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Move drop_reason from struct tcf_result to skb cb - more specifically to
struct tc_skb_cb. With that, we'll be able to also set the drop reason for
the remaining qdiscs (aside from clsact) that do not have access to
tcf_result when time comes to set the skb drop reason.
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcf_idr_insert_many will replace the allocated -EBUSY pointer in
tcf_idr_check_alloc with the real action pointer, exposing it
to all operations. This operation is only needed when the action pointer
is created (ACT_P_CREATED). For actions which are bound to (returned 0),
the pointer already resides in the idr making such operation a nop.
Even though it's a nop, it's still not a cheap operation as internally
the idr code walks the idr and then does a replace on the appropriate slot.
So if the action was bound, better skip the idr replace entirely.
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Vlad Buslov <vladbu@nvidia.com>
Link: https://lore.kernel.org/r/20231211181807.96028-3-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Instead of relying only on the idrinfo->lock mutex for
bind/alloc logic, rely on a combination of rcu + mutex + atomics
to better scale the case where multiple rtnl-less filters are
binding to the same action object.
Action binding happens when an action index is specified explicitly and
an action exists which such index exists. Example:
tc actions add action drop index 1
tc filter add ... matchall action drop index 1
tc filter add ... matchall action drop index 1
tc filter add ... matchall action drop index 1
tc filter ls ...
filter protocol all pref 49150 matchall chain 0 filter protocol all pref 49150 matchall chain 0 handle 0x1
not_in_hw
action order 1: gact action drop
random type none pass val 0
index 1 ref 4 bind 3
filter protocol all pref 49151 matchall chain 0 filter protocol all pref 49151 matchall chain 0 handle 0x1
not_in_hw
action order 1: gact action drop
random type none pass val 0
index 1 ref 4 bind 3
filter protocol all pref 49152 matchall chain 0 filter protocol all pref 49152 matchall chain 0 handle 0x1
not_in_hw
action order 1: gact action drop
random type none pass val 0
index 1 ref 4 bind 3
When no index is specified, as before, grab the mutex and allocate
in the idr the next available id. In this version, as opposed to before,
it's simplified to store the -EBUSY pointer instead of the previous
alloc + replace combination.
When an index is specified, rely on rcu to find if there's an object in
such index. If there's none, fallback to the above, serializing on the
mutex and reserving the specified id. If there's one, it can be an -EBUSY
pointer, in which case we just try again until it's an action, or an action.
Given the rcu guarantees, the action found could be dead and therefore
we need to bump the refcount if it's not 0, handling the case it's
in fact 0.
As bind and the action refcount are already atomics, these increments can
happen without the mutex protection while many tcf_idr_check_alloc race
to bind to the same action instance.
In case binding encounters a parallel delete or add, it will return
-EAGAIN in order to try again. Both filter and action apis already
have the retry machinery in-place. In case it's an unlocked filter it
retries under the rtnl lock.
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Vlad Buslov <vladbu@nvidia.com>
Link: https://lore.kernel.org/r/20231211181807.96028-2-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As of today tc-action events are unconditionally built and sent to
RTNLGRP_TC. As with the introduction of rtnl_notify_needed we can check
before-hand if they are really needed.
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231208192847.714940-6-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use max() in a couple of places that are open coding it with the
ternary operator.
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231208192847.714940-5-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The actions array is contiguous, so stop processing whenever a NULL
is found. This is already the assumption for tcf_action_destroy[1],
which is called from tcf_actions_init.
[1] https://elixir.bootlin.com/linux/v6.7-rc3/source/net/sched/act_api.c#L1115
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The ops array is contiguous, so stop processing whenever a NULL is found
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
In tcf_action_add, when putting the reference for the bound actions
it assigns NULLs to just created actions passing a non contiguous
array to tcf_action_put_many.
Refactor the code so the actions array is always contiguous.
