net/sched: Add module aliases for cls_,sch_,act_ modules

No functional change intended, aliases will be used in followup commits.
Note for backporters: you may need to add aliases also for modules that
are already removed in mainline kernel but still in your version.

Patches were generated with the help of Coccinelle scripts like:

cat >scripts/coccinelle/misc/tcf_alias.cocci <<EOD
virtual patch
virtual report

@ haskernel @
@@

@ tcf_has_kind depends on report && haskernel @
identifier ops;
constant K;
@@

static struct tcf_proto_ops ops = {
.kind = K,
...
};
+char module_alias = K;
EOD

/usr/bin/spatch -D report --cocci-file scripts/coccinelle/misc/tcf_alias.cocci \
--dir . \
-I ./arch/x86/include -I ./arch/x86/include/generated -I ./include \
-I ./arch/x86/include/uapi -I ./arch/x86/include/generated/uapi \
-I ./include/uapi -I ./include/generated/uapi \
--include ./include/linux/compiler-version.h --include ./include/linux/kconfig.h \
--jobs 8 --chunksize 1 2>/dev/null | \
sed 's/char module_alias = "\([^"]*\)";/MODULE_ALIAS_NET_CLS("\1");/'

And analogously for:

static struct tc_action_ops ops = {
.kind = K,

static struct Qdisc_ops ops = {
.id = K,

(Someone familiar would be able to fit those into one .cocci file
without sed post processing.)

Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240201130943.19536-3-mkoutny@suse.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/sched: introduce ACT_P_BOUND return code

Bound actions always return '0' and as of today we rely on '0'
being returned in order to properly skip bound actions in
tcf_idr_insert_many. In order to further improve maintainability,
introduce the ACT_P_BOUND return code.

Actions are updated to return 'ACT_P_BOUND' instead of plain '0'.
tcf_idr_insert_many is then updated to check for 'ACT_P_BOUND'.

Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20231229132642.1489088-1-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/sched: act_sample: fix action bind logic

The TC architecture allows filters and actions to be created independently.
In filters the user can reference action objects using:
tc action add action sample ... index 1
tc filter add ... action pedit index 1

In the current code for act_sample this is broken as it checks netlink
attributes for create/update before actually checking if we are binding to an
existing action.

tdc results:
1..29
ok 1 9784 - Add valid sample action with mandatory arguments
ok 2 5c91 - Add valid sample action with mandatory arguments and continue control action
ok 3 334b - Add valid sample action with mandatory arguments and drop control action
ok 4 da69 - Add valid sample action with mandatory arguments and reclassify control action
ok 5 13ce - Add valid sample action with mandatory arguments and pipe control action
ok 6 1886 - Add valid sample action with mandatory arguments and jump control action
ok 7 7571 - Add sample action with invalid rate
ok 8 b6d4 - Add sample action with mandatory arguments and invalid control action
ok 9 a874 - Add invalid sample action without mandatory arguments
ok 10 ac01 - Add invalid sample action without mandatory argument rate
ok 11 4203 - Add invalid sample action without mandatory argument group
ok 12 14a7 - Add invalid sample action without mandatory argument group
ok 13 8f2e - Add valid sample action with trunc argument
ok 14 45f8 - Add sample action with maximum rate argument
ok 15 ad0c - Add sample action with maximum trunc argument
ok 16 83a9 - Add sample action with maximum group argument
ok 17 ed27 - Add sample action with invalid rate argument
ok 18 2eae - Add sample action with invalid group argument
ok 19 6ff3 - Add sample action with invalid trunc size
ok 20 2b2a - Add sample action with invalid index
ok 21 dee2 - Add sample action with maximum allowed index
ok 22 560e - Add sample action with cookie
ok 23 704a - Replace existing sample action with new rate argument
ok 24 60eb - Replace existing sample action with new group argument
ok 25 2cce - Replace existing sample action with new trunc argument
ok 26 59d1 - Replace existing sample action with new control argument
ok 27 0a6e - Replace sample action with invalid goto chain control
ok 28 3872 - Delete sample action with valid index
ok 29 a394 - Delete sample action with invalid index

Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: avoid indirect act functions on retpoline kernels

Expose the necessary tc act functions and wire up act_api to use
direct calls in retpoline kernels.

Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

net: sched: act_sample: get rid of tcf_sample_walker and tcf_sample_search

tcf_sample_walker() and tcf_sample_search() do the same thing as generic
walk/search function, so remove them.

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: act: move global static variable net_id to tc_action_ops

Each tc action module has a corresponding net_id, so put net_id directly
into the structure tc_action_ops.

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: act_api: Add extack to offload_act_setup() callback

The callback is used by various actions to populate the flow action
structure prior to offload. Pass extack to this callback so that the
various actions will be able to report accurate error messages to user
space.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

flow_offload: allow user to offload tc action to net device

Use flow_indr_dev_register/flow_indr_dev_setup_offload to
offload tc action.

We need to call tc_cleanup_flow_action to clean up tc action entry since
in tc_setup_action, some actions may hold dev refcnt, especially the mirror
action.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

flow_offload: add ops to tc_action_ops for flow action setup

Add a new ops to tc_action_ops for flow action setup.

Refactor function tc_setup_flow_action to use this new ops.

We make this change to facilitate to add standalone action module.

We will also use this ops to offload action independent of filter
in following patch.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

flow_offload: fill flags to action structure

Fill flags to action structure to allow user control if
the action should be offloaded to hardware or not.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: Merge Qdisc::bstats and Qdisc::cpu_bstats data types

The only factor differentiating per-CPU bstats data type (struct
gnet_stats_basic_cpu) from the packed non-per-CPU one (struct
gnet_stats_basic_packed) was a u64_stats sync point inside the former.
The two data types are now equivalent: earlier commits added a u64_stats
sync point to the latter.

Combine both data types into "struct gnet_stats_basic_sync". This
eliminates redundancy and simplifies the bstats read/write APIs.

Use u64_stats_t for bstats "packets" and "bytes" data types. On 64-bit
architectures, u64_stats sync points do not use sequence counter
protection.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: refactor TC action init API

TC action ->init() API has 10 parameters, it becomes harder
to read. Some of them are just boolean and can be replaced
by flags. Similarly for the internal API tcf_action_init()
and tcf_exts_validate().

