add-sshfp.sh

   1 #!/bin/sh
   2 # Script to convert SSHFP Bind format records to djbdns tinydns.
   3 #
   4 # Author: Elan Ruusamäe <glen@pld-linux.org>
   5 #
   6 # Inspired from Perl version
   7 # http://dank.qemfd.net/dankwiki/index.php/SSHFP
   8
   9 # convert decimal to octal
  10 dec2oct() {
  11         echo "ibase=10; obase=8; $1" | bc -l
  12 }
  13
  14 # convert hex to octal
  15 hex2oct() {
  16         # bc wants uppercase hex
  17         local i=$(echo "$1" | tr [a-f] [A-F])
  18         echo "ibase=16; obase=8; $i" | bc -l
  19 }
  20
  21 hostalias=$1
  22 ssh-keygen -f /etc/ssh/ssh_host_rsa_key.pub -r $hostalias | \
  23 while read host in sshfp alg fptype fp; do
  24         out="\\"$(printf "%03d" $(dec2oct $alg))
  25         out=$out"\\"$(printf "%03d" $(dec2oct $fptype))
  26
  27         while [ "$fp" ]; do
  28                 # temp chop off two bytes
  29                 t=${fp#??}
  30                 # take the bytes
  31                 ch=${fp%$t}
  32                 out=$out"\\"$(printf "%03d" $(hex2oct $ch))
  33                 # continue fp
  34                 fp=$t
  35         done
  36         printf ":%s:44:%s:\n" $host $out
  37 done