hsr: Fix uninit-value access in hsr_get_node()

KMSAN reported the following uninit-value access issue [1]:

=====================================================
BUG: KMSAN: uninit-value in hsr_get_node+0xa2e/0xa40 net/hsr/hsr_framereg.c:246
hsr_get_node+0xa2e/0xa40 net/hsr/hsr_framereg.c:246
fill_frame_info net/hsr/hsr_forward.c:577 [inline]
hsr_forward_skb+0xe12/0x30e0 net/hsr/hsr_forward.c:615
hsr_dev_xmit+0x1a1/0x270 net/hsr/hsr_device.c:223
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline]
xmit_one net/core/dev.c:3548 [inline]
dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3564
__dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3087 [inline]
packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x735/0xa10 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
slab_alloc_node mm/slub.c:3478 [inline]
kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
__alloc_skb+0x318/0x740 net/core/skbuff.c:651
alloc_skb include/linux/skbuff.h:1286 [inline]
alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6334
sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2787
packet_alloc_skb net/packet/af_packet.c:2936 [inline]
packet_snd net/packet/af_packet.c:3030 [inline]
packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x735/0xa10 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 5033 Comm: syz-executor334 Not tainted 6.7.0-syzkaller-00562-g9f8413c4a66f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================

If the packet type ID field in the Ethernet header is either ETH_P_PRP or
ETH_P_HSR, but it is not followed by an HSR tag, hsr_get_skb_sequence_nr()
reads an invalid value as a sequence number. This causes the above issue.

This patch fixes the issue by returning NULL if the Ethernet header is not
followed by an HSR tag.

Fixes: f266a683a480 ("net/hsr: Better frame dispatch")
Reported-and-tested-by: syzbot+2ef3a8ce8e91b5a50098@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2ef3a8ce8e91b5a50098 [1]
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Link: https://lore.kernel.org/r/20240312152719.724530-1-syoshida@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: hsr: Properly parse HSRv1 supervisor frames.

While adding support for parsing the redbox supervision frames, the
author added `pull_size' and `total_pull_size' to track the amount of
bytes that were pulled from the skb during while parsing the skb so it
can be reverted/ pushed back at the end.
In the process probably copy&paste error occurred and for the HSRv1 case
the ethhdr was used instead of the hsr_tag. Later the hsr_tag was used
instead of hsr_sup_tag. The later error didn't matter because both
structs have the size so HSRv0 was still working. It broke however HSRv1
parsing because struct ethhdr is larger than struct hsr_tag.

Reinstate the old pulling flow and pull first ethhdr, hsr_tag in v1 case
followed by hsr_sup_tag.

[bigeasy: commit message]

Fixes: eafaa88b3eb7 ("net: hsr: Add support for redbox supervision frames")'
Suggested-by: Tristram.Ha@microchip.com
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: Don't log netdev_err message on unknown prp dst node

If no frames has been exchanged with a node for HSR_NODE_FORGET_TIME, the
node will be deleted from the node_db list. If a frame is sent to the node
after it is deleted, a netdev_err message for each slave interface is
produced. This should not happen with dan nodes because of supervision
frames, but can happen often with san nodes, which clutters the kernel
log. Since the hsr protocol does not support sans, this is only relevant
for the prp protocol.

Signed-off-by: Kristian Overskeid <koverskeid@gmail.com>
Link: https://lore.kernel.org/r/20230309092302.179586-1-koverskeid@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

hsr: ratelimit only when errors are printed

Recently, when automatically merging -net and net-next in MPTCP devel
tree, our CI reported [1] a conflict in hsr, the same as the one
reported by Stephen in netdev [2].

When looking at the conflict, I noticed it is in fact the v1 [3] that
has been applied in -net and the v2 [4] in net-next. Maybe the v1 was
applied by accident.

As mentioned by Jakub Kicinski [5], the new condition makes more sense
before the net_ratelimit(), not to update net_ratelimit's state which is
unnecessary if we're not going to print either way.

Here, this modification applies the v2 but in -net.

Link: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/4423171069 [1]
Link: https://lore.kernel.org/netdev/20230315100914.53fc1760@canb.auug.org.au/ [2]
Link: https://lore.kernel.org/netdev/20230307133229.127442-1-koverskeid@gmail.com/ [3]
Link: https://lore.kernel.org/netdev/20230309092302.179586-1-koverskeid@gmail.com/ [4]
Link: https://lore.kernel.org/netdev/20230308232001.2fb62013@kernel.org/ [5]
Fixes: 28e8cabe80f3 ("net: hsr: Don't log netdev_err message on unknown prp dst node")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Link: https://lore.kernel.org/r/20230315-net-20230315-hsr_framereg-ratelimit-v1-1-61d2ef176d11@tessares.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: hsr: Don't log netdev_err message on unknown prp dst node

If no frames has been exchanged with a node for HSR_NODE_FORGET_TIME, the
node will be deleted from the node_db list. If a frame is sent to the node
after it is deleted, a netdev_err message for each slave interface is
produced. This should not happen with dan nodes because of supervision
frames, but can happen often with san nodes, which clutters the kernel
log. Since the hsr protocol does not support sans, this is only relevant
for the prp protocol.