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Use the auxiliary macro tcf_act_for_each_action in all the
functions that expect a contiguous action array
Suggested-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Getting the following splat [1] with CONFIG_DEBUG_NET=y and this
reproducer [2]. Problem seems to be that classifiers clear 'struct
tcf_result::drop_reason', thereby triggering the warning in
__kfree_skb_reason() due to reason being 'SKB_NOT_DROPPED_YET' (0).
Fixed by disambiguating a legit error from a verdict with a bogus drop_reason
[1]
WARNING: CPU: 0 PID: 181 at net/core/skbuff.c:1082 kfree_skb_reason+0x38/0x130
Modules linked in:
CPU: 0 PID: 181 Comm: mausezahn Not tainted 6.6.0-rc6-custom-ge43e6d9582e0 #682
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc37 04/01/2014
RIP: 0010:kfree_skb_reason+0x38/0x130
[...]
Call Trace:
<IRQ>
__netif_receive_skb_core.constprop.0+0x837/0xdb0
__netif_receive_skb_one_core+0x3c/0x70
process_backlog+0x95/0x130
__napi_poll+0x25/0x1b0
net_rx_action+0x29b/0x310
__do_softirq+0xc0/0x29b
do_softirq+0x43/0x60
</IRQ>
[2]
ip link add name veth0 type veth peer name veth1
ip link set dev veth0 up
ip link set dev veth1 up
tc qdisc add dev veth1 clsact
tc filter add dev veth1 ingress pref 1 proto all flower dst_mac 00:11:22:33:44:55 action drop
mausezahn veth0 -a own -b 00:11:22:33:44:55 -q -c 1
Ido reported:
[...] getting the following splat [1] with CONFIG_DEBUG_NET=y and this
reproducer [2]. Problem seems to be that classifiers clear 'struct
tcf_result::drop_reason', thereby triggering the warning in
__kfree_skb_reason() due to reason being 'SKB_NOT_DROPPED_YET' (0). [...]
[1]
WARNING: CPU: 0 PID: 181 at net/core/skbuff.c:1082 kfree_skb_reason+0x38/0x130
Modules linked in:
CPU: 0 PID: 181 Comm: mausezahn Not tainted 6.6.0-rc6-custom-ge43e6d9582e0 #682
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc37 04/01/2014
RIP: 0010:kfree_skb_reason+0x38/0x130
[...]
Call Trace:
<IRQ>
__netif_receive_skb_core.constprop.0+0x837/0xdb0
__netif_receive_skb_one_core+0x3c/0x70
process_backlog+0x95/0x130
__napi_poll+0x25/0x1b0
net_rx_action+0x29b/0x310
__do_softirq+0xc0/0x29b
do_softirq+0x43/0x60
</IRQ>
[2]
#!/bin/bash
ip link add name veth0 type veth peer name veth1
ip link set dev veth0 up
ip link set dev veth1 up
tc qdisc add dev veth1 clsact
tc filter add dev veth1 ingress pref 1 proto all flower dst_mac 00:11:22:33:44:55 action drop
mausezahn veth0 -a own -b 00:11:22:33:44:55 -q -c 1
What happens is that inside most classifiers the tcf_result is copied over
from a filter template e.g. *res = f->res which then implicitly overrides
the prior SKB_DROP_REASON_TC_{INGRESS,EGRESS} default drop code which was
set via sch_handle_{ingress,egress}() for kfree_skb_reason().
Commit text above copied verbatim from Daniel. The general idea of the patch
is not very different from what Ido originally posted but instead done at the
cls_api codepath.
Fixes: 54a59aed395c ("net, sched: Make tc-related drop reason more flexible")
Reported-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/netdev/ZTjY959R+AFXf3Xy@shredder
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
Direct replacement is safe here since return value of -errno
is used to check for truncation instead of sizeof(dest).
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
4 places in the act api code are using 'TCA_' definitions where they
should be using 'TCA_ACT_', which is confusing for the reader, although
functionally they are equivalent.
Cc: Hangbin Liu <haliu@redhat.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Hangbin Liu <haliu@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In my previous commit 0349b8779cc9 ("sched: add new attr TCA_EXT_WARN_MSG
to report tc extact message") I didn't notice the tc action use different
enum with filter. So we can't use TCA_EXT_WARN_MSG directly for tc action.
Let's add a TCA_ROOT_EXT_WARN_MSG for tc action specifically and put this
param before going to the TCA_ACT_TAB nest.
