Implement OpenFlow 1.4+ OFPTC_EVICTION.

[cascardo/ovs.git] / utilities / ovs-ofctl.8.in

.\" -*- nroff -*-
.de IQ
.  br
.  ns
.  IP "\\$1"
..
.TH ovs\-ofctl 8 "@VERSION@" "Open vSwitch" "Open vSwitch Manual"
.ds PN ovs\-ofctl
.
.SH NAME
ovs\-ofctl \- administer OpenFlow switches
.
.SH SYNOPSIS
.B ovs\-ofctl
[\fIoptions\fR] \fIcommand \fR[\fIswitch\fR] [\fIargs\fR\&...]
.
.SH DESCRIPTION
The
.B 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.
.
.SS "OpenFlow Switch Management Commands"
.PP
These commands allow \fBovs\-ofctl\fR to monitor and administer an OpenFlow
switch.  It is able to show the current state of a switch, including
features, configuration, and table entries.
.PP
Most of these commands take an argument that specifies the method for
connecting to an OpenFlow switch.  The following connection methods
are supported:
.
.RS
.so lib/vconn-active.man
.
.IP "\fIfile\fR"
This is short for \fBunix:\fIfile\fR, as long as \fIfile\fR does not
contain a colon.
.
.IP \fIbridge\fR
This is short for \fBunix:@RUNDIR@/\fIbridge\fB.mgmt\fR, as long as
\fIbridge\fR does not contain a colon.
.
.IP [\fItype\fB@\fR]\fIdp\fR
Attempts to look up the bridge associated with \fIdp\fR and open as
above.  If \fItype\fR is given, it specifies the datapath provider of
\fIdp\fR, otherwise the default provider \fBsystem\fR is assumed.
.RE
.
.TP
\fBshow \fIswitch\fR
Prints to the console information on \fIswitch\fR, including
information on its flow tables and ports.
.
.TP
\fBdump\-tables \fIswitch\fR
Prints to the console statistics for each of the flow tables used by
\fIswitch\fR.
.TP
\fBdump\-table\-features \fIswitch\fR
Prints to the console features for each of the flow tables used by
\fIswitch\fR.
.IP "\fBmod\-table \fIswitch\fR \fItable_id\fR \fIsetting\fR"
This command configures flow table settings for OpenFlow table
\fItable_id\fR within \fIswitch\fR.  The available settings depend on
the OpenFlow version in use.  In OpenFlow 1.1 and 1.2 (which must be
enabled with the \fB\-O\fR option) only, \fBmod\-table\fR configures
behavior when no flow is found when a packet is looked up in a flow
table.  The following \fIsetting\fR values are available:
.RS
.IP \fBdrop\fR
Drop the packet.
.IP \fBcontinue\fR
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.)
.IP \fBcontroller\fR
Send to controller.  (This is how an OpenFlow 1.0 switch always
handles packets that do not match any flow in the last table.)
.RE
.IP
In OpenFlow 1.4 and later (which must be enabled with the \fB\-O\fR
option) only, \fBmod\-table\fR configures the behavior when a
controller attempts to add a flow to a flow table that is full.  The
following \fIsetting\fR values are available:
.RS
.IP \fBevict\fR
Delete some existing flow from the flow table, according to the
algorithm described for the \fBFlow_Table\fR table in
\fBovs-vswitchd.conf.db\fR(5).
.IP \fBnoevict\fR
Refuse to add the new flow.  (Eviction might still be enabled through
the \fBoverflow_policy\fR oclumn in the \fBFlow_Table\fR table
documented in \fBovs-vswitchd.conf.db\fR(5).)
.RE
.
.TP
\fBdump\-ports \fIswitch\fR [\fInetdev\fR]
Prints to the console statistics for network devices associated with 
\fIswitch\fR.  If \fInetdev\fR is specified, only the statistics
associated with that device will be printed.  \fInetdev\fR can be an
OpenFlow assigned port number or device name, e.g. \fBeth0\fR.
.
.IP "\fBdump\-ports\-desc \fIswitch\fR [\fIport\fR]"
Prints to the console detailed information about network devices
associated with \fIswitch\fR.  To dump only a specific port, specify
its number as \fIport\fR.  Otherwise, if \fIport\fR is omitted, or if
it is specified as \fBANY\fR, then all ports are printed.  This is a
subset of the information provided by the \fBshow\fR command.
.IP
If the connection to \fIswitch\fR 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).
.IP
Only OpenFlow 1.5 and later support dumping a specific port.  Earlier
versions of OpenFlow always dump all ports.
.
.IP "\fBmod\-port \fIswitch\fR \fIport\fR \fIaction\fR"
Modify characteristics of port \fBport\fR in \fIswitch\fR.  \fIport\fR
may be an OpenFlow port number or name or the keyword \fBLOCAL\fR (the
preferred way to refer to the OpenFlow local port).  The \fIaction\fR
may be any one of the following:
.
.RS
.IQ \fBup\fR
.IQ \fBdown\fR
Enable or disable the interface.  This is equivalent to \fBifconfig
up\fR or \fBifconfig down\fR on a Unix system.
.
.IP \fBstp\fR
.IQ \fBno\-stp\fR
Enable or disable 802.1D spanning tree protocol (STP) on the
interface.  OpenFlow implementations that don't support STP will
refuse to enable it.
.
.IP \fBreceive\fR
.IQ \fBno\-receive\fR
.IQ \fBreceive\-stp\fR
.IQ \fBno\-receive\-stp\fR
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
\fBreceive\fR or \fBno\-receive\fR setting applies to all packets
except 802.1D spanning tree packets, which are separately controlled
by \fBreceive\-stp\fR or \fBno\-receive\-stp\fR.
.
.IP \fBforward\fR
.IQ \fBno\-forward\fR
Allow or disallow forwarding of traffic to this interface.  By
default, forwarding is enabled.
.
.IP \fBflood\fR
.IQ \fBno\-flood\fR
Controls whether an OpenFlow \fBflood\fR 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.
.
.IP \fBpacket\-in\fR
.IQ \fBno\-packet\-in\fR
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.
.RE
.IP
The \fBshow\fR command displays (among other information) the
configuration that \fBmod\-port\fR changes.
.
.IP "\fBget\-frags \fIswitch\fR"
Prints \fIswitch\fR's fragment handling mode.  See \fBset\-frags\fR,
below, for a description of each fragment handling mode.
.IP
The \fBshow\fR command also prints the fragment handling mode among
its other output.
.
.IP "\fBset\-frags \fIswitch frag_mode\fR"
Configures \fIswitch\fR's treatment of IPv4 and IPv6 fragments.  The
choices for \fIfrag_mode\fR are:
.RS
.IP "\fBnormal\fR"
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.
.IP "\fBdrop\fR"
Fragments are dropped without passing through the flow table.
.IP "\fBreassemble\fR"
The switch reassembles fragments into full IP packets before passing
them through the flow table.  Open vSwitch does not implement this
fragment handling mode.
.IP "\fBnx\-match\fR"
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.
.RE
.IP
See the description of \fBip_frag\fR, below, for a way to match on
whether a packet is a fragment and on its fragment offset.
.
.TP
\fBdump\-flows \fIswitch \fR[\fIflows\fR]
Prints to the console all flow entries in \fIswitch\fR's
tables that match \fIflows\fR.  If \fIflows\fR is omitted, all flows
in the switch are retrieved.  See \fBFlow Syntax\fR, below, for the
syntax of \fIflows\fR.  The output format is described in
\fBTable Entry Output\fR.
.
.IP
By default, \fBovs\-ofctl\fR prints flow entries in the same order
that the switch sends them, which is unlikely to be intuitive or
consistent.  See the description of \fB\-\-sort\fR and \fB\-\-rsort\fR,
under \fBOPTIONS\fR below, to influence the display order.
.
.TP
\fBdump\-aggregate \fIswitch \fR[\fIflows\fR]
Prints to the console aggregate statistics for flows in
\fIswitch\fR's tables that match \fIflows\fR.  If \fIflows\fR is omitted, 
the statistics are aggregated across all flows in the switch's flow
tables.  See \fBFlow Syntax\fR, below, for the syntax of \fIflows\fR.
The output format is described in \fBTable Entry Output\fR.
.
.IP "\fBqueue\-stats \fIswitch \fR[\fIport \fR[\fIqueue\fR]]"
Prints to the console statistics for the specified \fIqueue\fR on
\fIport\fR within \fIswitch\fR.  \fIport\fR can be an OpenFlow port
number or name, the keyword \fBLOCAL\fR (the preferred way to refer to
the OpenFlow local port), or the keyword \fBALL\fR.  Either of
\fIport\fR or \fIqueue\fR or both may be omitted (or equivalently the
keyword \fBALL\fR).  If both are omitted, statistics are printed for
all queues on all ports.  If only \fIqueue\fR is omitted, then
statistics are printed for all queues on \fIport\fR; if only
\fIport\fR is omitted, then statistics are printed for \fIqueue\fR on
every port where it exists.
.
.SS "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 \fBovs\-ofctl\fR (using \fB\-O\fR) and in
the switch itself (with the \fBprotocols\fR column in the \fBBridge\fR
table).  For more information, see ``Q: What versions of OpenFlow does
Open vSwitch support?'' in the Open vSwitch FAQ.
.
.IP "\fBdump\-groups \fIswitch\fR [\fIgroup\fR]"
Prints group entries in \fIswitch\fR's tables to console.  To dump
only a specific group, specify its number as \fIgroup\fR.  Otherwise,
if \fIgroup\fR is omitted, or if it is specified as \fBALL\fR, then
all groups are printed.  Each line of output is a group entry as
described in \fBGroup Syntax\fR below.
.IP
Only OpenFlow 1.5 and later support dumping a specific group.  Earlier
versions of OpenFlow always dump all groups.
.
.IP "\fBdump\-group\-features \fIswitch"
Prints to the console the group features of the \fIswitch\fR.
.
.IP "\fBdump\-group-stats \fIswitch \fR[\fIgroups\fR]"
Prints to the console statistics for the specified \fIgroups in the
\fIswitch\fR's tables.  If \fIgroups\fR is omitted then statistics for all
groups are printed.  See \fBGroup Syntax\fR, below, for the syntax of
\fIgroups\fR.
.
.SS "OpenFlow 1.3+ Switch Meter Table Commands"
.
These commands manage the meter table in an OpenFlow switch.  In each
case, \fImeter\fR specifies a meter entry in the format described in
\fBMeter Syntax\fR, below.
.
.PP
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.
.
.IP "\fBadd\-meter \fIswitch meter\fR"
Add a meter entry to \fIswitch\fR's tables. The \fImeter\fR syntax is
described in section \fBMeter Syntax\fR, below.
.
.IP "\fBmod\-meter \fIswitch meter\fR"
Modify an existing meter.
.
.IP "\fBdel\-meters \fIswitch\fR"
.IQ "\fBdel\-meter \fIswitch\fR [\fImeter\fR]"
Delete entries from \fIswitch\fR's meter table.  \fImeter\fR can specify
a single meter with syntax \fBmeter=\fIid\fR, or all meters with syntax
\fBmeter=all\fR.
.
.IP "\fBdump\-meters \fIswitch\fR"
.IQ "\fBdump\-meter \fIswitch\fR [\fImeter\fR]"
Print meter configuration.  \fImeter\fR can specify a single meter with
syntax \fBmeter=\fIid\fR, or all meters with syntax \fBmeter=all\fR.
.
.IP "\fBmeter\-stats \fIswitch\fR [\fImeter\fR]"
Print meter statistics.  \fImeter\fR can specify a single meter with
syntax \fBmeter=\fIid\fR, or all meters with syntax \fBmeter=all\fR.
.
.IP "\fBmeter\-features \fIswitch\fR"
Print meter features.
.
.SS "OpenFlow Switch Flow Table Commands"
.
These commands manage the flow table in an OpenFlow switch.  In each
case, \fIflow\fR specifies a flow entry in the format described in
\fBFlow Syntax\fR, below, \fIfile\fR is a text file that contains zero
or more flows in the same syntax, one per line, and the optional
\fB\-\-bundle\fR option operates the command as a single atomic
transation, see option \fB\-\-bundle\fR, below.
.
.IP "[\fB\-\-bundle\fR] \fBadd\-flow \fIswitch flow\fR"
.IQ "[\fB\-\-bundle\fR] \fBadd\-flow \fIswitch \fB\- < \fIfile\fR"
.IQ "[\fB\-\-bundle\fR] \fBadd\-flows \fIswitch file\fR"
Add each flow entry to \fIswitch\fR's tables.
.
Each flow specification (e.g., each line in \fIfile\fR) may start with
\fBadd\fR, \fBmodify\fR, \fBdelete\fR, \fBmodify_strict\fR, or
\fBdelete_strict\fR 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.
.
.IP "[\fB\-\-bundle\fR] [\fB\-\-strict\fR] \fBmod\-flows \fIswitch flow\fR"
.IQ "[\fB\-\-bundle\fR] [\fB\-\-strict\fR] \fBmod\-flows \fIswitch \fB\- < \fIfile\fR"
Modify the actions in entries from \fIswitch\fR's tables that match
the specified flows.  With \fB\-\-strict\fR, wildcards are not treated
as active for matching purposes.
.
.IP "[\fB\-\-bundle\fR] \fBdel\-flows \fIswitch\fR"
.IQ "[\fB\-\-bundle\fR] [\fB\-\-strict\fR] \fBdel\-flows \fIswitch \fR[\fIflow\fR]"
.IQ "[\fB\-\-bundle\fR] [\fB\-\-strict\fR] \fBdel\-flows \fIswitch \fB\- < \fIfile\fR"
Deletes entries from \fIswitch\fR's flow table.  With only a
\fIswitch\fR argument, deletes all flows.  Otherwise, deletes flow
entries that match the specified flows.  With \fB\-\-strict\fR,
wildcards are not treated as active for matching purposes.
.
.IP "[\fB\-\-bundle\fR] [\fB\-\-readd\fR] \fBreplace\-flows \fIswitch file\fR"
Reads flow entries from \fIfile\fR (or \fBstdin\fR if \fIfile\fR is
\fB\-\fR) and queries the flow table from \fIswitch\fR.  Then it fixes
up any differences, adding flows from \fIflow\fR that are missing on
\fIswitch\fR, deleting flows from \fIswitch\fR that are not in
\fIfile\fR, and updating flows in \fIswitch\fR whose actions, cookie,
or timeouts differ in \fIfile\fR.
.
.IP
With \fB\-\-readd\fR, \fBovs\-ofctl\fR adds all the flows from
\fIfile\fR, even those that exist with the same actions, cookie, and
timeout in \fIswitch\fR.  This resets all the flow packet and byte
counters to 0, which can be useful for debugging.
.
.IP "\fBdiff\-flows \fIsource1 source2\fR"
Reads flow entries from \fIsource1\fR and \fIsource2\fR and prints the
differences.  A flow that is in \fIsource1\fR but not in \fIsource2\fR
is printed preceded by a \fB\-\fR, and a flow that is in \fIsource2\fR
but not in \fIsource1\fR is printed preceded by a \fB+\fR.  If a flow
exists in both \fIsource1\fR and \fIsource2\fR with different actions,
cookie, or timeouts, then both versions are printed preceded by
\fB\-\fR and \fB+\fR, respectively.
.IP
\fIsource1\fR and \fIsource2\fR may each name a file or a switch.  If
a name begins with \fB/\fR or \fB.\fR, then it is considered to be a
file name.  A name that contains \fB:\fR is considered to be a switch.
Otherwise, it is a file if a file by that name exists, a switch if
not.
.IP
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.
.
.IP "\fBpacket\-out \fIswitch in_port actions packet\fR..."
Connects to \fIswitch\fR and instructs it to execute the OpenFlow
\fIactions\fR on each \fIpacket\fR.  Each \fBpacket\fR is specified as a
series of hex digits.  For the purpose of executing the
actions, the packets are considered to have arrived on \fIin_port\fR,
which may be an OpenFlow port number or name (e.g. \fBeth0\fR), the
keyword \fBLOCAL\fR (the preferred way to refer to the OpenFlow
``local'' port), or the keyword \fBNONE\fR to indicate that the packet
was generated by the switch itself.
.
.SS "OpenFlow Switch Group Table Commands"
.
These commands manage the group table in an OpenFlow switch.  In each
case, \fIgroup\fR specifies a group entry in the format described in
\fBGroup Syntax\fR, below, and \fIfile\fR is a text file that contains
zero or more groups in the same syntax, one per line.

