[RFC PATCH 3/3] cryptodev: add details of datapath handling of TLS records

[Anoob Joseph]

TLS/DTLS record processing requires content type to be provided per
packet (for record write operation). Extend usage of
rte_crypto_op.aux_flags for the same purpose.

Signed-off-by: Akhil Goyal <gakhil at marvell.com>
Signed-off-by: Anoob Joseph <anoobj at marvell.com>
Signed-off-by: Vidya Sagar Velumuri <vvelumuri at marvell.com>
---
 doc/guides/prog_guide/rte_security.rst | 10 ++++++++++
 lib/cryptodev/rte_crypto.h             |  6 ++++++
 2 files changed, 16 insertions(+)

diff --git a/doc/guides/prog_guide/rte_security.rst b/doc/guides/prog_guide/rte_security.rst
index 7716d7239f..6cb69bc949 100644
--- a/doc/guides/prog_guide/rte_security.rst
+++ b/doc/guides/prog_guide/rte_security.rst
@@ -451,6 +451,16 @@ Protocol. The TLS Record Protocol provides connection security that has two basi
                   V                              V
             TLSCiphertext                  TLSPlaintext
 
+TLS and DTLS header formation (in record write operation) would depend on the
+type of content. It is a per packet variable and would need to be handled by
+the same session. Application may pass this info to a cryptodev performing
+lookaside protocol offload by passing the same in ``rte_crypto_op.aux_flags``.
+
+In record read operation, application is required to preserve any info it may
+need from the TLS/DTLS header (such as content type and sequence number) as the
+cryptodev would remove the header and padding as part of the lookaside protocol
+processing.
+
 Supported Versions
 ^^^^^^^^^^^^^^^^^^
 
diff --git a/lib/cryptodev/rte_crypto.h b/lib/cryptodev/rte_crypto.h
index 9b8d0331a4..7c12a2b705 100644
--- a/lib/cryptodev/rte_crypto.h
+++ b/lib/cryptodev/rte_crypto.h
@@ -101,6 +101,12 @@ struct rte_crypto_op {
 			/**< Operation specific auxiliary/additional flags.
 			 * These flags carry additional information from the
 			 * operation. Processing of the same is optional.
+			 *
+			 * With TLS record offload (RTE_SECURITY_PROTOCOL_TLS_RECORD),
+			 * application would be required to provide the message
+			 * type of the input provided. The 'aux_flags' field
+			 * can be used for passing the same. Message types are
+			 * listed as RTE_TLS_TYPE_* and RTE_DTLS_TYPE_*.
 			 */
 			uint8_t reserved[2];
 			/**< Reserved bytes to fill 64 bits for
-- 
2.25.1