LwIP移植和使用
本手冊基於lwip-1.4.x編寫，本人沒有移植過1.4.0之前的版本，更早的版本或許有差別。如果看官發現問題歡迎聯系<QQ: 937431539 email: 937431539@qq.com>
本文系個人原創，你可以轉載，修改，重新發布，但請保留作者信息。
LwIP官網是：http://savannah.nongnu.org/projects/lwip/
你可以從這里獲取源代碼。當然也可以從Git獲取源代碼：
git clone git://git.savannah.nongnu.org/lwip.git
LwIP以BSD協議發布源代碼，我們可以自由的使用，修改，發布或不發布源代碼。
附件中有我移植的文件，可以用來參考。祝你移植順利。
移植
1)新建幾個頭文件：
include/lwipopts.h // lwip配置文件
include/arch/cc.h // 平台相關。類型定義,大小端設置,內存對齊等
include/arch/perf.h // 平台相關的性能測量實現(沒用)
include/arch/sys_arch.h // RTOS抽象層。信號量，mbox等類型定義，函數聲明
lwipopts.h // lwip配置文件，詳見附件
cc.h //類型定義,大小端設置,內存對齊等
#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" /* 選擇小端模式 */ #define BYTE_ORDER LITTLE_ENDIAN /* Use LWIP error codes */ #define LWIP_PROVIDE_ERRNO /* 內存對齊 */ #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
perf.h // 兩個宏定義為空即可
#ifndef __PERF_H__ #define __PERF_H__ #define PERF_START /* null definition */ #define PERF_STOP(x) /* null definition */ #endif /* END __PERF_H__ */
sys_arch.h
RTOS抽象層的類型定義，函數聲明，詳細內容見 doc/sys_arch.h
2)建立RTOS抽象層文件：
port/sys_arch.c // RTOS抽象層實現
為了屏蔽不同RTOS在信號量，互斥鎖，消息，任務創建等OS原語使用上的差別，lwip構造了一個RTOS的抽象層，規定了OS原語的數據類型名稱和對應方法名稱。我們要做的就是根據所用RTOS的api去實現這些原語。
比如移植lwip到raw-os上，信號量的移植：
類型定義，宏定義在sys_arch.h中
struct _sys_sem { RAW_SEMAPHORE *sem; }; typedef struct _sys_sem sys_sem_t; // sys_sem_t是lwip的信號量類型名 #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); } //這是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); //這是raw-os的API raw_memset(sem->sem, sizeof(RAW_SEMAPHORE), 0); port_free(sem->sem); sem->sem = NULL; }
還有幾個函數就不一一列舉了，如有疑問看doc/sys_arch.txt
3)修改網卡框架文件：
netif/ethernetif.c
該文件是作者提供的網卡驅動和lwip的接口框架。
該文件中要改動的函數只有3個:
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);
/* 你可以給網卡起個名字 */ /* 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. // 在這里添加網卡的私有數據，比如和網卡相關的信號量，互斥鎖， // 網卡狀態等等，這不是必須的 };
3個網卡相關的函數只要改動紅色部分，需根據具體的網卡驅動函數改動
static void low_level_init(struct netif *netif) { struct ethernetif *ethernetif = netif->state; /* set MAC hardware address length */ netif->hwaddr_len = ETHARP_HWADDR_LEN; /* 設置MAC地址, 必須與網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; /* 在這里添加其他初始化代碼(如真正的網卡初始化, 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 = ; // 獲取將要接收的數據長度 #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; }
LwIP的使用
LwIP的初始化：
LwIP的初始化必須在RTOS啟動之后才可以進行, 因為它的初始化代碼使用了一些OS提供的功能！！！
初始化代碼示例：
extern err_t ethernetif_init(struct netif *netif); struct netif lpc1788_netif; ip_addr_t e0ip, e0mask, e0gw; /* tcpip_init使用的回調函數，用於判斷tcpip_init初始化完成 */ static void tcpip_init_done(void *pdat) { *(int *)pdat = 0; } void ethernetif_input(struct netif *netif); // 一直調用ethernetif_input函數，從網卡讀取數據 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協議棧的初始化 while(flag); IP4_ADDR(&e0ip, 192,168,6,188); // 設置網卡ip IP4_ADDR(&e0mask, 255,255,255,0); // 設置子網掩碼 IP4_ADDR(&e0gw, 192,168,6,1); // 設置網關 //給lwip添加網卡 pnetif = netif_add(&lpc1788_netif, &e0ip, &e0mask, &e0gw, NULL, ethernetif_init, tcpip_input); netif_set_default(pnetif); // 設置該網卡為默認網卡 netif_set_up(&lpc1788_netif); // 啟動網卡，可以喚醒DHCP等服務 // 創建一個任務。這個任務負責不停的調用ethernetif_input函數從網卡讀取數據 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); }
附件: