Add the driver's data path. Tx handles skbs, XDP, and kTLS, Rx has skbs
and XDP. Also included are Rx and Tx queue creation/tear-down and
tracing.
Signed-off-by: Dimitris Michailidis <dmichail@fungible.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The devlink part, which is minimal at this time giving just the driver
name.
Signed-off-by: Dimitris Michailidis <dmichail@fungible.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add ethtool operations, primarily related to queues and ports, as well
as device statistics.
Signed-off-by: Dimitris Michailidis <dmichail@fungible.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is the first part of the Fungible ethernet driver. It deals with
device probing, net_device creation, and netdev ops.
Signed-off-by: Dimitris Michailidis <dmichail@fungible.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fungible cards have a number of different PCI functions and thus
different drivers, all of which use a common method to initialize and
interact with the device. This commit adds a library module that
collects these common mechanisms. They mainly deal with device
initialization, setting up and destroying queues, and operating an admin
queue. A subset of the FW interface is also included here.
Signed-off-by: Dimitris Michailidis <dmichail@fungible.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Dimitris Michailidis <dmichail@fungible.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Menglong Dong says:

====================
net: use kfree_skb_reason() for ip/neighbour

In the series "net: use kfree_skb_reason() for ip/udp packet receive",
reasons for skb drops are added to the packet receive process of IP
layer. Link:

https://lore.kernel.org/netdev/20220205074739.543606-1-imagedong@tencent.com/

And in the first patch of this series, skb drop reasons are added to
the packet egress path of IP layer. As kfree_skb() is not used frequent,
I commit these changes at once and didn't create a patch for every
functions that involed. Following functions are handled:

__ip_queue_xmit()
ip_finish_output()
ip_mc_finish_output()
ip6_output()
ip6_finish_output()
ip6_finish_output2()

Following new drop reasons are introduced (what they mean can be seen
in the document of them):

SKB_DROP_REASON_IP_OUTNOROUTES
SKB_DROP_REASON_BPF_CGROUP_EGRESS
SKB_DROP_REASON_IPV6DISABLED
SKB_DROP_REASON_NEIGH_CREATEFAIL

In the 2th and 3th patches, kfree_skb_reason() is used in neighbour
subsystem instead of kfree_skb(). __neigh_event_send() and
arp_error_report() are involed, and following new drop reasons are
introduced:

SKB_DROP_REASON_NEIGH_FAILED
SKB_DROP_REASON_NEIGH_QUEUEFULL
SKB_DROP_REASON_NEIGH_DEAD

Changes since v2:
- fix typo in the 1th patch of 'SKB_DROP_REASON_IPV6DSIABLED' reported
  by Roman

Changes since v1:
- introduce SKB_DROP_REASON_NEIGH_CREATEFAIL for some path in the 1th
  patch
- introduce SKB_DROP_REASON_NEIGH_DEAD in the 2th patch
- simplify the document for the new drop reasons, as David Ahern
  suggested
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

When neighbour become invalid or destroyed, neigh_invalidate() will be
called. neigh->ops->error_report() will be called if the neighbour's
state is NUD_FAILED, and seems here is the only use of error_report().
So we can tell that the reason of skb drops in arp_error_report() is
SKB_DROP_REASON_NEIGH_FAILED.

Replace kfree_skb() used in arp_error_report() with kfree_skb_reason().
Reviewed-by: Mengen Sun <mengensun@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Replace kfree_skb() used in __neigh_event_send() with
kfree_skb_reason(). Following drop reasons are added:

SKB_DROP_REASON_NEIGH_FAILED
SKB_DROP_REASON_NEIGH_QUEUEFULL
SKB_DROP_REASON_NEIGH_DEAD

The first two reasons above should be the hot path that skb drops
in neighbour subsystem.
Reviewed-by: Mengen Sun <mengensun@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Replace kfree_skb() which is used in the packet egress path of IP layer
with kfree_skb_reason(). Functions that are involved include:

__ip_queue_xmit()
ip_finish_output()
ip_mc_finish_output()
ip6_output()
ip6_finish_output()
ip6_finish_output2()

Following new drop reasons are introduced:

SKB_DROP_REASON_IP_OUTNOROUTES
SKB_DROP_REASON_BPF_CGROUP_EGRESS
SKB_DROP_REASON_IPV6DISABLED
SKB_DROP_REASON_NEIGH_CREATEFAIL
Reviewed-by: Mengen Sun <mengensun@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Russell King says:

====================
net: dsa: ocelot: phylink updates

This series updates the Ocelot DSA driver for some of the recent
phylink changes. Specifically, we fill in the supported_interfaces
fields, convert to mac_select_pcs and mark the driver as non-legacy.
We do not convert to phylink_generic_validate() as Ocelot has
special support for its rate adapting PCS which makes the generic
validate method unsuitable for this driver.

The three changes mentioned above are implemented in their own
separate patches with one additional cleanup:

1) Populate the supported_interfaces bitmap
2) Remove the now unnecessary interface checks in the validate methods
3) Convert from phylink_set_pcs() to .mac_select_pcs.
4) Mark the driver as non-legacy

Thanks.

RFC -> non-RFC: add reviewed-by/tested-by's, update patch 1 to set the
supported_interfaces bitmap in felix.c rather than the sub-drivers as
requested by Vladimir.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The ocelot DSA driver does not make use of the speed, duplex, pause or
advertisement in its phylink_mac_config() implementation, so it can be
marked as a non-legacy driver.
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Convert the PCS selection to use mac_select_pcs, which allows the PCS
to perform any validation it needs, and removes the need to set the PCS
in the mac_config() callback, delving into the higher DSA levels to do
so.
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the supported interfaces bitmap is populated, phylink will itself
check that the interface mode is present in this bitmap. Drivers no
longer need to perform this check themselves. Remove these checks.
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Populate the supported interfaces bitmap for the Ocelot DSA switches.

Since all sub-drivers only support a single interface mode, defined by
ocelot_port->phy_mode, we can handle this in the main driver code
without reference to the sub-driver.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Matt Johnston says:

====================
Small fixes for MCTP

This series has 3 fixes for MCTP.
====================

Link: https://lore.kernel.org/r/20220225053938.643605-1-matt@codeconstruct.com.auSigned-off-by: Jakub Kicinski <kuba@kernel.org>

We should be testing the length before fitting into the u8 byte_count.
This is just a sanity check, the MCTP stack should have limited to MTU
which is checked, and we check consistency later in mctp_i2c_xmit().

Found by Smatch
mctp_i2c_header_create() warn: impossible condition
    '(hdr->byte_count > 255) => (0-255 > 255)'
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The skb is handed off to netif_rx() which may free it.
Found by Smatch.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Previously if an unregister notify handler ran twice (waiting for
netdev to be released) it would print a warning in mctp_unregister()
every subsequent time the unregister notify occured.

Instead we only need to worry about the case where a mctp_ptr is
set on an unknown device type.
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Intel AlderLake-S platform is capable of running on 2.5GBps link speed.

This patch enables 2.5Gbps link speed on AlderLake-S platform.
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Link: https://lore.kernel.org/r/20220225023325.474242-1-vee.khee.wong@linux.intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Currently an invalid port throws a WARN_ON warning however invalid
uninitialized values in reg and cpu_port_index are being used later
on. Fix this by returning -EINVAL for an invalid port value.

Addresses clang-scan warnings:
drivers/net/dsa/qca8k.c:1981:3: warning: 2nd function call argument is an
  uninitialized value [core.CallAndMessage]
drivers/net/dsa/qca8k.c:1999:9: warning: 2nd function call argument is an
  uninitialized value [core.CallAndMessage]

Fixes: 7544b3ff ("net: dsa: qca8k: move pcs configuration")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220224220557.147075-1-colin.i.king@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Russell King says:

====================
net: dsa: sja1105: phylink updates

This series updates the phylink implementation in sja1105 to use the
supported_interfaces bitmap, convert to the mac_select_pcs() interface,
mark as non-legacy, and get rid of the validation method.

As a final step, enable switching between SGMII and 2500BASE-X as it
is a feature that Vladimir desires.

Specifically, the patches in this series:

1. Populates the supported_interfaces bitmap.
2. As a result of the supported_interfaces bitmap being populated,
   sja1105 no longer needs to check the interface mode as phylink
   will do this.
3. Switch away from using phylink_set_pcs(), using the mac_select_pcs()
   method instead.
4. Mark the driver as not-legacy
5. Fill in mac_capabilities using _exactly_ the same conditions as is
   currently used to decide which link modes to support, and convert
   to use phylink_generic_validate()
6. Add brand new support to permit switching between SGMII and
   2500BASE-X modes of operation as per Vladimir's single patch that
   performs steps 1, 2, 5 and 6 in one go.

There are some additional changes in Vladimir's single patch that I
have not included:

* validation of priv->phy_mode[] in sja1105_phylink_get_caps(). The
  driver has already validated the phy_mode for each port in
  sja1105_init_mii_settings(), and a failure here will prevent the
  driver reaching sja1105_phylink_get_caps().

* Changing the decisions on which mac_capabilities to set. Vladimir's
  patch always sets MAC_10FD | MAC_100FD | MAC_1000FD despite the
  current code clearly making the 1G speed conditional on the
  xmii_mode for the port. The change in decision making may be
  visible when in PHY_INTERFACE_MODE_INTERNAL mode, for which
  the phylink_generic_validate() will pass through all the MAC
  capabilities as ethtool link modes.

  Hence, if we have PHY_INTERFACE_MODE_INTERNAL but supports_rgmii[]
  or supports_sgmii[] is non-zero, currently we do not get 1G speeds.
  With Vladimir's additional change, we will get 1G speeds.

  While it is not clear whether that can happen, I feel changing the
  decision making should be a separate patch.

* The decision for MAC_2500FD is made differently -
  sja1105_init_mii_settings() allows PHY_INTERFACE_MODE_2500BASEX
  when supports_2500basex[] is non-zero, and is not based on any other
  condition such as supports_sgmii[] or supports_rgmii[]. Vladimir's
  patch makes it additionally conditional on those supports_.gmii[]
  settings, which is a functional change that should be made in a
  separate patch - and if desired, then sja1105_init_mii_settings()
  should also be updated at the same time.

Consequently, I believe that my previous objections to Vladimir's
single patch approach are well founded and justified, even through
Vladimir is the maintainer of this driver. I have no objection to
the additional changes, I just don't think they should all be wrapped
up into a single patch that converts the way validation is done _and_
also makes a bunch of other functional changes.

RFC->non-RFC: added Vladimir's Reviewed-by's, fixed the typo in the
commit message of patch 6, and removed the phrase at the end of a
comment as requested.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Vladimir Oltean suggests that sja1105 can support switching between
SGMII and 2500BASE-X modes. Augment sja1105_phylink_get_caps() to
fill in both interface modes if they can be supported.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Populate the MAC capabilities for the SJA1105 DSA switch using the same
decision making which sja1105_phylink_validate() uses. Remove the now
obsolete sja1105_phylink_validate() implementation to allow DSA to use
phylink_generic_validate() for this switch driver.

As noted by Vladimir, this fixes an inconsequential bug which allowed
gigabit and lower interface modes to be indicated when operating in
2500base-X mode.
Reviewed-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;                                Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

The sja1105 DSA driver does not have a phylink_mac_config() method
implementation, it is safe to mark this as a non-legacy driver.
Reviewed-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;                                Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Convert the PCS selection to use mac_select_pcs, which allows the PCS
to perform any validation it needs, and removes the need to set the PCS
in the mac_config() callback, delving into the higher DSA levels to do
so.
Reviewed-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;                                Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the supported interfaces bitmap is populated, phylink will itself
check that the interface mode is present in this bitmap. Drivers no
longer need to perform this check themselves. Remove these checks.
Reviewed-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;                                Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Populate the supported interfaces bitmap for the SJA1105 DSA switch.

This switch only supports a static model of configuration, so we
restrict the interface modes to the configured setting.
Reviewed-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;                                Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: Vladimir Oltean <vladimir.    │
Signed-off-by: David S. Miller <davem@davemloft.net>

This change adds a new OpenFlow field OFPXMT_OFB_IPV6_EXTHDR and
packets can be filtered using ipv6_ext flag.
Signed-off-by: Toms Atteka <cpp.code.lv@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Simon Horman says:

====================
nfp: flow-independent tc action hardware offload

Baowen Zheng says:

Allow nfp NIC to offload tc actions independent of flows.