This patch converts them to flags and fold them into
the upper 16 bits of "flags", whose lower 16 bits are still
reserved for user-space. More specifically, the following
kernel flags are introduced:

TCA_ACT_FLAGS_POLICE replace 'name' in a few contexts, to
distinguish whether it is compatible with policer.

TCA_ACT_FLAGS_BIND replaces 'bind', to indicate whether
this action is bound to a filter.

TCA_ACT_FLAGS_REPLACE replaces 'ovr' in most contexts,
means we are replacing an existing action.

TCA_ACT_FLAGS_NO_RTNL replaces 'rtnl_held' but has the
opposite meaning, because we still hold RTNL in most
cases.

The only user-space flag TCA_ACT_FLAGS_NO_PERCPU_STATS is
untouched and still stored as before.

I have tested this patch with tdc and I do not see any
failure related to this patch.

Tested-by: Vlad Buslov <vladbu@nvidia.com>
Acked-by: Jamal Hadi Salim<jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

psample: Encapsulate packet metadata in a struct

Currently, callers of psample_sample_packet() pass three metadata
attributes: Ingress port, egress port and truncated size. Subsequent
patches are going to add more attributes (e.g., egress queue occupancy),
which also need an indication whether they are valid or not.

Encapsulate packet metadata in a struct in order to keep the number of
arguments reasonable.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sched: act_sample: Implement stats_update callback

Implement this callback in order to get the offloaded stats added to the
kernel stats.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: defer tcf_idr_insert() in tcf_action_init_1()

All TC actions call tcf_idr_insert() for new action at the end
of their ->init(), so we can actually move it to a central place
in tcf_action_init_1().

And once the action is inserted into the global IDR, other parallel
process could free it immediately as its refcnt is still 1, so we can
not fail after this, we need to move it after the goto action
validation to avoid handling the failure case after insertion.

This is found during code review, is not directly triggered by syzbot.
And this prepares for the next patch.

Cc: Vlad Buslov <vladbu@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: lock action when translating it to flow_action infra

In order to remove dependency on rtnl lock, take action's tcfa_lock when
constructing its representation as flow_action_entry structure.

Refactor tcf_sample_get_group() to assume that caller holds tcf_lock and
don't take it manually. This callback is only called from flow_action infra
representation translator which now calls it with tcf_lock held, so this
refactoring is necessary to prevent deadlock.

Allocate memory with GFP_ATOMIC flag for ip_tunnel_info copy because
tcf_tunnel_info_copy() is only called from flow_action representation infra
code with tcf_lock spinlock taken.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: update action implementations to support flags

Extend struct tc_action with new "tcfa_flags" field. Set the field in
tcf_idr_create() function and provide new helper
tcf_idr_create_from_flags() that derives 'cpustats' boolean from flags
value. Update individual hardware-offloaded actions init() to pass their
"flags" argument to new helper in order to skip percpu stats allocation
when user requested it through flags.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: extend TCA_ACT space with TCA_ACT_FLAGS

Extend TCA_ACT space with nla_bitfield32 flags. Add
TCA_ACT_FLAGS_NO_PERCPU_STATS as the only allowed flag. Parse the flags in
tcf_action_init_1() and pass resulting value as additional argument to
a_o->init().

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: Replace rcu_swap_protected() with rcu_replace_pointer()

This commit replaces the use of rcu_swap_protected() with the more
intuitively appealing rcu_replace_pointer() as a step towards removing
rcu_swap_protected().

Link: https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=Z7-GGtM6wcvtyytXZA1+BHqta4gg6Hw@mail.gmail.com/
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
[ paulmck: From rcu_replace() to rcu_replace_pointer() per Ingo Molnar. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <netdev@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>

net/sched: act_sample: don't push mac header on ip6gre ingress

current 'sample' action doesn't push the mac header of ingress packets if
they are received by a layer 3 tunnel (like gre or sit); but it forgot to
check for gre over ipv6, so the following script:

# tc q a dev $d clsact
# tc f a dev $d ingress protocol ip flower ip_proto icmp action sample \
> group 100 rate 1
# psample -v -g 100

dumps everything, including outer header and mac, when $d is a gre tunnel
over ipv6. Fix this adding a missing label for ARPHRD_IP6GRE devices.

Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Yotam Gigi <yotam.gi@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

net: sched: take reference to psample group in flow_action infra

With recent patch set that removed rtnl lock dependency from cls hardware
offload API rtnl lock is only taken when reading action data and can be
released after action-specific data is parsed into intermediate
representation. However, sample action psample group is passed by pointer
without obtaining reference to it first, which makes it possible to
concurrently overwrite the action and deallocate object pointed by
psample_group pointer after rtnl lock is released but before driver
finished using the pointer.

To prevent such race condition, obtain reference to psample group while it
is used by flow_action infra. Extend psample API with function
psample_group_take() that increments psample group reference counter.
Extend struct tc_action_ops with new get_psample_group() API. Implement the
API for action sample using psample_group_take() and already existing
psample_group_put() as a destructor. Use it in tc_setup_flow_action() to
take reference to psample group pointed to by entry->sample.psample_group
and release it in tc_cleanup_flow_action().

Disable bh when taking psample_groups_lock. The lock is now taken while
holding action tcf_lock that is used by data path and requires bh to be
disabled, so doing the same for psample_groups_lock is necessary to
preserve SOFTIRQ-irq-safety.

Fixes: 918190f50eb6 ("net: sched: flower: don't take rtnl lock for cls hw offloads API")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: act_sample: fix psample group handling on overwrite

Action sample doesn't properly handle psample_group pointer in overwrite
case. Following issues need to be fixed:

- In tcf_sample_init() function RCU_INIT_POINTER() is used to set
s->psample_group, even though we neither setting the pointer to NULL, nor
preventing concurrent readers from accessing the pointer in some way.
Use rcu_swap_protected() instead to safely reset the pointer.

- Old value of s->psample_group is not released or deallocated in any way,
which results resource leak. Use psample_group_put() on non-NULL value
obtained with rcu_swap_protected().

