18. Cryptography Device Library

The cryptodev library provides a Crypto device framework for management and provisioning of hardware and software Crypto poll mode drivers, defining generic APIs which support a number of different Crypto operations. The framework currently only supports cipher, authentication, chained cipher/authentication and AEAD symmetric and asymmetric Crypto operations.

18.1. Design Principles

The cryptodev library follows the same basic principles as those used in DPDK’s Ethernet Device framework. The Crypto framework provides a generic Crypto device framework which supports both physical (hardware) and virtual (software) Crypto devices as well as a generic Crypto API which allows Crypto devices to be managed and configured and supports Crypto operations to be provisioned on Crypto poll mode driver.

18.2. Device Management

18.2.1. Device Creation

Physical Crypto devices are discovered during the PCI probe/enumeration of the EAL function which is executed at DPDK initialization, based on their PCI device identifier, each unique PCI BDF (bus/bridge, device, function). Specific physical Crypto devices, like other physical devices in DPDK can be listed using the EAL command line options.

Virtual devices can be created by two mechanisms, either using the EAL command line options or from within the application using an EAL API directly.

From the command line using the –vdev EAL option

--vdev  'crypto_aesni_mb0,max_nb_queue_pairs=2,socket_id=0'

Note

• If DPDK application requires multiple software crypto PMD devices then required number of --vdev with appropriate libraries are to be added.
• An Application with crypto PMD instances sharing the same library requires unique ID.

Example: --vdev  'crypto_aesni_mb0' --vdev  'crypto_aesni_mb1'

Or using the rte_vdev_init API within the application code.

rte_vdev_init("crypto_aesni_mb",
                  "max_nb_queue_pairs=2,socket_id=0")

All virtual Crypto devices support the following initialization parameters:

• max_nb_queue_pairs - maximum number of queue pairs supported by the device.
• socket_id - socket on which to allocate the device resources on.

18.2.2. Device Identification

Each device, whether virtual or physical is uniquely designated by two identifiers:

• A unique device index used to designate the Crypto device in all functions exported by the cryptodev API.
• A device name used to designate the Crypto device in console messages, for administration or debugging purposes. For ease of use, the port name includes the port index.

18.2.3. Device Configuration

The configuration of each Crypto device includes the following operations:

• Allocation of resources, including hardware resources if a physical device.
• Resetting the device into a well-known default state.
• Initialization of statistics counters.

The rte_cryptodev_configure API is used to configure a Crypto device.

int rte_cryptodev_configure(uint8_t dev_id,
                            struct rte_cryptodev_config *config)

The rte_cryptodev_config structure is used to pass the configuration parameters for socket selection and number of queue pairs.

struct rte_cryptodev_config {
    int socket_id;
    /**< Socket to allocate resources on */
    uint16_t nb_queue_pairs;
    /**< Number of queue pairs to configure on device */
};

18.2.4. Configuration of Queue Pairs

Each Crypto devices queue pair is individually configured through the rte_cryptodev_queue_pair_setup API. Each queue pairs resources may be allocated on a specified socket.

 int rte_cryptodev_queue_pair_setup(uint8_t dev_id, uint16_t queue_pair_id,
             const struct rte_cryptodev_qp_conf *qp_conf,
             int socket_id)

struct rte_cryptodev_qp_conf {
     uint32_t nb_descriptors; /**< Number of descriptors per queue pair */
     struct rte_mempool *mp_session;
     /**< The mempool for creating session in sessionless mode */
     struct rte_mempool *mp_session_private;
     /**< The mempool for creating sess private data in sessionless mode */
 };

The fields mp_session and mp_session_private are used for creating temporary session to process the crypto operations in the session-less mode. They can be the same other different mempools. Please note not all Cryptodev PMDs supports session-less mode.

18.2.5. Logical Cores, Memory and Queues Pair Relationships

The Crypto device Library as the Poll Mode Driver library support NUMA for when a processor’s logical cores and interfaces utilize its local memory. Therefore Crypto operations, and in the case of symmetric Crypto operations, the session and the mbuf being operated on, should be allocated from memory pools created in the local memory. The buffers should, if possible, remain on the local processor to obtain the best performance results and buffer descriptors should be populated with mbufs allocated from a mempool allocated from local memory.

The run-to-completion model also performs better, especially in the case of virtual Crypto devices, if the Crypto operation and session and data buffer is in local memory instead of a remote processor’s memory. This is also true for the pipe-line model provided all logical cores used are located on the same processor.

Multiple logical cores should never share the same queue pair for enqueuing operations or dequeuing operations on the same Crypto device since this would require global locks and hinder performance. It is however possible to use a different logical core to dequeue an operation on a queue pair from the logical core which it was enqueued on. This means that a crypto burst enqueue/dequeue APIs are a logical place to transition from one logical core to another in a packet processing pipeline.

18.3. Device Features and Capabilities

Crypto devices define their functionality through two mechanisms, global device features and algorithm capabilities. Global devices features identify device wide level features which are applicable to the whole device such as the device having hardware acceleration or supporting symmetric and/or asymmetric Crypto operations.

The capabilities mechanism defines the individual algorithms/functions which the device supports, such as a specific symmetric Crypto cipher, authentication operation or Authenticated Encryption with Associated Data (AEAD) operation.

