Merge pull request #1932 from 3XX0/dhclient-hook

.gitignore

@@ -136,6 +136,8 @@ doc/manpage.refs
 doc/api/html/*
 
 hooks/unmount-namespace
+hooks/dhclient-start
+hooks/dhclient-stop
 
 m4/
 

configure.ac

@@ -889,6 +889,8 @@ AC_CONFIG_FILES([
 	doc/ko/see_also.sgml
 
 	hooks/Makefile
+	hooks/dhclient-start
+	hooks/dhclient-stop
 
 	templates/Makefile
 	templates/lxc-alpine

hooks/Makefile.am

@@ -5,6 +5,9 @@ hooks_SCRIPTS = \
 	clonehostname \
 	mountecryptfsroot \
 	ubuntu-cloud-prep \
+	dhclient-script \
+	dhclient-start \
+	dhclient-stop \
 	squid-deb-proxy-client
 
 binhooks_PROGRAMS = \

hooks/dhclient-script

+#!/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

hooks/dhclient-start.in

+#! /bin/bash
+
+set -e
+
+LXC_HOOK_DIR="@LXCHOOKDIR@"
+
+rootfs="${LXC_ROOTFS_PATH##*:}"
+pidfile="${rootfs%/*}/dhclient.pid"
+
+mkdir -p "${rootfs}/var/lib/dhclient"
+
+nsenter -u -U -n -t "${LXC_PID}" -- \
+  /sbin/dhclient -nw -1 -pf ${pidfile} -lf ${rootfs}/var/lib/dhclient/dhclient.leases -e ROOTFS=${rootfs} -sf ${LXC_HOOK_DIR}/dhclient-script

hooks/dhclient-stop.in

+#! /bin/bash
+
+set -e
+
+LXC_HOOK_DIR="@LXCHOOKDIR@"
+
+rootfs="${LXC_ROOTFS_PATH##*:}"
+pidfile="${rootfs%/*}/dhclient.pid"
+
+# XXX Stop hook namespace arguments are wrong for some reason, those are the host namespaces not the container ones.
+# Retrieve the namespaces from the dhclient pidfile instead.
+nsenter -u -U -n -t $(< ${pidfile}) -- \
+  /sbin/dhclient -r -pf ${pidfile} -lf ${rootfs}/var/lib/dhclient/dhclient.leases -e ROOTFS=${rootfs} -sf ${LXC_HOOK_DIR}/dhclient-script
+
+rm -f ${pidfile}