Ethernet Programming Guide

NVIDIA DOCA Ethernet Programming Guide

This guide provides an overview and configuration instructions for the DOCA ETH API.

The DOCA ETH library comprises two APIs that represent two DOCA objects, namely DOCA_ETH_RXQ and DOCA_ETH_TXQ.

The control path API is handled on the host CPU side by the library. DOCA_ETH_RXQ/DOCA_ETH_TXQ are configured on the CPU and then exported to the GPU which performs its data path.

DOCA_ETH_RXQ offers an API to receive packets on an RX queue. The doca_eth_rxq object allows developers to receive Ethernet packets in CPU/GPU memory that they have allocated beforehand (Ethernet receive packets buffer). The library collects the user configuration, creates a receive queue object on the GPU memory (using the DOCA_GPU sub-device), and coordinates with the network card (NIC) to receive packets directly into GPU memory.

DOCA_ETH_TXQ provides an API to send packets on a TX queue. The library collects the user configuration and creates a send queue object on the GPU memory (using the DOCA_GPU sub-device) and exports its configuration to the GPU, enabling developers to send packets on this queue from the GPU side.

DOCA Ethernet library (Tx/Rx) is supported on the DPU control path and GPU as data path (see GPUNetIO library).

The machine must meet the following prerequisites:

• DOCA version 2.0.2 or greater
• BlueField software 4.0.2 or greater
• BlueField-3 firmware 32.37.1000 or greater
• BlueField-2 firmware 24.37.1000 or greater

1. DOCA ETH provides a set of CPU functions to:
   1. Create a DOCA ETH context.
   2. Configure DOCA ETH context.
      1. Configure RX queue size.
      2. Configure TX queue size.
      3. Set TX checksum offloads.
   3. Get a GPU handle of the DOCA_GPU_ETH object.
   4. Destroy a DOCA ETH context.

2. The DOCA ETH context is configured on the CPU and then exported to the GPU:

   

3. Expected flow (doca_eth_rxq)
   1. Create a DOCA_GPU device handler.
   2. Create a doca_eth_rxq and configure its parameters (type, num_packets, packet_size, packet_buffer).
   3. Add a device to the context.
   4. Set the data path of the context to GPU.

   5. Start the context.

      

• DOCA ETH relies on the doca_gpunetio library to use GPU internal operations
• DOCA ETH relies on the dpdk_bridge library to allow interoperability between the library, dpdk, and doca_flow

• Data path on the CPU is not supported.
• RX/TX does not handle steering. Use DOCA Flow to do that.

To use DOCA_FLOW:

1. Select a device.
2. Probe the device.
   Note:

   Only one port can be probed for the device.

3. Obtain the DOCA ETH queue ID.
4. Create a DOCA Flow pipe.

This chapter provides a detailed description of the specific structures and operations related to the DOCA ETH control path API for general initialization, setup, and clean-up.

7.1. DOCA ETH RXQ

The doca_eth_rxq object allows querying device capabilities, setting object properties, creating and configuring an instance of doca_eth_rxq, and destroying it when no longer needed.

7.1.1. Querying Device Capabilities

Querying device capabilities provides information on the derived DOCA Ethernet limitations and enables users to set the properties of a doca_eth_rxq object accordingly.

The following subsections describe the functions which allow querying the device capabilities.

7.1.1.1. doca_eth_rxq_get_max_packet_size_supported()

This function queries the maximum packet size supported by the device. Any packet size bigger than this value is not accepted when trying to start the doca_eth_rxq object.

            

            
doca_error_t doca_eth_rxq_get_max_packet_size_supported(const struct doca_devinfo *devinfo, uint16_t *max_packet_size);
        

devinfo [in]

Pointer to a doca_devinfo instance.

max_packet_size [out]

Maximum packet size.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.1.2. doca_eth_rxq_get_type_supported()

This function checks if an RX queue type is supported by the device.

            

            
doca_error_t doca_eth_rxq_get_type_supported(const struct doca_devinfo *devinfo, enum doca_eth_rxq_type type, uint8_t *type_supported);
        

devinfo [in]

Pointer to a doca_devinfo instance.

type [in]

RX queue type (the values are documented in the header file).

type_supported [out]

Flag to indicate if the type is supported.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2. Creating and Configuring DOCA_ETH_RXQ

7.1.2.1. doca_eth_rxq_create()

This function creates an instance of doca_eth_rxq.

