taglinefilesource code
sock_wspace411net/inet/packet.csock_wspace,
sock_wspace408net/inet/raw.csock_wspace,
sock_wspace268net/inet/sock.hextern unsigned long    sock_wspace(struct sock *sk);
sock_wspace3819net/inet/tcp.csock_wspace,
sock_wspace749net/inet/udp.csock_wspace,