Signed-off-by: Kristian Overskeid <koverskeid@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: Use a single struct for self_node.

self_node_db is a list_head with one entry of struct hsr_node. The
purpose is to hold the two MAC addresses of the node itself.
It is convenient to recycle the structure. However having a list_head
and fetching always the first entry is not really optimal.

Created a new data strucure contaning the two MAC addresses named
hsr_self_node. Access that structure like an RCU protected pointer so
it can be replaced on the fly without blocking the reader.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

hsr: Synchronize sequence number updates.

hsr_register_frame_out() compares new sequence_nr vs the old one
recorded in hsr_node::seq_out and if the new sequence_nr is higher then
it will be written to hsr_node::seq_out as the new value.

This operation isn't locked so it is possible that two frames with the
same sequence number arrive (via the two slave devices) and are fed to
hsr_register_frame_out() at the same time. Both will pass the check and
update the sequence counter later to the same value. As a result the
content of the same packet is fed into the stack twice.

This was noticed by running ping and observing DUP being reported from
time to time.

Instead of using the hsr_priv::seqnr_lock for the whole receive path (as
it is for sending in the master node) add an additional lock that is only
used for sequence number checks and updates.

Add a per-node lock that is used during sequence number reads and
updates.

Fixes: f421436a591d3 ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

hsr: Avoid double remove of a node.

Due to the hashed-MAC optimisation one problem become visible:
hsr_handle_sup_frame() walks over the list of available nodes and merges
two node entries into one if based on the information in the supervision
both MAC addresses belong to one node. The list-walk happens on a RCU
protected list and delete operation happens under a lock.

If the supervision arrives on both slave interfaces at the same time
then this delete operation can occur simultaneously on two CPUs. The
result is the first-CPU deletes the from the list and the second CPUs
BUGs while attempting to dereference a poisoned list-entry. This happens
more likely with the optimisation because a new node for the mac_B entry
is created once a packet has been received and removed (merged) once the
supervision frame has been received.

Avoid removing/ cleaning up a hsr_node twice by adding a `removed' field
which is set to true after the removal and checked before the removal.

Fixes: f266a683a4804 ("net/hsr: Better frame dispatch")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Revert "net: hsr: use hlist_head instead of list_head for mac addresses"

The hlist optimisation (which not only uses hlist_head instead of
list_head but also splits hsr_priv::node_db into an array of 256 slots)
does not consider the "node merge":
Upon starting the hsr network (with three nodes) a packet that is
sent from node1 to node3 will also be sent from node1 to node2 and then
forwarded to node3.
As a result node3 will receive 2 packets because it is not able
to filter out the duplicate. Each packet received will create a new
struct hsr_node with macaddress_A only set the MAC address it received
from (the two MAC addesses from node1).
At some point (early in the process) two supervision frames will be
received from node1. They will be processed by hsr_handle_sup_frame()
and one frame will leave early ("Node has already been merged") and does
nothing. The other frame will be merged as portB and have its MAC
address written to macaddress_B and the hsr_node (that was created for
it as macaddress_A) will be removed.
From now on HSR is able to identify a duplicate because both packets
sent from one node will result in the same struct hsr_node because
hsr_get_node() will find the MAC address either on macaddress_A or
macaddress_B.

Things get tricky with the optimisation: If sender's MAC address is
saved as macaddress_A then the lookup will work as usual. If the MAC
address has been merged into macaddress_B of another hsr_node then the
lookup won't work because it is likely that the data structure is in
another bucket. This results in creating a new struct hsr_node and not
recognising a possible duplicate.

A way around it would be to add another hsr_node::mac_list_B and attach
it to the other bucket to ensure that this hsr_node will be looked up
either via macaddress_A _or_ macaddress_B.

I however prefer to revert it because it sounds like an academic problem
rather than real life workload plus it adds complexity. I'm not an HSR
expert with what is usual size of a network but I would guess 40 to 60
nodes. With 10.000 nodes and assuming 60us for pass-through (from node
to node) then it would take almost 600ms for a packet to almost wrap
around which sounds a lot.

Revert the hash MAC addresses optimisation.

Fixes: 4acc45db71158 ("net: hsr: use hlist_head instead of list_head for mac addresses")
Cc: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: hsr: fix hsr build error when lockdep is not enabled

In hsr, lockdep_is_held() is needed for rcu_dereference_bh_check().
But if lockdep is not enabled, lockdep_is_held() causes a build error:

ERROR: modpost: "lockdep_is_held" [net/hsr/hsr.ko] undefined!

Thus, this patch solved by adding lockdep_hsr_is_held(). This helper
function calls the lockdep_is_held() when lockdep is enabled, and returns 1
if not defined.

