ENC28J60以太网之uIP协议

        广东省电子设计大赛准备的，智能家居网关，外围单片机通信数据需要使用TCP/IP通信，故采用ENC28J60模块。

       在嵌入式系统中，以太网控制器通常也是研究热点之一，MicroChip公司的ENC28J60在嵌入式系统中应用价值较高，该芯片集成了MAC控制器和PHY，使用SPI接口，适合在引脚资源比较紧张的嵌入式系统中加入以太网连接功能，本文主要介绍了MicroChip公司的ENC28J60控制器的初始化及其编程相关的注意和要点。

        uIP作为一种广泛使用的轻量级嵌入式TCP/IP协议栈，其UDP协议的实现还不够完善，目前最新的1.0版本中仅实现了UDP客户端，尚没有实现UDP服务端。为此，对其进行了以下三方面的改进：UDP服务端口的初始化；接收到UDP客户端数据包后的端口号判断及匹配；UDP服务端发送报文后目的端口的释放。

       硬件平台：STC12C60S2+ENC28J60

 

主函数main：在函数中，对于处理应用数据的用户，对 uIP 整个流程做一个了解即可，uIP 将处理后的结果全部
都回调到uip_appcall()函数统一处理， 所以重点需要完成的工作全部在uip_appcall()函数中

/*
 * Copyright (c) 2001-2003, Adam Dunkels.
 * 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 uIP TCP/IP stack.
 *
 * $Id: main.c,v 1.10.2.1 2003/10/04 22:54:17 adam Exp $
 *
 */
#include "uip.h" 
#include "uip_arp.h"
#include "httpd.h"
//#include "telnet.h"
#include "mcu_uart.h"
#include "enc28j60.h"
#include "tcp_server.h"

#define BUF ((struct uip_eth_hdr *)&uip_buf[0])

#ifndef NULL
#define NULL (void *)0
#endif /* NULL */

/*-----------------------------------------------------------------------------------*/
int
main(void)
{
	idata u8_t i, arptimer;
	idata u16_t j;
	init_uart();   //串口初始化
	printu("starting......\r\n");
	/* Initialize the device driver. */ 
	dev_init();	   //网卡初始化
	uip_arp_init();	//ARP初始化
	/* Initialize the uIP TCP/IP stack. */
	uip_init();	  //uIP协议初始化
	printu("uip\r\n");
	/* Initialize the HTTP server. */
//	httpd_init();
	tcp_server_init(); //用户自定义处，实现功能函数
	
	arptimer = 0;  //ARP缓存表更新定时器
	printu("ok\r\n");
  while(1) {
    /* Let the tapdev network device driver read an entire IP packet
       into the uip_buf. If it must wait for more than 0.5 seconds, it
       will return with the return value 0. If so, we know that it is
       time to call upon the uip_periodic(). Otherwise, the tapdev has
       received an IP packet that is to be processed by uIP. */
    uip_len = dev_poll();  //查询网卡是否有包收到
	for(j=0;j<500;j++);	   //延时，避免服务端应答过慢，造成不必要重发包
/*
	if(uip_len > 0)
	{
		printuf("--------------- uip_len = 0x%x", uip_len);
		printuf("%x ----------\r\n", uip_len);
		for(i=0;i<uip_len;i++)
		{
			printuf("%x ", uip_buf[i]);
			if((i+1)%16==0) printu("\r\n");			
		}
		printu("\r\n");			
	}
*/
    if(uip_len == 0) {
      for(i = 0; i < UIP_CONNS; i++) {	//协议栈解析，组包，状态监测等
	uip_periodic(i);
	/* If the above function invocation resulted in data that
	   should be sent out on the network, the global variable
	   uip_len is set to a value > 0. */
	if(uip_len > 0) {
	  uip_arp_out();			//有包需要发送
	  dev_send();
	}
      }

#if UIP_UDP
      for(i = 0; i < UIP_UDP_CONNS; i++) {
	uip_udp_periodic(i);
	/* If the above function invocation resulted in data that
	   should be sent out on the network, the global variable
	   uip_len is set to a value > 0. */
	if(uip_len > 0) {
	  uip_arp_out();
	  dev_send();
	}
      }
#endif /* UIP_UDP */
      
      /* Call the ARP timer function every 10 seconds. */
      if(++arptimer == 20) {	
	uip_arp_timer();	   //更新ARP缓存
	arptimer = 0;
      }
      
