net: fill in MODULE_DESCRIPTION()s for DSA tags

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to all the DSA tag modules.

The descriptions are copy/pasted Kconfig names, with s/^Tag/DSA tag/.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Acked-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20240104143759.1318137-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: Use conduit and user terms

Use more inclusive terms throughout the DSA subsystem by moving away
from "master" which is replaced by "conduit" and "slave" which is
replaced by "user". No functional changes.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20231023181729.1191071-2-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: move tagging protocol code to tag.{c,h}

It would be nice if tagging protocol drivers could include just the
header they need, since they are (mostly) data path and isolated from
most of the other DSA core code does.

Create a tag.c and a tag.h file which are meant to support tagging
protocol drivers.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: tag_mtk: assign per-port queues

Keeps traffic sent to the switch within link speed limits

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20221116080734.44013-6-nbd@nbd.name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: provide a second modalias to tag proto drivers based on their name

Currently, tagging protocol drivers have a modalias of
"dsa_tag:id-<number>", where the number is one of DSA_TAG_PROTO_*_VALUE.

This modalias makes it possible for the request_module() call in
dsa_tag_driver_get() to work, given the input it has - an integer
returned by ds->ops->get_tag_protocol().

It is also possible to change tagging protocols at (pseudo-)runtime, via
sysfs or via device tree, and this works via the name string of the
tagging protocol rather than via its id (DSA_TAG_PROTO_*_VALUE).

In the latter case, there is no request_module() call, because there is
no association that the DSA core has between the string name and the ID,
to construct the modalias. The module is simply assumed to have been
inserted. This is actually slightly problematic when the tagging
protocol change should take place at probe time, since it's expected
that the dependency module should get autoloaded.

For this purpose, let's introduce a second modalias, so that the DSA
core can call request_module() by name. There is no reason to make the
modalias by name optional, so just modify the MODULE_ALIAS_DSA_TAG_DRIVER()
macro to take both the ID and the name as arguments, and generate two
modaliases behind the scenes.

Suggested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc> # on kontron-sl28 w/ ocelot_8021q
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: create a helper for locating EtherType DSA headers on TX

Create a similar helper for locating the offset to the DSA header
relative to skb->data, and make the existing EtherType header taggers to
use it.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: create a helper for locating EtherType DSA headers on RX

It seems that protocol tagging driver writers are always surprised about
the formula they use to reach their EtherType header on RX, which
becomes apparent from the fact that there are comments in multiple
drivers that mention the same information.

Create a helper that returns a void pointer to skb->data - 2, as well as
centralize the explanation why that is the case.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: create a helper which allocates space for EtherType DSA headers

Hide away the memmove used by DSA EtherType header taggers to shift the
MAC SA and DA to the left to make room for the header, after they've
called skb_push(). The call to skb_push() is still left explicit in
drivers, to be symmetric with dsa_strip_etype_header, and because not
all callers can be refactored to do it (for example, brcm_tag_xmit_ll
has common code for a pre-Ethernet DSA tag and an EtherType DSA tag).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: create a helper that strips EtherType DSA headers on RX

All header taggers open-code a memmove that is fairly not all that
obvious, and we can hide the details behind a helper function, since the
only thing specific to the driver is the length of the header tag.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: remove the struct packet_type argument from dsa_device_ops::rcv()

No tagging driver uses this.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: don't set skb->offload_fwd_mark when not offloading the bridge

DSA has gained the recent ability to deal gracefully with upper
interfaces it cannot offload, such as the bridge, bonding or team
drivers. When such uppers exist, the ports are still in standalone mode
as far as the hardware is concerned.

But when we deliver packets to the software bridge in order for that to
do the forwarding, there is an unpleasant surprise in that the bridge
will refuse to forward them. This is because we unconditionally set
skb->offload_fwd_mark = true, meaning that the bridge thinks the frames
were already forwarded in hardware by us.

Since dp->bridge_dev is populated only when there is hardware offload
for it, but not in the software fallback case, let's introduce a new
helper that can be called from the tagger data path which sets the
skb->offload_fwd_mark accordingly to zero when there is no hardware
offload for bridging. This lets the bridge forward packets back to other
interfaces of our switch, if needed.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: generalize overhead for taggers that use both headers and trailers

Some really really weird switches just couldn't decide whether to use a
normal or a tail tagger, so they just did both.

