Commit Graph

97 Commits

Author SHA1 Message Date
Jakub Kicinski
9c5d03d362 genetlink: start to validate reserved header bytes
We had historically not checked that genlmsghdr.reserved
is 0 on input which prevents us from using those precious
bytes in the future.

One use case would be to extend the cmd field, which is
currently just 8 bits wide and 256 is not a lot of commands
for some core families.

To make sure that new families do the right thing by default
put the onus of opting out of validation on existing families.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel)
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-29 12:47:15 +01:00
Wolfram Sang
70986397a1 net: move from strlcpy with unused retval to strscpy
Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220818210215.8395-1-wsa+renesas@sang-engineering.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-22 18:06:18 -07:00
Eric Dumazet
c6cce71e74 drop_monitor: adopt u64_stats_t
As explained in commit 316580b69d ("u64_stats: provide u64_stats_t type")
we should use u64_stats_t and related accessors to avoid load/store tearing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09 21:53:12 -07:00
Jakub Kicinski
d62607c3fe net: rename reference+tracking helpers
Netdev reference helpers have a dev_ prefix for historic
reasons. Renaming the old helpers would be too much churn
but we can rename the tracking ones which are relatively
recent and should be the default for new code.

Rename:
 dev_hold_track()    -> netdev_hold()
 dev_put_track()     -> netdev_put()
 dev_replace_track() -> netdev_ref_replace()

Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09 21:52:55 -07:00
Menglong Dong
ec43908dd5 net: skb: use auto-generation to convert skb drop reason to string
It is annoying to add new skb drop reasons to 'enum skb_drop_reason'
and TRACE_SKB_DROP_REASON in trace/event/skb.h, and it's easy to forget
to add the new reasons we added to TRACE_SKB_DROP_REASON.

TRACE_SKB_DROP_REASON is used to convert drop reason of type number
to string. For now, the string we passed to user space is exactly the
same as the name in 'enum skb_drop_reason' with a 'SKB_DROP_REASON_'
prefix. Therefore, we can use 'auto-generation' to generate these
drop reasons to string at build time.

The new source 'dropreason_str.c' will be auto generated during build
time, which contains the string array
'const char * const drop_reasons[]'.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-06-07 12:51:41 +02:00
Menglong Dong
a3af33abd9 net: dm: check the boundary of skb drop reasons
The 'reason' will be set to 'SKB_DROP_REASON_NOT_SPECIFIED' if it not
small that SKB_DROP_REASON_MAX in net_dm_packet_trace_kfree_skb_hit(),
but it can't avoid it to be 0, which is invalid and can cause NULL
pointer in drop_reasons.

Therefore, reset it to SKB_DROP_REASON_NOT_SPECIFIED when 'reason <= 0'.

Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16 10:47:43 +01:00
Eric Dumazet
b26ef81c46 drop_monitor: remove quadratic behavior
drop_monitor is using an unique list on which all netdevices in
the host have an element, regardless of their netns.

This scales poorly, not only at device unregister time (what I
caught during my netns dismantle stress tests), but also at packet
processing time whenever trace_napi_poll_hit() is called.

If the intent was to avoid adding one pointer in 'struct net_device'
then surely we prefer O(1) behavior.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-23 12:39:58 +00:00
Jakub Kicinski
6b5567b1b2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-17 11:44:20 -08:00
Eric Dumazet
dcd54265c8 drop_monitor: fix data-race in dropmon_net_event / trace_napi_poll_hit
trace_napi_poll_hit() is reading stat->dev while another thread can write
on it from dropmon_net_event()

Use READ_ONCE()/WRITE_ONCE() here, RCU rules are properly enforced already,
we only have to take care of load/store tearing.

