Merge branch 'add-basic-psp-encryption-for-tcp-connections'

Merge branch 'add-basic-psp-encryption-for-tcp-connections'

Daniel Zahka says:

==================
add basic PSP encryption for TCP connections

This is v13 of the PSP RFC [1] posted by Jakub Kicinski one year
ago. General developments since v1 include a fork of packetdrill [2]
with support for PSP added, as well as some test cases, and an
implementation of PSP key exchange and connection upgrade [3]
integrated into the fbthrift RPC library. Both [2] and [3] have been
tested on server platforms with PSP-capable CX7 NICs. Below is the
cover letter from the original RFC:

Add support for PSP encryption of TCP connections.

PSP is a protocol out of Google:
https://github.com/google/psp/blob/main/doc/PSP_Arch_Spec.pdf
which shares some similarities with IPsec. I added some more info
in the first patch so I'll keep it short here.

The protocol can work in multiple modes including tunneling.
But I'm mostly interested in using it as TLS replacement because
of its superior offload characteristics. So this patch does three
things:

 - it adds "core" PSP code
   PSP is offload-centric, and requires some additional care and
   feeding, so first chunk of the code exposes device info.
   This part can be reused by PSP implementations in xfrm, tunneling etc.

 - TCP integration TLS style
   Reuse some of the existing concepts from TLS offload, such as
   attaching crypto state to a socket, marking skbs as "decrypted",
   egress validation. PSP does not prescribe key exchange protocols.
   To use PSP as a more efficient TLS offload we intend to perform
   a TLS handshake ("inline" in the same TCP connection) and negotiate
   switching to PSP based on capabilities of both endpoints.
   This is also why I'm not including a software implementation.
   Nobody would use it in production, software TLS is faster,
   it has larger crypto records.

 - mlx5 implementation
   That's mostly other people's work, not 100% sure those folks
   consider it ready hence the RFC in the title. But it works :)

Not posted, queued a branch [4] are follow up pieces:
 - standard stats
 - netdevsim implementation and tests

[1] https://lore.kernel.org/netdev/20240510030435.120935-1-kuba@kernel.org/
[2] https://github.com/danieldzahka/packetdrill
[3] https://github.com/danieldzahka/fbthrift/tree/dzahka/psp
[4] https://github.com/kuba-moo/linux/tree/psp

Comments we intend to defer to future series:
   - we prefer to keep the version field in the tx-assoc netlink
     request, because it makes parsing keys require less state early
     on, but we are willing to change in the next version of this
     series.
   - using a static branch to wrap psp_enqueue_set_decrypted() and
     other functions called from tcp.
   - using INDIRECT_CALL for tls/psp in sk_validate_xmit_skb(). We
     prefer to address this in a dedicated patch series, so that this
     series does not need to modify the way tls_validate_xmit_skb() is
     declared and stubbed out.

v12: https://lore.kernel.org/netdev/20250916000559.1320151-1-kuba@kernel.org/
v11: https://lore.kernel.org/20250911014735.118695-1-daniel.zahka@gmail.com
v10: https://lore.kernel.org/netdev/20250828162953.2707727-1-daniel.zahka@gmail.com/
v9: https://lore.kernel.org/netdev/20250827155340.2738246-1-daniel.zahka@gmail.com/
v8: https://lore.kernel.org/netdev/20250825200112.1750547-1-daniel.zahka@gmail.com/
v7: https://lore.kernel.org/netdev/20250820113120.992829-1-daniel.zahka@gmail.com/
v6: https://lore.kernel.org/netdev/20250812003009.2455540-1-daniel.zahka@gmail.com/
v5: https://lore.kernel.org/netdev/20250723203454.519540-1-daniel.zahka@gmail.com/
v4: https://lore.kernel.org/netdev/20250716144551.3646755-1-daniel.zahka@gmail.com/
v3: https://lore.kernel.org/netdev/20250702171326.3265825-1-daniel.zahka@gmail.com/
v2: https://lore.kernel.org/netdev/20250625135210.2975231-1-daniel.zahka@gmail.com/
v1: https://lore.kernel.org/netdev/20240510030435.120935-1-kuba@kernel.org/
==================

Links: https://patch.msgid.link/20250917000954.859376-1-daniel.zahka@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
* add-basic-psp-encryption-for-tcp-connections:
  net/mlx5e: Implement PSP key_rotate operation
  net/mlx5e: Add Rx data path offload
  psp: provide decapsulation and receive helper for drivers
  net/mlx5e: Configure PSP Rx flow steering rules
  net/mlx5e: Add PSP steering in local NIC RX
  net/mlx5e: Implement PSP Tx data path
  psp: provide encapsulation helper for drivers
  net/mlx5e: Implement PSP operations .assoc_add and .assoc_del
  net/mlx5e: Support PSP offload functionality
  psp: track generations of device key
  net: psp: update the TCP MSS to reflect PSP packet overhead
  net: psp: add socket security association code
  net: tcp: allow tcp_timewait_sock to validate skbs before handing to device
  net: move sk_validate_xmit_skb() to net/core/dev.c
  psp: add op for rotation of device key
  tcp: add datapath logic for PSP with inline key exchange
  net: modify core data structures for PSP datapath support
  psp: base PSP device support
  psp: add documentation