#!/bin/bash
# dhclient-script for Linux. Dan Halbert, March, 1997.
# Updated for Linux 2.[12] by Brian J. Murrell, January 1999.
# No guarantees about this. I'm a novice at the details of Linux
# networking.

# Notes:

# 0. This script is based on the netbsd script supplied with dhcp-970306.

# 1. ifconfig down apparently deletes all relevant routes and flushes
# the arp cache, so this doesn't need to be done explicitly.

# 2. The alias address handling here has not been tested AT ALL.
# I'm just going by the doc of modern Linux ip aliasing, which uses
# notations like eth0:0, eth0:1, for each alias.

# 3. I have to calculate the network address, and calculate the broadcast
# address if it is not supplied. This might be much more easily done
# by the dhclient C code, and passed on.

function save_previous() {
  if [ -e $1 -a ! -e $1.predhclient ]; then
    mv $1 $1.predhclient 
  fi
}
make_resolv_conf() {
  if [ "${PEERDNS}" == "no" ]; then  
      return 
  fi

  if [ x$reason == xRENEW ]; then 
      if [ "$new_domain_name" == "$old_domain_name" ] && [ "$new_domain_servers" == "$old_domain_servers" ]; then
	  return
      fi
  fi

  if [ -n "$new_domain_name" ] || [ -n "$new_domain_name_servers" ]; then
    cp -fp /etc/resolv.conf /etc/resolv.conf.predhclient
    rscf=`mktemp /tmp/XXXXXX`;
    echo '; generated by /sbin/dhclient-script' > $rscf
    if [ -n "$SEARCH" ]; then
 	echo search $SEARCH >> $rscf
    else
	if [ -n "$new_domain_name" ]; then
 	    echo search $new_domain_name >> $rscf
        fi
    fi
    for nameserver in $new_domain_name_servers; do
      echo nameserver $nameserver >> $rscf
    done
    change_resolv_conf $rscf
    [ -x /sbin/restorecon ] && /sbin/restorecon /etc/resolv.conf >/dev/null 2>&1 
    rm -f $rscf
  fi
}

# Must be used on exit.   Invokes the local dhcp client exit hooks, if any.
exit_with_hooks() {
  exit_status=$1
  if [ -f /etc/dhclient-exit-hooks ]; then
    . /etc/dhclient-exit-hooks
  fi
# probably should do something with exit status of the local script
  exit $exit_status
}

# Invoke the local dhcp client enter hooks, if they exist.
if [ -f /etc/dhclient-enter-hooks ]; then
  exit_status=0
  . /etc/dhclient-enter-hooks
  # allow the local script to abort processing of this state
  # local script must set exit_status variable to nonzero.
  if [ $exit_status -ne 0 ]; then
    exit $exit_status
  fi
fi

# Import Red Hat Linux configuration
cd /etc/sysconfig/network-scripts;
. /etc/sysconfig/network-scripts/network-functions
. /etc/rc.d/init.d/functions

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

CONFIG=$interface

need_config ${CONFIG}

if [ -f "${CONFIG}" ]; then 
    source_config
else
    echo $"$0: configuration for $interface not found. Continuing with defaults." >&2
fi

source_config

release=`uname -r`
relmajor=`echo $release |/bin/cut -f1 -d'.'`
relminor=`echo $release |/bin/cut -f2 -d'.'`

