//server.c
1
#include <stdlib.h>
2#include <stdio.h>
3#include <errno.h>
4#include <string.h>
5#include <unistd.h>
6#include <netdb.h>
7#include <sys/socket.h>
8#include <netinet/in.h>
9#include <sys/types.h>
10#include <arpa/inet.h>
11
12int main(int argc, char *argv[])
13
{
14
int sockfd,new_fd;
15 struct sockaddr_in server_addr;
16 struct sockaddr_in client_addr;
17 int sin_size,portnumber;
18 char hello[]="Hello! Are You Fine?\n";
19
20 if(argc!=2)
21
{
22 fprintf(stderr,"Usage:%s portnumber\a\n",argv[0]);
23 exit(1);
24
}
25
26 if((portnumber=atoi(argv[1]))<0)
27 {
28 fprintf(stderr,"Usage:%s portnumber\a\n",argv[0]);
29 exit(1);
30 }
31
32 /**//* 服务器端开始建立socket描述符 */
33 if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
34 {
35 fprintf(stderr,"Socket error:%s\n\a",strerror(errno));
36 exit(1);
37 }
38
39 /**//* 服务器端填充 sockaddr结构 */
40 bzero(&server_addr,sizeof(struct sockaddr_in));
41 server_addr.sin_family=AF_INET;
42 server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
43 server_addr.sin_port=htons(portnumber);
44
45 /**//* 捆绑sockfd描述符 */
46 if(bind(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1)
47 {
48 fprintf(stderr,"Bind error:%s\n\a",strerror(errno));
49 exit(1);
50 }
51
52 /**//* 监听sockfd描述符 */
53 if(listen(sockfd,5)==-1)
54 {
55 fprintf(stderr,"Listen error:%s\n\a",strerror(errno));
56 exit(1);
57 }
58
59 while(1)
60 {
61 /**//* 服务器阻塞,直到客户程序建立连接 */
62 sin_size=sizeof(struct sockaddr_in);
63 if((new_fd=accept(sockfd,(struct sockaddr *)(&client_addr),&sin_size))==-1)
64 {
65 fprintf(stderr,"Accept error:%s\n\a",strerror(errno));
66 exit(1);
67 }
68
69 fprintf(stderr,"Server get connection from %s\n",
70 inet_ntoa(client_addr.sin_addr));
71 if(write(new_fd,hello,strlen(hello))==-1)
72 {
73 fprintf(stderr,"Write Error:%s\n",strerror(errno));
74 exit(1);
75 }
76 /**//* 这个通讯已经结束 */
77 close(new_fd);
78 /**//* 循环下一个 */
79 }
80 close(sockfd);
81 exit(0);
82
}
//client.c
1#include <stdlib.h>
2#include <stdio.h>
3#include <errno.h>
4#include <string.h>
5#include <unistd.h>
6#include <netdb.h>
7#include <sys/socket.h>
8#include <netinet/in.h>
9#include <sys/types.h>
10#include <arpa/inet.h>
11
12int main(int argc, char *argv[])
13{
14 int sockfd;
15 char buffer[1024];
16 struct sockaddr_in server_addr;
17 struct hostent *host;
18 int portnumber,nbytes;
19
20 if(argc!=3)
21 {
22 fprintf(stderr,"Usage:%s hostname portnumber\a\n",argv[0]);
23 exit(1);
24 }
25
26 if((host=gethostbyname(argv[1]))==NULL)
27 {
28 fprintf(stderr,"Gethostname error\n");
29 exit(1);
30 }
31
32 if((portnumber=atoi(argv[2]))<0)
33 {
34 fprintf(stderr,"Usage:%s hostname portnumber\a\n",argv[0]);
35 exit(1);
36 }
37
38 /**//* 客户程序开始建立 sockfd描述符 */
39 if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
40 {
41 fprintf(stderr,"Socket Error:%s\a\n",strerror(errno));
42 exit(1);
43 }
44
45 /**//* 客户程序填充服务端的资料 */
46 bzero(&server_addr,sizeof(server_addr));
47 server_addr.sin_family=AF_INET;
48 server_addr.sin_port=htons(portnumber);
49 server_addr.sin_addr=*((struct in_addr *)host->h_addr);
50
51 /**//* 客户程序发起连接请求 */
52 if(connect(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1)
53 {
54 fprintf(stderr,"Connect Error:%s\a\n",strerror(errno));
55 exit(1);
56 }
57
58 /**//* 连接成功了 */
59 if((nbytes=read(sockfd,buffer,1024))==-1)
60 {
61 fprintf(stderr,"Read Error:%s\n",strerror(errno));
62 exit(1);
63 }
64 buffer[nbytes]='\0';
65 printf("I have received:%s\n",buffer);
66 /**//* 结束通讯 */
67 close(sockfd);
68 exit(0);
69}