POSIX TCP Daytime Iterative Server


Example

This is a TCP daytime iterative server kept as simple as possible.

#include <sys/types.h>   /* predefined types */ 
#include <unistd.h>      /* unix standard library */ 
#include <arpa/inet.h>   /* IP addresses conversion utilities */ 
#include <netinet/in.h>  /* sockaddr_in structure definition */
#include <sys/socket.h>  /* berkley socket library */ 
#include <stdio.h>       /* standard I/O library */ 
#include <string.h>      /* include to have memset */ 
#include <stdlib.h>      /* include to have exit */ 
#include <time.h>        /* time manipulation primitives */
 
#define MAXLINE 80 
#define BACKLOG 10 
 
int main(int argc, char *argv[]) 
{  
    int list_fd, conn_fd;  
    struct sockaddr_in serv_add; 
    char buffer[MAXLINE]; 
    time_t timeval; 
 
    /* socket creation third parameter should be IPPROTO_TCP but 0 is an
     * accepted value */  
    list_fd = socket(AF_INET, SOCK_STREAM, 0);
         
    /* address initialization */ 
    memset(&serv_add, 0, sizeof(serv_add));        /* init the server address */ 
    serv_add.sin_family = AF_INET;                 /* address type is IPV4 */ 
    serv_add.sin_port = htons(13);                 /* daytime port is 13 */ 
    serv_add.sin_addr.s_addr = htonl(INADDR_ANY);  /* connect from anywhere */ 
     
    /* bind socket */ 
    bind(list_fd, (struct sockaddr *)&serv_add, sizeof(serv_add));
        
    /* listen on socket */ 
    listen(list_fd, BACKLOG);

    while (1) 
    { 
        /* accept connection */ 
        conn_fd = accept(list_fd, (struct sockaddr *) NULL, NULL);
           
        timeval = time(NULL); 
        snprintf(buffer, sizeof(buffer), "%.24s\r\n", ctime(&timeval)); 
         
        write(conn_fd, buffer, strlen(buffer)); /* write daytime to client */ 
         
        close(conn_fd); 
    } 
     
    /* normal exit */ 
    close(list_fd); 
    exit(0); 
}