NAME | SYNOPSIS | DESCRIPTION | OPTIONS | RUNTIME MANAGEMENT COMMANDS | EXAMPLES | SEE ALSO | COLOPHON

ovs-ofctl(8)                 Open vSwitch Manual                ovs-ofctl(8)

NAME         top

       ovs-ofctl - administer OpenFlow switches

SYNOPSIS         top

       ovs-ofctl [options] command [switch] [args...]

DESCRIPTION         top

       The ovs-ofctl program is a command line tool for monitoring and
       administering OpenFlow switches.  It can also show the current state
       of an OpenFlow switch, including features, configuration, and table
       entries.  It should work with any OpenFlow switch, not just Open
       vSwitch.

   OpenFlow Switch Management Commands
       These commands allow ovs-ofctl to monitor and administer an OpenFlow
       switch.  It is able to show the current state of a switch, including
       features, configuration, and table entries.

       Most of these commands take an argument that specifies the method for
       connecting to an OpenFlow switch.  The following connection methods
       are supported:

              ssl:ip[:port]
              tcp:ip[:port]
                     The specified port on the host at the given ip, which
                     must be expressed as an IP address (not a DNS name) in
                     IPv4 or IPv6 address format.  Wrap IPv6 addresses in
                     square brackets, e.g. tcp:[::1]:6653.  On Linux, use
                     %device to designate a scope for IPv6 link-level
                     addresses, e.g. tcp:[fe80::1234%eth0]:6653.  For ssl,
                     the --private-key, --certificate, and --ca-cert options
                     are mandatory.

                     If port is not specified, it defaults to 6653.

              unix:file
                     On POSIX, a Unix domain server socket named file.

                     On Windows, connect to a local named pipe that is
                     represented by a file created in the path file to mimic
                     the behavior of a Unix domain socket.

              file   This is short for unix:file, as long as file does not
                     contain a colon.

              bridge This is short for
                     unix:/usr/local/var/run/openvswitch/bridge.mgmt, as
                     long as bridge does not contain a colon.

              [type@]dp
                     Attempts to look up the bridge associated with dp and
                     open as above.  If type is given, it specifies the
                     datapath provider of dp, otherwise the default provider
                     system is assumed.

       show switch
              Prints to the console information on switch, including
              information on its flow tables and ports.

       dump-tables switch
              Prints to the console statistics for each of the flow tables
              used by switch.

       dump-table-features switch
              Prints to the console features for each of the flow tables
              used by switch.

       dump-table-desc switch
              Prints to the console configuration for each of the flow
              tables used by switch for OpenFlow 1.4+.

       mod-table switch table_id setting
              This command configures flow table settings for OpenFlow table
              table_id within switch.  The available settings depend on the
              OpenFlow version in use.  In OpenFlow 1.1 and 1.2 (which must
              be enabled with the -O option) only, mod-table configures
              behavior when no flow is found when a packet is looked up in a
              flow table.  The following setting values are available:

              drop   Drop the packet.

              continue
                     Continue to the next table in the pipeline.  (This is
                     how an OpenFlow 1.0 switch always handles packets that
                     do not match any flow, in tables other than the last
                     one.)

              controller
                     Send to controller.  (This is how an OpenFlow 1.0
                     switch always handles packets that do not match any
                     flow in the last table.)

              In OpenFlow 1.4 and later (which must be enabled with the -O
              option) only, mod-table configures the behavior when a
              controller attempts to add a flow to a flow table that is
              full.  The following setting values are available:

              evict  Delete some existing flow from the flow table,
                     according to the algorithm described for the Flow_Table
                     table in ovs-vswitchd.conf.db(5).

              noevict
                     Refuse to add the new flow.  (Eviction might still be
                     enabled through the overflow_policy column in the
                     Flow_Table table documented in
                     ovs-vswitchd.conf.db(5).)

              vacancy:low,high
                     Enables sending vacancy events to controllers using
                     TABLE_STATUS messages, based on percentage thresholds
                     low and high.

              novacancy
                     Disables vacancy events.

       dump-ports switch [netdev]
              Prints to the console statistics for network devices
              associated with switch.  If netdev is specified, only the
              statistics associated with that device will be printed.
              netdev can be an OpenFlow assigned port number or device name,
              e.g. eth0.

       dump-ports-desc switch [port]
              Prints to the console detailed information about network
              devices associated with switch.  To dump only a specific port,
              specify its number as port.  Otherwise, if port is omitted, or
              if it is specified as ANY, then all ports are printed.  This
              is a subset of the information provided by the show command.

              If the connection to switch negotiates OpenFlow 1.0, 1.2, or
              1.2, this command uses an OpenFlow extension only implemented
              in Open vSwitch (version 1.7 and later).

              Only OpenFlow 1.5 and later support dumping a specific port.
              Earlier versions of OpenFlow always dump all ports.

       mod-port switch port action
              Modify characteristics of port port in switch.  port may be an
              OpenFlow port number or name (unless --no-names is specified)
              or the keyword LOCAL (the preferred way to refer to the
              OpenFlow local port).  The action may be any one of the
              following:
              up
              down   Enable or disable the interface.  This is equivalent to
                     ip link set up or ip link set down on a Unix system.

              stp
              no-stp Enable or disable 802.1D spanning tree protocol (STP)
                     on the interface.  OpenFlow implementations that don't
                     support STP will refuse to enable it.

              receive
              no-receive
              receive-stp
              no-receive-stp
                     Enable or disable OpenFlow processing of packets
                     received on this interface.  When packet processing is
                     disabled, packets will be dropped instead of being
                     processed through the OpenFlow table.  The receive or
                     no-receive setting applies to all packets except 802.1D
                     spanning tree packets, which are separately controlled
                     by receive-stp or no-receive-stp.

              forward
              no-forward
                     Allow or disallow forwarding of traffic to this
                     interface.  By default, forwarding is enabled.

              flood
              no-flood
                     Controls whether an OpenFlow flood action will send
                     traffic out this interface.  By default, flooding is
                     enabled.  Disabling flooding is primarily useful to
                     prevent loops when a spanning tree protocol is not in
                     use.

              packet-in
              no-packet-in
                     Controls whether packets received on this interface
                     that do not match a flow table entry generate a
                     ``packet in'' message to the OpenFlow controller.  By
                     default, ``packet in'' messages are enabled.

              The show command displays (among other information) the
              configuration that mod-port changes.

       get-frags switch
              Prints switch's fragment handling mode.  See set-frags, below,
              for a description of each fragment handling mode.

              The show command also prints the fragment handling mode among
              its other output.

       set-frags switch frag_mode
              Configures switch's treatment of IPv4 and IPv6 fragments.  The
              choices for frag_mode are:

              normal Fragments pass through the flow table like non-
                     fragmented packets.  The TCP ports, UDP ports, and ICMP
                     type and code fields are always set to 0, even for
                     fragments where that information would otherwise be
                     available (fragments with offset 0).  This is the
                     default fragment handling mode for an OpenFlow switch.

              drop   Fragments are dropped without passing through the flow
                     table.

              reassemble
                     The switch reassembles fragments into full IP packets
                     before passing them through the flow table.  Open
                     vSwitch does not implement this fragment handling mode.

              nx-match
                     Fragments pass through the flow table like non-
                     fragmented packets.  The TCP ports, UDP ports, and ICMP
                     type and code fields are available for matching for
                     fragments with offset 0, and set to 0 in fragments with
                     nonzero offset.  This mode is a Nicira extension.

              See the description of ip_frag, below, for a way to match on
              whether a packet is a fragment and on its fragment offset.

       dump-flows switch [flows]
              Prints to the console all flow entries in switch's tables that
              match flows.  If flows is omitted, all flows in the switch are
              retrieved.  See Flow Syntax, below, for the syntax of flows.
              The output format is described in Table Entry Output.

              By default, ovs-ofctl prints flow entries in the same order
              that the switch sends them, which is unlikely to be intuitive
              or consistent.  Use --sort and --rsort to control display
              order.  The --names/--no-names and --stats/--no-stats options
              also affect output formatting.  See the descriptions of these
              options, under OPTIONS below, for more information

       dump-aggregate switch [flows]
              Prints to the console aggregate statistics for flows in
              switch's tables that match flows.  If flows is omitted, the
              statistics are aggregated across all flows in the switch's
              flow tables.  See Flow Syntax, below, for the syntax of flows.
              The output format is described in Table Entry Output.

       queue-stats switch [port [queue]]
              Prints to the console statistics for the specified queue on
              port within switch.  port can be an OpenFlow port number or
              name, the keyword LOCAL (the preferred way to refer to the
              OpenFlow local port), or the keyword ALL.  Either of port or
              queue or both may be omitted (or equivalently the keyword
              ALL).  If both are omitted, statistics are printed for all
              queues on all ports.  If only queue is omitted, then
              statistics are printed for all queues on port; if only port is
              omitted, then statistics are printed for queue on every port
              where it exists.

       queue-get-config switch [port [queue]]
              Prints to the console the configuration of queue on port in
              switch.  If port is omitted or ANY, reports queues for all
              port.  If queue is omitted or ANY, reports all queues.  For
              OpenFlow 1.3 and earlier, the output always includes all
              queues, ignoring queue if specified.

              This command has limited usefulness, because ports often have
              no configured queues and because the OpenFlow protocol
              provides only very limited information about the configuration
              of a queue.

       dump-ipfix-bridge switch
              Prints to the console the statistics of bridge IPFIX for
              switch.  If bridge IPFIX is configured on the switch, IPFIX
              statistics can be retrieved.  Otherwise, error message will be
              printed.

              This command uses an Open vSwitch extension that is only in
              Open vSwitch 2.6 and later.

       dump-ipfix-flow switch
              Prints to the console the statistics of flow-based IPFIX for
              switch.  If flow-based IPFIX is configured on the switch,
              statistics of all the collector set ids on the switch will be
              printed.  Otherwise, print error message.

              Refer to ovs-vswitchd.conf.db(5) for more details on
              configuring flow based IPFIX and collector set ids.

              This command uses an Open vSwitch extension that is only in
              Open vSwitch 2.6 and later.

       ct-flush-zone switch zone
              Flushes the connection tracking entries in zone on switch.

              This command uses an Open vSwitch extension that is only in
              Open vSwitch 2.6 and later.

   OpenFlow 1.1+ Group Table Commands
       The following commands work only with switches that support OpenFlow
       1.1 or later.  Because support for OpenFlow 1.1 and later is still
       experimental in Open vSwitch, it is necessary to explicitly enable
       these protocol versions in ovs-ofctl (using -O) and in the switch
       itself (with the protocols column in the Bridge table).  For more
       information, see ``Q: What versions of OpenFlow does Open vSwitch
       support?'' in the Open vSwitch FAQ.

       dump-groups switch [group]
              Prints group entries in switch's tables to console.  To dump
              only a specific group, specify its number as group.
              Otherwise, if group is omitted, or if it is specified as ALL,
              then all groups are printed.  Each line of output is a group
              entry as described in Group Syntax below.

              Only OpenFlow 1.5 and later support dumping a specific group.
              Earlier versions of OpenFlow always dump all groups.

       dump-group-features switch
              Prints to the console the group features of the switch.

       dump-group-stats switch [groups]
              Prints to the console statistics for the specified groups in
              the switch's tables.  If groups is omitted then statistics for
              all groups are printed.  See Group Syntax, below, for the
              syntax of groups.

   OpenFlow 1.3+ Switch Meter Table Commands
       These commands manage the meter table in an OpenFlow switch.  In each
       case, meter specifies a meter entry in the format described in Meter
       Syntax, below.

       OpenFlow 1.3 introduced support for meters, so these commands only
       work with switches that support OpenFlow 1.3 or later.  The caveats
       described for groups in the previous section also apply to meters.

       add-meter switch meter
              Add a meter entry to switch's tables. The meter syntax is
              described in section Meter Syntax, below.

       mod-meter switch meter
              Modify an existing meter.

       del-meters switch
       del-meter switch [meter]
              Delete entries from switch's meter table.  meter can specify a
              single meter with syntax meter=id, or all meters with syntax
              meter=all.

       dump-meters switch
       dump-meter switch [meter]
              Print meter configuration.  meter can specify a single meter
              with syntax meter=id, or all meters with syntax meter=all.

       meter-stats switch [meter]
              Print meter statistics.  meter can specify a single meter with
              syntax meter=id, or all meters with syntax meter=all.

       meter-features switch
              Print meter features.

   OpenFlow Switch Flow Table Commands
       These commands manage the flow table in an OpenFlow switch.  In each
       case, flow specifies a flow entry in the format described in Flow
       Syntax, below, file is a text file that contains zero or more flows
       in the same syntax, one per line, and the optional --bundle option
       operates the command as a single atomic transation, see option
       --bundle, below.

       [--bundle] add-flow switch flow
       [--bundle] add-flow switch - < file
       [--bundle] add-flows switch file
              Add each flow entry to switch's tables.  Each flow
              specification (e.g., each line in file) may start with add,
              modify, delete, modify_strict, or delete_strict keyword to
              specify whether a flow is to be added, modified, or deleted,
              and whether the modify or delete is strict or not.  For
              backwards compatibility a flow specification without one of
              these keywords is treated as a flow add.  All flow mods are
              executed in the order specified.

