LwIP移植和使用

太过爱你忘了你带给我的痛 2021-12-05 02:57 367阅读 0赞

原文地址：[https://www.cnblogs.com/electron/p/3546508.html][https_www.cnblogs.com_electron_p_3546508.html]

LwIP移植和使用

本手册基于lwip-1.4.x编写，本人没有移植过1.4.0之前的版本，更早的版本或许有差别。如果看官发现问题欢迎联系<QQ: 937431539  email: [937431539@qq.com>][937431539_qq.com]

本文系个人原创，你可以转载，修改，重新发布，但请保留作者信息。

LwIP官网是：[http://savannah.nongnu.org/projects/lwip/][http_savannah.nongnu.org_projects_lwip]

你可以从这里获取源代码。当然也可以从Git获取源代码：

git clone git://git.savannah.nongnu.org/lwip.git

LwIP以BSD协议发布源代码，我们可以自由的使用，修改，发布或不发布源代码。

附件中有我移植的文件，可以用来参考。祝你移植顺利。

移植

1)新建几个头文件：

include/lwipopts.h         // lwip配置文件

include/arch/cc.h          // 平台相关。类型定义,大小端设置,内存对齐等

include/arch/perf.h        // 平台相关的性能测量实现(没用)

include/arch/sys\_arch.h    // RTOS抽象层。信号量，mbox等类型定义，函数声明

lwipopts.h                // lwip配置文件，详见附件

cc.h                      //类型定义,大小端设置,内存对齐等

![复制代码][copycode.gif]

#ifndef __CC_H__ 
    #define __CC_H__ 
    
    #include <stdint.h>
    
    /* Types based on stdint.h */
    typedef uint8_t            u8_t; 
    typedef int8_t             s8_t; 
    typedef uint16_t           u16_t; 
    typedef int16_t            s16_t; 
    typedef uint32_t           u32_t; 
    typedef int32_t            s32_t; 
    typedef uintptr_t          mem_ptr_t; 
     
    /* Define (sn)printf formatters for these lwIP types */
    #define U16_F "hu"
    #define S16_F "hd"
    #define X16_F "hx"
    #define U32_F "lu"
    #define S32_F "ld"
    #define X32_F "lx"
    #define SZT_F "uz"
     
    /* 选择小端模式 */
    #define BYTE_ORDER LITTLE_ENDIAN
     
    /* Use LWIP error codes */
    #define LWIP_PROVIDE_ERRNO
    
    /* 内存对齐 */
    #if defined(__arm__) && defined(__ARMCC_VERSION) 
    /* Keil uVision4 tools */
        #define PACK_STRUCT_BEGIN __packed
        #define PACK_STRUCT_STRUCT
        #define PACK_STRUCT_END
        #define PACK_STRUCT_FIELD(fld) fld
    #define ALIGNED(n)  __align(n)
    
    #endif

![复制代码][copycode.gif]

perf.h                     // 两个宏定义为空即可

![复制代码][copycode.gif]

#ifndef __PERF_H__
    #define __PERF_H__
    
    #define PERF_START    /* null definition */
    #define PERF_STOP(x)  /* null definition */
    
    #endif /* END __PERF_H__ */

![复制代码][copycode.gif]

sys\_arch.h

RTOS抽象层的类型定义，函数声明，详细内容见 doc/sys\_arch.h

2)建立RTOS抽象层文件：

port/sys\_arch.c            // RTOS抽象层实现

为了屏蔽不同RTOS在信号量，互斥锁，消息，任务创建等OS原语使用上的差别，lwip构造了一个RTOS的抽象层，规定了OS原语的数据类型名称和对应方法名称。我们要做的就是根据所用RTOS的api去实现这些原语。

比如移植lwip到raw-os上，信号量的移植：

类型定义，宏定义在sys\_arch.h中

![复制代码][copycode.gif]

struct _sys_sem 
    {
        RAW_SEMAPHORE *sem;
    };
    
    typedef struct _sys_sem sys_sem_t; // sys_sem_t是lwip的信号量类型名 
    #define SYS_SEM_NULL NULL 
    #define sys_sem_valid(sema) (((sema) != NULL) && ((sema)->sem != NULL)) 
    #define sys_sem_set_invalid(sema) ((sema)->sem = NULL) 
    err_t sys_sem_new(sys_sem_t *sem, u8_t count)
    { 
        RAW_SEMAPHORE *semaphore_ptr = 0;
        if (sem == NULL) 
        {
            RAW_ASSERT(0); 
        }
    
        semaphore_ptr = port_malloc(sizeof(RAW_SEMAPHORE));
        if(semaphore_ptr == 0)
        {
            RAW_ASSERT(0);
        }
    
