#!/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.
if [ -n "${dhc_dbus}" ]; then
/bin/dbus-send \
--system \
--dest=com.redhat.dhcp \
--type=method_call \
/com/redhat/dhcp/$interface \
com.redhat.dhcp.set \
'string:'"`env | /bin/egrep -v '^(PATH|SHLVL|_|PWD|dhc_dbus)\='`";
if (( ( dhc_dbus & 31 ) == 31 )); then
exit 0;
fi;
fi;
function save_previous() {
if [ -e $1 ]; then
/bin/mv $1 $1.predhclient
else
echo ''> $1.predhclient
fi
}
make_resolv_conf() {
if [ "${PEERDNS}" == "no" ]; then
return
fi
if [ x$reason == xRENEW ] &&
[ "$new_domain_name" == "$old_domain_name" ] &&
[ "$new_domain_name_servers" == "$old_domain_name_servers" ]; then
return;
fi
if [ -n "$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
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 mask_bits()
{
ip=$1
let ip=`IFS='.' ip2num $ip`;
let bits=0
for ((bit=1; '((ip&bit)==0) && (bits < 32)'; 'bit<<=1')) do
let bits+=1
done
let n_bits=32-bits
echo $n_bits
}
function class_bits()
{
let ip=`IFS='.' ip2num $1`;
let bits=32
let mask='255';
for ((i=0; i <= 3; i++, 'mask<<=8')); do
let v='ip&mask';
if [ "$v" -eq 0 ] ; then
let bits-=8;
else
break;
fi;
done;
echo $bits;
}
function routerReachable()
{ # Handle silly DHCP servers that give us a router not on our subnet:
router=$1
routerSubnet=`mask $router $new_subnet_mask`
mySubnet=`mask $new_ip_address $new_subnet_mask`
unreachable=0
if [ "$routerSubnet" != "$mySubnet" ]; then
unreachable=1
if /sbin/arping -f -q -I $interface -w2 $router; then
/sbin/ip route add ${router}/32 dev $interface
if [ $? -eq 0 ]; then
unreachable=0
else
/usr/bin/logger -p local7.notice -t "NET" "dhclient: failed to create host route for unreachable router $router not on subnet $mySubnet";
fi
else
unreachable=1
if [ -x /usr/bin/logger ]; then
/usr/bin/logger -p local7.notice -t "NET" "dhclient: DHCP router $router is unreachable on DHCP subnet $mySubnet router subnet $routerSubnet";
fi;
fi;
fi;
return $unreachable;
}
function add_default_gateway()
{
router=$1
metric=''
if [ $# -gt 1 ] && [ "$2" -gt 0 ]; then
metric="metric $2";
fi;
if routerReachable $router ; then
/sbin/ip route replace default via $router dev $interface $metric;
if [ $? -ne 0 ]; then
/usr/bin/logger -p local7.notice -t "NET" 'dhclient: failed to create default route: '$router dev $interface $metric;
return 1;
else
return 0;
fi;
fi;
return 1;
}
function dhconfig()
{
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 2 ) != 2 )); then
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 $interface inet 0 down
fi
fi
if [ x$reason = xBOUND ] || [ x$reason = xREBOOT ] ||
[ x$old_ip_address != x$new_ip_address ] ||
[ x$old_subnet_mask != x$new_subnet_mask ] ||
[ x$new_network_number != x$new_network_number ] ||
[ x$old_broadcast_address != x$new_broadcast_address ] ||
[ "x$old_routers" != "x$new_routers" ] ||
[ x$old_interface_mtu != x$new_interface_mtu ] ; then
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 2 ) != 2 )); then
ifconfig $interface inet $new_ip_address $new_subnet_arg \
$new_broadcast_arg
if [ -n "$new_interface_mtu" ]; then
/sbin/ip link set $interface mtu $new_interface_mtu;
fi;
if [ -x /etc/dhclient-${interface}-up-hooks ]; then
. /etc/dhclient-${interface}-up-hooks;
elif [ -x /etc/dhclient-up-hooks ]; then
. /etc/dhclient-up-hooks;
fi;
fi;
