树莓派3B--通过TCP远程控制GPIO（C++）
一、分析
1、GPIO口初始化借助wiringPi；
2、利用linux下socket中的API，进行TCP通信
二、一个服务端和一个客户端
1、server端
//
/*************************************************************************
> File Name: server.c
> Author: Sen
> Date: 2018-5-8
************************************************************************/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
const int port = 8888;
const char* ip = "192.168.1.88";
int main()
{
//创建套接字,即创建socket
int ser_sock = socket(AF_INET, SOCK_STREAM, 0);
if(ser_sock < 0)
{
//创建失败
perror("socket");
return 1;
}
//绑定信息，即命名socket
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
//inet_addr函数将用点分十进制字符串表示的IPv4地址转化为用网络
//字节序整数表示的IPv4地址
addr.sin_addr.s_addr = inet_addr(ip);
if(bind(ser_sock, (struct sockaddr*)&addr, sizeof(addr)) < 0)
{
//命名失败
perror("bind");
return 2;
}
//监听socket
int listen_sock = listen(ser_sock, 5);
if(listen_sock < 0)
{
//监听失败
perror("listen");
return 3;
}
//接受连接
//系统调用从listen监听队列中接受一个连接
//int accept(int sockfd, struct sockaddr* addr, socklen_t* addrlen)
//sockfd参数是执行过listen系统调用的监听socket；addr参数用来获取被
//接受连接的远端socket地址，该socket地址的长度由addrlen参数指出
//accept成功时返回一个新的连接socket，该socket唯一的标识了被接受
//的这个连接，服务器可通过读写该socket来与被接受连接对应的客户端通信
struct sockaddr_in peer;
socklen_t peer_len;
char buf[1024];
int accept_fd = accept(ser_sock, (struct sockaddr*)&peer, &peer_len);
if(accept_fd < 0)
{
perror("accept");
return 4;
}
else
{
printf("connected with ip: %s and port: %d\n", inet_ntop(AF_INET,&peer.sin_addr, buf, 1024), ntohs(peer.sin_port));
}
wiringPiSetup();
pinMode(0, OUTPUT);
while(1)
{
memset(buf, '\0', sizeof(buf));
ssize_t size = read(accept_fd, buf, sizeof(buf) - 1);
if (size > 0)
{
printf("client#: %s\n", buf);
if (size = 1)
{
//control GPIO.0
int tmp = atoi(buf);
if (tmp == 1)
{
digitalWrite(0, HIGH);
} else {
digitalWrite(0, LOW);
}
}
}
else if(size == 0)
{
digitalWrite(0, LOW);
printf("read is done...\n");
//break;
}
else
{
digitalWrite(0, LOW);
perror("read");
//break;
}
}
close(ser_sock);
return 0;
}
// 2、client端
//
/*************************************************************************
> File Name: client.c
> Author: Sen
> Date: 2018-5-8
************************************************************************/
#include
#include
#include
#include
#include
#include
#include
#include
const int port = 8888;
const char* ip = "192.168.1.88";
int main()
{
//创建套接字,即创建socket
int clt_sock = socket(AF_INET, SOCK_STREAM, 0);
if(clt_sock < 0)
{
//创建失败
perror("socket");
return 1;
}
//绑定信息，即命名socket
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
//inet_addr函数将用点分十进制字符串表示的IPv4地址转化为用网络
//字节序整数表示的IPv4地址
addr.sin_addr.s_addr = inet_addr(ip);
//不需要监听
//发起连接
// struct sockaddr_in peer;
socklen_t addr_len = sizeof(addr);
int connect_fd = connect(clt_sock, (struct sockaddr*)&addr, addr_len);
if(connect_fd < 0)
{
perror("connect");
return 2;
}
char buf[1024];
while(1)
{
memset(buf, '\0', sizeof(buf));
printf("client please enter: ");
fflush(stdout);
ssize_t size = read(0, buf, sizeof(buf) - 1);
if(size > 0)
{
buf[size - 1] = '\0';
}
else if(size == 0)
{
printf("read is done...\n");
break;
}
else
{
perror("read");
return 4;
}
write(clt_sock, buf, strlen(buf));
}
close(clt_sock);
