/*
** server.c -- a stream socket server demo from Beejs Networking Guide at http://www.ecst.csuchico.edu/~beej/guide/net/#bind
*/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>

#define MYPORT 3490    /* the port users will be connecting to */

#define BACKLOG 10     /* how many pending connections queue will hold */

main()
{
    int sockfd, new_fd;  /* listen on sock_fd, new connection on new_fd */
    struct sockaddr_in my_addr;    /* my address information */
    struct sockaddr_in their_addr; /* connector's address information */
    int sin_size;

/* Creating a socket   */
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

/* INET information */
    my_addr.sin_family = AF_INET;         /* host byte order */
    my_addr.sin_port = htons(MYPORT);     /* short, network byte order */
    my_addr.sin_addr.s_addr = INADDR_ANY; /* automatically fill with my IP */
    bzero(&(my_addr.sin_zero), 8);        /* zero the rest of the struct */

/* Binding the socket to the port 3490 */
    if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) {
        perror("bind");
        exit(1);
    }

/* Listiening for incoming connections */

    if (listen(sockfd, BACKLOG) == -1) {
        perror("listen");
        exit(1);
    }

    while(1) {  /* main accept() loop */
        sin_size = sizeof(struct sockaddr_in);
        if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1) {
            perror("accept");
            continue;
        }
        printf("server: got connection from %s\n",inet_ntoa(their_addr.sin_addr));
        if (!fork()) { /* this is the child process */
            if (send(new_fd, "Hello, world!\n", 14, 0) == -1)
                perror("send");
            close(new_fd);
            exit(0);
        }
        close(new_fd);  /* parent doesn't need this */

        while(waitpid(-1,NULL,WNOHANG) > 0); /* clean up all child processes */

/* Closing sockets important to avoid address already in use error */
	close(sockfd);
    }
}