The ovs-dpctl program can create, modify, and delete Open
vSwitch datapaths. 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 datapaths. 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 datapath'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 interferes 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
datapath, just as if add-if was specified.
- del-dp dp
- Deletes datapath dp. If dp is associated with any network
devices, they are automatically removed.
- add-if dp
netdev[,option]...
- Adds each netdev to the set of network devices datapath dp
monitors, 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 automatically assigned.
- key=value
- Adds an arbitrary key-value option to the port's configuration.
- 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 configuration.
- 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 datapath 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"
displays the number of packets not matching any existing flow and require
user space processing. "lost" displays number of packets
destined for user space process but subsequently dropped before 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" displays the average number of masks visited per
packet; the ratio between "hit" and total number of packets
processed by the datapath.
- If one or more datapaths are specified, information on only those
datapaths are displayed. Otherwise, ovs-dpctl displays information
about all configured datapaths.
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
considerably 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 multiple 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 table.
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 similiar 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, filter='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
datapath.
- 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 always
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
exist 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, modify, 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
modifications 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.
The following commands are useful for debugging and configuring
the connection tracking table in the datapath.
The dp argument to each of these commands is optional when
exactly one datapath exists, in which case that datapath is the default.
When multiple datapaths exist, then a datapath name is required.
N.B.(Linux specific): the system datapaths (i.e. the
Linux kernel module Open vSwitch datapaths) share a single connection
tracking table (which is also used by other kernel subsystems, such as
iptables, nftables 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-final
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 incomplete, 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 connection 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
connections in zone. With --more, some implementation
specific details 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
provided. 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
protocol.
- 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 enforced 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 disabled, all
sequence number verification is disabled, including for TCP resets. This
is similar, but not the same as 'be_liberal' mode, as in Netfilter.
Disabling sequence number verification is not an optimization in itself,
but is needed for some hardware offload support which might offer some
performance advantage. Sequence number checking is enabled by default to
enforce 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 multiple
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 unlimited 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.