The ovs-ofctl program is a command line tool for monitoring
and administering OpenFlow switches. It can also show the current state of
an OpenFlow switch, including features, configuration, and table entries. It
should work with any OpenFlow switch, not just Open vSwitch.
These commands allow ovs-ofctl to monitor and administer an
OpenFlow switch. It is able to show the current state of a switch, including
features, configuration, and table entries.
Most of these commands take an argument that specifies the method
for connecting to an OpenFlow switch. The following connection methods are
supported:
- ssl:host[:port]
-
- tcp:host[:port]
- The specified port on the given host, which can be expressed
either as a DNS name (if built with unbound library) or an IP address in
IPv4 or IPv6 address format. Wrap IPv6 addresses in square brackets, e.g.
tcp:[::1]:6653. On Linux, use %device to designate a
scope for IPv6 link-level addresses, e.g.
tcp:[fe80::1234%eth0]:6653. For ssl, the
--private-key, --certificate, and --ca-cert options
are mandatory.
- If port is not specified, it defaults to 6653.
- unix:file
- On POSIX, a Unix domain server socket named file.
- On Windows, connect to a local named pipe that is represented by a file
created in the path file to mimic the behavior of a Unix domain
socket.
- file
- This is short for unix:file, as long as file does not
contain a colon.
- bridge
- This is short for
unix:/var/run/openvswitch/bridge.mgmt, as long as
bridge does not contain a colon.
- [type@]dp
- Attempts to look up the bridge associated with dp and open as
above. If type is given, it specifies the datapath provider of
dp, otherwise the default provider system is assumed.
- show
switch
- Prints to the console information on switch, including information
on its flow tables and ports.
- dump-tables
switch
- Prints to the console statistics for each of the flow tables used by
switch.
- dump-table-features
switch
- Prints to the console features for each of the flow tables used by
switch.
- dump-table-desc
switch
- Prints to the console configuration for each of the flow tables used by
switch for OpenFlow 1.4+.
- mod-table switch
table setting
- This command configures flow table settings in switch for OpenFlow
table table, which may be expressed as a number or (unless
--no-names is specified) a name.
- The available settings depend on the OpenFlow version in use. In OpenFlow
1.1 and 1.2 (which must be enabled with the -O option) only,
mod-table configures behavior when no flow is found when a packet
is looked up in a flow table. The following setting values are
available:
- drop
- Drop the packet.
- continue
- Continue to the next table in the pipeline. (This is how an OpenFlow 1.0
switch always handles packets that do not match any flow, in tables other
than the last one.)
- controller
- Send to controller. (This is how an OpenFlow 1.0 switch always handles
packets that do not match any flow in the last table.)
- In OpenFlow 1.3 and later (which must be enabled with the -O
option) and Open vSwitch 2.11 and later only, mod-table can change
the name of a table:
- name:new-name
- Changes the name of the table to new-name. Use an empty
new-name to clear the name. (This will be ineffective if the name
is set via the name column in the Flow_Table table in the
Open_vSwitch database as described in
ovs-vswitchd.conf.db(5).)
- In OpenFlow 1.4 and later (which must be enabled with the -O
option) only, mod-table configures the behavior when a controller
attempts to add a flow to a flow table that is full. The following
setting values are available:
- evict
- Delete some existing flow from the flow table, according to the algorithm
described for the Flow_Table table in
ovs-vswitchd.conf.db(5).
- noevict
- Refuse to add the new flow. (Eviction might still be enabled through the
overflow_policy column in the Flow_Table table documented in
ovs-vswitchd.conf.db(5).)
- vacancy:low,high
- Enables sending vacancy events to controllers using TABLE_STATUS
messages, based on percentage thresholds low and high.
- novacancy
- Disables vacancy events.
- dump-ports
switch [netdev]
- Prints to the console statistics for network devices associated with
switch. If netdev is specified, only the statistics
associated with that device will be printed. netdev can be an
OpenFlow assigned port number or device name, e.g. eth0.
- dump-ports-desc
switch [port]
- Prints to the console detailed information about network devices
associated with switch. To dump only a specific port, specify its
number as port. Otherwise, if port is omitted, or if it is
specified as ANY, then all ports are printed. This is a subset of
the information provided by the show command.
- If the connection to switch negotiates OpenFlow 1.0, 1.2, or 1.2,
this command uses an OpenFlow extension only implemented in Open vSwitch
(version 1.7 and later).
- Only OpenFlow 1.5 and later support dumping a specific port. Earlier
versions of OpenFlow always dump all ports.
- mod-port
switch port action
- Modify characteristics of port port in switch. port
may be an OpenFlow port number or name (unless --no-names is
specified) or the keyword LOCAL (the preferred way to refer to the
OpenFlow local port). The action may be any one of the
following:
- up
-
- down
- Enable or disable the interface. This is equivalent to ip link
set up or ip link set down on a Unix system.
- stp
-
- no-stp
- Enable or disable 802.1D spanning tree protocol (STP) on the interface.
OpenFlow implementations that don't support STP will refuse to enable
it.
- receive
-
- no-receive
-
- receive-stp
-
- no-receive-stp
- Enable or disable OpenFlow processing of packets received on this
interface. When packet processing is disabled, packets will be dropped
instead of being processed through the OpenFlow table. The receive
or no-receive setting applies to all packets except 802.1D spanning
tree packets, which are separately controlled by receive-stp or
no-receive-stp.