       [--bundle] [--strict] mod-flows switch flow
       [--bundle] [--strict] mod-flows switch - < file
              Modify the actions in entries from switch's tables that match
              the specified flows.  With --strict, wildcards are not treated
              as active for matching purposes.

       [--bundle] del-flows switch
       [--bundle] [--strict] del-flows switch [flow]
       [--bundle] [--strict] del-flows switch - < file
              Deletes entries from switch's flow table.  With only a switch
              argument, deletes all flows.  Otherwise, deletes flow entries
              that match the specified flows.  With --strict, wildcards are
              not treated as active for matching purposes.

       [--bundle] [--readd] replace-flows switch file
              Reads flow entries from file (or stdin if file is -) and
              queries the flow table from switch.  Then it fixes up any
              differences, adding flows from flow that are missing on
              switch, deleting flows from switch that are not in file, and
              updating flows in switch whose actions, cookie, or timeouts
              differ in file.

              With --readd, ovs-ofctl adds all the flows from file, even
              those that exist with the same actions, cookie, and timeout in
              switch.  In OpenFlow 1.0 and 1.1, re-adding a flow always
              resets the flow's packet and byte counters to 0, and in
              OpenFlow 1.2 and later, it does so only if the reset_counts
              flag is set.

       diff-flows source1 source2
              Reads flow entries from source1 and source2 and prints the
              differences.  A flow that is in source1 but not in source2 is
              printed preceded by a -, and a flow that is in source2 but not
              in source1 is printed preceded by a +.  If a flow exists in
              both source1 and source2 with different actions, cookie, or
              timeouts, then both versions are printed preceded by - and +,
              respectively.

              source1 and source2 may each name a file or a switch.  If a
              name begins with / or ., then it is considered to be a file
              name.  A name that contains : is considered to be a switch.
              Otherwise, it is a file if a file by that name exists, a
              switch if not.

              For this command, an exit status of 0 means that no
              differences were found, 1 means that an error occurred, and 2
              means that some differences were found.

       packet-out switch packet-out
              Connects to switch and instructs it to execute the packet-out
              OpenFlow message, specified as defined in Packet-Out Syntax
              section.

   OpenFlow Switch Group Table Commands
       These commands manage the group table in an OpenFlow switch.  In each
       case, group specifies a group entry in the format described in Group
       Syntax, below, and file is a text file that contains zero or more
       groups in the same syntax, one per line, and the optional --bundle
       option operates the command as a single atomic transation, see option
       --bundle, below.

       [--bundle] add-group switch group
       [--bundle] add-group switch - < file
       [--bundle] add-groups switch file
              Add each group entry to switch's tables.  Each group
              specification (e.g., each line in file) may start with add,
              modify, add_or_mod, delete, insert_bucket, or remove_bucket
              keyword to specify whether a flow is to be added, modified, or
              deleted, or whether a group bucket is to be added or removed.
              For backwards compatibility a group specification without one
              of these keywords is treated as a group add.  All group mods
              are executed in the order specified.

       [--bundle] [--may-create] mod-group switch group
       [--bundle] [--may-create] mod-group switch - < file
              Modify the action buckets in entries from switch's tables for
              each group entry.  If a specified group does not already
              exist, then without --may-create, this command has no effect;
              with --may-create, it creates a new group.  The --may-create
              option uses an Open vSwitch extension to OpenFlow only
              implemented in Open vSwitch 2.6 and later.

       [--bundle] del-groups switch
       [--bundle] del-groups switch [group]
       [--bundle] del-groups switch - < file
              Deletes entries from switch's group table.  With only a switch
              argument, deletes all groups.  Otherwise, deletes the group
              for each group entry.

       [--bundle] insert-buckets switch group
       [--bundle] insert-buckets switch - < file
              Add buckets to an existing group present in the switch's group
              table.  If no command_bucket_id is present in the group
              specification then all buckets of the group are removed.

       [--bundle] remove-buckets switch group
       [--bundle] remove-buckets switch - < file
              Remove buckets to an existing group present in the switch's
              group table.  If no command_bucket_id is present in the group
              specification then all buckets of the group are removed.

   OpenFlow Switch Bundle Command
       Transactional updates to both flow and group tables can be made with
       the bundle command.  file is a text file that contains zero or more
       flow mods, group mods, or packet-outs in Flow Syntax, Group Syntax,
       or Packet-Out Syntax, each line preceded by flow, group, or
       packet-out keyword, correspondingly.  The flow keyword may be
       optionally followed by one of the keywords add, modify,
       modify_strict, delete, or delete_strict, of which the add is assumed
       if a bare flow is given.  Similarly, the group keyword may be
       optionally followed by one of the keywords add, modify, add_or_mod,
       delete, insert_bucket, or remove_bucket, of which the add is assumed
       if a bare group is given.

       bundle switch file
              Execute all flow and group mods in file as a single atomic
              transaction against switch's tables.  All bundled mods are
              executed in the order specified.

   OpenFlow Switch Tunnel TLV Table Commands
       Open vSwitch maintains a mapping table between tunnel option TLVs
       (defined by <class, type, length>) and NXM fields tun_metadatan,
       where n ranges from 0 to 63, that can be operated on for the purposes
       of matches, actions, etc. This TLV table can be used for Geneve
       option TLVs or other protocols with options in same TLV format as
       Geneve options. This mapping must be explicitly specified by the user
       through the following commands.

       A TLV mapping is specified with the syntax
       {class=class,type=type,len=length}->tun_metadatan.  When an option
       mapping exists for a given tun_metadatan, matching on the defined
       field becomes possible, e.g.:

              ovs-ofctl add-tlv-map br0
              "{class=0xffff,type=0,len=4}->tun_metadata0"

              ovs-ofctl add-flow br0 tun_metadata0=1234,actions=controller

       A mapping should not be changed while it is in active use by a flow.
       The result of doing so is undefined.

       These commands are Nicira extensions to OpenFlow and require Open
       vSwitch 2.5 or later.

       add-tlv-map switch option[,option]...
              Add each option to switch's tables. Duplicate fields are
              rejected.

       del-tlv-map switch [option[,option]]...
              Delete each option from switch's table, or all option TLV
              mapping if no option is specified.  Fields that aren't mapped
              are ignored.

       dump-tlv-map switch
              Show the currently mapped fields in the switch's option table
              as well as switch capabilities.

   OpenFlow Switch Monitoring Commands
       snoop switch
              Connects to switch and prints to the console all OpenFlow
              messages received.  Unlike other ovs-ofctl commands, if switch
              is the name of a bridge, then the snoop command connects to a
              Unix domain socket named
              /usr/local/var/run/openvswitch/switch.snoop.  ovs-vswitchd
              listens on such a socket for each bridge and sends to it all
              of the OpenFlow messages sent to or received from its
              configured OpenFlow controller.  Thus, this command can be
              used to view OpenFlow protocol activity between a switch and
              its controller.

              When a switch has more than one controller configured, only
              the traffic to and from a single controller is output.  If
              none of the controllers is configured as a master or a slave
              (using a Nicira extension to OpenFlow 1.0 or 1.1, or a
              standard request in OpenFlow 1.2 or later), then a controller
              is chosen arbitrarily among them.  If there is a master
              controller, it is chosen; otherwise, if there are any
              controllers that are not masters or slaves, one is chosen
              arbitrarily; otherwise, a slave controller is chosen
              arbitrarily.  This choice is made once at connection time and
              does not change as controllers reconfigure their roles.

              If a switch has no controller configured, or if the configured
              controller is disconnected, no traffic is sent, so monitoring
              will not show any traffic.

       monitor switch [miss-len] [invalid_ttl] [watch:[spec...]]
              Connects to switch and prints to the console all OpenFlow
              messages received.  Usually, switch should specify the name of
              a bridge in the ovs-vswitchd database.

              If miss-len is provided, ovs-ofctl sends an OpenFlow ``set
              configuration'' message at connection setup time that requests
              miss-len bytes of each packet that misses the flow table.
              Open vSwitch does not send these and other asynchronous
              messages to an ovs-ofctl monitor client connection unless a
              nonzero value is specified on this argument.  (Thus, if
              miss-len is not specified, very little traffic will ordinarily
              be printed.)

              If invalid_ttl is passed, ovs-ofctl sends an OpenFlow ``set
              configuration'' message at connection setup time that requests
              INVALID_TTL_TO_CONTROLLER, so that ovs-ofctl monitor can
              receive ``packet-in'' messages when TTL reaches zero on
              dec_ttl action.  Only OpenFlow 1.1 and 1.2 support
              invalid_ttl; Open vSwitch also implements it for OpenFlow 1.0
              as an extension.

              watch:[spec...] causes ovs-ofctl to send a ``monitor request''
              Nicira extension message to the switch at connection setup
              time.  This message causes the switch to send information
              about flow table changes as they occur.  The following comma-
              separated spec syntax is available:

              !initial
                     Do not report the switch's initial flow table contents.

              !add   Do not report newly added flows.

              !delete
                     Do not report deleted flows.

              !modify
                     Do not report modifications to existing flows.

              !own   Abbreviate changes made to the flow table by
                     ovs-ofctl's own connection to the switch.  (These could
                     only occur using the ofctl/send command described below
                     under RUNTIME MANAGEMENT COMMANDS.)

              !actions
                     Do not report actions as part of flow updates.

              table=number
                     Limits the monitoring to the table with the given
                     number between 0 and 254.  By default, all tables are
                     monitored.

              out_port=port
                     If set, only flows that output to port are monitored.
                     The port may be an OpenFlow port number or keyword
                     (e.g. LOCAL).

              field=value
                     Monitors only flows that have field specified as the
                     given value.  Any syntax valid for matching on
                     dump-flows may be used.

              This command may be useful for debugging switch or controller
              implementations.  With watch:, it is particularly useful for
              observing how a controller updates flow tables.

   OpenFlow Switch and Controller Commands
       The following commands, like those in the previous section, may be
       applied to OpenFlow switches, using any of the connection methods
       described in that section.  Unlike those commands, these may also be
       applied to OpenFlow controllers.

       probe target
              Sends a single OpenFlow echo-request message to target and
              waits for the response.  With the -t or --timeout option, this
              command can test whether an OpenFlow switch or controller is
              up and running.

       ping target [n]
              Sends a series of 10 echo request packets to target and times
              each reply.  The echo request packets consist of an OpenFlow
              header plus n bytes (default: 64) of randomly generated
              payload.  This measures the latency of individual requests.

       benchmark target n count
              Sends count echo request packets that each consist of an
              OpenFlow header plus n bytes of payload and waits for each
              response.  Reports the total time required.  This is a measure
              of the maximum bandwidth to target for round-trips of n-byte
              messages.

   Other Commands
       ofp-parse file
              Reads file (or stdin if file is -) as a series of OpenFlow
              messages in the binary format used on an OpenFlow connection,
              and prints them to the console.  This can be useful for
              printing OpenFlow messages captured from a TCP stream.

       ofp-parse-pcap file [port...]
              Reads file, which must be in the PCAP format used by network
              capture tools such as tcpdump or wireshark, extracts all the
              TCP streams for OpenFlow connections, and prints the OpenFlow
              messages in those connections in human-readable format on
              stdout.

              OpenFlow connections are distinguished by TCP port number.
              Non-OpenFlow packets are ignored.  By default, data on TCP
              ports 6633 and 6653 are considered to be OpenFlow.  Specify
              one or more port arguments to override the default.

              This command cannot usefully print SSL encrypted traffic.  It
              does not understand IPv6.

   Flow Syntax
       Some ovs-ofctl commands accept an argument that describes a flow or
       flows.  Such flow descriptions comprise a series of field=value
       assignments, separated by commas or white space.  (Embedding spaces
       into a flow description normally requires quoting to prevent the
       shell from breaking the description into multiple arguments.)

       Flow descriptions should be in normal form.  This means that a flow
       may only specify a value for an L3 field if it also specifies a
       particular L2 protocol, and that a flow may only specify an L4 field
       if it also specifies particular L2 and L3 protocol types.  For
       example, if the L2 protocol type dl_type is wildcarded, then L3
       fields nw_src, nw_dst, and nw_proto must also be wildcarded.
       Similarly, if dl_type or nw_proto (the L3 protocol type) is
       wildcarded, so must be the L4 fields tcp_dst and tcp_src.  ovs-ofctl
       will warn about flows not in normal form.

       ovs-fields(7) describes the supported fields and how to match them.
       In addition to match fields, commands that operate on flows accept a
       few additional key-value pairs:

       table=number
              For flow dump commands, limits the flows dumped to those in
              the table with the given number between 0 and 254.  If not
              specified (or if 255 is specified as number), then flows in
              all tables are dumped.

              For flow table modification commands, behavior varies based on
              the OpenFlow version used to connect to the switch:

              OpenFlow 1.0
                     OpenFlow 1.0 does not support table for modifying
                     flows.  ovs-ofctl will exit with an error if table
                     (other than table=255) is specified for a switch that
                     only supports OpenFlow 1.0.

                     In OpenFlow 1.0, the switch chooses the table into
                     which to insert a new flow.  The Open vSwitch software
                     switch always chooses table 0.  Other Open vSwitch
                     datapaths and other OpenFlow implementations may choose
                     different tables.

