Commit Graph

3287 Commits

Author SHA1 Message Date
Maxim Mikityanskiy
648a991cf3 sch_htb: Add extack messages for EOPNOTSUPP errors
In order to make the "Operation not supported" message clearer to the
user, add extack messages explaining why exactly adding offloaded HTB
could be not supported in each case.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-28 14:34:03 +01:00
Paolo Abeni
292e6077b0 net: introduce sk_forward_alloc_get()
A later patch will change the MPTCP memory accounting schema
in such a way that MPTCP sockets will encode the total amount of
forward allocated memory in two separate fields (one for tx and
one for rx).

MPTCP sockets will use their own helper to provide the accurate
amount of fwd allocated memory.

To allow the above, this patch adds a new, optional, sk method to
fetch the fwd memory, wrap the call in a new helper and use it
where it is appropriate.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-27 18:20:29 -07:00
Seth Forshee
85c0c3eb9a net: sch: simplify condtion for selecting mini_Qdisc_pair buffer
The only valid values for a miniq pointer are NULL or a pointer to
miniq1 or miniq2, so testing for miniq_old != &miniq1 is functionally
equivalent to testing that it is NULL or equal to &miniq2.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Seth Forshee <sforshee@digitalocean.com>
Link: https://lore.kernel.org/r/20211026183721.137930-1-seth@forshee.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-27 17:09:26 -07:00
Seth Forshee
267463823a net: sch: eliminate unnecessary RCU waits in mini_qdisc_pair_swap()
Currently rcu_barrier() is used to ensure that no readers of the
inactive mini_Qdisc buffer remain before it is reused. This waits for
any pending RCU callbacks to complete, when all that is actually
required is to wait for one RCU grace period to elapse after the buffer
was made inactive. This means that using rcu_barrier() may result in
unnecessary waits.

To improve this, store the current RCU state when a buffer is made
inactive and use poll_state_synchronize_rcu() to check whether a full
grace period has elapsed before reusing it. If a full grace period has
not elapsed, wait for a grace period to elapse, and in the non-RT case
use synchronize_rcu_expedited() to hasten it.

Since this approach eliminates the RCU callback it is no longer
necessary to synchronize_rcu() in the tp_head==NULL case. However, the
RCU state should still be saved for the previously active buffer.

Before this change I would typically see mini_qdisc_pair_swap() take
tens of milliseconds to complete. After this change it typcially
finishes in less than 1 ms, and often it takes just a few microseconds.

Thanks to Paul for walking me through the options for improving this.

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Seth Forshee <sforshee@digitalocean.com>
Link: https://lore.kernel.org/r/20211026130700.121189-1-seth@forshee.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-27 17:09:26 -07:00
Arnd Bergmann
f25c0515c5 net: sched: gred: dynamically allocate tc_gred_qopt_offload
The tc_gred_qopt_offload structure has grown too big to be on the
stack for 32-bit architectures after recent changes.

net/sched/sch_gred.c:903:13: error: stack frame size (1180) exceeds limit (1024) in 'gred_destroy' [-Werror,-Wframe-larger-than]
net/sched/sch_gred.c:310:13: error: stack frame size (1212) exceeds limit (1024) in 'gred_offload' [-Werror,-Wframe-larger-than]

Use dynamic allocation per qdisc to avoid this.

Fixes: 50dc9a8572 ("net: sched: Merge Qdisc::bstats and Qdisc::cpu_bstats data types")
Fixes: 67c9e6270f ("net: sched: Protect Qdisc::bstats with u64_stats")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20211026100711.nalhttf6mbe6sudx@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-27 12:06:52 -07:00
David S. Miller
bdfa75ad70 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Lots of simnple overlapping additions.

With a build fix from Stephen Rothwell.

Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-22 11:41:16 +01:00
Toke Høiland-Jørgensen
dfcb63ce1d fq_codel: generalise ce_threshold marking for subset of traffic
Commit e72aeb9ee0 ("fq_codel: implement L4S style ce_threshold_ect1
marking") expanded the ce_threshold feature of FQ-CoDel so it can
be applied to a subset of the traffic, using the ECT(1) bit of the ECN
field as the classifier. However, hard-coding ECT(1) as the only
classifier for this feature seems limiting, so let's expand it to be more
general.

To this end, change the parameter from a ce_threshold_ect1 boolean, to a
one-byte selector/mask pair (ce_threshold_{selector,mask}) which is applied
to the whole diffserv/ECN field in the IP header. This makes it possible to
classify packets by any value in either the ECN field or the diffserv
field. In particular, setting a selector of INET_ECN_ECT_1 and a mask of
INET_ECN_MASK corresponds to the functionality before this patch, and a
mask of ~INET_ECN_MASK allows using the selector as a straight-forward
match against a diffserv code point:

 # apply ce_threshold to ECT(1) traffic
 tc qdisc replace dev eth0 root fq_codel ce_threshold 1ms ce_threshold_selector 0x1/0x3

 # apply ce_threshold to ECN-capable traffic marked as diffserv AF22
 tc qdisc replace dev eth0 root fq_codel ce_threshold 1ms ce_threshold_selector 0x50/0xfc

Regardless of the selector chosen, the normal rules for ECN-marking of
packets still apply, i.e., the flow must still declare itself ECN-capable
by setting one of the bits in the ECN field to get marked at all.

v2:
- Add tc usage examples to patch description

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20211019174709.69081-1-toke@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-20 15:24:36 -07:00
Petr Machata
6b3efbfa4e net: sch_tbf: Add a graft command
As another qdisc is linked to the TBF, the latter should issue an event to
give drivers a chance to react to the grafting. In other qdiscs, this event
is called GRAFT, so follow suit with TBF as well.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-19 12:24:51 +01:00
Paul Blakey
2dc4e9e88c net/sched: act_ct: Fix byte count on fragmented packets
First fragmented packets (frag offset = 0) byte len is zeroed
when stolen by ip_defrag(). And since act_ct update the stats
only afterwards (at end of execute), bytes aren't correctly
accounted for such packets.

To fix this, move stats update to start of action execute.

Fixes: b57dc7c13e ("net/sched: Introduce action ct")
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-18 13:31:58 +01:00
Ahmed S. Darwish
29cbcd8582 net: sched: Remove Qdisc::running sequence counter
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>
2021-10-18 12:54:41 +01:00
Ahmed S. Darwish
50dc9a8572 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>
2021-10-18 12:54:41 +01:00
Ahmed S. Darwish
f56940daa5 net: sched: Use _bstats_update/set() instead of raw writes
The Qdisc::running sequence counter, used to protect Qdisc::bstats reads
from parallel writes, is in the process of being removed. Qdisc::bstats
read/writes will synchronize using an internal u64_stats sync point
instead.

Modify all bstats writes to use _bstats_update(). This ensures that
the internal u64_stats sync point is always acquired and released as
appropriate.