- forward
-
- no-forward
- Allow or disallow forwarding of traffic to this interface. By default,
forwarding is enabled.
- flood
-
- no-flood
- Controls whether an OpenFlow flood action will send traffic out
this interface. By default, flooding is enabled. Disabling flooding is
primarily useful to prevent loops when a spanning tree protocol is not in
use.
- packet-in
-
- no-packet-in
- Controls whether packets received on this interface that do not match a
flow table entry generate a ``packet in'' message to the OpenFlow
controller. By default, ``packet in'' messages are enabled.
- The show command displays (among other information) the
configuration that mod-port changes.
- get-frags
switch
- Prints switch's fragment handling mode. See set-frags,
below, for a description of each fragment handling mode.
- The show command also prints the fragment handling mode among its
other output.
- set-frags switch
frag_mode
- Configures switch's treatment of IPv4 and IPv6 fragments. The
choices for frag_mode are:
- normal
- Fragments pass through the flow table like non-fragmented packets. The TCP
ports, UDP ports, and ICMP type and code fields are always set to 0, even
for fragments where that information would otherwise be available
(fragments with offset 0). This is the default fragment handling mode for
an OpenFlow switch.
- drop
- Fragments are dropped without passing through the flow table.
- reassemble
- The switch reassembles fragments into full IP packets before passing them
through the flow table. Open vSwitch does not implement this fragment
handling mode.
- nx-match
- Fragments pass through the flow table like non-fragmented packets. The TCP
ports, UDP ports, and ICMP type and code fields are available for matching
for fragments with offset 0, and set to 0 in fragments with nonzero
offset. This mode is a Nicira extension.
- See the description of ip_frag, in ovs-fields(7), for a way
to match on whether a packet is a fragment and on its fragment
offset.
- dump-flows
switch [flows]
- Prints to the console all flow entries in switch's tables that
match flows. If flows is omitted, all flows in the switch
are retrieved. See Flow Syntax, below, for the syntax of
flows. The output format is described in Table Entry
Output.
- By default, ovs-ofctl prints flow entries in the same order that
the switch sends them, which is unlikely to be intuitive or consistent.
Use --sort and --rsort to control display order. The
--names/--no-names and --stats/--no-stats
options also affect output formatting. See the descriptions of these
options, under OPTIONS below, for more information
- dump-aggregate
switch [flows]
- Prints to the console aggregate statistics for flows in switch's
tables that match flows. If flows is omitted, the statistics
are aggregated across all flows in the switch's flow tables. See Flow
Syntax, below, for the syntax of flows. The output format is
described in Table Entry Output.
- queue-stats switch
[port [queue]]
- Prints to the console statistics for the specified queue on
port within switch. port can be an OpenFlow port
number or name, the keyword LOCAL (the preferred way to refer to
the OpenFlow local port), or the keyword ALL. Either of port
or queue or both may be omitted (or equivalently the keyword
ALL). If both are omitted, statistics are printed for all queues on
all ports. If only queue is omitted, then statistics are printed
for all queues on port; if only port is omitted, then
statistics are printed for queue on every port where it
exists.
- queue-get-config
switch [port [queue]]
- Prints to the console the configuration of queue on port in
switch. If port is omitted or ANY, reports queues for
all port. If queue is omitted or ANY, reports all queues.
For OpenFlow 1.3 and earlier, the output always includes all queues,
ignoring queue if specified.
- This command has limited usefulness, because ports often have no
configured queues and because the OpenFlow protocol provides only very
limited information about the configuration of a queue.
- dump-ipfix-bridge
switch
- Prints to the console the statistics of bridge IPFIX for switch. If
bridge IPFIX is configured on the switch, IPFIX statistics can be
retrieved. Otherwise, error message will be printed.
- This command uses an Open vSwitch extension that is only in Open vSwitch
2.6 and later.
- dump-ipfix-flow
switch
- Prints to the console the statistics of flow-based IPFIX for
switch. If flow-based IPFIX is configured on the switch,
statistics of all the collector set ids on the switch will be
printed. Otherwise, print error message.
- Refer to ovs-vswitchd.conf.db(5) for more details on configuring
flow based IPFIX and collector set ids.
- This command uses an Open vSwitch extension that is only in Open vSwitch
2.6 and later.
- ct-flush-zone switch
zone
- Flushes the connection tracking entries in zone on
switch.
- This command uses an Open vSwitch extension that is only in Open vSwitch
2.6 and later.
These commands manage the flow table in an OpenFlow switch. In
each case, flow specifies a flow entry in the format described in
Flow Syntax, below, file is a text file that contains zero or
more flows in the same syntax, one per line, and the optional
--bundle option operates the command as a single atomic transation,
see option --bundle, below.
- [--bundle] add-flow switch flow
-
- [--bundle] add-flow switch - <
file
-
- [--bundle] add-flows switch file
- Add each flow entry to switch's tables. Each flow specification
(e.g., each line in file) may start with add, modify,
delete, modify_strict, or delete_strict keyword to
specify whether a flow is to be added, modified, or deleted, and whether
the modify or delete is strict or not. For backwards compatibility a flow
specification without one of these keywords is treated as a flow add. All
flow mods are executed in the order specified.
- [--bundle] [--strict] mod-flows switch
flow
-
- [--bundle] [--strict] mod-flows switch -
< file
- Modify the actions in entries from switch's tables that match the
specified flows. With --strict, wildcards are not treated as active
for matching purposes.
