lwip---创建一个网络接口

struct netif {

   struct netif *next;   /** pointer to next in linked list */

 

  struct ip_addr ip_addr;
  struct ip_addr netmask;
  struct ip_addr gw;

 

   err_t (* input)(struct pbuf *p, struct netif *inp);

  err_t (* output)(struct netif *netif, struct pbuf *p,struct ip_addr *ipaddr);

    err_t (* linkoutput)(struct netif *netif, struct pbuf *p);

  void *state;

#if LWIP_DHCP
    struct dhcp *dhcp;
#endif

 
   unsigned char hwaddr_len;

   unsigned char hwaddr[NETIF_MAX_HWADDR_LEN];

    u16_t mtu;

  /** flags (see NETIF_FLAG_ above) */
  u8_t flags;

  /** link type */
  u8_t link_type;

  /** descriptive abbreviation */
  char name[2];

  /** number of this interface */
  u8_t num;
};