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

NAME
ovs-dpctl - administer Open vSwitch datapaths

SYNOPSIS
ovs-dpctl [options] command [switch] [args...]

DESCRIPTION
The ovs-dpctl program can create, modify, and delete Open vSwitch data‐
paths. A single machine may host any number of datapaths.

This program works only with datapaths that are implemented outside of
ovs-vswitchd itself, such as the Linux and Windows kernel-based data‐
paths. To manage datapaths that are integrated into ovs-vswitchd, such
as the userspace (netdev) datapath, use ovs-appctl(8) to invoke the
dpctl/* commands, which are documented in ovs-vswitchd(8).

A newly created datapath is associated with only one network device, a
virtual network device sometimes called the datapath's ``local port''.
A newly created datapath is not, however, associated with any of the
host's other network devices. To intercept and process traffic on a
given network device, use the add-if command to explicitly add that
network device to the datapath.

If ovs-vswitchd(8) is in use, use ovs-vsctl(8) instead of ovs-dpctl.

Most ovs-dpctl commands that work with datapaths take an argument that
specifies the name of the datapath. Datapath names take the form
[type@]name, where name is the network device associated with the data‐
path's local port. If type is given, it specifies the datapath
provider of name, otherwise the default provider system is assumed.

The following commands manage datapaths. Do not use commands to add or
remove or modify datapaths if ovs-vswitchd is running because this in‐
terferes with ovs-vswitchd's own datapath management.

add-dp dp [netdev[,option]...]
Creates datapath dp, with a local port also named dp. This will
fail if a network device dp already exists.

If netdevs are specified, ovs-dpctl adds them to the new data‐
path, just as if add-if was specified.

del-dp dp
Deletes datapath dp. If dp is associated with any network de‐
vices, they are automatically removed.

add-if dp netdev[,option]...
Adds each netdev to the set of network devices datapath dp moni‐
tors, where dp is the name of an existing datapath, and netdev
is the name of one of the host's network devices, e.g. eth0.
Once a network device has been added to a datapath, the datapath
has complete ownership of the network device's traffic and the
network device appears silent to the rest of the system.

A netdev may be followed by a comma-separated list of options.
The following options are currently supported:

type=type
Specifies the type of port to add. The default type is
system.

port_no=port
Requests a specific port number within the datapath. If
this option is not specified then one will be automati‐
cally assigned.

key=value
Adds an arbitrary key-value option to the port's configu‐
ration.

ovs-vswitchd.conf.db(5) documents the available port types and
options.

set-if dp port[,option]...
Reconfigures each port in dp as specified. An option of the
form key=value adds the specified key-value option to the port
or overrides an existing key's value. An option of the form
key=, that is, without a value, deletes the key-value named key.
The type and port number of a port cannot be changed, so type
and port_no are only allowed if they match the existing configu‐
ration.

del-if dp netdev...
Removes each netdev from the list of network devices datapath dp
monitors.

dump-dps
Prints the name of each configured datapath on a separate line.

[-s | --statistics] show [dp...]
Prints a summary of configured datapaths, including their data‐
path numbers and a list of ports connected to each datapath.
(The local port is identified as port 0.) If -s or --statistics
is specified, then packet and byte counters are also printed for
each port.

The datapath numbers consists of flow stats and mega flow mask
stats.

The "lookups" row displays three stats related to flow lookup
triggered by processing incoming packets in the datapath. "hit"
displays number of packets matches existing flows. "missed" dis‐
plays the number of packets not matching any existing flow and
require user space processing. "lost" displays number of pack‐
ets destined for user space process but subsequently dropped be‐
fore reaching userspace. The sum of "hit" and "miss" equals to
the total number of packets datapath processed.

The "flows" row displays the number of flows in datapath.

The "masks" row displays the mega flow mask stats. This row is
omitted for datapath not implementing mega flow. "hit" displays
the total number of masks visited for matching incoming packets.
"total" displays number of masks in the datapath. "hit/pkt" dis‐
plays the average number of masks visited per packet; the ratio
between "hit" and total number of packets processed by the data‐
path.