- [--bundle] del-flows switch
-
- [--bundle] [--strict] del-flows switch
[flow]
-
- [--bundle] [--strict] del-flows switch -
< file
- Deletes entries from switch's flow table. With only a switch
argument, deletes all flows. Otherwise, deletes flow entries that match
the specified flows. With --strict, wildcards are not treated as
active for matching purposes.
- [--bundle] [--readd] replace-flows switch
file
- Reads flow entries from file (or stdin if file is
-) and queries the flow table from switch. Then it fixes up
any differences, adding flows from flow that are missing on
switch, deleting flows from switch that are not in
file, and updating flows in switch whose actions, cookie, or
timeouts differ in file.
- With --readd, ovs-ofctl adds all the flows from file,
even those that exist with the same actions, cookie, and timeout in
switch. In OpenFlow 1.0 and 1.1, re-adding a flow always resets the
flow's packet and byte counters to 0, and in OpenFlow 1.2 and later, it
does so only if the reset_counts flag is set.
- diff-flows source1
source2
- Reads flow entries from source1 and source2 and prints the
differences. A flow that is in source1 but not in source2 is
printed preceded by a -, and a flow that is in source2 but
not in source1 is printed preceded by a +. If a flow exists
in both source1 and source2 with different actions, cookie,
or timeouts, then both versions are printed preceded by - and
+, respectively.
- source1 and source2 may each name a file or a switch. If a
name begins with / or ., then it is considered to be a file
name. A name that contains : is considered to be a switch.
Otherwise, it is a file if a file by that name exists, a switch if
not.
- For this command, an exit status of 0 means that no differences were
found, 1 means that an error occurred, and 2 means that some differences
were found.
- packet-out
switch packet-out
- Connects to switch and instructs it to execute the
packet-out OpenFlow message, specified as defined in Packet-Out
Syntax section.
These commands manage the group table in an OpenFlow switch. In
each case, group specifies a group entry in the format described in
Group Syntax, below, and file is a text file that contains
zero or more groups in the same syntax, one per line, and the optional
--bundle option operates the command as a single atomic transation,
see option --bundle, below.
The group commands work only with switches that support OpenFlow
1.1 or later or the Open vSwitch group extensions to OpenFlow 1.0 (added in
Open vSwitch 2.9.90). For OpenFlow 1.1 or later, it is necessary to
explicitly enable these protocol versions in ovs-ofctl (using
-O). For more information, see ``Q: What versions of OpenFlow does
Open vSwitch support?'' in the Open vSwitch FAQ.
- [--bundle] add-group switch group
-
- [--bundle] add-group switch - <
file
-
- [--bundle] add-groups switch file
- Add each group entry to switch's tables. Each group specification
(e.g., each line in file) may start with add, modify,
add_or_mod, delete, insert_bucket, or
remove_bucket keyword to specify whether a flow is to be added,
modified, or deleted, or whether a group bucket is to be added or removed.
For backwards compatibility a group specification without one of these
keywords is treated as a group add. All group mods are executed in the
order specified.
- [--bundle] [--may-create] mod-group switch
group
-
- [--bundle] [--may-create] mod-group switch
- < file
- Modify the action buckets in entries from switch's tables for each
group entry. If a specified group does not already exist, then without
--may-create, this command has no effect; with --may-create,
it creates a new group. The --may-create option uses an Open
vSwitch extension to OpenFlow only implemented in Open vSwitch 2.6 and
later.
- [--bundle] del-groups switch
-
- [--bundle] del-groups switch [group]
-
- [--bundle] del-groups switch - <
file
- Deletes entries from switch's group table. With only a
switch argument, deletes all groups. Otherwise, deletes the group
for each group entry.
- [--bundle] insert-buckets switch group
-
- [--bundle] insert-buckets switch - <
file
- Add buckets to an existing group present in the switch's group
table. If no command_bucket_id is present in the group
specification then all buckets of the group are removed.
- [--bundle] remove-buckets switch group
-
- [--bundle] remove-buckets switch - <
file
- Remove buckets to an existing group present in the switch's group
table. If no command_bucket_id is present in the group
specification then all buckets of the group are removed.
- dump-groups
switch [group]
- Prints group entries in switch's tables to console. To dump only a
specific group, specify its number as group. Otherwise, if
group is omitted, or if it is specified as ALL, then all
groups are printed.
- Only OpenFlow 1.5 and later support dumping a specific group. Earlier
versions of OpenFlow always dump all groups.
- dump-group-features
switch
- Prints to the console the group features of the switch.
- dump-group-stats
switch [group]
- Prints to the console statistics for the specified group in
switch's tables. If group is omitted then statistics for all
groups are printed.
These commands manage the meter table in an OpenFlow switch. In
each case, meter specifies a meter entry in the format described in
Meter Syntax, below.
OpenFlow 1.3 introduced support for meters, so these commands only
work with switches that support OpenFlow 1.3 or later. It is necessary to
explicitly enable these protocol versions in ovs-ofctl (using
-O) and in the switch itself (with the protocols column in the
Bridge table). For more information, see ``Q: What versions of
OpenFlow does Open vSwitch support?'' in the Open vSwitch FAQ.
- add-meter switch
meter
- Add a meter entry to switch's tables. The meter syntax is
described in section Meter Syntax, below.
- mod-meter switch
meter
- Modify an existing meter.
