#!/bin/sh # 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. # 4. TIMEOUT not tested. ping has a flag I don't know, and I'm suspicious # of the $1 in its args. # Must be used on exit. Invokes the local dhcp client exit hooks, if any. function exit_with_hooks() { exit_status=$1 if [ -x /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 [ -x /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 release=`uname -r` release=`expr $release : '\(.*\)\..*'` relmajor=`echo $release |sed -e 's/^\([^\.]*\)\..*$/\1/'` relminor=`echo $release |sed -e 's/^.*\.\([^\.]*\)$/\1/'` if [ x$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 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 [ $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 else ifconfig $interface up fi # We need to give the kernel some time to get the interface up. sleep 1 exit_with_hooks 0 fi if [ x$reason = xARPCHECK ] || [ x$reason = xARPSEND ]; then exit_with_hooks 0 fi if [ x$reason = xBOUND ] || [ x$reason = xRENEW ] || \ [ x$reason = xREBIND ] || [ x$reason = xREBOOT ]; then if [ x$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 $interface inet down fi if [ x$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 fi for router in $new_routers; do route add default gw $router done fi if [ x$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 echo search $new_domain_name >/etc/resolv.conf for nameserver in $new_domain_name_servers; do echo nameserver $nameserver >>/etc/resolv.conf done exit_with_hooks 0 fi if [ x$reason = xEXPIRE ] || [ x$reason = xFAIL ]; then if [ x$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 $interface inet down fi if [ x$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 ]; 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 ############## what is -w in ping? if ping -q -c 1 $1; then if [ x$new_ip_address != x$alias_ip_address ] && \ [ x$alias_ip_address != x ]; then ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg route add -host $alias_ip_address dev $interface:0 fi if [ $relmajor -lt 2 ] || \ ( [ $relmajor -eq 2 ] && [ $relminor -eq 0 ] ); then route add -net $new_network_number fi for router in $new_routers; do route add default gw $router done echo search $new_domain_name >/etc/resolv.conf.std for nameserver in $new_domain_name_servers; do echo nameserver $nameserver >>/etc/resolv.conf.std done if [ -f /etc/resolv.conf ]; then rm -f /etc/resolv.conf ln /etc/resolv.conf.std /etc/resolv.conf fi exit_with_hooks 0 fi ifconfig $interface inet down exit_with_hooks 1 fi exit_with_hooks 0