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Man Pages


Manual Reference Pages  -  OVS-OFCTL (8)

NAME

ovs-ofctl - administer OpenFlow switches

CONTENTS

Synopsis
Description
Options
Examples

SYNOPSIS

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

DESCRIPTION

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

    OpenFlow Switch Management Commands

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

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

ssl:ip[:port]
tcp:ip[:port] The specified port on the host at the given ip, which must be expressed as an IP address (not a DNS name) in IPv4 or IPv6 address format. Wrap IPv6 addresses in square brackets, e.g. tcp:[::1]:6633. For ssl, the --private-key, --certificate, and --ca-cert options are mandatory.
If port is not specified, it currently defaults to 6633. In the future, the default will change to 6653, which is the IANA-defined value.
unix:file
  On POSIX, a Unix domain server socket named file.
On Windows, a localhost TCP port written in file.
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-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 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 ifconfig up or ifconfig down on a Unix system.
stp
no-stp Enable or disable 802.1D spanning tree protocol (STP) on the interface. OpenFlow implementations that don’t support STP will refuse to enable it.
receive
no-receive
receive-stp
no-receive-stp Enable or disable OpenFlow processing of packets received on this interface. When packet processing is disabled, packets will be dropped instead of being processed through the OpenFlow table. The receive or no-receive setting applies to all packets except 802.1D spanning tree packets, which are separately controlled by receive-stp or no-receive-stp.
forward
no-forward Allow or disallow forwarding of traffic to this interface. By default, forwarding is enabled.
flood
no-flood Controls whether an OpenFlow flood action will send traffic out this interface. By default, flooding is enabled. Disabling flooding is primarily useful to prevent loops when a spanning tree protocol is not in use.
packet-in
no-packet-in Controls whether packets received on this interface that do not match a flow table entry generate a ‘‘packet in’’ message to the OpenFlow controller. By default, ‘‘packet in’’ messages are enabled.
The show command displays (among other information) the configuration that mod-port changes.
get-frags switch Prints switch’s fragment handling mode. See set-frags, below, for a description of each fragment handling mode.
The show command also prints the fragment handling mode among its other output.
set-frags switch frag_mode Configures switch’s treatment of IPv4 and IPv6 fragments. The choices for frag_mode are:
normal Fragments pass through the flow table like non-fragmented packets. The TCP ports, UDP ports, and ICMP type and code fields are always set to 0, even for fragments where that information would otherwise be available (fragments with offset 0). This is the default fragment handling mode for an OpenFlow switch.
drop Fragments are dropped without passing through the flow table.
reassemble The switch reassembles fragments into full IP packets before passing them through the flow table. Open vSwitch does not implement this fragment handling mode.
nx-match Fragments pass through the flow table like non-fragmented packets. The TCP ports, UDP ports, and ICMP type and code fields are available for matching for fragments with offset 0, and set to 0 in fragments with nonzero offset. This mode is a Nicira extension.
See the description of ip_frag, below, for a way to match on whether a packet is a fragment and on its fragment offset.
dump-flows switch [flows]
  Prints to the console all flow entries in switch’s tables that match flows. If flows is omitted, all flows in the switch are retrieved. See Flow Syntax, below, for the syntax of flows. The output format is described in Table Entry Output.
By default, ovs-ofctl prints flow entries in the same order that the switch sends them, which is unlikely to be intuitive or consistent. See the description of --sort and --rsort, under OPTIONS below, to influence the display order.
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.

    OpenFlow 1.1+ Group Table Commands

The following commands work only with switches that support OpenFlow 1.1 or later. Because support for OpenFlow 1.1 and later is still experimental in Open vSwitch, it is necessary to explicitly enable these protocol versions in ovs-ofctl (using -O) and in the switch itself (with the protocols column in the Bridge table). For more information, see ‘‘Q: What versions of OpenFlow does Open vSwitch support?’’ in the Open vSwitch FAQ.
dump-groups switch [group] Prints group entries in switch’s tables to console. To dump only a specific group, specify its number as group. Otherwise, if group is omitted, or if it is specified as ALL, then all groups are printed. Each line of output is a group entry as described in Group Syntax below.
Only OpenFlow 1.5 and later support dumping a specific group. Earlier versions of OpenFlow always dump all groups.
dump-group-features switch Prints to the console the group features of the switch.
dump-group-stats switch [groups] Prints to the console statistics for the specified groups in the switch’s tables. If groups is omitted then statistics for all groups are printed. See Group Syntax, below, for the syntax of groups.
mod-table switch table_id flow_miss_handling An OpenFlow 1.0 switch looks up each packet that arrives at the switch in table 0, then in table 1 if there is no match in table 0, then in table 2, and so on until the packet finds a match in some table. Finally, if no match was found, the switch sends the packet to the controller
OpenFlow 1.1 and later offer more flexibility. This command configures the flow table miss handling configuration for table table_id in switch. table_id may be an OpenFlow table number between 0 and 254, inclusive, or the keyword ALL to modify all tables. flow_miss_handling may be any one of the following:
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.)

    OpenFlow 1.3+ Switch Meter Table Commands

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

OpenFlow 1.3 introduced support for meters, so these commands only work with switches that support OpenFlow 1.3 or later. The caveats described for groups in the previous section also apply to meters.
add-meter switch meter Add a meter entry to switch’s tables. The meter syntax is described in section Meter Syntax, below.
mod-meter switch meter Modify an existing meter.
del-meters switch
del-meter switch [meter] Delete entries from switch’s meter table. meter can specify a single meter with syntax meter=id, or all meters with syntax meter=all.
dump-meters switch
dump-meter switch [meter] Print meter configuration. meter can specify a single meter with syntax meter=id, or all meters with syntax meter=all.
meter-stats switch [meter] Print meter statistics. meter can specify a single meter with syntax meter=id, or all meters with syntax meter=all.
meter-features switch Print meter features.

    OpenFlow Switch Flow Table Commands

These commands manage the flow table in an OpenFlow switch. In each case, flow specifies a flow entry in the format described in Flow Syntax, below, and file is a text file that contains zero or more flows in the same syntax, one per line.
add-flow switch flow
add-flow switch - < file
add-flows switch file Add each flow entry to switch’s tables.
[--strict] mod-flows switch flow
[--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.
del-flows switch
[--strict] del-flows switch [flow]
[--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.
[--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. This resets all the flow packet and byte counters to 0, which can be useful for debugging.
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 in_port actions packet... Connects to switch and instructs it to execute the OpenFlow actions on each packet. For the purpose of executing the actions, the packets are considered to have arrived on in_port, which may be an OpenFlow port number or name (e.g. eth0), the keyword LOCAL (the preferred way to refer to the OpenFlow ‘‘local’’ port), or the keyword NONE to indicate that the packet was generated by the switch itself.

    OpenFlow Switch Group Table Commands

These commands manage the group table in an OpenFlow switch. In each case, group specifies a group entry in the format described in Group Syntax, below, and file is a text file that contains zero or more groups in the same syntax, one per line.

add-group switch group
add-group switch - < file
add-groups switch file Add each group entry to switch’s tables.
mod-group switch group
mod-group switch - < file Modify the action buckets in entries from switch’s tables for each group entry.
del-groups switch
del-groups switch [group]
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.

