Yangbo Lu says:

====================
ptp_qoriq: support FIPER3

The FIPER3 (fixed interval period pulse generator) is supported on
DPAA2 and ENETC network controller hardware. This patch-set is to
support it in ptp_qoriq driver and dt-binding.

Changes for v2:
- Some improvement in code.
- Added ACK from Vladimir.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The FIPER3 (fixed interval period pulse generator) is supported on
DPAA2 and ENETC network controller hardware. This patch is to support
it in ptp_qoriq driver.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add fsl,tmr-fiper3 property definition which is supported only
on DPAA2 and ENETC network controller hardware.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Alex Elder says:

====================
net: ipa: wake up system on RX available

This series arranges for the IPA driver to wake up a suspended
system if the IPA hardware has a packet to deliver to the AP.

Version 2 replaced the first patch from version 1 with three
patches, in response to David Miller's feedback.  And based on
Bjorn Andersson's feedback on version 2, this version reworks
the tracking of IPA clock references.  As a result, we no
longer need a flag to determine whether a "don't' suspend" clock
reference is held (though an bit in a bitmask is still used for
a different purpose).

In summary:
    - A refcount_t is used to track IPA clock references where an
      atomic_t was previously used.  (This may go away soon as well,
      with upcoming work to implement runtime PM.)
    - We no longer track whether a special reference has been taken
      to avoid suspending IPA.
    - A bit in a bitmask is used to ensure we only trigger a system
      resume once per system suspend.
And from the original series:
    - Suspending endpoints only occurs when suspending the driver,
      not when dropping the last clock reference.  Resuming
      endpoints is also disconnected from starting the clock.
    - The IPA SUSPEND interrupt is now a wakeup interrupt.  If it
      fires, it schedules a system resume operation.
    - The GSI interrupt is no longer a wakeup interrupt.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

We now trigger a system resume when we receive an IPA SUSPEND
interrupt.  We should *not* wake up on GSI interrupts.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Now that we handle wakeup interrupts properly, arrange for the IPA
interrupt to be treated as a wakeup interrupt.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The previous patch causes a system resume to be triggered when a
packet is available for receipt on a suspended RX endpoint.

The CLOCK_HELD flag was previously used to indicate that an extra
clock reference was held, preventing suspend.  But we no longer need
such a flag:
  - We take an initial reference in ipa_config().
  - That reference is held until ipa_suspend() releases it.
  - A subsequent system resume leads to a reference getting
    re-acquired in ipa_resume().
  - This can repeat until ultimately the module is removed, where
    ipa_remove() releases the reference.
We no longer need a special flag to determine whether this extra
reference is held--it is, provided probe has completed successfully
and the driver is not suspended (or removed).

On the other hand, once suspended, it's possible for more than one
endpoint to trip the IPA SUSPEND interrupt, and we only want to
trigger the system resume once.  So repurpose the Boolean CLOCK_HELD
flag to record whether the IPA SUSPEND handler should initiate a
system resume.

The flag will be be cleared each time ipa_suspend() is called,
*before* any endpoints are suspended.  And it will be set inside the
IPA SUSPEND interrupt handler exactly once per suspend.

Rename the flag IPA_FLAG_RESUMED to reflect its new purpose.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The call to wakeup_source_register() in ipa_probe() does not do what
it was intended to do.  Call device_init_wakeup() in ipa_setup()
instead, to set the IPA device as wakeup-capable and to initially
enable wakeup capability.

When we receive a SUSPEND interrupt, call pm_wakeup_dev_event()
with a zero processing time, to simply call for a resume without
any other processing.  The ipa_resume() call will take care of
waking things up again, and will handle receiving the packet.

Note that this gets rid of a clock reference counting bug that
occurred when handling an IPA SUSPEND interrupt.  Specifically,
ipa_suspend_handler() took an IPA clock reference *in addition*
to the one taken by ipa_resume().  There is no need to back-port
this fix however, because it only affects code that was not
previously working (this patch is part of fixing that).
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently, when (before) the last IPA clock reference is dropped,
all endpoints are suspended.  And whenever the first IPA clock
reference is taken, all endpoints are resumed (or started).

In most cases there's no need to start endpoints when the clock
starts.  So move the calls to ipa_endpoint_suspend() and
ipa_endpoint_resume() out of ipa_clock_put() and ipa_clock_get(),
respectiely.  Instead, only suspend endpoints when handling a system
suspend, and only resume endpoints when handling a system resume.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

We take a clock reference in ipa_config() in order to prevent the
the IPA clock from being shutdown until a power management suspend
request arrives.  An atomic field in the IPA structure records
whether that extra reference had been taken.

Rather than using an atomic to represent a Boolean value, define
a new flags bitmap, and define a "clock held" flag to represent
whether the extra clock reference has been taken.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Take advantage of the checking provided by refcount_t, rather than
using a plain atomic to represent the IPA clock reference count.

