(){

grep -v "${REG_EXP}"  "${DHCPD_DEFAULT}" 
cat <<EOF
$BEGIN_LLIUREX
INTERFACES="$SRV_NIC"
$END_LLIUREX
EOF

}


#------
# main
#-----

[ -x ${LLX_GETVAR} ] && eval `${LLX_GETVAR} ${VAR_LIST}`

if [ -z "$SRV_NIC" ] ; then
  # if SRV_NIC variable is empty then dhcp configuration cannot be done
  exit 1
fi

if [ ! -f "$DHCPD_DEFAULT" ] ; then
   
  #/etc/default/dhcp3-server file does not exist, no dhcp configuration can be done
  exit 1

else

  # INTERFACES is defined as shell variable, so it may be between ' or "
  # we use sed to remove all this stuff (including `) 
  DEFAULT_INTERFACE="$(sed -ne "/${REG_EXP}/s%\(${REG_EXP}['\"\`]\?\)\([^'\"\`]*\).*$%\2%p" "${DHCPD_DEFAULT}" |tail -1)"
  # INTERFACES is a space separated list

  if ! echo " ${DEFAULT_INTERFACE} " |grep -q " $SRV_NIC " ; then 
     # LliureX interface is not in INTERFACE last value in /etc/default/dhcp3-server 
     gen_dhcpd_default | skel-install "${DHCPD_DEFAULT}"
  fi
 
fi

llxcfg-config read ${LLIUREX_CONFFILE} | skel-install -t ${DHCPD_CONF}

gen_lliurex_fix | skel-install  "${LLIUREX_FIX_CONF}"

exit 0