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>
2021-10-18 12:54:41 +01:00
Ahmed S. Darwish
67c9e6270f net: sched: Protect Qdisc::bstats with u64_stats
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>
2021-10-18 12:54:41 +01:00
Sebastian Andrzej Siewior
7361df4606 mq, mqprio: Use gnet_stats_add_queue().
gnet_stats_add_basic() and gnet_stats_add_queue() add up the statistics
so they can be used directly for both the per-CPU and global case.

gnet_stats_add_queue() copies either Qdisc's per-CPU
gnet_stats_queue::qlen or the global member. The global
gnet_stats_queue::qlen isn't touched in the per-CPU case so there is no
need to consider it in the global-case.

In the per-CPU case, the sum of global gnet_stats_queue::qlen and
the per-CPU gnet_stats_queue::qlen was assigned to sch->q.qlen and
sch->qstats.qlen. Now both fields are copied individually.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-18 12:54:41 +01:00
Sebastian Andrzej Siewior
fbf307c89e gen_stats: Add instead Set the value in __gnet_stats_copy_basic().
__gnet_stats_copy_basic() always assigns the value to the bstats
argument overwriting the previous value. The later added per-CPU version
always accumulated the values in the returning gnet_stats_basic_packed
argument.

Based on review there are five users of that function as of today:
- est_fetch_counters(), ___gnet_stats_copy_basic()
  memsets() bstats to zero, single invocation.

- mq_dump(), mqprio_dump(), mqprio_dump_class_stats()
  memsets() bstats to zero, multiple invocation but does not use the
  function due to !qdisc_is_percpu_stats().

Add the values in __gnet_stats_copy_basic() instead overwriting. Rename
the function to gnet_stats_add_basic() to make it more obvious.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-18 12:54:40 +01:00
Eric Dumazet
e72aeb9ee0 fq_codel: implement L4S style ce_threshold_ect1 marking
Add TCA_FQ_CODEL_CE_THRESHOLD_ECT1 boolean option to select Low Latency,
Low Loss, Scalable Throughput (L4S) style marking, along with ce_threshold.

If enabled, only packets with ECT(1) can be transformed to CE
if their sojourn time is above the ce_threshold.

Note that this new option does not change rules for codel law.
In particular, if TCA_FQ_CODEL_ECN is left enabled (this is
the default when fq_codel qdisc is created), ECT(0) packets can
still get CE if codel law (as governed by limit/target) decides so.

Section 4.3.b of current draft [1] states:

b.  A scheduler with per-flow queues such as FQ-CoDel or FQ-PIE can
    be used for L4S.  For instance within each queue of an FQ-CoDel
    system, as well as a CoDel AQM, there is typically also ECN
    marking at an immediate (unsmoothed) shallow threshold to support
    use in data centres (see Sec.5.2.7 of [RFC8290]).  This can be
    modified so that the shallow threshold is solely applied to
    ECT(1) packets.  Then if there is a flow of non-ECN or ECT(0)
    packets in the per-flow-queue, the Classic AQM (e.g.  CoDel) is
    applied; while if there is a flow of ECT(1) packets in the queue,
    the shallower (typically sub-millisecond) threshold is applied.

Tested:

tc qd replace dev eth1 root fq_codel ce_threshold_ect1 50usec

netperf ... -t TCP_STREAM -- K dctcp

tc -s -d qd sh dev eth1
qdisc fq_codel 8022: root refcnt 32 limit 10240p flows 1024 quantum 9212 target 5ms ce_threshold_ect1 49us interval 100ms memory_limit 32Mb ecn drop_batch 64
 Sent 14388596616 bytes 9543449 pkt (dropped 0, overlimits 0 requeues 152013)
 backlog 0b 0p requeues 152013
  maxpacket 68130 drop_overlimit 0 new_flow_count 95678 ecn_mark 0 ce_mark 7639
  new_flows_len 0 old_flows_len 0

[1] L4S current draft:
https://datatracker.ietf.org/doc/html/draft-ietf-tsvwg-l4s-arch

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Ingemar Johansson S <ingemar.s.johansson@ericsson.com>
Cc: Tom Henderson <tomh@tomh.org>
Cc: Bob Briscoe <in@bobbriscoe.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-15 11:33:08 +01:00
Jakub Kicinski
e15f5972b8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
tools/testing/selftests/net/ioam6.sh
  7b1700e009 ("selftests: net: modify IOAM tests for undef bits")
  bf77b1400a ("selftests: net: Test for the IOAM encapsulation with IPv6")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-14 16:50:14 -07:00
Sebastian Andrzej Siewior
1413269086 mqprio: Correct stats in mqprio_dump_class_stats().
Introduction of lockless subqueues broke the class statistics.
Before the change stats were accumulated in `bstats' and `qstats'
on the stack which was then copied to struct gnet_dump.

After the change the `bstats' and `qstats' are initialized to 0
and never updated, yet still fed to gnet_dump. The code updates
the global qdisc->cpu_bstats and qdisc->cpu_qstats instead,
clobbering them. Most likely a copy-paste error from the code in
mqprio_dump().

__gnet_stats_copy_basic() and __gnet_stats_copy_queue() accumulate
the values for per-CPU case but for global stats they overwrite
the value, so only stats from the last loop iteration / tc end up
in sch->[bq]stats.

Use the on-stack [bq]stats variables again and add the stats manually
in the global case.

Fixes: ce679e8df7 ("net: sched: add support for TCQ_F_NOLOCK subqueues to sch_mqprio")
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
https://lore.kernel.org/all/20211007175000.2334713-2-bigeasy@linutronix.de/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-08 16:27:22 -07:00
Davide Caratti
454d3e1ae0 net/sched: sch_ets: properly init all active DRR list handles
leaf classes of ETS qdiscs are served in strict priority or deficit round
robin (DRR), depending on the value of 'nstrict'. Since this value can be
changed while traffic is running, we need to be sure that the active list
of DRR classes can be updated at any time, so:

1) call INIT_LIST_HEAD(&alist) on all leaf classes in .init(), before the
   first packet hits any of them.
2) ensure that 'alist' is not overwritten with zeros when a leaf class is
   no more strict priority nor DRR (i.e. array elements beyond 'nbands').