Note that we need to *set* the value to 1 in ipa_clock_get() rather
than incrementing it from 0 (because doing that is considered an
error for a refcount_t).
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The internal Gigabit PHY on Broadcom STB chips has a digital clock which
drives its MDIO interface among other things, the driver now requests
and manage that clock during .probe() and .remove() accordingly.

Because the PHY driver can be probed with the clocks turned off we need
to apply the dummy BMSR workaround during the driver probe function to
ensure subsequent MDIO read or write towards the PHY will succeed.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the header file containing a function's prototype isn't included by
the sourcefile containing the associated function, the build system
complains of missing prototypes.

Fixes the following W=1 kernel build warning(s):

net/tipc/udp_media.c:446:5: warning: no previous prototype for ‘tipc_udp_nl_dump_remoteip’ [-Wmissing-prototypes]
net/tipc/udp_media.c:532:5: warning: no previous prototype for ‘tipc_udp_nl_add_bearer_data’ [-Wmissing-prototypes]
net/tipc/udp_media.c:614:5: warning: no previous prototype for ‘tipc_udp_nl_bearer_add’ [-Wmissing-prototypes]
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

It is no used any more, so can remove it.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the header file containing a function's prototype isn't included by
the sourcefile containing the associated function, the build system
complains of missing prototypes.

Fixes the following W=1 kernel build warning(s):

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_dcb.c:453:6: warning: no previous prototype for ‘hclge_dcb_ops_set’ [-Wmissing-prototypes]
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the header file containing a function's prototype isn't included by
the sourcefile containing the associated function, the build system
complains of missing prototypes.

Fixes the following W=1 kernel build warning(s):

drivers/net/appletalk/cops.c:213:28: warning: no previous prototype for ‘cops_probe’ [-Wmissing-prototypes]
drivers/net/appletalk/ltpc.c:1014:28: warning: no previous prototype for ‘ltpc_probe’ [-Wmissing-prototypes]
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the header file containing a function's prototype isn't included by
the sourcefile containing the associated function, the build system
complains of missing prototypes.

Fixes the following W=1 kernel build warning(s):

drivers/net/ethernet/cavium/liquidio/cn68xx_device.c:124:5: warning: no previous prototype for ‘lio_setup_cn68xx_octeon_device’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:159:1: warning: no previous prototype for ‘octeon_pci_read_core_mem’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:168:1: warning: no previous prototype for ‘octeon_pci_write_core_mem’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:176:5: warning: no previous prototype for ‘octeon_read_device_mem64’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:185:5: warning: no previous prototype for ‘octeon_read_device_mem32’ [-Wmissing-prototypes]
drivers/net/ethernet/cavium/liquidio/octeon_mem_ops.c:194:6: warning: no previous prototype for ‘octeon_write_device_mem32’ [-Wmissing-prototypes]
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Historically L2TP core statistics count the L2TP header in the
per-session and per-tunnel byte counts tracked for transmission and
receipt.

Now that l2tp_xmit_skb updates tx stats, it is necessary for
l2tp_xmit_core to pass out the length of the transmitted packet so that
the statistics can be updated correctly.
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make a distinction between different irqs by netdev name or pci name.
Signed-off-by: Luo bin <luobin9@huawei.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/ethernet/cortina/gemini.c: In function gmac_get_ringparam:
drivers/net/ethernet/cortina/gemini.c:2125:21: warning: variable ‘config0’ set but not used [-Wunused-but-set-variable]

drivers/net/ethernet/cortina/gemini.c: In function gmac_init:
drivers/net/ethernet/cortina/gemini.c:512:6: warning: variable ‘val’ set but not used [-Wunused-but-set-variable]

these variable is never used, so remove it.
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Yangbo Lu says:

====================
dpaa2_eth: support 1588 one-step timestamping

This patch-set is to add MC APIs of 1588 one-step timestamping, and
support one-step timestamping for PTP Sync packet on DPAA2.

Before egress, one-step timestamping enablement needs,

- Enabling timestamp and FAS (Frame Annotation Status) in
  dpni buffer layout.

- Write timestamp to frame annotation and set PTP bit in
  FAS to mark as one-step timestamping event.

- Enabling one-step timestamping by dpni_set_single_step_cfg()
  API, with offset provided to insert correction time on frame.
  The offset must respect all MAC headers, VLAN tags and other
  protocol headers accordingly. The correction field update can
  consider delays up to one second. So PTP frame needs to be
  filtered and parsed, and written timestamp into Sync frame
  originTimestamp field.

The operation of API dpni_set_single_step_cfg() has to be done
when no one-step timestamping frames are in flight. So we have
to make sure the last one-step timestamping frame has already
been transmitted on hardware before starting to send the current
one. The resolution is,

- Utilize skb->cb[0] to mark timestamping request per packet.
  If it is one-step timestamping PTP sync packet, queue to skb queue.
  If not, transmit immediately.