- del-meters switch
[meter]
- Delete entries from switch's meter table. To delete only a specific
meter, specify its number as meter. Otherwise, if meter is
omitted, or if it is specified as all, then all meters are
deleted.
- dump-meters
switch [meter]
- Print entries from switch's meter table. To print only a specific
meter, specify its number as meter. Otherwise, if meter is
omitted, or if it is specified as all, then all meters are
printed.
- meter-stats
switch [meter]
- Print meter statistics. meter can specify a single meter with
syntax meter=id, or all meters with syntax
meter=all.
- meter-features
switch
- Print meter features.
Transactional updates to both flow and group tables can be made
with the bundle command. file is a text file that contains
zero or more flow mods, group mods, or packet-outs in Flow
Syntax, Group Syntax, or Packet-Out Syntax, each line
preceded by flow, group, or packet-out keyword,
correspondingly. The flow keyword may be optionally followed by one
of the keywords add, modify, modify_strict,
delete, or delete_strict, of which the add is assumed
if a bare flow is given. Similarly, the group keyword may be
optionally followed by one of the keywords add, modify,
add_or_mod, delete, insert_bucket, or
remove_bucket, of which the add is assumed if a bare
group is given.
- bundle switch
file
- Execute all flow and group mods in file as a single atomic
transaction against switch's tables. All bundled mods are executed
in the order specified.
Open vSwitch maintains a mapping table between tunnel option TLVs
(defined by <class, type, length>) and NXM fields
tun_metadatan, where n ranges from 0 to 63, that can be
operated on for the purposes of matches, actions, etc. This TLV table can be
used for Geneve option TLVs or other protocols with options in same TLV
format as Geneve options. This mapping must be explicitly specified by the
user through the following commands.
A TLV mapping is specified with the syntax
{class=class,type=type,len=length}->tun_metadatan.
When an option mapping exists for a given tun_metadatan,
matching on the defined field becomes possible, e.g.:
ovs-ofctl add-tlv-map br0
"{class=0xffff,type=0,len=4}->tun_metadata0"
ovs-ofctl add-flow br0 tun_metadata0=1234,actions=controller
A mapping should not be changed while it is in active use by a
flow. The result of doing so is undefined.
These commands are Nicira extensions to OpenFlow and require Open
vSwitch 2.5 or later.
- add-tlv-map switch
option[,option]...
- Add each option to switch's tables. Duplicate fields are
rejected.
- del-tlv-map switch
[option[,option]]...
- Delete each option from switch's table, or all option TLV
mapping if no option is specified. Fields that aren't mapped are
ignored.
- dump-tlv-map
switch
- Show the currently mapped fields in the switch's option table as well as
switch capabilities.
- snoop
switch
- Connects to switch and prints to the console all OpenFlow messages
received. Unlike other ovs-ofctl commands, if switch is the
name of a bridge, then the snoop command connects to a Unix domain
socket named /var/run/openvswitch/switch.snoop.
ovs-vswitchd listens on such a socket for each bridge and sends to
it all of the OpenFlow messages sent to or received from its configured
OpenFlow controller. Thus, this command can be used to view OpenFlow
protocol activity between a switch and its controller.
- When a switch has more than one controller configured, only the traffic to
and from a single controller is output. If none of the controllers is
configured as a primary or a secondary (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 primary
controller, it is chosen; otherwise, if there are any controllers that are
not primaries or secondaries, one is chosen arbitrarily; otherwise, a
secondary controller is chosen arbitrarily. This choice is made once at
connection time and does not change as controllers reconfigure their
roles.
- If a switch has no controller configured, or if the configured controller
is disconnected, no traffic is sent, so monitoring will not show any
traffic.
- monitor
switch [miss-len] [invalid_ttl]
[watch:[spec...]]
- Connects to switch and prints to the console all OpenFlow messages
received. Usually, switch should specify the name of a bridge in
the ovs-vswitchd database. This is available only in OpenFlow 1.0
as Nicira extension.
- If miss-len is provided, ovs-ofctl sends an OpenFlow ``set
configuration'' message at connection setup time that requests
miss-len bytes of each packet that misses the flow table. Open
vSwitch does not send these and other asynchronous messages to an
ovs-ofctl monitor client connection unless a nonzero value is
specified on this argument. (Thus, if miss-len is not specified,
very little traffic will ordinarily be printed.)
- If invalid_ttl is passed, ovs-ofctl sends an OpenFlow ``set
configuration'' message at connection setup time that requests
INVALID_TTL_TO_CONTROLLER, so that ovs-ofctl monitor can
receive ``packet-in'' messages when TTL reaches zero on dec_ttl
action. Only OpenFlow 1.1 and 1.2 support invalid_ttl; Open vSwitch
also implements it for OpenFlow 1.0 as an extension.
- watch:[spec...] causes ovs-ofctl to send a
``monitor request'' Nicira extension message to the switch at connection
setup time. This message causes the switch to send information about flow
table changes as they occur. The following comma-separated spec
syntax is available:
- !initial
- Do not report the switch's initial flow table contents.
- !add
- Do not report newly added flows.
- !delete
- Do not report deleted flows.
- !modify
- Do not report modifications to existing flows.
- !own
- Abbreviate changes made to the flow table by ovs-ofctl's own
connection to the switch. (These could only occur using the
ofctl/send command described below under RUNTIME MANAGEMENT
COMMANDS.)