Link: https://lore.kernel.org/netdev/YS%2FoZ+f0Nr8eQkzH@dcaratti.users.ipa.redhat.com
Suggested-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-08 15:20:05 +01:00
Jakub Kicinski
9fe1155233 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-07 15:24:06 -07:00
Eric Dumazet
a56d447f19 net/sched: sch_taprio: properly cancel timer from taprio_destroy()
There is a comment in qdisc_create() about us not calling ops->reset()
in some cases.

err_out4:
	/*
	 * Any broken qdiscs that would require a ops->reset() here?
	 * The qdisc was never in action so it shouldn't be necessary.
	 */

As taprio sets a timer before actually receiving a packet, we need
to cancel it from ops->destroy, just in case ops->reset has not
been called.

syzbot reported:

ODEBUG: free active (active state 0) object type: hrtimer hint: advance_sched+0x0/0x9a0 arch/x86/include/asm/atomic64_64.h:22
WARNING: CPU: 0 PID: 8441 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Modules linked in:
CPU: 0 PID: 8441 Comm: syz-executor813 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 af 00 00 00 48 8b 14 dd e0 d3 e3 89 4c 89 ee 48 c7 c7 e0 c7 e3 89 e8 5b 86 11 05 <0f> 0b 83 05 85 03 92 09 01 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e c3
RSP: 0018:ffffc9000130f330 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: ffff88802baeb880 RSI: ffffffff815d87b5 RDI: fffff52000261e58
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815d25ee R11: 0000000000000000 R12: ffffffff898dd020
R13: ffffffff89e3ce20 R14: ffffffff81653630 R15: dffffc0000000000
FS:  0000000000f0d300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffb64b3e000 CR3: 0000000036557000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __debug_check_no_obj_freed lib/debugobjects.c:987 [inline]
 debug_check_no_obj_freed+0x301/0x420 lib/debugobjects.c:1018
 slab_free_hook mm/slub.c:1603 [inline]
 slab_free_freelist_hook+0x171/0x240 mm/slub.c:1653
 slab_free mm/slub.c:3213 [inline]
 kfree+0xe4/0x540 mm/slub.c:4267
 qdisc_create+0xbcf/0x1320 net/sched/sch_api.c:1299
 tc_modify_qdisc+0x4c8/0x1a60 net/sched/sch_api.c:1663
 rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5571
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2403
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2457
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80

Fixes: 44d4775ca5 ("net/sched: sch_taprio: reset child qdiscs before freeing them")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Davide Caratti <dcaratti@redhat.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-05 12:45:27 +01:00
Eric Dumazet
560ee196fe net_sched: fix NULL deref in fifo_set_limit()
syzbot reported another NULL deref in fifo_set_limit() [1]

I could repro the issue with :

unshare -n
tc qd add dev lo root handle 1:0 tbf limit 200000 burst 70000 rate 100Mbit
tc qd replace dev lo parent 1:0 pfifo_fast
tc qd change dev lo root handle 1:0 tbf limit 300000 burst 70000 rate 100Mbit

pfifo_fast does not have a change() operation.
Make fifo_set_limit() more robust about this.

[1]
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 1cf99067 P4D 1cf99067 PUD 7ca49067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 14443 Comm: syz-executor959 Not tainted 5.15.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc9000e2f7310 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffff8d6ecc00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff888024c27910 RDI: ffff888071e34000
RBP: ffff888071e34000 R08: 0000000000000001 R09: ffffffff8fcfb947
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888024c27910
R13: ffff888071e34018 R14: 0000000000000000 R15: ffff88801ef74800
FS:  00007f321d897700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000722c3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 fifo_set_limit net/sched/sch_fifo.c:242 [inline]
 fifo_set_limit+0x198/0x210 net/sched/sch_fifo.c:227
 tbf_change+0x6ec/0x16d0 net/sched/sch_tbf.c:418
 qdisc_change net/sched/sch_api.c:1332 [inline]
 tc_modify_qdisc+0xd9a/0x1a60 net/sched/sch_api.c:1634
 rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5572
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: fb0305ce1b ("net-sched: consolidate default fifo qdisc setup")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20210930212239.3430364-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-01 14:59:10 -07:00
Gustavo A. R. Silva
129291980f net: sched: Use struct_size() helper in kvmalloc()
Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows
that, in the worst scenario, could lead to heap overflows.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20210929201718.GA342296@embeddedor
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-09-30 17:27:03 -07:00
Jakub Kicinski
dd9a887b35 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/phy/bcm7xxx.c
  d88fd1b546 ("net: phy: bcm7xxx: Fixed indirect MMD operations")
  f68d08c437 ("net: phy: bcm7xxx: Add EPHY entry for 72165")

net/sched/sch_api.c
  b193e15ac6 ("net: prevent user from passing illegal stab size")
  69508d4333 ("net_sched: Use struct_size() and flex_array_size() helpers")

Both cases trivial - adjacent code additions.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-09-30 14:49:21 -07:00
Vlad Buslov
d5ef190693 net: sched: flower: protect fl_walk() with rcu
Patch that refactored fl_walk() to use idr_for_each_entry_continue_ul()
also removed rcu protection of individual filters which causes following
use-after-free when filter is deleted concurrently. Fix fl_walk() to obtain
rcu read lock while iterating and taking the filter reference and temporary
release the lock while calling arg->fn() callback that can sleep.

KASAN trace:

[  352.773640] ==================================================================
[  352.775041] BUG: KASAN: use-after-free in fl_walk+0x159/0x240 [cls_flower]
[  352.776304] Read of size 4 at addr ffff8881c8251480 by task tc/2987

