#!/bin/bash

HostIP=""
Netmask=""
Gateway=""
doconfig=n

get_interface(){
if [ -z $netdevice ];then
  ifnames=`hwinfo --netcard | grep 'Device File:' | cut -f2 -d: |  sed 's/[ \t][ \t]*//g;s/\n/ /'`
  if [ -z $ifnames ];then
    echo Sorry no network interfaces found, perhaps you don\'t have an appropriate
    echo kernel module loaded
    exit
  fi
  for interface in $ifnames
  do
    if [ `ethtool $interface | grep 'Link detected' | cut -f2 -d: | sed 's/[ \t][ \t]*//g'` == yes ];then
      echo Found link on $interface
      netdevice=$interface
      return 
    fi
  done
  echo Couldn\'t find a link on any interface
  echo check cabling and run again
  exit
else
  echo netdevice specified as $netdevice
fi
}

check_ip()
{
# IP address should only contain [0-9.]
if [ :`echo $1| sed 's/[0-9.]//g'`: != :: ];then
  return 1
fi
address=`echo $1 | sed 's/\./ /g'`
if [ `echo $address | wc -w` -ne 4 ];then
  return 1
fi
for octet in $address
do
  if [ $octet -ge 0 -a $octet -le 255 ];then
    /bin/true
  else
    return 1
  fi
done
}

get_hostip(){
while [ -z $HostIP ]
do
  echo -n Please type in your IP address and press enter:
  read TempIP
  check_ip $TempIP;
  if [ $? -ne 0 ];then
    echo That didn\'t look valid
  else
    HostIP=$TempIP
  fi
done
}

get_netmask(){
while [ -z $Netmask ]
do
  echo -n Please type in your netmask and press enter:
  read TempIP
  check_ip $TempIP;
  if [ $? -ne 0 ];then
    echo That didn\'t look valid
  else
    Netmask=$TempIP
  fi
done
}

get_gateway(){
while [ -z $Gateway ]
do
  echo -n Please type in your gateway address and press enter:
  read TempIP
  check_ip $TempIP;
  if [ $? -ne 0 ];then
    echo That didn\'t look valid
  else
    Gateway=$TempIP
  fi
done
}

report_config(){
echo You have requested interface $netdevice to be configured as follows
echo "IP Address :" $HostIP
echo "Netmask    :" $Netmask
echo "Gateway    :" $Gateway
response=-1
while [ $response -lt 0 ]
do
  echo -n Do you wish to continue [Y/N]:
  read response
  if [ -z $response ];then
    response=z
  fi
  response=`echo $response | cut -c1 | tr '[A-Z]' '[a-z]'`
  if [ $response == y ];then
    response=0
    doconfig=y
  elif [ $response == n ];then
    response=1
    doconfig=n
  else
    response=-1
  fi
done
if [ $doconfig == n ];then
  HostIP=""
  Netmask=""
  Gateway=""
fi
}

do_config(){
  ifconfig $netdevice inet $HostIP netmask $Netmask
  route add -net default gw $Gateway $netdevice
}

get_interface
while [ $doconfig == n ]
do
  get_hostip
  get_netmask
  get_gateway
  report_config
done
do_config