bin/client/tdyndns_client

   1 #!/bin/sh
   2
   3 # save as /usr/local/bin/tdyndns
   4
   5 set -u
   6
   7 # debug?
   8
   9 if [ $# -gt 0 ] ; then
  10         DOIT="echo "
  11         set -x
  12 else
  13         DOIT=""
  14 fi
  15
  16 # functions
  17
  18 die() {
  19         echo "$1" >&2
  20         exit 1
  21 }
  22
  23 warn() {
  24         echo "$1" >&2
  25 }
  26
  27 # variables
  28
  29 USERNAME=sue
  30 PASSWORD=hygCithOrs5
  31 HOSTNAME=$(hostname)
  32 ZONE=dyn.example.com
  33 FQDN=$HOSTNAME.$USERNAME.$ZONE
  34 NS=ns.example.com
  35 URL="http://dyndns.example.com/nic/update?hostname=$FQDN&myip="
  36
  37 if [ -z "$HOSTNAME" ] ; then
  38         die "No hostname found."
  39 fi
  40
  41 # data
  42
  43 # alternative: -4 icanhazip.com, -6 icanhazip.com or ipv{4,6}.icanhazip.com
  44 NEWIPV4=$(wget -q -O- http://ipv4.wtfismyip.com/text)
  45 NEWIPV6=$(wget -q -O- http://ipv6.wtfismyip.com/text)
  46
  47 if command -v dig >/dev/null ; then
  48         OLDIPV4=$(dig -t a    +short $FQDN @$NS)
  49         OLDIPV6=$(dig -t aaaa +short $FQDN @$NS)
  50 fi
  51 OLDIPV4=${OLDIPV4:-""}
  52 OLDIPV6=${OLDIPV6:-""}
  53
  54 # actions
  55
  56 # old ipv4 gone
  57 if [ -n "$OLDIPV4" -a -z "$NEWIPV4" ] ; then
  58         $DOIT wget -q -O/dev/null --user=$USERNAME --password=$PASSWORD "${URL}${OLDIPV4}&offline=yes"
  59         logger -t${0##*/} -perr -- "removing $FQDN / $OLDIPV4"
  60 fi
  61
  62 # old ipv6 gone
  63 if [ -n "$OLDIPV6" -a -z "$NEWIPV6" ] ; then
  64         $DOIT wget -q -O/dev/null --user=$USERNAME --password=$PASSWORD "${URL}${OLDIPV6}&offline=yes"
  65         logger -t${0##*/} -perr -- "removing $FQDN / $OLDIPV6"
  66 fi
  67
  68 # new ipv4
  69 if [ -n "$NEWIPV4" -a "$NEWIPV4" != "$OLDIPV4" ] ; then
  70         $DOIT wget -q -O/dev/null --user=$USERNAME --password=$PASSWORD "${URL}${NEWIPV4}"
  71         logger -t${0##*/} -perr -- "updating $FQDN to $NEWIPV4"
  72 fi
  73
  74 # new ipv6
  75 if [ -n "$NEWIPV6" -a "$NEWIPV6" != "$OLDIPV6" ] ; then
  76         $DOIT wget -q -O/dev/null --user=$USERNAME --password=$PASSWORD "${URL}${NEWIPV6}"
  77         logger -t${0##*/} -perr -- "updating $FQDN to $NEWIPV6"
  78 fi