utilities/ovs-lib.in

   1 # -*- sh -*-
   2 # vi:syntax=sh
   3 # This is a shell function library sourced by some Open vSwitch scripts.
   4 # It is not intended to be invoked on its own.
   5
   6 # Copyright (C) 2009, 2010, 2011, 2012 Nicira, Inc.
   7 #
   8 # Licensed under the Apache License, Version 2.0 (the "License");
   9 # you may not use this file except in compliance with the License.
  10 # You may obtain a copy of the License at:
  11 #
  12 #     http://www.apache.org/licenses/LICENSE-2.0
  13 #
  14 # Unless required by applicable law or agreed to in writing, software
  15 # distributed under the License is distributed on an "AS IS" BASIS,
  16 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17 # See the License for the specific language governing permissions and
  18 # limitations under the License.
  19
  20 ## ----------------- ##
  21 ## configure options ##
  22 ## ----------------- ##
  23
  24 # All of these should be substituted by the Makefile at build time.
  25 logdir=${OVS_LOGDIR-'@LOGDIR@'}                 # /var/log/openvswitch
  26 rundir=${OVS_RUNDIR-'@RUNDIR@'}                 # /var/run/openvswitch
  27 sysconfdir=${OVS_SYSCONFDIR-'@sysconfdir@'}     # /etc
  28 etcdir=$sysconfdir/openvswitch                  # /etc/openvswitch
  29 datadir=${OVS_PKGDATADIR-'@pkgdatadir@'}        # /usr/share/openvswitch
  30 bindir=${OVS_BINDIR-'@bindir@'}                 # /usr/bin
  31 sbindir=${OVS_SBINDIR-'@sbindir@'}              # /usr/sbin
  32
  33 # /etc/openvswitch or /var/lib/openvswitch
  34 if test X"$OVS_DBDIR" != X; then
  35     dbdir=$OVS_DBDIR
  36 elif test X"$OVS_SYSCONFDIR" != X; then
  37     dbdir=$OVS_SYSCONFDIR/openvswitch
  38 else
  39     dbdir='@DBDIR@'
  40 fi
  41
  42 ovs_ctl_log () {
  43     echo "$@" >> "${logdir}/ovs-ctl.log"
  44 }
  45
  46 ovs_ctl () {
  47     case "$@" in
  48         *"=strace"*)
  49             # In case of running the daemon with strace, piping the o/p causes
  50             # the script to block (strace probably does not close the inherited
  51             # pipe). So, do not log the o/p to ovs-ctl.log.
  52             "${datadir}/scripts/ovs-ctl" "$@"
  53         ;;
  54         "status")
  55             # In case of the command 'status', we should return the exit status
  56             # of ovs-ctl. It is also useful to document the o/p in ovs-ctl.log.
  57             display=`"${datadir}/scripts/ovs-ctl" "$@" 2>&1`
  58             rc=$?
  59             if test -w "${logdir}/ovs-ctl.log"; then
  60                  echo "${display}" | tee -a "${logdir}/ovs-ctl.log"
  61             else
  62                  echo "${display}"
  63             fi
  64             return ${rc}
  65         ;;
  66         *)
  67             echo "`date -u`:$@" >> "${logdir}/ovs-ctl.log"
  68             "${datadir}/scripts/ovs-ctl" "$@" 2>&1 | tee -a "${logdir}/ovs-ctl.log"
  69         ;;
  70     esac
  71 }
  72
  73 VERSION='@VERSION@'
  74
  75 DAEMON_CWD=/
  76
  77 LC_ALL=C; export LC_ALL
  78
  79 ## ------------- ##
  80 ## LSB functions ##
  81 ## ------------- ##
  82
  83 # Use the system's own implementations if it has any.
  84 if test -e /etc/init.d/functions; then
  85     . /etc/init.d/functions
  86 elif test -e /etc/rc.d/init.d/functions; then
  87     . /etc/rc.d/init.d/functions
  88 elif test -e /lib/lsb/init-functions; then
  89     . /lib/lsb/init-functions
  90 fi
  91
  92 # Implement missing functions (e.g. OpenSUSE lacks 'action').