# simple IP arithmetic functions:

function quad2num()
{
    if [ $# -eq 4 ]; then
       let n="$1<<24|$2<<16|$3<<8|$4"
       echo $n;
       return 0;
    fi
    echo '0';
    return 1;
}

function ip2num()
{
    IFS='.' quad2num $1;
}

function num2ip()
{
    let n="$1";
    let o1='(n>>24)&0xff';
    let o2='(n>>16)&0xff';
    let o3='(n>>8)&0xff';
    let o4='n & 0xff';
    echo $o1.$o2.$o3.$o4;
}

function mask()
{   
    ip=$1
    m=$2
    let ip=`IFS='.' ip2num $ip`;
    let m=`IFS='.' ip2num $m`;
    let n='ip&m';
    num2ip $n;
}

function add_default_gateway()
{
        router=$1
	# Handle silly DHCP servers that give us a router not on our subnet:
	routerSubnet=`mask $router $new_subnet_mask`
	mySubnet=`mask $new_ip_address $new_subnet_mask`
	routerUnreachable=0
	if [ "$routerSubnet" != "$mySubnet" ]; then
           if /sbin/arping -q -I $interface -w2 $router; then
	       route add -host $router dev $interface;
           else
	       routerUnreachable=1;
	       echo "dhclient: DHCP router $router is unreachable on DHCP subnet $mySubnet"
	       if [ -x /usr/bin/logger ]; then
		   /usr/bin/logger -p local7.notice -t "NET"  "dhclient: DHCP router $router is unreachable on DHCP subnet $mySubnet";
	       fi;
	   fi;
        fi;
	if [ "$routerUnreachable" -eq 0 ]; then
	    /sbin/ip route replace default via $router dev $interface && return 0;
	fi;
	return 1;
}

function dhconfig()
{
  if [ x$old_ip_address != x ] && [ x$alias_ip_address != x ] && \
		[ x$alias_ip_address != x$old_ip_address ]; then
    # Possible new alias. Remove old alias.
    ifconfig $interface:0- inet 0
  fi

  if [ x$old_ip_address != x ] && [ x$old_ip_address != x$new_ip_address ]; then
    # IP address changed. Bringing down the interface will delete all routes,
    # and clear the ARP cache.
    ifconfig $interface inet 0 down
  fi

  if [ x$old_ip_address = x ] || [ x$old_ip_address != x$new_ip_address ] || \
     [ x$reason = xBOUND ] || [ x$reason = xREBOOT ]; then

    ifconfig $interface inet $new_ip_address $new_subnet_arg \
							$new_broadcast_arg
    # Add a network route to the computed network address.
    if [ $relmajor -lt 2 ] || \
		( [ $relmajor -eq 2 ] && [ $relminor -eq 0 ] ); then
      route add -net $new_network_number $new_subnet_arg dev $interface
      if [ $added_old_broadcast_route -eq 1 ]; then
	  route del default;
      fi;
    fi;
    if [[ ( -z "$GATEWAYDEV" && -z "$GATEWAY" ) || ( -z "$GATEWAY" && ( "$GATEWAYDEV" = "$interface") )  ]]; then
	for router in $new_routers; do
	    add_default_gateway $router && break;
	done
    elif [[ ( -z "$GATEWAYDEV" || ( "$GATEWAYDEV" = "$interface" ) ) && ( -n "$GATEWAY" ) ]]; then
	routerSubnet=`mask $GATEWAY $new_subnet_mask`
	mySubnet=`mask $new_ip_address $new_subnet_mask`
	if [ "$routerSubnet" = "$mySubnet" ]; then
	   ip route replace default via $GATEWAY dev $interface 
	fi;
    fi;
    # static routes
    if [ "x$new_static_routes" != x ]; then
      len=`echo $new_static_routes | awk '{print NF}'`
      i=1
      while [ $i -lt $len ]; do
        target=`echo $new_static_routes | awk "{print \\$$i}"`
        let i=i+1
        gateway=`echo $new_static_routes | awk "{print \\$$i}"`
        let i=i+1
        route add -host $target gw $gateway $interface
      done
    fi
  fi

  if [ x$new_ip_address != x$alias_ip_address ] && [ x$alias_ip_address != x ];
   then
    ifconfig $interface:0- inet 0
    ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
    route add -host $alias_ip_address $interface:0
  fi