Fixes: e7f27420681f ("net: hsr: fix suspicious RCU usage warning in hsr_node_get_first()")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Link: https://lore.kernel.org/r/20220220153250.5285-1-claudiajkang@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: hsr: fix suspicious RCU usage warning in hsr_node_get_first()

When hsr_create_self_node() calls hsr_node_get_first(), the suspicious
RCU usage warning is occurred. The reason why this warning is raised is
the callers of hsr_node_get_first() use rcu_read_lock_bh() and
other different synchronization mechanisms. Thus, this patch solved by
replacing rcu_dereference() with rcu_dereference_bh_check().

The kernel test robot reports:
[ 50.083470][ T3596] =============================
[ 50.088648][ T3596] WARNING: suspicious RCU usage
[ 50.093785][ T3596] 5.17.0-rc3-next-20220208-syzkaller #0 Not tainted
[ 50.100669][ T3596] -----------------------------
[ 50.105513][ T3596] net/hsr/hsr_framereg.c:34 suspicious rcu_dereference_check() usage!
[ 50.113799][ T3596]
[ 50.113799][ T3596] other info that might help us debug this:
[ 50.113799][ T3596]
[ 50.124257][ T3596]
[ 50.124257][ T3596] rcu_scheduler_active = 2, debug_locks = 1
[ 50.132368][ T3596] 2 locks held by syz-executor.0/3596:
[ 50.137863][ T3596] #0: ffffffff8d3357e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3be/0xb80
[ 50.147470][ T3596] #1: ffff88807ec9d5f0 (&hsr->list_lock){+...}-{2:2}, at: hsr_create_self_node+0x225/0x650
[ 50.157623][ T3596]
[ 50.157623][ T3596] stack backtrace:
[ 50.163510][ T3596] CPU: 1 PID: 3596 Comm: syz-executor.0 Not tainted 5.17.0-rc3-next-20220208-syzkaller #0
[ 50.173381][ T3596] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 50.183623][ T3596] Call Trace:
[ 50.186904][ T3596] <TASK>
[ 50.189844][ T3596] dump_stack_lvl+0xcd/0x134
[ 50.194640][ T3596] hsr_node_get_first+0x9b/0xb0
[ 50.199499][ T3596] hsr_create_self_node+0x22d/0x650
[ 50.204688][ T3596] hsr_dev_finalize+0x2c1/0x7d0
[ 50.209669][ T3596] hsr_newlink+0x315/0x730
[ 50.214113][ T3596] ? hsr_dellink+0x130/0x130
[ 50.218789][ T3596] ? rtnl_create_link+0x7e8/0xc00
[ 50.223803][ T3596] ? hsr_dellink+0x130/0x130
[ 50.228397][ T3596] __rtnl_newlink+0x107c/0x1760
[ 50.233249][ T3596] ? rtnl_setlink+0x3c0/0x3c0
[ 50.238043][ T3596] ? is_bpf_text_address+0x77/0x170
[ 50.243362][ T3596] ? lock_downgrade+0x6e0/0x6e0
[ 50.248219][ T3596] ? unwind_next_frame+0xee1/0x1ce0
[ 50.253605][ T3596] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 50.259669][ T3596] ? __sanitizer_cov_trace_cmp4+0x1c/0x70
[ 50.265423][ T3596] ? is_bpf_text_address+0x99/0x170
[ 50.270819][ T3596] ? kernel_text_address+0x39/0x80
[ 50.275950][ T3596] ? __kernel_text_address+0x9/0x30
[ 50.281336][ T3596] ? unwind_get_return_address+0x51/0x90
[ 50.286975][ T3596] ? create_prof_cpu_mask+0x20/0x20
[ 50.292178][ T3596] ? arch_stack_walk+0x93/0xe0
[ 50.297172][ T3596] ? kmem_cache_alloc_trace+0x42/0x2c0
[ 50.302637][ T3596] ? rcu_read_lock_sched_held+0x3a/0x70
[ 50.308194][ T3596] rtnl_newlink+0x64/0xa0
[ 50.312524][ T3596] ? __rtnl_newlink+0x1760/0x1760
[ 50.317545][ T3596] rtnetlink_rcv_msg+0x413/0xb80
[ 50.322631][ T3596] ? rtnl_newlink+0xa0/0xa0
[ 50.327159][ T3596] netlink_rcv_skb+0x153/0x420
[ 50.331931][ T3596] ? rtnl_newlink+0xa0/0xa0
[ 50.336436][ T3596] ? netlink_ack+0xa80/0xa80
[ 50.341095][ T3596] ? netlink_deliver_tap+0x1a2/0xc40
[ 50.346532][ T3596] ? netlink_deliver_tap+0x1b1/0xc40
[ 50.351839][ T3596] netlink_unicast+0x539/0x7e0
[ 50.356633][ T3596] ? netlink_attachskb+0x880/0x880
[ 50.361750][ T3596] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70
[ 50.368003][ T3596] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70
[ 50.374707][ T3596] ? __phys_addr_symbol+0x2c/0x70
[ 50.379753][ T3596] ? __sanitizer_cov_trace_cmp8+0x1d/0x70
[ 50.385568][ T3596] ? __check_object_size+0x16c/0x4f0
[ 50.390859][ T3596] netlink_sendmsg+0x904/0xe00
[ 50.395715][ T3596] ? netlink_unicast+0x7e0/0x7e0
[ 50.400722][ T3596] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70
[ 50.407003][ T3596] ? netlink_unicast+0x7e0/0x7e0
[ 50.412119][ T3596] sock_sendmsg+0xcf/0x120
[ 50.416548][ T3596] __sys_sendto+0x21c/0x320
[ 50.421052][ T3596] ? __ia32_sys_getpeername+0xb0/0xb0
[ 50.426427][ T3596] ? lockdep_hardirqs_on_prepare+0x400/0x400
[ 50.432721][ T3596] ? __context_tracking_exit+0xb8/0xe0
[ 50.438188][ T3596] ? lock_downgrade+0x6e0/0x6e0
[ 50.443041][ T3596] ? lock_downgrade+0x6e0/0x6e0
[ 50.447902][ T3596] __x64_sys_sendto+0xdd/0x1b0
[ 50.452759][ T3596] ? lockdep_hardirqs_on+0x79/0x100
[ 50.457964][ T3596] ? syscall_enter_from_user_mode+0x21/0x70
[ 50.464150][ T3596] do_syscall_64+0x35/0xb0
[ 50.468565][ T3596] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 50.474452][ T3596] RIP: 0033:0x7f3148504e1c
[ 50.479052][ T3596] Code: fa fa ff ff 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 20 fb ff ff 48 8b
[ 50.498926][ T3596] RSP: 002b:00007ffeab5f2ab0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
[ 50.507342][ T3596] RAX: ffffffffffffffda RBX: 00007f314959d320 RCX: 00007f3148504e1c
[ 50.515393][ T3596] RDX: 0000000000000048 RSI: 00007f314959d370 RDI: 0000000000000003
[ 50.523444][ T3596] RBP: 0000000000000000 R08: 00007ffeab5f2b04 R09: 000000000000000c
[ 50.531492][ T3596] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
[ 50.539455][ T3596] R13: 00007f314959d370 R14: 0000000000000003 R15: 0000000000000000

