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linux/Documentation/netlink/specs/netdev.yaml
Daniel Borkmann 7789c6bb76 net: Add queue-create operation 
Add a ynl netdev family operation called queue-create that creates a
new queue on a netdevice:

      name: queue-create
      attribute-set: queue
      flags: [admin-perm]
      do:
        request:
          attributes:
            - ifindex
            - type
            - lease
        reply: &queue-create-op
          attributes:
            - id

This is a generic operation such that it can be extended for various
use cases in future. Right now it is mandatory to specify ifindex,
the queue type which is enforced to rx and a lease. The newly created
queue id is returned to the caller.

A queue from a virtual device can have a lease which refers to another
queue from a physical device. This is useful for memory providers
and AF_XDP operations which take an ifindex and queue id to allow
applications to bind against virtual devices in containers. The lease
couples both queues together and allows to proxy the operations from
a virtual device in a container to the physical device.

In future, the nested lease attribute can be lifted and made optional
for other use-cases such as dynamic queue creation for physical
netdevs. The lack of lease and the specification of the physical
device as an ifindex will imply that we need a real queue to be
allocated. Similarly, the queue type enforcement to rx can then be
lifted as well to support tx.

An early implementation had only driver-specific integration [0], but
in order for other virtual devices to reuse, it makes sense to have
this as a generic API in core net.

For leasing queues, the virtual netdev must have real_num_rx_queues
less than num_rx_queues at the time of calling queue-create. The
queue-type must be rx as only rx queues are supported for leasing
for now. We also enforce that the queue-create ifindex must point
to a virtual device, and that the nested lease attribute's ifindex
must point to a physical device. The nested lease attribute set
contains a netns-id attribute which is optional and can specify a
netns-id relative to the caller's netns. It requires cap_net_admin
and if the netns-id attribute is not specified, the lease ifindex
will be retrieved from the current netns. Also, it is modeled as
an s32 type similarly as done elsewhere in the stack.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://bpfconf.ebpf.io/bpfconf2025/bpfconf2025_material/lsfmmbpf_2025_netkit_borkmann.pdf [0]
Link: https://patch.msgid.link/20260402231031.447597-2-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-09 18:21:45 -07:00

857 lines
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# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
---
name: netdev
doc: >-
netdev configuration over generic netlink.
definitions:
-
type: flags
name: xdp-act
render-max: true
entries:
-
name: basic
doc: >-
XDP features set supported by all drivers
(XDP_ABORTED, XDP_DROP, XDP_PASS, XDP_TX)
-
name: redirect
doc: >-
The netdev supports XDP_REDIRECT
-
name: ndo-xmit
doc: >-
This feature informs if netdev implements ndo_xdp_xmit callback.
-
name: xsk-zerocopy
doc: >-
This feature informs if netdev supports AF_XDP in zero copy mode.
-
name: hw-offload
doc: >-
This feature informs if netdev supports XDP hw offloading.
-
name: rx-sg
doc: >-
This feature informs if netdev implements non-linear XDP buffer
support in the driver napi callback.
-
name: ndo-xmit-sg
doc: >-
This feature informs if netdev implements non-linear XDP buffer
support in ndo_xdp_xmit callback.
-
type: flags
name: xdp-rx-metadata
entries:
-
name: timestamp
doc: |
Device is capable of exposing receive HW timestamp via
bpf_xdp_metadata_rx_timestamp().
-
name: hash
doc: |
Device is capable of exposing receive packet hash via
bpf_xdp_metadata_rx_hash().
-
name: vlan-tag
doc: |
Device is capable of exposing receive packet VLAN tag via
bpf_xdp_metadata_rx_vlan_tag().
-
type: flags
name: xsk-flags
entries:
-
name: tx-timestamp
doc: >-
HW timestamping egress packets is supported by the driver.
-
name: tx-checksum
doc: >-
L3 checksum HW offload is supported by the driver.
-
name: tx-launch-time-fifo
doc: >-
Launch time HW offload is supported by the driver.