18.3.1. Device Features

Currently the following Crypto device features are defined:

• Symmetric Crypto operations
• Asymmetric Crypto operations
• Chaining of symmetric Crypto operations
• SSE accelerated SIMD vector operations
• AVX accelerated SIMD vector operations
• AVX2 accelerated SIMD vector operations
• AESNI accelerated instructions
• Hardware off-load processing

18.3.2. Device Operation Capabilities

Crypto capabilities which identify particular algorithm which the Crypto PMD supports are defined by the operation type, the operation transform, the transform identifier and then the particulars of the transform. For the full scope of the Crypto capability see the definition of the structure in the DPDK API Reference.

struct rte_cryptodev_capabilities;

Each Crypto poll mode driver defines its own private array of capabilities for the operations it supports. Below is an example of the capabilities for a PMD which supports the authentication algorithm SHA1_HMAC and the cipher algorithm AES_CBC.

static const struct rte_cryptodev_capabilities pmd_capabilities[] = {
    {    /* SHA1 HMAC */
        .op = RTE_CRYPTO_OP_TYPE_SYMMETRIC,
        .sym = {
            .xform_type = RTE_CRYPTO_SYM_XFORM_AUTH,
            .auth = {
                .algo = RTE_CRYPTO_AUTH_SHA1_HMAC,
                .block_size = 64,
                .key_size = {
                    .min = 64,
                    .max = 64,
                    .increment = 0
                },
                .digest_size = {
                    .min = 12,
                    .max = 12,
                    .increment = 0
                },
                .aad_size = { 0 },
                .iv_size = { 0 }
            }
        }
    },
    {    /* AES CBC */
        .op = RTE_CRYPTO_OP_TYPE_SYMMETRIC,
        .sym = {
            .xform_type = RTE_CRYPTO_SYM_XFORM_CIPHER,
            .cipher = {
                .algo = RTE_CRYPTO_CIPHER_AES_CBC,
                .block_size = 16,
                .key_size = {
                    .min = 16,
                    .max = 32,
                    .increment = 8
                },
                .iv_size = {
                    .min = 16,
                    .max = 16,
                    .increment = 0
                }
            }
        }
    }
}

18.3.3. Capabilities Discovery

Discovering the features and capabilities of a Crypto device poll mode driver is achieved through the rte_cryptodev_info_get function.

void rte_cryptodev_info_get(uint8_t dev_id,
                            struct rte_cryptodev_info *dev_info);

This allows the user to query a specific Crypto PMD and get all the device features and capabilities. The rte_cryptodev_info structure contains all the relevant information for the device.

struct rte_cryptodev_info {
    const char *driver_name;
    uint8_t driver_id;
    struct rte_device *device;

    uint64_t feature_flags;

    const struct rte_cryptodev_capabilities *capabilities;

    unsigned max_nb_queue_pairs;

    struct {
        unsigned max_nb_sessions;
    } sym;
};

18.4. Operation Processing

Scheduling of Crypto operations on DPDK’s application data path is performed using a burst oriented asynchronous API set. A queue pair on a Crypto device accepts a burst of Crypto operations using enqueue burst API. On physical Crypto devices the enqueue burst API will place the operations to be processed on the devices hardware input queue, for virtual devices the processing of the Crypto operations is usually completed during the enqueue call to the Crypto device. The dequeue burst API will retrieve any processed operations available from the queue pair on the Crypto device, from physical devices this is usually directly from the devices processed queue, and for virtual device’s from a rte_ring where processed operations are placed after being processed on the enqueue call.

18.4.1. Private data

For session-based operations, the set and get API provides a mechanism for an application to store and retrieve the private user data information stored along with the crypto session.

For example, suppose an application is submitting a crypto operation with a session associated and wants to indicate private user data information which is required to be used after completion of the crypto operation. In this case, the application can use the set API to set the user data and retrieve it using get API.

int rte_cryptodev_sym_session_set_user_data(
        struct rte_cryptodev_sym_session *sess, void *data, uint16_t size);

void * rte_cryptodev_sym_session_get_user_data(
        struct rte_cryptodev_sym_session *sess);

Please note the size passed to set API cannot be bigger than the predefined user_data_sz when creating the session header mempool, otherwise the function will return error. Also when user_data_sz was defined as 0 when creating the session header mempool, the get API will always return NULL.

For session-less mode, the private user data information can be placed along with the struct rte_crypto_op. The rte_crypto_op::private_data_offset indicates the start of private data information. The offset is counted from the start of the rte_crypto_op including other crypto information such as the IVs (since there can be an IV also for authentication).

18.4.2. User callback APIs

The add APIs configures a user callback function to be called for each burst of crypto ops received/sent on a given crypto device queue pair. The return value is a pointer that can be used later to remove the callback using remove API. Application is expected to register a callback function of type rte_cryptodev_callback_fn. Multiple callback functions can be added for a given queue pair. API does not restrict on maximum number of callbacks.

Callbacks registered by application would not survive rte_cryptodev_configure as it reinitializes the callback list. It is user responsibility to remove all installed callbacks before calling rte_cryptodev_configure to avoid possible memory leakage.

So, the application is expected to add user callback after rte_cryptodev_configure. The callbacks can also be added at the runtime. These callbacks get executed when rte_cryptodev_enqueue_burst/rte_cryptodev_dequeue_burst is called.

struct rte_cryptodev_cb *
        rte_cryptodev_add_enq_callback(uint8_t dev_id, uint16_t qp_id,
                                       rte_cryptodev_callback_fn cb_fn,
                                       void *cb_arg);

struct rte_cryptodev_cb *
        rte_cryptodev_add_deq_callback(uint8_t dev_id, uint16_t qp_id,
                                       rte_cryptodev_callback_fn cb_fn,
                                       void *cb_arg);

uint16_t (* rte_cryptodev_callback_fn)(uint16_t dev_id, uint16_t qp_id,
                                       struct rte_crypto_op **ops,
                                       uint16_t nb_ops, void *user_param);

The remove API removes a callback function added by rte_cryptodev_add_enq_callback/rte_cryptodev_add_deq_callback.

int rte_cryptodev_remove_enq_callback(uint8_t dev_id, uint16_t qp_id,
                                      struct rte_cryptodev_cb *cb);

int rte_cryptodev_remove_deq_callback(uint8_t dev_id, uint16_t qp_id,
                                      struct rte_cryptodev_cb *cb);

18.4.3. Enqueue / Dequeue Burst APIs

The burst enqueue API uses a Crypto device identifier and a queue pair identifier to specify the Crypto device queue pair to schedule the processing on. The nb_ops parameter is the number of operations to process which are supplied in the ops array of rte_crypto_op structures. The enqueue function returns the number of operations it actually enqueued for processing, a return value equal to nb_ops means that all packets have been enqueued.

uint16_t rte_cryptodev_enqueue_burst(uint8_t dev_id, uint16_t qp_id,
                                     struct rte_crypto_op **ops, uint16_t nb_ops)

The dequeue API uses the same format as the enqueue API of processed but the nb_ops and ops parameters are now used to specify the max processed operations the user wishes to retrieve and the location in which to store them. The API call returns the actual number of processed operations returned, this can never be larger than nb_ops.

uint16_t rte_cryptodev_dequeue_burst(uint8_t dev_id, uint16_t qp_id,
                                     struct rte_crypto_op **ops, uint16_t nb_ops)

18.4.4. Operation Representation

An Crypto operation is represented by an rte_crypto_op structure, which is a generic metadata container for all necessary information required for the Crypto operation to be processed on a particular Crypto device poll mode driver.