Fixes: 4acc45db7115 ("net: hsr: use hlist_head instead of list_head for mac addresses")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-and-tested-by: syzbot+f0eb4f3876de066b128c@syzkaller.appspotmail.com
Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: use hlist_head instead of list_head for mac addresses

Currently, HSR manages mac addresses of known HSR nodes by using list_head.
It takes a lot of time when there are a lot of registered nodes due to
finding specific mac address nodes by using linear search. We can be
reducing the time by using hlist. Thus, this patch moves list_head to
hlist_head for mac addresses and this allows for further improvement of
network performance.

Condition: registered 10,000 known HSR nodes
Before:
# iperf3 -c 192.168.10.1 -i 1 -t 10
Connecting to host 192.168.10.1, port 5201
[ 5] local 192.168.10.2 port 59442 connected to 192.168.10.1 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.49 sec 3.75 MBytes 21.1 Mbits/sec 0 158 KBytes
[ 5] 1.49-2.05 sec 1.25 MBytes 18.7 Mbits/sec 0 166 KBytes
[ 5] 2.05-3.06 sec 2.44 MBytes 20.3 Mbits/sec 56 16.9 KBytes
[ 5] 3.06-4.08 sec 1.43 MBytes 11.7 Mbits/sec 11 38.0 KBytes
[ 5] 4.08-5.00 sec 951 KBytes 8.49 Mbits/sec 0 56.3 KBytes

After:
# iperf3 -c 192.168.10.1 -i 1 -t 10
Connecting to host 192.168.10.1, port 5201
[ 5] local 192.168.10.2 port 36460 connected to 192.168.10.1 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 7.39 MBytes 62.0 Mbits/sec 3 130 KBytes
[ 5] 1.00-2.00 sec 5.06 MBytes 42.4 Mbits/sec 16 113 KBytes
[ 5] 2.00-3.00 sec 8.58 MBytes 72.0 Mbits/sec 42 94.3 KBytes
[ 5] 3.00-4.00 sec 7.44 MBytes 62.4 Mbits/sec 2 131 KBytes
[ 5] 4.00-5.07 sec 8.13 MBytes 63.5 Mbits/sec 38 92.9 KBytes

Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: Add support for redbox supervision frames

added support for the redbox supervision frames
as defined in the IEC-62439-3:2018.

