3. AES-NI GCM Crypto Poll Mode Driver

The AES-NI GCM PMD (librte_pmd_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).

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

  • Chained mbufs are supported but only out-of-place (destination mbuf must be contiguous).
  • 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 v0.46, which can be downloaded in https://github.com/01org/intel-ipsec-mb/archive/v0.46.zip.

make

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

Table 3.1 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+ Multi-buffer library 0.46+

3.4. Initialization

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

  • Export the environmental variable AESNI_MULTI_BUFFER_LIB_PATH with the path where the library was extracted.
  • Build the multi buffer library (explained in Installation section).
  • Set CONFIG_RTE_LIBRTE_PMD_AESNI_GCM=y in config/common_base.

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:

./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"