The motivation for this work is to offload tc actions independent of flows
for nfp NIC. We allow nfp driver to provide hardware offload of OVS
metering feature - which calls for policers that may be used by multiple
flows and whose lifecycle is independent of any flows that use them.

When nfp driver tries to offload a flow table using the independent action,
the driver will search if the action is already offloaded to the hardware.
If not, the flow table offload will fail.

When the nfp NIC successes to offload an action, the user can check
in_hw_count when dumping the tc action.

Tc cli command to offload and dump an action:

 # tc actions add action police rate 100mbit burst 10000k index 200 skip_sw

 # tc -s -d actions list action police

 total acts 1

      action order 0:  police 0xc8 rate 100Mbit burst 10000Kb mtu 2Kb action reclassify
      overhead 0b linklayer ethernet
      ref 1 bind 0  installed 142 sec used 0 sec
      Action statistics:
      Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
      backlog 0b 0p requeues 0
      skip_sw in_hw in_hw_count 1
      used_hw_stats delayed
====================

Link: https://lore.kernel.org/r/20220223162302.97609-1-simon.horman@corigine.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Add NFP_FL_FEATS_QOS_METER to host features to enable meter
offload in driver.

Before adding this feature, we will not offload any police action
since we will check the host features before offloading any police
action.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Offload flow table if the action is already offloaded to hardware when
flow table uses this action.

Change meter id to type of u32 to support all the action index.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Add a process to update action stats from hardware.

This stats data will be updated to tc action when dumping actions
or filters.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Add a hash table to store meter table.

This meter table will also be used by flower action.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Add process to offload tc action to hardware.

Currently we only support to offload police action.

Add meter capability to check if firmware supports
meter offload.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Add an policer API to support ingress/egress meter.

Change ingress police to compatible with the new API.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The functions do essentially the same work to verify TCP-MD5 sign.
Code can be merged into one family-independent function in order to
reduce copy'n'paste and generated code.
Later with TCP-AO option added, this will allow to create one function
that's responsible for segment verification, that will have all the
different checks for MD5/AO/non-signed packets, which in turn will help
to see checks for all corner-cases in one function, rather than spread
around different families and functions.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220223175740.452397-1-dima@arista.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Vladimir Oltean says:

====================
FDB entries on DSA LAG interfaces

This work permits having static and local FDB entries on LAG interfaces
that are offloaded by DSA ports. New API needs to be introduced in
drivers. To maintain consistency with the bridging offload code, I've
taken the liberty to reorganize the data structures added by Tobias in
the DSA core a little bit.

Tested on NXP LS1028A (felix switch). Would appreciate feedback/testing
on other platforms too. Testing procedure was the one described here:
https://patchwork.kernel.org/project/netdevbpf/cover/20210205130240.4072854-1-vladimir.oltean@nxp.com/

with this script:

ip link del bond0
ip link add bond0 type bond mode 802.3ad
ip link set swp1 down && ip link set swp1 master bond0 && ip link set swp1 up
ip link set swp2 down && ip link set swp2 master bond0 && ip link set swp2 up
ip link del br0
ip link add br0 type bridge && ip link set br0 up
ip link set br0 arp off
ip link set bond0 master br0 && ip link set bond0 up
ip link set swp0 master br0 && ip link set swp0 up
ip link set dev bond0 type bridge_slave flood off learning off
bridge fdb add dev bond0 <mac address of other eno0> master static

I'm noticing a problem in 'bridge fdb dump' with the 'self' entries, and
I didn't solve this. On Ocelot, an entry learned on a LAG is reported as
being on the first member port of it (so instead of saying 'self bond0',
it says 'self swp1'). This is better than not seeing the entry at all,
but when DSA queries for the FDBs on a port via ds->ops->port_fdb_dump,
it never queries for FDBs on a LAG. Not clear what we should do there,
we aren't in control of the ->ndo_fdb_dump of the bonding/team drivers.
Alternatively, we could just consider the 'self' entries reported via
ndo_fdb_dump as "better than nothing", and concentrate on the 'master'
entries that are in sync with the bridge when packets are flooded to
software.
====================

