Implement support for processing the IOAM Pre-allocated Trace with IPv6,
see [1] and [2]. Introduce a new IPv6 Hop-by-Hop TLV option, see IANA [3].

A new per-interface sysctl is introduced. The value is a boolean to accept (=1)
or ignore (=0, by default) IPv6 IOAM options on ingress for an interface:
 - net.ipv6.conf.XXX.ioam6_enabled

Two other sysctls are introduced to define IOAM IDs, represented by an integer.
They are respectively per-namespace and per-interface:
 - net.ipv6.ioam6_id
 - net.ipv6.conf.XXX.ioam6_id

The value of the first one represents the IOAM ID of the node itself (u32; max
and default value = U32_MAX>>8, due to hop limit concatenation) while the other
represents the IOAM ID of an interface (u16; max and default value = U16_MAX).

Each "ioam6_id" sysctl has a "_wide" equivalent:
 - net.ipv6.ioam6_id_wide
 - net.ipv6.conf.XXX.ioam6_id_wide

The value of the first one represents the wide IOAM ID of the node itself (u64;
max and default value = U64_MAX>>8, due to hop limit concatenation) while the
other represents the wide IOAM ID of an interface (u32; max and default value
= U32_MAX).

The use of short and wide equivalents is not exclusive, a deployment could
choose to leverage both. For example, net.ipv6.conf.XXX.ioam6_id (short format)
could be an identifier for a physical interface, whereas
net.ipv6.conf.XXX.ioam6_id_wide (wide format) could be an identifier for a
logical sub-interface. Documentation about new sysctls is provided at the end
of this patchset.

Two relativistic hash tables are used: one for IOAM namespaces, the other for
IOAM schemas. A namespace can only have a single active schema and a schema
can only be attached to a single namespace (1:1 relationship).

  [1] https://tools.ietf.org/html/draft-ietf-ippm-ioam-ipv6-options
  [2] https://tools.ietf.org/html/draft-ietf-ippm-ioam-data
  [3] https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch provides the IPv6 IOAM option header [1] as well as the IOAM
Trace header [2]. An IOAM option must be 4n-aligned. Here is an overview of
a Hop-by-Hop with an IOAM Trace option:

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Next header  |  Hdr Ext Len  |    Padding    |    Padding    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Option Type  |  Opt Data Len |    Reserved   |   IOAM Type   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|         Namespace-ID          | NodeLen | Flags | RemainingLen|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                IOAM-Trace-Type                |    Reserved   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
|                                                               |  |
|                         node data [n]                         |  |
|                                                               |  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  D
|                                                               |  a
|                         node data [n-1]                       |  t
|                                                               |  a
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                             ...                               ~  S
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  p
|                                                               |  a
|                         node data [1]                         |  c
|                                                               |  e
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  |
|                                                               |  |
|                         node data [0]                         |  |
|                                                               |  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+

The IOAM option header starts at "Option Type" and ends after "IOAM
Type". The IOAM Trace header starts at "Namespace-ID" and ends after
"IOAM-Trace-Type/Reserved".

IOAM Type: either Pre-allocated Trace (=0), Incremental Trace (=1),
Proof-of-Transit (=2) or Edge-to-Edge (=3). Note that both the
Pre-allocated Trace and the Incremental Trace look the same. The two
others are not implemented.

Namespace-ID: IOAM namespace identifier, not to be confused with network
namespaces. It adds further context to IOAM options and associated data,
and allows devices which are IOAM capable to determine whether IOAM
options must be processed or ignored. It can also be used by an operator
to distinguish different operational domains or to identify different
sets of devices.

NodeLen: Length of data added by each node. It depends on the Trace
Type.

Flags: Only the Overflow (O) flag for now. The O flag is set by a
transit node when there are not enough octets left to record its data.

RemainingLen: Remaining free space to record data.

IOAM-Trace-Type: Bit field where each bit corresponds to a specific kind
of IOAM data. See [2] for a detailed list.