  make_resolv_conf

  if [ "${PEERNIS}" = no ]; then
    :
  elif [ -n "$new_nis_domain" ]; then
	domainname "$new_nis_domain"
	save_previous /etc/yp.conf
	let contents=0
	echo '# generated by /sbin/dhclient-script' > /etc/yp.conf
	if [ -n "$new_nis_servers" ]; then
	    for I in $new_nis_servers; do
		echo "domain $new_nis_domain server $I" >> /etc/yp.conf
		let contents=contents+1
	    done
	else
	    echo "domain $new_nis_domain broadcast" >> /etc/yp.conf
	    let contents=contents+1
	fi
        level=`/sbin/runlevel`
	level=${level##*\ }
	[ -x /sbin/restorecon ] && /sbin/restorecon /etc/yp.conf >/dev/null 2>&1
	if ! pkill -HUP ypbind && [ $contents -gt 0 ] && chkconfig --level=$level ypbind; then
	   service ypbind start >/dev/null 2>&1;
        fi
  elif [ -n "$new_nis_servers" ]; then
        save_previous /etc/yp.conf
        echo '# generated by /sbin/dhclient-script' > /etc/yp.conf
	let contents=0
        for I in $new_nis_servers; do
	    echo "ypserver $I" >> /etc/yp.conf
	    let contents=contents+1
        done
        level=`/sbin/runlevel`
	level=${level##*\ }
	[ -x /sbin/restorecon ] && /sbin/restorecon /etc/yp.conf >/dev/null 2>&1
        if ! pkill -HUP ypbind && [ $contents -gt 0 ] && chkconfig --level=$level ypbind; then
	    service ypbind start >/dev/null 2>&1;
        fi
  fi

  if [ "${PEERNTP}" = no ]; then
    :
  elif [ -n "$new_ntp_servers" ] && [ -e /etc/ntp.conf ]; then
      save_previous /etc/ntp.conf
      /bin/egrep -v '(^[\ \	]*server)|(generated by /sbin/dhclient-script)'< /etc/ntp.conf.predhclient > /etc/ntp.conf
      echo '# servers generated by /sbin/dhclient-script' >> /etc/ntp.conf
      localClocks=(`/bin/egrep '^[\ \	]*server[\ \	]+127\.127' /etc/ntp.conf.predhclient | while read s addr rest; do echo $addr; done`)      
      for s in $new_ntp_servers ${localClocks[@]};
      do
 	  echo 'server '$s >> /etc/ntp.conf;
      done
      if [ -e /etc/ntp/step-tickers ]; then
	  save_previous /etc/ntp/step-tickers
	  echo '' > /etc/ntp/step-tickers
	  for s in $new_ntp_servers ${localClocks[@]}; 
	  do
	    echo $s >> /etc/ntp/step-tickers
	  done;
      fi;
      [ -x /sbin/restorecon ] && /sbin/restorecon /etc/ntp.conf /etc/ntp/step-tickers >/dev/null 2>&1
      if [ -x /usr/bin/diff ] && /usr/bin/diff -q /etc/ntp.conf /etc/ntp.conf.predhclient >/dev/null 2>&1; then
	 : ;
      else
	 /sbin/service ntpd condrestart >/dev/null 2>&1
      fi;
  fi

  if [ -n "$new_host_name" ] && need_hostname; then
      hostname $new_host_name
  fi
}

if [ x$new_broadcast_address != x ]; then
  new_broadcast_arg="broadcast $new_broadcast_address"
fi
if [ x$old_broadcast_address != x ]; then
  old_broadcast_arg="broadcast $old_broadcast_address"
fi
if [ x$new_subnet_mask != x ]; then
  new_subnet_arg="netmask $new_subnet_mask"
fi
if [ x$old_subnet_mask != x ]; then
  old_subnet_arg="netmask $old_subnet_mask"
fi
if [ x$alias_subnet_mask != x ]; then
  alias_subnet_arg="netmask $alias_subnet_mask"
fi

