linux.git/net/ethtool/netlink.c, branch v6.5

net: create device lookup API with reference tracking

2023-06-15T07:21:11+00:00

New users of dev_get_by_index() and dev_get_by_name() keep
getting added and it would be nice to steer them towards
the APIs with reference tracking.

Add variants of those calls which allocate the reference
tracker and use them in a couple of places.

Signed-off-by: Jakub Kicinski 
Reviewed-by: Eric Dumazet 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

net: ethtool: don't require empty header nests

2023-06-12T10:32:45+00:00

Ethtool currently requires a header nest (which is used to carry
the common family options) in all requests including dumps.

  $ cli.py --spec netlink/specs/ethtool.yaml --dump channels-get
  lib.ynl.NlError: Netlink error: Invalid argument
  nl_len = 64 (48) nl_flags = 0x300 nl_type = 2
	error: -22      extack: {'msg': 'request header missing'}

  $ cli.py --spec netlink/specs/ethtool.yaml --dump channels-get \
           --json '{"header":{}}';  )
  [{'combined-count': 1,
    'combined-max': 1,
    'header': {'dev-index': 2, 'dev-name': 'enp1s0'}}]

Requiring the header nest to always be there may seem nice
from the consistency perspective, but it's not serving any
practical purpose. We shouldn't burden the user like this.

Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

ethtool: netlink: convert commands to common SET

2023-01-27T12:24:32+00:00

Convert all SET commands where new common code is applicable.

Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

ethtool: netlink: handle SET intro/outro in the common code

2023-01-27T12:24:31+00:00

Most ethtool SET callbacks follow the same general structure.

  ethnl_parse_header_dev_get()
  rtnl_lock()
  ethnl_ops_begin()

  ... do stuff ...

  ethtool_notify()
  ethnl_ops_complete()
  rtnl_unlock()
  ethnl_parse_header_dev_put()

This leads to a lot of copy / pasted code an bugs when people
mis-handle the error path.

Add a generic implementation of this pattern with a .set callback
in struct ethnl_request_ops called to "do stuff".

Also add an optional .set_validate which is called before
ethnl_ops_begin() -- a lot of implementations do basic request
capability / sanity checking at that point.

Because we want to avoid generating the notification when
no change happened - adopt a slightly hairy return values:
 - 0 means nothing to do (no notification)
 - 1 means done / continue
 - negative error codes on error

Reuse .hdr_attr from struct ethnl_request_ops, GET and SET
use the same attr spaces in all cases.

Convert pause as an example (and to avoid unused function warnings).

Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

net: ethtool: add support for MAC Merge layer

2023-01-23T12:44:18+00:00

The MAC merge sublayer (IEEE 802.3-2018 clause 99) is one of 2
specifications (the other being Frame Preemption; IEEE 802.1Q-2018
clause 6.7.2), which work together to minimize latency caused by frame
interference at TX. The overall goal of TSN is for normal traffic and
traffic with a bounded deadline to be able to cohabitate on the same L2
network and not bother each other too much.

The standards achieve this (partly) by introducing the concept of
preemptible traffic, i.e. Ethernet frames that have a custom value for
the Start-of-Frame-Delimiter (SFD), and these frames can be fragmented
and reassembled at L2 on a link-local basis. The non-preemptible frames
are called express traffic, they are transmitted using a normal SFD, and
they can preempt preemptible frames, therefore having lower latency,
which can matter at lower (100 Mbps) link speeds, or at high MTUs (jumbo
frames around 9K). Preemption is not recursive, i.e. a P frame cannot
preempt another P frame. Preemption also does not depend upon priority,
or otherwise said, an E frame with prio 0 will still preempt a P frame
with prio 7.

In terms of implementation, the standards talk about the presence of an
express MAC (eMAC) which handles express traffic, and a preemptible MAC
(pMAC) which handles preemptible traffic, and these MACs are multiplexed
on the same MII by a MAC merge layer.

To support frame preemption, the definition of the SFD was generalized
to SMD (Start-of-mPacket-Delimiter), where an mPacket is essentially an
Ethernet frame fragment, or a complete frame. Stations unaware of an SMD
value different from the standard SFD will treat P frames as error
frames. To prevent that from happening, a negotiation process is
defined.

On RX, packets are dispatched to the eMAC or pMAC after being filtered
by their SMD. On TX, the eMAC/pMAC classification decision is taken by
the 802.1Q spec, based on packet priority (each of the 8 user priority
values may have an admin-status of preemptible or express).

The MAC Merge layer and the Frame Preemption parameters have some degree
of independence in terms of how software stacks are supposed to deal
with them. The activation of the MM layer is supposed to be controlled
by an LLDP daemon (after it has been communicated that the link partner
also supports it), after which a (hardware-based or not) verification
handshake takes place, before actually enabling the feature. So the
process is intended to be relatively plug-and-play. Whereas FP settings
are supposed to be coordinated across a network using something
approximating NETCONF.

The support contained here is exclusively for the 802.3 (MAC Merge)
portions and not for the 802.1Q (Frame Preemption) parts. This API is
sufficient for an LLDP daemon to do its job. The FP adminStatus variable
from 802.1Q is outside the scope of an LLDP daemon.

I have taken a few creative licenses and augmented the Linux kernel UAPI
compared to the standard managed objects recommended by IEEE 802.3.
These are:

- ETHTOOL_A_MM_PMAC_ENABLED: According to Figure 99-6: Receive
  Processing state diagram, a MAC Merge layer is always supposed to be
  able to receive P frames. However, this implies keeping the pMAC
  powered on, which will consume needless power in applications where FP
  will never be used. If LLDP is used, the reception of an Additional
  Ethernet Capabilities TLV from the link partner is sufficient
  indication that the pMAC should be enabled. So my proposal is that in
  Linux, we keep the pMAC turned off by default and that user space
  turns it on when needed.

