Lipeng says:

====================
net: hns3: support set_link_ksettings and for nway_reset ethtool command

This patch-set adds support for set_link_ksettings && for nway_resets
ethtool command and fixes some related ethtool bugs.
1, patch[4/6] adds support for ethtool_ops.set_link_ksettings.
2, patch[5/6] adds support ethtool_ops.for nway_reset.
3, patch[1/6,2/6,3/6,6/6] fix some bugs for getting port information by
   ethtool command(ethtool ethx).
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a bug for phy supported feature initialization.
Currently, the value of phydev->supported is initialized by kernel.
So it includes many features that we do not support, such as
SUPPORTED_FIBRE and SUPPORTED_BNC. This patch fixes it.

Fixes: 256727da (net: hns3: Add MDIO support to HNS3 Ethernet driver for hip08 SoC)
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NLipeng <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds nway_reset support for ethtool cmd.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NLipeng <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds set_link_ksettings support for ethtool cmd.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NLipeng <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The value of link_modes.advertising and the value of link_modes.supported
is initialized to zero every time in for loop in hns3_driv_to_eth_caps().
But we just want to set specified bit for them. Initialization is
unnecessary. This patch fixes it.

Fixes: 496d03e9 (net: hns3: Add Ethtool support to HNS3 driver)
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NLipeng <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a bug for ethtool's get_link_ksettings().
The advertising for autoneg is always added to advertised_caps
whether autoneg is enable or disable. This patch fixes it.

Fixes: 496d03e9 (net: hns3: Add Ethtool support to HNS3 driver)
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NLipeng <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes a bug for ethtool's get_link_ksettings().
When phy exists, we should get autoneg from phy rather than from mac.
Because the value of mac.autoneg is invalid when phy exists.

Fixes: 496d03e9 (net: hns3: Add Ethtool support to HNS3 driver)
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NLipeng <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Michael Chan says:

====================
bnxt_en: Fix IRQ coalescing regressions.

There was a typo and missing guard-rail against illegal values in the
recent code clean up.  All reported by Andy Gospodarek.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Recent IRQ coalescing clean up has removed a guard-rail for the max DMA
buffer coalescing value.  This is a 6-bit value and must not be 0.  We
already have a check for 0 but 64 is equivalent to 0 and will cause
non-stop interrupts.  Fix it by adding the proper check.

Fixes: f8503969 ("bnxt_en: Refactor and simplify coalescing code.")
Reported-by: NAndy Gospodarek <gospo@broadcom.com>
Signed-off-by: NMichael Chan <michael.chan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Recent refactoring of coalesce settings contained a typo that prevents
receive settings from being set properly.

Fixes: 18775aa8 ("bnxt_en: Reorganize the coalescing parameters.")
Signed-off-by: NAndy Gospodarek <gospo@broadcom.com>
Signed-off-by: NMichael Chan <michael.chan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Callers of tcf_block_put() could pass NULL so
we can't use block->q before checking if block is
NULL or not.

tcf_block_put_ext() callers are fine, it is always
non-NULL.

Fixes: 8c4083b3 ("net: sched: add block bind/unbind notif. and extended block_get/put")
Reported-by: NDave Taht <dave.taht@gmail.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While stress testing MTU probing, we had crashes in list_del() that we root-caused
to the fact that tcp_fragment() is unconditionally inserting the freshly allocated
skb into tsorted_sent_queue list.

But this list is supposed to contain skbs that were sent.
This was mostly harmless until MTU probing was enabled.

Fortunately we can use the tcp_queue enum added later (but in same linux version)
for rtx-rb-tree to fix the bug.

Fixes: e2080072 ("tcp: new list for sent but unacked skbs for RACK recovery")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Priyaranjan Jha <priyarjha@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Geliang Tang <geliangtang@gmail.com>
Cc: netdev@vger.kernel.org
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 114780
Addresses-Coverity-ID: 114781
Addresses-Coverity-ID: 114782
Addresses-Coverity-ID: 114783
Addresses-Coverity-ID: 114784
Addresses-Coverity-ID: 114785
Addresses-Coverity-ID: 114786
Addresses-Coverity-ID: 114787
Addresses-Coverity-ID: 114788
Addresses-Coverity-ID: 114789
Addresses-Coverity-ID: 114790
Addresses-Coverity-ID: 114791
Addresses-Coverity-ID: 114792
Addresses-Coverity-ID: 114793
Addresses-Coverity-ID: 114794
Addresses-Coverity-ID: 114795
Addresses-Coverity-ID: 200521
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently gen_flags is being operated on by a logical && operator rather
than a bitwise & operator. This looks incorrect as these should be bit
flag operations. Fix this.