.IP "\fBadd\-group \fIswitch group\fR"
.IQ "\fBadd\-group \fIswitch \fB\- < \fIfile\fR"
.IQ "\fBadd\-groups \fIswitch file\fR"
Add each group entry to \fIswitch\fR's tables.
.
.IP "\fBmod\-group \fIswitch group\fR"
.IQ "\fBmod\-group \fIswitch \fB\- < \fIfile\fR"
Modify the action buckets in entries from \fIswitch\fR's tables for
each group entry.
.
.IP "\fBdel\-groups \fIswitch\fR"
.IQ "\fBdel\-groups \fIswitch \fR[\fIgroup\fR]"
.IQ "\fBdel\-groups \fIswitch \fB\- < \fIfile\fR"
Deletes entries from \fIswitch\fR's group table.  With only a
\fIswitch\fR argument, deletes all groups.  Otherwise, deletes the group
for each group entry.
.
.IP "\fBinsert\-buckets \fIswitch group\fR"
.IQ "\fBinsert\-buckets \fIswitch \fB\- < \fIfile\fR"
Add buckets to an existing group present in the \fIswitch\fR's group table.
If no \fIcommand_bucket_id\fR is present in the group specification then all
buckets of the group are removed.
.
.IP "\fBremove\-buckets \fIswitch group\fR"
.IQ "\fBremove\-buckets \fIswitch \fB\- < \fIfile\fR"
Remove buckets to an existing group present in the \fIswitch\fR's group table.
If no \fIcommand_bucket_id\fR is present in the group specification then all
buckets of the group are removed.
.
.SS "OpenFlow Switch Geneve Option Table Commands"
.
In order to work with Geneve options, it is necessary to maintain a mapping
table between an option (defined by <class, type, length>) and an NXM field
that can be operated on for the purposes of matches, actions, etc. This
mapping must be explicitly specified by the user through the following
commands. The format for \fIoptions\fR is given in \fBOption Syntax\fR below.

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

Currently, the Geneve mapping table is shared between all OpenFlow
switches in a given instance of Open vSwitch. This restriction will
be lifted in the future to allow for easier management.

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

.IP "\fBadd\-geneve\-map \fIswitch options\fR"
Add each option entry to \fIswitch\fR's tables. Duplicate fields are
rejected.
.
.IP "\fBdel\-geneve\-map \fIswitch \fR[\fIoptions\fR]"
Delete each option entry in \fIswitch\fR's tables based on its field index.
Fields that aren't already mapped will be ignored. If no options are
specified then the entire table will be cleared.
.
.IP "\fBdump\-geneve\-map \fIswitch\fR"
Show the currently mapped fields in the switch's option table as well
as switch capabilities.
.
.IP "\fBOption Syntax\fR"
\fB{class=\fIclass\fB,type=\fItype\fB,len=\fIlength\fB}->tun_metadata\fIn\fR

An option can be specified in this form (repeating as necessary and
separated by commas). For example, the follow is used to map a new option:

.RS
add-geneve-map br0 "{class=0xffff,type=0,len=4}->tun_metadata0"
.RE
.
.SS "OpenFlow Switch Monitoring Commands"
.
.IP "\fBsnoop \fIswitch\fR"
Connects to \fIswitch\fR and prints to the console all OpenFlow
messages received.  Unlike other \fBovs\-ofctl\fR commands, if
\fIswitch\fR is the name of a bridge, then the \fBsnoop\fR command
connects to a Unix domain socket named
\fB@RUNDIR@/\fIbridge\fB.snoop\fR.  \fBovs\-vswitchd\fR 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.
.IP
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.
.IP
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.
.
.IP "\fBmonitor \fIswitch\fR [\fImiss-len\fR] [\fBinvalid_ttl\fR] [\fBwatch:\fR[\fIspec\fR...]]"
Connects to \fIswitch\fR and prints to the console all OpenFlow
messages received.  Usually, \fIswitch\fR should specify the name of a
bridge in the \fBovs\-vswitchd\fR database.
.IP
If \fImiss-len\fR is provided, \fBovs\-ofctl\fR sends an OpenFlow ``set
configuration'' message at connection setup time that requests
\fImiss-len\fR bytes of each packet that misses the flow table.  Open vSwitch
does not send these and other asynchronous messages to an
\fBovs\-ofctl monitor\fR client connection unless a nonzero value is
specified on this argument.  (Thus, if \fImiss\-len\fR is not
specified, very little traffic will ordinarily be printed.)
.IP
If \fBinvalid_ttl\fR is passed, \fBovs\-ofctl\fR sends an OpenFlow ``set
configuration'' message at connection setup time that requests
\fBINVALID_TTL_TO_CONTROLLER\fR, so that \fBovs\-ofctl monitor\fR can
receive ``packet-in'' messages when TTL reaches zero on \fBdec_ttl\fR action.
.IP
\fBwatch:\fR[\fB\fIspec\fR...] causes \fBovs\-ofctl\fR 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 \fIspec\fR syntax is available:
.RS
.IP "\fB!initial\fR"
Do not report the switch's initial flow table contents.
.IP "\fB!add\fR"
Do not report newly added flows.
.IP "\fB!delete\fR"
Do not report deleted flows.
.IP "\fB!modify\fR"
Do not report modifications to existing flows.
.IP "\fB!own\fR"
Abbreviate changes made to the flow table by \fBovs\-ofctl\fR's own
connection to the switch.  (These could only occur using the
\fBofctl/send\fR command described below under \fBRUNTIME MANAGEMENT
COMMANDS\fR.)
.IP "\fB!actions\fR"
Do not report actions as part of flow updates.
.IP "\fBtable=\fInumber\fR"
Limits the monitoring to the table with the given \fInumber\fR between
0 and 254.  By default, all tables are monitored.
.IP "\fBout_port=\fIport\fR"
If set, only flows that output to \fIport\fR are monitored.  The
\fIport\fR may be an OpenFlow port number or keyword
(e.g. \fBLOCAL\fR).
.IP "\fIfield\fB=\fIvalue\fR"
Monitors only flows that have \fIfield\fR specified as the given
\fIvalue\fR.  Any syntax valid for matching on \fBdump\-flows\fR may
be used.
.RE
.IP
This command may be useful for debugging switch or controller
implementations.  With \fBwatch:\fR, it is particularly useful for
observing how a controller updates flow tables.
.
.SS "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.
.
.TP
\fBprobe \fItarget\fR
Sends a single OpenFlow echo-request message to \fItarget\fR and waits
for the response.  With the \fB\-t\fR or \fB\-\-timeout\fR option, this
command can test whether an OpenFlow switch or controller is up and
running.
.
.TP
\fBping \fItarget \fR[\fIn\fR]
Sends a series of 10 echo request packets to \fItarget\fR and times
each reply.  The echo request packets consist of an OpenFlow header
plus \fIn\fR bytes (default: 64) of randomly generated payload.  This
measures the latency of individual requests.
.
.TP
\fBbenchmark \fItarget n count\fR
Sends \fIcount\fR echo request packets that each consist of an
OpenFlow header plus \fIn\fR bytes of payload and waits for each
response.  Reports the total time required.  This is a measure of the
maximum bandwidth to \fItarget\fR for round-trips of \fIn\fR-byte
messages.
.
.SS "Other Commands"
.
.IP "\fBofp\-parse\fR \fIfile\fR"
Reads \fIfile\fR (or \fBstdin\fR if \fIfile\fR is \fB\-\fR) 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.
.
.IP "\fBofp\-parse\-pcap\fR \fIfile\fR [\fIport\fR...]"
Reads \fIfile\fR, which must be in the PCAP format used by network
capture tools such as \fBtcpdump\fR or \fBwireshark\fR, extracts all
the TCP streams for OpenFlow connections, and prints the OpenFlow
messages in those connections in human-readable format on
\fBstdout\fR.
.IP
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
\fIport\fR arguments to override the default.
.IP
This command cannot usefully print SSL encrypted traffic.  It does not
understand IPv6.
.
.SS "Flow Syntax"
.PP
Some \fBovs\-ofctl\fR commands accept an argument that describes a flow or
flows.  Such flow descriptions comprise a series
\fIfield\fB=\fIvalue\fR 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.)
.PP
Flow descriptions should be in \fBnormal form\fR.  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 \fBdl_type\fR is wildcarded, then L3
fields \fBnw_src\fR, \fBnw_dst\fR, and \fBnw_proto\fR must also be
wildcarded.  Similarly, if \fBdl_type\fR or \fBnw_proto\fR (the L3
protocol type) is wildcarded, so must be the L4 fields \fBtcp_dst\fR and
\fBtcp_src\fR.  \fBovs\-ofctl\fR will warn about
flows not in normal form.
.PP
The following field assignments describe how a flow matches a packet.
If any of these assignments is omitted from the flow syntax, the field
is treated as a wildcard; thus, if all of them are omitted, the
resulting flow matches all packets.  The string \fB*\fR may be specified
to explicitly mark any of these fields as a wildcard.
(\fB*\fR should be quoted to protect it from shell expansion.)
.
.IP \fBin_port=\fIport\fR
Matches OpenFlow port \fIport\fR, which may be an OpenFlow port number
or keyword (e.g. \fBLOCAL\fR).
\fBovs\-ofctl show\fR.
.IP
(The \fBresubmit\fR action can search OpenFlow flow tables with
arbitrary \fBin_port\fR values, so flows that match port numbers that
do not exist from an OpenFlow perspective can still potentially be
matched.)
.
.IP \fBdl_vlan=\fIvlan\fR
Matches IEEE 802.1q Virtual LAN tag \fIvlan\fR.  Specify \fB0xffff\fR
as \fIvlan\fR to match packets that are not tagged with a Virtual LAN;
otherwise, specify a number between 0 and 4095, inclusive, as the
12-bit VLAN ID to match.
.
.IP \fBdl_vlan_pcp=\fIpriority\fR
Matches IEEE 802.1q Priority Code Point (PCP) \fIpriority\fR, which is
specified as a value between 0 and 7, inclusive.  A higher value
indicates a higher frame priority level.
.
.IP \fBdl_src=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
.IQ \fBdl_dst=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
Matches an Ethernet source (or destination) address specified as 6
pairs of hexadecimal digits delimited by colons
(e.g. \fB00:0A:E4:25:6B:B0\fR).
.
.IP \fBdl_src=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB/\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
.IQ \fBdl_dst=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB/\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
Matches an Ethernet destination address specified as 6 pairs of
hexadecimal digits delimited by colons (e.g. \fB00:0A:E4:25:6B:B0\fR),
with a wildcard mask following the slash. Open vSwitch 1.8 and later
support arbitrary masks for source and/or destination. Earlier
versions only support masking the destination with the following masks:
.RS
.IP \fB01:00:00:00:00:00\fR
Match only the multicast bit.  Thus,
\fBdl_dst=01:00:00:00:00:00/01:00:00:00:00:00\fR matches all multicast
(including broadcast) Ethernet packets, and
\fBdl_dst=00:00:00:00:00:00/01:00:00:00:00:00\fR matches all unicast
Ethernet packets.
.IP \fBfe:ff:ff:ff:ff:ff\fR
Match all bits except the multicast bit.  This is probably not useful.
.IP \fBff:ff:ff:ff:ff:ff\fR
Exact match (equivalent to omitting the mask).
.IP \fB00:00:00:00:00:00\fR
Wildcard all bits (equivalent to \fBdl_dst=*\fR.)
.RE
.
.IP \fBdl_type=\fIethertype\fR
Matches Ethernet protocol type \fIethertype\fR, which is specified as an
integer between 0 and 65535, inclusive, either in decimal or as a 
hexadecimal number prefixed by \fB0x\fR (e.g. \fB0x0806\fR to match ARP 
packets).
.
.IP \fBnw_src=\fIip\fR[\fB/\fInetmask\fR]
.IQ \fBnw_dst=\fIip\fR[\fB/\fInetmask\fR]
When \fBdl_type\fR is 0x0800 (possibly via shorthand, e.g. \fBip\fR
or \fBtcp\fR), matches IPv4 source (or destination) address \fIip\fR,
which may be specified as an IP address or host name
(e.g. \fB192.168.1.1\fR or \fBwww.example.com\fR).  The optional
\fInetmask\fR allows restricting a match to an IPv4 address prefix.
The netmask may be specified as a dotted quad
(e.g. \fB192.168.1.0/255.255.255.0\fR) or as a CIDR block
(e.g. \fB192.168.1.0/24\fR).  Open vSwitch 1.8 and later support
arbitrary dotted quad masks; earlier versions support only CIDR masks,
that is, the dotted quads that are equivalent to some CIDR block.
.IP
When \fBdl_type=0x0806\fR or \fBarp\fR is specified, matches the
\fBar_spa\fR or \fBar_tpa\fR field, respectively, in ARP packets for
IPv4 and Ethernet.
.IP
When \fBdl_type=0x8035\fR or \fBrarp\fR is specified, matches the
\fBar_spa\fR or \fBar_tpa\fR field, respectively, in RARP packets for
IPv4 and Ethernet.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800,
0x0806, or 0x8035, the values of \fBnw_src\fR and \fBnw_dst\fR are ignored
(see \fBFlow Syntax\fR above).
.
.IP \fBnw_proto=\fIproto\fR
.IQ \fBip_proto=\fIproto\fR
When \fBip\fR or \fBdl_type=0x0800\fR is specified, matches IP
protocol type \fIproto\fR, which is specified as a decimal number
between 0 and 255, inclusive (e.g. 1 to match ICMP packets or 6 to match
TCP packets).
.IP
When \fBipv6\fR or \fBdl_type=0x86dd\fR is specified, matches IPv6
header type \fIproto\fR, which is specified as a decimal number between
0 and 255, inclusive (e.g. 58 to match ICMPv6 packets or 6 to match
TCP).  The header type is the terminal header as described in the
\fBDESIGN\fR document.
.IP
When \fBarp\fR or \fBdl_type=0x0806\fR is specified, matches the lower
8 bits of the ARP opcode.  ARP opcodes greater than 255 are treated as
0.
.IP
When \fBrarp\fR or \fBdl_type=0x8035\fR is specified, matches the lower
8 bits of the ARP opcode.  ARP opcodes greater than 255 are treated as
0.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800,
0x0806, 0x8035 or 0x86dd, the value of \fBnw_proto\fR is ignored (see
\fBFlow Syntax\fR above).
.
.IP \fBnw_tos=\fItos\fR
Matches IP ToS/DSCP or IPv6 traffic class field \fItos\fR, which is
specified as a decimal number between 0 and 255, inclusive.  Note that
the two lower reserved bits are ignored for matching purposes.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800 or
0x86dd, the value of \fBnw_tos\fR is ignored (see \fBFlow Syntax\fR
above).
.
.IP \fBip_dscp=\fIdscp\fR
Matches IP ToS/DSCP or IPv6 traffic class field \fIdscp\fR, which is
specified as a decimal number between 0 and 63, inclusive.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800 or
0x86dd, the value of \fBip_dscp\fR is ignored (see \fBFlow Syntax\fR
above).
.
.IP \fBnw_ecn=\fIecn\fR
.IQ \fBip_ecn=\fIecn\fR
Matches \fIecn\fR bits in IP ToS or IPv6 traffic class fields, which is
specified as a decimal number between 0 and 3, inclusive.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800 or
0x86dd, the value of \fBnw_ecn\fR is ignored (see \fBFlow Syntax\fR
above).
.
.IP \fBnw_ttl=\fIttl\fR
Matches IP TTL or IPv6 hop limit value \fIttl\fR, which is
specified as a decimal number between 0 and 255, inclusive.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800 or
0x86dd, the value of \fBnw_ttl\fR is ignored (see \fBFlow Syntax\fR
above).
.IP
.
.IP \fBtcp_src=\fIport\fR
.IQ \fBtcp_dst=\fIport\fR
.IQ \fBudp_src=\fIport\fR
.IQ \fBudp_dst=\fIport\fR
.IQ \fBsctp_src=\fIport\fR
.IQ \fBsctp_dst=\fIport\fR
Matches a TCP, UDP, or SCTP source or destination port \fIport\fR,
which is specified as a decimal number between 0 and 65535, inclusive.
.IP
When \fBdl_type\fR and \fBnw_proto\fR are wildcarded or set to values
that do not indicate an appropriate protocol, the values of these
settings are ignored (see \fBFlow Syntax\fR above).
.
.IP \fBtcp_src=\fIport\fB/\fImask\fR
.IQ \fBtcp_dst=\fIport\fB/\fImask\fR
.IQ \fBudp_src=\fIport\fB/\fImask\fR
.IQ \fBudp_dst=\fIport\fB/\fImask\fR
.IQ \fBsctp_src=\fIport\fB/\fImask\fR
.IQ \fBsctp_dst=\fIport\fB/\fImask\fR
Bitwise match on TCP (or UDP or SCTP) source or destination port.
The \fIport\fR and \fImask\fR are 16-bit numbers
written in decimal or in hexadecimal prefixed by \fB0x\fR.  Each 1-bit
in \fImask\fR requires that the corresponding bit in \fIport\fR must
match.  Each 0-bit in \fImask\fR causes the corresponding bit to be
ignored.
.IP
Bitwise matches on transport ports are rarely useful in isolation, but
a group of them can be used to reduce the number of flows required to
match on a range of transport ports.  For example, suppose that the
goal is to match TCP source ports 1000 to 1999, inclusive.  One way is
to insert 1000 flows, each of which matches on a single source port.
Another way is to look at the binary representations of 1000 and 1999,
as follows:
.br
.B "01111101000"
.br
.B "11111001111"
.br
and then to transform those into a series of bitwise matches that
accomplish the same results:
.br
.B "01111101xxx"
.br
.B "0111111xxxx"
.br
.B "10xxxxxxxxx"
.br
.B "110xxxxxxxx"
.br
.B "1110xxxxxxx"
.br
.B "11110xxxxxx"
.br
.B "1111100xxxx"
.br
which become the following when written in the syntax required by
\fBovs\-ofctl\fR:
.br
.B "tcp,tcp_src=0x03e8/0xfff8"
.br
.B "tcp,tcp_src=0x03f0/0xfff0"
.br
.B "tcp,tcp_src=0x0400/0xfe00"
.br
.B "tcp,tcp_src=0x0600/0xff00"
.br
.B "tcp,tcp_src=0x0700/0xff80"
.br
.B "tcp,tcp_src=0x0780/0xffc0"
.br
.B "tcp,tcp_src=0x07c0/0xfff0"
.IP
Only Open vSwitch 1.6 and later supports bitwise matching on transport
ports.
.IP
Like the exact-match forms described
above, the bitwise match forms apply only when \fBdl_type\fR and
\fBnw_proto\fR specify TCP or UDP or SCTP.
.
.IP \fBtp_src=\fIport\fR
.IQ \fBtp_dst=\fIport\fR
These are deprecated generic forms of L4 port matches.  In new code,
please use the TCP-, UDP-, or SCTP-specific forms described above.
.
.IP \fBtcp_flags=\fIflags\fB/\fImask\fR
.IQ \fBtcp_flags=\fR[\fB+\fIflag\fR...][\fB-\fIflag\fR...]
Bitwise match on TCP flags.  The \fIflags\fR and \fImask\fR are 16-bit
numbers written in decimal or in hexadecimal prefixed by \fB0x\fR.
Each 1-bit in \fImask\fR requires that the corresponding bit in
\fIflags\fR must match.  Each 0-bit in \fImask\fR causes the corresponding
bit to be ignored.
.IP
Alternatively, the flags can be specified by their symbolic names
(listed below), each preceded by either \fB+\fR for a flag that must
be set, or \fB\-\fR for a flag that must be unset, without any other
delimiters between the flags.  Flags not mentioned are wildcarded.
For example, \fBtcp,tcp_flags=+syn\-ack\fR matches TCP SYNs that are
not ACKs.
.IP
TCP protocol currently defines 9 flag bits, and additional 3 bits are
reserved (must be transmitted as zero), see RFCs 793, 3168, and 3540.
The flag bits are, numbering from the least significant bit:
.RS
.IP "\fB0: fin\fR"
No more data from sender.
.IP "\fB1: syn\fR"
Synchronize sequence numbers.
.IP "\fB2: rst\fR"
Reset the connection.
.IP "\fB3: psh\fR"
Push function.
.IP "\fB4: ack\fR"
Acknowledgement field significant.
.IP "\fB5: urg\fR"
Urgent pointer field significant.
.IP "\fB6: ece\fR"
ECN Echo.
.IP "\fB7: cwr\fR"
Congestion Windows Reduced.
.IP "\fB8: ns\fR"
Nonce Sum.
.IP "\fB9-11:\fR"
Reserved.
.IP "\fB12-15:\fR"
Not matchable, must be zero.
.RE
.IP \fBicmp_type=\fItype\fR
.IQ \fBicmp_code=\fIcode\fR
When \fBdl_type\fR and \fBnw_proto\fR specify ICMP or ICMPv6, \fItype\fR
matches the ICMP type and \fIcode\fR matches the ICMP code.  Each is
specified as a decimal number between 0 and 255, inclusive.
.IP
When \fBdl_type\fR and \fBnw_proto\fR take other values, the values of
these settings are ignored (see \fBFlow Syntax\fR above).
.
.IP \fBtable=\fInumber\fR
For flow dump commands, limits the flows dumped to those in the table
with the given \fInumber\fR between 0 and 254.  If not specified (or if
255 is specified as \fInumber\fR), then flows in all tables are
dumped.
.
.IP
For flow table modification commands, behavior varies based on the
OpenFlow version used to connect to the switch:
.
.RS
.IP "OpenFlow 1.0"
OpenFlow 1.0 does not support \fBtable\fR for modifying flows.
\fBovs\-ofctl\fR will exit with an error if \fBtable\fR (other than
\fBtable=255\fR) is specified for a switch that only supports OpenFlow
1.0.
.IP
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.
.IP
The OpenFlow 1.0 behavior in Open vSwitch for modifying or removing
flows depends on whether \fB\-\-strict\fR is used.  Without
\fB\-\-strict\fR, the command applies to matching flows in all tables.
With \fB\-\-strict\fR, 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.)
.
.IP "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.  \fBovs\-ofctl\fR
automatically enables the extension when \fBtable\fR is specified and
OpenFlow 1.0 is used.  \fBovs\-ofctl\fR automatically detects whether
the switch supports the extension.  As of this writing, this extension
is only known to be implemented by Open vSwitch.
.
.IP
With this extension, \fBovs\-ofctl\fR operates on the requested table
when \fBtable\fR is specified, and acts as described for OpenFlow 1.0
above when no \fBtable\fR is specified (or for \fBtable=255\fR).
.
.IP "OpenFlow 1.1"
OpenFlow 1.1 requires flow table modification commands to specify a
table.  When \fBtable\fR is not specified (or \fBtable=255\fR is
specified), \fBovs\-ofctl\fR defaults to table 0.
.
.IP "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.
.RE
.
.IP \fBmetadata=\fIvalue\fR[\fB/\fImask\fR]
Matches \fIvalue\fR either exactly or with optional \fImask\fR in the metadata
field. \fIvalue\fR and \fImask\fR are 64-bit integers, by default in decimal
(use a \fB0x\fR prefix to specify hexadecimal). Arbitrary \fImask\fR values
are allowed: a 1-bit in \fImask\fR indicates that the corresponding bit in
\fIvalue\fR must match exactly, and a 0-bit wildcards that bit. Matching on
metadata was added in Open vSwitch 1.8.
.
.PP
The following shorthand notations are also available:
.
.IP \fBip\fR
Same as \fBdl_type=0x0800\fR.
.
.IP \fBicmp\fR
Same as \fBdl_type=0x0800,nw_proto=1\fR.
.
.IP \fBtcp\fR
Same as \fBdl_type=0x0800,nw_proto=6\fR.
.
.IP \fBudp\fR
Same as \fBdl_type=0x0800,nw_proto=17\fR.
.
.IP \fBsctp\fR
Same as \fBdl_type=0x0800,nw_proto=132\fR.
.
.IP \fBarp\fR
Same as \fBdl_type=0x0806\fR.
.
.IP \fBrarp\fR
Same as \fBdl_type=0x8035\fR.
.
.PP
The following field assignments require support for the NXM (Nicira
Extended Match) extension to OpenFlow.  When one of these is specified,
\fBovs\-ofctl\fR will automatically attempt to negotiate use of this
extension.  If the switch does not support NXM, then \fBovs\-ofctl\fR
will report a fatal error.
.
.IP \fBvlan_tci=\fItci\fR[\fB/\fImask\fR]
Matches modified VLAN TCI \fItci\fR.  If \fImask\fR is omitted,
\fItci\fR is the exact VLAN TCI to match; if \fImask\fR is specified,
then a 1-bit in \fImask\fR indicates that the corresponding bit in
\fItci\fR must match exactly, and a 0-bit wildcards that bit.  Both
\fItci\fR and \fImask\fR are 16-bit values that are decimal by
default; use a \fB0x\fR prefix to specify them in hexadecimal.
.
.IP
The value that \fBvlan_tci\fR matches against is 0 for a packet that
has no 802.1Q header.  Otherwise, it is the TCI value from the 802.1Q
header with the CFI bit (with value \fB0x1000\fR) forced to 1.
.IP
Examples:
.RS
.IP \fBvlan_tci=0\fR
Match only packets without an 802.1Q header.
.IP \fBvlan_tci=0xf123\fR
Match packets tagged with priority 7 in VLAN 0x123.
.IP \fBvlan_tci=0x1123/0x1fff\fR
Match packets tagged with VLAN 0x123 (and any priority).
.IP \fBvlan_tci=0x5000/0xf000\fR
Match packets tagged with priority 2 (in any VLAN).
.IP \fBvlan_tci=0/0xfff\fR
Match packets with no 802.1Q header or tagged with VLAN 0 (and any
priority).
.IP \fBvlan_tci=0x5000/0xe000\fR
Match packets with no 802.1Q header or tagged with priority 2 (in any
VLAN).
.IP \fBvlan_tci=0/0xefff\fR
Match packets with no 802.1Q header or tagged with VLAN 0 and priority
0.
.RE
.IP
Some of these matching possibilities can also be achieved with
\fBdl_vlan\fR and \fBdl_vlan_pcp\fR.
.
.IP \fBip_frag=\fIfrag_type\fR
When \fBdl_type\fR specifies IP or IPv6, \fIfrag_type\fR
specifies what kind of IP fragments or non-fragments to match.  The
following values of \fIfrag_type\fR are supported:
.RS
.IP "\fBno\fR"
Matches only non-fragmented packets.
.IP "\fByes\fR"
Matches all fragments.
.IP "\fBfirst\fR"
Matches only fragments with offset 0.
.IP "\fBlater\fR"
Matches only fragments with nonzero offset.
.IP "\fBnot_later\fR"
Matches non-fragmented packets and fragments with zero offset.
.RE
.IP
The \fBip_frag\fR match type is likely to be most useful in
\fBnx\-match\fR mode.  See the description of the \fBset\-frags\fR
command, above, for more details.
.
.IP \fBarp_spa=\fIip\fR[\fB/\fInetmask\fR]
.IQ \fBarp_tpa=\fIip\fR[\fB/\fInetmask\fR]
When \fBdl_type\fR specifies either ARP or RARP, \fBarp_spa\fR and
\fBarp_tpa\fR match the source and target IPv4 address, respectively.
An address may be specified as an IP address or host name
(e.g. \fB192.168.1.1\fR or \fBwww.example.com\fR).  The optional
\fInetmask\fR allows restricting a match to an IPv4 address prefix.
The netmask may be specified as a dotted quad
(e.g. \fB192.168.1.0/255.255.255.0\fR) or as a CIDR block
(e.g. \fB192.168.1.0/24\fR).
.
.IP \fBarp_sha=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
.IQ \fBarp_tha=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
When \fBdl_type\fR specifies either ARP or RARP, \fBarp_sha\fR and
\fBarp_tha\fR match the source and target hardware address, respectively.  An
address is specified as 6 pairs of hexadecimal digits delimited by colons
(e.g. \fB00:0A:E4:25:6B:B0\fR).
.
.IP \fBarp_sha=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB/\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
.IQ \fBarp_tha=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB/\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
When \fBdl_type\fR specifies either ARP or RARP, \fBarp_sha\fR and
\fBarp_tha\fR match the source and target hardware address, respectively.  An
address is specified as 6 pairs of hexadecimal digits delimited by colons
(e.g. \fB00:0A:E4:25:6B:B0\fR), with a wildcard mask following the slash.
.