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 4 ) != 4 )); then
prefix_bits=`mask_bits $new_subnet_mask`
# Add a network route to the computed network address.
if [ $relmajor -lt 2 ] || \
( [ $relmajor -eq 2 ] && [ $relminor -eq 0 ] ); then
/sbin/ip route replace ${new_network_number}/${prefix_bits} dev $interface
if [ $added_old_broadcast_route -eq 1 ]; then
/sbin/ip route del default;
fi;
fi;
if [[ ( ( -z "$GATEWAYDEV" ) || ( "$GATEWAYDEV" = "$interface" ) ) && ( ( -z "$GATEWAY" ) || ( ( -n "$DHCLIENT_IGNORE_GATEWAY" ) && ( "$DHCLIENT_IGNORE_GATEWAY" = [Yy]* ) ) ) ]]; then
metric=${METRIC:-''};
let i=${METRIC:-0};
default_routers=()
for router in $new_routers; do
added_router=0
for r in ${default_routers[@]}; do
if [ "$r" == "$router" ]; then
added_router=1;
fi;
done
if [ -z "$router" ] || [ "$added_router" -eq 1 ] || [ `IFS=. ip2num $router` -le 0 ] || [[ ( "$router" = "$new_broadcast_address" ) && ( "$new_subnet_mask" != "255.255.255.255" ) ]]; then
continue;
fi;
default_routers=(${default_routers[@]} $router)
add_default_gateway $router $metric;
let i=i+1;
metric=$i;
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
/sbin/ip route replace default via $GATEWAY dev $interface
fi;
fi;
# static routes
if [ "x$new_static_routes" != x ]; then
IFS=', ' static_routes=($new_static_routes)
route_targets=()
for((i=0; i<${#static_routes[@]}; i+=2)); do
target=${static_routes[$i]}
gateway=${static_routes[$i+1]}
metric=''
for t in ${route_targets[@]}; do
if [ $t == $target ]; then
if [ -z "$metric" ]; then
metric=1;
else
((metric=metric+1));
fi;
fi;
done;
if [ -n "$metric" ]; then
metric="metric $metric";
fi;
if routerReachable $gateway; then
/sbin/ip route replace ${target}/`class_bits $target` via ${gateway} dev $interface ${metric}
if [ $? -ne 0 ]; then
/usr/bin/logger -p local7.notice -t 'NET' 'dhclient: failed to create static route:' ${target}/`class_bits $target` via ${gateway} dev $interface ${metric};
else
route_targets=(${route_targets[@]} $target);
fi;
fi;
done
fi
fi
fi
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 2 ) != 2 )); then
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
/sbin/ip route replace ${alias_ip_address}/32 dev $interface:0
fi
fi
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 1 ) != 1 )); then
make_resolv_conf
if [ -n "$new_host_name" ] && need_hostname; then
hostname $new_host_name
fi
fi;
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 8 ) != 8 )); then
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##*\ }
if [ "$level" = "unknown" ]; then
level=1;
fi
if [ $contents -gt 0 ] && [[ "$level" = [0-6] ]] && /sbin/chkconfig --level=$level ypbind >/dev/null 2>&1 && [ -r /var/run/ypbind.pid ] && yppid=`cat /var/run/ypbind.pid` && [ -d /proc/${yppid} ] && [ "`if [ -x /sbin/busybox ]; then /sbin/busybox readlink /proc/${yppid}/exe; else echo /sbin/ypbind; fi`" = "/sbin/ypbind" ]; then
kill -HUP $yppid;
fi
elif [ -n "$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##*\ }
if [ "$level" = "unknown" ]; then
level=1;
fi
if [ $contents -gt 0 ] && [[ "$level" = [0-6] ]] && /sbin/chkconfig --level=$level ypbind >/dev/null 2>&1 && [ -r /var/run/ypbind.pid ] && yppid=`cat /var/run/ypbind.pid` && [ -d /proc/${yppid} ] && [ "`if [ -x /sbin/busybox ]; then /sbin/busybox readlink /proc/${yppid}/exe; else echo /sbin/ypbind; fi`" = "/sbin/ypbind" ] ; then
kill -HUP $yppid;
fi
fi
fi
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 16 ) != 16 )); then
if [ -n "$DHCP_TIME_OFFSET_SETS_TIMEZONE" ] && [[ "$DHCP_TIME_OFFSET_SETS_TIMEZONE" = [yY1]* ]]; then
if [ -n "$new_time_offset" ]; then
# DHCP option "time-offset" is requested by default and should be handled.
# The geographical zone abbreviation cannot be determined from the GMT offset,
# but the $ZONEINFO/Etc/GMT$offset file can be used - note: this disables DST.
((z=new_time_offset/3600));
((hoursWest=`printf '%+d' $z`))
