Re: [dpdk-dev] [PATCH 1/2] security: enforce semantics for Tx inline processing

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> 
> From: Nithin Dabilpuram <ndabilpuram@marvell.com>
> 
> For Tx inline processing, when RTE_SECURITY_TX_OLOAD_NEED_MDATA is
> set, rte_security_set_pkt_metadata() needs to be called for pkts
> to associate a Security session with a mbuf before submitting
> to Ethdev Tx. This is apart from setting PKT_TX_SEC_OFFLOAD in
> mbuf.ol_flags. rte_security_set_pkt_metadata() is also used to
> set some opaque metadata in mbuf for PMD's use.
> This patch updates documentation that rte_security_set_pkt_metadata()
> should be called only with mbuf containing Layer 3 and above data.
> This behaviour is consistent with existing PMD's such as ixgbe.
> 
> On Tx, not all net PMD's/HW can parse packet and identify
> L2 header and L3 header locations on Tx. This is inline with other
> Tx offloads requirements such as L3 checksum, L4 checksum offload,
> etc, where mbuf.l2_len, mbuf.l3_len etc, needs to be set for
> HW to be able to generate checksum. Since Inline IPSec is also
> such a Tx offload, some PMD's at least need mbuf.l2_len to be
> valid to find L3 header and perform Outbound IPSec processing.
> Hence, this patch updates documentation to enforce setting
> mbuf.l2_len while setting PKT_TX_SEC_OFFLOAD in mbuf.ol_flags
> for Inline IPSec Crypto / Protocol offload processing to
> work on Tx.
> 
> Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
> Reviewed-by: Akhil Goyal <gakhil@marvell.com>
> ---
>  doc/guides/nics/features.rst           | 2 ++
>  doc/guides/prog_guide/rte_security.rst | 6 +++++-
>  lib/mbuf/rte_mbuf_core.h               | 2 ++
>  3 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/guides/nics/features.rst b/doc/guides/nics/features.rst
> index 403c2b03a..414baf14f 100644
> --- a/doc/guides/nics/features.rst
> +++ b/doc/guides/nics/features.rst
> @@ -430,6 +430,7 @@ of protocol operations. See Security library and PMD documentation for more deta
> 
>  * **[uses]       rte_eth_rxconf,rte_eth_rxmode**: ``offloads:DEV_RX_OFFLOAD_SECURITY``,
>  * **[uses]       rte_eth_txconf,rte_eth_txmode**: ``offloads:DEV_TX_OFFLOAD_SECURITY``.
> +* **[uses]       mbuf**: ``mbuf.l2_len``.
>  * **[implements] rte_security_ops**: ``session_create``, ``session_update``,
>    ``session_stats_get``, ``session_destroy``, ``set_pkt_metadata``, ``capabilities_get``.
>  * **[provides] rte_eth_dev_info**: ``rx_offload_capa,rx_queue_offload_capa:DEV_RX_OFFLOAD_SECURITY``,
> @@ -451,6 +452,7 @@ protocol operations. See security library and PMD documentation for more details
> 
>  * **[uses]       rte_eth_rxconf,rte_eth_rxmode**: ``offloads:DEV_RX_OFFLOAD_SECURITY``,
>  * **[uses]       rte_eth_txconf,rte_eth_txmode**: ``offloads:DEV_TX_OFFLOAD_SECURITY``.
> +* **[uses]       mbuf**: ``mbuf.l2_len``.
>  * **[implements] rte_security_ops**: ``session_create``, ``session_update``,
>    ``session_stats_get``, ``session_destroy``, ``set_pkt_metadata``, ``get_userdata``,
>    ``capabilities_get``.
> diff --git a/doc/guides/prog_guide/rte_security.rst b/doc/guides/prog_guide/rte_security.rst
> index f72bc8a78..7b68c698d 100644
> --- a/doc/guides/prog_guide/rte_security.rst
> +++ b/doc/guides/prog_guide/rte_security.rst
> @@ -560,7 +560,11 @@ created by the application is attached to the security session by the API
> 
>  For Inline Crypto and Inline protocol offload, device specific defined metadata is
>  updated in the mbuf using ``rte_security_set_pkt_metadata()`` if
> -``DEV_TX_OFFLOAD_SEC_NEED_MDATA`` is set.
> +``RTE_SECURITY_TX_OLOAD_NEED_MDATA`` is set. ``rte_security_set_pkt_metadata()``
> +should be called on mbuf only with Layer 3 and above data present and
> +``mbuf.data_off`` should be pointing to Layer 3 Header.

Hmm... not sure why mbuf.data_off should point to L3 hdr.
Who will add L2 hdr to the packet in that case?
Or did you mean ``mbuf.data_off + mbuf.l2_len`` here?

> Once called,
> +Layer 3 and above data cannot be modified or moved around unless
> +``rte_security_set_pkt_metadata()`` is called again.
> 
>  For inline protocol offloaded ingress traffic, the application can register a
>  pointer, ``userdata`` , in the security session. When the packet is received,
> diff --git a/lib/mbuf/rte_mbuf_core.h b/lib/mbuf/rte_mbuf_core.h
> index bb38d7f58..9d8e3ddc8 100644
> --- a/lib/mbuf/rte_mbuf_core.h
> +++ b/lib/mbuf/rte_mbuf_core.h
> @@ -228,6 +228,8 @@ extern "C" {
> 
>  /**
>   * Request security offload processing on the TX packet.
> + * To use Tx security offload, the user needs to fill l2_len in mbuf
> + * indicating L2 header size and where L3 header starts.
>   */
>  #define PKT_TX_SEC_OFFLOAD	(1ULL << 43)
> 
> --
> 2.25.1