            

            
doca_error_t doca_eth_rxq_create(struct doca_eth_rxq **eth_rxq);
        

eth_rxq [out]

Pointer to the newly created doca_eth_rxq instance.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.2. doca_eth_rxq_destroy()

This function destroys a doca_eth_rxq instance.

            

            
doca_error_t doca_eth_rxq_destroy(struct doca_eth_rxq *eth_rxq);
        

eth_rxq [in]

Pointer to the doca_eth_rxq to be destroyed.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.3. doca_eth_rxq_set_num_packets()

This function sets the number of packets the RX queue can hold.

            

            
doca_error_t doca_eth_rxq_set_num_packets(struct doca_eth_rxq *eth_rxq, uint32_t num_packets);
        

eth_rxq [in]

Pointer to the doca_eth_rxq instance.

num_packets [in]

Maximum number of packets the queue can hold in the context.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.4. doca_eth_rxq_set_max_packet_size()

This function sets the maximum Ethernet packet size the RX queue can accommodate.

            

            
doca_error_t doca_eth_rxq_set_max_packet_size(struct doca_eth_rxq *eth_rxq, uint16_t max_pkt_sz);
        

eth_rxq [in]

Pointer to the doca_eth_rxq instance.

max_pkt_sz [in]

Maximum packet size the RX queue can handle in the context.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.5. doca_eth_rxq_set_type()

This function sets the RX queue type.

            

            
doca_error_t doca_eth_rxq_set_type(struct doca_eth_rxq *eth_rxq, enum doca_eth_rxq_type type);
        

eth_rxq [in]

Pointer to the doca_eth_rxq instance.

type [in]

Type of the RX queue. Possible values are documented in the header file.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.6. doca_eth_rxq_get_flow_queue_id()

This function retrieves the DPDK queue ID of the receive queue, which can be used in rte_flow or doca_flow.

            

            
doca_error_t doca_eth_rxq_get_flow_queue_id(struct doca_eth_rxq *eth_rxq, uint16_t *flow_queue_id);
        

eth_rxq [in]

Pointer to the doca_eth_rxq instance.

flow_queue_id [out]

Queue ID, which can be used in rte_flow or doca_flow.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.7. doca_eth_rxq_get_gpu_handle()

This function retrieves the GPU handle of a doca_eth_rxq instance.

The following is the expected flow:

1. Bind the context to a GPU device using doca_ctx_set_data_path_on_gpu().
2. Start the context using doca_ctx_start().
3. Call doca_eth_rxq_get_gpu_handle() to retrieve the gpu_handle.

            

            
doca_error_t doca_eth_rxq_get_gpu_handle(const struct doca_eth_rxq *eth_rxq, struct doca_gpu_eth_rxq **eth_rxq_ext);
        

eth_rxq [in]

Pointer to the doca_eth_rxq instance.

eth_rxq_ext [out]

Handle for the DOCA GPU eth_rxq.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.8. doca_eth_rxq_get_pkt_buffer_size()

This function retrieves the size for the Ethernet packet buffer of a doca_eth_rxq.

            

            
doca_error_t doca_eth_rxq_get_pkt_buffer_size(const struct doca_eth_rxq *eth_rxq, uint32_t *size);
        

eth_rxq [in]

Pointer to the doca_eth_rxq instance.

size [out]

Required size for the Ethernet packet buffer.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.1.2.9. doca_eth_rxq_set_pkt_buffer()

This function sets the Ethernet packet buffer of a doca_eth_rxq.

            

            
doca_error_t doca_eth_rxq_set_pkt_buffer(struct doca_eth_rxq *eth_rxq, struct doca_mmap *mmap, uint32_t offset, uint32_t size);
        

eth_rxq [in]

Pointer to the doca_eth_rxq instance.

mmap [in]

Mmap with the memrange for the Ethernet packet buffer.

size [in]

Size of the Ethernet packet buffer.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2. DOCA ETH TXQ

The doca_eth_txq object allows querying device capabilities, setting object properties, creating and configuring an instance of doca_eth_txq, and destroying it when no longer needed.

7.2.1. Querying Device Capabilities

Querying device capabilities provides users with information regarding the derived DOCA Eth limitations and enables them to set the properties of a doca_eth_txq object accordingly.