The operation structure includes the operation type, the operation status and the session type (session-based/less), a reference to the operation specific data, which can vary in size and content depending on the operation being provisioned. It also contains the source mempool for the operation, if it allocated from a mempool.

If Crypto operations are allocated from a Crypto operation mempool, see next section, there is also the ability to allocate private memory with the operation for applications purposes.

Application software is responsible for specifying all the operation specific fields in the rte_crypto_op structure which are then used by the Crypto PMD to process the requested operation.

18.4.5. Operation Management and Allocation

The cryptodev library provides an API set for managing Crypto operations which utilize the Mempool Library to allocate operation buffers. Therefore, it ensures that the crypto operation is interleaved optimally across the channels and ranks for optimal processing. A rte_crypto_op contains a field indicating the pool that it originated from. When calling rte_crypto_op_free(op), the operation returns to its original pool.

extern struct rte_mempool *
rte_crypto_op_pool_create(const char *name, enum rte_crypto_op_type type,
                          unsigned nb_elts, unsigned cache_size, uint16_t priv_size,
                          int socket_id);

During pool creation rte_crypto_op_init() is called as a constructor to initialize each Crypto operation which subsequently calls __rte_crypto_op_reset() to configure any operation type specific fields based on the type parameter.

rte_crypto_op_alloc() and rte_crypto_op_bulk_alloc() are used to allocate Crypto operations of a specific type from a given Crypto operation mempool. __rte_crypto_op_reset() is called on each operation before being returned to allocate to a user so the operation is always in a good known state before use by the application.

struct rte_crypto_op *rte_crypto_op_alloc(struct rte_mempool *mempool,
                                          enum rte_crypto_op_type type)

unsigned rte_crypto_op_bulk_alloc(struct rte_mempool *mempool,
                                  enum rte_crypto_op_type type,
                                  struct rte_crypto_op **ops, uint16_t nb_ops)

rte_crypto_op_free() is called by the application to return an operation to its allocating pool.

void rte_crypto_op_free(struct rte_crypto_op *op)

18.5. Symmetric Cryptography Support

The cryptodev library currently provides support for the following symmetric Crypto operations; cipher, authentication, including chaining of these operations, as well as also supporting AEAD operations.

18.5.1. Session and Session Management

Sessions are used in symmetric cryptographic processing to store the immutable data defined in a cryptographic transform which is used in the operation processing of a packet flow. Sessions are used to manage information such as expand cipher keys and HMAC IPADs and OPADs, which need to be calculated for a particular Crypto operation, but are immutable on a packet to packet basis for a flow. Crypto sessions cache this immutable data in a optimal way for the underlying PMD and this allows further acceleration of the offload of Crypto workloads.

The Crypto device framework provides APIs to create session mempool and allocate and initialize sessions for crypto devices, where sessions are mempool objects. The application has to use rte_cryptodev_sym_session_pool_create() to create the session header mempool that creates a mempool with proper element size automatically and stores necessary information for safely accessing the session in the mempool’s private data field.

To create a mempool for storing session private data, the application has two options. The first is to create another mempool with elt size equal to or bigger than the maximum session private data size of all crypto devices that will share the same session header. The creation of the mempool shall use the traditional rte_mempool_create() with the correct elt_size. The other option is to change the elt_size parameter in rte_cryptodev_sym_session_pool_create() to the correct value. The first option is more complex to implement but may result in better memory usage as a session header normally takes smaller memory footprint as the session private data.

Once the session mempools have been created, rte_cryptodev_sym_session_create() is used to allocate an uninitialized session from the given mempool. The session then must be initialized using rte_cryptodev_sym_session_init() for each of the required crypto devices. A symmetric transform chain is used to specify the operation and its parameters. See the section below for details on transforms.

When a session is no longer used, user must call rte_cryptodev_sym_session_clear() for each of the crypto devices that are using the session, to free all driver private session data. Once this is done, session should be freed using rte_cryptodev_sym_session_free which returns them to their mempool.

18.5.2. Transforms and Transform Chaining

Symmetric Crypto transforms (rte_crypto_sym_xform) are the mechanism used to specify the details of the Crypto operation. For chaining of symmetric operations such as cipher encrypt and authentication generate, the next pointer allows transform to be chained together. Crypto devices which support chaining must publish the chaining of symmetric Crypto operations feature flag. Allocation of the xform structure is in the application domain. To allow future API extensions in a backwardly compatible manner, e.g. addition of a new parameter, the application should zero the full xform struct before populating it.

Currently there are three transforms types cipher, authentication and AEAD. Also it is important to note that the order in which the transforms are passed indicates the order of the chaining.

struct rte_crypto_sym_xform {
    struct rte_crypto_sym_xform *next;
    /**< next xform in chain */
    enum rte_crypto_sym_xform_type type;
    /**< xform type */
    union {
        struct rte_crypto_auth_xform auth;
        /**< Authentication / hash xform */
        struct rte_crypto_cipher_xform cipher;
        /**< Cipher xform */
        struct rte_crypto_aead_xform aead;
        /**< AEAD xform */
    };
};

The API does not place a limit on the number of transforms that can be chained together but this will be limited by the underlying Crypto device poll mode driver which is processing the operation.

18.5.3. Symmetric Operations

The symmetric Crypto operation structure contains all the mutable data relating to performing symmetric cryptographic processing on a referenced mbuf data buffer. It is used for either cipher, authentication, AEAD and chained operations.