return 0;
}
//
三、一个服务端和多个客户端
1、server端
//
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define PORT 7654
#define QUEUE_SIZE 10
#define BUFFER_SIZE 1024
//传进来的sockfd，就是互相建立好连接之后的socket文件描述符
//通过这个sockfd，可以完成 [服务端]<--->[客户端] 互相收发数据
void str_echo(int sockfd)
{
char buffer[BUFFER_SIZE];
pid_t pid = getpid();
while(1)
{
memset(buffer,0,sizeof(buffer));
int len = recv(sockfd, buffer, sizeof(buffer),0);
if(strcmp(buffer,"exit\n")==0)
{
printf("child process: %d exited.\n",pid);
break;
}
if (len > 0)
{
printf("client#: %s\n", buffer);
if (len = 1 && buffer[0] == '1')
{
digitalWrite(0, HIGH);
} else {
digitalWrite(0, LOW);
}
} else if (len == 0) {
digitalWrite(0, LOW);
printf("read is done...\n");
} else {
digitalWrite(0, LOW);
perror("read");
}
printf("pid:%d receive:\n",pid);
//fputs(buffer, stdout);
send(sockfd, buffer, len, 0);
}
close(sockfd);
}
int main(int argc, char **argv)
{
//GPIO
wiringPiSetup();
pinMode(0, OUTPUT);
//定义IPV4的TCP连接的套接字描述符
int server_sockfd = socket(AF_INET,SOCK_STREAM, 0);
//定义sockaddr_in
struct sockaddr_in server_sockaddr;
server_sockaddr.sin_family = AF_INET;
server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
server_sockaddr.sin_port = htons(PORT);
//bind成功返回0，出错返回-1
if(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1)
{
perror("bind");
exit(1);//1为异常退出
}
printf("bind success.\n");
//listen成功返回0，出错返回-1，允许同时帧听的连接数为QUEUE_SIZE
if(listen(server_sockfd,QUEUE_SIZE) == -1)
{
perror("listen");
exit(1);
}
printf("listen success.\n");
for(;;)
{
struct sockaddr_in client_addr;
socklen_t length = sizeof(client_addr);
//进程阻塞在accept上，成功返回非负描述字，出错返回-1
int conn = accept(server_sockfd, (struct sockaddr*)&client_addr,&length);
if(conn<0)
{
perror("connect");
exit(1);
}
printf("new client accepted.\n");
pid_t childid;
if(childid=fork()==0)//子进程
{
printf("child process: %d created.\n", getpid());
close(server_sockfd);//在子进程中关闭监听
str_echo(conn);//处理监听的连接
exit(0);
}
}
printf("closed.\n");
close(server_sockfd);
return 0;
}
// 2、client端
//
/*************************************************************************
> File Name: client.c
> Author: Sen
> Date: 2018-5-8
************************************************************************/
#include
#include
#include
#include
#include
#include
#include
#include
const int port = 7654;
const char* ip = "192.168.1.32";
int main()
{
//创建套接字,即创建socket
int clt_sock = socket(AF_INET, SOCK_STREAM, 0);
if(clt_sock < 0)
{
//创建失败
perror("socket");
return 1;
}
//绑定信息，即命名socket
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
//inet_addr函数将用点分十进制字符串表示的IPv4地址转化为用网络
//字节序整数表示的IPv4地址
addr.sin_addr.s_addr = inet_addr(ip);
//不需要监听
//发起连接
// struct sockaddr_in peer;
socklen_t addr_len = sizeof(addr);
int connect_fd = connect(clt_sock, (struct sockaddr*)&addr, addr_len);
if(connect_fd < 0)
{
perror("connect");
return 2;
}
char buf[1024];
while(1)
{
memset(buf, '\0', sizeof(buf));
printf("client please enter: ");
fflush(stdout);
ssize_t size = read(0, buf, sizeof(buf) - 1);
if(size > 0)
{
buf[size - 1] = '\0';
}
else if(size == 0)
{
printf("read is done...\n");
break;
}
else
{
perror("read");
return 4;
}
write(clt_sock, buf, strlen(buf));
}
close(clt_sock);
return 0;
}
//