Fixes: 0349b8779cc9 ("sched: add new attr TCA_EXT_WARN_MSG to report tc extact message")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This reverts commit 923b2e30dc9cd05931da0f64e2e23d040865c035.
This is not a correct fix as TCA_EXT_WARN_MSG is not a hierarchy to
TCA_ACT_TAB. I didn't notice the TC actions use different enum when adding
TCA_EXT_WARN_MSG. To fix the difference I will add a new WARN enum in
TCA_ROOT_MAX as Jamal suggested.
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
TCA_EXT_WARN_MSG is currently sitting outside of the expected hierarchy
for the tc actions code. It should sit within TCA_ACT_TAB.
Fixes: 0349b8779cc9 ("sched: add new attr TCA_EXT_WARN_MSG to report tc extact message")
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>
For drivers to support partial offload of a filter's action list,
add support for action miss to specify an action instance to
continue from in sw.
CT action in particular can't be fully offloaded, as new connections
need to be handled in software. This imposes other limitations on
the actions that can be offloaded together with the CT action, such
as packet modifications.
Assign each action on a filter's action list a unique miss_cookie
which drivers can then use to fill action_miss part of the tc skb
extension. On getting back this miss_cookie, find the action
instance with relevant cookie and continue classifying from there.
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
struct tc_action->act_cookie is a user defined cookie,
and the related struct flow_action_entry->act_cookie is
used as an handle similar to struct flow_cls_offload->cookie.
Rename tc_action->act_cookie to user_cookie, and
flow_action_entry->act_cookie to cookie so their names
would better fit their usage.
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There are currently two mechanisms for populating hardware stats:
1. Using flow_offload api to query the flow's statistics.
The api assumes that the same stats values apply to all
the flow's actions.
This assumption breaks when action drops or jumps over following
actions.
2. Using hw_action api to query specific action stats via a driver
callback method. This api assures the correct action stats for
the offloaded action, however, it does not apply to the rest of the
actions in the flow's actions array.
Extend the flow_offload stats callback to indicate that a per action
stats update is required.
Use the existing flow_offload_action api to query the action's hw stats.
In addition, currently the tc action stats utility only updates hw actions.
Reuse the existing action stats cb infrastructure to query any action
stats.
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Currently a hardware action is uniquely identified by the <id, hw_index>
tuple. However, the id is set by the flow_act_setup callback and tc core
cannot enforce this, and it is possible that a future change could break
this. In addition, <id, hw_index> are not unique across network namespaces.
Uniquely identify the action by setting an action cookie by the tc core.
Use the unique action cookie to query the action's hardware stats.
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Currently the hw action stats update is called from tcf_exts_hw_stats_update,
when a tc filter is dumped, and from tcf_action_copy_stats, when a hw
action is dumped.
However, the tcf_action_copy_stats is also called from tcf_action_dump.
As such, the hw action stats update cb is called 3 times for every
tc flower filter dump.
Move the tc action hw stats update from tcf_action_copy_stats to
tcf_dump_walker to update the hw action stats when tc action is dumped.
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
We will report extack message if there is an error via netlink_ack(). But
if the rule is not to be exclusively executed by the hardware, extack is not
passed along and offloading failures don't get logged.
In commit 81c7288b170a ("sched: cls: enable verbose logging") Marcelo
made cls could log verbose info for offloading failures, which helps
improving Open vSwitch debuggability when using flower offloading.
It would also be helpful if userspace monitor tools, like "tc monitor",
could log this kind of message, as it doesn't require vswitchd log level
adjusment. Let's add a new tc attributes to report the extack message so
the monitor program could receive the failures. e.g.
# tc monitor
added chain dev enp3s0f1np1 parent ffff: chain 0
added filter dev enp3s0f1np1 ingress protocol all pref 49152 flower chain 0 handle 0x1
ct_state +trk+new
not_in_hw
action order 1: gact action drop
random type none pass val 0
index 1 ref 1 bind 1
Warning: mlx5_core: matching on ct_state +new isn't supported.
In this patch I only report the extack message on add/del operations.
It doesn't look like we need to report the extack message on get/dump
operations.
Note this message not only reporte to multicast groups, it could also
be reported unicast, which may affect the current usersapce tool's behaivor.
Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20230113034353.2766735-1-liuhangbin@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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>
Being able to get tc_action_net by using net_id stored in tc_action_ops
and execute the generic walk/search function, add __tcf_generic_walker()
and __tcf_idr_search() helpers.
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>
If during an action flush operation one of the actions is still being
referenced, the flush operation is aborted and the kernel returns to
user space with an error. However, if the kernel was able to flush, for
example, 3 actions and failed on the fourth, the kernel will not notify
user space that it deleted 3 actions before failing.
This patch fixes that behaviour by notifying user space of how many
actions were deleted before flush failed and by setting extack with a
message describing what happened.
Fixes: 55334a5db5cd ("net_sched: act: refuse to remove bound action outside")
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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>
Add extack message to return exact message to user when adding invalid
filter with conflict flags for TC action.
In previous implement we just return EINVAL which is confusing for user.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Link: https://lore.kernel.org/r/1646191769-17761-1-git-send-email-baowen.zheng@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Fix following coccicheck warning:
./net/sched/act_api.c:277:7-49: WARNING avoid newline at end of message
in NL_SET_ERR_MSG_MOD
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add process to validate flags of filter and actions when adding
a tc filter.
We need to prevent adding filter with flags conflicts with its actions.
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>
Add reoffload process to update hw_count when driver
is inserted or removed.
We will delete the action if it is with skip_sw flag and
not offloaded to any hardware in reoffload process.
When reoffloading actions, we still offload the actions
that are added independent of filters.
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>
Save full action flags and return user flags when return flags to
user space.
Save full action flags to distinguish if the action is created
independent from classifier.
We made this change mainly for further patch to reoffload tc actions.
Signed-off-by: Baowen Zheng <baowen.zheng@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>
When collecting stats for actions update them using both
hardware and software counters.
Stats update process should not run in context of preempt_disable.
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>
We add skip_hw and skip_sw for user to control if offload the action
to hardware.
We also add in_hw_count for user to indicate if the action is offloaded
to any hardware.
Signed-off-by: Baowen Zheng <baowen.zheng@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>
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>
The Qdisc::running sequence counter has two uses:
1. Reliably reading qdisc's tc statistics while the qdisc is running
(a seqcount read/retry loop at gnet_stats_add_basic()).
2. As a flag, indicating whether the qdisc in question is running
(without any retry loops).
For the first usage, the Qdisc::running sequence counter write section,
qdisc_run_begin() => qdisc_run_end(), covers a much wider area than what
is actually needed: the raw qdisc's bstats update. A u64_stats sync
point was thus introduced (in previous commits) inside the bstats
structure itself. A local u64_stats write section is then started and
stopped for the bstats updates.
Use that u64_stats sync point mechanism for the bstats read/retry loop
at gnet_stats_add_basic().
For the second qdisc->running usage, a __QDISC_STATE_RUNNING bit flag,
accessed with atomic bitops, is sufficient. Using a bit flag instead of
a sequence counter at qdisc_run_begin/end() and qdisc_is_running() leads
to the SMP barriers implicitly added through raw_read_seqcount() and
write_seqcount_begin/end() getting removed. All call sites have been
surveyed though, and no required ordering was identified.
Now that the qdisc->running sequence counter is no longer used, remove
it.
Note, using u64_stats implies no sequence counter protection for 64-bit
architectures. This can lead to the qdisc tc statistics "packets" vs.
"bytes" values getting out of sync on rare occasions. The individual
values will still be valid.
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>
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>
The not-per-CPU variant of qdisc tc (traffic control) statistics,
Qdisc::gnet_stats_basic_packed bstats, is protected with Qdisc::running
sequence counter.
This sequence counter is used for reliably protecting bstats reads from
parallel writes. Meanwhile, the seqcount's write section covers a much
wider area than bstats update: qdisc_run_begin() => qdisc_run_end().
That read/write section asymmetry can lead to needless retries of the
read section. To prepare for removing the Qdisc::running sequence
counter altogether, introduce a u64_stats sync point inside bstats
instead.
Modify _bstats_update() to start/end the bstats u64_stats write
section.
