#!/bin/sh
# by Nathan 20 December 1995
ETHERS=/etc/ethers
DIR=/usr/operator/arpwatch
DAT=$DIR/arp.dat
CODES=$DIR/ethercodes.dat
NOW=`date`
mv $ETHERS $ETHERS-
cat << eof > $ETHERS
# This file was created from the arpwatch data file
# $DAT by arptoethers
# at $NOW
# DO NOT EDIT. 
eof
sort -t. +3n -4 < $DAT | while read mac ip time hostname
do
# first, look up line in ethercodes.dat
  echo -n '.'  # activity reporting
  prefix=`echo $mac | awk -F: '{printf "%s:%s:%s",$1,$2,$3}'`
  answer=`grep "^$prefix	" $CODES` # tab in pattern eliminates 8:0:9 vs 8:0:90
  found=$?
  if [ $found -eq 0 ] ; then
     name=`echo "$answer" |  # note: lines has some number of tabs in it
                             # we (hopefully) print more than what line has
           awk -F\\t '{printf "%s%s%s%s%s%s\n",$2,$3,$4,$5,$6,$7}'`
     echo "$mac" | awk '{printf "# %-18s = ",$1}'       >> $ETHERS
     echo "$name" >> $ETHERS
  else
     echo "$mac" | awk '{printf "# %-18s = Unknown\n",$1}' >> $ETHERS
  fi
  echo "$mac $ip $hostname" |
  awk '{printf "%-18s\t%-12s\t# %-16s\n",$1,$3,$2}' >> $ETHERS
done
exit 0