.IP \fBipv6_src=\fIipv6\fR[\fB/\fInetmask\fR]
.IQ \fBipv6_dst=\fIipv6\fR[\fB/\fInetmask\fR]
When \fBdl_type\fR is 0x86dd (possibly via shorthand, e.g., \fBipv6\fR
or \fBtcp6\fR), matches IPv6 source (or destination) address \fIipv6\fR,
which may be specified as defined in RFC 2373.  The preferred format is 
\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fB:\fIx\fR, where
\fIx\fR are the hexadecimal values of the eight 16-bit pieces of the
address.  A single instance of \fB::\fR may be used to indicate multiple
groups of 16-bits of zeros.  The optional \fInetmask\fR allows
restricting a match to an IPv6 address prefix.  A netmask is specified
as an IPv6 address (e.g. \fB2001:db8:3c4d:1::/ffff:ffff:ffff:ffff::\fR)
or a CIDR block (e.g. \fB2001:db8:3c4d:1::/64\fR).  Open vSwitch 1.8
and later support arbitrary masks; earlier versions support only CIDR
masks, that is, CIDR block and IPv6 addresses that are equivalent to
CIDR blocks.
.
.IP \fBipv6_label=\fIlabel\fR
When \fBdl_type\fR is 0x86dd (possibly via shorthand, e.g., \fBipv6\fR
or \fBtcp6\fR), matches IPv6 flow label \fIlabel\fR.
.
.IP \fBnd_target=\fIipv6\fR[\fB/\fInetmask\fR]
When \fBdl_type\fR, \fBnw_proto\fR, and \fBicmp_type\fR specify
IPv6 Neighbor Discovery (ICMPv6 type 135 or 136), matches the target address
\fIipv6\fR.  \fIipv6\fR is in the same format described earlier for the
\fBipv6_src\fR and \fBipv6_dst\fR fields.
.
.IP \fBnd_sll=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
When \fBdl_type\fR, \fBnw_proto\fR, and \fBicmp_type\fR specify IPv6
Neighbor Solicitation (ICMPv6 type 135), matches the source link\-layer
address option.  An address is specified as 6 pairs of hexadecimal
digits delimited by colons.
.
.IP \fBnd_tll=\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fB:\fIxx\fR
When \fBdl_type\fR, \fBnw_proto\fR, and \fBicmp_type\fR specify IPv6
Neighbor Advertisement (ICMPv6 type 136), matches the target link\-layer
address option.  An address is specified as 6 pairs of hexadecimal
digits delimited by colons.
.
.IP \fBmpls_bos=\fIbos\fR
When \fBdl_type\fR is 0x8847 or 0x8848 (possibly via shorthand e.g.,
\fBmpls\fR or \fBmplsm\fR), matches the bottom-of-stack bit of the
outer-most MPLS label stack entry. Valid values are 0 and 1.
.IP
If 1 then for a packet with a well-formed MPLS label stack the
bottom-of-stack bit indicates that the outer label stack entry is also
the inner-most label stack entry and thus that is that there is only one
label stack entry present.  Conversely, if 0 then for a packet with a
well-formed MPLS label stack the bottom-of-stack bit indicates that the
outer label stack entry is not the inner-most label stack entry and
thus there is more than one label stack entry present.
.
.IP \fBmpls_label=\fIlabel\fR
When \fBdl_type\fR is 0x8847 or 0x8848 (possibly via shorthand e.g.,
\fBmpls\fR or \fBmplsm\fR), matches the label of the outer
MPLS label stack entry. The label is a 20-bit value that is decimal by default;
use a \fB0x\fR prefix to specify them in hexadecimal.
.
.IP \fBmpls_tc=\fItc\fR
When \fBdl_type\fR is 0x8847 or 0x8848 (possibly via shorthand e.g.,
\fBmpls\fR or \fBmplsm\fR), matches the traffic-class of the outer
MPLS label stack entry. Valid values are between 0 (lowest) and 7 (highest).
.
.IP \fBtun_id=\fItunnel-id\fR[\fB/\fImask\fR]
.IQ \fBtunnel_id=\fItunnel-id\fR[\fB/\fImask\fR]
Matches tunnel identifier \fItunnel-id\fR.  Only packets that arrive
over a tunnel that carries a key (e.g. GRE with the RFC 2890 key
extension and a nonzero key value) will have a nonzero tunnel ID.
If \fImask\fR is omitted, \fItunnel-id\fR is the exact tunnel ID to match;
if \fImask\fR is specified, then a 1-bit in \fImask\fR indicates that the
corresponding bit in \fItunnel-id\fR must match exactly, and a 0-bit
wildcards that bit.
.
.IP \fBtun_src=\fIip\fR[\fB/\fInetmask\fR]
.IQ \fBtun_dst=\fIip\fR[\fB/\fInetmask\fR]
Matches tunnel IPv4 source (or destination) address \fIip\fR. Only packets
that arrive over a tunnel will have nonzero tunnel addresses.
The address may be specified as an IP address or host name
(e.g. \fB192.168.1.1\fR or \fBwww.example.com\fR).  The optional
\fInetmask\fR allows restricting a match to a masked IPv4 address.
The netmask may be specified as a dotted quad
(e.g. \fB192.168.1.0/255.255.255.0\fR) or as a CIDR block
(e.g. \fB192.168.1.0/24\fR).
.
.IP \fBtun_gbp_id=\fIvalue\fR[\fB/\fImask\fR]
.IQ \fBtun_gbp_flags=\fIvalue\fR[\fB/\fImask\fR]
Matches the group policy identifier and flags in the VXLAN header. Only
packets that arrive over a VXLAN tunnel with the "gbp" extension
enabled can have this field set. The fields may also be referred to by
NXM_NX_TUN_GBP_ID[] (16 bits) and NXM_NX_TUN_GBP_FLAGS[] (8 bits) in
the context of field manipulation actions. If these fields are set and
the packet matched by the flow is encapsulated in a VXLAN-GBP tunnel,
then the policy identifier and flags are transmitted to the destination
VXLAN tunnel endpoint.
.IP
The \fBtun_gbp_flags\fR field has the following format:
.IP
.in +2
\f(CR+-+-+-+-+-+-+-+-+\fR
.br
\f(CR|-|D|-|-|A|-|-|-|\fR
.br
\f(CR+-+-+-+-+-+-+-+-+\fR

.B D :=
Don't Learn bit. When set, this bit indicates that the egress
tunnel endpoint MUST NOT learn the source address of the encapsulated
frame.