If one or more datapaths are specified, information on only
those datapaths are displayed. Otherwise, ovs-dpctl displays
information about all configured datapaths.

DATAPATH FLOW TABLE DEBUGGING COMMANDS
The following commands are primarily useful for debugging Open vSwitch.
The flow table entries (both matches and actions) that they work with
are not OpenFlow flow entries. Instead, they are different and consid‐
erably simpler flows maintained by the Open vSwitch kernel module. Do
not use commands to add or remove or modify datapath flows if
ovs-vswitchd is running because it interferes with ovs-vswitchd's own
datapath flow management. Use ovs-ofctl(8), instead, to work with
OpenFlow flow entries.

The dp argument to each of these commands is optional when exactly one
datapath exists, in which case that datapath is the default. When mul‐
tiple datapaths exist, then a datapath name is required.

[-m | --more] [--names | --no-names] dump-flows [dp] [filter=filter]
[type=type] [pmd=pmd]
Prints to the console all flow entries in datapath dp's flow ta‐
ble. Without -m or --more, output omits match fields that a
flow wildcards entirely; with -m or --more, output includes all
wildcarded fields.

If filter=filter is specified, only displays the flows that
match the filter. filter is a flow in the form similar to that
accepted by ovs-ofctl(8)'s add-flow command. (This is not an
OpenFlow flow: besides other differences, it never contains
wildcards.) The filter is also useful to match wildcarded
fields in the datapath flow. As an example, fil‐
ter='tcp,tp_src=100' will match the datapath flow containing
'tcp(src=80/0xff00,dst=8080/0xff)'.

If pmd=pmd is specified, only displays flows of the specified
pmd. Using pmd=-1 will restrict the dump to flows from the main
thread. This option is only supported by the userspace data‐
path.

If type=type is specified, only displays flows of the specified
types. This option supported only for ovs-appctl
dpctl/dump-flows. type is a comma separated list, which can
contain any of the following:
ovs - displays flows handled in the ovs dp
tc - displays flows handled in the tc dp
dpdk - displays flows fully offloaded by dpdk
offloaded - displays flows offloaded to the HW
non-offloaded - displays flows not offloaded to the HW
partially-offloaded - displays flows where only part of their
proccessing is done in HW
all - displays all the types of flows

By default all the types of flows are displayed. ovs-dpctl al‐
ways acts as if the type was ovs.

add-flow [dp] flow actions

[--clear] [--may-create] [-s | --statistics] mod-flow [dp] flow actions
Adds or modifies a flow in dp's flow table that, when a packet
matching flow arrives, causes actions to be executed.

The add-flow command succeeds only if flow does not already ex‐
ist in dp. Contrariwise, mod-flow without --may-create only
modifies the actions for an existing flow. With --may-create,
mod-flow will add a new flow or modify an existing one.

If -s or --statistics is specified, then mod-flow prints the
modified flow's statistics. A flow's statistics are the number
of packets and bytes that have passed through the flow, the
elapsed time since the flow last processed a packet (if ever),
and (for TCP flows) the union of the TCP flags processed through
the flow.

With --clear, mod-flow zeros out the flow's statistics. The
statistics printed if -s or --statistics is also specified are
those from just before clearing the statistics.

NOTE: flow and actions do not match the syntax used with
ovs-ofctl(8)'s add-flow command.

