#!/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.

#

# Modified by David Cantrell <dcantrell@redhat.com> for Fedora and RHEL

# 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.

PATH=/bin:/usr/bin

function save_previous() {

    if [ -e $1 ]; then

        mv $1 $1.predhclient.$interface

    else

        echo ''> $1.predhclient.$interface

    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.$interface

        rscf=`mktemp /tmp/XXXXXX`;

        echo '; generated by /sbin/dhclient-script' > $rscf

        if [ -n "$new_domain_search" ]; then

            echo "search ${new_domain_search//\\032/ }" >> $rscf

        else

            if [ -n "$new_domain_name" ]; then

                echo "search ${new_domain_name//\\032/ }" >> $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 | cut -f1 -d'.')

relminor=$(echo $release | 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 [ 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$reason = xBOUND ] || [ x$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

        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

        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

    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

    make_resolv_conf

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

        hostname $new_host_name

    fi

    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

        if [ $contents -gt 0 ] && [ -r /var/run/ypbind.pid ] && yppid=$(cat /var/run/ypbind.pid) && [ -d /proc/${yppid} ] && [ "$(if [ -x /usr/bin/readlink ]; then 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

        if [ $contents -gt 0 ] && [ -r /var/run/ypbind.pid ] && yppid=$(cat /var/run/ypbind.pid) && [ -d /proc/${yppid} ] && [ "$(if [ -x /usr/bin/readlink ]; then readlink /proc/${yppid}/exe; else echo /sbin/ypbind; fi)" = "/sbin/ypbind" ]; then

            kill -HUP $yppid

        fi

    fi

    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.$interface

                /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$'< /etc/ntp.conf.predhclient.$interface > /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.$interface >/dev/null 2>&1; then

            :

        else

            /sbin/service ntpd condrestart >/dev/null 2>&1

        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 [ 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

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

    # only restore config files if there are no other dhclient processes

    # running (#306381)

    any_other_clients="$(/bin/ps -eo pid,ppid,comm | /bin/grep dhclient | /bin/grep -v $PPID)"

    if [ -n "$any_other_clients" ]; then

        if [ -f /etc/resolv.conf.predhclient.$interface ]; then

            change_resolv_conf /etc/resolv.conf.predhclient.$interface

            rm -f /etc/resolv.conf.predhclient.$interface

        fi

        if [ -n "$DHCP_TIME_OFFSET_SETS_TIMEZONE" ] && [[ "$DHCP_TIME_OFFSET_SETS_TIMEZONE" = [yY1]* ]]; then

            if [ -e /etc/localtime.predhclient.$interface ]; then

                /bin/rm -f /etc/localtime

                /bin/mv -f /etc/localtime.predhclient.$interface /etc/localtime

                /bin/touch /etc/localtime

            fi

        fi

        if [ -f /etc/ntp.conf.predhclient.$interface ]; then

            /bin/rm -f /etc/ntp.conf

            /bin/mv -f /etc/ntp.conf.predhclient.$interface /etc/ntp.conf

            service ntpd condrestart >/dev/null 2>&1

        fi

        if [ -f /etc/yp.conf.predhclient.$interface ]; then

            /bin/rm -f /etc/yp.conf

            /bin/mv -f /etc/yp.conf.predhclient.$interface /etc/yp.conf

            if [ -r /var/run/ypbind.pid ] && yppid=$(cat /var/run/ypbind.pid) && [ -d /proc/${yppid} ] && [ "$(if [ -x /usr/bin/readlink ]; then readlink /proc/${yppid}/exe; else echo /sbin/ypbind; fi)" = "/sbin/ypbind" ]; then

               kill -HUP $yppid

            fi

        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 [ 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

    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