stm32使用LWIP实现DHCP客户端

LWIP是一款开源的嵌入式网络协议栈,支持的功能很多,而且能在多任务环境下和单任务裸机环境下跑,今天说说他的移植过程,芯片为STM32,网卡为ENC28J60,无操作系统

首先下载LWIP的源代码,我下载的是1.4.1的源码,下载后解压,文件结构如图

将这四个目录中的文件全部拷贝到工程中,API是一些socket通讯的接口,需要在多任务的环境下实现,core里面存放的内核源码,我们主要使用IPV4,include目录下是需要包含的目录,lwip只要求我们包含include目录,里面的内层目录会自动找到,最后建立的工程目录如下

好了,此时源码已经做好,还有需要做的,在include目录下新建一个文件夹,必须叫arch,里面存放这几个文件,自己新建

文件的具体内容如下

cc.h

/*
 * 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 __CC_H__
#define __CC_H__

#include "cpu.h"

//编译器无关的数据类型定义
typedef unsigned   char    u8_t;
typedef signed     char    s8_t;
typedef unsigned   short   u16_t;
typedef signed     short   s16_t;
typedef unsigned   long    u32_t;
typedef signed     long    s32_t;
typedef u32_t mem_ptr_t;
typedef int sys_prot_t;

//lwip调试的时候数据类型定义
#define U16_F "hu"
#define S16_F "d"
#define X16_F "hx"
#define U32_F "u"
#define S32_F "d"
#define X32_F "x"
#define SZT_F "uz" 

//根据不同的编译器的符号定义
#if defined (__ICCARM__)

#define PACK_STRUCT_BEGIN
#define PACK_STRUCT_STRUCT
#define PACK_STRUCT_END
#define PACK_STRUCT_FIELD(x) x
#define PACK_STRUCT_USE_INCLUDES

#elif defined (__CC_ARM)

#define PACK_STRUCT_BEGIN __packed
#define PACK_STRUCT_STRUCT
#define PACK_STRUCT_END
#define PACK_STRUCT_FIELD(x) x

#elif defined (__GNUC__)

#define PACK_STRUCT_BEGIN
#define PACK_STRUCT_STRUCT __attribute__ ((__packed__))
#define PACK_STRUCT_END
#define PACK_STRUCT_FIELD(x) x

#elif defined (__TASKING__)

#define PACK_STRUCT_BEGIN
#define PACK_STRUCT_STRUCT
#define PACK_STRUCT_END
#define PACK_STRUCT_FIELD(x) x

#endif

#define LWIP_PLATFORM_ASSERT(x) //do { if(!(x)) while(1); } while(0)

#endif /* __CC_H__ */

cpu.h

/*
 * 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 __CPU_H__
#define __CPU_H__

//定义cpu的数据模式,大端小端
#define BYTE_ORDER LITTLE_ENDIAN

#endif /* __CPU_H__ */

perf.h

#ifndef __PERF_H__
#define __PERF_H__

//用于lwip内置的统计功能
//不使能定义为空就可以了
#define PERF_START    /* null definition */
#define PERF_STOP(x)  /* null definition */

#endif /* __PERF_H__ */

sys_arch.h

#ifndef __SYS_RTXC_H__
#define __SYS_RTXC_H__

void init_lwip_timer(void);  //初始化LWIP定时器

u8_t timer_expired(u32_t *last_time,u32_t tmr_interval);    //定时器超时判断

#endif /* __SYS_RTXC_H__ */

sya_arch.c--注意该文件要加入源文件列表中,这是c文件哦

#include "lwip/debug.h"
#include "lwip/def.h"
#include "lwip/sys.h"
#include "lwip/mem.h"
#include "timerx.h"

//初始化LWIP定时器
void init_lwip_timer(void)
{
     TIM6_Int_Init(,);//100Khz计数频率，计数到100为10ms
}

//为LWIP提供计时
extern u32_t lwip_timer;//lwip 计时器，每10ms增加1.

u32_t sys_now(void)
{
    return lwip_timer;
}

//定时器超时判断
//last_time:最近时间
//tmr_interval:定时器溢出周期
u8_t timer_expired(u32_t *last_time,u32_t tmr_interval)
{
    u32_t time;
    time = *last_time;
    if((lwip_timer-time)>=tmr_interval){
        *last_time = lwip_timer;
        return ;
    }
    return ;
}

可以看到我们定义了定时器,那么就要修改相关的定时器文件,文件如下

timerx.c

#include "timerx.h"

u32 lwip_timer=;//lwip 计时器，每10ms增加1.