Link: https://lore.kernel.org/r/20220223140054.3379617-1-vladimir.oltean@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This adds the logic in the Felix DSA driver and Ocelot switch library.
For Ocelot switches, the DEST_IDX that is the output of the MAC table
lookup is a logical port (equal to physical port, if no LAG is used, or
a dynamically allocated number otherwise). The allocation we have in
place for LAG IDs is different from DSA's, so we can't use that:
- DSA allocates a continuous range of LAG IDs starting from 1
- Ocelot appears to require that physical ports and LAG IDs are in the
  same space of [0, num_phys_ports), and additionally, ports that aren't
  in a LAG must have physical port id == logical port id

The implication is that an FDB entry towards a LAG might need to be
deleted and reinstalled when the LAG ID changes.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This change introduces support for installing static FDB entries towards
a bridge port that is a LAG of multiple DSA switch ports, as well as
support for filtering towards the CPU local FDB entries emitted for LAG
interfaces that are bridge ports.

Conceptually, host addresses on LAG ports are identical to what we do
for plain bridge ports. Whereas FDB entries _towards_ a LAG can't simply
be replicated towards all member ports like we do for multicast, or VLAN.
Instead we need new driver API. Hardware usually considers a LAG to be a
"logical port", and sets the entire LAG as the forwarding destination.
The physical egress port selection within the LAG is made by hashing
policy, as usual.

To represent the logical port corresponding to the LAG, we pass by value
a copy of the dsa_lag structure to all switches in the tree that have at
least one port in that LAG.

To illustrate why a refcounted list of FDB entries is needed in struct
dsa_lag, it is enough to say that:
- a LAG may be a bridge port and may therefore receive FDB events even
  while it isn't yet offloaded by any DSA interface
- DSA interfaces may be removed from a LAG while that is a bridge port;
  we don't want FDB entries lingering around, but we don't want to
  remove entries that are still in use, either

For all the cases below to work, the idea is to always keep an FDB entry
on a LAG with a reference count equal to the DSA member ports. So:
- if a port joins a LAG, it requests the bridge to replay the FDB, and
  the FDB entries get created, or their refcount gets bumped by one
- if a port leaves a LAG, the FDB replay deletes or decrements refcount
  by one
- if an FDB is installed towards a LAG with ports already present, that
  entry is created (if it doesn't exist) and its refcount is bumped by
  the amount of ports already present in the LAG

echo "Adding FDB entry to bond with existing ports"
ip link del bond0
ip link add bond0 type bond mode 802.3ad
ip link set swp1 down && ip link set swp1 master bond0 && ip link set swp1 up
ip link set swp2 down && ip link set swp2 master bond0 && ip link set swp2 up
ip link del br0
ip link add br0 type bridge
ip link set bond0 master br0
bridge fdb add dev bond0 00:01:02:03:04:05 master static

ip link del br0
ip link del bond0

echo "Adding FDB entry to empty bond"
ip link del bond0
ip link add bond0 type bond mode 802.3ad
ip link del br0
ip link add br0 type bridge
ip link set bond0 master br0
bridge fdb add dev bond0 00:01:02:03:04:05 master static
ip link set swp1 down && ip link set swp1 master bond0 && ip link set swp1 up
ip link set swp2 down && ip link set swp2 master bond0 && ip link set swp2 up

ip link del br0
ip link del bond0

echo "Adding FDB entry to empty bond, then removing ports one by one"
ip link del bond0
ip link add bond0 type bond mode 802.3ad
ip link del br0
ip link add br0 type bridge
ip link set bond0 master br0
bridge fdb add dev bond0 00:01:02:03:04:05 master static
ip link set swp1 down && ip link set swp1 master bond0 && ip link set swp1 up
ip link set swp2 down && ip link set swp2 master bond0 && ip link set swp2 up

ip link set swp1 nomaster
ip link set swp2 nomaster
ip link del br0
ip link del bond0
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>