  93 if type log_success_msg >/dev/null 2>&1; then :; else
  94     log_success_msg () {
  95         printf '%s.\n' "$*"
  96     }
  97 fi
  98 if type log_failure_msg >/dev/null 2>&1; then :; else
  99     log_failure_msg () {
 100         printf '%s ... failed!\n' "$*"
 101     }
 102 fi
 103 if type log_warning_msg >/dev/null 2>&1; then :; else
 104     log_warning_msg () {
 105         printf '%s ... (warning).\n' "$*"
 106     }
 107 fi
 108 if type action >/dev/null 2>&1; then :; else
 109     action () {
 110        STRING=$1
 111        shift
 112        "$@"
 113        rc=$?
 114        if test $rc = 0; then
 115             log_success_msg "$STRING"
 116        else
 117             log_failure_msg "$STRING"
 118        fi
 119        return $rc
 120     }
 121 fi
 122
 123 ## ------- ##
 124 ## Daemons ##
 125 ## ------- ##
 126
 127 pid_exists () {
 128     # This is better than "kill -0" because it doesn't require permission to
 129     # send a signal (so daemon_status in particular works as non-root).
 130     test -d /proc/"$1"
 131 }
 132
 133 pid_comm_check () {
 134     [ "$1" = "`cat /proc/$2/comm`" ]
 135 }
 136
 137 # version_geq version_a version_b
 138 #
 139 # Compare (dot separated) version numbers.  Returns true (exit code 0) if
 140 # version_a is greater or equal than version_b, otherwise false (exit code 1).
 141 version_geq() {
 142     echo $1 $2 | awk '{
 143         n1 = split($1, a, ".");
 144         n2 = split($2, b, ".");
 145         n = (n1 > n2) ? n1 : n2;
 146         for (i = 1; i <= n; i++) {
 147             if (a[i]+0 < b[i]+0) exit 1
 148             if (a[i]+0 > b[i]+0) exit 0
 149         }
 150     }'
 151 }
 152
 153 install_dir () {
 154     DIR="$1"
 155     INSTALL_MODE="${2:-755}"
 156     INSTALL_USER="root"
 157     INSTALL_GROUP="root"
 158     [ "$OVS_USER" != "" ] && INSTALL_USER="${OVS_USER%:*}"
 159     [ "${OVS_USER##*:}" != "" ] && INSTALL_GROUP="${OVS_USER##*:}"
 160
 161     if test ! -d "$DIR"; then
 162         install -d -m "$INSTALL_MODE" -o "$INSTALL_USER" -g "$INSTALL_GROUP" "$DIR"
 163         restorecon "$DIR" >/dev/null 2>&1
 164     fi
 165 }
 166
 167 start_daemon () {
 168     priority=$1
 169     wrapper=$2
 170     shift; shift
 171     daemon=$1
 172     strace=""
 173
 174     # drop core files in a sensible place
 175     install_dir "$DAEMON_CWD"
 176     set "$@" --no-chdir
 177     cd "$DAEMON_CWD"
 178
 179     # log file
 180     install_dir "$logdir" "750"
 181     set "$@" --log-file="$logdir/$daemon.log"
 182
 183     # pidfile and monitoring
 184     install_dir "$rundir"
 185     set "$@" --pidfile="$rundir/$daemon.pid"
 186     set "$@" --detach
 187     test X"$MONITOR" = Xno || set "$@" --monitor
 188
 189     # wrapper
 190     case $wrapper in
 191         valgrind)
 192             if (valgrind --version) > /dev/null 2>&1; then
 193                 set valgrind -q --leak-check=full --time-stamp=yes \
 194                     --log-file="$logdir/$daemon.valgrind.log.%p" "$@"
 195             else
 196                 log_failure_msg "valgrind not installed, running $daemon without it"
 197             fi
 198             ;;
 199         strace)
 200             if (strace -V) > /dev/null 2>&1; then
 201                 strace="strace -tt -T -s 256 -ff"
 202                 if (strace -DV) > /dev/null 2>&1; then
 203                     # Has the -D option.
 204                     set $strace -D -o "$logdir/$daemon.strace.log" "$@"
 205                     strace=""
 206                 fi
 207             else
 208                 log_failure_msg "strace not installed, running $daemon without it"
 209             fi
 210             ;;
 211         glibc)
 212             set env MALLOC_CHECK_=2 MALLOC_PERTURB_=165 "$@"
 213             ;;
 214         '')
 215             ;;
 216         *)
 217             log_failure_msg "unknown wrapper $wrapper, running $daemon without it"
 218             ;;
 219     esac
 220
 221     # priority
 222     if test X"$priority" != X; then
 223         set nice -n "$priority" "$@"
 224     fi
 225
 226     action "Starting $daemon" "$@" || return 1
 227
 228     if test X"$strace" != X; then
 229         # Strace doesn't have the -D option so we attach after the fact.