- The function psample_group_put() that released reference to struct
psample_group pointed by rcu-pointer s->psample_group doesn't respect rcu
grace period when deallocating it. Extend struct psample_group with rcu
head and use kfree_rcu when freeing it.

Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: fix a NULL pointer deref in ipt action

The net pointer in struct xt_tgdtor_param is not explicitly
initialized therefore is still NULL when dereferencing it.
So we have to find a way to pass the correct net pointer to
ipt_destroy_target().

The best way I find is just saving the net pointer inside the per
netns struct tcf_idrinfo, which could make this patch smaller.

Fixes: 0c66dc1ea3f0 ("netfilter: conntrack: register hooks in netns when needed by ruleset")
Reported-and-tested-by: itugrok@yahoo.com
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: use temporary variable for actions indexes

Currently init call of all actions (except ipt) init their 'parm'
structure as a direct pointer to nla data in skb. This leads to race
condition when some of the filter actions were initialized successfully
(and were assigned with idr action index that was written directly
into nla data), but then were deleted and retried (due to following
action module missing or classifier-initiated retry), in which case
action init code tries to insert action to idr with index that was
assigned on previous iteration. During retry the index can be reused
by another action that was inserted concurrently, which causes
unintended action sharing between filters.
To fix described race condition, save action idr index to temporary
stack-allocated variable instead on nla data.

Fixes: 0190c1d452a9 ("net: sched: atomically check-allocate action")
Signed-off-by: Dmytro Linkin <dmitrolin@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

netlink: make validation more configurable for future strictness

We currently have two levels of strict validation:

1) liberal (default)
- undefined (type >= max) & NLA_UNSPEC attributes accepted
- attribute length >= expected accepted
- garbage at end of message accepted
2) strict (opt-in)
- NLA_UNSPEC attributes accepted
- attribute length >= expected accepted

Split out parsing strictness into four different options:
* TRAILING - check that there's no trailing data after parsing
attributes (in message or nested)
* MAXTYPE - reject attrs > max known type
* UNSPEC - reject attributes with NLA_UNSPEC policy entries
* STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
* nla_parse -> nla_parse_deprecated
* nla_parse_strict -> nla_parse_deprecated_strict
* nlmsg_parse -> nlmsg_parse_deprecated
* nlmsg_parse_strict -> nlmsg_parse_deprecated_strict
* nla_parse_nested -> nla_parse_nested_deprecated
* nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
@@
expression TB, MAX, HEAD, LEN, POL, EXT;
@@
-nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
+nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

@@
expression TB, MAX, NLA, POL, EXT;
@@
-nla_parse_nested(TB, MAX, NLA, POL, EXT)
+nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

@@
expression START, MAX, POL, EXT;
@@
-nla_validate_nested(START, MAX, POL, EXT)
+nla_validate_nested_deprecated(START, MAX, POL, EXT)

@@
expression NLH, HDRLEN, MAX, POL, EXT;
@@
-nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
+nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: act_sample: fix divide by zero in the traffic path

the control path of 'sample' action does not validate the value of 'rate'
provided by the user, but then it uses it as divisor in the traffic path.
Validate it in tcf_sample_init(), and return -EINVAL with a proper extack
message in case that value is zero, to fix a splat with the script below:

# tc f a dev test0 egress matchall action sample rate 0 group 1 index 2
# tc -s a s action sample
total acts 1

action order 0: sample rate 1/0 group 1 pipe
index 2 ref 1 bind 1 installed 19 sec used 19 sec
Action statistics:
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
# ping 192.0.2.1 -I test0 -c1 -q

divide error: 0000 [#1] SMP PTI
CPU: 1 PID: 6192 Comm: ping Not tainted 5.1.0-rc2.diag2+ #591
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:tcf_sample_act+0x9e/0x1e0 [act_sample]
Code: 6a f1 85 c0 74 0d 80 3d 83 1a 00 00 00 0f 84 9c 00 00 00 4d 85 e4 0f 84 85 00 00 00 e8 9b d7 9c f1 44 8b 8b e0 00 00 00 31 d2 <41> f7 f1 85 d2 75 70 f6 85 83 00 00 00 10 48 8b 45 10 8b 88 08 01
RSP: 0018:ffffae320190ba30 EFLAGS: 00010246
RAX: 00000000b0677d21 RBX: ffff8af1ed9ec000 RCX: 0000000059a9fe49
RDX: 0000000000000000 RSI: 000000000c7e33b7 RDI: ffff8af23daa0af0
RBP: ffff8af1ee11b200 R08: 0000000074fcaf7e R09: 0000000000000000
R10: 0000000000000050 R11: ffffffffb3088680 R12: ffff8af232307f80
R13: 0000000000000003 R14: ffff8af1ed9ec000 R15: 0000000000000000
FS: 00007fe9c6d2f740(0000) GS:ffff8af23da80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff6772f000 CR3: 00000000746a2004 CR4: 00000000001606e0
Call Trace:
tcf_action_exec+0x7c/0x1c0
tcf_classify+0x57/0x160
__dev_queue_xmit+0x3dc/0xd10
ip_finish_output2+0x257/0x6d0
ip_output+0x75/0x280
ip_send_skb+0x15/0x40
raw_sendmsg+0xae3/0x1410
sock_sendmsg+0x36/0x40
__sys_sendto+0x10e/0x140
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x60/0x210
entry_SYSCALL_64_after_hwframe+0x49/0xbe
[...]
Kernel panic - not syncing: Fatal exception in interrupt

Add a TDC selftest to document that 'rate' is now being validated.