As a minimum the symmetric operation must have a source data buffer (m_src), a valid session (or transform chain if in session-less mode) and the minimum authentication/ cipher/ AEAD parameters required depending on the type of operation specified in the session or the transform chain.

struct rte_crypto_sym_op {
    struct rte_mbuf *m_src;
    struct rte_mbuf *m_dst;

    union {
        struct rte_cryptodev_sym_session *session;
        /**< Handle for the initialised session context */
        struct rte_crypto_sym_xform *xform;
        /**< Session-less API Crypto operation parameters */
    };

    union {
        struct {
            struct {
                uint32_t offset;
                uint32_t length;
            } data; /**< Data offsets and length for AEAD */

            struct {
                uint8_t *data;
                rte_iova_t phys_addr;
            } digest; /**< Digest parameters */

            struct {
                uint8_t *data;
                rte_iova_t phys_addr;
            } aad;
            /**< Additional authentication parameters */
        } aead;

        struct {
            struct {
                struct {
                    uint32_t offset;
                    uint32_t length;
                } data; /**< Data offsets and length for ciphering */
            } cipher;

            struct {
                struct {
                    uint32_t offset;
                    uint32_t length;
                } data;
                /**< Data offsets and length for authentication */

                struct {
                    uint8_t *data;
                    rte_iova_t phys_addr;
                } digest; /**< Digest parameters */
            } auth;
        };
    };
};

18.6. Synchronous mode

Some cryptodevs support synchronous mode alongside with a standard asynchronous mode. In that case operations are performed directly when calling rte_cryptodev_sym_cpu_crypto_process method instead of enqueuing and dequeuing an operation before. This mode of operation allows cryptodevs which utilize CPU cryptographic acceleration to have significant performance boost comparing to standard asynchronous approach. Cryptodevs supporting synchronous mode have RTE_CRYPTODEV_FF_SYM_CPU_CRYPTO feature flag set.

To perform a synchronous operation a call to rte_cryptodev_sym_cpu_crypto_process has to be made with vectorized operation descriptor (struct rte_crypto_sym_vec) containing:

• num - number of operations to perform,
• pointer to an array of size num containing a scatter-gather list descriptors of performed operations (struct rte_crypto_sgl). Each instance of struct rte_crypto_sgl consists of a number of segments and a pointer to an array of segment descriptors struct rte_crypto_vec;
• pointers to arrays of size num containing IV, AAD and digest information in the cpu_crypto sub-structure,
• pointer to an array of size num where status information will be stored for each operation.

Function returns a number of successfully completed operations and sets appropriate status number for each operation in the status array provided as a call argument. Status different than zero must be treated as error.

For more details, e.g. how to convert an mbuf to an SGL, please refer to an example usage in the IPsec library implementation.

18.6.1. Cryptodev Raw Data-path APIs

The Crypto Raw data-path APIs are a set of APIs designed to enable external libraries/applications to leverage the cryptographic processing provided by DPDK crypto PMDs through the cryptodev API but in a manner that is not dependent on native DPDK data structures (eg. rte_mbuf, rte_crypto_op, … etc) in their data-path implementation.

The raw data-path APIs have the following advantages:

• External data structure friendly design. The new APIs uses the operation descriptor struct rte_crypto_sym_vec that supports raw data pointer and IOVA addresses as input. Moreover, the APIs does not require the user to allocate the descriptor from mempool, nor requiring mbufs to describe input data’s virtual and IOVA addresses. All these features made the translation from user’s own data structure into the descriptor easier and more efficient.
• Flexible enqueue and dequeue operation. The raw data-path APIs gives the user more control to the enqueue and dequeue operations, including the capability of precious enqueue/dequeue count, abandoning enqueue or dequeue at any time, and operation status translation and set on the fly.

Cryptodev PMDs which support the raw data-path APIs will have RTE_CRYPTODEV_FF_SYM_RAW_DP feature flag presented. To use this feature, the user shall create a local struct rte_crypto_raw_dp_ctx buffer and extend to at least the length returned by rte_cryptodev_get_raw_dp_ctx_size function call. The created buffer is then initialized using rte_cryptodev_configure_raw_dp_ctx function with the is_update parameter as 0. The library and the crypto device driver will then set the buffer and attach either the cryptodev sym session, the rte_security session, or the cryptodev xform for session-less operation into the ctx buffer, and set the corresponding enqueue and dequeue function handlers based on the algorithm information stored in the session or xform. When the is_update parameter passed into rte_cryptodev_configure_raw_dp_ctx is 1, the driver will not initialize the buffer but only update the session or xform and the function handlers accordingly.

After the struct rte_crypto_raw_dp_ctx buffer is initialized, it is now ready for enqueue and dequeue operation. There are two different enqueue functions: rte_cryptodev_raw_enqueue to enqueue single raw data operation, and rte_cryptodev_raw_enqueue_burst to enqueue a descriptor with multiple operations. In case of the application uses similar approach to struct rte_crypto_sym_vec to manage its data burst but with different data structure, using the rte_cryptodev_raw_enqueue_burst function may be less efficient as this is a situation where the application has to loop over all crypto operations to assemble the struct rte_crypto_sym_vec descriptor from its own data structure, and then the driver will loop over them again to translate every operation in the descriptor to the driver’s specific queue data. The rte_cryptodev_raw_enqueue should be used to save one loop for each data burst instead.

The rte_cryptodev_raw_enqueue and rte_cryptodev_raw_enqueue_burst functions will return or set the enqueue status. rte_cryptodev_raw_enqueue will return the status directly, rte_cryptodev_raw_enqueue_burst will return the number of operations enqueued or stored (explained as follows) and set the enqueue_status buffer provided by the user. The possible enqueue status values are:

• 1: the operation(s) is/are enqueued successfully.
• 0: the operation(s) is/are cached successfully in the crypto device queue but is not actually enqueued. The user shall call rte_cryptodev_raw_enqueue_done function after the expected operations are stored. The crypto device will then start enqueuing all of them at once.
• The negative integer: error occurred during enqueue.

Calling rte_cryptodev_configure_raw_dp_ctx with the parameter is_update set as 0 twice without the enqueue function returning or setting enqueue status to 1 or rte_cryptodev_raw_enqueue_done function being called in between will invalidate any operation stored in the device queue but not enqueued. This feature is useful when the user wants to abandon partially enqueued operations for a failed enqueue burst operation and try enqueuing in a whole later.