Detected by CoverityScan, CID#1460305 ("Logical vs. bitwise operator")

Fixes: 3f7889c4 ("net: sched: cls_bpf: call block callbacks for offload)
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

icsk_accept_queue.fastopenq.lock is only fully initialized at listen()
time.

LOCKDEP is not happy if we attempt a spin_lock_bh() on it, because
of missing annotation. (Although kernel runs just fine)

Lets use net->ipv4.tcp_fastopen_ctx_lock to protect ctx access.

Fixes: 1fba70e5 ("tcp: socket option to set TCP fast open key")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: NChristoph Paasch <cpaasch@apple.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

do_check() can fail early without allocating env->cur_state under
memory pressure.  Syzkaller found the stack below on the linux-next
tree because of this.

  kasan: CONFIG_KASAN_INLINE enabled
  kasan: GPF could be caused by NULL-ptr deref or user memory access
  general protection fault: 0000 [#1] SMP KASAN
  Dumping ftrace buffer:
     (ftrace buffer empty)
  Modules linked in:
  CPU: 1 PID: 27062 Comm: syz-executor5 Not tainted 4.14.0-rc7+ #106
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  task: ffff8801c2c74700 task.stack: ffff8801c3e28000
  RIP: 0010:free_verifier_state kernel/bpf/verifier.c:347 [inline]
  RIP: 0010:bpf_check+0xcf4/0x19c0 kernel/bpf/verifier.c:4533
  RSP: 0018:ffff8801c3e2f5c8 EFLAGS: 00010202
  RAX: dffffc0000000000 RBX: 00000000fffffff4 RCX: 0000000000000000
  RDX: 0000000000000070 RSI: ffffffff817d5aa9 RDI: 0000000000000380
  RBP: ffff8801c3e2f668 R08: 0000000000000000 R09: 1ffff100387c5d9f
  R10: 00000000218c4e80 R11: ffffffff85b34380 R12: ffff8801c4dc6a28
  R13: 0000000000000000 R14: ffff8801c4dc6a00 R15: ffff8801c4dc6a20
  FS:  00007f311079b700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000004d4a24 CR3: 00000001cbcd0000 CR4: 00000000001406e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   bpf_prog_load+0xcbb/0x18e0 kernel/bpf/syscall.c:1166
   SYSC_bpf kernel/bpf/syscall.c:1690 [inline]
   SyS_bpf+0xae9/0x4620 kernel/bpf/syscall.c:1652
   entry_SYSCALL_64_fastpath+0x1f/0xbe
  RIP: 0033:0x452869
  RSP: 002b:00007f311079abe8 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
  RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452869
  RDX: 0000000000000030 RSI: 0000000020168000 RDI: 0000000000000005
  RBP: 00007f311079aa20 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b7550
  R13: 00007f311079ab58 R14: 00000000004b7560 R15: 0000000000000000
  Code: df 48 c1 ea 03 80 3c 02 00 0f 85 e6 0b 00 00 4d 8b 6e 20 48 b8 00 00 00 00 00 fc ff df 49 8d bd 80 03 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b6 0b 00 00 49 8b bd 80 03 00 00 e8 d6 0c 26
  RIP: free_verifier_state kernel/bpf/verifier.c:347 [inline] RSP: ffff8801c3e2f5c8
  RIP: bpf_check+0xcf4/0x19c0 kernel/bpf/verifier.c:4533 RSP: ffff8801c3e2f5c8
  ---[ end trace c8d37f339dc64004 ]---

Fixes: 638f5b90 ("bpf: reduce verifier memory consumption")
Fixes: 1969db47 ("bpf: fix verifier memory leaks")
Signed-off-by: NCraig Gallek <kraig@google.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The neighbor monitor employs a threshold, default set to 32 peer nodes,
where it activates the "Overlapping Neighbor Monitoring" algorithm.
Below that threshold, monitoring is full-mesh, and no "domain records"
are passed between the nodes.

Because of this, a node never received a peer's ack that it has received
the most recent update of the own domain. Hence, the field 'acked_gen'
in struct tipc_monitor_state remains permamently at zero, whereas the
own domain generation is incremented for each added or removed peer.

This has the effect that the function tipc_mon_get_state() always sets
the field 'probing' in struct tipc_monitor_state true, again leading the
tipc_link_timeout() of the link in question to always send out a probe,
even when link->silent_intv_count is zero.

This is functionally harmless, but leads to some unncessary probing,
which can easily be eliminated by setting the 'probing' field of the
said struct correctly in such cases.