 230         setsid $strace -o "$logdir/$daemon.strace.log" \
 231             -p `cat $rundir/$daemon.pid` > /dev/null 2>&1 &
 232     fi
 233 }
 234
 235 stop_daemon () {
 236     if test -e "$rundir/$1.pid"; then
 237         if pid=`cat "$rundir/$1.pid"`; then
 238
 239             graceful="EXIT .1 .25 .65 1"
 240             actions="TERM .1 .25 .65 1 1 1 1 \
 241                      KILL 1 1 1 2 10 15 30 \
 242                      FAIL"
 243             version=`ovs-appctl -T 1 -t $rundir/$1.$pid.ctl version \
 244                      | awk 'NR==1{print $NF}'`
 245
 246             # Use `ovs-appctl exit` only if the running daemon version
 247             # is >= 2.5.90.  This script might be used during upgrade to
 248             # stop older versions of daemons which do not behave correctly
 249             # with `ovs-appctl exit` (e.g. ovs-vswitchd <= 2.5.0 deletes
 250             # internal ports).
 251             if version_geq "$version" "2.5.90"; then
 252                 actions="$graceful $actions"
 253             fi
 254             for action in $actions; do
 255                 if pid_exists "$pid" >/dev/null 2>&1; then :; else
 256                     return 0
 257                 fi
 258                 case $action in
 259                     EXIT)
 260                         action "Exiting $1 ($pid)" \
 261                             ${bindir}/ovs-appctl -T 1 -t $rundir/$1.$pid.ctl exit
 262                         ;;
 263                     TERM)
 264                         action "Killing $1 ($pid)" kill $pid
 265                         ;;
 266                     KILL)
 267                         action "Killing $1 ($pid) with SIGKILL" kill -9 $pid
 268                         ;;
 269                     FAIL)
 270                         log_failure_msg "Killing $1 ($pid) failed"
 271                         return 1
 272                         ;;
 273                     *)
 274                         sleep $action
 275                         ;;
 276                 esac
 277             done
 278         fi
 279     fi
 280     log_success_msg "$1 is not running"
 281 }
 282
 283 daemon_status () {
 284     pidfile=$rundir/$1.pid
 285     if test -e "$pidfile"; then
 286         if pid=`cat "$pidfile"`; then
 287             if pid_exists "$pid"; then
 288                 echo "$1 is running with pid $pid"
 289                 return 0
 290             else
 291                 echo "Pidfile for $1 ($pidfile) is stale"
 292             fi
 293         else
 294             echo "Pidfile for $1 ($pidfile) exists but cannot be read"
 295         fi
 296     else
 297         echo "$1 is not running"
 298     fi
 299     return 1
 300 }
 301
 302 daemon_is_running () {
 303     pidfile=$rundir/$1.pid
 304     test -e "$pidfile" && pid=`cat "$pidfile"` && pid_exists "$pid" && pid_comm_check $1 $pid
 305 } >/dev/null 2>&1
 306
 307 # Prints commands needed to move the ip address from interface $1 to interface
 308 # $2
 309 move_ip_address () {
 310     if [ -z "$1" ] || [ -z "$2" ]; then
 311         return
 312     fi
 313     dev="$1"
 314     dst="$2"
 315
 316     # IP addresses (including IPv6).
 317     echo "ip addr flush dev $dev 2>/dev/null" # Suppresses "Nothing to flush".
 318     ip addr show dev $dev | while read addr; do
 319         set -- $addr
 320
 321         # Check and trim family.
 322         family=$1
 323         shift
 324         case $family in
 325             inet | inet6) ;;
 326             *) continue ;;
 327         esac
 328
 329         # Trim device off the end--"ip" insists on having "dev" precede it.
 330         addrcmd=
 331         while test $# != 0; do
 332             case $1 in
 333                 dynamic)
 334                     # XXX: According to 'man ip-address', "dynamic" is only
 335                     # used for ipv6 addresses.  But, atleast on RHEL 7.4
 336                     # (iproute-3.10.0-87), it is being used for ipv4
 337                     # addresses assigned with dhcp.