if [ x$reason = xMEDIUM ]; then
  # Linux doesn't do mediums (ok, ok, media).
  exit_with_hooks 0
fi

added_old_broadcast_route=0;
if [ x$reason = xPREINIT ]; then
  if [ x$alias_ip_address != x ]; then
    # Bring down alias interface. Its routes will disappear too.
    ifconfig $interface:0- inet 0
  fi
  if [ x$keep_old_ip == xyes ]; then
    ifconfig $interface up
  elif [ $relmajor -lt 2 ] || ( [ $relmajor -eq 2 ] && [ $relminor -eq 0 ] )   then
    ifconfig $interface inet 0.0.0.0 netmask 0.0.0.0 \
		broadcast 255.255.255.255 up
    # Add route to make broadcast work. Do not omit netmask.
    route add default dev $interface netmask 0.0.0.0 && added_old_broadcast_route=1;
  else
    ifconfig $interface 0 up
  fi

  # We need to give the kernel some time to get the interface up.
  sleep 1

  exit_with_hooks 0
fi

if [ x$reason = xARPCHECK ] || [ x$reason = xARPSEND ]; then
  exit_with_hooks 0
fi
  
if [ x$reason = xBOUND ] || [ x$reason = xRENEW ] || \
   [ x$reason = xREBIND ] || [ x$reason = xREBOOT ]; then    
    dhconfig ;
    exit_with_hooks 0
fi

if [ x$reason = xEXPIRE ] || [ x$reason = xFAIL ] || [ x$reason = xRELEASE ] \
   || [ x$reason = xSTOP ]; then
  if [ -f /etc/resolv.conf.predhclient ]; then
     change_resolv_conf /etc/resolv.conf.predhclient
     rm -f /etc/resolv.conf.predhclient
     [ -x /sbin/restorecon ] && /sbin/restorecon /etc/resolv.conf >/dev/null 2>&1
  fi
  if [ -f /etc/ntp.conf.predhclient ]; then
     /bin/mv -f /etc/ntp.conf.predhclient /etc/ntp.conf
     if [ -f /etc/ntp/step-tickers.predhclient ]; then
	 /bin/mv -f /etc/ntp/step-tickers.predhclient /etc/ntp/step-tickers;
     fi
     [ -x /sbin/restorecon ] && /sbin/restorecon /etc/ntp.conf /etc/ntp/step-tickers >/dev/null 2>&1
     service ntpd condrestart >/dev/null 2>&1 
  fi
  if [ -f /etc/yp.conf.predhclient ]; then
     /bin/mv -f /etc/yp.conf.predhclient /etc/yp.conf
     [ -x /sbin/restorecon ] && /sbin/restorecon /etc/yp.conf >/dev/null 2>&1
     pkill -HUP ypbind
  fi 
  if [ x$alias_ip_address != x ]; then
    # Turn off alias interface.
    ifconfig $interface:0- inet 0
  fi
  if [ x$old_ip_address != x ]; then
    # Shut down interface, which will delete routes and clear arp cache.
    ifconfig $interface inet 0 down
  fi
  if [ x$alias_ip_address != x ]; then
    ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
    route add -host $alias_ip_address $interface:0
  fi
  exit_with_hooks 0
fi

if [ x$reason = xTIMEOUT ] && [ "x$new_routers" != 'x' ]; then
  if [ x$alias_ip_address != x ]; then
    ifconfig $interface:0- inet 0
  fi
  ifconfig $interface inet $new_ip_address $new_subnet_arg \
					$new_broadcast_arg
  set $new_routers
  if ping -q -c 1 -w 10 -I $interface $1; then
    dhconfig ;
    exit_with_hooks 0
  fi
  ifconfig $interface inet 0 down
  exit_with_hooks 1
elif [ x$reason = xTIMEOUT ]; then
  exit_with_hooks 1
fi

exit_with_hooks 0