-
name: queue-type
type: enum
entries: [rx, tx]
-
name: qstats-scope
type: flags
entries: [queue]
-
name: napi-threaded
type: enum
entries: [disabled, enabled, busy-poll]
attribute-sets:
-
name: dev
attributes:
-
name: ifindex
doc: netdev ifindex
type: u32
checks:
min: 1
-
name: pad
type: pad
-
name: xdp-features
doc: Bitmask of enabled xdp-features.
type: u64
enum: xdp-act
-
name: xdp-zc-max-segs
doc: max fragment count supported by ZC driver
type: u32
checks:
min: 1
-
name: xdp-rx-metadata-features
doc: Bitmask of supported XDP receive metadata features.
See Documentation/networking/xdp-rx-metadata.rst for more details.
type: u64
enum: xdp-rx-metadata
-
name: xsk-features
doc: Bitmask of enabled AF_XDP features.
type: u64
enum: xsk-flags
-
name: io-uring-provider-info
attributes: []
-
name: page-pool
attributes:
-
name: id
doc: Unique ID of a Page Pool instance.
type: uint
checks:
min: 1
max: u32-max
-
name: ifindex
doc: |
ifindex of the netdev to which the pool belongs.
May not be reported if the page pool was allocated for a netdev
which got destroyed already (page pools may outlast their netdevs
because they wait for all memory to be returned).
type: u32
checks:
min: 1
max: s32-max
-
name: napi-id
doc: Id of NAPI using this Page Pool instance.
type: uint
checks:
min: 1
max: u32-max
-
name: inflight
type: uint
doc: |
Number of outstanding references to this page pool (allocated
but yet to be freed pages). Allocated pages may be held in
socket receive queues, driver receive ring, page pool recycling
ring, the page pool cache, etc.
-
name: inflight-mem
type: uint
doc: |
Amount of memory held by inflight pages.
-
name: detach-time
type: uint
doc: |
Seconds in CLOCK_BOOTTIME of when Page Pool was detached by
the driver. Once detached Page Pool can no longer be used to
allocate memory.
Page Pools wait for all the memory allocated from them to be freed
before truly disappearing. "Detached" Page Pools cannot be
"re-attached", they are just waiting to disappear.
Attribute is absent if Page Pool has not been detached, and
can still be used to allocate new memory.
-
name: dmabuf
doc: ID of the dmabuf this page-pool is attached to.
type: u32
-
name: io-uring
doc: io-uring memory provider information.
type: nest
nested-attributes: io-uring-provider-info
-
name: page-pool-info
subset-of: page-pool
attributes:
-
name: id
-
name: ifindex
-
name: page-pool-stats
doc: |
Page pool statistics, see docs for struct page_pool_stats
for information about individual statistics.
attributes:
-
name: info
doc: Page pool identifying information.
type: nest
nested-attributes: page-pool-info
-
name: alloc-fast
type: uint
value: 8 # reserve some attr ids in case we need more metadata later
-
name: alloc-slow
type: uint
-
name: alloc-slow-high-order
type: uint
-
name: alloc-empty
type: uint
-
name: alloc-refill
type: uint
-
name: alloc-waive
type: uint
-
name: recycle-cached
type: uint
-
name: recycle-cache-full
type: uint
-
name: recycle-ring
type: uint
-
name: recycle-ring-full
type: uint
-
name: recycle-released-refcnt
type: uint
-
name: napi
attributes:
-
name: ifindex
doc: ifindex of the netdevice to which NAPI instance belongs.
type: u32
checks:
min: 1
-
name: id
doc: ID of the NAPI instance.
type: u32
-
name: irq
doc: The associated interrupt vector number for the napi
type: u32
-
name: pid
doc: PID of the napi thread, if NAPI is configured to operate in
threaded mode. If NAPI is not in threaded mode (i.e. uses normal
softirq context), the attribute will be absent.
type: u32
-
name: defer-hard-irqs
doc: The number of consecutive empty polls before IRQ deferral ends
and hardware IRQs are re-enabled.
type: u32
checks:
max: s32-max
-
name: gro-flush-timeout
doc: The timeout, in nanoseconds, of when to trigger the NAPI watchdog
timer which schedules NAPI processing. Additionally, a non-zero
value will also prevent GRO from flushing recent super-frames at
the end of a NAPI cycle. This may add receive latency in exchange
for reducing the number of frames processed by the network stack.