                     The OpenFlow 1.0 behavior in Open vSwitch for modifying
                     or removing flows depends on whether --strict is used.
                     Without --strict, the command applies to matching flows
                     in all tables.  With --strict, the command will operate
                     on any single matching flow in any table; it will do
                     nothing if there are matches in more than one table.
                     (The distinction between these behaviors only matters
                     if non-OpenFlow 1.0 commands were also used, because
                     OpenFlow 1.0 alone cannot add flows with the same
                     matching criteria to multiple tables.)

              OpenFlow 1.0 with table_id extension
                     Open vSwitch implements an OpenFlow extension that
                     allows the controller to specify the table on which to
                     operate.  ovs-ofctl automatically enables the extension
                     when table is specified and OpenFlow 1.0 is used.
                     ovs-ofctl automatically detects whether the switch
                     supports the extension.  As of this writing, this
                     extension is only known to be implemented by Open
                     vSwitch.

                     With this extension, ovs-ofctl operates on the
                     requested table when table is specified, and acts as
                     described for OpenFlow 1.0 above when no table is
                     specified (or for table=255).

              OpenFlow 1.1
                     OpenFlow 1.1 requires flow table modification commands
                     to specify a table.  When table is not specified (or
                     table=255 is specified), ovs-ofctl defaults to table 0.

              OpenFlow 1.2 and later
                     OpenFlow 1.2 and later allow flow deletion commands,
                     but not other flow table modification commands, to
                     operate on all flow tables, with the behavior described
                     above for OpenFlow 1.0.

       duration=...
       n_packet=...
       n_bytes=...
              ovs-ofctl ignores assignments to these ``fields'' to allow
              output from the dump-flows command to be used as input for
              other commands that parse flows.

       The add-flow, add-flows, and mod-flows commands require an additional
       field, which must be the final field specified:

       actions=[action][,action...]
              Specifies a comma-separated list of actions to take on a
              packet when the flow entry matches.  If no action is
              specified, then packets matching the flow are dropped.  The
              following forms of action are supported:

              port
              output:port
                     Outputs the packet to OpenFlow port number port.  If
                     port is the packet's input port, the packet is not
                     output.

              output:src[start..end]
                     Outputs the packet to the OpenFlow port number read
                     from src, which may be an NXM field name, as described
                     above, or a match field name.  output:reg0[16..31]
                     outputs to the OpenFlow port number written in the
                     upper half of register 0.  If the port number is the
                     packet's input port, the packet is not output.

                     This form of output was added in Open vSwitch 1.3.0.
                     This form of output uses an OpenFlow extension that is
                     not supported by standard OpenFlow switches.

              output(port=port,max_len=nbytes)
                     Outputs the packet to the OpenFlow port number read
                     from port, with maximum packet size set to nbytes.
                     port may be OpenFlow port number, local, or in_port.
                     Patch port is not supported.  Packets larger than
                     nbytes will be trimmed to nbytes while packets smaller
                     than nbytes remains the original size.

              group:group_id
                     Outputs the packet to the OpenFlow group group_id.
                     OpenFlow 1.1 introduced support for groups; Open
                     vSwitch 2.6 and later also supports output to groups as
                     an extension to OpenFlow 1.0.  See Group Syntax for
                     more details.

              normal Subjects the packet to the device's normal L2/L3
                     processing.  (This action is not implemented by all
                     OpenFlow switches.)

              flood  Outputs the packet on all switch physical ports other
                     than the port on which it was received and any ports on
                     which flooding is disabled (typically, these would be
                     ports disabled by the IEEE 802.1D spanning tree
                     protocol).

              all    Outputs the packet on all switch physical ports other
                     than the port on which it was received.

              local  Outputs the packet on the ``local port,'' which
                     corresponds to the network device that has the same
                     name as the bridge.

              in_port
                     Outputs the packet on the port from which it was
                     received.

              controller(key=value...)
                     Sends the packet and its metadata to the OpenFlow
                     controller as a ``packet in'' message.  The supported
                     key-value pairs are:

                     max_len=nbytes
                            Limit to nbytes the number of bytes of the
                            packet to send to the controller.  By default
                            the entire packet is sent.

                     reason=reason
                            Specify reason as the reason for sending the
                            message in the ``packet in'' message.  The
                            supported reasons are action (the default),
                            no_match, and invalid_ttl.

                     id=controller-id
                            Specify controller-id, a 16-bit integer, as the
                            connection ID of the OpenFlow controller or
                            controllers to which the ``packet in'' message
                            should be sent.  The default is zero.  Zero is
                            also the default connection ID for each
                            controller connection, and a given controller
                            connection will only have a nonzero connection
                            ID if its controller uses the
                            NXT_SET_CONTROLLER_ID Nicira extension to
                            OpenFlow.

                     userdata=hh...
                            Supplies the bytes represented as hex digits hh
                            as additional data to the controller in the
                            packet-in message.  Pairs of hex digits may be
                            separated by periods for readability.

                     pause  Causes the switch to freeze the packet's trip
                            through Open vSwitch flow tables and serializes
                            that state into the packet-in message as a
                            ``continuation,'' an additional property in the
                            NXT_PACKET_IN2 message.  The controller can
                            later send the continuation back to the switch
                            in an NXT_RESUME message, which will restart the
                            packet's traversal from the point where it was
                            interrupted.  This permits an OpenFlow
                            controller to interpose on a packet midway
                            through processing in Open vSwitch.

                     If any reason other than action or any nonzero
                     controller-id is supplied, Open vSwitch extension
                     NXAST_CONTROLLER, supported by Open vSwitch 1.6 and
                     later, is used.  If userdata is supplied, then
                     NXAST_CONTROLLER2, supported by Open vSwitch 2.6 and
                     later, is used.

              controller
              controller[:nbytes]
                     Shorthand for controller() or
                     controller(max_len=nbytes), respectively.

              enqueue(port,queue)
                     Enqueues the packet on the specified queue within port
                     port, which must be an OpenFlow port number or keyword
                     (e.g. LOCAL).  The number of supported queues depends
                     on the switch; some OpenFlow implementations do not
                     support queuing at all.

              drop   Discards the packet, so no further processing or
                     forwarding takes place.  If a drop action is used, no
                     other actions may be specified.

              mod_vlan_vid:vlan_vid
                     Modifies the VLAN id on a packet.  The VLAN tag is
                     added or modified as necessary to match the value
                     specified.  If the VLAN tag is added, a priority of
                     zero is used (see the mod_vlan_pcp action to set this).

              mod_vlan_pcp:vlan_pcp
                     Modifies the VLAN priority on a packet.  The VLAN tag
                     is added or modified as necessary to match the value
                     specified.  Valid values are between 0 (lowest) and 7
                     (highest).  If the VLAN tag is added, a vid of zero is
                     used (see the mod_vlan_vid action to set this).

              strip_vlan
                     Strips the VLAN tag from a packet if it is present.

              push_vlan:ethertype
                     Push a new VLAN tag onto the packet.  Ethertype is used
                     as the Ethertype for the tag. Only ethertype 0x8100
                     should be used. (0x88a8 which the spec allows isn't
                     supported at the moment.)  A priority of zero and the
                     tag of zero are used for the new tag.

              push_mpls:ethertype
                     Changes the packet's Ethertype to ethertype, which must
                     be either 0x8847 or 0x8848, and pushes an MPLS LSE.

                     If the packet does not already contain any MPLS labels
                     then an initial label stack entry is pushed.  The label
                     stack entry's label is 2 if the packet contains IPv6
                     and 0 otherwise, its default traffic control value is
                     the low 3 bits of the packet's DSCP value (0 if the
                     packet is not IP), and its TTL is copied from the IP
                     TTL (64 if the packet is not IP).

                     If the packet does already contain an MPLS label,
                     pushes a new outermost label as a copy of the existing
                     outermost label.

                     A limitation of the implementation is that processing
                     of actions will stop if push_mpls follows another
                     push_mpls unless there is a pop_mpls in between.

              pop_mpls:ethertype
                     Strips the outermost MPLS label stack entry.  Currently
                     the implementation restricts ethertype to a non-MPLS
                     Ethertype and thus pop_mpls should only be applied to
                     packets with an MPLS label stack depth of one. A
                     further limitation is that processing of actions will
                     stop if pop_mpls follows another pop_mpls unless there
                     is a push_mpls in between.

              mod_dl_src:mac
                     Sets the source Ethernet address to mac.

              mod_dl_dst:mac
                     Sets the destination Ethernet address to mac.

              mod_nw_src:ip
                     Sets the IPv4 source address to ip.

              mod_nw_dst:ip
                     Sets the IPv4 destination address to ip.

              mod_tp_src:port
                     Sets the TCP or UDP or SCTP source port to port.

              mod_tp_dst:port
                     Sets the TCP or UDP or SCTP destination port to port.

              mod_nw_tos:tos
                     Sets the DSCP bits in the IPv4 ToS/DSCP or IPv6 traffic
                     class field to tos, which must be a multiple of 4
                     between 0 and 255.  This action does not modify the two
                     least significant bits of the ToS field (the ECN bits).

              mod_nw_ecn:ecn
                     Sets the ECN bits in the IPv4 ToS or IPv6 traffic class
                     field to ecn, which must be a value between 0 and 3,
                     inclusive.  This action does not modify the six most
                     significant bits of the field (the DSCP bits).

                     Requires OpenFlow 1.1 or later.

              mod_nw_ttl:ttl
                     Sets the IPv4 TTL or IPv6 hop limit field to ttl, which
                     is specified as a decimal number between 0 and 255,
                     inclusive.  Switch behavior when setting ttl to zero is
                     not well specified, though.

                     Requires OpenFlow 1.1 or later.

              The following actions are Nicira vendor extensions that, as of
              this writing, are only known to be implemented by Open
              vSwitch:

              resubmit:port
              resubmit([port],[table])
              resubmit([port],[table],ct)
                     Re-searches this OpenFlow flow table (or the table
                     whose number is specified by table) with the in_port
                     field replaced by port (if port is specified) and the
                     packet 5-tuple fields swapped with the corresponding
                     conntrack original direction tuple fields (if ct is
                     specified, see ct_nw_src above), and executes the
                     actions found, if any, in addition to any other actions
                     in this flow entry.  The in_port and swapped 5-tuple
                     fields are restored immediately after the search,
                     before any actions are executed.

                     The ct option requires a valid connection tracking
                     state as a match prerequisite in the flow where this
                     action is placed.  Examples of valid connection
                     tracking state matches include ct_state=+new,
                     ct_state=+est, ct_state=+rel, and ct_state=+trk-inv.

                     Recursive resubmit actions are obeyed up to
                     implementation-defined limits:

                     ·      Open vSwitch 1.0.1 and earlier did not support
                            recursion.

                     ·      Open vSwitch 1.0.2 and 1.0.3 limited recursion
                            to 8 levels.

                     ·      Open vSwitch 1.1 and 1.2 limited recursion to 16
                            levels.

                     ·      Open vSwitch 1.2 through 1.8 limited recursion
                            to 32 levels.

                     ·      Open vSwitch 1.9 through 2.0 limited recursion
                            to 64 levels.

                     ·      Open vSwitch 2.1 through 2.5 limited recursion
                            to 64 levels and impose a total limit of 4,096
                            resubmits per flow translation (earlier versions
                            did not impose any total limit).

                     ·      Open vSwitch 2.6 and later imposes the same
                            limits as 2.5, with one exception: resubmit from
                            table x to any table y > x does not count
                            against the recursion limit.

                     Open vSwitch before 1.2.90 did not support table.  Open
                     vSwitch before 2.7 did not support ct.

              set_tunnel:id
              set_tunnel64:id
                     If outputting to a port that encapsulates the packet in
                     a tunnel and supports an identifier (such as GRE), sets
                     the identifier to id.  If the set_tunnel form is used
                     and id fits in 32 bits, then this uses an action
                     extension that is supported by Open vSwitch 1.0 and
                     later.  Otherwise, if id is a 64-bit value, it requires
                     Open vSwitch 1.1 or later.

              set_queue:queue
                     Sets the queue that should be used to queue when
                     packets are output.  The number of supported queues
                     depends on the switch; some OpenFlow implementations do
                     not support queuing at all.

              pop_queue
                     Restores the queue to the value it was before any
                     set_queue actions were applied.

              ct
              ct([argument][,argument...])
                     Send the packet through the connection tracker.  Refer
                     to the ct_state documentation above for possible packet
                     and connection states. A ct action always sets the
                     packet to an untracked state and clears out the
                     ct_state fields for the current processing path.  Those
                     fields are only available for the processing path
                     pointed to by the table argument.  The following
                     arguments are supported:

                     commit
                            Commit the connection to the connection tracking
                            module. Information about the connection will be
                            stored beyond the lifetime of the packet in the
                            pipeline.  Some ct_state flags are only
                            available for committed connections.

                     force
                            A committed connection always has the
                            directionality of the packet that caused the
                            connection to be committed in the first place.
                            This is the ``original direction'' of the
                            connection, and the opposite direction is the
                            ``reply direction''.  If a connection is already
                            committed, but it is in the wrong direction,
                            force flag may be used in addition to commit
                            flag to effectively terminate the existing
                            connection and start a new one in the current
                            direction.  This flag has no effect if the
                            original direction of the connection is already
                            the same as that of the current packet.

                     table=number
                            Fork pipeline processing in two. The original
                            instance of the packet will continue processing
                            the current actions list as an untracked packet.
                            An additional instance of the packet will be
                            sent to the connection tracker, which will be
                            re-injected into the OpenFlow pipeline to resume
                            processing in table number, with the ct_state
                            and other ct match fields set. If the table is
                            not specified, then the packet which is
                            submitted to the connection tracker is not re-
                            injected into the OpenFlow pipeline. It is
                            strongly recommended to specify a table later
                            than the current table to prevent loops.

                     zone=value
                     zone=src[start..end]
                            A 16-bit context id that can be used to isolate
                            connections into separate domains, allowing
                            overlapping network addresses in different
                            zones. If a zone is not provided, then the
                            default is to use zone zero. The zone may be
                            specified either as an immediate 16-bit value,
                            or may be provided from an NXM field src. The
                            start and end pair are inclusive, and must
                            specify a 16-bit range within the field. This
                            value is copied to the ct_zone match field for
                            packets which are re-injected into the pipeline
                            using the table option.

                     exec([action][,action...])
                            Perform actions within the context of connection
                            tracking. This is a restricted set of actions
                            which are in the same format as their
                            specifications as part of a flow. Only actions
                            which modify the ct_mark or ct_label fields are
                            accepted within the exec action, and these
                            fields may only be modified with this option.
                            For example:

                            set_field:value[/mask]->ct_mark
                                   Store a 32-bit metadata value with the
                                   connection.  Subsequent lookups for
                                   packets in this connection will populate
                                   the ct_mark flow field when the packet is
                                   sent to the connection tracker with the
                                   table specified.