        //这是raw-os的API 
        raw_semaphore_create(semaphore_ptr, (RAW_U8 *)"name_ptr", count);
        sem->sem = semaphore_ptr;
    
        return ERR_OK;
    } 
    
    void sys_sem_free(sys_sem_t *sem)
    {
        if((sem == NULL) || (sem->sem == NULL)) 
        {
            RAW_ASSERT(0);
        }
    
        raw_semaphore_delete(sem->sem); //这是raw-os的API 
    
        raw_memset(sem->sem, sizeof(RAW_SEMAPHORE), 0); 
        port_free(sem->sem);
        sem->sem = NULL;
    }

![复制代码][copycode.gif]

还有几个函数就不一一列举了，如有疑问看doc/sys\_arch.txt

3)修改网卡框架文件：

netif/ethernetif.c

该文件是作者提供的网卡驱动和lwip的接口框架。

该文件中要改动的函数只有3个:

static void   low\_level\_init(struct netif \*netif);

static err\_t  low\_level\_output(struct netif \*netif, struct pbuf \*p);

static struct pbuf \*low\_level\_input(struct netif \*netif);

![复制代码][copycode.gif]

/* 你可以给网卡起个名字 */
    /* Define those to better describe your network interface. */
    #define IFNAME0 'e'
    #define IFNAME1 '0'
    
    /**
     * Helper struct to hold private data used to operate your ethernet
     * interface.
     * Keeping the ethernet address of the MAC in this struct is not
     * necessary as it is already kept in the struct netif.
     * But this is only an example, anyway...
     */
    struct ethernetif 
    {
        struct eth_addr *ethaddr;
        // Add whatever per-interface state that is needed here.
        // 在这里添加网卡的私有数据，比如和网卡相关的信号量，互斥锁，
        // 网卡状态等等，这不是必须的
    };

![复制代码][copycode.gif]

3个网卡相关的函数只要改动红色部分，需根据具体的网卡驱动函数改动

![复制代码][copycode.gif]

static void low_level_init(struct netif *netif)
    {
        struct ethernetif *ethernetif = netif->state;
    
        /* set MAC hardware address length */
        netif->hwaddr_len = ETHARP_HWADDR_LEN;
    
        /* 设置MAC地址, 必须与网卡初始化的地址相同 */
        netif->hwaddr[0] = ;
        netif->hwaddr[1] = ;
        netif->hwaddr[2] = ;
        netif->hwaddr[3] = ;
        netif->hwaddr[4] = ;
        netif->hwaddr[5] = ;
    
        /* maximum transfer unit */
        netif->mtu = 1500;
    
        /* device capabilities */
        /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
        netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;
    
        /* 在这里添加其他初始化代码(如真正的网卡初始化, phy初始化等) */ 
    }
    
     
    
    static err_t low_level_output(struct netif *netif, struct pbuf *p)
    {
        struct ethernetif *ethernetif = netif->state;
        struct pbuf *q;
     
        initiate transfer();
    
    #if ETH_PAD_SIZE
        pbuf_header(p, -ETH_PAD_SIZE);   /* drop the padding word */
    #endif
     
        for(q = p; q != NULL; q = q->next){
            /* Send the data from the pbuf to the interface, one pbuf at a
                time. The size of the data in each pbuf is kept in the ->len
                variable. */
            send data from(q->payload, q->len);
        }
    
        signal that packet should be sent();
    
    #if ETH_PAD_SIZE
        pbuf_header(p, ETH_PAD_SIZE);   /* reclaim the padding word */
    #endif
    
        LINK_STATS_INC(link.xmit);
     
        return ERR_OK;
    }
    
    static struct pbuf * low_level_input(struct netif *netif)
    {
        struct ethernetif *ethernetif = netif->state;
        struct pbuf *p, *q;
        u16_t len;
    
        /* Obtain the size of the packet and put it into the "len" variable. */
        len = ;  // 获取将要接收的数据长度
    
    #if ETH_PAD_SIZE
        len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
    #endif
    
        /* We allocate a pbuf chain of pbufs from the pool. */
        p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
    
        if (p != NULL){ 
    #if ETH_PAD_SIZE
            pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
    #endif
    
