#!/bin/bash # # dhclient-script: Network interface configuration script run by # dhclient based on DHCP client communication # # Copyright (C) 2008, 2009, 2010 Red Hat, Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . # # Author(s): David Cantrell # # ---------- # This script is a rewrite/reworking on dhclient-script originally # included as part of dhcp-970306: # dhclient-script for Linux. Dan Halbert, March, 1997. # Updated for Linux 2.[12] by Brian J. Murrell, January 1999. # Modified by David Cantrell for Fedora and RHEL # ---------- # PATH=/bin:/usr/bin:/sbin LOGFACILITY="local7" LOGLEVEL="notice" ETCDIR="/etc/dhcp" logmessage() { msg="${1}" logger -p ${LOGFACILITY}.${LOGLEVEL} -t "NET" "dhclient: ${msg}" } if [ -x /sbin/restorecon ]; then fix_context() { /sbin/restorecon ${1} >/dev/null 2>&1 } else fix_context() { :; } fi eventually_add_hostnames_domain_to_search() { # For the case when hostname for this machine has a domain that is not in domain_search list # 1) get a hostname with `ipcalc --hostname` or `hostname` # 2) get the domain from this hostname # 3) add this domain to search line in resolv.conf if it's not already # there (domain list that we have recently added there is a parameter of this function) # We can't do this directly when generating resolv.conf in make_resolv_conf(), because # we need to first save the resolv.conf with obtained values before we can call `ipcalc --hostname`. # See bug 637763 search="${1}" if need_hostname; then status=1 if [ -n "${new_ip_address}" ]; then eval $(/bin/ipcalc --silent --hostname ${new_ip_address} ; echo "status=$?") elif [ -n "${new_ip6_address}" ]; then eval $(/bin/ipcalc --silent --hostname ${new_ip6_address} ; echo "status=$?") fi if [ ${status} -eq 0 ]; then domain=$(echo $HOSTNAME | cut -s -d "." -f 2-) fi else domain=$(hostname 2>/dev/null | cut -s -d "." -f 2-) fi if [ -n "${domain}" ] && [ ! "${domain}" = "localdomain" ] && [ ! "${domain}" = "localdomain6" ] && [ ! "${domain}" = "(none)" ] && [[ ! "${domain}" = *\ * ]]; then is_in="false" for s in ${search}; do if [ "${s}" = "${domain}" ] || [ "${s}" = "${domain}." ]; then is_in="true" fi done if [ "${is_in}" = "false" ]; then # Add domain name to search list (#637763) sed -i -e "s/${search}/${search} ${domain}/" /etc/resolv.conf fi fi } make_resolv_conf() { [ "${PEERDNS}" = "no" ] && return if [ "${reason}" = "RENEW" ] && [ "${new_domain_name}" = "${old_domain_name}" ] && [ "${new_domain_name_servers}" = "${old_domain_name_servers}" ]; then return fi if [ -n "${new_domain_name}" ] || [ -n "${new_domain_name_servers}" ] || [ -n "${new_domain_search}" ]; then rscf="$(mktemp ${TMPDIR:-/tmp}/XXXXXX)" echo "; generated by /sbin/dhclient-script" > ${rscf} if [ -n "${SEARCH}" ]; then search="${SEARCH}" else if [ -n "${new_domain_search}" ]; then # Remove instaces of \032 (#450042) search="${new_domain_search//\\032/ }" elif [ -n "${new_domain_name}" ]; then # Note that the DHCP 'Domain Name Option' is really just a domain # name, and that this practice of using the domain name option as # a search path is both nonstandard and deprecated. search="${new_domain_name}" fi fi if [ -n "${search}" ]; then echo "search ${search}" >> $rscf fi if [ -n "${RES_OPTIONS}" ]; then echo "options ${RES_OPTIONS}" >> ${rscf} fi for nameserver in ${new_domain_name_servers} ; do echo "nameserver ${nameserver}" >> ${rscf} done change_resolv_conf ${rscf} rm -f ${rscf} if [ -n "${search}" ]; then eventually_add_hostnames_domain_to_search "${search}" fi fix_context /etc/resolv.conf elif [ -n "${new_dhcp6_name_servers}" ] || [ -n "${new_dhcp6_domain_search}" ]; then rscf="$(mktemp ${TMPDIR:-/tmp}/XXXXXX)" echo "; generated by /sbin/dhclient-script" > ${rscf} if [ -n "${SEARCH}" ]; then search="${SEARCH}" else if [ -n "${new_dhcp6_domain_search}" ]; then search="${new_dhcp6_domain_search//\\032/ }" fi fi if [ -n "${search}" ]; then echo "search ${search}" >> $rscf fi if [ -n "${RES_OPTIONS}" ]; then echo "options ${RES_OPTIONS}" >> ${rscf} fi shopt -s nocasematch for nameserver in ${new_dhcp6_name_servers} ; do # If the nameserver has a link-local address # add a (interface name) to it. if [[ "$nameserver" =~ ^fe80:: ]] then zone_id="%${interface}" else zone_id= fi echo "nameserver ${nameserver}$zone_id" >> ${rscf} done shopt -u nocasematch change_resolv_conf ${rscf} rm -f ${rscf} if [ -n "${search}" ]; then eventually_add_hostnames_domain_to_search "${search}" fi fix_context /etc/resolv.conf fi } exit_with_hooks() { exit_status="${1}" if [ -x ${ETCDIR}/dhclient-exit-hooks ]; then . ${ETCDIR}/dhclient-exit-hooks fi exit ${exit_status} } quad2num() { if [ $# -eq 4 ]; then let n="${1} << 24 | ${2} << 16 | ${3} << 8 | ${4}" echo "${n}" return 0 else echo "0" return 1 fi } ip2num() { IFS="." quad2num ${1} } num2ip() { let n="${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}" } get_network_address() { # get network address for the given IP address and (netmask or prefix) ip="${1}" nm="${2}" if [ -n "${ip}" -a -n "${nm}" ]; then if [[ "${nm}" = *.* ]]; then ipcalc -s -n ${ip} ${nm} | cut -d '=' -f 2 else ipcalc -s -n ${ip}/${nm} | cut -d '=' -f 2 fi fi } get_prefix() { # get prefix for the given IP address and mask ip="${1}" nm="${2}" if [ -n "${ip}" -a -n "${nm}" ]; then ipcalc -s -p ${ip} ${nm} | cut -d '=' -f 2 fi } class_bits() { let ip=$(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 $bits } is_router_reachable() { # handle DHCP servers that give us a router not on our subnet router="${1}" routersubnet="$(get_network_address ${router} ${new_subnet_mask})" mysubnet="$(get_network_address ${new_ip_address} ${new_subnet_mask})" if [ ! "${routersubnet}" = "${mysubnet}" ]; then ip -4 route add ${router}/32 dev ${interface} if [ $? -eq 0 ]; then if ping -q -c1 -w2 -I ${interface} ${router}; then return 0 else logmessage "DHCP router ${router} is unreachable on DHCP subnet ${mysubnet} router subnet ${routersubnet}" ip route del ${router}/32 dev ${interface} return 1 fi else logmessage "failed to create host router for unreachable router ${router} not on subnet ${mysubnet}" return 1 fi fi return 0 } add_default_gateway() { router="${1}" if is_router_reachable ${router} ; then metric="" if [ $# -gt 1 ] && [ ${2} -gt 0 ]; then metric="metric ${2}" fi ip -4 route replace default via ${router} dev ${interface} ${metric} if [ $? -ne 0 ]; then logmessage "failed to create default route: ${router} dev ${interface} ${metric}" return 1 else return 0 fi fi return 1 } execute_client_side_configuration_scripts() { # execute any additional client side configuration scripts we have if [ "${1}" == "config" ] || [ "${1}" == "restore" ]; then for f in ${ETCDIR}/dhclient.d/*.sh ; do if [ -x ${f} ]; then subsystem="${f%.sh}" subsystem="${subsystem##*/}" . ${f} "${subsystem}_${1}" fi done fi } flush_dev() { # Instead of bringing the interface down (#574568) # explicitly clear the ARP cache and flush all addresses & routes. ip -4 addr flush dev ${1} >/dev/null 2>&1 ip -4 route flush dev ${1} >/dev/null 2>&1 ip -4 neigh flush dev ${1} >/dev/null 2>&1 } dhconfig() { if [ -n "${old_ip_address}" ] && [ -n "${alias_ip_address}" ] && [ ! "${alias_ip_address}" = "${old_ip_address}" ]; then # possible new alias, remove old alias first ip -4 addr del ${old_ip_address} dev ${interface} label ${interface}:0 fi if [ -n "${old_ip_address}" ] && [ ! "${old_ip_address}" = "${new_ip_address}" ]; then # IP address changed. Delete all routes, and clear the ARP cache. flush_dev ${interface} fi if [ "${reason}" = "BOUND" ] || [ "${reason}" = "REBOOT" ] || [ ! "${old_ip_address}" = "${new_ip_address}" ] || [ ! "${old_subnet_mask}" = "${new_subnet_mask}" ] || [ ! "${old_network_number}" = "${new_network_number}" ] || [ ! "${old_broadcast_address}" = "${new_broadcast_address}" ] || [ ! "${old_routers}" = "${new_routers}" ] || [ ! "${old_interface_mtu}" = "${new_interface_mtu}" ]; then ip -4 addr add ${new_ip_address}/${new_prefix} broadcast ${new_broadcast_address} dev ${interface} ip link set dev ${interface} up # The 576 MTU is only used for X.25 and dialup connections # where the admin wants low latency. Such a low MTU can cause # problems with UDP traffic, among other things. As such, # disallow MTUs from 576 and below by default, so that broken # MTUs are ignored, but higher stuff is allowed (1492, 1500, etc). if [ -n "${new_interface_mtu}" ] && [ ${new_interface_mtu} -gt 576 ]; then ip link set ${interface} mtu ${new_interface_mtu} fi if [ -x ${ETCDIR}/dhclient-${interface}-up-hooks ]; then . ${ETCDIR}/dhclient-${interface}-up-hooks elif [ -x ${ETCDIR}/dhclient-up-hooks ]; then . ${ETCDIR}/dhclient-up-hooks fi # static routes if [ -n "${new_classless_static_routes}" ] || [ -n "${new_static_routes}" ]; then if [ -n "${new_classless_static_routes}" ]; then IFS=', |' static_routes=(${new_classless_static_routes}) else IFS=', |' static_routes=(${new_static_routes}) fi route_targets=() for((i=0; i<${#static_routes[@]}; i+=2)); do target=${static_routes[$i]} if [ -n "${new_classless_static_routes}" ]; then if [ ${target} = "0" ]; then # If the DHCP server returns both a Classless Static Routes option and # a Router option, the DHCP client MUST ignore the Router option. (RFC3442) new_routers="" prefix="0" else prefix=${target%%.*} target=${target#*.} IFS="." target_arr=(${target}) unset IFS ((pads=4-${#target_arr[@]})) for j in $(seq $pads); do target="${target}.0" done # Client MUST zero any bits in the subnet number where the corresponding bit in the mask is zero. # In other words, the subnet number installed in the routing table is the logical AND of # the subnet number and subnet mask given in the Classless Static Routes option. (RFC3442) target="$(get_network_address ${target} ${prefix})" fi else prefix=$(class_bits ${target}) fi gateway=${static_routes[$i+1]} # special case 0.0.0.0 to allow static routing for link-local addresses # (including IPv4 multicast) which will not have a next-hop (#769463, #787318) if [ "${gateway}" = "0.0.0.0" ]; then valid_gateway=0 scope='scope link' else is_router_reachable ${gateway} valid_gateway=$? scope='' fi if [ ${valid_gateway} -eq 0 ]; then 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 ip -4 route replace ${target}/${prefix} proto static via ${gateway} dev ${interface} ${metric} ${scope} if [ $? -ne 0 ]; then logmessage "failed to create static route: ${target}/${prefix} via ${gateway} dev ${interface} ${metric}" else route_targets=(${route_targets[@]} ${target}) fi fi done fi # gateways if [[ ( "${DEFROUTE}" != "no" ) && (( -z "${GATEWAYDEV}" ) || ( "${GATEWAYDEV}" = "${interface}" )) ]]; then if [[ ( -z "$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=- for r in ${default_routers[@]} ; do if [ "${r}" = "${router}" ]; then added_router=1 fi done if [ -z "${router}" ] || [ "${added_router}" = "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 [ -n "${GATEWAY}" ]; then routersubnet=$(get_network_address ${GATEWAY} ${new_subnet_mask}) mysubnet=$(get_network_address ${new_ip_address} ${new_subnet_mask}) if [ "${routersubnet}" = "${mysubnet}" ]; then ip -4 route replace default via ${GATEWAY} dev ${interface} fi fi fi fi if [ ! "${new_ip_address}" = "${alias_ip_address}" ] && [ -n "${alias_ip_address}" ]; then # Reset the alias address (fix: this should really only do this on changes) ip -4 addr flush dev ${interface} label ${interface}:0 >/dev/null 2>&1 ip -4 addr add ${alias_ip_address}/${alias_prefix} broadcast ${alias_broadcast_address} dev ${interface} label ${interface}:0 ip -4 route replace ${alias_ip_address}/32 dev ${interface} fi make_resolv_conf if [ -n "${new_host_name}" ] && need_hostname; then hostname ${new_host_name} || echo "See -nc option in dhclient(8) man page." fi if [[ ( "${DHCP_TIME_OFFSET_SETS_TIMEZONE}" = [yY1]* ) && ( -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 cp -fp ${tzfile} /etc/localtime touch /etc/localtime fix_context /etc/localtime fi fi execute_client_side_configuration_scripts "config" } # Section 18.1.8. (Receipt of Reply Messages) of RFC 3315 says: # The client SHOULD perform duplicate address detection on each of # the addresses in any IAs it receives in the Reply message before # using that address for traffic. add_ipv6_addr_with_DAD() { ip -6 addr add ${new_ip6_address}/${new_ip6_prefixlen} \ dev ${interface} scope global # repeatedly test whether newly added address passed # duplicate address detection (DAD) for i in $(seq 5); do sleep 1 # give the DAD some time # tentative flag == DAD is still not complete tentative=$(ip -6 addr show dev ${interface} tentative \ | grep ${new_ip6_address}/${new_ip6_prefixlen}) # dadfailed flag == address is already in use somewhere else dadfailed=$(ip -6 addr show dev ${interface} dadfailed \ | grep ${new_ip6_address}/${new_ip6_prefixlen}) if [ -n "${dadfailed}" ] ; then #ip -6 addr del ${new_ip6_address}/${new_ip6_prefixlen} dev ${interface} exit_with_hooks 3 fi if [ -z "${tentative}" ] ; then # DAD is over return 0 fi done } dh6config() { if [ -n "${old_ip6_prefix}" ] || [ -n "${new_ip6_prefix}" ]; then echo Prefix ${reason} old=${old_ip6_prefix} new=${new_ip6_prefix} exit_with_hooks 0 fi case "${reason}" in BOUND6) if [ -z "${new_ip6_address}" ] || [ -z "${new_ip6_prefixlen}" ]; then exit_with_hooks 2 fi add_ipv6_addr_with_DAD make_resolv_conf ;; RENEW6|REBIND6) if [ -z "${new_ip6_address}" ] || [ -z "${new_ip6_prefixlen}" ]; then exit_with_hooks 2 fi if [ ! "${new_ip6_address}" = "${old_ip6_address}" ]; then add_ipv6_addr_with_DAD fi if [ ! "${new_dhcp6_name_servers}" = "${old_dhcp6_name_servers}" ] || [ ! "${new_dhcp6_domain_search}" = "${old_dhcp6_domain_search}" ]; then make_resolv_conf fi ;; DEPREF6) if [ -z "${new_ip6_prefixlen}" ]; then exit_with_hooks 2 fi ip -6 addr change ${new_ip6_address}/${new_ip6_prefixlen} \ dev ${interface} scope global preferred_lft 0 ;; esac execute_client_side_configuration_scripts "config" } # # ### MAIN # if [ -x ${ETCDIR}/dhclient-enter-hooks ]; then exit_status=0 # dhclient-enter-hooks can abort dhclient-script by setting # the exit_status variable to a non-zero value . ${ETCDIR}/dhclient-enter-hooks if [ ${exit_status} -ne 0 ]; then exit ${exit_status} fi fi if [ ! -r /etc/sysconfig/network-scripts/network-functions ]; then echo "Missing /etc/sysconfig/network-scripts/network-functions, exiting." >&2 exit 1 fi if [ ! -r /etc/rc.d/init.d/functions ]; then echo "Missing /etc/rc.d/init.d/functions, exiting." >&2 exit 1 fi . /etc/sysconfig/network-scripts/network-functions . /etc/rc.d/init.d/functions if [ -f /etc/sysconfig/network ]; then . /etc/sysconfig/network fi if [ -f /etc/sysconfig/networking/network ]; then . /etc/sysconfig/networking/network fi cd /etc/sysconfig/network-scripts CONFIG="ifcfg-${interface}" need_config ${CONFIG} source_config >/dev/null 2>&1 new_prefix="$(get_prefix ${new_ip_address} ${new_subnet_mask})" old_prefix="$(get_prefix ${old_ip_address} ${old_subnet_mask})" alias_prefix="$(get_prefix ${alias_ip_address} ${alias_subnet_mask})" case "${reason}" in MEDIUM|ARPCHECK|ARPSEND) # Do nothing exit_with_hooks 0 ;; PREINIT) if [ -n "${alias_ip_address}" ]; then # Flush alias, its routes will disappear too. ip -4 addr flush dev ${interface} label ${interface}:0 >/dev/null 2>&1 fi if [ "${keep_old_ip}" = "yes" ]; then ip link set ${interface} up else ip -4 addr flush dev ${interface} >/dev/null 2>&1 ip link set ${interface} up fi if [ -n "${DHCLIENT_DELAY}" ] && [ ${DHCLIENT_DELAY} -gt 0 ]; then sleep ${DHCLIENT_DELAY} fi exit_with_hooks 0 ;; PREINIT6) # ensure interface is up ip link set ${interface} up # remove any stale addresses from aborted clients ip -6 addr flush dev ${interface} scope global permanent exit_with_hooks 0 ;; BOUND|RENEW|REBIND|REBOOT) if [ -z "${interface}" ] || [ -z "${new_ip_address}" ]; then exit_with_hooks 2 fi if arping -D -q -c2 -I ${interface} ${new_ip_address}; then dhconfig exit_with_hooks 0 else # DAD failed, i.e. address is already in use exit_with_hooks 1 fi ;; BOUND6|RENEW6|REBIND6|DEPREF6) dh6config exit_with_hooks 0 ;; EXPIRE6|RELEASE6|STOP6) if [ -z "${old_ip6_address}" ] || [ -z "${old_ip6_prefixlen}" ]; then exit_with_hooks 2 fi ip -6 addr del ${old_ip6_address}/${old_ip6_prefixlen} \ dev ${interface} execute_client_side_configuration_scripts "restore" if [ -x ${ETCDIR}/dhclient-${interface}-down-hooks ]; then . ${ETCDIR}/dhclient-${interface}-down-hooks elif [ -x ${ETCDIR}/dhclient-down-hooks ]; then . ${ETCDIR}/dhclient-down-hooks fi exit_with_hooks 0 ;; EXPIRE|FAIL|RELEASE|STOP) execute_client_side_configuration_scripts "restore" if [ -x ${ETCDIR}/dhclient-${interface}-down-hooks ]; then . ${ETCDIR}/dhclient-${interface}-down-hooks elif [ -x ${ETCDIR}/dhclient-down-hooks ]; then . ${ETCDIR}/dhclient-down-hooks fi if [ -n "${alias_ip_address}" ]; then # Flush alias ip -4 addr flush dev ${interface} label ${interface}:0 >/dev/null 2>&1 fi if [ -n "${old_ip_address}" ]; then # Delete addresses/routes/arp cache. flush_dev ${interface} fi if [ -n "${alias_ip_address}" ]; then ip -4 addr add ${alias_ip_address}/${alias_prefix} broadcast ${alias_broadcast_address} dev ${interface} label ${interface}:0 ip -4 route replace ${alias_ip_address}/32 dev ${interface} fi exit_with_hooks 0 ;; TIMEOUT) if [ -n "${new_routers}" ]; then if [ -n "${alias_ip_address}" ]; then ip -4 addr flush dev ${interface} label ${interface}:0 >/dev/null 2>&1 fi ip -4 addr add ${new_ip_address}/${new_prefix} broadcast ${new_broadcast_address} dev ${interface} set ${new_routers} if ping -q -c 1 -w 10 -I ${interface} ${1}; then dhconfig exit_with_hooks 0 fi flush_dev ${interface} exit_with_hooks 1 else exit_with_hooks 1 fi ;; *) logmessage "unhandled state: ${reason}" exit_with_hooks 1 ;; esac exit_with_hooks 0