4.物联网LWIP之C/S编程，stm32作为服务器，stm32作为客户端，代码的优化

LWIP配置

服务器端实现

客户端实现

错误分析

一。LWIP配置（FREERTOS配置，ETH配置，LWIP配置）

1.FREERTOS配置

 为什么要修改定时源为Tim1？不用systick？

原因：HAL库与FREERTOS都需要使用systick，两者冲突，所以修改时钟源，让FREERTOS使用Tim1。

 2.ETH配置

 3.LWIP配置

不使用DHCP

 4.步骤：
（1）freertos.c中会自己出现一个Lwip初始化

运行后结果：命令行中输入ping 192.168.1.10有回复

 二。服务器端

实验一：《stm32作为服务器端，COMMBOX串口作为客户端》

1.功能分析

小写转大写

 2.步骤：

（1）建立socket_tcp_server.h

#ifndef SOCKET_TCP_SERVER_H
#define SOCKET_TCP_SERVER_H#define SERVER_IP				"192.168.1.11"
#define SERVER_PORT			6666
#define BUFF_SIZE				1024void vTcpServerTask(void);#endif

 （2）建立socket_tcp_server.c，并添加到文件中

#include "socket_tcp_server.h"
#include "lwip/sockets.h"
#include "ctype.h"char ReadBuff[BUFF_SIZE];/*** @brief  TCP 服务器任务* @param  None* @retval None*/
void vTcpServerTask(void){int 	 sfd, cfd, n, i;struct sockaddr_in server_addr, client_addr;socklen_t	client_addr_len;//创建socketsfd = socket(AF_INET, SOCK_STREAM, 0);server_addr.sin_family 			= AF_INET;server_addr.sin_port   			= htons(SERVER_PORT);server_addr.sin_addr.s_addr = htonl(INADDR_ANY);//绑定socketbind(sfd, (struct sockaddr *)&server_addr, sizeof(server_addr));//监听socketlisten(sfd, 5);//等待客户端连接client_addr_len = sizeof(client_addr);cfd = accept(sfd, (struct sockaddr *)&client_addr, &client_addr_len);printf("client is connect cfd = %d\r\n",cfd);while(1){//等待客户端发送数据n = read(cfd, ReadBuff, BUFF_SIZE);//进行大小写转换for(i = 0; i < n; i++){ReadBuff[i] = toupper(ReadBuff[i]);		}//写回客户端write(cfd, ReadBuff, n);}
}

（3）freertos.c中网络任务中，添加服务器运行函数。

 不要忘记添加头文件

	vTcpServerTask();	

3.现象演示

（1）使用COMMBOX串口调试工程，添加socket网络客户端 ，目标ip为stm32的ip.端口在.h中

（2）stm32客户端发送的字母变大写

 三。客户端创建

实验二：《stm32作为客户端，COMMBOX串口作为服务器端》

1.创建socket_tcp_client.c与socket_tcp_client.h

（1）socket_tcp_client.c

#include "socket_tcp_server.h"
#include "socket_tcp_client.h"
#include "lwip/sockets.h"
#include "ctype.h"static char ReadBuff[BUFF_SIZE];void vTcpClientTask(void)
{int 	 cfd, n, i;struct sockaddr_in server_addr;//创建socketcfd = socket(AF_INET, SOCK_STREAM, 0);server_addr.sin_family 			= AF_INET;server_addr.sin_port   			= htons(SERVER_PORT);server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);//连接到服务器connect(cfd, (struct sockaddr*)&server_addr, sizeof(server_addr));printf("server is connect ok\r\n");while(1){//等待服务器发送数据n = read(cfd, ReadBuff, BUFF_SIZE);//进行大小写转换for(i = 0; i < n; i++){ReadBuff[i] = toupper(ReadBuff[i]);		}//写回服务器write(cfd, ReadBuff, n);}
}

（2）socket_tcp_client.h

#ifndef _SOCKET_TCP_CLIENT_H
#define _SOCKET_TCP_CLIENT_Hvoid vTcpClientTask(void);#endif

可能遇到的问题：

        由于打开了防火墙，所以无法连接

 

 补充：上述代码的问题

        1.代码封装性不好

        2.代码对边界错误提示太少

四。代码的优化

1.函数在封装，文件为socket_warp.c与socket_warp.h

（1）socket_warp.h

#ifndef _SOCKET_WRAP_H
#define _SOCKET_WRAP_H#include "lwip/sockets.h"int Socket(int domain, int type, int protocol);int Bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);int Listen(int sockfd, int backlog);int Accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
int Connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);int Write(int fd,const void *buf,size_t nbytes);
int Read(int fd,void *buf,size_t nbyte);int Sendto(int sockfd, const void *msg, int len, unsigned int flags, const struct sockaddr *to, int tolen);
int Recvfrom(int sockfd, void *buf, int len, unsigned int flags, struct sockaddr *from, socklen_t *fromlen);#endif