.B A :=
Indicates that the group policy has already been applied to
this packet. Policies MUST NOT be applied by devices when the A bit is
set.
.in -2
.IP
For more information, please see the corresponding IETF draft:
https://tools.ietf.org/html/draft-smith-vxlan-group-policy
.
.IP "\fBtun_metadata\fIidx\fB=\fIvalue\fR[\fB/\fImask\fR]"
Matches \fIvalue\fR either exactly or with optional \fImask\fR in
tunnel metadata field number \fIidx\fR (numbered from 0 to 63).
Tunnel metadata fields can be dynamically assigned onto the data
contained in the options of Geneve packets using the commands
described in the section \fBOpenFlow Switch Geneve Option Table
Commands\fR. Once assigned, the length of the field is variable
according to the size of the option. Before updating a mapping in
the option table, flows with references to it should be removed,
otherwise the result is non-deterministic.
.IP
These fields were introduced in Open vSwitch 2.5.
.
.IP "\fBreg\fIidx\fB=\fIvalue\fR[\fB/\fImask\fR]"
Matches \fIvalue\fR either exactly or with optional \fImask\fR in
register number \fIidx\fR.  The valid range of \fIidx\fR depends on
the switch.  \fIvalue\fR and \fImask\fR are 32-bit integers, by
default in decimal (use a \fB0x\fR prefix to specify hexadecimal).
Arbitrary \fImask\fR values are allowed: a 1-bit in \fImask\fR
indicates that the corresponding bit in \fIvalue\fR must match
exactly, and a 0-bit wildcards that bit.
.IP
When a packet enters an OpenFlow switch, all of the registers are set
to 0.  Only explicit actions change register values.
.
.IP "\fBxreg\fIidx\fB=\fIvalue\fR[\fB/\fImask\fR]"
Matches \fIvalue\fR either exactly or with optional \fImask\fR in
64-bit ``extended register'' number \fIidx\fR.  Each of the 64-bit
extended registers overlays two of the 32-bit registers: \fBxreg0\fR
overlays \fBreg0\fR and \fBreg1\fR, with \fBreg0\fR supplying the
most-significant bits of \fBxreg0\fR and \fBreg1\fR the
least-significant.  \fBxreg1\fR similarly overlays \fBreg2\fR and
\fBreg3\fR, and so on.
.IP
These fields were added in Open vSwitch 2.3 to conform with the
OpenFlow 1.5 specification.  OpenFlow 1.5 calls these fields
just the ``packet registers,'' but Open vSwitch already had 32-bit
registers by that name, which is why Open vSwitch refers to the
standard registers as ``extended registers''.
.
.IP \fBpkt_mark=\fIvalue\fR[\fB/\fImask\fR]
Matches packet metadata mark \fIvalue\fR either exactly or with optional
\fImask\fR. The mark is associated data that may be passed into other
system components in order to facilitate interaction between subsystems.
On Linux this corresponds to the skb mark but the exact implementation is
platform-dependent.
.
.IP \fBactset_output=\fIport\fR
Matches the output port currently in the OpenFlow action set, where
\fIport\fR may be an OpenFlow port number or keyword
(e.g. \fBLOCAL\fR).  If there is no output port in the OpenFlow action
set, or if the output port will be ignored (e.g. because there is an
output group in the OpenFlow action set), then the value will be
\fBUNSET\fR.
.IP
This field was introduced in Open vSwitch 2.4 to conform with the
OpenFlow 1.5 specification.
.
.IP \fBconj_id=\fIvalue\fR
Matches the given 32-bit \fIvalue\fR against the conjunction ID.  This
is used only with the \fBconjunction\fR action (see below).
.IP
This field was introduced in Open vSwitch 2.4.
.
.PP
Defining IPv6 flows (those with \fBdl_type\fR equal to 0x86dd) requires
support for NXM.  The following shorthand notations are available for
IPv6-related flows:
.
.IP \fBipv6\fR
Same as \fBdl_type=0x86dd\fR.
.
.IP \fBtcp6\fR
Same as \fBdl_type=0x86dd,nw_proto=6\fR.
.
.IP \fBudp6\fR
Same as \fBdl_type=0x86dd,nw_proto=17\fR.
.
.IP \fBsctp6\fR
Same as \fBdl_type=0x86dd,nw_proto=132\fR.
.
.IP \fBicmp6\fR
Same as \fBdl_type=0x86dd,nw_proto=58\fR.
.
.PP
Finally, field assignments to \fBduration\fR, \fBn_packets\fR, or
\fBn_bytes\fR are ignored to allow output from the \fBdump\-flows\fR
command to be used as input for other commands that parse flows.
.
.PP
The \fBadd\-flow\fR, \fBadd\-flows\fR, and \fBmod\-flows\fR commands
require an additional field, which must be the final field specified:
.
.IP \fBactions=\fR[\fIaction\fR][\fB,\fIaction\fR...]\fR
Specifies a comma-separated list of actions to take on a packet when the 
flow entry matches.  If no \fIaction\fR is specified, then packets
matching the flow are dropped.  The following forms of \fIaction\fR
are supported:
.
.RS
.IP \fIport\fR
.IQ \fBoutput:\fIport\fR
Outputs the packet to OpenFlow port number \fIport\fR.  If \fIport\fR
is the packet's input port, the packet is not output.
.
.IP \fBoutput:\fIsrc\fB[\fIstart\fB..\fIend\fB]
Outputs the packet to the OpenFlow port number read from \fIsrc\fR,
which must be an NXM field as described above.  For example,
\fBoutput:NXM_NX_REG0[16..31]\fR 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.
.IP
This form of \fBoutput\fR was added in Open vSwitch 1.3.0.  This form
of \fBoutput\fR uses an OpenFlow extension that is not supported by
standard OpenFlow switches.
.
.IP \fBgroup:\fIgroup_id\fR
Outputs the packet to the OpenFlow group \fIgroup_id\fR. Group tables
are only supported in OpenFlow 1.1+. See Group Syntax for more details.
.
.IP \fBnormal\fR
Subjects the packet to the device's normal L2/L3 processing.  (This
action is not implemented by all OpenFlow switches.)
.
.IP \fBflood\fR
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).
.
.IP \fBall\fR
Outputs the packet on all switch physical ports other than the port on
which it was received.
.
.IP \fBlocal\fR
Outputs the packet on the ``local port,'' which corresponds to the
network device that has the same name as the bridge.
.
.IP \fBin_port\fR
Outputs the packet on the port from which it was received.
.
.IP \fBcontroller(\fIkey\fB=\fIvalue\fR...\fB)
Sends the packet to the OpenFlow controller as a ``packet in''
message.  The supported key-value pairs are:
.RS
.IP "\fBmax_len=\fInbytes\fR"
Limit to \fInbytes\fR the number of bytes of the packet to send to
the controller.  By default the entire packet is sent.
.IP "\fBreason=\fIreason\fR"
Specify \fIreason\fR as the reason for sending the message in the
``packet in'' message.  The supported reasons are \fBaction\fR (the
default), \fBno_match\fR, and \fBinvalid_ttl\fR.
.IP "\fBid=\fIcontroller-id\fR"
Specify \fIcontroller-id\fR, 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 \fBNXT_SET_CONTROLLER_ID\fR Nicira extension to
OpenFlow.
.RE
.IP
Any \fIreason\fR other than \fBaction\fR and any nonzero
\fIcontroller-id\fR uses a Nicira vendor extension that, as of this
writing, is only known to be implemented by Open vSwitch (version 1.6
or later).
.
.IP \fBcontroller\fR
.IQ \fBcontroller\fR[\fB:\fInbytes\fR]
Shorthand for \fBcontroller()\fR or
\fBcontroller(max_len=\fInbytes\fB)\fR, respectively.
.
.IP \fBenqueue(\fIport\fB,\fIqueue\fB)\fR
Enqueues the packet on the specified \fIqueue\fR within port
\fIport\fR, which must be an OpenFlow port number or keyword
(e.g. \fBLOCAL\fR).  The number of supported queues depends on the
switch; some OpenFlow implementations do not support queuing at all.
.
.IP \fBdrop\fR
Discards the packet, so no further processing or forwarding takes place.
If a drop action is used, no other actions may be specified.
.
.IP \fBmod_vlan_vid\fR:\fIvlan_vid\fR
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 \fBmod_vlan_pcp\fR action to set
this).
.
.IP \fBmod_vlan_pcp\fR:\fIvlan_pcp\fR
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 \fBmod_vlan_vid\fR action to set this).
.
.IP \fBstrip_vlan\fR
Strips the VLAN tag from a packet if it is present.
.
.IP \fBpush_vlan\fR:\fIethertype\fR
Push a new VLAN tag onto the packet.  Ethertype is used as the 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.
.
.IP \fBpush_mpls\fR:\fIethertype\fR
Changes the packet's Ethertype to \fIethertype\fR, which must be either
\fB0x8847\fR or \fB0x8848\fR, and pushes an MPLS LSE.
.IP
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).
.IP
If the packet does already contain an MPLS label, pushes a new
outermost label as a copy of the existing outermost label.
.IP
A limitation of the implementation is that processing of actions will stop
if \fBpush_mpls\fR follows another \fBpush_mpls\fR unless there is a
\fBpop_mpls\fR in between.
.
.IP \fBpop_mpls\fR:\fIethertype\fR
Strips the outermost MPLS label stack entry.
Currently the implementation restricts \fIethertype\fR to a non-MPLS Ethertype
and thus \fBpop_mpls\fR 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 \fBpop_mpls\fR follows another \fBpop_mpls\fR unless
there is a \fBpush_mpls\fR in between.
.
.IP \fBmod_dl_src\fB:\fImac\fR
Sets the source Ethernet address to \fImac\fR.
.
.IP \fBmod_dl_dst\fB:\fImac\fR
Sets the destination Ethernet address to \fImac\fR.
.
.IP \fBmod_nw_src\fB:\fIip\fR
Sets the IPv4 source address to \fIip\fR.
.
.IP \fBmod_nw_dst\fB:\fIip\fR
Sets the IPv4 destination address to \fIip\fR.
.
.IP \fBmod_tp_src\fB:\fIport\fR
Sets the TCP or UDP or SCTP source port to \fIport\fR.
.
.IP \fBmod_tp_dst\fB:\fIport\fR
Sets the TCP or UDP or SCTP destination port to \fIport\fR.
.
.IP \fBmod_nw_tos\fB:\fItos\fR
Sets the DSCP bits in the IPv4 ToS/DSCP or IPv6 traffic class field to
\fItos\fR, 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).
.
.IP \fBmod_nw_ecn\fB:\fIecn\fR
Sets the ECN bits in the IPv4 ToS or IPv6 traffic class field to \fIecn\fR,
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).
.IP
Requires OpenFlow 1.1 or later.
.
.IP \fBmod_nw_ttl\fB:\fIttl\fR
Sets the IPv4 TTL or IPv6 hop limit field to \fIttl\fR, which is specified as
a decimal number between 0 and 255, inclusive.  Switch behavior when setting
\fIttl\fR to zero is not well specified, though.
.IP
Requires OpenFlow 1.1 or later.
.RE
.IP
The following actions are Nicira vendor extensions that, as of this writing, are
only known to be implemented by Open vSwitch:
.
.RS
.
.IP \fBresubmit\fB:\fIport\fR
.IQ \fBresubmit\fB(\fR[\fIport\fR]\fB,\fR[\fItable\fR]\fB)
Re-searches this OpenFlow flow table (or the table whose number is
specified by \fItable\fR) with the \fBin_port\fR field replaced by
\fIport\fR (if \fIport\fR is specified) and executes the actions
found, if any, in addition to any other actions in this flow entry.
.IP
Recursive \fBresubmit\fR actions are obeyed up to an
implementation-defined maximum depth.  Open vSwitch 1.0.1 and earlier
did not support recursion; Open vSwitch before 1.2.90 did not support
\fItable\fR.
.
.IP \fBset_tunnel\fB:\fIid\fR
.IQ \fBset_tunnel64\fB:\fIid\fR
If outputting to a port that encapsulates the packet in a tunnel and
supports an identifier (such as GRE), sets the identifier to \fIid\fR.
If the \fBset_tunnel\fR form is used and \fIid\fR fits in 32 bits,
then this uses an action extension that is supported by Open vSwitch
1.0 and later.  Otherwise, if \fIid\fR is a 64-bit value, it requires
Open vSwitch 1.1 or later.
.
.IP \fBset_queue\fB:\fIqueue\fR
Sets the queue that should be used to \fIqueue\fR when packets are
output.  The number of supported queues depends on the switch; some
OpenFlow implementations do not support queuing at all.
.
.IP \fBpop_queue\fR
Restores the queue to the value it was before any \fBset_queue\fR
actions were applied.
.
.IP \fBdec_ttl\fR
.IQ \fBdec_ttl\fB[\fR(\fIid1,id2\fI)\fR]\fR
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 \fBOFPR_INVALID_TTL\fR 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 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.
.
.IP \fBset_mpls_label\fR:\fIlabel\fR
Set the label of the outer MPLS label stack entry of a packet.
\fIlabel\fR should be a 20-bit value that is decimal by default;
use a \fB0x\fR prefix to specify them in hexadecimal.
.
.IP \fBset_mpls_tc\fR:\fItc\fR
Set the traffic-class of the outer MPLS label stack entry of a packet.
\fItc\fR should be a in the range 0 to 7 inclusive.
.
.IP \fBset_mpls_ttl\fR:\fIttl\fR
Set the TTL of the outer MPLS label stack entry of a packet.
\fIttl\fR should be in the range 0 to 255 inclusive.
.
.IP \fBdec_mpls_ttl\fR
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 \fBOFPR_INVALID_TTL\fR
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.
.
.IP \fBnote:\fR[\fIhh\fR]...
Does nothing at all.  Any number of bytes represented as hex digits
\fIhh\fR may be included.  Pairs of hex digits may be separated by
periods for readability.
The \fBnote\fR 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.
.
.IP "\fBmove:\fIsrc\fB[\fIstart\fB..\fIend\fB]\->\fIdst\fB[\fIstart\fB..\fIend\fB]\fR"
Copies the named bits from field \fIsrc\fR to field \fIdst\fR.
\fIsrc\fR and \fIdst\fR must be NXM field names as defined in
\fBnicira\-ext.h\fR, e.g. \fBNXM_OF_UDP_SRC\fR or \fBNXM_NX_REG0\fR.
Each \fIstart\fR and \fIend\fR pair, which are inclusive, must specify
the same number of bits and must fit within its respective field.
Shorthands for \fB[\fIstart\fB..\fIend\fB]\fR exist: use
\fB[\fIbit\fB]\fR to specify a single bit or \fB[]\fR to specify an
entire field.
.IP
Examples: \fBmove:NXM_NX_REG0[0..5]\->NXM_NX_REG1[26..31]\fR copies the
six bits numbered 0 through 5, inclusive, in register 0 into bits 26
through 31, inclusive;
\fBmove:NXM_NX_REG0[0..15]\->NXM_OF_VLAN_TCI[]\fR copies the least
significant 16 bits of register 0 into the VLAN TCI field.
.IP
In OpenFlow 1.0 through 1.4, \fBmove\fR ordinarily uses an Open
vSwitch extension to OpenFlow.  In OpenFlow 1.5, \fBmove\fR uses the
OpenFlow 1.5 standard \fBcopy_field\fR action.  The ONF has
also made \fBcopy_field\fR 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, \fBovs\-ofctl\fR does not use it.
.
.IP "\fBset_field:\fIvalue\fR[/\fImask\fR]\fB\->\fIdst"
.IQ "\fBload:\fIvalue\fB\->\fIdst\fB[\fIstart\fB..\fIend\fB]"
Loads a literal value into a field or part of a field.  With
\fBset_field\fR, \fBvalue\fR and the optional \fBmask\fR are given in
the customary syntax for field \fIdst\fR, which is expressed as a
field name.  For example, \fBset_field:00:11:22:33:44:55->eth_src\fR
sets the Ethernet source address to 00:11:22:33:44:55.  With
\fBload\fR, \fIvalue\fR must be an integer value (in decimal or
prefixed by \fB0x\fR for hexadecimal) and \fIdst\fR is the NXM or OXM
name for the field.  For example,
\fBload:0x001122334455->OXM_OF_ETH_DST[]\fR has the same effect as the
prior \fBset_field\fR example.
.IP
The two forms exist for historical reasons.  Open vSwitch 1.1
introduced \fBNXAST_REG_LOAD\fR as a Nicira extension to OpenFlow 1.0
and used \fBload\fR to express it.  Later, OpenFlow 1.2 introduced a
standard \fBOFPAT_SET_FIELD\fR action that was restricted to loading
entire fields, so Open vSwitch added the form \fBset_field\fR with
this restriction.  OpenFlow 1.5 extended \fBOFPAT_SET_FIELD\fR to the
point that it became a superset of \fBNXAST_REG_LOAD\fR.  Open vSwitch
translates either syntax as necessary for the OpenFlow version in use:
in OpenFlow 1.0 and 1.1, \fBNXAST_REG_LOAD\fR; in OpenFlow 1.2, 1.3,
and 1.4, \fBNXAST_REG_LOAD\fR for \fBload\fR or for loading a
subfield, \fBOFPAT_SET_FIELD\fR otherwise; and OpenFlow 1.5 and later,
\fBOFPAT_SET_FIELD\fR.
.
.IP "\fBpush:\fIsrc\fB[\fIstart\fB..\fIend\fB]"
Pushes \fIstart\fR to \fIend\fR bits inclusive, in fields
on top of the stack.
.IP
Example: \fBpush:NXM_NX_REG2[0..5]\fR push the value stored in register
2 bits 0 through 5, inclusive, on to the internal stack.
.
.IP "\fBpop:\fIdst\fB[\fIstart\fB..\fIend\fB]"
Pops from the top of the stack, retrieves the \fIstart\fR to \fIend\fR bits
inclusive, from the value popped and store them into the corresponding
bits in \fIdst\fR.
.
.IP
Example: \fBpop:NXM_NX_REG2[0..5]\fR 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.
.
.
.IP "\fBmultipath(\fIfields\fB, \fIbasis\fB, \fIalgorithm\fB, \fIn_links\fB, \fIarg\fB, \fIdst\fB[\fIstart\fB..\fIend\fB])\fR"
Hashes \fIfields\fR using \fIbasis\fR as a universal hash parameter,
then the applies multipath link selection \fIalgorithm\fR (with
parameter \fIarg\fR) to choose one of \fIn_links\fR output links
numbered 0 through \fIn_links\fR minus 1, and stores the link into
\fIdst\fB[\fIstart\fB..\fIend\fB]\fR, which must be an NXM field as
described above.
.IP
Currently, \fIfields\fR must be either \fBeth_src\fR or
\fBsymmetric_l4\fR and \fIalgorithm\fR must be one of \fBmodulo_n\fR,
\fBhash_threshold\fR, \fBhrw\fR, and \fBiter_hash\fR.  Only
the \fBiter_hash\fR algorithm uses \fIarg\fR.
.IP
Refer to \fBnicira\-ext.h\fR for more details.
.
.IP "\fBbundle(\fIfields\fB, \fIbasis\fB, \fIalgorithm\fB, \fIslave_type\fB, slaves:[\fIs1\fB, \fIs2\fB, ...])\fR"
Hashes \fIfields\fR using \fIbasis\fR as a universal hash parameter, then
applies the bundle link selection \fIalgorithm\fR to choose one of the listed
slaves represented as \fIslave_type\fR.  Currently the only supported
\fIslave_type\fR is \fBofport\fR.  Thus, each \fIs1\fR through \fIsN\fR should
be an OpenFlow port number. Outputs to the selected slave.
.IP
Currently, \fIfields\fR must be either \fBeth_src\fR or \fBsymmetric_l4\fR and
\fIalgorithm\fR must be one of \fBhrw\fR and \fBactive_backup\fR.
.IP
Example: \fBbundle(eth_src,0,hrw,ofport,slaves:4,8)\fR uses an Ethernet source
hash with basis 0, to select between OpenFlow ports 4 and 8 using the Highest
Random Weight algorithm.
.IP
Refer to \fBnicira\-ext.h\fR for more details.
.
.IP "\fBbundle_load(\fIfields\fB, \fIbasis\fB, \fIalgorithm\fB, \fIslave_type\fB, \fIdst\fB[\fIstart\fB..\fIend\fB], slaves:[\fIs1\fB, \fIs2\fB, ...])\fR"
Has the same behavior as the \fBbundle\fR action, with one exception.  Instead
of outputting to the selected slave, it writes its selection to
\fIdst\fB[\fIstart\fB..\fIend\fB]\fR, which must be an NXM field as described
above.
.IP
Example: \fBbundle_load(eth_src, 0, hrw, ofport, NXM_NX_REG0[],
slaves:4, 8)\fR 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 \fBNXM_NX_REG0[]\fR.
.IP
Refer to \fBnicira\-ext.h\fR for more details.
.
.IP "\fBlearn(\fIargument\fR[\fB,\fIargument\fR]...\fB)\fR"
This action adds or modifies a flow in an OpenFlow table, similar to
\fBovs\-ofctl \-\-strict mod\-flows\fR.  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.
.RS
.IP \fBidle_timeout=\fIseconds\fR
.IQ \fBhard_timeout=\fIseconds\fR
.IQ \fBpriority=\fIvalue\fR
.IQ \fBcookie=\fIvalue\fR
.IQ \fBsend_flow_rem\fR
These arguments have the same meaning as in the usual \fBovs\-ofctl\fR
flow syntax.
.
.IP \fBfin_idle_timeout=\fIseconds\fR
.IQ \fBfin_hard_timeout=\fIseconds\fR
Adds a \fBfin_timeout\fR action with the specified arguments to the
new flow.  This feature was added in Open vSwitch 1.5.90.
.
.IP \fBtable=\fInumber\fR
The table in which the new flow should be inserted.  Specify a decimal
number between 0 and 254.  The default, if \fBtable\fR is unspecified,
is table 1.
.
.IP \fBdelete_learned\fR
This flag enables deletion of the learned flows when the flow with the
\fBlearn\fR action is removed.  Specifically, when the last
\fBlearn\fR action with this flag and particular \fBtable\fR and
\fBcookie\fR values is removed, the switch deletes all of the flows in
the specified table with the specified cookie.
.
.IP
This flag was added in Open vSwitch 2.4.
.
.IP \fIfield\fB=\fIvalue\fR
.IQ \fIfield\fB[\fIstart\fB..\fIend\fB]=\fIsrc\fB[\fIstart\fB..\fIend\fB]\fR
.IQ \fIfield\fB[\fIstart\fB..\fIend\fB]\fR
Adds a match criterion to the new flow.
.IP
The first form specifies that \fIfield\fR must match the literal
\fIvalue\fR, e.g. \fBdl_type=0x0800\fR.  All of the fields and values
