mdw@git.distorted.org.uk Git - dyndns/blob - bin/update

   1 #! /bin/sh
   2
   3 set -e
   4 . ./dyndns.conf
   5
   6 ## Check that the environment is set up properly.
   7 for i in DYNDNS_ZONE DYNDNS_HOST DYNDNS_SERVER DYNDNS_KEY SSH_CLIENT; do
   8   eval havep=\${$i+t}\${$i-nil}
   9   case $havep in nil) echo >&2 "$0: variable $i unset"; exit 2 ;; esac
  10 done
  11
  12 ## Find the client address.  This may be useful.
  13 set -- $SSH_CLIENT; client=$1
  14
  15 ## Parse the commad line.
  16 set -- $SSH_ORIGINAL_COMMAND
  17
  18 fail_usage () {
  19   cat >&2 <<EOF
  20 usage: $0 COMMAND ARGS...
  21
  22 Commands:
  23         set [-force] HOST [ADDR]
  24         unset HOST
  25 EOF
  26   exit 1
  27 }
  28 getarg='case $# in 0) fail_usage ;; esac; arg=$1; shift'
  29 doneargs='case $# in 0) ;; *) fail_usage ;; esac'
  30
  31 checkhost () {
  32   host=$1
  33
  34   case "$host" in
  35     *..* | .* | *. | *[!-_.a-zA-Z0-9]*)
  36       echo >&2 "$0: invalid hostname"
  37       exit 2
  38       ;;
  39   esac
  40
  41   matchp=nil
  42   for pat in $DYNDNS_HOST; do
  43     case "$host" in $pat) matchp=t ;; esac
  44   done
  45   case $matchp in nil) echo >&2 "$0: hostname not permitted"; exit 2 ;; esac
  46 }
  47
  48 doupdate () {
  49   cmd=$1
  50
  51 nsupdate -k "$DYNDNS_KEY" <<EOF
  52 server $DYNDNS_SERVER
  53 zone $DYNDNS_ZONE
  54 $cmd
  55 send
  56 EOF
  57 }
  58
  59 eval $getarg; cmd=$arg
  60 case "$cmd" in
  61   set)
  62     forcep=nil
  63     eval $getarg
  64     case "$arg" in -force) forcep=t; eval $getarg ;; esac
  65     host=$arg
  66     case "$#,$forcep,$1" in
  67       0,nil,*) addr=$client ;;
  68       0,t,*) fail_usage ;;
  69       *,nil,"$client" | *,t,*) addr=$1; shift ;;
  70       *)
  71         echo >&2 "$0: incorrect address (wanted = $2; found = $addr)"
  72         exit 3
  73         ;;
  74     esac
  75     eval $doneargs
  76     checkhost "$host"
  77     case $addr in
  78       *:*) rrtype=AAAA ;;
  79       *.*) rrtype=A ;;
  80       *) echo >&2 "$0: failed to parse new address"; exit 2 ;;
  81     esac
  82     name=$host.$DYNDNS_ZONE
  83     doupdate "
  84         update delete $name IN $rrtype
  85         update add $name ${DYNDNS_TTL-14400} IN $rrtype $addr"
  86     ;;
  87   unset)
  88     eval $getarg; host=$arg
  89     eval $doneargs
  90     checkhost "$host"
  91     name=$host.$DYNDNS_ZONE
  92     doupdate "update delete $name IN"
  93     ;;
  94   *)
  95     fail_usage
  96     ;;
  97 esac