Signed-off-by: Andreas Oetken <andreas.oetken@siemens-energy.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: get ready for const netdev->dev_addr

hsr_create_self_node() may get netdev->dev_addr
passed as argument, netdev->dev_addr will be
const soon.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: don't check sequence number if tag removal is offloaded

Don't check the sequence number when deciding when to update time_in in
the node table if tag removal is offloaded since the sequence number is
part of the tag. This fixes a problem where the times in the node table
wouldn't update when 0 appeared to be before or equal to seq_out when
tag removal was offloaded.

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: add support for EntryForgetTime

In IEC 62439-3 EntryForgetTime is defined with a value of 400 ms. When a
node does not send any frame within this time, the sequence number check
for can be ignored. This solves communication issues with Cisco IE 2000
in Redbox mode.

Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Marco Wenzel <marco.wenzel@a-eberle.de>
Reviewed-by: George McCollister <george.mccollister@gmail.com>
Tested-by: George McCollister <george.mccollister@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210224094653.1440-1-marco.wenzel@a-eberle.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: hsr: add offloading support

Add support for offloading of HSR/PRP (IEC 62439-3) tag insertion
tag removal, duplicate generation and forwarding.

For HSR, insertion involves the switch adding a 6 byte HSR header after
the 14 byte Ethernet header. For PRP it adds a 6 byte trailer.

Tag removal involves automatically stripping the HSR/PRP header/trailer
in the switch. This is possible when the switch also performs auto
deduplication using the HSR/PRP header/trailer (making it no longer
required).

Forwarding involves automatically forwarding between redundant ports in
an HSR. This is crucial because delay is accumulated as a frame passes
through each node in the ring.

Duplication involves the switch automatically sending a single frame
from the CPU port to both redundant ports. This is required because the
inserted HSR/PRP header/trailer must contain the same sequence number
on the frames sent out both redundant ports.

Export is_hsr_master so DSA can tell them apart from other devices in
dsa_slave_changeupper.

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: prp: add packet handling support

DAN-P (Dual Attached Nodes PRP) nodes are expected to receive
traditional IP packets as well as PRP (Parallel Redundancy
Protocol) tagged (trailer) packets. PRP trailer is 6 bytes
of PRP protocol unit called RCT, Redundancy Control Trailer
(RCT) similar to HSR tag. PRP network can have traditional
devices such as bridges/switches or PC attached to it and
should be able to communicate. Regular Ethernet devices treat
the RCT as pads. This patch adds logic to format L2 frames
from network stack to add a trailer (RCT) and send it as
duplicates over the slave interfaces when the protocol is
PRP as per IEC 62439-3. At the ingress, it strips the trailer,
do duplicate detection and rejection and forward a stripped
frame up the network stack. PRP device should accept frames
from Singly Attached Nodes (SAN) and thus the driver mark
the link where the frame came from in the node table.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: enhance netlink socket interface to support PRP

Parallel Redundancy Protocol (PRP) is another redundancy protocol
introduced by IEC 63439 standard. It is similar to HSR in many
aspects:-

- Use a pair of Ethernet interfaces to created the PRP device
- Use a 6 byte redundancy protocol part (RCT, Redundancy Check
Trailer) similar to HSR Tag.
- Has Link Redundancy Entity (LRE) that works with RCT to implement
redundancy.

Key difference is that the protocol unit is a trailer instead of a
prefix as in HSR. That makes it inter-operable with tradition network
components such as bridges/switches which treat it as pad bytes,
whereas HSR nodes requires some kind of translators (Called redbox) to
talk to regular network devices. This features allows regular linux box
to be converted to a DAN-P box. DAN-P stands for Dual Attached Node - PRP
similar to DAN-H (Dual Attached Node - HSR).

Add a comment at the header/source code to explicitly state that the
driver files also handles PRP protocol as well.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: validate address B before copying to skb

Validate MAC address before copying the same to outgoing frame
skb destination address. Since a node can have zero mac
address for Link B until a valid frame is received over
that link, this fix address the issue of a zero MAC address
being in the packet.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: use rcu_read_lock() in hsr_get_node_{list/status}()

hsr_get_node_{list/status}() are not under rtnl_lock() because
they are callback functions of generic netlink.
But they use __dev_get_by_index() without rtnl_lock().
So, it would use unsafe data.
In order to fix it, rcu_read_lock() and dev_get_by_index_rcu()
are used instead of __dev_get_by_index().

Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: use netdev_err() instead of WARN_ONCE()

When HSR interface is sending a frame, it finds a node with
the destination ethernet address from the list.
If there is no node, it calls WARN_ONCE().
But, using WARN_ONCE() for this situation is a little bit overdoing.
So, in this patch, the netdev_err() is used instead.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: Pass lockdep expression to RCU lists

node_db is traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of hsr->list_lock.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.

Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: remove seq_nr_after_or_eq

It's never used after introduced. So maybe better to remove.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Arvid Brodin <arvid.brodin@alten.se>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: fix a race condition in node list insertion and deletion

hsr nodes are protected by RCU and there is no write side lock.
But node insertions and deletions could be being operated concurrently.
So write side locking is needed.

