nfp: add framework to support ipsec offloading

A new metadata type and config structure are introduced to
interact with firmware to support ipsec offloading. This
feature relies on specific firmware that supports ipsec
encrypt/decrypt by advertising related capability bit.

The xfrm callbacks which interact with upper layer are
implemented in the following patch.

Based on initial work of Norm Bagley <norman.bagley@netronome.com>.

Signed-off-by: Huanhuan Wang <huanhuan.wang@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: tls: implement the stream sync RX resync

The simple RX resync strategy controlled by the kernel does not
guarantee as good results as if the device helps by detecting
the potential record boundaries and keeping track of them.

We've called this strategy stream scan in the tls-offload doc.

Implement this strategy for the NFP. The device sends a request
for record boundary confirmation, which is then recorded in
per-TLS socket state and responded to once record is reached.
Because the device keeps track of records passing after the
request was sent the response is not as latency sensitive as
when kernel just tries to tell the device the information
about the next record.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: tls: make use of kernel-driven TX resync

When TCP stream gets out of sync (driver stops receiving skbs
with expected TCP sequence numbers) request a TX resync from
the kernel.

We try to distinguish retransmissions from missed transmissions
by comparing the sequence number to expected - if it's further
than the expected one - we probably missed packets.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: tls: enable TLS RX offload

Set ethtool TLS RX feature based on NIC capabilities, and enable
TLS RX when connections are added for decryption.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: tls: add datapath support for TLS TX

Prepend connection handle to each transmitted TLS packet.

For each connection, the driver tracks the next sequence number
expected. If an out of order packet is observed, the driver calls into
the TLS kernel code to reencrypt that particular skb.

Signed-off-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp: add tls init code

Add FW ABI defines and code for basic init of TLS offload.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>