- Schedule a work to transmit skbs in skb queue.

- mutex lock is used to ensure the last one-step timestamping packet
  has already been transmitted on hardware through TX confirmation queue
  before transmitting current packet.

Changes for v2:
	- Removed unused variable priv in dpaa2_eth_xdp_create_fd().
Changes for v3:
	- Fixed sparse warnings.
	- Fix build issue on 32-bit.
	- Converted to use ptp_parse_header.
Changes for v4:
	- Used WARN_ONCE instead of netdev_err in data path.
	- Enabled timestamping only when PTP driver is ready.
	- Added comments in using onestep_tstamp_lock.
	- Dropped dpmac.c sparse warning fix-up patch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch is to add PTP sync packet one-step timestamping support.
Before egress, one-step timestamping enablement needs,

- Enabling timestamp and FAS (Frame Annotation Status) in
  dpni buffer layout.

- Write timestamp to frame annotation and set PTP bit in
  FAS to mark as one-step timestamping event.

- Enabling one-step timestamping by dpni_set_single_step_cfg()
  API, with offset provided to insert correction time on frame.
  The offset must respect all MAC headers, VLAN tags and other
  protocol headers accordingly. The correction field update can
  consider delays up to one second. So PTP frame needs to be
  filtered and parsed, and written timestamp into Sync frame
  originTimestamp field.

The operation of API dpni_set_single_step_cfg() has to be done
when no one-step timestamping frames are in flight. So we have
to make sure the last one-step timestamping frame has already
been transmitted on hardware before starting to send the current
one. The resolution is,

- Utilize skb->cb[0] to mark timestamping request per packet.
  If it is one-step timestamping PTP sync packet, queue to skb queue.
  If not, transmit immediately.

- Schedule a work to transmit skbs in skb queue.

- mutex lock is used to ensure the last one-step timestamping packet
  has already been transmitted on hardware through TX confirmation queue
  before transmitting current packet.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch is a preparation for next hardware one-step timestamping
support. For DPAA2, the one step timestamping configuration on
hardware registers has to be done when there is no one-step timestamping
packet in flight. So we will have to use workqueue and skb queue
for such packets transmitting, to make sure waiting the last packet has
already been sent on hardware, and starting to transmit the current one.

So the tx timestamping flag in private data may not reflect the actual
request for the one-step timestamping packets of skb queue. This also
affects skb headroom allocation. Let's use skb->cb[0] to mark the
timestamping request for each skb.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Invoke dpaa2_eth_enable_tx_tstamp() once in code after building FD,
rather than calling it in dpaa2_eth_build_single_fd(),
dpaa2_eth_build_sg_fd_single_buf(), and dpaa2_eth_build_sg_fd().
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Define a global ptp_qoriq structure pointer, and export to use.
The ptp clock operations will be used in dpaa2-eth driver.
For example, supporting one step timestamping needs to write
current time to hardware frame annotation before sending and
then hardware inserts the delay time on frame during sending.
So in driver, at least clock gettime operation will be needed
to make sure right time is written to hardware frame annotation
for one step timestamping.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch is to add APIs of 1588 single step timestamping.

- dpni_set_single_step_cfg
- dpni_get_single_step_cfg
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In the function ovs_ct_limit_exit, there is already a helper vaibale
which could be reused to improve the readability, so i fix it in this
patch.
Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Earlier commit 316cdaa1 ("net: add option to not create fall-back
tunnels in root-ns as well") removed the CONFIG_SYSCTL to enable the
kernel-commandline to work. However, this variable gets defined only
when CONFIG_SYSCTL option is selected.

With this change the behavior would default to creating fall-back
tunnels in all namespaces when CONFIG_SYSCTL is not selected and
the kernel commandline option will be ignored.

Fixes: 316cdaa1 ("net: add option to not create fall-back tunnels in root-ns as well")
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: David S. Miller <davem@davemloft.net>

Randy Dunlap says:

====================
net: various: delete duplicated words

[PATCH 1/7 net-next] net: core: delete duplicated words
[PATCH 2/7 net-next] net: rds: delete duplicated words
[PATCH 3/7 net-next] net: ipv6: delete duplicated words
[PATCH 4/7 net-next] net: bluetooth: delete duplicated words
[PATCH 5/7 net-next] net: tipc: delete duplicated words
[PATCH 6/7 net-next] net: atm: delete duplicated words
[PATCH 7/7 net-next] net: bridge: delete duplicated words
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in net/bridge/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: Nikolay Aleksandrov <nikolay@nvidia.com>
Cc: bridge@lists.linux-foundation.org
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in net/atm/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Chas Williams <3chas3@gmail.com>
Cc: linux-atm-general@lists.sourceforge.net
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in net/tipc/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jon Maloy <jmaloy@redhat.com>
Cc: Ying Xue <ying.xue@windriver.com>
Cc: tipc-discussion@lists.sourceforge.net
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in net/bluetooth/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in net/ipv6/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in net/rds/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Cc: linux-rdma@vger.kernel.org
Cc: rds-devel@oss.oracle.com
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in net/core/.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commit 550f4d46.