[  352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2
[  352.778980] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[  352.781022] Call Trace:
[  352.781573]  dump_stack_lvl+0x46/0x5a
[  352.782332]  print_address_description.constprop.0+0x1f/0x140
[  352.783400]  ? fl_walk+0x159/0x240 [cls_flower]
[  352.784292]  ? fl_walk+0x159/0x240 [cls_flower]
[  352.785138]  kasan_report.cold+0x83/0xdf
[  352.785851]  ? fl_walk+0x159/0x240 [cls_flower]
[  352.786587]  kasan_check_range+0x145/0x1a0
[  352.787337]  fl_walk+0x159/0x240 [cls_flower]
[  352.788163]  ? fl_put+0x10/0x10 [cls_flower]
[  352.789007]  ? __mutex_unlock_slowpath.constprop.0+0x220/0x220
[  352.790102]  tcf_chain_dump+0x231/0x450
[  352.790878]  ? tcf_chain_tp_delete_empty+0x170/0x170
[  352.791833]  ? __might_sleep+0x2e/0xc0
[  352.792594]  ? tfilter_notify+0x170/0x170
[  352.793400]  ? __mutex_unlock_slowpath.constprop.0+0x220/0x220
[  352.794477]  tc_dump_tfilter+0x385/0x4b0
[  352.795262]  ? tc_new_tfilter+0x1180/0x1180
[  352.796103]  ? __mod_node_page_state+0x1f/0xc0
[  352.796974]  ? __build_skb_around+0x10e/0x130
[  352.797826]  netlink_dump+0x2c0/0x560
[  352.798563]  ? netlink_getsockopt+0x430/0x430
[  352.799433]  ? __mutex_unlock_slowpath.constprop.0+0x220/0x220
[  352.800542]  __netlink_dump_start+0x356/0x440
[  352.801397]  rtnetlink_rcv_msg+0x3ff/0x550
[  352.802190]  ? tc_new_tfilter+0x1180/0x1180
[  352.802872]  ? rtnl_calcit.isra.0+0x1f0/0x1f0
[  352.803668]  ? tc_new_tfilter+0x1180/0x1180
[  352.804344]  ? _copy_from_iter_nocache+0x800/0x800
[  352.805202]  ? kasan_set_track+0x1c/0x30
[  352.805900]  netlink_rcv_skb+0xc6/0x1f0
[  352.806587]  ? rht_deferred_worker+0x6b0/0x6b0
[  352.807455]  ? rtnl_calcit.isra.0+0x1f0/0x1f0
[  352.808324]  ? netlink_ack+0x4d0/0x4d0
[  352.809086]  ? netlink_deliver_tap+0x62/0x3d0
[  352.809951]  netlink_unicast+0x353/0x480
[  352.810744]  ? netlink_attachskb+0x430/0x430
[  352.811586]  ? __alloc_skb+0xd7/0x200
[  352.812349]  netlink_sendmsg+0x396/0x680
[  352.813132]  ? netlink_unicast+0x480/0x480
[  352.813952]  ? __import_iovec+0x192/0x210
[  352.814759]  ? netlink_unicast+0x480/0x480
[  352.815580]  sock_sendmsg+0x6c/0x80
[  352.816299]  ____sys_sendmsg+0x3a5/0x3c0
[  352.817096]  ? kernel_sendmsg+0x30/0x30
[  352.817873]  ? __ia32_sys_recvmmsg+0x150/0x150
[  352.818753]  ___sys_sendmsg+0xd8/0x140
[  352.819518]  ? sendmsg_copy_msghdr+0x110/0x110
[  352.820402]  ? ___sys_recvmsg+0xf4/0x1a0
[  352.821110]  ? __copy_msghdr_from_user+0x260/0x260
[  352.821934]  ? _raw_spin_lock+0x81/0xd0
[  352.822680]  ? __handle_mm_fault+0xef3/0x1b20
[  352.823549]  ? rb_insert_color+0x2a/0x270
[  352.824373]  ? copy_page_range+0x16b0/0x16b0
[  352.825209]  ? perf_event_update_userpage+0x2d0/0x2d0
[  352.826190]  ? __fget_light+0xd9/0xf0
[  352.826941]  __sys_sendmsg+0xb3/0x130
[  352.827613]  ? __sys_sendmsg_sock+0x20/0x20
[  352.828377]  ? do_user_addr_fault+0x2c5/0x8a0
[  352.829184]  ? fpregs_assert_state_consistent+0x52/0x60
[  352.830001]  ? exit_to_user_mode_prepare+0x32/0x160
[  352.830845]  do_syscall_64+0x35/0x80
[  352.831445]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  352.832331] RIP: 0033:0x7f7bee973c17
[  352.833078] Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
[  352.836202] RSP: 002b:00007ffcbb368e28 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  352.837524] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7bee973c17
[  352.838715] RDX: 0000000000000000 RSI: 00007ffcbb368e50 RDI: 0000000000000003
[  352.839838] RBP: 00007ffcbb36d090 R08: 00000000cea96d79 R09: 00007f7beea34a40
[  352.841021] R10: 00000000004059bb R11: 0000000000000246 R12: 000000000046563f
[  352.842208] R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffcbb36d088

[  352.843784] Allocated by task 2960:
[  352.844451]  kasan_save_stack+0x1b/0x40
[  352.845173]  __kasan_kmalloc+0x7c/0x90
[  352.845873]  fl_change+0x282/0x22db [cls_flower]
[  352.846696]  tc_new_tfilter+0x6cf/0x1180
[  352.847493]  rtnetlink_rcv_msg+0x471/0x550
[  352.848323]  netlink_rcv_skb+0xc6/0x1f0
[  352.849097]  netlink_unicast+0x353/0x480
[  352.849886]  netlink_sendmsg+0x396/0x680
[  352.850678]  sock_sendmsg+0x6c/0x80
[  352.851398]  ____sys_sendmsg+0x3a5/0x3c0
[  352.852202]  ___sys_sendmsg+0xd8/0x140
[  352.852967]  __sys_sendmsg+0xb3/0x130
[  352.853718]  do_syscall_64+0x35/0x80
[  352.854457]  entry_SYSCALL_64_after_hwframe+0x44/0xae

[  352.855830] Freed by task 7:
[  352.856421]  kasan_save_stack+0x1b/0x40
[  352.857139]  kasan_set_track+0x1c/0x30
[  352.857854]  kasan_set_free_info+0x20/0x30
[  352.858609]  __kasan_slab_free+0xed/0x130
[  352.859348]  kfree+0xa7/0x3c0
[  352.859951]  process_one_work+0x44d/0x780
[  352.860685]  worker_thread+0x2e2/0x7e0
[  352.861390]  kthread+0x1f4/0x220
[  352.862022]  ret_from_fork+0x1f/0x30

[  352.862955] Last potentially related work creation:
[  352.863758]  kasan_save_stack+0x1b/0x40
[  352.864378]  kasan_record_aux_stack+0xab/0xc0
[  352.865028]  insert_work+0x30/0x160
[  352.865617]  __queue_work+0x351/0x670
[  352.866261]  rcu_work_rcufn+0x30/0x40
[  352.866917]  rcu_core+0x3b2/0xdb0
[  352.867561]  __do_softirq+0xf6/0x386

[  352.868708] Second to last potentially related work creation:
[  352.869779]  kasan_save_stack+0x1b/0x40
[  352.870560]  kasan_record_aux_stack+0xab/0xc0
[  352.871426]  call_rcu+0x5f/0x5c0
[  352.872108]  queue_rcu_work+0x44/0x50
[  352.872855]  __fl_put+0x17c/0x240 [cls_flower]
[  352.873733]  fl_delete+0xc7/0x100 [cls_flower]
[  352.874607]  tc_del_tfilter+0x510/0xb30
[  352.886085]  rtnetlink_rcv_msg+0x471/0x550
[  352.886875]  netlink_rcv_skb+0xc6/0x1f0
[  352.887636]  netlink_unicast+0x353/0x480
[  352.888285]  netlink_sendmsg+0x396/0x680
[  352.888942]  sock_sendmsg+0x6c/0x80
[  352.889583]  ____sys_sendmsg+0x3a5/0x3c0
[  352.890311]  ___sys_sendmsg+0xd8/0x140
[  352.891019]  __sys_sendmsg+0xb3/0x130
[  352.891716]  do_syscall_64+0x35/0x80
[  352.892395]  entry_SYSCALL_64_after_hwframe+0x44/0xae