                            set_field:value[/mask]->ct_label
                                   Store a 128-bit metadata value with the
                                   connection.  Subsequent lookups for
                                   packets in this connection will populate
                                   the ct_label flow field when the packet
                                   is sent to the connection tracker with
                                   the table specified.

                            The commit parameter must be specified to use
                            exec(...).

                     alg=alg
                            Specify application layer gateway alg to track
                            specific connection types. If subsequent related
                            connections are sent through the ct action, then
                            the rel flag in the ct_state field will be set.
                            Supported types include:

                            ftp    Look for negotiation of FTP data
                                   connections. Specify this option for FTP
                                   control connections to detect related
                                   data connections and populate the rel
                                   flag for the data connections.

                            tftp   Look for negotiation of TFTP data
                                   connections. Specify this option for TFTP
                                   control connections to detect related
                                   data connections and populate the rel
                                   flag for the data connections.

                            The commit parameter must be specified to use
                            alg=alg.

                            When committing related connections, the ct_mark
                            for that connection is inherited from the
                            current ct_mark stored with the original
                            connection (ie, the connection created by
                            ct(alg=...)).

                            Note that with the Linux datapath, global sysctl
                            options affect the usage of the ct action. In
                            particular, if net.netfilter.nf_conntrack_helper
                            is enabled then application layer gateway
                            helpers may be executed even if the alg option
                            is not specified. This is the default setting
                            until Linux 4.7.  For security reasons, the
                            netfilter team recommends users to disable this
                            option. See this blog post for further details:
                            http://www.netfilter.org/news.html#2012-04-03

                     nat[((src|dst)=addr1[-addr2][:port1[-port2]][,flags])]
                            Specify address and port translation for the
                            connection being tracked.  For new connections
                            either src or dst argument must be provided to
                            set up either source address/port translation
                            (SNAT) or destination address/port translation
                            (DNAT), respectively.  Setting up address
                            translation for a new connection takes effect
                            only if the commit flag is also provided for the
                            enclosing ct action.  A bare nat action will
                            only translate the packet being processed in the
                            way the connection has been set up with an
                            earlier ct action.  Also a nat action with src
                            or dst, when applied to a packet belonging to an
                            established (rather than new) connection, will
                            behave the same as a bare nat.

                            src and dst options take the following
                            arguments:

                            addr1[-addr2]
                                   The address range from which the
                                   translated address should be selected.
                                   If only one address is given, then that
                                   address will always be selected,
                                   otherwise the address selection can be
                                   informed by the optional persistent flag
                                   as described below.  Either IPv4 or IPv6
                                   addresses can be provided, but both
                                   addresses must be of the same type, and
                                   the datapath behavior is undefined in
                                   case of providing IPv4 address range for
                                   an IPv6 packet, or IPv6 address range for
                                   an IPv4 packet.  IPv6 addresses must be
                                   bracketed with '[' and ']' if a port
                                   range is also given.

                            port1[-port2]
                                   The port range from which the translated
                                   port should be selected.  If only one
                                   port number is provided, then that should
                                   be selected.  In case of a mapping
                                   conflict the datapath may choose any
                                   other non-conflicting port number
                                   instead, even when no port range is
                                   specified.  The port number selection can
                                   be informed by the optional random and
                                   hash flags as described below.

                            The optional flags are:

                            random The selection of the port from the given
                                   range should be done using a fresh random
                                   number.  This flag is mutually exclusive
                                   with hash.

                            hash   The selection of the port from the given
                                   range should be done using a datapath
                                   specific hash of the packet's IP
                                   addresses and the other, non-mapped port
                                   number.  This flag is mutually exclusive
                                   with random.

                            persistent
                                   The selection of the IP address from the
                                   given range should be done so that the
                                   same mapping can be provided after the
                                   system restarts.

                            If an alg is specified for the committing ct
                            action that also includes nat with a src or dst
                            attribute, then the datapath tries to set up the
                            helper to be NAT aware.  This functionality is
                            datapath specific and may not be supported by
                            all datapaths.

                            nat was introduced in Open vSwitch 2.6.  The
                            first datapath that implements ct nat support is
                            the one that ships with Linux 4.6.

                     The ct action may be used as a primitive to construct
                     stateful firewalls by selectively committing some
                     traffic, then matching the ct_state to allow
                     established connections while denying new connections.
                     The following flows provide an example of how to
                     implement a simple firewall that allows new connections
                     from port 1 to port 2, and only allows established
                     connections to send traffic from port 2 to port 1:
                         table=0,priority=1,action=drop
                         table=0,priority=10,arp,action=normal
                         table=0,priority=100,ip,ct_state=-trk,action=ct(table=1)
                         table=1,in_port=1,ip,ct_state=+trk+new,action=ct(commit),2
                         table=1,in_port=1,ip,ct_state=+trk+est,action=2
                         table=1,in_port=2,ip,ct_state=+trk+new,action=drop
                         table=1,in_port=2,ip,ct_state=+trk+est,action=1

                     If ct is executed on IP (or IPv6) fragments, then the
                     message is implicitly reassembled before sending to the
                     connection tracker and refragmented upon output, to the
                     original maximum received fragment size.  Reassembly
                     occurs within the context of the zone, meaning that IP
                     fragments in different zones are not assembled
                     together. Pipeline processing for the initial fragments
                     is halted; When the final fragment is received, the
                     message is assembled and pipeline processing will
                     continue for that flow.  Because packet ordering is not
                     guaranteed by IP protocols, it is not possible to
                     determine which IP fragment will cause message
                     reassembly (and therefore continue pipeline
                     processing). As such, it is strongly recommended that
                     multiple flows should not execute ct to reassemble
                     fragments from the same IP message.

                     Currently, connection tracking is only available on
                     Linux kernels with the nf_conntrack module loaded. The
                     ct action was introduced in Open vSwitch 2.5.

              ct_clear
                     Clears connection tracking state from the flow, zeroing
                     ct_state, ct_zone, ct_mark, and ct_label.

                     This action was introduced in Open vSwitch 2.6.90.

              dec_ttl
              dec_ttl(id1[,id2]...)
                     Decrement TTL of IPv4 packet or hop limit of IPv6
                     packet.  If the TTL or hop limit is initially zero or
                     decrementing would make it so, no decrement occurs, as
                     packets reaching TTL zero must be rejected.  Instead, a
                     ``packet-in'' message with reason code OFPR_INVALID_TTL
                     is sent to each connected controller that has enabled
                     receiving them, if any.  Processing the current set of
                     actions then stops.  However, if the current set of
                     actions was reached through ``resubmit'' then remaining
                     actions in outer levels resume processing.

                     This action also optionally supports the ability to
                     specify a list of valid controller ids.  Each of the
                     controllers in the list will receive the ``packet_in''
                     message only if they have registered to receive the
                     invalid ttl packets.  If controller ids are not
                     specified, the ``packet_in'' message will be sent only
                     to the controllers having controller id zero which have
                     registered for the invalid ttl packets.

              set_mpls_label:label
                     Set the label of the outer MPLS label stack entry of a
                     packet.  label should be a 20-bit value that is decimal
                     by default; use a 0x prefix to specify them in
                     hexadecimal.

              set_mpls_tc:tc
                     Set the traffic-class of the outer MPLS label stack
                     entry of a packet.  tc should be a in the range 0 to 7
                     inclusive.

              set_mpls_ttl:ttl
                     Set the TTL of the outer MPLS label stack entry of a
                     packet.  ttl should be in the range 0 to 255 inclusive.

              dec_mpls_ttl
                     Decrement TTL of the outer MPLS label stack entry of a
                     packet.  If the TTL is initially zero or decrementing
                     would make it so, no decrement occurs.  Instead, a
                     ``packet-in'' message with reason code OFPR_INVALID_TTL
                     is sent to the main controller (id zero), if it has
                     enabled receiving them.  Processing the current set of
                     actions then stops.  However, if the current set of
                     actions was reached through ``resubmit'' then remaining
                     actions in outer levels resume processing.

              note:[hh]...
                     Does nothing at all.  Any number of bytes represented
                     as hex digits hh may be included.  Pairs of hex digits
                     may be separated by periods for readability.  The note
                     action's format doesn't include an exact length for its
                     payload, so the provided bytes will be padded on the
                     right by enough bytes with value 0 to make the total
                     number 6 more than a multiple of 8.

              move:src[start..end]->dst[start..end]
                     Copies the named bits from field src to field dst.  src
                     and dst may be NXM field names as defined in
                     nicira-ext.h, e.g. NXM_OF_UDP_SRC or NXM_NX_REG0, or a
                     match field name, e.g. reg0.  Each start and end pair,
                     which are inclusive, must specify the same number of
                     bits and must fit within its respective field.
                     Shorthands for [start..end] exist: use [bit] to specify
                     a single bit or [] to specify an entire field (in the
                     latter case the brackets can also be left off).

                     Examples: move:NXM_NX_REG0[0..5]->NXM_NX_REG1[26..31]
                     copies the six bits numbered 0 through 5, inclusive, in
                     register 0 into bits 26 through 31, inclusive;
                     move:reg0[0..15]->vlan_tci copies the least significant
                     16 bits of register 0 into the VLAN TCI field.

                     In OpenFlow 1.0 through 1.4, move ordinarily uses an
                     Open vSwitch extension to OpenFlow.  In OpenFlow 1.5,
                     move uses the OpenFlow 1.5 standard copy_field action.
                     The ONF has also made copy_field available as an
                     extension to OpenFlow 1.3.  Open vSwitch 2.4 and later
                     understands this extension and uses it if a controller
                     uses it, but for backward compatibility with older
                     versions of Open vSwitch, ovs-ofctl does not use it.

              set_field:value[/mask]->dst
              load:value->dst[start..end]
                     Loads a literal value into a field or part of a field.
                     With set_field, value and the optional mask are given
                     in the customary syntax for field dst, which is
                     expressed as a field name.  For example,
                     set_field:00:11:22:33:44:55->eth_src sets the Ethernet
                     source address to 00:11:22:33:44:55.  With load, value
                     must be an integer value (in decimal or prefixed by 0x
                     for hexadecimal) and dst can also be the NXM or OXM
                     name for the field.  For example,
                     load:0x001122334455->OXM_OF_ETH_SRC[] has the same
                     effect as the prior set_field example.

                     The two forms exist for historical reasons.  Open
                     vSwitch 1.1 introduced NXAST_REG_LOAD as a Nicira
                     extension to OpenFlow 1.0 and used load to express it.
                     Later, OpenFlow 1.2 introduced a standard
                     OFPAT_SET_FIELD action that was restricted to loading
                     entire fields, so Open vSwitch added the form set_field
                     with this restriction.  OpenFlow 1.5 extended
                     OFPAT_SET_FIELD to the point that it became a superset
                     of NXAST_REG_LOAD.  Open vSwitch translates either
                     syntax as necessary for the OpenFlow version in use: in
                     OpenFlow 1.0 and 1.1, NXAST_REG_LOAD; in OpenFlow 1.2,
                     1.3, and 1.4, NXAST_REG_LOAD for load or for loading a
                     subfield, OFPAT_SET_FIELD otherwise; and OpenFlow 1.5
                     and later, OFPAT_SET_FIELD.

              push:src[start..end]
                     Pushes start to end bits inclusive, in fields on top of
                     the stack.

                     Example: push:NXM_NX_REG2[0..5] or push:reg2[0..5] push
                     the value stored in register 2 bits 0 through 5,
                     inclusive, on to the internal stack.

              pop:dst[start..end]
                     Pops from the top of the stack, retrieves the start to
                     end bits inclusive, from the value popped and store
                     them into the corresponding bits in dst.