The following subsections describe the functions which allow querying the device capabilities.

7.2.1.1. doca_eth_txq_get_max_queue_size_supported()

This function queries the maximum queue size supported by the device. Any queue size bigger than this value is not accepted when trying to start the doca_eth_txq object.

            

            
doca_error_t doca_eth_txq_get_max_queue_size_supported(const struct doca_devinfo *devinfo, uint32_t *max_queue_size);
        

devinfo [in]

Pointer to a doca_devinfo instance.

max_queue_size [out]

Maximum queue size supported by the device.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.1.2. doca_eth_txq_get_type_supported()

This function checks if a TX queue type is supported by the device.

            

            
doca_error_t doca_eth_txq_get_type_supported(const struct doca_devinfo *devinfo, enum doca_eth_txq_type type, uint8_t *type_supported);
        

devinfo [in]

Pointer to a doca_devinfo instance.

type [in]

TX queue type.

type_supported [out]

Flag to indicate if the type is supported.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.1.3. doca_eth_txq_get_chksum_offload_supported()

This function checks if checksum offload is supported by the device.

            

            
doca_error_t doca_eth_txq_get_chksum_offload_supported(const struct doca_devinfo *devinfo, uint8_t *offload_supported);
        

devinfo [in]

Pointer to a doca_devinfo instance.

offload_supported [out]

Flag to indicate if checksum offload is supported.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.2. Creating and Configuring DOCA_ETH_TXQ

7.2.2.1. doca_eth_txq_create()

This function creates an instance of doca_eth_txq.

            

            
doca_error_t doca_eth_txq_create(struct doca_eth_txq **eth_txq);
        

eth_txq [out]

Pointer to the newly created doca_eth_txq instance.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.2.2. doca_eth_txq_destroy()

This function destroys a doca_eth_txq instance.

            

            
doca_error_t doca_eth_txq_destroy(struct doca_eth_txq *eth_txq);
        

eth_txq [in]

Pointer to the doca_eth_txq instance to destroy.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.2.3. doca_eth_txq_set_queue_size()

This function sets the size of the TX queue.

            

            
doca_error_t doca_eth_txq_set_queue_size(struct doca_eth_txq *eth_txq, uint32_t size);
        

eth_txq [in]

Pointer to the doca_eth_txq instance.

size [in]

TX queue size.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.2.4. doca_eth_txq_set_type()

This function sets the TX queue type.

            

            
doca_error_t doca_eth_txq_set_type(struct doca_eth_txq *eth_txq, enum doca_eth_txq_type type);
        

eth_txq [in]

Pointer to the doca_eth_txq instance.

type [in]

Type of the TX queue. Possible values are documented in the header file.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.2.5. doca_eth_txq_set_l4_chksum_offload()

This function sets offload for the calculation of TCP/UDP checksum (L4) on transmitted packets.

            

            
doca_error_t doca_eth_txq_set_l4_chksum_offload(struct doca_eth_txq *eth_txq);
        

eth_txq [in]

Pointer to the doca_eth_txq instance.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.2.6. doca_eth_txq_set_l3_chksum_offload()

This function sets offload for the calculation of IPv4 checksum (L3) on transmitted packets.

            

            
doca_error_t doca_eth_txq_set_l3_chksum_offload(struct doca_eth_txq *eth_txq);
        

eth_txq [in]

Pointer to the doca_eth_txq instance.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

7.2.2.7. doca_eth_txq_get_gpu_handle()

This function retrieves the GPU handle of a doca_eth_txq instance.

The following is the expected flow:

1. Bind the context to a GPU device using doca_ctx_set_data_path_on_gpu().
2. Start the context using doca_ctx_start().
3. Call doca_eth_txq_get_gpu_handle() to retrieve the gpu_handle.

            

            
doca_error_t doca_eth_txq_get_gpu_handle(const struct doca_eth_txq *eth_txq, struct doca_gpu_eth_txq **eth_txq_ext);
        

eth_txq [in]

Pointer to the doca_eth_txq instance.

eth_txq_ext [out]

Handle for the DOCA GPU eth_rxq.

Returns

doca_error_t value. DOCA_SUCCESS if successful or an error value upon failure. Possible error values are documented in the header file.

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