/* * Copyright (c) 2001-2003 Swedish Institute of Computer Science. * All rights reserved.  *  * Redistribution and use in source and binary forms, with or without modification,  * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, *    this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, *    this list of conditions and the following disclaimer in the documentation *    and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products *    derived from this software without specific prior written permission.  * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY  * OF SUCH DAMAGE. * * This file is part of the lwIP TCP/IP stack. *  * Author: Adam Dunkels <adam@sics.se> * */#ifndef __LWIP_NETIF_H__#define __LWIP_NETIF_H__#include "lwip/opt.h"#include "lwip/err.h"#include "lwip/ip_addr.h"#include "lwip/inet.h"#include "lwip/pbuf.h"#if LWIP_DHCP#include "dhcp.h"#endif/** must be the maximum of all used hardware address lengths    across all types of interfaces in use */#define NETIF_MAX_HWADDR_LEN 3U  //modify by zhigang/** TODO: define the use (where, when, whom) of netif flags *//** whether the network interface is 'up'. this is * a software flag used to control whether this network * interface is enabled and processes traffic */#define NETIF_FLAG_UP 0x1U/** if set, the netif has broadcast capability */#define NETIF_FLAG_BROADCAST 0x2U/** if set, the netif is one end of a point-to-point connection */#define NETIF_FLAG_POINTTOPOINT 0x4U/** if set, the interface is configured using DHCP */#define NETIF_FLAG_DHCP 0x08U/** if set, the interface has an active link *  (set by the interface) */#define NETIF_FLAG_LINK_UP 0x10U/** generic data structure used for all lwIP network interfaces */struct netif {  /** pointer to next in linked list */  struct netif *next;  /** The following fields should be filled in by the      initialization function for the device driver. */    /** IP address configuration in network byte order */  struct ip_addr ip_addr;  struct ip_addr netmask;  struct ip_addr gw;  /** This function is called by the network device driver      to pass a packet up the TCP/IP stack. */  err_t (* input)(struct pbuf *p, struct netif *inp);  /** This function is called by the IP module when it wants      to send a packet on the interface. This function typically      first resolves the hardware address, then sends the packet. */  err_t (* output)(struct netif *netif, struct pbuf *p,		   struct ip_addr *ipaddr);  /** This function is called by the ARP module when it wants      to send a packet on the interface. This function outputs      the pbuf as-is on the link medium. */  err_t (* linkoutput)(struct netif *netif, struct pbuf *p);  /** This field can be set by the device driver and could point      to state information for the device. */  void *state;#if LWIP_DHCP  /** the DHCP client state information for this netif */  struct dhcp *dhcp;#endif  /** number of bytes used in hwaddr */  unsigned char hwaddr_len;  /** link level hardware address of this interface */  unsigned char hwaddr[NETIF_MAX_HWADDR_LEN];  /** maximum transfer unit (in bytes) */  u16_t mtu;  /** descriptive abbreviation */  char name[2];  /** number of this interface */  u8_t num;  /** NETIF_FLAG_* */  u8_t flags;};/** The list of network interfaces. */extern struct netif *netif_list;/** The default network interface. */extern struct netif *netif_default;/* netif_init() must be called first. */void netif_init(void);struct netif *netif_add(struct ip_addr *ipaddr, struct ip_addr *netmask,			struct ip_addr *gw,			void *state,			err_t (* init)(struct netif *netif),			err_t (* input)(struct pbuf *p, struct netif *netif));voidnetif_set_addr(struct netif *netif,struct ip_addr *ipaddr, struct ip_addr *netmask,	  struct ip_addr *gw);void netif_remove(struct netif * netif);/* Returns a network interface given its name. The name is of the form   "et0", where the first two letters are the "name" field in the   netif structure, and the digit is in the num field in the same   structure. */struct netif *netif_find(char *name);void netif_set_default(struct netif *netif);void netif_set_ipaddr(struct netif *netif, struct ip_addr *ipaddr);void netif_set_netmask(struct netif *netif, struct ip_addr *netmast);void netif_set_gw(struct netif *netif, struct ip_addr *gw);#endif /* __LWIP_NETIF_H__ */