    OpenFlow Switch Monitoring Commands

snoop switch Connects to switch and prints to the console all OpenFlow messages received. Unlike other ovs-ofctl commands, if switch is the name of a bridge, then the snoop command connects to a Unix domain socket named /var/run/openvswitch/bridge.snoop. ovs-vswitchd listens on such a socket for each bridge and sends to it all of the OpenFlow messages sent to or received from its configured OpenFlow controller. Thus, this command can be used to view OpenFlow protocol activity between a switch and its controller.
When a switch has more than one controller configured, only the traffic to and from a single controller is output. If none of the controllers is configured as a master or a slave (using a Nicira extension to OpenFlow 1.0 or 1.1, or a standard request in OpenFlow 1.2 or later), then a controller is chosen arbitrarily among them. If there is a master controller, it is chosen; otherwise, if there are any controllers that are not masters or slaves, one is chosen arbitrarily; otherwise, a slave controller is chosen arbitrarily. This choice is made once at connection time and does not change as controllers reconfigure their roles.
If a switch has no controller configured, or if the configured controller is disconnected, no traffic is sent, so monitoring will not show any traffic.
monitor switch [miss-len] [invalid_ttl] [watch:[spec...]] Connects to switch and prints to the console all OpenFlow messages received. Usually, switch should specify the name of a bridge in the ovs-vswitchd database.
If miss-len is provided, ovs-ofctl sends an OpenFlow ‘‘set configuration’’ message at connection setup time that requests miss-len bytes of each packet that misses the flow table. Open vSwitch does not send these and other asynchronous messages to an ovs-ofctl monitor client connection unless a nonzero value is specified on this argument. (Thus, if miss-len is not specified, very little traffic will ordinarily be printed.)
If invalid_ttl is passed, ovs-ofctl sends an OpenFlow ‘‘set configuration’’ message at connection setup time that requests INVALID_TTL_TO_CONTROLLER, so that ovs-ofctl monitor can receive ‘‘packet-in’’ messages when TTL reaches zero on dec_ttl action.
watch:[spec...] causes ovs-ofctl to send a ‘‘monitor request’’ Nicira extension message to the switch at connection setup time. This message causes the switch to send information about flow table changes as they occur. The following comma-separated spec syntax is available:
!initial Do not report the switch’s initial flow table contents.
!add Do not report newly added flows.
!delete Do not report deleted flows.
!modify Do not report modifications to existing flows.
!own Abbreviate changes made to the flow table by ovs-ofctl’s own connection to the switch. (These could only occur using the ofctl/send command described below under RUNTIME MANAGEMENT COMMANDS.)
!actions Do not report actions as part of flow updates.
table=number Limits the monitoring to the table with the given number between 0 and 254. By default, all tables are monitored.
out_port=port If set, only flows that output to port are monitored. The port may be an OpenFlow port number or keyword (e.g. LOCAL).
field=value Monitors only flows that have field specified as the given value. Any syntax valid for matching on dump-flows may be used.
This command may be useful for debugging switch or controller implementations. With watch:, it is particularly useful for observing how a controller updates flow tables.

    OpenFlow Switch and Controller Commands

The following commands, like those in the previous section, may be applied to OpenFlow switches, using any of the connection methods described in that section. Unlike those commands, these may also be applied to OpenFlow controllers.
probe target
  Sends a single OpenFlow echo-request message to target and waits for the response. With the -t or --timeout option, this command can test whether an OpenFlow switch or controller is up and running.
ping target [n]
  Sends a series of 10 echo request packets to target and times each reply. The echo request packets consist of an OpenFlow header plus n bytes (default: 64) of randomly generated payload. This measures the latency of individual requests.
benchmark target n count
  Sends count echo request packets that each consist of an OpenFlow header plus n bytes of payload and waits for each response. Reports the total time required. This is a measure of the maximum bandwidth to target for round-trips of n-byte messages.

    Other Commands

ofp-parse file Reads file (or stdin if file is -) as a series of OpenFlow messages in the binary format used on an OpenFlow connection, and prints them to the console. This can be useful for printing OpenFlow messages captured from a TCP stream.
ofp-parse-pcap file [port...] Reads file, which must be in the PCAP format used by network capture tools such as tcpdump or wireshark, extracts all the TCP streams for OpenFlow connections, and prints the OpenFlow messages in those connections in human-readable format on stdout.
OpenFlow connections are distinguished by TCP port number. Non-OpenFlow packets are ignored. By default, data on TCP ports 6633 and 6653 are considered to be OpenFlow. Specify one or more port arguments to override the default.
This command cannot usefully print SSL encrypted traffic. It does not understand IPv6.

    Flow Syntax

Some ovs-ofctl commands accept an argument that describes a flow or flows. Such flow descriptions comprise a series 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 tp_dst and tp_src, which are L4 fields. ovs-ofctl will warn about flows not in normal form.

