SOCKET DATA STRUCTURES
     struct sockaddr {
	  sa_family_t	sa_family;	/* address family */
	  char		sa_data[14];	/* up to 14 bytes of direct address */
    };

    struct in_addr {
        in_addr_t  s_addr;   /* an unsigned int */
    }

    struct sockaddr_in {
	  sa_family_t	 sin_family;    /* use AF_INET or PF_INET */
	  in_port_t	 sin_port;      /* in network byte order */
	  struct in_addr sin_addr; 
	  char		 sin_zero[8];
    };

    struct hostent {
        char *h_name;
        char **h_aliases;
        short h_addrtype;
        short h_length;
        char **h_addr_list;
    };
    #define h_addr   h_addr_list[0]