Reported-by: Matteo Croce <mcroce@redhat.com>
Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Yotam Gigi <yotam.gi@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: act_sample: validate the control action inside init()

the following script:

# tc qdisc add dev crash0 clsact
# tc filter add dev crash0 egress matchall \
> action sample rate 1024 group 4 pass index 90
# tc actions replace action sample \
> rate 1024 group 4 goto chain 42 index 90 cookie c1a0c1a0
# tc actions show action sample

had the following output:

Error: Failed to init TC action chain.
We have an error talking to the kernel
total acts 1

action order 0: sample rate 1/1024 group 4 goto chain 42
index 90 ref 2 bind 1
cookie c1a0c1a0

Then, the first packet transmitted by crash0 made the kernel crash:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
#PF error: [normal kernel read fault]
PGD 8000000079966067 P4D 8000000079966067 PUD 7987b067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.0.0-rc4.gotochain_crash+ #536
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:tcf_action_exec+0xb8/0x100
Code: 00 00 00 20 74 1d 83 f8 03 75 09 49 83 c4 08 4d 39 ec 75 bc 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8b 97 a8 00 00 00 <48> 8b 12 48 89 55 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3
RSP: 0018:ffffbee60033fad0 EFLAGS: 00010246
RAX: 000000002000002a RBX: ffff99d7ae6e3b00 RCX: 00000000e555df9b
RDX: 0000000000000000 RSI: 00000000b0352718 RDI: ffff99d7fda1fcf0
RBP: ffffbee60033fb70 R08: 0000000070731ab1 R09: 0000000000000400
R10: 0000000000000000 R11: ffff99d7ac733838 R12: ffff99d7f3c2be00
R13: ffff99d7f3c2be08 R14: 0000000000000001 R15: ffff99d7f3c2b600
FS: 0000000000000000(0000) GS:ffff99d7fda00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000797de006 CR4: 00000000001606f0
Call Trace:
tcf_classify+0x58/0x120
__dev_queue_xmit+0x40a/0x890
? ndisc_next_option+0x50/0x50
? ___neigh_create+0x4d5/0x680
? ip6_finish_output2+0x1b5/0x590
ip6_finish_output2+0x1b5/0x590
? ip6_output+0x68/0x110
ip6_output+0x68/0x110
? nf_hook.constprop.28+0x79/0xc0
ndisc_send_skb+0x248/0x2e0
ndisc_send_ns+0xf8/0x200
? addrconf_dad_work+0x389/0x4b0
addrconf_dad_work+0x389/0x4b0
? __switch_to_asm+0x34/0x70
? process_one_work+0x195/0x380
? addrconf_dad_completed+0x370/0x370
process_one_work+0x195/0x380
worker_thread+0x30/0x390
? process_one_work+0x380/0x380
kthread+0x113/0x130
? kthread_park+0x90/0x90
ret_from_fork+0x35/0x40
Modules linked in: act_sample psample veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel mbcache jbd2 snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device aesni_intel crypto_simd snd_pcm cryptd glue_helper snd_timer joydev snd pcspkr virtio_balloon i2c_piix4 soundcore nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect virtio_net sysimgblt fb_sys_fops net_failover ttm failover virtio_blk virtio_console drm ata_piix serio_raw crc32c_intel libata virtio_pci virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod
CR2: 0000000000000000

Validating the control action within tcf_sample_init() proved to fix the
above issue. A TDC selftest is added to verify the correct behavior.

Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: prepare TC actions to properly validate the control action

- pass a pointer to struct tcf_proto in each actions's init() handler,
to allow validating the control action, checking whether the chain
exists and (eventually) refcounting it.
- remove code that validates the control action after a successful call
to the action's init() handler, and replace it with a test that forbids
addition of actions having 'goto_chain' and NULL goto_chain pointer at
the same time.
- add tcf_action_check_ctrlact(), that will validate the control action
and eventually allocate the action 'goto_chain' within the init()
handler.
- add tcf_action_set_ctrlact(), that will assign the control action and
swap the current 'goto_chain' pointer with the new given one.

This disallows 'goto_chain' on actions that don't initialize it properly
in their init() handler, i.e. calling tcf_action_check_ctrlact() after
successful IDR reservation and then calling tcf_action_set_ctrlact()
to assign 'goto_chain' and 'tcf_action' consistently.

By doing this, the kernel does not leak anymore refcounts when a valid
'goto chain' handle is replaced in TC actions, causing kmemleak splats
like the following one:

# tc chain add dev dd0 chain 42 ingress protocol ip flower \
> ip_proto tcp action drop
# tc chain add dev dd0 chain 43 ingress protocol ip flower \
> ip_proto udp action drop
# tc filter add dev dd0 ingress matchall \
> action gact goto chain 42 index 66
# tc filter replace dev dd0 ingress matchall \
> action gact goto chain 43 index 66
# echo scan >/sys/kernel/debug/kmemleak
<...>
unreferenced object 0xffff93c0ee09f000 (size 1024):
comm "tc", pid 2565, jiffies 4295339808 (age 65.426s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 08 00 06 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000009b63f92d>] tc_ctl_chain+0x3d2/0x4c0
[<00000000683a8d72>] rtnetlink_rcv_msg+0x263/0x2d0
[<00000000ddd88f8e>] netlink_rcv_skb+0x4a/0x110
[<000000006126a348>] netlink_unicast+0x1a0/0x250
[<00000000b3340877>] netlink_sendmsg+0x2c1/0x3c0
[<00000000a25a2171>] sock_sendmsg+0x36/0x40
[<00000000f19ee1ec>] ___sys_sendmsg+0x280/0x2f0
[<00000000d0422042>] __sys_sendmsg+0x5e/0xa0
[<000000007a6c61f9>] do_syscall_64+0x5b/0x180
[<00000000ccd07542>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[<0000000013eaa334>] 0xffffffffffffffff

Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f401 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Change TCA_ACT_* to TCA_ID_* to match that of TCA_ID_POLICE

Modify the kernel users of the TCA_ACT_* macros to use TCA_ID_*. For
example, use TCA_ID_GACT instead of TCA_ACT_GACT. This will align with
TCA_ID_POLICE and also differentiates these identifier, used in struct
tc_action_ops type field, from other macros starting with TCA_ACT_.