(2)socket_warp.c

#include "socket_wrap.h"
#include "FreeRTOS.h"
#include "task.h"int Socket(int domain, int type, int protocol){int fd;fd=socket(domain,type,protocol);if(fd<0){printf("create socket error\n");//没有创建完成，那么这个任务也没有必要运行，直接切换上下文//返回一个小于零的数vTaskDelete(NULL);}return fd;
}int Bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen){int ret;ret=bind(sockfd,addr,addrlen);if(ret < 0){printf("bind socket error\r\n");//当调用删除任务，就会切换上下文，CPU执行其他任务vTaskDelete(NULL);		}return ret;
}int Listen(int sockfd, int backlog){int ret;ret=listen(sockfd,backlog);if(ret<0){printf("listen socket error\n");vTaskDelete(NULL);}return ret;
}int Accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen){int fd;
again:	fd=accept(sockfd,addr,addrlen);if(fd<0){printf("accept socket error\n");goto again;}return fd;
}
int Connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen){int ret;ret=connect(sockfd,addr,addrlen);if(ret<0){printf("connect socket error\n");//先关闭当前的socket，其实内部是删除这个socket的内存块，不删除会导致下次无法生成close(sockfd);}return ret;
}int Write(int fd,const void *buf,size_t nbytes){int ret;ret=write(fd,buf,nbytes);//没有书写完成就关闭socketif(ret<0){printf("write socket error\n");close(fd);}return ret;
}
int Read(int fd,void *buf,size_t nbyte){int ret;ret=read(fd,buf,nbyte);if(ret==0){printf("read socket is close\n");close(fd);}else if(ret<0){printf("read socket error\n");close(fd);}
}int Sendto(int sockfd, const void *msg, int len, unsigned int flags, const struct sockaddr *to, int tolen){int ret;
again:	ret=sendto(sockfd,msg,len,flags,to,tolen);if(ret<0){printf("sendto socket error\n");goto again;}return ret;
}int Recvfrom(int sockfd, void *buf, int len, unsigned int flags, struct sockaddr *from, socklen_t *fromlen){int ret;
again:	ret=recvfrom(sockfd,buf,len,flags,from,fromlen);if(ret<0){printf("recvfrom socket error\n");goto again;				}return ret;
}

上述为封装函数，包括tcp_server,tcp_client已经后续的udp_server

2.socket_tcp_server.c与socket_tcp_client.c

1.socket_tcp_server.c

#include "socket_udp_server.h"
#include "socket_tcp_server.h"
#include "socket_wrap.h"
#include "ctype.h"static char ReadBuff[BUFF_SIZE];void vUdpServerTask(){int 	 sfd, n, i;struct sockaddr_in server_addr, client_addr;socklen_t	client_addr_len;int optval=1;//创建socketsfd=Socket(AF_INET, SOCK_DGRAM, 0);setsockopt(sfd,SOL_SOCKET ,SO_BROADCAST,&optval,sizeof(optval));//绑定socketserver_addr.sin_family 			= AF_INET;server_addr.sin_port   			= htons(SERVER_PORT);server_addr.sin_addr.s_addr = htonl(INADDR_ANY);Bind(sfd, (struct sockaddr *)&server_addr, sizeof(server_addr));//处理client_addr_len=sizeof(client_addr);while(1){//等待客户端发送数据n = Recvfrom(sfd, ReadBuff, BUFF_SIZE, 0, (struct sockaddr *)&client_addr, &client_addr_len);ReadBuff[n] = '\0';printf("recv data:%s\r\n",ReadBuff);//进行大小写转换for(i = 0; i < n; i++){	ReadBuff[i] = toupper(ReadBuff[i]);		}//写回客户端Sendto(sfd, ReadBuff, n, 0, (struct sockaddr *)&client_addr, client_addr_len);}}

2.socket_tcp_client.c

#include "socket_tcp_server.h"
#include "socket_tcp_client.h"
#include "socket_wrap.h"
#include "ctype.h"
#include "FreeRTOS.h"
#include "task.h"#include "string.h"static char ReadBuff[BUFF_SIZE];void vTcpClientTask(void)
{int 	 cfd, n, i, ret;struct sockaddr_in server_addr;//	int so_reuseaddr_val = 1;
again://创建socketcfd = Socket(AF_UNSPEC, SOCK_STREAM, 0);//使能socket层 心跳检测
//	setsockopt(cfd, SOL_SOCKET, SO_REUSEADDR, &so_reuseaddr_val, sizeof(int));server_addr.sin_family 			= AF_INET;server_addr.sin_port   			= htons(SERVER_PORT);server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);	//连接到服务器//connect 其实是一个阻塞接口，内部要完成TCP的三次握手，当然有超时机制，所以我们需要等一段时间，才能重新连接到服务器ret = connect(cfd, (struct sockaddr*)&server_addr, sizeof(server_addr));if(ret < 0){//100ms去连接一次服务器vTaskDelay(1000);printf("connect fail\r\n");goto again;}printf("server is connect ok\r\n");while(1){//等待服务器发送数据n = Read(cfd, ReadBuff, BUFF_SIZE);if(n <= 0){goto again;}//进行大小写转换for(i = 0; i < n; i++){ReadBuff[i] = toupper(ReadBuff[i]);		}//写回服务器n = Write(cfd, ReadBuff, n);if(n <= 0){goto again;}}
}

结果：pc端的COMMBOX创建或者关闭服务器或者客户端时，串口都会打印出内容，提示打开或者关闭。