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				1024

void 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socket
	sfd = 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socket
	bind(sfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
	//监听socket
	listen(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socket
	cfd = 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_H

void 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socket
	if(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socket
	sfd=Socket(AF_INET, SOCK_DGRAM, 0);
	setsockopt(sfd,SOL_SOCKET ,SO_BROADCAST,&optval,sizeof(optval));
	
	//绑定socket
	server_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socket
	cfd = 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。