【原创】LWIP-1.2.0+RTL8019+uC/OS-II--代码篇2

本文详细解析了LWIP中的ethernetif.c文件，介绍了其核心函数ethernetif_input的功能实现过程，包括如何接收、处理以太网数据包，并根据不同类型的数据包进行相应的操作。

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在LWIP中需要添加的驱动的位置：ethernetif.c文件

void ethernetif_input(struct netif *netif)
{
struct ethernetif *ethernetif;
struct eth_hdr *ethhdr;
struct pbuf *p;

while(1)
{
   ethernetif = netif->state;
   do{
   p = low_level_input(netif);
   if (p == NULL)
     OSTimeDlyHMSM(0,0,0,100);
   }while(p == NULL);

#if LINK_STATS
lwip_stats.link.recv++;
#endif

   ethhdr = p->payload;

   switch (htons(ethhdr->type)) {

   case ETHTYPE_IP:
#if 1
     etharp_ip_input(netif, p); //更新ARP表
#endif
   //跳过以太网头部字段
     pbuf_header(p, -sizeof(struct eth_hdr));
     //传递到网络层
     netif->input(p, netif);
     break;

     case ETHTYPE_ARP:
       //将netif传递到ARP模块
       p = etharp_arp_input(netif, ethernetif->ethaddr, p);
       if(p != NULL) {
         low_level_output(netif, p);
        pbuf_free(p);
       p = NULL;
      }
       break;
     default:
       pbuf_free(p);
      p = NULL;
       break;
   }
}
}

static struct pbuf * low_level_input(struct netif *netif)
{
struct ethernetif *ethernetif;
struct pbuf *p = NULL, *q;
u16_t len;

int flag;

unsigned int i;
unsigned char buffer[4096];
unsigned char *des;
unsigned char *data;

data = buffer;

ethernetif = netif->state;

flag = board_eth_rcv(data,&len);

#if 0
if(flag == 1) {
  des = data;
  LWIP_DEBUGF(RTL8019_DEBUG, ("\r\n"));
  for(i=0; i<len; i++) {
   LWIP_DEBUGF(RTL8019_DEBUG, ("0x%02X ",*des++));
  }
  LWIP_DEBUGF(RTL8019_DEBUG, ("\r\n"));
  LWIP_DEBUGF(RTL8019_DEBUG, ("\r\n"));
  LWIP_DEBUGF(RTL8019_DEBUG, ("the receive data length is %d\r\n",len));
  LWIP_DEBUGF(RTL8019_DEBUG, ("\r\n"));

}
#endif

if(flag == 1) {
  #if ETH_PAD_SIZE
   len += ETH_PAD_SIZE;
  #endif

   //p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
   //Modify by Small.Box at 06.10.16
   if(p == NULL) {
     p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
   }

   if (p != NULL) {

   #if ETH_PAD_SIZE
       pbuf_header(p, -ETH_PAD_SIZE);
   #endif

      for(q = p; q != NULL; q = q->next) {
    memcpy(q->payload,(unsigned char *)data, q->len);
        data += q->len;
      }

   #if ETH_PAD_SIZE
       pbuf_header(p, ETH_PAD_SIZE);
   #endif

   #if LINK_STATS
       lwip_stats.link.recv++;
   #endif
   } else {
   #if LINK_STATS
       lwip_stats.link.memerr++;
       lwip_stats.link.drop++;
   #endif
   }
}

return p;
}

static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
struct ethernetif *ethernetif;
struct pbuf *q;

ethernetif= netif->state;

#if ETH_PAD_SIZE
pbuf_header(p, -ETH_PAD_SIZE);
#endif

for(q = p; q != NULL; q = q->next) {
board_eth_send(q->payload,q->len);
}

#if ETH_PAD_SIZE
pbuf_header(p, ETH_PAD_SIZE);
#endif

#if LINK_STATS
lwip_stats.link.xmit++;
#endif /* LINK_STATS */

return ERR_OK;
}