# Linux SockXdp - emllSockXdp

The Real-time Ethernet Driver SockXdp does not need the atemsys driver and uses already established Ethernet adapters, e.g. eth0, eth1, etc. It is strongly recommended to use a separate network adapter to connect EtherCAT® network adapters. If the main network adapter is used for both EtherCAT® network adapters and the local area network there may be a major impact on the local area network operation.

#### NOTE
Root privileges are required.

The parameters to the Real-time Ethernet Driver SockXdp are setup-specific. The function `CreateLinkParmsFromCmdLineSockXdp()` in [`EcSelectLinkLayer.cpp`](_downloads/bf62c71a4a7e317930818b9da4a9815c/EcSelectLinkLayer.cpp) demonstrates how to initialize the Real-time Ethernet Driver instance.

### struct EC_T_LINK_PARMS_SOCKXDP

### Public Members

### [EC_T_LINK_PARMS](emll_init.html.md#_CPPv415EC_T_LINK_PARMS) linkParms

Common link parameters. Signature must be set to EC_LINK_PARMS_SIGNATURE_SOCKXDP. 

### [EC_T_CHAR](api.html.md#_CPPv49EC_T_CHAR) szAdapterName[EC_SOCKXDP_ADAPTER_NAME_SIZE]

Native ETH device name, e.g. “eth0” (zero terminated) 

### [EC_T_WORD](api.html.md#_CPPv49EC_T_WORD) wQueueId

Used NIC Queue Id 

### [EC_T_XDP_MODE](#_CPPv413EC_T_XDP_MODE) eXdpMode

XDP mode 

### [EC_T_BOOL](api.html.md#_CPPv49EC_T_BOOL) bDisableForceBroadcast

Don’t change target MAC address to FF:FF:FF:FF:FF:FF 

### [EC_T_BOOL](api.html.md#_CPPv49EC_T_BOOL) bReplacePaddingWithNopCmd

Prevent adding Ethernet padding to work-around EtherCAT corruption bugs from native Linux driver(s) 

### enum EC_T_XDP_MODE

*Values:*

### enumerator eXDP_SKB_MODE

Generic XDP, XDP runs in the standard network stack. This is the fallback mode if native XDP is not supported 

### enumerator eXDP_DRV_MODE

Native XDP, Runs XDP directly in the NIC driver. This is the recommended mode for the best performance 

### enumerator eXDP_HW_MODE

Offloaded XDP, XDP programs are offloaded to the network card itself, running on the NIC firmware, not tested 

### enumerator eXDP_DRV_ZEROCOPY

Native XDP with ZEROCOPY 

## Linux System Requirements

To use the XDP Real-time Ethernet Driver the following system requirements need to be met:

- Your kernel have to support XDP, check if the following entry is activated in your `.config` file.
  : `CONFIG_XDP_SOCKETS=y`
    <br/>
    If it is not activated you need to rebuild your kernel with `CONFIG_XDP_SOCKETS`.

## Getting started

- Download libxdp Version 1.4.3 from [https://github.com/xdp-project/xdp-tools](https://github.com/xdp-project/xdp-tools) and install it.
- Download libbpf Version 1.5.0 from [https://github.com/libbpf/libbpf](https://github.com/libbpf/libbpf) and install it.
- Update the linux drivers of the NIC that would be used
- If the NIC  supports XDP, turn off xdp generic mode:
  : ```console
    $ ip link set dev eth0 xdpgeneric off
    ```
- If the NIC have multiple queue support, use one queue instead of multiple queues:
  : ```console
    $ ethtool -L eth0 combined 1
    ```