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 * may be specified to explicitly mark any of these fields as a wildcard. (* should be quoted to protect it from shell expansion.)
in_port=port Matches OpenFlow port port, which may be an OpenFlow port number or keyword (e.g. LOCAL). ovs-ofctl show.
(The resubmit action can search OpenFlow flow tables with arbitrary in_port values, so flows that match port numbers that do not exist from an OpenFlow perspective can still potentially be matched.)
dl_vlan=vlan Matches IEEE 802.1q Virtual LAN tag vlan. Specify 0xffff as vlan 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.
dl_vlan_pcp=priority Matches IEEE 802.1q Priority Code Point (PCP) priority, which is specified as a value between 0 and 7, inclusive. A higher value indicates a higher frame priority level.
dl_src=xx:xx:xx:xx:xx:xx
dl_dst=xx:xx:xx:xx:xx:xx Matches an Ethernet source (or destination) address specified as 6 pairs of hexadecimal digits delimited by colons (e.g. 00:0A:E4:25:6B:B0).
dl_src=xx:xx:xx:xx:xx:xx/xx:xx:xx:xx:xx:xx
dl_dst=xx:xx:xx:xx:xx:xx/xx:xx:xx:xx:xx:xx Matches an Ethernet destination address specified as 6 pairs of hexadecimal digits delimited by colons (e.g. 00:0A:E4:25:6B:B0), 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:
01:00:00:00:00:00 Match only the multicast bit. Thus, dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 matches all multicast (including broadcast) Ethernet packets, and dl_dst=00:00:00:00:00:00/01:00:00:00:00:00 matches all unicast Ethernet packets.
fe:ff:ff:ff:ff:ff Match all bits except the multicast bit. This is probably not useful.
ff:ff:ff:ff:ff:ff Exact match (equivalent to omitting the mask).
00:00:00:00:00:00 Wildcard all bits (equivalent to dl_dst=*.)
dl_type=ethertype Matches Ethernet protocol type ethertype, which is specified as an integer between 0 and 65535, inclusive, either in decimal or as a hexadecimal number prefixed by 0x (e.g. 0x0806 to match ARP packets).
nw_src=ip[/netmask]
nw_dst=ip[/netmask] When dl_type is 0x0800 (possibly via shorthand, e.g. ip or tcp), matches IPv4 source (or destination) address ip, which may be specified as an IP address or host name (e.g. 192.168.1.1 or www.example.com). The optional netmask allows restricting a match to an IPv4 address prefix. The netmask may be specified as a dotted quad (e.g. 192.168.1.0/255.255.255.0) or as a CIDR block (e.g. 192.168.1.0/24). 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.
When dl_type=0x0806 or arp is specified, matches the ar_spa or ar_tpa field, respectively, in ARP packets for IPv4 and Ethernet.
When dl_type=0x8035 or rarp is specified, matches the ar_spa or ar_tpa field, respectively, in RARP packets for IPv4 and Ethernet.
When dl_type is wildcarded or set to a value other than 0x0800, 0x0806, or 0x8035, the values of nw_src and nw_dst are ignored (see Flow Syntax above).
nw_proto=proto
ip_proto=proto When ip or dl_type=0x0800 is specified, matches IP protocol type proto, 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).
When ipv6 or dl_type=0x86dd is specified, matches IPv6 header type proto, 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 DESIGN document.
When arp or dl_type=0x0806 is specified, matches the lower 8 bits of the ARP opcode. ARP opcodes greater than 255 are treated as 0.
When rarp or dl_type=0x8035 is specified, matches the lower 8 bits of the ARP opcode. ARP opcodes greater than 255 are treated as 0.
When dl_type is wildcarded or set to a value other than 0x0800, 0x0806, 0x8035 or 0x86dd, the value of nw_proto is ignored (see Flow Syntax above).
nw_tos=tos Matches IP ToS/DSCP or IPv6 traffic class field tos, which is specified as a decimal number between 0 and 255, inclusive. Note that the two lower reserved bits are ignored for matching purposes.
When dl_type is wildcarded or set to a value other than 0x0800 or 0x86dd, the value of nw_tos is ignored (see Flow Syntax above).
ip_dscp=dscp Matches IP ToS/DSCP or IPv6 traffic class field dscp, which is specified as a decimal number between 0 and 63, inclusive.
When dl_type is wildcarded or set to a value other than 0x0800 or 0x86dd, the value of ip_dscp is ignored (see Flow Syntax above).
nw_ecn=ecn
ip_ecn=ecn Matches ecn bits in IP ToS or IPv6 traffic class fields, which is specified as a decimal number between 0 and 3, inclusive.
When dl_type is wildcarded or set to a value other than 0x0800 or 0x86dd, the value of nw_ecn is ignored (see Flow Syntax above).
nw_ttl=ttl Matches IP TTL or IPv6 hop limit value ttl, which is specified as a decimal number between 0 and 255, inclusive.
When dl_type is wildcarded or set to a value other than 0x0800 or 0x86dd, the value of nw_ttl is ignored (see Flow Syntax above).
tp_src=port
tp_dst=port When dl_type and nw_proto specify TCP or UDP or SCTP, tp_src and tp_dst match the UDP or TCP or SCTP source or destination port port, respectively, which is specified as a decimal number between 0 and 65535, inclusive (e.g. 80 to match packets originating from a HTTP server).
When dl_type and nw_proto take other values, the values of these settings are ignored (see Flow Syntax above).
tp_src=port/mask
tp_dst=port/mask Bitwise match on TCP (or UDP or SCTP) source or destination port, respectively. The port and mask are 16-bit numbers written in decimal or in hexadecimal prefixed by 0x. Each 1-bit in mask requires that the corresponding bit in port must match. Each 0-bit in mask causes the corresponding bit to be ignored.
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:
01111101000
11111001111
and then to transform those into a series of bitwise matches that accomplish the same results:
01111101xxx
0111111xxxx
10xxxxxxxxx
110xxxxxxxx
1110xxxxxxx
11110xxxxxx
1111100xxxx
which become the following when written in the syntax required by ovs-ofctl:
tcp,tp_src=0x03e8/0xfff8
tcp,tp_src=0x03f0/0xfff0
tcp,tp_src=0x0400/0xfe00
tcp,tp_src=0x0600/0xff00
tcp,tp_src=0x0700/0xff80
tcp,tp_src=0x0780/0xffc0
tcp,tp_src=0x07c0/0xfff0
Only Open vSwitch 1.6 and later supports bitwise matching on transport ports.
Like the exact-match forms of tp_src and tp_dst described above, the bitwise match forms apply only when dl_type and nw_proto specify TCP or UDP or SCTP.
tcp_flags=flags/mask
tcp_flags=[+flag...][-flag...] Bitwise match on TCP flags. The flags and mask are 16-bit numbers written in decimal or in hexadecimal prefixed by 0x. Each 1-bit in mask requires that the corresponding bit in flags must match. Each 0-bit in mask causes the corresponding bit to be ignored.
Alternatively, the flags can be specified by their symbolic names (listed below), each preceded by either + for a flag that must be set, or - for a flag that must be unset, without any other delimiters between the flags. Flags not mentioned are wildcarded. For example, tcp,tcp_flags=+syn-ack matches TCP SYNs that are not ACKs.
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:
0: fin No more data from sender.
1: syn Synchronize sequence numbers.
2: rst Reset the connection.
3: psh Push function.
4: ack Acknowledgement field significant.
5: urg Urgent pointer field significant.
6: ece ECN Echo.
7: cwr Congestion Windows Reduced.
8: ns Nonce Sum.
9-11: Reserved.
12-15: Not matchable, must be zero.
icmp_type=type
icmp_code=code When dl_type and nw_proto specify ICMP or ICMPv6, type matches the ICMP type and code matches the ICMP code. Each is specified as a decimal number between 0 and 255, inclusive.
When dl_type and nw_proto take other values, the values of these settings are ignored (see Flow Syntax above).
table=number For flow dump commands, limits the flows dumped to those in the table with the given number between 0 and 254. If not specified (or if 255 is specified as number), then flows in all tables are dumped.
For flow table modification commands, behavior varies based on the OpenFlow version used to connect to the switch:
OpenFlow 1.0 OpenFlow 1.0 does not support table for modifying flows. ovs-ofctl will exit with an error if table (other than table=255) is specified for a switch that only supports OpenFlow 1.0.
In OpenFlow 1.0, the switch chooses the table into which to insert a new flow. The Open vSwitch software switch always chooses table 0. Other Open vSwitch datapaths and other OpenFlow implementations may choose different tables.
The OpenFlow 1.0 behavior in Open vSwitch for modifying or removing flows depends on whether --strict is used. Without --strict, the command applies to matching flows in all tables. With --strict, the command will operate on any single matching flow in any table; it will do nothing if there are matches in more than one table. (The distinction between these behaviors only matters if non-OpenFlow 1.0 commands were also used, because OpenFlow 1.0 alone cannot add flows with the same matching criteria to multiple tables.)
OpenFlow 1.0 with table_id extension Open vSwitch implements an OpenFlow extension that allows the controller to specify the table on which to operate. ovs-ofctl automatically enables the extension when table is specified and OpenFlow 1.0 is used. ovs-ofctl automatically detects whether the switch supports the extension. As of this writing, this extension is only known to be implemented by Open vSwitch.
With this extension, ovs-ofctl operates on the requested table when table is specified, and acts as described for OpenFlow 1.0 above when no table is specified (or for table=255).
OpenFlow 1.1 OpenFlow 1.1 requires flow table modification commands to specify a table. When table is not specified (or table=255 is specified), ovs-ofctl defaults to table 0.
OpenFlow 1.2 and later OpenFlow 1.2 and later allow flow deletion commands, but not other flow table modification commands, to operate on all flow tables, with the behavior described above for OpenFlow 1.0.
metadata=value[/mask] Matches value either exactly or with optional mask in the metadata field. value and mask are 64-bit integers, by default in decimal (use a 0x prefix to specify hexadecimal). Arbitrary mask values are allowed: a 1-bit in mask indicates that the corresponding bit in value must match exactly, and a 0-bit wildcards that bit. Matching on metadata was added in Open vSwitch 1.8.
The following shorthand notations are also available:
ip Same as dl_type=0x0800.
icmp Same as dl_type=0x0800,nw_proto=1.
tcp Same as dl_type=0x0800,nw_proto=6.
udp Same as dl_type=0x0800,nw_proto=17.
sctp Same as dl_type=0x0800,nw_proto=132.
arp Same as dl_type=0x0806.
rarp Same as dl_type=0x8035.
The following field assignments require support for the NXM (Nicira Extended Match) extension to OpenFlow. When one of these is specified, ovs-ofctl will automatically attempt to negotiate use of this extension. If the switch does not support NXM, then ovs-ofctl will report a fatal error.
vlan_tci=tci[/mask] Matches modified VLAN TCI tci. If mask is omitted, tci is the exact VLAN TCI to match; if mask is specified, then a 1-bit in mask indicates that the corresponding bit in tci must match exactly, and a 0-bit wildcards that bit. Both tci and mask are 16-bit values that are decimal by default; use a 0x prefix to specify them in hexadecimal.
The value that vlan_tci 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 0x1000) forced to 1.
Examples:
vlan_tci=0 Match only packets without an 802.1Q header.
vlan_tci=0xf123 Match packets tagged with priority 7 in VLAN 0x123.
vlan_tci=0x1123/0x1fff Match packets tagged with VLAN 0x123 (and any priority).
vlan_tci=0x5000/0xf000 Match packets tagged with priority 2 (in any VLAN).
vlan_tci=0/0xfff Match packets with no 802.1Q header or tagged with VLAN 0 (and any priority).
vlan_tci=0x5000/0xe000 Match packets with no 802.1Q header or tagged with priority 2 (in any VLAN).
vlan_tci=0/0xefff Match packets with no 802.1Q header or tagged with VLAN 0 and priority 0.
Some of these matching possibilities can also be achieved with dl_vlan and dl_vlan_pcp.
ip_frag=frag_type When dl_type specifies IP or IPv6, frag_type specifies what kind of IP fragments or non-fragments to match. The following values of frag_type are supported:
no Matches only non-fragmented packets.
yes Matches all fragments.
first Matches only fragments with offset 0.
later Matches only fragments with nonzero offset.
not_later Matches non-fragmented packets and fragments with zero offset.
The ip_frag match type is likely to be most useful in nx-match mode. See the description of the set-frags command, above, for more details.
arp_spa=ip[/netmask]
arp_tpa=ip[/netmask] When dl_type specifies either ARP or RARP, arp_spa and arp_tpa match the source and target IPv4 address, respectively. An address may be specified as an IP address or host name (e.g. 192.168.1.1 or www.example.com). The optional netmask allows restricting a match to an IPv4 address prefix. The netmask may be specified as a dotted quad (e.g. 192.168.1.0/255.255.255.0) or as a CIDR block (e.g. 192.168.1.0/24).
arp_sha=xx:xx:xx:xx:xx:xx
arp_tha=xx:xx:xx:xx:xx:xx When dl_type specifies either ARP or RARP, arp_sha and arp_tha match the source and target hardware address, respectively. An address is specified as 6 pairs of hexadecimal digits delimited by colons (e.g. 00:0A:E4:25:6B:B0).
arp_sha=xx:xx:xx:xx:xx:xx/xx:xx:xx:xx:xx:xx
arp_tha=xx:xx:xx:xx:xx:xx/xx:xx:xx:xx:xx:xx When dl_type specifies either ARP or RARP, arp_sha and arp_tha match the source and target hardware address, respectively. An address is specified as 6 pairs of hexadecimal digits delimited by colons (e.g. 00:0A:E4:25:6B:B0), with a wildcard mask following the slash.