- ETHTOOL_A_MM_VERIFY_ENABLED: The IEEE managed object is called
  aMACMergeVerifyDisableTx. I opted for consistency (positive logic) in
  the boolean netlink attributes offered, so this is also positive here.
  Other than the meaning being reversed, they correspond to the same
  thing.

- ETHTOOL_A_MM_MAX_VERIFY_TIME: I found it most reasonable for a LLDP
  daemon to maximize the verifyTime variable (delay between SMD-V
  transmissions), to maximize its chances that the LP replies. IEEE says
  that the verifyTime can range between 1 and 128 ms, but the NXP ENETC
  stupidly keeps this variable in a 7 bit register, so the maximum
  supported value is 127 ms. I could have chosen to hardcode this in the
  LLDP daemon to a lower value, but why not let the kernel expose its
  supported range directly.

- ETHTOOL_A_MM_TX_MIN_FRAG_SIZE: the standard managed object is called
  aMACMergeAddFragSize, and expresses the "additional" fragment size
  (on top of ETH_ZLEN), whereas this expresses the absolute value of the
  fragment size.

- ETHTOOL_A_MM_RX_MIN_FRAG_SIZE: there doesn't appear to exist a managed
  object mandated by the standard, but user space clearly needs to know
  what is the minimum supported fragment size of our local receiver,
  since LLDP must advertise a value no lower than that.

Signed-off-by: Vladimir Oltean 
Signed-off-by: David S. Miller

net/ethtool: add netlink interface for the PLCA RS

2023-01-11T08:35:02+00:00

Add support for configuring the PLCA Reconciliation Sublayer on
multi-drop PHYs that support IEEE802.3cg-2019 Clause 148 (e.g.,
10BASE-T1S). This patch adds the appropriate netlink interface
to ethtool.

Signed-off-by: Piergiorgio Beruto 
Reviewed-by: Andrew Lunn 
Signed-off-by: David S. Miller

ethtool: add netlink based get rss support

2022-12-06T01:25:00+00:00

Add netlink based support for "ethtool -x  [context x]"
command by implementing ETHTOOL_MSG_RSS_GET netlink message.
This is equivalent to functionality provided via ETHTOOL_GRSSH
in ioctl path. It sends RSS table, hash key and hash function
of an interface to user space.

This patch implements existing functionality available
in ioctl path and enables addition of new RSS context
based parameters in future.

Signed-off-by: Sudheer Mogilappagari 
Link: https://lore.kernel.org/r/20221202002555.241580-1-sudheer.mogilappagari@intel.com
Signed-off-by: Jakub Kicinski

ethtool: add interface to interact with Ethernet Power Equipment

2022-10-04T00:33:57+00:00

Add interface to support Power Sourcing Equipment. At current step it
provides generic way to address all variants of PSE devices as defined
in IEEE 802.3-2018 but support only objects specified for IEEE 802.3-2018 104.4
PoDL Power Sourcing Equipment (PSE).

Currently supported and mandatory objects are:
IEEE 802.3-2018 30.15.1.1.3 aPoDLPSEPowerDetectionStatus
IEEE 802.3-2018 30.15.1.1.2 aPoDLPSEAdminState
IEEE 802.3-2018 30.15.1.2.1 acPoDLPSEAdminControl

This is minimal interface needed to control PSE on each separate
ethernet port but it provides not all mandatory objects specified in
IEEE 802.3-2018.

Since "PoDL PSE" and "PSE" have similar names, but some different values
I decide to not merge them and keep separate naming schema. This should
allow as to be as close to IEEE 802.3 spec as possible and avoid name
conflicts in the future.

This implementation is connected to PHYs instead of MACs because PSE
auto classification can potentially interfere with PHY auto negotiation.
So, may be some extra PHY related initialization will be needed.

With WIP version of ethtools interaction with PSE capable link looks
as following:

$ ip l
...
5: t1l1@eth0:  ..
...

$ ethtool --show-pse t1l1
PSE attributs for t1l1:
PoDL PSE Admin State: disabled
PoDL PSE Power Detection Status: disabled

$ ethtool --set-pse t1l1 podl-pse-admin-control enable
$ ethtool --show-pse t1l1
PSE attributs for t1l1:
PoDL PSE Admin State: enabled
PoDL PSE Power Detection Status: delivering power

Signed-off-by: kernel test robot 
Signed-off-by: Oleksij Rempel 
Reviewed-by: Bagas Sanjaya 
Reviewed-by: Andrew Lunn 
Signed-off-by: Jakub Kicinski

ethtool: report missing header via ext_ack in the default handler

2022-08-30T10:20:43+00:00

The actual presence check for the header is in
ethnl_parse_header_dev_get() but it's a few layers in,
and already has a ton of arguments so let's just pick
the low hanging fruit and check for missing header in
the default request handler.

Reviewed-by: Ido Schimmel 
Reviewed-by: Johannes Berg 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Paolo Abeni

genetlink: start to validate reserved header bytes

2022-08-29T11:47:15+00:00

We had historically not checked that genlmsghdr.reserved
is 0 on input which prevents us from using those precious
bytes in the future.

One use case would be to extend the cmd field, which is
currently just 8 bits wide and 256 is not a lot of commands
for some core families.

To make sure that new families do the right thing by default
put the onus of opting out of validation on existing families.

Signed-off-by: Jakub Kicinski 
Acked-by: Paul Moore  (NetLabel)
Signed-off-by: David S. Miller