Usage Examples

Forward ARP between ports 1 and 2 on datapath myDP:

ovs-dpctl add-flow myDP \
"in_port(1),eth(),eth_type(0x0806),arp()" 2

ovs-dpctl add-flow myDP \
"in_port(2),eth(),eth_type(0x0806),arp()" 1

Forward all IPv4 traffic between two addresses on ports 1 and 2:

ovs-dpctl add-flow myDP \
"in_port(1),eth(),eth_type(0x800),\
ipv4(src=172.31.110.4,dst=172.31.110.5)" 2

ovs-dpctl add-flow myDP \
"in_port(2),eth(),eth_type(0x800),\
ipv4(src=172.31.110.5,dst=172.31.110.4)" 1

add-flows [dp] file
mod-flows [dp] file
del-flows [dp] file
Reads flow entries from file (or stdin if file is -) and adds,
modifies, or deletes each entry to the datapath. Each flow
specification (e.g., each line in file) may start with add, mod‐
ify, or delete keyword to specify whether a flow is to be added,
modified, or deleted. A flow specification without one of these
keywords is treated based on the used command. All flow modifi‐
cations are executed as individual transactions in the order
specified.

[-s | --statistics] del-flow [dp] flow
Deletes the flow from dp's flow table that matches flow. If -s
or --statistics is specified, then del-flow prints the deleted
flow's statistics.

[-m | --more] [--names | --no-names] get-flow [dp] ufid:ufid
Fetches the flow from dp's flow table with unique identifier
ufid. ufid must be specified as a string of 32 hexadecimal
characters.

del-flows [dp]
Deletes all flow entries from datapath dp's flow table.

DATAPATH FLOW CACHE COMMANDS
The following commands are useful for debugging and configuring the
datapath flow cache settings.

cache-get-size [dp]
Prints the current cache sizes to the console.

cache-set-size dp cache size
Set the dp's specific cache to the given size. The cache name
can be found by using the cache-get-size command.

CONNECTION TRACKING TABLE COMMANDS
The following commands are useful for debugging and configuring the
connection tracking table in the datapath.

N.B.(Linux specific): the system datapaths (i.e. the Linux kernel mod‐
ule Open vSwitch datapaths) share a single connection tracking table
(which is also used by other kernel subsystems, such as iptables, nfta‐
bles and the regular host stack). Therefore, the following commands do
not apply specifically to one datapath.

ipf-set-enabled [dp] v4|v6
ipf-set-disabled [dp] v4|v6
Enables or disables IP fragmentation handling for the userspace
connection tracker. Either v4 or v6 must be specified. Both
IPv4 and IPv6 fragment reassembly are enabled by default. Only
supported for the userspace datapath.

ipf-set-min-frag [dp] v4|v6 minfrag
Sets the minimum fragment size (L3 header and data) for non-fi‐
nal fragments to minfrag. Either v4 or v6 must be specified.
For enhanced DOS security, higher minimum fragment sizes can
usually be used. The default IPv4 value is 1200 and the clamped
minimum is 400. The default IPv6 value is 1280, with a clamped
minimum of 400, for testing flexibility. The maximum fragment
size is not clamped, however, setting this value too high might
result in valid fragments being dropped. Only supported for
userspace datapath.

ipf-set-max-nfrags [dp] maxfrags
Sets the maximum number of fragments tracked by the userspace
datapath connection tracker to maxfrags. The default value is
1000 and the clamped maximum is 5000. Note that packet buffers
can be held by the fragmentation module while fragments are in‐
complete, but will timeout after 15 seconds. Memory pool sizing
should be set accordingly when fragmentation is enabled. Only
supported for userspace datapath.

[-m | --more] ipf-get-status [dp]
Gets the configuration settings and fragment counters associated
with the fragmentation handling of the userspace datapath con‐
nection tracker. With -m or --more, also dumps the IP fragment
lists. Only supported for userspace datapath.

[-m | --more] [-s | --statistics] dump-conntrack [dp] [zone=zone]
Prints to the console all the connection entries in the tracker
used by dp. If zone=zone is specified, only shows the connec‐
tions in zone. With --more, some implementation specific de‐
tails are included. With --statistics timeouts and timestamps
are added to the output.

flush-conntrack [dp] [zone=zone] [ct-tuple]
Flushes the connection entries in the tracker used by dp based
on zone and connection tracking tuple ct-tuple. If ct-tuple is
not provided, flushes all the connection entries. If zone=zone
is specified, only flushes the connections in zone.

