nsd/nsd-dynipwatch

   1 #!/bin/bash
   2
   3 logfile=
   4 watchfile=
   5
   6 while true; do
   7         case $1 in
   8                 --log) logfile=$2; shift ;;
   9                 --watchfile) watchfile=$2; shift ;;
  10                 -h|--help)
  11                         echo "$0 [--log logfile] [--watchfile /tmp/\${host}.ip] zonefile host"
  12                         exit 0
  13                         ;;
  14                 *) break ;;
  15         esac
  16         shift
  17 done
  18
  19
  20 zonefile=$1
  21 host=$2
  22 [ -z "${watchfile}" ] && watchfile=/tmp/${host}.ip
  23 [ -z "${logfile}" ] && logfile="/var/log/nsd-dynipwatch-${host}.log"
  24
  25
  26 echo "Watch ${watchfile} for host ${host} and update ${zonefile}. Logfile: ${logfile}"
  27
  28
  29 function getAddrFromZonefile # <host> <zonefile>
  30 {
  31         egrep "^$1\\s.*\\sA\\s.*" $2 | egrep -o "([0-9]+\\.)+[0-9]+"
  32 }
  33
  34 function setAddrInZonefile # <host> <zonefile> <addr>
  35 {
  36         sed -i -e "s_^\\($1\\s.*A\\s.*\\s\\)\\([0-9]\\+\\.\\)\\+[0-9]\\+_\\1$3_g" "$2"
  37 }
  38
  39 function getSerialFromZonefile # <zonefile>
  40 {
  41         awk '/; serial/{print$1}' "$1"
  42 }
  43
  44 function setSerialInZonefile # <zonefile> <serial>
  45 {
  46         sed -i -e "s_^\\(.*\\s\\)[0-9]\+\\(\\s\\+; serial.*\\)_\\1$2\\2_g" "$1"
  47 }
  48
  49 function run()
  50 {
  51         touch ${watchfile}
  52         while true; do
  53                 inotifywait -q -t 30 -e close_write "${watchfile}"  > /dev/null
  54                 ret=$?
  55                 [ "$ret" = "0" ] || continue
  56
  57                 oldip=`getAddrFromZonefile "${host}" "${zonefile}"`
  58                 newip=`cat ${watchfile}`
  59                 echo "`date '+%a %F %T'` :: ${oldip} => ${newip}."
  60
  61                 if ! echo "${newip}" | egrep -q "^([0-9]+\\.)+[0-9]+$"  ; then
  62                         echo "Wrong format of new IP address."
  63                         continue
  64                 fi
  65
  66                 if ! [ "${oldip}" = "${newip}" ]; then
  67                         serial=`getSerialFromZonefile "${zonefile}"`
  68                         serial=$(( $serial + 1))
  69                         echo " Update IP address. New serial ${serial}."
  70                         setAddrInZonefile "${host}" "${zonefile}" "${newip}"
  71                         setSerialInZonefile "${zonefile}" "${serial}"
  72                         nsdc rebuild && nsdc reload && nsdc notify
  73                 fi
  74         done
  75 }
  76
  77
  78 run >> $logfile
  79