linux-toradex.git/include/linux/dsa, branch v6.12-rc4

net: mscc: ocelot: use ocelot_xmit_get_vlan_info() also for FDMA and register injection

2024-08-16T08:59:32+00:00

Problem description
-------------------

On an NXP LS1028A (felix DSA driver) with the following configuration:

- ocelot-8021q tagging protocol
- VLAN-aware bridge (with STP) spanning at least swp0 and swp1
- 8021q VLAN upper interfaces on swp0 and swp1: swp0.700, swp1.700
- ptp4l on swp0.700 and swp1.700

we see that the ptp4l instances do not see each other's traffic,
and they all go to the grand master state due to the
ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES condition.

Jumping to the conclusion for the impatient
-------------------------------------------

There is a zero-day bug in the ocelot switchdev driver in the way it
handles VLAN-tagged packet injection. The correct logic already exists in
the source code, in function ocelot_xmit_get_vlan_info() added by commit
5ca721c54d86 ("net: dsa: tag_ocelot: set the classified VLAN during xmit").
But it is used only for normal NPI-based injection with the DSA "ocelot"
tagging protocol. The other injection code paths (register-based and
FDMA-based) roll their own wrong logic. This affects and was noticed on
the DSA "ocelot-8021q" protocol because it uses register-based injection.

By moving ocelot_xmit_get_vlan_info() to a place that's common for both
the DSA tagger and the ocelot switch library, it can also be called from
ocelot_port_inject_frame() in ocelot.c.

We need to touch the lines with ocelot_ifh_port_set()'s prototype
anyway, so let's rename it to something clearer regarding what it does,
and add a kernel-doc. ocelot_ifh_set_basic() should do.

Investigation notes
-------------------

Debugging reveals that PTP event (aka those carrying timestamps, like
Sync) frames injected into swp0.700 (but also swp1.700) hit the wire
with two VLAN tags:

00000000: 01 1b 19 00 00 00 00 01 02 03 04 05 81 00 02 bc
                                              ~~~~~~~~~~~
00000010: 81 00 02 bc 88 f7 00 12 00 2c 00 00 02 00 00 00
          ~~~~~~~~~~~
00000020: 00 00 00 00 00 00 00 00 00 00 00 01 02 ff fe 03
00000030: 04 05 00 01 00 04 00 00 00 00 00 00 00 00 00 00
00000040: 00 00

The second (unexpected) VLAN tag makes felix_check_xtr_pkt() ->
ptp_classify_raw() fail to see these as PTP packets at the link
partner's receiving end, and return PTP_CLASS_NONE (because the BPF
classifier is not written to expect 2 VLAN tags).

The reason why packets have 2 VLAN tags is because the transmission
code treats VLAN incorrectly.

Neither ocelot switchdev, nor felix DSA, declare the NETIF_F_HW_VLAN_CTAG_TX
feature. Therefore, at xmit time, all VLANs should be in the skb head,
and none should be in the hwaccel area. This is done by:

static struct sk_buff *validate_xmit_vlan(struct sk_buff *skb,
					  netdev_features_t features)
{
	if (skb_vlan_tag_present(skb) &&
	    !vlan_hw_offload_capable(features, skb->vlan_proto))
		skb = __vlan_hwaccel_push_inside(skb);
	return skb;
}

But ocelot_port_inject_frame() handles things incorrectly:

	ocelot_ifh_port_set(ifh, port, rew_op, skb_vlan_tag_get(skb));

void ocelot_ifh_port_set(struct sk_buff *skb, void *ifh, int port, u32 rew_op)
{
	(...)
	if (vlan_tag)
		ocelot_ifh_set_vlan_tci(ifh, vlan_tag);
	(...)
}

The way __vlan_hwaccel_push_inside() pushes the tag inside the skb head
is by calling:

static inline void __vlan_hwaccel_clear_tag(struct sk_buff *skb)
{
	skb->vlan_present = 0;
}

which does _not_ zero out skb->vlan_tci as seen by skb_vlan_tag_get().
This means that ocelot, when it calls skb_vlan_tag_get(), sees
(and uses) a residual skb->vlan_tci, while the same VLAN tag is
_already_ in the skb head.

The trivial fix for double VLAN headers is to replace the content of
ocelot_ifh_port_set() with:

	if (skb_vlan_tag_present(skb))
		ocelot_ifh_set_vlan_tci(ifh, skb_vlan_tag_get(skb));

but this would not be correct either, because, as mentioned,
vlan_hw_offload_capable() is false for us, so we'd be inserting dead
code and we'd always transmit packets with VID=0 in the injection frame
header.

