#!/bin/sh # Explicitly set the PATH to that of ENV_SUPATH in /etc/login.defs and unset # various other variables. We need to do this so /sbin/dhclient cannot abuse # the environment to escape AppArmor confinement via this script # (LP: #1045986). This can be removed once AppArmor supports environment # filtering (LP: #1045985) export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin export ENV= export BASH_ENV= export CDPATH= export GLOBIGNORE= export BASH_XTRACEFD= # dhclient-script for Linux. Dan Halbert, March, 1997. # Updated for Linux 2.[12] by Brian J. Murrell, January 1999. # Modified for Debian. Matt Zimmerman and Eloy Paris, December 2003 # Modified to remove useless tests for antiquated kernel versions that # this doesn't even work with anyway, and introduces a dependency on /usr # being mounted, which causes cosmetic errors on hosts that NFS mount /usr # Andrew Pollock, February 2005 # Modified to work on point-to-point links. Andrew Pollock, June 2005 # Modified to support passing the parameters called with to the hooks. Andrew Pollock, November 2005 # The alias handling in here probably still sucks. -mdz # log an error. error() { logger -p daemon.err "$@"; } # wait for given file to be writable wait_for_rw() { local file=$1 # Find out whether we are going to mount / rw exec 9>&0 </etc/fstab rootmode=rw while read dev mnt type opts dump pass junk; do [ "$mnt" != / ] && continue case "$opts" in ro|ro,*|*,ro|*,ro,*) rootmode=ro ;; esac done exec 0>&9 9>&- # Wait for $file to become writable if [ "$rootmode" = "rw" ]; then while ! { : >> "$file"; } 2>/dev/null; do sleep 0.1 done fi } # update /etc/resolv.conf based on received values make_resolv_conf() { local new_resolv_conf # DHCPv4 if [ -n "$new_domain_search" ] || [ -n "$new_domain_name" ] || [ -n "$new_domain_name_servers" ]; then resolv_conf=$(readlink -f "/etc/resolv.conf" 2>/dev/null) || resolv_conf="/etc/resolv.conf" new_resolv_conf="${resolv_conf}.dhclient-new.$$" wait_for_rw "$new_resolv_conf" rm -f $new_resolv_conf if [ -n "$new_domain_name" ]; then echo domain ${new_domain_name%% *} >>$new_resolv_conf fi if [ -n "$new_domain_search" ]; then if [ -n "$new_domain_name" ]; then domain_in_search_list="" for domain in $new_domain_search; do if [ "$domain" = "${new_domain_name}" ] || [ "$domain" = "${new_domain_name}." ]; then domain_in_search_list="Yes" fi done if [ -z "$domain_in_search_list" ]; then new_domain_search="$new_domain_name $new_domain_search" fi fi echo "search ${new_domain_search}" >> $new_resolv_conf elif [ -n "$new_domain_name" ]; then echo "search ${new_domain_name}" >> $new_resolv_conf fi if [ -n "$new_domain_name_servers" ]; then for nameserver in $new_domain_name_servers; do echo nameserver $nameserver >>$new_resolv_conf done else # keep 'old' nameservers sed -n /^\w*[Nn][Aa][Mm][Ee][Ss][Ee][Rr][Vv][Ee][Rr]/p $resolv_conf >>$new_resolv_conf fi if [ -f $resolv_conf ]; then chown --reference=$resolv_conf $new_resolv_conf chmod --reference=$resolv_conf $new_resolv_conf fi mv -f $new_resolv_conf $resolv_conf # DHCPv6 elif [ -n "$new_dhcp6_domain_search" ] || [ -n "$new_dhcp6_name_servers" ]; then resolv_conf=$(readlink -f "/etc/resolv.conf" 2>/dev/null) || resolv_conf="/etc/resolv.conf" new_resolv_conf="${resolv_conf}.dhclient-new.$$" wait_for_rw "$new_resolv_conf" rm -f $new_resolv_conf if [ -n "$new_dhcp6_domain_search" ]; then echo "search ${new_dhcp6_domain_search}" >> $new_resolv_conf fi if [ -n "$new_dhcp6_name_servers" ]; then for nameserver in $new_dhcp6_name_servers; do # append %interface to link-local-address nameservers if [ "${nameserver##fe80::}" != "$nameserver" ] || [ "${nameserver##FE80::}" != "$nameserver" ]; then nameserver="${nameserver}%${interface}" fi echo nameserver $nameserver >>$new_resolv_conf done else # keep 'old' nameservers sed -n /^\w*[Nn][Aa][Mm][Ee][Ss][Ee][Rr][Vv][Ee][Rr]/p $resolv_conf >>$new_resolv_conf fi if [ -f $resolv_conf ]; then chown --reference=$resolv_conf $new_resolv_conf chmod --reference=$resolv_conf $new_resolv_conf fi mv -f $new_resolv_conf $resolv_conf fi } # set host name set_hostname() { if [ -n "$new_host_name" ]; then local current_hostname=$(hostname) # current host name is empty, '(none)' or 'localhost' or