Similar as enqueue, there are two dequeue functions: rte_cryptodev_raw_dequeue for dequeuing single operation, and rte_cryptodev_raw_dequeue_burst for dequeuing a burst of operations (e.g. all operations in a struct rte_crypto_sym_vec descriptor). The rte_cryptodev_raw_dequeue_burst function allows the user to provide callback functions to retrieve dequeue count from the enqueued user data and write the expected status value to the user data on the fly. The dequeue functions also set the dequeue status:

• 1: the operation(s) is/are dequeued successfully.
• 0: the operation(s) is/are completed but is not actually dequeued (hence still kept in the device queue). The user shall call the rte_cryptodev_raw_dequeue_done function after the expected number of operations (e.g. all operations in a descriptor) are dequeued. The crypto device driver will then free them from the queue at once.
• The negative integer: error occurred during dequeue.

Calling rte_cryptodev_configure_raw_dp_ctx with the parameter is_update set as 0 twice without the dequeue functions execution changed dequeue_status to 1 or rte_cryptodev_raw_dequeue_done function being called in between will revert the crypto device queue’s dequeue effort to the moment when the struct rte_crypto_raw_dp_ctx buffer is initialized. This feature is useful when the user wants to abandon partially dequeued data and try dequeuing again later in a whole.

There are a few limitations to the raw data path APIs:

• Only support in-place operations.
• APIs are NOT thread-safe.
• CANNOT mix the raw data-path API’s enqueue with rte_cryptodev_enqueue_burst, or vice versa.

See DPDK API Reference for details on each API definitions.

18.7. Sample code

There are various sample applications that show how to use the cryptodev library, such as the L2fwd with Crypto sample application (L2fwd-crypto) and the IPsec Security Gateway application (ipsec-secgw).

While these applications demonstrate how an application can be created to perform generic crypto operation, the required complexity hides the basic steps of how to use the cryptodev APIs.

The following sample code shows the basic steps to encrypt several buffers with AES-CBC (although performing other crypto operations is similar), using one of the crypto PMDs available in DPDK.

/*
 * Simple example to encrypt several buffers with AES-CBC using
 * the Cryptodev APIs.
 */

#define MAX_SESSIONS         1024
#define NUM_MBUFS            1024
#define POOL_CACHE_SIZE      128
#define BURST_SIZE           32
#define BUFFER_SIZE          1024
#define AES_CBC_IV_LENGTH    16
#define AES_CBC_KEY_LENGTH   16
#define IV_OFFSET            (sizeof(struct rte_crypto_op) + \
                             sizeof(struct rte_crypto_sym_op))

struct rte_mempool *mbuf_pool, *crypto_op_pool;
struct rte_mempool *session_pool, *session_priv_pool;
unsigned int session_size;
int ret;

/* Initialize EAL. */
ret = rte_eal_init(argc, argv);
if (ret < 0)
    rte_exit(EXIT_FAILURE, "Invalid EAL arguments\n");

uint8_t socket_id = rte_socket_id();

/* Create the mbuf pool. */
mbuf_pool = rte_pktmbuf_pool_create("mbuf_pool",
                                NUM_MBUFS,
                                POOL_CACHE_SIZE,
                                0,
                                RTE_MBUF_DEFAULT_BUF_SIZE,
                                socket_id);
if (mbuf_pool == NULL)
    rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");

/*
 * The IV is always placed after the crypto operation,
 * so some private data is required to be reserved.
 */
unsigned int crypto_op_private_data = AES_CBC_IV_LENGTH;

/* Create crypto operation pool. */
crypto_op_pool = rte_crypto_op_pool_create("crypto_op_pool",
                                        RTE_CRYPTO_OP_TYPE_SYMMETRIC,
                                        NUM_MBUFS,
                                        POOL_CACHE_SIZE,
                                        crypto_op_private_data,
                                        socket_id);
if (crypto_op_pool == NULL)
    rte_exit(EXIT_FAILURE, "Cannot create crypto op pool\n");

/* Create the virtual crypto device. */
char args[128];
const char *crypto_name = "crypto_aesni_mb0";
snprintf(args, sizeof(args), "socket_id=%d", socket_id);
ret = rte_vdev_init(crypto_name, args);
if (ret != 0)
    rte_exit(EXIT_FAILURE, "Cannot create virtual device");

uint8_t cdev_id = rte_cryptodev_get_dev_id(crypto_name);

/* Get private session data size. */
session_size = rte_cryptodev_sym_get_private_session_size(cdev_id);

#ifdef USE_TWO_MEMPOOLS
/* Create session mempool for the session header. */
session_pool = rte_cryptodev_sym_session_pool_create("session_pool",
                                MAX_SESSIONS,
                                0,
                                POOL_CACHE_SIZE,
                                0,
                                socket_id);

/*
 * Create session private data mempool for the
 * private session data for the crypto device.
 */
session_priv_pool = rte_mempool_create("session_pool",
                                MAX_SESSIONS,
                                session_size,
                                POOL_CACHE_SIZE,
                                0, NULL, NULL, NULL,
                                NULL, socket_id,
                                0);

#else
/* Use of the same mempool for session header and private data */
    session_pool = rte_cryptodev_sym_session_pool_create("session_pool",
                                MAX_SESSIONS * 2,
                                session_size,
                                POOL_CACHE_SIZE,
                                0,
                                socket_id);

    session_priv_pool = session_pool;

#endif

/* Configure the crypto device. */
struct rte_cryptodev_config conf = {
    .nb_queue_pairs = 1,
    .socket_id = socket_id
};

struct rte_cryptodev_qp_conf qp_conf = {
    .nb_descriptors = 2048,
    .mp_session = session_pool,
    .mp_session_private = session_priv_pool
};

if (rte_cryptodev_configure(cdev_id, &conf) < 0)
    rte_exit(EXIT_FAILURE, "Failed to configure cryptodev %u", cdev_id);

if (rte_cryptodev_queue_pair_setup(cdev_id, 0, &qp_conf, socket_id) < 0)
    rte_exit(EXIT_FAILURE, "Failed to setup queue pair\n");

if (rte_cryptodev_start(cdev_id) < 0)
    rte_exit(EXIT_FAILURE, "Failed to start device\n");