type: uint
-
name: irq-suspend-timeout
doc: The timeout, in nanoseconds, of how long to suspend irq
processing, if event polling finds events
type: uint
-
name: threaded
doc: Whether the NAPI is configured to operate in threaded polling
mode. If this is set to enabled then the NAPI context operates
in threaded polling mode. If this is set to busy-poll, then the
threaded polling mode also busy polls.
type: u32
enum: napi-threaded
-
name: xsk-info
attributes: []
-
name: queue
attributes:
-
name: id
doc: Queue index; most queue types are indexed like a C array, with
indexes starting at 0 and ending at queue count - 1. Queue indexes
are scoped to an interface and queue type.
type: u32
-
name: ifindex
doc: ifindex of the netdevice to which the queue belongs.
type: u32
checks:
min: 1
-
name: type
doc: Queue type as rx, tx. Each queue type defines a separate ID space.
XDP TX queues allocated in the kernel are not linked to NAPIs and
thus not listed. AF_XDP queues will have more information set in
the xsk attribute.
type: u32
enum: queue-type
-
name: napi-id
doc: ID of the NAPI instance which services this queue.
type: u32
-
name: dmabuf
doc: ID of the dmabuf attached to this queue, if any.
type: u32
-
name: io-uring
doc: io_uring memory provider information.
type: nest
nested-attributes: io-uring-provider-info
-
name: xsk
doc: XSK information for this queue, if any.
type: nest
nested-attributes: xsk-info
-
name: lease
doc: |
A queue from a virtual device can have a lease which refers to
another queue from a physical device. This is useful for memory
providers and AF_XDP operations which take an ifindex and queue id
to allow applications to bind against virtual devices in containers.
type: nest
nested-attributes: lease
-
name: qstats
doc: |
Get device statistics, scoped to a device or a queue.
These statistics extend (and partially duplicate) statistics available
in struct rtnl_link_stats64.
Value of the `scope` attribute determines how statistics are
aggregated. When aggregated for the entire device the statistics
represent the total number of events since last explicit reset of
the device (i.e. not a reconfiguration like changing queue count).
When reported per-queue, however, the statistics may not add
up to the total number of events, will only be reported for currently
active objects, and will likely report the number of events since last
reconfiguration.
attributes:
-
name: ifindex
doc: ifindex of the netdevice to which stats belong.
type: u32
checks:
min: 1
-
name: queue-type
doc: Queue type as rx, tx, for queue-id.
type: u32
enum: queue-type
-
name: queue-id
doc: Queue ID, if stats are scoped to a single queue instance.
type: u32
-
name: scope
doc: |
What object type should be used to iterate over the stats.
type: uint
enum: qstats-scope
-
name: rx-packets
doc: |
Number of wire packets successfully received and passed to the stack.
For drivers supporting XDP, XDP is considered the first layer
of the stack, so packets consumed by XDP are still counted here.
type: uint
value: 8 # reserve some attr ids in case we need more metadata later
-
name: rx-bytes
doc: Successfully received bytes, see `rx-packets`.
type: uint
-
name: tx-packets
doc: |
Number of wire packets successfully sent. Packet is considered to be
successfully sent once it is in device memory (usually this means
the device has issued a DMA completion for the packet).
type: uint
-
name: tx-bytes
doc: Successfully sent bytes, see `tx-packets`.
type: uint
-
name: rx-alloc-fail
doc: |
Number of times skb or buffer allocation failed on the Rx datapath.
Allocation failure may, or may not result in a packet drop, depending
on driver implementation and whether system recovers quickly.
type: uint
-
name: rx-hw-drops
doc: |
Number of all packets which entered the device, but never left it,
including but not limited to: packets dropped due to lack of buffer
space, processing errors, explicit or implicit policies and packet
filters.
type: uint
-
name: rx-hw-drop-overruns
doc: |
Number of packets dropped due to transient lack of resources, such as
buffer space, host descriptors etc.
type: uint
-
name: rx-csum-complete
doc: Number of packets that were marked as CHECKSUM_COMPLETE.
type: uint
-
name: rx-csum-unnecessary
doc: Number of packets that were marked as CHECKSUM_UNNECESSARY.
type: uint
-
name: rx-csum-none
doc: Number of packets that were not checksummed by device.
type: uint
-
name: rx-csum-bad
doc: |
Number of packets with bad checksum. The packets are not discarded,
but still delivered to the stack.