differs from new one from DHCP if [ -z "$current_hostname" ] || [ "$current_hostname" = '(none)' ] || [ "$current_hostname" = 'localhost' ] || [ "$current_hostname" = "$old_host_name" ]; then if [ "$new_host_name" != "$current_host_name" ]; then hostname "$new_host_name" fi fi fi } # set the link up and wait for ipv6 link local dad to finish ipv6_link_up_and_dad() { local dev=$1 delay=${2:-0.1} attempts=${3:-60} ip link set up dev "$dev" || { error "$dev: failed to set link up"; return 1; } local n=0 while :; do n=$((n+1)) # note: busybox ip does not understand 'tentative' as input # so we cannot just use the tentative flag and check for empty out=$(ip -6 -o address show dev "$dev" scope link) || { error "$dev: checking for link-local addresses failed"; return 1 } # another note: the output may be empty if the link local tentative addr # isn't up just yet, so we need to make sure there is at least one 'inet6' # match before returning success. We need to keep checking for both # 'tentative' case and default (no inet6 address) case. (LP: #1718568) # Don't reorder tentative/inet6 - we need to check for tentative first. case " $out " in *\ dadfailed\ *) error "$dev: ipv6 dad failed." return 1;; *\ tentative\ *) :;; *\ inet6\ *) return 0;; *) :;; esac [ $n -lt $attempts ] || { error "$dev: time out waiting for permanent link-local address" return 1; } sleep $delay done } # run given script run_hook() { local script="$1" local exit_status=0 if [ -f $script ]; then . $script exit_status=$? fi if [ -n "$exit_status" ] && [ "$exit_status" -ne 0 ]; then logger -p daemon.err "$script returned non-zero exit status $exit_status" fi return $exit_status } # run scripts in given directory run_hookdir() { local dir="$1" local exit_status=0 if [ -d "$dir" ]; then for script in $(run-parts --list $dir); do run_hook $script exit_status=$((exit_status|$?)) done fi return $exit_status } # Must be used on exit. Invokes the local dhcp client exit hooks, if any. exit_with_hooks() { local exit_status=$1 # Source the documented exit-hook script, if it exists if ! run_hook /etc/dhcp/dhclient-exit-hooks; then exit_status=$? fi # Now run scripts in the Debian-specific directory. if ! run_hookdir /etc/dhcp/dhclient-exit-hooks.d; then exit_status=$? fi exit $exit_status } # The 576 MTU is only used for X.25 and dialup connections # where the admin wants low latency. Such a low MTU can cause # problems with UDP traffic, among other things. As such, # disallow MTUs from 576 and below by default, so that broken # MTUs are ignored, but higher stuff is allowed (1492, 1500, etc). if [ -z "$new_interface_mtu" ] || [ "$new_interface_mtu" -le 576 ]; then new_interface_mtu='' fi # The action starts here # Invoke the local dhcp client enter hooks, if they exist. run_hook /etc/dhcp/dhclient-enter-hooks run_hookdir /etc/dhcp/dhclient-enter-hooks.d # Execute the operation case "$reason" in ### DHCPv4 Handlers MEDIUM|ARPCHECK|ARPSEND) # Do nothing ;; PREINIT) # The DHCP client is requesting that an interface be # configured as required in order to send packets prior to # receiving an actual address. - dhclient-script(8) # ensure interface is up ip link set dev ${interface} up if [ -n "$alias_ip_address" ]; then # flush alias IP from interface ip -4 addr flush dev ${interface} label ${interface}:0 fi ;; BOUND|RENEW|REBIND|REBOOT) set_hostname if [ -n "$old_ip_address" ] && [ -n "$alias_ip_address" ] && [ "$alias_ip_address" != "$old_ip_address" ]; then # alias IP may have changed => flush it ip -4 addr flush dev ${interface} label ${interface}:0 fi if [ -n "$old_ip_address" ] && [ "$old_ip_address" != "$new_ip_address" ]; then # leased IP has changed => flush it ip -4 addr flush dev ${interface} label ${interface} fi if [ -z "$old_ip_address" ] || [ "$old_ip_address" != "$new_ip_address" ] || [ "$reason" = "BOUND" ] || [ "$reason" = "REBOOT" ]; then # new IP has been leased or leased IP changed => set it ip -4 addr add ${new_ip_address}${new_subnet_mask:+/$new_subnet_mask} \ ${new_broadcast_address:+broadcast $new_broadcast_address} \ dev ${interface} label ${interface} if [ -n "$new_interface_mtu" ]; then # set MTU ip link set dev ${interface} mtu ${new_interface_mtu} fi # if we have $new_rfc3442_classless_static_routes then we have to # ignore $new_routers entirely if [ ! "$new_rfc3442_classless_static_routes" ]; then # set if_metric if IF_METRIC is set or there's more than one router if_metric="$IF_METRIC" if [ "${new_routers%% *}" != "${new_routers}" ]; then if_metric=${if_metric:-1} fi for router in $new_routers; do if [ "$new_subnet_mask" = "255.255.255.255" ]; then # point-to-point connection => set explicit route ip -4 route add ${router} dev $interface >/dev/null 2>&1 fi # set default route ip -4 route add default via ${router} dev ${interface} \ ${if_metric:+metric $if_metric} >/dev/null 2>&1 if [ -n "$if_metric" ]; then if_metric=$((if_metric+1)) fi done fi fi if [ -n "$alias_ip_address" ] && [ "$new_ip_address" != "$alias_ip_address" ]; then # separate alias IP given, which may have changed # => flush it, set it & add host route to it ip -4 addr flush dev ${interface} label ${interface}:0 ip -4 addr add ${alias_ip_address}${alias_subnet_mask:+/$alias_subnet_mask} \ dev ${interface} label ${interface}:0 ip -4 route add ${alias_ip_address} dev ${interface} >/dev/null 2>&1 fi # update /etc/resolv.conf make_resolv_conf ;; EXPIRE|FAIL|RELEASE|STOP) if [ -n "$alias_ip_address" ]; then # flush alias IP ip -4 addr flush dev ${interface} label ${interface}:0 fi if [ -n "$old_ip_address" ]; then # flush leased IP ip -4 addr flush dev ${interface} label ${interface} fi if [ -n "$alias_ip_address" ]; then # alias IP given => set it & add host route to it ip -4 addr add ${alias_ip_address}${alias_subnet_mask:+/$alias_subnet_mask} \ dev ${interface} label ${interface}:0 ip -4 route add ${alias_ip_address} dev ${interface} >/dev/null 2>&1 fi ;; TIMEOUT) if [ -n "$alias_ip_address" ]; then # flush alias IP ip -4 addr flush dev ${interface} label ${interface}:0 fi # set IP from recorded lease ip -4 addr add ${new_ip_address}${new_subnet_mask:+/$new_subnet_mask} \ ${new_broadcast_address:+broadcast $new_broadcast_address} \ dev ${interface} label ${interface} if [ -n "$new_interface_mtu" ]; then # set MTU ip link set dev ${interface} mtu ${new_interface_mtu} fi # if there is no router recorded in the lease or the 1st router answers pings if [ -z "$new_routers" ] || ping -q -c 1 "${new_routers%% *}"; then # if we have $new_rfc3442_classless_static_routes then we have to # ignore $new_routers entirely if [ ! "$new_rfc3442_classless_static_routes" ]; then if [ -n "$alias_ip_address" ] && [ "$new_ip_address" != "$alias_ip_address" ]; then # separate alias IP given => set up the alias IP & add host route to it ip -4 addr add ${alias_ip_address}${alias_subnet_mask:+/$alias_subnet_mask} \ dev ${interface} label ${interface}:0 ip -4 route add ${alias_ip_address} dev ${interface} >/dev/null 2>&1 fi # set if_metric if IF_METRIC is set or there's more than one router if_metric="$IF_METRIC" if [ "${new_routers%% *}" != "${new_routers}" ]; then if_metric=${if_metric:-1} fi # set default route for router in $new_routers; do ip -4 route add default via ${router} dev ${interface} \ ${if_metric:+metric $if_metric} >/dev/null 2>&1 if [ -n "$if_metric" ]; then if_metric=$((if_metric+1)) fi done fi # update /etc/resolv.conf make_resolv_conf else # flush all IPs from interface ip -4 addr flush dev ${interface} exit_with_hooks 2 fi ;; ### DHCPv6 Handlers # TODO handle prefix change: ?based on ${old_ip6_prefix} and ${new_ip6_prefix}? PREINIT6) # ensure interface is up ipv6_link_up_and_dad "$interface" # flush any stale global permanent IPs from interface ip -6 addr flush dev ${interface} scope global permanent ;; BOUND6|RENEW6|REBIND6) if [ "${new_ip6_address}" ]; then # set leased IP ip -6 addr add ${new_ip6_address} \ dev ${interface} scope global fi # update /etc/resolv.conf if [ "${reason}" = BOUND6 ] || [ "${new_dhcp6_name_servers}" != "${old_dhcp6_name_servers}" ] || [ "${new_dhcp6_domain_search}" != "${old_dhcp6_domain_search}" ]; then make_resolv_conf fi ;; DEPREF6) # set preferred lifetime of leased IP to 0 ip -6 addr change ${cur_ip6_address} \ dev ${interface} scope global preferred_lft 0 ;; EXPIRE6|RELEASE6|STOP6) if [ -z "${old_ip6_address}" ]; then exit_with_hooks 2 fi # delete leased IP ip -6 addr del ${old_ip6_address} \ dev ${interface} ;; esac exit_with_hooks 0