To make things clearer, we name the enum defining the TCA_ID_*
identifiers and also change the "type" field of struct tc_action to
id.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: act_sample: fix NULL dereference in the data path

Matteo reported the following splat, testing the datapath of TC 'sample':

BUG: KASAN: null-ptr-deref in tcf_sample_act+0xc4/0x310
Read of size 8 at addr 0000000000000000 by task nc/433

CPU: 0 PID: 433 Comm: nc Not tainted 4.19.0-rc3-kvm #17
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180531_142017-buildhw-08.phx2.fedoraproject.org-1.fc28 04/01/2014
Call Trace:
kasan_report.cold.6+0x6c/0x2fa
tcf_sample_act+0xc4/0x310
? dev_hard_start_xmit+0x117/0x180
tcf_action_exec+0xa3/0x160
tcf_classify+0xdd/0x1d0
htb_enqueue+0x18e/0x6b0
? deref_stack_reg+0x7a/0xb0
? htb_delete+0x4b0/0x4b0
? unwind_next_frame+0x819/0x8f0
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
__dev_queue_xmit+0x722/0xca0
? unwind_get_return_address_ptr+0x50/0x50
? netdev_pick_tx+0xe0/0xe0
? save_stack+0x8c/0xb0
? kasan_kmalloc+0xbe/0xd0
? __kmalloc_track_caller+0xe4/0x1c0
? __kmalloc_reserve.isra.45+0x24/0x70
? __alloc_skb+0xdd/0x2e0
? sk_stream_alloc_skb+0x91/0x3b0
? tcp_sendmsg_locked+0x71b/0x15a0
? tcp_sendmsg+0x22/0x40
? __sys_sendto+0x1b0/0x250
? __x64_sys_sendto+0x6f/0x80
? do_syscall_64+0x5d/0x150
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
? __sys_sendto+0x1b0/0x250
? __x64_sys_sendto+0x6f/0x80
? do_syscall_64+0x5d/0x150
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
ip_finish_output2+0x495/0x590
? ip_copy_metadata+0x2e0/0x2e0
? skb_gso_validate_network_len+0x6f/0x110
? ip_finish_output+0x174/0x280
__tcp_transmit_skb+0xb17/0x12b0
? __tcp_select_window+0x380/0x380
tcp_write_xmit+0x913/0x1de0
? __sk_mem_schedule+0x50/0x80
tcp_sendmsg_locked+0x49d/0x15a0
? tcp_rcv_established+0x8da/0xa30
? tcp_set_state+0x220/0x220
? clear_user+0x1f/0x50
? iov_iter_zero+0x1ae/0x590
? __fget_light+0xa0/0xe0
tcp_sendmsg+0x22/0x40
__sys_sendto+0x1b0/0x250
? __ia32_sys_getpeername+0x40/0x40
? _copy_to_user+0x58/0x70
? poll_select_copy_remaining+0x176/0x200
? __pollwait+0x1c0/0x1c0
? ktime_get_ts64+0x11f/0x140
? kern_select+0x108/0x150
? core_sys_select+0x360/0x360
? vfs_read+0x127/0x150
? kernel_write+0x90/0x90
__x64_sys_sendto+0x6f/0x80
do_syscall_64+0x5d/0x150
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fefef2b129d
Code: ff ff ff ff eb b6 0f 1f 80 00 00 00 00 48 8d 05 51 37 0c 00 41 89 ca 8b 00 85 c0 75 20 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 6b f3 c3 66 0f 1f 84 00 00 00 00 00 41 56 41
RSP: 002b:00007fff2f5350c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000056118d60c120 RCX: 00007fefef2b129d
RDX: 0000000000002000 RSI: 000056118d629320 RDI: 0000000000000003
RBP: 000056118d530370 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000002000
R13: 000056118d5c2a10 R14: 000056118d5c2a10 R15: 000056118d5303b8

tcf_sample_act() tried to update its per-cpu stats, but tcf_sample_init()
forgot to allocate them, because tcf_idr_create() was called with a wrong
value of 'cpustats'. Setting it to true proved to fix the reported crash.

Reported-by: Matteo Croce <mcroce@redhat.com>
Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR")
Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Tested-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "net: sched: act: add extack for lookup callback"

This reverts commit 331a9295de23 ("net: sched: act: add extack for lookup callback").

This extack is never used after 6 months... In fact, it can be just
set in the caller, right after ->lookup().

Cc: Alexander Aring <aring@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: remove unnecessary ops->delete()

All ops->delete() wants is getting the tn->idrinfo, but we already
have tc_action before calling ops->delete(), and tc_action has
a pointer ->idrinfo.

More importantly, each type of action does the same thing, that is,
just calling tcf_idr_delete_index().

So it can be just removed.

Fixes: b409074e6693 ("net: sched: add 'delete' function to action ops")
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: always disable bh when taking tcf_lock

Recently, ops->init() and ops->dump() of all actions were modified to
always obtain tcf_lock when accessing private action state. Actions that
don't depend on tcf_lock for synchronization with their data path use
non-bh locking API. However, tcf_lock is also used to protect rate
estimator stats in softirq context by timer callback.

Change ops->init() and ops->dump() of all actions to disable bh when using
tcf_lock to prevent deadlock reported by following lockdep warning:

[ 105.470398] ================================
[ 105.475014] WARNING: inconsistent lock state
[ 105.479628] 4.18.0-rc8+ #664 Not tainted
[ 105.483897] --------------------------------
[ 105.488511] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[ 105.494871] swapper/16/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[ 105.500449] 00000000f86c012e (&(&p->tcfa_lock)->rlock){+.?.}, at: est_fetch_counters+0x3c/0xa0
[ 105.509696] {SOFTIRQ-ON-W} state was registered at:
[ 105.514925] _raw_spin_lock+0x2c/0x40
[ 105.519022] tcf_bpf_init+0x579/0x820 [act_bpf]
[ 105.523990] tcf_action_init_1+0x4e4/0x660
[ 105.528518] tcf_action_init+0x1ce/0x2d0
[ 105.532880] tcf_exts_validate+0x1d8/0x200
[ 105.537416] fl_change+0x55a/0x268b [cls_flower]
[ 105.542469] tc_new_tfilter+0x748/0xa20
[ 105.546738] rtnetlink_rcv_msg+0x56a/0x6d0
[ 105.551268] netlink_rcv_skb+0x18d/0x200
[ 105.555628] netlink_unicast+0x2d0/0x370
[ 105.559990] netlink_sendmsg+0x3b9/0x6a0
[ 105.564349] sock_sendmsg+0x6b/0x80
[ 105.568271] ___sys_sendmsg+0x4a1/0x520
[ 105.572547] __sys_sendmsg+0xd7/0x150
[ 105.576655] do_syscall_64+0x72/0x2c0
[ 105.580757] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 105.586243] irq event stamp: 489296
[ 105.590084] hardirqs last enabled at (489296): [<ffffffffb507e639>] _raw_spin_unlock_irq+0x29/0x40
[ 105.599765] hardirqs last disabled at (489295): [<ffffffffb507e745>] _raw_spin_lock_irq+0x15/0x50
[ 105.609277] softirqs last enabled at (489292): [<ffffffffb413a6a3>] irq_enter+0x83/0xa0
[ 105.618001] softirqs last disabled at (489293): [<ffffffffb413a800>] irq_exit+0x140/0x190
[ 105.626813]
other info that might help us debug this:
[ 105.633976] Possible unsafe locking scenario:

[ 105.640526] CPU0
[ 105.643325] ----
[ 105.646125] lock(&(&p->tcfa_lock)->rlock);
[ 105.650747] <Interrupt>
[ 105.653717] lock(&(&p->tcfa_lock)->rlock);
[ 105.658514]
*** DEADLOCK ***

[ 105.665349] 1 lock held by swapper/16/0:
[ 105.669629] #0: 00000000a640ad99 ((&est->timer)){+.-.}, at: call_timer_fn+0x10b/0x550
[ 105.678200]
stack backtrace:
[ 105.683194] CPU: 16 PID: 0 Comm: swapper/16 Not tainted 4.18.0-rc8+ #664
[ 105.690249] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017
[ 105.698626] Call Trace:
[ 105.701421] <IRQ>
[ 105.703791] dump_stack+0x92/0xeb
[ 105.707461] print_usage_bug+0x336/0x34c
[ 105.711744] mark_lock+0x7c9/0x980
[ 105.715500] ? print_shortest_lock_dependencies+0x2e0/0x2e0
[ 105.721424] ? check_usage_forwards+0x230/0x230
[ 105.726315] __lock_acquire+0x923/0x26f0
[ 105.730597] ? debug_show_all_locks+0x240/0x240
[ 105.735478] ? mark_lock+0x493/0x980
[ 105.739412] ? check_chain_key+0x140/0x1f0
[ 105.743861] ? __lock_acquire+0x836/0x26f0
[ 105.748323] ? lock_acquire+0x12e/0x290
[ 105.752516] lock_acquire+0x12e/0x290
[ 105.756539] ? est_fetch_counters+0x3c/0xa0
[ 105.761084] _raw_spin_lock+0x2c/0x40
[ 105.765099] ? est_fetch_counters+0x3c/0xa0
[ 105.769633] est_fetch_counters+0x3c/0xa0
[ 105.773995] est_timer+0x87/0x390
[ 105.777670] ? est_fetch_counters+0xa0/0xa0
[ 105.782210] ? lock_acquire+0x12e/0x290
[ 105.786410] call_timer_fn+0x161/0x550
[ 105.790512] ? est_fetch_counters+0xa0/0xa0
[ 105.795055] ? del_timer_sync+0xd0/0xd0
[ 105.799249] ? __lock_is_held+0x93/0x110
[ 105.803531] ? mark_held_locks+0x20/0xe0
[ 105.807813] ? _raw_spin_unlock_irq+0x29/0x40
[ 105.812525] ? est_fetch_counters+0xa0/0xa0
[ 105.817069] ? est_fetch_counters+0xa0/0xa0
[ 105.821610] run_timer_softirq+0x3c4/0x9f0
[ 105.826064] ? lock_acquire+0x12e/0x290
[ 105.830257] ? __bpf_trace_timer_class+0x10/0x10
[ 105.835237] ? __lock_is_held+0x25/0x110
[ 105.839517] __do_softirq+0x11d/0x7bf
[ 105.843542] irq_exit+0x140/0x190
[ 105.847208] smp_apic_timer_interrupt+0xac/0x3b0
[ 105.852182] apic_timer_interrupt+0xf/0x20
[ 105.856628] </IRQ>
[ 105.859081] RIP: 0010:cpuidle_enter_state+0xd8/0x4d0
[ 105.864395] Code: 46 ff 48 89 44 24 08 0f 1f 44 00 00 31 ff e8 cf ec 46 ff 80 7c 24 07 00 0f 85 1d 02 00 00 e8 9f 90 4b ff fb 66 0f 1f 44 00 00 <4c> 8b 6c 24 08 4d 29 fd 0f 80 36 03 00 00 4c 89 e8 48 ba cf f7 53
[ 105.884288] RSP: 0018:ffff8803ad94fd20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
[ 105.892494] RAX: 0000000000000000 RBX: ffffe8fb300829c0 RCX: ffffffffb41e19e1
[ 105.899988] RDX: 0000000000000007 RSI: dffffc0000000000 RDI: ffff8803ad9358ac
[ 105.907503] RBP: ffffffffb6636300 R08: 0000000000000004 R09: 0000000000000000
[ 105.914997] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000004
[ 105.922487] R13: ffffffffb6636140 R14: ffffffffb66362d8 R15: 000000188d36091b
[ 105.929988] ? trace_hardirqs_on_caller+0x141/0x2d0
[ 105.935232] do_idle+0x28e/0x320
[ 105.938817] ? arch_cpu_idle_exit+0x40/0x40
[ 105.943361] ? mark_lock+0x8c1/0x980
[ 105.947295] ? _raw_spin_unlock_irqrestore+0x32/0x60
[ 105.952619] cpu_startup_entry+0xc2/0xd0
[ 105.956900] ? cpu_in_idle+0x20/0x20
[ 105.960830] ? _raw_spin_unlock_irqrestore+0x32/0x60
[ 105.966146] ? trace_hardirqs_on_caller+0x141/0x2d0
[ 105.971391] start_secondary+0x2b5/0x360
[ 105.975669] ? set_cpu_sibling_map+0x1330/0x1330
[ 105.980654] secondary_startup_64+0xa5/0xb0

Taking tcf_lock in sample action with bh disabled causes lockdep to issue a
warning regarding possible irq lock inversion dependency between tcf_lock,
and psample_groups_lock that is taken when holding tcf_lock in sample init:

[ 162.108959] Possible interrupt unsafe locking scenario:

[ 162.116386] CPU0 CPU1
[ 162.121277] ---- ----
[ 162.126162] lock(psample_groups_lock);
[ 162.130447] local_irq_disable();
[ 162.136772] lock(&(&p->tcfa_lock)->rlock);
[ 162.143957] lock(psample_groups_lock);
[ 162.150813] <Interrupt>
[ 162.153808] lock(&(&p->tcfa_lock)->rlock);
[ 162.158608]
*** DEADLOCK ***

In order to prevent potential lock inversion dependency between tcf_lock
and psample_groups_lock, extract call to psample_group_get() from tcf_lock
protected section in sample action init function.