- !actions
- Do not report actions as part of flow updates.
- table=table
- Limits the monitoring to the table with the given table, which may
be expressed as a number between 0 and 254 or (unless --no-names is
specified) a name. By default, all tables are monitored.
- out_port=port
- If set, only flows that output to port are monitored. The
port may be an OpenFlow port number or keyword (e.g.
LOCAL).
- field=value
- Monitors only flows that have field specified as the given
value. Any syntax valid for matching on dump-flows may be
used.
- This command may be useful for debugging switch or controller
implementations. With watch:, it is particularly useful for
observing how a controller updates flow tables.
The following commands, like those in the previous section, may be
applied to OpenFlow switches, using any of the connection methods described
in that section. Unlike those commands, these may also be applied to
OpenFlow controllers.
- probe
target
- Sends a single OpenFlow echo-request message to target and waits
for the response. With the -t or --timeout option, this
command can test whether an OpenFlow switch or controller is up and
running.
- ping target
[n]
- Sends a series of 10 echo request packets to target and times each
reply. The echo request packets consist of an OpenFlow header plus
n bytes (default: 64) of randomly generated payload. This measures
the latency of individual requests.
- benchmark
target n count
- Sends count echo request packets that each consist of an OpenFlow
header plus n bytes of payload and waits for each response. Reports
the total time required. This is a measure of the maximum bandwidth to
target for round-trips of n-byte messages.
- ofp-parse
file
- Reads file (or stdin if file is -) as a series
of OpenFlow messages in the binary format used on an OpenFlow connection,
and prints them to the console. This can be useful for printing OpenFlow
messages captured from a TCP stream.
- ofp-parse-pcap
file [port...]
- Reads file, which must be in the PCAP format used by network
capture tools such as tcpdump or wireshark, extracts all the
TCP streams for OpenFlow connections, and prints the OpenFlow messages in
those connections in human-readable format on stdout.
- OpenFlow connections are distinguished by TCP port number. Non-OpenFlow
packets are ignored. By default, data on TCP ports 6633 and 6653 are
considered to be OpenFlow. Specify one or more port arguments to
override the default.
- This command cannot usefully print SSL encrypted traffic. It does not
understand IPv6.
Some ovs-ofctl commands accept an argument that describes a
flow or flows. Such flow descriptions comprise a series of
field=value assignments, separated by commas or white
space. (Embedding spaces into a flow description normally requires quoting
to prevent the shell from breaking the description into multiple
arguments.)
Flow descriptions should be in normal form. This means that
a flow may only specify a value for an L3 field if it also specifies a
particular L2 protocol, and that a flow may only specify an L4 field if it
also specifies particular L2 and L3 protocol types. For example, if the L2
protocol type dl_type is wildcarded, then L3 fields nw_src,
nw_dst, and nw_proto must also be wildcarded. Similarly, if
dl_type or nw_proto (the L3 protocol type) is wildcarded, so
must be the L4 fields tcp_dst and tcp_src. ovs-ofctl
will warn about flows not in normal form.
ovs-fields(7) describes the supported fields and how to
match them. In addition to match fields, commands that operate on flows
accept a few additional key-value pairs:
- table=table
- For flow dump commands, limits the flows dumped to those in table,
which may be expressed as a number between 0 and 255 or (unless
--no-names is specified) a name. If not specified (or if 255 is
specified as table), then flows in all tables are dumped.
- For flow table modification commands, behavior varies based on the
OpenFlow version used to connect to the switch:
- OpenFlow 1.0
- OpenFlow 1.0 does not support table for modifying flows.
ovs-ofctl will exit with an error if table (other than
table=255) is specified for a switch that only supports OpenFlow
1.0.
- In OpenFlow 1.0, the switch chooses the table into which to insert a new
flow. The Open vSwitch software switch always chooses table 0. Other Open
vSwitch datapaths and other OpenFlow implementations may choose different
tables.
- The OpenFlow 1.0 behavior in Open vSwitch for modifying or removing flows
depends on whether --strict is used. Without --strict, the
command applies to matching flows in all tables. With --strict, the
command will operate on any single matching flow in any table; it will do
nothing if there are matches in more than one table. (The distinction
between these behaviors only matters if non-OpenFlow 1.0 commands were
also used, because OpenFlow 1.0 alone cannot add flows with the same
matching criteria to multiple tables.)
- OpenFlow 1.0 with
table_id extension
- Open vSwitch implements an OpenFlow extension that allows the controller
to specify the table on which to operate. ovs-ofctl automatically
enables the extension when table is specified and OpenFlow 1.0 is
used. ovs-ofctl automatically detects whether the switch supports
the extension. As of this writing, this extension is only known to be
implemented by Open vSwitch.
- With this extension, ovs-ofctl operates on the requested table when
table is specified, and acts as described for OpenFlow 1.0 above
when no table is specified (or for table=255).
- OpenFlow
1.1
- OpenFlow 1.1 requires flow table modification commands to specify a table.
When table is not specified (or table=255 is specified),
ovs-ofctl defaults to table 0.
- OpenFlow 1.2 and
later
- OpenFlow 1.2 and later allow flow deletion commands, but not other flow
table modification commands, to operate on all flow tables, with the
behavior described above for OpenFlow 1.0.
- duration=...
-
- n_packet=...
-
- n_bytes=...
- ovs-ofctl ignores assignments to these ``fields'' to allow output
from the dump-flows command to be used as input for other commands
that parse flows.