type: uint
-
name: rx-hw-gro-packets
doc: |
Number of packets that were coalesced from smaller packets by the
device. Counts only packets coalesced with the HW-GRO netdevice
feature, LRO-coalesced packets are not counted.
type: uint
-
name: rx-hw-gro-bytes
doc: See `rx-hw-gro-packets`.
type: uint
-
name: rx-hw-gro-wire-packets
doc: |
Number of packets that were coalesced to bigger packetss with the
HW-GRO netdevice feature. LRO-coalesced packets are not counted.
type: uint
-
name: rx-hw-gro-wire-bytes
doc: See `rx-hw-gro-wire-packets`.
type: uint
-
name: rx-hw-drop-ratelimits
doc: |
Number of the packets dropped by the device due to the received
packets bitrate exceeding the device rate limit.
type: uint
-
name: tx-hw-drops
doc: |
Number of packets that arrived at the device but never left it,
encompassing packets dropped for reasons such as processing errors, as
well as those affected by explicitly defined policies and packet
filtering criteria.
type: uint
-
name: tx-hw-drop-errors
doc: Number of packets dropped because they were invalid or malformed.
type: uint
-
name: tx-csum-none
doc: |
Number of packets that did not require the device to calculate the
checksum.
type: uint
-
name: tx-needs-csum
doc: |
Number of packets that required the device to calculate the checksum.
This counter includes the number of GSO wire packets for which device
calculated the L4 checksum.
type: uint
-
name: tx-hw-gso-packets
doc: |
Number of packets that necessitated segmentation into smaller packets
by the device.
type: uint
-
name: tx-hw-gso-bytes
doc: See `tx-hw-gso-packets`.
type: uint
-
name: tx-hw-gso-wire-packets
doc: |
Number of wire-sized packets generated by processing
`tx-hw-gso-packets`
type: uint
-
name: tx-hw-gso-wire-bytes
doc: See `tx-hw-gso-wire-packets`.
type: uint
-
name: tx-hw-drop-ratelimits
doc: |
Number of the packets dropped by the device due to the transmit
packets bitrate exceeding the device rate limit.
type: uint
-
name: tx-stop
doc: |
Number of times driver paused accepting new tx packets
from the stack to this queue, because the queue was full.
Note that if BQL is supported and enabled on the device
the networking stack will avoid queuing a lot of data at once.
type: uint
-
name: tx-wake
doc: |
Number of times driver re-started accepting send
requests to this queue from the stack.
type: uint
-
name: queue-id
subset-of: queue
attributes:
-
name: id
-
name: type
-
name: lease
attributes:
-
name: ifindex
doc: The netdev ifindex to lease the queue from.
type: u32
checks:
min: 1
-
name: queue
doc: The netdev queue to lease from.
type: nest
nested-attributes: queue-id
-
name: netns-id
doc: The network namespace id of the netdev.
type: s32
checks:
min: 0
-
name: dmabuf
attributes:
-
name: ifindex
doc: netdev ifindex to bind the dmabuf to.
type: u32
checks:
min: 1
-
name: queues
doc: receive queues to bind the dmabuf to.
type: nest
nested-attributes: queue-id
multi-attr: true
-
name: fd
doc: dmabuf file descriptor to bind.
type: u32
-
name: id
doc: id of the dmabuf binding
type: u32
checks:
min: 1
operations:
list:
-
name: dev-get
doc: Get / dump information about a netdev.
attribute-set: dev
do:
request:
attributes:
- ifindex
reply: &dev-all
attributes:
- ifindex
- xdp-features
- xdp-zc-max-segs
- xdp-rx-metadata-features
- xsk-features
dump:
reply: *dev-all
-
name: dev-add-ntf
doc: Notification about device appearing.
notify: dev-get
mcgrp: mgmt
-
name: dev-del-ntf
doc: Notification about device disappearing.
notify: dev-get
mcgrp: mgmt
-
name: dev-change-ntf
doc: Notification about device configuration being changed.
notify: dev-get
mcgrp: mgmt
-
name: page-pool-get
doc: |
Get / dump information about Page Pools.