BUG: KCSAN: data-race in dropmon_net_event / trace_napi_poll_hit

write to 0xffff88816f3ab9c0 of 8 bytes by task 20260 on cpu 1:
 dropmon_net_event+0xb8/0x2b0 net/core/drop_monitor.c:1579
 notifier_call_chain kernel/notifier.c:84 [inline]
 raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:392
 call_netdevice_notifiers_info net/core/dev.c:1919 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:1931 [inline]
 call_netdevice_notifiers net/core/dev.c:1945 [inline]
 unregister_netdevice_many+0x867/0xfb0 net/core/dev.c:10415
 ip_tunnel_delete_nets+0x24a/0x280 net/ipv4/ip_tunnel.c:1123
 vti_exit_batch_net+0x2a/0x30 net/ipv4/ip_vti.c:515
 ops_exit_list net/core/net_namespace.c:173 [inline]
 cleanup_net+0x4dc/0x8d0 net/core/net_namespace.c:597
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

read to 0xffff88816f3ab9c0 of 8 bytes by interrupt on cpu 0:
 trace_napi_poll_hit+0x89/0x1c0 net/core/drop_monitor.c:292
 trace_napi_poll include/trace/events/napi.h:14 [inline]
 __napi_poll+0x36b/0x3f0 net/core/dev.c:6366
 napi_poll net/core/dev.c:6432 [inline]
 net_rx_action+0x29e/0x650 net/core/dev.c:6519
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 do_softirq+0xb1/0xf0 kernel/softirq.c:459
 __local_bh_enable_ip+0x68/0x70 kernel/softirq.c:383
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x33/0x40 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:394 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
 wg_packet_decrypt_worker+0x73c/0x780 drivers/net/wireguard/receive.c:506
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

value changed: 0xffff88815883e000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26435 Comm: kworker/0:1 Not tainted 5.17.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-crypt-wg2 wg_packet_decrypt_worker

Fixes: 4ea7e38696 ("dropmon: add ability to detect when hardware dropsrxpackets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-11 11:20:32 +00:00
Menglong Dong
5cad527d5f net: drop_monitor: support drop reason
In the commit c504e5c2f9 ("net: skb: introduce kfree_skb_reason()")
drop reason is introduced to the tracepoint of kfree_skb. Therefore,
drop_monitor is able to report the drop reason to users by netlink.

The drop reasons are reported as string to users, which is exactly
the same as what we do when reporting it to ftrace.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220209060838.55513-1-imagedong@tencent.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-09 17:25:57 -08:00
Menglong Dong
c504e5c2f9 net: skb: introduce kfree_skb_reason()
Introduce the interface kfree_skb_reason(), which is able to pass
the reason why the skb is dropped to 'kfree_skb' tracepoint.

Add the 'reason' field to 'trace_kfree_skb', therefor user can get
more detail information about abnormal skb with 'drop_monitor' or
eBPF.

All drop reasons are defined in the enum 'skb_drop_reason', and
they will be print as string in 'kfree_skb' tracepoint in format
of 'reason: XXX'.

( Maybe the reasons should be defined in a uapi header file, so that
user space can use them? )

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-09 16:30:34 -08:00
Eric Dumazet
4dbd24f65c drop_monitor: add net device refcount tracker
We want to track all dev_hold()/dev_put() to ease leak hunting.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-06 16:05:10 -08:00
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
David S. Miller
efd13b71a3 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-25 15:31:22 -07:00
Xiong Zhenwu
a835f9034e /net/core/: fix misspellings using codespell tool
A typo is found out by codespell tool in 1734th line of drop_monitor.c:

$ codespell ./net/core/
./net/core/drop_monitor.c:1734: guarnateed  ==> guaranteed

Fix a typo found by codespell.

Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-18 19:13:41 -07:00
Ido Schimmel
9398e9c0b1 drop_monitor: Perform cleanup upon probe registration failure
In the rare case that drop_monitor fails to register its probe on the
'napi_poll' tracepoint, it will not deactivate its hysteresis timer as
part of the error path. If the hysteresis timer was armed by the shortly
lived 'kfree_skb' probe and user space retries to initiate tracing, a
warning will be emitted for trying to initialize an active object [1].

Fix this by properly undoing all the operations that were done prior to
probe registration, in both software and hardware code paths.

Note that syzkaller managed to fail probe registration by injecting a
slab allocation failure [2].

