We have observed meters working unexpected if traffic is 3+Gbit/s
with multiple connections.

now_ms is not pretected by meter->lock, we may get a negative
long_delta_ms when another cpu updated meter->used, then:
    delta_ms = (u32)long_delta_ms;
which will be a large value.

    band->bucket += delta_ms * band->rate;
then we get a wrong band->bucket.

OpenVswitch userspace datapath has fixed the same issue[1] some
time ago, and we port the implementation to kernel datapath.

[1] https://patchwork.ozlabs.org/project/openvswitch/patch/20191025114436.9746-1-i.maximets@ovn.org/

Fixes: 96fbc13d7e77 ("openvswitch: Add meter infrastructure")
Signed-off-by: Tao Liu <thomas.liu@ucloud.cn>
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

running openvswitch on kernels built with KASAN, it's possible to see the
following splat while testing fragmentation of IPv4 packets:

 BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60
 Read of size 1 at addr ffff888112fc713c by task handler2/1367

 CPU: 0 PID: 1367 Comm: handler2 Not tainted 5.12.0-rc6+ #418
 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
 Call Trace:
  dump_stack+0x92/0xc1
  print_address_description.constprop.7+0x1a/0x150
  kasan_report.cold.13+0x7f/0x111
  ip_do_fragment+0x1b03/0x1f60
  ovs_fragment+0x5bf/0x840 [openvswitch]
  do_execute_actions+0x1bd5/0x2400 [openvswitch]
  ovs_execute_actions+0xc8/0x3d0 [openvswitch]
  ovs_packet_cmd_execute+0xa39/0x1150 [openvswitch]
  genl_family_rcv_msg_doit.isra.15+0x227/0x2d0
  genl_rcv_msg+0x287/0x490
  netlink_rcv_skb+0x120/0x380
  genl_rcv+0x24/0x40
  netlink_unicast+0x439/0x630
  netlink_sendmsg+0x719/0xbf0
  sock_sendmsg+0xe2/0x110
  ____sys_sendmsg+0x5ba/0x890
  ___sys_sendmsg+0xe9/0x160
  __sys_sendmsg+0xd3/0x170
  do_syscall_64+0x33/0x40
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f957079db07
 Code: c3 66 90 41 54 41 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 eb ec ff ff 44 89 e2 48 89 ee 89 df 41 89 c0 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 24 ed ff ff 48
 RSP: 002b:00007f956ce35a50 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
 RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 00007f957079db07
 RDX: 0000000000000000 RSI: 00007f956ce35ae0 RDI: 0000000000000019
 RBP: 00007f956ce35ae0 R08: 0000000000000000 R09: 00007f9558006730
 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
 R13: 00007f956ce37308 R14: 00007f956ce35f80 R15: 00007f956ce35ae0

 The buggy address belongs to the page:
 page:00000000af2a1d93 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112fc7
 flags: 0x17ffffc0000000()
 raw: 0017ffffc0000000 0000000000000000 dead000000000122 0000000000000000
 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
 page dumped because: kasan: bad access detected

 addr ffff888112fc713c is located in stack of task handler2/1367 at offset 180 in frame:
  ovs_fragment+0x0/0x840 [openvswitch]

 this frame has 2 objects:
  [32, 144) 'ovs_dst'
  [192, 424) 'ovs_rt'

 Memory state around the buggy address:
  ffff888112fc7000: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff888112fc7080: 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00 00 00 00
 >ffff888112fc7100: 00 00 00 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00
                                         ^
  ffff888112fc7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff888112fc7200: 00 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00

for IPv4 packets, ovs_fragment() uses a temporary struct dst_entry. Then,
in the following call graph:

  ip_do_fragment()
    ip_skb_dst_mtu()
      ip_dst_mtu_maybe_forward()
        ip_mtu_locked()

the pointer to struct dst_entry is used as pointer to struct rtable: this
turns the access to struct members like rt_mtu_locked into an OOB read in
the stack. Fix this changing the temporary variable used for IPv4 packets
in ovs_fragment(), similarly to what is done for IPv6 few lines below.

Fixes: d52e5a7e7ca4 ("ipv4: lock mtu in fnhe when received PMTU < net.ipv4.route.min_pmt")
Cc: <stable@vger.kernel.org>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Implementation of meters supposed to be a classic token bucket with 2
typical parameters: rate and burst size.

Burst size in this schema is the maximum number of bytes/packets that
could pass without being rate limited.

Recent changes to userspace datapath made meter implementation to be
in line with the kernel one, and this uncovered several issues.

The main problem is that maximum bucket size for unknown reason
accounts not only burst size, but also the numerical value of rate.
This creates a lot of confusion around behavior of meters.

For example, if rate is configured as 1000 pps and burst size set to 1,
this should mean that meter will tolerate bursts of 1 packet at most,
i.e. not a single packet above the rate should pass the meter.
However, current implementation calculates maximum bucket size as
(rate + burst size), so the effective bucket size will be 1001.  This
means that first 1000 packets will not be rate limited and average
rate might be twice as high as the configured rate.  This also makes
it practically impossible to configure meter that will have burst size
lower than the rate, which might be a desirable configuration if the
rate is high.

Inability to configure low values of a burst size and overall inability
for a user to predict what will be a maximum and average rate from the
configured parameters of a meter without looking at the OVS and kernel
code might be also classified as a security issue, because drop meters
are frequently used as a way of protection from DoS attacks.

This change removes rate from the calculation of a bucket size, making
it in line with the classic token bucket algorithm and essentially
making the rate and burst tolerance being predictable from a users'
perspective.

Same change proposed for the userspace implementation.

Fixes: 96fbc13d7e77 ("openvswitch: Add meter infrastructure")
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:

MAINTAINERS
 - keep Chandrasekar
drivers/net/ethernet/mellanox/mlx5/core/en_main.c
 - simple fix + trust the code re-added to param.c in -next is fine
include/linux/bpf.h
 - trivial
include/linux/ethtool.h
 - trivial, fix kdoc while at it
include/linux/skmsg.h
 - move to relevant place in tcp.c, comment re-wrapped
net/core/skmsg.c
 - add the sk = sk // sk = NULL around calls
net/tipc/crypto.c
 - trivial

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

'struct ovs_zone_limit' has more members than initialized in
ovs_ct_limit_get_default_limit().  The rest of the memory is a random
kernel stack content that ends up being sent to userspace.

Fix that by using designated initializer that will clear all
non-specified fields.

Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

'skb_push()'/'skb_postpush_rcsum()' can be replaced by an equivalent
'skb_push_rcsum()' which is less verbose.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: David S. Miller <davem@davemloft.net>

s/subsytem/subsystem/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

It is not unusual to have the bridge port down. Sometimes
it has the old MTU, which is fine since it's not being used.

However, the kernel spams the log with a warning message
when a packet is going to be sent over such port. Fix that
by warning only if the interface is UP.

Signed-off-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: David S. Miller <davem@davemloft.net>