iankelling.org Git - distro-setup/blob - dynamic-ip-update

   1 #!/bin/bash
   2 set -eE -o pipefail
   3 trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
   4
   5 fqdn=$(hostname -f)
   6
   7 up4=false
   8 if timeout -s 9 5 ssh-keyscan -p 2220 -t rsa 10.0.0.1 2>/dev/null | grep -qFx '[10.0.0.1]:2220 ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCH+/h1dGEfKEusBblndU2e6QT4wLCm5+yqr/sqh/0X9YfjR7BfWWm8nNmuP55cYc+Wuf5ljB1H1acXEcsl1y8e0j3agHfF0V74FE1N1zz5nn2Ep8NHnmqgEhza38ZxMPh+4p3X7zklEKU7+3SzybKBi8sg0wLzlS2LM0JaUN80zR2sK11Kye3dURUXPk78u5wodOkgcEYRwSYaDMJlUzWP+poRXIDJwFaMQnwmxbl/c84yOyaU0x/d6hFwoRscWecihX+vvBNeSyxR4xr2HDOyUWwJkctyAgt2p7w3tfkXOKcCRzTAjGVIMQLTvo0sG/yJbcyHoEFdFybCsgDvfyYn'; then
   9   # we are on home network
  10   cur4="$(host -4 b8.nz iankelling.org | sed -rn 's/.*has address (.*)/\1/p;T;q')"
  11   if ip4=$(curl -s4 https://iankelling.org/cgi/pubip); then
  12     if [[ $cur4 && $ip4 && $cur4 != $ip4 ]]; then
  13       up4=true
  14     fi
  15   fi
  16 fi
  17
  18 # may not be set yet so allow fail
  19 cur6="$(host -4 -t aaaa $fqdn iankelling.org | sed -rn 's/.*has IPv6 address (.*)/\1/p;T;q')" ||:
  20
  21 up6=false
  22 # maybe we dont have ipv6 working
  23 if out6=$(curl -s6 https://iankelling.org/cgi/pubip) && [[ $out6 ]]; then
  24   dev=$(ip -o a show to $out6 | awk '{print $2}')
  25   # we use slaac with privacy extension, so get our less private more permanent address
  26   mac=$(cat /sys/class/net/$dev/address)
  27
  28   IFS=: read -a f <<<$mac; set -- ${f[@]}
  29   ip6=${out6%:*:*:*:*}:$(printf %x $((0x$1 + 2)))$2:$3'ff:fe'$4:$5$6
  30   # in case we aren't using slaac
  31   if ! ip a | grep "^ *inet6 $ip6/" &>/dev/null; then
  32     ip6=$out6
  33   fi
  34   if [[ $cur6 != $ip6 ]]; then
  35     up6=true
  36   fi
  37 fi
  38
  39
  40 if ! $up4 && ! $up6; then
  41   exit 0
  42 fi
  43
  44 # note, a simpler way to do this would be to ssh and use
  45 # "${SSH_CLIENT%% *}
  46 # to update bind if needed.
  47
  48 f=$(mktemp)
  49 cat >>$f <<EOF
  50 server iankelling.org
  51 zone b8.nz
  52 EOF
  53
  54 if $up4; then
  55   cat >>$f <<EOF
  56 update delete b8.nz. A
  57 update delete wrt.b8.nz. A
  58 update add b8.nz. 300 A $ip4
  59 update add wrt.b8.nz. 300 A $ip4
  60 EOF
  61 fi
  62
  63 if $up6; then
  64   if [[ $HOSTNAME == tp ]]; then
  65     cat >>$f <<EOF
  66 update delete b8.nz. AAAA
  67 update add b8.nz. 60 AAAA $ip6
  68 EOF
  69   fi
  70   cat >>$f <<EOF
  71 update delete $fqdn. AAAA
  72 update add $fqdn. 60 AAAA $ip6
  73 EOF
  74 fi
  75
  76 cat >>$f <<EOF
  77 show
  78 send
  79 answer
  80 quit
  81 EOF
  82
  83 nsupdate -k /p/c/machine_specific/li/filesystem/etc/bind/Kb8.nz.*.private <$f
  84
  85 exit
  86
  87 # # persistent initial setup for this:
  88 # # create files in /a/c/machine_specific/li/filesystem/etc/bind
  89 # # note, conflink also does some group ownership stuff.
  90
  91 mkc /p/c/machine_specific/li/filesystem/etc/bind
  92 s dnssec-keygen -a HMAC-SHA512 -b 512 -n HOST b8.nz
  93 user=$(id -un)
  94 s chown $user:$user *
  95
  96
  97 f=key.b8.nz
  98 cat >$f <<EOF
  99 key b8.nz. {
 100 algorithm HMAC-SHA512;
 101 secret "$(awk '$1 == "Key:" {print $2}' Kb8.nz.*.private)";
 102 };
 103 EOF
 104
 105 chmod 640 [kK]*
 106
 107 myunison -ob li
 108 ssh li conflink
 109 ssh li ser restart bind9