FLOWADM(8) Maintenance Commands and Procedures FLOWADM(8)

flowadm - administer bandwidth resource control and priority for protocols, services, containers, and virtual machines

flowadm add-flow [-t] [-R root-dir] -l link -a attr=value[,...]


     [-p prop=value[,...]] flow
flowadm remove-flow [-t] [-R root-dir] {-l link | flow}
flowadm show-flow [-p] [-l link] [-o field[,...]] [flow]

flowadm set-flowprop [-t] [-R root-dir] -p prop=value[,...] flow
flowadm reset-flowprop [-t] [-R root-dir] [-p prop[,...]] flow
flowadm show-flowprop [-cP] [-l link] [-o field[,...]]


     [-p prop[,...]] [flow]

The flowadm command is used to create, modify, remove, and show networking bandwidth and associated resources for a type of traffic on a particular link.

The flowadm command allows users to manage networking bandwidth resources for a transport, service, or a subnet. The service is specified as a combination of transport and local port. The subnet is specified by its IP address and subnet mask. The command can be used on any type of data link, including physical links, virtual NICs, and link aggregations.

A flow is defined as a set of attributes based on Layer 3 and Layer 4 headers, which can be used to identify a protocol, service, or a virtual machine. When a flow is identified based on flow attributes, separate kernel resources including layer 2, 3, and 4 queues, their processing threads, and other resources are uniquely created for it, such that other traffic has minimal or zero impact on it.

Inbound and outbound packet are matched to flows in a very fast and scalable way, so that limits can be enforced with minimal performance impact.

The flowadm command can be used to define a flow without imposing any bandwidth resource control. This would result in the traffic type getting its own resources and queues so that it is isolated from rest of the networking traffic for more observable and deterministic behavior.

flowadm is implemented as a set of subcommands with corresponding options. Options are described in the context of each subcommand.

The following subcommands are supported:

flowadm add-flow [-t] [-R root-dir] -l link -a attr=value[,...] [-p prop=value[,...]] flow

Adds a flow to the system. The flow is identified by its flow attributes and properties.

As part of identifying a particular flow, its bandwidth resource can be limited and its relative priority to other traffic can be specified. If no bandwidth limit or priority is specified, the traffic still gets its unique layer 2, 3, and 4 queues and processing threads, including NIC hardware resources (when supported), so that the selected traffic can be separated from others and can flow with minimal impact from other traffic.

-t, --temporary

The changes are temporary and will not persist across reboots. Persistence is the default.

-R root-dir, --root-dir=root-dir

Specifies an alternate root directory where flowadm should apply persistent creation.

-l link, --link=link

Specify the link to which the flow will be added.

-a attr=value[,...], --attr=value

A mandatory comma-separated list of attributes to be set to the specified values.

-p prop=value[,...], --prop=value[,...]

An optional comma-separated list of properties to be set to the specified values. Flow properties are documented in the "Flow Properties" section, below.

flowadm remove-flow [-t] [-R root-dir] -l {link | flow}

Remove an existing flow identified by its link or name.

-t, --temporary

The changes are temporary and will not persist across reboots. Persistence is the default.

-R root-dir, --root-dir=root-dir

Specifies an alternate root directory where flowadm should apply persistent removal.

-l link | flow, --link=link | flow

If a link is specified, remove all flows from that link. If a single flow is specified, remove only that flow.

flowadm show-flow [-pP] [-s [-i interval]] [-o field[,...]] [-l link] [flow]

Show flow configuration information, either for all flows, all flows on a link, or for the specified flow.

-o field[,...]

A case-insensitive, comma-separated list of output fields to display. The field name must be one of the fields listed below, or a special value all, to display all fields. For each flow found, the following fields can be displayed:

flow

The name of the flow.

link

The name of the link the flow is on.

ipaddr

IP address of the flow. This can be either local or remote depending on how the flow was defined.

proto

The name of the layer for protocol to be used.

lport

Local port of service for flow.

rport

Remote port of service for flow.

dsfld

Differentiated services value for flow and mask used with DSFIELD value to state the bits of interest in the differentiated services field of the IP header.