[1]
ODEBUG: init active (active state 0) object type: timer_list hint: sched_send_work+0x0/0x60 include/linux/list.h:135
WARNING: CPU: 1 PID: 8649 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Modules linked in:
CPU: 1 PID: 8649 Comm: syz-executor.0 Not tainted 5.11.0-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
[...]
Call Trace:
 __debug_object_init+0x524/0xd10 lib/debugobjects.c:588
 debug_timer_init kernel/time/timer.c:722 [inline]
 debug_init kernel/time/timer.c:770 [inline]
 init_timer_key+0x2d/0x340 kernel/time/timer.c:814
 net_dm_trace_on_set net/core/drop_monitor.c:1111 [inline]
 set_all_monitor_traces net/core/drop_monitor.c:1188 [inline]
 net_dm_monitor_start net/core/drop_monitor.c:1295 [inline]
 net_dm_cmd_trace+0x720/0x1220 net/core/drop_monitor.c:1339
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739
 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
 genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2348
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2402
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2435
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

[2]
 FAULT_INJECTION: forcing a failure.
 name failslab, interval 1, probability 0, space 0, times 1
 CPU: 1 PID: 8645 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 Call Trace:
  dump_stack+0xfa/0x151
  should_fail.cold+0x5/0xa
  should_failslab+0x5/0x10
  __kmalloc+0x72/0x3f0
  tracepoint_add_func+0x378/0x990
  tracepoint_probe_register+0x9c/0xe0
  net_dm_cmd_trace+0x7fc/0x1220
  genl_family_rcv_msg_doit+0x228/0x320
  genl_rcv_msg+0x328/0x580
  netlink_rcv_skb+0x153/0x420
  genl_rcv+0x24/0x40
  netlink_unicast+0x533/0x7d0
  netlink_sendmsg+0x856/0xd90
  sock_sendmsg+0xcf/0x120
  ____sys_sendmsg+0x6e8/0x810
  ___sys_sendmsg+0xf3/0x170
  __sys_sendmsg+0xe5/0x1b0
  do_syscall_64+0x2d/0x70
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 70c69274f3 ("drop_monitor: Initialize timer and work item upon tracing enable")
Fixes: 8ee2267ad3 ("drop_monitor: Convert to using devlink tracepoint")
Reported-by: syzbot+779559d6503f3a56213d@syzkaller.appspotmail.com
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-10 15:19:02 -08:00
Jakub Kicinski
66a9b9287d genetlink: move to smaller ops wherever possible
Bulk of the genetlink users can use smaller ops, move them.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-02 19:11:11 -07:00
Ido Schimmel
93e155967c drop_monitor: Filter control packets in drop monitor
Previously, devlink called into drop monitor in order to report hardware
originated drops / exceptions. devlink intentionally filtered control
packets and did not pass them to drop monitor as they were not dropped
by the underlying hardware.

Now drop monitor registers its probe on a generic 'devlink_trap_report'
tracepoint and should therefore perform this filtering itself instead of
having devlink do that.

Add the trap type as metadata and have drop monitor ignore control
packets.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Ido Schimmel
a848c05f4b drop_monitor: Remove duplicate struct
'struct net_dm_hw_metadata' is a duplicate of 'struct
devlink_trap_metadata'.

Remove the former and simplify the code.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Ido Schimmel
de9cbb81bd drop_monitor: Remove no longer used functions
The old probe functions that were invoked by drop monitor code are no
longer called and can thus be removed. They were replaced by actual
probe functions that are registered on the recently introduced
'devlink_trap_report' tracepoint.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Ido Schimmel
8ee2267ad3 drop_monitor: Convert to using devlink tracepoint
Convert drop monitor to use the recently introduced
'devlink_trap_report' tracepoint instead of having devlink call into
drop monitor.

This is both consistent with software originated drops ('kfree_skb'
tracepoint) and also allows drop monitor to be built as a module and
still report hardware originated drops.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Ido Schimmel
5855357cd4 drop_monitor: Prepare probe functions for devlink tracepoint
Drop monitor supports two alerting modes: Summary and packet. Prepare a
probe function for each, so that they could be later registered on the
devlink tracepoint by calling register_trace_devlink_trap_report(),
based on the configured alerting mode.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Gustavo A. R. Silva
df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Rob Gill
67c20de35a net: Add MODULE_DESCRIPTION entries to network modules
The user tool modinfo is used to get information on kernel modules, including a
description where it is available.