At the same time, we explictly invalidate the sent domain records when
the algorithm is not activated. This will eliminate any risk that an
invalid domain record might be inadverently accepted by the peer.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, the offload unbind is done before the chains are flushed.
That causes driver to unregister block callback before it can get all
the callback calls done during flush, leaving the offloaded tps inside
the HW. So fix the order to prevent this situation and restore the
original behaviour.
Reported-by: NAlexander Duyck <alexander.duyck@gmail.com>
Reported-by: NJakub Kicinski <kubakici@wp.pl>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support to new ethtool operation get_fecparam to
fetch FEC parameters.

Original Work by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: NGanesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add 0x6086 T6 device id.
Signed-off-by: NGanesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes the following sparse warnings:

net/ncsi/ncsi-manage.c:41:5: warning:
 symbol 'ncsi_get_filter' was not declared. Should it be static?
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

switch to using the new timer_setup() and from_timer() api's.
Signed-off-by: NAllen Pais <allen.pais@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

switch to using the new timer_setup() and from_timer() api's.
Signed-off-by: NAllen Pais <allen.pais@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jiri Pirko says:

====================
mlxsw: Align multipath hash parameters with kernel's

Ido says:

This set makes sure the device is using the same parameters as the
kernel when it computes the multipath hash during IP forwarding.

First patch adds a new netevent to let interested listeners know that
the multipath hash policy has changed.

Next two patches do small and non-functional changes in the mlxsw
driver.

Last patches configure the multipath hash policy upon driver
initialization and as a response to netevents.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make sure the device and the kernel are performing the multipath hash
according to the same parameters by updating the device whenever the
relevant netevent is generated.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Up until now we used the hardware's defaults for multipath hash
computation. This patch aligns the hardware's multipath parameters with
the kernel's.

For IPv4 packets, the parameters are determined according to the
'fib_multipath_hash_policy' sysctl during module initialization. In case
L3-mode is requested, only the source and destination IP addresses are
used. There is no special handling of ICMP error packets.

In case L4-mode is requested, a 5-tuple is used: source and destination
IP addresses, source and destination ports and IP protocol. Note that
the layer 4 fields are not considered for fragmented packets.

For IPv6 packets, the source and destination IP addresses are used, as
well as the flow label and the next header fields.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The RECRv2 register is used for setting up the router's ECMP hash
configuration.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The struct containing the work item queued from the netevent handler is
named after the only event it is currently used for, which is neighbour
updates.

Use a more appropriate name for the struct, as we are going to use it
for more events.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We are going to need to respond to netevents notifying us about
multipath hash updates by configuring the device's hash parameters.

Embed the netevent notifier in the router struct so that we could
retrieve it upon notifications and use it to configure the device.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Devices performing IPv4 forwarding need to update their multipath hash
policy whenever it is changed.

Inform these devices by generating a netevent.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix to return a negative error code from thecxgb4_alloc_atid()
error handling case instead of 0.

Fixes: 12b276fb ("cxgb4: add support to create hash filters")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-By: NKumar Sanghvi <kumaras@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The bpf_verifer_ops array is generated dynamically and may be
empty depending on configuration, which then causes an out
of bounds access:

kernel/bpf/verifier.c: In function 'bpf_check':
kernel/bpf/verifier.c:4320:29: error: array subscript is above array bounds [-Werror=array-bounds]

This adds a check to the start of the function as a workaround.
I would assume that the function is never called in that configuration,
so the warning is probably harmless.

Fixes: 00176a34 ("bpf: remove the verifier ops from program structure")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I ran into this link error with the latest net-next plus linux-next
trees when networking is disabled:

kernel/bpf/verifier.o:(.rodata+0x2958): undefined reference to `tc_cls_act_analyzer_ops'
kernel/bpf/verifier.o:(.rodata+0x2970): undefined reference to `xdp_analyzer_ops'

It seems that the code was written to deal with varying contents of
the arrray, but the actual #ifdef was missing. Both tc_cls_act_analyzer_ops
and xdp_analyzer_ops are defined in the core networking code, so adding
a check for CONFIG_NET seems appropriate here, and I've verified this with
many randconfig builds

Fixes: 4f9218aa ("bpf: move knowledge about post-translation offsets out of verifier")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The lan9303 driver defines eth_stp_addr as a synonym to
eth_reserved_addr_base to get the STP ethernet address 01:80:c2:00:00:00.

eth_reserved_addr_base is also used to define the start of Bridge Reserved
ethernet address range, which happen to be the STP address.

br_dev_setup refer to eth_reserved_addr_base as a definition of STP
address.

Clean up by:
 - Move the eth_stp_addr definition to linux/etherdevice.h
 - Use eth_stp_addr instead of eth_reserved_addr_base in br_dev_setup.
Signed-off-by: NEgil Hjelmeland <privat@egil-hjelmeland.no>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NFelix Manlunas <felix.manlunas@cavium.com>
Acked-by: NDerek Chickles <derek.chickles@cavium.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This tracepoint can be used to trace synack retransmits. It maintains
pointer to struct request_sock.