/* Create the crypto transform. */
uint8_t cipher_key[16] = {0};
struct rte_crypto_sym_xform cipher_xform = {
    .next = NULL,
    .type = RTE_CRYPTO_SYM_XFORM_CIPHER,
    .cipher = {
        .op = RTE_CRYPTO_CIPHER_OP_ENCRYPT,
        .algo = RTE_CRYPTO_CIPHER_AES_CBC,
        .key = {
            .data = cipher_key,
            .length = AES_CBC_KEY_LENGTH
        },
        .iv = {
            .offset = IV_OFFSET,
            .length = AES_CBC_IV_LENGTH
        }
    }
};

/* Create crypto session and initialize it for the crypto device. */
struct rte_cryptodev_sym_session *session;
session = rte_cryptodev_sym_session_create(session_pool);
if (session == NULL)
    rte_exit(EXIT_FAILURE, "Session could not be created\n");

if (rte_cryptodev_sym_session_init(cdev_id, session,
                &cipher_xform, session_priv_pool) < 0)
    rte_exit(EXIT_FAILURE, "Session could not be initialized "
                "for the crypto device\n");

/* Get a burst of crypto operations. */
struct rte_crypto_op *crypto_ops[BURST_SIZE];
if (rte_crypto_op_bulk_alloc(crypto_op_pool,
                        RTE_CRYPTO_OP_TYPE_SYMMETRIC,
                        crypto_ops, BURST_SIZE) == 0)
    rte_exit(EXIT_FAILURE, "Not enough crypto operations available\n");

/* Get a burst of mbufs. */
struct rte_mbuf *mbufs[BURST_SIZE];
if (rte_pktmbuf_alloc_bulk(mbuf_pool, mbufs, BURST_SIZE) < 0)
    rte_exit(EXIT_FAILURE, "Not enough mbufs available");

/* Initialize the mbufs and append them to the crypto operations. */
unsigned int i;
for (i = 0; i < BURST_SIZE; i++) {
    if (rte_pktmbuf_append(mbufs[i], BUFFER_SIZE) == NULL)
        rte_exit(EXIT_FAILURE, "Not enough room in the mbuf\n");
    crypto_ops[i]->sym->m_src = mbufs[i];
}

/* Set up the crypto operations. */
for (i = 0; i < BURST_SIZE; i++) {
    struct rte_crypto_op *op = crypto_ops[i];
    /* Modify bytes of the IV at the end of the crypto operation */
    uint8_t *iv_ptr = rte_crypto_op_ctod_offset(op, uint8_t *,
                                            IV_OFFSET);

    generate_random_bytes(iv_ptr, AES_CBC_IV_LENGTH);

    op->sym->cipher.data.offset = 0;
    op->sym->cipher.data.length = BUFFER_SIZE;

    /* Attach the crypto session to the operation */
    rte_crypto_op_attach_sym_session(op, session);
}

/* Enqueue the crypto operations in the crypto device. */
uint16_t num_enqueued_ops = rte_cryptodev_enqueue_burst(cdev_id, 0,
                                        crypto_ops, BURST_SIZE);

/*
 * Dequeue the crypto operations until all the operations
 * are processed in the crypto device.
 */
uint16_t num_dequeued_ops, total_num_dequeued_ops = 0;
do {
    struct rte_crypto_op *dequeued_ops[BURST_SIZE];
    num_dequeued_ops = rte_cryptodev_dequeue_burst(cdev_id, 0,
                                    dequeued_ops, BURST_SIZE);
    total_num_dequeued_ops += num_dequeued_ops;

    /* Check if operation was processed successfully */
    for (i = 0; i < num_dequeued_ops; i++) {
        if (dequeued_ops[i]->status != RTE_CRYPTO_OP_STATUS_SUCCESS)
            rte_exit(EXIT_FAILURE,
                    "Some operations were not processed correctly");
    }

    rte_mempool_put_bulk(crypto_op_pool, (void **)dequeued_ops,
                                        num_dequeued_ops);
} while (total_num_dequeued_ops < num_enqueued_ops);

18.8. Asymmetric Cryptography

The cryptodev library currently provides support for the following asymmetric Crypto operations; RSA, Modular exponentiation and inversion, Diffie-Hellman and Elliptic Curve Diffie-Hellman public and/or private key generation and shared secret compute, DSA Signature generation and verification.

18.8.1. Session and Session Management

Sessions are used in asymmetric cryptographic processing to store the immutable data defined in asymmetric cryptographic transform which is further used in the operation processing. Sessions typically stores information, such as, public and private key information or domain params or prime modulus data i.e. immutable across data sets. Crypto sessions cache this immutable data in a optimal way for the underlying PMD and this allows further acceleration of the offload of Crypto workloads.

Like symmetric, the Crypto device framework provides APIs to allocate and initialize asymmetric sessions for crypto devices, where sessions are mempool objects. It is the application’s responsibility to create and manage the session mempools. Application using both symmetric and asymmetric sessions should allocate and maintain different sessions pools for each type.

An application can use rte_cryptodev_asym_session_pool_create() to create a mempool with a specified number of elements. The element size will allow for the session header, and the max private session size. The max private session size is chosen based on available crypto devices, the biggest private session size is used. This means any of those devices can be used, and the mempool element will have available space for its private session data.

Once the session mempools have been created, rte_cryptodev_asym_session_create() is used to allocate and initialize an asymmetric session from the given mempool. An asymmetric transform chain is used to specify the operation and its parameters. See the section below for details on transforms.

When a session is no longer used, user must call rte_cryptodev_asym_session_clear() for each of the crypto devices that are using the session, to free all driver private asymmetric session data. Once this is done, session should be freed using rte_cryptodev_asym_session_free() which returns them to their mempool.

18.8.2. Asymmetric Sessionless Support

Asymmetric crypto framework supports session-less operations as well.

Fields that should be set by user are:

Member xform of struct rte_crypto_asym_op should point to the user created rte_crypto_asym_xform. Note that rte_crypto_asym_xform should be immutable for the lifetime of associated crypto_op.