  [1] https://tools.ietf.org/html/draft-ietf-ippm-ioam-ipv6-options
  [2] https://tools.ietf.org/html/draft-ietf-ippm-ioam-dataSigned-off-by: Justin Iurman <justin.iurman@uliege.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

The difference between __switchdev_handle_fdb_del_to_device and
switchdev_handle_del_to_device is that the former takes an extra
orig_dev argument, while the latter starts with dev == orig_dev.

We should recurse into the variant that does not lose the orig_dev along
the way. This is relevant when deleting FDB entries pointing towards a
bridge (dev changes to the lower interfaces, but orig_dev shouldn't).

The addition helper already recurses properly, just the deletion one
doesn't.

Fixes: 8ca07176 ("net: switchdev: introduce a fanout helper for SWITCHDEV_FDB_{ADD,DEL}_TO_DEVICE")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

With the semicolon at the end, the compiler sees the shim function as a
declaration and not as a definition, and warns:

'switchdev_handle_fdb_del_to_device' declared 'static' but never defined
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 8ca07176 ("net: switchdev: introduce a fanout helper for SWITCHDEV_FDB_{ADD,DEL}_TO_DEVICE")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

The blamed commit was probably not tested on net-next, since it did not
refactor the extra phy id check introduced in commit b856150c ("net:
phy: at803x: mask 1000 Base-X link mode").

Fixes: 8887ca54 ("net: phy: at803x: simplify custom phy id matching")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

We only need to fiddle about with the supported mask after we have
validated the user's requested parameters. Simplify and streamline the
code by moving the linkmode copy and update of the autoneg bit after
validating the user's request.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Tony Nguyen says:

====================
1GbE Intel Wired LAN Driver Updates 2021-07-20

This series contains updates to e1000e and igc drivers.

Sasha adds initial S0ix support for devices with CSME and adds polling
for exiting of DPG. He sets the PHY to low power idle when in S0ix. He
also adds support for new device IDs for and adds a space to debug
messaging to help with readability for e1000e.

For igc, he ensures that q_vector array is not accessed beyond its
bounds and removes unneeded PHY related checks.

Tree Davies corrects a spelling mistake in e1000e.

Muhammad corrects the value written when there is no TSN offloading
and adjusts timeout value to avoid possible Tx hang for igc.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch changs interrupt order which found by dtbs_check.

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- dtbs_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/net/nxp,dwmac-imx.yaml
arch/arm64/boot/dts/freescale/imx8mp-evk.dt.yaml: ethernet@30bf0000: interrupt-names:0: 'macirq' was expected
arch/arm64/boot/dts/freescale/imx8mp-evk.dt.yaml: ethernet@30bf0000: interrupt-names:1: 'eth_wake_irq' was expected

According to Documentation/devicetree/bindings/net/snps,dwmac.yaml, we
should list interrupt in it's order.
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In order to automate the verification of DT nodes covert imx-dwmac to
nxp,dwmac-imx.yaml, and pass below checking.

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/net/nxp,dwmac-imx.yaml
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- dtbs_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/net/nxp,dwmac-imx.yaml
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add missing DWMAC IP version in snps,dwmac.yaml which found by below
command, as NXP i.MX8 families support SNPS DWMAC 5.10a IP.

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/net/nxp,dwmac-imx.yaml
Documentation/devicetree/bindings/net/nxp,dwmac-imx.example.dt.yaml:
ethernet@30bf0000: compatible: None of ['nxp,imx8mp-dwmac-eqos', 'snps,dwmac-5.10a'] are valid under the given schema
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

As the cycle time is set to maximum of 1s, the TX Hang timeout need to
be increase to avoid possible TX Hang.

There is no dedicated number specific in data sheet for the timeout factor.
Timeout factor was determined during the debugging to solve the "Tx Hang"
issues that happen in some cases mainly during ETF(Earliest TxTime First).

