3. AES-NI GCM Crypto Poll Mode Driver

The AES-NI GCM PMD (librte_crypto_aesni_gcm) provides poll mode crypto driver support for utilizing Intel multi buffer library (see AES-NI Multi-buffer PMD documentation to learn more about it, including installation).

The AES-NI GCM PMD supports synchronous mode of operation with rte_cryptodev_sym_cpu_crypto_process function call for both AES-GCM and GMAC, however GMAC support is limited to one segment per operation. Please refer to rte_crypto programmer’s guide for more detail.

3.1. Features

AESNI GCM PMD has support for:

Authentication algorithms:

  • RTE_CRYPTO_AUTH_AES_GMAC

AEAD algorithms:

  • RTE_CRYPTO_AEAD_AES_GCM

3.2. Limitations

  • In out-of-place operations, chained destination mbufs are not supported.

  • Cipher only is not supported.

3.3. Installation

To build DPDK with the AESNI_GCM_PMD the user is required to download the multi-buffer library from here and compile it on their user system before building DPDK. The latest version of the library supported by this PMD is v0.55, which can be downloaded in https://github.com/01org/intel-ipsec-mb/archive/v0.55.zip.

make
make install

The library requires NASM to be built. Depending on the library version, it might require a minimum NASM version (e.g. v0.54 requires at least NASM 2.14).

NASM is packaged for different OS. However, on some OS the version is too old, so a manual installation is required. In that case, NASM can be downloaded from NASM website. Once it is downloaded, extract it and follow these steps:

./configure
make
make install

Note

Compilation of the Multi-Buffer library is broken when GCC < 5.0, if library <= v0.53. If a lower GCC version than 5.0, the workaround proposed by the following link should be used: https://github.com/intel/intel-ipsec-mb/issues/40.

As a reference, the following table shows a mapping between the past DPDK versions and the external crypto libraries supported by them:

Table 3.2 DPDK and external crypto library version compatibility

DPDK version

Crypto library version

16.04 - 16.11

Multi-buffer library 0.43 - 0.44

17.02 - 17.05

ISA-L Crypto v2.18

17.08 - 18.02

Multi-buffer library 0.46 - 0.48

18.05 - 19.02

Multi-buffer library 0.49 - 0.52

19.05+

Multi-buffer library 0.52 - 0.55

3.4. Initialization

In order to enable this virtual crypto PMD, user must:

  • Build the multi buffer library (explained in Installation section).

To use the PMD in an application, user must:

  • Call rte_vdev_init(“crypto_aesni_gcm”) within the application.

  • Use –vdev=”crypto_aesni_gcm” in the EAL options, which will call rte_vdev_init() internally.

The following parameters (all optional) can be provided in the previous two calls:

  • socket_id: Specify the socket where the memory for the device is going to be allocated (by default, socket_id will be the socket where the core that is creating the PMD is running on).

  • max_nb_queue_pairs: Specify the maximum number of queue pairs in the device (8 by default).

  • max_nb_sessions: Specify the maximum number of sessions that can be created (2048 by default).

Example:

./dpdk-l2fwd-crypto -l 1 -n 4 --vdev="crypto_aesni_gcm,socket_id=0,max_nb_sessions=128" \
-- -p 1 --cdev SW --chain AEAD --aead_algo "aes-gcm"