ipv6_src=ipv6[/netmask]
ipv6_dst=ipv6[/netmask] When dl_type is 0x86dd (possibly via shorthand, e.g., ipv6 or tcp6), matches IPv6 source (or destination) address ipv6, which may be specified as defined in RFC 2373. The preferred format is x:x:x:x:x:x:x:x, where x are the hexadecimal values of the eight 16-bit pieces of the address. A single instance of :: may be used to indicate multiple groups of 16-bits of zeros. The optional netmask allows restricting a match to an IPv6 address prefix. A netmask is specified as an IPv6 address (e.g. 2001:db8:3c4d:1::/ffff:ffff:ffff:ffff::) or a CIDR block (e.g. 2001:db8:3c4d:1::/64). 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.
ipv6_label=label When dl_type is 0x86dd (possibly via shorthand, e.g., ipv6 or tcp6), matches IPv6 flow label label.
nd_target=ipv6[/netmask] When dl_type, nw_proto, and icmp_type specify IPv6 Neighbor Discovery (ICMPv6 type 135 or 136), matches the target address ipv6. ipv6 is in the same format described earlier for the ipv6_src and ipv6_dst fields.
nd_sll=xx:xx:xx:xx:xx:xx When dl_type, nw_proto, and icmp_type 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.
nd_tll=xx:xx:xx:xx:xx:xx When dl_type, nw_proto, and icmp_type 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.
mpls_bos=bos When dl_type is 0x8847 or 0x8848 (possibly via shorthand e.g., mpls or mplsm), matches the bottom-of-stack bit of the outer-most MPLS label stack entry. Valid values are 0 and 1.
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.
mpls_label=label When dl_type is 0x8847 or 0x8848 (possibly via shorthand e.g., mpls or mplsm), matches the label of the outer MPLS label stack entry. The label is a 20-bit value that is decimal by default; use a 0x prefix to specify them in hexadecimal.
mpls_tc=tc When dl_type is 0x8847 or 0x8848 (possibly via shorthand e.g., mpls or mplsm), matches the traffic-class of the outer MPLS label stack entry. Valid values are between 0 (lowest) and 7 (highest).
tun_id=tunnel-id[/mask]
tunnel_id=tunnel-id[/mask] Matches tunnel identifier tunnel-id. 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 mask is omitted, tunnel-id is the exact tunnel ID to match; if mask is specified, then a 1-bit in mask indicates that the corresponding bit in tunnel-id must match exactly, and a 0-bit wildcards that bit.
tun_src=ip[/netmask]
tun_dst=ip[/netmask] Matches tunnel IPv4 source (or destination) address ip. 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. 192.168.1.1 or www.example.com). The optional netmask allows restricting a match to a masked IPv4 address. The netmask may be specified as a dotted quad (e.g. 192.168.1.0/255.255.255.0) or as a CIDR block (e.g. 192.168.1.0/24).
regidx=value[/mask] Matches value either exactly or with optional mask in register number idx. The valid range of idx depends on the switch. value and mask are 32-bit integers, by default in decimal (use a 0x prefix to specify hexadecimal). Arbitrary mask values are allowed: a 1-bit in mask indicates that the corresponding bit in value must match exactly, and a 0-bit wildcards that bit.
When a packet enters an OpenFlow switch, all of the registers are set to 0. Only explicit Nicira extension actions change register values.
pkt_mark=value[/mask] Matches packet metadata mark value either exactly or with optional mask. 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.
Defining IPv6 flows (those with dl_type equal to 0x86dd) requires support for NXM. The following shorthand notations are available for IPv6-related flows:
ipv6 Same as dl_type=0x86dd.
tcp6 Same as dl_type=0x86dd,nw_proto=6.
udp6 Same as dl_type=0x86dd,nw_proto=17.
sctp6 Same as dl_type=0x86dd,nw_proto=132.
icmp6 Same as dl_type=0x86dd,nw_proto=58.
Finally, field assignments to duration, n_packets, or n_bytes are ignored to allow output from the dump-flows command to be used as input for other commands that parse flows.
The add-flow, add-flows, and mod-flows commands require an additional field, which must be the final field specified:
actions=[action][,action...] Specifies a comma-separated list of actions to take on a packet when the flow entry matches. If no action is specified, then packets matching the flow are dropped. The following forms of action are supported:
port
output:port Outputs the packet to OpenFlow port number port. If port is the packet’s input port, the packet is not output.
output:src[start..end] Outputs the packet to the OpenFlow port number read from src, which must be an NXM field as described above. For example, output:NXM_NX_REG0[16..31] outputs to the OpenFlow port number written in the upper half of register 0. If the port number is the packet’s input port, the packet is not output.
This form of output was added in Open vSwitch 1.3.0. This form of output uses an OpenFlow extension that is not supported by standard OpenFlow switches.
normal Subjects the packet to the device’s normal L2/L3 processing. (This action is not implemented by all OpenFlow switches.)
flood Outputs the packet on all switch physical ports other than the port on which it was received and any ports on which flooding is disabled (typically, these would be ports disabled by the IEEE 802.1D spanning tree protocol).
all Outputs the packet on all switch physical ports other than the port on which it was received.
local Outputs the packet on the ‘‘local port,’’ which corresponds to the network device that has the same name as the bridge.
in_port Outputs the packet on the port from which it was received.
controller(key=value...) Sends the packet to the OpenFlow controller as a ‘‘packet in’’ message. The supported key-value pairs are:
max_len=nbytes Limit to nbytes the number of bytes of the packet to send to the controller. By default the entire packet is sent.
reason=reason Specify reason as the reason for sending the message in the ‘‘packet in’’ message. The supported reasons are action (the default), no_match, and invalid_ttl.
id=controller-id Specify controller-id, a 16-bit integer, as the connection ID of the OpenFlow controller or controllers to which the ‘‘packet in’’ message should be sent. The default is zero. Zero is also the default connection ID for each controller connection, and a given controller connection will only have a nonzero connection ID if its controller uses the NXT_SET_CONTROLLER_ID Nicira extension to OpenFlow.
Any reason other than action and any nonzero controller-id uses a Nicira vendor extension that, as of this writing, is only known to be implemented by Open vSwitch (version 1.6 or later).
controller
controller[:nbytes] Shorthand for controller() or controller(max_len=nbytes), respectively.
enqueue(port,queue) Enqueues the packet on the specified queue within port port, which must be an OpenFlow port number or keyword (e.g. LOCAL). The number of supported queues depends on the switch; some OpenFlow implementations do not support queuing at all.
drop Discards the packet, so no further processing or forwarding takes place. If a drop action is used, no other actions may be specified.
mod_vlan_vid:vlan_vid Modifies the VLAN id on a packet. The VLAN tag is added or modified as necessary to match the value specified. If the VLAN tag is added, a priority of zero is used (see the mod_vlan_pcp action to set this).
mod_vlan_pcp:vlan_pcp Modifies the VLAN priority on a packet. The VLAN tag is added or modified as necessary to match the value specified. Valid values are between 0 (lowest) and 7 (highest). If the VLAN tag is added, a vid of zero is used (see the mod_vlan_vid action to set this).
strip_vlan Strips the VLAN tag from a packet if it is present.
push_vlan:ethertype Push a new VLAN tag onto the packet. Ethertype is used as the the Ethertype for the tag. Only ethertype 0x8100 should be used. (0x88a8 which the spec allows isn’t supported at the moment.) A priority of zero and the tag of zero are used for the new tag.
push_mpls:ethertype Changes the packet’s Ethertype to ethertype, which must be either 0x8847 or 0x8848, and pushes an MPLS LSE.
If the packet does not already contain any MPLS labels then an initial label stack entry is pushed. The label stack entry’s label is 2 if the packet contains IPv6 and 0 otherwise, its default traffic control value is the low 3 bits of the packet’s DSCP value (0 if the packet is not IP), and its TTL is copied from the IP TTL (64 if the packet is not IP).
If the packet does already contain an MPLS label, pushes a new outermost label as a copy of the existing outermost label.
A limitation of the implementation is that processing of actions will stop if push_mpls follows another push_mpls unless there is a pop_mpls in between.
pop_mpls:ethertype Strips the outermost MPLS label stack entry. Currently the implementation restricts ethertype to a non-MPLS Ethertype and thus pop_mpls should only be applied to packets with an MPLS label stack depth of one. A further limitation is that processing of actions will stop if pop_mpls follows another pop_mpls unless there is a push_mpls in between.