                     Example: pop:NXM_NX_REG2[0..5] or pop:reg2[0..5] pops
                     the value from top of the stack.  Set register 2 bits 0
                     through 5, inclusive, based on bits 0 through 5 from
                     the value just popped.

              multipath(fields, basis, algorithm, n_links, arg,
              dst[start..end])
                     Hashes fields using basis as a universal hash
                     parameter, then the applies multipath link selection
                     algorithm (with parameter arg) to choose one of n_links
                     output links numbered 0 through n_links minus 1, and
                     stores the link into dst[start..end], which must be an
                     NXM field as described above.

                     fields must be one of the following:

                     eth_src
                            Hashes Ethernet source address only.

                     symmetric_l4
                            Hashes Ethernet source, destination, and type,
                            VLAN ID, IPv4/IPv6 source, destination, and
                            protocol, and TCP or SCTP (but not UDP) ports.
                            The hash is computed so that pairs of
                            corresponding flows in each direction hash to
                            the same value, in environments where L2 paths
                            are the same in each direction.  UDP ports are
                            not included in the hash to support protocols
                            such as VXLAN that use asymmetric ports in each
                            direction.

                     symmetric_l3l4
                            Hashes IPv4/IPv6 source, destination, and
                            protocol, and TCP or SCTP (but not UDP) ports.
                            Like symmetric_l4, this is a symmetric hash, but
                            by excluding L2 headers it is more effective in
                            environments with asymmetric L2 paths (e.g.
                            paths involving VRRP IP addresses on a router).
                            Not an effective hash function for protocols
                            other than IPv4 and IPv6, which hash to a
                            constant zero.

                     symmetric_l3l4+udp
                            Like symmetric_l3l4+udp, but UDP ports are
                            included in the hash.  This is a more effective
                            hash when asymmetric UDP protocols such as VXLAN
                            are not a consideration.

                     nw_src Hashes Network source address only.

                     nw_dst Hashes Network destination address only.

                     algorithm must be one of modulo_n, hash_threshold, hrw,
                     and iter_hash.  Only the iter_hash algorithm uses arg.

                     Refer to nicira-ext.h for more details.

              bundle(fields, basis, algorithm, slave_type, slaves:[s1, s2,
              ...])
                     Hashes fields using basis as a universal hash
                     parameter, then applies the bundle link selection
                     algorithm to choose one of the listed slaves
                     represented as slave_type.  Currently the only
                     supported slave_type is ofport.  Thus, each s1 through
                     sN should be an OpenFlow port number. Outputs to the
                     selected slave.

                     Currently, fields must be either eth_src, symmetric_l4,
                     symmetric_l3l4, symmetric_l3l4+udp, nw_src, or nw_dst,
                     and algorithm must be one of hrw and active_backup.

                     Example: bundle(eth_src,0,hrw,ofport,slaves:4,8) uses
                     an Ethernet source hash with basis 0, to select between
                     OpenFlow ports 4 and 8 using the Highest Random Weight
                     algorithm.

                     Refer to nicira-ext.h for more details.

              bundle_load(fields, basis, algorithm, slave_type,
              dst[start..end], slaves:[s1, s2, ...])
                     Has the same behavior as the bundle action, with one
                     exception.  Instead of outputting to the selected
                     slave, it writes its selection to dst[start..end],
                     which must be an NXM field as described above.

                     Example: bundle_load(eth_src, 0, hrw, ofport,
                     NXM_NX_REG0[], slaves:4, 8) uses an Ethernet source
                     hash with basis 0, to select between OpenFlow ports 4
                     and 8 using the Highest Random Weight algorithm, and
                     writes the selection to NXM_NX_REG0[].  Also the match
                     field name can be used, for example, instead of
                     'NXM_NX_REG0' the name 'reg0' can be used.  When the
                     while field is indicated the empty brackets can also be
                     left off.

                     Refer to nicira-ext.h for more details.

              learn(argument[,argument]...)
                     This action adds or modifies a flow in an OpenFlow
                     table, similar to ovs-ofctl --strict mod-flows.  The
                     arguments specify the flow's match fields, actions, and
                     other properties, as follows.  At least one match
                     criterion and one action argument should ordinarily be
                     specified.

                     idle_timeout=seconds
                     hard_timeout=seconds
                     priority=value
                     cookie=value
                     send_flow_rem
                            These arguments have the same meaning as in the
                            usual ovs-ofctl flow syntax.

                     fin_idle_timeout=seconds
                     fin_hard_timeout=seconds
                            Adds a fin_timeout action with the specified
                            arguments to the new flow.  This feature was
                            added in Open vSwitch 1.5.90.

                     table=number
                            The table in which the new flow should be
                            inserted.  Specify a decimal number between 0
                            and 254.  The default, if table is unspecified,
                            is table 1.

                     delete_learned
                            This flag enables deletion of the learned flows
                            when the flow with the learn action is removed.
                            Specifically, when the last learn action with
                            this flag and particular table and cookie values
                            is removed, the switch deletes all of the flows
                            in the specified table with the specified
                            cookie.

                            This flag was added in Open vSwitch 2.4.

                     limit=number
                            If the number of flows in table table with
                            cookie id cookie exceeds number, a new flow will
                            not be learned by this action.  By default
                            there's no limit. limit=0 is a long-hand for no
                            limit.

                            This flag was added in Open vSwitch 2.8.

                     result_dst=field[bit]
                            If learning failed (because the number of flows
                            exceeds limit), the action sets field[bit] to 0,
                            otherwise it will be set to 1.  field[bit] must
                            be a single bit.

                            This flag was added in Open vSwitch 2.8.

                     field=value
                     field[start..end]=src[start..end]
                     field[start..end]
                            Adds a match criterion to the new flow.

                            The first form specifies that field must match
                            the literal value, e.g. dl_type=0x0800.  All of
                            the fields and values for ovs-ofctl flow syntax
                            are available with their usual meanings.
                            Shorthand notation matchers (e.g. ip in place of
                            dl_type=0x0800) are not currently implemented.

                            The second form specifies that field[start..end]
                            in the new flow must match src[start..end] taken
                            from the flow currently being processed.  For
                            example, NXM_OF_UDP_DST[]=NXM_OF_UDP_SRC[] on a
                            TCP packet for which the UDP src port is 53,
                            creates a flow which matches
                            NXM_OF_UDP_DST[]=53.

                            The third form is a shorthand for the second
                            form.  It specifies that field[start..end] in
                            the new flow must match the same
                            field[start..end] taken from the flow currently
                            being processed.  For example, NXM_OF_TCP_DST[]
                            on a TCP packet for which the TCP dst port is
                            80, creates a flow which matches
                            NXM_OF_TCP_DST[]=80.

                     load:value->dst[start..end]
                     load:src[start..end]->dst[start..end]
                            Adds a load action to the new flow.

                            The first form loads the literal value into bits
                            start through end, inclusive, in field dst.  Its
                            syntax is the same as the load action described
                            earlier in this section.

                            The second form loads src[start..end], a value
                            from the flow currently being processed, into
                            bits start through end, inclusive, in field dst.

                     output:field[start..end]
                            Add an output action to the new flow's actions,
                            that outputs to the OpenFlow port taken from
                            field[start..end], which must be an NXM field as
                            described above.

                     For best performance, segregate learned flows into a
                     table (using table=number) that is not used for any
                     other flows except possibly for a lowest-priority
                     ``catch-all'' flow, that is, a flow with no match
                     criteria.  (This is why the default table is 1, to keep
                     the learned flows separate from the primary flow table
                     0.)

              clear_actions
                     Clears all the actions in the action set immediately.

              write_actions([action][,action...])
                     Add the specific actions to the action set.  The syntax
                     of actions is the same as in the actions= field.  The
                     action set is carried between flow tables and then
                     executed at the end of the pipeline.

                     The actions in the action set are applied in the
                     following order, as required by the OpenFlow
                     specification, regardless of the order in which they
                     were added to the action set.  Except as specified
                     otherwise below, the action set only holds at most a
                     single action of each type.  When more than one action
                     of a single type is written to the action set, the one
                     written later replaces the earlier action:

                     1.     strip_vlan
                            pop_mpls

                     2.     decap

                     3.     encap

                     4.     push_mpls

                     5.     push_vlan

                     6.     dec_ttl
                            dec_mpls_ttl

                     7.     load
                            move
                            mod_dl_dst
                            mod_dl_src
                            mod_nw_dst
                            mod_nw_src
                            mod_nw_tos
                            mod_nw_ecn
                            mod_nw_ttl
                            mod_tp_dst
                            mod_tp_src
                            mod_vlan_pcp
                            mod_vlan_vid
                            set_field
                            set_tunnel
                            set_tunnel64
                            The action set can contain any number of these
                            actions, with cumulative effect. They will be
                            applied in the order as added.  That is, when
                            multiple actions modify the same part of a
                            field, the later modification takes effect, and
                            when they modify different parts of a field (or
                            different fields), then both modifications are
                            applied.

                     8.     set_queue

                     9.     group
                            output
                            resubmit
                            If more than one of these actions is present,
                            then the one listed earliest above is executed
                            and the others are ignored, regardless of the
                            order in which they were added to the action
                            set.  (If none of these actions is present, the
                            action set has no real effect, because the
                            modified packet is not sent anywhere and thus
                            the modifications are not visible.)

                     Only the actions listed above may be written to the
                     action set.  encap and decap actions are nonstandard.

              write_metadata:value[/mask]
                     Updates the metadata field for the flow. If mask is
                     omitted, the metadata field is set exactly to value; if
                     mask is specified, then a 1-bit in mask indicates that
                     the corresponding bit in the metadata field will be
                     replaced with the corresponding bit from value. Both
                     value and mask are 64-bit values that are decimal by
                     default; use a 0x prefix to specify them in
                     hexadecimal.

              meter:meter_id
                     Apply the meter_id before any other actions. If a meter
                     band rate is exceeded, the packet may be dropped, or
                     modified, depending on the meter band type. See the
                     description of the Meter Table Commands, above, for
                     more details.

              goto_table:table
                     Indicates the next table in the process pipeline.

              fin_timeout(argument[,argument])
                     This action changes the idle timeout or hard timeout,
                     or both, of this OpenFlow rule when the rule matches a
                     TCP packet with the FIN or RST flag.  When such a
                     packet is observed, the action reduces the rule's
                     timeouts to those specified on the action.  If the
                     rule's existing timeout is already shorter than the one
                     that the action specifies, then that timeout is
                     unaffected.

                     argument takes the following forms:

                     idle_timeout=seconds
                            Causes the flow to expire after the given number
                            of seconds of inactivity.

                     hard_timeout=seconds
                            Causes the flow to expire after the given number
                            of seconds, regardless of activity.  (seconds
                            specifies time since the flow's creation, not
                            since the receipt of the FIN or RST.)

                     This action was added in Open vSwitch 1.5.90.

              sample(argument[,argument]...)
                     Samples packets and sends one sample for every sampled
                     packet.

                     argument takes the following forms:

                     probability=packets
                            The number of sampled packets out of 65535.
                            Must be greater or equal to 1.

                     collector_set_id=id
                            The unsigned 32-bit integer identifier of the
                            set of sample collectors to send sampled packets
                            to.  Defaults to 0.

                     obs_domain_id=id
                            When sending samples to IPFIX collectors, the
                            unsigned 32-bit integer Observation Domain ID
                            sent in every IPFIX flow record.  Defaults to 0.

                     obs_point_id=id
                            When sending samples to IPFIX collectors, the
                            unsigned 32-bit integer Observation Point ID
                            sent in every IPFIX flow record.  Defaults to 0.

                     sampling_port=port
                            Sample packets on port, which should be the
                            ingress or egress port.  This option, which was
                            added in Open vSwitch 2.5.90, allows the IPFIX
                            implementation to export egress tunnel
                            information.

                     ingress
                     egress Specifies explicitly that the packet is being
                            sampled on ingress to or egress from the switch.
                            IPFIX reports sent by Open vSwitch before
                            version 2.5.90 did not include a direction.
                            From 2.5.90 until 2.6.90, IPFIX reports inferred
                            a direction from sampling_port: if it was the
                            packet's output port, then the direction was
                            reported as egress, otherwise as ingress.  Open
                            vSwitch 2.6.90 introduced these options, which
                            allow the inferred direction to be overridden.
                            This is particularly useful when the ingress (or
                            egress) port is not a tunnel.

                     Refer to ovs-vswitchd.conf.db(5) for more details on
                     configuring sample collector sets.

                     This action was added in Open vSwitch 1.10.90.

              exit   This action causes Open vSwitch to immediately halt
                     execution of further actions.  Those actions which have
                     already been executed are unaffected.  Any further
                     actions, including those which may be in other tables,
                     or different levels of the resubmit call stack, are
                     ignored.  Actions in the action set is still executed
                     (specify clear_actions before exit to discard them).

              conjunction(id, k/n)
                     This action allows for sophisticated ``conjunctive
                     match'' flows.  Refer to CONJUNCTIVE MATCH FIELDS in
                     ovs-fields(7) for details.

                     The conjunction action and conj_id field were
                     introduced in Open vSwitch 2.4.

              clone([action][,action...])
                     Executes each nested action, saving much of the packet
                     and pipeline state beforehand and then restoring it
                     afterward.  The state that is saved and restored
                     includes all flow data and metadata (including, for
                     example, ct_state), the stack accessed by push and pop
                     actions, and the OpenFlow action set.

                     This action was added in Open vSwitch 2.6.90.

              encap(header[(prop=value,tlv(class,type,value),...)])
                     Encapsulates the packet with a new packet header, e.g.,
                     ethernet or nsh.

                     header Used to specify encapsulation header type.

                     prop=value
                            Used to specify the initial value for the
                            property in the encapsulation header.

                     tlv(class,type,value)
                            Used to specify the initial value for the TLV
                            (Type Length Value) in the encapsulation header.