Test commands:
ip netns add nst
ip link add veth0 type veth peer name veth1
ip link add veth2 type veth peer name veth3
ip link set veth1 netns nst
ip link set veth3 netns nst
ip link set veth0 up
ip link set veth2 up
ip link add hsr0 type hsr slave1 veth0 slave2 veth2
ip a a 192.168.100.1/24 dev hsr0
ip link set hsr0 up
ip netns exec nst ip link set veth1 up
ip netns exec nst ip link set veth3 up
ip netns exec nst ip link add hsr1 type hsr slave1 veth1 slave2 veth3
ip netns exec nst ip a a 192.168.100.2/24 dev hsr1
ip netns exec nst ip link set hsr1 up

for i in {0..9}
do
for j in {0..9}
do
for k in {0..9}
do
for l in {0..9}
do
arping 192.168.100.2 -I hsr0 -s 00:01:3$i:4$j:5$k:6$l -c1 &
done
done
done
done

Splat looks like:
[ 236.066091][ T3286] list_add corruption. next->prev should be prev (ffff8880a5940300), but was ffff8880a5940d0.
[ 236.069617][ T3286] ------------[ cut here ]------------
[ 236.070545][ T3286] kernel BUG at lib/list_debug.c:25!
[ 236.071391][ T3286] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 236.072343][ T3286] CPU: 0 PID: 3286 Comm: arping Tainted: G W 5.5.0-rc1+ #209
[ 236.073463][ T3286] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 236.074695][ T3286] RIP: 0010:__list_add_valid+0x74/0xd0
[ 236.075499][ T3286] Code: 48 39 da 75 27 48 39 f5 74 36 48 39 dd 74 31 48 83 c4 08 b8 01 00 00 00 5b 5d c3 48 b
[ 236.078277][ T3286] RSP: 0018:ffff8880aaa97648 EFLAGS: 00010286
[ 236.086991][ T3286] RAX: 0000000000000075 RBX: ffff8880d4624c20 RCX: 0000000000000000
[ 236.088000][ T3286] RDX: 0000000000000075 RSI: 0000000000000008 RDI: ffffed1015552ebf
[ 236.098897][ T3286] RBP: ffff88809b53d200 R08: ffffed101b3c04f9 R09: ffffed101b3c04f9
[ 236.099960][ T3286] R10: 00000000308769a1 R11: ffffed101b3c04f8 R12: ffff8880d4624c28
[ 236.100974][ T3286] R13: ffff8880d4624c20 R14: 0000000040310100 R15: ffff8880ce17ee02
[ 236.138967][ T3286] FS: 00007f23479fa680(0000) GS:ffff8880d9c00000(0000) knlGS:0000000000000000
[ 236.144852][ T3286] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 236.145720][ T3286] CR2: 00007f4a14bab210 CR3: 00000000a61c6001 CR4: 00000000000606f0
[ 236.146776][ T3286] Call Trace:
[ 236.147222][ T3286] hsr_add_node+0x314/0x490 [hsr]
[ 236.153633][ T3286] hsr_forward_skb+0x2b6/0x1bc0 [hsr]
[ 236.154362][ T3286] ? rcu_read_lock_sched_held+0x90/0xc0
[ 236.155091][ T3286] ? rcu_read_lock_bh_held+0xa0/0xa0
[ 236.156607][ T3286] hsr_dev_xmit+0x70/0xd0 [hsr]
[ 236.157254][ T3286] dev_hard_start_xmit+0x160/0x740
[ 236.157941][ T3286] __dev_queue_xmit+0x1961/0x2e10
[ 236.158565][ T3286] ? netdev_core_pick_tx+0x2e0/0x2e0
[ ... ]

Reported-by: syzbot+3924327f9ad5f4d2b343@syzkaller.appspotmail.com
Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: implement dellink to clean up resources

hsr_link_ops implements ->newlink() but not ->dellink(),
which leads that resources not released after removing the device,
particularly the entries in self_node_db and node_db.

So add ->dellink() implementation to replace the priv_destructor.
This also makes the code slightly easier to understand.

Reported-by: syzbot+c6167ec3de7def23d1e8@syzkaller.appspotmail.com
Cc: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: fix don't prune the master node from the node_db

Don't prune the master node in the hsr_prune_nodes function.
Neither time_in[HSR_PT_SLAVE_A] nor time_in[HSR_PT_SLAVE_B]
will ever be updated by hsr_register_frame_in for the master port.
Thus, the master node will be repeatedly pruned leading to
repeated packet loss.
This bug never appeared because the hsr_prune_nodes function
was only called once. Since commit 5150b45fd355
("net: hsr: Fix node prune function for forget time expiry") this issue
is fixed unveiling the issue described above.