mod_dl_src:mac Sets the source Ethernet address to mac.
mod_dl_dst:mac Sets the destination Ethernet address to mac.
mod_nw_src:ip Sets the IPv4 source address to ip.
mod_nw_dst:ip Sets the IPv4 destination address to ip.
mod_tp_src:port Sets the TCP or UDP or SCTP source port to port.
mod_tp_dst:port Sets the TCP or UDP or SCTP destination port to port.
mod_nw_tos:tos Sets the DSCP bits in the IPv4 ToS/DSCP or IPv6 traffic class field to tos, which must be a multiple of 4 between 0 and 255. This action does not modify the two least significant bits of the ToS field (the ECN bits).
mod_nw_ecn:ecn Sets the ECN bits in the IPv4 ToS or IPv6 traffic class field to ecn, which must be a value between 0 and 3, inclusive. This action does not modify the six most significant bits of the field (the DSCP bits).
Requires OpenFlow 1.1 or later.
mod_nw_ttl:ttl Sets the IPv4 TTL or IPv6 hop limit field to ttl, which is specified as a decimal number between 0 and 255, inclusive. Switch behavior when setting ttl to zero is not well specified, though.
Requires OpenFlow 1.1 or later.
The following actions are Nicira vendor extensions that, as of this writing, are only known to be implemented by Open vSwitch:
resubmit:port
resubmit([port],[table]) Re-searches this OpenFlow flow table (or the table whose number is specified by table) with the in_port field replaced by port (if port is specified) and executes the actions found, if any, in addition to any other actions in this flow entry.
Recursive resubmit 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 table.
set_tunnel:id
set_tunnel64:id If outputting to a port that encapsulates the packet in a tunnel and supports an identifier (such as GRE), sets the identifier to id. If the set_tunnel form is used and id fits in 32 bits, then this uses an action extension that is supported by Open vSwitch 1.0 and later. Otherwise, if id is a 64-bit value, it requires Open vSwitch 1.1 or later.
set_queue:queue Sets the queue that should be used to queue when packets are output. The number of supported queues depends on the switch; some OpenFlow implementations do not support queuing at all.
pop_queue Restores the queue to the value it was before any set_queue actions were applied.
dec_ttl
dec_ttl[(id1,id2)] Decrement TTL of IPv4 packet or hop limit of IPv6 packet. If the TTL or hop limit is initially zero or decrementing would make it so, no decrement occurs, as packets reaching TTL zero must be rejected. Instead, a ‘‘packet-in’’ message with reason code OFPR_INVALID_TTL is sent to each connected controller that has enabled receiving them, if any. Processing the current set of actions then stops. However, if the current set of actions was reached through ‘‘resubmit’’ then remaining actions in outer levels resume processing. This action also optionally supports the ability to specify a list of valid controller ids. Each of controllers in the list will receive the ‘‘packet_in’’ message only if they have registered to receive the invalid ttl packets. If controller ids are not specified, the ‘‘packet_in’’ message will be sent only to the controllers having controller id zero which have registered for the invalid ttl packets.
set_mpls_label:label Set the label of the outer MPLS label stack entry of a packet. label should be a 20-bit value that is decimal by default; use a 0x prefix to specify them in hexadecimal.
set_mpls_tc:tc Set the traffic-class of the outer MPLS label stack entry of a packet. tc should be a in the range 0 to 7 inclusive.
set_mpls_ttl:ttl Set the TTL of the outer MPLS label stack entry of a packet. ttl should be in the range 0 to 255 inclusive.
dec_mpls_ttl Decrement TTL of the outer MPLS label stack entry of a packet. If the TTL is initially zero or decrementing would make it so, no decrement occurs. Instead, a ‘‘packet-in’’ message with reason code OFPR_INVALID_TTL is sent to the main controller (id zero), if it has enabled receiving them. Processing the current set of actions then stops. However, if the current set of actions was reached through ‘‘resubmit’’ then remaining actions in outer levels resume processing.
note:[hh]... Does nothing at all. Any number of bytes represented as hex digits hh may be included. Pairs of hex digits may be separated by periods for readability. The note action’s format doesn’t include an exact length for its payload, so the provided bytes will be padded on the right by enough bytes with value 0 to make the total number 6 more than a multiple of 8.
move:src[start..end]->dst[start..end] Copies the named bits from field src to field dst. src and dst must be NXM field names as defined in nicira-ext.h, e.g. NXM_OF_UDP_SRC or NXM_NX_REG0. Each start and end pair, which are inclusive, must specify the same number of bits and must fit within its respective field. Shorthands for [start..end] exist: use [bit] to specify a single bit or [] to specify an entire field.
Examples: move:NXM_NX_REG0[0..5]->NXM_NX_REG1[26..31] copies the six bits numbered 0 through 5, inclusive, in register 0 into bits 26 through 31, inclusive; move:NXM_NX_REG0[0..15]->NXM_OF_VLAN_TCI[] copies the least significant 16 bits of register 0 into the VLAN TCI field.
load:value->dst[start..end] Writes value to bits start through end, inclusive, in field dst.
Example: load:55->NXM_NX_REG2[0..5] loads value 55 (bit pattern 110111) into bits 0 through 5, inclusive, in register 2.
push:src[start..end] Pushes start to end bits inclusive, in fields on top of the stack.
Example: push:NXM_NX_REG2[0..5] push the value stored in register 2 bits 0 through 5, inclusive, on to the internal stack.
pop:dst[start..end] Pops from the top of the stack, retrieves the start to end bits inclusive, from the value popped and store them into the corresponding bits in dst.
Example: pop:NXM_NX_REG2[0..5] 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.
set_field:value->dst Writes the literal value into the field dst, which should be specified as a name used for matching. (This is similar to load but more closely matches the set-field action defined in OpenFlow 1.2 and above.)
Example: set_field:00:11:22:33:44:55->eth_src.
multipath(fields, basis, algorithm, n_links, arg, dst[start..end]) Hashes fields using basis as a universal hash parameter, then the applies multipath link selection algorithm (with parameter arg) to choose one of n_links output links numbered 0 through n_links minus 1, and stores the link into dst[start..end], which must be an NXM field as described above.
Currently, fields must be either eth_src or symmetric_l4 and algorithm must be one of modulo_n, hash_threshold, hrw, and iter_hash. Only the iter_hash algorithm uses arg.
Refer to nicira-ext.h for more details.
bundle(fields, basis, algorithm, slave_type, slaves:[s1, s2, ...]) Hashes fields using basis as a universal hash parameter, then applies the bundle link selection algorithm to choose one of the listed slaves represented as slave_type. Currently the only supported slave_type is ofport. Thus, each s1 through sN should be an OpenFlow port number. Outputs to the selected slave.
Currently, fields must be either eth_src or symmetric_l4 and algorithm must be one of hrw and active_backup.
Example: bundle(eth_src,0,hrw,ofport,slaves:4,8) uses an Ethernet source hash with basis 0, to select between OpenFlow ports 4 and 8 using the Highest Random Weight algorithm.
Refer to nicira-ext.h for more details.
bundle_load(fields, basis, algorithm, slave_type, dst[start..end], slaves:[s1, s2, ...]) Has the same behavior as the bundle action, with one exception. Instead of outputting to the selected slave, it writes its selection to dst[start..end], which must be an NXM field as described above.
Example: bundle_load(eth_src, 0, hrw, ofport, NXM_NX_REG0[], slaves:4, 8) uses an Ethernet source hash with basis 0, to select between OpenFlow ports 4 and 8 using the Highest Random Weight algorithm, and writes the selection to NXM_NX_REG0[].
Refer to nicira-ext.h for more details.
learn(argument[,argument]...) This action adds or modifies a flow in an OpenFlow table, similar to ovs-ofctl --strict mod-flows. The arguments specify the flow’s match fields, actions, and other properties, as follows. At least one match criterion and one action argument should ordinarily be specified.
idle_timeout=seconds
hard_timeout=seconds
priority=value These key-value pairs have the same meaning as in the usual ovs-ofctl flow syntax.
fin_idle_timeout=seconds
fin_hard_timeout=seconds Adds a fin_timeout action with the specified arguments to the new flow. This feature was added in Open vSwitch 1.5.90.
table=number The table in which the new flow should be inserted. Specify a decimal number between 0 and 254. The default, if table is unspecified, is table 1.
field=value
field[start..end]=src[start..end]
field[start..end] Adds a match criterion to the new flow.
The first form specifies that field must match the literal value, e.g. dl_type=0x0800. All of the fields and values for ovs-ofctl flow syntax are available with their usual meanings.