Member sess_type of rte_crypto_op should also be set to RTE_CRYPTO_OP_SESSIONLESS.

18.8.3. Transforms and Transform Chaining

Asymmetric Crypto transforms (rte_crypto_asym_xform) are the mechanism used to specify the details of the asymmetric Crypto operation. Next pointer within xform allows transform to be chained together. Also it is important to note that the order in which the transforms are passed indicates the order of the chaining. Allocation of the xform structure is in the application domain. To allow future API extensions in a backwardly compatible manner, e.g. addition of a new parameter, the application should zero the full xform struct before populating it.

Not all asymmetric crypto xforms are supported for chaining. Currently supported asymmetric crypto chaining is Diffie-Hellman private key generation followed by public generation. Also, currently API does not support chaining of symmetric and asymmetric crypto xforms.

Each xform defines specific asymmetric crypto algo. Currently supported are: * RSA * Modular operations (Exponentiation and Inverse) * Diffie-Hellman * DSA * Elliptic Curve Diffie-Hellman * None - special case where PMD may support a passthrough mode. More for diagnostic purpose

See DPDK API Reference for details on each rte_crypto_xxx_xform struct

18.8.4. Asymmetric Operations

The asymmetric Crypto operation structure contains all the mutable data relating to asymmetric cryptographic processing on an input data buffer. It uses either RSA, Modular, Diffie-Hellman or DSA operations depending upon session it is attached to.

Every operation must carry a valid session handle which further carries information on xform or xform-chain to be performed on op. Every xform type defines its own set of operational params in their respective rte_crypto_xxx_op_param struct. Depending on xform information within session, PMD picks up and process respective op_param struct. Unlike symmetric, asymmetric operations do not use mbufs for input/output. They operate on data buffer of type rte_crypto_param.

See DPDK API Reference for details on each rte_crypto_xxx_op_param struct

18.8.5. Private user data

Similar to symmetric above, asymmetric also has a set and get API that provides a mechanism for an application to store and retrieve the private user data information stored along with the crypto session.

int rte_cryptodev_asym_session_set_user_data(void *sess,
        void *data, uint16_t size);

void * rte_cryptodev_asym_session_get_user_data(void *sess);

Please note the size passed to set API cannot be bigger than the predefined user_data_sz when creating the session mempool, otherwise the function will return an error. Also when user_data_sz was defined as 0 when creating the session mempool, the get API will always return NULL.

18.9. Asymmetric crypto Sample code

There’s a unit test application test_cryptodev_asym.c inside unit test framework that show how to setup and process asymmetric operations using cryptodev library.

The following code samples are taken from the test application mentioned above, and show basic steps to compute modular exponentiation using an openssl PMD available in DPDK (performing other crypto operations is similar except change to respective op and xform setup).

Note

The following code snippets are taken from multiple functions, so variable names may differ slightly between sections.

Configure the virtual device, queue pairs, crypto op pool and session mempool.

ts_params->op_mpool = rte_crypto_op_pool_create(
		"CRYPTO_ASYM_OP_POOL",
		RTE_CRYPTO_OP_TYPE_ASYMMETRIC,
		TEST_NUM_BUFS, 0,
		0,
		rte_socket_id());
if (ts_params->op_mpool == NULL) {
	RTE_LOG(ERR, USER1, "Can't create ASYM_CRYPTO_OP_POOL\n");
	return TEST_FAILED;
}

/* Create an OPENSSL device if required */
if (gbl_driver_id == rte_cryptodev_driver_id_get(
		RTE_STR(CRYPTODEV_NAME_OPENSSL_PMD))) {
	nb_devs = rte_cryptodev_device_count_by_driver(
			rte_cryptodev_driver_id_get(
			RTE_STR(CRYPTODEV_NAME_OPENSSL_PMD)));
	if (nb_devs < 1) {
		ret = rte_vdev_init(
			RTE_STR(CRYPTODEV_NAME_OPENSSL_PMD),
			NULL);

		TEST_ASSERT(ret == 0, "Failed to create "
			"instance of pmd : %s",
			RTE_STR(CRYPTODEV_NAME_OPENSSL_PMD));
	}
}

/* Get list of valid crypto devs */
nb_devs = rte_cryptodev_devices_get(
			rte_cryptodev_driver_name_get(gbl_driver_id),
			valid_devs, RTE_CRYPTO_MAX_DEVS);
if (nb_devs < 1) {
	RTE_LOG(ERR, USER1, "No crypto devices found?\n");
	return TEST_FAILED;
}

/*
 * Get first valid asymmetric device found in test suite param and
 * break
 */
for (i = 0; i < nb_devs ; i++) {
	rte_cryptodev_info_get(valid_devs[i], &info);
	if (info.feature_flags & RTE_CRYPTODEV_FF_ASYMMETRIC_CRYPTO) {
		dev_id = ts_params->valid_devs[0] = valid_devs[i];
		break;
	}
}

if (dev_id == -1) {
	RTE_LOG(ERR, USER1, "Device doesn't support asymmetric. "
		"Test skipped.\n");
	return TEST_FAILED;
}

/* Set valid device count */
ts_params->valid_dev_count = nb_devs;

/* configure device with num qp */
ts_params->conf.nb_queue_pairs = info.max_nb_queue_pairs;
ts_params->conf.socket_id = SOCKET_ID_ANY;
ts_params->conf.ff_disable = RTE_CRYPTODEV_FF_SECURITY |
		RTE_CRYPTODEV_FF_SYMMETRIC_CRYPTO;
TEST_ASSERT_SUCCESS(rte_cryptodev_configure(dev_id,
		&ts_params->conf),
		"Failed to configure cryptodev %u with %u qps",
		dev_id, ts_params->conf.nb_queue_pairs);