//定时器6中断服务程序
void TIM6_IRQHandler(void)
{     

    if (TIM_GetITStatus(TIM6, TIM_IT_Update) != RESET) //检查指定的TIM中断发生与否:TIM 中断源
    {
        TIM_ClearITPendingBit(TIM6, TIM_IT_Update  );  //清除TIMx的中断待处理位:TIM 中断源
        lwip_timer++;//lwip计时器增加1
    }     

}

//基本定时器6中断初始化
//这里时钟选择为APB1的2倍，而APB1为36M
//arr：自动重装值。
//psc：时钟预分频数
//这里使用的是定时器3!
void TIM6_Int_Init(u16 arr,u16 psc)
{
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE); //时钟使能

    TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值     计数到5000为500ms
    TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值  10Khz的计数频率
    TIM_TimeBaseStructure.TIM_ClockDivision = ; //设置时钟分割:TDTS = Tck_tim
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式
    TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

    TIM_ITConfig( TIM6,TIM_IT_Update|TIM_IT_Trigger,ENABLE);//使能定时器6更新触发中断

    TIM_Cmd(TIM6, ENABLE);  //使能TIMx外设

      NVIC_InitStructure.NVIC_IRQChannel = TIM6_IRQn;  //TIM3中断
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ;  //先占优先级0级
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;  //从优先级3级
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
    NVIC_Init(&NVIC_InitStructure);  //根据NVIC_InitStruct中指定的参数初始化外设NVIC寄存器
}

timerx.h

#ifndef __TIMER_H_
#define __TIMER_H_

#include "sys.h"

void TIM6_Int_Init(u16 arr,u16 psc);

#endif

好了,这个时候移植就基本完成了,但是编译是过不了的,因为我们缺少一个配置文件.h,这个文件放哪都可以,只要工程包含这个文件的目录,另外,该文件名称不能改动

lwipopts.h

#ifndef __LWIPOPTS_H__
#define __LWIPOPTS_H__

//回环模式
//#define LWIP_HAVE_LOOPIF  1

/* Prevent having to link sys_arch.c (we don't test the API layers in unit tests) */
#define NO_SYS                          1    //是否使用操作系统
#define LWIP_NETCONN                    0
#define LWIP_SOCKET                     0

#define LWIP_DHCP                       1     //使能DHCP模块
#define MEM_ALIGNMENT                   4      //必须4字节对齐 曾出现在memset的时候hardfault
#define LWIP_DNS                        1

#define MEM_SIZE                        16000        //使用多大一块内存做lwip内存
#define TCP_SND_QUEUELEN                40            //tcp发送序列长度
#define MEMP_NUM_TCP_SEG                TCP_SND_QUEUELEN

#define TCP_MSS                     1460
#define TCP_WND                     (4 * TCP_MSS)
#define TCP_SND_BUF                 (8 * TCP_MSS)

#define ETHARP_SUPPORT_STATIC_ENTRIES   1

#endif /* __LWIPOPTS_H__ */

可以看到,我们没有使用操作系统并且使能了dhcp功能

这时候就可以编译通过了,但是还有一个必须做的工作,移植网卡的驱动到lwip中,

也就是netif文件夹中的ethernetif.c文件,该文件修改为如下内容

//网卡驱动层文件

#if 1 /* don't build, this is only a skeleton, see previous comment */

#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/pbuf.h"
#include <lwip/stats.h>
#include <lwip/snmp.h>
#include "netif/etharp.h"
#include "netif/ppp_oe.h"
#include "enc28j60.h"
#include "netif/ethernetif.h"
#include "string.h"
#include "delay.h"

/* Define those to better describe your network interface. */
#define IFNAME0 'e'
#define IFNAME1 'n'

//MAC地址
const u8 mymac[]={0x99,0x02,0x35,0x04,0x45,0x61};    //MAC地址
//定义发送接受缓冲区
u8 lwip_buf[*];

//返回网卡地址
struct ethernetif
{
  struct eth_addr *ethaddr;
  /* Add whatever per-interface state that is needed here. */
};