Fixes: 4e232818bd32 ("net: sched: act_mirred: remove dependency on rtnl lock")
Fixes: 764e9a24480f ("net: sched: act_vlan: remove dependency on rtnl lock")
Fixes: 729e01260989 ("net: sched: act_tunnel_key: remove dependency on rtnl lock")
Fixes: d77284956656 ("net: sched: act_sample: remove dependency on rtnl lock")
Fixes: e8917f437006 ("net: sched: act_gact: remove dependency on rtnl lock")
Fixes: b6a2b971c0b0 ("net: sched: act_csum: remove dependency on rtnl lock")
Fixes: 2142236b4584 ("net: sched: act_bpf: remove dependency on rtnl lock")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: act_sample: remove dependency on rtnl lock

Use tcf spinlock to protect private sample action data from concurrent
modification during dump and init.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tc/act: remove unneeded RCU lock in action callback

Each lockless action currently does its own RCU locking in ->act().
This allows using plain RCU accessor, even if the context
is really RCU BH.

This change drops the per action RCU lock, replace the accessors
with the _bh variant, cleans up a bit the surrounding code and
documents the RCU status in the relevant header.
No functional nor performance change is intended.

The goal of this patch is clarifying that the RCU critical section
used by the tc actions extends up to the classifier's caller.

v1 -> v2:
- preserve rcu lock in act_bpf: it's needed by eBPF helpers,
as pointed out by Daniel

v3 -> v4:
- fixed some typos in the commit message (JiriP)

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: atomically check-allocate action

Implement function that atomically checks if action exists and either takes
reference to it, or allocates idr slot for action index to prevent
concurrent allocations of actions with same index. Use EBUSY error pointer
to indicate that idr slot is reserved.

Implement cleanup helper function that removes temporary error pointer from
idr. (in case of error between idr allocation and insertion of newly
created action to specified index)

Refactor all action init functions to insert new action to idr using this
API.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: don't release reference on action overwrite

Return from action init function with reference to action taken,
even when overwriting existing action.

Action init API initializes its fourth argument (pointer to pointer to tc
action) to either existing action with same index or newly created action.
In case of existing index(and bind argument is zero), init function returns
without incrementing action reference counter. Caller of action init then
proceeds working with action, without actually holding reference to it.
This means that action could be deleted concurrently.

Change action init behavior to always take reference to action before
returning successfully, in order to protect from concurrent deletion.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: add 'delete' function to action ops

Extend action ops with 'delete' function. Each action type to implements
its own delete function that doesn't depend on rtnl lock.

Implement delete function that is required to delete actions without
holding rtnl lock. Use action API function that atomically deletes action
only if it is still in action idr. This implementation prevents concurrent
threads from deleting same action twice.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: implement unlocked action init API

Add additional 'rtnl_held' argument to act API init functions. It is
required to implement actions that need to release rtnl lock before loading
kernel module and reacquire if afterwards.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: change type of reference and bind counters

Change type of action reference counter to refcount_t.

Change type of action bind counter to atomic_t.
This type is used to allow decrementing bind counter without testing
for 0 result.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Drop pernet_operations::async

Synchronous pernet_operations are not allowed anymore.
All are asynchronous. So, drop the structure member.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: fix NULL dereference in the error path of tcf_sample_init()

when the following command

# tc action add action sample rate 100 group 100 index 100

is run for the first time, and psample_group_get(100) fails to create a
new group, tcf_sample_cleanup() calls psample_group_put(NULL), thus
causing the following error:

BUG: unable to handle kernel NULL pointer dereference at 000000000000001c
IP: psample_group_put+0x15/0x71 [psample]
PGD 8000000075775067 P4D 8000000075775067 PUD 7453c067 PMD 0
Oops: 0002 [#1] SMP PTI
Modules linked in: act_sample(E) psample ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hda_core mbcache jbd2 crct10dif_pclmul snd_hwdep crc32_pclmul snd_seq ghash_clmulni_intel pcbc snd_seq_device snd_pcm aesni_intel crypto_simd snd_timer glue_helper snd cryptd joydev pcspkr i2c_piix4 soundcore virtio_balloon nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm virtio_net ata_piix virtio_console virtio_blk libata serio_raw crc32c_intel virtio_pci i2c_core virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod [last unloaded: act_tunnel_key]
CPU: 2 PID: 5740 Comm: tc Tainted: G E 4.16.0-rc4.act_vlan.orig+ #403
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:psample_group_put+0x15/0x71 [psample]
RSP: 0018:ffffb8a80032f7d0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000024
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffffffc06d93c0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044
R10: 00000000bd003000 R11: ffff979fba04aa59 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff979fbba3f22c
FS: 00007f7638112740(0000) GS:ffff979fbfd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000001c CR3: 00000000734ea001 CR4: 00000000001606e0
Call Trace:
__tcf_idr_release+0x79/0xf0
tcf_sample_init+0x125/0x1d0 [act_sample]
tcf_action_init_1+0x2cc/0x430
tcf_action_init+0xd3/0x1b0
tc_ctl_action+0x18b/0x240
rtnetlink_rcv_msg+0x29c/0x310
? _cond_resched+0x15/0x30
? __kmalloc_node_track_caller+0x1b9/0x270
? rtnl_calcit.isra.28+0x100/0x100
netlink_rcv_skb+0xd2/0x110
netlink_unicast+0x17c/0x230
netlink_sendmsg+0x2cd/0x3c0
sock_sendmsg+0x30/0x40
___sys_sendmsg+0x27a/0x290
? filemap_map_pages+0x34a/0x3a0
? __handle_mm_fault+0xbfd/0xe20
__sys_sendmsg+0x51/0x90
do_syscall_64+0x6e/0x1a0
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x7f7637523ba0
RSP: 002b:00007fff0473ef58 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fff0473f080 RCX: 00007f7637523ba0
RDX: 0000000000000000 RSI: 00007fff0473efd0 RDI: 0000000000000003
RBP: 000000005aaaac80 R08: 0000000000000002 R09: 0000000000000000
R10: 00007fff0473e9e0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff0473f094 R14: 0000000000000001 R15: 0000000000669f60
Code: be 02 00 00 00 48 89 df e8 a9 fe ff ff e9 7c ff ff ff 0f 1f 40 00 0f 1f 44 00 00 53 48 89 fb 48 c7 c7 c0 93 6d c0 e8 db 20 8c ef <83> 6b 1c 01 74 10 48 c7 c7 c0 93 6d c0 ff 14 25 e8 83 83 b0 5b
RIP: psample_group_put+0x15/0x71 [psample] RSP: ffffb8a80032f7d0
CR2: 000000000000001c