The add-flow, add-flows, and mod-flows
commands require an additional field, which must be the final field
specified:
- actions=[action][,action...]
- Specifies a comma-separated list of actions to take on a packet when the
flow entry matches. If no action is specified, then packets
matching the flow are dropped. See ovs-actions(7) for details on
the syntax and semantics of actions. K
An opaque identifier called a cookie can be used as a handle to
identify a set of flows:
- cookie=value
- A cookie can be associated with a flow using the add-flow,
add-flows, and mod-flows commands. value can be any
64-bit number and need not be unique among flows. If this field is
omitted, a default cookie value of 0 is used.
- cookie=value/mask
- When using NXM, the cookie can be used as a handle for querying,
modifying, and deleting flows. value and mask may be
supplied for the del-flows, mod-flows, dump-flows,
and dump-aggregate commands to limit matching cookies. A 1-bit in
mask indicates that the corresponding bit in cookie must
match exactly, and a 0-bit wildcards that bit. A mask of -1 may be used to
exactly match a cookie.
- The mod-flows command can update the cookies of flows that match a
cookie by specifying the cookie field twice (once with a mask for
matching and once without to indicate the new value):
- The ability to match on cookies was added in Open vSwitch 1.5.0.
The following additional field sets the priority for flows added
by the add-flow and add-flows commands. For mod-flows
and del-flows when --strict is specified, priority must match
along with the rest of the flow specification. For mod-flows without
--strict, priority is only significant if the command creates a new
flow, that is, non-strict mod-flows does not match on priority and
will not change the priority of existing flows. Other commands do not allow
priority to be specified.
- priority=value
- The priority at which a wildcarded entry will match in comparison to
others. value is a number between 0 and 65535, inclusive. A higher
value will match before a lower one. An exact-match entry will
always have priority over an entry containing wildcards, so it has an
implicit priority value of 65535. When adding a flow, if the field is not
specified, the flow's priority will default to 32768.
- OpenFlow leaves behavior undefined when two or more flows with the same
priority can match a single packet. Some users expect ``sensible''
behavior, such as more specific flows taking precedence over less specific
flows, but OpenFlow does not specify this and Open vSwitch does not
implement it. Users should therefore take care to use priorities to ensure
the behavior that they expect.
The add-flow, add-flows, and mod-flows
commands support the following additional options. These options affect only
new flows. Thus, for add-flow and add-flows, these options are
always significant, but for mod-flows they are significant only if
the command creates a new flow, that is, their values do not update or
affect existing flows.
- idle_timeout=seconds
- Causes the flow to expire after the given number of seconds of inactivity.
A value of 0 (the default) prevents a flow from expiring due to
inactivity.
- hard_timeout=seconds
- Causes the flow to expire after the given number of seconds, regardless of
activity. A value of 0 (the default) gives the flow no hard expiration
deadline.
- importance=value
- Sets the importance of a flow. The flow entry eviction mechanism can use
importance as a factor in deciding which flow to evict. A value of 0 (the
default) makes the flow non-evictable on the basis of importance. Specify
a value between 0 and 65535.
- Only OpenFlow 1.4 and later support importance.
- send_flow_rem
- Marks the flow with a flag that causes the switch to generate a ``flow
removed'' message and send it to interested controllers when the flow
later expires or is removed.
- check_overlap
- Forces the switch to check that the flow match does not overlap that of
any different flow with the same priority in the same table. (This check
is expensive so it is best to avoid it.)
- reset_counts
- When this flag is specified on a flow being added to a switch, and the
switch already has a flow with an identical match, an OpenFlow 1.2 (or
later) switch resets the flow's packet and byte counters to 0. Without the
flag, the packet and byte counters are preserved.
- OpenFlow 1.0 and 1.1 switches always reset counters in this situation, as
if reset_counts were always specified.
- Open vSwitch 1.10 added support for reset_counts.
- no_packet_counts
-
- no_byte_counts
- Adding these flags to a flow advises an OpenFlow 1.3 (or later) switch
that the controller does not need packet or byte counters, respectively,
for the flow. Some switch implementations might achieve higher performance
or reduce resource consumption when these flags are used. These flags
provide no benefit to the Open vSwitch software switch
implementation.
- OpenFlow 1.2 and earlier do not support these flags.
- Open vSwitch 1.10 added support for no_packet_counts and
no_byte_counts.
The dump-flows, dump-aggregate, del-flow and
del-flows commands support these additional optional fields:
- out_port=port
- If set, a matching flow must include an output action to port,
which must be an OpenFlow port number or name (e.g. local).
- out_group=group
- If set, a matching flow must include an group action naming
group, which must be an OpenFlow group number. This field is
supported in Open vSwitch 2.5 and later and requires OpenFlow 1.1 or
later.
The dump-tables and dump-aggregate commands print
information about the entries in a datapath's tables. Each line of output is
a flow entry as described in Flow Syntax, above, plus some additional
fields:
- duration=secs
- The time, in seconds, that the entry has been in the table. secs
includes as much precision as the switch provides, possibly to nanosecond
resolution.
- n_packets
- The number of packets that have matched the entry.
- n_bytes
- The total number of bytes from packets that have matched the entry.
The following additional fields are included only if the switch is
Open vSwitch 1.6 or later and the NXM flow format is used to dump the flow
(see the description of the --flow-format option below). The values
of these additional fields are approximations only and in particular
idle_age will sometimes become nonzero even for busy flows.