The second form specifies that field[start..end] in the new flow must match src[start..end] taken from the flow currently being processed.
The third form is a shorthand for the second form. It specifies that field[start..end] in the new flow must match field[start..end] taken from the flow currently being processed.
load:value->dst[start..end]
load:src[start..end]->dst[start..end] Adds a load action to the new flow.
The first form loads the literal value into bits start through end, inclusive, in field dst. Its syntax is the same as the load action described earlier in this section.
The second form loads src[start..end], a value from the flow currently being processed, into bits start through end, inclusive, in field dst.
output:field[start..end] Add an output action to the new flow’s actions, that outputs to the OpenFlow port taken from field[start..end], which must be an NXM field as described above.
For best performance, segregate learned flows into a table (using table=number) that is not used for any other flows except possibly for a lowest-priority ‘‘catch-all’’ flow, that is, a flow with no match criteria. (This is why the default table is 1, to keep the learned flows separate from the primary flow table 0.)
apply_actions([action][,action...]) Applies the specific action(s) immediately. The syntax of actions are same to actions= field.
clear_actions Clears all the actions in the action set immediately.
write_actions([action][,action...]) Add the specific actions to the action set. The syntax of actions is the same as in the actions= field. The action set is carried between flow tables and then executed at the end of the pipeline.
The actions in the action set are applied in the following order, as required by the OpenFlow specification, regardless of the order in which they were added to the action set. Except as specified otherwise below, the action set only holds at most a single action of each type. When more than one action of a single type is written to the action set, the one written later replaces the earlier action:
1. strip_vlan
pop_mpls
2. push_mpls
3. push_vlan
4. dec_ttl
dec_mpls_ttl
5. load
mod_dl_dst
mod_dl_src
mod_nw_dst
mod_nw_src
mod_nw_tos
mod_nw_ecn
mod_nw_ttl
mod_tp_dst
mod_tp_src
mod_vlan_pcp
mod_vlan_vid
set_field
set_tunnel
set_tunnel64
The action set can contain any number of these actions, with cumulative effect. 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.
6. set_queue
7. group
output
If both actions are present, then group is executed and output is ignored, regardless of the order in which they were added to the action set. (If neither action is present, the action set has no real effect, because the modified packet is not sent anywhere and thus the modifications are not visible.)
Only the actions listed above may be written to the action set.
write_metadata:value[/mask] Updates the metadata field for the flow. If mask is omitted, the metadata field is set exactly to value; if mask is specified, then a 1-bit in mask indicates that the corresponding bit in the metadata field will be replaced with the corresponding bit from value. Both value and mask are 64-bit values that are decimal by default; use a 0x prefix to specify them in hexadecimal.
meter:meter_id Apply the meter_id before any other actions. If a meter band rate is exceeded, the packet may be dropped, or modified, depending on the meter band type. See the description of the Meter Table Commands, above, for more details.
goto_table:table Indicates the next table in the process pipeline.
fin_timeout(argument[,argument]) This action changes the idle timeout or hard timeout, or both, of this OpenFlow rule when the rule matches a TCP packet with the FIN or RST flag. When such a packet is observed, the action reduces the rule’s timeouts to those specified on the action. If the rule’s existing timeout is already shorter than the one that the action specifies, then that timeout is unaffected.
argument takes the following forms:
idle_timeout=seconds Causes the flow to expire after the given number of seconds of inactivity.
hard_timeout=seconds Causes the flow to expire after the given number of seconds, regardless of activity. (seconds specifies time since the flow’s creation, not since the receipt of the FIN or RST.)
This action was added in Open vSwitch 1.5.90.
sample(argument[,argument]...) Samples packets and sends one sample for every sampled packet.
argument takes the following forms:
probability=packets The number of sampled packets out of 65535. Must be greater or equal to 1.
collector_set_id=id The unsigned 32-bit integer identifier of the set of sample collectors to send sampled packets to. Defaults to 0.
obs_domain_id=id When sending samples to IPFIX collectors, the unsigned 32-bit integer Observation Domain ID sent in every IPFIX flow record. Defaults to 0.
obs_point_id=id When sending samples to IPFIX collectors, the unsigned 32-bit integer Observation Point ID sent in every IPFIX flow record. Defaults to 0.
Refer to ovs-vswitchd.conf.db(8) for more details on configuring sample collector sets.
This action was added in Open vSwitch 1.10.90.
exit This action causes Open vSwitch to immediately halt execution of further actions. Those actions which have already been executed are unaffected. Any further actions, including those which may be in other tables, or different levels of the resubmit call stack, are ignored. Actions in the action set is still executed (specify clear_actions before exit to discard them).
An opaque identifier called a cookie can be used as a handle to identify a set of flows:
cookie=value A cookie can be associated with a flow using the add-flow, add-flows, and mod-flows commands. value can be any 64-bit number and need not be unique among flows. If this field is omitted, a default cookie value of 0 is used.
cookie=value/mask When using NXM, the cookie can be used as a handle for querying, modifying, and deleting flows. value and mask may be supplied for the del-flows, mod-flows, dump-flows, and dump-aggregate commands to limit matching cookies. A 1-bit in mask indicates that the corresponding bit in cookie must match exactly, and a 0-bit wildcards that bit. A mask of -1 may be used to exactly match a cookie.
The mod-flows command can update the cookies of flows that match a cookie by specifying the cookie field twice (once with a mask for matching and once without to indicate the new value):
ovs-ofctl mod-flows br0 cookie=1,actions=normal Change all flows’ cookies to 1 and change their actions to normal.
ovs-ofctl mod-flows br0 cookie=1/-1,cookie=2,actions=normal Update cookies with a value of 1 to 2 and change their actions to normal.
The ability to match on cookies was added in Open vSwitch 1.5.0.
The following additional field sets the priority for flows added by the add-flow and add-flows commands. For mod-flows and del-flows when --strict is specified, priority must match along with the rest of the flow specification. For mod-flows without --strict, priority is only significant if the command creates a new flow, that is, non-strict mod-flows does not match on priority and will not change the priority of existing flows. Other commands do not allow priority to be specified.
priority=value The priority at which a wildcarded entry will match in comparison to others. value is a number between 0 and 65535, inclusive. A higher value will match before a lower one. An exact-match entry will always have priority over an entry containing wildcards, so it has an implicit priority value of 65535. When adding a flow, if the field is not specified, the flow’s priority will default to 32768.
OpenFlow leaves behavior undefined when two or more flows with the same priority can match a single packet. Some users expect ‘‘sensible’’ behavior, such as more specific flows taking precedence over less specific flows, but OpenFlow does not specify this and Open vSwitch does not implement it. Users should therefore take care to use priorities to ensure the behavior that they expect.
The add-flow, add-flows, and mod-flows commands support the following additional options. These options affect only new flows. Thus, for add-flow and add-flows, these options are always significant, but for mod-flows they are significant only if the command creates a new flow, that is, their values do not update or affect existing flows.
idle_timeout=seconds Causes the flow to expire after the given number of seconds of inactivity. A value of 0 (the default) prevents a flow from expiring due to inactivity.
hard_timeout=seconds Causes the flow to expire after the given number of seconds, regardless of activity. A value of 0 (the default) gives the flow no hard expiration deadline.
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.)
The dump-flows, dump-aggregate, del-flow and del-flows commands support one additional optional field:
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).