Fix it in tcf_sample_cleanup(), ensuring that calls to psample_group_put(p)
are done only when p is not NULL.

Fixes: cadb9c9fdbc6 ("net/sched: act_sample: Fix error path in init")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Convert tc_action_net_init() and tc_action_net_exit() based pernet_operations

These pernet_operations are from net/sched directory, and they call only
tc_action_net_init() and tc_action_net_exit():

bpf_net_ops
connmark_net_ops
csum_net_ops
gact_net_ops
ife_net_ops
ipt_net_ops
xt_net_ops
mirred_net_ops
nat_net_ops
pedit_net_ops
police_net_ops
sample_net_ops
simp_net_ops
skbedit_net_ops
skbmod_net_ops
tunnel_key_net_ops
vlan_net_ops

1)tc_action_net_init() just allocates and initializes per-net memory.
2)There should not be in-flight packets at the time of tc_action_net_exit()
call, or another pernet_operations send packets to dying net (except
netlink). So, it seems they can be marked as async.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: act: handle extack in tcf_generic_walker

This patch adds extack handling for a common used TC act function
"tcf_generic_walker()" to add an extack message on failures.
The tcf_generic_walker() function can fail if get a invalid command
different than DEL and GET. The naming "action" here is wrong, the
correct naming would be command.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: act: add extack for walk callback

This patch adds extack support for act walker callback api. This
prepares to handle extack support inside each specific act
implementation.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: act: add extack for lookup callback

This patch adds extack support for act lookup callback api. This
prepares to handle extack support inside each specific act
implementation.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: sched: act: add extack to init callback

This patch adds extack support for act init callback api. This
prepares to handle extack support inside each specific act
implementation.

Based on work by David Ahern <dsahern@gmail.com>

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: switch to exit_batch for action pernet ops

Since we now hold RTNL lock in tc_action_net_exit(), it is good to
batch them to speedup tc action dismantle.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: remove unused parameter from act cleanup ops

No one actually uses it.

Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

act_sample: get rid of tcf_sample_cleanup_rcu()

Similar to commit d7fb60b9cafb ("net_sched: get rid of tcfa_rcu"),
TC actions don't need to respect RCU grace period, because it
is either just detached from tc filter (standalone case) or
it is removed together with tc filter (bound case) in which case
RCU grace period is already respected at filter layer.

Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Revert "net_sched: hold netns refcnt for each action"

This reverts commit ceffcc5e254b450e6159f173e4538215cebf1b59.
If we hold that refcnt, the netns can never be destroyed until
all actions are destroyed by user, this breaks our netns design
which we expect all actions are destroyed when we destroy the
whole netns.

Cc: Lucas Bates <lucasb@mojatatu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: hold netns refcnt for each action

TC actions have been destroyed asynchronously for a long time,
previously in a RCU callback and now in a workqueue. If we
don't hold a refcnt for its netns, we could use the per netns
data structure, struct tcf_idrinfo, after it has been freed by
netns workqueue.

Hold refcnt to ensure netns destroy happens after all actions
are gone.

Fixes: ddf97ccdd7cb ("net_sched: add network namespace support for tc actions")
Reported-by: Lucas Bates <lucasb@mojatatu.com>
Tested-by: Lucas Bates <lucasb@mojatatu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS: Update Yotam's E-mail

For the time being I will be available in my private mail. Update both the
MAINTAINERS file and the individual modules MODULE_AUTHOR directive with
the new address.

Signed-off-by: Yotam Gigi <yotam.gi@gmail.com>
Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net_sched: fix call_rcu() race on act_sample module removal

Similar to commit c78e1746d3ad
("net: sched: fix call_rcu() race on classifier module unloads"),
we need to wait for flying RCU callback tcf_sample_cleanup_rcu().

Cc: Yotam Gigi <yotamg@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: Change act_api and act_xxx modules to use IDR

Typically, each TC filter has its own action. All the actions of the
same type are saved in its hash table. But the hash buckets are too
small that it degrades to a list. And the performance is greatly
affected. For example, it takes about 0m11.914s to insert 64K rules.
If we convert the hash table to IDR, it only takes about 0m1.500s.
The improvement is huge.

But please note that the test result is based on previous patch that
cls_flower uses IDR.

Signed-off-by: Chris Mi <chrism@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: pass extended ACK struct to parsing functions

Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: act_psample: Remove unnecessary ASSERT_RTNL

The ASSERT_RTNL is not necessary in the init function, as it does not
touch any rtnl protected structures, as opposed to the mirred action which
does have to hold a net device.

Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: act_sample: Fix error path in init

Fix error path of in sample init, by releasing the tc hash in case of
failure in psample_group creation.

Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched: Introduce sample tc action

This action allows the user to sample traffic matched by tc classifier.
The sampling consists of choosing packets randomly and sampling them using
the psample module. The user can configure the psample group number, the
sampling rate and the packet's truncation (to save kernel-user traffic).

Example:
To sample ingress traffic from interface eth1, one may use the commands:

tc qdisc add dev eth1 handle ffff: ingress

tc filter add dev eth1 parent ffff: \
matchall action sample rate 12 group 4

Where the first command adds an ingress qdisc and the second starts
sampling randomly with an average of one sampled packet per 12 packets on
dev eth1 to psample group 4.

Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>