[  352.893666] The buggy address belongs to the object at ffff8881c8251000
                which belongs to the cache kmalloc-2k of size 2048
[  352.895696] The buggy address is located 1152 bytes inside of
                2048-byte region [ffff8881c8251000, ffff8881c8251800)
[  352.897640] The buggy address belongs to the page:
[  352.898492] page:00000000213bac35 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c8250
[  352.900110] head:00000000213bac35 order:3 compound_mapcount:0 compound_pincount:0
[  352.901541] flags: 0x2ffff800010200(slab|head|node=0|zone=2|lastcpupid=0x1ffff)
[  352.902908] raw: 002ffff800010200 0000000000000000 dead000000000122 ffff888100042f00
[  352.904391] raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
[  352.905861] page dumped because: kasan: bad access detected

[  352.907323] Memory state around the buggy address:
[  352.908218]  ffff8881c8251380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  352.909471]  ffff8881c8251400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  352.910735] >ffff8881c8251480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  352.912012]                    ^
[  352.912642]  ffff8881c8251500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  352.913919]  ffff8881c8251580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  352.915185] ==================================================================

Fixes: d39d714969 ("idr: introduce idr_for_each_entry_continue_ul()")
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-30 13:20:31 +01:00
Gustavo A. R. Silva
69508d4333 net_sched: Use struct_size() and flex_array_size() helpers
Make use of the struct_size() and flex_array_size() helpers instead of
an open-coded version, in order to avoid any potential type mistakes
or integer overflows that, in the worse scenario, could lead to heap
overflows.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20210928193107.GA262595@embeddedor
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-09-29 18:56:53 -07:00
王贇
b193e15ac6 net: prevent user from passing illegal stab size
We observed below report when playing with netlink sock:

  UBSAN: shift-out-of-bounds in net/sched/sch_api.c:580:10
  shift exponent 249 is too large for 32-bit type
  CPU: 0 PID: 685 Comm: a.out Not tainted
  Call Trace:
   dump_stack_lvl+0x8d/0xcf
   ubsan_epilogue+0xa/0x4e
   __ubsan_handle_shift_out_of_bounds+0x161/0x182
   __qdisc_calculate_pkt_len+0xf0/0x190
   __dev_queue_xmit+0x2ed/0x15b0

it seems like kernel won't check the stab log value passing from
user, and will use the insane value later to calculate pkt_len.

This patch just add a check on the size/cell_log to avoid insane
calculation.

Reported-by: Abaci <abaci@linux.alibaba.com>
Signed-off-by: Michael Wang <yun.wang@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-26 11:09:07 +01:00
Jakub Kicinski
f7116fb460 net: sched: move and reuse mq_change_real_num_tx()
The code for handling active queue changes is identical
between mq and mqprio, reuse it.

Suggested-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-19 13:26:01 +01:00
Jakub Kicinski
1e080f1775 net: sched: update default qdisc visibility after Tx queue cnt changes
mq / mqprio make the default child qdiscs visible. They only do
so for the qdiscs which are within real_num_tx_queues when the
device is registered. Depending on order of calls in the driver,
or if user space changes config via ethtool -L the number of
qdiscs visible under tc qdisc show will differ from the number
of queues. This is confusing to users and potentially to system
configuration scripts which try to make sure qdiscs have the
right parameters.

Add a new Qdisc_ops callback and make relevant qdiscs TTRT.

Note that this uncovers the "shortcut" created by
commit 1f27cde313 ("net: sched: use pfifo_fast for non real queues")
The default child qdiscs beyond initial real_num_tx are always
pfifo_fast, no matter what the sysfs setting is. Fixing this
gets a little tricky because we'd need to keep a reference
on whatever the default qdisc was at the time of creation.
In practice this is likely an non-issue the qdiscs likely have
to be configured to non-default settings, so whatever user space
is doing such configuration can replace the pfifos... now that
it will see them.

Reported-by: Matthew Massey <matthewmassey@fb.com>
Reviewed-by: Dave Taht <dave.taht@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-15 15:46:02 +01:00
Eric Dumazet
c7c5e6ff53 fq_codel: reject silly quantum parameters
syzbot found that forcing a big quantum attribute would crash hosts fast,
essentially using this:

tc qd replace dev eth0 root fq_codel quantum 4294967295

This is because fq_codel_dequeue() would have to loop
~2^31 times in :

	if (flow->deficit <= 0) {
		flow->deficit += q->quantum;
		list_move_tail(&flow->flowchain, &q->old_flows);
		goto begin;
	}

SFQ max quantum is 2^19 (half a megabyte)
Lets adopt a max quantum of one megabyte for FQ_CODEL.

Fixes: 4b549a2ef4 ("fq_codel: Fair Queue Codel AQM")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-04 10:49:46 +01:00
Xiyu Yang
c660701258 net: sched: Fix qdisc_rate_table refcount leak when get tcf_block failed
The reference counting issue happens in one exception handling path of
cbq_change_class(). When failing to get tcf_block, the function forgets
to decrease the refcount of "rtab" increased by qdisc_put_rtab(),
causing a refcount leak.

Fix this issue by jumping to "failure" label when get tcf_block failed.

Fixes: 6529eaba33 ("net: sched: introduce tcf block infractructure")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Link: https://lore.kernel.org/r/1630252681-71588-1-git-send-email-xiyuyang19@fudan.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-30 20:29:03 -07:00
Jakub Kicinski
19a31d7921 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
bpf-next 2021-08-31

We've added 116 non-merge commits during the last 17 day(s) which contain
a total of 126 files changed, 6813 insertions(+), 4027 deletions(-).

The main changes are:

1) Add opaque bpf_cookie to perf link which the program can read out again,
   to be used in libbpf-based USDT library, from Andrii Nakryiko.

2) Add bpf_task_pt_regs() helper to access userspace pt_regs, from Daniel Xu.

3) Add support for UNIX stream type sockets for BPF sockmap, from Jiang Wang.

4) Allow BPF TCP congestion control progs to call bpf_setsockopt() e.g. to switch
   to another congestion control algorithm during init, from Martin KaFai Lau.

5) Extend BPF iterator support for UNIX domain sockets, from Kuniyuki Iwashima.

6) Allow bpf_{set,get}sockopt() calls from setsockopt progs, from Prankur Gupta.

7) Add bpf_get_netns_cookie() helper for BPF_PROG_TYPE_{SOCK_OPS,CGROUP_SOCKOPT}
   progs, from Xu Liu and Stanislav Fomichev.

8) Support for __weak typed ksyms in libbpf, from Hao Luo.

9) Shrink struct cgroup_bpf by 504 bytes through refactoring, from Dave Marchevsky.

10) Fix a smatch complaint in verifier's narrow load handling, from Andrey Ignatov.

11) Fix BPF interpreter's tail call count limit, from Daniel Borkmann.

12) Big batch of improvements to BPF selftests, from Magnus Karlsson, Li Zhijian,
    Yucong Sun, Yonghong Song, Ilya Leoshkevich, Jussi Maki, Ilya Leoshkevich, others.