if (( $hoursWest < 0 )); then
# tzdata treats negative 'hours west' as positive 'gmtoff' !
((hoursWest*=-1));
fi
tzfile=/usr/share/zoneinfo/Etc/GMT`printf '%+d' $hoursWest`;
if [ -e $tzfile ]; then
/bin/mv -f /etc/localtime /etc/localtime.predhclient;
/bin/cp -fp $tzfile /etc/localtime;
/bin/touch /etc/localtime;
fi;
fi;
fi;
if [ "${PEERNTP}" = no ]; then
:
elif [ -n "$new_ntp_servers" ] && [ -e /etc/ntp.conf ]; then
save_previous /etc/ntp.conf
/bin/egrep -v '^server .* # added by /sbin/dhclient-script$'< /etc/ntp.conf.predhclient > /etc/ntp.conf
for s in $new_ntp_servers; do
echo "server $s # added by /sbin/dhclient-script" >> /etc/ntp.conf;
done
if [ -x /usr/bin/diff ] && /usr/bin/diff -q /etc/ntp.conf /etc/ntp.conf.predhclient >/dev/null 2>&1; then
: ;
else
/sbin/service ntpd condrestart >/dev/null 2>&1
fi;
fi
fi;
}
if [ x$new_broadcast_address != x ] && [ x$new_subnet_mask != x ] && [ "$new_subnet_mask" != "255.255.255.255" ]; 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$reason = xPREINIT ]; then
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 2 ) != 2 )); 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.
/sbin/ip route replace default dev $interface && added_old_broadcast_route=1;
else
ifconfig $interface 0 up
fi
# We need to give the kernel some time to get the interface up.
# sleep 1
# I don't think this is necessary with modern kernels - no problems found during testing -
# JVD, 2005-06-17
# but just in case:
if [ -n "$DHCLIENT_DELAY" ] && [ "$DHCLIENT_DELAY" -gt 0 ] ; then
sleep $DHCLIENT_DELAY;
fi;
exit_with_hooks 0
fi;
fi
if [ x$reason = xARPCHECK ] || [ x$reason = xARPSEND ]; then
if [ -z "$new_ip_address" ] || [ -z "$interface" ] || /sbin/arping -q -f -c 2 -w 3 -D -I ${interface} ${new_ip_address}; then
exit_with_hooks 0
else
exit_with_hooks 1
fi;
fi
if [ x$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$reason = xSTOP ]; then
if [ -f /etc/resolv.conf.predhclient ]; then
change_resolv_conf /etc/resolv.conf.predhclient
rm -f /etc/resolv.conf.predhclient
fi
if [ -n "$DHCP_TIME_OFFSET_SETS_TIMEZONE" ] && [[ "$DHCP_TIME_OFFSET_SETS_TIMEZONE" = [yY1]* ]]; then
if [ -e /etc/localtime.predhclient ]; then
/bin/rm -f /etc/localtime
/bin/mv -f /etc/localtime.predhclient /etc/localtime;
/bin/touch /etc/localtime;
fi;
fi;
if [ -f /etc/ntp.conf.predhclient ]; then
/bin/rm -f /etc/ntp.conf
/bin/mv -f /etc/ntp.conf.predhclient /etc/ntp.conf
service ntpd condrestart >/dev/null 2>&1
fi
if [ -f /etc/yp.conf.predhclient ]; then
/bin/rm -f /etc/yp.conf
/bin/mv -f /etc/yp.conf.predhclient /etc/yp.conf
level=`/sbin/runlevel`
level=${level##*\ }
if [ "$level" = "unknown" ]; then
level=1;
fi
if [[ "$level" = [0-6] ]] && /sbin/chkconfig --level=$level ypbind >/dev/null 2>&1 && [ -r /var/run/ypbind.pid ] && yppid=`cat /var/run/ypbind.pid` && [ -d /proc/${yppid} ] && [ "`if [ -x /sbin/busybox ]; then /sbin/busybox readlink /proc/${yppid}/exe; else echo /sbin/ypbind; fi`" = "/sbin/ypbind" ] ; then
kill -HUP $yppid;
fi
fi
if [ -x /etc/dhclient-${interface}-down-hooks ]; then
. /etc/dhclient-${interface}-down-hooks;
elif [ -x /etc/dhclient-down-hooks ]; then
. /etc/dhclient-down-hooks;
fi;
if [ x$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
/sbin/ip route replace ${alias_ip_address}/32 $interface:0
fi
exit_with_hooks 0
fi
if [ x$reason = xTIMEOUT ] && [ "x$new_routers" != 'x' ]; then
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 2 ) != 2 )); 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
fi;
set $new_routers
if ping -q -c 1 -w 10 -I $interface $1; then
dhconfig ;
exit_with_hooks 0
fi
if [ -z "${dhc_dbus}" ] || (( ( dhc_dbus & 2 ) != 2 )); then
ifconfig $interface inet 0 down
fi;
exit_with_hooks 1
elif [ x$reason = xTIMEOUT ]; then
exit_with_hooks 1
fi
exit_with_hooks 0