Fixes: 5150b45fd355 ("net: hsr: Fix node prune function for forget time expiry")
Signed-off-by: Andreas Oetken <andreas.oetken@siemens.com>
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: Fix node prune function for forget time expiry

HSR should forget nodes after configured node forget time expiry based
on HSR_NODE_FORGET_TIME. As part of hsr_prune_nodes(), code checks to
see if entries are to be flushed out if not heard for longer than forget
time. But currently hsr_prune_nodes() is called only once during device
creation. Restart the timer at the end of hsr_prune_nodes() so that
hsr_prune_nodes() gets called periodically and forgotten entries are
removed from node table.

Signed-off-by: Aaron Kramer <a-kramer@ti.com>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: add debugfs support for display node list

This adds a debugfs interface to allow display the nodes learned
by the hsr master.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: convert to SPDX identifier

Use SPDX-License-Identifier instead of a verbose license text.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: add blank line after function declaration

Add a blank line after function declaration as suggested by
checkpatch.pl -f

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: remove camel case usage in the code

Current driver code uses camel case in many places. This is
seen when ran checkpatch.pl -f on files under net/hsr. This
patch fixes the code to remove camel case usage.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: add missing space around operator in code

This patch add missing space around operator in code. This is
seen when ran checkpatch.pl -f on files under net/hsr.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: fix placement of logical operator in a multi-line statement

In a multi-line statement exceeding 80 characters, logical operator
should be at the end of a line instead of being at the start. This
is seen when ran checkpatch.pl -f on files under net/hsr. The change
is per suggestion from checkpatch.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: remove unnecessary space after a cast

This patch removes unnecessary space after a cast. This is seen
when ran checkpatch.pl -f on files under net/hsr.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: fix NULL checks in the code

This patch replaces all instance of NULL checks such as
if (foo == NULL) with if (!foo)
Also
if (foo != NULL) with if (foo)

This is seen when ran checkpatch.pl -f on files under net/hsr
and suggestion is to replace as above.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: fix alignment issues in the code for functions

This patch fixes alignment issues in code for functions. This is
seen when ran checkpatch.pl -f option on files under net/hsr.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: fix multiple blank lines in the code

This patch fixes multiple blank lines in the code. This is seen
when ran checkpatch.pl -f option for files under net/hsr

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: fix lines exceeding 80 characters

This patch fixes lines exceeding 80 characters. This is seen
when ran checkpatch.pl with -f option for files under
net/hsr.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: fix memory leak in hsr_dev_finalize()

If hsr_add_port(hsr, hsr_dev, HSR_PT_MASTER) failed to
add port, it directly returns res and forgets to free the node
that allocated in hsr_create_self_node(), and forgets to delete
the node->mac_list linked in hsr->self_node_db.

BUG: memory leak
unreferenced object 0xffff8881cfa0c780 (size 64):
comm "syz-executor.0", pid 2077, jiffies 4294717969 (age 2415.377s)
hex dump (first 32 bytes):
e0 c7 a0 cf 81 88 ff ff 00 02 00 00 00 00 ad de ................
00 e6 49 cd 81 88 ff ff c0 9b 87 d0 81 88 ff ff ..I.............
backtrace:
[<00000000e2ff5070>] hsr_dev_finalize+0x736/0x960 [hsr]
[<000000003ed2e597>] hsr_newlink+0x2b2/0x3e0 [hsr]
[<000000003fa8c6b6>] __rtnl_newlink+0xf1f/0x1600 net/core/rtnetlink.c:3182
[<000000001247a7ad>] rtnl_newlink+0x66/0x90 net/core/rtnetlink.c:3240
[<00000000e7d1b61d>] rtnetlink_rcv_msg+0x54e/0xb90 net/core/rtnetlink.c:5130
[<000000005556bd3a>] netlink_rcv_skb+0x129/0x340 net/netlink/af_netlink.c:2477
[<00000000741d5ee6>] netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
[<00000000741d5ee6>] netlink_unicast+0x49a/0x650 net/netlink/af_netlink.c:1336
[<000000009d56f9b7>] netlink_sendmsg+0x88b/0xdf0 net/netlink/af_netlink.c:1917
[<0000000046b35c59>] sock_sendmsg_nosec net/socket.c:621 [inline]
[<0000000046b35c59>] sock_sendmsg+0xc3/0x100 net/socket.c:631
[<00000000d208adc9>] __sys_sendto+0x33e/0x560 net/socket.c:1786
[<00000000b582837a>] __do_sys_sendto net/socket.c:1798 [inline]
[<00000000b582837a>] __se_sys_sendto net/socket.c:1794 [inline]
[<00000000b582837a>] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:1794
[<00000000c866801d>] do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290
[<00000000fea382d9>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[<00000000e01dacb3>] 0xffffffffffffffff

Fixes: c5a759117210 ("net/hsr: Use list_head (and rcu) instead of array for slave devices.")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: hsr: Convert timers to use timer_setup()

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: Arvid Brodin <arvid.brodin@alten.se>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: fix incorrect warning

When HSR interface is setup using ip link command, an annoying warning
appears with the trace as below:-