This can be test by using TSN Schedule Tx Tools udp_tai sample application.
Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Acked-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

According to datasheet section 8.12.19, when there's no TSN offloading
Shadow_QbvCycle bit[29:0] must be set to zero for basic scheduling.
Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

i225 devices have only one phy->type: copper. There is no point checking
phy->type during the igc_has_link method from the watchdog that
invoked every 2 seconds.
This patch comes to clean up these pointless checkings.
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

i225 devices have only one PHY vendor. There is no point checking
_I_PHY_ID during the link establishment and auto-negotiation process.
This patch comes to clean up these pointless checkings.
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Ensure that the adapter->q_vector[MAX_Q_VECTORS] array isn't accessed
beyond its size. It was fixed by using a local variable num_q_vectors
as a limit for loop index, and ensure that num_q_vectors is not bigger
than MAX_Q_VECTORS.
Suggested-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

There is a spelling mistake in the comment block.
Signed-off-by: Tree Davies <tdavies@darkphysics.net>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Minor fixes to allow debug prints more readable.
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Add devices IDs for the next LOM generations that will be
available on the next Intel Client platforms
This patch provides the initial support for these devices
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Add devices IDs for the next LOM generations that will be
available on the next Intel Client platform (Lunar Lake)
This patch provides the initial support for these devices
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

After transferring the MAC-PHY interface to the SMBus set the PHY
to S0ix low power idle mode.
Suggested-by: Dima Ruinskiy <dima.ruinskiy@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Per guidance from the CSME architecture team, it may take
up to 1 second for unconfiguring dynamic power gating mode.
Practically it can take more time. Wait up to 2.5 seconds to indicate
dynamic power gating exit from the S0ix configuration. Detect
scenarios that take more than 1 second but less than 2.5 seconds
will emit warning message.
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

On the corporate system, the driver will ask from the CSME
(manageability engine) to perform device settings are required
to allow S0ix residency.
This patch provides initial support.
Reviewed-by: Dima Ruinskiy <dima.ruinskiy@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

The at803x driver contains a function, at803x_match_phy_id(), which
tests whether the PHY ID matches the value passed, comparing phy_id
with phydev->phy_id and testing all bits that in the driver's mask.

This is the same test that is used to match the driver, with phy_id
replaced with the driver specified ID, phydev->drv->phy_id.

Hence, we already know the value of the bits being tested if we look
at phydev->drv->phy_id directly, and we do not require a complicated
test to check them. Test directly against phydev->drv->phy_id instead.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

The character sequence ??! is a trigraph and causes the following
clang warning:

drivers/net/ethernet/marvell/mvneta.c:2604:39: warning: trigraph ignored [-Wtrigraphs]

Clean this by replacing it with single ?.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The character sequence ??) is a trigraph and causes the following
clang warning:

drivers/atm/idt77252.c:3544:35: warning: trigraph ignored [-Wtrigraphs]

Clean this by replacing it with single ?.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This adds the possibility to configure the RGMII RX/TX clock skew via
devicetree.

Simply set phy mode to "rgmii-id", "rgmii-rxid" or "rgmii-txid" and add
the "rx-internal-delay-ps" or "tx-internal-delay-ps" property to the
devicetree.

Furthermore, a warning is now issued if the phy mode is configured to
"rgmii" and an internal delay is set in the phy (e.g. by pin-strapping),
as in the dp83867 driver.
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Augment the phy link debug prints with the pause state.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

The documentation for Armada 8040 says:

  Bit 2 Field InBandAnEn In-band Auto-Negotiation enable. ...
  When <PortType> = 1 (1000BASE-X) this field must be set to 1.

We presently ignore whether userspace requests autonegotiation or not
through the ethtool ksettings interface. However, we have some network
interfaces that wish to do this. To offer a consistent API across
network interfaces, deny the ability to disable autonegotiation on
mvpp2 hardware when in 1000BASE-X and 2500BASE-X.

This means the only way to switch between 2500BASE-X and 1000BASE-X
on SFPs that support this will be:

 # ethtool -s ethX advertise 0x20000006000 # 1000BASE-X Pause AsymPause
 # ethtool -s ethX advertise 0xe000        # 2500BASE-X Pause AsymPause
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Marek Behún <kabel@kernel.org>
Acked-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The documentation for Armada 38x says:

  Bit 2 Field InBandAnEn In-band Auto-Negotiation enable. ...
  When <PortType> = 1 (1000BASE-X) this field must be set to 1.

