#!/bin/sh

#
# meant to be installed as /sbin/ifup-local or called from there
# [ a patch should be sent to the initscripts maintainers to add this ]
#
#
# Calling arguments available in /etc/sysconfig/network-scripts/ifcfg-DEV:
#
# UPDATEDNS=yes
#    enables this script to do its thing
#
# NSUPDATE=nsupdate
#    The name (or path) to the nsupdate binary
#
# UPDATEDNSNAME="HOSTNAME"
# UPDATEDNSNAME="NAME1 NAME2"
#    updates this dns HOSTNAME (or multiple names).  If not specified, the
#    output of hostname will be used.
#
# UPDATEAAAA=yes
#    enables updating AAAA (IPv6 old style records) if a global IPv6
#    has been assigned to the device.
#
# If a secure (via a TSIG key) transaction is to be used, then one of
# these should be used (in order of precedence.  For simplicity, you
# probably want to pick option 1, 4 or 5):
#
#   /etc/sysconfig/network-scripts/key-HOSTNAME.key
#   /etc/sysconfig/network-scripts/key-HOSTNAME.private
#      Keys to use for authenticating an update for a single host, as
#      generated by the dnssec-keygen program.  This is the only way
#      currently to specify different keys to be used for updating
#      different hosts.  Both files are required.
#
#   KEYARGS=args
#      Specifies your own keying arguments passed to nsupdate.
#      Overrides the above arguments.
#
#   UPDATEDNSKEYFILE=KEYFILE
#      Should point to a dnssec (TSIG) key file if one should be used.
#      Note that both the .key and .private files must be present, but
#      just the .key file needs to be pointed to.  It will be used for
#      all the transactions for all updates.
#
#   UPDATEDNSKEY=DNSKEY
#      Should be a DNSKEY value suitable for passing to nsupdate's -y
#      argument
#
#   /etc/sysconfig/network-scripts/key-DEVICE.key
#   /etc/sysconfig/network-scripts/key-DEVICE.private
#      Keys to use for authenticating updates for addresses on a
#      particular DEVICE (like "eth0").  Both files are required.
#
#
# To generate key files use:
#     dnssec-keygen -a HMAC-MD5 -b 128 -n ENTITY HOSTNAME
#        (only replace the HOSTNAME argument with the fully qualified
#        hostname.  The command will output a file name (2 actually: a
#        .key and a .private) that can be moved to the above locations

cd /etc/sysconfig/network-scripts
. network-functions

[ -f ../network ] && . ../network

DEVICE=$1
CONFIG=/etc/sysconfig/network-scripts/ifcfg-$DEVICE
CFGKEYFILE=/etc/sysconfig/network-scripts/key-ifcfg-$DEVICE.key
source_config

if [ "$UPDATEDNS" ] ; then
  #
  # defaults
  #
  [ -z "$UPDATEDNSNAME" ] && UPDATEDNSNAME=`hostname`
  [ -z "$UPDATEDNSTTL" ] && UPDATEDNSTTL=600
  [ -z "$NSUPDATE" ] && NSUPDATE="nsupdate"

  #
  # get the device's ip address
  #
  IPADDR=`LANG= LC_ALL= ifconfig ${DEVICE} | grep 'inet addr' |
       awk -F: '{ print $2 } ' | awk '{ print $1 }'`

  if [ "$UPDATEAAAA" = "yes" ] ; then
    IP6ADDR=`LANG= LC_ALL= ifconfig ${DEVICE} | grep 'inet6 addr' |
          grep 'Global' | sed 's/.*addr: *//;s/\/.*//;'`
  fi

  #
  # see if a key or a key file has been specified or is found
  #
  if [ -z "$KEYARGS" ] ; then
    if [ -n "$UPDATEDNSKEYFILE" ] ; then
      KEYARGS="-k $UPDATEDNSKEYFILE"
    elif [ -n "$UPDATEDNSKEY" ] ; then
      KEYARGS="-y $UPDATEDNSKEY"
    elif [ -f${CFGKEYFILE} ] ; then
      KEYARGS="-k ${CFGKEYFILE}"
    fi
  fi

  for name in $UPDATEDNSNAME ; do

    if [ "$UPDATEAAAA" = "yes" ] ; then
        IP6AAAALINE="update add ${name}. $UPDATEDNSTTL IN AAAA $IP6ADDR"
    fi

    #
    # allow for host-specific keys
    #
    if [ -f key-${name}.key ] ; then
      LOCALKEYARGS="-k key-${name}.key"
    else
      LOCALKEYARGS="$KEYARGS"
    fi

    #
    # perform the update
    #   - delete the old records for the name
    #   - adds the new address to the now empty record name
    #
    $NSUPDATE $LOCALKEYARGS <<EOF
update delete ${name}.
update add ${name}. $UPDATEDNSTTL IN A $IPADDR
$IP6AAAALINE
send
EOF

  done

fi