13) Another big batch to revamp XDP samples in order to give them consistent look
    and feel, from Kumar Kartikeya Dwivedi.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (116 commits)
  MAINTAINERS: Remove self from powerpc BPF JIT
  selftests/bpf: Fix potential unreleased lock
  samples: bpf: Fix uninitialized variable in xdp_redirect_cpu
  selftests/bpf: Reduce more flakyness in sockmap_listen
  bpf: Fix bpf-next builds without CONFIG_BPF_EVENTS
  bpf: selftests: Add dctcp fallback test
  bpf: selftests: Add connect_to_fd_opts to network_helpers
  bpf: selftests: Add sk_state to bpf_tcp_helpers.h
  bpf: tcp: Allow bpf-tcp-cc to call bpf_(get|set)sockopt
  selftests: xsk: Preface options with opt
  selftests: xsk: Make enums lower case
  selftests: xsk: Generate packets from specification
  selftests: xsk: Generate packet directly in umem
  selftests: xsk: Simplify cleanup of ifobjects
  selftests: xsk: Decrease sending speed
  selftests: xsk: Validate tx stats on tx thread
  selftests: xsk: Simplify packet validation in xsk tests
  selftests: xsk: Rename worker_* functions that are not thread entry points
  selftests: xsk: Disassociate umem size with packets sent
  selftests: xsk: Remove end-of-test packet
  ...
====================

Link: https://lore.kernel.org/r/20210830225618.11634-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-30 16:42:47 -07:00
Maxim Mikityanskiy
ca49bfd90a sch_htb: Fix inconsistency when leaf qdisc creation fails
In HTB offload mode, qdiscs of leaf classes are grafted to netdev
queues. sch_htb expects the dev_queue field of these qdiscs to point to
the corresponding queues. However, qdisc creation may fail, and in that
case noop_qdisc is used instead. Its dev_queue doesn't point to the
right queue, so sch_htb can lose track of used netdev queues, which will
cause internal inconsistencies.

This commit fixes this bug by keeping track of the netdev queue inside
struct htb_class. All reads of cl->leaf.q->dev_queue are replaced by the
new field, the two values are synced on writes, and WARNs are added to
assert equality of the two values.

The driver API has changed: when TC_HTB_LEAF_DEL needs to move a queue,
the driver used to pass the old and new queue IDs to sch_htb. Now that
there is a new field (offload_queue) in struct htb_class that needs to
be updated on this operation, the driver will pass the old class ID to
sch_htb instead (it already knows the new class ID).

Fixes: d03b195b5a ("sch_htb: Hierarchical QoS hardware offload")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20210826115425.1744053-1-maximmi@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-30 16:33:59 -07:00
Haimin Zhang
efe487fce3 fix array-index-out-of-bounds in taprio_change
syzbot report an array-index-out-of-bounds in taprio_change
index 16 is out of range for type '__u16 [16]'
that's because mqprio->num_tc is lager than TC_MAX_QUEUE,so we check
the return value of netdev_set_num_tc.

Reported-by: syzbot+2b3e5fb6c7ef285a94f6@syzkaller.appspotmail.com
Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-30 12:24:40 +01:00
Jakub Kicinski
97c78d0af5 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/wwan/mhi_wwan_mbim.c - drop the extra arg.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-26 17:57:57 -07:00
Davide Caratti
cd9b50adc6 net/sched: ets: fix crash when flipping from 'strict' to 'quantum'
While running kselftests, Hangbin observed that sch_ets.sh often crashes,
and splats like the following one are seen in the output of 'dmesg':

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 159f12067 P4D 159f12067 PUD 159f13067 PMD 0
 Oops: 0000 [#1] SMP NOPTI
 CPU: 2 PID: 921 Comm: tc Not tainted 5.14.0-rc6+ #458
 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
 RIP: 0010:__list_del_entry_valid+0x2d/0x50
 Code: 48 8b 57 08 48 b9 00 01 00 00 00 00 ad de 48 39 c8 0f 84 ac 6e 5b 00 48 b9 22 01 00 00 00 00 ad de 48 39 ca 0f 84 cf 6e 5b 00 <48> 8b 32 48 39 fe 0f 85 af 6e 5b 00 48 8b 50 08 48 39 f2 0f 85 94
 RSP: 0018:ffffb2da005c3890 EFLAGS: 00010217
 RAX: 0000000000000000 RBX: ffff9073ba23f800 RCX: dead000000000122
 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff9073ba23fbc8
 RBP: ffff9073ba23f890 R08: 0000000000000001 R09: 0000000000000001
 R10: 0000000000000001 R11: 0000000000000001 R12: dead000000000100
 R13: ffff9073ba23fb00 R14: 0000000000000002 R15: 0000000000000002
 FS:  00007f93e5564e40(0000) GS:ffff9073bba00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 000000014ad34000 CR4: 0000000000350ee0
 Call Trace:
  ets_qdisc_reset+0x6e/0x100 [sch_ets]
  qdisc_reset+0x49/0x1d0
  tbf_reset+0x15/0x60 [sch_tbf]
  qdisc_reset+0x49/0x1d0
  dev_reset_queue.constprop.42+0x2f/0x90
  dev_deactivate_many+0x1d3/0x3d0
  dev_deactivate+0x56/0x90
  qdisc_graft+0x47e/0x5a0
  tc_get_qdisc+0x1db/0x3e0
  rtnetlink_rcv_msg+0x164/0x4c0
  netlink_rcv_skb+0x50/0x100
  netlink_unicast+0x1a5/0x280
  netlink_sendmsg+0x242/0x480
  sock_sendmsg+0x5b/0x60
  ____sys_sendmsg+0x1f2/0x260
  ___sys_sendmsg+0x7c/0xc0
  __sys_sendmsg+0x57/0xa0
  do_syscall_64+0x3a/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f93e44b8338
 Code: 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 43 2c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 41 89 d4 55
 RSP: 002b:00007ffc0db737a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
 RAX: ffffffffffffffda RBX: 0000000061255c06 RCX: 00007f93e44b8338
 RDX: 0000000000000000 RSI: 00007ffc0db73810 RDI: 0000000000000003
 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
 R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000001
 R13: 0000000000687880 R14: 0000000000000000 R15: 0000000000000000
 Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt iTCO_vendor_support intel_rapl_msr intel_rapl_common joydev i2c_i801 pcspkr i2c_smbus lpc_ich virtio_balloon ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel ahci libahci ghash_clmulni_intel libata serio_raw virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod
 CR2: 0000000000000000

When the change() function decreases the value of 'nstrict', we must take
into account that packets might be already enqueued on a class that flips
from 'strict' to 'quantum': otherwise that class will not be added to the
bandwidth-sharing list. Then, a call to ets_qdisc_reset() will attempt to
do list_del(&alist) with 'alist' filled with zero, hence the NULL pointer
dereference.
For classes flipping from 'strict' to 'quantum', initialize an empty list
and eventually add it to the bandwidth-sharing list, if there are packets
already enqueued. In this way, the kernel will:
 a) prevent crashing as described above.
 b) avoid retaining the backlog packets (for an arbitrarily long time) in
    case no packet is enqueued after a change from 'strict' to 'quantum'.