We presently ignore whether userspace requests autonegotiation or not
through the ethtool ksettings interface. However, we have some network
interfaces that wish to do this. To offer a consistent API across
network interfaces, deny the ability to disable autonegotiation on
mvneta hardware when in 1000BASE-X and 2500BASE-X.

This means the only way to switch between 2500BASE-X and 1000BASE-X
on SFPs that support this will be:

 # ethtool -s ethX advertise 0x20000002000 # 1000BASE-X Pause
 # ethtool -s ethX advertise 0xa000        # 2500BASE-X Pause
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Marek Behún <kabel@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Root in init user namespace can modify /proc/sys/net/ipv4/ip_forward
without CAP_NET_ADMIN, this doesn't follow the principle of
capabilities. For example, let's take a look at netdev_store(),
root can't modify netdev attribute without CAP_NET_ADMIN.
So let's keep the consistency of permission check logic.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

Alex Elder says:

====================
arm64: dts: qcom: DTS updates

This series updates some IPA-related DT nodes.

Newer versions of IPA do not require an interconnect between IPA
and SoC internal memory.  The first patch updates the DT binding
to reflect this.

The second patch adds IPA information to "sc7280.dtsi", using only
two interconnects.  It includes the definition of the reserved
memory area used to hold IPA firmware.

The last patch defines the reserved IPA firmware memory area in
"sc7180.dtsi".
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Define the reserved memory space used for IPA firmware for the
Qualcomm SC7180 SoC.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add IPA-related nodes and definitions to "sc7280.dtsi", including
the reserved memory area used for AP-based IPA firmware loading.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

On some newer SoCs, the interconnect between IPA and SoC internal
memory (imem) is not used.  Reflect this in the binding by moving
the definition of the "imem" interconnect to the end and defining
minItems to be 2 for both the interconnects and interconnect-names
properties.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently three interconnects are defined for the Qualcomm SC7280
SoC, but this was based on a misunderstanding.  There should only be
two interconnects defined:  one between the IPA and system memory;
and another between the AP and IPA config space.  The bandwidths
defined for the memory and config interconnects do not match what I
understand to be proper values, so update these.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The following warning is observed when running 'make dtbs_check':
Documentation/devicetree/bindings/net/fsl,fec.yaml:85:7: [warning] wrong indentation: expected 8 but found 6 (indentation)

Fix the indentation accordingly.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Vladimir Oltean says:

====================
Fan out FDB entries pointing towards the bridge to all switchdev member ports

The "DSA RX filtering" series has added some important support for
interpreting addresses towards the bridge device as host addresses and
installing them as FDB entries towards the CPU port, but it does not
cover all circumstances and needs further work.

To be precise, the mechanism introduced in that series only works as
long as the ports are fairly static and no port joins or leaves the
bridge once the configuration is done. If any port leaves, host FDB
entries that were installed during runtime (for example the user changes
the MAC address of the bridge device) will be prematurely deleted,
resulting in a broken setup.

I see this work as targeted for "net-next" because technically it was
not supposed to work. Also, there are still corner cases and holes to be
plugged. For example, today, FDB entries on foreign interfaces are not
covered by br_fdb_replay(), which means that there are cases where some
host addresses are either lost, or never deleted by DSA. That will be
resolved once more work gets accepted, in particular the "Allow
forwarding for the software bridge data path to be offloaded to capable
devices" series, which moves the br_fdb_replay() call to the bridge core
and therefore would be required to solve the problem in a generic way
for every switchdev driver and not just for DSA.