This patch adds a brief MODULE_DESCRIPTION to the following modules:

9p
drop_monitor
esp4_offload
esp6_offload
fou
fou6
ila
sch_fq
sch_fq_codel
sch_hhf

Signed-off-by: Rob Gill <rrobgill@protonmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-20 21:33:57 -07:00
Arnd Bergmann
dc30b4059f drop_monitor: work around gcc-10 stringop-overflow warning
The current gcc-10 snapshot produces a false-positive warning:

net/core/drop_monitor.c: In function 'trace_drop_common.constprop':
cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=]
In file included from net/core/drop_monitor.c:23:
include/uapi/linux/net_dropmon.h:36:8: note: at offset 0 to object 'entries' with size 4 declared here
   36 |  __u32 entries;
      |        ^~~~~~~

I reported this in the gcc bugzilla, but in case it does not get
fixed in the release, work around it by using a temporary variable.

Fixes: 9a8afc8d39 ("Network Drop Monitor: Adding drop monitor implementation & Netlink protocol")
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94881
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-01 15:45:16 -07:00
Gustavo A. R. Silva
d2afb41ae6 net: core: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-28 12:08:37 -08:00
Jiri Pirko
742b8cceaa drop_monitor: extend by passing cookie from driver
If driver passed along the cookie, push it through Netlink.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-25 11:05:54 -08:00
Ido Schimmel
dfa7f70959 drop_monitor: Do not cancel uninitialized work item
Drop monitor uses a work item that takes care of constructing and
sending netlink notifications to user space. In case drop monitor never
started to monitor, then the work item is uninitialized and not
associated with a function.

Therefore, a stop command from user space results in canceling an
uninitialized work item which leads to the following warning [1].

Fix this by not processing a stop command if drop monitor is not
currently monitoring.

[1]
[   31.735402] ------------[ cut here ]------------
[   31.736470] WARNING: CPU: 0 PID: 143 at kernel/workqueue.c:3032 __flush_work+0x89f/0x9f0
...
[   31.738120] CPU: 0 PID: 143 Comm: dwdump Not tainted 5.5.0-custom-09491-g16d4077796b8 #727
[   31.741968] RIP: 0010:__flush_work+0x89f/0x9f0
...
[   31.760526] Call Trace:
[   31.771689]  __cancel_work_timer+0x2a6/0x3b0
[   31.776809]  net_dm_cmd_trace+0x300/0xef0
[   31.777549]  genl_rcv_msg+0x5c6/0xd50
[   31.781005]  netlink_rcv_skb+0x13b/0x3a0
[   31.784114]  genl_rcv+0x29/0x40
[   31.784720]  netlink_unicast+0x49f/0x6a0
[   31.787148]  netlink_sendmsg+0x7cf/0xc80
[   31.790426]  ____sys_sendmsg+0x620/0x770
[   31.793458]  ___sys_sendmsg+0xfd/0x170
[   31.802216]  __sys_sendmsg+0xdf/0x1a0
[   31.806195]  do_syscall_64+0xa0/0x540
[   31.806885]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: 8e94c3bc92 ("drop_monitor: Allow user to start monitoring hardware drops")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-07 18:48:36 +01:00
Joe Perches
72d62c4e42 net: drop_monitor: Use kstrdup
Convert the equivalent but rather odd uses of kmemdup with
__GFP_ZERO to the more common kstrdup and avoid unnecessary
zeroing of copied over memory.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-30 10:03:37 +01:00
Ido Schimmel
bef1746681 drop_monitor: Better sanitize notified packets
When working in 'packet' mode, drop monitor generates a notification
with a potentially truncated payload of the dropped packet. The payload
is copied from the MAC header, but I forgot to check that the MAC header
was set, so do it now.