    Table Entry Output

The dump-tables and dump-aggregate commands print information about the entries in a datapath’s tables. Each line of output is a flow entry as described in Flow Syntax, above, plus some additional fields:
duration=secs The time, in seconds, that the entry has been in the table. secs includes as much precision as the switch provides, possibly to nanosecond resolution.
n_packets The number of packets that have matched the entry.
n_bytes The total number of bytes from packets that have matched the entry.
The following additional fields are included only if the switch is Open vSwitch 1.6 or later and the NXM flow format is used to dump the flow (see the description of the --flow-format option below). The values of these additional fields are approximations only and in particular idle_age will sometimes become nonzero even for busy flows.
hard_age=secs The integer number of seconds since the flow was added or modified. hard_age is displayed only if it differs from the integer part of duration. (This is separate from duration because mod-flows restarts the hard_timeout timer without zeroing duration.)
idle_age=secs The integer number of seconds that have passed without any packets passing through the flow.

    Group Syntax

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

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

type=type The type of the group. This add-group, add-groups and del-groups command require this field. The following keywords designated the allowed types:
all Execute all buckets in the group.
select 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.
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.

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 syntax of actions are same to actions= field described in Flow Syntax above. The fields for bucket_parameters are:
weight=value The relative weight of the bucket as an integer. This may be used by the switch during bucket select for groups whose type is select.
watch_port=port Port used to determine liveness of group. This or the watch_group field is required for groups whose type is ff or fast_failover.
watch_group=group_id Group identifier of group used to determine liveness of group. This or the watch_port field is required for groups whose type is ff or fast_failover.

    Meter Syntax

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

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

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

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

stats Collect meter and band statistics.

bands=band_parameters The add-meter and mod-meter commands require at least one band specification. Bands must appear after all other fields.
type=type The type of the meter band. This keyword starts a new band specification. Each band specifies a rate above which the band is to take some action. The action depends on the band type. If multiple bands’ rate is exceeded, then the band with the highest rate among the exceeded bands is selected. The following keywords designate the allowed meter band types:
drop Drop packets exceeding the band’s rate limit.
The other band_parameters are:
rate=value The relative rate limit for this band, in kilobits per second or packets per second, depending on the meter flags defined above.
burst_size=port The maximum burst allowed for the band. If unspecified, the switch is free to select some reasonable value depending on it’s configuration.

