LWIP结构

协议栈文件Lwip.c封装接口： void Init_lwIP(void) {

struct ip_addr ip, mask, gw; static struct netif netif;

sys_sem_t sem;

/*****TCP/IP 初始化******/ sem = sys_sem_new(0);

uint8_t macaddress[6]={0,0,0,0,0,1}; //根据实际MAC地址赋值

tcpip_init(TcpipInitDone, &sem); sys_sem_wait(sem); sys_sem_free(sem);

#if LWIP_DHCP ipaddr.addr = 0; netmask.addr = 0; gw.addr = 0; #else

IP4_ADDR(&ipaddr, 10, 21, 11, 245); IP4_ADDR(&netmask, 255, 255, 255, 0); IP4_ADDR(&gw, 10, 21, 11, 254); #endif

Set_MAC_Address(macaddress);

netif_add(&netif, &ipaddr, &netmask, &gw, NULL, ðernetif_init, &tcpip_input); netif_set_default(&netif);

#if LWIP_DHCP dhcp_start(&netif); #endif

netif_set_up(&netif); }

/*****等待Tcpip初始化完成*******/ static void TcpipInitDone(void *arg) {

sys_sem_t *sem; sem = arg;

sys_sem_signal(*sem); }

网络接口文件Ethernetif.c封装接口：

全局变量： uint8_t MACaddr[6];

/*******设置MAC地址，赋值全局变量**********/ void Set_MAC_Address(uint8_t* macadd) { }

/**********初始化网络底层接口*************/ err_t ethernetif_init(struct netif *netif) {

1、 设置网卡相关属性（填充结构体ethernetif）；

2、 注册链路层发送函数low_level_output（给出框架，结合MAC芯片实际情况编写）； 3、 ethernetif->ethaddr 指针指向 netif 中保存的网卡 MAC 地址； 4、 网卡初始化low_level_init（）； }

注释：该接口无需用户改动。

/*****该函数是实际传输数据包，数据包包含pbuf –>payload，pbuf可能是个链表******/ static err_t low_level_output(struct netif *netif, struct pbuf *p) {

struct pbuf *q; int frameLen = 0; u8 *buffer = NULL;

/******声明一个状态保护变量******/ SYS_ARCH_DECL_PROTECT(sr);

/*********Interrupts are disabled through this whole thing to support multi-threading transmit calls. Also this function might be called from an ISR.********/ SYS_ARCH_PROTECT(sr);

buffer = (u8 *)ETH_GetCurrentTxBuffer(); for(q = p; q != NULL; q = q->next) {

memcpy((u8_t*)&buffer[l], q->payload, q->len); /****MAC芯片****/

ETH_MACAddressConfig(ETH_MAC_Address0, macadd); MACaddr[0] = macadd[0]; ……………………………. MACaddr[5] = macadd[5];

}

l = l + q->len;

ETH_TxPkt_ChainMode(l);

/****退出保护模式***/

SYS_ARCH_UNPROTECT(sr);

return ERR_OK; }

/*******返回缓冲区地址*******/ u32 ETH_GetCurrentTxBuffer(void);

/*******从应用程序的缓冲区，发送一个数据包*****/ ETH_TxPkt_ChainMode(l);

/***********/

static void low_level_init(struct netif *netif) {

SYS_ARCH_DECL_PROTECT(sr);

1、 设置MAC、最大传输单元（1500bytes）；

2、 设备功能（NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP）； SYS_ARCH_PROTECT(sr);

ETH_MACInit(); }

/*******初始化MAC*******/ void ETH_MACInit(void); /**

* This function should be called when a packet is ready to be read from the interface. It uses the function low_level_input() that should handle the actual reception of bytes from the network interface. Then the type of the received packet is determined and the appropriate input function is called. *

* @param netif the lwip network interface structure for this ethernetif */

err_t ethernetif_input(struct netif *netif) {

/* Enable MAC and DMA transmission and reception */ ETH_Start();

SYS_ARCH_UNPROTECT(sr);

SYS_ARCH_DECL_PROTECT(sr); SYS_ARCH_PROTECT(sr);

SYS_ARCH_PROTECT(sr);

/* move received packet into a new pbuf */ p = low_level_input(netif); SYS_ARCH_UNPROTECT(sr);

/* no packet could be read, silently ignore this */ if (p == NULL) return ERR_MEM;

err = netif->input(p, netif); // 将pbuf传递给上层协议栈 if (err != ERR_OK) {

LWIP_DEBUGF(NETIF_DEBUG, (\pbuf_free(p); p = NULL;

} /**

}

return err;

* Should allocate a pbuf and transfer the bytes of the incoming packet from the interface into the pbuf. *

* @param netif the lwip network interface structure for this ethernetif * @return a pbuf filled with the received packet (including MAC header) * NULL on memory error */

static struct pbuf * low_level_input(struct netif *netif) {

FrameTypeDef frame;

struct pbuf *p,*q; int l=0; u8 *buffer;

frame = ETH_RxPkt_ChainMode(); len=frame.length;

buffer = (u8 *)frame.buffer;

/* We allocate a pbuf chain of pbufs from the pool. */ p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL); if(p!=NULL) {

for(q=p;q!=NULL;q=q->next) {