-p, --parsable

Display using a stable machine-parsable format.

-P, --persistent

Display persistent flow property information.

-l link, --link=link | flow

Display information for all flows on the named link or information for the named flow.

flowadm set-flowprop [-t] [-R root-dir] -p prop=value[,...] flow

Set values of one or more properties on the flow specified by name. The complete list of properties can be retrieved using the show-flowprop subcommand.

-t, --temporary

The changes are temporary and will not persist across reboots. Persistence is the default.

-R root-dir, --root-dir=root-dir

Specifies an alternate root directory where flowadm should apply persistent setting of properties.

-p prop=value[,...], --prop=value[,...]

A comma-separated list of properties to be set to the specified values.

flowadm reset-flowprop [-t] [-R root-dir] -p [prop=value[,...]] flow

Resets one or more properties to their default values on the specified flow. If no properties are specified, all properties are reset. See the show-flowprop subcommand for a description of properties, which includes their default values.

-t, --temporary

Specifies that the resets are temporary. Temporary resets last until the next reboot.

-R root-dir, --root-dir=root-dir

Specifies an alternate root directory where flowadm should apply persistent setting of properties.

-p prop=value[,...], --prop=value[,...]

A comma-separated list of properties to be reset.

flowadm show-flowprop [-cP] [-l link] [-p prop[,...]] [flow]

Show the current or persistent values of one or more properties, either for all flows, flows on a specified link, or for the specified flow.

By default, current values are shown. If no properties are specified, all available flow properties are displayed. For each property, the following fields are displayed:

FLOW

The name of the flow.

PROPERTY

The name of the property.

VALUE

The current (or persistent) property value. The value is shown as -- (double hyphen), if it is not set, and ? (question mark), if the value is unknown. Persistent values that are not set or have been reset will be shown as -- and will use the system DEFAULT value (if any).

DEFAULT

The default value of the property. If the property has no default value, -- (double hyphen), is shown.

POSSIBLE

A comma-separated list of the values the property can have. If the values span a numeric range, the minimum and maximum values might be shown as shorthand. If the possible values are unknown or unbounded, -- (double hyphen), is shown.

Flow properties are documented in the "Flow Properties" section, below.

-c

Display using a stable machine-parsable format.

-P, --persistent

Display persistent flow property information.

-p prop[,...], --prop=prop[,...]

A comma-separated list of properties to show.

The flow operand that identifies a flow in a flowadm command is a comma-separated list of one or more keyword, value pairs from the list below.

local_ip=value[/prefix_len]

Identifies a network flow by the local IP address. value must be a IPv4 address in dotted-decimal notation or an IPv6 address in colon-separated notation. prefix_len is optional.

If prefix_len is specified, it describes the netmask for a subnet address, following the same notation convention of ifconfig(8) and route(8) addresses. If unspecified, the given IP address will be considered as a host address for which the default prefix length for a IPv4 address is /32 and for IPv6 is /128.

remote_ip=value[/prefix_len]

Identifies a network flow by the remote IP address. The syntax is the same as the local_ip attribute.

transport={tcp|udp|sctp|icmp|icmpv6}

Identifies a layer 4 protocol to be used. It is typically used in combination with local_port to identify the service that needs special attention.

local_port=port

Identifies a service specified by the local port.

remote_port=port

Identifies a service specified by the remote port.

dsfield=value[:dsfield_mask]

Identifies the 8-bit differentiated services field (as defined in RFC 2474).

The optional dsfield_mask is used to state the bits of interest in the differentiated services field when comparing with the dsfield value. A 0 in a bit position indicates that the bit value needs to be ignored and a 1 indicates otherwise. The mask can range from 0x01 to 0xff. If dsfield_mask is not specified, the default mask 0xff is used. Both the dsfield value and mask must be in hexadecimal.