For bisectability, and finer commits granularity, the bstats read
section is still protected with a Qdisc::running read/retry loop and
qdisc_run_begin/end() still starts/ends that seqcount write section.
Once all call sites are modified to use _bstats_update(), the
Qdisc::running seqcount will be removed and bstats read/retry loop will
be modified to utilize the internal u64_stats sync point.
Note, using u64_stats implies no sequence counter protection for 64-bit
architectures. This can lead to the statistics "packets" vs. "bytes"
values getting out of sync on rare occasions. The individual values will
still be valid.
[bigeasy: Minor commit message edits, init all gnet_stats_basic_packed.]
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>
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>
It has been deal with the 'if (err' statement in rtnetlink_send()
and rtnl_unicast(). so remove unnecessary if statement.
v2: use the raw name rtnetlink_send().
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
When nla_put_u32() fails, 'ret' could be 0, it should
return error code in tcf_del_walker().
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With recent changes that separated action module load from action
initialization tcf_action_init() function error handling code was modified
to manually release the loaded modules if loading/initialization of any
further action in same batch failed. For the case when all modules
successfully loaded and some of the actions were initialized before one of
them failed in init handler. In this case for all previous actions the
module will be released twice by the error handler: First time by the loop
that manually calls module_put() for all ops, and second time by the action
destroy code that puts the module after destroying the action.
Reproduction:
$ sudo tc actions add action simple sdata \"2\" index 2
$ sudo tc actions add action simple sdata \"1\" index 1 \
action simple sdata \"2\" index 2
RTNETLINK answers: File exists
We have an error talking to the kernel
$ sudo tc actions ls action simple
total acts 1
action order 0: Simple <"2">
index 2 ref 1 bind 0
$ sudo tc actions flush action simple
$ sudo tc actions ls action simple
$ sudo tc actions add action simple sdata \"2\" index 2
Error: Failed to load TC action module.
We have an error talking to the kernel
$ lsmod | grep simple
act_simple 20480 -1
Fix the issue by modifying module reference counting handling in action
initialization code:
- Get module reference in tcf_idr_create() and put it in tcf_idr_release()
instead of taking over the reference held by the caller.
- Modify users of tcf_action_init_1() to always release the module
reference which they obtain before calling init function instead of
assuming that created action takes over the reference.
- Finally, modify tcf_action_init_1() to not release the module reference
when overwriting existing action as this is no longer necessary since both
upper and lower layers obtain and manage their own module references
independently.
Fixes: d349f9976868 ("net_sched: fix RTNL deadlock again caused by request_module()")
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Action init code increments reference counter when it changes an action.
This is the desired behavior for cls API which needs to obtain action
reference for every classifier that points to action. However, act API just
needs to change the action and releases the reference before returning.
This sequence breaks when the requested action doesn't exist, which causes
act API init code to create new action with specified index, but action is
still released before returning and is deleted (unless it was referenced
concurrently by cls API).
Reproduction:
$ sudo tc actions ls action gact
$ sudo tc actions change action gact drop index 1
$ sudo tc actions ls action gact
Extend tcf_action_init() to accept 'init_res' array and initialize it with
action->ops->init() result. In tcf_action_add() remove pointers to created
actions from actions array before passing it to tcf_action_put_many().
Fixes: cae422f379f3 ("net: sched: use reference counting action init")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 6855e8213e06efcaf7c02a15e12b1ae64b9a7149.
Following commit in series fixes the issue without introducing regression
in error rollback of tcf_action_destroy().
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, action creation using ACT API in replace mode is buggy.
When invoking for non-existent action index 42,
tc action replace action bpf obj foo.o sec <xyz> index 42
kernel creates the action, fills up the netlink response, and then just
deletes the action after notifying userspace.
tc action show action bpf
doesn't list the action.
This happens due to the following sequence when ovr = 1 (replace mode)
is enabled:
tcf_idr_check_alloc is used to atomically check and either obtain
reference for existing action at index, or reserve the index slot using
a dummy entry (ERR_PTR(-EBUSY)).
This is necessary as pointers to these actions will be held after
dropping the idrinfo lock, so bumping the reference count is necessary
as we need to insert the actions, and notify userspace by dumping their
attributes. Finally, we drop the reference we took using the
tcf_action_put_many call in tcf_action_add. However, for the case where
a new action is created due to free index, its refcount remains one.