I can't actually test the ocelot switchdev driver and rely exclusively
on code inspection, but I don't think traffic from 8021q uppers has ever
been injected properly, and not double-tagged. Thus I'm blaming the
introduction of VLAN fields in the injection header - early driver code.

As hinted at in the early conclusion, what we _want_ to happen for
VLAN transmission was already described once in commit 5ca721c54d86
("net: dsa: tag_ocelot: set the classified VLAN during xmit").

ocelot_xmit_get_vlan_info() intends to ensure that if the port through
which we're transmitting is under a VLAN-aware bridge, the outer VLAN
tag from the skb head is stripped from there and inserted into the
injection frame header (so that the packet is processed in hardware
through that actual VLAN). And in all other cases, the packet is sent
with VID=0 in the injection frame header, since the port is VLAN-unaware
and has logic to strip this VID on egress (making it invisible to the
wire).

Fixes: 08d02364b12f ("net: mscc: fix the injection header")
Signed-off-by: Vladimir Oltean 
Signed-off-by: David S. Miller

dsa: lan9303: consistent naming for PHY address parameter

2024-07-15T15:49:59+00:00

Name it 'addr' instead of 'port' or 'phy'.

Signed-off-by: Christian Eggers 
Link: https://patch.msgid.link/20240715123050.21202-1-ceggers@arri.de
Signed-off-by: Jakub Kicinski

net: dsa: prepare 'dsa_tag_8021q_bridge_join' for standalone use

2024-07-15T13:55:16+00:00

The 'dsa_tag_8021q_bridge_join' could be used as a generic implementation
of the 'ds->ops->port_bridge_join()' function. However, it is necessary
to synchronize their arguments.

This patch also moves the 'tx_fwd_offload' flag configuration line into
'dsa_tag_8021q_bridge_join' body. Currently, every (sja1105) driver sets
it, and the future vsc73xx implementation will also need it for
simplification.

Suggested-by: Vladimir Oltean 
Signed-off-by: Pawel Dembicki 
Reviewed-by: Vladimir Oltean 
Link: https://patch.msgid.link/20240713211620.1125910-11-paweldembicki@gmail.com
Signed-off-by: Jakub Kicinski

net: dsa: Define max num of bridges in tag8021q implementation

2024-07-15T13:55:16+00:00

Max number of bridges in tag8021q implementation is strictly limited
by VBID size: 3 bits. But zero is reserved and only 7 values can be used.

This patch adds define which describe maximum possible value.

Suggested-by: Vladimir Oltean 
Signed-off-by: Pawel Dembicki 
Reviewed-by: Florian Fainelli 
Reviewed-by: Linus Walleij 
Reviewed-by: Vladimir Oltean 
Link: https://patch.msgid.link/20240713211620.1125910-10-paweldembicki@gmail.com
Signed-off-by: Jakub Kicinski

net: dsa: Use conduit and user terms

2023-10-24T20:08:14+00:00

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 
Acked-by: Stephen Hemminger 
Reviewed-by: Vladimir Oltean 
Signed-off-by: Florian Fainelli 
Link: https://lore.kernel.org/r/20231023181729.1191071-2-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski

net: dsa: sja1105: always enable the send_meta options

2023-07-04T18:42:27+00:00

incl_srcpt has the limitation, mentioned in commit b4638af8885a ("net:
dsa: sja1105: always enable the INCL_SRCPT option"), that frames with a
MAC DA of 01:80:c2:xx:yy:zz will be received as 01:80:c2:00:00:zz unless
PTP RX timestamping is enabled.

The incl_srcpt option was initially unconditionally enabled, then that
changed with commit 42824463d38d ("net: dsa: sja1105: Limit use of
incl_srcpt to bridge+vlan mode"), then again with b4638af8885a ("net:
dsa: sja1105: always enable the INCL_SRCPT option"). Bottom line is that
it now needs to be always enabled, otherwise the driver does not have a
reliable source of information regarding source_port and switch_id for
link-local traffic (tag_8021q VLANs may be imprecise since now they
identify an entire bridging domain when ports are not standalone).

If we accept that PTP RX timestamping (and therefore, meta frame
generation) is always enabled in hardware, then that limitation could be
avoided and packets with any MAC DA can be properly received, because
meta frames do contain the original bytes from the MAC DA of their
associated link-local packet.