for \fBovs\-ofctl\fR flow syntax are available with their usual
meanings.
.IP
The second form specifies that \fIfield\fB[\fIstart\fB..\fIend\fB]\fR
in the new flow must match \fIsrc\fB[\fIstart\fB..\fIend\fB]\fR taken
from the flow currently being processed.
.IP
The third form is a shorthand for the second form.  It specifies that
\fIfield\fB[\fIstart\fB..\fIend\fB]\fR in the new flow must match
\fIfield\fB[\fIstart\fB..\fIend\fB]\fR taken from the flow currently
being processed.
.
.IP \fBload:\fIvalue\fB\->\fIdst\fB[\fIstart\fB..\fIend\fB]
.IQ \fBload:\fIsrc\fB[\fIstart\fB..\fIend\fB]\->\fIdst\fB[\fIstart\fB..\fIend\fB]
.
Adds a \fBload\fR action to the new flow.
.IP
The first form loads the literal \fIvalue\fR into bits \fIstart\fR
through \fIend\fR, inclusive, in field \fIdst\fR.  Its syntax is the
same as the \fBload\fR action described earlier in this section.
.IP
The second form loads \fIsrc\fB[\fIstart\fB..\fIend\fB]\fR, a value
from the flow currently being processed, into bits \fIstart\fR
through \fIend\fR, inclusive, in field \fIdst\fR.
.
.IP \fBoutput:\fIfield\fB[\fIstart\fB..\fIend\fB]\fR
Add an \fBoutput\fR action to the new flow's actions, that outputs to
the OpenFlow port taken from \fIfield\fB[\fIstart\fB..\fIend\fB]\fR,
which must be an NXM field as described above.
.RE
.IP
For best performance, segregate learned flows into a table (using
\fBtable=\fInumber\fR) 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 \fBtable\fR is 1, to
keep the learned flows separate from the primary flow table 0.)
.RE
.
.RS
.
.IP \fBclear_actions\fR
Clears all the actions in the action set immediately.
.
.IP \fBwrite_actions(\fR[\fIaction\fR][\fB,\fIaction\fR...]\fB)
Add the specific actions to the action set.  The syntax of
\fIactions\fR is the same as in the \fBactions=\fR field.  The action
set is carried between flow tables and then executed at the end of the
pipeline.
.
.IP
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:
.
.RS
.IP 1.
\fBstrip_vlan\fR
.IQ
\fBpop_mpls\fR
.
.IP 2.
\fBpush_mpls\fR
.
.IP 3.
\fBpush_vlan\fR
.
.IP 4.
\fBdec_ttl\fR
.IQ
\fBdec_mpls_ttl\fR
.
.IP 5.
\fBload\fR
.IQ
\fBmove\fR
.IQ
\fBmod_dl_dst\fR
.IQ
\fBmod_dl_src\fR
.IQ
\fBmod_nw_dst\fR
.IQ
\fBmod_nw_src\fR
.IQ
\fBmod_nw_tos\fR
.IQ
\fBmod_nw_ecn\fR
.IQ
\fBmod_nw_ttl\fR
.IQ
\fBmod_tp_dst\fR
.IQ
\fBmod_tp_src\fR
.IQ
\fBmod_vlan_pcp\fR
.IQ
\fBmod_vlan_vid\fR
.IQ
\fBset_field\fR
.IQ
\fBset_tunnel\fR
.IQ
\fBset_tunnel64\fR
.IQ
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.
.
.IP 6.
\fBset_queue\fR
.
.IP 7.
\fBgroup\fR
.IQ
\fBoutput\fR
.IQ
\fBresubmit\fR
.IQ
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.)
.RE
.IP
Only the actions listed above may be written to the action set.
.
.IP \fBwrite_metadata\fB:\fIvalue\fR[/\fImask\fR]
Updates the metadata field for the flow. If \fImask\fR is omitted, the
metadata field is set exactly to \fIvalue\fR; if \fImask\fR is specified, then
a 1-bit in \fImask\fR indicates that the corresponding bit in the metadata
field will be replaced with the corresponding bit from \fIvalue\fR. Both
\fIvalue\fR and \fImask\fR are 64-bit values that are decimal by default; use
a \fB0x\fR prefix to specify them in hexadecimal.
.
.IP \fBmeter\fR:\fImeter_id\fR
Apply the \fImeter_id\fR 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 \fBMeter Table Commands\fR, above,
for more details.
.
.IP \fBgoto_table\fR:\fItable\fR
Indicates the next table in the process pipeline.
.
.IP "\fBfin_timeout(\fIargument\fR[\fB,\fIargument\fR]\fB)"
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.
.IP
\fIargument\fR takes the following forms:
.RS
.IP "\fBidle_timeout=\fIseconds\fR"
Causes the flow to expire after the given number of seconds of
inactivity.
.
.IP "\fBhard_timeout=\fIseconds\fR"
Causes the flow to expire after the given number of seconds,
regardless of activity.  (\fIseconds\fR specifies time since the
flow's creation, not since the receipt of the FIN or RST.)
.RE
.IP
This action was added in Open vSwitch 1.5.90.
.
.IP "\fBsample(\fIargument\fR[\fB,\fIargument\fR]...\fB)\fR"
Samples packets and sends one sample for every sampled packet.
.IP
\fIargument\fR takes the following forms:
.RS
.IP "\fBprobability=\fIpackets\fR"
The number of sampled packets out of 65535.  Must be greater or equal to 1.
.IP "\fBcollector_set_id=\fIid\fR"
The unsigned 32-bit integer identifier of the set of sample collectors
to send sampled packets to.  Defaults to 0.
.IP "\fBobs_domain_id=\fIid\fR"
When sending samples to IPFIX collectors, the unsigned 32-bit integer
Observation Domain ID sent in every IPFIX flow record.  Defaults to 0.
.IP "\fBobs_point_id=\fIid\fR"
When sending samples to IPFIX collectors, the unsigned 32-bit integer
Observation Point ID sent in every IPFIX flow record.  Defaults to 0.
.RE
.IP
Refer to \fBovs\-vswitchd.conf.db\fR(8) for more details on
configuring sample collector sets.
.IP
This action was added in Open vSwitch 1.10.90.
.
.IP "\fBexit\fR"
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 \fBresubmit\fR call stack,
are ignored.  Actions in the action set is still executed (specify
\fBclear_actions\fR before \fBexit\fR to discard them).
.
.IP "\fBconjunction(\fIid\fB, \fIk\fB/\fIn\fR\fB)\fR"
An individual OpenFlow flow can match only a single value for each
field.  However, situations often arise where one wants to match one
of a set of values within a field or fields.  For matching a single
field against a set, it is straightforward and efficient to add
multiple flows to the flow table, one for each value in the set.  For
example, one might use the following flows to send packets with IP
source address \fIa\fR, \fIb\fR, \fIc\fR, or \fId\fR to the OpenFlow
controller:
.RS +1in
.br
\fBip,ip_src=\fIa\fB actions=controller\fR
.br
\fBip,ip_src=\fIb\fB actions=controller\fR
.br
\fBip,ip_src=\fIc\fB actions=controller\fR
.br
\fBip,ip_src=\fId\fB actions=controller\fR
.br
.RE
.IP
Similarly, these flows send packets with IP destination address
\fIe\fR, \fIf\fR, \fIg\fR, or \fIh\fR to the OpenFlow controller:
.RS +1in
.br
\fBip,ip_dst=\fIe\fB actions=controller\fR
.br
\fBip,ip_dst=\fIf\fB actions=controller\fR
.br
\fBip,ip_dst=\fIg\fB actions=controller\fR
.br
\fBip,ip_dst=\fIh\fB actions=controller\fR
.br
.RE
.IP
Installing all of the above flows in a single flow table yields a
disjunctive effect: a packet is sent to the controller if \fBip_src\fR
\[mo] {\fIa\fR,\fIb\fR,\fIc\fR,\fId\fR} or \fBip_dst\fR \[mo]
{\fIe\fR,\fIf\fR,\fIg\fR,\fIh\fR} (or both).  (Pedantically, if both
of the above sets of flows are present in the flow table, they should
have different priorities, because OpenFlow says that the results are
undefined when two flows with same priority can both match a single
packet.)
.IP
Suppose, on the other hand, one wishes to match conjunctively, that
is, to send a packet to the controller only if both \fBip_src\fR \[mo]
{\fIa\fR,\fIb\fR,\fIc\fR,\fId\fR} and \fBip_dst\fR \[mo]
{\fIe\fR,\fIf\fR,\fIg\fR,\fIh\fR}.  This requires 4 \[mu] 4 = 16
flows, one for each possible pairing of \fBip_src\fR and \fBip_dst\fR.
That is acceptable for our small example, but it does not gracefully
extend to larger sets or greater numbers of dimensions.
.IP
The \fBconjunction\fR action is a solution for conjunctive matches
that is built into Open vSwitch.  A \fBconjunction\fR action ties
groups of individual OpenFlow flows into higher-level ``conjunctive
flows''.  Each group corresponds to one dimension, and each flow
within the group matches one possible value for the dimension.  A
packet that matches one flow from each group matches the conjunctive
flow.
.IP
To implement a conjunctive flow with \fBconjunction\fR, assign the
conjunctive flow a 32-bit \fIid\fR, which must be unique within an
OpenFlow table.  Assign each of the \fIn\fR \[>=] 2 dimensions a
unique number from 1 to \fIn\fR; the ordering is unimportant.  Add one
flow to the OpenFlow flow table for each possible value of each
dimension with \fBconjunction(\fIid, \fIk\fB/\fIn\fB)\fR as the flow's
actions, where \fIk\fR is the number assigned to the flow's dimension.
Together, these flows specify the conjunctive flow's match condition.
When the conjunctive match condition is met, Open vSwitch looks up one
more flow that specifies the conjunctive flow's actions and receives
its statistics.  This flow is found by setting \fBconj_id\fR to the
specified \fIid\fR and then again searching the flow table.
.IP
The following flows provide an example.  Whenever the IP source is one
of the values in the flows that match on the IP source (dimension 1 of
2), \fIand\fR the IP destination is one of the values in the flows
that match on IP destination (dimension 2 of 2), Open vSwitch searches
for a flow that matches \fBconj_id\fR against the conjunction ID
(1234), finding the first flow listed below.
.RS +1in
.br
.B "conj_id=1234 actions=controller"
.br
.B "ip,ip_src=10.0.0.1 actions=conjunction(1234, 1/2)"
.br
.B "ip,ip_src=10.0.0.4 actions=conjunction(1234, 1/2)"
.br
.B "ip,ip_src=10.0.0.6 actions=conjunction(1234, 1/2)"
.br
.B "ip,ip_src=10.0.0.7 actions=conjunction(1234, 1/2)"
.br
.B "ip,ip_dst=10.0.0.2 actions=conjunction(1234, 2/2)"
.br
.B "ip,ip_dst=10.0.0.5 actions=conjunction(1234, 2/2)"
.br
.B "ip,ip_dst=10.0.0.7 actions=conjunction(1234, 2/2)"
.br
.B "ip,ip_dst=10.0.0.8 actions=conjunction(1234, 2/2)"
.RE
.IP
Many subtleties exist:
.RS
.IP \(bu
In the example above, every flow in a single dimension has the same
form, that is, dimension 1 matches on \fBip_src\fR, dimension 2 on
\fBip_dst\fR, but this is not a requirement.  Different flows within a
dimension may match on different bits within a field (e.g. IP network
prefixes of different lengths, or TCP/UDP port ranges as bitwise
matches), or even on entirely different fields (e.g. to match packets
for TCP source port 80 or TCP destination port 80).
.IP \(bu
The flows within a dimension can vary their matches across more than
one field, e.g. to match only specific pairs of IP source and
destination addresses or L4 port numbers.
.IP \(bu
A flow may have multiple \fBconjunction\fR actions, with different
\fIid\fR values.  This is useful for multiple conjunctive flows with
overlapping sets.  If one conjunctive flow matches packets with both
\fBip_src\fR \[mo] {\fIa\fR,\fIb\fR} and \fBip_dst\fR \[mo]
{\fId\fR,\fIe\fR} and a second conjunctive flow matches \fBip_src\fR
\[mo] {\fIb\fR,\fIc\fR} and \fBip_dst\fR \[mo] {\fIf\fR,\fIg\fR}, for
example, then the flow that matches \fBip_src=\fIb\fR would have two
\fBconjunction\fR actions, one for each conjunctive flow.  The order
of \fBconjunction\fR actions within a list of actions is not
significant.
.IP \(bu
A flow with \fBconjunction\fR actions may also include \fBnote\fR
actions for annotations, but not any other kind of actions.  (They
would not be useful because they would never be executed.)
.IP \(bu
All of the flows that constitute a conjunctive flow with a given
\fIid\fR must have the same priority.  (Flows with the same \fIid\fR
but different priorities are currently treated as different
conjunctive flows, that is, currently \fIid\fR values need only be
unique within an OpenFlow table at a given priority.  This behavior
isn't guaranteed to stay the same in later releases, so please use
\fIid\fR values unique within an OpenFlow table.)
.IP \(bu
Conjunctive flows must not overlap with each other, at a given
priority, that is, any given packet must be able to match at most one
conjunctive flow at a given priority.  Overlapping conjunctive flows
yield unpredictable results.
.IP \(bu
Following a conjunctive flow match, the search for the flow with
\fBconj_id=\fIid\fR is done in the same general-purpose way as other flow
table searches, so one can use flows with \fBconj_id=\fIid\fR to act
differently depending on circumstances.  (One exception is that the
search for the \fBconj_id=\fIid\fR flow itself ignores conjunctive flows,
to avoid recursion.) If the search with \fBconj_id=\fIid\fR fails, Open
vSwitch acts as if the conjunctive flow had not matched at all, and
continues searching the flow table for other matching flows.
.IP \(bu
OpenFlow prerequisite checking occurs for the flow with
\fBconj_id=\fIid\fR in the same way as any other flow, e.g. in an
OpenFlow 1.1+ context, putting a \fBmod_nw_src\fR action into the
example above would require adding an \fBip\fR match, like this:
.RS +1in
.br
.B "conj_id=1234,ip actions=mod_nw_src:1.2.3.4,controller"
.br
.RE
.IP \(bu
OpenFlow prerequisite checking also occurs for the individual flows
that comprise a conjunctive match in the same way as any other flow.
.IP \(bu
The flows that constitute a conjunctive flow do not have useful
statistics.  They are never updated with byte or packet counts, and so
on.  (For such a flow, therefore, the idle and hard timeouts work much
the same way.)
.IP \(bu
Conjunctive flows can be a useful building block for negation, that
is, inequality matches like \fBtcp_src\fR \[!=] 80.  To implement an
inequality match, convert it to a pair of range matches, e.g. 0 \[<=]
\fBtcp_src\ < 80 and 80 < \fBtcp_src\fR \[<=] 65535, then convert each
of the range matches into a collection of bitwise matches as explained
above in the description of \fBtcp_src\fR.
.IP \(bu
Sometimes there is a choice of which flows include a particular match.
For example, suppose that we added an extra constraint to our example,
to match on \fBip_src\fR \[mo] {\fIa\fR,\fIb\fR,\fIc\fR,\fId\fR} and
\fBip_dst\fR \[mo] {\fIe\fR,\fIf\fR,\fIg\fR,\fIh\fR} and \fBtcp_dst\fR
= \fIi\fR.  One way to implement this is to add the new constraint to
the \fBconj_id\fR flow, like this:
.RS +1in
.br
\fBconj_id=1234,tcp,tcp_dst=\fIi\fB actions=mod_nw_src:1.2.3.4,controller\fR
.br
.RE
.IP
\fIbut this is not recommended\fR because of the cost of the extra
flow table lookup.  Instead, add the constraint to the individual
flows, either in one of the dimensions or (slightly better) all of
them.
.IP \(bu
A conjunctive match must have \fIn\fR \[>=] 2 dimensions (otherwise a
conjunctive match is not necessary).  Open vSwitch enforces this.
.IP \(bu
Each dimension within a conjunctive match should ordinarily have more
than one flow.  Open vSwitch does not enforce this.
.RE
.IP
The \fBconjunction\fR action and \fBconj_id\fR field were introduced
in Open vSwitch 2.4.
.RE
.
.PP
An opaque identifier called a cookie can be used as a handle to identify
a set of flows:
.
.IP \fBcookie=\fIvalue\fR
.
A cookie can be associated with a flow using the \fBadd\-flow\fR,
\fBadd\-flows\fR, and \fBmod\-flows\fR commands.  \fIvalue\fR 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.
.
.IP \fBcookie=\fIvalue\fR\fB/\fImask\fR
.
When using NXM, the cookie can be used as a handle for querying,
modifying, and deleting flows.  \fIvalue\fR and \fImask\fR may be
supplied for the \fBdel\-flows\fR, \fBmod\-flows\fR, \fBdump\-flows\fR, and
\fBdump\-aggregate\fR commands to limit matching cookies.  A 1-bit in
\fImask\fR indicates that the corresponding bit in \fIcookie\fR must
match exactly, and a 0-bit wildcards that bit.  A mask of \-1 may be used
to exactly match a cookie.
.IP
The \fBmod\-flows\fR command can update the cookies of flows that
match a cookie by specifying the \fIcookie\fR field twice (once with a
mask for matching and once without to indicate the new value):
.RS
.IP "\fBovs\-ofctl mod\-flows br0 cookie=1,actions=normal\fR"
Change all flows' cookies to 1 and change their actions to \fBnormal\fR.
.IP "\fBovs\-ofctl mod\-flows br0 cookie=1/\-1,cookie=2,actions=normal\fR"
Update cookies with a value of 1 to 2 and change their actions to
\fBnormal\fR.
.RE
.IP
The ability to match on cookies was added in Open vSwitch 1.5.0.
.
.PP
The following additional field sets the priority for flows added by
the \fBadd\-flow\fR and \fBadd\-flows\fR commands.  For
\fBmod\-flows\fR and \fBdel\-flows\fR when \fB\-\-strict\fR is
specified, priority must match along with the rest of the flow
specification.  For \fBmod-flows\fR without \fB\-\-strict\fR,
priority is only significant if the command creates a new flow, that
is, non-strict \fBmod\-flows\fR does not match on priority and will
not change the priority of existing flows.  Other commands do not
allow priority to be specified.
.
.IP \fBpriority=\fIvalue\fR
The priority at which a wildcarded entry will match in comparison to
others.  \fIvalue\fR is a number between 0 and 65535, inclusive.  A higher 
\fIvalue\fR 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.
.IP
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.
.
.PP
The \fBadd\-flow\fR, \fBadd\-flows\fR, and \fBmod\-flows\fR commands
support the following additional options.  These options affect only
new flows.  Thus, for \fBadd\-flow\fR and \fBadd\-flows\fR, these
options are always significant, but for \fBmod\-flows\fR they are
significant only if the command creates a new flow, that is, their
values do not update or affect existing flows.
.
.IP "\fBidle_timeout=\fIseconds\fR"
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.
.
.IP \fBhard_timeout=\fIseconds\fR
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.
.
.IP "\fBimportance=\fIvalue\fR"
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.
.IP
Only OpenFlow 1.4 and later support \fBimportance\fR.
.
.IP "\fBsend_flow_rem\fR"
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.
.
.IP "\fBcheck_overlap\fR"
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.)
.
.PP
The \fBdump\-flows\fR, \fBdump\-aggregate\fR, \fBdel\-flow\fR 
and \fBdel\-flows\fR commands support one additional optional field:
.
.TP
\fBout_port=\fIport\fR
If set, a matching flow must include an output action to \fIport\fR,
which must be an OpenFlow port number or name (e.g. \fBlocal\fR).
.
.SS "Table Entry Output"
.
The \fBdump\-tables\fR and \fBdump\-aggregate\fR commands print information 
about the entries in a datapath's tables.  Each line of output is a 
flow entry as described in \fBFlow Syntax\fR, above, plus some
additional fields:
.
.IP \fBduration=\fIsecs\fR
The time, in seconds, that the entry has been in the table.
\fIsecs\fR includes as much precision as the switch provides, possibly
to nanosecond resolution.
.
.IP \fBn_packets\fR
The number of packets that have matched the entry.
.
.IP \fBn_bytes\fR
The total number of bytes from packets that have matched the entry.
.
.PP
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 \fB\-\-flow-format\fR option below).
The values of these additional fields are approximations only and in
particular \fBidle_age\fR will sometimes become nonzero even for busy
flows.
.
.IP \fBhard_age=\fIsecs\fR
The integer number of seconds since the flow was added or modified.
\fBhard_age\fR is displayed only if it differs from the integer part
of \fBduration\fR.  (This is separate from \fBduration\fR because
\fBmod\-flows\fR restarts the \fBhard_timeout\fR timer without zeroing
\fBduration\fR.)
.
.IP \fBidle_age=\fIsecs\fR
The integer number of seconds that have passed without any packets
passing through the flow.
.
.SS "Group Syntax"
.PP
Some \fBovs\-ofctl\fR commands accept an argument that describes a group or
groups.  Such flow descriptions comprise a series
\fIfield\fB=\fIvalue\fR 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.
.PP
.IP \fBgroup_id=\fIid\fR
The integer group id of group.
When this field is specified in \fBdel\-groups\fR or \fBdump\-groups\fR,
the keyword "all" may be used to designate all groups.
.
This field is required.