[ 203.019828] hsr_get_node: Non-HSR frame
[ 203.019833] Modules linked in:
[ 203.019848] CPU: 0 PID: 158 Comm: sd-resolve Tainted: G W 4.12.0-rc3-00052-g9fa6bf70 #2
[ 203.019853] Hardware name: Generic DRA74X (Flattened Device Tree)
[ 203.019869] [<c0110280>] (unwind_backtrace) from [<c010c2f4>] (show_stack+0x10/0x14)
[ 203.019880] [<c010c2f4>] (show_stack) from [<c04b9f64>] (dump_stack+0xac/0xe0)
[ 203.019894] [<c04b9f64>] (dump_stack) from [<c01374e8>] (__warn+0xd8/0x104)
[ 203.019907] [<c01374e8>] (__warn) from [<c0137548>] (warn_slowpath_fmt+0x34/0x44)
root@am57xx-evm:~# [ 203.019921] [<c0137548>] (warn_slowpath_fmt) from [<c081126c>] (hsr_get_node+0x148/0x170)
[ 203.019932] [<c081126c>] (hsr_get_node) from [<c0814240>] (hsr_forward_skb+0x110/0x7c0)
[ 203.019942] [<c0814240>] (hsr_forward_skb) from [<c0811d64>] (hsr_dev_xmit+0x2c/0x34)
[ 203.019954] [<c0811d64>] (hsr_dev_xmit) from [<c06c0828>] (dev_hard_start_xmit+0xc4/0x3bc)
[ 203.019963] [<c06c0828>] (dev_hard_start_xmit) from [<c06c13d8>] (__dev_queue_xmit+0x7c4/0x98c)
[ 203.019974] [<c06c13d8>] (__dev_queue_xmit) from [<c0782f54>] (ip6_finish_output2+0x330/0xc1c)
[ 203.019983] [<c0782f54>] (ip6_finish_output2) from [<c0788f0c>] (ip6_output+0x58/0x454)
[ 203.019994] [<c0788f0c>] (ip6_output) from [<c07b16cc>] (mld_sendpack+0x420/0x744)

As this is an expected path to hsr_get_node() with frame coming from
the master interface, add a check to ensure packet is not from the
master port and then warn.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Added support for HSR v1

This patch adds support for the newer version 1 of the HSR
networking standard. Version 0 is still default and the new
version has to be selected via iproute2.

Main changes are in the supervision frame handling and its
ethertype field.

Signed-off-by: Peter Heise <peter.heise@airbus.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Remove left-over never-true conditional code.

MacAddressB is an array (unsigned char MacAddressB[ETH_ALEN]) and is allocated
as a part of *node_dst (which is a struct hsr_node). So the condition is always
false.

Detected by Dan Carpenter.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Better frame dispatch

This patch removes the separate paths for frames coming from the outside, and
frames sent from the HSR device, and instead makes all frames go through
hsr_forward_skb() in hsr_forward.c. This greatly improves code readability and
also opens up the possibility for future support of the HSR Interlink device
that is the basis for HSR RedBoxes and HSR QuadBoxes, as well as VLAN
compatibility.

Other improvements:
* A reduction in the number of times an skb is copied on machines without
HAVE_EFFICIENT_UNALIGNED_ACCESS, which improves throughput somewhat.
* Headers are now created using the standard eth_header(), and using the
standard hard_header_len.
* Each HSR slave now gets its own private skb, so slave-specific fields can be
correctly set.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Use list_head (and rcu) instead of array for slave devices.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Move slave init to hsr_slave.c.

Also try to prevent some possible slave dereference race conditions. This is
finalized in the next patch, which abandons the slave array in favour of
a list_head list and list RCU.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Move to per-hsr device prune timer.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Better variable names and update of contact info.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: off by one sanity check in hsr_register_frame_in()

This is a sanity check and we never pass invalid values so this patch
doesn't change anything. However the node->time_in[] array has
HSR_MAX_SLAVE (2) elements and not HSR_MAX_DEV (3).

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hsr: Use ether_addr_copy

It's slightly smaller/faster for some architectures.
Make sure def_multicast_addr is __aligned(2)

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: using kfree_rcu() to simplify the code

The callback function of call_rcu() just calls a kfree(), so we
can use kfree_rcu() instead of call_rcu() + callback function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Very small fix of comment style.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)

High-availability Seamless Redundancy ("HSR") provides instant failover
redundancy for Ethernet networks. It requires a special network topology where
all nodes are connected in a ring (each node having two physical network
interfaces). It is suited for applications that demand high availability and
very short reaction time.

HSR acts on the Ethernet layer, using a registered Ethernet protocol type to
send special HSR frames in both directions over the ring. The driver creates
virtual network interfaces that can be used just like any ordinary Linux
network interface, for IP/TCP/UDP traffic etc. All nodes in the network ring
must be HSR capable.

This code is a "best effort" to comply with the HSR standard as described in
IEC 62439-3:2010 (HSRv0).

Signed-off-by: Arvid Brodin <arvid.brodin@xdin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>