Network devices fall into the category of devices not appearing in the /dev directory (unlike block, input, or char devices). Therefore, like all of those kinds of devices, the NIC driver exposes a set of facilities in order to perform. The kernel exposes operations that can be performed on the network interfaces by means of the struct net_device_ops structure, which is a field of the struct net_device structure, representing the network device (dev->netdev_ops). The struct net_device_ops fields are described as follows:

struct net_device_ops { 
   int (*ndo_init)(struct net_device *dev); 
   void (*ndo_uninit)(struct net_device *dev); 
   int (*ndo_open)(struct net_device *dev); 
   int (*ndo_stop)(struct net_device *dev); 
   netdev_tx_t (*ndo_start_xmit) (struct sk_buff *skb, 
                              struct net_device *dev); 
   void (*ndo_change_rx_flags...