- hard_age=secs
- The integer number of seconds since the flow was added or modified.
hard_age is displayed only if it differs from the integer part of
duration. (This is separate from duration because
mod-flows restarts the hard_timeout timer without zeroing
duration.)
- idle_age=secs
- The integer number of seconds that have passed without any packets passing
through the flow.
ovs-ofctl bundle command accepts packet-outs to be
specified in the bundle file. Each packet-out comprises of a series of
field=value assignments, separated by commas or white
space. (Embedding spaces into a packet-out description normally requires
quoting to prevent the shell from breaking the description into multiple
arguments.). Unless noted otherwise only the last instance of each field is
honoured. This same syntax is also supported by the ovs-ofctl
packet-out command.
- in_port=port
- The port number to be considered the in_port when processing actions. This
can be any valid OpenFlow port number, or any of the LOCAL,
CONTROLLER, or NONE. This field is required.
- pipeline_field=value
- Optionally, user can specify a list of pipeline fields for a packet-out
message. The supported pipeline fields includes tunnel fields and
register fields as defined in ovs-fields(7).
- packet=hex-string
- The actual packet to send, expressed as a string of hexadecimal bytes.
This field is required.
- actions=[action][,action...]
- The syntax of actions are identical to the actions= field described
in Flow Syntax above. Specifying actions= is optional, but
omitting actions is interpreted as a drop, so the packet will not be sent
anywhere from the switch. actions must be specified at the end of
each line, like for flow mods.
Some ovs-ofctl commands accept an argument that describes a
group or groups. Such flow descriptions comprise a series
field=value assignments, separated by commas or white
space. (Embedding spaces into a group description normally requires quoting
to prevent the shell from breaking the description into multiple
arguments.). Unless noted otherwise only the last instance of each field is
honoured.
- group_id=id
- The integer group id of group. When this field is specified in
del-groups or dump-groups, the keyword "all" may
be used to designate all groups. This field is required.
- type=type
- The type of the group. The add-group, add-groups and
mod-groups commands require this field. It is prohibited for other
commands. The following keywords designated the allowed types:
- all
- Execute all buckets in the group.
- select
- Execute one bucket in the group, balancing across the buckets according to
their weights. To select a bucket, for each live bucket, Open vSwitch
hashes flow data with the bucket ID and multiplies by the bucket weight to
obtain a ``score,'' and then selects the bucket with the highest score.
Use selection_method to control the flow data used for
selection.
- indirect
- Executes the one bucket in the group.
- ff
-
- fast_failover
- Executes the first live bucket in the group which is associated with a
live port or group.
- command_bucket_id=id
- The bucket to operate on. The insert-buckets and
remove-buckets commands require this field. It is prohibited for
other commands. id may be an integer or one of the following
keywords:
- all
- Operate on all buckets in the group. Only valid when used with the
remove-buckets command in which case the effect is to remove all
buckets from the group.
- first
- Operate on the first bucket present in the group. In the case of the
insert-buckets command the effect is to insert new bucets just
before the first bucket already present in the group; or to replace the
buckets of the group if there are no buckets already present in the group.
In the case of the remove-buckets command the effect is to remove
the first bucket of the group; or do nothing if there are no buckets
present in the group.
- last
- Operate on the last bucket present in the group. In the case of the
insert-buckets command the effect is to insert new bucets just
after the last bucket already present in the group; or to replace the
buckets of the group if there are no buckets already present in the group.
In the case of the remove-buckets command the effect is to remove
the last bucket of the group; or do nothing if there are no buckets
present in the group.
- If id is an integer then it should correspond to the
bucket_id of a bucket present in the group. In case of the
insert-buckets command the effect is to insert buckets just before
the bucket in the group whose bucket_id is id. In case of
the iremove-buckets command the effect is to remove the in the
group whose bucket_id is id. It is an error if there is no
bucket persent group in whose bucket_id is id.
- selection_method=method
- The selection method used to select a bucket for a select group. This is a
string of 1 to 15 bytes in length known to lower layers. This field is
optional for add-group, add-groups and mod-group
commands on groups of type select. Prohibited otherwise. If no
selection method is specified, Open vSwitch up to release 2.9 applies the
hash method with default fields. From 2.10 onwards Open vSwitch
defaults to the dp_hash method with symmetric L3/L4 hash algorithm,
unless the weighted group buckets cannot be mapped to a maximum of 64
dp_hash values with sufficient accuracy. In those rare cases Open vSwitch
2.10 and later fall back to the hash method with the default set of
hash fields.
- dp_hash
- Use a datapath computed hash value. The hash algorithm varies accross
different datapath implementations. dp_hash uses the upper 32 bits
of the selection_method_param as the datapath hash algorithm
selector. The supported values are 0 (corresponding to hash
computation over the IP 5-tuple) and 1 (corresponding to a
symmetric hash computation over the IP 5-tuple). Selecting specific
fields with the fields option is not supported with
dp_hash). The lower 32 bits are used as the hash basis.
- Using dp_hash has the advantage that it does not require the
generated datapath flows to exact match any additional packet header
fields. For example, even if multiple TCP connections thus hashed to
different select group buckets have different source port numbers,
generally all of them would be handled with a small set of already
established datapath flows, resulting in less latency for TCP SYN packets.