This when paired with the put_many call leads to the kernel setting up
the action, notifying userspace of its creation, and then tearing it
down. For existing actions, the refcount is still held so they remain
unaffected.
Fortunately due to rtnl_lock serialization requirement, such an action
with refcount == 1 will not be concurrently deleted by anything else, at
best CLS API can move its refcount up and down by binding to it after it
has been published from tcf_idr_insert_many. Since refcount is atleast
one until put_many call, CLS API cannot delete it. Also __tcf_action_put
release path already ensures deterministic outcome (either new action
will be created or existing action will be reused in case CLS API tries
to bind to action concurrently) due to idr lock serialization.
We fix this by making refcount of newly created actions as 2 in ACT API
replace mode. A relaxed store will suffice as visibility is ensured only
after the tcf_idr_insert_many call.
Note that in case of creation or overwriting using CLS API only (i.e.
bind = 1), overwriting existing action object is not allowed, and any
such request is silently ignored (without error).
The refcount bump that occurs in tcf_idr_check_alloc call there for
existing action will pair with tcf_exts_destroy call made from the
owner module for the same action. In case of action creation, there
is no existing action, so no tcf_exts_destroy callback happens.
This means no code changes for CLS API.
Fixes: cae422f379f3 ("net: sched: use reference counting action init")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcf_action_init_1() loads tc action modules automatically with
request_module() after parsing the tc action names, and it drops RTNL
lock and re-holds it before and after request_module(). This causes a
lot of troubles, as discovered by syzbot, because we can be in the
middle of batch initializations when we create an array of tc actions.
One of the problem is deadlock:
CPU 0 CPU 1
rtnl_lock();
for (...) {
tcf_action_init_1();
-> rtnl_unlock();
-> request_module();
rtnl_lock();
for (...) {
tcf_action_init_1();
-> tcf_idr_check_alloc();
// Insert one action into idr,
// but it is not committed until
// tcf_idr_insert_many(), then drop
// the RTNL lock in the _next_
// iteration
-> rtnl_unlock();
-> rtnl_lock();
-> a_o->init();
-> tcf_idr_check_alloc();
// Now waiting for the same index
// to be committed
-> request_module();
-> rtnl_lock()
// Now waiting for RTNL lock
}
rtnl_unlock();
}
rtnl_unlock();
This is not easy to solve, we can move the request_module() before
this loop and pre-load all the modules we need for this netlink
message and then do the rest initializations. So the loop breaks down
to two now:
for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) {
struct tc_action_ops *a_o;
a_o = tc_action_load_ops(name, tb[i]...);
ops[i - 1] = a_o;
}
for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) {
act = tcf_action_init_1(ops[i - 1]...);
}
Although this looks serious, it only has been reported by syzbot, so it
seems hard to trigger this by humans. And given the size of this patch,
I'd suggest to make it to net-next and not to backport to stable.
This patch has been tested by syzbot and tested with tdc.py by me.
Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together")
Reported-and-tested-by: syzbot+82752bc5331601cf4899@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+b3b63b6bff456bd95294@syzkaller.appspotmail.com
Reported-by: syzbot+ba67b12b1ca729912834@syzkaller.appspotmail.com
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20210117005657.14810-1-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently kernel tc subsystem can do conntrack in cat_ct. But when several
fragment packets go through the act_ct, function tcf_ct_handle_fragments
will defrag the packets to a big one. But the last action will redirect
mirred to a device which maybe lead the reassembly big packet over the mtu
of target device.
This patch add support for a xmit hook to mirred, that gets executed before
xmiting the packet. Then, when act_ct gets loaded, it configs that hook.
The frag xmit hook maybe reused by other modules.
Signed-off-by: wenxu <wenxu@ucloud.cn>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently both filter and action flags use same "TCA_" prefix which makes
them hard to distinguish to code and confusing for users. Create aliases
for existing action flags constants with "TCA_ACT_" prefix.
Signed-off-by: Vlad Buslov <vlad@buslov.dev>
Link: https://lore.kernel.org/r/20201124164054.893168-1-vlad@buslov.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
