socket 编程简单的TCP

客户端向服务器发出连接请求后，服务器端写入数据发送给客户端，在客户端显示。

server:

 1 #include <stdlib.h>
 2 #include <stdio.h>
 3 #include <errno.h>
 4 #include <string.h>
 5 #include <netdb.h>
 6 #include <sys/types.h>
 7 #include <netinet/in.h>
 8 #include <sys/socket.h>
 9 #include <unistd.h>
10 
11 #define MAXSIZE 1024
12 
13 int main(int argc, char* argv[])
14 {
15     int sockfd, new_fd;
16     struct sockaddr_in server_addr;
17     struct sockaddr_in client_addr;
18     int sin_size, portnumber;
19     char buf[MAXSIZE];
20     if(argc != 2)
21     {
22         fprintf(stderr,"Usage: %s portnumbera
",argv[0]);
23         exit(1);
24     }
25     if((portnumber = atoi(argv[1]))<0)
26     {
27         /*获得命令行的第二个参数端口号，atoi()把字符串转换成整形数*/
28         fprintf(stderr,"usage: %s portnumbera
",argv[0]);
29         exit(1);
30     }
31     /*服务器开始建立socket描述符*/
32     sockfd = socket(AF_INET,SOCK_STREAM,0);
33     
34     /*服务器端填充sockaddr结构*/
35     bzero(&server_addr,sizeof(struct sockaddr_in));
36     server_addr.sin_family=AF_INET;
37     server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
38     server_addr.sin_port = htons(portnumber);
39     
40     /*调用bind函数绑定端口*/
41     bind(sockfd,(struct sockaddr*)(&server_addr),sizeof(struct sockaddr));
42     
43     /*监听sockfd描述符，同时处理的最大链接请求数为5*/
44     listen(sockfd,5);
45 
46     /*服务器阻塞，等待接收链接请求，直到客户端发送链接请求*/
47     while(1)
48     {
49         sin_size = sizeof(struct sockaddr_in);
50         /*调用accept接受一个连接请求*/
51         if((new_fd = accept(sockfd,(struct sockaddr*)(&client_addr),&sin_size))==-1)
52         {
53             printf("accept error!
");
54             exit(1);
55         }
56         /*TCP链接已建立，打印申请链接的客户机的IP地址*/
57         printf("Server get connection from %d
",inet_ntoa(client_addr.sin_addr));
58         /*提示用户输入要发送的数据，长度小于缓冲区的长度*/
59         printf("Connected successful, please input the message[less than 1024 bytes]:
");
60         
61         /*从终端输入要发送的数据，放到buf缓冲区*/
62         fgets(buf,sizeof(buf),stdin);
63         
64         /*调用write发送数据*/
65         if(write(new_fd,buf,strlen(buf))==-1)
66         {
67             printf("write error!
");
68             exit(1);
69         }
70         close(new_fd);
71     }
72     close(sockfd);
73     return 0;
74 }

client:

 1 #include <stdlib.h>
 2 #include <stdio.h>
 3 #include <errno.h>
 4 #include <string.h>
 5 #include <netdb.h>
 6 #include <sys/types.h>
 7 #include <netinet/in.h>
 8 #include <sys/socket.h>
 9 
10 int main(int argc, char* argv[])
11 {
12     int sockfd;
13     char buffer[1024];
14     /*定义服务器端套接口数据结构*/
15     struct sockaddr_in server_addr;
16     struct hostent *host;
17     int portnumber, nbytes;
18     if(argc!=3)
19     {
20         printf("Usage: %s hostname portnumbera
",argv[0]);
21         exit(1);
22     }
23     /*获得命令行的第二个参数--主机名*/
24     if((host=gethostbyname(argv[1]))==NULL)
25     {
26         printf("get host name error
");
27         exit(1);
28     }
29     /*获得第三个参数，端口号*/
30     if((portnumber = atoi(argv[2]))<0)
31     {
32         printf("port number error
");
33         exit(1);
34     }
35     /*客户程序开始建立sockfd描述符*/
36     if((sockfd = socket(AF_INET,SOCK_STREAM,0))==01)
37     {
38         printf("socket error
");
39         exit(1);
40     }
41     /*客户程序填充服务端资料*/
42     bzero(&server_addr,sizeof(server_addr));
43     server_addr.sin_family = AF_INET;
44     server_addr.sin_port = htons(portnumber);
45     server_addr.sin_addr = *((struct in_addr*)host->h_addr);
46     /*客户程序发起连接请求*/
47     connect(sockfd,(struct sockaddr*)(&server_addr),sizeof(struct sockaddr));
48     
49     /*调用read读取服务器发送来的数据*/
50     if((nbytes = read(sockfd,buffer,1024))==-1)
51     {
52         printf("read error
");
53         exit(1);
54     }
55     buffer[nbytes] = '';
56     printf("I have received:%s
",buffer);
57     close(sockfd);
58     return 0;
59 }
60

socket 编程 简单的TCP

socket 编程简单的TCP