OPTIONS

--strict
  Uses strict matching when running flow modification commands.
-O [version[,version]...]
--protocols=[version[,version]...] Sets the OpenFlow protocol versions that are allowed when establishing an OpenFlow session.
The following versions are considered to be ready for general use. These protocol versions are enabled by default:
o OpenFlow10, for OpenFlow 1.0.
Support for the following protocol versions is provided for testing and development purposes. They are not enabled by default:
o OpenFlow11, for OpenFlow 1.1.
o OpenFlow12, for OpenFlow 1.2.
o OpenFlow13, for OpenFlow 1.3.
-F format[,format...]
--flow-format=format[,format...] ovs-ofctl supports the following individual flow formats, any number of which may be listed as format:
OpenFlow10-table_id This is the standard OpenFlow 1.0 flow format. All OpenFlow switches and all versions of Open vSwitch support this flow format.
OpenFlow10+table_id This is the standard OpenFlow 1.0 flow format plus a Nicira extension that allows ovs-ofctl to specify the flow table in which a particular flow should be placed. Open vSwitch 1.2 and later supports this flow format.
NXM-table_id (Nicira Extended Match) This Nicira extension to OpenFlow is flexible and extensible. It supports all of the Nicira flow extensions, such as tun_id and registers. Open vSwitch 1.1 and later supports this flow format.
NXM+table_id (Nicira Extended Match) This combines Nicira Extended match with the ability to place a flow in a specific table. Open vSwitch 1.2 and later supports this flow format.
OXM-OpenFlow12
OXM-OpenFlow13
OXM-OpenFlow14 These are the standard OXM (OpenFlow Extensible Match) flow format in OpenFlow 1.2, 1.3, and 1.4, respectively.
ovs-ofctl also supports the following abbreviations for collections of flow formats:
any Any supported flow format.
OpenFlow10 OpenFlow10-table_id or OpenFlow10+table_id.
NXM NXM-table_id or NXM+table_id.
OXM OXM-OpenFlow12, OXM-OpenFlow13, or OXM-OpenFlow14.
For commands that modify the flow table, ovs-ofctl by default negotiates the most widely supported flow format that supports the flows being added. For commands that query the flow table, ovs-ofctl by default uses the most advanced format supported by the switch.
This option, where format is a comma-separated list of one or more of the formats listed above, limits ovs-ofctl’s choice of flow format. If a command cannot work as requested using one of the specified flow formats, ovs-ofctl will report a fatal error.
-P format
--packet-in-format=format ovs-ofctl supports the following packet_in formats, in order of increasing capability:
openflow10 This is the standard OpenFlow 1.0 packet in format. It should be supported by all OpenFlow switches.
nxm (Nicira Extended Match) This packet_in format includes flow metadata encoded using the NXM format.
Usually, ovs-ofctl prefers the nxm packet_in format, but will allow the switch to choose its default if nxm is unsupported. When format is one of the formats listed in the above table, ovs-ofctl will insist on the selected format. If the switch does not support the requested format, ovs-ofctl will report a fatal error. This option only affects the monitor command.
--timestamp Print a timestamp before each received packet. This option only affects the monitor, snoop, and ofp-parse-pcap commands.
-m
--more Increases the verbosity of OpenFlow messages printed and logged by ovs-ofctl commands. Specify this option more than once to increase verbosity further.
--sort[=field]
--rsort[=field] Display output sorted by flow field in ascending (--sort) or descending (--rsort) order, where field is any of the fields that are allowed for matching or priority to sort by priority. When field is omitted, the output is sorted by priority. Specify these options multiple times to sort by multiple fields.
Any given flow will not necessarily specify a value for a given field. This requires special treatement:
o A flow that does not specify any part of a field that is used for sorting is sorted after all the flows that do specify the field. For example, --sort=tcp_src will sort all the flows that specify a TCP source port in ascending order, followed by the flows that do not specify a TCP source port at all.
o A flow that only specifies some bits in a field is sorted as if the wildcarded bits were zero. For example, --sort=nw_src would sort a flow that specifies nw_src=192.168.0.0/24 the same as nw_src=192.168.0.0.
These options currently affect only dump-flows output. ovs-ofctl detaches only when executing the monitor or snoop commands. The following options are valid on POSIX based platforms.
--pidfile[=pidfile]
  Causes a file (by default, ovs-ofctl.pid) to be created indicating the PID of the running process. If the pidfile argument is not specified, or if it does not begin with /, then it is created in /var/run/openvswitch.
If --pidfile is not specified, no pidfile is created.
--overwrite-pidfile
  By default, when --pidfile is specified and the specified pidfile already exists and is locked by a running process, ovs-ofctl refuses to start. Specify --overwrite-pidfile to cause it to instead overwrite the pidfile.
When --pidfile is not specified, this option has no effect.
--detach
  Causes ovs-ofctl to detach itself from the foreground session and run as a background process.
--monitor
  Creates an additional process to monitor the ovs-ofctl daemon. If the daemon dies due to a signal that indicates a programming error (SIGABRT, SIGALRM, SIGBUS, SIGFPE, SIGILL, SIGPIPE, SIGSEGV, SIGXCPU, or SIGXFSZ) then the monitor process starts a new copy of it. If the daemon dies or exits for another reason, the monitor process exits.
This option is normally used with --detach, but it also functions without it.
--no-chdir
  By default, when --detach is specified, ovs-ofctl changes its current working directory to the root directory after it detaches. Otherwise, invoking ovs-ofctl from a carelessly chosen directory would prevent the administrator from unmounting the file system that holds that directory.
Specifying --no-chdir suppresses this behavior, preventing ovs-ofctl from changing its current working directory. This may be useful for collecting core files, since it is common behavior to write core dumps into the current working directory and the root directory is not a good directory to use.
This option has no effect when --detach is not specified.
--unixctl=socket Sets the name of the control socket on which ovs-ofctl listens for runtime management commands (see RUNTIME MANAGEMENT COMMANDS, below). If socket does not begin with /, it is interpreted as relative to /var/run/openvswitch. If --unixctl is not used at all, the default socket is /var/run/openvswitch/ovs-ofctl.pid.ctl, where pid is ovs-ofctl’s process ID.
On Windows, uses a kernel chosen TCP port on the localhost to listen for runtime management commands. The kernel chosen TCP port value is written in a file whose absolute path is pointed by socket. If --unixctl is not used at all, the file is created as ovs-ofctl.ctl in the configured OVS_RUNDIR directory.
Specifying none for socket disables the control socket feature.

    Public Key Infrastructure Options

-p privkey.pem
--private-key=privkey.pem Specifies a PEM file containing the private key used as ovs-ofctl’s identity for outgoing SSL connections.
-c cert.pem
--certificate=cert.pem Specifies a PEM file containing a certificate that certifies the private key specified on -p or --private-key to be trustworthy. The certificate must be signed by the certificate authority (CA) that the peer in SSL connections will use to verify it.
-C cacert.pem
--ca-cert=cacert.pem Specifies a PEM file containing the CA certificate that ovs-ofctl should use to verify certificates presented to it by SSL peers. (This may be the same certificate that SSL peers use to verify the certificate specified on -c or --certificate, or it may be a different one, depending on the PKI design in use.)
-C none
--ca-cert=none Disables verification of certificates presented by SSL peers. This introduces a security risk, because it means that certificates cannot be verified to be those of known trusted hosts.
-v[spec]
--verbose=[spec] Sets logging levels. Without any spec, sets the log level for every module and facility to dbg. Otherwise, spec is a list of words separated by spaces or commas or colons, up to one from each category below:
o A valid module name, as displayed by the vlog/list command on ovs-appctl(8), limits the log level change to the specified module.
o syslog, console, or file, to limit the log level change to only to the system log, to the console, or to a file, respectively.
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).
o off, emer, err, warn, info, or dbg, to control the log level. Messages of the given severity or higher will be logged, and messages of lower severity will be filtered out. off filters out all messages. See ovs-appctl(8) for a definition of each log level.
Case is not significant within spec.
Regardless of the log levels set for file, logging to a file will not take place unless --log-file is also specified (see below).
For compatibility with older versions of OVS, any is accepted as a word but has no effect.
-v
--verbose Sets the maximum logging verbosity level, equivalent to --verbose=dbg.
-vPATTERN:facility:pattern
--verbose=PATTERN:facility:pattern Sets the log pattern for facility to pattern. Refer to ovs-appctl(8) for a description of the valid syntax for pattern.
--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 /var/log/openvswitch/ovs-ofctl.log.
--syslog-target=host:port Send syslog messages to UDP port on host, in addition to the system syslog. The host must be a numerical IP address, not a hostname.
-h
--help Prints a brief help message to the console.
-V
--version Prints version information to the console.

RUNTIME MANAGEMENT COMMANDS

ovs-appctl(8) can send commands to a running ovs-ofctl process. The supported commands are listed below.
exit Causes ovs-ofctl to gracefully terminate. This command applies only when executing the monitor or snoop commands.
ofctl/set-output-file file Causes all subsequent output to go to file instead of stderr. This command applies only when executing the monitor or snoop commands.
ofctl/send ofmsg... Sends each ofmsg, specified as a sequence of hex digits that express an OpenFlow message, on the OpenFlow connection. This command is useful only when executing the monitor command.
ofctl/barrier Sends an OpenFlow barrier request on the OpenFlow connection and waits for a reply. This command is useful only for the monitor command.

EXAMPLES

The following examples assume that ovs-vswitchd has a bridge named br0 configured.
ovs-ofctl dump-tables br0
  Prints out the switch’s table stats. (This is more interesting after some traffic has passed through.)
ovs-ofctl dump-flows br0
  Prints the flow entries in the switch.

SEE ALSO

ovs-appctl(8), ovs-vswitchd(8) ovs-vswitchd.conf.db(8)
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Open vSwitch OVS-OFCTL (8) 2.3.2

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