proxy-arp

#! /bin/sh -
#
# proxy-arp	Set proxy-arp settings in arp cache
#
# chkconfig: 2345 15 85
# description: using the arp command line utility, populate the arp
#              cache with IP addresses for hosts on different media
#              which share IP space.
#  
# Copyright (c)2002 SecurePipe, Inc. - http://www.securepipe.com/
# 
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation, 
# Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
# -- written initially during 1998
#    2002-08-14; Martin A. Brown <mabrown@securepipe.com>
#      - cleaned up and commented extensively
#      - joined the process parsimony bandwagon, and eliminated
#        many unnecessary calls to ifconfig and awk
#

gripe () {  echo "$@" >&2;               }
abort () {  gripe "Fatal: $@"; exit 1;   }

CONFIG=${CONFIG:-/etc/proxy-arp.conf}
[ -r "$CONFIG" ] || abort $CONFIG is not readable

case "$1" in
  start)
        # -- create proxy arp settings according to
        #    table in the config file
        #
        grep -Ev '^#|^$' $CONFIG | {
          while read INTERFACE IPADDR ; do
            [ -z "$INTERFACE" -o -z "$IPADDR" ] && continue
            arp -s $IPADDR -i $INTERFACE -D $INTERFACE pub
          done
        }
	;;
  stop)
	# -- clear the cache for any entries in the
        #    configuration file
        #
        grep -Ev '^#|^$' /etc/proxy-arp.conf | {
          while read INTERFACE IPADDR ; do
            [ -z "$INTERFACE" -o -z "$IPADDR" ] && continue
            arp -d $IPADDR -i $INTERFACE
	  done
        }
	;;
  status)
        arp -an | grep -i perm
	;;
  restart)
	$0 stop
	$0 start
	;;
  *)
	echo "Usage: proxy-arp {start|stop|restart}"
	exit 1
esac

exit 0
#   
# - end of proxy-arp