                     For example, encap(ethernet) will encapsulate the L3
                     packet with Ethernet header.

                     encap(nsh(md_type=1)) will encapsulate the packet with
                     nsh header and nsh metadata type 1.

                     encap(nsh(md_type=2,tlv(0x1000,10,0x12345678))) will
                     encapsulate the packet with nsh header and nsh metadata
                     type 2, and the nsh TLV with class 0x1000 and type 10
                     is set to 0x12345678.

                     prop=value is just used to set some necessary fields
                     for encapsulation header initialization. Other fields
                     in the encapsulation header must be set by set_field
                     action. New encapsulation header implementation must
                     add new match fields and corresponding set action in
                     order that set_field action can change the fields in
                     the encapsulation header on demand.

                     encap(nsh(md_type=1)),
                     set_field:0x1234->nsh_spi,set_field:0x11223344->nsh_c1
                     is an example to encapsulate nsh header and set nsh spi
                     and c1.

                     This action was added in Open vSwitch 2.8.

              decap([packet_type(ns=namespace,type=type)])
                     Decapsulates the outer packet header.

                     packet_type(ns=namespace,type=type)
                            It is optional and used to specify the outer
                            header type of the decapsulated packet.
                            namespace is 0 for Ethernet packet, 1 for L3
                            packet, type is L3 protocol type, e.g., 0x894f
                            for nsh, 0x0 for Ethernet.

                     By default, decap() will decapsulate the outer packet
                     header according to the packet header type, if
                     packet_type(ns=namespace,type=type) is given, it will
                     decapsulate the given packet header, it will fail if
                     the actual outer packet header type is not of
                     packet_type(ns=namespace,type=type).

                     This action was added in Open vSwitch 2.8.

       An opaque identifier called a cookie can be used as a handle to
       identify a set of flows:

       cookie=value
              A cookie can be associated with a flow using the add-flow,
              add-flows, and mod-flows commands.  value can be any 64-bit
              number and need not be unique among flows.  If this field is
              omitted, a default cookie value of 0 is used.

       cookie=value/mask
              When using NXM, the cookie can be used as a handle for
              querying, modifying, and deleting flows.  value and mask may
              be supplied for the del-flows, mod-flows, dump-flows, and
              dump-aggregate commands to limit matching cookies.  A 1-bit in
              mask indicates that the corresponding bit in cookie must match
              exactly, and a 0-bit wildcards that bit.  A mask of -1 may be
              used to exactly match a cookie.

              The mod-flows command can update the cookies of flows that
              match a cookie by specifying the cookie field twice (once with
              a mask for matching and once without to indicate the new
              value):

              ovs-ofctl mod-flows br0 cookie=1,actions=normal
                     Change all flows' cookies to 1 and change their actions
                     to normal.

              ovs-ofctl mod-flows br0 cookie=1/-1,cookie=2,actions=normal
                     Update cookies with a value of 1 to 2 and change their
                     actions to normal.

              The ability to match on cookies was added in Open vSwitch
              1.5.0.

       The following additional field sets the priority for flows added by
       the add-flow and add-flows commands.  For mod-flows and del-flows
       when --strict is specified, priority must match along with the rest
       of the flow specification.  For mod-flows without --strict, priority
       is only significant if the command creates a new flow, that is, non-
       strict mod-flows does not match on priority and will not change the
       priority of existing flows.  Other commands do not allow priority to
       be specified.

       priority=value
              The priority at which a wildcarded entry will match in
              comparison to others.  value is a number between 0 and 65535,
              inclusive.  A higher value will match before a lower one.  An
              exact-match entry will always have priority over an entry
              containing wildcards, so it has an implicit priority value of
              65535.  When adding a flow, if the field is not specified, the
              flow's priority will default to 32768.

              OpenFlow leaves behavior undefined when two or more flows with
              the same priority can match a single packet.  Some users
              expect ``sensible'' behavior, such as more specific flows
              taking precedence over less specific flows, but OpenFlow does
              not specify this and Open vSwitch does not implement it.
              Users should therefore take care to use priorities to ensure
              the behavior that they expect.

       The add-flow, add-flows, and mod-flows commands support the following
       additional options.  These options affect only new flows.  Thus, for
       add-flow and add-flows, these options are always significant, but for
       mod-flows they are significant only if the command creates a new
       flow, that is, their values do not update or affect existing flows.

       idle_timeout=seconds
              Causes the flow to expire after the given number of seconds of
              inactivity.  A value of 0 (the default) prevents a flow from
              expiring due to inactivity.

       hard_timeout=seconds
              Causes the flow to expire after the given number of seconds,
              regardless of activity.  A value of 0 (the default) gives the
              flow no hard expiration deadline.

       importance=value
              Sets the importance of a flow.  The flow entry eviction
              mechanism can use importance as a factor in deciding which
              flow to evict.  A value of 0 (the default) makes the flow non-
              evictable on the basis of importance.  Specify a value between
              0 and 65535.

              Only OpenFlow 1.4 and later support importance.

       send_flow_rem
              Marks the flow with a flag that causes the switch to generate
              a ``flow removed'' message and send it to interested
              controllers when the flow later expires or is removed.

       check_overlap
              Forces the switch to check that the flow match does not
              overlap that of any different flow with the same priority in
              the same table.  (This check is expensive so it is best to
              avoid it.)

       reset_counts
              When this flag is specified on a flow being added to a switch,
              and the switch already has a flow with an identical match, an
              OpenFlow 1.2 (or later) switch resets the flow's packet and
              byte counters to 0.  Without the flag, the packet and byte
              counters are preserved.

              OpenFlow 1.0 and 1.1 switches always reset counters in this
              situation, as if reset_counts were always specified.

              Open vSwitch 1.10 added support for reset_counts.

       no_packet_counts
       no_byte_counts
              Adding these flags to a flow advises an OpenFlow 1.3 (or
              later) switch that the controller does not need packet or byte
              counters, respectively, for the flow.  Some switch
              implementations might achieve higher performance or reduce
              resource consumption when these flags are used.  These flags
              provide no benefit to the Open vSwitch software switch
              implementation.

              OpenFlow 1.2 and earlier do not support these flags.

              Open vSwitch 1.10 added support for no_packet_counts and
              no_byte_counts.

       The dump-flows, dump-aggregate, del-flow and del-flows commands
       support these additional optional fields:

       out_port=port
              If set, a matching flow must include an output action to port,
              which must be an OpenFlow port number or name (e.g. local).

       out_group=port
              If set, a matching flow must include an group action naming
              group, which must be an OpenFlow group number.  This field is
              supported in Open vSwitch 2.5 and later and requires OpenFlow
              1.1 or later.

   Table Entry Output
       The dump-tables and dump-aggregate commands print information about
       the entries in a datapath's tables.  Each line of output is a flow
       entry as described in Flow Syntax, above, plus some additional
       fields:

       duration=secs
              The time, in seconds, that the entry has been in the table.
              secs includes as much precision as the switch provides,
              possibly to nanosecond resolution.

       n_packets
              The number of packets that have matched the entry.

       n_bytes
              The total number of bytes from packets that have matched the
              entry.

       The following additional fields are included only if the switch is
       Open vSwitch 1.6 or later and the NXM flow format is used to dump the
       flow (see the description of the --flow-format option below).  The
       values of these additional fields are approximations only and in
       particular idle_age will sometimes become nonzero even for busy
       flows.

       hard_age=secs
              The integer number of seconds since the flow was added or
              modified.  hard_age is displayed only if it differs from the
              integer part of duration.  (This is separate from duration
              because mod-flows restarts the hard_timeout timer without
              zeroing duration.)

       idle_age=secs
              The integer number of seconds that have passed without any
              packets passing through the flow.

   Packet-Out Syntax
       ovs-ofctl bundle command accepts packet-outs to be specified in the
       bundle file.  Each packet-out comprises of a series of field=value
       assignments, separated by commas or white space.  (Embedding spaces
       into a packet-out description normally requires quoting to prevent
       the shell from breaking the description into multiple arguments.).
       Unless noted otherwise only the last instance of each field is
       honoured.  This same syntax is also supported by the ovs-ofctl
       packet-out command.

       in_port=port
              The port number to be considered the in_port when processing
              actions.  This can be any valid OpenFlow port number, or any
              of the LOCAL, CONTROLLER, or NONE.  This field is required.

       pipeline_field=value
              Optionally, user can specify a list of pipeline fields for a
              packet-out message. The supported pipeline fields includes
              tunnel fields and register fields as defined in ovs-fields(7).

       packet=hex-string
              The actual packet to send, expressed as a string of
              hexadecimal bytes.  This field is required.

       actions=[action][,action...]
              The syntax of actions are identical to the actions= field
              described in Flow Syntax above.  Specifying actions= is
              optional, but omitting actions is interpreted as a drop, so
              the packet will not be sent anywhere from the switch.  actions
              must be specified at the end of each line, like for flow mods.

   Group Syntax
       Some ovs-ofctl commands accept an argument that describes a group or
       groups.  Such flow descriptions comprise a series field=value
       assignments, separated by commas or white space.  (Embedding spaces
       into a group description normally requires quoting to prevent the
       shell from breaking the description into multiple arguments.). Unless
       noted otherwise only the last instance of each field is honoured.

       group_id=id
              The integer group id of group.  When this field is specified
              in del-groups or dump-groups, the keyword "all" may be used to
              designate all groups.  This field is required.

       type=type
              The type of the group.  The add-group, add-groups and mod-
              groups commands require this field.  It is prohibited for
              other commands. The following keywords designated the allowed
              types:

              all    Execute all buckets in the group.

              select Execute one bucket in the group, balancing across the
                     buckets according to their weights.  To select a
                     bucket, for each live bucket, Open vSwitch hashes flow
                     data with the bucket ID and multiplies by the bucket
                     weight to obtain a ``score,'' and then selects the
                     bucket with the highest score.  Use selection_method to
                     control the flow data used for selection.

              indirect
                     Executes the one bucket in the group.

              ff
              fast_failover
                     Executes the first live bucket in the group which is
                     associated with a live port or group.

       command_bucket_id=id
              The bucket to operate on.  The insert-buckets and remove-
              buckets commands require this field.  It is prohibited for
              other commands.  id may be an integer or one of the following
              keywords:

              all    Operate on all buckets in the group.  Only valid when
                     used with the remove-buckets command in which case the
                     effect is to remove all buckets from the group.

              first  Operate on the first bucket present in the group.  In
                     the case of the insert-buckets command the effect is to
                     insert new bucets just before the first bucket already
                     present in the group; or to replace the buckets of the
                     group if there are no buckets already present in the
                     group.  In the case of the remove-buckets command the
                     effect is to remove the first bucket of the group; or
                     do nothing if there are no buckets present in the
                     group.

              last   Operate on the last bucket present in the group.  In
                     the case of the insert-buckets command the effect is to
                     insert new bucets just after the last bucket already
                     present in the group; or to replace the buckets of the
                     group if there are no buckets already present in the
                     group.  In the case of the remove-buckets command the
                     effect is to remove the last bucket of the group; or do
                     nothing if there are no buckets present in the group.

              If id is an integer then it should correspond to the bucket_id
              of a bucket present in the group.  In case of the insert-
              buckets command the effect is to insert buckets just before
              the bucket in the group whose bucket_id is id.  In case of the
              iremove-buckets command the effect is to remove the in the
              group whose bucket_id is id.  It is an error if there is no
              bucket persent group in whose bucket_id is id.

       selection_method=method
              The selection method used to select a bucket for a select
              group.  This is a string of 1 to 15 bytes in length known to
              lower layers.  This field is optional for add-group,
              add-groups and mod-group commands on groups of type select.
              Prohibited otherwise. The default value is the empty string.

              hash   Use a hash computed over the fields specified with the
                     fields option, see below.  hash uses the
                     selection_method_param as the hash basis.

                     Note that the hashed fields become exact matched by the
                     datapath flows.  For example, if the TCP source port is
                     hashed, the created datapath flows will match the
                     specific TCP source port value present in the packet
                     received.  Since each TCP connection generally has a
                     different source port value, a separate datapath flow
                     will be need to be inserted for each TCP connection
                     thus hashed to a select group bucket.

              dp_hash
                     Use a datapath computed hash value.  The hash algorithm
                     varies accross different datapath implementations.
                     dp_hash uses the upper 32 bits of the
                     selection_method_param as the datapath hash algorithm
                     selector, which currently must always be 0,
                     corresponding to hash computation over the IP 5-tuple
                     (selecting specific fields with the fields option is
                     not allowed with dp_hash).  The lower 32 bits are used
                     as the hash basis.

                     Using dp_hash has the advantage that it does not
                     require the generated datapath flows to exact match any
                     additional packet header fields.  For example, even if
                     multiple TCP connections thus hashed to different
                     select group buckets have different source port
                     numbers, generally all of them would be handled with a
                     small set of already established datapath flows,
                     resulting in less latency for TCP SYN packets.  The
                     downside is that the shared datapath flows must match
                     each packet twice, as the datapath hash value
                     calculation happens only when needed, and a second
                     match is required to match some bits of its value.
                     This double-matching incurs a small additional latency
                     cost for each packet, but this latency is orders of
                     magnitude less than the latency of creating new
                     datapath flows for new TCP connections.

