[RFC] cryptodev: enable BPI+ for Cablelabs DOCSIS security spec

[RFC] cryptodev: enable BPI+ for Cablelabs DOCSIS security spec

[Trahe, Fiona]

Proposal to extend the DPDK cryptodev API to enable processing of packets according to the Baseline Privacy Interface Plus (BPI+) Specification described in the security specification of the Cablelabs Data-over-Cable Service Interface Specification (DOCSIS).

Brief summary of BPI+ symmetric cryptography requirements:
BPI+ cryptography uses a block cipher (AES-CBC/DES-CBC) to encrypt/decrypt all the whole blocks in the packet. However the data length is not always a block-multiple, so where there is a final block less than the full block size this residual block requires special handling using AES-CFB/DES-CFB mode. Similar special handling is specified where there is only one block, smaller than the block size for the cipher. See spec for further details.
https://apps.cablelabs.com/specification/docsis-3-1-security-specification/

Proposal:
Add new elements in the enum rte_crypto_cipher_algorithm.
Note elements of this enum are actually a combination of an algorithm (AES, 3DES, etc) and mode (CBC, CTR, etc). The new DOCSISBPI mode is used to convey to the PMD that the mode applied should be the specific combination of CBC and CFB required by the DOCSIS Baseline Privacy Plus Spec.
There are no other API changes needed.

The API patch is below. 
Thoughts?


diff --git a/lib/librte_cryptodev/rte_crypto_sym.h b/lib/librte_cryptodev/rte_crypto_sym.h
index d694723..92fa568 100644
--- a/lib/librte_cryptodev/rte_crypto_sym.h
+++ b/lib/librte_cryptodev/rte_crypto_sym.h
@@ -105,6 +105,15 @@ enum rte_crypto_cipher_algorithm {
       RTE_CRYPTO_CIPHER_DES_CBC,
       /**< DES algorithm in CBC mode */

+       RTE_CRYPTO_CIPHER_DES_DOCSISBPI,
+       /**< DES algorithm using modes required by DOCSIS Baseline Privacy Plus Spec. */
+
+       RTE_CRYPTO_CIPHER_AES_DOCSISBPI,
+       /**< AES algorithm using modes required by DOCSIS Baseline Privacy Plus Spec.  */
+
        RTE_CRYPTO_CIPHER_LIST_END
};