/* configure qp */
ts_params->qp_conf.nb_descriptors = DEFAULT_NUM_OPS_INFLIGHT;
ts_params->qp_conf.mp_session = ts_params->session_mpool;
for (qp_id = 0; qp_id < info.max_nb_queue_pairs; qp_id++) {
	TEST_ASSERT_SUCCESS(rte_cryptodev_queue_pair_setup(
		dev_id, qp_id, &ts_params->qp_conf,
		rte_cryptodev_socket_id(dev_id)),
		"Failed to setup queue pair %u on cryptodev %u ASYM",
		qp_id, dev_id);
}

ts_params->session_mpool = rte_cryptodev_asym_session_pool_create(
		"test_asym_sess_mp", TEST_NUM_SESSIONS, 0, 0,
		SOCKET_ID_ANY);

TEST_ASSERT_NOT_NULL(ts_params->session_mpool,
		"session mempool allocation failed");

Create MODEX data vectors.

uint8_t mod_p[] = {
	0x00, 0xb3, 0xa1, 0xaf, 0xb7, 0x13, 0x08, 0x00,
	0x0a, 0x35, 0xdc, 0x2b, 0x20, 0x8d, 0xa1, 0xb5,
	0xce, 0x47, 0x8a, 0xc3, 0x80, 0xf4, 0x7d, 0x4a,
	0xa2, 0x62, 0xfd, 0x61, 0x7f, 0xb5, 0xa8, 0xde,
	0x0a, 0x17, 0x97, 0xa0, 0xbf, 0xdf, 0x56, 0x5a,
	0x3d, 0x51, 0x56, 0x4f, 0x70, 0x70, 0x3f, 0x63,
	0x6a, 0x44, 0x5b, 0xad, 0x84, 0x0d, 0x3f, 0x27,
	0x6e, 0x3b, 0x34, 0x91, 0x60, 0x14, 0xb9, 0xaa,
	0x72, 0xfd, 0xa3, 0x64, 0xd2, 0x03, 0xa7, 0x53,
	0x87, 0x9e, 0x88, 0x0b, 0xc1, 0x14, 0x93, 0x1a,
	0x62, 0xff, 0xb1, 0x5d, 0x74, 0xcd, 0x59, 0x63,
	0x18, 0x11, 0x3d, 0x4f, 0xba, 0x75, 0xd4, 0x33,
	0x4e, 0x23, 0x6b, 0x7b, 0x57, 0x44, 0xe1, 0xd3,
	0x03, 0x13, 0xa6, 0xf0, 0x8b, 0x60, 0xb0, 0x9e,
	0xee, 0x75, 0x08, 0x9d, 0x71, 0x63, 0x13, 0xcb,
	0xa6, 0x81, 0x92, 0x14, 0x03, 0x22, 0x2d, 0xde,
	0x55
};

uint8_t mod_e[] = {0x01, 0x00, 0x01};

Setup crypto xform to do modular exponentiation using data vectors.

struct rte_crypto_asym_xform modex_xform = {
	.next = NULL,
	.xform_type = RTE_CRYPTO_ASYM_XFORM_MODEX,
	.modex = {
		.modulus = {
			.data = mod_p,
			.length = sizeof(mod_p)
		},
		.exponent = {
			.data = mod_e,
			.length = sizeof(mod_e)
		}
	}
};

Generate crypto op, create and attach a session, then process packets.

op = rte_crypto_op_alloc(op_mpool, RTE_CRYPTO_OP_TYPE_ASYMMETRIC);
if (!op) {
	RTE_LOG(ERR, USER1,
		"line %u FAILED: %s",
		__LINE__, "Failed to allocate asymmetric crypto "
		"operation struct");
	status = TEST_FAILED;
	goto error_exit;
}

ret = rte_cryptodev_asym_session_create(dev_id, &modex_xform, sess_mpool, &sess);
if (ret < 0) {
	RTE_LOG(ERR, USER1,
			 "line %u "
			"FAILED: %s", __LINE__,
			"Session creation failed");
	status = (ret == -ENOTSUP) ? TEST_SKIPPED : TEST_FAILED;
	goto error_exit;
}

asym_op = op->asym;
memcpy(input, base, sizeof(base));
asym_op->modex.base.data = input;
asym_op->modex.base.length = sizeof(base);
asym_op->modex.result.data = result;
asym_op->modex.result.length = sizeof(result);
/* attach asymmetric crypto session to crypto operations */
rte_crypto_op_attach_asym_session(op, sess);

RTE_LOG(DEBUG, USER1, "Process ASYM operation");
/* Process crypto operation */
if (rte_cryptodev_enqueue_burst(dev_id, 0, &op, 1) != 1) {
	RTE_LOG(ERR, USER1,
			"line %u FAILED: %s",
			__LINE__, "Error sending packet for operation");
	status = TEST_FAILED;
	goto error_exit;
}

while (rte_cryptodev_dequeue_burst(dev_id, 0, &result_op, 1) == 0)
	rte_pause();

if (result_op == NULL) {
	RTE_LOG(ERR, USER1,
			"line %u FAILED: %s",
			__LINE__, "Failed to process asym crypto op");
	status = TEST_FAILED;
	goto error_exit;
}

Note

The rte_cryptodev_asym_session struct is hidden from the application. The sess pointer used above is a void pointer.

18.9.1. Asymmetric Crypto Device API

The cryptodev Library API is described in the DPDK API Reference

18.10. Device Statistics

The Cryptodev library has support for displaying Crypto device information through the Telemetry interface. Telemetry commands that can be used are shown below.

1. Get the list of available Crypto devices by ID:

   --> /cryptodev/list
   {"/cryptodev/list": [0, 1, 2, 3]}
   

2. Get general information from a Crypto device:

   --> /cryptodev/info,0
   {"/cryptodev/info": {"device_name": "0000:1c:01.0_qat_sym",
   "max_nb_queue_pairs": 2}}
   

3. Get the statistics for a particular Crypto device:

   --> /cryptodev/stats,0
   {"/cryptodev/stats": {"enqueued_count": 0, "dequeued_count": 0,
   "enqueue_err_count": 0, "dequeue_err_count": 0}}
   

4. Get the capabilities of a particular Crypto device:

   --> /cryptodev/caps,0
   {"/cryptodev/caps": {"crypto_caps": [<array of serialized bytes of
   capabilities>], "crypto_caps_n": <number of capabilities>}}
   

For more information on how to use the Telemetry interface, see the DPDK Telemetry User Guide.