Socket简单的server-client编程

一、代码

Socket Server端：

/****************************
*****简单的socket server程序*
*****************************/
#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<sys/time.h>
#include<sys/types.h>
#include<sys/select.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<errno.h>

#define MAX_LINE 128
#define LISTENQ 20
#define PORT 8888

/*Socket Client*/
int main(int argc, char *argv[])
{
	printf("%d,%s\n",argc,argv[1]);
	int socket_fd = 0;
	int listen_fd = 0;
	int connfd;
	int con_fd = 0;
	int fd_flag = 0;
	int buflen = 0;
	socklen_t length;
	fd_set read_fd;
	char buf[1024] = {0};
	char Mesg[] = "HelloWorld";
	char Recv[MAX_LINE] = {0};
	struct timeval timeout;
	timeout.tv_sec = 5;
	timeout.tv_usec = 0;
	struct sockaddr_in server_addr, client_addr; 
	if((socket_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
	{
		perror("create socket error:\n");
		exit(EXIT_FAILURE);
	}

	bzero(&server_addr, sizeof(server_addr));
	
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	server_addr.sin_port = htons(PORT);

	if(bind(socket_fd, (struct sockaddr *)&server_addr,sizeof(server_addr)) == -1)
	{
		perror("bind error:%d\n");
		exit(EXIT_FAILURE);
	}
	
	if(listen(socket_fd,LISTENQ) == -1)
	{  
		perror("listen error:%d\n");
		exit(EXIT_FAILURE);
	}
	else
	{  
		printf("listen alright\n");
	}


	while(1)
	{  
		FD_ZERO(&read_fd);
		FD_SET(socket_fd, &read_fd);
		fd_flag = select(socket_fd+1, &read_fd, NULL, NULL, NULL);
		if(FD_ISSET(socket_fd, &read_fd))
		{
			length = sizeof(client_addr);
			printf("accept connection\n");
			if((connfd = accept(socket_fd, (struct sockaddr *)&client_addr,&length)) < 0)
			{  
				perror("Server accept meet failure\n");
				exit(EXIT_FAILURE);
			}
			printf("Accept client ip:%s,port:%d\n",inet_ntoa(client_addr.sin_addr),client_addr.sin_port);
			if(read(connfd, buf, MAX_LINE) <= 0)
			{
				perror("Server read buf meet failure\n");
				exit(EXIT_FAILURE);
			}
			printf("Server has received buf:%s\n",buf);
			int length = write(connfd, Mesg, strlen(Mesg));
			printf("Write buf %s to client\n",Mesg);
		}
	}
	close(socket_fd);
	close(connfd);
	return 0;
}

Socket Client端：

/************************
简单的Sock Client端程序
*************************/
#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<sys/time.h>
#include<sys/types.h>
#include<sys/select.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<errno.h>

#define MAX_LINE 128
#define PORT 8888

/*Socket Client*/
int main(int argc, char *argv[])
{
	printf("%d,%s\n",argc,argv[1]);
	int socket_fd = 0;
	int fd_read = 0;
	int fd_write = 0;
	int buflen = 0;
	int write_len = 0;

	fd_set read_fd;

	char Recv[MAX_LINE] = {0};
	struct timeval timeout;
	timeout.tv_sec = 1;
	timeout.tv_usec = 0;
	struct sockaddr_in client_addr; 
	
	if((socket_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
	{
		perror("Socket initialization meet failure.\n");
		exit(EXIT_FAILURE);
	}

	bzero(&client_addr, sizeof(client_addr));
	
	client_addr.sin_family = AF_INET;	
	client_addr.sin_port = htons(PORT);
	
	if(inet_pton(AF_INET, argv[1], &client_addr.sin_addr) <= 0)
	{  
		perror("Addr transverse meet failure.\n");
		exit(EXIT_FAILURE);
	}

	if(connect(socket_fd, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0)
	{
		perror("Connect meet error\n");
		exit(EXIT_FAILURE);
	}

	write_len = write(socket_fd, argv[2], strlen(argv[2]));
	printf("Write buf to Server:%s and Buf length is:%d\n",argv[2], write_len);
	
	FD_ZERO(&read_fd);
	FD_SET(socket_fd, &read_fd);

	fd_read = select(socket_fd+1, &read_fd, NULL, NULL, &timeout);

	if(FD_ISSET(socket_fd,&read_fd))
	{
		printf("Select Read FD is ready and fd is:%d\n",socket_fd);	
		buflen = read(socket_fd, Recv, MAX_LINE);
		if(buflen)
		{
			printf("Read ok and buf is:%s\n",Recv);
		}
	}
	if(close(socket_fd) == 0)
	{
		printf("close fd right\n");
	}
	return 0;
}

二、Server端的编码步骤：

1.socket函数初始化一个基于TCP的socket_fd套接字;

2.通过bind函数绑定套接字结构体,指定IPV4协议族,监听本机的网口IP地址和指定端口;

3.listen函数开始监听CLIENT的请求;

4.然后通过在while循环中,select函数取获取可用的readfd集,可设置timeout;

5.通过FD_ISSET和select配合,发现可用的套接字,通过accept函数获取与client的连接;

6.通过read函数读取client发过来的数据;

7.通过write回复client消息;

8.close套接字;

三、Client端的编码步骤：

1.socket函数初始化一个基于TCP的socket_fd套接字;

2.直接通过connect函数往指定IP地址,端口,协议族发送连接请求,若连接成功则继续;

3.连接成功后,通过write函数往server端发送数据消息;

4.通过select函数取获取可读readfd,表明read可读权限后,调用read函数,获取server端发来的消息;

5.close套接字;

注:select函数中最后一个参数timeout可决定select函数是否阻塞;