These patches also pave the way for a cleaner implementation for FDB
entries pointing towards a LAG upper interface in DSA (that code needs
only to be added, nothing changed), however this is not done here.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Using the new fan-out helper for FDB entries installed on the software
bridge, we can install host addresses with the proper refcount on the
CPU port, such that this case:

ip link set swp0 master br0
ip link set swp1 master br0
ip link set swp2 master br0
ip link set swp3 master br0
ip link set br0 address 00:01:02:03:04:05
ip link set swp3 nomaster

works properly and the br0 address remains installed as a host entry
with refcount 3 instead of getting deleted.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently DSA has an issue with FDB entries pointing towards the bridge
in the presence of br_fdb_replay() being called at port join and leave
time.

In particular, each bridge port will ask for a replay for the FDB
entries pointing towards the bridge when it joins, and for another
replay when it leaves.

This means that for example, a bridge with 4 switch ports will notify
DSA 4 times of the bridge MAC address.

But if the MAC address of the bridge changes during the normal runtime
of the system, the bridge notifies switchdev [ once ] of the deletion of
the old MAC address as a local FDB towards the bridge, and of the
insertion [ again once ] of the new MAC address as a local FDB.

This is a problem, because DSA keeps the old MAC address as a host FDB
entry with refcount 4 (4 ports asked for it using br_fdb_replay). So the
old MAC address will not be deleted. Additionally, the new MAC address
will only be installed with refcount 1, and when the first switch port
leaves the bridge (leaving 3 others as still members), it will delete
with it the new MAC address of the bridge from the local FDB entries
kept by DSA (because the br_fdb_replay call on deletion will bring the
entry's refcount from 1 to 0).

So the problem, really, is that the number of br_fdb_replay() calls is
not matched with the refcount that a host FDB is offloaded to DSA during
normal runtime.

An elegant way to solve the problem would be to make the switchdev
notification emitted by br_fdb_change_mac_address() result in a host FDB
kept by DSA which has a refcount exactly equal to the number of ports
under that bridge. Then, no matter how many DSA ports join or leave that
bridge, the host FDB entry will always be deleted when there are exactly
zero remaining DSA switch ports members of the bridge.

To implement the proposed solution, we remember that the switchdev
objects and port attributes have some helpers provided by switchdev,
which can be optionally called by drivers:
switchdev_handle_port_obj_{add,del} and switchdev_handle_port_attr_set.
These helpers:
- fan out a switchdev object/attribute emitted for the bridge towards
  all the lower interfaces that pass the check_cb().
- fan out a switchdev object/attribute emitted for a bridge port that is
  a LAG towards all the lower interfaces that pass the check_cb().

In other words, this is the model we need for the FDB events too:
something that will keep an FDB entry emitted towards a physical port as
it is, but translate an FDB entry emitted towards the bridge into N FDB
entries, one per physical port.

Of course, there are many differences between fanning out a switchdev
object (VLAN) on 3 lower interfaces of a LAG and fanning out an FDB
entry on 3 lower interfaces of a LAG. Intuitively, an FDB entry towards
a LAG should be treated specially, because FDB entries are unicast, we
can't just install the same address towards 3 destinations. It is
imaginable that drivers might want to treat this case specifically, so
create some methods for this case and do not recurse into the LAG lower
ports, just the bridge ports.

DSA also listens for FDB entries on "foreign" interfaces, aka interfaces
bridged with us which are not part of our hardware domain: think an
Ethernet switch bridged with a Wi-Fi AP. For those addresses, DSA
installs host FDB entries. However, there we have the same problem
(those host FDB entries are installed with a refcount of only 1) and an
even bigger one which we did not have with FDB entries towards the
bridge:

br_fdb_replay() is currently not called for FDB entries on foreign
interfaces, just for the physical port and for the bridge itself.

So when DSA sniffs an address learned by the software bridge towards a
foreign interface like an e1000 port, and then that e1000 leaves the
bridge, DSA remains with the dangling host FDB address. That will be
fixed separately by replaying all FDB entries and not just the ones
towards the port and the bridge.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

It is a bit difficult to understand what DSA checks when it tries to
avoid installing dynamically learned addresses on foreign interfaces as
local host addresses, so create a generic switchdev helper that can be
reused and is generally more readable.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>