nsd-dynipwatch

   1 #!/bin/bash
   2
   3 logfile=
   4
   5 while true; do
   6         case $1 in
   7                 --log) logfile=$2; shift ;;
   8                 -h|--help)
   9                         echo "$0 [-f] [--log logfile] zonefile host watchfile"
  10                         exit 0
  11                         ;;
  12                 *) break ;;
  13         esac
  14         shift
  15 done
  16
  17
  18 zonefile=$1
  19 host=$2
  20 watchfile=$3
  21 [ -z "${logfile}" ] && logfile="/var/log/nsd-dynipwatch-${host}.log"
  22
  23 echo "logfile: ${logfile}"
  24
  25
  26
  27 function getAddrFromZonefile # <host> <zonefile>
  28 {
  29         egrep "^$1\\s.*\\sA\\s.*" $2 | egrep -o "([0-9]+\\.)+[0-9]+"
  30 }
  31
  32 function setAddrInZonefile # <host> <zonefile> <addr>
  33 {
  34         sed -i -e "s_^\\($1\\s.*A\\s.*\\s\\)\\([0-9]\\+\\.\\)\\+[0-9]\\+_\\1$3_g" "$2"
  35 }
  36
  37 function getSerialFromZonefile # <zonefile>
  38 {
  39         awk '/; serial/{print$1}' "$1"
  40 }
  41
  42 function setSerialInZonefile # <zonefile> <serial>
  43 {
  44         sed -i -e "s_^\\(.*\\s\\)[0-9]\+\\(\\s\\+; serial.*\\)_\\1$2\\2_g" "$1"
  45 }
  46
  47 function run()
  48 {
  49         while true; do
  50                 inotifywait -q -e close_write "${watchfile}"  > /dev/null
  51                 oldip=`getAddrFromZonefile "${host}" "${zonefile}"`
  52                 newip=`cat ${watchfile}`
  53                 echo "`date '+%a %F %T'` :: ${oldip} => ${newip}."
  54
  55                 if ! echo "${newip}" | egrep -q "^([0-9]+\\.)+[0-9]+$"  ; then
  56                         echo "Wrong format of new IP address."
  57                         continue
  58                 fi
  59
  60                 if ! [ "${oldip}" = "${newip}" ]; then
  61                         serial=`getSerialFromZonefile "${zonefile}"`
  62                         serial=$(( $serial + 1))
  63                         echo " Update IP address. New serial ${serial}."
  64                         setAddrInZonefile "${host}" "${zonefile}" "${newip}"
  65                         setSerialInZonefile "${zonefile}" "${serial}"
  66                         nsdc rebuild && nsdc reload && nsdc notify
  67                 fi
  68         done
  69 }
  70
  71 run >> $logfile
  72