sbfull
if ((so->so_state & SS_CANTRCVMORE) == 0 && !sbfull(&so->so_rcv)) {
if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
static int sbfull(struct sockbuf *sb);