The following six types of combinations of attributes are supported:


local_ip=address[/prefixlen]
remote_ip=address[/prefixlen]
transport={tcp|udp|sctp|icmp|icmpv6}
transport={tcp|udp|sctp},local_port=port
transport={tcp|udp|sctp},remote_port=port
dsfield=val[:dsfield_mask]

On a given link, the types of combinations above are mutually exclusive. An attempt to create flows of different types on a given link will fail.

There are individual flow restrictions and flow restrictions per zone.

Restrictions on individual flows do not require knowledge of other flows that have been added to the link.

An attribute can be listed only once for each flow. For example, the following command is not valid:


# flowadm add-flow -l vnic1 -a local_port=80,local_port=8080 httpflow

transport and local_port:

TCP, UDP, or SCTP flows can be specified with a local port. An ICMP or ICMPv6 flow that specifies a port is not allowed. The following commands are valid:


# flowadm add-flow -l e1000g0 -a transport=udp udpflow
# flowadm add-flow -l e1000g0 -a transport=tcp,local_port=80 \
udp80flow

The following commands are not valid:


# flowadm add-flow -l e1000g0 -a local_port=25 flow25
# flowadm add-flow -l e1000g0 -a transport=icmpv6,local_port=16 \
flow16

Within a zone, no two flows can have the same name. After adding a flow with the link specified, the link will not be required for display, modification, or deletion of the flow.

The following flow properties are supported. Note that the ability to set a given property to a given value depends on the driver and hardware.

maxbw

Sets the full duplex bandwidth for the flow. The bandwidth is specified as an integer with one of the scale suffixes(K, M, or G for Kbps, Mbps, and Gbps). If no units are specified, the input value will be read as Mbps. The default is no bandwidth limit.

priority

Sets the relative priority for the flow. The value can be given as one of the tokens high, medium, or low. The default is medium.

Example 1 Creating a Policy Around a Mission-Critical Port

The command below creates a policy around inbound HTTPS traffic on an HTTPS server so that HTTPS obtains dedicated NIC hardware and kernel TCP/IP resources. The name specified, https-1, can be used later to modify or delete the policy.


# flowadm add-flow -l bge0 -a transport=TCP,local_port=443 https-1
# flowadm show-flow -l bge0
FLOW         LINK       IPADDR                   PROTO  LPORT   RPORT   DSFLD
https1       bge0       --                       tcp    443     --      --

Example 2 Modifying an Existing Policy to Add Bandwidth Resource Control

The following command modifies the https-1 policy from the preceding example. The command adds bandwidth control and give the policy a high priority.


# flowadm set-flowprop -p maxbw=500M,priority=high https-1
# flowadm show-flow https-1
FLOW        LINK        IPADDR                   PROTO  LPORT   RPORT   DSFLD
https-1     bge0        --                       tcp    443     --      --
# flowadm show-flowprop https-1
FLOW         PROPERTY        VALUE          DEFAULT        POSSIBLE
https-1      maxbw             500          --             --
https-1      priority        high           --             low,medium,high

Example 3 Limiting the UDP Bandwidth Usage

The following command creates a policy for UDP protocol so that it cannot consume more than 100Mbps of available bandwidth. The flow is named limit-udp-1.


# flowadm add-flow -l bge0 -a transport=UDP -p maxbw=100M, \
priority=low limit-udp-1

Example 4 Setting Policy, Making Use of dsfield Attribute

The following command sets a policy for EF PHB (DSCP value of 101110 from RFC 2598) with a bandwidth of 500 Mbps and a high priority. The dsfield value for this flow will be 0x2e (101110) with the dsfield_mask being 0xfc (because we want to ignore the 2 least significant bits).


# flowadm add-flow -l bge0 -a dsfield=0x2e:0xfc \
-p maxbw=500M,priority=high efphb-flow

0

All actions were performed successfully.

>0

An error occurred.

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Committed

attributes(7), dladm(8), flowstat(8), ifconfig(8), route(8)

The display of statistics by the show-flow subcommand, and the show-usage subcommand, have been removed. This functionality can now be accessed using the flowstat(8) utility.

February 5, 2022 OmniOS