//网卡的初始化
static err_t low_level_init(struct netif *netif)
{
  //mac地址
  netif->hwaddr_len = ETHARP_HWADDR_LEN;
  /* set MAC hardware address */
  netif->hwaddr[] = mymac[];
  netif->hwaddr[] = mymac[];
  netif->hwaddr[] = mymac[];
  netif->hwaddr[] = mymac[];
  netif->hwaddr[] = mymac[];
  netif->hwaddr[] = mymac[];

  //最大传输单元
  netif->mtu = MAX_FRAMELEN;
  if(ENC28J60_Init((u8*)mymac))    //初始化ENC28J60
  {
    return ERR_IF;            //底层网络接口错误
  }
  //指示灯状态:0x476 is PHLCON LEDA(绿)=links status, LEDB(红)=receive/transmit
  //PHLCON：PHY 模块LED 控制寄存器
  ENC28J60_PHY_Write(PHLCON,0x0476);      

  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;

  return ERR_OK;
}

//从指定网卡输出一部分数据
static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
  struct pbuf *q;
  int send_len=;

#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);
    memcpy((u8_t*)&lwip_buf[send_len], (u8_t*)q->payload, q->len);
    send_len +=q->len;
  }
   // signal that packet should be sent();
  ENC28J60_Packet_Send(send_len,lwip_buf);

#if ETH_PAD_SIZE
  pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
#endif

  LINK_STATS_INC(link.xmit);

  return ERR_OK;
}

//从指定网卡读取一帧数据回来
static struct pbuf *low_level_input(struct netif *netif)
{
//  struct ethernetif *ethernetif = netif->state;
  struct pbuf *p, *q;
  u16_t len;
  int rev_len=;

  /* Obtain the size of the packet and put it into the "len"
     variable. */
  len = ENC28J60_Packet_Receive(MAX_FRAMELEN,lwip_buf);

#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);
        memcpy((u8_t*)q->payload, (u8_t*)&lwip_buf[rev_len],q->len);
        rev_len +=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;
}

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

 // ethernetif = netif->state;

  /* move received packet into a new pbuf */
  p = low_level_input(netif);
  /* no packet could be read, silently ignore this */
  if (p == NULL) return;
  /* points to packet payload, which starts with an Ethernet header */
  ethhdr = p->payload;

  switch (htons(ethhdr->type)) {
  /* IP or ARP packet? */
  case ETHTYPE_IP:
  case ETHTYPE_ARP:
#if PPPOE_SUPPORT
  /* PPPoE packet? */
  case ETHTYPE_PPPOEDISC:
  case ETHTYPE_PPPOE:
#endif /* PPPOE_SUPPORT */
    /* full packet send to tcpip_thread to process */
    if (netif->input(p, netif)!=ERR_OK)
     { LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
       pbuf_free(p);
       p = NULL;
     }
    break;

  default:
    pbuf_free(p);
    p = NULL;
    break;
  }
}

/**
 * Should be called at the beginning of the program to set up the
 * network interface. It calls the function low_level_init() to do the
 * actual setup of the hardware.
 *
 * This function should be passed as a parameter to netif_add().
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return ERR_OK if the loopif is initialized
 *         ERR_MEM if private data couldn't be allocated
 *         any other err_t on error
 */
err_t ethernetif_init(struct netif *netif)
{
  struct ethernetif *ethernetif;

  LWIP_ASSERT("netif != NULL", (netif != NULL));

  ethernetif = mem_malloc(sizeof(struct ethernetif));
  if (ethernetif == NULL) {
    LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_init: out of memory\n"));
    return ERR_MEM;
  }

#if LWIP_NETIF_HOSTNAME
  /* Initialize interface hostname */
  netif->hostname = "lwip";
#endif /* LWIP_NETIF_HOSTNAME */

  /*
   * Initialize the snmp variables and counters inside the struct netif.
   * The last argument should be replaced with your link speed, in units
   * of bits per second.
   */
  NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);

  netif->state = ethernetif;
  netif->name[] = IFNAME0;
  netif->name[] = IFNAME1;
  /* We directly use etharp_output() here to save a function call.
   * You can instead declare your own function an call etharp_output()
   * from it if you have to do some checks before sending (e.g. if link
   * is available...) */
  netif->output = etharp_output;
  netif->linkoutput = low_level_output;

  ethernetif->ethaddr = (struct eth_addr *)&(netif->hwaddr[]);

