Linux（socket通信）--服务端与客户端编程

server.c

#include <stdio.h> 		//printf perror
#include <sys/socket.h>	//socket blind listen accept connect
#include <unistd.h>		//read and write
#include <sys/types.h>	//size_t，time_t，pid_t等类型
#include <stdlib.h>		//NULL
#include <string.h>		//sizeof
#include <netinet/in.h> 
#include <netdb.h>		//hostnent

#define PORT 2345
#define MAX_QUE_CONN 5 //最大的请求队列 
#define BUFFER_SIZE 1024 
int main(){
	struct sockaddr_in server_sockaddr,client_sockaddr;
	int sockfd,client_fd;
	int r_bytes;
	char buf[BUFFER_SIZE];
	
	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){
		perror("Socket error!\n");
		exit(1);
	}
	
	/*设置sockaddr_in 结构体中相关参数*/
	server_sockaddr.sin_family = AF_INET;			//Ipv4 
	server_sockaddr.sin_port = htons(PORT);			//htons:主机字节序（小）-> 网络字节序（大） 
	server_sockaddr.sin_addr.s_addr = INADDR_ANY;	//all ip can connect
	memset(server_sockaddr.sin_zero,0,8);			//填充0以保持与struct sockaddr同样大小 

	/*bind sockfd*/
	if (bind(sockfd, (struct sockaddr *)&server_sockaddr, sizeof(struct sockaddr)) == -1){
		perror("Bind error!\n");
		exit(1);
	}
	
	/*listen*/
	if ( listen( sockfd, MAX_QUE_CONN) == -1){
		perror("Listen error!\n");
		exit(1);
	}
	printf("Listening........\n");

	/*accept*/	
	int sin_size;
	if ((client_fd = accept(sockfd, (struct sockaddr *)&client_sockaddr, &sin_size)) == -1){
		perror("Accept error!\n");
		exit(1);
	}
	
	/*Recieve message from client*/
	memset(buf, 0, sizeof(buf));
	if((r_bytes = read(client_fd, buf, BUFFER_SIZE)) == -1){
		perror("Read error!\n");
		exit(1);
	}
	printf("Recieve a message: %s\n",buf);
	close(sockfd);
	return 0;
}

client.c

#include <stdio.h> 		//printf perror
#include <sys/socket.h>	//socket blind listen accept connect
#include <unistd.h>		//read and write
#include <sys/types.h>	//size_t，time_t，pid_t等类型
#include <stdlib.h>		//NULL exit
#include <string.h>		//sizeof
#include <netinet/in.h> 
#include <netdb.h>		//hostnent
#define PORT 2345
#define BUFFER_SIZE 1024
int main(int argc, char **argv){
	int sockfd,s_bytes;
	struct hostent *host;
	char buf[BUFFER_SIZE];
	struct sockaddr_in server_sockaddr;
	
	if( argc < 3){
		printf("Usage: ./client Hostname(or ip address) Text\n");
		exit(1);
	}
	
	/*地址解析函数*/
	if ((host = gethostbyname(argv[1])) == NULL){
		perror("gethostbyname error!\n");
		exit(1);
	}
	
	memset(buf, 0, sizeof(buf));
	sprintf(buf,"%s",argv[2]);
	
	/*Create socket*/
	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){
		perror("Socket error!\n");
		exit(1);
	}
	
	/*设置sockaddr_in 结构体中相关参数*/
	server_sockaddr.sin_family = AF_INET;			//Ipv4 
	server_sockaddr.sin_port = htons(PORT);			//htons:主机字节序（小）-> 网络字节序（大） 
	server_sockaddr.sin_addr = *((struct in_addr *)host->h_addr);				
	memset(server_sockaddr.sin_zero,0,8);			
	
	/*connect*/
	if((connect(sockfd, (struct sockaddr*)&server_sockaddr, sizeof(struct sockaddr)) == -1)){
		perror("Connect error!\n");
		exit(1);
	}
	
	/*send message to server*/
	if((s_bytes = write(sockfd, buf, sizeof(buf))) == -1){
		perror("Write error!\n");
		exit(1);
	}
	
	close(sockfd);
	return 0;
}