.IP \fBtype=\fItype\fR
The type of the group.  The \fBadd-group\fR, \fBadd-groups\fR and
\fBmod-groups\fR commands require this field.  It is prohibited for
other commands. The following keywords designated the allowed types:
.RS
.IP \fBall\fR
Execute all buckets in the group.
.IP \fBselect\fR
Execute one bucket in the group.
The switch should select the bucket in such a way that should implement
equal load sharing is achieved.  The switch may optionally select the
bucket based on bucket weights.
.IP \fBindirect\fR
Executes the one bucket in the group.
.IP \fBff\fR
.IQ \fBfast_failover\fR
Executes the first live bucket in the group which is associated with
a live port or group.
.RE

.IP \fBcommand_bucket_id=\fIid\fR
The bucket to operate on.  The \fBinsert-buckets\fR and \fBremove-buckets\fR
commands require this field.  It is prohibited for other commands.
\fIid\fR may be an integer or one of the following keywords:
.RS
.IP \fBall\fR
Operate on all buckets in the group.
Only valid when used with the \fBremove-buckets\fR command in which
case the effect is to remove all buckets from the group.
.IP \fBfirst\fR
Operate on the first bucket present in the group.
In the case of the \fBinsert-buckets\fR 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 \fBremove-buckets\fR command the effect is to
remove the first bucket of the group; or do nothing if there are no
buckets present in the group.
.IP \fBlast\fR
Operate on the last bucket present in the group.
In the case of the \fBinsert-buckets\fR 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 \fBremove-buckets\fR command the effect is to
remove the last bucket of the group; or do nothing if there are no
buckets present in the group.
.RE
.IP
If \fIid\fR is an integer then it should correspond to the \fBbucket_id\fR
of a bucket present in the group.
In case of the \fBinsert-buckets\fR command the effect is to
insert buckets just before the bucket in the group whose \fBbucket_id\fR is
\fIid\fR.
In case of the \fBiremove-buckets\fR command the effect is to
remove the in the group whose \fBbucket_id\fR is \fIid\fR.
It is an error if there is no bucket persent group in whose \fBbucket_id\fR is
\fIid\fR.