            /* We iterate over the pbuf chain until we have read the entire
             * packet into the pbuf. */
            for(q = p; q != NULL; q = q->next) {
                /* Read enough bytes to fill this pbuf in the chain. The
                 * available data in the pbuf is given by the q->len
                 * variable.
                 * This does not necessarily have to be a memcpy, you can also 
                 * preallocate pbufs for a DMA-enabled MAC and after receiving truncate 
                 * it to the actually received size. In this case, ensure the tot_len 
                 * member of the pbuf is the sum of the chained pbuf len members.
                 */
                read data into(q->payload, q->len);
            }
    
            acknowledge that packet has been read();
    
    #if ETH_PAD_SIZE
            pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
    #endif
    
            LINK_STATS_INC(link.recv); 
        } 
        else 
        {
            drop packet();
            LINK_STATS_INC(link.memerr);
            LINK_STATS_INC(link.drop);
        }
    
        return p;  
    }

![复制代码][copycode.gif]

LwIP的使用

LwIP的初始化：

LwIP的初始化必须在RTOS启动之后才可以进行, 因为它的初始化代码使用了一些OS提供的功能！！！

初始化代码示例：

![复制代码][copycode.gif]

extern err_t ethernetif_init(struct netif *netif);
    struct netif lpc1788_netif;
    ip_addr_t e0ip, e0mask, e0gw;
    
    /* tcpip_init使用的回调函数，用于判断tcpip_init初始化完成 */
    static void tcpip_init_done(void *pdat)
    {
        *(int *)pdat = 0;
    }
    
    void  ethernetif_input(struct netif *netif);
    // 一直调用ethernetif_input函数，从网卡读取数据
    static void lwip_read_task(void *netif)
    {
        while(1)
        {
            ethernetif_input(netif);
        }
    }
     
    void init_lwip()
    {
        struct netif *pnetif = NULL;
        int flag = 1;
    
        tcpip_init(tcpip_init_done, &flag);  // lwip协议栈的初始化
        while(flag);
    
        IP4_ADDR(&e0ip, 192,168,6,188);      // 设置网卡ip
        IP4_ADDR(&e0mask, 255,255,255,0);    // 设置子网掩码
        IP4_ADDR(&e0gw, 192,168,6,1);        // 设置网关
    
        //给lwip添加网卡
        pnetif = netif_add(&lpc1788_netif, &e0ip, &e0mask, &e0gw,
                           NULL, ethernetif_init, tcpip_input);
        netif_set_default(pnetif);     // 设置该网卡为默认网卡
        netif_set_up(&lpc1788_netif);  // 启动网卡，可以唤醒DHCP等服务
    
        // 创建一个任务。这个任务负责不停的调用ethernetif_input函数从网卡读取数据
        raw_task_create(&lwip_read_obj, (RAW_U8  *)"lwip_read", &lpc1788_netif,
                        CONFIG_RAW_PRIO_MAX - 25, 0,  lwip_read_stk, 
                        LWIP_READ_STK_SIZE ,  lwip_read_task, 1);  
    }

![复制代码][copycode.gif]

**附件:**

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分类: [单片机][Link 1],[网络][Link 2]

标签: [lwip][], [移植][Link 3]

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posted @ 2014-02-12 20:12 [electron][] 阅读(9810) 评论(4) [编辑][Link 6] [收藏][Link 7]

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[\#1楼][1] 2014-02-13 10:10 [cronus象牙塔][cronus] [ ][Link 8]

请问你是在什么平台上移植的，加操作系统了吗？

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[\#2楼][2]\[楼主\] 2014-02-13 10:11 [electron][] [ ][Link 9]

[@][1] cronus象牙塔  
在raw-os上移植的，整个系统跑在lpc1788, lpc4337上

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[\#3楼][3] 2014-02-13 10:15 [cronus象牙塔][cronus] [ ][Link 8]

移植操作系统后， low\_level\_input(struct netif \*netif)函数里加信号量了吗？就这个为什么在这里加信号量，请指教！

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[\#4楼][4]\[楼主\] 2014-02-13 10:20 [electron][] [ ][Link 9]

[@][3] cronus象牙塔  
加了。在low\_level\_input函数里会调用真正从网卡读取数据的函数，假定是eth\_read。在eth\_read中加了信号量的P操作，尝试获取信号量。然后再网卡中断中会有信号量的V操作，发送一个信号量。我在移植中就使用了计数信号量。这样做的目的是为了实现异步运行。

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