 338                     if [ "$family" = "inet" ]; then
 339                         shift
 340                         continue
 341                     fi
 342                     # Omit kernel-maintained route.
 343                     continue 2
 344                     ;;
 345                 scope)
 346                     if test "$2" = link -a "$family" != inet6; then
 347                         # Omit route derived from IP address, e.g.
 348                         # 172.16.0.0/16 derived from 172.16.12.34,
 349                         # but preserve IPv6 link-local address.
 350                         continue 2
 351                     fi
 352                     ;;
 353                 "$dev"|"$dev:"*)
 354                     # Address label string
 355                     label=`echo $1 | sed "s/$dev/$dst/"`
 356                     addrcmd="$addrcmd label $label"
 357                     shift
 358                     continue
 359                     ;;
 360             esac
 361             addrcmd="$addrcmd $1"
 362             shift
 363         done
 364         if test "$1" != "$dev"; then
 365             addrcmd="$addrcmd $1"
 366         fi
 367
 368         echo ip -f $family addr add $addrcmd dev $dst
 369     done
 370 }
 371
 372 # Prints commands needed to move the ip route of interface $1 to interface $2
 373 move_ip_routes () {
 374     if [ -z "$1" ] || [ -z "$2" ]; then
 375         return
 376     fi
 377     dev="$1"
 378     dst="$2"
 379     echo "ip route flush dev $dev proto boot 2>/dev/null" # Suppresses "Nothing to flush".
 380     ip route show dev $dev | while read route; do
 381         # "proto kernel" routes are installed by the kernel automatically.
 382         case $route in
 383             *" proto kernel "*) continue ;;
 384         esac
 385
 386         echo "ip route add $route dev $dst"
 387     done
 388 }
 389
 390 ovsdb_tool () {
 391     if [ "$OVS_USER" != "" ]; then
 392         runuser --user "${OVS_USER%:*}" -- ovsdb-tool -vconsole:off "$@"
 393     else
 394         ovsdb-tool -vconsole:off "$@"
 395     fi
 396 }
 397
 398 create_db () {
 399     DB_FILE="$1"
 400     DB_SCHEMA="$2"
 401     action "Creating empty database $DB_FILE" ovsdb_tool create "$DB_FILE" "$DB_SCHEMA"
 402 }
 403
 404 backup_db () {
 405     # Back up the old version.
 406     version=`ovsdb_tool db-version "$DB_FILE"`
 407     cksum=`ovsdb_tool db-cksum "$DB_FILE" | awk '{print $1}'`
 408     backup=$DB_FILE.backup$version-$cksum
 409     action "Backing up database to $backup" cp "$DB_FILE" "$backup" || return 1
 410 }
 411
 412 upgrade_db () {
 413     DB_FILE="$1"
 414     DB_SCHEMA="$2"
 415
 416     schemaver=`ovsdb_tool schema-version "$DB_SCHEMA"`
 417     if test ! -e "$DB_FILE"; then
 418         log_warning_msg "$DB_FILE does not exist"
 419         install_dir `dirname $DB_FILE`
 420         create_db "$DB_FILE" "$DB_SCHEMA"
 421     elif test X"`ovsdb_tool needs-conversion "$DB_FILE" "$DB_SCHEMA"`" = Xyes; then
 422         backup_db || return 1
 423
 424         # Compact database.  This is important if the old schema did not enable
 425         # garbage collection (i.e. if it did not have any tables with "isRoot":
 426         # true) but the new schema does.  In that situation the old database
 427         # may contain a transaction that creates a record followed by a
 428         # transaction that creates the first use of the record.  Replaying that
 429         # series of transactions against the new database schema (as "convert"
 430         # does) would cause the record to be dropped by the first transaction,
 431         # then the second transaction would cause a referential integrity
 432         # failure (for a strong reference).
 433         #
 434         # Errors might occur on an Open vSwitch downgrade if ovsdb-tool doesn't
 435         # understand some feature of the schema used in the OVSDB version that
 436         # we're downgrading from, so we don't give up on error.
 437         action "Compacting database" ovsdb_tool compact "$DB_FILE"
 438
 439         # Upgrade or downgrade schema.
