null.rst revision 97f17497
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29
30Null Crypto Poll Mode Driver
31============================
32
33The Null Crypto PMD (**librte_pmd_null_crypto**) provides a crypto poll mode
34driver which provides a minimal implementation for a software crypto device. As
35a null device it does not modify the data in the mbuf on which the crypto
36operation is to operate and it only has support for a single cipher and
37authentication algorithm.
38
39When a burst of mbufs is submitted to a Null Crypto PMD for processing then
40each mbuf in the burst will be enqueued in an internal buffer for collection on
41a dequeue call as long as the mbuf has a valid rte_mbuf_offload operation with
42a valid rte_cryptodev_session or rte_crypto_xform chain of operations.
43
44Features
45--------
46
47Modes:
48
49* RTE_CRYPTO_XFORM_CIPHER ONLY
50* RTE_CRYPTO_XFORM_AUTH ONLY
51* RTE_CRYPTO_XFORM_CIPHER THEN RTE_CRYPTO_XFORM_AUTH
52* RTE_CRYPTO_XFORM_AUTH THEN RTE_CRYPTO_XFORM_CIPHER
53
54Cipher algorithms:
55
56* RTE_CRYPTO_CIPHER_NULL
57
58Authentication algorithms:
59
60* RTE_CRYPTO_AUTH_NULL
61
62Limitations
63-----------
64
65* Only in-place is currently supported (destination address is the same as
66  source address).
67
68Installation
69------------
70
71The Null Crypto PMD is enabled and built by default in both the Linux and
72FreeBSD builds.
73
74Initialization
75--------------
76
77To use the PMD in an application, user must:
78
79* Call rte_eal_vdev_init("cryptodev_null_pmd") within the application.
80
81* Use --vdev="cryptodev_null_pmd" in the EAL options, which will call rte_eal_vdev_init() internally.
82
83The following parameters (all optional) can be provided in the previous two calls:
84
85* socket_id: Specify the socket where the memory for the device is going to be allocated
86  (by default, socket_id will be the socket where the core that is creating the PMD is running on).
87
88* max_nb_queue_pairs: Specify the maximum number of queue pairs in the device (8 by default).
89
90* max_nb_sessions: Specify the maximum number of sessions that can be created (2048 by default).
91
92Example:
93
94.. code-block:: console
95
96    ./l2fwd-crypto -c 40 -n 4 --vdev="cryptodev_null_pmd,socket_id=1,max_nb_sessions=128"
97