  /* initialize the hardware */
  return low_level_init(netif);

}

#endif 

主要是三个功能,网卡数据输入,网卡数据输入,网卡初始化,而且我们可以看到,lwip的配置是可以支持多个网卡滴

要是没有网卡驱动的可以看我之前的例程,里面有

这时候我们算是完整完成了lwip的移植,现在到了使用阶段了

这是我们的main函数

int main(void)
{
    NVIC_Group_Init();//系统默认中断分组
    Debug_Serial_Init();
    Delay_Init();
    Led_Init();
    Key_Exti_Init();
    LCD_Init();
    LCD_Clear(LCD_BLACK);

    ipaddr.addr = ;
    netmask.addr = ;
    gw.addr = ;
    init_lwip_timer();  //初始化LWIP定时器
    //初始化LWIP协议栈,执行检查用户所有可配置的值，初始化所有的模块
    lwip_init();

    //添加网络接口
    while((netif_add(&enc28j60_netif, &ipaddr, &netmask, &gw, NULL, &ethernetif_init, &ethernet_input)==NULL))
    {
        LCD_ShowString(,,,,(u8*)"ENC28J60 Init Failed             ",LCD_BLACK);
        Delay_Ms();
        LCD_ShowString(,,,,(u8*)"                                 ",LCD_BLACK);
        Delay_Ms();
    }
    LCD_ShowString(,,,,(u8*)"ENC28J60 Init OK                     ",LCD_BLACK);
    //注册默认的网络接口
    netif_set_default(&enc28j60_netif);
    //建立网络接口用于处理通信
    netif_set_up(&enc28j60_netif); 

    dhcp_start(&enc28j60_netif);             //为网卡创建一个新的DHCP客户端

    while()
    {
        LWIP_Polling();
        Led_Set(,);
        Delay_Ms();
        Led_Set(,);
        Delay_Ms();
    }
}

初始化定时器,初始化协议栈,添加网络接口(该函数同时完成网卡的初始化,mac地址在之前的文件中),注册网络接口,建立网络通讯接口,因为是dhcp,所以完全不用管网络的地址是多少,直接给0,后面他会自己获得到的

接下来启动dhcp服务,因为是裸机程序,没有多任务再跑,所以我们必须轮询系统事件并处理,也就是LWIP_Polling(),该函数如下

#define CLOCKTICKS_PER_MS 10    //定义时钟节拍

static ip_addr_t ipaddr, netmask, gw;     //定义IP地址
struct netif enc28j60_netif;              //定义网络接口
u32_t input_time;
u32_t last_arp_time;
u32_t last_tcp_time;
u32_t last_ipreass_time;

u32_t last_dhcp_fine_time;
u32_t last_dhcp_coarse_time;
u32 dhcp_ip=;

//LWIP查询
void LWIP_Polling(void)
{
    if(timer_expired(&input_time,)) //接收包，周期处理函数
    {
        ethernetif_input(&enc28j60_netif);
    }
    if(timer_expired(&last_tcp_time,TCP_TMR_INTERVAL/CLOCKTICKS_PER_MS))//TCP处理定时器处理函数
    {
        tcp_tmr();
    }
    if(timer_expired(&last_arp_time,ARP_TMR_INTERVAL/CLOCKTICKS_PER_MS))//ARP处理定时器
    {
        etharp_tmr();
    }
    if(timer_expired(&last_ipreass_time,IP_TMR_INTERVAL/CLOCKTICKS_PER_MS))//IP重新组装定时器
    {
        ip_reass_tmr();
    }
    if(timer_expired(&last_dhcp_fine_time,DHCP_FINE_TIMER_MSECS/CLOCKTICKS_PER_MS))//dhcp服务
    {
        dhcp_fine_tmr();
    }
    if(timer_expired(&last_dhcp_coarse_time,DHCP_COARSE_TIMER_MSECS/CLOCKTICKS_PER_MS))//dhcp服务
    {
        dhcp_coarse_tmr();
    }
}

在循环中处理好相应的事件,因为我们没建立tcp链接所以tcp其实可以不要,另外dhcp服务使用的是udp,端口使用的是udp的57,58

到这里编译连接,系统启动就能查看到路由器自动分配的IP了

具体工程在下面下载

http://download.csdn.net/detail/dengrengong/8548851