    } else {		//有包    处理IP包
      if(BUF->type == htons(UIP_ETHTYPE_IP)) {
	uip_arp_ipin();
	uip_input();
	/* If the above function invocation resulted in data that
	   should be sent out on the network, the global variable
	   uip_len is set to a value > 0. */
	if(uip_len > 0) {
	  uip_arp_out();
	  dev_send();
	}
      } else if(BUF->type == htons(UIP_ETHTYPE_ARP)) {		//处理ARP
	uip_arp_arpin();
	/* If the above function invocation resulted in data that
	   should be sent out on the network, the global variable
	   uip_len is set to a value > 0. */	
	if(uip_len > 0) {	
	  dev_send();
	}
      }
    }
    
  }
  return 0;
}
/*-----------------------------------------------------------------------------------*/
void
uip_log(char *m)
{
//  printf("uIP log message: %s\n", m);
}
/*-----------------------------------------------------------------------------------*/

在tcp_server_init(); //用户自定义处，实现功能函数中

#include "example0.h"
#include "example1.h"
#include "tcp_server.h"
//#include "httpd.h"
#include "uip.h"
#include "mcu_uart.h"


void tcp_server_init(void) 	//在应用程序函数中，依靠uIP事件检测函数来决定处理的方法，
							//另外可以通过判断当前连接的端口号来区分处理不同的连接。
{
	httpd_init();
	example0_init();   //用户自定义函数，实现某些功能的，主要监听端口
	example1_init();   //
}

void tcp_server_appcall(void) 
{
	switch(uip_conn->lport) 
	{
		case HTONS(80):
			httpd_appcall();break;
		case HTONS(8000):
			example0_app();break;
		case HTONS(8001):
			example1_app();break;
	}
}
				 

如example0_init中

void example0_init(void) 
{
	uip_listen(HTONS(8000));
}

 

究竟如何调用自己编写的函数呢？在uipopt.h中，可以修改IP地址，MAC，默认网关。实现的用户自定义的函数

 

#define UIP_PINGADDRCONF 0

#define UIP_IPADDR0     192 /**< The first octet of the IP address of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_IPADDR1     168 /**< The second octet of the IP address of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_IPADDR2     0   /**< The third octet of the IP address of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_IPADDR3     44  /**< The fourth octet of the IP address of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */

#define UIP_NETMASK0    255 /**< The first octet of the netmask of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_NETMASK1    255 /**< The second octet of the netmask of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_NETMASK2    255 /**< The third octet of the netmask of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_NETMASK3    0   /**< The fourth octet of the netmask of
			       this uIP node, if UIP_FIXEDADDR is
			       1. \hideinitializer */

#define UIP_DRIPADDR0   192 /**< The first octet of the IP address of
			       the default router, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_DRIPADDR1   168 /**< The second octet of the IP address of
			       the default router, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_DRIPADDR2   0   /**< The third octet of the IP address of
			       the default router, if UIP_FIXEDADDR is
			       1. \hideinitializer */
#define UIP_DRIPADDR3   1   /**< The fourth octet of the IP address of
			       the default router, if UIP_FIXEDADDR is
			       1. \hideinitializer */

/**
 * Specifies if the uIP ARP module should be compiled with a fixed
 * Ethernet MAC address or not.
 *
 * If this configuration option is 0, the macro uip_setethaddr() can
 * be used to specify the Ethernet address at run-time.
 *
 * \hideinitializer
 */
#define UIP_FIXEDETHADDR 1

#define UIP_ETHADDR0    0x12  /**< The first octet of the Ethernet
				 address if UIP_FIXEDETHADDR is
				 1. \hideinitializer */
#define UIP_ETHADDR1    0x34  /**< The second octet of the Ethernet
				 address if UIP_FIXEDETHADDR is
				 1. \hideinitializer */
#define UIP_ETHADDR2    0x56  /**< The third octet of the Ethernet
				 address if UIP_FIXEDETHADDR is
				 1. \hideinitializer */
#define UIP_ETHADDR3    0x78  /**< The fourth octet of the Ethernet
				 address if UIP_FIXEDETHADDR is
				 1. \hideinitializer */
#define UIP_ETHADDR4    0x90  /**< The fifth octet of the Ethernet
				 address if UIP_FIXEDETHADDR is
				 1. \hideinitializer */
#define UIP_ETHADDR5    0xAB  /**< The sixth octet of the Ethernet
				 address if UIP_FIXEDETHADDR is
				 1. \hideinitializer */

/*为了将用户的应用程序挂接到uIP中，必须将宏UIP_APPCALL()定义成实际的应用
  程序函数名，这样每当某个uIP事件发生时，内核就会调用该应用程序进行处理*/
#define UIP_APPCALL     tcp_server_appcall//httpd_appcall
/*

最后，如何进行测试呢：使用TCP/UDP 调试工具，上网下载的