eon/networking/socket.h

#include <unistd.h> 
#include <stdio.h> 
#include <sys/socket.h> 
#include <stdlib.h> 
#include <netinet/in.h>
#include <strings.h>

/**
 * 
 * socket struct for building sockets...
 * This will hold both listening sockets and connection sockets
 * TCP AND UDP!
 * 
 */
typedef struct Socket {
    
    int socketfd; //socket id
    int client_socketfd; // this is the int you get when you call accept()
    int port; // port information
    struct sockaddr_in address; // sockaddr_in struct
    struct Socket *next; // next in the linked list
    
} Socket;
//head of the linked list of sockets
struct Socket *_socket_head = NULL;
/**
 * This is used by a thread to listen for incoming
 * connections
 * 
 */

void doprocessing (int sock) {
   int n;
   char buffer[256];
   bzero(buffer,256);
   while(1) {
       n = read(sock,buffer,255);
       
       if (n < 0) {
          perror("ERROR reading from socket");
          exit(1);
       }
       
       printf("Here is the message: %s\n",buffer);
       n = write(sock,"I got your message",18);
       
       if (n < 0) {
          perror("ERROR writing to socket");
          exit(1);
       }
   }
	
}
/**
 * 
 * This function creates a listening function...
 * @params takes a an int for a port.
 * @return An active listening socket for incoming connections
 * 
 */
Socket create_lsocket(int _port, int _connection_amount) {
    
    Socket *newSocket = malloc(sizeof(Socket));
    
    //sockaddr_in struct stuff (making a new sockaddr_in and giving it details)
    struct sockaddr_in address; // make a struct of type sockaddr_in
    int addr_size = sizeof(address); // size of addess in decimal form
    
    // filling our struct with info
    address.sin_family = AF_INET; //ipv4....
    address.sin_addr.s_addr = INADDR_ANY; // any local address I.E :0.0.0.0
    address.sin_port = htons(_port); // htons takes a decimal number and converts it to network
    
    
    //this is a socket handler, like a file handler...
    int socketfd = socket(AF_INET, SOCK_STREAM, 0);
    
    // if the socks returns 0 then exit
    if (socketfd == 0) {
        
        printf("SOCKET FAILED!\n");
        exit(1);
        
    } 
    
    //lets bind that socket now
    int bindRes = bind(socketfd, (struct sockaddr *)&address, sizeof(address));
    if(bindRes < 0) {
        
        printf("BIND FAILED! WITH CODE: %d\n", bindRes);
        exit(1);
        
    }
    
    listen(socketfd, 5);
    while(1) {
        
        int newsockfd = accept(socketfd, (struct sockaddr *) &address, &addr_size);
        
        if (newsockfd < 0) {
            
            printf("ERROR LISTENING!\n");
            exit(1);
            
        }
        int pid = fork();
        if (pid == 0) {
            
            printf("NEW CLIENT!\n");
            doprocessing(newsockfd);
            exit(0);
            
        }
        
    }
    
    newSocket->socketfd = socketfd;
    newSocket->port = _port;
    newSocket->address = address;
    newSocket->next = NULL;
    // if the socket head is empty we are going to malloc the head and then start
    // the linked list of sockets
    if (_socket_head == NULL) {
        
        _socket_head = malloc(sizeof(Socket));
        _socket_head->next = newSocket;
        
        
    }
    
    
}