.IP \fBselection_method\fR=\fImethod\fR
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 \fBadd\-group\fR, \fBadd\-groups\fR and
\fBmod\-group\fR commands on groups of type \fBselect\fR. Prohibited
otherwise. The default value is the empty string.
.IP
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.

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

.IP \fBfields\fR=\fIparam\fR
The field parameters to selection method selected by the
\fBselection_method\fR field.  The syntax is described in \fBFlow Syntax\fR
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 \fBselection_method\fR.  They are optional if the
\fBselection_method\fR field is specified as a non-empty string.
Prohibited otherwise. The default is no fields.
.IP
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.

.IP \fBbucket\fR=\fIbucket_parameters\fR
The \fBadd-group\fR, \fBadd-groups\fR and \fBmod-group\fR 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.
.
\fIbucket_parameters\fR consists of a list of \fIfield\fB=\fIvalue\fR
assignments, separated by commas or white space followed by a
comma-separated list of actions.
The fields for \fIbucket_parameters\fR are:
.
.RS
.IP \fBbucket_id=\fIid\fR
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.
.IP \fBactions=\fR[\fIaction\fR][\fB,\fIaction\fR...]\fR
The syntax of actions are identical to the \fBactions=\fR field described in
\fBFlow Syntax\fR above. Specyfing \fBactions=\fR is optional, any unknown
bucket parameter will be interpreted as an action.
.IP \fBweight=\fIvalue\fR
The relative weight of the bucket as an integer. This may be used by the switch
during bucket select for groups whose \fBtype\fR is \fBselect\fR.
.IP \fBwatch_port=\fIport\fR
Port used to determine liveness of group.
This or the \fBwatch_group\fR field is required
for groups whose \fBtype\fR is \fBff\fR or \fBfast_failover\fR.
.IP \fBwatch_group=\fIgroup_id\fR
Group identifier of group used to determine liveness of group.
This or the \fBwatch_port\fR field is required
for groups whose \fBtype\fR is \fBff\fR or \fBfast_failover\fR.
.RE
.
.SS "Meter Syntax"
.PP
The meter table commands accept an argument that describes a meter.
Such meter descriptions comprise a series \fIfield\fB=\fIvalue\fR
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.
.PP
.IP \fBmeter=\fIid\fR
The integer meter id of the meter.
When this field is specified in \fBdel-meter\fR, \fBdump-meter\fR, or
\fBmeter-stats\fR, the keyword "all" may be used to designate all meters.
.
This field is required, exept for \fBmeter-stats\fR, which dumps all stats
when this field is not specified.

.IP \fBkbps\fR
.IQ \fBpktps\fR
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.

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

.IP \fBstats\fR
Collect meter and band statistics.

.IP \fBbands\fR=\fIband_parameters\fR
The \fBadd-meter\fR and \fBmod-meter\fR commands require at least one
band specification. Bands must appear after all other fields.
.RS
.IP \fBtype=\fItype\fR
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:
.RS
.IP \fBdrop\fR
Drop packets exceeding the band's rate limit.
.RE
.
.IP "The other \fIband_parameters\fR are:"
.IP \fBrate=\fIvalue\fR
The relative rate limit for this band, in kilobits per second or packets per
second, depending on the meter flags defined above.
.IP \fBburst_size=\fIsize\fR
The maximum burst allowed for the band.  If \fBpktps\fR is specified,
then \fIsize\fR is a packet count, otherwise it is in kilobits.  If
unspecified, the switch is free to select some reasonable value
depending on its configuration.
.RE
.
.SH OPTIONS
.TP
\fB\-\-strict\fR
Uses strict matching when running flow modification commands.
.
.IP "\fB\-\-bundle\fR"
Execute flow mods as an OpenFlow 1.4 atomic bundle transaction.
.RS
.IP \(bu
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
\fIswitch\fR'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.
.IP \(bu
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.
.IP \(bu
Bundles require OpenFlow 1.4 or higher.  An explicit \fB-O
OpenFlow14\fR option is not needed, but you may need to enable
OpenFlow 1.4 support for OVS by setting the OVSDB \fIprotocols\fR
column in the \fIbridge\fR table.
.RE
.
.so lib/ofp-version.man
.
.IP "\fB\-F \fIformat\fR[\fB,\fIformat\fR...]"
.IQ "\fB\-\-flow\-format=\fIformat\fR[\fB,\fIformat\fR...]"
\fBovs\-ofctl\fR supports the following individual flow formats, any
number of which may be listed as \fIformat\fR:
.RS
.IP "\fBOpenFlow10\-table_id\fR"
This is the standard OpenFlow 1.0 flow format.  All OpenFlow switches
and all versions of Open vSwitch support this flow format.
.
.IP "\fBOpenFlow10+table_id\fR"
This is the standard OpenFlow 1.0 flow format plus a Nicira extension
that allows \fBovs\-ofctl\fR to specify the flow table in which a
particular flow should be placed.  Open vSwitch 1.2 and later supports
this flow format.
.
.IP "\fBNXM\-table_id\fR (Nicira Extended Match)"
This Nicira extension to OpenFlow is flexible and extensible.  It
supports all of the Nicira flow extensions, such as \fBtun_id\fR and
registers.  Open vSwitch 1.1 and later supports this flow format.
.
.IP "\fBNXM+table_id\fR (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.
.
.IP "\fBOXM-OpenFlow12\fR"
.IQ "\fBOXM-OpenFlow13\fR"
.IQ "\fBOXM-OpenFlow14\fR"
These are the standard OXM (OpenFlow Extensible Match) flow format in
OpenFlow 1.2, 1.3, and 1.4, respectively.
.RE
.
.IP
\fBovs\-ofctl\fR also supports the following abbreviations for
collections of flow formats:
.RS
.IP "\fBany\fR"
Any supported flow format.
.IP "\fBOpenFlow10\fR"
\fBOpenFlow10\-table_id\fR or \fBOpenFlow10+table_id\fR.
.IP "\fBNXM\fR"
\fBNXM\-table_id\fR or \fBNXM+table_id\fR.
.IP "\fBOXM\fR"
\fBOXM-OpenFlow12\fR, \fBOXM-OpenFlow13\fR, or \fBOXM-OpenFlow14\fR.
.RE
.
.IP
For commands that modify the flow table, \fBovs\-ofctl\fR by default
negotiates the most widely supported flow format that supports the
flows being added.  For commands that query the flow table,
\fBovs\-ofctl\fR by default uses the most advanced format supported by
the switch.
.IP
This option, where \fIformat\fR is a comma-separated list of one or
more of the formats listed above, limits \fBovs\-ofctl\fR's choice of
flow format.  If a command cannot work as requested using one of the
specified flow formats, \fBovs\-ofctl\fR will report a fatal error.
.
.IP "\fB\-P \fIformat\fR"
.IQ "\fB\-\-packet\-in\-format=\fIformat\fR"
\fBovs\-ofctl\fR supports the following packet_in formats, in order of
increasing capability:
.RS
.IP "\fBopenflow10\fR"
This is the standard OpenFlow 1.0 packet in format. It should be supported by
all OpenFlow switches.
.
.IP "\fBnxm\fR (Nicira Extended Match)"
This packet_in format includes flow metadata encoded using the NXM format.
.
.RE
.IP
Usually, \fBovs\-ofctl\fR prefers the \fBnxm\fR packet_in format, but will
allow the switch to choose its default if \fBnxm\fR is unsupported.  When
\fIformat\fR is one of the formats listed in the above table, \fBovs\-ofctl\fR
will insist on the selected format.  If the switch does not support the
requested format, \fBovs\-ofctl\fR will report a fatal error.  This option only
affects the \fBmonitor\fR command.
.
.IP "\fB\-\-timestamp\fR"
Print a timestamp before each received packet.  This option only
affects the \fBmonitor\fR, \fBsnoop\fR, and \fBofp\-parse\-pcap\fR
commands.
.
.IP "\fB\-m\fR"
.IQ "\fB\-\-more\fR"
Increases the verbosity of OpenFlow messages printed and logged by
\fBovs\-ofctl\fR commands.  Specify this option more than once to
increase verbosity further.
.
.IP \fB\-\-sort\fR[\fB=\fIfield\fR]
.IQ \fB\-\-rsort\fR[\fB=\fIfield\fR]
Display output sorted by flow \fIfield\fR in ascending
(\fB\-\-sort\fR) or descending (\fB\-\-rsort\fR) order, where
\fIfield\fR is any of the fields that are allowed for matching or
\fBpriority\fR to sort by priority.  When \fIfield\fR is omitted, the
output is sorted by priority.  Specify these options multiple times to
sort by multiple fields.
.IP
Any given flow will not necessarily specify a value for a given
field.  This requires special treatement:
.RS
.IP \(bu
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,
\fB\-\-sort=tcp_src\fR 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.
.IP \(bu
A flow that only specifies some bits in a field is sorted as if the
wildcarded bits were zero.  For example, \fB\-\-sort=nw_src\fR would
sort a flow that specifies \fBnw_src=192.168.0.0/24\fR the same as
\fBnw_src=192.168.0.0\fR.
.RE
.IP
These options currently affect only \fBdump\-flows\fR output.
.
.ds DD \
\fBovs\-ofctl\fR detaches only when executing the \fBmonitor\fR or \
\fBsnoop\fR commands.
.so lib/daemon.man
.so lib/unixctl.man
.SS "Public Key Infrastructure Options"
.so lib/ssl.man
.so lib/vlog.man
.so lib/common.man
.
.SH "RUNTIME MANAGEMENT COMMANDS"
\fBovs\-appctl\fR(8) can send commands to a running \fBovs\-ofctl\fR
process.  The supported commands are listed below.
.
.IP "\fBexit\fR"
Causes \fBovs\-ofctl\fR to gracefully terminate.  This command applies
only when executing the \fBmonitor\fR or \fBsnoop\fR commands.
.
.IP "\fBofctl/set\-output\-file \fIfile\fR"
Causes all subsequent output to go to \fIfile\fR instead of stderr.
This command applies only when executing the \fBmonitor\fR or
\fBsnoop\fR commands.
.
.IP "\fBofctl/send \fIofmsg\fR..."
Sends each \fIofmsg\fR, specified as a sequence of hex digits that
express an OpenFlow message, on the OpenFlow connection.  This command
is useful only when executing the \fBmonitor\fR command.
.
.IP "\fBofctl/barrier\fR"
Sends an OpenFlow barrier request on the OpenFlow connection and waits
for a reply.  This command is useful only for the \fBmonitor\fR
command.
.
.SH EXAMPLES
.
The following examples assume that \fBovs\-vswitchd\fR has a bridge
named \fBbr0\fR configured.
.
.TP
\fBovs\-ofctl dump\-tables br0\fR
Prints out the switch's table stats.  (This is more interesting after
some traffic has passed through.)
.
.TP
\fBovs\-ofctl dump\-flows br0\fR
Prints the flow entries in the switch.
.
.SH "SEE ALSO"
.
.BR ovs\-appctl (8),
.BR ovs\-vswitchd (8)
.BR ovs\-vswitchd.conf.db (8)