Only Page Pools associated by the driver with a net_device
can be listed. ifindex will not be reported if the net_device
no longer exists.
attribute-set: page-pool
do:
request:
attributes:
- id
reply: &pp-reply
attributes:
- id
- ifindex
- napi-id
- inflight
- inflight-mem
- detach-time
- dmabuf
- io-uring
dump:
reply: *pp-reply
config-cond: page-pool
-
name: page-pool-add-ntf
doc: Notification about page pool appearing.
notify: page-pool-get
mcgrp: page-pool
config-cond: page-pool
-
name: page-pool-del-ntf
doc: Notification about page pool disappearing.
notify: page-pool-get
mcgrp: page-pool
config-cond: page-pool
-
name: page-pool-change-ntf
doc: Notification about page pool configuration being changed.
notify: page-pool-get
mcgrp: page-pool
config-cond: page-pool
-
name: page-pool-stats-get
doc: Get page pool statistics.
attribute-set: page-pool-stats
do:
request:
attributes:
- info
reply: &pp-stats-reply
attributes:
- info
- alloc-fast
- alloc-slow
- alloc-slow-high-order
- alloc-empty
- alloc-refill
- alloc-waive
- recycle-cached
- recycle-cache-full
- recycle-ring
- recycle-ring-full
- recycle-released-refcnt
dump:
reply: *pp-stats-reply
config-cond: page-pool-stats
-
name: queue-get
doc: Get queue information from the kernel.
Only configured queues will be reported (as opposed to all available
hardware queues).
attribute-set: queue
do:
request:
attributes:
- ifindex
- type
- id
reply: &queue-get-op
attributes:
- id
- type
- napi-id
- ifindex
- dmabuf
- io-uring
- xsk
- lease
dump:
request:
attributes:
- ifindex
reply: *queue-get-op
-
name: napi-get
doc: Get information about NAPI instances configured on the system.
attribute-set: napi
do:
request:
attributes:
- id
reply: &napi-get-op
attributes:
- id
- ifindex
- irq
- pid
- defer-hard-irqs
- gro-flush-timeout
- irq-suspend-timeout
- threaded
dump:
request:
attributes:
- ifindex
reply: *napi-get-op
-
name: qstats-get
doc: |
Get / dump fine grained statistics. Which statistics are reported
depends on the device and the driver, and whether the driver stores
software counters per-queue.
attribute-set: qstats
dump:
request:
attributes:
- ifindex
- scope
reply:
attributes:
- ifindex
- queue-type
- queue-id
- rx-packets
- rx-bytes
- tx-packets
- tx-bytes
- rx-alloc-fail
- rx-hw-drops
- rx-hw-drop-overruns
- rx-csum-complete
- rx-csum-unnecessary
- rx-csum-none
- rx-csum-bad
- rx-hw-gro-packets
- rx-hw-gro-bytes
- rx-hw-gro-wire-packets
- rx-hw-gro-wire-bytes
- rx-hw-drop-ratelimits
- tx-hw-drops
- tx-hw-drop-errors
- tx-csum-none
- tx-needs-csum
- tx-hw-gso-packets
- tx-hw-gso-bytes
- tx-hw-gso-wire-packets
- tx-hw-gso-wire-bytes
- tx-hw-drop-ratelimits
- tx-stop
- tx-wake
-
name: bind-rx
doc: Bind dmabuf to netdev
attribute-set: dmabuf
flags: [admin-perm]
do:
request:
attributes:
- ifindex
- fd
- queues
reply:
attributes:
- id
-
name: napi-set
doc: Set configurable NAPI instance settings.
attribute-set: napi
flags: [admin-perm]
do:
request:
attributes:
- id
- defer-hard-irqs
- gro-flush-timeout
- irq-suspend-timeout
- threaded
-
name: bind-tx
doc: Bind dmabuf to netdev for TX
attribute-set: dmabuf
do:
request:
attributes:
- ifindex
- fd
reply:
attributes:
- id
-
name: queue-create
doc: |
Create a new queue for the given netdevice. Whether this operation
is supported depends on the device and the driver.
attribute-set: queue
flags: [admin-perm]
do:
request:
attributes:
- ifindex
- type
- lease
reply: &queue-create-op
attributes:
- id
kernel-family:
headers: ["net/netdev_netlink.h"]
sock-priv: struct netdev_nl_sock
mcast-groups:
list:
-
name: mgmt
-
name: page-pool
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