Fixes: ca30707dee ("drop_monitor: Add packet alert mode")
Fixes: 5e58109b1e ("drop_monitor: Add support for packet alert mode for hardware drops")
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-16 21:39:27 +02:00
Ido Schimmel
bd1200b795 drop_monitor: Make timestamps y2038 safe
Timestamps are currently communicated to user space as 'struct
timespec', which is not considered y2038 safe since it uses a 32-bit
signed value for seconds.

Fix this while the API is still not part of any official kernel release
by using 64-bit nanoseconds timestamps instead.

Fixes: ca30707dee ("drop_monitor: Add packet alert mode")
Fixes: 5e58109b1e ("drop_monitor: Add support for packet alert mode for hardware drops")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-23 14:58:07 -07:00
Ido Schimmel
8e94c3bc92 drop_monitor: Allow user to start monitoring hardware drops
Drop monitor has start and stop commands, but so far these were only
used to start and stop monitoring of software drops.

Now that drop monitor can also monitor hardware drops, we should allow
the user to control these as well.

Do that by adding SW and HW flags to these commands. If no flag is
specified, then only start / stop monitoring software drops. This is
done in order to maintain backward-compatibility with existing user
space applications.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17 12:40:08 -07:00
Ido Schimmel
d40e1deb93 drop_monitor: Add support for summary alert mode for hardware drops
In summary alert mode a notification is sent with a list of recent drop
reasons and a count of how many packets were dropped due to this reason.

To avoid expensive operations in the context in which packets are
dropped, each CPU holds an array whose number of entries is the maximum
number of drop reasons that can be encoded in the netlink notification.
Each entry stores the drop reason and a count. When a packet is dropped
the array is traversed and a new entry is created or the count of an
existing entry is incremented.

Later, in process context, the array is replaced with a newly allocated
copy and the old array is encoded in a netlink notification. To avoid
breaking user space, the notification includes the ancillary header,
which is 'struct net_dm_alert_msg' with number of entries set to '0'.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17 12:40:08 -07:00
Ido Schimmel
5e58109b1e drop_monitor: Add support for packet alert mode for hardware drops
In a similar fashion to software drops, extend drop monitor to send
netlink events when packets are dropped by the underlying hardware.

The main difference is that instead of encoding the program counter (PC)
from which kfree_skb() was called in the netlink message, we encode the
hardware trap name. The two are mostly equivalent since they should both
help the user understand why the packet was dropped.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17 12:40:08 -07:00
Ido Schimmel
80cebed85c drop_monitor: Consider all monitoring states before performing configuration
The drop monitor configuration (e.g., alert mode) is global, but user
will be able to enable monitoring of only software or hardware drops.

Therefore, ensure that monitoring of both software and hardware drops are
disabled before allowing drop monitor configuration to take place.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17 12:40:08 -07:00
Ido Schimmel
edd3d0074c drop_monitor: Add basic infrastructure for hardware drops
Export a function that can be invoked in order to report packets that
were dropped by the underlying hardware along with metadata.

Subsequent patches will add support for the different alert modes.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17 12:40:08 -07:00
Ido Schimmel
cac1174fa1 drop_monitor: Initialize hardware per-CPU data
Like software drops, hardware drops also need the same type of per-CPU
data. Therefore, initialize it during module initialization and
de-initialize it during module exit.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17 12:40:08 -07:00
Ido Schimmel
9b63f57d4a drop_monitor: Move per-CPU data init/fini to separate functions
Currently drop monitor only reports software drops to user space, but
subsequent patches are going to add support for hardware drops.

Like software drops, the per-CPU data of hardware drops needs to be
initialized and de-initialized upon module initialization and exit. To
avoid code duplication, break this code into separate functions, so that
these could be re-used for hardware drops.

No functional changes intended.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-17 12:40:08 -07:00
Ido Schimmel
e9feb58020 drop_monitor: Expose tail drop counter
Previous patch made the length of the per-CPU skb drop list
configurable. Expose a counter that shows how many packets could not be
enqueued to this list.

This allows users determine the desired queue length.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
30328d46af drop_monitor: Make drop queue length configurable
In packet alert mode, each CPU holds a list of dropped skbs that need to
be processed in process context and sent to user space. To avoid
exhausting the system's memory the maximum length of this queue is
currently set to 1000.

