struct sockaddr_in {
short sin_family;
u_short sin_port; /*Port number */
struct in_addr sin_addr; /*Internet address */
char sin_zero[8];
};
struct sockaddr_in6 {
short sin6_family;
u_short sin6_port;
u_long sin6_flowinfo;
struct in6_addr sin6_addr;
u_long sin6_scope_id;
};