adapter->from_passive_init may be changed in ibmvnic_handle_crq
while ibmvnic_reset_init is waiting for the completion of
adapter->init_done.
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Tuong Lien says:

====================
tipc: add more features to TIPC encryption

This series adds some new features to TIPC encryption:

- Patch 1 ("tipc: optimize key switching time and logic") optimizes the
code and logic in preparation for the following commits.

- Patch 2 ("tipc: introduce encryption master key") introduces support
of 'master key' for authentication of new nodes and key exchange. A
master key can be set/changed by user via netlink (eg. using the same
'tipc node set key' command in iproute2/tipc).

- Patch 3 ("tipc: add automatic session key exchange") allows a session
key to be securely exchanged between nodes as needed.

- Patch 4 ("tipc: add automatic rekeying for encryption key") adds
automatic 'rekeying' of session keys a specific interval. The new key
will be distributed automatically to peer nodes, so become active then.
The rekeying interval is configurable via netlink as well.

v2: update the "tipc: add automatic session key exchange" patch to fix
"implicit declaration" issue when built without "CONFIG_TIPC_CRYPTO".

v3: update the patches according to David comments by using the
"genl_info->extack" for messages in response to netlink user config
requests.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Rekeying is required for security since a key is less secure when using
for a long time. Also, key will be detached when its nonce value (or
seqno ...) is exhausted. We now make the rekeying process automatic and
configurable by user.

Basically, TIPC will at a specific interval generate a new key by using
the kernel 'Random Number Generator' cipher, then attach it as the node
TX key and securely distribute to others in the cluster as RX keys (-
the key exchange). The automatic key switching will then take over, and
make the new key active shortly. Afterwards, the traffic from this node
will be encrypted with the new session key. The same can happen in peer
nodes but not necessarily at the same time.

For simplicity, the automatically generated key will be initiated as a
per node key. It is not too hard to also support a cluster key rekeying
(e.g. a given node will generate a unique cluster key and update to the
others in the cluster...), but that doesn't bring much benefit, while a
per-node key is even more secure.

We also enable user to force a rekeying or change the rekeying interval
via netlink, the new 'set key' command option: 'TIPC_NLA_NODE_REKEYING'
is added for these purposes as follows:
- A value >= 1 will be set as the rekeying interval (in minutes);
- A value of 0 will disable the rekeying;
- A value of 'TIPC_REKEYING_NOW' (~0) will force an immediate rekeying;

The default rekeying interval is (60 * 24) minutes i.e. done every day.
There isn't any restriction for the value but user shouldn't set it too
small or too large which results in an "ineffective" rekeying (thats ok
for testing though).
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

With support from the master key option in the previous commit, it
becomes easy to make frequent updates/exchanges of session keys between
authenticated cluster nodes.
Basically, there are two situations where the key exchange will take in
place:

- When a new node joins the cluster (with the master key), it will need
  to get its peer's TX key, so that be able to decrypt further messages
  from that peer.

- When a new session key is generated (by either user manual setting or
  later automatic rekeying feature), the key will be distributed to all
  peer nodes in the cluster.

A key to be exchanged is encapsulated in the data part of a 'MSG_CRYPTO
/KEY_DISTR_MSG' TIPC v2 message, then xmit-ed as usual and encrypted by
using the master key before sending out. Upon receipt of the message it
will be decrypted in the same way as regular messages, then attached as
the sender's RX key in the receiver node.

In this way, the key exchange is reliable by the link layer, as well as
security, integrity and authenticity by the crypto layer.

Also, the forward security will be easily achieved by user changing the
master key actively but this should not be required very frequently.

The key exchange feature is independent on the presence of a master key
Note however that the master key still is needed for new nodes to be
able to join the cluster. It is also optional, and can be turned off/on
via the sysfs: 'net/tipc/key_exchange_enabled' [default 1: enabled].

Backward compatibility is guaranteed because for nodes that do not have
master key support, key exchange using master key ie. tx_key = 0 if any
will be shortly discarded at the message validation step. In other
words, the key exchange feature will be automatically disabled to those
nodes.

v2: fix the "implicit declaration of function 'tipc_crypto_key_flush'"
error in node.c. The function only exists when built with the TIPC
"CONFIG_TIPC_CRYPTO" option.

v3: use 'info->extack' for a message emitted due to netlink operations
instead (- David's comment).
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>