The downside is that the shared datapath flows must match each packet
twice, as the datapath hash value calculation happens only when needed,
and a second match is required to match some bits of its value. This
double-matching incurs a small additional latency cost for each packet,
but this latency is orders of magnitude less than the latency of creating
new datapath flows for new TCP connections.
- hash
- Use a hash computed over the fields specified with the fields
option, see below. If no hash fields are specified, hash defaults
to a symmetric hash over the combination of MAC addresses, VLAN tags,
Ether type, IP addresses and L4 port numbers. hash uses the
selection_method_param as the hash basis.
- Note that the hashed fields become exact matched by the datapath flows.
For example, if the TCP source port is hashed, the created datapath flows
will match the specific TCP source port value present in the packet
received. Since each TCP connection generally has a different source port
value, a separate datapath flow will be need to be inserted for each TCP
connection thus hashed to a select group bucket.
- This option uses a Netronome OpenFlow extension which is only supported
when using Open vSwitch 2.4 and later with OpenFlow 1.5 and later.
- selection_method_param=param
- 64-bit integer parameter to the selection method selected by the
selection_method field. The parameter's use is defined by the
lower-layer that implements the selection_method. It is optional if
the selection_method field is specified as a non-empty string.
Prohibited otherwise. The default value is zero.
- This option uses a Netronome OpenFlow extension which is only supported
when using Open vSwitch 2.4 and later with OpenFlow 1.5 and later.
- fields=field
-
- fields(field[=mask]...)
- The field parameters to selection method selected by the
selection_method field. The syntax is described in Flow
Syntax with the additional restrictions that if a value is provided
it is treated as a wildcard mask and wildcard masks following a slash are
prohibited. The pre-requisites of fields must be provided by any flows
that output to the group. The use of the fields is defined by the
lower-layer that implements the selection_method. They are optional
if the selection_method field is specified as ``hash', prohibited
otherwise. The default is no fields.
- This option will use a Netronome OpenFlow extension which is only
supported when using Open vSwitch 2.4 and later with OpenFlow 1.5 and
later.
- bucket=bucket_parameters
- The add-group, add-groups and mod-group commands
require at least one bucket field. Bucket fields must appear after all
other fields. Multiple bucket fields to specify multiple buckets. The
order in which buckets are specified corresponds to their order in the
group. If the type of the group is "indirect" then only one
group may be specified. bucket_parameters consists of a list of
field=value assignments, separated by commas or white
space followed by a comma-separated list of actions. The fields for
bucket_parameters are:
- bucket_id=id
- The 32-bit integer group id of the bucket. Values greater than 0xffffff00
are reserved. This field was added in Open vSwitch 2.4 to conform with the
OpenFlow 1.5 specification. It is not supported when earlier versions of
OpenFlow are used. Open vSwitch will automatically allocate bucket ids
when they are not specified.
- actions=[action][,action...]
- The syntax of actions are identical to the actions= field described
in Flow Syntax above. Specifying actions= is optional, any
unknown bucket parameter will be interpreted as an action.
- weight=value
- The relative weight of the bucket as an integer. This may be used by the
switch during bucket select for groups whose type is
select.
- watch_port=port
- Port used to determine liveness of group. This or the watch_group
field is required for groups whose type is ff or
fast_failover. This or the watch_group field can also be
used for groups whose type is select.
- watch_group=group_id
- Group identifier of group used to determine liveness of group. This or the
watch_port field is required for groups whose type is
ff or fast_failover. This or the watch_port field can
also be used for groups whose type is select.
The meter table commands accept an argument that describes a
meter. Such meter descriptions comprise a series
field=value assignments, separated by commas or white
space. (Embedding spaces into a group description normally requires quoting
to prevent the shell from breaking the description into multiple
arguments.). Unless noted otherwise only the last instance of each field is
honoured.
- meter=id
- The identifier for the meter. An integer is used to specify a user-defined
meter. In addition, the keywords "all", "controller",
and "slowpath", are also supported as virtual meters. The
"controller" and "slowpath" virtual meters apply to
packets sent to the controller and to the OVS userspace,
respectively.
- When this field is specified in del-meter, dump-meter, or
meter-stats, the keyword "all" may be used to designate
all meters. This field is required, except for meter-stats, which
dumps all stats when this field is not specified.
- kbps
-
- pktps
- The unit for the rate and burst_size band parameters.
kbps specifies kilobits per second, and pktps specifies
packets per second. A unit is required for the add-meter and
mod-meter commands.
- burst
- If set, enables burst support for meter bands through the
burst_size parameter.
- stats
- If set, enables the collection of meter and band statistics.
- bands=band_parameters
- The add-meter and mod-meter commands require at least one
band specification. Bands must appear after all other fields.
- type=type
- The type of the meter band. This keyword starts a new band specification.
Each band specifies a rate above which the band is to take some action.
The action depends on the band type. If multiple bands' rate is exceeded,
then the band with the highest rate among the exceeded bands is selected.
The following keywords designate the allowed meter band types:
- drop
- Drop packets exceeding the band's rate limit.
- The other band_parameters
are:
- rate=value
- The relative rate limit for this band, in kilobits per second or packets
per second, depending on whether kbps or pktps was
specified.
- burst_size=size
- If burst is specified for the meter entry, configures the maximum
burst allowed for the band in kilobits or packets, depending on whether
kbps or pktps was specified. If unspecified, the switch is
free to select some reasonable value depending on its configuration.