This change enables meta frame generation unconditionally, which also
has the nice side effects of simplifying the switch control path
(a switch reset is no longer required on hwtstamping settings change)
and the tagger data path (it no longer needs to be informed whether to
expect meta frames or not - it always does).

Fixes: 227d07a07ef1 ("net: dsa: sja1105: Add support for traffic through standalone ports")
Signed-off-by: Vladimir Oltean 
Reviewed-by: Simon Horman 
Reviewed-by: Florian Fainelli 
Signed-off-by: David S. Miller

net: dsa: microchip: ptp: move pdelay_rsp correction field to tail tag

2023-01-13T08:40:41+00:00

For PDelay_Resp messages we will likely have a negative value in the
correction field. The switch hardware cannot correctly update such
values (produces an off by one error in the UDP checksum), so it must be
moved to the time stamp field in the tail tag. Format of the correction
field is 48 bit ns + 16 bit fractional ns.  After updating the
correction field, clone is no longer required hence it is freed.

Signed-off-by: Christian Eggers 
Co-developed-by: Arun Ramadoss 
Signed-off-by: Arun Ramadoss 
Signed-off-by: David S. Miller

net: dsa: microchip: ptp: add packet transmission timestamping

2023-01-13T08:40:41+00:00

This patch adds the routines for transmission of ptp packets. When the
ptp pdelay_req packet to be transmitted, it uses the deferred xmit
worker to schedule the packets.
During irq_setup, interrupt for Sync, Pdelay_req and Pdelay_rsp are
enabled. So interrupt is triggered for all three packets. But for
p2p1step, we require only time stamp of Pdelay_req packet. Hence to
avoid posting of the completion from ISR routine for Sync and
Pdelay_resp packets, ts_en flag is introduced. This controls which
packets need to processed for timestamp.
After the packet is transmitted, ISR is triggered. The time at which
packet transmitted is recorded to separate register.
This value is reconstructed to absolute time and posted to the user
application through socket error queue.

Signed-off-by: Christian Eggers 
Co-developed-by: Arun Ramadoss 
Signed-off-by: Arun Ramadoss 
Reviewed-by: Vladimir Oltean 
Signed-off-by: David S. Miller

net: dsa: microchip: ptp: add packet reception timestamping

2023-01-13T08:40:41+00:00

Rx Timestamping is done through 4 additional bytes in tail tag.
Whenever the ptp packet is received, the 4 byte hardware time stamped
value is added before 1 byte tail tag. Also, bit 7 in tail tag indicates
it as PTP frame. This 4 byte value is extracted from the tail tag and
reconstructed to absolute time and assigned to skb hwtstamp.
If the packet received in PDelay_Resp, then partial ingress timestamp
is subtracted from the correction field. Since user space tools expects
to be done in hardware.

Signed-off-by: Christian Eggers 
Co-developed-by: Arun Ramadoss 
Signed-off-by: Arun Ramadoss 
Reviewed-by: Vladimir Oltean 
Signed-off-by: David S. Miller

net: dsa: microchip: ptp: add 4 bytes in tail tag when ptp enabled

2023-01-13T08:40:40+00:00

When the PTP is enabled in hardware bit 6 of PTP_MSG_CONF1 register, the
transmit frame needs additional 4 bytes before the tail tag. It is
needed for all the transmission packets irrespective of PTP packets or
not.
The 4-byte timestamp field is 0 for frames other than Pdelay_Resp. For
the one-step Pdelay_Resp, the switch needs the receive timestamp of the
Pdelay_Req message so that it can put the turnaround time in the
correction field.
Since PTP has to be enabled for both Transmission and reception
timestamping, driver needs to track of the tx and rx setting of the all
the user ports in the switch.
Two flags hw_tx_en and hw_rx_en are added in ksz_port to track the
timestampping setting of each port. When any one of ports has tx or rx
timestampping enabled, bit 6 of PTP_MSG_CONF1 is set and it is indicated
to tag_ksz.c through tagger bytes. This flag adds 4 additional bytes to
the tail tag.  When tx and rx timestamping of all the ports are disabled,
then 4 bytes are not added.

Tested using hwstamp -i 

Signed-off-by: Arun Ramadoss 
Reviewed-by: Vladimir Oltean  # mostly api
Signed-off-by: David S. Miller