Reported-by: Hangbin Liu <liuhangbin@gmail.com>
Fixes: dcc68b4d80 ("net: sch_ets: Add a new Qdisc")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-25 11:15:30 +01:00
Jakub Kicinski
f444fea789 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/ptp/Kconfig:
  55c8fca1da ("ptp_pch: Restore dependency on PCI")
  e5f3155267 ("ethernet: fix PTP_1588_CLOCK dependencies")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-19 18:09:18 -07:00
Eli Cohen
74fc4f8287 net: Fix offloading indirect devices dependency on qdisc order creation
Currently, when creating an ingress qdisc on an indirect device before
the driver registered for callbacks, the driver will not have a chance
to register its filter configuration callbacks.

To fix that, modify the code such that it keeps track of all the ingress
qdiscs that call flow_indr_dev_setup_offload(). When a driver calls
flow_indr_dev_register(),  go through the list of tracked ingress qdiscs
and call the driver callback entry point so as to give it a chance to
register its callback.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-19 13:19:30 +01:00
Toke Høiland-Jørgensen
86b9bbd332 sch_cake: fix srchost/dsthost hashing mode
When adding support for using the skb->hash value as the flow hash in CAKE,
I accidentally introduced a logic error that broke the host-only isolation
modes of CAKE (srchost and dsthost keywords). Specifically, the flow_hash
variable should stay initialised to 0 in cake_hash() in pure host-based
hashing mode. Add a check for this before using the skb->hash value as
flow_hash.

Fixes: b0c19ed608 ("sch_cake: Take advantage of skb->hash where appropriate")
Reported-by: Pete Heist <pete@heistp.net>
Tested-by: Pete Heist <pete@heistp.net>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-18 10:14:00 +01:00
Andrii Nakryiko
fb7dd8bca0 bpf: Refactor BPF_PROG_RUN into a function
Turn BPF_PROG_RUN into a proper always inlined function. No functional and
performance changes are intended, but it makes it much easier to understand
what's going on with how BPF programs are actually get executed. It's more
obvious what types and callbacks are expected. Also extra () around input
parameters can be dropped, as well as `__` variable prefixes intended to avoid
naming collisions, which makes the code simpler to read and write.

This refactoring also highlighted one extra issue. BPF_PROG_RUN is both
a macro and an enum value (BPF_PROG_RUN == BPF_PROG_TEST_RUN). Turning
BPF_PROG_RUN into a function causes naming conflict compilation error. So
rename BPF_PROG_RUN into lower-case bpf_prog_run(), similar to
bpf_prog_run_xdp(), bpf_prog_run_pin_on_cpu(), etc. All existing callers of
BPF_PROG_RUN, the macro, are switched to bpf_prog_run() explicitly.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210815070609.987780-2-andrii@kernel.org
2021-08-17 00:45:07 +02:00
Jakub Kicinski
f4083a752a Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Conflicts:

drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
  9e26680733 ("bnxt_en: Update firmware call to retrieve TX PTP timestamp")
  9e518f2580 ("bnxt_en: 1PPS functions to configure TSIO pins")
  099fdeda65 ("bnxt_en: Event handler for PPS events")

kernel/bpf/helpers.c
include/linux/bpf-cgroup.h
  a2baf4e8bb ("bpf: Fix potentially incorrect results with bpf_get_local_storage()")
  c7603cfa04 ("bpf: Add ambient BPF runtime context stored in current")

drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
  5957cc557d ("net/mlx5: Set all field of mlx5_irq before inserting it to the xarray")
  2d0b41a376 ("net/mlx5: Refcount mlx5_irq with integer")

MAINTAINERS
  7b637cd52f ("MAINTAINERS: fix Microchip CAN BUS Analyzer Tool entry typo")
  7d901a1e87 ("net: phy: add Maxlinear GPY115/21x/24x driver")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-13 06:41:22 -07:00
Mark Bloch
a5397d68b2 net/sched: cls_api, reset flags on replay
tc_new_tfilter() can replay a request if it got EAGAIN. The cited commit
didn't account for this when it converted TC action ->init() API
to use flags instead of parameters. This can lead to passing stale flags
down the call chain which results in trying to lock rtnl when it's
already locked, deadlocking the entire system.

Fix by making sure to reset flags on each replay.

============================================
WARNING: possible recursive locking detected
5.14.0-rc3-custom-49011-g3d2bbb4f104d #447 Not tainted
--------------------------------------------
tc/37605 is trying to acquire lock:
ffffffff841df2f0 (rtnl_mutex){+.+.}-{3:3}, at: tc_setup_cb_add+0x14b/0x4d0

but task is already holding lock:
ffffffff841df2f0 (rtnl_mutex){+.+.}-{3:3}, at: tc_new_tfilter+0xb12/0x22e0

other info that might help us debug this:
 Possible unsafe locking scenario:
       CPU0
       ----
  lock(rtnl_mutex);
  lock(rtnl_mutex);

 *** DEADLOCK ***
 May be due to missing lock nesting notation
1 lock held by tc/37605:
 #0: ffffffff841df2f0 (rtnl_mutex){+.+.}-{3:3}, at: tc_new_tfilter+0xb12/0x22e0

stack backtrace:
CPU: 0 PID: 37605 Comm: tc Not tainted 5.14.0-rc3-custom-49011-g3d2bbb4f104d #447
Hardware name: Mellanox Technologies Ltd. MSN2010/SA002610, BIOS 5.6.5 08/24/2017
Call Trace:
 dump_stack_lvl+0x8b/0xb3
 __lock_acquire.cold+0x175/0x3cb
 lock_acquire+0x1a4/0x4f0
 __mutex_lock+0x136/0x10d0
 fl_hw_replace_filter+0x458/0x630 [cls_flower]
 fl_change+0x25f2/0x4a64 [cls_flower]
 tc_new_tfilter+0xa65/0x22e0
 rtnetlink_rcv_msg+0x86c/0xc60
 netlink_rcv_skb+0x14d/0x430
 netlink_unicast+0x539/0x7e0
 netlink_sendmsg+0x84d/0xd80
 ____sys_sendmsg+0x7ff/0x970
 ___sys_sendmsg+0xf8/0x170
 __sys_sendmsg+0xea/0x1b0
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f7b93b6c0a7
Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48>
RSP: 002b:00007ffe365b3818 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7b93b6c0a7
RDX: 0000000000000000 RSI: 00007ffe365b3880 RDI: 0000000000000003
RBP: 00000000610a75f6 R08: 0000000000000001 R09: 0000000000000000
R10: fffffffffffff3a9 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007ffe365b7b58 R15: 00000000004822c0

