创建一个简单的echo服务器

 1 //Author:kunshanpipixia
 2 #include <stdio.h>
 3 #include <stdlib.h>
 4 #include <string.h>
 5 #include <pthread.h>
 6 #include <unistd.h>
 7 #include <errno.h>
 8 #include <sys/socket.h>
 9 #include <arpa/inet.h>
10 #include <ctype.h>
11 #define PORT 40000
12 #define MESSAGE_LEN 1024
13 int main(int argc, char* argv[])
14 {
15     int socket_fd,accept_fd;
16     int on=1;
17     struct sockaddr_in localaddr,remoteaddr;
18     int ret=-1;
19     int backlog=10;
20     socket_fd=socket(AF_INET,SOCK_STREAM,0);
21     char in_buff[MESSAGE_LEN]={0,};
22     if(socket_fd==-1)
23     {
24         printf("Failed");
25         exit(-1);
26     }
27     ret=setsockopt(socket_fd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on));
28     if(ret==-1)
29     {
30         printf("Failed to set socket options");
31     }
32     localaddr.sin_family=AF_INET;
33     localaddr.sin_port=PORT;
34     localaddr.sin_addr.s_addr=INADDR_ANY; 
35     bzero(&(localaddr.sin_zero),8);
36     ret=bind(socket_fd,(struct sockaddr *)&localaddr,sizeof(struct sockaddr));
37     if(ret==-1)
38     {
39         printf("Failed to bind");
40         exit(-1);
41     }
42     ret=listen(socket_fd,backlog);
43     if(ret==-1)
44     {
45         printf("failed to listen");
46         exit(-1);
47     }
48     for(;;)
49     {
50         socklen_t addr_len=sizeof(struct sockaddr);
51         accept_fd=accept(socket_fd,(struct sockaddr *)&remoteaddr,&addr_len);
52           
53     }
54     for(;;)
55     {
56         ret=recv(accept_fd,(void*)in_buff,MESSAGE_LEN,0);
57         if(ret==0)
58         {
59             break;
60         }
61         printf("%x",in_buff);
62         send(accept_fd,(void*)in_buff,MESSAGE_LEN,0);
63     }
64     close(accept_fd);
65 close(socket_fd);
66 return 0;
67 }