struct sockaddr_storage ss;
socklen_t sl = sizeof ss;
int len = recvfrom(s, buf, sizeof buf, MSG_DONTWAIT, (struct sockaddr *)&ss, &sl);
struct sockaddr_storage ss;
socklen_t sl = sizeof ss;
int len = recvfrom(s, buf, sizeof buf, MSG_DONTWAIT, (struct sockaddr *)&ss, &sl);