Allow users to tune the length of this queue according to their needs.
The configured length is reported to user space when drop monitor
configuration is queried.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
444be061d0 drop_monitor: Add a command to query current configuration
Users should be able to query the current configuration of drop monitor
before they start using it. Add a command to query the existing
configuration which currently consists of alert mode and packet
truncation length.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
57986617a7 drop_monitor: Allow truncation of dropped packets
When sending dropped packets to user space it is not always necessary to
copy the entire packet as usually only the headers are of interest.

Allow user to specify the truncation length and add the original length
of the packet as additional metadata to the netlink message.

By default no truncation is performed.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
ca30707dee drop_monitor: Add packet alert mode
So far drop monitor supported only one alert mode in which a summary of
locations in which packets were recently dropped was sent to user space.

This alert mode is sufficient in order to understand that packets were
dropped, but lacks information to perform a more detailed analysis.

Add a new alert mode in which the dropped packet itself is passed to
user space along with metadata: The drop location (as program counter
and resolved symbol), ingress netdevice and drop timestamp. More
metadata can be added in the future.

To avoid performing expensive operations in the context in which
kfree_skb() is invoked (can be hard IRQ), the dropped skb is cloned and
queued on per-CPU skb drop list. Then, in process context the netlink
message is allocated, prepared and finally sent to user space.

The per-CPU skb drop list is limited to 1000 skbs to prevent exhausting
the system's memory. Subsequent patches will make this limit
configurable and also add a counter that indicates how many skbs were
tail dropped.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
28315f7999 drop_monitor: Add alert mode operations
The next patch is going to add another alert mode in which the dropped
packet is notified to user space, instead of only a summary of recent
drops.

Abstract the differences between the modes by adding alert mode
operations. The operations are selected based on the currently
configured mode and associated with the probes and the work item just
before tracing starts.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
c5ab9b1c41 drop_monitor: Require CAP_NET_ADMIN for drop monitor configuration
Currently, the configure command does not do anything but return an
error. Subsequent patches will enable the command to change various
configuration options such as alert mode and packet truncation.

Similar to other netlink-based configuration channels, make sure only
users with the CAP_NET_ADMIN capability set can execute this command.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
44075f5637 drop_monitor: Reset per-CPU data before starting to trace
The function reset_per_cpu_data() allocates and prepares a new skb for
the summary netlink alert message ('NET_DM_CMD_ALERT'). The new skb is
stored in the per-CPU 'data' variable and the old is returned.

The function is invoked during module initialization and from the
workqueue, before an alert is sent. This means that it is possible to
receive an alert with stale data, if we stopped tracing when the
hysteresis timer ('data->send_timer') was pending.

Instead of invoking the function during module initialization, invoke it
just before we start tracing and ensure we get a fresh skb.

This also allows us to remove the calls to initialize the timer and the
work item from the module initialization path, since both could have
been triggered by the error paths of reset_per_cpu_data().

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
70c69274f3 drop_monitor: Initialize timer and work item upon tracing enable
The timer and work item are currently initialized once during module
init, but subsequent patches will need to associate different functions
with the work item, based on the configured alert mode.

Allow subsequent patches to make that change by initializing and
de-initializing these objects during tracing enable and disable.

This also guarantees that once the request to disable tracing returns,
no more netlink notifications will be generated.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
7c747838a5 drop_monitor: Split tracing enable / disable to different functions
Subsequent patches will need to enable / disable tracing based on the
configured alerting mode.

Reduce the nesting level and prepare for the introduction of this
functionality by splitting the tracing enable / disable operations into
two different functions.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-11 10:53:30 -07:00
Ido Schimmel
b19d955055 drop_monitor: Use pre_doit / post_doit hooks
Each operation from user space should be protected by the global drop
monitor mutex. Use the pre_doit / post_doit hooks to take / release the
lock instead of doing it explicitly in each function.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-06 12:37:56 -07:00
Ido Schimmel
965100966e drop_monitor: Add extack support
Add various extack messages to make drop_monitor more user friendly.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-06 12:37:56 -07:00