Linux下TCP编程

Myth丶恋晨 2022-06-02 07:24 135阅读 0赞

首先要建立服务器建立起socket，然后与本地的端口进行绑定，接着就开始接收客户端的请求并建立与它的连接，接下来，客户端发送的消息。

tcpserver.c代码：

int main()
    {
        struct sockaddr_in server_sockaddr,client_sockaddr;
        int sin_size,recvbytes;
        int sockfd, client_fd;
        char buf[BUFFER_SIZE];
    
        /* 建立socket连接 */
        if((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1)
        {
            perror("socket");
            exit(1);
        }
    
        printf("Socket id = %d\n",sockfd);
    
        /* 设置socket_in 结构体中相关的参数 */
        server_sockaddr.sin_family = AF_INET;               /* ipv4的协议 */
        server_sockaddr.sin_port = htons(PORT);             /* 设置端口 */
        server_sockaddr.sin_addr.s_addr = INADDR_ANY;       /* ip地址服务器这边的地址 */
        bzero(&(server_sockaddr.sin_zero),8);               /* 保持位数 */
    
        int i = 1;              /* 允许重复使用本地地址与套接字进行绑定 */
        setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR, &i,sizeof(i));
    
        /* 绑定函数bind（） */
        if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))== -1)
        {
            perror("bind");
            exit(1);
        }
    
        printf("bind success!\n");
    
        /* 调用listen（）函数，创建未处理请求的队列 */
        if( listen(sockfd, MAX_QUE_CONN_NM) == -1)
        {
            perror("listen");
            exit(1);
        }
        printf("Listening....\n");
    
        /* 调用accept（）function,waiting client connnectting */
        if((client_fd = accept(sockfd, (struct sockaddr *) & client_sockaddr,&sin_size)) == -1)
        {
            perror("accept");
            exit(1);
        }
    
        memset(buf,0,sizeof(buf));
    
        if((recvbytes = recv(client_fd,buf,BUFFER_SIZE,0)) == -1)
        {
            perror("recv");
            exit(1);
        }
    
        printf("Received a message :%s\n",buf);
        close(sockfd);
        exit(0);
    }

客户端的程序：

#include "myinclude.h"
    int main(int argc, char *argv[])
    {
        int sockfd,sendbytes;
        char buf[BUFFER_SIZE];
        struct hostent *host;
        struct sockaddr_in serv_adr;
    
        if(argc < 3)
        {
            fprintf(stderr,"USAGE:./client Hostname(or ipaddress)Text\n ");
            exit(1);
        }
    /* address resolution function */
        if((host = gethostbyname(argv[1])) == NULL)
        {
            perror("gethostbyname");
            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");
            exit(1);
        }
    /* set up the structure-related parameters of sockaddr_in */
        serv_adr.sin_family = AF_INET;
        serv_adr.sin_port = htons(PORT);
        serv_adr.sin_addr = *((struct in_addr *)host->h_addr);
        bzero(&(serv_adr.sin_zero),8);
    /* call connect function Initiate a connection to the server */
        if(connect(sockfd,(struct sockaddr *)&serv_adr,sizeof(struct sockaddr)) == -1)
        {
            perror("connect");  
            exit(1);
        }
    /* send messages to server */
        if((sendbytes = send(sockfd,buf,strlen(buf),0))==-1)
        {
            perror("Send");
            exit(1);
        }
    
        close(sockfd);
        exit(0);
    }

![这里写图片描述][SouthEast]

[SouthEast]: /images/20220602/090186485b3d4e25b0bad1ba8ead26b2.png