Fixes: 695176bfe5 ("net_sched: refactor TC action init API")
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Reviewed-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20210810034305.63997-1-mbloch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-10 16:01:17 -07:00
Hangbin Liu
d09c548dbf net: sched: act_mirred: Reset ct info when mirror/redirect skb
When mirror/redirect a skb to a different port, the ct info should be reset
for reclassification. Or the pkts will match unexpected rules. For example,
with following topology and commands:

    -----------
              |
       veth0 -+-------
              |
       veth1 -+-------
              |
   ------------

 tc qdisc add dev veth0 clsact
 # The same with "action mirred egress mirror dev veth1" or "action mirred ingress redirect dev veth1"
 tc filter add dev veth0 egress chain 1 protocol ip flower ct_state +trk action mirred ingress mirror dev veth1
 tc filter add dev veth0 egress chain 0 protocol ip flower ct_state -inv action ct commit action goto chain 1
 tc qdisc add dev veth1 clsact
 tc filter add dev veth1 ingress chain 0 protocol ip flower ct_state +trk action drop

 ping <remove ip via veth0> &
 tc -s filter show dev veth1 ingress

With command 'tc -s filter show', we can find the pkts were dropped on
veth1.

Fixes: b57dc7c13e ("net/sched: Introduce action ct")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-09 10:58:47 +01:00
Jakub Kicinski
0ca8d3ca45 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Build failure in drivers/net/wwan/mhi_wwan_mbim.c:
add missing parameter (0, assuming we don't want buffer pre-alloc).

Conflict in drivers/net/dsa/sja1105/sja1105_main.c between:
  589918df93 ("net: dsa: sja1105: be stateless with FDB entries on SJA1105P/Q/R/S/SJA1110 too")
  0fac6aa098 ("net: dsa: sja1105: delete the best_effort_vlan_filtering mode")

Follow the instructions from the commit message of the former commit
- removed the if conditions. When looking at commit 589918df93 ("net:
dsa: sja1105: be stateless with FDB entries on SJA1105P/Q/R/S/SJA1110 too")
note that the mask_iotag fields get removed by the following patch.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-05 15:08:47 -07:00
Yajun Deng
1160dfa178 net: Remove redundant if statements
The 'if (dev)' statement already move into dev_{put , hold}, so remove
redundant if statements.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-05 13:27:50 +01:00
Yunsheng Lin
06f5553e0f net: sched: fix lockdep_set_class() typo error for sch->seqlock
According to comment in qdisc_alloc(), sch->seqlock's lockdep
class key should be set to qdisc_tx_busylock, due to possible
type error, sch->busylock's lockdep class key is set to
qdisc_tx_busylock, which is duplicated because sch->busylock's
lockdep class key is already set in qdisc_alloc().

So fix it by replacing sch->busylock with sch->seqlock.

Fixes: 96009c7d50 ("sched: replace __QDISC_STATE_RUNNING bit with a spin lock")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-04 09:59:24 +01:00
Yannick Vignon
ebca25ead0 net/sched: taprio: Fix init procedure
Commit 13511704f8 ("net: taprio offload: enforce qdisc to netdev queue mapping")
resulted in duplicate entries in the qdisc hash.
While this did not impact the overall operation of the qdisc and taprio
code paths, it did result in an infinite loop when dumping the qdisc
properties, at least on one target (NXP LS1028 ARDB).
Removing the duplicate call to qdisc_hash_add() solves the problem.

Fixes: 13511704f8 ("net: taprio offload: enforce qdisc to netdev queue mapping")
Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-02 11:47:35 +01:00
Cong Wang
695176bfe5 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>
2021-08-02 10:24:38 +01:00
Davide Caratti
3aa2605594 net/sched: store the last executed chain also for clsact egress
currently, only 'ingress' and 'clsact ingress' qdiscs store the tc 'chain
id' in the skb extension. However, userspace programs (like ovs) are able
to setup egress rules, and datapath gets confused in case it doesn't find
the 'chain id' for a packet that's "recirculated" by tc.
Change tcf_classify() to have the same semantic as tcf_classify_ingress()
so that a single function can be called in ingress / egress, using the tc
ingress / egress block respectively.

Suggested-by: Alaa Hleilel <alaa@nvidia.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-29 22:17:37 +01:00
Peilin Ye
56af5e749f net/sched: act_skbmod: Add SKBMOD_F_ECN option support
Currently, when doing rate limiting using the tc-police(8) action, the
easiest way is to simply drop the packets which exceed or conform the
configured bandwidth limit.  Add a new option to tc-skbmod(8), so that
users may use the ECN [1] extension to explicitly inform the receiver
about the congestion instead of dropping packets "on the floor".

The 2 least significant bits of the Traffic Class field in IPv4 and IPv6
headers are used to represent different ECN states [2]:

	0b00: "Non ECN-Capable Transport", Non-ECT
	0b10: "ECN Capable Transport", ECT(0)
	0b01: "ECN Capable Transport", ECT(1)
	0b11: "Congestion Encountered", CE

As an example:

	$ tc filter add dev eth0 parent 1: protocol ip prio 10 \
		matchall action skbmod ecn

Doing the above marks all ECT(0) and ECT(1) packets as CE.  It does NOT
affect Non-ECT or non-IP packets.  In the tc-police scenario mentioned
above, users may pipe a tc-police action and a tc-skbmod "ecn" action
together to achieve ECN-based rate limiting.

For TCP connections, upon receiving a CE packet, the receiver will respond
with an ECE packet, asking the sender to reduce their congestion window.
However ECN also works with other L4 protocols e.g. DCCP and SCTP [2], and
our implementation does not touch or care about L4 headers.

The updated tc-skbmod SYNOPSIS looks like the following:

	tc ... action skbmod { set SETTABLE | swap SWAPPABLE | ecn } ...

Only one of "set", "swap" or "ecn" shall be used in a single tc-skbmod
command.  Trying to use more than one of them at a time is considered
undefined behavior; pipe multiple tc-skbmod commands together instead.
"set" and "swap" only affect Ethernet packets, while "ecn" only affects
IPv{4,6} packets.

It is also worth mentioning that, in theory, the same effect could be
achieved by piping a "police" action and a "bpf" action using the
bpf_skb_ecn_set_ce() helper, but this requires eBPF programming from the
user, thus impractical.

Depends on patch "net/sched: act_skbmod: Skip non-Ethernet packets".

[1] https://datatracker.ietf.org/doc/html/rfc3168
[2] https://en.wikipedia.org/wiki/Explicit_Congestion_Notification

Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-28 13:19:31 +01:00