socket编程热身程序

Posted 2020-07-31 自由石匠

 1 /*server.c*/
 2 #include <stdio.h>
 3 #include <arpa/inet.h>
 4 #include <sys/types.h>          /* See NOTES */
 5 #include <sys/socket.h>
 6 #include <netinet/in.h>
 7 #include <stdlib.h>
 8 #include <unistd.h>
 9 #define  err_log(errlog) do{ perror(errlog); exit(1);}while(0)
10 int main(int argc, const char *argv[])
11 {
12     int sockfd;
13     int acceptfd;
14     struct sockaddr_in  serveraddr, clientaddr;
15    
16     if (argc != 3)
17     {
18         fprintf(stderr,"Usage:%s serverip port.\n", argv[0]);
19         return -1;
20     }
21 /*server端 第一步：socket 创建套接字*/
22     if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
23     {
24         err_log("fail to socket");
25     }
26    /*server端 第二步： 填充网络信息结构体*/
27     serveraddr.sin_family = AF_INET;
28     serveraddr.sin_addr.s_addr = inet_addr(argv[1]);//argv[1]:由手动输入，终端的第二个参数
29     serveraddr.sin_port = htons(atoi(argv[2]));//htons 将本地字节序变为网络字节序，atoi将数字类字符串转化为数字，如字符串“80” 变为数字80
30   /*server端 第三步 ：bind() 绑定*/
31     if(bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
32     {
33         err_log("fail to bind");
34     }
35   /*server端 第四步：listen() 监听*/
36     if(listen(sockfd, 15) < 0)
37     {
38         err_log("fail to listen");
39     }
40     
41     socklen_t  addrlen = sizeof(struct sockaddr_in);
         /*接收客户端的连接请求*/
42     acceptfd = accept(sockfd, (struct sockaddr *)&clientaddr, &addrlen);
43     
44     if(acceptfd < 0)
45     {
46         err_log("fail to acceptfd");
47     }
48 
49     printf("%s --> %d\n", inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port));
      /*inet_ntoa函数将网络字节序的IP地址转换为十进制的字符串*/
      /*ntohs 将网络端口号转换为本地端口号*/
50     close(acceptfd); //关闭文件描述符
51     close(sockfd);//关闭文件描述符

52     return 0; 
    }

53 

 1 /*client*/
 2 #include <stdio.h>
 3 #include <arpa/inet.h>
 4 #include <sys/types.h>          /* See NOTES */
 5 #include <sys/socket.h>
 6 #include <netinet/in.h>
 7 #include <stdlib.h>
 8 #include <unistd.h>
 9 #define  err_log(errlog) do{ perror(errlog); exit(1);}while(0)
10 
11 int main(int argc, const char *argv[])
12 {
13     int sockfd;
14     int acceptfd;
15     struct sockaddr_in  serveraddr, clientaddr;
16 
17     if(argc != 3)
18     {
19         fprintf(stderr,"Usage:%s serverip port.\n", argv[0]);
20         return -1;
21     }
22     /*client端 第一步：socket套接字*/
23     if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
24     {
25         err_log("fail to socket");
26     }
27    /*client端 第二部：填充网络信息结构体*/
28     serveraddr.sin_family = AF_INET;
29     serveraddr.sin_addr.s_addr = inet_addr(argv[1]);
30     serveraddr.sin_port = htons(atoi(argv[2]));
31    /*client端 第三步：连接服务器端*/
32   if(connect(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
33     {
34         err_log("fail to connect");
35     }
36   close(sockfd);//关闭文件描述符
37   return 0;
38 }