 440         if action "Converting database schema" ovsdb_tool convert "$DB_FILE" "$DB_SCHEMA"; then
 441             :
 442         else
 443             log_warning_msg "Schema conversion failed, using empty database instead"
 444             rm -f "$DB_FILE"
 445             create_db "$DB_FILE" "$DB_SCHEMA"
 446         fi
 447     fi
 448 }
 449
 450 upgrade_cluster () {
 451     local DB_SCHEMA=$1 DB_SERVER=$2
 452     local schema_name=$(ovsdb-tool schema-name $1) || return 1
 453
 454     action "Waiting for $schema_name to come up" ovsdb-client -t 30 wait "$DB_SERVER" "$schema_name" connected || return $?
 455     local db_version=$(ovsdb-client -t 10 get-schema-version "$DB_SERVER" "$schema_name") || return $?
 456     local target_version=$(ovsdb-tool schema-version "$DB_SCHEMA") || return $?
 457
 458     if ovsdb-tool compare-versions "$db_version" == "$target_version"; then
 459         :
 460     elif ovsdb-tool compare-versions "$db_version" ">" "$target_version"; then
 461         log_warning_msg "Database $schema_name has newer schema version ($db_version) than our local schema ($target_version), possibly an upgrade is partially complete?"
 462     else
 463         action "Upgrading database $schema_name from schema version $db_version to $target_version" ovsdb-client -t 30 convert "$DB_SERVER" "$DB_SCHEMA"
 464     fi
 465 }
 466
 467 create_cluster () {
 468     DB_FILE="$1"
 469     DB_SCHEMA="$2"
 470     LOCAL_ADDR="$3"
 471
 472     if test ! -e "$DB_FILE"; then
 473         action "Creating cluster database $DB_FILE" ovsdb_tool create-cluster "$DB_FILE" "$DB_SCHEMA" "$LOCAL_ADDR"
 474     elif ovsdb_tool db-is-standalone "$DB_FILE"; then
 475         # Convert standalone database to clustered.
 476         backup_db || return 1
 477         action "Creating cluster database $DB_FILE from existing one" \
 478                ovsdb_tool create-cluster "$DB_FILE" "$backup" "$LOCAL_ADDR"
 479     fi
 480 }
 481
 482 join_cluster() {
 483     DB_FILE="$1"
 484     SCHEMA_NAME="$2"
 485     LOCAL_ADDR="$3"
 486     REMOTE_ADDR="$4"
 487
 488     if test ! -e "$DB_FILE"; then
 489         ovsdb_tool join-cluster "$DB_FILE" "$SCHEMA_NAME" "$LOCAL_ADDR" "$REMOTE_ADDR"
 490     elif ovsdb_tool db-is-standalone "$DB_FILE"; then
 491         # Backup standalone database and join cluster.
 492         backup_db || return 1
 493         action "Joining $DB_FILE to cluster" \
 494                ovsdb_tool join-cluster "$DB_FILE" "$SCHEMA_NAME" "$LOCAL_ADDR"
 495     fi
 496 }
 497
 498 ovs_vsctl () {
 499     ovs-vsctl --no-wait "$@"
 500 }
 501
 502 ## ----------------- ##
 503 ## force-reload-kmod ##
 504 ## ----------------- ##
 505
 506 internal_interfaces () {
 507     # Outputs a list of internal interfaces:
 508     #
 509     #   - There is an internal interface for every bridge, whether it
 510     #     has an Interface record or not and whether the Interface
 511     #     record's 'type' is properly set or not.
 512     #
 513     #   - There is an internal interface for each Interface record whose
 514     #     'type' is 'internal'.
 515     #
 516     # But ignore interfaces that don't really exist.