              This option will use a Netronome OpenFlow extension which is
              only supported when using Open vSwitch 2.4 and later with
              OpenFlow 1.5 and later.

       selection_method_param=param
              64-bit integer parameter to the selection method selected by
              the selection_method field.  The parameter's use is defined by
              the lower-layer that implements the selection_method.  It is
              optional if the selection_method field is specified as a non-
              empty string.  Prohibited otherwise. The default value is
              zero.

              This option will use a Netronome OpenFlow extension which is
              only supported when using Open vSwitch 2.4 and later with
              OpenFlow 1.5 and later.

       fields=field
       fields(field[=mask]...)
              The field parameters to selection method selected by the
              selection_method field.  The syntax is described in Flow
              Syntax with the additional restrictions that if a value is
              provided it is treated as a wildcard mask and wildcard masks
              following a slash are prohibited. The pre-requisites of fields
              must be provided by any flows that output to the group.  The
              use of the fields is defined by the lower-layer that
              implements the selection_method.  They are optional if the
              selection_method field is specified as ``hash', prohibited
              otherwise.  The default is no fields.

              This option will use a Netronome OpenFlow extension which is
              only supported when using Open vSwitch 2.4 and later with
              OpenFlow 1.5 and later.

       bucket=bucket_parameters
              The add-group, add-groups and mod-group commands require at
              least one bucket field. Bucket fields must appear after all
              other fields.  Multiple bucket fields to specify multiple
              buckets.  The order in which buckets are specified corresponds
              to their order in the group. If the type of the group is
              "indirect" then only one group may be specified.
              bucket_parameters consists of a list of field=value
              assignments, separated by commas or white space followed by a
              comma-separated list of actions.  The fields for
              bucket_parameters are:

              bucket_id=id
                     The 32-bit integer group id of the bucket.  Values
                     greater than 0xffffff00 are reserved.  This field was
                     added in Open vSwitch 2.4 to conform with the OpenFlow
                     1.5 specification. It is not supported when earlier
                     versions of OpenFlow are used.  Open vSwitch will
                     automatically allocate bucket ids when they are not
                     specified.

              actions=[action][,action...]
                     The syntax of actions are identical to the actions=
                     field described in Flow Syntax above. Specifying
                     actions= is optional, any unknown bucket parameter will
                     be interpreted as an action.

              weight=value
                     The relative weight of the bucket as an integer. This
                     may be used by the switch during bucket select for
                     groups whose type is select.

              watch_port=port
                     Port used to determine liveness of group.  This or the
                     watch_group field is required for groups whose type is
                     ff or fast_failover.

              watch_group=group_id
                     Group identifier of group used to determine liveness of
                     group.  This or the watch_port field is required for
                     groups whose type is ff or fast_failover.

   Meter Syntax
       The meter table commands accept an argument that describes a meter.
       Such meter descriptions comprise a series field=value assignments,
       separated by commas or white space.  (Embedding spaces into a group
       description normally requires quoting to prevent the shell from
       breaking the description into multiple arguments.). Unless noted
       otherwise only the last instance of each field is honoured.

       meter=id
              The integer meter id of the meter.  When this field is
              specified in del-meter, dump-meter, or meter-stats, the
              keyword "all" may be used to designate all meters.  This field
              is required, exept for meter-stats, which dumps all stats when
              this field is not specified.

       kbps
       pktps  The unit for the meter band rate parameters, either kilobits
              per second, or packets per second, respectively.  One of these
              must be specified.  The burst size unit corresponds to the
              rate unit by dropping the "per second", i.e., burst is in
              units of kilobits or packets, respectively.

       burst  Specify burst size for all bands, or none of them, if this
              flag is not given.

       stats  Collect meter and band statistics.

       bands=band_parameters
              The add-meter and mod-meter commands require at least one band
              specification. Bands must appear after all other fields.

              type=type
                     The type of the meter band.  This keyword starts a new
                     band specification.  Each band specifies a rate above
                     which the band is to take some action. The action
                     depends on the band type.  If multiple bands' rate is
                     exceeded, then the band with the highest rate among the
                     exceeded bands is selected.  The following keywords
                     designate the allowed meter band types:

                     drop   Drop packets exceeding the band's rate limit.

              The other band_parameters are:

              rate=value
                     The relative rate limit for this band, in kilobits per
                     second or packets per second, depending on the meter
                     flags defined above.

              burst_size=size
                     The maximum burst allowed for the band.  If pktps is
                     specified, then size is a packet count, otherwise it is
                     in kilobits.  If unspecified, the switch is free to
                     select some reasonable value depending on its
                     configuration.

OPTIONS         top

       --strict
              Uses strict matching when running flow modification commands.

       --names
       --no-names
              Every OpenFlow port has a name and a number.  By default,
              ovs-ofctl commands accept both port names and numbers, and
              they display port names if ovs-ofctl is running on an
              interactive console, port numbers otherwise.  With --names,
              ovs-ofctl commands both accept and display port names; with
              --no-names, commands neither accept nor display port names.

              If a port name contains special characters or might be
              confused with a keyword within a flow, it may be enclosed in
              double quotes (escaped from the shell).  If necessary, JSON-
              style escape sequences may be used inside quotes, as specified
              in RFC 7159.  When it displays port names, ovs-ofctl quotes
              any name that does not start with a letter followed by letters
              or digits.

              These options are new in Open vSwitch 2.8.  Earlier versions
              always behaved as if --no-names were specified.

              Open vSwitch does not place its own limit on the length of
              port names, but OpenFlow 1.0 to 1.5 limit port names to 15
              bytes and OpenFlow 1.6 limits them to 63 bytes.  Because
              ovs-ofctl uses OpenFlow to retrieve the mapping between port
              names and numbers, names longer than this limit will be
              truncated for both display and acceptance.  Truncation can
              also cause long names that are different to appear to be the
              same; when a switch has two ports with the same (truncated)
              name, ovs-ofctl refuses to display or accept the name, using
              the number instead.

       --stats
       --no-stats
              The dump-flows command by default, or with --stats, includes
              flow duration, packet and byte counts, and idle and hard age
              in its output.  With --no-stats, it omits all of these, as
              well as cookie values and table IDs if they are zero.

       --read-only
              Do not execute read/write commands.

       --bundle
              Execute flow mods as an OpenFlow 1.4 atomic bundle
              transaction.

              ·      Within a bundle, all flow mods are processed in the
                     order they appear and as a single atomic transaction,
                     meaning that if one of them fails, the whole
                     transaction fails and none of the changes are made to
                     the switch's flow table, and that each given datapath
                     packet traversing the OpenFlow tables sees the flow
                     tables either as before the transaction, or after all
                     the flow mods in the bundle have been successfully
                     applied.

              ·      The beginning and the end of the flow table
                     modification commands in a bundle are delimited with
                     OpenFlow 1.4 bundle control messages, which makes it
                     possible to stream the included commands without
                     explicit OpenFlow barriers, which are otherwise used
                     after each flow table modification command.  This may
                     make large modifications execute faster as a bundle.

              ·      Bundles require OpenFlow 1.4 or higher.  An explicit -O
                     OpenFlow14 option is not needed, but you may need to
                     enable OpenFlow 1.4 support for OVS by setting the
                     OVSDB protocols column in the bridge table.

       -O [version[,version]...]
       --protocols=[version[,version]...]
              Sets the OpenFlow protocol versions that are allowed when
              establishing an OpenFlow session.

              These protocol versions are enabled by default:

              ·      OpenFlow10, for OpenFlow 1.0.
       The following protocol versions are generally supported, but for
       compatibility with older versions of Open vSwitch they are not
       enabled by default:

              ·      OpenFlow11, for OpenFlow 1.1.

              ·      OpenFlow12, for OpenFlow 1.2.

              ·      OpenFlow13, for OpenFlow 1.3.

              ·      OpenFlow14, for OpenFlow 1.4.

              Support for the following protocol versions is provided for
              testing and development purposes.  They are not enabled by
              default:

              ·      OpenFlow15, for OpenFlow 1.5.

              ·      OpenFlow16, for OpenFlow 1.6.

       -F format[,format...]
       --flow-format=format[,format...]
              ovs-ofctl supports the following individual flow formats, any
              number of which may be listed as format:

              OpenFlow10-table_id
                     This is the standard OpenFlow 1.0 flow format.  All
                     OpenFlow switches and all versions of Open vSwitch
                     support this flow format.

              OpenFlow10+table_id
                     This is the standard OpenFlow 1.0 flow format plus a
                     Nicira extension that allows ovs-ofctl to specify the
                     flow table in which a particular flow should be placed.
                     Open vSwitch 1.2 and later supports this flow format.

              NXM-table_id (Nicira Extended Match)
                     This Nicira extension to OpenFlow is flexible and
                     extensible.  It supports all of the Nicira flow
                     extensions, such as tun_id and registers.  Open vSwitch
                     1.1 and later supports this flow format.

              NXM+table_id (Nicira Extended Match)
                     This combines Nicira Extended match with the ability to
                     place a flow in a specific table.  Open vSwitch 1.2 and
                     later supports this flow format.

              OXM-OpenFlow12
              OXM-OpenFlow13
              OXM-OpenFlow14
              OXM-OpenFlow15
              OXM-OpenFlow16
                     These are the standard OXM (OpenFlow Extensible Match)
                     flow format in OpenFlow 1.2 and later.

              ovs-ofctl also supports the following abbreviations for
              collections of flow formats:

              any    Any supported flow format.

              OpenFlow10
                     OpenFlow10-table_id or OpenFlow10+table_id.

              NXM    NXM-table_id or NXM+table_id.

              OXM    OXM-OpenFlow12, OXM-OpenFlow13, or OXM-OpenFlow14.

              For commands that modify the flow table, ovs-ofctl by default
              negotiates the most widely supported flow format that supports
              the flows being added.  For commands that query the flow
              table, ovs-ofctl by default uses the most advanced format
              supported by the switch.

              This option, where format is a comma-separated list of one or
              more of the formats listed above, limits ovs-ofctl's choice of
              flow format.  If a command cannot work as requested using one
              of the specified flow formats, ovs-ofctl will report a fatal
              error.

       -P format
       --packet-in-format=format
              ovs-ofctl supports the following ``packet-in'' formats, in
              order of increasing capability:

              standard
                     This uses the OFPT_PACKET_IN message, the standard
                     ``packet-in'' message for any given OpenFlow version.
                     Every OpenFlow switch that supports a given OpenFlow
                     version supports this format.

              nxt_packet_in
                     This uses the NXT_PACKET_IN message, which adds many of
                     the capabilities of the OpenFlow 1.1 and later
                     ``packet-in'' messages before those OpenFlow versions
                     were available in Open vSwitch.  Open vSwitch 1.1 and
                     later support this format.  Only Open vSwitch 2.6 and
                     later, however, support it for OpenFlow 1.1 and later
                     (but there is little reason to use it with those
                     versions of OpenFlow).

              nxt_packet_in2
                     This uses the NXT_PACKET_IN2 message, which is
                     extensible and should avoid the need to define new
                     formats later.  In particular, this format supports
                     passing arbitrary user-provided data to a controller
                     using the userdata option on the controller action.
                     Open vSwitch 2.6 and later support this format.

              Without this option, ovs-ofctl prefers nxt_packet_in2 if the
              switch supports it.  Otherwise, if OpenFlow 1.0 is in use,
              ovs-ofctl prefers nxt_packet_in if the switch supports it.
              Otherwise, ovs-ofctl falls back to the standard packet-in
              format.  When this option is specified, ovs-ofctl insists on
              the selected format.  If the switch does not support the
              requested format, ovs-ofctl will report a fatal error.

              Before version 2.6, Open vSwitch called standard format
              openflow10 and nxt_packet_in format nxm, and ovs-ofctl still
              accepts these names as synonyms.  (The name openflow10 was a
              misnomer because this format actually varies from one OpenFlow
              version to another; it is not consistently OpenFlow 1.0
              format.  Similarly, when nxt_packet_in2 was introduced, the
              name nxm became confusing because it also uses OXM/NXM.)

              This option affects only the monitor command.

       --timestamp
              Print a timestamp before each received packet.  This option
              only affects the monitor, snoop, and ofp-parse-pcap commands.

       -m
       --more Increases the verbosity of OpenFlow messages printed and
              logged by ovs-ofctl commands.  Specify this option more than
              once to increase verbosity further.

       --sort[=field]
       --rsort[=field]
              Display output sorted by flow field in ascending (--sort) or
              descending (--rsort) order, where field is any of the fields
              that are allowed for matching or priority to sort by priority.
              When field is omitted, the output is sorted by priority.
              Specify these options multiple times to sort by multiple
              fields.

              Any given flow will not necessarily specify a value for a
              given field.  This requires special treatement:

              ·      A flow that does not specify any part of a field that
                     is used for sorting is sorted after all the flows that
                     do specify the field.  For example, --sort=tcp_src will
                     sort all the flows that specify a TCP source port in
                     ascending order, followed by the flows that do not
                     specify a TCP source port at all.

              ·      A flow that only specifies some bits in a field is
                     sorted as if the wildcarded bits were zero.  For
                     example, --sort=nw_src would sort a flow that specifies
                     nw_src=192.168.0.0/24 the same as nw_src=192.168.0.0.

              These options currently affect only dump-flows output.

