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Vladimir Oltean 5aedcc8aa8 net: mscc: ocelot: fix vlan_filtering when enslaving to bridge before link is up 
[ Upstream commit 1c44ce560b ]

Background information: the driver operates the hardware in a mode where
a single VLAN can be transmitted as untagged on a particular egress
port. That is the "native VLAN on trunk port" use case. Its value is
held in port->vid.

Consider the following command sequence (no network manager, all
interfaces are down, debugging prints added by me):

$ ip link add dev br0 type bridge vlan_filtering 1
$ ip link set dev swp0 master br0

Kernel code path during last command:

br_add_slave -> ocelot_netdevice_port_event (NETDEV_CHANGEUPPER):
[   21.401901] ocelot_vlan_port_apply: port 0 vlan aware 0 pvid 0 vid 0

br_add_slave -> nbp_vlan_init -> switchdev_port_attr_set -> ocelot_port_attr_set (SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING):
[   21.413335] ocelot_vlan_port_apply: port 0 vlan aware 1 pvid 0 vid 0

br_add_slave -> nbp_vlan_init -> nbp_vlan_add -> br_switchdev_port_vlan_add -> switchdev_port_obj_add -> ocelot_port_obj_add -> ocelot_vlan_vid_add
[   21.667421] ocelot_vlan_port_apply: port 0 vlan aware 1 pvid 1 vid 1

So far so good. The bridge has replaced the driver's default pvid used
in standalone mode (0) with its own default_pvid (1). The port's vid
(native VLAN) has also changed from 0 to 1.

$ ip link set dev swp0 up

[   31.722956] 8021q: adding VLAN 0 to HW filter on device swp0
do_setlink -> dev_change_flags -> vlan_vid_add -> ocelot_vlan_rx_add_vid -> ocelot_vlan_vid_add:
[   31.728700] ocelot_vlan_port_apply: port 0 vlan aware 1 pvid 1 vid 0

The 8021q module uses the .ndo_vlan_rx_add_vid API on .ndo_open to make
ports be able to transmit and receive 802.1p-tagged traffic by default.
This API is supposed to offload a VLAN sub-interface, which for a switch
port means to add a VLAN that is not a pvid, and tagged on egress.

But the driver implementation of .ndo_vlan_rx_add_vid is wrong: it adds
back vid 0 as "egress untagged". Now back to the initial paragraph:
there is a single untagged VID that the driver keeps track of, and that
has just changed from 1 (the pvid) to 0. So this breaks the bridge
core's expectation, because it has changed vid 1 from untagged to
tagged, when what the user sees is.

$ bridge vlan
port    vlan ids
swp0     1 PVID Egress Untagged

br0      1 PVID Egress Untagged

But curiously, instead of manifesting itself as "untagged and
pvid-tagged traffic gets sent as tagged on egress", the bug:

- is hidden when vlan_filtering=0
- manifests as dropped traffic when vlan_filtering=1, due to this setting:

	if (port->vlan_aware && !port->vid)
		/* If port is vlan-aware and tagged, drop untagged and priority
		 * tagged frames.
		 */
		val |= ANA_PORT_DROP_CFG_DROP_UNTAGGED_ENA |
		       ANA_PORT_DROP_CFG_DROP_PRIO_S_TAGGED_ENA |
		       ANA_PORT_DROP_CFG_DROP_PRIO_C_TAGGED_ENA;

which would have made sense if it weren't for this bug. The setting's
intention was "this is a trunk port with no native VLAN, so don't accept
untagged traffic". So the driver was never expecting to set VLAN 0 as
the value of the native VLAN, 0 was just encoding for "invalid".

So the fix is to not send 802.1p traffic as untagged, because that would
change the port's native vlan to 0, unbeknownst to the bridge, and
trigger unexpected code paths in the driver.

Cc: Antoine Tenart <antoine.tenart@bootlin.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Fixes: 7142529f16 ("net: mscc: ocelot: add VLAN filtering")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-12 19:21:12 +01:00
arch perf/x86/uncore: Fix event group support 2019-11-12 19:21:07 +01:00
block blk-rq-qos: fix first node deletion of rq_qos_del() 2019-10-29 09:20:09 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: skcipher - Unmap pages after an external error 2019-10-11 18:20:52 +02:00
Documentation sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices 2019-11-12 19:20:50 +01:00
drivers net: mscc: ocelot: fix vlan_filtering when enslaving to bridge before link is up 2019-11-12 19:21:12 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs configfs: fix a deadlock in configfs_symlink() 2019-11-12 19:20:47 +01:00
include ipvs: move old_secure_tcp into struct netns_ipvs 2019-11-12 19:21:01 +01:00
init initramfs: don't free a non-existent initrd 2019-10-01 08:26:09 +02:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-08-06 19:06:52 +02:00
kernel sched/fair: Fix -Wunused-but-set-variable warnings 2019-11-12 19:20:51 +01:00
lib dump_stack: avoid the livelock of the dump_lock 2019-11-12 19:20:37 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm, vmstat: hide /proc/pagetypeinfo from normal users 2019-11-12 19:20:36 +01:00
net ipvs: move old_secure_tcp into struct netns_ipvs 2019-11-12 19:21:01 +01:00
samples samples: bpf: fix: seg fault with NULL pointer arg 2019-11-06 13:05:30 +01:00
scripts scripts/setlocalversion: Improve -dirty check with git-status --no-optional-locks 2019-11-06 13:05:27 +01:00
security ima: fix freeing ongoing ahash_request 2019-10-11 18:21:11 +02:00
sound ALSA: usb-audio: Fix copy&paste error in the validator 2019-11-12 19:20:50 +01:00
tools usbip: tools: Fix read_usb_vudc_device() error path handling 2019-11-12 19:21:09 +01:00
usr kbuild: clean compressed initramfs image 2019-10-07 18:57:16 +02:00
virt KVM: coalesced_mmio: add bounds checking 2019-09-21 07:16:44 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:44:47 -07:00
Makefile Linux 4.19.83 2019-11-10 11:27:57 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.