If ct-tuple is provided, flushes the connection entry specified
by ct-tuple in zone. The zone defaults to 0 if it is not pro‐
vided. The userspace connection tracker requires flushing with
the original pre-NATed tuple and a warning log will be otherwise
generated. An example of an IPv4 ICMP ct-tuple:

"ct_nw_src=10.1.1.1,ct_nw_dst=10.1.1.2,ct_nw_proto=1,icmp_type=8,icmp_code=0,icmp_id=10"

An example of an IPv6 TCP ct-tuple:

"ct_ipv6_src=fc00::1,ct_ipv6_dst=fc00::2,ct_nw_proto=6,ct_tp_src=1,ct_tp_dst=2"

[-m | --more] ct-stats-show [dp] [zone=zone]
Displays the number of connections grouped by protocol used by
dp. If zone=zone is specified, numbers refer to the connections
in zone. With --more, groups by connection state for each pro‐
tocol.

ct-bkts [dp] [gt=threshold]
For each conntrack bucket, displays the number of connections
used by dp. If gt=threshold is specified, bucket numbers are
displayed when the number of connections in a bucket is greater
than threshold.

ct-set-maxconns [dp] maxconns
Sets the maximum limit of connection tracker entries to maxconns
on dp. This can be used to reduce the processing load on the
system due to connection tracking or simply limiting connection
tracking. If the number of connections is already over the new
maximum limit request then the new maximum limit will be en‐
forced when the number of connections decreases to that limit,
which normally happens due to connection expiry. Only supported
for userspace datapath.

ct-get-maxconns [dp]
Prints the maximum limit of connection tracker entries on dp.
Only supported for userspace datapath.

ct-get-nconns [dp]
Prints the current number of connection tracker entries on dp.
Only supported for userspace datapath.

ct-enable-tcp-seq-chk [dp]
ct-disable-tcp-seq-chk [dp]
Enables or disables TCP sequence checking. When set to dis‐
abled, all sequence number verification is disabled, including
for TCP resets. This is similar, but not the same as 'be_lib‐
eral' mode, as in Netfilter. Disabling sequence number verifi‐
cation is not an optimization in itself, but is needed for some
hardware offload support which might offer some performance ad‐
vantage. Sequence number checking is enabled by default to en‐
force better security and should only be disabled if required
for hardware offload support. This command is only supported
for the userspace datapath.

ct-get-tcp-seq-chk [dp]
Prints whether TCP sequence checking is enabled or disabled on
dp. Only supported for the userspace datapath.

ct-set-limits [dp] [default=default_limit] [zone=zone,limit=limit]...
Sets the maximum allowed number of connections in a connection
tracking zone. A specific zone may be set to limit, and multi‐
ple zones may be specified with a comma-separated list. If a
per-zone limit for a particular zone is not specified in the
datapath, it defaults to the default per-zone limit. A default
zone may be specified with the default=default_limit argument.
Initially, the default per-zone limit is unlimited. An unlim‐
ited number of entries may be set with 0 limit.

ct-del-limits [dp] zone=zone[,zone]...
Deletes the connection tracking limit for zone. Multiple zones
may be specified with a comma-separated list.

ct-get-limits [dp] [zone=zone[,zone]...]
Retrieves the maximum allowed number of connections and current
counts per-zone. If zone is given, only the specified zone(s)
are printed. If no zones are specified, all the zone limits and
counts are provided. The command always displays the default
zone limit.

OPTIONS
-t
--timeout=secs
Limits ovs-dpctl runtime to approximately secs seconds. If the
timeout expires, ovs-dpctl will exit with a SIGALRM signal.

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

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

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

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

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

Case is not significant within spec.

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

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

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

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

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

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

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

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

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

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

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

• null, discards all messages logged to syslog.

The default is taken from the OVS_SYSLOG_METHOD environment
variable; if it is unset, the default is libc.

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

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