   Daemon Options
       The following options are valid on POSIX based platforms.

       --pidfile[=pidfile]
              Causes a file (by default, ovs-ofctl.pid) to be created
              indicating the PID of the running process.  If the pidfile
              argument is not specified, or if it does not begin with /,
              then it is created in /usr/local/var/run/openvswitch.

              If --pidfile is not specified, no pidfile is created.

       --overwrite-pidfile
              By default, when --pidfile is specified and the specified
              pidfile already exists and is locked by a running process,
              ovs-ofctl refuses to start.  Specify --overwrite-pidfile to
              cause it to instead overwrite the pidfile.

              When --pidfile is not specified, this option has no effect.

       --detach
              Runs ovs-ofctl as a background process.  The process forks,
              and in the child it starts a new session, closes the standard
              file descriptors (which has the side effect of disabling
              logging to the console), and changes its current directory to
              the root (unless --no-chdir is specified).  After the child
              completes its initialization, the parent exits.  ovs-ofctl
              detaches only when executing the monitor or snoop commands.

       --monitor
              Creates an additional process to monitor the ovs-ofctl daemon.
              If the daemon dies due to a signal that indicates a
              programming error (SIGABRT, SIGALRM, SIGBUS, SIGFPE, SIGILL,
              SIGPIPE, SIGSEGV, SIGXCPU, or SIGXFSZ) then the monitor
              process starts a new copy of it.  If the daemon dies or exits
              for another reason, the monitor process exits.

              This option is normally used with --detach, but it also
              functions without it.

       --no-chdir
              By default, when --detach is specified, ovs-ofctl changes its
              current working directory to the root directory after it
              detaches.  Otherwise, invoking ovs-ofctl from a carelessly
              chosen directory would prevent the administrator from
              unmounting the file system that holds that directory.

              Specifying --no-chdir suppresses this behavior, preventing
              ovs-ofctl from changing its current working directory.  This
              may be useful for collecting core files, since it is common
              behavior to write core dumps into the current working
              directory and the root directory is not a good directory to
              use.

              This option has no effect when --detach is not specified.

       --no-self-confinement
              By default daemon will try to self-confine itself to work with
              files under well-know, at build-time whitelisted directories.
              It is better to stick with this default behavior and not to
              use this flag unless some other Access Control is used to
              confine daemon.  Note that in contrast to other access control
              implementations that are typically enforced from kernel-space
              (e.g. DAC or MAC), self-confinement is imposed from the user-
              space daemon itself and hence should not be considered as a
              full confinement strategy, but instead should be viewed as an
              additional layer of security.

       --user Causes ovs-ofctl to run as a different user specified in
              "user:group", thus dropping most of the root privileges. Short
              forms "user" and ":group" are also allowed, with current user
              or group are assumed respectively. Only daemons started by the
              root user accepts this argument.

              On Linux, daemons will be granted CAP_IPC_LOCK and
              CAP_NET_BIND_SERVICES before dropping root privileges. Daemons
              that interact with a datapath, such as ovs-vswitchd, will be
              granted two additional capabilities, namely CAP_NET_ADMIN and
              CAP_NET_RAW. The capability change will apply even if new user
              is "root".

              On Windows, this option is not currently supported. For
              security reasons, specifying this option will cause the daemon
              process not to start.

       --unixctl=socket
              Sets the name of the control socket on which ovs-ofctl listens
              for runtime management commands (see RUNTIME MANAGEMENT
              COMMANDS, below).  If socket does not begin with /, it is
              interpreted as relative to /usr/local/var/run/openvswitch.  If
              --unixctl is not used at all, the default socket is
              /usr/local/var/run/openvswitch/ovs-ofctl.pid.ctl, where pid is
              ovs-ofctl's process ID.

              On Windows a local named pipe is used to listen for runtime
              management commands.  A file is created in the absolute path
              as pointed by socket or if --unixctl is not used at all, a
              file is created as ovs-ofctl.ctl in the configured OVS_RUNDIR
              directory.  The file exists just to mimic the behavior of a
              Unix domain socket.

              Specifying none for socket disables the control socket
              feature.

   Public Key Infrastructure Options
       -p privkey.pem
       --private-key=privkey.pem
              Specifies a PEM file containing the private key used as
              ovs-ofctl's identity for outgoing SSL connections.

       -c cert.pem
       --certificate=cert.pem
              Specifies a PEM file containing a certificate that certifies
              the private key specified on -p or --private-key to be
              trustworthy.  The certificate must be signed by the
              certificate authority (CA) that the peer in SSL connections
              will use to verify it.

       -C cacert.pem
       --ca-cert=cacert.pem
              Specifies a PEM file containing the CA certificate that
              ovs-ofctl should use to verify certificates presented to it by
              SSL peers.  (This may be the same certificate that SSL peers
              use to verify the certificate specified on -c or
              --certificate, or it may be a different one, depending on the
              PKI design in use.)

       -C none
       --ca-cert=none
              Disables verification of certificates presented by SSL peers.
              This introduces a security risk, because it means that
              certificates cannot be verified to be those of known trusted
              hosts.

       -v[spec]
       --verbose=[spec]
              Sets logging levels.  Without any spec, sets the log level for
              every module and destination to dbg.  Otherwise, spec is a
              list of words separated by spaces or commas or colons, up to
              one from each category below:

              ·      A valid module name, as displayed by the vlog/list
                     command on ovs-appctl(8), limits the log level change
                     to the specified module.

              ·      syslog, console, or file, to limit the log level change
                     to only to the system log, to the console, or to a
                     file, respectively.  (If --detach is specified,
                     ovs-ofctl closes its standard file descriptors, so
                     logging to the console will have no effect.)

                     On Windows platform, syslog is accepted as a word and
                     is only useful along with the --syslog-target option
                     (the word has no effect otherwise).

              ·      off, emer, err, warn, info, or dbg, to control the log
                     level.  Messages of the given severity or higher will
                     be logged, and messages of lower severity will be
                     filtered out.  off filters out all messages.  See
                     ovs-appctl(8) for a definition of each log level.

              Case is not significant within spec.

              Regardless of the log levels set for file, logging to a file
              will not take place unless --log-file is also specified (see
              below).

              For compatibility with older versions of OVS, any is accepted
              as a word but has no effect.

       -v
       --verbose
              Sets the maximum logging verbosity level, equivalent to
              --verbose=dbg.

       -vPATTERN:destination:pattern
       --verbose=PATTERN:destination:pattern
              Sets the log pattern for destination to pattern.  Refer to
              ovs-appctl(8) for a description of the valid syntax for
              pattern.

       -vFACILITY:facility
       --verbose=FACILITY:facility
              Sets the RFC5424 facility of the log message. facility can be
              one of kern, user, mail, daemon, auth, syslog, lpr, news,
              uucp, clock, ftp, ntp, audit, alert, clock2, local0, local1,
              local2, local3, local4, local5, local6 or local7. If this
              option is not specified, daemon is used as the default for the
              local system syslog and local0 is used while sending a message
              to the target provided via the --syslog-target option.

       --log-file[=file]
              Enables logging to a file.  If file is specified, then it is
              used as the exact name for the log file.  The default log file
              name used if file is omitted is
              /usr/local/var/log/openvswitch/ovs-ofctl.log.

       --syslog-target=host:port
              Send syslog messages to UDP port on host, in addition to the
              system syslog.  The host must be a numerical IP address, not a
              hostname.

       --syslog-method=method
              Specify method how syslog messages should be sent to syslog
              daemon.  Following forms are supported:

              ·      libc, use libc syslog() function.  This is the default
                     behavior.  Downside of using this options is that libc
                     adds fixed prefix to every message before it is
                     actually sent to the syslog daemon over /dev/log UNIX
                     domain socket.

              ·      unix:file, use UNIX domain socket directly.  It is
                     possible to specify arbitrary message format with this
                     option.  However, rsyslogd 8.9 and older versions use
                     hard coded parser function anyway that limits UNIX
                     domain socket use.  If you want to use arbitrary
                     message format with older rsyslogd versions, then use
                     UDP socket to localhost IP address instead.

              ·      udp:ip:port, use UDP socket.  With this method it is
                     possible to use arbitrary message format also with
                     older rsyslogd.  When sending syslog messages over UDP
                     socket extra precaution needs to be taken into account,
                     for example, syslog daemon needs to be configured to
                     listen on the specified UDP port, accidental iptables
                     rules could be interfering with local syslog traffic
                     and there are some security considerations that apply
                     to UDP sockets, but do not apply to UNIX domain
                     sockets.

       --color[=when]
              Colorize the output (for some commands); when can be never,
              always, or auto (the default).

              Only some commands support output coloring.  Color names and
              default colors may change in future releases.

              The environment variable OVS_COLORS can be used to specify
              user-defined colors and other attributes used to highlight
              various parts of the output. If set, its value is a colon-
              separated list of capabilities that defaults to
              ac:01;31:dr=34:le=31:pm=36:pr=35:sp=33:vl=32. Supported
              capabilities were initially designed for coloring flows from
              ovs-ofctl dump-flows switch command, and they are as follows.

                     ac=01;31
                            SGR substring for actions= keyword in a flow.
                            The default is a bold red text foreground.

                     dr=34  SGR substring for drop keyword.  The default is
                            a dark blue text foreground.

                     le=31  SGR substring for learn= keyword in a flow.  The
                            default is a red text foreground.

                     pm=36  SGR substring for flow match attribute names.
                            The default is a cyan text foreground.

                     pr=35  SGR substring for keywords in a flow that are
                            followed by arguments inside parenthesis.  The
                            default is a magenta text foreground.

                     sp=33  SGR substring for some special keywords in a
                            flow, notably: table=, priority=, load:,
                            output:, move:, group:, CONTROLLER:, set_field:,
                            resubmit:, exit.  The default is a yellow text
                            foreground.

                     vl=32  SGR substring for a lone flow match attribute
                            with no field name.  The default is a green text
                            foreground.

              See the Select Graphic Rendition (SGR) section in the
              documentation of the text terminal that is used for permitted
              values and their meaning as character attributes.

       -h
       --help Prints a brief help message to the console.

       -V
       --version
              Prints version information to the console.

RUNTIME MANAGEMENT COMMANDS         top

       ovs-appctl(8) can send commands to a running ovs-ofctl process.  The
       supported commands are listed below.

       exit   Causes ovs-ofctl to gracefully terminate.  This command
              applies only when executing the monitor or snoop commands.

       ofctl/set-output-file file
              Causes all subsequent output to go to file instead of stderr.
              This command applies only when executing the monitor or snoop
              commands.

       ofctl/send ofmsg...
              Sends each ofmsg, specified as a sequence of hex digits that
              express an OpenFlow message, on the OpenFlow connection.  This
              command is useful only when executing the monitor command.

       ofctl/packet-out packet-out
              Sends an OpenFlow PACKET_OUT message specified in Packet-Out
              Syntax, on the OpenFlow connection.  See Packet-Out Syntax
              section for more information.  This command is useful only
              when executing the monitor command.

       ofctl/barrier
              Sends an OpenFlow barrier request on the OpenFlow connection
              and waits for a reply.  This command is useful only for the
              monitor command.

EXAMPLES         top

       The following examples assume that ovs-vswitchd has a bridge named
       br0 configured.

       ovs-ofctl dump-tables br0
              Prints out the switch's table stats.  (This is more
              interesting after some traffic has passed through.)

       ovs-ofctl dump-flows br0
              Prints the flow entries in the switch.

       ovs-ofctl add-flow table=0 actions=learn(table=1,hard_timeout=10,
       NXM_OF_VLAN_TCI[0..11],output:NXM_OF_IN_PORT[]), resubmit(,1)
              ovs-ofctl add-flow  table=1 priority=0 actions=flood
              Implements a level 2 MAC learning switch using the learn.

       ovs-ofctl add-flow br0 'table=0,priority=0
       actions=load:3->NXM_NX_REG0[0..15],learn(table=0,priority=1,idle_timeout=10,NXM_OF_ETH_SRC[],NXM_OF_VLAN_TCI[0..11],output:NXM_NX_REG0[0..15]),output:2
              In this use of a learn action, the first packet from each
              source MAC will be sent to port 2. Subsequent packets will be
              output to port 3, with an idle timeout of 10 seconds.  NXM
              field names and match field names are both accepted, e.g.
              NXM_NX_REG0 or reg0 for the first register, and empty brackets
              may be omitted.

              Additional examples may be found documented as part of related
              sections.

SEE ALSO         top

       ovs-fields(7), ovs-appctl(8), ovs-vswitchd(8),
       ovs-vswitchd.conf.db(8)

COLOPHON         top

       This page is part of the Open vSwitch (a distributed virtual
       multilayer switch) project.  Information about the project can be
       found at ⟨http://openvswitch.org/⟩.  If you have a bug report for
       this manual page, send it to bugs@openvswitch.org.  This page was
       obtained from the project's upstream Git repository
       ⟨https://github.com/openvswitch/ovs.git⟩ on 2018-02-02.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2018-02-01.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to man-pages@man7.org

Open vSwitch                       2.8.90                       ovs-ofctl(8)

Pages that refer to this page: ovs-vswitchd.conf.db(5)ovs-fields(7)ovn-sbctl(8)ovn-trace(8)ovs-dpctl(8)ovs-l3ping(8)ovs-testcontroller(8)ovs-vswitchd(8)