This creates problems for DSA, because we only have the concept of an
'overhead' which can be applied to the headroom or to the tailroom of
the skb (like for example during the central TX reallocation procedure),
depending on the value of bool tail_tag, but not to both.

We need to generalize DSA to cater for these odd switches by
transforming the 'overhead / tail_tag' pair into 'needed_headroom /
needed_tailroom'.

The DSA master's MTU is increased to account for both.

The flow dissector code is modified such that it only calls the DSA
adjustment callback if the tagger has a non-zero header length.

Taggers are trivially modified to declare either needed_headroom or
needed_tailroom, based on the tail_tag value that they currently
declare.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: mt7530: support MDB and bridge flag operations

Support port MDB and bridge flag operations.

As the hardware can manage multicast forwarding itself, offload_fwd_mark
can be unconditionally set to true.

Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_mtk: fix 802.1ad VLAN egress

A different TPID bit is used for 802.1ad VLAN frames.

Reported-by: Ilario Gelmetti <iochesonome@gmail.com>
Fixes: f0af34317f4b ("net: dsa: mediatek: combine MediaTek tag with VLAN tag")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_mtk: let DSA core deal with TX reallocation

Now that we have a central TX reallocation procedure that accounts for
the tagger's needed headroom in a generic way, we can remove the
skb_cow_head call.

Cc: DENG Qingfang <dqfext@gmail.com>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: John Crispin <john@phrozen.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: tag_mtk: use the generic flow dissector procedure

Remove the .flow_dissect procedure, so the flow dissector will call the
generic variant which works for this tagging protocol.

Cc: DENG Qingfang <dqfext@gmail.com>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: John Crispin <john@phrozen.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: make the .flow_dissect tagger callback return void

There is no tagger that returns anything other than zero, so just change
the return type appropriately.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_mtk: Fix warnings for __be16

net/dsa/tag_mtk.c:84:13: warning: incorrect type in assignment (different base types)
net/dsa/tag_mtk.c:84:13: expected restricted __be16 [usertype] hdr
net/dsa/tag_mtk.c:84:13: got int
net/dsa/tag_mtk.c:94:17: warning: restricted __be16 degrades to integer

The result of a ntohs() is not __be16, but u16.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: mt7530: fix roaming from DSA user ports

When a client moves from a DSA user port to a software port in a bridge,
it cannot reach any other clients that connected to the DSA user ports.
That is because SA learning on the CPU port is disabled, so the switch
ignores the client's frames from the CPU port and still thinks it is at
the user port.

Fix it by enabling SA learning on the CPU port.

To prevent the switch from learning from flooding frames from the CPU
port, set skb->offload_fwd_mark to 1 for unicast and broadcast frames,
and let the switch flood them instead of trapping to the CPU port.
Multicast frames still need to be trapped to the CPU port for snooping,
so set the SA_DIS bit of the MTK tag to 1 when transmitting those frames
to disable SA learning.

Fixes: b8f126a8d543 ("net-next: dsa: add dsa support for Mediatek MT7530 switch")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Cleanup unneeded table and make tag structures static

Now that tag drivers dynamically register, we don't need the static
table. Remove it. This also means the tag driver structures can be
made static.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add boilerplate helper to register DSA tag driver modules

A DSA tag driver module will need to register the tag protocols it
implements with the DSA core. Add macros containing this boiler plate.

The registration/unregistration code is currently just a stub. A Later
patch will add the real implementation.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

v2
Fix indent of #endif
Rewrite to move list pointer into a new structure
v3
Move kdoc next to macro
Fix THIS_MODULE indentation

Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add TAG protocol to tag ops

In order that we can match the tagging protocol a switch driver
request to the tagger, we need to know what protocol the tagger
supports. Add this information to the ops structure.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

v2
More tag protocol to end of structure to keep hot members at the beginning.

Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add MODULE_LICENSE to tag drivers

All the tag drivers are some variant of GPL. Add a MODULE_LICENSE()
indicating this, so the drivers can later be compiled as modules.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add MODULE_ALIAS to taggers in preparation to become modules

When the tag drivers become modules, we will need to dynamically load
them based on what the switch drivers need. Add aliases to map between
the TAG protocol and the driver.

In order to do this, we need the tag protocol number as something
which the C pre-processor can stringinfy. Only the compiler knows the
value of an enum, CPP cannot use them. So add #defines.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Move tagger name into its ops structure

Rather than keep a list to map a tagger ops to a name, place the name
into the ops structure. This removes the hard coded list, a step
towards making the taggers more dynamic.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

v2:
Move name to end of structure, keeping the hot entries at the beginning.

Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add SPDX header to tag drivers.

Add an SPDX header, and remove the license boilerplate text.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Add overhead to tag protocol ops.

Each DSA tag protocol needs to add additional headers to the Ethernet
frame in order to direct it towards a specific switch egress port. It
must also remove the head from a frame received from a
switch. Indicate the maximum size of these headers in the tag protocol
ops structure, so the core can take these overheads into account.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: mediatek: combine MediaTek tag with VLAN tag

In order to let MT7530 switch can recognize well those egress packets
having both special tag and VLAN tag, the information about the special
tag should be carried on the existing VLAN tag. On the other hand, it's
unnecessary for extra handling for ingress packets when VLAN tag is
present since it is able to put the VLAN tag after the special tag and
then follow the existing way to parse.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: rename dsa_master_get_slave

The dsa_master_get_slave is slightly confusing since the idiomatic "get"
term often suggests reference counting, in symmetry to "put".

Rename it to dsa_master_find_slave to make the look up operation clear.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: add slave to port helper

Many portions of DSA core code require to get the dsa_port structure
corresponding to a slave net_device. For this purpose, introduce a
dsa_slave_to_port() helper.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: add master helper to look up slaves

The DSA tagging code does not need to know about the DSA architecture,
it only needs to return the slave device corresponding to the source
port index (and eventually the source device index for cascade-capable
switches) parsed from the frame received on the master device.

For this purpose, provide an inline dsa_master_get_slave helper which
validates the device and port indexes and look up the slave device.

This makes the tagging rcv functions more concise and robust, and also
makes dsa_get_cpu_port obsolete.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: remove unused net_device arg from handlers

compile tested only, but saw no warnings/errors with
allmodconfig build.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net-next: tag_mtk: add flow_dissect callback to the ops struct

The MT7530 inserts the 4 magic header in between the 802.3 address and
protocol field. The patch implements the callback that can be called by
the flow dissector to figure out the real protocol and offset of the
network header. With this patch applied we can properly parse the packet
and thus make hashing function properly.

Signed-off-by: Muciri Gatimu <muciri@openmesh.com>
Signed-off-by: Shashidhar Lakkavalli <shashidhar.lakkavalli@openmesh.com>
Signed-off-by: John Crispin <john@phrozen.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: factor skb freeing on xmit

As of a86d8becc3f0 ("net: dsa: Factor bottom tag receive functions"),
the rcv caller frees the original SKB in case or error.

Be symmetric with that and make the xmit caller do the same.

At the same time, fix the checkpatch NULL comparison check:

CHECK: Comparison to NULL could be written "!nskb"
#208: FILE: net/dsa/tag_trailer.c:35:
+ if (nskb == NULL)

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: remove out_drop label in taggers rcv

Many rcv functions from net/dsa/tag_*.c have a useless out_drop goto
label which simply returns NULL. Kill it in favor of the obvious.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: include dsa.h only once

The public include/net/dsa.h file is meant for DSA drivers, while all
DSA core files share a common private header net/dsa/dsa_priv.h file.

Ensure that dsa_priv.h is the only DSA core file to include net/dsa.h,
and add a new line to separate absolute and relative headers at the same
time.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Factor bottom tag receive functions

All DSA tag receive functions do strictly the same thing after they have located
the originating source port from their tag specific protocol:

- push ETH_HLEN bytes
- set pkt_type to PACKET_HOST
- call eth_type_trans()
- bump up counters
- call netif_receive_skb()

Factor all of that into dsa_switch_rcv(). This also makes us return a pointer to
a sk_buff, which makes us symetric with the xmit function.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Move skb_unshare() to dsa_switch_rcv()

All DSA tag receive functions need to unshare the skb before mangling it, move
this to the generic dsa_switch_rcv() function which will allow us to make the
tag receive function return their mangled skb without caring about freeing a
NULL skb.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Do not check for NULL dst in tag parsers

dsa_switch_rcv() already tests for dst == NULL, so there is no need to duplicate
the same check within the tag receive functions.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net-next: dsa: add Mediatek tag RX/TX handler

Add the support for the 4-bytes tag for DSA port distinguishing inserted
allowing receiving and transmitting the packet via the particular port.
The tag is being added after the source MAC address in the ethernet
header.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Landen Chao <Landen.Chao@mediatek.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>