 517     for d in `(ovs_vsctl --bare \
 518                 -- --columns=name find Interface type=internal \
 519                     -- list-br) | sort -u`
 520     do
 521         if test -e "/sys/class/net/$d"; then
 522                 printf "%s " "$d"
 523             fi
 524     done
 525 }
 526
 527 ovs_save () {
 528     bridges=`ovs_vsctl -- --real list-br`
 529     if [ -n "${bridges}" ] && \
 530         "$datadir/scripts/ovs-save" "$1" ${bridges} > "$2"; then
 531         chmod +x "$2"
 532         return 0
 533     fi
 534     [ -z "${bridges}" ] && return 0
 535 }
 536
 537 save_flows_if_required () {
 538     if test X"$DELETE_BRIDGES" != Xyes; then
 539         action "Saving flows" ovs_save save-flows "${script_flows}"
 540     fi
 541 }
 542
 543 save_interfaces () {
 544     "$datadir/scripts/ovs-save" save-interfaces ${ifaces} \
 545         > "${script_interfaces}"
 546 }
 547
 548 flow_restore_wait () {
 549     if test X"${OVS_VSWITCHD:-yes}" = Xyes; then
 550         ovs_vsctl set open_vswitch . other_config:flow-restore-wait="true"
 551     fi
 552 }
 553
 554 flow_restore_complete () {
 555     if test X"${OVS_VSWITCHD:-yes}" = Xyes; then
 556         ovs_vsctl --if-exists remove open_vswitch . other_config \
 557                   flow-restore-wait="true"
 558     fi
 559 }
 560
 561 restore_flows () {
 562     [ -x "${script_flows}" ] && \
 563         action "Restoring saved flows" "${script_flows}"
 564 }
 565
 566 restore_interfaces () {
 567     [ ! -x "${script_interfaces}" ] && return 0
 568     action "Restoring interface configuration" "${script_interfaces}"
 569     rc=$?
 570     if test $rc = 0; then
 571         level=debug
 572     else
 573         level=err
 574     fi
 575     log="logger -p daemon.$level -t ovs-save"
 576     $log "interface restore script exited with status $rc:"
 577     $log -f "$script_interfaces"
 578 }
 579
 580 init_restore_scripts () {
 581     script_interfaces=`mktemp`
 582     script_flows=`mktemp`
 583     trap 'rm -f "${script_interfaces}" "${script_flows}"' 0
 584 }
 585
 586 force_reload_kmod () {
 587
 588     if test X"${OVS_VSWITCHD:-yes}" != Xyes; then
 589         log_failure_msg "Reloading of kmod without ovs-vswitchd is an error"
 590         exit 1
 591     fi
 592
 593     ifaces=`internal_interfaces`
 594     action "Detected internal interfaces: $ifaces" true
 595
 596     init_restore_scripts
 597     save_flows_if_required
 598
 599     # Restart the database first, since a large database may take a
 600     # while to load, and we want to minimize forwarding disruption.
 601     stop_ovsdb
 602     start_ovsdb || return 1
 603
 604     stop_forwarding
 605
 606     if action "Saving interface configuration" save_interfaces; then
 607         :
 608     else
 609         log_warning_msg "Failed to save configuration, not replacing kernel module"
 610         start_forwarding
 611         add_managers
 612         exit 1
 613     fi
 614     chmod +x "$script_interfaces"
 615
 616     for dp in `ovs-dpctl dump-dps`; do
 617         action "Removing datapath: $dp" ovs-dpctl del-dp "$dp"
 618     done
 619     action "ovs-appctl dpctl/flush-conntrack"
 620
 621     for vport in `awk '/^vport_/ { print $1 }' /proc/modules`; do
 622         action "Removing $vport module" rmmod $vport
 623     done
 624
 625     if test -e /sys/module/openvswitch; then
 626         action "Removing openvswitch module" rmmod openvswitch
 627     fi
 628
 629     # Start vswitchd by asking it to wait till flow restore is finished.
 630     flow_restore_wait
 631     start_forwarding || return 1
 632
 633     # Restore saved flows and inform vswitchd that we are done.
 634     restore_flows
 635     flow_restore_complete
 636     add_managers
 637
 638     restore_interfaces
 639
 640     "$datadir/scripts/ovs-check-dead-ifs"
 641 }
 642
 643 ## ------- ##
 644 ## restart ##
 645 ## ------- ##
 646
 647 restart () {
 648     if daemon_is_running ovsdb-server && daemon_is_running ovs-vswitchd; then
 649         init_restore_scripts
 650         if test X"${OVS_VSWITCHD:-yes}" = Xyes; then
 651             save_flows_if_required
 652         fi
 653     fi
 654
 655     # Restart the database first, since a large database may take a
 656     # while to load, and we want to minimize forwarding disruption.
 657     stop_ovsdb
 658     start_ovsdb || return 1
 659
 660     stop_forwarding
 661
 662     # Start vswitchd by asking it to wait till flow restore is finished.
 663     flow_restore_wait
 664     start_forwarding || return 1
 665
 666     # Restore saved flows and inform vswitchd that we are done.
 667     restore_flows
 668     flow_restore_complete
 669     add_managers
 670 }