1 #include<stdio.h>
 2 #include <sys/types.h>          /* See NOTES */
 3 #include <sys/socket.h>
 4 #include <netinet/ip.h>
 5 #include <errno.h>
 6 #include <stdlib.h>
 7 #include <netinet/in.h>
 8 #include <arpa/inet.h>
 9 #include <unistd.h>
10 #include <string.h>
11 void do_service(int conn){
12 
13             char recvbuffer[1024];
14                 while(1){
15                     memset(recvbuffer,0,sizeof(recvbuffer));
16                     read(conn,&recvbuffer,sizeof(recvbuffer));
17                     fputs(recvbuffer,stdout);
18                     write(conn,recvbuffer,strlen(recvbuffer));
19                 }
20 }
21 int main(){
22     int socketfd;
23     socketfd=socket(PF_INET,SOCK_STREAM,0);
24     if(socketfd<0){
25         perror("socket");
26         exit(EXIT_FAILURE);
27     }
28 
29     struct sockaddr_in sockaddress;
30     sockaddress.sin_family=AF_INET;
31     sockaddress.sin_port=htons(5188);
32     sockaddress.sin_addr.s_addr=htonl(INADDR_ANY);//INADDR_ANY接收任何地址的连接
33     //sockaddress.sin_addr.s_addr=inet_addr("127.0.0.1");//也可以是这种方式
34 
35     int on=1;
36     if (setsockopt(socketfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on))<0){
37         perror("setsockopt");
38         exit(EXIT_FAILURE);
39     }
40 
41     if(bind(socketfd,(struct sockaddr*)&sockaddress,sizeof(sockaddress))<0){
42         perror("bind");
43         exit(EXIT_FAILURE);
44     }
45 
46     if ( listen(socketfd,SOMAXCONN)<0){
47         perror("listen");
48         exit(EXIT_FAILURE);
49     }
50 
51     int conn;
52     struct sockaddr_in peeraddr;
53     socklen_t len=sizeof(struct sockaddr_in);
54     pid_t pid;
55     while(1){
56         conn=accept(socketfd,(struct sockaddr*)&peeraddr,&len);
57         if (conn<0){
58             perror("accept");
59             exit(EXIT_FAILURE);
60         }
61         printf("client ip:%s port:%d\n",inet_ntoa(peeraddr.sin_addr),ntohs(peeraddr.sin_port));
62         pid=fork();
63         if (pid<0){//开启进程失败
64             perror("fork");
65             exit(EXIT_FAILURE);
66         }else if(pid==0){//进入子进程处理过程
67                    close(socketfd);
68            do_service(conn);
69         }else{//主进程处理过程
70             close(conn);//主进程执行到这后就不需要连接套接字了，关闭它
71         }
72     }
73     return 0;
74 
75 }