--- /dev/null
+#!/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.
+
+# 4. TIMEOUT not tested. ping has a flag I don't know, and I'm suspicious
+# of the $1 in its args.
+
+# 5. Script refresh in 2017. The aliasing code was too convoluted and needs
+# to go away. Migrated DHCPv4 script to ip command from iproute2 suite.
+# This is based on Debian script with some tweaks. ifconfig is no longer
+# used. Everything is done using ip tool from ip-route2.
+
+# 6. LXC Fork
+# Remove hooks and dependency on ifconfig.
+# Resolve every paths against the $ROOTFS environment variable.
+
+# 'ip' just looks too weird. Also, we now have unit-tests! Those unit-tests
+# overwirte this line to use a fake ip-echo tool. It's also convenient
+# if your system holds ip tool in a non-standard location.
+ip=/sbin/ip
+
+# update /etc/resolv.conf based on received values
+# This updated version mostly follows Debian script by Andrew Pollock et al.
+make_resolv_conf() {
+ local resolv_conf="${ROOTFS}/etc/resolv.conf"
+ local new_resolv_conf="${ROOTFS}/etc/resolv.conf.dhclient-new"
+
+ # DHCPv4
+ if [ -n "$new_domain_search" ] || [ -n "$new_domain_name" ] ||
+ [ -n "$new_domain_name_servers" ]; then
+ 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
+ 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 $resolv_conf
+ fi
+}
+
+# set host name
+set_hostname() {
+ local current_hostname
+
+ if [ -n "$new_host_name" ]; then
+ 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 [ "$new_host_name" != "$old_host_name" ]; then
+ hostname "$new_host_name"
+ fi
+ fi
+ fi
+}
+
+# Execute the operation
+case "$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 2
+ fi
+
+ ;;
+
+ ### DHCPv6 Handlers
+ # TODO handle prefix change: ?based on ${old_ip6_prefix} and ${new_ip6_prefix}?
+
+ PREINIT6)
+ # ensure interface is up
+ ${ip} link set ${interface} up
+
+ # We need to give the kernel some time to active interface
+ interface_up_wait_time=5
+ for i in $(seq 0 ${interface_up_wait_time})
+ do
+ ${ip} addr show ${interface} | grep NO-CARRIER >/dev/null 2>&1
+ if [ $? -ne 0 ]; then
+ break;
+ fi
+ sleep 1
+ done
+
+ # flush any stale global permanent IPs from interface
+ ${ip} -6 addr flush dev ${interface} scope global permanent
+
+ # Wait for duplicate address detection for this interface if the
+ # --dad-wait-time parameter has been specified and is greater than
+ # zero.
+ if [ ${dad_wait_time} -gt 0 ]; then
+ # Check if any IPv6 address on this interface is marked as
+ # tentative.
+ ${ip} addr show ${interface} | grep inet6 | grep tentative \
+ &> /dev/null
+ if [ $? -eq 0 ]; then
+ # Wait for duplicate address detection to complete or for
+ # the timeout specified as --dad-wait-time.
+ for i in $(seq 0 $dad_wait_time)
+ do
+ # We're going to poll for the tentative flag every second.
+ sleep 1
+ ${ip} addr show ${interface} | grep inet6 | grep tentative \
+ &> /dev/null
+ if [ $? -ne 0 ]; then
+ break;
+ fi
+ done
+ fi
+ fi
+
+ ;;
+
+ BOUND6|RENEW6|REBIND6)
+ if [ "${new_ip6_address}" ] && [ "${new_ip6_prefixlen}" ]; then
+ # set leased IP
+ ${ip} -6 addr add ${new_ip6_address}/${new_ip6_prefixlen} \
+ 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)
+ if [ -z "${cur_ip6_prefixlen}" ]; then
+ exit 2
+ fi
+
+ # set preferred lifetime of leased IP to 0
+ ${ip} -6 addr change ${cur_ip6_address}/${cur_ip6_prefixlen} \
+ dev ${interface} scope global preferred_lft 0
+
+ ;;
+
+ EXPIRE6|RELEASE6|STOP6)
+ if [ -z "${old_ip6_address}" ] || [ -z "${old_ip6_prefixlen}" ]; then
+ exit 2
+ fi
+
+ # delete leased IP
+ ${ip} -6 addr del ${old_ip6_address}/${old_ip6_prefixlen} \
+ dev ${interface}
+
+ ;;
+esac
+
+exit 0
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