wifi: mac80211: add support for restricting netdev features per vif

This can be used to selectively disable feature flags for checksum offload,
scatter/gather or GSO by changing vif->netdev_features.
Removing features from vif->netdev_features does not affect the netdev
features themselves, but instead fixes up skbs in the tx path so that the
offloads are not needed in the driver.

Aside from making it easier to deal with vif type based hardware limitations,
this also makes it possible to optimize performance on hardware without native
GSO support by declaring GSO support in hw->netdev_features and removing it
from vif->netdev_features. This allows mac80211 to handle GSO segmentation
after the sta lookup, but before itxq enqueue, thus reducing the number of
unnecessary sta lookups, as well as some other per-packet processing.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20221010094338.78070-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/fq_impl: Use the bitmap API to allocate bitmaps

Use bitmap_zalloc()/bitmap_free() instead of hand-writing them.

It is less verbose and it improves the semantic.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/c7bf099af07eb497b02d195906ee8c11fea3b3bd.1657377335.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/fq_impl: do not maintain a backlog-sorted list of flows

A sorted flow list is only needed to drop packets in the biggest flow when
hitting the overmemory condition.
By scanning flows only when needed, we can avoid paying the cost of
maintaining the list under normal conditions
In order to avoid scanning lots of empty flows and touching too many cold
cache lines, a bitmap of flows with backlog is maintained

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20201218184718.93650-3-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/fq_impl: drop get_default_func, move default flow to fq_tin

Simplifies the code and prepares for a rework of scanning for flows on
overmemory drop.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20201218184718.93650-2-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/fq_impl: bulk-free packets from a flow on overmemory

This is similar to what sch_fq_codel does. It also amortizes the worst
case cost of a follow-up patch that changes the selection of the biggest
flow for dropping packets

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20201218184718.93650-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/fq_impl: use skb_get_hash instead of skb_get_hash_perturb

This avoids unnecessarily regenerating the skb flow hash

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20200726130947.88145-1-nbd@nbd.name
[small commit message fixup]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/fq_impl: Switch to kvmalloc() for memory allocation

The FQ implementation used by mac80211 allocates memory using kmalloc(),
which can fail; and Johannes reported that this actually happens in
practice.

To avoid this, switch the allocation to kvmalloc() instead; this also
brings fq_impl in line with all the FQ qdiscs.

Fixes: 557fc4a09803 ("fq: add fair queuing framework")
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20191105155750.547379-1-toke@redhat.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/flow_dissector: switch to siphash

UDP IPv6 packets auto flowlabels are using a 32bit secret
(static u32 hashrnd in net/core/flow_dissector.c) and
apply jhash() over fields known by the receivers.

Attackers can easily infer the 32bit secret and use this information
to identify a device and/or user, since this 32bit secret is only
set at boot time.

Really, using jhash() to generate cookies sent on the wire
is a serious security concern.

Trying to change the rol32(hash, 16) in ip6_make_flowlabel() would be
a dead end. Trying to periodically change the secret (like in sch_sfq.c)
could change paths taken in the network for long lived flows.

Let's switch to siphash, as we did in commit df453700e8d8
("inet: switch IP ID generator to siphash")

Using a cryptographically strong pseudo random function will solve this
privacy issue and more generally remove other weak points in the stack.

Packet schedulers using skb_get_hash_perturb() benefit from this change.

Fixes: b56774163f99 ("ipv6: Enable auto flow labels by default")
Fixes: 42240901f7c4 ("ipv6: Implement different admin modes for automatic flow labels")
Fixes: 67800f9b1f4e ("ipv6: Call skb_get_hash_flowi6 to get skb->hash in ip6_make_flowlabel")
Fixes: cb1ce2ef387b ("ipv6: Implement automatic flow label generation on transmit")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jonathan Berger <jonathann1@walla.com>
Reported-by: Amit Klein <aksecurity@gmail.com>
Reported-by: Benny Pinkas <benny@pinkas.net>
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 257

Based on 1 normalized pattern(s):

gpl v2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 19 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141333.108140152@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mac80211: calculate hash for fq without holding fq->lock in itxq enqueue

Reduces lock contention on enqueue/dequeue of iTXQ packets

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

fq_impl: Properly enforce memory limit

The fq structure would fail to properly enforce the memory limit in the case
where the packet being enqueued was bigger than the packet being removed to
bring the memory usage down. So keep dropping packets until the memory usage is
back below the limit. Also, fix the statistics for memory limit violations.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

fq: support filtering a given tin

Add to the FQ API a way to filter a given tin, in order to
remove frames that fulfil certain criteria according to a
filter function.

This will be used by mac80211 to remove frames belonging to
an AP VLAN interface that's being removed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

fq.h: Port memory limit mechanism from fq_codel

The reusable fairness queueing implementation (fq.h) lacks the memory
usage limit that the fq_codel qdisc has. This means that small
devices (e.g. WiFi routers) can run out of memory when flooded with a
large number of packets. This ports the memory limit feature from
fq_codel to fq.h.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

fq: split out backlog update logic

mac80211 (which will be the first user of the
fq.h) recently started to support software A-MSDU
aggregation. It glues skbuffs together into a
single one so the backlog accounting needs to be
more fine-grained.

To avoid backlog sorting logic duplication split
it up for re-use.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

fq: add fair queuing framework

This works on the same implementation principle as
codel*.h, i.e. there's a generic header with
structures and macros and a implementation header
carrying function definitions to include in given,
e.g. driver or module.

The fairness logic comes from
net/sched/sch_fq_codel.c but is generalized so it
is more flexible and easier to re-use.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: David S. Miller <davem@davemloft.net>