We cannot simply reuse trace_tcp_retransmit_skb() here, because the
sk here is the LISTEN socket. The IP addresses and ports should be
extracted from struct request_sock.

Note that, like many other tracepoints, this patch uses IS_ENABLED
in TP_fast_assign macro, which triggers sparse warning like:

./include/trace/events/tcp.h:274:1: error: directive in argument list
./include/trace/events/tcp.h:281:1: error: directive in argument list

However, there is no good solution to avoid these warnings. To the
best of our knowledge, these warnings are harmless.
Signed-off-by: NSong Liu <songliubraving@fb.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RFC 8200 (IPv6) defines Hop-by-Hop options and Destination options
extension headers. Both of these carry a list of TLVs which is
only limited by the maximum length of the extension header (2048
bytes). By the spec a host must process all the TLVs in these
options, however these could be used as a fairly obvious
denial of service attack. I think this could in fact be
a significant DOS vector on the Internet, one mitigating
factor might be that many FWs drop all packets with EH (and
obviously this is only IPv6) so an Internet wide attack might not
be so effective (yet!).

By my calculation, the worse case packet with TLVs in a standard
1500 byte MTU packet that would be processed by the stack contains
1282 invidual TLVs (including pad TLVS) or 724 two byte TLVs. I
wrote a quick test program that floods a whole bunch of these
packets to a host and sure enough there is substantial time spent
in ip6_parse_tlv. These packets contain nothing but unknown TLVS
(that are ignored), TLV padding, and bogus UDP header with zero
payload length.

  25.38%  [kernel]                    [k] __fib6_clean_all
  21.63%  [kernel]                    [k] ip6_parse_tlv
   4.21%  [kernel]                    [k] __local_bh_enable_ip
   2.18%  [kernel]                    [k] ip6_pol_route.isra.39
   1.98%  [kernel]                    [k] fib6_walk_continue
   1.88%  [kernel]                    [k] _raw_write_lock_bh
   1.65%  [kernel]                    [k] dst_release

This patch adds configurable limits to Destination and Hop-by-Hop
options. There are three limits that may be set:
  - Limit the number of options in a Hop-by-Hop or Destination options
    extension header.
  - Limit the byte length of a Hop-by-Hop or Destination options
    extension header.
  - Disallow unrecognized options in a Hop-by-Hop or Destination
    options extension header.

The limits are set in corresponding sysctls:

  ipv6.sysctl.max_dst_opts_cnt
  ipv6.sysctl.max_hbh_opts_cnt
  ipv6.sysctl.max_dst_opts_len
  ipv6.sysctl.max_hbh_opts_len

If a max_*_opts_cnt is less than zero then unknown TLVs are disallowed.
The number of known TLVs that are allowed is the absolute value of
this number.

If a limit is exceeded when processing an extension header the packet is
dropped.

Default values are set to 8 for options counts, and set to INT_MAX
for maximum length. Note the choice to limit options to 8 is an
arbitrary guess (roughly based on the fact that the stack supports
three HBH options and just one destination option).

These limits have being proposed in draft-ietf-6man-rfc6434-bis.

Tested (by Martin Lau)

I tested out 1 thread (i.e. one raw_udp process).

I changed the net.ipv6.max_dst_(opts|hbh)_number between 8 to 2048.
With sysctls setting to 2048, the softirq% is packed to 100%.
With 8, the softirq% is almost unnoticable from mpstat.

v2;
  - Code and documention cleanup.
  - Change references of RFC2460 to be RFC8200.
  - Add reference to RFC6434-bis where the limits will be in standard.
Signed-off-by: NTom Herbert <tom@quantonium.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Lipeng says:

====================
net: hns3: add support for reset

There are 4 reset types for HNS3 PF driver, include global reset,
core reset, IMP reset, PF reset.The core reset will reset all datapath
of all functions except IMP, MAC and PCI interface. Global reset is equal
with the core reset plus all MAC reset. IMP reset is caused by watchdog
timer expiration, the same range with core reset. PF reset will reset
whole physical function.

This patchset adds reset support for hns3 driver and fix some related bugs.

---
Change log:
V1 -> V2:
1, fix some comments from Yunsheng Lin.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All member of Struct hdev->hw_stats is initialized to 0 as hdev is
allocated by devm_kzalloc. But in reset process, hdev will not be
allocated again, so need clear hdev->hw_stats in reset process, otherwise
the statistic will be wrong after reset. This patch set all of the
statistic counters to zero after reset.
Signed-off-by: Nqumingguang <qumingguang@huawei.com>
Signed-off-by: NLipeng <lipeng321@huawei.com>
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>